7.50.04 - Segger Microcontroller

A product of SEGGER Microcontroller GmbH & Co. KG

embOS/IP

Document: UM07001

Software version: 2.10

Revision: 0

Date: September 13, 2012

User & Reference Guide

CPU independant

TCP/IP stack for

embedded applications

www.segger.com

Disclaimer

Specifications written in this document are believed to be accurate, but are not guar-

anteed to be entirely free of error. The information in this manual is subject to

change for functional or performance improvements without notice. Please make sure

your manual is the latest edition. While the information herein is assumed to be

accurate, SEGGER Microcontroller GmbH & Co. KG (SEGGER) assumes no responsibil-

ity for any errors or omissions. SEGGER makes and you receive no warranties or con-

ditions, express, implied, statutory or in any communication with you. SEGGER

specifically disclaims any implied warranty of merchantability or fitness for a particu-

lar purpose.

You may not extract portions of this manual or modify the PDF file in any way without

the prior written permission of SEGGER. The software described in this document is

furnished under a license and may only be used or copied in accordance with the

terms of such a license.

Trademarks

Names mentioned in this manual may be trademarks of their respective companies.

Brand and product names are trademarks or registered trademarks of their respec-

tive holders.

Contact address

SEGGER Microcontroller GmbH & Co. KG

In den Weiden 11

D-40721 Hilden

Germany

Tel.+49 2103-2878-0

Fax.+49 2103-2878-28

E-mail: support@segger.com

Internet: http://www.segger.com

Manual versions

This manual describes the current software version. If any error occurs, inform us

and we will try to assist you as soon as possible.

Print date: September 13, 2012

Software Revision Date By Description

2.10 0 120913 OO

Minor updates and corrections.

Chapter "UPnP (Add-on)" added.

Chapter "VLAN" added.

Chapter "Core functions" updated.

* IP_NI_ForceCaps() added.

* IP_ARP_ConfigAgeout() added.

* IP_ARP_ConfigAgeoutNoReply() added.

* IP_ARP_ConfigAgeoutSniff() added.

* IP_ARP_ConfigAllowGratuitousARP() added.

* IP_ARP_ConfigMaxRetries() added.

* IP_ARP_ConfigNumEntries() added.

* IP_IFaceIsReadyEx() added.

* IP_IGMP_Add() added.

* IP_IGMP_JoinGroup() added.

* IP_IGMP_LeaveGroup() added.

Chapter "UDP zero-copy interface" updated.

* IP_UDP_GetFPort() added.

Chapter "Web server (Add-on)" updated.

* Information regarding file uploads added.

* More detailed description about multiuple connections

added.

* IP_WEBS_AddFileTypeHook() added.

* IP_WEBS_AddVFileHook() added.

* IP_WEBS_ConfigSendVFileHeader() added.

* IP_WEBS_ConfigSendVFileHookHeader() added.

* IP_WEBS_GetParaValuePtr() added.

* IP_WEBS_SendHeader() added.

Chapter "PPP/PPPoE (Add-on)" updated.

* IP_MODEM_Connect() added.

* IP_MODEM_Disconnect() added.

* IP_MODEM_GetResponse() added.

* IP_MODEM_SendString() added.

* IP_MODEM_SendStringEx() added.

* IP_MODEM_SetAuthInfo() added.

* IP_MODEM_SetConnectTimeout() added.

* IP_MODEM_SetInitCallback() added.

* IP_MODEM_SetInitString() added.

* IP_MODEM_SetSwitchToCmdDelay() added.

2.02c 0 120706 OO Minor updates and corrections.

2.02a 0 120514 OO Chapter "AutoIP" added.

Chapter "Address Collision Detection" added.

2.02 0 120507 OO

Documentation updated for embOS/IP V2 stack.

Chapter "API functions" updated.

* "IP_GetRawPacketInfo()" added.

* "IP_ICMP_Add()" added.

* "IP_TCP_Add()" added.

* "IP_UDP_Add()" added.

Chapter "PPP" added.

Chapter "NetBIOS" added.

1.60 0 100324 SK

Chapter "API functions" updated.

* "IP_SetSupportedDuplexModes()" added.

Chapter "FTP client" added.

Minor updates and corrections.

1.58 0 100204 SK

Chapter "SMTP client" updated.

Chapter "Configuration" updated.

* Section "Required buffers" updated.

Minor updates and corrections.

1.56 0 090710 SK

Chapter "API functions" updated.

* "IP_DNSC_SetMaxTLL()" added.

Chapter "Configuring embOS/IP" updated.

* Macro "IP_TCP_ACCEPT_CHECKSUM_FFFF" added.

1.54b 0 090603 SK

Chapter "Web server (Add-on)" updated.

* "IP_WEBS_Process()" updated.

* "IP_WEBS_ProcessLast()" added.

* "IP_WEBS_OnConnectionLimit()" updated.

1.54a 1 090520 SK

Chapter "API functions" updated.

* IP_GetAddrMask() updated.

* IP_GetGWMask() updated.

* IP_GetIPMask() updated.

Chapter "Web server (Add-on)" updated.

* Section "Changing the file system type" added.

* Section "IP_WEBS_SetFileInfoCallback" updated.

1.54a 0 090508 SK

Chapter "Web server (Add-on)" updated.

* IP_WEBS_GetNumParas() added.

* IP_WEBS_GetParaValue() added.

* IP_WEBS_DecodeAndCopyStr() added.

* IP_WEBS_DecodeString() added.

* IP_WEBS_SetFileInfoCallback() added.

* IP_WEBS_CompareFilenameExt() added.

* Section "Dynamic content" added

* Section "Common Gateway interface" moved into

section "Dynamic content".

Chapter "Socket interface"

* getpeername() corrected.

Chapter "Network interface drivers" updated.

1.54 0 090504 SK Chapter "UDP zero-copy" updated.

1.52 1 090402 SK Chapter "SMTP client" added.

1.52 0 090223 SK

Chapter "API functions":

* IP_SetTxBufferSize() added.

* IP_GetIPAddr() updated.

* IP_PrintIPAddr() updated.

1.50 0 081210 SK

Chapter "API functions":

* IP_ICMP_SetRxHook() added.

* IP_SetRxHook() added.

* IP_SOCKET_SetDefaultOptions() added.

* IP_SOCKET_SetLimit() added.

1.42 0 080821 SK

Chapter "Web server (Add-on)":

* List of valid values for CGI parameter and values

added.

Chapter "FTP Server (Add-on)":

* Section "FTP server system time" added.

* pfGetTimeDate() added.

1.40 0 080731 SK

Chapter "API functions":

* IP_TCP_SetConnKeepaliveOpt() added.

* IP_TCP_SetRetransDelayRange() added.

* IP_SendPacket() added.

Chapter "Socket interface":

* getsockopt() updated.

* setsockopt() updated.

Chapter "OS integration":

* IP_OS_WaitItemTimed() added.

1.30 1 080610 SK

Chapter "FTP server (Add-on)" section "Resource usage"

added

Chapter "Web server (Add-on)" section "Resource usage"

added

1.30 0 080423 SK Chapter "FTP server (Add-on)" added.

Chapter "Web server (Add-on)" updated.

1.24 3 080320 SK

Chapter "Socket interface":

* getpeername added.

* getsockname added.

1.24 2 080222 SK Chapter "Device Driver":

* NXP LPC23xx/24xx driver added.

1.24 1 080124 SK

Chapter "HTTP server (Add-on)" updated.

Chapter "API functions":

* IP_UTIL_EncodeBase64() added.

* IP_UTIL_DecodeBase64() added.

Software Revision Date By Description

1.24 0 080124 SK

Chapter "HTTP server (Add-on)" added:

Chapter "API functions":

* IP_AllowBackPressure() added.

* IP_GetIPAddr() added.

* IP_SendPing() added.

* IP_SetDefaultTTL() added.

1.22 4 071213 SK

Chapter "Introduction":

* Section "Components of an Ethernet system" added.

Chapter "API functions":

* IP_IsIFaceReady() added.

* IP_NI_ConfigPHYAddr() added.

* IP_NI_ConfigPHYMode() added.

* IP_NI_ConfigBasePtr () added.

Chapter "Socket interface":

* All functions: parameter description enhanced.

Chapter "Device drivers" renamed to "Network interface

drivers".

Chapter "Network interface drivers":

* Section "ATMEL AT91SAM7X" added.

* Section "ATMEL AT91SAM9260"added.

* Section "Davicom DM9000"added.

* Section "ST STR912"added.

1.22 3 071126 SK

Chapter "OS Integration":

* IP_OS_Sleep() removed.

* IP_OS_Wakeup() removed.

* IP_OS_WaitItem added.

* IP_OS_SignalItem added.

Chapter "Running embOS/IP on target hardware" updated.

1.22 2 071123 SK

Chapter "Socket interface":

* gethostbyname() added.

* Structure hostent added.

Chapter "Core functions":

* IP_PrintIPAddr() added.

* IP_DNS_SetServer() added.

1.22 1 071122 SK

Chapter "DHCP":

* IP_DHCPC_Activate() updated.

Chapter "Debugging":

* Section "Testing stability" added.

Chapter "Socket interface":

* Section "Error codes" added.

1.22 0 071114 SK

Chapter "Introduction":

* "Request for comments" enhanced.

Chapter "API functions":

* IP_AddLogFilter() added.

* IP_AddWarnFilter() added.

* IP_GetCurrentLinkSpeed() added.

* IP_TCP_Set2MSLDelay() added.

* select() added.

Various function descriptions enhanced.

Chapter "API functions" renamed to "core functions".

Socket functions removed from chapter "API functions"

Chapter "Socket interface" added.

Chapter "DHCP" added.

Chapter "UDP zero copy" added.

Chapter "TCP zero copy" added.

Chapter "Glossary" added.

Chapter "Index" updated.

Software Revision Date By Description

1.00 2 071017 SK

Chapter "Introduction":

* Section "Features" enhanced.

* Section "Basic concepts" added.

* Section "Task and interrupt usage" added.

* Section "Further readings" added.

Chapter "Running embOS/IP" enhanced.

Chapter "API functions":

* IP_Init() added.

* IP_Task() added.

* IP_RxTask() added.

* IP_GetVersion() added.

* IP_SetLogFilter() added.

* IP_SetWarnFilter() added.

* IP_Panic() removed.

* Structure sockaddr added.

* Structure sockaddr_in added.

* Structure in_addr added.

Chapter "Device driver".

* General information updated.

* Section "Writing your own driver" added.

Chapter "Debugging" added.

Chapter "Performance and resource usage" added.

Chapter "OS integration" updated.

1.00 1 071002 SK

Product name changed to "embOS/IP":

Chapter "API functions":

* IP_X_Prepare() renamed to IP_X_Config().

* IP_AddBuffers() added.

* IP_ConfTCPSpace() added.

1.00 0 070927 SK Initial version.

Software Revision Date By Description

About this document

Assumptions

This document assumes that you already have a solid knowledge of the following:

• The software tools used for building your application (assembler, linker, C com-

piler)

• The C programming language

• The target processor

• DOS command line

If you feel that your knowledge of C is not sufficient, we recommend The C Program-

ming Language by Kernighan and Richie (ISBN 0-13-1103628), which describes the

standard in C-programming and, in newer editions, also covers the ANSI C standard.

How to use this manual

This manual explains all the functions and macros that the product offers. It assumes

you have a working knowledge of the C language. Knowledge of assembly program-

ming is not required.

Typographic conventions for syntax

This manual uses the following typographic conventions:

Style Used for

Body Body text.

Keyword Text that you enter at the command-prompt or that appears on the

display (that is system functions, file- or pathnames).

Parameter Parameters in API functions.

Sample Sample code in program examples.

Sample comment Comments in programm examples.

Reference Reference to chapters, sections, tables and figures or other docu-

ments.

GUIElement Buttons, dialog boxes, menu names, menu commands.

Emphasis Very important sections.

Table 1.1:

EMBEDDED SOFTWARE

(Middleware)

emWin

Graphics software and GUI

emWin is designed to provide an effi-

cient, processor- and display control-

ler-independent graphical user

interface (GUI) for any application that

operates with a graphical display.

embOS

Real Time Operating System

embOS is an RTOS designed to offer

the benefits of a complete multitasking

system for hard real time applications

with minimal resources.

embOS/IP

TCP/IP stack

embOS/IP a high-performance TCP/IP

stack that has been optimized for

speed, versatility and a small memory

footprint.

emFile

File system

emFile is an embedded file system with

FAT12, FAT16 and FAT32 support. Var-

ious Device drivers, e.g. for NAND and

NOR flashes, SD/MMC and Compact-

Flash cards, are available.

USB-Stack

USB device/host stack

A USB stack designed to work on any

embedded system with a USB control-

ler. Bulk communication and most stan-

dard device classes are supported.

SEGGER TOOLS

Flasher

Flash programmer

Flash Programming tool primarily for micro con-

trollers.

J-Link

JTAG emulator for ARM cores

USB driven JTAG interface for ARM cores.

J-Trace

JTAG emulator with trace

USB driven JTAG interface for ARM cores with

Trace memory. supporting the ARM ETM (Embed-

ded Trace Macrocell).

J-Link / J-Trace Related Software

Add-on software to be used with SEGGER’s indus-

try standard JTAG emulator, this includes flash

programming software and flash breakpoints.

SEGGER Microcontroller GmbH & Co. KG develops

and distributes software development tools and ANSI C

software components (middleware) for embedded sys-

tems in several industries such as telecom, medical

technology, consumer electronics, automotive industry

and industrial automation.

SEGGER’s intention is to cut software development time

for embedded applications by offering compact flexible and easy to use middleware,

allowing developers to concentrate on their application.

Our most popular products are emWin, a universal graphic software package for embed-

ded applications, and embOS, a small yet efficient real-time kernel. emWin, written

entirely in ANSI C, can easily be used on any CPU and most any display. It is comple-

mented by the available PC tools: Bitmap Converter, Font Converter, Simulator and

Viewer. embOS supports most 8/16/32-bit CPUs. Its small memory footprint makes it

suitable for single-chip applications.

Apart from its main focus on software tools, SEGGER develops and produces programming

tools for flash micro controllers, as well as J-Link, a JTAG emulator to assist in develop-

ment, debugging and production, which has rapidly become the industry standard for

debug access to ARM cores.

Corporate Office:

http://www.segger.com

United States Office:

http://www.segger-us.com

UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
9
 Introduction to embOS/IP...............................................................................................15
1 What is embOS/IP ...................................................................................16
2 Features.................................................................................................16
3 Basic concepts ........................................................................................ 17
3.1 embOS/IP structure .................................................................................17
3.2 Encapsulation..........................................................................................18
4 Tasks and interrupt usage.........................................................................19
5 Background information ...........................................................................22
5.1 Components of an Ethernet system............................................................22
6 Further reading ....................................................................................... 25
6.1 Request for Comments (RFC) ....................................................................25
6.2 Related books ......................................................................................... 26
7 Development environment (compiler)......................................................... 27
 Running embOS/IP on target hardware.........................................................................29
1 Step 1: Open an embOS start project.........................................................31
2 Step 2: Adding embOS/IP to the start project.............................................. 32
3 Step 3: Build the project and test it ........................................................... 34
 Example applications.....................................................................................................35
1 Overview................................................................................................36
1.1 embOS/IP DNS client (OS_IP_DNSClient.c) .................................................37
1.2 embOS/IP non-blocking connect (OS_IP_NonBlockingConnect.c)....................37
1.3 embOS/IP ping (OS_IP_Ping.c).................................................................. 37
1.4 embOS/IP shell (OS_IP_Shell.c) ................................................................37
1.5 embOS/IP simple server (OS_IP_SimpleServer.c) ........................................38
1.6 embOS/IP speed client (OS_IP_SpeedClient_TCP.c) .....................................38
1.7 embOS/IP start (OS_IP_Start.c) ................................................................39
1.8 embOS/IP UDP discover (OS_IP_UDPDiscover.c / OS_IP_UDPDiscoverZeroCopy.c)
39
 Core functions................................................................................................................41
1 API functions ..........................................................................................42
2 Configuration functions.............................................................................44
3 Management functions ............................................................................. 77
4 Network interface configuration and handling functions................................. 83
5 Other IP stack functions ...........................................................................89
6 Stack internal functions, variables and data-structures ............................... 107
 Socket interface...........................................................................................................109
1 API functions ........................................................................................ 110
2 Socket data structures ........................................................................... 137
3 Error codes ........................................................................................... 141
 TCP zero-copy interface..............................................................................................143
1 TCP zero-copy....................................................................................... 144
1.1 Allocating, freeing and sending packet buffers ........................................... 144
1.2 Callback function ................................................................................... 144
2 Sending data with the TCP zero-copy API.................................................. 145
Table of Contents

10
UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
2.1 Allocating a packet buffer ........................................................................145
2.2 Filling the allocated buffer with data .........................................................145
2.3 Sending the packet.................................................................................145
3 Receiving data with the TCP zero-copy API ................................................146
3.1 Writing a callback function.......................................................................146
3.2 Registering the callback function ..............................................................146
4 API functions .........................................................................................147
 UDP zero-copy interface..............................................................................................153
1 UDP zero-copy .......................................................................................154
1.1 Allocating, freeing and sending packet buffers............................................154
1.2 Callback function....................................................................................154
2 Sending data with the UDP zero-copy API..................................................155
2.1 Allocating a packet buffer ........................................................................155
2.2 Filling the allocated buffer with data .........................................................155
2.3 Sending the packet.................................................................................155
3 Receiving data with the UDP zero-copy API................................................156
3.1 Writing a callback function.......................................................................156
3.2 Registering the callback function ..............................................................156
4 API functions .........................................................................................157
 DHCP client .................................................................................................................169
1 DHCP backgrounds .................................................................................170
2 API functions .........................................................................................171
 AutoIP..........................................................................................................................177
1 embOS/IP AutoIP backgrounds ................................................................178
2 API functions .........................................................................................179
3 AutoIP resource usage ............................................................................184
3.1 ROM usage on an ARM7 system ...............................................................184
3.2 ROM usage on a Cortex-M3 system ..........................................................184
3.3 RAM usage ............................................................................................184
 Address Collision Detection.......................................................................................185
1 embOS/IP ACD backgrounds....................................................................186
2 API functions .........................................................................................187
3 ACD data structures ...............................................................................190
4 ACD resource usage ...............................................................................191
4.1 ROM usage on an ARM7 system ...............................................................191
4.2 ROM usage on a Cortex-M3 system ..........................................................191
4.3 RAM usage ............................................................................................191
 UPnP (Add-on)...........................................................................................................193
1 embOS/IP UPnP .....................................................................................194
2 Feature list............................................................................................195
3 Requirements ........................................................................................196
4 UPnP backgrounds..................................................................................197
4.1 Using UPnP to advertise your service in the network ...................................197
5 API functions .........................................................................................205
6 UPnP resource usage ..............................................................................207
6.1 ROM usage on an ARM7 system ...............................................................207
6.2 ROM usage on a Cortex-M3 system ..........................................................207
6.3 RAM usage ............................................................................................207
 VLAN..........................................................................................................................209
1 embOS/IP VLAN.....................................................................................210
2 Feature list............................................................................................211
3 VLAN backgrounds .................................................................................212
4 API functions .........................................................................................213

UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
11
5 VLAN resource usage ............................................................................. 215
5.1 ROM usage on an ARM7 system............................................................... 215
5.2 ROM usage on a Cortex-M3 system.......................................................... 215
5.3 RAM usage ........................................................................................... 215
 Network interface drivers...........................................................................................217
1 General information ............................................................................... 218
1.1 MAC address filtering ............................................................................. 218
1.2 Checksum computation in hardware ......................................................... 218
1.3 Ethernet CRC computation ...................................................................... 218
2 Available network interface drivers........................................................... 219
2.1 ATMEL AT91CAP9 .................................................................................. 220
2.2 ATMEL AT91RM9200 .............................................................................. 225
2.3 ATMEL AT91SAM7X................................................................................ 229
2.4 ATMEL AT91SAM9260 ............................................................................ 233
2.5 DAVICOM DM9000/DM9000A .................................................................. 236
2.6 FREESCALE ColdFire MCF5329................................................................. 239
2.7 NXP LPC17xx ........................................................................................ 242
2.8 NXP LPC23xx / 24xx .............................................................................. 244
2.9 ST STR912 ........................................................................................... 246
3 Writing your own driver.......................................................................... 248
3.1 Device driver functions........................................................................... 250
 Configuring embOS/IP...............................................................................................255
1 Runtime configuration ............................................................................ 256
1.1 IP_X_Configure()................................................................................... 256
1.2 Driver handling ..................................................................................... 257
1.3 Memory and buffer assignment................................................................ 257
2 Compile-time configuration ..................................................................... 259
2.1 Compile-time configuration switches ........................................................ 259
2.2 Debug level .......................................................................................... 260
 Web server (Add-on)..................................................................................................261
1 embOS/IP web server ............................................................................ 262
2 Feature list ........................................................................................... 263
3 Requirements........................................................................................ 264
4 HTTP backgrounds ................................................................................. 265
4.1 HTTP communication basics .................................................................... 265
4.2 HTTP status codes ................................................................................. 266
5 Using the web server sample................................................................... 267
5.1 Using the Windows sample...................................................................... 268
5.2 Running the web server example on target hardware ................................. 268
5.3 Changing the file system type ................................................................. 269
6 Dynamic content ................................................................................... 270
6.1 Common Gateway Interface (CGI) ........................................................... 270
6.2 Virtual files ........................................................................................... 272
7 Authentication....................................................................................... 274
7.1 Authentication example .......................................................................... 275
7.2 Configuration of the authentication .......................................................... 276
8 Form handling....................................................................................... 277
8.1 Simple form processing sample ............................................................... 278
9 File upload............................................................................................ 281
9.1 Simple form upload sample..................................................................... 281
10 Configuration ........................................................................................ 283
10.1 Compile time configuration switches......................................................... 283
11 API functions ........................................................................................ 286
12 Web server data structures ..................................................................... 311
13 Resource usage ..................................................................................... 319
13.1 ROM usage on an ARM7 system............................................................... 319
13.2 ROM usage on a Cortex-M3 system .......................................................... 319

12
UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
13.3 RAM usage:...........................................................................................319
 SMTP client (Add-on).................................................................................................321
1 embOS/IP SMTP client ............................................................................322
2 Feature list............................................................................................323
3 Requirements ........................................................................................324
4 SMTP backgrounds .................................................................................325
5 Configuration.........................................................................................327
5.1 Compile time configuration switches .........................................................327
6 API functions .........................................................................................328
7 SMTP client data structures .....................................................................330
8 Resource usage .....................................................................................338
8.1 Resource usage on an ARM7 system .........................................................338
8.2 Resource usage on a Cortex-M3 system ....................................................338
 FTP server (Add-on)..................................................................................................339
1 embOS/IP FTP server..............................................................................340
2 Feature list............................................................................................341
3 Requirements ........................................................................................342
4 FTP basics .............................................................................................343
4.1 Active mode FTP ....................................................................................344
4.2 Passive mode FTP ..................................................................................345
4.3 FTP reply codes......................................................................................346
4.4 Supported FTP commands .......................................................................347
5 Using the FTP server sample....................................................................348
5.1 Using the Windows sample ......................................................................348
5.2 Running the FTP server example on target hardware...................................348
6 Access control........................................................................................349
7 Configuration.........................................................................................355
7.1 Compile time configuration switches .........................................................355
7.2 FTP server system time...........................................................................356
8 API functions .........................................................................................358
9 FTP server data structures.......................................................................361
10 Resource usage .....................................................................................364
10.1 ROM usage on an ARM7 system ...............................................................364
10.2 ROM usage on a Cortex-M3 system ..........................................................364
10.3 RAM usage:...........................................................................................364
 FTP client (Add-on)....................................................................................................365
1 embOS/IP FTP client...............................................................................366
2 Feature list............................................................................................367
3 Requirements ........................................................................................368
4 FTP basics .............................................................................................369
4.1 Passive mode FTP ..................................................................................370
4.2 Supported FTP client commands...............................................................371
5 Configuration.........................................................................................372
5.1 Compile time configuration switches .........................................................372
6 API functions .........................................................................................373
7 FTP client data structures ........................................................................381
8 Resource usage .....................................................................................382
8.1 ROM usage on an ARM7 system ...............................................................382
8.2 ROM usage on a Cortex-M3 system ..........................................................382
8.3 RAM usage:...........................................................................................382
 PPP / PPPoE (Add-on)..............................................................................................383
1 embOS/IP PPP/PPPoE..............................................................................384
2 Feature list............................................................................................385
3 Requirements ........................................................................................386
4 PPP backgrounds....................................................................................387

UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
13
5 API functions ........................................................................................ 388
6 PPPoE functions..................................................................................... 389
7 PPP functions ........................................................................................ 395
8 Modem functions ................................................................................... 401
9 PPP data structures................................................................................ 413
10 PPPoE resource usage ............................................................................ 419
10.1 ROM usage on an ARM7 system............................................................... 419
10.2 ROM usage on a Cortex-M3 system .......................................................... 419
10.3 RAM usage ........................................................................................... 419
11 PPP resource usage................................................................................ 420
 NetBIOS (Add-on)......................................................................................................421
1 embOS/IP NetBIOS................................................................................ 422
2 Feature list ........................................................................................... 423
3 Requirements........................................................................................ 424
4 NetBIOS backgrounds ............................................................................ 425
5 API functions ........................................................................................ 426
6 Resource usage ..................................................................................... 431
6.1 ROM usage on an ARM7 system............................................................... 431
6.2 ROM usage on a Cortex-M3 system.......................................................... 431
6.3 RAM usage ........................................................................................... 431
 Debugging..................................................................................................................433
1 Message output..................................................................................... 434
2 Testing stability ..................................................................................... 435
3 API functions ........................................................................................ 436
4 Message types ...................................................................................... 442
5 Using a network sniffer to analyse communication problems........................ 444
 OS integration............................................................................................................445
1 General information ............................................................................... 446
2 OS layer API functions............................................................................ 447
2.1 Examples ............................................................................................. 447
 Performance & resource usage.................................................................................449
1 Memory footprint................................................................................... 450
1.1 ARM7 system ........................................................................................ 450
1.2 Cortex-M3 system ................................................................................. 451
2 Performance ......................................................................................... 452
2.1 ARM7 system ........................................................................................ 452
2.2 Cortex-M3 system ................................................................................. 453
 Appendix A - File system abstraction layer................................................................455
1 File system abstraction layer ................................................................... 456
2 File system abstraction layer function table ............................................... 457
2.1 emFile interface..................................................................................... 459
2.2 Read-only file system............................................................................. 460
2.3 Using the read-only file system ............................................................... 460
2.4 Windows file system interface ................................................................. 462
 Glossary.....................................................................................................................463

Chapter 1

Introduction to embOS/IP

This chapter provides an introduction to using embOS/IP. It explains the basic con-

cepts behind embOS/IP.

16 CHAPTER 1 Introduction to embOS/IP

1.1 What is embOS/IP

embOS/IP is a CPU-independent TCP/IP stack.

embOS/IP is a high-performance library that has been optimized for speed, versatil-

ity and small memory footprint.

1.2 Features

embOS/IP is written in ANSI C and can be used on virtually any CPU.

Some features of embOS/IP:

• Standard socket interface.

• High performance.

• Small footprint.

• No configuration required.

•Runs “out-of-the-box”.

• Very simple network interface driver structure.

• Works seamlessly with embOS in multitasking environment.

• Zero data copy for ultra fast performance.

• Non-blocking versions of all functions.

• Connections limited only by memory availability.

• Delayed ACKs.

• Handling gratuitous ARP packets

• Support for VLAN

• BSD style “keep-alive” option.

• Support for messages and warnings in debug build.

• Drivers for most common Ethernet controllers available.

• Support for driver side (hardware) checksum computation.

•Royalty-free.

1.3 Basic concepts

1.3.1 embOS/IP structure

embOS/IP is organized in different layers, as shown in the following illustration.

A short description of each layer’s functionality follows below.

Application layer

The application layer is the interface between embOS/IP and the user application. It

uses the embOS/IP API to transmit data over an TCP/IP network. The embOS/IP API

provides functions in BSD (Berkeley Software Distribution) socket style, such as con-

nect(), bind(), listen(), etc.

Transport layer

The transport layer provides end-to-end communication services for applications. The

two relevant protocols of the Transport layer protocol are the Transmission Control

Protocol (TCP) and the User Datagram Protocol (UDP). TCP is a reliable connection-

oriented transport service. It provides end-to-end reliability, resequencing, and flow

control. UDP is a connectionless transport service.

Internet layer

All protocols of the transport layer use the Internet Protocol (IP) to carry data from

source host to destination host. IP is a connectionless service, providing no end-to-

end delivery guarantees. IP datagrams may arrive at the destination host damaged,

duplicated, out of order, or not at all. The transport layer is responsible for reliable

delivery of the datagrams when it is required. The IP protocol includes provision for

addressing, type-of-service specification, fragmentation and reassembly, and secu-

rity information.

Link layer

The link layer provides the implementation of the communication protocol used to

interface to the directly-connected network. A variety of communication protocols

have been developed and standardized. The most commonly used protocol is Ether-

net (IEEE 802.3). In this version of embOS/IP only Ethernet is supported.

Application layer

Transport layer

Network layer

Link layer

DHCP, DNS, FTP, HTTP, POP3,

SMTP, TELNET, SSL, ...

TCP / UDP

IP, ICMP, IGMP, ARP, RARP, ...

Ethernet (IEEE 802.3), ...

18 CHAPTER 1 Introduction to embOS/IP

1.3.2 Encapsulation

The four layers structure is defined in [RFC 1122]. The data flow starts at the appli-

cation layer and goes over the transport layer, the network layer, and the link layer.

Every protocol adds an protocol-specific header and encapsulates the data and

header from the layer above as data. On the receiving side, the data will be extracted

in the complementary direction. The opposed protocols do not know which protocol

on the above and below layers are used.

The following illustration shows the encapsulation of data within an UDP datagram

within an IP packet.

Application

layer

Transport

layer

Network

layer

Link

layer

Data

UDP data

UDP

header

header IP data

Frame

header

Frame

footer

Frame data

1.4 Tasks and interrupt usage

embOS/IP can be used in an application in three different ways.

• One task dedicated to the stack (IP_Task)

• Two tasks dedicated to the stack (IP_Task, IP_RxTask)

• Zero tasks dedicated to the stack (Superloop)

The default task structure is one task dedicated to the stack. The priority of the man-

agement tasks IP_Task (and IP_RxTask if available) should be higher then the prior-

ity of an application task which uses the stack.

One task dedicated to the stack

To use one task dedicated to the stack is the simplest way to use the TCP/IP stack. It

is called IP_Task and handles housekeeping operations, resending and handling of

incoming packets. The “Read packet” operation is performed from within the ISR.

Because the “Read packet” operation is called directly from the ISR, no additional

task is required. The length of the interrupt latency will be extended for the time

period which is required to process the “Read packet” operation. Refer to IP_Task()

on page 80 for more information and an example about how to include the IP_Task

into your embOS project.

...

Task

Routine / Action

Interrupt (ISR) embOS/IP

IP_Exec() Read

packet

IP_OnRx()

IP_Task

App.

task n

App.

task 1

IP stack

IP stack / Driver

Application tasks

20 CHAPTER 1 Introduction to embOS/IP

Two tasks dedicated to the stack

Two tasks are dedicated to the stack. The first task is called the IP_Task and handles

housekeeping operations, resends, and handling of incoming packets. The second is

called IP_RxTask and handles the “Read packet” operation. IP_RxTask is waked up

from the interrupt service routine, if new packets are available. The interrupt latency

is not extended, because the “Read packet” operation has been moved from the

interrupt service routine to IP_RxTask. Refer to IP_Task() on page 80 and

IP_RxTask() on page 81 for more information.

...

Task

Routine / Action

Interrupt (ISR) embOS/IP

IP_Exec() Read

packet

IP_OnRx()

IP_RxTask

IP_Task

App.

task n

App.

task 1

IP stack

IP stack / Driver

Application tasks

Zero tasks dedicated to the stack (Superloop)

embOS/IP can also be used without any additional task for the stack, if an application

task calls IP_Exec() periodically. The “Read packet” operation is performed from

within the ISR. Because the “Read packet” operation is called directly from the ISR,

no additional task is required. The length of the interrupt latency will be extended for

the time period which is required to process the “Read packet” operation.

...

Task

Routine / Action

Interrupt (ISR) embOS/IP

IP_Exec() Read

packet

IP_OnRx()

App.

task n

App.

task 1

IP stack

IP stack / Driver

Application tasks

22 CHAPTER 1 Introduction to embOS/IP

1.5 Background information

1.5.1 Components of an Ethernet system

Main parts of an Ethernet system are the Media Access Controller (MAC) and the

Physical device (PHY). The MAC handles generating and parsing physical frames and

the PHY handles how this data is actually moved to or from the wire.

MCUs with integrated MAC

Some modern MCUs (for example, the ATMEL SAM7X or the ST STR912) include the

MAC and use the internal RAM to store the Ethernet data. The following block dia-

gram illustrates such a configuration.

External Ethernet controllers with MAC and PHY

Chips without integrated MAC can use fully integrated single chip Ethernet MAC con-

troller with integrated PHY and a general processor interface. The following sche-

matic illustrates such a configuration.

PHY

CPU

RAM

Connector

MAC

PHY

CPU

RAM

Connector

MAC

1.5.1.1 MII / RMII: Interface between MAC and PHY

The MAC communicates with the PHY via the Media Independent Interface (MII) or

the Reduced Media Independent Interface (RMII). The MII is defined in IEEE 802.3u.

The RMII is a subset of the MII and is defined in the RMI specification. The MII/RMII

can handle control over the PHY which allows for selection of such transmission crite-

ria as line speed, duplex mode, etc.

In theory, up to 32 PHYs can be connected to a single MAC. In praxis, this is never

done; only one PHY is connected. In order to allow multiple PHYs to be connected to

a single MAC, individual 5-bit addresses have to be assigned to the different PHYs. If

only one PHY is connected, the embOS/IP driver automatically finds the address of it.

The standard defines 32 16-bit PHY registers. The first 6 are defined by the standard.

The drivers automatically recognize any PHY connected, no manual configuration of

PHY address is required.

The MII and RMII interface are capable of both 10Mb/s and 100Mb/s data rates as

described in the IEEE 802.3u standard.

The intent of the RMII is to provide a reduced pin count alternative to the IEEE

802.3u MII. It uses 2 bits for transmit (TXD0 and TXD1) and two bits for receive

(RXD0 and RXD1). There is a Transmit Enable (TX_EN), a Receive Error (RX_ER), a

Carrier Sense (CRS), and a 50 MHz Reference Clock (TX_CLK) for 100Mb/s data rate.

The pins used by the MII and RMII interfaces are described in the following table.

BMCR Basic Mode Control Register

BSR Basic Mode Status Register

PHYSID1 PHYS ID 1

PHYSID2 PHYS ID 2

ANAR Auto-Negotiation Advertisement Register

LPAR Link Partner Ability register

Table 1.1: Standardized registers of the MAC/PHY interface

Signal MII RMII

TX_CLK Transmit Clock (25 MHz) Reference Clock (50 MHz)

TX_EN Transmit Enable Transmit Enable

TXD[0:1] 4-bit Transmit Data 2-bit Transmit Data

TXD[2:3] N/A

PHYCLK PHY Clock Output PHY Clock Output

Table 1.2: MII / RMII comparison

MAC PHY

TXD 0-1

TXD 2-3

TX_CLK

TX_EN

PHYCLK

CRS

COL

MDIO

MDC

RX_CLK

RX_DV

RX_ER

RXD 0-1

RXD 2-3

24 CHAPTER 1 Introduction to embOS/IP

CRS Carrier Sense N/A

COL Collision Detect N/A

MDIO Management data I/O Management data I/O

MDC Data Transfer Timing Reference

Clock

Data Transfer Timing Reference

Clock

RX_CLK Receive Clock N/A

RXD[0:1] 4-bit Receive Data 2-bit Receive Data

RXD[2:3] N/A

RX_DV Data Valid Carrier Sense/Data Valid

RX_ER Receive Error Receive Error

Signal MII RMII

Table 1.2: MII / RMII comparison

1.6 Further reading

This guide explains the usage of the embOS/IP protocol stack. It describes all func-

tions which are required to build a network application. For a deeper understanding

about how the protocols of the internet protocol suite works use the following refer-

ences.

The following Request for Comments (RFC) define the relevant protocols of the inter-

net protocol suite and have been used to build the protocol stack. They contain all

required technical specifications. The listed books are simpler to read as the RFCs

and give a general survey about the interconnection of the different protocols.

1.6.1 Request for Comments (RFC)

RFC# Description

[RFC 768] UDP - User Datagram Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc768.txt

[RFC 791] IP - Internet Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc791.txt

[RFC 792] ICMP - Internet Control Message Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc792.txt

[RFC 793] TCP - Transmission Control Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc793.txt

[RFC 821] SMTP - Simple Mail Transfer Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc826.txt

[RFC 826] ARP - Ethernet Address Resolution Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc826.txt

[RFC 951] BOOTP - Bootstrap Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc951.txt

[RFC 959] FTP - File Transfer Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc959.txt

[RFC 1034] DNS - Domain names - concepts and facilities

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1034.txt

[RFC 1035] DNS - Domain names - implementation and specification

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1035.txt

[RFC 1042] IE-EEE - Transmission of IP datagrams over IEEE 802 networks

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1042.txt

[RFC 1122] Requirements for Internet Hosts - Communication Layers

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1122.txt

[RFC 1123] Requirements for Internet Hosts - Application and Support

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1123.txt

[RFC 1661] PPP - Point-to-Point Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1661.txt

[RFC 1939] POP3 - Post Office Protocol - Version 3

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1939.txt

[RFC 2131] DHCP - Dynamic Host Configuration Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc2131.txt

[RFC 2616] HTTP - Hypertext Transfer Protocol -- HTTP/1.1

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc2616.txt

26 CHAPTER 1 Introduction to embOS/IP

1.6.2 Related books

• [Comer] - Computer Networks and Internets, Douglas E Comer and Ralph E.

Droms - ISBN: 978-0131433519

• [Tannenbaum] - Computer Networks, Andrew S. Tannenbaum

ISBN: 978-0130661029

• [StevensV1] - TCP/IP Illustrated, Volume 1, W. Richard Stevens

ISBN: 978-0201633467.

• [StevensV2] - TCP/IP Illustrated, Volume 2, W. Richard Stevens and Gary R.

Wright - ISBN: 978-0201633542.

• [StevensV3] - TCP/IP Illustrated, Volume 3, W. Richard Stevens

ISBN: 978-0201634952.

1.7 Development environment (compiler)

The CPU used is of no importance; only an ANSI-compliant C compiler complying with

at least one of the following international standard is required:

• ISO/IEC/ANSI 9899:1990 (C90) with support for C++ style comments (//)

• ISO/IEC 9899:1999 (C99)

• ISO/IEC 14882:1998 (C++)

If your compiler has some limitations, let us know and we will inform you if these will

be a problem when compiling the software. Any compiler for 16/32/64-bit CPUs or

DSPs that we know of can be used; most 8-bit compilers can be used as well.

A C++ compiler is not required, but can be used. The application program can there-

fore also be programmed in C++ if desired.

28 CHAPTER 1 Introduction to embOS/IP

Chapter 2

Running embOS/IP on target

hardware

This chapter explains how to integrate and run embOS/IP on your target hardware.

It explains this process step-by-step.

30 CHAPTER 2 Running embOS/IP on target hardware

Integrating embOS/IP

The embOS/IP default configuration is preconfigured with valid values, which

matches the requirements of the most applications. embOS/IP is designed to be used

with embOS, SEGGER’s real-time operating system. We recommend to start with an

embOS sample project and include embOS/IP into this project.

We assume that you are familiar with the tools you have selected for your project

(compiler, project manager, linker, etc.). You should therefore be able to add files,

add directories to the include search path, and so on. In this document the IAR

Embedded Workbench® IDE is used for all examples and screenshots, but every other

ANSI C toolchain can also be used. It is also possible to use make files; in this case,

when we say “add to the project”, this translates into “add to the make file”.

Procedure to follow

Integration of embOS/IP is a relatively simple process, which consists of the follow-

ing steps:

• Step 1: Open an embOS project and compile it.

• Step 2: Add embOS/IP to the start project

• Step 3: Compile the project

2.1 Step 1: Open an embOS start project

We recommend that you use one of the supplied embOS start projects for your target

system. Compile the project and run it on your target hardware.

32 CHAPTER 2 Running embOS/IP on target hardware

2.2 Step 2: Adding embOS/IP to the start project

Add all source files in the following directory to your project:

• Config

•IP

• UTIL (optional)

The Config folder includes all configuration files of embOS/IP. The configuration files

are preconfigured with valid values, which match the requirements of most applica-

tions. Add the hardware configuration IP_Config_<TargetName>.c supplied with the

driver shipment.

If your hardware is currently not supported, use the example configuration file and

the driver template to write your own driver. The example configuration file and the

driver template is located in the Sample\Driver\Template folder.

The Util folder is an optional component of the embOS/IP shipment. It contains

optimized MCU and/or compiler specific files, for example a special memcopy func-

tion.

Replace BSP.c and BSP.h of your embOS start project

Replace the BSP.c source file and the BSP.h header file used in your embOS start

project with the one which is supplied with the embOS/IP shipment. Some drivers

require a special functions which initializes the network interface of the driver. This

function is called BSP_ETH_Init(). It is used to enable the ports which are connected

to the network hardware. All network interface driver packages include the BSP.c

and BSP.h files irrespective if the BSP_ETH_Init() function is implemented.

Configuring the include path

The include path is the path in which the compiler looks for include files. In cases

where the included files (typically header files, .h) do not reside in the same direc-

tory as the C file to compile, an include path needs to be set. In order to build the

project with all added files, you will need to add the following directories to your

include path:

• Config

• Inc

•IP

Select the start application

For quick and easy testing of your embOS/IP integration, start with the code found in

the folder Application. Add one of the applications to your project (for example

OS_IP_SimpleServer.c).

34 CHAPTER 2 Running embOS/IP on target hardware

2.3 Step 3: Build the project and test it

Build the project. It should compile without errors and warnings. If you encounter

any problem during the build process, check your include path and your project con-

figuration settings. To test the project, download the output into your target and

start the application.

By default, ICMP is activated. This means that you could ping your target. Open the

command line interface of your operating system and enter ping <TargetAddress>,

to check if the stack runs on your target. The target should answer all pings without

any error.

Chapter 3

Example applications

In this chapter, you will find a description of each embOS/IP example application.

36 CHAPTER 3 Example applications

3.1 Overview

Various example applications for embOS/IP are supplied. These can be used for test-

ing the correct installation and proper function of the device running embOS/IP.

The following start application files are provided:

The example applications for the target-side are supplied in source code in the

Application directory.

File Description

OS_IP_DNSClient.c Demonstrates the use of the integrated DNS cli-

ent.

OS_IP_NonBlockingConnect.c Demonstrates how to connect to a server using

non-blocking sockets.

OS_IP_Ping.c Demonstrates how to send ICMP echo requests

and how to process ICMP replies in application.

OS_IP_Shell.c Demonstrates using the IP-shell to diagnose the

IP stack.

OS_IP_SimpleServer.c

Demonstrates setup of a simple server which

simply sends back the target system tick for

every character received.

OS_IP_SpeedClient_TCP.c

Demonstrates the TCP send and receive perfor-

mance of the device running embOS/IP. Refer to

embOS/IP speed client

(OS_IP_SpeedClient_TCP.c) on page 38 for

detailed information.

OS_IP_Start.c

Demonstrates use of the IP stack without any

server or client program. To ping the target, use

the command line: ping <target-ip> where

<target-ip> represents the IP address of the

target, which depends on the configuration and

is usually 192.168.5.1 if the DHCP client is not

enabled.

OS_IP_UDPDiscover.c

Demonstrates setup of a simple UDP application

which replies to UDP broadcasts. The application

sends an answer for every received discover

packet. The related host application sends dis-

cover packets as UDP broadcasts and waits for

the feedback of the targets which are available

in the subnet.

OS_IP_UDPDiscoverZeroCopy.c

Demonstrates setup of a simple UDP application

which replies to UDP broadcasts. The application

uses the the embOS/IP zero-copy interface. It

sends an answer for every received discover

packet. The related host application sends dis-

cover packets as UDP broadcasts and waits for

the feedback of the targets which are available

in the subnet.

Table 3.1: embOS/IP example applications

3.1.1 embOS/IP DNS client (OS_IP_DNSClient.c)

The embOS/IP DNS client resolves a hostname (for example, segger.com) to an IP

address and outputs the resolved address via terminal I/O.

3.1.2 embOS/IP non-blocking connect

(OS_IP_NonBlockingConnect.c)

The embOS/IP non-blocking connect sample demonstrates how to connect to a

server using non-blocking sockets. The target tries to connect to TCP server with an

non-blocking socket. The sample can be used with any TCP server independent of the

application which is listening on the port. The client only opens a TCP connection to

the server and closes it without any further communication. The terminal I/O output

in your debugger should be similar to the following out:

Connecting using non-blocking socket...

Successfully connected after 2ms!

1 of 1 tries were successful.

Connecting using non-blocking socket...

Successfully connected after 1ms!

2 of 2 tries were successful.

3.1.3 embOS/IP ping (OS_IP_Ping.c)

The embOS/IP ping sample demonstrates how to send ICMP echo requests and how

to process received ICMP packets in your application. A callback function is imple-

mented which outputs a message if an ICMP echo reply or an ICMP echo request has

been received.

To test the embOS/IP ICMP implementation, you have to perform the following steps:

1. Customize the Local defines, configurable section of OS_IP_Ping.c.

Change the macro HOST_TO_PING accordant to your configuration. For example, if

the Windows host PC which you want to ping use the IP address 192.168.5.15,

change the HOST_TO_PING macro to 0xC0A8050F.

2. Open the command line interface and enter:

ping [IP_ADDRESS _OF_YOUR_TARGET_RUNNING_EMBOSIP]

The terminal I/O output in your debugger should be similar to the following out:

ICMP echo reply received!

ICMP echo request received!

ICMP echo reply received!

ICMP echo request received!

ICMP echo reply received!

3.1.4 embOS/IP shell (OS_IP_Shell.c)

The embOS/IP shell server is a task which opens TCP-port 23 (telnet) and waits for a

connection. The actual shell server is part of the stack, which keep the application

program nice and small. The shell server task can be added to any application and

should be used to retrieve status information while the target is running. To connect

38 CHAPTER 3 Example applications

to the target, use the command line: telnet <target-ip> where <target-ip> rep-

resents the IP address of the target, which depends on the configuration and is usu-

ally 192.168.5.230 if the DHCP client is not enabled.

3.1.5 embOS/IP simple server (OS_IP_SimpleServer.c)

Demonstrates setup of a simple server which simply sends back the target system

tick for every character received. It opens TCP-port 23 (telnet) and waits for a con-

nection. To connect to the target, use the command line: telnet <target-ip>

where <target-ip> represents the IP address of the target, which depends on the

configuration and is usually 192.168.5.230 if the DHCP client is not enabled.

3.1.6 embOS/IP speed client (OS_IP_SpeedClient_TCP.c)

The embOS/IP speed client is a small application to detect the TCP send and receive

performance of embOS/IP on your hardware.

3.1.6.1 Running the embOS/IP speed client

To test the embOS/IP performance, you have to perform the following steps:

1. Start the Windows speed test server. The example application for the host-side is sup-

plied as executable and in source code in the Windows\SpeedTestServer\ directory.

To run the speed test server, simply start the executable, for example by double-click-

ing it or open the supplied Visual C project and compile and start the application.

2. Add OS_IP_SpeedClient.c to your project.

3. Customize the Local defines, configurable section of OS_IP_SpeedClient.c.

Change the macro SERVER_IP_ADDR accordant to your configuration. For exam-

ple, if the Windows host PC running the speed test server uses the IP address

192.168.5.15, change the SERVER_IP_ADDR macro to 0xC0A8050F. If you have

changed the port which the Windows host application uses to listen, change the

macro SERVER_PORT accordingly.

4. Build and download the speed client into your target. The target connects to the

server and starts the transmission.

3.1.7 embOS/IP start (OS_IP_Start.c)

Demonstrates use of the IP stack without any server or client program. To ping the

target, use the command line: ping <target-ip> where <target-ip> represents the

IP address of the target, which depends on the configuration and is usually

192.168.5.230 if the DHCP client is not enabled.

3.1.8 embOS/IP UDP discover (OS_IP_UDPDiscover.c /

OS_IP_UDPDiscoverZeroCopy.c)

To test the embOS/IP UDP discover example, you have to perform the following

steps:

1. Start the Windows UDP discover example application. The example application for the

host-side is supplied as executable and in source code in the Windows\UDPDiscover\

directory. To run the UDP discover example, simply start the executable, for example

by double-clicking it or open the supplied Visual C project and compile and start the

application.

2. Add OS_IP_UDPDiscover.c to your project.

3. Customize the Local defines, configurable section of OS_IP_UDPDiscover.c.

By default, the example uses port 50020. If you have changed the port that the

Windows host application uses, change the macro PORT accordingly.

4. Build and download the UDP discover example into your target. The target sends

an answer for every received discover packet. The related host application sends

discover packets as UDP broadcasts and waits for the feedback of the targets

which are available in the subnet.

40 CHAPTER 3 Example applications

Chapter 4

Core functions

In this chapter, you will find a description of each embOS/IP core function.

42 CHAPTER 4 Core functions
UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
4.1 API functions
The table below lists the available API functions within their respective categories.
Function Description
Configuration functions
IP_AddBuffers() Adds buffers to the TCP/IP stack.
IP_AddEtherInterface() Adds an Ethernet interface to the stack.
IP_AllowBackpressure() Activates back pressure.
IP_AssignMemory() Assigns memory.
IP_ARP_ConfigAgeout() Configures the ARP cache timeout.
IP_ARP_ConfigAgeoutNoReply() Configures the ARP cache timeout for 
request sent without a reply yet.
IP_ARP_ConfigAgeoutSniff() Configures the ARP cache timeout for 
entries sniffed from incoming packets.
IP_ARP_ConfigAllowGratuitousARP() Configures allow/disallow of using infor-
mation from gratuitous ARP packets.
IP_ARP_ConfigMaxRetries() Configures max. ARP request resends.
IP_ARP_ConfigNumEntries() Configures number of ARP cache entries.
IP_ConfTCPSpace() Configures the send and receive space.
IP_DNS_SetMaxTTL() Sets the maximum TTL of a DNS entry.
IP_DNS_SetServer() Sets the DNS server.
IP_ICMP_Add() Adds ICMP to the stack.
IP_IGMP_Add() Adds IGMP to the stack.
IP_IGMP_JoinGroup() Joins an IGMP group.
IP_IGMP_LeaveGroup() Leaves an IGMP group.
IP_NI_ConfigPoll() Select polled mode for the network inter-
face.
IP_NI_SetTxBufferSize() Configures the Tx buffer size used by the 
network interface driver.
IP_SetAddrMask() Sets the address mask of the first inter-
face interface.
IP_SetAddrMaskEx() Sets the address mask of the selected 
interface.
IP_SetGWAddr() Sets the gateway address of the selected 
interface.
IP_SetHWAddr() Sets the hardware address of the first 
interface.
IP_SetHWAddrEx() Sets the hardware address of the 
selected interface.
IP_SetMTU() Sets the maximum transmission unit of 
an interface.
IP_SetSupportedDuplexModes() Sets the supported duplex modes.
IP_SetTTL() Sets the TTL of an IP packet.
IP_SOCKET_SetDefaultOptions() Sets the socket options which should be 
enabled by default.
IP_SOCKET_SetLimit() Sets the maximum number of available 
sockets.
IP_TCP_Add() Adds TCP to the stack.
IP_TCP_Set2MSLDelay() Sets the maximum segment lifetime.
IP_TCP_SetConnKeepaliveOpt() Sets the keepalive options.
IP_TCP_SetRetransDelayRange() Sets retransmission delay range.
IP_UDP_Add() Adds UDP to the stack.
Table 4.1: embOS/IP API function overview

UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
43
Management functions
IP_DeInit() Deinitialization function of the stack.
IP_Init() Initialization function of the stack.
IP_Task() Main task for starting the stack. 
IP_RxTask() Reads all available packets and sleeps 
until a new packet is received.
IP_Exec() Checks if any packet has been received 
and handles timers.
Network interface configuration and handling functions
IP_NI_ConfigPHYAddr() Configures the PHY address.
IP_NI_ConfigPHYMode() Configures the PHY mode.
IP_NI_ConfigPoll() Select polled mode for the network inter-
face.
IP_NI_ForceCaps() Allows forcing of hardware capabilities.
IP_NI_SetTxBufferSize() Configures the Tx buffer size used by the 
network interface driver.
Other IP stack functions
IP_GetAddrMask() Returns the IP address and the subnet 
mask of the device.
IP_GetCurrentLinkSpeed() Returns the current link speed.
IP_GetCurrentLinkSpeedEx() Returns the current link speed of the 
selected interface.
IP_GetGWAddr() Returns the gateway address of the 
device.
IP_GetHWAddr() Returns the hardware address (MAC) of 
the device.
IP_GetIPAddr() Returns the IP address of the device.
IP_GetIPPacketInfo() Returns the start address of the data part 
of an IP packet.
IP_GetRawPacketInfo() Returns the start address of the raw data 
part of an IP packet.
IP_GetVersion() Returns the version number of embOS/IP. 
IP_ICMP_SetRxHook() Sets a hook function which will be called 
if target receives a ping packet.
IP_IFaceIsReady() Checks if the interface is ready.
IP_IFaceIsReadyEx() Checks if the specified interface is ready.
IP_PrintIPAddr() Convert an 4 byte IP address to a dots-
and-number string.
IP_SendPacket() Sends a user defined packet on the inter-
face.
IP_SendPing() Sends an ICMP Echo Request.
IP_SendPingEx() Sends an ICMP Echo Request.
IP_SetRxHook() Sets a hook function that handles all 
received packets.
Function Description
Table 4.1: embOS/IP API function overview (Continued)

44 CHAPTER 4 Core functions

4.2 Configuration functions

4.2.1 IP_AddBuffers()

Description

Adds buffers to the TCP/IP stack. This is a configuration function, typically called

from IP_X_Config(). It needs to be called 2 times, one per buffer size.

Prototype

void IP_AddBuffers ( int NumBuffers,

int BytesPerBuffer );

Parameter

Additional information

embOS/IP requires small and large buffers. We recommend to define the size of the

big buffers to 1536 to allow a full Ethernet packet to fit. The small buffers are used to

store packets which encapsulates no or few application data like protocol manage-

ment packets (TCP SYNs, TCP ACKs, etc.). We recommend to define the size of the

small buffers to 256 bytes.

Example

IP_AddBuffers(20, 256); // 20 small buffers, each 256 bytes.

IP_AddBuffers(12, 1536); // 12 big buffers, each 1536 bytes.

Parameter Description

NumBuffers [IN] The number of buffers.

BytesPerBuffer [IN] Size of buffers in bytes.

Table 4.2: IP_AddBuffers() parameter list

46 CHAPTER 4 Core functions

4.2.2 IP_AddEtherInterface()

Description

Adds an Ethernet interface.

Prototype

void IP_AddEtherInterface ( const IP_HW_DRIVER * pDriver );

Parameter

Additional information

Refer to Available network interface drivers on page 219 for a list of available net-

work interface drivers.

Example

IP_AddEtherInterface(&IP_Driver_SAM7X); // Add Ethernet driver for your hardware

Parameter Description

pDriver [IN] A pointer to a network interface driver structure.

Table 4.3: IP_AddEtherInterface() parameter list

4.2.3 IP_AllowBackpressure()

Description

Allows back pressure if the driver supports this feature.

Prototype

void IP_AllowBackpressure ( int v );

Parameter

Additional information

Back pressure is a window-based flow control mechanism for the half-duplex mode.

It is a sort of feedback-based congestion control mechanism. The intent of this mech-

anism is to prevent loss by providing back pressure to the sending NIC on ports that

are going too fast to avoid loss. Back pressure is enabled by default.

Parameter Description

v[IN] Zero to disable, 1 to enable back pressure.

Table 4.4: IP_AllowBackPressure() parameter list

48 CHAPTER 4 Core functions

4.2.4 IP_AssignMemory()

Description

Assigns memory to the TCP/IP stack.

Prototype

void IP_AssignMemory ( U32 * pMem,

U32 NumBytes );

Parameter

Additional information

IP_AssignMemory() should be the first function which is called in IP_X_Config().

The amount of RAM required depends on the configuration and the respective appli-

cation purpose. The assigned memory pool is required for the socket buffers, mem-

ory buffers, etc.

Example

#define ALLOC_SIZE 0x8000 // Size of memory dedicated to the stack in bytes

U32 _aPool[ALLOC_SIZE / 4]; // Memory area used by the stack.

IP_AssignMemory(_aPool, sizeof(_aPool));

Parameter Description

pMem [IN] A pointer to the start of the memory region which should be

assigned.

NumBytes [IN] Number of bytes which should be assigned.

Table 4.5: IP_AssignMemory() parameter list

4.2.5 IP_ARP_ConfigAgeout()

Description

Configures the timeout for cached ARP entries.

Prototype

void IP_ARP_ConfigAgeout ( U32 Ageout );

Parameter

Parameter Description

Ageout [IN] Timeout in ms after which an entry is deleted from the ARP

cache. Default: 120s.

Table 4.6: IP_ARP_ConfigAgeout() parameter list

50 CHAPTER 4 Core functions

4.2.6 IP_ARP_ConfigAgeoutNoReply()

Description

Configures the timeout for an ARP entry that has been added due to sending an ARP

request to the network that has not been answered yet.

Prototype

void IP_ARP_ConfigAgeoutNoReply ( U32 Ageout );

Parameter

Parameter Description

Ageout [IN] Timeout in ms after which an entry is deleted in case we are

still waiting for an ARP response. Default: 3s.

Table 4.7: IP_ARP_ConfigAgeoutNoReply() parameter list

4.2.7 IP_ARP_ConfigAgeoutSniff()

Description

Configures the timeout for cached ARP entries that have been cached from incoming

packets instead from sending an ARP request.

Prototype

void IP_ARP_ConfigAgeoutSniff ( U32 Ageout );

Parameter

Parameter Description

Ageout [IN] Timeout in ms after which an entry is deleted from the ARP

cache.

Table 4.8: IP_ARP_ConfigAgeoutSniff() parameter list

52 CHAPTER 4 Core functions

4.2.8 IP_ARP_ConfigAllowGratuitousARP()

Description

Configures if gratuitous ARP packets from other network members are allowed to

update the ARP cache.

Prototype

void IP_ARP_AllowGratuitousARP ( U8 OnOff );

Parameter

Additional information

Gratuitous ARP packets allow the network to update itself by sending out informa-

tions about changes regarding IP and hardware ID assignments. As this behaviour

helps the network to become more stable and helps to manage itself it is on by

default.

In case you consider gratuitous ARP packets as a security risk

IP_ARP_ConfigAllowGratuitousARP() can be used to disallow this behaviour.

Parameter Description

OnOff [IN] 0: Off; 1: On. Default: On.

Table 4.9: IP_ConfigAllowGratuitousARP() parameter list

4.2.9 IP_ARP_ConfigMaxRetries()

Description

Configures how often an ARP request is resent before considering the request failed.

Prototype

void IP_ARP_ConfigConfigMaxRetries ( unsigned Retries );

Parameter

Parameter Description

Retries [IN] Number of retries for sending an ARP request.

Table 4.10: IP_ARP_ConfigMaxRetries() parameter list

54 CHAPTER 4 Core functions

4.2.10 IP_ARP_ConfigNumEntries()

Description

Configures the maximum number of possible entries in the ARP cache.

Prototype

int IP_ARP_ConfigNumEntries ( unsigned NumEntries );

Parameter

Retrurn value

0: O.K., the stack will try to allocate the requested number of entries.

-1: Error, called after IP_Init().

Additional information

IP_ARP_ConfigNumEntries() has to be called before IP_Init().

Parameter Description

NumEntries [IN] Number of max. entries in ARP cache list.

Table 4.11: IP_ARP_ConfigNumEntries() parameter list

4.2.11 IP_ConfTCPSpace()

Description

Configures the size of the TCP send and receive window size.

Prototype

void IP_ConfTCPSpace ( unsigned SendSpace,

unsigned RecvSpace );

Parameter

Additional information

The receive window size is the amount of unacknowledged data a sender can send to

the receiver on a particular TCP connection before it gets an acknowledgment.

Parameter Description

SendSpace [IN] Size of the send window.

RecvSpace [IN] Size of the receive window.

Table 4.12: IP_ConfTCPSpace() parameter list

56 CHAPTER 4 Core functions

4.2.12 IP_DNS_SetMaxTTL()

Description

Sets the maximum Time To Live (TTL) of a DNS entry in seconds.

Prototype

void IP_DNS_SetMaxTTL( U32 TTL );

Parameter

Additional information

The real TTL is the minimum of TTL and the TTL specified by the DNS server for the

entry. The embOS/IP default for the maximum TTL of an DNS entry is 600 seconds.

Parameter Description

TTL [IN] Maximum TTL of a DNS entry in seconds.

Table 4.13: IP_DNS_SetMaxTTL() parameter list

4.2.13 IP_DNS_SetServer()

Description

Sets the DNS server that should be used.

Prototype

void IP_DNS_SetServer ( U32 DNSServerAddr );

Parameter

Additional information

If a DHCP server is used for configuring your target, IP_DNS_SetServer() should not

be called. The DNS server settings are normally part of the DHCP configuration

setup. The DNS server has to be defined before calling gethostbyname() to resolve

an internet address. Refer to gethostbyname() on page 116 for detailed information

about resolving an internet address.

Parameter Description

DNSServerAddr [IN] Address of DNS server.

Table 4.14: IP_DNS_SetServer() parameter list

58 CHAPTER 4 Core functions

4.2.14 IP_ICMP_Add()

Description

Adds ICMP to the stack.

Prototype

void IP_ICMP_Add ( void );

Additional information

IP_ICMP_Add() adds ICMP to the stack. The function should be called during the ini-

tialization of the stack. In the supplied sample configuration files IP_ICMP_Add() is

called from IP_X_Config(). If you remove the call of IP_ICMP_Add(), the ICMP code

will not be available in your application.

4.2.15 IP_IGMP_Add()

Description

Adds IGMP to the stack.

Prototype

void IP_IGMP_Add ( void );

Additional information

IP_IGMP_Add() adds IGMP (Internet Group Management Protocol) to the stack. The

function should be either called during the initialization of the stack by adding it to

your IP_X_Config() or should be called after IP_Init(). If you remove the call of

IP_IGMP_Add(), the ICMP code will not be available in your application.

60 CHAPTER 4 Core functions

4.2.16 IP_IGMP_JoinGroup()

Description

Joins an IGMP group.

Prototype

void IP_IGMP_JoinGroup ( unsigned IFace,

IP_ADDR GroupIP );

Parameter

Additional information

Calling this function should be only done after IP_init() as we relay on an already

configured HW addr.

Multicast is a technique to distribute a packet to multiple receivers in a network by

sending only one packet. Handling of who will receive the packet is not done by the

sender but instead is done by network hardware such as routers or switched hubs

that will dupplicate the packet and send it to everyone that participates the chosen

group.

The target does not actively participate by sending a join request. The network hard-

ware periodically broadcasts membership querys throughout the network that have

to be answered with a membership report in case we want to participate in the que-

ried group.

Example

/* Excerpt from IP.h */

#define IP_IGMP_MCAST_ALLHOSTS_GROUP 0xE0000001uL // 224.0.0.1

#define IP_IGMP_MCAST_ALLRPTS_GROUP 0xE0000016uL // 224.0.0.22, IGMPv3

/* Excerpt from the UPnP code */

#define SSDP_IP 0xEFFFFFFA // Simple service discovery protocol IP, 239.255.255.250

IP_IGMP_Add(); // IGMP is needed for UPnP

// Join IGMP ALLHOSTS group and IGMP group for SSDP

IP_IGMP_JoinGroup(0, IP_IGMP_MCAST_ALLHOSTS_GROUP);

IP_IGMP_JoinGroup(0, SSDP_IP);

Parameter Description

IFace [IN] Zero-based index of available interfaces.

GroupIP [IN] IGMP group IP addr.

Table 4.15: IP_IGMP_JoinGroup() parameter list

4.2.17 IP_IGMP_LeaveGroup()

Description

Leaves an IGMP group.

Prototype

void IP_IGMP_LeaveGroup ( unsigned IFace,

IP_ADDR GroupIP );

Parameter

Additional information

The target does not actively participate by sending a leave request. Instead the tar-

get will change its filters to no longer receiving IGMP membership querys and will

then be removed from the list of participants of the network hardware after a time-

out.

Example

/* Excerpt from IP.h */

#define IP_IGMP_MCAST_ALLHOSTS_GROUP 0xE0000001uL // 224.0.0.1

#define IP_IGMP_MCAST_ALLRPTS_GROUP 0xE0000016uL // 224.0.0.22, IGMPv3

/* Sample for leaving IGMP groups used for UPnP */

#define SSDP_IP 0xEFFFFFFA // Simple service discovery protocol IP, 239.255.255.250

// Leave IGMP ALLHOSTS group and IGMP group for SSDP

IP_IGMP_LeaveGroup(0, IP_IGMP_MCAST_ALLHOSTS_GROUP);

IP_IGMP_LeaveGroup(0, SSDP_IP);

Parameter Description

IFace [IN] Zero-based index of available interfaces.

GroupIP [IN] IGMP group IP addr.

Table 4.16: IP_IGMP_LeaveGroup() parameter list

62 CHAPTER 4 Core functions

4.2.18 IP_SetAddrMask()

Description

Sets the IP address and subnet mask of the first interface of the stack (interface 0).

Prototype

void IP_SetAddrMask ( U32 Addr,

U32 Mask );

Parameter

Additional information

The address mask should only be set if no DHCP server is used to obtain IP address,

subnet mask and default gateway. Refer to chapter DHCP client on page 169 for

detailed information about the usage of the embOS/IP DHCP client.

Example

IP_SetAddrMask(0xC0A80505, 0xFFFF0000); // IP: 192.168.5.5

// Subnet mask: 255.255.0.0

Parameter Description

Addr [IN] 4-byte IPv4 address.

Mask [IN] Subnet mask.

Table 4.17: IP_SetAddrMask() parameter list

4.2.19 IP_SetAddrMaskEx()

Description

Sets the IP address and subnet mask of an interface.

Prototype

void IP_SetAddrMaskEx ( U8 IFace,

U32 Addr,

U32 Mask );

Parameter

Additional information

The address mask should only be set if no DHCP server is used to obtain IP address,

subnet mask and default gateway. Refer to chapter DHCP client on page 169 for

detailed information about the usage of the embOS/IP DHCP client.

Example

IP_SetAddrMaskEx(0, 0xC0A80505, 0xFFFF0000); // Interface: 0

// IP: 192.168.5.5

// Subnet mask: 255.255.0.0

Parameter Description

IFace [IN] Interface Id.

Addr [IN] 4-byte IPv4 address.

Mask [IN] Subnet mask.

Table 4.18: IP_SetAddrMaskEx() parameter list

64 CHAPTER 4 Core functions

4.2.20 IP_SetGWAddr()

Description

Sets the default gateway address of the selected interface.

Prototype

void IP_SetGWAddr ( U8 IFace,

U32 Addr );

Parameter

Additional information

The address mask should only be set if no DHCP server is used to obtain IP address,

subnet mask and default gateway. Refer to chapter DHCP client on page 169 for

detailed information about the usage of the embOS/IP DHCP client.

Example

IP_SetGWAddr(0, 0xC0A80101); // Interface: 0

// IPv4 address of the GW: 192.168.1.1

Parameter Description

IFace [IN] Interface Id.

Addr [IN] 4-byte gateway address.

Table 4.19: IP_SetGWAddrEx() parameter list

4.2.21 IP_SetHWAddr()

Description

Sets the Media Access Control address (MAC) of the first interface (interface 0).

Prototype

void IP_SetHWAddr( const U8 * pHWAddr );

Parameter

Additional information

The MAC address needs to be unique for production units.

Example

IP_SetHWAddr("\x00\x22\x33\x44\x55\x66");

Parameter Description

pHWAddr [IN] 6-byte MAC address.

Table 4.20: IP_SetHWAddr() parameter list

66 CHAPTER 4 Core functions

4.2.22 IP_SetHWAddrEx()

Description

Sets the Media Access Control address (MAC) of the selected interface.

Prototype

void IP_SetHWAddr( const U8 * pHWAddr );

Parameter

Additional information

The MAC address needs to be unique for production units.

Example

IP_SetHWAddrEx(0, "\x00\x22\x33\x44\x55\x66");

Parameter Description

pHWAddr [IN] 6-byte MAC address.

Table 4.21: IP_SetHWAddrEx() parameter list

4.2.23 IP_SetMTU()

Description

Allows to set the Maximum Transmission Unit (MTU) of the selected interface.

Prototype

void IP_SetMTU( U8 IFace,

U32 Mtu );

Parameter

Additional information

The Maximum Transmission Unit is the MTU from an IP standpoint, so the size of the

IP-packet without local net header. A typical value for ethernet is 1500, since the

maximum size of an Ethernet packet is 1518 bytes. Since Ethernet uses 12 bytes for

MAC addresses, 2 bytes for type and 4 bytes for CRC, 1500 bytes "payload" remain.

The minimum size of the MTU is 576 according to RFC 879. Refer to [RFC 879] - TCP

- The TCP Maximum Segment Size and Related Topics for more information about the

MTU.

A smaller MTU size is effective for TCP connections only, it does not affect UDP con-

nections. All TCP connections are guaranteed to work with any MTU in the permitted

range of 576 - 1500 bytes. The advantage of a smaller MTU is that smaller packets

are sent in TCP communication, resulting in reduced RAM requirements, especially if

the window size is also reduced. The disadvantage is a loss of communication speed.

Note: In the supplied embOS/IP example configurations, the MTU is used to con-

figure the maximum packet size that the stack can handle. This means that if you

lower the MTU (for example, set it to 576 bytes), the stack can only handle packets

up to that size. If you plan to use larger UDP packets, change the configuration

according to your requirements. For further information about the configuration of

the stack, refer to Configuring embOS/IP on page 255.

Parameter Description

IFace [IN] Zero-based index of available network interfaces.

Mtu [IN] Size of maximum transmission unit in bytes.

Table 4.22: IP_SetMTU() parameter list

68 CHAPTER 4 Core functions

4.2.24 IP_SetSupportedDuplexModes()

Description

Allows to set the allowed Duplex modes.

Prototype

int IP_SetSupportedDuplexModes( unsigned Unit,

unsigned DuplexMode);

Parameter

Valid values for parameter DuplexMode

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

DuplexMode [IN] OR-combination of one or more of the following valid values.

Table 4.23: IP_SetSupportedDuplexModes() parameter list

Value Description

IP_PHY_MODE_10_HALF Support 10 Mbit half-duplex

IP_PHY_MODE_10_FULL Support 10 Mbit full-duplex

IP_PHY_MODE_100_HALF Support 100 Mbit half-duplex

IP_PHY_MODE_100_FULL Support 100 Mbit full-duplex

4.2.25 IP_SetTTL()

Description

Sets the default value for the Time-To-Live IP header field.

Prototype

void IP_SetTTL ( int v );

Parameter

Additional information

By default, the TTL (Time-To-Live) is 64. The TTL field length of the IP is 8 bits. The

maximum value of the TTL field is therefore 255.

Parameter Description

v[IN] Time-To-Live value.

Table 4.24: IP_SetTTL() parameter list

70 CHAPTER 4 Core functions

4.2.26 IP_SOCKET_SetDefaultOptions()

Description

Allows to set the maximum transmission unit (MTU) of an interface.

Prototype

void IP_SOCKET_SetDefaultOptions ( U16 v );

Parameter

Parameter Description

[IN] Socket options which should be enabled. By default, keepalive

(SO_KEEPALIVE) socket option is enabled. Refer to setsockopt() on

page 132 for a list of supported socket options.

Table 4.25: IP_SOCKET_SetDefaultOptions() parameter list

4.2.27 IP_SOCKET_SetLimit()

Description

Sets the maximum number of available sockets.

Prototype

void IP_SOCKET_SetLimit ( unsigned Limit );

Parameter

Parameter Description

Limit [IN] Sets a limit on number of sockets which can be created. The

embOS/IP default is 0 which means that no limit is set.

Table 4.26: IP_SOCKET_SetLimit() parameter list

72 CHAPTER 4 Core functions

4.2.28 IP_TCP_Add()

Description

Adds TCP to the stack.

Prototype

void IP_TCP_Add ( void );

Additional information

IP_TCP_Add() adds TCP to the stack. The function should be called during the initial-

ization of the stack. In the supplied sample configuration files IP_TCP_Add() is called

from IP_X_Config(). If you remove the call of IP_TCP_Add(), the TCP code will not

be available in your application.

4.2.29 IP_TCP_Set2MSLDelay()

Description

Sets the maximum segment lifetime (MSL).

Prototype

void IP_TCP_Set2MSLDelay( unsigned v );

Parameter

Additional information

The maximum segment lifetime is the amount of time any segment can exist in the

network before being discarded. This time limit is constricted. When TCP performs an

active close the connection must stay in TIME_WAIT (2MSL) state for twice the MSL

after sending the final ACK.

Refer to [RFC 793] - TCP - Transmission Control Protocol for more information about

TCP states.

Parameter Description

v[IN] Maximum segment lifetime. The embOS/IP default is 2 sec-

onds.

Table 4.27: IP_TCP_Set2MSLDelay() parameter list

74 CHAPTER 4 Core functions

4.2.30 IP_TCP_SetConnKeepaliveOpt()

Description

Sets the keepalive options.

Prototype

void IP_TCP_SetConnKeepaliveOpt( U32 Init,

U32 Idle,

U32 Period,

U32 MaxRep );

Parameter

Additional information

Keepalives are not part of the TCP specification, since they can cause good connec-

tions to be dropped during transient failures. For example, if the keepalive probes are

sent during the time that an intermediate router has crashed and is rebooting, TCP

will think that the client's host has crashed, which is not what has happened. Never-

theless, the keepalive feature is very useful for embedded server applications that

might tie up resources on behalf of a client, and want to know if the client host

crashes.

Parameter Description

Init [IN] Maximum time for TCP-connection open (response to SYN) in

ms. The embOS/IP default is 20 seconds.

Idle [IN] Time of TCP-inactivity before first keepalive probe is sent in

ms. The embOS/IP default is 60 seconds.

Period [IN] Time of TCP-inactivity between keepalive probes in ms. The

embOS/IP default is 10 seconds.

MaxRep [IN] Number of keepalive probes before we give up and close the

connection. The embOS/IP default is 8 repetitions.

Table 4.28: IP_TCP_SetConnKeepaliveOpt() parameter list

4.2.31 IP_TCP_SetRetransDelayRange()

Description

Sets the retransmission delay range.

Prototype

void IP_TCP_SetRetransDelayRange( unsigned RetransDelayMin,

unsigned RetransDelayMax );

Parameter

Additional information

TCP is a reliable transport layer. One of the ways it provides reliability is for each end

to acknowledge the data it receives from the communication partner. But data seg-

ments and acknowledgments can get lost. TCP handles this by setting a timeout

when it sends data, and if the data is not acknowledged when the timeout expires, it

retransmits the data. The timeout and retransmission is the measurement of the

round-trip time (RTT) experienced on a given connection. The RTT can change over

time, as routes might change and as network traffic changes, and TCP should track

these changes and modify its timeout accordingly. IP_TCP_SetRetransDelayRange()

should be called if the default limits are not sufficient for your application.

Parameter Description

RetransDelayMin [IN] Minimum time before first retransmission. The embOS/IP

default is 200 ms.

RetransDelayMax [IN] Maximum time to wait before a retransmission. The

embOS/IP default is 5 seconds.

Table 4.29: IP_TCP_SetRetransDelayRange() parameter list

76 CHAPTER 4 Core functions

4.2.32 IP_UDP_Add()

Description

Adds UDP to the stack.

Prototype

void IP_UDP_Add ( void );

Additional information

IP_UDP_Add() adds UDP to the stack. The function should be called during the initial-

ization of the stack. In the supplied sample configuration files IP_UDP_Add() is called

from IP_X_Config(). If you remove the call of IP_UDP_Add(), the UDP code will not

be available in your application.

4.3 Management functions

78 CHAPTER 4 Core functions

4.3.1 IP_DeInit()

Description

De-initializes the TCP/IP stack.

Prototype

void IP_DeInit ( void );

Additional information

IP_DeInit() de-initializes the IP stack. This function should be the very last embOS/

IP function called and is typically not needed if you do not need to shutdown your

whole application for a special reason.

Example

#include "IP.h"

void main(void) {

IP_Init();

* Use the stack

IP_DeInit();

}

4.3.2 IP_Init()

Description

Initializes the TCP/IP stack.

Prototype

void IP_Init ( void );

Additional information

IP_Init() initializes the IP stack and creates resources required for an OS integra-

tion. This function must be called before any other embOS/IP function is called.

Example

#include "IP.h"

void main(void) {

IP_Init();

* Use the stack

}

80 CHAPTER 4 Core functions

4.3.3 IP_Task()

Description

Main task for starting the stack. After startup, it settles into a loop handling received

packets. This loop sleeps until a packet has been queued in the receive queue; then

it should be awakened by the driver which queued the packet.

Prototype

void IP_Task ( void );

Additional information

Implementing this task is the simplest way to include embOS/IP into your project.

Typical stack usage is approximately 440 bytes. To be on the safe side set the size of

the task stack to 1024 bytes.

Note: The priority of task IP_Task should be higher then the priority of an appli-

cation task which uses the stack.

Example

#include <stdio.h>

#include "RTOS.h"

#include "BSP.h"

#include "IP.h"

#include "IP_Int.h"

static OS_STACKPTR int _Stack0[512]; // Task stacks

static OS_TASK _TCB0; // Task-control-blocks

static OS_STACKPTR int _IPStack[1024]; // Task stacks

static OS_TASK _IPTCB; // Task-control-blocks

/*********************************************************************

* MainTask

void MainTask(void);

void MainTask(void) {

printf("****************************************\nProgram start\n");

IP_Init();

OS_SetPriority(OS_GetTaskID(), 255); // This task has highest prio!

OS_CREATETASK(&_IPTCB, "IP_Task", IP_Task, 150, _IPStack);

while (1) {

BSP_ToggleLED(1);

OS_Delay (200);

}

/**********************************************************

* main

void main(void) {

BSP_Init();

BSP_SetLED(0);

OS_IncDI(); /* Initially disable interrupts */

OS_InitKern(); /* initialize OS */

OS_InitHW(); /* initialize Hardware for OS */

OS_CREATETASK(&_TCB0, "MainTask", MainTask, 100, _Stack0);

OS_Start();

}

4.3.4 IP_RxTask()

Description

The task reads all available packets from the network interface and sleeps until a new

packet is received.

Prototype

void IP_RxTask ( void );

Additional information

This task is optional. Refer to Tasks and interrupt usage on page 19 for detailed

information about the task and interrupt handling of embOS/IP. Typical stack usage is

approximately 150 bytes. To be on the safe side set the size of the task stack to 1024

bytes.

Note: The priority of task IP_RxTask() should be higher then the priority of an

application task which uses the stack.

82 CHAPTER 4 Core functions

4.3.5 IP_Exec()

Description

Checks if the driver has received a packet and handles timers.

Prototype

void IP_Exec ( void );

Additional information

This function is normally called from an endless loop in IP_Task(). If no particular IP

task is implemented in your project, IP_Exec() should be called regularly.

4.4 Network interface configuration and handling

functions

84 CHAPTER 4 Core functions

4.4.1 IP_NI_ConfigPHYAddr()

Description

Configures the PHY address.

Prototype

void IP_NI_ConfigPHYAddr ( unsigned Unit,

U8 Addr );

Additional information

The PHY address is a 5-bit value. The available embOS/IP drivers try to detect the

PHY address automatically, therefore this should not be called. If you use this func-

tion to set the address explicitly, the function must be called from within

IP_X_Config(). Refer to IP_X_Configure() on page 256.

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Addr [IN] 5-bit address.

Table 4.30: IP_NI_ConfigPHYAddr() parameter list

4.4.2 IP_NI_ConfigPHYMode()

Description

Configures the PHY mode.

Prototype

void IP_NI_ConfigPHYMode ( unsigned Unit,

U8 Mode );

Valid values for parameter Mode

Additional information

The PHY can be connected to the MAC via two different modes, MII or RMII. Refer to

section MII / RMII: Interface between MAC and PHY on page 23 for detailed informa-

tion about the differences of the MII and RMII modes.

The selection which mode is used is normally done correctly by the hardware. The

mode is typically sampled during power-on RESET. If you use this function to set the

mode explicitly, the function must be called from within IP_X_Config(). Refer to

IP_X_Configure() on page 256.

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Mode [IN] The operating mode of the PHY.

Table 4.31: IP_NI_ConfigPHYMode() parameter list

Value Description

IP_PHY_MODE_MII Phy uses the Media Independent Interface

(MII).

IP_PHY_MODE_RMII Phy uses the Reduced Media Independent

Interface (RMII).

86 CHAPTER 4 Core functions

4.4.3 IP_NI_ConfigPoll()

Description

Select polled mode for the network interface. This should be used only if the network

interface can not activate an ISR itself.

Prototype

void IP_NI_ConfigPoll( unsigned Unit );

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 4.32: IP_NI_ConfigPoll() parameter list

4.4.4 IP_NI_ForceCaps()

Description

Allows to force capabilities to be set for an interface. Typically this is used to allow

the checksum calculation capabilities to be set manually. Typically this is used to give

the target a performance boost in high traffic applications on stable networks, where

the occurence of wrong checksums is unlikely.

Prototype

void IP_NI_ForceCaps( U8 IFace,

U8 CapsForcedMask,

U8 CapsForcedValue );

Example

Forcing the capability bits 0 to value ’0’ and bit 2 to value ’1’ for the first interface

can be done as shown in the code example below:

IP_NI_ForceCaps(0, 5, 4);

Parameter Description

IFace [IN] Zero-based index of available network interfaces.

CapsForcedMask [IN] Capabilities mask. For a list of driver capabilities please

refer to IP.h and look for the “Driver capabilities“ section.

CapsForcedValue [IN] Value mask for the capabilities to force.

Table 4.33: IP_NI_ConfigPoll() parameter list

88 CHAPTER 4 Core functions

4.4.5 IP_NI_SetTxBufferSize()

Description

Sets the size of the Tx buffer of the network interface.

Prototype

int IP_NI_SetTxBufferSize ( unsigned Unit,

U8 NumBytes );

Return value

-1: Not supported by the network interface driver.

0: OK

1: Error, called after driver initialization has been completed.

Additional information

The default Tx buffer size is 1536 bytes. It can be useful to reduce the buffer size on

systems with less RAM and an application that uses a small MTU. According to RFC

576 bytes is the smallest possible MTU. The size of the Tx buffer should be at least

MTU + 16 bytes for Ethernet header and footer. The function should be called in

IP_X_Config().

Note: This function is not implemented in all network interface drivers, since not

all Media Access Controllers (MAC) support variable buffer sizes.

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

NumBytes [IN] Size of the Tx buffer (at least size of the MTU + 16 bytes for

Ethernet.)

Table 4.34: IP_NI_SetTxBufferSize() parameter list

4.5 Other IP stack functions

90 CHAPTER 4 Core functions

4.5.1 IP_GetAddrMask()

Description

Returns the IP address and the subnet mask of the device in network byte order (for

example, 192.168.1.1 is returned as 0xc0a80101).

Prototype

void IP_GetAddrMask ( U8 IFace, U32 * pAddr, U32 * pMask );

Parameter

Parameter Description

IFace [IN] Interface.

pAddr [OUT] Address to store the IP address.

pMask [OUT] Address to store the subnet mask.

Table 4.35: IP_GetAddrMask() parameter list

4.5.2 IP_GetCurrentLinkSpeed()

Description

Returns the current link speed of the first interface (interface ID ’0’).

Prototype

int IP_GetCurrentLinkSpeed( void );

Return value

0: link speed unknown

1: link speed is 10 Mbit/s

2: link speed is 100 Mbit/s

3: link speed is 1000 Mbit/s

Additional information

The application should check if the link is up before a packet will be sent. It can take

2-3 seconds till the link is up if the PHY has been reset.

Example

// Wait until link is up.

while (IP_GetCurrentLinkSpeed() == 0) {

OS_IP_Delay(100);

}

92 CHAPTER 4 Core functions

4.5.3 IP_GetCurrentLinkSpeedEx()

Description

Returns the current link speed of the selected interface.

Prototype

int IP_GetCurrentLinkSpeedEx( unsigned IFaceId );

Parameter

Return value

0: link speed unknown

1: link speed is 10 Mbit/s

2: link speed is 100 Mbit/s

3: link speed is 1000 Mbit/s

Additional information

The application should check if the link is up before a packet will be sent. It can take

2-3 seconds till the link is up if the PHY has been reset.

Example

// Wait until link is up.

while (IP_GetCurrentLinkSpeedEx(0) == 0) {

OS_IP_Delay(100);

}

Parameter Description

IFaceId [IN] Interface Id (zero-based).

Table 4.36: IP_GetCurrentLinkSpeedEx() parameter list

4.5.4 IP_GetGWAddr()

Description

Returns the gateway address of the interface in network byte order (for example,

192.168.1.1 is returned as 0xc0a80101).

Prototype

U32 IP_GetGWAddr ( U8 IFace );

Parameter

Return value

The gateway address of the interface.

Parameter Description

IFace [IN] Number of interface.

Table 4.37: IP_GetGWAddr() parameter list

94 CHAPTER 4 Core functions

4.5.5 IP_GetHWAddr()

Description

Returns the hardware address (Media Access Control address) of the interface.

Prototype

void IP_GetHWAddr ( U8 IFace, U8 * pDest, unsigned Len );

Parameter

Parameter Description

IFace [IN] Number of interface.

pDest [OUT] Address of the buffer to store the 48-bit MAC address.

Len [IN] Size of the buffer. Should be at least 6-bytes.

Table 4.38: IP_GetHWAddr() parameter list

4.5.6 IP_GetIPAddr()

Description

Returns the IP address of the interface.

Prototype

U32 IP_GetIPAddr( U8 IFace );

Parameter

Return value

The IP address of the interface in network byte order (for example, 192.168.1.1 is

returned as 0xc0a80101).

Example

void PrintIFaceIPAddr(void) {

char ac[16];

U32 IPAddr;

IPAddr = IP_GetIPAddr(0);

IP_PrintIPAddr(ac, IPAddr, sizeof(ac));

printf("IP Addr: %s\n", ac);

}

Parameter Description

IFace [IN] Number of interface.

Table 4.39: IP_GetIPAddr() parameter list

96 CHAPTER 4 Core functions

4.5.7 IP_GetIPPacketInfo()

Description

Returns the start address of the data part of an IP packet.

Prototype

const char * IP_GetIPPacketInfo( IP_PACKET * pPacket );

Parameter

Return value

0 > Start address of the data part of the IP packet.

0 On failure.

Example

/*********************************************************************

* _pfOnRxICMP

static int _pfOnRxICMP(IP_PACKET * pPacket) {

const char * pData;

pData = IP_GetIPPacketInfo(pPacket);

if(*pData == 0x08) {

printf("ICMP echo request received!\n");

}

if(*pData == 0x00) {

printf("ICMP echo reply received!\n");

}

return 0;

}

Parameter Description

pPacket [IN] Pointer to an IP_PACKET structure.

Table 4.40: IP_GetIPPacketInfo() parameter list

4.5.8 IP_GetRawPacketInfo()

Description

Returns the start address of the raw data part of an IP packet.

Prototype

const char * IP_GetRawPacketInfo( IP_PACKET * pPacket,

U16 * pNumBytes );

Parameter

Return value

0 > Start address of the raw data part of the IP packet.

0 On failure.

Parameter Description

pPacket [IN] Pointer to an IP_PACKET structure.

pNumBytes [OUT] Length of the packet.

Table 4.41: IP_GetRawPacketInfo() parameter list

98 CHAPTER 4 Core functions

4.5.9 IP_GetVersion()

Description

Returns the version number of the stack.

Prototype

int IP_GetVersion ( void );

Additional information

The format of the version number: <Major><Minor><Minor><Revision><Revision>.

For example, the return value 10201 means version 1.02a.

4.5.10 IP_ICMP_SetRxHook()

Description

Sets a hook function which will be called if target receives a ping packet.

Prototype

void IP_ICMP_SetRxHook(IP_RX_HOOK * pf);

Parameter

Additional information

The return value of the callback function is relevant for the further processing of the

ICMP packet. A return value of 0 indicates that the stack has to process the packet

after the callback has returned. A return value of 1 indicates that the packet will be

freed directly after the callback has returned.

The prototype for the callback function is defined as follows:

typedef int (IP_RX_HOOK)(IP_PACKET * pPacket);

Example

/*********************************************************************

* Local defines, configurable

**********************************************************************

#define HOST_TO_PING 0xC0A80101

/*********************************************************************

* _pfOnRxICMP

static int _pfOnRxICMP(IP_PACKET * pPacket) {

const char * pData;

pData = IP_GetIPPacketInfo(pPacket);

if(*pData == 0x08) {

printf("ICMP echo request received!\n");

}

if(*pData == 0x00) {

printf("ICMP echo reply received!\n");

}

return 0; // Give packet back to the stack for further processing.

}

/*********************************************************************

* PingTask

void PingTask(void) {

int Seq;

char * s = "This is a ICMP echo request!";

while (IP_IFaceIsReady() == 0) {

OS_Delay(50);

}

IP_ICMP_SetRxHook(_pfOnRxICMP);

Seq = 1111;

while (1) {

BSP_ToggleLED(1);

OS_Delay (200);

IP_SendPing(htonl(HOST_TO_PING), s, strlen(s), Seq++);

}

Parameter Description

pf Pointer to the callback function of type IP_RX_HOOK.

Table 4.42: IP_ICMP_SetRxHook() parameter list

100 CHAPTER 4 Core functions

4.5.11 IP_IFaceIsReady()

Description

Checks if the interface is ready for usage. Ready for usage means that the target has

a physical link detected and a valid IP address.

Prototype

int IP_IFaceIsReady ( void );

Return value

1 network interface is ready.

0 network interface is not ready.

Additional information

The application has to check if the link is up before a packet will be sent and if the

interface is configured. If a DHCP server is used for configuring your target, this

function has to be called to assure that no application data will be sent before the

target is ready.

Example

// Wait until interface is ready.

while (IP_IFaceIsReady() == 0) {

OS_Delay(100);

}

101

4.5.12 IP_IFaceIsReadyEx()

Description

Checks if the specified interface is ready for usage. Ready for usage means that the

target has a physical link detected and a valid IP address.

Prototype

int IP_IFaceIsReadyEx ( unsigned IFaceId );

Return value

1 network interface is ready.

0 network interface is not ready.

Additional information

The application has to check if the link is up before a packet will be sent and if the

interface is configured. If a DHCP server is used for configuring your target, this

function has to be called to assure that no application data will be sent before the

target is ready.

Example

// Wait until second interface is ready.

while (IP_IFaceIsReadyEx(1) == 0) {

OS_Delay(100);

}

102 CHAPTER 4 Core functions

4.5.13 IP_PrintIPAddr()

Description

Convert an 4-byte IP address to a dots-and-number string.

Prototype

int IP_PrintIPAddr( char * pDest,

U32 IPAddr,

int BufferSize );

Parameter

Return value

0 on error. Size of the buffer is too small.

>0 on success. Length of the IP address string.

Example

void PrintIPAddr(void) {

U32 IPAddr;

char ac[16];

IPAddr = 0xC0A80801; // IP address: 192.168.8.1

IP_PrintIPAddr(ac, IPAddr, sizeof(ac));

printf("IP address: %s\n", ac); // Output: IP address: 192.168.8.1

}

Parameter Description

pDest [OUT] Buffer to store the IP address string.

IPAddr [IN] IP address in network byte order.

Buffersize [IN] Size of buffer pDest. Should be 16 byte to store an IPv4

address.

Table 4.43: IP_PrintIPAddr() parameter list

103

4.5.14 IP_SendPacket()

Description

Sends a user defined packet on the interface. The packet will not be modified by the

stack. IP_SendPacket() allocates a packet control block (IP_PACKET) and adds it to

the Out queue of the interface.

Prototype

int IP_SendPacket( unsigned IFace,

void * pData,

int NumBytes );

Parameter

Return value

0 O.K., packet in out queue

-1 Error: Could not allocate a packet control block

1 Error: Interface can not send

Parameter Description

IFace [IN] Zero-based interface index.

pData [IN] Data packet that should be sent.

Numbytes [IN] Length of data which should be sent.

Table 4.44: IP_SendPacket() parameter list

104 CHAPTER 4 Core functions

4.5.15 IP_SendPing()

Description

Sends a single “ping” (ICMP echo request) to the specified host.

Prototype

int IP_SendPing ( ip_addr host,

char * data,

unsigned datalen,

U16 pingseq );

Parameter

Return value

Returns 0 if ICMP echo request was successfully sent, else negative error message.

Additional information

If you call this function with activated logging, the ICMP reply or (in case of an error)

the error message will be sent to stdout. To enable the output of ICMP status mes-

sages, add the message type IP_MTYPE_ICMP to the log filter and the warn filter.

Refer to Debugging on page 433 for detailed information about logging.

Parameter Description

host [IN] 4-byte IPv4 address in network endian byte order.

data [IN] Ping data, NULL if do not care.

datalen [IN] Length of data to attach to ping request.

pingseq [IN] Ping sequence number.

Table 4.45: IP_SendPing() parameter list

105

4.5.16 IP_SendPingEx()

Description

Sends a single “ping” (ICMP echo request) to the specified host using the selected

interface.

Prototype

int IP_SendPingEx ( U32 IFaceId,

ip_addr host,

char * data,

unsigned datalen,

U16 pingseq );

Parameter

Return value

Returns 0 if ICMP echo request was successfully sent, else negative error message.

Additional information

If you call this function with activated logging, the ICMP reply or (in case of an error)

the error message will be sent to stdout. To enable the output of ICMP status mes-

sages, add the message type IP_MTYPE_ICMP to the log filter and the warn filter.

Refer to Debugging on page 433 for detailed information about logging.

Parameter Description

IFaceId [IN] Interface index (zero-based).

host [IN] 4-byte IPv4 address in network endian byte order.

data [IN] Ping data, NULL if do not care.

datalen [IN] Length of data to attach to ping request.

pingseq [IN] Ping sequence number.

Table 4.46: IP_SendPingEx() parameter list

106 CHAPTER 4 Core functions

4.5.17 IP_SetRxHook()

Description

Sets a hook function which will be called if target receives a packet.

Prototype

void IP_SetRxHook(IP_RX_HOOK * pf);

Parameter

Additional information

The return value of the callback function is relevant for the further processing of the

packet. A return value of 0 indicates that the stack has to process the packet after

the callback has returned. A return value of >0 indicates that the packet will be freed

directly after the callback has returned.

The prototype for the callback function is defined as follows:

typedef int (IP_RX_HOOK)(IP_PACKET * pPacket);

Example

Refer to IP_ICMP_SetRxHook() on page 99 for an example.

Parameter Description

pf Pointer to the callback function of type IP_RX_HOOK.

Table 4.47: IP_SetRxHook() parameter list

107

4.6 Stack internal functions, variables and data-struc-

tures

embOS/IP internal functions, variables and data-structures are not explained here as

they are in no way required to use embOS/IP. Your application should not rely on any

of the internal elements, as only the documented API functions are guaranteed to

remain unchanged in future versions of embOS/IP.

108 CHAPTER 4 Core functions

109

Chapter 5

Socket interface

The embOS/IP socket API is almost compatible to the Berkeley socket interface. The

Berkeley socket interface is the de facto standard for socket communication. All API

functions are described in this chapter.

110 CHAPTER 5 Socket interface
UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
5.1 API functions
The table below lists the available socket API functions.
Function Description
Socket inte r face
accept() Accepts an incoming attempt on a socket.
bind() Assigns a name to an unnamed socket.
closesocket() Closes an existing socket.
connect() Establishes a connection to a socket.
gethostbyname() Resolves a host name into an IP address.
getpeername() Returns the IP addressing information of 
the connected host.
getsockname() Returns the current name for the specified 
socket.
getsockopt() Returns the socket options.
listen() Marks a socket as accepting connections.
recv() Receives data from a connected socket.
recvfrom() Receives a datagram and stores the source 
address.
select() Checks if socket is ready.
send() Sends data on a connected socket.
sendto() Sends data to a specified address.
setsockopt() Sets a socket option.
shutdown() Disables sends or receives on a socket.
socket() Creates an unbound socket.
Helper macros
ntohl Converts a unsigned long value from net-
work to host byte order.
htonl Converts a unsigned long value from host 
byte order to network byte order.
htons Converts a unsigned short value from host 
byte order to network byte order.
ntohs Converts a unsigned short value from net-
work to host byte order.
Table 5.1: embOS/IP socket API function overview

111

5.1.1 accept()

Description

Accepts an incoming attempt on a socket.

Prototype

long accept ( long Socket,

struct sockaddr * pAddr,

int * pAddrLen );

Parameter

Return value

The returned value is a handle for the socket on which the actual connection will be

made.

-1 in case of an error.

Additional information

This call is used with connection-based socket types, currently with SOCK_STREAM.

Refer to socket() on page 135 for more information about the different socket types.

Before calling accept(), the used socket Socket has to be bound to an address with

bind() and should be listening for connections after calling listen(). accept()

extracts the first connection on the queue of pending connections, creates a new

socket with the same properties of Socket and allocates a new file descriptor for the

socket. If no pending connections are present on the queue, and the socket is not

marked as non-blocking, accept() blocks the caller until a connection is present. If

the socket is marked non-blocking and no pending connections are present on the

queue, accept() returns and reports an error. The accepted socket is used to read

and write data to and from the socket which is connected to this one; it is not used to

accept more connections. The original socket Socket remains open for accepting fur-

ther connections.

The argument pAddr is a result parameter that is filled in with the address of the

connecting entity as known to the communications layer. The exact format of the

pAddr parameter is determined by the domain in which the communication is occur-

ring. The pAddrLen is a value-result parameter. It should initially contain the amount

of space pointed to by pAddr.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pAddr

[OUT] An optional pointer to a buffer where the address of the con-

necting entity should be stored. The format of the address depends

on the defined address family which was defined when the socket

was created.

pAddrLen

[OUT] An optional pointer to an integer where the length of the

received address should be stored. Just like the format of the

address, the length of the address depends on the defined address

family.

Table 5.2: accept() parameter list

112 CHAPTER 5 Socket interface

5.1.2 bind()

Description

Assigns a name (port) to an unnamed socket.

Prototype

int bind ( long Socket,

struct sockaddr * pAddr,

int AddrLen );

Parameter

Return value

0 on success.

-1 on failure.

Additional information

When a socket is created with socket() it exists in a name space (address family)

but has no name assigned. bind() is used on an unconnected socket before subse-

quent calls to the connect() or listen() functions. bind() assigns the name

pointed to by pAddr to the socket.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pAddr

[IN] A pointer to a buffer where the address of the connecting entity

is stored. The format of the address depends on the defined address

family which was defined when the socket was created.

AddrLen [IN] The length of the address.

Table 5.3: bind() parameter list

113

5.1.3 closesocket()

Description

Closes an existing socket.

Prototype

int closesocket ( long Socket );

Parameter

Return value

0 on success.

-1 on failure.

Additional information

closesocket() closes a connection on the socket associated with Socket and the

socket descriptor associated with Socket will be returned to the free socket descrip-

tor pool. Once a socket is closed, no further socket calls should be made with it.

If the socket promises reliable delivery of data and SO_LINGER is set, the system will

block the caller on the closesocket() attempt until it is able to transmit the data or

until it decides it is unable to deliver the information (a timeout period, termed the

linger interval, is specified in the setsockopt() call when SO_LINGER is requested).

If SO_LINGER is disabled and a closesocket() is issued, the system will process the

close in a manner that allows the caller to continue as quickly as possible. If

SO_LINGER is enabled with a timeout period of ’0’ and a closesocket() is issued, the

system will perform a hard close.

Example

/*********************************************************************

* _CloseSocketGracefully()

* Function description

* Wrapper for closesocket() with linger enabled to verify a gracefully

* disconnect.

static int _CloseSocketGracefully(long pConnectionInfo) {

struct linger Linger;

Linger.l_onoff = 1; // Enable linger for this socket.

Linger.l_linger = 1; // Linger timeout in seconds

setsockopt(hSocket, SOL_SOCKET, SO_LINGER, &Linger, sizeof(Linger));

return closesocket(hSocket);

}

/*********************************************************************

* _CloseSocketHard()

* Function description

* Wrapper for closesocket() with linger option enabled to perform a hard close.

static int _CloseSocketHard(long hSocket) {

struct linger Linger;

Linger.l_onoff = 1; // Enable linger for this socket.

Linger.l_linger = 0; // Linger timeout in seconds

setsockopt(hSocket, SOL_SOCKET, SO_LINGER, &Linger, sizeof(Linger));

return closesocket(hSocket);

}

Parameter Description

Socket [IN] Socket descriptor of the socket that should be closed.

Table 5.4: closesocket() parameter list

114 CHAPTER 5 Socket interface

5.1.4 connect()

Description

Establishes a connection to a socket.

Prototype

int connect ( long Socket,

struct sockaddr * pAddr,

int AddrLen );

Parameter

Return value

0 on success.

-1 on failure.

Additional information

If Socket is of type SOCK_DGRAM, then this call specifies the peer with which the

socket is to be associated. pAddr defines the address to which datagrams are sent

and the only address from which datagrams are received.

If Socket is of type SOCK_STREAM, then this call attempts to make a connection to

another socket. The other socket is specified by pAddr which is an address in the

communications space of the socket. Each communications space interprets the

pAddr parameter in its own way.

Generally, stream sockets may successfully connect() only once; datagram sockets

may use connect() multiple times to change their association. Datagram sockets

may dissolve the association by connecting to an invalid address, such as a NULL

address.

If a connect is in progress and the socket is blocking, the connect call waits until con-

nected or an error to happen. If the socket is non-blocking (refer to setsockopt() on

page 132 for more information), 0 is returned.

You can use the getsockopt() function (refer to getsockopt() on page 120) to deter-

mine the status of the connect attempt.

Example

#define SERVER_PORT 1234

#define SERVER_IP_ADDR 0xC0A80101 // 192.168.1.1

/*********************************************************************

* _TCPClientTask

* Function description

* Creates a connection to a given IP address, TCP port.

static void _TCPClientTask(void) {

int TCPSockID;

struct sockaddr_in ServerAddr;

Parameter Description

Socket [IN] A descriptor identifying an unconnected socket.

pAddr

[IN] A pointer to a buffer where the address of the connecting entity

is stored. The format of the address depends on the defined address

family which was defined when the socket was created.

AddrLen

[IN] A pointer to an integer where the length of the received

address is stored. Just like the format of the address, the length of

the address depends on the defined address family.

Table 5.5: connect() parameter list

115

int ConnectStatus;

// Wait until link is up. This can take 2-3 seconds if PHY has been reset.

while (IP_GetCurrentLinkSpeed() == 0) {

OS_Delay(100);

}

while(1) {

TCPSockID = socket(AF_INET, SOCK_STREAM, 0); // Open socket

if (TCPSockID < 0) { // Error, Could not get socket

while (1) {

OS_Delay(20);

}

} else {

// Connect to server

ServerAddr.sin_family = AF_INET;

ServerAddr.sin_port = htons(SERVER_PORT);

ServerAddr.sin_addr.s_addr = htonl(SERVER_IP_ADDR);

ConnectStatus = connect(TCPSockID,

(struct sockaddr *)&ServerAddr,

sizeof(struct sockaddr_in));

if (ConnectStatus == 0) {

// Do something...

}

closesocket(TCPSockID);

OS_Delay(50);

}

116 CHAPTER 5 Socket interface

5.1.5 gethostbyname()

Description

Resolve a host name into an IP address.

Prototype

struct hostent * gethostbyname (char * name);

Parameter

Return value

On success, a pointer to a hostent structure is returned. Refer to Structure hostent

on page 140 for detailed information about the hostent structure.

On failure, it returns NULL.

Additional information

The function is called with a string containing the host name to be resolved as a fully-

qualified domain name (for example, myhost.mydomain.com).

Example

static void _DNSClient() {

struct hostent *pHostEnt;

char **ps;

char **ppAddr;

// Wait until link is up.

while (IP_IFaceIsReady() == 0) {

OS_Delay(100);

}

while(1) {

pHostEnt = gethostbyname("www.segger.com");

if (pHostEnt == NULL) {

printf("Could not resolve host addr.\n");

break;

}

printf("h_name: %s\n", pHostEnt->h_name);

// Show aliases

ps = pHostEnt->h_aliases;

for (;;) {

char * s;

s = *ps++;

if (s == NULL) {

break;

}

printf("h_aliases: %s\n", s);

}

// Show IP addresses

ppAddr = pHostEnt->h_addr_list;

for (;;) {

U32 IPAddr;

char * pAddr;

char ac[16];

pAddr = *ppAddr++;

if (pAddr == NULL) {

break;

}

Parameter Description

name [OUT] Host name.

Table 5.6: gethostbyname() parameter list

117

IPAddr = *(U32*)pAddr;

IP_PrintIPAddr(ac, IPAddr, sizeof(ac));

printf("IP Addr: %s\n", ac);

}

118 CHAPTER 5 Socket interface

5.1.6 getpeername()

Description

Fills the passed structure sockaddr with the IP addressing information of the con-

nected host.

Prototype

int getpeername ( long Socket,

struct sockaddr * pAddr,

struct int * pAddrLen );

Parameter

Return value

0 on success.

-1 on failure.

Additional information

Refer to Structure sockaddr on page 137 for detailed information about the structure

sockaddr.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pAddr [OUT] A pointer to a structure of type sockaddr in which the IP

address information of the connected host should be stored.

pAddrLen [OUT] A pointer to an integer to store the length of socket address.

Table 5.7: getpeername() parameter list

119

5.1.7 getsockname()

Description

Returns the current name for the specified socket.

Prototype

int getsockname ( long Socket,

struct sockaddr * pAddr );

Parameter

Return value

0 on success.

-1 on failure.

Additional information

Refer to Structure sockaddr on page 137 for detailed information about the structure

sockaddr.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pAddr [OUT] A pointer to a structure of type sockaddr in which the IP

address information of the connected host should be stored.

Table 5.8: getsockname() parameter list

120 CHAPTER 5 Socket interface

5.1.8 getsockopt()

Description

Returns the options associated with a socket.

Prototype

int getsockopt ( long Socket,

int Level,

int Option,

void * pData,

int DataLen );

121

Parameter

Valid values for parameter Option

Return value

0 on success.

-1 on failure.

Additional information

getsockopt() retrieves the current value for a socket option associated with a

socket of any type, in any state, and stores the result in pData. Options can exist at

multiple protocol levels, but they are always present at the uppermost “socket” level.

Options affect socket operations, such as the packet routing.

Parameter Description

Socket [IN] A descriptor identifying a socket.

Level [IN] Compatibility parameter for setsockopt() and getsockopt().

Use symbol SOL_SOCKET.

Option [IN] The socket option which should be retrieved.

pData [OUT] A pointer to the buffer in which the value of the requested

option should be stored.

DataLen [IN] The size of the data buffer.

Table 5.9: getsockopt() parameter list

Value Description

Standard option flags.

SO_ACCEPTCONN Indicates that socket is in listen mode.

SO_DONTROUTE

Indicates that outgoing messages must bypass

the standard routing facilities. Instead, messages

are directed to the appropriate network interface

according to the network portion of the destina-

tion address.

SO_KEEPALIVE

Indicates that the periodic transmission of mes-

sages on a connected socket is enabled. If the

connected party fails to respond to these mes-

sages, the connection is considered broken.

SO_LINGER Indicates that linger on close is enabled.

SO_NOSLOWSTART Indicates that suppress slow start on this socket

is enabled.

SO_TIMESTAMP Indicates that the TCP timestamp option is

enabled.

embOS/IP socket options.

SO_ERROR Stores the latest socket error in pData and clears

the error in socket structure.

SO_MYADDR Stores the IP address of the used interface in

pData.

SO_RCVTIMEO Returns the timeout for recv(). A return value of

0 indicates that no timeout is set.

SO_NONBLOCK

Gets sockets blocking status. Allows the caller to

specify blocking or non-blocking IO that works

the same as the other Boolean socket options.

pData points to an integer value which will con-

tain a non-zero value to set non-blocking IO or a

0 value to reset non-blocking IO.

122 CHAPTER 5 Socket interface

The value associated with the selected option is returned in the buffer pData. The

integer pointed to by DataLen should originally contain the size of this buffer; on

return, it will be set to the size of the value returned. For SO_LINGER, this will be the

size of a LINGER structure. For most other options, it will be the size of an integer.

The application is responsible for allocating any memory space pointed to directly or

indirectly by any of the parameters it specified. If the option was never set with set-

sockopt(), then getsockopt() returns the default value for the option.

The option SO_ERROR returns 0 or the number of the socket error and clears the

socket error. The following table lists the socket errors.

Symbolic name Value Description

IP_ERR_SEND_PENDING 1 Packet to send is not sent yet.

IP_ERR_MISC -1 Miscellaneous errors that do not have a

specific error code.

IP_ERR_TIMEDOUT -2 Operation timed out.

IP_ERR_ISCONN -3 Socket is already connected.

IP_ERR_OP_NOT_SUPP -4 Operation not supported for selected

socket.

IP_ERR_CONN_ABORTED -5 Connection was aborted.

IP_ERR_WOULD_BLOCK -6

Socket is in non-blocking state and the

current operation would block the socket

if not in non-blocking state.

IP_ERR_CONN_REFUSED -7 Connection refused by peer.

IP_ERR_CONN_RESET -8 Connection has been reset.

IP_ERR_NOT_CONN -9 Socket is not connected.

IP_ERR_ALREADY -10 Socket already is in the requested state.

IP_ERR_IN_VAL -11 Passed value for configuration is not

valid.

IP_ERR_MSG_SIZE -12 Message is too big to send.

IP_ERR_PIPE -13 Socket is not in the correct state for this

operation.

IP_ERR_DEST_ADDR_REQ -14 Destination addr. has not been specified.

IP_ERR_SHUTDOWN -15

Connection has been closed as soon as

all data has been received upon a FIN

request.

IP_ERR_NO_PROTO_OPT -16 Unknown socket option for setsockopt()

or getsockopt().

IP_ERR_NO_MEM -18 Not enough memory in the memory pool.

IP_ERR_ADDR_NOT_AVAIL -19 No known path to send to the specified

addr.

IP_ERR_ADDR_IN_USE -20

Socket already has a connection to this

addr. and port or is already bound to this

addr.

IP_ERR_IN_PROGRESS -22 Operation is still in progress.

IP_ERR_NO_BUF -23 No internal buffer was available.

IP_ERR_NOT_SOCK -24 Socket has not been opened or has

already been closed

IP_ERR_FAULT -25 Generic error for a failed operation.

IP_ERR_NET_UNREACH -26 No path to the desired network available.

IP_ERR_PARAM -27 Invalid parameter to function.

IP_ERR_LOGIC -28 Logical error that should not have hap-

pened.

IP_ERR_NOMEM -29 System error: No memory for requested

operation.

Table 5.10: embOS/IP socket error types

123

IP_ERR_NOBUFFER -30 System error: No internal buffer avail-

able for the requested operation.

IP_ERR_RESOURCE -31 System error: Not enough free resources

available for the requested operation.

IP_ERR_BAD_STATE -32 Socket is in an unexpected state.

IP_ERR_TIMEOUT -33 Requested operation timed out.

IP_ERR_NO_ROUTE -36 Net error: Destination is unreachable.

Symbolic name Value Description

Table 5.10: embOS/IP socket error types

124 CHAPTER 5 Socket interface

5.1.9 listen()

Description

Prepares the socket to accept connections.

Prototype

int listen ( long Socket,

int Backlog );

Parameter

Return value

On success 0.

On failure, it returns -1.

Additional information

The listen() call applies only to sockets of type SOCK_STREAM. If a connection

request arrives when the queue is full, the client will receive an error with an indica-

tion of ECONNREFUSED.

Example

/*********************************************************************

* _ListenAtTcpAddr

* Function description

* Starts listening at the given TCP port.

static int _ListenAtTcpAddr(U16 Port) {

int Sock;

struct sockaddr_in Addr;

Sock = socket(AF_INET, SOCK_STREAM, 0);

memset(&Addr, 0, sizeof(Addr));

Addr.sin_family = AF_INET;

Addr.sin_port = htons(Port);

Addr.sin_addr.s_addr = INADDR_ANY;

bind(Sock, (struct sockaddr *)&Addr, sizeof(Addr));

listen(Sock, 1);

return Sock;

}

Parameter Description

Socket [IN] Socket descriptor of an unconnected socket.

Backlog [IN] Backlog for incoming connections. Defines the maximum length

of the queue of pending connections.

Table 5.11: listen() parameter list

125

5.1.10 recv()

Description

Receives data from a connected socket.

Prototype

int recv ( long Socket,

char * pRecv,

int Length,

int Flags );

Parameter

Valid values for parameter Flag

Return value

If no error occurs, recv() returns the number of bytes received. If the connection has

been gracefully closed, the return value is zero. Otherwise, -1 is returned, and a spe-

cific error code can be retrieved by calling getsockopt(). Refer to getsockopt() on

page 120 for detailed information.

Additional information

If a message is too long to fit in the supplied buffer, excess bytes may be discarded

depending on the type of socket the message is received from. Refer to connect() on

page 114 for more information about the different types of sockets.

You can only use the recv() function on a connected socket. To receive data on a

socket, whether it is in a connected state or not refer to recvfrom() on page 126.

If no messages are available at the socket and the socket is blocking, the receive call

waits for a message to arrive. If the socket is non-blocking (refer to setsockopt() on

page 132 for more information), –1 is returned.

You can use the select() function to determine when more data arrives.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pRecv [OUT] A pointer to a buffer for incoming data.

Length [IN] The length of buffer pRecv in bytes.

Flags [IN] OR-combination of one or more of the following valid values.

Table 5.12: recv() parameter list

Value Description

MSG_PEEK

“Peek” at the data present on the socket; the data

are returned, but not consumed, so that a subse-

quent receive operation will see the same data.

126 CHAPTER 5 Socket interface

5.1.11 recvfrom()

Description

Receives a datagram and stores the source address.

Prototype

int recvfrom ( long Socket,

char * pRecv,

int Length,

int Flags,

struct sockaddr * pAddr,

int * pAddrLen );

Parameter

Valid values for parameter Flags

Return value

The number of bytes received or -1 if an error occurred.

Additional information

If pAddr is not a NULL pointer, the source address of the message is filled in. pAd-

drLen is a value-result parameter, initialized to the size of the buffer associated with

pAddr, and modified on return to indicate the actual size of the address stored there.

If a message is too long to fit in the supplied buffer, excess bytes may be discarded

depending on the type of socket the message is received from. Refer to socket() on

page 135 for more information about the different types of sockets.

If no messages are available at the socket and the socket is blocking, the receive call

waits for a message to arrive. If the socket is non-blocking (refer to setsockopt() on

page 132 for more information), –1 is returned.

You can use the select() function to determine when more data arrives.

Parameter Description

Socket [IN] A socket descriptor of a socket.

pRecv [OUT] A pointer to a buffer for incoming data.

Length [IN] Specifies the size of the buffer pRecv in bytes.

Flags [IN] OR-combination of one or more of the values listed in the table

below.

pAddr

[OUT] An optional pointer to a buffer where the address of the con-

necting entity is stored. The format of the address depends on the

defined address family which was defined when the socket was cre-

ated.

pAddrLen

[IN/OUT] An optional pointer to an integer where the length of the

received address is stored. Just like the format of the address, the

length of the address depends on the defined address family.

Table 5.13: recvfrom() parameter list

Value Description

MSG_PEEK

“Peek” at the data present on the socket; the data

are returned, but not consumed, so that a subse-

quent receive operation will see the same data.

127

5.1.12 select()

Description

Examines the socket descriptor sets whose addresses are passed in readfds,

writefds, and exceptfds to see if some of their descriptors are ready for reading,

ready for writing or have an exception condition pending.

Prototype

int select ( IP_FD_set * readfds,

IP_FD_set * writefds,

IP_FD_set * exceptfds;

long tv );

Parameter

Return value

Returns a non-negative value on success. A positive value indicates the number of

ready descriptors in the descriptor sets. 0 indicates that the time limit specified by tv

expired. On failure, select() returns -1 and the descriptor sets are not changed.

Additional information

On return, select() replaces the given descriptor sets with subsets consisting of

those descriptors that are ready for the requested operation. The total number of

ready descriptors in all the sets is returned. Any of readfds, writefds, and except-

fds may be given as NULL pointers if no descriptors are of interest. Selecting true for

reading on a socket descriptor upon which a listen() call has been performed indi-

cates that a subsequent accept() call on that descriptor will not block.

In the standard Berkeley UNIX Sockets API, the descriptor sets are stored as bit

fields in arrays of integers. This works in the UNIX environment because under UNIX

socket descriptors are file system descriptors which are guaranteed to be small inte-

gers that can be used as indexes into the bit fields. In embOS/IP, socket descriptors

are pointers and thus a bit field representation of the descriptor sets is not feasible.

Because of this, the embOS/IP API differs from the Berkeley standard in that the

descriptor sets are represented as instances of the following structure:

typedef struct IP_FD_SET { // The select socket array manager

unsigned fd_count; // how many are SET?

long fd_array[FD_SETSIZE]; // an array of SOCKETs

} IP_fd_set;

Instead of a socket descriptor being represented in a descriptor set via an indexed

bit, an embOS/IP socket descriptor is represented in a descriptor set by its presence

in the fd_array field of the associated IP_FD_SET structure. Despite this non-stan-

dard representation of the descriptor sets themselves, the following standard entry

points are provided for manipulating such descriptor sets: IP_FD_ZERO (&fdset) ini-

tializes a descriptor set fdset to the null set. IP_FD_SET(fd, &fdset) includes a

particular descriptor, fd, in fdset. IP_FD_CLR(fd, &fdset) removes fd from fdset.

IP_FD_ISSET(fd, &fdset) is nonzero if fd is a member of fdset, zero otherwise.

These entry points behave according to the standard Berkeley semantics.

Parameter Description

readfds

See below.

writefds

exceptfds

Table 5.14: select() parameter list

128 CHAPTER 5 Socket interface

You should be aware that the value of FD_SETSIZE defines the maximum number of

descriptors that can be represented in a single descriptor set. The default value of

FD_SETSIZE is 12. This value can be increased in the source code version of embOS/

IP to accommodate a larger maximum number of descriptors at the cost of increased

processor stack usage.

Another difference between the Berkeley and embOS/IP select() calls is the repre-

sentation of the timeout parameter. Under Berkeley Sockets, the timeout parameter

is represented by a pointer to a structure. Under embOS/IP sockets, a timeout is

specified by the tv parameter, which defines the maximum number of seconds that

should elapse before the call to select() returns. A tv parameter equal to 0 implies

that select() should return immediately (effectively a poll of the sockets in the

descriptor sets). A tv parameter equal to -1 implies that select() blocks forever

unless one of its descriptors becomes ready.

The final difference between the Berkeley and embOS/IP versions of select() is the

absence in the embOS/IP version of the Berkeley width parameter. The width param-

eter is of use only when descriptor sets are represented as bit arrays and was thus

deleted in the embOS/IP implementation.

Note: Under rare circumstances, select() may indicate that a descriptor is

ready for writing when in fact an attempt to write would block. This can happen if

system resources necessary for a write are exhausted or otherwise unavailable. If an

application deems it critical that writes to a file descriptor not block, it should set the

descriptor for non-blocking I/O. Refer to setsockopt() on page 132 for detailed infor-

mation.

Example

static void _Client() {

long Socket;

struct sockaddr_in Addr;

IP_fd_set readfds;

char RecvBuffer[1472]

int r;

while (IP_IFaceIsReady() == 0) {

OS_Delay(100);

}

Restart:

Socket = socket(AF_INET, SOCK_DGRAM, 0); // Open socket

Addr.sin_family = AF_INET;

Addr.sin_port = htons(2222);

Addr.sin_addr.s_addr = INADDR_ANY;

r = bind(Socket, (struct sockaddr *)&Addr, sizeof(Addr));

if (r == -1){

socketclose(Socket);

OS_Delay(1000);

goto Restart;

}

while(1) {

IP_FD_ZERO(&readfds); // Clear the set

IP_FD_SET(Socket, &readfds); // Add descriptor to the set

r = select(&readfds, NULL, NULL, 5000); // Check for activity.

if (r <= 0) {

continue; // No socket activity or error detected

}

if (IP_FD_ISSET(Socket, &readfds)) {

IP_FD_CLR(Socket, &readfds); // Remove socket from set

r = recvfrom(Socket, RecvBuffer, sizeof(RecvBuffer), 0, NULL, NULL);

if (r == -1){

socketclose(Socket)

goto Restart;

}

129

OS_Delay(100);

}

130 CHAPTER 5 Socket interface

5.1.13 send()

Description

Sends data to a connected socket.

Prototype

int send ( long Socket,

char * pSend,

int Length,

int Flags );

Parameter

Valid values for parameter Flags

Return value

The total number of bytes which were sent or -1 if an error occurred.

Additional information

send() may be used only when the socket is in a connected state. Refer to sendto()

on page 131 for information about sending data to a non-connected socket.

If no messages space is available at the socket to hold the message to be transmit-

ted, then send() normally blocks, unless the socket has been placed in non-blocking

I/O mode.

MSG_DONTROUTE is usually used only by diagnostic or routing programs.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pSend [IN] A pointer to a buffer of data which should be sent.

Length [IN] The length of the message which should be sent.

Flags [IN] OR-combination of one or more of the valid values listed in the

table below.

Table 5.15: send() parameter list

Value Description

MSG_DONTROUTE Specifies that the data should not be subject to

routing.

131

5.1.14 sendto()

Description

Sends data to a specified address.

Prototype

int sendto ( long Socket,

char * pSend,

int Length,

int Flags,

struct sockaddr * pAddr,

int ToLen );

Parameter

Valid values for parameter Flags

Return value

The total number of bytes which were sent or -1 if an error occurred.

Additional information

In contrast to send(), sendto() can be used at any time. The connection state is in

which case the address of the target is given by the pAddr parameter.

Parameter Description

Socket [IN] A descriptor identifying a socket.

pSend [IN] A pointer to a buffer of data which should be sent.

Length [IN] The length of the message which should be sent.

Flags [IN] OR-combination of one or more of the valid values listed in the

table below.

pAddr

[IN] An optional pointer to a buffer where the address of the con-

nected entity is stored. The format of the address depends on the

defined address family which was defined when the socket was cre-

ated.

ToLen [IN] The size of the address in pAddr.

Table 5.16: sendto() parameter list

Value Description

MSG_DONTROUTE Specifies that the data should not be subject to

routing.

132 CHAPTER 5 Socket interface

5.1.15 setsockopt()

Description

Sets a socket option.

Prototype

int setsockopt ( long Socket,

int Level,

int Option,

void * pData,

int DataLen );

Parameter

Valid values for parameter Option

Parameter Description

Socket [IN] A descriptor identifying a socket.

Level [IN] Compatibility parameter for setsockopt() and getsockopt(). Use

symbol SOL_SOCKET.

Option [IN] The socket option for which the value is to be set.

pData [IN] A pointer to the buffer in which the value for the requested

option is supplied.

DataLen [IN] The size of the pData buffer.

Table 5.17: setsocketopt() parameter list

Value Description

Standard option flags.

SO_DONTROUTE

Outgoing messages should bypass the standard

routing facilities. Instead, messages are directed

to the appropriate network interface according to

the network portion of the destination address.

By default, this socket option is disabled.

SO_KEEPALIVE

Enable periodic transmission of messages on a

connected socket. If the connected party fails to

respond to these messages, the connection is

considered broken.

By default, this socket option is enabled.

SO_LINGER

Controls the action taken when unsent messages

are queued on a socket and a closesocket() is

performed. Refer to closesocket() on page 113

for detailed information about the linger option.

By default, this socket option is disabled.

SO_TIMESTAMP Enable the TCP timestamp option.

By default, this socket option is disabled.

embOS/IP socket options.

SO_CALLBACK

Sets zero-copy callback routine. Refer to TCP

zero-copy interface on page 143 for detailed

information.

SO_RCVTIMEO

Sets a timeout for recv(). This changes the

behavior of recv(). recv() is by default a block-

ing function which only returns if data has been

received. If a timeout is set recv() will return in

case of data reception or timeout.

By default, this socket option is disabled.

133

Return value

0 on success

Example

void _EnableKeepAlive(long sock) {

int v = 1;

setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &v, sizeof(v));

}

SO_NONBLOCK

Sets socket blocking status. Allows the caller to

specify blocking or non-blocking IO that works

the same as the other Boolean socket options.

pData points to an integer value which will con-

tain a non-zero value to set non-blocking IO or a

0 value to reset non-blocking IO.

By default, this socket option is disabled.

Value Description

134 CHAPTER 5 Socket interface

5.1.16 shutdown()

Description

Disables sends or receives on a socket.

Prototype

int shutdown( long Socket,

int Mode );

Parameter

Return value

Returns 0 on success.

On failure, it returns -1.

Additional information

A shutdown() call causes all or part of a full-duplex connection on the socket associ-

ated with Socket to be shut down. If Mode is 0, then further receives will be disal-

lowed. If Mode is 1, then further sends will be disallowed. If Mode is 2, then further

sends and receives will be disallowed. The shutdown function does not block regard-

less of the SO_LINGER setting on the socket.

Parameter Description

Socket [IN] A descriptor identifying a socket.

Mode [IN] Indicator which part of communication should be disabled.

Refer to additional information below.

Table 5.18: shutdown() parameter list

135

5.1.17 socket()

Description

Creates a socket. A socket is an endpoint for communication.

Prototype

long socket ( int Domain,

int Type,

int Proto );

Parameter

Valid values for parameter Domain

Valid values for parameter Type

Return value

A non-negative descriptor on success.

On failure, it returns -1.

Additional information

The Domain parameter specifies a communication domain within which communica-

tion will take place; the communication domain selects the protocol family which

should be used. The protocol family generally is the same as the address family for

the addresses supplied in later operations on the socket.

A SOCK_STREAM socket provides sequenced, reliable, two-way connection based byte

streams. A SOCK_DGRAM socket supports datagrams (connectionless, unreliable mes-

sages of a fixed - typically small - maximum length).

Sockets of type SOCK_STREAM are full-duplex byte streams, similar to UNIX pipes. A

stream socket must be in a connected state before it can send or receive data.

A connection to another socket is created with a connect() call. Once connected,

data can be transferred using send() and recv() calls. When a session has been

completed, a closesocket() should be performed.

The communications protocols used to implement a SOCK_STREAM ensure that data is

not lost or duplicated. If a piece of data (for which the peer protocol has buffer

space) cannot be successfully transmitted within a reasonable length of time, then

the connection is considered broken and calls will return -1 which indicates an error.

The protocols optionally keep sockets “warm” by forcing transmissions roughly every

minute in the absence of other activity. An error is then indicated if no response can

be elicited on an otherwise idle connection for a extended period (such as five min-

utes).

Parameter Description

Domain [IN] Protocol family which should be used.

Type [IN] Specifies the type of the socket.

Proto [IN] Specifies the protocol which should be used with the socket.

Must be set to zero.

Table 5.19: socket() parameter list

Value Description

AF_INET IPv4 - Internet protocol version 4

Value Description

SOCK_STREAM Stream socket

SOCK_DGRAM Datagram socket

136 CHAPTER 5 Socket interface

SOCK_DGRAM sockets allow sending of datagrams to correspondents named in

sendto() calls. Datagrams are generally received with recvfrom(), which returns

the next datagram with its return address.

The operation of sockets is controlled by socket-level options. The getsockopt() and

setsockopt() functions are used to get and set options. Refer to getsockopt() on

page 120 and setsockopt() on page 132 for detailed information.

137

5.2 Socket data structures

5.2.1 Structure sockaddr

Description

This structure holds socket address information for many types of sockets.

Prototype

struct sockaddr {

U16 sa_family;

char sa_data[14];

};

Additional information

The structure sockaddr is mostly used as function parameter. To deal with struct

sockaddr, a parallel structure struct sockaddr_in is implemented. The structure

sockaddr_in is the same size as structure sockaddr, so that a pointer can freely be

casted from one type to the other. Refer to Structure sockaddr_in on page 138 for

more information and an example.

Member Description

sa_family Address family. Normally AF_INET.

sa_data The character array sa_data contains the destination address and

port number for the socket.

Table 5.20: Structure sockaddr member list

138 CHAPTER 5 Socket interface

5.2.2 Structure sockaddr_in

Description

Structure for handling internet addresses.

Prototype

struct sockaddr_in {

short sin_family;

unsigned short sin_port;

struct in_addr sin_addr;

char sin_zero[8];

};

Example

Refer to connect() on page 114 for an example.

Member Description

sin_family Address family. Normally AF_INET.

sin_port Port number for the socket.

sin_addr Structure of type in_addr. The structure represents a 4-byte

number that represents one digit in an IP address per byte.

sin_zero sin_zero member is unused.

Table 5.21: Structure sockaddr_in member list

139

5.2.3 Structure in_addr

Description

4-byte number that represents one digit in an IP address per byte.

Prototype

struct in_addr {

unsigned long s_addr;

};

Member Description

s_addr Number that represents one digit in an IP address per byte.

Table 5.22: Structure in_addr member list

140 CHAPTER 5 Socket interface

5.2.4 Structure hostent

Description

The hostent structure is used by functions to store information about a given host,

such as host name, IPv4 address, and so on.

Prototype

struct hostent {

char * h_name;

char ** h_aliases;

int h_addrtype;

int h_length;

char ** h_addr_list;

};

Member Description

h_name Official name of the host.

h_aliases Alias list.

s_addrtype Host address type.

h_length Length of the address.

s_addr_list List of addresses from the name server.

Table 5.23: Structure in_addr member list

141

5.3 Error codes

The following table contains a list of generic error codes, generally full success is 0.

Definite errors are negative numbers, and indeterminate conditions are positive

numbers.

Symbolic name Value Description

Programming errors

IP_ERR_PARAM -10 Bad parameter.

IP_ERR_LOGIC -11 Sequence of events that shouldn't hap-

pen.

System errors

IP_ERR_NOMEM -20 malloc() or calloc() failed.

IP_ERR_NOBUFFER -21 Run out of free packets.

IP_ERR_RESOURCE -22 Run out of other queue-able resource.

IP_ERR_BAD_STATE -23 TCP layer error.

IP_ERR_TIMEOUT -24 Timeout error on TCP layer.

Networking errors

IP_ERR_BAD_HEADER -32 Bad header at upper layer (for upcalls).

IP_ERR_NO_ROUTE -33 Can not find a reasonable next IP hop.

Networking errors

IP_ERR_SEND_PENDING 1 Packet queued pending an ARP reply.

IP_ERR_NOT_MINE 2 Packet was not of interest (upcall reply).

Table 5.24: embOS/IP error types

142 CHAPTER 5 Socket interface

143

Chapter 6

TCP zero-copy interface

The TCP protocol can be used via socket functions or the TCP zero-copy interface

which is described in this chapter.

144 CHAPTER 6 TCP zero-copy interface

6.1 TCP zero-copy

This section documents an optional extension to the Sockets layer, the TCP zero-copy

API. The TCP zero-copy API is intended to assist the development of higher-perfor-

mance embedded network applications by allowing the application direct access to

the TCP/IP stack packet buffers. This feature can be used to avoid the overhead of

having the stack copy data between application-owned buffers and stack-owned buff-

ers in send() and recv(), but the application has to fit its data into, and accept its

data from, the stack buffers.

The TCP zero-copy API is small because it is simply an extension to the existing

Sockets API that provides an alternate mechanism for sending and receiving data on

a socket. The Sockets API is used for all other operations on the socket.

6.1.1 Allocating, freeing and sending packet buffers

The two functions for allocating and freeing packet buffers are straightforward

requests:

IP_TCP_Alloc() allocates a packet buffer from the pool of packet buffers on the

stack and IP_TCP_Free() frees a packet buffer. Applications using the TCP zero-copy

API are responsible for allocating packet buffers for use in sending data, as well as

for freeing buffers that have been used to receive data and those that the application

has allocated but decided not to use for sending data. As these packet buffers are a

limited resource, it is important that applications free them promptly when they are

no longer of use.

The functions for sending data, IP_TCP_Send() and IP_TCP_SendAndFree(), send a

packet buffer of data using a socket. The TCP zero-copy interface supports two differ-

ent approaches to send and free a packet. One approach is that the stack frees the

packet independent from the success of sending the packet. Therefor,

IP_TCP_SendAndFree() is called to send and free the packet. It frees the packet

independent from the success of the send operation. The other approach is that

IP_TCP_Send() is called. In this case it is the responsibility of the application to free

the packet. Depending on the return value the application can decide if

IP_TCP_Free() should be called to free the packet.

6.1.2 Callback function

Applications that use the TCP Zero-copy API for receiving data must include a call-

back function for acceptance of received packets, and must register the callback

function with the socket using the setsockopt() sockets function with the

SO_CALLBACK option name. The callback function, once registered, receives not only

received data packets, but also connection events that result in socket errors.

145

6.2 Sending data with the TCP zero-copy API

To send data with the TCP zero-copy API, you should proceed as follow:

1. Allocating a packet buffer

2. Filling the allocated buffer

3. Sending the packet

The following section describes the procedure for allocating a packet buffer, sending

data, and freeing the packet buffer step by step.

6.2.1 Allocating a packet buffer

The first step in using the TCP zero-copy API to send data is to allocate a packet

buffer from the stack using the IP_TCP_Alloc() function. This function takes the

maximum length of the data you intend to send in the buffer as argument and

returns a pointer to an IP_PACKET structure.

IP_PACKET * pPacket;

U32 DataLen; // Amount of data to send

DataLen = 512; // Should indicate amount of data to send

pPacket = IP_TCP_Alloc(DataLen);

if (pPacket == NULL) {

// Error, could not allocate packet buffer

}

This limits how much data you can send in one call using the TCP zero-copy API, as

the data sent in one call to IP_TCP_Send() must fit in a single packet buffer. The

actual limit is determined by the big packet buffer size, less 68 bytes for protocol

headers. If you try to request a larger buffer than this, IP_TCP_Alloc() returns

NULL to indicate that it cannot allocate a sufficiently large buffer.

6.2.2 Filling the allocated buffer with data

Having allocated the packet buffer, you now fill it with the data to send. The function

IP_TCP_Alloc() has initialized the returned IP_PACKET pPacket and so pPacket-

>pData points to where you can start depositing data.

6.2.3 Sending the packet

Finally, you send the packet by giving it back to the stack using the function

IP_TCP_Send().

e = IP_TCP_Send(socket, pPacket);

if (e < 0) {

IP_TCP_Free(pPacket);

}

This function sends the packet over TCP, or returns an error. If its return value is less

than zero, it has not accepted the packet and the application has to decide either to

free the packet or to retain it for sending later. Use IP_TCP_SendAndFree() if the

packet should be freed automatically in any case.

146 CHAPTER 6 TCP zero-copy interface

6.3 Receiving data with the TCP zero-copy API

To receive data with the TCP zero-copy API, you should proceed as follow:

1. Writing a callback function

2. Registering the callback function

6.3.1 Writing a callback function

Using the TCP zero-copy API for receiving data requires the application developer to

write a callback function that the stack can use to inform the application of received

data packets and other socket events. This function is expected to conform to the fol-

lowing prototype:

int rx_callback(long Socket, IP_PACKET * pPacket, int code);

The stack calls this function when it has received a data packet or other event to

report for a socket. The parameter Socket identifies the socket. The parameter

pPacket passes a pointer to the packet buffer (if there is a packet buffer). If pPacket

is not NULL, it is a pointer to a packet buffer containing received data for the socket.

pPacket->pData points to the start of the received data, and pPacket->NumBytes

indicates the number of bytes of received data in this buffer.

The parameter code passes an error event (if there is an error to report). If code is

not 0, it is a socket error indicating that an error or other event has occurred on the

socket. Typical nonzero values are ESHUTDOWN and ECONNRESET. ESHUTDOWN defines

that the connected peer has closed its end of the connection and sends no more data.

ECONNRESET defines that the connected peer has abruptly closed its end of the con-

nection and neither sends nor receives more data.

Returned values

The callback function may return one of the following values:

Note: The callback function is called from the stack and is expected to return

promptly. Some of the places where the stack calls the callback function require that

the data structures on the stack remain consistent through the callback, so the call-

back function must not call back into the stack except to call IP_TCP_Free().

6.3.2 Registering the callback function

The application must also inform the stack of the callback function. setsockopt()

function provides an additional socket option, SO_CALLBACK, which should be used for

this purpose once the socket has been created. The following code fragment illus-

trates the use of this option to register a callback function named RxUpcall() on the

socket Socket:

setsockopt(Socket, SOL_SOCKET, SO_CALLBACK, (void *)RxUpcall, 0);

The function setsockopt() is described in setsockopt() on page 132.

Symbolic Nume

rical Description

IP_OK 0 Data handled, packet can be freed.

IP_OK_KEEP_PACKET 1

Data will be handled by application later, the

stack should NOT free the packet. This will be

done by the application at a later time when the

data has been handled and the packet is no

longer needed.

Table 6.1: embOS/IP TCP zero-copy - Valid return values for the receive callback function

147

6.4 API functions

Function Description

IP_TCP_Alloc() Allocates a packet buffer.

IP_TCP_Free() Frees a packet buffer.

IP_TCP_Send() Sends a packet.

IP_TCP_SendAndFree() Sends and frees a packet.

Table 6.2: embOS/IP TCP zero-copy API function overview

148 CHAPTER 6 TCP zero-copy interface

6.4.1 IP_TCP_Alloc()

Description

Allocates a packet buffer large enough to hold datasize bytes of TCP data, plus TCP,

IP and MAC headers.

Prototype

IP_PACKET * IP_TCP_Alloc (int datasize);

Parameter

Return value

Success: Returns a pointer to the allocated buffer.

Error: NULL

Additional information

This function must be called to allocate a buffer for sending data via IP_TCP_Send().

It returns the allocated packet buffer with its pPacket->pData field set to where the

application must deposit the data to be sent.

This datasize limits how much data that you can send in one call using the TCP zero-

copy API, as the data sent in one call to IP_TCP_Send() must fit in a single packet

buffer, with the TCP, IP, and lower-layer headers that the stack needs to add in order

to send the packet.

The actual limit is determined by the big packet buffer size (normally 1536 bytes).

Refer to IP_AddBuffers() on page 45 for more information about defining buffer

sizes. If you try to request a larger buffer than this, IP_TCP_Alloc() returns NULL to

indicate that it cannot allocate a sufficiently-large buffer.

Example

IP_PACKET * pPacket;

U32 DataLen; // Amount of data to send

DataLen = 1024; // Should indicate amount of data to send

pPacket = IP_TCP_Alloc(DataLen);

if (pPacket == NULL) {

// Error, could not allocate packet buffer

}

Parameter Description

datasize [IN] Length of the data which should be sent.

Table 6.3: IP_TCP_Alloc() parameter list

149

6.4.2 IP_TCP_Free()

Description

Frees a packet buffer allocated by IP_TCP_Alloc().

Prototype

void IP_TCP_Free ( IP_PACKET * pPacket );

Parameter

Parameter Description

pPacket [IN] Pointer to the IP_Packet structure.

Table 6.4: IP_TCP_Free() parameter list

150 CHAPTER 6 TCP zero-copy interface

6.4.3 IP_TCP_Send()

Description

Sends a packet buffer on a socket.

Prototype

int IP_TCP_Send ( U32 s,

IP_PACKET * pPacket );

Parameter

Return value

0 The packet was sent successfully.

<0 The packet was not accepted by the stack. The application must re-send the

packet using a call to IP_TCP_Send(), or free the packet using IP_TCP_Free().

>0 The packet has been accepted and queued on the socket but has not yet been

transmitted.

Additional information

Applications using the TCP zero-copy API are responsible for allocating packet buffers

for use in sending data, as well as for freeing buffers that have been used to receive

data and those that the application has allocated but decided not to use for sending

data. As these packet buffers are a limited resource, it is important that applications

free them promptly when they are no longer of use.

Packets have to be freed after processing. The TCP zero-copy interface supports two

different approaches to free a packet. One approach is that the stack frees the

packet independent from the success of sending the packet. Therefor,

IP_TCP_SendAndFree() is called to send the packet and free the packet. It frees the

packet independent from the success of the send operation. The other approach is

that IP_TCP_Send() is called. In this case it is the responsibility application program-

mer to free the packet. Depending on the return value the application programmer

can decide if IP_TCP_Free() should be called to free the packet.

Parameter Description

s[IN] Socket descriptor.

pPacket [IN] Pointer to a packet buffer.

Table 6.5: IP_TCP_Send() parameter list

151

6.4.4 IP_TCP_SendAndFree()

Description

Sends a packet buffer on a socket.

Prototype

int IP_TCP_SendAndFree ( U32 s,

IP_PACKET * pPacket );

Parameter

Return value

0 The packet was sent successfully.

<0 The packet was not accepted by the stack.

>0 The packet has been accepted and queued on the socket but has not yet been

transmitted.

Additional information

Applications using the TCP zero-copy API are responsible for allocating packet buffers

for use in sending data, as well as for freeing buffers that have been used to receive

data and those that the application has allocated but decided not to use for sending

data. As these packet buffers are a limited resource, it is important that applications

free them promptly when they are no longer of use.

IP_TCP_SendAndFree() frees packet pPacket after processing. It frees the packet

independent from the success of the send operation.

Parameter Description

s[IN] Socket descriptor.

pPacket [IN] Pointer to the IP_Packet structure.

Table 6.6: IP_TCP_Send() parameter list

152 CHAPTER 6 TCP zero-copy interface

153

Chapter 7

UDP zero-copy interface

The UDP transfer protocol can be used via socket functions or the zero-copy interface

which is described in this chapter.

154 CHAPTER 7 UDP zero-copy interface

7.1 UDP zero-copy

The UDP zero-copy API functions are provided for systems that do not need the over-

head of sockets. These routines impose a lower demand on CPU and system memory

requirements than sockets. However, they do not offer the portability of sockets.

UDP zero-copy API functions are intended to assist the development of higher-perfor-

mance embedded network applications by allowing the application direct access to

the TCP/IP stack packet buffers. This feature can be used to avoid the overhead of

having the stack copy data between application-owned buffers and stack-owned buff-

ers in sendto() and recvfrom(), but the application has to fit its data into, and

accept its data from, the stack buffers. Refer to embOS/IP UDP discover

(OS_IP_UDPDiscover.c / OS_IP_UDPDiscoverZeroCopy.c) on page 39 for detailed

dinformation about the UDP zero-copy example application.

7.1.1 Allocating, freeing and sending packet buffers

The two functions for allocating and freeing packet buffers are straightforward

requests:

IP_UDP_Alloc() allocates a packet buffer from the pool of packet buffers on the

stack and IP_UDP_Free() frees a packet buffer. Applications using the UDP zero-copy

API are responsible for allocating packet buffers for use in sending data, as well as

for freeing buffers that have been used to receive data and those that the application

has allocated but decided not to use for sending data. As these packet buffers are a

limited resource, it is important that applications free them promptly when they are

no longer of use.

The functions for sending data, IP_UDP_Send() and IP_UDP_SendAndFree(), send a

packet buffer of data using a port. The UDP zero-copy interface supports two differ-

ent approaches to send and free a packet. One approach is that the stack frees the

packet independent from the success of sending the packet. Therefor,

IP_UDP_SendAndFree() is called to send and free the packet. It frees the packet

independent from the success of the send operation. The other approach is that

IP_UDP_Send() is called. In this case it is the responsibility of the application to free

the packet. Depending on the return value the application can decide if

IP_UDP_Free() should be called to free the packet.

7.1.2 Callback function

Applications that use the UDP zero-copy API for receiving data must include a call-

back function for acceptance of received packets, and must register the callback

function with a port using the IP_UDP_Open() function. The callback function, once

registered, receives all matching data packets.

155

7.2 Sending data with the UDP zero-copy API

To send data with the UDP zero-copy API, you should proceed as follow:

1. Allocating a packet buffer

2. Filling the allocated buffer

3. Sending the packet

The following section describes the procedure for allocating a packet buffer, sending

data, and freeing the packet buffer step by step.

7.2.1 Allocating a packet buffer

The first step in using the UDP zero-copy API to send data is to allocate a packet

buffer from the stack using the IP_UDP_Alloc() function. This function takes the

maximum length of the data you intend to send in the buffer as argument and

returns a pointer to an IP_PACKET structure.

IP_PACKET * pPacket;

U32 DataLen; // Amount of data to send

DataLen = 512; // Should indicate amount of data to send

pPacket = IP_UDP_Alloc(DataLen);

if (pPacket == NULL) {

// Error, could not allocate packet buffer

}

This limits how much data you can send in one call using the UDP zero-copy API, as

the data sent in one call to IP_UDP_Send() must fit in a single packet buffer. The

actual limit is determined by the big packet buffer size, less typically 42 bytes for

protocol headers (14 bytes for Ethernet header, 20 bytes IP header, 8 bytes UDP

header). If you try to request a larger buffer than this, IP_UDP_Alloc() returns NULL

to indicate that it cannot allocate a sufficiently large buffer.

7.2.2 Filling the allocated buffer with data

Having allocated the packet buffer, you now fill it with the data to send. The function

IP_UDP_Alloc() has initialized the returned IP_PACKET pPacket and so pPacket-

>pData points to where you can start depositing data.

7.2.3 Sending the packet

Finally, you send the packet by giving it back to the stack using the function

IP_UDP_Send().

#define SRC_PORT 50020

#define DEST_PORT 50020

#define DEST_ADDR 0xC0A80101

e = IP_UDP_Send(0, DEST_ADDR, SRC_PORT, DEST_PORT, pPacket);

if (e < 0) {

IP_UDP_Free(pPacket);

}

This function sends the packet over UDP, or returns an error. If its return value is less

than zero, it has not accepted the packet and the application has to decide either to

free the packet or to retain it for sending later. Use IP_UDP_SendAndFree() if the

packet should be freed automatically in any case.

156 CHAPTER 7 UDP zero-copy interface

7.3 Receiving data with the UDP zero-copy API

To receive data with the UDP zero-copy API, you should proceed as follow:

1. Writing a callback function

2. Registering the callback function

7.3.1 Writing a callback function

Using the UDP zero-copy API for receiving data requires the application developer to

write a callback function that the stack can use to inform the application of received

data packets. This function is expected to conform to the following prototype:

int rx_callback(IP_PACKET * pPacket, void * pContext)

The stack calls this function when it has received a data packet for a port. The

parameter pPacket points to the packet buffer. The packet buffer contains the

received data for the socket. pPacket->pData points to the start of the received

data, and pPacket->NumBytes indicates the number of bytes of received data in this

buffer.

Returned values

The callback function may return one of the following values:

Note: The callback function is called from the stack and is expected to return

promptly. Some of the places where the stack calls the callback function require that

the data structures on the stack remain consistent through the callback, so the call-

back function must not call back into the stack except to call IP_UDP_Free().

7.3.2 Registering the callback function

The application must also inform the stack of the callback function. This is done by

calling the IP_UDP_Open() function. The following code fragment illustrates the use

of this option to register a callback function named RxUpcall() on the port 50020:

#define SRC_PORT 50020

#define DEST_PORT 50020

IP_UDP_Open(0L /* any foreign host */, SRC_PORT, DEST_PORT, RxUpCall, 0L /* any tag

*/);

The function IP_UDP_Open() is described in IP_UDP_Open() on page 166.

Symbolic Nume

rical Description

IP_OK 0 Data handled. embOS/IP will free the packet.

IP_OK_KEEP_PACKET 1

Data will be handled by application later, the

stack should NOT free the packet. This will be

done by the application at a later time when the

data has been handled and the packet is no

longer needed.

Table 7.1: embOS/IP UDP zero-copy - Valid return values for the receive callback function

UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
157
7.4 API functions
Function Description
IP_UDP_Alloc() Returns a pointer to a packet buffer big 
enough for the specified sizes.
IP_UDP_Close() Closes a UDP connection handle.
IP_UDP_FindFreePort() Returns a free local port number.
IP_UDP_Free() Frees the buffer which was used for a 
packet.
IP_UDP_GetDataPtr() Returns pointer to data contained in the 
received UDP packet.
IP_UDP_GetFPort() Extracts foreign port information from a 
UDP packet.
IP_UDP_GetLPort() Extracts local port information from a UDP 
packet.
IP_UDP_GetSrcAddr() Retrieves the IP address of the sender of 
the given UDP packet.
IP_UDP_Open() Creates a UDP connection handle.
IP_UDP_Send() Sends an UDP packet to a specified host.
IP_UDP_SendAndFree() Sends an UDP packet to a specified host 
and frees the packet.
Table 7.2: embOS/IP UDP zero-copy API function overview

158 CHAPTER 7 UDP zero-copy interface

7.4.1 IP_UDP_Alloc()

Description

Returns a pointer to a packet buffer big enough for the specified sizes.

Prototype

IP_PACKET * IP_UDP_Alloc( int NumBytes );

Parameter

Return value

Success: Returns a pointer to the allocated buffer.

Error: NULL

Additional information

Applications using the UDP zero-copy API are responsible for allocating packet buff-

ers for use in sending data, as well as for freeing buffers that have been used to

receive data and those that the application has allocated but decided not to use for

sending data. As these packet buffers are a limited resource, it is important that

applications free them promptly when they are no longer of use.

The UDP zero-copy interface supports two different approaches to free a packet. One

approach is that the stack frees the packet independent from the success of sending

the packet. Therefor, IP_UDP_SendAndFree() is called to send the packet and free

the packet. It frees the packet independent from the success of the send operation.

The other approach is that IP_UDP_Send() is called. In this case it is the responsibil-

ity application programmer to free the packet. Depending on the return value the

application programmer can decide if IP_UDP_Free() should be called to free the

packet.

Parameter Description

NumBytes [IN] Length of the data which should be sent.

Table 7.3: IP_UDP_Alloc() parameter list

159

7.4.2 IP_UDP_Close()

Description

Closes a UDP connection handle and removes the connection from demux table list of

connections and deallocates it.

Prototype

void IP_UDP_Close( IP_UDP_CONN Con );

Parameter

Parameter Description

Con [IN] UDP connection handle.

Table 7.4: IP_UDP_Close() parameter list

160 CHAPTER 7 UDP zero-copy interface

7.4.3 IP_UDP_FindFreePort()

Description

Obtains a random port number. that is suitable for use as the lport parameter in a

call to IP_UDP_Open().

Prototype

U16 IP_UDP_FindFreePort( void );

Return value

A usable port number in local endianess.

Additional information

The returned port number is suitable for use as the lport parameter in a call to

IP_UDP_Open(). Refer to IP_UDP_Open() on page 166 for more information.

IP_UDP_FindFreePort() avoids picking port numbers in the reserved range 0-1024,

or in the range 1025-1199, which may be used for server applications.

161

7.4.4 IP_UDP_Free()

Description

Frees the buffer which was used for a packet.

Prototype

void IP_UDP_Free( IP_PACKET * pPacket );

Parameter

Parameter Description

pPacket [IN] Pointer to a packet structure.

Table 7.5: IP_UDP_Free() parameter list

162 CHAPTER 7 UDP zero-copy interface

7.4.5 IP_UDP_GetDataPtr()

Description

Returns pointer to data contained in the received UDP packet.

Prototype

void * IP_UDP_GetDataPtr( const IP_PACKET * pPacket );

Parameter

Parameter Description

pPacket [IN] Pointer to a packet structure.

Table 7.6: IP_UDP_GetDataPtr() parameter list

163

7.4.6 IP_UDP_GetFPort()

Description

Extracts foreign port information from a UDP packet.

Prototype

U16 IP_UDP_GetFPort ( const IP_PACKET * pPacket );

Parameter

Parameter Description

pPacket [IN] Pointer to a packet structure.

Table 7.7: IP_UDP_GetFPort() parameter list

164 CHAPTER 7 UDP zero-copy interface

7.4.7 IP_UDP_GetLPort()

Description

Extracts local port information from a UDP packet.

Prototype

U16 IP_UDP_GetLPort ( const IP_PACKET * pPacket );

Parameter

Parameter Description

pPacket [IN] Pointer to a packet structure.

Table 7.8: IP_UDP_GetLPort() parameter list

165

7.4.8 IP_UDP_GetSrcAddr()

Description

Returns pointer to data contained in the received UDP packet.

Prototype

void IP_UDP_GetSrcAddr( const IP_PACKET * pPacket,

void * pSrcAddr,

int AddrLen );

Parameter

Parameter Description

pPacket [IN] Pointer to a packet structure.

pSrcAddr [IN] Pointer to a buffer to store the source address.

AddrLen [IN] Size of the buffer used to store the source address.

Table 7.9: IP_UDP_GetSrcAddr() parameter list

166 CHAPTER 7 UDP zero-copy interface

7.4.9 IP_UDP_Open()

Description

Creates a UDP connection handle to receive, and pass upwards, UDP packets that

match the parameters passed.

Prototype

IP_UDP_CONN IP_UDP_Open( IP_ADDR IPAddr,

U16 fport,

U16 lport,

int(*routine) (IP_PACKET *, void * pContext),

void * pContext );

Parameter

Return value

Success: Returns a pointer to the UDP connection handle.

Error: NULL

Additional information

The parameters IPAddr, fport, and lport, can be set to 0 as a wild card, which

enables the reception of broadcast datagrams. The callback handler function is called

with a pointer to a received datagram and a copy of the data pointer which is passed

to IP_UDP_Open(). This can be any data the programmer requires, such as a pointer

to another function, or a control structure to aid in demultiplexing the received UDP

packet.

The returned handle is used as parameter for IP_UDP_Close() only. If

IP_UDP_Close() is not called, there is no need to safe the return value.

Parameter Description

IPAddr [IN] IP address.

fport [IN] Foreign port.

lport [IN] Local port.

(*routine) [IN] Callback function which is called when a UDP packet is

received.

pContext [IN/OUT] Application defined context pointer.

Table 7.10: IP_UDP_Open() parameter list

167

7.4.10 IP_UDP_Send()

Description

Send an UDP packet to a specified host.

Prototype

int IP_UDP_Send( int IFace,

IP_ADDR FHost,

U16 fport,

U16 lport,

IP_PACKET * pPacket );

Parameter

Return value

On success: 0

On error: Non-zero error code

Additional information

The packet pPacket has to be allocated by calling IP_UDP_Alloc(). Refer to

IP_UDP_Alloc() on page 158 for detailed information.

If you expect to get any response to this packet you should have opened a UDP con-

nection prior to calling IP_UDP_Send(). Refer to IP_UDP_Open() on page 166 for

more information about creating an UDP connection.

IP_UDP_Send() does not free the packet after sending. It is the responsibility of the

application programmer to free the packet. Depending on the return value the appli-

cation programmer can decide if IP_UDP_Free() should be called to free the packet.

Parameter Description

IFace [IN] Zero-based index of available interfaces.

IPAddr [IN] IP address of the target host in network endianess.

fport [IN] Foreign port.

lport [IN] Local port.

pPacket [IN] Data which should be sent to the target host.

Table 7.11: IP_UDP_Send() parameter list

168 CHAPTER 7 UDP zero-copy interface

7.4.11 IP_UDP_SendAndFree()

Description

Send an UDP packet to a specified host and frees the packet.

Prototype

int IP_UDP_SendAndFree( int IFace,

IP_ADDR FHost,

U16 fport,

U16 lport,

IP_PACKET * pPacket );

Parameter

Return value

On success: 0

On error: Non-zero error code

Additional information

The packet pPacket has to be allocated by calling IP_UDP_Alloc(). Refer to

IP_UDP_Alloc() on page 72 for detailed information.

If you expect to get any response to this packet you should have opened a UDP con-

nection prior to calling this. Refer to IP_UDP_Open() on page 166 for more informa-

tion about creating an UDP connection.

Packets are freed by calling IP_UDP_SendAndFree(). Therefor, no call of

IP_UDP_Free() is required.

Parameter Description

IFace [IN] Zero-based index of available interfaces.

IPAddr [IN] IP address of the target host in network endianess.

fport [IN] Foreign port.

lport [IN] Local port.

pPacket [IN] Data which should be sent to the target host.

Table 7.12: IP_UDP_SendAndFree() parameter list

169

Chapter 8

DHCP client

This chapter explains the usage of the Dynamic Host Control Protocol (DHCP) with

embOS/IP. All API functions are described in this chapter.

170 CHAPTER 8 DHCP client

8.1 DHCP backgrounds

DHCP stands for Dynamic Host Configuration Protocol. It is designed to ease configu-

ration management of large networks by allowing the network administrator to col-

lect all the IP hosts “soft” configuration information into a single computer. This

includes IP address, name, gateway, and default servers. Refer to [RFC 2131] - DHCP

- Dynamic Host Configuration Protocol for detailed information about all settings

which can be assigned with DHCP.

DHCP is a “client/server” protocol, meaning that machine with the DHCP database

“serves” requests from DHCP clients. The clients typically initiate the transaction by

requesting an IP address and perhaps other information from the server. The server

looks up the client in its database, usually by the client’s media address, and assigns

the requested fields. Clients do not always need to be in the server’s database. If an

unknown client submits a request, the server may optionally assign the client a free

IP address from a “pool” of free addresses kept for this purpose. The server may also

assign the client default information of the local network, such as the default gate-

way, the DNS server, and routing information.

When the IP addresses is assigned, it is “leased” to the client for a finite amount of

time. The DHCP client needs to keep track of this lease time, and obtain a lease

extension from the server before the lease time runs out. Once the lease has

elapsed, the client should not send any more IP packets (except DHCP requests) until

he get another address. This approach allows computers (such as laptops or factory

floor monitors) which will not be permanently attached to the network to share IP

addresses and not hog them when they are not using the net.

DHCP is just a superset of the Bootstrap Protocol (BOOTP). The main differences

between the two are the lease concept, which was created for DHCP, and the ability

to assigned addresses from a pool. Refer to [RFC 951] - Bootstrap Protocol for

detailed information about the Bootstrap Protocol.

171

8.2 API functions

Function Description

IP_DHCPC_Activate() Activates the DHCP client.

IP_DHCPC_GetState() Returns the state of the DHCP client.

IP_DHCPC_Halt() Stops all DHCP client activity.

IP_DHCPC_SetCallback() Sets a callback for an interface.

Table 8.1: embOS/IP DHCP client interface function overview

172 CHAPTER 8 DHCP client

8.2.1 IP_DHCPC_Activate()

Description

Activates the DHCP client.

Prototype

void IP_DHCPC_Activate ( int IFIndex,

const char * sHost,

const char * sDomain,

const char * sVendor );

Parameter

Additional information

This function is typically called from within IP_X_Config(). This function initializes

the DHCP client. It attempts to open a UDP connection to listen for incoming replies

and begins the process of configuring a network interface using DHCP. The process

may take several seconds, and the DHCP client will keep retrying if the service does

not respond.

The parameters sHost, sDomain, sVendor are optional (can be NULL). If not NULL,

must point to a memory area which remains valid after the call since the string is not

copied.

Example

// Correct function call

IP_DHCPC_Activate(0, "Target", NULL, NULL);

// Illegal function call

char ac;

sprintf(ac, "Target%d, Index);

IP_DHCPC_Activate(0, ac, NULL, NULL);

// Correct function call

static char ac;

sprintf(ac, "Target%d, Index);

IP_DHCPC_Activate(0, ac, NULL, NULL);

If you start the DHCP client with activated logging the output on the terminal I/O

should be similar to the listing below:

DHCP: Sending discover!

DHCP: Received packet from 192.168.1.1

DHCP: Packet type is OFFER.

DHCP: Renewal time: 2160 min.

DHCP: Rebinding time: 3780 min.

DHCP: Lease time: 4320 min.

DHCP: Host name received.

DHCP: Sending Request.

DHCP: Received packet from 192.168.1.1

DHCP: Packet type is ACK.

DHCP: Renewal time: 2160 min.

DHCP: Rebinding time: 3780 min.

DHCP: Lease time: 4320 min.

DHCP: Host name received.

DHCP: IFace 0: IP: 192.168.199.20, Mask: 255.255.0.0, GW: 192.168.1.1.

Parameter Description

IFIndex [IN] Zero-based index number specifying the interface which should

request configuration information from a DHCP server.

sHost [IN] Pointer to host name to use in negotiation. Can be NULL.

sDomain [IN] Pointer to domain name to use in negotiation. Can be NULL.

sVendor [IN] Pointer to vendor to use in negotiation. Can be NULL.

Table 8.2: IP_DHCPC_Activate() parameter list

173

8.2.2 IP_DHCPC_GetState()

Description

Returns the state of the DHCP client.

Prototype

int IP_DHCPC_GetState( int IFIndex );

Parameter

Return value

0 DHCP client not used.

>0 DHCP client in use.

Parameter Description

IFIndex [IN] Zero-based index number specifying the interface for which the

state should be requested.

Table 8.3: IP_DHCPC_GetState() parameter list

174 CHAPTER 8 DHCP client

8.2.3 IP_DHCPC_Halt()

Description

Stops all DHCP activity on a network interface.

Prototype

void IP_DHCPC_Halt( int IFIndex );

Parameter

Parameter Description

IFIndex [IN] Zero-based index number specifying the interface which should

be halted.

Table 8.4: IP_DHCPC_Halt() parameter list

175

8.2.4 IP_DHCPC_SetCallback()

Description

This function allows the caller to set a callback for an interface.

Prototype

void IP_DHCPC_SetCallback( int IFIndex, int (*routine)(int,int) );

Parameter

Additional information

The callback is called with every status change. This mechanism is provided so that

the caller can do some processing when the interface is up (like doing initialization or

blinking LEDs, etc.). Refer to [RFC 2331] DHCP - Dynamic Host Configuration Proto-

col for detailed information about DHCP states.

Parameter Description

IFIndex [IN] Zero-based index number of available network interfaces.

(*routine) [IN] Callback functions which should be called with every status

change.

Table 8.5: IP_DHCPC_SetCallback() parameter list

176 CHAPTER 8 DHCP client

177

Chapter 9

AutoIP

All functions which are required to add AutoIP to your application are described in

this chapter.

178 CHAPTER 9 AutoIP

9.1 embOS/IP AutoIP backgrounds

The embOS/IP AutoIP module adds the dynamic configuration of IPv4 Link-Local

addresses to embOS/IP. This functionality is better known as AutoIP. Therefore, this

term will be used in this document.

The AutoIP implementation covers the relevant parts of the following RFCs:

In general AutoIP is a method to negotiate a IPv4 address in a network without the

utilization of a server such as a DHCP server. AutoIP will try to use IPv4 addresses

out of a reserved pool from the addresses 169.254.1.0 to 169.254.254.255 to find a

free IP that is not used by any other network participant at this time.

To achieve this goal AutoIP sends ARP probes into the network to ask if the addr. to

be used is already in use. This is determined by an ARP reply for the requested

address. Upon an address conflict AutoIP will generate a new address to use and will

retry to use it by sending ARP probes again.

RFC# Description

[RFC 3972] Dynamic Configuration of IPv4 Link-Local Addresses.

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc3972.txt

179

9.2 API functions

Function Description

IP_AutoIP_Activate() Activates AutoIP.

IP_AutoIP_Halt() Stops all AutoIP activity.

IP_AutoIP_SetUserCallback() Sets a callback to get a notification about

each status change.

IP_AutoIP_SetStartIP() Sets the IP address which will be used for

the first configuration try.

Table 9.1: embOS/IP AutoIP interface function overview

180 CHAPTER 9 AutoIP

9.2.1 IP_AutoIP_Activate()

Description

Activates AutoIP for the specified interface.

Prototype

void IP_AutoIP_Activate ( unsigned IFaceId );

Parameter

Additional information

Activating the dynamic configuration of IPv4 Link-Local addresses means that an

additional timer will be added to the stack. This timer will be called every second to

check the status of the address configuration. With the AutoIP activation an IP

address for the dynamic configuration will be created. The IPv4 prefix 169.254/16 is

registered with the IANA for this purpose. This means that embOS/IP will generate

an IP address similar to 169.254.xxx.xxx. The subnet mask of is always 255.255.0.0.

In embOS/IP debug builds terminal I/O output can be enabled. AutoIP outputs status

information in the terminal I/O window if the stack is configured to so

(IP_MTYPE_AUTOIP added to the log filter mask). Please refer to IP_SetLogFilter() on

page 439 and IP_AddLogFilter() on page 437 for further information about the

enabling terminal I/O. If terminal I/O is enabled the output of a the program start

should be similar to the following lines:

0:000 MainTask - INIT: Init started. Version 2.00.06

0:000 MainTask - DRIVER: Found PHY with Id 0x2000 at addr 0x1

0:000 MainTask - INIT: Link is down

0:000 MainTask - INIT: Init completed

0:000 IP_Task - INIT: IP_Task started

0:000 IP_RxTask - INIT: IP_RxTask started

3:000 IP_Task - LINK: Link state changed: Full duplex, 100 MHz

9:000 IP_Task - AutoIP: 169.254.240.240 checked, no conflicts

9:000 IP_Task - AutoIP: IFaceId 0: Using IP: 169.254.240.240.

Parameter Description

IFaceId [IN] Zero-based interface index.

Table 9.2: IP_AutoIP_Activate() parameter list

181

9.2.2 IP_AutoIP_Halt()

Description

Stops AutoIP activity for the passed interface.

Prototype

void IP_AutoIP_Halt ( unsigned IFaceId

U8 KeepIP );

Parameter

Return value

0 : Ok. AutoIP stopped. IP address cleared.

IP : Ok. AutoIP stopped. The IP address (for example, 0xA9FExxxx) has been kept.

-1 : Error. Illegal interface number.

Additional information

The function stops the AutoIP module. The IP address which was used during AutoIP

was activated, can be kept to speed up the configuration process after reactivating

AutoIP. If the IP address will not be kept, AutoIP creates a new IP address after the

reactivation.

Parameter Description

IFaceId [IN] Zero-based interface index.

KeepIP

[IN] Flag to indicate if the used IP address should be stored for the

next start of AutoIP. 0 means do not keep the IP, 1 means keep the

IP address for the next AutoIP start.

Table 9.3: IP_AutoIP_Halt() parameter list

182 CHAPTER 9 AutoIP

9.2.3 IP_AutoIP_SetUserCallback()

Description

Sets a callback function. It will be called with every status change.

Prototype

void IP_AutoIP_SetUserCallback( unsigned IFaceId,

IP_AUTOIP_INFORM_USER_FUNC * pfInformUser );

Parameter

Additional Information

The possibility to set a callback function is provided so that the caller can do some

processing when the interface is up (like doing initializations or blinking LEDs, etc.).

IP_AUTOIP_INFORM_USER_FUNC is defined as follows:

typedef void (IP_AUTOIP_INFORM_USER_FUNC)(U32 IFaceId, U32 Status);

Parameter Description

IFaceId [IN] Zero-based interface index.

pfInformUser [IN] Pointer to a user function of type IP_AUTOIP_INFORM_USER_FUNC

which is called when a status change occurs.

Table 9.4: IP_AutoIP_SetCallback() parameter list

183

9.2.4 IP_AutoIP_SetStartIP()

Description

Sets the IP address which will be used for the first configuration try.

Prototype

void IP_AutoIP_SetStartIP( unsigned IFaceId,

U32 IPAddr );

Parameter

Additional information

A call of this function is normally not required, but in some cases it can be useful to

set the IP address which should be used as starting point of the AutoIP functionality.

Parameter Description

IFaceId [IN] Zero-based interface index.

IPAddr [IN] 4-byte IPv4 address.

Table 9.5: IP_AutoIP_SetCallback() parameter list

184 CHAPTER 9 AutoIP

9.3 AutoIP resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the AutoIP module presented in the tables below

have been measured on an ARM7 and a Cortex-M3 system. Details about the further

configuration can be found in the sections of the specific example.

9.3.1 ROM usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

9.3.2 ROM usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

9.3.3 RAM usage

Addon ROM

embOS/IP AutoIP module approximately 1.1Kbyte

Table 9.6: AutoIP ROM usage ARM7

Addon ROM

embOS/IP AutoIP module approximately 1.0Kbyte

Table 9.7: AutoIP ROM usage Cortex-M3

Addon RAM

embOS/IP AutoIP module approximately 0.7Kbyte

Table 9.8: AutoIP RAM usage

185

Chapter 10

Address Collision Detection

All functions which are required to add Address Collision Detection (ACD) to your

application are described in this chapter.

186 CHAPTER 10 Address Collision Detection

10.1 embOS/IP ACD backgrounds

The embOS/IP ACD module allows the user specific configuration of the behavior if an

IPv4 address collision is detected. This means that more than one host in the net-

work is using the same IPv4 address at the same time. This is discovered sending

ARP discover packets to find hosts with the same addresses in the network.

187

10.2 API functions

Function Description

IP_ACD_Activate() Activates ACD.

IP_ACD_Config() Configures parameter for ACD.

Table 10.1: embOS/IP ACD interface function overview

188 CHAPTER 10 Address Collision Detection

10.2.1 IP_ACD_Activate()

Description

Activates ACD for the specified interface.

Prototype

int IP_ACD_Activate ( unsigned IFace );

Parameter

Return value

0 ACD activated and free IP found (does not mean the initial IP was good)

1 No IP address set when ACD was activated

Additional information

Activating the address conflict detection module means that a a hook into the ARP

module of the stack will be activated that allows the user to take action if an IPv4

address conflict on the network has been discovered.

When the ACD module is started it will check if the currently used IP address is in

conflict with any other host on the network by sending ARP probes to find hosts with

the same IPv4 address.

To allow the user to take action on those conflicts it is necessary to use

IP_ACD_Config() on page 189 before activating ACD.

In embOS/IP debug builds terminal I/O output can be enabled. ACD outputs status

information in the terminal I/O window if the stack is configured to so (IP_MTYPE_ACD

added to the log filter mask). Please refer to IP_SetLogFilter() on page 439 and

IP_AddLogFilter() on page 437 for further information about the enabling terminal I/

Parameter Description

IFace [IN] Zero-based interface index.

Table 10.2: IP_ACD_Activate() parameter list

189

10.2.2 IP_ACD_Config()

Description

Configures ACD behavior for startup and in case of conflicts.

Prototype

void IP_ACD_Config ( unsigned IFace

unsigned ProbeNum

unsigned DefendInterval

const ADC_FUNC * pACDContext );

Parameter

Parameter Description

IFace [IN] Zero-based interface index.

ProbeNum [IN] Number of ARP probes to send upon activating ACD before

declaring the actual used IP address to be free to be used.

DefendInterval [IN] Interval in which the currently active IP address is being

known as defended after taking action.

pACDContext [IN] Pointer to a structure of type ACD_FUNC.

Table 10.3: IP_ACD_Config() parameter list

190 CHAPTER 10 Address Collision Detection

10.3 ACD data structures

10.3.1 Structure ACD_FUNC

Description

Used to store function pointers to the user defined callbacks to take several actions

upon detecting an IP address conflict.

Prototype

typedef struct ACD_FUNC {

U32 (*pfRenewIPAddr);

int (*pfDefend);

int (*pfRestart);

} ACD_FUNC;

Member Description

pfRenewIPAddr

Function pointer to a user defined routine that is used to generate a

new IPv4 address if there is a collision detected during ACD activa-

tion.

pfDefend Function pointer to a user defined routine that is used to let the

user implement his own defend strategy. Can be NULL.

pfRestart Function pointer to a user defined routine that should reconfigure

the IP address used by the stack and optionally re-activates ACD.

Table 10.4: Structure ACD_FUNC member list

191

10.4 ACD resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the AutoIP module presented in the tables below

have been measured on an ARM7 and a Cortex-M3 system. Details about the further

configuration can be found in the sections of the specific example.

10.4.1 ROM usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

10.4.2 ROM usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

10.4.3 RAM usage

Addon ROM

embOS/IP ACD module approximately 0.4Kbyte

Table 10.5: ACD ROM usage ARM7

Addon ROM

embOS/IP ACD module approximately 0.4Kbyte

Table 10.6: ACD ROM usage Cortex-M3

Addon RAM

embOS/IP ACD module approximately 50Bytes

Table 10.7: ACD RAM usage

192 CHAPTER 10 Address Collision Detection

193

Chapter 11

UPnP (Add-on)

The embOS/IP implementation of UPnP which stand for Universal Plug and Play is an

optional extension to embOS/IP. It allows making your target easily discoverable and

advertising services available on your target throughout your network.

194 CHAPTER 11 UPnP (Add-on)

11.1 embOS/IP UPnP

The embOS/IP UPnP implementation is an optional extension which can be seam-

lessly integrated into your TCP/IP application. It combines the possibility to imple-

mented UPnP services in a most flexible way by allowing to specify content to be sent

upon UPnP requests completely generated by the application with a small memory

footprint.

The UPnP module implements the relevant parts of the UPnP documentation released

by the UPnP Forum.

The following table shows the contents of the embOS/IP root directory:

Document Download

UPnP Device Architecture 1.0 Direct download: http://upnp.org/specs/arch/UPnP-

arch-DeviceArchitecture-v1.0.pdf

Directory Content

Application

Contains the example application to run

the UPnP implementation with embOS/IP

and embOS/IP Web server add-on.

IP Contains the UPnP source file, IP_UPnP.c .

Supplied directory structure of embOS/IP UPnP package

195

11.2 Feature list

• Low memory footprint.

• Advertising your services on the network

•Easy to implement

196 CHAPTER 11 UPnP (Add-on)

11.3 Requirements

TCP/IP stack

The embOS/IP UPnP implementation requires the embOS/IP TCP/IP stack and is

designed to be used with the embOS/IP Web server add-on.

197

11.4 UPnP backgrounds

UPnP is designed to provide services throughout a network without interaction of the

user. It is designed to use standardised protocols such as IP, TCP, UDP, Multicast,

HTTP and XML for communication and to dirstribute services provided by a device.

UPnP can be used to advertise services provided by a device across the network such

as where to find the web interface for the device advertising. Newer operating sys-

tems support UPnP from scratch and will show UPnP devices available across a net-

work and may provide easy access to a device by simply selecting the discovered

UPnP device.

A typical usage would be to advertise media accessible on a media storage on the

network and opening a file browser window to the resource upon opening the UPnP

entry discovered.

11.4.1 Using UPnP to advertise your service in the network

The default UPnP XML file advertised is upnp.xml. A solution providing UPnP content

has to serve a file called upnp.xml containing valid UPnP descriptors via a web

server. The sample OS_IP_WebserverUPnP.c provides a sample configuration for

advertising a web server page that will open if the UPnP client clicks on the discov-

ered UPnP device.

A discovered UPnP device will typically be shown in the network neighborhood of your

operating system. A discovered device found by a Windows OS is shown in the pic-

ture below:

The example below shows the most important excerpts from the

OS_IP_WebserverUPnP.c sample that are necessary to setup a UPnP device in your

network.

Example

The sample provides some easy to use defines to adopt the identification strings used

by the UPnP device to advertise itself to be changed to your needs.

/* Excerpt from OS_IP_WebserverUPnP.c */

// UPnP

#define UPNP_FRIENDLY_NAME "SEGGER UPnP Demo"

#define UPNP_MANUFACTURER "SEGGER Microcontroller GmbH and Co. KG" // '&' is

not allowed

#define UPNP_MANUFACTURER_URL "http://www.segger.com"

#define UPNP_MODEL_DESC "SEGGER Web server with UPnP"

#define UPNP_MODEL_NAME "SEGGER UPnP Demo"

#define UPNP_MODEL_URL "http://www.segger.com/embos-ip-webserver.html"

The sample uses VFile hooks as described in IP_WEBS_AddVFileHook() on page 306

to provide dynamically serving the necessary XML files for UPnP without the need for

a real file system or further processing through the web server.

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* Types

**********************************************************************

typedef struct {

const char * sFileName;

const char * pData;

198 CHAPTER 11 UPnP (Add-on)

unsigned NumBytes;

} VFILE_LIST;

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* Static const

**********************************************************************

// UPnP, virtual files

static const char _acFile_dummy_xml[] =

"<?xml version=\"1.0\" encoding=\"utf-8\"?>\r\n"

"<scpd xmlns=\"urn:schemas-upnp-org:service-1-0\">\r\n"

"<specVersion>\r\n"

"<major>1</major>\r\n"

"<minor>0</minor>\r\n"

"</specVersion>\r\n"

"<serviceStateTable>\r\n"

"<stateVariable>\r\n"

"<name>Dummy</name>\r\n"

"<dataType>i1</dataType>\r\n"

"</stateVariable>\r\n"

"</serviceStateTable>\r\n"

"</scpd>";

// UPnP, virtual files list

static const VFILE_LIST _VFileList[] = {

"/dummy.xml", _acFile_dummy_xml, sizeof(_acFile_dummy_xml) - 1, // Do not count in

the null terminator of the string

NULL , NULL , NULL

};

/* Excerpt from OS_IP_WebserverUPnP.c */

// UPnP webserver VFile hook

static WEBS_VFILE_HOOK _UPnP_VFileHook;

Several helper functions are provided in the sample to easily generate a valid XML

file for advertising a service using UPnP.

/* Excerpt from OS_IP_WebserverUPnP.c */

// UPnP

#define UPNP_FRIENDLY_NAME "SEGGER UPnP Demo"

#define UPNP_MANUFACTURER "SEGGER Microcontroller GmbH and Co. KG" // '&' is

not allowed

#define UPNP_MANUFACTURER_URL "http://www.segger.com"

#define UPNP_MODEL_DESC "SEGGER Web server with UPnP"

#define UPNP_MODEL_NAME "SEGGER UPnP Demo"

#define UPNP_MODEL_URL "http://www.segger.com/embos-ip-webserver.html"

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* Static code

**********************************************************************

/*********************************************************************

199

* _UPnP_GetURLBase

* Function description

* This function copies the information needed for the URLBase parameter

* into the given buffer and returns a pointer to the start of the buffer

* for easy readable code.

* Parameters

* pBuffer - Pointer to the buffer that can be temporarily used to

* store the requested data.

* NumBytes - Size of the given buffer used for checks

* Return value

* Pointer to the start of the buffer used for storage.

static const char * _UPnP_GetURLBase(char * pBuffer, unsigned NumBytes) {

#define URL_BASE_PREFIX "http://"

char * p;

p = pBuffer;

*p = '\0'; // Just to be on the safe if the buffer is too small

strncpy(pBuffer, URL_BASE_PREFIX, NumBytes);

p += (sizeof(URL_BASE_PREFIX) - 1);

NumBytes -= (sizeof(URL_BASE_PREFIX) - 1);

IP_PrintIPAddr(p, IP_GetIPAddr(INTERFACE), NumBytes);

return pBuffer;

}

/*********************************************************************

* _UPnP_GetModelNumber

* Function description

* This function copies the information needed for the ModelNumber parameter

* into the given buffer and returns a pointer to the start of the buffer

* for easy readable code.

* Parameters

* pBuffer - Pointer to the buffer that can be temporarily used to

* store the requested data.

* NumBytes - Size of the given buffer used for checks

* Return value

* Pointer to the start of the buffer used for storage.

static const char * _UPnP_GetModelNumber(char * pBuffer, unsigned NumBytes) {

U8 aHWAddr[6];

if (NumBytes <= 12) {

*pBuffer = '\0'; // Just to be on the safe if the buffer is too small

} else {

IP_GetHWAddr(INTERFACE, aHWAddr, sizeof(aHWAddr));

snprintf(pBuffer, NumBytes, "%02X%02X%02X%02X%02X%02X", aHWAddr[0], aHWAddr[1],

aHWAddr[2], aHWAddr[3], aHWAddr[4], aHWAddr[5]);

}

return pBuffer;

}

/*********************************************************************

* _UPnP_GetSN

* Function description

* This function copies the information needed for the SerialNumber parameter

* into the given buffer and returns a pointer to the start of the buffer

200 CHAPTER 11 UPnP (Add-on)

* for easy readable code.

* Parameters

* pBuffer - Pointer to the buffer that can be temporarily used to

* store the requested data.

* NumBytes - Size of the given buffer used for checks

* Return value

* Pointer to the start of the buffer used for storage.

static const char * _UPnP_GetSN(char * pBuffer, unsigned NumBytes) {

U8 aHWAddr[6];

if (NumBytes <= 12) {

*pBuffer = '\0'; // Just to be on the safe if the buffer is too small

} else {

IP_GetHWAddr(INTERFACE, aHWAddr, sizeof(aHWAddr));

snprintf(pBuffer, NumBytes, "%02X%02X%02X%02X%02X%02X", aHWAddr[0], aHWAddr[1],

aHWAddr[2], aHWAddr[3], aHWAddr[4], aHWAddr[5]);

}

return pBuffer;

}

/*********************************************************************

* _UPnP_GetUDN

* Function description

* This function copies the information needed for the UDN parameter

* into the given buffer and returns a pointer to the start of the buffer

* for easy readable code.

* Parameters

* pBuffer - Pointer to the buffer that can be temporarily used to

* store the requested data.

* NumBytes - Size of the given buffer used for checks

* Return value

* Pointer to the start of the buffer used for storage.

static const char * _UPnP_GetUDN(char * pBuffer, unsigned NumBytes) {

#define UDN_PREFIX "uuid:56F9C1D5-5083-4ee5-A6B3-"

char * p;

U8 aHWAddr[6];

p = pBuffer;

*pBuffer = '\0'; // Just to be on the safe if the buffer is too small

strncpy(pBuffer, UDN_PREFIX, NumBytes);

p += (sizeof(UDN_PREFIX) - 1);

NumBytes -= (sizeof(UDN_PREFIX) - 1);

if (NumBytes > 12) {

IP_GetHWAddr(INTERFACE, aHWAddr, sizeof(aHWAddr));

snprintf(p, NumBytes, "%02X%02X%02X%02X%02X%02X", aHWAddr[0], aHWAddr[1],

aHWAddr[2], aHWAddr[3], aHWAddr[4], aHWAddr[5]);

}

return pBuffer;

}

/*********************************************************************

* _UPnP_GetPresentationURL

* Function description

* This function copies the information needed for the presentation URL parameter

* into the given buffer and returns a pointer to the start of the buffer

* for easy readable code.

201

* Parameters

* pBuffer - Pointer to the buffer that can be temporarily used to

* store the requested data.

* NumBytes - Size of the given buffer used for checks

* Return value

* Pointer to the start of the buffer used for storage.

static const char * _UPnP_GetPresentationURL(char * pBuffer, unsigned NumBytes) {

#define PRESENTATION_URL_PREFIX "http://"

#define PRESENTATION_URL_POSTFIX "/index.htm"

char * p;

int i;

p = pBuffer;

*p = '\0'; // Just to be on the safe if the buffer is too small

strncpy(pBuffer, PRESENTATION_URL_PREFIX, NumBytes);

p += (sizeof(PRESENTATION_URL_PREFIX) - 1);

NumBytes -= (sizeof(PRESENTATION_URL_PREFIX) - 1);

i = IP_PrintIPAddr(p, IP_GetIPAddr(INTERFACE), NumBytes);

p += i;

NumBytes -= i;

strncat(pBuffer, PRESENTATION_URL_POSTFIX, NumBytes);

return pBuffer;

}

/*********************************************************************

* _UPnP_GenerateSend_upnp_xml

* Function description

* Send the content for the requested file using the callback provided.

* Parameters

* pContextIn - Send context of the connection processed for

* forwarding it to the callback used for output.

* pf - Function pointer to the callback that has to be

* for sending the content of the VFile.

* pContextOut - Out context of the connection processed.

* pData - Pointer to the data that will be sent

* NumBytes - Number of bytes to send from pData. If NumBytes

* is passed as 0 the send function will run a strlen()

* on pData expecting a string.

* Notes

* (1) The data does not need to be sent in one call of the callback

* routine. The data can be sent in blocks of data and will be

* flushed out automatically at least once returning from this

* routine.

static void _UPnP_GenerateSend_upnp_xml(void * pContextIn, void (*pf) (void * pCon-

textOut, const char * pData, unsigned NumBytes)) {

char ac[128];

pf(pContextIn, "<?xml version=\"1.0\"?>\r\n"

"<root xmlns=\"urn:schemas-upnp-org:device-1-0\">\r\n"

"<specVersion>\r\n"

"<major>1</major>\r\n"

"<minor>0</minor>\r\n"

"</specVer-

sion>\r\n" , 0);

pf(pContextIn, "<URL-

Base>" , 0);

pf(pContextIn, _UPnP_GetURLBase(ac, sizeof(ac))

202 CHAPTER 11 UPnP (Add-on)

, 0);

pf(pContextIn, "</URL-

Base>\r\n" , 0);

pf(pContextIn, "<device>\r\n"

"<deviceType>urn:schemas-upnp-org:device:Basic:1</device-

Type>\r\n" , 0);

pf(pContextIn, "<friendlyName>" UPNP_FRIENDLY_NAME "</friend-

lyName>\r\n" , 0);

pf(pContextIn, "<manufacturer>" UPNP_MANUFACTURER "</manufac-

turer>\r\n" , 0);

pf(pContextIn, "<manufacturerURL>" UPNP_MANUFACTURER_URL "</manufacture-

rURL>\r\n" , 0);

pf(pContextIn, "<modelDescription>" UPNP_MODEL_DESC "</modelDescrip-

tion>\r\n" , 0);

pf(pContextIn, "<modelName>" UPNP_MODEL_NAME "</model-

Name>\r\n" , 0);

pf(pContextIn, "<modelNum-

ber>" , 0);

pf(pContextIn, _UPnP_GetModelNumber(ac, sizeof(ac))

, 0);

pf(pContextIn, "</modelNum-

ber>\r\n" , 0);

pf(pContextIn, "<modelURL>" UPNP_MODEL_URL "</mode-

lURL>\r\n" , 0);

pf(pContextIn, "<serialNum-

ber>" , 0);

pf(pContextIn, _UPnP_GetSN(ac, sizeof(ac))

, 0);

pf(pContextIn, "</serialNum-

ber>\r\n" , 0);

pf(pContextIn, "<UDN>"

, 0);

pf(pContextIn, _UPnP_GetUDN(ac, sizeof(ac))

, 0);

pf(pContextIn, "</UDN>\r\n"

, 0);

pf(pContextIn, "<serviceList>\r\n"

"<service>\r\n"

"<serviceType>urn:schemas-upnp-org:service:Dummy:1</service-

Type>\r\n"

"<serviceId>urn:upnp-org:serviceId:Dummy</serviceId>\r\n"

"<SCPDURL>/dummy.xml</SCPDURL>\r\n"

"<controlURL>/</controlURL>\r\n"

"<eventSubURL></eventSubURL>\r\n"

"</service>\r\n"

"</service-

List>\r\n" , 0);

pf(pContextIn, "<presentation-

URL>" , 0);

pf(pContextIn, _UPnP_GetPresentationURL(ac, sizeof(ac))

, 0);

pf(pContextIn, "</presentation-

URL>\r\n" , 0);

pf(pContextIn, "</device>\r\n"

"</root>"

, 0);

}

203

The callbacks for providing a virtual file using a VFile hook allow providing dynami-

cally created content for every file requested from the web server as soon as possi-

ble. A file served from a VFile hook will not be processed further by the web server

code.

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* Static code

**********************************************************************

/*********************************************************************

* _UPnP_CheckVFile

* Function description

* Check if we have content that we can deliver for the requested

* file using the VFile hook system.

* Parameters

* sFileName - Name of the file that is requested

* pIndex - Pointer to a variable that has to be filled with

* the index of the entry found in case of using a

* filename<=>content list.

* Alternative all comparisons can be done using the

* filename. In this case the index is meaningless

* and does not need to be returned by this routine.

* Return value

* 0 - We do not have content to send for this filename,

* fall back to the typical methods for retrieving

* a file from the web server.

* 1 - We have content that can be sent using the VFile

* hook system.

static int _UPnP_CheckVFile(const char * sFileName, unsigned * pIndex) {

unsigned i;

// Generated VFiles

if (strcmp(sFileName, "/upnp.xml") == 0) {

return 1;

}

// Static VFiles

for (i = 0; i < SEGGER_COUNTOF(_VFileList); i++) {

if (strcmp(sFileName, _VFileList[i].sFileName) == 0) {

*pIndex = i;

return 1;

}

return 0;

}

/*********************************************************************

* _UPnP_SendVFile

* Function description

* Send the content for the requested file using the callback provided.

* Parameters

* pContextIn - Send context of the connection processed for

204 CHAPTER 11 UPnP (Add-on)

* forwarding it to the callback used for output.

* Index - Index of the entry of a filename<=>content list

* if used. Alternative all comparisons can be done

* using the filename. In this case the index is

* meaningless. If using a filename<=>content list

* this is faster than searching again.

* sFileName - Name of the file that is requested. In case of

* working with the Index this is meaningless.

* pf - Function pointer to the callback that has to be

* for sending the content of the VFile.

* pContextOut - Out context of the connection processed.

* pData - Pointer to the data that will be sent

* NumBytes - Number of bytes to send from pData. If NumBytes

* is passed as 0 the send function will run a strlen()

* on pData expecting a string.

static void _UPnP_SendVFile(void * pContextIn, unsigned Index, const char * sFile-

Name, void (*pf) (void * pContextOut, const char * pData, unsigned NumBytes)) {

(void)sFileName;

// Generated VFiles

if (strcmp(sFileName, "/upnp.xml") == 0) {

_UPnP_GenerateSend_upnp_xml(pContextIn, pf);

return;

}

// Static VFiles

pf(pContextIn, _VFileList[Index].pData, _VFileList[Index].NumBytes);

}

static WEBS_VFILE_APPLICATION _UPnP_VFileAPI = {

_UPnP_CheckVFile,

_UPnP_SendVFile

};

All that is needed to be added to your application in order to provide the necessary

XML files through embOS/IP Web server and starting UPnP advertising are the follow-

ing lines:

/* Excerpt from OS_IP_WebserverUPnP.c */

// Activate UPnP with VFile hook for needed XML files

IP_WEBS_AddVFileHook(&_UPnP_VFileHook, &_UPnP_VFileAPI);

IP_UPNP_Activate(INTERFACE, NULL);

205

11.5 API functions

Function Description

IP_UPNP_Activate() Activates UPnP advertisement of the target

in the network.

Table 11.1: embOS/IP UPnP API function overview

206 CHAPTER 11 UPnP (Add-on)

11.5.1 IP_UPNP_Activate()

Description

Activates the UPnP server.

Prototype

void IP_UPNP_Activate( unsigned IFace,

const char * acUDN );

Parameter

Additional infromation

If acUDN is NULL the unique descriptor name will be generated from the HW addr. of

the interface.

Parameter Description

IFace [IN] Zero-based index of available network interfaces.

acUDN [IN] String containing a unique descriptor name. (Optional, can be

NULL.)

Table 11.2: IP_UPNP_Activate() parameter list

207

11.6 UPnP resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the UPnP modules presented in the tables below

have been measured on an ARM7 and a Cortex-M3 system. Details about the further

configuration can be found in the sections of the specific example.

The pure size of the UPnP add-on has been measured as the size of the services pro-

vided may vary.

11.6.1 ROM usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

11.6.2 ROM usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

11.6.3 RAM usage

Addon ROM

embOS/IP UPnP approximately 2.2Kbyte

Table 11.3: UPnP ROM usage ARM7

Addon ROM

embOS/IP UPnP approximately 2.0Kbyte

Table 11.4: UPnP ROM usage Cortex-M3

Addon RAM

embOS/IP UPnP approximately 170 bytes

Table 11.5: UPnP RAM usage

208 CHAPTER 11 UPnP (Add-on)

209

Chapter 12

VLAN

The embOS/IP implementation of VLAN which stand for Virtual LAN allows seperating

your network into multiple networks without the need to seperate it physically. This

chapter will show you how easily VLAN access can be setup on your target.

210 CHAPTER 12 VLAN

12.1 embOS/IP VLAN

The embOS/IP VLAN implementation allows a fast and easy implement of VLAN on

your target. embOS/IP VLAN support supports a basic VLAN tag specifying only a

VLAN ID.

211

12.2 Feature list

• Low memory footprint.

• Easy to implement.

• Software based solution without the need for a driver to support VLAN tags.

212 CHAPTER 12 VLAN

12.3 VLAN backgrounds

VLAN technology can be used to seperate multiple devices operating on the same

physical network into completely seperated networks without seeing each other.

A typical usage would be to have 2 departments seperated from each other but using

the same infrastructure such as a shared switch or router. Only devices using the

same VLAN ID will be able to see each other.

For this to happen 4 bytes are added in front of the packet type field in the Ethernet

frame pushing the original packet type field back by 4 bytes. The Ethernet frame will

still be of a maximum length 1518 bytes including CRC what means that instead of a

maximum of 1500 bytes that can be transferred the amount of bytes that can be

transferred per Ethernet frame will shrink to 1496 bytes per packet. VLAN tagged

packets are typically forwarded by any switch as they are as the type field has been

simply replaced and in most cases only the destination MAC, source MAC and packet

type is checked. In this case the packet is simply of an unknown protocol and will be

forwarded by the switch.

The picture below shows the structure of an Ethernet frame once without using a

VLAN tag and once with using a VLAN tag being assigned to VLAN ID #2.

Dest

MAC

00:23:C7:FF:FF:FF 00:23:C7:FF:EE:EE

Src

MAC

VLAN

TAG

TPI 16 bit TCI

(12 bit VLAN ID)

0x8100

VLAN ID #2

0x0002

Packet

Type

IP Packet

0x0800

Packet

Data

Dest

MAC

00:23:C7:FF:FF:FF 00:23:C7:FF:EE:EE

Src

MAC

Packet

Type

IP Packet

0x0800

Packet

Data

Ethernet frame of max. 1518 bytes

Max. 1500 bytes data + 4 bytes CRC

Max. 1496 bytes data + 4 bytes

CRC

Ethernet frame of max. 1518 bytes

213

12.4 API functions

Function Description

IP_VLAN_AddInterface() Activates UPnP advertisement of the target

in the network.

Table 12.1: embOS/IP VLAN API function overview

214 CHAPTER 12 VLAN

12.4.1 IP_VLAN_AddInterface()

Description

Adds a VLAN interface.

Prototype

int IP_VLAN_AddInterface( unsigned HWIFace,

U16 VLANId );

Parameter

Return value

Zero-based index of the added VALN interface.

Parameter Description

HWIFace [IN] Zero-based index of available network interfaces to be used as

physical interface for the VLAN pseudo interface.

VLANId [IN] 12 bit VLAN ID.

Table 12.2: IP_VLAN_AddInterface() parameter list

215

12.5 VLAN resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the VLAN modules presented in the tables below

have been measured on an ARM7 and a Cortex-M3 system. Details about the further

configuration can be found in the sections of the specific example.

12.5.1 ROM usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

12.5.2 ROM usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

12.5.3 RAM usage

Addon ROM

embOS/IP VLAN approximately 1.2Kbyte

Table 12.3: VLAN ROM usage ARM7

Addon ROM

embOS/IP VLAN approximately 1.0Kbyte

Table 12.4: VLAN ROM usage Cortex-M3

Addon RAM

embOS/IP VLAN approximately 16 bytes

Table 12.5: VLAN RAM usage

216 CHAPTER 12 VLAN

217

Chapter 13

Network interface drivers

embOS/IP has been designed to cooperate with any kind of hardware. To use specific

hardware with embOS/IP, a so-called network interface driver for that hardware is

required. The network interface driver consists of basic functions for accessing the

hardware and a global table that holds pointers to these functions.

218 CHAPTER 13 Network interface drivers

13.1 General information

To use embOS/IP, a network interface driver matching the target hardware is

required. The code size of a network interface driver depends on the hardware and is

typically between 1 and 3 Kbytes. The driver handles both the MAC (media access

control) unit as well as the PHY (Physical interface). We recommend using drivers

written and tested by SEGGER. However, it is possible to write your own driver. This

is explained in section Writing your own driver on page 248.

The driver interface has been designed to allow support of internal and external

Ethernet controllers (EMACs). It also allows to take full advantage of hardware fea-

tures such as MAC address filtering and checksum computation in hardware.

13.1.1 MAC address filtering

The stack passes a list of MAC addresses to the driver. The driver is responsible for

making sure that all packets from all MAC addresses specified are passed to the

stack. It can do so with “precise filtering” if the hardware has sufficient filters for the

given number of MAC addresses. If more MAC addresses are passed to the driver

than hardware filters are available, the driver can use a hash filter if available in

hardware or switch to promiscuous mode.

This is a very flexible solution which allows making best use of the hardware filtering

capabilities on all known Ethernet controllers. It also allows simple implementations

to simply switch to promiscuous mode.

13.1.2 Checksum computation in hardware

When the interface is initialized, the stack queries the capabilities of the driver. If the

hardware can compute IP, TCP, UDP, ICMP checksums, it can indicates this to the

stack. In this case, the stack does not compute these checksums, improving through-

put and reducing CPU load.

13.1.3 Ethernet CRC computation

Every Ethernet packet includes a 32-bit trailing CRC. In most cases, the Ethernet

controller is capable of computing the CRC. The drivers take advantage of this. The

CRC is computed in the driver only if the hardware does not support CRC computa-

tion.

219

13.2 Available network interface drivers

Network interface drivers are optional components to embOS/IP. The following net-

work interface drivers are available:

To add a driver to embOS/IP, IP_AddEtherInterface() should be called with the

proper identifier before the TCP/IP stack starts any transmission. Refer to

IP_AddEtherInterface() on page 46 for detailed information.

Driver (Device) Identifier

ATMEL AT91CAP9 IP_Driver_CAP9

ATMEL AT91RM9200 IP_Driver_AT91RM9200

ATMEL AT91SAM7X IP_Driver_SAM7X

ATMEL AT91SAM9260 IP_Driver_SAM9260

ATMEL AT91SAM9263 IP_Driver_SAM9263

ATMEL AT91SAMG20 IP_Driver_SAM9G20

ATMEL AT91SAMG45 IP_Driver_SAMG45

ATMEL AT91SAM9XE IP_Driver_SAM9XE

ATMEL AVR32UC IP_Driver_AVR32UC

DAVICOM DM9000 IP_Driver_DM9000

FREESCALE ColdFire MCF5223x IP_Driver_MCF5223x

FREESCALE ColdFire MCF5329 IP_Driver_MCF5329

NIOSII IFI GMACII EMAC IP_Driver_GMACII

NIOSII MaCo-Engineering EMAC IP_Driver_NIOSII_MaCo

NIOSII More than IP A2A bridge IP_Driver_NIOSII_More10IP_A2A

NXP LPC17xx IP_Driver_LPC17xx

NXP LPC2378 / LPC2478 IP_Driver_LPC24xx

NXP LPC32xx IP_Driver_LPC32xx

RENESAS H8S2472 IP_Driver_H8S2472

RENESAS RX62N IP_Driver_RX62N

RENESAS SH7670 IP_Driver_SH7670

RENESAS (NEC) V850JGH3 IP_Driver_V850JGH3

SMSC LAN9115 / LAN9215 IP_Driver_LAN9115

SMSC LAN9118 IP_Driver_LAN9118

SMSC LAN91C111 IP_Driver_LAN91C111

ST STM32F107 (Connectivity Line) IP_Driver_STM32F107

ST STM32F207 IP_Driver_STM32F207

ST STR912 IP_Driver_STR912

TI (LUMINARY) LM3S6965 IP_Driver_LM3S6965

TI (LUMINARY) LM3S9B90 IP_Driver_LM3S9B90

Table 13.1: List of default network interface driver labels

220 CHAPTER 13 Network interface drivers

13.2.1 ATMEL AT91CAP9

Atmel's CAP™ is a microcontroller-based system-on-chip platform with a Metal Pro-

grammable (MP) Block that allows the designer to add custom logic.

13.2.1.1 Supported hardware

The network interface driver for the AT91CAP9 can be used with every ATMEL

AT91CAP9 target board. The driver has been tested on the following eval boards:

13.2.1.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_CAP9. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

void IP_X_Config(void) {

int mtu;

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_CAP9); // Add Ethernet driver

IP_SetHWAddr("\x00\x22\xC7\xFF\xFF\xFF"); // MAC addr: Needs to be unique

// for production units

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Set supported duplex modes

// 10Mbit half duplex, 10Mbit full duplex, 100Mbit half duplex

// and 100Mbit full duplex are supported.

IP_SetSupportedDuplexModes(0, IP_PHY_MODE_10_HALF

| IP_PHY_MODE_10_FULL

| IP_PHY_MODE_100_HALF

| IP_PHY_MODE_100_FULL );

IP_NI_ConfigPHYMode (0, 1); // Use RMII mode

// Run-time configure buffers.

// The default setup will do for most cases.

mtu = 1500; // 576 is minimum acc. to RFC,

// 1500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is

// 1500 for ethernet by default

IP_AddBuffers(12, 256); // Small buffers.

IP_AddBuffers(8, mtu + 40 + 16); // Big buffers. Size should be

// mtu + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(8 * (mtu-40), 8 * (mtu-40));

// Use DHCP client or define IP address, subnet mask,

// gateway address and DNS server according to the

// requirements of your application.

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Do not filter:

// Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP);

}

Tested evaluation boards

ATMEL CAP-DK

Table 13.2: List of tested eval boards

221

222 CHAPTER 13 Network interface drivers

13.2.1.3 Driver specific configuration functions

13.2.1.3.1 IP_NI_CAP9_ConfigNumRxBuffers

Description

Sets the number of Rx buffers of the driver. This function has to be called in the con-

figuration phase.

Prototype

void IP_NI_CAP9_ConfigNumRxBuffers( U16 NumRxBuffers );

Parameter

Function Description

IP_NI_CAP9_ConfigNumRxBuffers() Sets the number of Rx buffers.

Table 13.3: embOS/IP CAP9 driver specific function overview

Parameter Description

NumRxBuffers [IN] The number of Rx buffers.

Table 13.4: IP_NI_CAP9_ConfigNumRxBuffers() parameter list

223

13.2.1.4 Required BSP functions

13.2.1.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

Parameter

Example

/* Excerpt of BSP.c for the ATMEL AT91CAP9 CAP-DK */

/*********************************************************************

* BSP_ETH_Init()

* Function description

* This function is called from the network interface driver.

* It initializes the network interface. This function should be used

* to enable the ports which are connected to the network hardware.

* It is called from the driver during the initialization process.

void BSP_ETH_Init(unsigned Unit) {

unsigned PinsA;

unsigned v;

_PMC_PCER = (1 << _ID_EMAC_PORT); // Enable clock for PIO

_EMAC_PORT_PPUDR = (1 << _EMAC_PORT_RXDV_BIT); // Disable RXDV pullup,

// enter PHY normal mode

// Init PIO and perform a RESET of PHY since PHY

v = 0

| (1 << _EMAC_PORT_RXDV_BIT)

;

_PIOB_PER = v;

_PIOB_OER = v;

_PIOB_CODR = 0

| (1 << _EMAC_PORT_RXDV_BIT)

;

_PIOB_SODR = 0

| (1 << 0) // Isolate

;

// Perform hardware reset using RESET pin of MCU

AT91C_RSTC_RMR = 0xA5000000 | AT91C_RSTC_ERSTL & (1 << 8);

AT91C_RSTC_RCR = 0xA5000000 | AT91C_RSTC_EXTRST;

while ((AT91C_RSTC_RSR & AT91C_RSTC_NRSTL) == 0); // Wait until RESET timer has

// expired (just a few ms)

// Init PIO Pins: EMAC is connected to specific lines of PIO

PinsA = (1uL << 11) // ETH_MDINTR

| (1uL << 21) // ETXCK

| (1uL << 22) // ERXDV

| (1uL << 23) // ETX0

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.5: embOS/IP driver specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.6: BSP_ETH_Init() parameter list

224 CHAPTER 13 Network interface drivers

| (1uL << 24) // ETX1

| (1uL << 25) // ERX0

| (1uL << 26) // ERX1

| (1uL << 27) // ERXER

| (1uL << 28) // ETXEN

| (1uL << 29) // EMDC

| (1uL << 30) // EMDIO

;

_EMAC_PORT_ASR = PinsA; // Select peripheral A use

_EMAC_PORT_PDR = PinsA; // Disable GPIO mode,

// select peripheral function

}

13.2.1.5 Additional information

None.

225

13.2.2 ATMEL AT91RM9200

The ATMEL AT919200 is based on the ARM920T processor. Its peripheral set includes

USB Full Speed Host and Device Ports, 10/100 Base T Ethernet MAC, Multimedia Card

Interface (MCI), three Synchronous Serial Controllers (SSC), four USARTs, Master/

Slave Serial Peripheral Interface (SPI), Timer Counters (TC) and Two Wire Interface

(TWI), four 32-bit Parallel I/O Controllers and peripheral DMA channels.

13.2.2.1 Supported hardware

The network interface driver for the AT91RM9200 can be used with every ATMEL

AT91RM9200 target board. The driver has been tested on the following eval board(s):

13.2.2.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_RM9200. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

void IP_X_Config(void) {

int mtu;

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_AT91RM9200); // Add Ethernet driver

IP_SetHWAddr("\x00\x22\xC7\xFF\xFF\xFF"); // MAC addr: Needs to be unique

// for production units

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Set supported duplex modes

// 10Mbit half duplex, 10Mbit full duplex, 100Mbit half duplex

// and 100Mbit full duplex are supported.

IP_SetSupportedDuplexModes(0, IP_PHY_MODE_10_HALF

| IP_PHY_MODE_10_FULL

| IP_PHY_MODE_100_HALF

| IP_PHY_MODE_100_FULL );

IP_NI_ConfigPHYMode (0, 1); // Use RMII mode

// Run-time configure buffers.

// The default setup will do for most cases.

mtu = 1500; // 576 is minimum acc. to RFC,

// 1500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is

// 1500 for ethernet by default

IP_AddBuffers(12, 256); // Small buffers.

IP_AddBuffers(8, mtu + 40 + 16); // Big buffers. Size should be

// mtu + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(8 * (mtu-40), 8 * (mtu-40));

// Use DHCP client or define IP address, subnet mask,

// gateway address and DNS server according to the

// requirements of your application.

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Do not filter:

// Output all warnings.

Tested evaluation boards

ATMEL AT91RM9200-EK

Table 13.7: List of tested eval boards

226 CHAPTER 13 Network interface drivers

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP);

}

13.2.2.3 Driver specific configuration functions

13.2.2.3.1 IP_NI_AT91RM9200_ConfigNumRxBuffers

Description

Sets the number of Rx buffers of the driver. This function has to be called in the con-

figuration phase.

Prototype

void IP_NI_AT91RM9200_ConfigNumRxBuffers( U16 NumRxBuffers );

Parameter

Function Description

IP_NI_AT91RM9200_ConfigNumRxBuffers() Sets the number of Rx buffers.

Table 13.8: embOS/IP RM9200 driver specific function overview

Parameter Description

NumRxBuffers [IN] The number of Rx buffers.

Table 13.9: IP_NI_RM9200_ConfigNumRxBuffers() parameter list

227

13.2.2.4 Required BSP functions

13.2.2.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

Parameter

Example

/* Excerpt of BSP.c for the ATMEL AT91RM9200-EK */

#define _PIOA_BASE_ADDR (0xFFFFF400UL)

#define _PMC_BASE_ADDR (0xFFFFFC00UL)

#define _PIO_PUDR_OFF (0x60)

#define _PIO_PUER_OFF (0x64)

#define _PIO_ASR_OFF (0x70)

#define _PIO_BSR_OFF (0x74)

#define _PMC (*(volatile unsigned int*)(_PMC_BASE_ADDR))

#define _PMC_PCER (*(volatile unsigned int*)(_PMC_BASE_ADDR + 0x10))

#define _PMC_PCDR (*(volatile unsigned int*)(_PMC_BASE_ADDR + 0x14))

#define _PIOA_ASR (*(volatile unsigned int*)(_PIOA_BASE_ADDR + _PIO_ASR_OFF))

#define _PIOA_BSR (*(volatile unsigned int*)(_PIOA_BASE_ADDR + _PIO_BSR_OFF))

#define _PIOA_PUDR (*(volatile unsigned int*)(_PIOA_BASE_ADDR + _PIO_PUDR_OFF))

#define _PIOA_PUER (*(volatile unsigned int*)(_PIOA_BASE_ADDR + _PIO_PUER_OFF))

#define _PIOA_ID (2) // Parallel IO Controller A

#define _PIOB_ID (3) // Parallel IO Controller B

#define _EMAC_ID (24) // EMAC

/*********************************************************************

* BSP_ETH_Init()

void BSP_ETH_Init(unsigned Unit) {

unsigned int Pins;

// Initialize peripheral clock

_PMC_PCER = (1 << _EMAC_ID); // Ensure the clock for EMAC is enabled

_PMC_PCER = (1 << _PIOA_ID); // Ensure the clock for PIOA is enabled

_PIOA_PUDR = (1 << 11); // Disable RXDV pullup, enter PHY normal mode

// Note: the PHY has an internal pull-down

_PIOA_PUER = (1 << 16); // Enable Pull-Up on EMDIO pin

#ifdef RMII

Pins = ((unsigned int) (1 << 7))

| ((unsigned int) (1 << 8))

| ((unsigned int) (1 << 9))

| ((unsigned int) (1 << 10))

| ((unsigned int) (1 << 11))

| ((unsigned int) (1 << 12))

| ((unsigned int) (1 << 13))

| ((unsigned int) (1 << 14))

| ((unsigned int) (1 << 15))

| ((unsigned int) (1 << 16))

;

#else

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.10: embOS/IP driver specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.11: BSP_ETH_Init() parameter list

228 CHAPTER 13 Network interface drivers

#error "MII-mode not supported by AT91RM9200-EK"

#endif

_PIOA_ASR = Pins; // Select peripheral A use of the associated pins

_PIOA_BSR = 0; // Select peripheral B, no peripheral B pins used

_PIOA_PDR = Pins; // Set peripheral control of the associated pins

}

13.2.2.5 Additional information

None.

229

13.2.3 ATMEL AT91SAM7X

The ATMEL AT91SAM7X’s are flash microcontrollers with integrated Ethernet, USB

and CAN interfaces, based on the 32-bit ARM7TDMI RISC processor.

13.2.3.1 Supported hardware

The network interface driver for the AT91SAM7X can be used with every ATMEL

AT91SAM7X target board. The driver has been tested on the following eval boards:

13.2.3.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_SAM7X. This function has to be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_SAM7X); // Add Ethernet driver

IP_SetHWAddr("\x00\x22\xC7\xFF\xFF\xFF"); // MAC addr: Needs to be unique

// for production units

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Set supported duplex modes

// 10Mbit half duplex, 10Mbit full duplex, 100Mbit half duplex

// and 100Mbit full duplex are supported.

IP_SetSupportedDuplexModes(0, IP_PHY_MODE_10_HALF

| IP_PHY_MODE_10_FULL

| IP_PHY_MODE_100_HALF

| IP_PHY_MODE_100_FULL

);

// Run-time configure buffers.

// The default setup will do for most cases.

mtu = 1500; // 576 is minimum acc. to RFC,

// 1500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is

// 1500 for ethernet by default

IP_AddBuffers(12, 256); // Small buffers.

IP_AddBuffers(6, mtu + 40 + 16); // Big buffers. Size should be

// mtu + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(3 * (mtu-40), 3 * (mtu-40));

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Do not filter:

// Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP);

}

Tested evaluation boards

ATMEL AT91SAM7X-EK

Olimex SAM7-EX256

Table 13.12: List of tested eval boards

230 CHAPTER 13 Network interface drivers

13.2.3.3 Driver specific configuration functions

13.2.3.3.1 IP_NI_SAM7X_ConfigNumRxBuffers()

Description

Sets the number of Rx buffers of the driver. This function has to be called in the con-

figuration phase.

Prototype

void IP_NI_SAM7X_ConfigNumRxBuffers( U16 NumRxBuffers );

Parameter

Function Description

IP_NI_SAM7X_ConfigNumRxBuffers() Sets the number of Rx buffers.

Table 13.13: embOS/IP SAM7X driver specific function overview

Parameter Description

NumRxBuffers [IN] The number of Rx buffers.

Table 13.14: IP_NI_SAM7X_ConfigNumRxBuffers() parameter list

231

13.2.3.4 Required BSP functions

13.2.3.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

Parameter

Example

/* Excerpt from implementation for ATMEL AT91SAM7X-EK */

#define AT91C_PMC_PCER (*(volatile unsigned*) 0xFFFFFC10)

#define AT91C_PIOB_PPUDR (*(volatile unsigned*) 0xFFFFF660)

#define AT91C_PIOB_PER (*(volatile unsigned*) 0xFFFFF600)

#define AT91C_PIOB_OER (*(volatile unsigned*) 0xFFFFF610)

#define AT91C_PIOB_CODR (*(volatile unsigned*) 0xFFFFF634)

#define AT91C_PIOB_SODR (*(volatile unsigned*) 0xFFFFF630)

#define AT91C_PIOB_ODR (*(volatile unsigned*) 0xFFFFF614)

#define AT91C_PIOB_PDR (*(volatile unsigned*) 0xFFFFF604)

#define AT91C_RSTC_RMR (*(volatile unsigned*) 0xFFFFFD08)

#define AT91C_PIOB_ASR (*(volatile unsigned*) 0xFFFFF670)

#define AT91C_RSTC_RCR (*(volatile unsigned*) 0xFFFFFD00)

#define AT91C_RSTC_ERSTL (0xF << 8)

#define AT91C_RSTC_EXTRST (0x1 << 3)

#define AT91C_RSTC_NRSTL (1UL << 16)

void BSP_ETH_Init(unsigned Unit) {

unsigned v;

AT91C_PMC_PCER = (1 << _PIOB_ID); // Enable clock for PIOB

AT91C_PIOB_PPUDR = 1UL << 15; // Disable RXDV pullup,

// enter PHY normal mode

AT91C_PIOB_PPUDR = 1UL << 16;

// Init PIO and perform a RESET of PHY since PHY

v = 0

| (1 << 0)

| (1 << 15)

| (1 << 16)

| (1 << 18)

;

AT91C_PIOB_PER = v; // Entire lower 19 bits enabled

AT91C_PIOB_OER = v;

AT91C_PIOB_CODR = 0

| (1 << 7) // 0: node mode, 1: repeater mode

| (1 << 15) // 0: Normal mode, 1: test mode

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.15: embOS/IP driver specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.16: BSP_ETH_Init() parameter list

232 CHAPTER 13 Network interface drivers

| (1 << 16) // 0: MII

| (1 << 18) // 0: Power down

;

AT91C_PIOB_SODR = 0

| (1 << 0) // Isolate

;

// Perform hardware reset using RESET pin of MCU

AT91C_RSTC_RMR = 0xA5000000 | AT91C_RSTC_ERSTL & (1 << 8);

AT91C_RSTC_RCR = 0xA5000000 | AT91C_RSTC_EXTRST;

while ((AT91C_RSTC_RSR & AT91C_RSTC_NRSTL) == 0); // Wait until RESET timer has

// expired

// Switch to peripheral functions

v = 0x3FFFF; // Lower 18 bits are used for the peripheral

AT91C_PIOB_ODR = v; // Entire lower 18 bits disabled

AT91C_PIOB_ASR = v; // Select peripheral A use

AT91C_PIOB_PDR = v; // Disable GPIO mode, select peripheral

}

13.2.3.5 Additional information

None.

233

13.2.4 ATMEL AT91SAM9260

The ATMEL AT91SAM9260 is based on the ARM926EJ-S™ processor. Its peripheral set

includes USB Full Speed Host and Device interfaces, a 10/100 Base T Ethernet MAC,

Image Sensor Interface, Multimedia Card Interface (MCI), Synchronous Serial Con-

trollers (SSC), USARTs, Master/Slave Serial Peripheral Interfaces (SPI), a three-

channel 16-bit Timer Counter (TC), a Two Wire Interface (TWI) and four-channel 10-

bit ADC.

13.2.4.1 Supported hardware

The network interface driver for the AT91SAM9260 can be used with every ATMEL

AT91SAM9260 target board. The driver has been tested on the following eval boards:

13.2.4.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_SAM9260. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_SAM9260); // Add Ethernet driver

IP_SetHWAddr("\x00\x22\xC7\xFF\xFF\xFF"); // MAC addr: Needs to be unique

// for production units

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers.

// The default setup will do for most cases.

IP_AddBuffers(50, 256); // Small buffers.

IP_AddBuffers(50, 1536); // Big buffers. Size should be 1536 to

// allow a full ether packet to fit.

IP_ConfTCPSpace(16 * 1024, 16 * 1024);

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Do not filter:

// Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP);

}

13.2.4.3 Driver specific configuration functions

13.2.4.3.1 IP_NI_SAM9260_ConfigNumRxBuffers

Description

Sets the number of Rx buffers of the driver. This function has to be called in the con-

figuration phase.

Tested evaluation boards

ATMEL AT91SAM9260

Table 13.17: List of tested eval boards

Function Description

IP_NI_SAM9260_ConfigNumRxBuffers() Sets the number of Rx buffers.

Table 13.18: embOS/IP SAM9260 driver specific function overview

234 CHAPTER 13 Network interface drivers

Prototype

void IP_NI_SAM9260_ConfigNumRxBuffers( U16 NumRxBuffers );

Parameter

13.2.4.4 Required BSP functions

13.2.4.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

Parameter

Example

/*********************************************************************

* BSP_ETH_Init()

* Function description

* This function is called from the network interface driver.

* It initializes the network interface. This function should be used

* to enable the ports which are connected to the network hardware.

* It is called from the driver during the initialization process.

* Note:

* (1) If your MAC is connected to the PHY via Media Independent

* Interface (MII) change the macro _USE_RMII and call

* IP_NI_ConfigPHYMode() from within IP_X_Config()

* to change the default of driver.

void BSP_ETH_Init(unsigned Unit) {

unsigned PinsA;

unsigned PinsB;

PMC_PCER = (1 << ID_EMAC_PORT); // Enable clock for PIO

EMAC_PORT_PPUDR = (1 << EMAC_PORT_RXDV_BIT); // Disable RXDV pullup,

// enter PHY normal mode

#if _USE_RMII

EMAC_PORT_PPUER = (1 << EMAC_PORT_RMII_BIT); // Enable Pullup => Switch to RMII.

#else

EMAC_PORT_PPUDR = (1 << EMAC_PORT_RMII_BIT); // Disable Pullup => Switch to MII.

#endif

// Power up PHY, may not be required, if set as hardwired option on target

#ifdef EMAC_PORT_PWR_PHY_BIT

EMAC_PORT_PER = (1 << EMAC_PORT_PWR_PHY_BIT);

Parameter Description

NumRxBuffers [IN] The number of Rx buffers.

Table 13.19: IP_NI_SAM9260_ConfigNumRxBuffers() parameter list

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.20: embOS/IP driver specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.21: BSP_ETH_Init() parameter list

235

EMAC_PORT_OER = (1 << EMAC_PORT_PWR_PHY_BIT);

EMAC_PORT_CODR = (1 << EMAC_PORT_PWR_PHY_BIT);

#endif

// Init PIO Pins: EMAC is connected to specific lines of PIO

PinsA = (1uL << 12)

| (1uL << 13)

| (1uL << 14)

| (1uL << 15)

| (1uL << 16)

| (1uL << 17)

| (1uL << 18)

| (1uL << 19)

| (1uL << 20)

| (1uL << 21)

;

PinsB = (1uL << 10)

| (1uL << 11)

| (1uL << 22)

| (1uL << 25)

| (1uL << 26)

| (1uL << 27)

| (1uL << 28)

| (1uL << 29)

;

EMAC_PORT_ASR = PinsA; // Select peripheral A use

EMAC_PORT_BSR = PinsB; // Select peripheral B use

EMAC_PORT_PDR = PinsA | PinsB; // Disable GPIO mode, select peripheral function

// Initialize priority of BUS MATRIX. EMAC needs highest priority for SDRAM access

MATRIX_SCFG3 = 0x01160030; // Assign EMAC as default master, activate priority

arbitration, increase cycles

MATRIX_PRAS3 = 0x00320000; // Set Priority of EMAC to 3 (highest value)

}

13.2.4.5 Additional information

None.

236 CHAPTER 13 Network interface drivers

13.2.5 DAVICOM DM9000/DM9000A

The Davicom DM9000 is a fully integrated single chip Fast Ethernet MAC controller

with a generic processor interface, a 10/100M PHY and SRAM.

13.2.5.1 Supported hardware

The network interface driver for the Davicom DM9000 can be used with every target

board which complies with the following:

• Davicom DM9000 is presented

• DM 9000 is connected to the data/address bus; data bus is 16-bits wide

• INT pin connected to CPU in a way which allows generating interrupts

The driver has been tested on the following eval boards:

13.2.5.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_DM9000. This function must be called from within IP_X_Config(). Refer

to IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_DM9000); // Add Ethernet driver

IP_NI_DM9000_ConfigAddr(0, (void*) (0x30000000), (void*) (0x30000000 + 0x04));

IP_NI_ConfigPoll(0); // No ISR routine

IP_SetHWAddr("\x00\x22\x33\x44\x55\x66"); // MAC addr: Needs to be unique

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers. The default setup will do for most cases.

IP_AddBuffers(12, 256); // Small buffers.

IP_AddBuffers(12, 1536); // Big buffers. Size should be 1536 to

// allow a full ether packet to fit.

IP_ConfTCPSpace(6 * 1024, 4 * 1024);

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Do not filter:

// Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP );

}

Tested evaluation boards

ATMEL AT91SAM9261-EK

Table 13.22: List of tested eval boards

237

13.2.5.3 Driver-specific configuration functions

13.2.5.3.1 IP_NI_DM9000_ConfigAddr()

Description

Sets the base address (for command) and data address.

Prototype

void IP_NI_DM9000_ConfigAddr( unsigned Unit,

void * pBase,

void * pValue );

Parameter

Additional information

This function must be called from within IP_X_Config. Refer to IP_X_Configure() on

page 256 for detailed information.

13.2.5.3.2 IP_NI_DM9000_ISR_Handler()

Description

This is the interrupt service routine for the network interface (EMAC). It handles all

interrupts (Rx, Tx, Error).

Prototype

void IP_NI_DM9000_ISR_Handler( unsigned Unit );

Parameter

Function Description

IP_NI_DM9000_ConfigAddr() Sets the base address for com-

mands and data register.

IP_NI_DM9000_ISR_Handler() Interrupt service routine for the

network interface.

Table 13.23: embOS/IP DM9000 driver-specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

pBase [IN] Pointer to the control register of the MAC.

pValue [IN] Pointer to the data register of the MAC.

Table 13.24: IP_NI_DM9000_ConfigAddr() parameter list

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.25: IP_NI_DM9000_ISR_Handler() parameter list

238 CHAPTER 13 Network interface drivers

13.2.5.4 Required BSP functions

13.2.5.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

13.2.5.5 Additinal information

None.

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.26: embOS/IP driver specific function overview

239

13.2.6 FREESCALE ColdFire MCF5329

13.2.6.1 Supported hardware

The network interface driver for the ColdFire MCF5329 MCU can be used with every

target board. The driver has been tested on the following eval boards:

13.2.6.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_MCF5329. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

/* Sample implementation taken from the configuration for the ColdFire MCF5329 */

#define ALLOC_SIZE 0xA000 // Size of memory dedicated

// to the stack in bytes

U32 _aPool[ALLOC_SIZE / 4]; // This is the memory area used

// by the stack.

/*********************************************************************

* IP_X_Config

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_MCF5329); // Add ethernet driver

IP_SetHWAddr((const unsigned char *)"\x00\x22\xC7\xFF\xFF\xFF");

// Use DHCP client or define IP address, subnet mask,

// gateway address and DNS server according to the

// requirements of your application.

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// IP_SetAddrMask(0xC0A805E6, 0xFFFF0000); // Assign IP addr. and subnet mask

// IP_SetGWAddr(0, 0xC0A80201); // Set gateway address

// IP_DNS_SetServer(0xCC98B84C); // Set DNS server address,

// for example 204.152.184.76

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers.

// The default setup will do for most cases.

IP_AddBuffers(12, 256); // Small buffers.

IP_AddBuffers(10, 1536); // Big buffers.

IP_ConfTCPSpace(4 * 1024, 4 * 1024); // Define the TCP Tx and Rx window size

// Define log and warn filter

IP_SetWarnFilter(0xFFFFFFFF);

IP_SetLogFilter(IP_MTYPE_INIT

Tested evaluation boards

LOGICPD ZOOM COLDFIRE SDK with MCF5329 Fire Engine

Table 13.27: List of tested eval boards

240 CHAPTER 13 Network interface drivers

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP

);

}

13.2.6.3 Driver-specific configuration functions

None.

13.2.6.4 Required BSP functions

None.

13.2.6.5 Additional information

None.

241

Parameter

Example

/* Excerpt from implementation for the ATMEL AT91SAM9261-EK */

#define _PIOC_ID (4)

#define _PMC_PCER (*(volatile unsigned int*) 0xFFFFF810)

#define _PIOC_PER (*(volatile unsigned int*) 0xFFFFFC00)

#define _PIOC_ODR (*(volatile unsigned int*) 0xFFFFFC14)

#define _PIOC_OER (*(volatile unsigned int*) 0xFFFFFC10)

#define _PIOC_SODR (*(volatile unsigned int*) 0xFFFFFC30)

#define _PIOC_CODR (*(volatile unsigned int*) 0xFFFFFC34)

/*********************************************************************

* BSP_ETH_Init()

void BSP_ETH_Init(unsigned Unit) {

int i;

_PMC_PCER |= (1 << _PIOC_ID); // Enable peripheral clock

_PIOC_PER = (1 << 10) | (1 << 11); // Enable Ports for RESET and Interrupt

_PIOC_OER = (1 << 10); // Switch RESET to output mode

_PIOC_ODR = (1 << 11); // Switch Interrupt to output mode

// Activate & deactivate RESET of Ethernet controller.

// We do this in a loop to allow sufficient time for Controller to get out of RESET

for (i = 0; i < 1000; i++) {

_PIOC_SODR = (1 << 10); // Activate RESET

}

for (i = 0; i < 1000; i++) {

_PIOC_CODR = (1 << 10); // Deactivate RESET

}

13.2.6.6 Additional information

None.

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.28: BSP_ETH_Init() parameter list

242 CHAPTER 13 Network interface drivers

13.2.7 NXP LPC17xx

The NXP LPC17xx MCUs are flash microcontrollers with integrated Ethernet, USB and

CAN interfaces, based on the 32-bit Cortex-M3 processor.

13.2.7.1 Supported hardware

The network interface driver for the NXP 17xx can be used with every NXP LPC17xx

target board. The driver has been tested on the following eval boards:

13.2.7.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_LPC24xx. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

/* Sample implementation taken from the configuration for the NXP LPC2468 */

/*********************************************************************

* IP_X_Config

* Function description

* This function is called by the IP stack during IP_Init().

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_LPC17xx); // Add ethernet driver

IP_SetHWAddr("\x00\x22\x33\x44\x55\x66"); // MAC addr: Needs to be unique

// for production units

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers.

// The default setup will do for most cases.

IP_AddBuffers(6, 256); // Small buffers.

IP_AddBuffers(8, 1536); // Big buffers. Size should be 1536

// to allow a full ether packet to fit.

IP_ConfTCPSpace(6 * 1024, 6 * 1024);

IP_SetWarnFilter(0xFFFFFFFF); // Do not filter: Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

);

}

13.2.7.3 Driver-specific configuration functions

None.

Tested evaluation boards

KEIL MCB1760

IAR LPC1768-SK

EmbeddedArtists LPC1788

Table 13.29: List of tested eval boards

243

13.2.7.4 Required BSP functions

13.2.7.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

Parameter

Example

/* Sample implementation for NXP LPC2468 */

#define PINSEL2 *(volatile unsigned long *)(0xE002C008)

#define PINSEL3 *(volatile unsigned long *)(0xE002C00C)

/*********************************************************************

* ETH_Init

void BSP_ETH_Init(unsigned Unit) {

/*------------------------------------------------------------------------------

* write to PINSEL2/3 to select the PHY functions on P1[17:0]

*-----------------------------------------------------------------------------*/

/* P1.6, ENET-TX_CLK, has to be set for EMAC to address a BUG in

the rev"xx-X" or "xx-Y" silicon(see errata). On the new rev.(xxAY, released

on 06/22/2007), P1.6 should NOT be set. */

if (MAC_MODULEID == 0x39022000) { // Older chip ?

PINSEL2 = 0x50151105; /* Selects P1[0,1,4,6,8,9,10,14,15] */

} else {

PINSEL2 = 0x50150105; /* Selects P1[0,1,4,8,9,10,14,15] */

}

PINSEL3 = (PINSEL3 & ~0x0000000f) | 0x5;

}

13.2.7.5 Additional information

None.

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.30: embOS/IP driver specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.31: BSP_ETH_Init() parameter list

244 CHAPTER 13 Network interface drivers

13.2.8 NXP LPC23xx / 24xx

The NXP LPC23xx and LPC24xx MCU families are flash microcontrollers with inte-

grated Ethernet, USB and CAN interfaces, based on the 32-bit ARM7TDMI-S RISC

processor.

13.2.8.1 Supported hardware

The network interface driver for the NXP LPC23xx and LPC24xx MCUs can be used

with every NXP LPC23xx/LPC24xx target board. The driver has been tested on the

following eval boards:

13.2.8.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_LPC24xx. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

/* Sample implementation taken from the configuration for the NXP LPC2468 */

/*********************************************************************

* IP_X_Config

* Function description

* This function is called by the IP stack during IP_Init().

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_LPC24xx); // Add ethernet driver

IP_SetHWAddr("\x00\x22\x33\x44\x55\x66"); // MAC addr: Needs to be unique

// for production units

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers.

// The default setup will do for most cases.

IP_AddBuffers(6, 256); // Small buffers.

IP_AddBuffers(8, 1536); // Big buffers. Size should be 1536

// to allow a full ether packet to fit.

IP_ConfTCPSpace(6 * 1024, 6 * 1024);

IP_SetWarnFilter(0xFFFFFFFF); // Do not filter: Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

);

}

Tested evaluation boards

KEIL MCB2300

IAR LPC2468 V1.0

EmbeddedArtists LPC2468

Table 13.32: List of tested eval boards

245

13.2.8.3 Driver-specific configuration functions

None.

13.2.8.4 Required BSP functions

13.2.8.4.1 BSP_ETH_Init()

Description

This function is called from the network interface driver. It initializes the network

interface. This function should be used to enable the ports which are connected to

the network hardware. It is called from the driver during the initialization process.

Prototype

void BSP_ETH_Init( unsigned Unit );

Parameter

Example

/* Sample implementation for NXP LPC2468 */

#define PINSEL2 *(volatile unsigned long *)(0xE002C008)

#define PINSEL3 *(volatile unsigned long *)(0xE002C00C)

/*********************************************************************

* ETH_Init

void BSP_ETH_Init(unsigned Unit) {

/*------------------------------------------------------------------------------

* write to PINSEL2/3 to select the PHY functions on P1[17:0]

*-----------------------------------------------------------------------------*/

/* P1.6, ENET-TX_CLK, has to be set for EMAC to address a BUG in

the rev"xx-X" or "xx-Y" silicon(see errata). On the new rev.(xxAY, released

on 06/22/2007), P1.6 should NOT be set. */

if (MAC_MODULEID == 0x39022000) { // Older chip ?

PINSEL2 = 0x50151105; /* Selects P1[0,1,4,6,8,9,10,14,15] */

} else {

PINSEL2 = 0x50150105; /* Selects P1[0,1,4,8,9,10,14,15] */

}

PINSEL3 = (PINSEL3 & ~0x0000000f) | 0x5;

}

13.2.8.5 Additional information

None.

Function Description

BSP_ETH_Init() Initializes the network interface.

Table 13.33: embOS/IP driver specific function overview

Parameter Description

Unit [IN] Zero-based index of available network interfaces.

Table 13.34: BSP_ETH_Init() parameter list

246 CHAPTER 13 Network interface drivers

13.2.9 ST STR912

The ST STR912 is based on the ARM966E-S™ processor. It is a flash microcontroller

with integrated Ethernet, USB and CAN interfaces, AC Motor Control, 4 Timers, ADC,

RTC, and DMA.

13.2.9.1 Supported hardware

The network interface driver for the STR912 can be used with every target ST

STR912 target board. The driver has been tested on the following eval boards:

13.2.9.2 Configuring the driver

Adding the driver to embOS/IP

To add the driver, use IP_AddEtherInterface() with the driver identifier

IP_Driver_STR912. This function must be called from IP_X_Config(). Refer to

IP_AddEtherInterface() on page 46 and IP_X_Configure() on page 256 for more

information.

Example

/* Sample implementation taken from the configuration for the ST STR912 */

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_STR912); // Add Ethernet driver

IP_SetHWAddr("\x00\x22\x33\x44\x55\x66"); // MAC addr: Needs to be unique

// for production units

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers.

// The default setup will do for most cases.

IP_AddBuffers(20, 256); // Small buffers.

IP_AddBuffers(12, 1536); // Big buffers. Size should be 1536

// to allow a full ether packet to fit.

IP_ConfTCPSpace(8 * 1024, 8 * 1024);

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Do not filter:

// Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT

| IP_MTYPE_LINK_CHANGE

| IP_MTYPE_DHCP);

}

13.2.9.3 Driver-specific configuration functions

None.

13.2.9.4 Required BSP functions

None.

Tested evaluation boards

IAR STR912FA development board

Table 13.35: List of tested eval boards

247

13.2.9.5 Additional information

None.

248 CHAPTER 13 Network interface drivers

13.3 Writing your own driver

If you are going to use embOS/IP with your own hardware, you may have to write

your own network interface driver. This section describes which functions are

required and how to integrate your own network interface driver into embOS/IP.

Note: We strongly recommend contacting SEGGER if you need to have a driver

for a particular piece of hardware which is not yet supported. Writing a driver is a dif-

ficult task which requires a thorough understanding of Ethernet, MAC, and PHY.

249

13.3.1 Network interface driver structure

embOS/IP uses a simple structure with function pointers to call the appropriate

driver function for a device. Use the supplied template IP_NI_Template.c for the

implementation.

Data structure

typedef struct IP_HW_DRIVER {

int (*pfInit) ( unsigned Unit );

int (*pfSendPacket) ( unsigned Unit );

int (*pfGetPacketSize) ( unsigned Unit );

int (*pfReadPacket) ( unsigned Unit, U8 * pDest, unsigned NumBytes );

void (*pfTimer) ( unsigned Unit );

int (*pfControl) ( unsigned Unit, int Cmd, void * p );

} IP_HW_DRIVER;

Elements of IP_HW_DRIVER

Example

/* Sample implementation taken from the driver for the ATMEL AT91SAM7X */

/*********************************************************************

* Driver API Table

**********************************************************************

const IP_HW_DRIVER IP_Driver_SAM7X = {

_Init,

_SendPacketIfTxIdle,

_GetPacketSize,

_ReadPacket,

_Timer,

_Control

};

Element Meaning

pfInit Pointer to the initialization function.

pfSendPacket Pointer to the send packet function.

pfGetPacketSize Pointer to the get packet size function.

pfReadPacket Pointer to the read packet function.

pfTimer Optional: Pointer to the timer function.

The routine is called from the stack periodically.

pfControl Pointer to the control function.

Table 13.36: IP_HW_DRIVER - List of structure member variables

Device Driver

Structure

pfInit()

pfSendPackedIfTxIdle() pfReadPacket()

pfTimer()

pfGetPacketSize() pfControl()

250 CHAPTER 13 Network interface drivers

13.3.2 Device driver functions

This section provides descriptions of the network interface driver functions required

by embOS/IP. Note that the names used for these functions are not really relevant

for embOS/IP because the stack accesses them through a structure of function point-

ers.

Function Description

pfControl()

This function is used to implement addi-

tional driver specific control functions. It

can be empty.

pfInit() General initialization function of the

driver.

pfGetPacketSize() Reads buffer descriptors to find out if a

packet has been received.

pfReadPacket() Reads the first packet in the buffer.

pfSendPacketIfTxIdle() Send the next packet in the send queue if

transmitter is idle.

pfTimer() Timer function called by the networking

task, IP_Task(), once per second.

Table 13.37: embOS/IP network interface driver functions

251

13.3.3 Driver template

The driver template IP_NI_Template.c is supplied in the folder Sample\Driver\Tem-

plate\.

Example

/*********************************************************************

* SEGGER MICROCONTROLLER SYSTEME GmbH *

* Solutions for real time microcontroller applications *

**********************************************************************

* *

* www.segger.com Support: support@segger.com *

* *

**********************************************************************

* *

* TCP/IP stack for embedded applications *

* *

**********************************************************************

----------------------------------------------------------------------

File : IP_NI_Template.c

Purpose : Network interface driver template

-------- END-OF-HEADER ---------------------------------------------

#include "IP_Int.h"

/*********************************************************************

* _SetFilter

* Function description

* Sets the MAC filter(s)

* The stack tells the driver which addresses should go thru the filter.

* The number of addresses can generally be unlimited.

* In most cases, only one address is set.

* However, if the NI is in multiple nets at the same time or if multicast is used,

* multiple addresses can be set.

* Notes

* (1) Procedure

* In general, precise filtering is used as far as supported by the hardware.

* If the more addresses need to be filtered than precise address filters are

* available, then the hash filter is used.

* Alternativly, the MAC can be switched to promiscuous mode for simple

* implementations.

static int _SetFilter(IP_NI_CMD_SET_FILTER_DATA * pFilter) {

U32 v;

U32 w;

unsigned i;

unsigned NumAddr;

const U8 * pAddrData;

NumAddr = pFilter->NumAddr;

for (i = 0; i < NumAddr; i++) {

pAddrData = *(&pFilter->pHWAddr + i);

}

return 0; // O.K.

}

/*********************************************************************

* _SendPacket

* Function description

* Send the next packet in the send queue.

* Function is called from 2 places:

* - from a task via pfSendPacketIfTxIdle() in Driver structure

* - from ISR when Tx is completed (TxInterrupt)

static int _SendPacket(void) {

U32 v;

void * pPacket;

unsigned NumBytes;

252 CHAPTER 13 Network interface drivers

IP_GetNextOutPacket(&pPacket, &NumBytes); // Get information about next

// packet in the Queue. 0

// means no packet in queue

if (NumBytes == 0) {

return 0;

}

IP_LOG((IP_MTYPE_DRIVER, "DRIVER: Sending packet: %d bytes", NumBytes));

// Start send

return 0;

}

/*********************************************************************

* _ISR_Handler

* Function description

* This is the interrupt service routine for the NI (EMAC).

* It handles all interrupts (Rx, Tx, Error).

static void _ISR_Handler(void) {

}

/*********************************************************************

* _Init

* Function description

* General init function of the driver.

* Called by the stack in the init phase before any other driver function.

static int _Init(unsigned Unit) {

int r;

r = _PHY_Init(Unit); // Configure the PHY

if (r) {

return 1;

}

// TBD

return 0;

}

/*********************************************************************

* _SendPacketIfTxIdle

* Function description

* Send the next packet in the send queue if transmitter is idle.

* If transmitter is busy, nothing is done since the next packet is sent

* automatically with Tx-interrupt.

* Function is called from a task via function pointer in in driver structure.

static int _SendPacketIfTxIdle(unsigned Unit) {

// TBD

return 0;

}

/*********************************************************************

* _GetPacketSize()

* Function description

* Reads buffer descriptors in order to find out if a packet has been received.

* Different error conditions are checked and handled.

* Function is called from a task via function pointer in driver structure.

* Return value

* Number of buffers used for the next packet.

253

* 0 if no complete packet is available.

static int _GetPacketSize(unsigned Unit) {

// TBD

return 0;

}

/*********************************************************************

* _ReadPacket

* Function description

* Reads the first packet into the buffer.

* NumBytes must be the correct number of bytes as retrieved by _GetPacketSize();

* Function is called from a task via function pointer in driver structure.

static int _ReadPacket(unsigned Unit, U8 *pDest, unsigned NumBytes) {

// TBD

return 0;

}

/*********************************************************************

* _Timer

* Function description

* Timer function called by the Net task once per second.

* Function is called from a task via function pointer in driver structure.

static void _Timer(unsigned Unit) {

// _UpdateLinkState();

}

/*********************************************************************

* _Control

* Function description

* Control function for various purposes.

* Function is called from a task via function pointer in driver structure.

* Return value

* -1: Command is not supported

* !=-1: Command supported. Typically 0 means success,

* but can also be a return value.

static int _Control(unsigned Unit, int Cmd, void * p) {

switch (Cmd) {

case IP_NI_CMD_SET_FILTER:

return _SetFilter((IP_NI_CMD_SET_FILTER_DATA*)p);

case IP_NI_CMD_SET_BPRESSURE:

// TBD: Enable back pressure (if supported) and change return value to 0

break;

case IP_NI_CMD_CLR_BPRESSURE:

// TBD: Disable back pressure (if supported) and change return value to 0

break;

case IP_NI_CMD_GET_MAC_ADDR:

break;

case IP_NI_CMD_GET_CAPS:

// TBD: Retrieves the capabilites, which are a logical-or combination of

// the IP_NI_CAPS (if any)

// {

// int v;

// v = 0

// | IP_NI_CAPS_WRITE_IP_CHKSUM // Driver capable of inserting the

// IP-checksum into an outgoing packet?

254 CHAPTER 13 Network interface drivers

// | IP_NI_CAPS_WRITE_UDP_CHKSUM // Driver capable of inserting the

// UDP-checksum into an outgoing packet?

// | IP_NI_CAPS_WRITE_TCP_CHKSUM // Driver capable of inserting the

// TCP-checksum into an outgoing packet?

// | IP_NI_CAPS_WRITE_ICMP_CHKSUM // Driver capable of inserting the

// ICMP-checksum into an outgoing packet?

// | IP_NI_CAPS_CHECK_IP_CHKSUM // Driver capable of computing and

// comparing the IP-checksum of

// incoming packets?

// | IP_NI_CAPS_CHECK_UDP_CHKSUM // Driver capable of computing and

// comparing the UDP-checksum of an

// incoming packet?

// | IP_NI_CAPS_CHECK_TCP_CHKSUM // Driver capable of computing

// and comparing the TCP-checksum of

// an incoming packet?

// | IP_NI_CAPS_CHECK_ICMP_CHKSUM // Driver capable of computing

// and comparing the ICMP-checksum of

// an incoming packet?

// }

// return v;

break;

case IP_NI_CMD_POLL:

// Poll MAC (typically once per ms) in cases where MAC does not

// trigger an interrupt.

break;

default:

;

}

return -1;

}

/*********************************************************************

* Public API struct

* This is the only public part of the driver.

* All driver functions are called indirectly via this structure

const IP_HW_DRIVER IP_Driver_Template = {

_Init,

_SendPacketIfTxIdle,

_GetPacketSize,

_ReadPacket,

_Timer,

_Control

};

/*************************** End of file ****************************/

255

Chapter 14

Configuring embOS/IP

embOS/IP can be used without changing any of the compile-time flags. All compile-

time configuration flags are preconfigured with valid values, which match the

requirements of most applications. Network interface drivers can be added at runt-

ime.

The default configuration of embOS/IP can be changed via compile-time flags which

can be added to IP_Conf.h. IP_Conf.h is the main configuration file for the TCP/IP

stack.

256 CHAPTER 14 Configuring embOS/IP

14.1 Runtime configuration

Every driver folder includes a configuration file with implementations of runtime con-

figuration functions explained in this chapter. These functions can be customized.

14.1.1 IP_X_Configure()

Description

Helper function to prepare and configure the TCP/IP stack.

Prototype

void IP_X_Config (void);

Additional information

This function is called by the startup code of the TCP/IP stack from IP_Init(). Refer

to IP_Init() on page 79 for more information.

Example

/*********************************************************************

* IP_X_Config

* Function description

* This function is called by the IP stack during IP_Init().

* Typical memory/buffer configurations:

* Microcontroller system, size optimized

* #define ALLOC_SIZE 0x3000 // 12 KBytes RAM

* mtu = 576; // 576 is minimum acc.

* // to RFC, 1500 is max. for Ethernet

* IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

* // for ethernet by default

* IP_AddBuffers(8, 256); // Small buffers.

* IP_AddBuffers(4, mtu + 16); // Big buffers. Size should be mtu

* // + 16 byte for ethernet header

* // (2 bytes type, 2*6 bytes MAC,

* // 2 bytes padding)

* IP_ConfTCPSpace(1 * 1024, 1 * 1024); // Define TCP Tx and Rx window size

* Microcontroller system, speed optimized or multiple connections

* #define ALLOC_SIZE 0x6000 // 24 KBytes RAM

* mtu = 1500; // 576 is minimum acc. to RFC,

* // 500 is max. for Ethernet

* IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

* // for ethernet by default

* IP_AddBuffers(12, 256); // Small buffers.

* IP_AddBuffers(6, mtu + 16); // Big buffers. Size should be mtu

* // + 16 byte for ethernet header

* // (2 bytes type, 2*6 bytes MAC,

* // 2 bytes padding)

* IP_ConfTCPSpace(4 * 1024, 4 * 1024); // Define TCP Tx and Rx window size

* System with lots of RAM

* #define ALLOC_SIZE 0x20000 // 128 KBytes RAM

* mtu = 1500; // 576 is minimum acc. to RFC,

* // 1500 is max. for Ethernet

* IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

* // for ethernet by default

* IP_AddBuffers(50, 256); // Small buffers.

* IP_AddBuffers(50, mtu + 16); // Big buffers. Size should be mtu

* // + 16 byte for ethernet header

* // (2 bytes type, 2*6 bytes MAC,

* // 2 bytes padding)

* IP_ConfTCPSpace(8 * 1024, 8 * 1024); // Define TCP Tx and Rx window size

void IP_X_Config(void) {

IP_AssignMemory(_aPool, sizeof(_aPool)); // Assigning memory

IP_AddEtherInterface(&IP_Driver_STR912); // Add ethernet driver

IP_SetHWAddr("\x00\x22\x33\x44\x55\x66"); // MAC addr: Needs to be unique

// for production units

// Use DHCP client or define IP address, subnet mask,

// gateway address and DNS server according to the

257

// requirements of your application.

IP_DHCPC_Activate(0, "TARGET", NULL, NULL);

// IP_SetAddrMask(0xC0A805E6, 0xFFFF0000); // Assign IP addr. and subnet mask

// IP_SetGWAddr(0, 0xC0A80201); // Set gateway address

// IP_DNS_SetServer(0xCC98B84C); // Set DNS server address,

// for example 204.152.184.76

// Add protocols to the stack

IP_TCP_Add();

IP_UDP_Add();

IP_ICMP_Add();

// Run-time configure buffers.

// The default setup will do for most cases.

IP_AddBuffers(20, 256); // Small buffers.

IP_AddBuffers(8, 1536); // Big buffers. Size should be 1536 to

// allow a full ether packet to fit.

IP_ConfTCPSpace(6 * 1024, 4 * 1024); // Define the TCP Tx and Rx window size

// Define log and warn filter

// Note: The terminal I/O emulation affects the timing

// of your communication, since the debugger stops the target

// for every terminal I/O output unless you use DCC!

IP_SetWarnFilter(0xFFFFFFFF); // 0xFFFFFFFF: Output all warnings.

IP_SetLogFilter(IP_MTYPE_INIT // Output all messages from init

| IP_MTYPE_LINK_CHANGE // Output a msg if link status changes

| IP_MTYPE_DHCP // Output general DHCP status messages

);

}

14.1.2 Driver handling

IP_X_Config() is called at initialization of the TCP/IP stack. It is called by the IP stack

during IP_Init(). IP_X_Config() should help to bundle the process of adding and con-

figuring the driver.

14.1.3 Memory and buffer assignment

The total memory requirements of the TCP/IP stack can basically be computed as the

sum of the following components:

14.1.3.1 RAM for TCP window

The data for the TCP window is typically stored in large buffers. The number of large

buffers required is typically:

RxWindowSize / BigBufferSize

This amount of buffers (and RAM for these buffers) is needed for every simulta-

neously active TCP connection, where "active" means sending & receiving data.

14.1.3.2 Required buffers

Most of the RAM used by the stack is used for packet buffers. Packet buffers are used

to hold incoming and outgoing packets and data in receive and transmit windows of

TCP connections.

Description ROM

IP-Stack core app. 200 bytes

Sockets n * app. 200 bytes

UDP connection n * app. 100 bytes

TCP/ connection n * app. 200 bytes + RAM for TCP Window

258 CHAPTER 14 Configuring embOS/IP

Example configuration - Extremly small (4 Kbytes)

This configuration is the smallest available or at least very close. It is intended to be

used on MCUs with very little RAM and can be used for applications which are

designed for a very low amount of traffic.

#define ALLOC_SIZE 0x1000 // 4 Kbytes RAM

mtu = 576; // 576 is minimum acc.

// to RFC, 1500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

// for ethernet by default

IP_AddBuffers(4, 256); // Small buffers.

IP_AddBuffers(2, mtu + 16); // Big buffers. Size should be mtu

// + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(1 * (mtu-40), 1 * (mtu-40)); // Define TCP Tx and Rx window size

Example configuration - Small (12 Kbytes)

This configuration is a small configuration intended to be used on MCUs with little

RAM and can be used for applications which are designed for a medium amount of

traffic.

#define ALLOC_SIZE 0x3000 // 12 Kbytes RAM

mtu = 576; // 576 is minimum acc.

// to RFC, 1500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

// for ethernet by default

IP_AddBuffers(8, 256); // Small buffers.

IP_AddBuffers(4, mtu + 16); // Big buffers. Size should be mtu

// + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(2 * (mtu-40), 2 * (mtu-40)); // Define TCP Tx and Rx window size

Example configuration - Normal (24 Kbytes)

This configuration is a typical configuration for many MCUs that have a fair amount of

internal RAM. It can be used for applications which are designed for a higher amount

of traffic and/or multiple client connections.

#define ALLOC_SIZE 0x6000 // 24 Kbytes RAM

mtu = 1500; // 576 is minimum acc. to RFC,

// 500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

// for ethernet by default

IP_AddBuffers(12, 256); // Small buffers.

IP_AddBuffers(6, mtu + 16); // Big buffers. Size should be mtu

// + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(3 * (mtu-40), 3 * (mtu-40)); // Define TCP Tx and Rx window size

Example configuration - Large (128 Kbytes)

This configuration is a large configuration intended to be used on MCUs with many

external RAM. It can be used for applications which are designed for a high amount

of traffic and multiple client/server connections at the same time.

#define ALLOC_SIZE 0x20000 // 128 Kbytes RAM

mtu = 1500; // 576 is minimum acc. to RFC,

// 1500 is max. for Ethernet

IP_SetMTU(0, mtu); // Maximum Transmission Unit is 1500

// for ethernet by default

IP_AddBuffers(50, 256); // Small buffers.

IP_AddBuffers(50, mtu + 16); // Big buffers. Size should be mtu

// + 16 byte for ethernet header

// (2 bytes type, 2*6 bytes MAC,

// 2 bytes padding)

IP_ConfTCPSpace(6 * (mtu-40), 6 * (mtu-40)); // Define TCP Tx and Rx window size

259

14.2 Compile-time configuration

The following types of configuration macros exist:

Binary switches "B"

Switches can have a value of either 0 or 1, for deactivated and activated respectively.

Actually, anything other than 0 works, but 1 makes it easier to read a configuration

file. These switches can enable or disable a certain functionality or behavior.

Switches are the simplest form of configuration macros.

Numerical values "N"

Numerical values are used somewhere in the code in place of a numerical constant. A

typical example is the configuration of the sector size of a storage medium.

Function replacements "F"

Macros can basically be treated like regular functions although certain limitations

apply, as a macro is still put into the code as simple text replacement. Function

replacements are mainly used to add specific functionality to a module which is

highly hardware-dependent. This type of macro is always declared using brackets

(and optional parameters).

14.2.1 Compile-time configuration switches

Type Symbolic name Default Description

System configuration macros

NIP_IS_BIGENDIAN -- Macro to define if a big endian tar-

get is used.

Deb ug macros

NIP_DEBUG 0

Macro to define the debug level of

the embOS/IP build. Refer to

Debug level on page 260 for a

description of the different debug

level.

Optimization macros

FIP_CKSUM

IP_cksum

(C- routine in IP

stack)

Macro to define an optimized

checksum routine to speed up the

stack. An optimized checksum rou-

tine is typically implemented in

assembly language.

Optimized versions for the GNU,

IAR and ADS compilers are sup-

plied.

FIP_MEMCPY

memcpy

(C-routine in

standard C-

library)

Macro to define an optimized

memcpy routine to speed up the

stack. An optimized memcpy rou-

tine is typically implemented in

assembly language.

Optimized version for the IAR

compiler is supplied.

FIP_MEMSET

memset

(C-routine in

standard C-

library)

Macro to define an optimized

memset routine to speed up the

stack. An optimized memset rou-

tine is typically implemented in

assembly language.

260 CHAPTER 14 Configuring embOS/IP

14.2.2 Debug level

embOS/IP can be configured to display debug information at higher debug levels to

locate a problem (Error) or potential problem. To display information, embOS/IP uses

the logging routines (see chapter Debugging on page 433). These routines can be

blank, they are not required for the functionality of embOS/IP. In a target system,

they are typically not required in a release (production) build, since a production

build typically uses a lower debug level.

If (IP_DEBUG == 0): used for release builds. Includes no debug options.

If (IP_DEBUG == 1): IP_PANIC() is mapped to IP_Panic().

If (IP_DEBUG >= 2): IP_PANIC() is mapped to IP_Panic() and logging support is

activated.

FIP_MEMMOVE

memmove

(C-routine in

standard C-

library)

Macro to define an optimized

memmove routine to speed up the

stack. An optimized memmove

routine is typically implemented in

assembly language.

FIP_MEMCMP

memcmp

(C-routine in

standard C-

library)

Macro to define an optimized

memcmp routine to speed up the

stack. An optimized memcmp rou-

tine is typically implemented in

assembly language.

Type Symbolic name Default Description

261

Chapter 15

Web server (Add-on)

The embOS/IP web server is an optional extension to embOS/IP. The web server can

be used with embOS/IP or with a different TCP/IP stack. All functions that are

required to add a web server task to your application are described in this chapter.

262 CHAPTER 15 Web server (Add-on)

15.1 embOS/IP web server

The embOS/IP web server is an optional extension which adds the HTTP protocol to

the stack. It combines a maximum of performance with a small memory footprint.

The web server allows an embedded system to present web pages with dynamically

generated content. It comes with all features typically required by embedded sys-

tems: multiple connections, authentication, forms and low RAM usage. RAM usage

has been kept to a minimum by smart buffer handling.

The web server implements the relevant parts of the following Request For Com-

ments (RFC).

The following table shows the contents of the embOS/IP web server root directory:

RFC# Description

[RFC 1945] HTTP - Hypertext Transfer Protocol -- HTTP/1.0

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc1945.txt

[RFC 2616] HTTP - Hypertext Transfer Protocol -- HTTP/1.1

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc2616.txt

Directory Content

Application\ Contains the example application to run

the web server with embOS/IP.

Config

Contains the web server configuration file.

Refer to Configuration on page 283 for

detailed information.

Inc Contains the required include files.

Contains the web server sources,

IP_Webserver.c, IP_Webserver.h and

IP_UTIL_BASE64.c, IP_UTIL.h.

IP\FS\

Contains the sources for the file system

abstraction layer and the read-only file

system. Refer to File system abstraction

layer on page 456 for detailed information.

Windows\Webserver\

Contains the source, the project files and

an executable to run embOS/IP web server

on a Microsoft Windows host. Refer to

Using the web server sample on page 267

for detailed information.

Supplied directory structure of embOS/IP web server package

263

15.2 Feature list

• Low memory footprint.

• Dynamic web pages (Server Side Includes).

• Authentication supported.

• Forms: POST and GET support.

• Multiple connections supported.

• r/o file system included.

• HTML to C converter included.

• Independent of the file system: any file system can be used.

• Independent of the TCP/IP stack: any stack with sockets can be used.

• Demo with authentication, various forms, dynamic pages included.

• Project for executable on PC for Microsoft Visual Studio included.

264 CHAPTER 15 Web server (Add-on)

15.3 Requirements

TCP/IP stack

The embOS/IP web server requires a TCP/IP stack. It is optimized for embOS/IP, but

any RFC-compliant TCP/IP stack can be used. The shipment includes a Win32 simula-

tion, which uses the standard Winsock API and an implementation which uses the

socket API of embOS/IP.

Multi tasking

The web server needs to run as a separate thread. Therefore, a multi tasking system

is required to use the embOS/IP web server.

265

15.4 HTTP backgrounds

It is a communication protocol originally designed to transfer information via hyper-

text pages. The development of HTTP is coordinated by the IETF (Internet Engineer-

ing Task Force) and the W3C (World Wide Web Consortium). The current protocol

version is 1.1.

15.4.1 HTTP communication basics

HTTP is a challenge and response protocol. A client initiates a TCP connection to the

web server and sends a HTTP request. A HTTP request starts with a method token.

[RFC 2616] defines 8 method tokens. The method token indicates the method to be

performed on the requested resource. embOS/IP web server supports all methods

which are typically required by an embedded web server.

The following example shows parts of a HTTP session, where a client (for example,

192.168.1.75) asks the embOS/IP web server for the hypertext page example.html.

The request is followed by a blank line, so that the request ends with a double new-

line, each in the form of a carriage return followed by a line feed.

GET /example.html HTTP/1.1

Host: 192.168.1.75

The first line of every response message is the Status-Line, consisting of the protocol

version followed by a numeric status code. The Status-Line is followed by the con-

tent-type, the server, expiration and the transfer-encoding. The server response ends

with an empty line, followed by length of content that should be transferred. The

length indicates the length of the web page in bytes.

HTTP method Description

GET The GET method means that it retrieves whatever information is

identified by the Request-URI.

HEAD The HEAD method means that it retrieves the header of the content

which is identified by the Request-URI.

POST The POST method submits data to be processed to the identified

resource. The data is included in the body of the request.

Table 15.1: Supported HTTP methods

Application layer

Transport layer

Network layer

Link layer

HTTP

TCP

Ethernet (IEEE 802.3), ...

266 CHAPTER 15 Web server (Add-on)

HTTP/1.1 200 OK

Content-Type: text/html

Server: embOS/IP

Expires: THU, 26 OCT 1995 00:00:00 GMT

Transfer-Encoding: chunked

Thereafter, the web server sends the requested hypertext page to the client. The

zero at the end of the web page followed by an empty line signalizes that the trans-

mission of the requested web page is complete.

<HTML>

<HEAD>

<TITLE>embOS/IP examples</TITLE>

</HEAD>

<BODY>

<H1>Website: example.htm</H1>

</CENTER>

</BODY>

</HTML>

15.4.2 HTTP status codes

The first line of a HTTP response is the Status-Line. It consists of the used protocol

version, a status code and a short textual description of the Status-Code. The Status-

Code element is a 3-digit integer result code of the attempt to understand and satisfy

the request.

The first digit of the Status-Code defines the class of response. The last two digits do

not have any categorization role. There are 5 values for the first digit:

• 1xx: Informational - Request received, continuing process.

• 2xx: Success - The action was successfully received, understood, and accepted.

• 3xx: Redirection - Further action must be taken in order to complete the request.

• 4xx: Client Error - The request contains bad syntax or cannot be fulfilled.

• 5xx: Server Error - The server failed to fulfill an apparently valid request.

Refer to [RFC 2616] for a complete list of defined status-codes. embOS/IP web

server supports a subset of the defined HTTP status codes. The following status

codes are implemented:

Status code Description

200 OK. The request has succeeded.

401 Unauthorized. The request requires user authentication.

404 Not found. The server has not found anything matching the

Request-URI.

501 Not implemented. The server does not support the HTTP method.

503 Service unavailable. The server is currently unable to handle the

request due to a temporary overloading of the server.

Table 15.2: embOS/IP status codes

267

15.5 Using the web server sample

Ready to use examples for Microsoft Windows and embOS/IP are supplied. If you use

another TCP/IP stack, the sample OS_IP_Webserver.c has to be adapted.

The web server itself does not handle multiple connections. This is part of the appli-

cation and is included in the OS_IP_Webserver.c sample.

The sample application opens a port which listens on port 80 until an incoming con-

nection is detected in a parent task that accepts new connections (or rejects them if

no more connections can be accepted).

For each accepted client connection, the parent task creates a child task running

IP_WEBS_Process() in a seperated context that will then process the request of the

connected client (for example a browser). This way the parent task is ready to handle

further incoming connections on port 80.

Therefore the sample uses n client connections + one for the parent task.

Some browsers may open multiple connections and do not even intend to close the

connection. They rather keep the connections open for further data that might be

requested. To give other clients a chance, a special handling is implemented in the

web server.

The embOS/IP web server has two functions for processing a connection in a child

task:

•IP_WEBS_Process(), that allows a connection to stay open even after all data

has been sent from the target. The connection will stay open as long as the client

does not close it.

•IP_WEBS_ProcessLast(), that will close the connection once the target has sent

all data requested. This is used by the web server sample for the last free con-

nection available. This ensures that at least one connection will be available after

it has been served to accept further clients.

In addition to available connections that can be served directly, a feature called

"backlogging" can be used.

This means additional connections will be accepted (SYN/ACK is sent from target) but

not yet processed. They will be processed as soon as a free connection becomes

available once a child task has served the clients request and has been closed.

Connections in backlog will be kept active until the client side sends a reset due to a

possible timeout in the client.

The example application uses a read-only file system to make web pages available.

Refer to File system abstraction layer on page 456 and File system abstraction layer

on page 456 for detailed information about the read-only file system.

268 CHAPTER 15 Web server (Add-on)

15.5.1 Using the Windows sample

If you have MS Visual C++ 6.00 or any later version available, you will be able to

work with a Windows sample project using embOS/IP web server. If you do not have

the Microsoft compiler, an precompiled executable of the web server is also supplied.

Building the sample program

Open the workspace Start_Webserver.dsw with MS Visual Studio (for example, dou-

ble-clicking it). There is no further configuration necessary. You should be able to

build the application without any error or warning message.

The server uses the IP address of the host PC on which it runs. Open a web browser

and connect by entering the IP address of the host (127.0.0.1) to connect to the

web server.

15.5.2 Running the web server example on target hardware

The embOS/IP web server sample application should always be the first step to check

the proper function of the web server with your target hardware.

Add all source files located in the following directories (and their subdirectories) to

your project and update the include path:

• Application

• Config

• Inc

•IP

• IP\IP_FS\FS_RO\

• IP\IP_FS\FS_RO\Generated\

It is recommended that you keep the provided folder structure.

The sample application can be used on the most targets without the need for chang-

ing any of the configuration flags. The server processes up to three connections using

the default configuration.

Note: Three connections mean that the target can handle up to three targets in

parallel, if every target uses only one connection. Because a single web browser

often attempts to open more then one connection to a web server to request the files

(.gif, .jpeg, etc.) which are included in the requested web page, the number of possi-

ble parallel connected targets is less than the number of possible connections.

Every connection is handled in an separate task. Therefore, the web server uses up

to four tasks in the default configuration, one task which listens on port 80 and

accepts connections and three tasks to process the accepted connections. To modify

the number of connections, only the macro MAX_CONNECTIONS has to be modified.

The supplied sample web pages index.htm, embos.htm and stats.htm include

dynamic content, refer to Common Gateway Interface (CGI) on page 270 for detailed

information about the implementation of dynamic content.

269

15.5.3 Changing the file system type

By default, the web server uses the supplied read-only file system. If a real file sys-

tem like emFile should be used to store the web pages, you have to modify the func-

tion _WebServerChildTask() of the example OS_IP_Webserver.c.

/*********************************************************************

* _WebServerChildTask

static void _WebServerChildTask(void * Context) {

long Sock;

int Opt;

_pFS_API = &IP_FS_ReadOnly;

Sock = (long)Context;

Opt = 1;

setsockopt(Sock, SOL_SOCKET, SO_KEEPALIVE, &Opt, sizeof(Opt));

if (_ConnectCnt < MAX_CONNECTIONS) {

IP_WEBS_Process(_Send, _Recv, Context, _pFS_API, &_Application);

} else {

IP_WEBS_ProcessLast(_Send, _Recv, Context, _pFS_API, &_Application);

}

_closesocket(Sock);

_AddToConnectCnt(-1);

OS_Terminate(0);

}

The usage of the read-only file system is configured with the following line:

_pFS_API = &IP_FS_ReadOnly;

To use emFile as file system for your web server application, add the emFile abstrac-

tion layer IP_FS_FS.c to your project and change the line to:

_pFS_API = &IP_FS_FS;

Refer to File system abstraction layer on page 456 and File system abstraction layer

on page 456 for detailed information about the emFile and read-only file system

abstraction layer.

270 CHAPTER 15 Web server (Add-on)

15.6 Dynamic content

embos/IP supports two different approaches to implement dynamic content in your

web server application. A Common Gateway Interface (CGI) like interface for static

HTML pages with dynamic elements and virtual files which are completely generated

from the application.

15.6.1 Common Gateway Interface (CGI)

A Common Gateway Interface (CGI) like interface is used to implement dynamic con-

tent in web pages. Every web page will be parsed by the server each time a request

is received. The server searches the web page for a special tag. In the default config-

uration, the searched tag starts . The tag will

be analyzed and the parameter will be extracted. This parameter specifies a server-

side command and will be given to the user application, which can handle the com-

mand. The following screenshot shows the example page index.htm.

The HTML source for the page includes the following line:

When the web page is requested, the server parses the tag and the parameter

Counter is searched for in an array of structures of type WEBS_CGI. The structure

includes a string to identify the command and a pointer to the function which should

be called if the parameter is found.

typedef struct {

const char * sName; // e.g. "Counter"

void (*pf)(WEBS_OUTPUT * pOutput, const char * sParameters, const char * sValue);

} WEBS_CGI;

In the example, Counter is a valid parameter and the function

_callback_ExecCounter will be called. You need to implement the WEBS_CGI array

and the callback functions in your application.

static const WEBS_CGI _aCGI[] = {

{"Counter" , _callback_ExecCounter },

{"GetOSInfo" , _callback_ExecGetOSInfo},

{"GetIPAddr" , _callback_ExecGetIPAddr},

{NULL}

};

271

ExecCounter() is a simple example of how to use the CGI feature. It returns a string

that includes the value of a variable which is incremented with every call to Exec-

Counter().

void ExecCounter( WEBS_OUTPUT * pOutput,

const char * sParameters,

const char * sValue ) {

char ac[40];

static char Cnt = 1;

sprintf(ac, "You are visitor no.: %d", Cnt);

IP_WEBS_SendString(pOutput, ac);

Cnt++;

}

If the web page includes the CGI tag followed by an unknown command (for exam-

ple, a typo like COounter instead of Counter in the source code of the web page) an

error message will be sent to the client.

15.6.1.1 Add new CGI functions to your web server application

To define new CGI functions, three things have to be done.

1. Add a new command name which should be used as tag to the WEBS_CGI structure.

For example: UserCGI

static const WEBS_CGI _aCGI[] = {

{"Counter" , _callback_ExecCounter },

{"GetOSInfo" , _callback_ExecGetOSInfo},

{"GetIPAddr" , _callback_ExecGetIPAddr},

{"UserCGI" , _callback_ExecUserCGI },

{NULL}

};

2. Implement the new function in your application source code.

void _callback_ExecUserCGI( WEBS_OUTPUT * pOutput,

const char * sParameters

const char * sValue ) {

/* Add application code here */

}

3. Add the new tag to the source code of your web page:

272 CHAPTER 15 Web server (Add-on)

15.6.2 Virtual files

embOS/IP supports virtual files. A virtual file is not a real file which is stored in the

used file system. It is a function which is called instead. The function generates the

content of a file and sends it to the client.

The web server checks the extension of all requested files, the extension .cgi is by

default used for virtual files. To change the extension that is used to detect a virtual

file, refer to IP_WEBS_SetFileInfoCallback() on page 294 for detailed information.

The embOS/IP web server comes with an example (CallVirtualFile.htm) that

requests a virtual file. The sample web page contains a form with two input test

fields, named FirstName and LastName, and a button to transmit the data to the

server.

When the button on the web page is pressed, the file Send.cgi is requested. The

embOS/IP Web server recognizes the extension .cgi, checks if a virtual file with the

name Send.cgi is defined and calls the defined function. The function in the example

is _callback_SendCGI and gets the string FirstName=Foo&LastName=Bar as parame-

ter.

typedef struct {

const char * sName;

void (*pf)(WEBS_OUTPUT * pOutput, const char * sParameters);

} WEBS_VFILES;

In the example, Send.cgi is a valid URI and the function _callback_SendCGI will be

called.

static const WEBS_VFILES _aVFiles[] = {

{"Send.cgi", _callback_SendCGI },

NULL

};

The virtual file Send.cgi gets two parameters. The strings entered in the input fields

Firstname and LastName are transmitted with the URI. For example, you enter Foo in

the first name field and Bar for last name and push the button. The browser will

transmit the following string to our web server:

Send.cgi?FirstName=Foo&LastName=Bar

You can parse the string and use it in the way you want to. In the example we parse

the string and output the values on a web page which is build from the function

_callback_SendCGI().

static void _callback_SendCGI(WEBS_OUTPUT * pOutput, const char * sParameters) {

char aPara0[32];

char aValue0[32];

char aPara1[32];

char aValue1[32];

int r;

273

IP_WEBS_SendString(pOutput, "<HTML><HEAD><TITLE>CGI Sample</TITLE></HEAD>");

IP_WEBS_SendString(pOutput, "<style type=\"text/css\">

H1, H2, H3, H4 { color: blue }

H1, H2, H3, H4, H5 {font-family: Helvetica;}

PRE {color: black; margin-left: 2%; font-size=150%}

BODY {color: black; margin-left: 2%; }

</style>");

IP_WEBS_SendString(pOutput, "<HR><H2>CGI Sample</H2><HR><BODY>First name: ");

r = IP_WEBS_GetParaValue(sParameters, 0, aPara0,

sizeof(aPara0), aValue0, sizeof(aValue0));

if (r == 0) {

IP_WEBS_SendString(pOutput, aValue0);

}

IP_WEBS_SendString(pOutput, "<BR>Last name: ");

r = IP_WEBS_GetParaValue(sParameters, 1, aPara1,

sizeof(aPara1), aValue1, sizeof(aValue1));

if (r == 0) {

IP_WEBS_SendString(pOutput, aValue1);

}

IP_WEBS_SendString(pOutput, "<BR>");

IP_WEBS_SendString(pOutput, "<HR><CENTER>

</CENTER><IMG SRC=\"segger.gif\">  

<A HREF=\"http://www.segger.com\">www.segger.com</A>

</BODY></HTML>");

}

The output of _callback_SendCGI() should be similar to:

274 CHAPTER 15 Web server (Add-on)

15.7 Authentication

“HTTP/1.0”, includes the specification for a Basic Access Authentication scheme. The

basic authentication scheme is a non-secure method of filtering unauthorized access

to resources on an HTTP server, because the user name and password are passed

over the network as clear text. It is based on the assumption that the connection

between the client and the server can be regarded as a trusted carrier. As this is not

generally true on an open network, the basic authentication scheme should be used

accordingly.

The basic access authentication scheme is described in:

The “basic” authentication scheme is based on the model that the client must

authenticate itself with a user-ID and a password for each realm. The realm value

should be considered an opaque string which can only be compared for equality with

other realms on that server. The server will service the request only if it can validate

the user-ID and password for the protection space of the Request-URI. There are no

optional authentication parameters.

Upon receipt of an unauthorized request for a URI within the protection space, the

server should respond with a challenge like the following:

WWW-Authenticate: Basic realm="Embedded web server"

where "embOS/IP embedded web server" is the string assigned by the server to

identify the protection space of the Request-URI. To receive authorization, the client

sends the user-ID and password, separated by a single colon (":") character, within a

base64 encoded string in the credentials.

If the user agent wishes to send the user-ID “user” and password “pass”, it would

use the following header field:

Authorization: Basic dXNlcjpwYXNz

RFC# Description

[RFC 2617] HTTP Authentication: Basic and Digest Access Authentication

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc2617.txt

275

15.7.1 Authentication example

The client requests a resource for which authentication is required:

GET /conf/Authen.htm HTTP/1.1

Host: 192.168.1.75

The server answers the request with a "401 Unauthorized" status page. The header

of the 401 error page includes an additional line WWW-Authenticate. It includes the

realm for which the proper user name and password should be transmitted from the

client (for example, a web browser).

HTTP/1.1 401 Unauthorized

Date: Mon, 04 Feb 2008 17:00:44 GMT

Server: embOS/IP

Accept-Ranges: bytes

Content-Length: 695

Connection: close

Content-Type: text/html

X-Pad: avoid browser bug

WWW-Authenticate: Basic realm="embOS/IP embedded web server"

<HTML>

<HEAD><TITLE>401 Unauthorized</TITLE></HEAD>

<BODY>

<H1>401 Unauthorized</H1>

Browser not authentication-capable or authentication failed.<P>

</BODY>

</HTML>

The client interprets the header and opens a dialog box to enter the user name and

password combination for the realm of the resource.

Note: The embOS/IP web server example always uses the following user name

and the password combination: User Name: user - Password: pass

Enter the proper user name/password combination for the requested realm and con-

firm with the OK button. The client encodes the user name/password combination to

a base64 encoded string and requests the resource again. The request header is

enhanced by the following line: Authorization: Basic dXNlcjpwYXNz

GET /conf/Authen.htm HTTP/1.1

Host: 192.168.1.75

Authorization: Basic dXNlcjpwYXNz

The server decodes the user name/password combination and checks if the decoded

string matches to the defined user name/password combination of the realm. If the

strings are identical, the server delivers the page. If the strings are not identical, the

server answers again with a "401 Unauthorized" status page.

276 CHAPTER 15 Web server (Add-on)

HTTP/1.1 200 OK

Content-Type: text/html

Server: embOS/IP

Expires: THU, 26 OCT 1995 00:00:00 GMT

Transfer-Encoding: chunked

200

<HTML>

<HEAD>

<TITLE>web server configuration</TITLE>

</HEAD>

<BODY>

</BODY>

</HTML>

15.7.2 Configuration of the authentication

The embOS/IP web server checks the access rights of every resource before return-

ing it. The user can define different realms to separate different parts of the web

server resources. An array of WEBS_ACCESS_CONTROL structures has to be implemented

in the user application. Refer to Structure WEBS_ACCESS_CONTROL on page 312 for

detailed information about the elements of the WEBS_ACCESS_CONTROL structure. If no

authentication should be used, the array includes only one entry for the root path.

WEBS_ACCESS_CONTROL _aAccessControl[] = {

{ "/", NULL, NULL },

};

To define a realm "conf", an additional WEBS_ACCESS CONTROL entry has to be imple-

mented.

WEBS_ACCESS_CONTROL _aAccessControl[] = {

{ "/conf/", "Login for configuration", "user:pass" },

{ "/", NULL, NULL },

};

The string "Login for configuration" defines the realm. "user:pass" is the user

name/password combination stored in one string.

277

15.8 Form handling

The embOS/IP web server supports both POST and GET actions to receive form data

from a client. POST submits data to be processed to the identified resource. The data

is included in the body of the request. GET is normally only used to requests a

resource, but it is also possible to use GET for actions in web applications. Data pro-

cessing on server side might create a new resource or update existing resources or

both.

Every HTML form consists of input items like textfields, buttons, checkboxes, etc.

Each of these input items has a name tag. When the user places data in these items in

the form, that information is encoded into the form data. Form data is a stream of

<name>=<value> pairs separated by the "&" character. The value each of the input

item is given by the user is called the value. The <name>=<value> pairs are URL

encoded, which means that spaces are changed into "+" and special characters are

encoded into hexadecimal values. Refer to [RFC 1738] for detailed information about

URL encoding. The parsing and decoding of form data is handled by the embOS/IP

web server. Thereafter, the server calls a callback function with the decoded and

parsed strings as parameters. The responsibility to implement the callback function is

on the user side.

Valid characters for CGI function names:

•A-Z

•a-z

•0-9

•. _ -

Valid characters for CGI parameter values:

•A-Z

•a-z

•0-9

• All URL encoded characters

• . _ - *()!$\

278 CHAPTER 15 Web server (Add-on)

15.8.1 Simple form processing sample

The following example shows the handling of the output of HTML forms with your web

server application. The example web page ExampleGET.htm implements a form with

three inputs, two text fields and one button.

The HTML code of the web page as it is added to the server is listed below:

<html>

<head><title>embOS/IP web server form example</title></head>

<body>

<p>

First name:

<input name="FirstName"

type="text" size="30"

maxlength="30"

value=""

<br>

Last name:

<input name="LastName"

type="text"

size="30"

maxlength="30"

value=""

<br>

</p>

</form>

</body>

</html>

The action field of the form can specify a resource that the browser should reference

when it sends back filled-in form data. If the action field defines no resource, the

current resource will be requested again.

If you request the web page from the embOS/IP web server and check the source of

the page in your web browser, the CGI parts "" and

"" will be executed before the page will be transmit-

ted to the server, so that in the example the values of the value= fields will be empty

strings.

The HTML code of the web page as seen by the web browser is listed below:

<html>

<head><title>embOS/IP web server form example</title></head>

<body>

<p>

First name:

<input name="FirstName"

type="text" size="30"

maxlength="30"

value=""

<br>

Last name:

<input name="LastName"

type="text"

size="30"

maxlength="30"

value=""

<br>

</p>

</form>

</body>

</html>

279

To start form processing, you have to fill in the FirstName and the LastName field

and click the Send button. In the example, the browser sends a GET request for the

resource referenced in the form and appends the form data to the resource name as

an URL encoded string. The form data is separated from the resource name by "?".

Every <name>=<value> pair is separated by "&".

For example, if you type in the FirstName field John and Doe in the LastName field

and confirm the input by clicking the Send button, the following string will be trans-

mitted to the server and shown in the address bar of the browser.

http://192.168.1.230/ExampleGET.htm?FirstName=John&LastName=Doe

Note: If you use POST as HTTP method, the name>=<value> pairs are not shown

in the address bar of the browser. The <name>=<value> pairs are in this case included

in the entity body.

The embOS/IP web server parses the form data. The <name> field specifies the name

of a CGI function which should be called to process the <value> field. The server

checks therefore if an entry is available in the WEBS_CGI array.

static const WEBS_CGI _aCGI[] = {

{"FirstName", _callback_ExecFirstName},

{"LastName", _callback_ExecLastName },

{NULL}

};

If an entry can be found, the specified callback function will be called.

The callback function for the parameter FirstName is defined as follow:

/*********************************************************************

* Static data

**********************************************************************

static char _acFirstName[12];

/*********************************************************************

* _callback_FirstName

static void _callback_ExecFirstName( WEBS_OUTPUT * pOutput,

const char * sParameters,

const char * sValue ) {

if (sValue == NULL) {

IP_WEBS_SendString(pOutput, _acFirstName);

} else {

_CopyString(_acFirstName, sValue, sizeof(_acFirstName));

}

The function returns a string if sValue is NULL. If sValue is defined, it will be written

into a character array. Because HTTP transmission methods GET and POST only trans-

mit the value of filled input fields, the same function can be used to output a stored

value of an input field or to set a new value. The example web page shows after

entering and transmitting the input the new values of FirstName and LastName as

value in the input fields.

The source of the web page as seen by the web browser is listed below:

280 CHAPTER 15 Web server (Add-on)

<html>

<head><title>embOS/IP web server form example</title></head>

<body>

<p>

First name:

<input name="FirstName"

type="text" size="30"

maxlength="30"

value="John"

<br>

Last name:

<input name="LastName"

type="text"

size="30"

maxlength="30"

value="Doe"

<br>

</p>

</form>

</body>

</html>

281

15.9 File upload

The embOS/IP web server supports file uploads from the client. For this to be possi-

ble a real file system has to be used and the define WEBS_SUPPORT_UPLOAD has to be

defined to “1“.

From the application side uploading a file in general is the same as for other form

data as described in Form handling on page 277. For file uploading a <form> field

with encoding of type multipart/form-data is needed. An upload form field

may contain additional input fields that will be parsed just as if using

a non upload formular and can be parsed in your callback using

IP_WEBS_GetParaValue() on page 301 or by using IP_WEBS_GetParaValuePtr() on

page 302.

15.9.1 Simple form upload sample

The following example shows the handling of file uploads with your web server appli-

cation. The example web page Upload.htm implements a form with a file upload

field.

The HTML code of the web page as it is added to the server is listed below:

<HTML>

<BODY>

<P>

<p>Select a file: <input name="Data" type="file">

</p>

</form>

</P>

</CENTER>

</BODY>

</HTML>

The action field of the form can specify a resource that the browser should reference

when it has finished handling the file upload. If the action field defines no resource,

the current resource will be requested again.

To upload a file, you have to select a file by using the browse button and select a file

to upload and click the Send button. In the example, the browser sends a POST

request for the resource referenced in the form and appends the form and file data in

an encoded string.

The embOS/IP web server parses additional form data passed besides the file to be

uploaded. This works the same as handling form data described in Form handling on

page 277. The action parameter of the <form> field specifies the name of a virtual

file that should be processed. A callback can then be used to provide an answer page

referring the state of the upload. The example below shows how to check the success

of an upload using a virtual file prvided by the WEBS_VFILES array:

static const WEBS_VFILES _aVFiles[] = {

{"Upload.cgi", _callback_CGI_UploadFile },

{ NULL, NULL }

};

If an entry can be found, the specified callback function will be called.

282 CHAPTER 15 Web server (Add-on)

The callback function for the file Upload.cgi is defined as follow:

/*********************************************************************

* Static data

**********************************************************************

/*********************************************************************

* _callback_CGI_UploadFile

static void _callback_CGI_UploadFile(WEBS_OUTPUT * pOutput, const char *

sParameters) {

int r;

const char * pFileName;

int FileNameLen;

const char * pState; // Can be 0: Upload failed; 1: Upload succeeded;

Therefore we do not need to know the length, it will always be 1.

IP_WEBS_SendString(pOutput, "<HTML><BODY>");

r = IP_WEBS_GetParaValuePtr(sParameters, 0, NULL, 0, &pFileName, &FileNameLen);

r |= IP_WEBS_GetParaValuePtr(sParameters, 1, NULL, 0, &pState , NULL);

if (r == 0) {

IP_WEBS_SendString(pOutput, "Upload of \"");

IP_WEBS_SendMem(pOutput, pFileName, FileNameLen);

if (*pState == '1') {

IP_WEBS_SendString(pOutput, "\" successful!<br>");

IP_WEBS_SendString(pOutput, "<a href=\"");

IP_WEBS_SendMem(pOutput, pFileName, FileNameLen);

IP_WEBS_SendString(pOutput, "\">Go to ");

IP_WEBS_SendMem(pOutput, pFileName, FileNameLen);

IP_WEBS_SendString(pOutput, "</a><br>");

} else {

IP_WEBS_SendString(pOutput, "\" not successful!<br>");

}

} else {

IP_WEBS_SendString(pOutput, "Upload not successful!");

}

IP_WEBS_SendString(pOutput, "</BODY></HTML>");

}

In addition to the provided form fields from the upload form used two additional

entries will be added to the end of the parameter list available for parsing:

• The original filename of the file uploaded

• The status of the upload process. This can be 0: Upload failed or 1: Upload suc-

ceeded.

The example web page shows after the upload has been finished.

The source of the web page as seen by the web browser is listed below:

Upload of "1.gif" successful!<br>

</BODY></HTML>

283

15.10 Configuration

The embOS/IP web server can be used without changing any of the compile time

flags. All compile time configuration flags are preconfigured with valid values, which

match the requirements of most applications.

The following types of configuration macros exist:

Binary switches "B"

Switches can have a value of either 0 or 1, for deactivated and activated respectively.

Actually, anything other than 0 works, but 1 makes it easier to read a configuration

file. These switches can enable or disable a certain functionality or behavior.

Switches are the simplest form of configuration macros.

Numerical values "N"

Numerical values are used somewhere in the source code in place of a numerical con-

stant. A typical example is the configuration of the sector size of a storage medium.

Alias "A"

A macro which operates like a simple text substitute. An example would be the define

U8, which the preprocessor would replace with unsigned char.

Function replacements "F"

Macros can basically be treated like regular functions although certain limitations

apply, as a macro is still put into the source code as simple text replacement. Func-

tion replacements are mainly used to add specific functionality to a module which is

highly hardware-dependent. This type of macro is always declared using brackets

(and optional parameters).

15.10.1 Compile time configuration switches

Type Symbolic name Default Description

FWEBS_WARN --

Defines a function to output warn-

ings. In debug configurations (DEBUG

== 1) WEBS_WARN maps to

IP_Warnf_Application().

FWEBS_LOG --

Defines a function to output logging

messages. In debug configurations

(DEBUG == 1) WEBS_LOG maps to

IP_Logf_Application().

NWEBS_IN_BUFFER_SIZE 512

Defines the size of the input buffer.

The input buffer is used to store the

HTTP client requests.

NWEBS_OUT_BUFFER_SIZE 512

Defines the size of the output buffer.

The output buffer is used to store the

HTTP response.

NWEBS_PARA_BUFFER_SIZE 256

Defines the size of the buffer used to

store the parameter/value string that

is given to a virtual file. If virtual files

are not used in your application,

remove the definition from

WEBS_Conf.h to save RAM.

NWEBS_TEMP_BUFFER_SIZE 256 Defines the size of the TEMP buffer

used internally by the web server.

284 CHAPTER 15 Web server (Add-on)

Status message web pages

The status message web pages are visualizations of the information transmitted to

the client in the header of the web server response. Because these visualizations are

not required for the functionality of the web server, the macros can be empty.

NWEBS_AUTH_BUFFER_SIZE 32

Defines the size of the buffer used to

store the authentication string. Refer

to Authentication on page 274 for

detailed information about authenti-

cation.

NWEBS_FILENAME_BUFFER_SIZE 32 Defines the size of the buffer used to

store the filename strings.

BWEBS_SUPPORT_UPLOAD 0/1

Defines if file upload is enabled.

Defaults to 0: Not enabled, for source

code shipments and 1: Enabled, for

object shipments.

Type Symbolic name Default

AWEBS_401_PAGE

"<HTML>\n" \

"<HEAD>\n" \

"<TITLE>401 Unauthorized</TITLE>\n" \

</HEAD>\n" \

"<BODY>\n" \

"<H1>401 Unauthorized</H1>\n" \

"Browser not authentication-capable" \

"or authentication failed.\n" \

"</BODY>\n" \

"</HTML>\n"

Type Symbolic name Default Description

285

AWEBS_404_PAGE

"<HTML>\n" \

"<HEAD>\n" \

"<TITLE>404 Not Found</TITLE>\n" \

</HEAD>\n" \

"<BODY>\n" \

"<H1>404 Not Found</H1>\n" \

"The requested document was not " \

"found on this server.\n" \

"</BODY>\n" \

"</HTML>\n"

AWEBS_501_PAGE

"<HTML>\n" \

"<HEAD>\n" \

"<TITLE>501 Not implemented</TITLE>\n" \

</HEAD>\n" \

"<BODY>\n" \

"<H1>Command is not implemented</H1>\n" \

"</BODY>\n" \

"</HTML>\n"

AWEBS_503_PAGE

"<HTML>\n" \

"<HEAD>\n" \

"<TITLE>503 Connection limit reached</TITLE>\n" \

</HEAD>\n" \

"<BODY>\n" \

"<H1>503 Connection limit reached</H1>\n" \

"The max. number of simultaneous connections to "

"this server reached.<P>\n" \

"Please try again later.\n" \

"</BODY>\n" \

"</HTML>\n"

Type Symbolic name Default

286 CHAPTER 15 Web server (Add-on)
UM07001 User & Reference Guide for embOS/IP © 2007 - 2012 SEGGER Microcontroller GmbH & Co. KG
15.11 API functions
Function Description
IP_WEBS_Process() Processes a HTTP request of a client.
IP_WEBS_ProcessLast() Processes a HTTP request of a client and 
closes the connection thereafter.
IP_WEBS_OnConnectionLimit() Outputs an error message to the connected 
client.
IP_WEBS_SendMem() Sends data to a connected target.
IP_WEBS_SendString() Sends a string to a connected target.
IP_WEBS_SendStringEnc() Encodes and sends a string to a connected 
target.
IP_WEBS_SendUnsigned() Sends an unsigned value to a connected 
target.
IP_WEBS_SetFileInfoCallback() Sets a callback function to handle file infor-
mation used by the web server.
IP_WEBS_AddFileTypeHook() Adds a new file anme extension to MIME 
type correlation.
IP_WEBS_ConfigSendVFileHeader() Configures automatic sending of a header 
based on the file name for virtual files.
IP_WEBS_ConfigSendVFileHookHeade
r()
Configures automatic sending of a header 
based on the file name for VFile hooks.
IP_WEBS_SendHeader() Sends a header with data provided.
CGI/virtual file related functions
IP_WEBS_CompareFileNameExt() Checks the file name extension.
IP_WEBS_GetNumParas() Returns the number of parameter/value 
pairs.
IP_WEBS_GetParaValue() Gets a parameter value pair.
IP_WEBS_DecodeAndCopyStr() Decodes an HTML encoded string and copy 
it into a buffer.
IP_WEBS_DecodeString() Decodes an HTML encoded string.
IP_WEBS_AddVFileHook() Adds a hook to serve a simple virtual file.
Utility functio ns
IP_UTIL_BASE64_Decode() Decodes a Base64 encoded string.
IP_UTIL_BASE64_Encode() Encodes a string as a Base64 string.
Table 15.3: embOS/IP web server interface function overview

287

15.11.1 IP_WEBS_Process()

Description

Processes a HTTP request of a client.

Prototype

int IP_WEBS_Process ( IP_WEBS_tSend pfSend,

IP_WEBS_tReceive pfReceive,

void * pConnectInfo,

const IP_WEBS_FS_API * pFS_API

const WEBS_APPLICATION * pApplication);

Parameter

Return value

0 OK.

Additional Information

This function is part of the thread functionality of the web server. The following types

are used as function pointers to the routines used to send and receive bytes from/to

the client:

typedef int (*IP_WEBS_tSend) (const unsigned char * pData,

int len,

void * pConnectInfo);

typedef int (*IP_WEBS_tReceive) (const unsigned char * pData,

int len,

void * pConnectInfo);

The send and receive functions should return the number of bytes successfully sent/

received to/from the client. The pointer pConnectInfo is passed to the send and

receive routines. It can be used to pass a pointer to a structure containing connec-

tion information or to pass a socket number. For details about the parameter pFS_API

and the IP_WEBS_FS_API structure, refer to File system abstraction layer on

page 456. For details about the parameter pApplication and the WEBS_APPLICATION

structure, refer to Structure WEBS_APPLICATION on page 313.

Refer to IP_WEBS_ProcessLast() on page 288 and IP_WEBS_OnConnectionLimit() on

page 289 for further information.

Parameter Description

pfSend [IN] Pointer to the function to be used by the server to send data to

the client.

pfReceive [IN] Pointer to the function to be used by the server to receive data

from the client.

pConnectInfo [IN] Pointer to the connection information.

pFS_API [IN] Pointer to the used file system API.

pApplication [IN] Pointer to a structure of type WEBS_APPLICATION.

Table 15.4: IP_WEBS_Process() parameter list

288 CHAPTER 15 Web server (Add-on)

15.11.2 IP_WEBS_ProcessLast()

Description

Processes a HTTP request of a client and closes the connection thereafter.

Prototype

int IP_WEBS_Process ( IP_WEBS_tSend pfSend,

IP_WEBS_tReceive pfReceive,

void * pConnectInfo,

const IP_WEBS_FS_API * pFS_API

const WEBS_APPLICATION * pApplication);

Parameter

Return value

0 OK.

Additional Information

This function is part of the thread functionality of the web server. This is typically

called for the last available connection. In contrast to IP_WEBS_Process(), this func-

tion closes the connection as soon as the command is completed in order to not block

the last connection longer than necessary and avoid connection-limit errors.

The following types are used as function pointers to the routines used to send and

receive bytes from/to the client:

typedef int (*IP_WEBS_tSend) (const unsigned char * pData,

int len,

void * pConnectInfo);

typedef int (*IP_WEBS_tReceive) (const unsigned char * pData,

int len,

void * pConnectInfo);

The send and receive functions should return the number of bytes successfully sent/

received to/from the client. The pointer pConnectInfo is passed to the send and

receive routines. It can be used to pass a pointer to a structure containing connec-

tion information or to pass a socket number. For details about the parameter pFS_API

and the IP_WEBS_FS_API structure, refer to File system abstraction layer on

page 456. For details about the parameter pApplication and the WEBS_APPLICATION

structure, refer to Structure WEBS_APPLICATION on page 313.

Refer to IP_WEBS_Process() on page 287 and IP_WEBS_OnConnectionLimit() on

page 289 for further information.

Parameter Description

pfSend [IN] Pointer to the function to be used by the server to send data to

the client.

pfReceive [IN] Pointer to the function to be used by the server to receive data

from the client.

pConnectInfo [IN] Pointer to the connection information.

pFS_API [IN] Pointer to the used file system API.

pApplication [IN] Pointer to a structure of type WEBS_APPLICATION.

Table 15.5: IP_WEBS_Process() parameter list

289

15.11.3 IP_WEBS_OnConnectionLimit()

Description

Outputs an error message to the connected client.

Prototype

void IP_WEBS_OnConnectionLimit( const IP_WEBS_API * pIP_API,

void * CtrlSock );

Parameter

Additional information

This function is typically called by the application if the connection limit is reached.

The structure type IP_WEBS_API contains mappings of the required socket functions

to the actual IP stack. This is required because the socket functions are slightly dif-

ferent on different systems. Refer to IP_WEBS_Process() on page 287 and

IP_WEBS_ProcessLast() on page 288 for further information.

Example

Pseudo code:

// Call IP_WEBS_Process() or IP_WEBS_ProcessLast() if multiple or just

// one more connection is available

do {

if (NumAvailableConnections > 1) {

IP_WEBS_Process();

return;

} else if (NumAvailableConnections == 1) {

IP_WEBS_ProcessLast();

return;

}

Delay();

} while (!Timeout)

// No connection available even after waiting => Output error message

IP_WEBS_OnConnectionLimit();

Parameter Description

pIP_API [IN] Pointer to a structure of type IP_FTPS_API.

CtrlSock [IN] Pointer to the socket which is related to the command connec-

tion.

Table 15.6: IP_WEBS_OnConnectionLimit() parameter list

290 CHAPTER 15 Web server (Add-on)

15.11.4 IP_WEBS_SendMem()

Description

Sends data to a connected target.

Prototype

int IP_WEBS_SendMem ( WEBS_OUTPUT * pOutput,

const char * s,

unsigned NumBytes);

Parameter

Return value

0 OK.

Parameter Description

pOutput [IN] Pointer to the WEBS_OUTPUT structure.

s[IN] Pointer to a memory location that should be transmitted.

NumBytes [IN] Number of bytes that should be sent.

Table 15.7: IP_WEBS_SendMem() parameter list

291

15.11.5 IP_WEBS_SendString()

Description

Sends a zero-terminated string to a connected target.

Prototype

int IP_WEBS_SendString( WEBS_OUTPUT * pOutput,

const char * s);

Parameter

Return value

0 OK.

Parameter Description

pOutput [IN] Pointer to the WEBS_OUTPUT structure.

s[IN] Pointer to a string that should be transmitted.

Table 15.8: IP_WEBS_SendString() parameter list

292 CHAPTER 15 Web server (Add-on)

15.11.6 IP_WEBS_SendStringEnc()

Description

Encodes and sends a zero-terminated string to a connected target.

Prototype

int IP_WEBS_SendString( WEBS_OUTPUT * pOutput,

const char * s);

Parameter

Return value

0 OK.

Additional information

This function encodes the string s with URL encoding, which means that spaces are

changed into "+" and special characters are encoded to hexadecimal values. Refer to

[RFC 1738] for detailed information about URL encoding.

Parameter Description

pOutput [IN] Pointer to the WEBS_OUTPUT structure.

s[IN] Pointer to a string that should be transmitted.

Table 15.9: IP_WEBS_SendStringEnc() parameter list

293

15.11.7 IP_WEBS_SendUnsigned()

Description

Sends an unsigned value to the client.

Prototype

int IP_WEBS_SendUnsigned ( WEBS_OUTPUT * pOutput,

unsigned v,

unsigned Base,

int NumDigits );

Parameter

Return value

0 OK.

Parameter Description

pOutput [IN] Pointer to the WEBS_OUTPUT structure.

s[IN] Value that should be sent.

Base [IN] Numerical base.

NumDigits [IN] Number of digits that should be sent. 0 can be used as a wild-

card.

Table 15.10: IP_WEBS_SendUnsigned() parameter list

294 CHAPTER 15 Web server (Add-on)

15.11.8 IP_WEBS_SetFileInfoCallback()

Description

Sets a callback function to receive the file information which are used by the stack.

Prototype

void IP_WEBS_SetFileInfoCallback ( IP_WEBS_pfGetFileInfo pf );

Parameter

Additional information

The function can be used to change the default behavior of the web server. If the file

info callback function is set, the web server calls it to retrieve the file information.

The file information are used to decide how to handle the file and to build the HTML

header. By default (no file info callback function is set), the web server parses every

file with the extension.htm to check if dynamic content is included; all requested files

with the extension .cgi are recognized as virtual files. Beside of that, the web

server sends by default the expiration date of a web site in the HTML header. The

default expiration date (THU, 01 JAN 1995 00:00:00 GMT) is in the past, so that the

requested website will never be cached. This is a reasonable default for web pages

with dynamic content. If the callback function returns 0 for DateExp, the expiration

date will not be included in the header. For static websites, it is possible to add the

optional “Last-Modified” header field. The “Last-Modified” header field is not part of

the header by default. Refer to Structure IP_WEBS_FILE_INFO on page 314 for

detailed information about the structure IP_WEBS_FILE_INFO.

Example

static void _GetFileInfo(const char * sFilename, IP_WEBS_FILE_INFO * pFileInfo){

int v;

// .cgi files are virtual, everything else is not

v = IP_WEBS_CompareFilenameExt(sFilename, ".cgi");

pFileInfo->IsVirtual = v ? 0 : 1;

// .htm files contain dynamic content, everything else is not

v = IP_WEBS_CompareFilenameExt(sFilename, ".htm");

pFileInfo->AllowDynContent = v ? 0 : 1;

// If file is a virtual file or includes dynamic content,

// get current time and date stamp as file time

pFileInfo->DateLastMod = _GetTimeDate();

if (pFileInfo->IsVirtual || pFileInfo->AllowDynContent) {

// Set last-modified and expiration time and date

pFileInfo->DateExp = _GetTimeDate(); // If "Expires" HTTP header field should

// be transmitted, set expiration date.

} else {

pFileInfo->DateExp = 0xEE210000; // Expiration far away (01 Jan 2099)

// if content is static

}

Parameter Description

pf [IN] Pointer to a callback function.

Table 15.11: IP_WEBS_SetFileInfoCallback() parameter list

295

15.11.9 IP_WEBS_AddFileTypeHook()

Description

Registers an element of type WEBS_FILE_TYPE_HOOK to extend or override the list of

file extension to MIME type correlation.

Prototype

void IP_WEBS_AddFileTypeHook ( WEBS_FILE_TYPE_HOOK * pHook,

const char * sExt,

const char * sContent );

Parameter

Additional information

The function can be used to extend or override the basic list of file extension to MIME

type correlations included in the Web server. It might be necessary to extend the this

list in case you want to serve a yet unkown file format. The header sent for this file in

case a client reuqests it will be generated based on this information. Refer to Struc-

ture WEBS_FILE_TYPE_HOOK on page 318 for detailed information about the struc-

ture WEBS_FILE_TYPE_HOOK.

Example

static WEBS_FILE_TYPE_HOOK _FileTypeHook;

int main(void){

// Register *.new files to be treated as binary that will

// be offered to be downloaded by the browser.

IP_WEBS_AddFileTypeHook(&_FileTypeHook, “new“, “application/octet-stream“);

}

Parameter Description

pHook [IN] Pointer to an element of type WEBS_FILE_TYPE_HOOK.

sExt [IN] String containing the extension without leading dot.

sContent [IN] String containing the MIME type associated to the extension.

Table 15.12: IP_WEBS_AddFileTypeHook() parameter list

296 CHAPTER 15 Web server (Add-on)

15.11.10IP_WEBS_ConfigSendVFileHeader()

Description

Configures behavior of automatically sending a header containing a MIME type asso-

ciated to the requested files extension based on an internal list for a requested vir-

tual file.

Prototype

void IP_WEBS_ConfigSendVFileHeader ( U8 OnOff );

Parameter

Additional information

In case you decide not to let the Web server generate a header with the best content

believed to be known you will either have to completely send a header on your own

or sending a header using the function IP_WEBS_SendHeader() on page 298. Send-

ing a header has to be done before sending any other content.

Parameter Description

OnOff [IN] 0: Off, header will not be automatically generated and sent. 1:

On, header will be automatically generated. Default: On.

Table 15.13: IP_WEBS_ConfigSendVFileHeader() parameter list

297

15.11.11IP_WEBS_ConfigSendVFileHookHeader()

Description

Configures behavior of automatically sending a header containing a MIME type asso-

ciated to the requested files extension based on an internal list for a requested file

being served by a registered VFile hook.

Prototype

void IP_WEBS_ConfigSendVFileHookHeader ( U8 OnOff );

Parameter

Additional information

In case you decide not to let the Web server generate a header with the best content

believed to be known you will either have to completely send a header on your own

or sending a header using the function IP_WEBS_SendHeader() on page 298. Send-

ing a header has to be done before sending any other content.

Parameter Description

OnOff [IN] 0: Off, header will not be automatically generated and sent. 1:

On, header will be automatically generated. Default: On.

Table 15.14: IP_WEBS_ConfigSendVFileHookHeader() parameter list

298 CHAPTER 15 Web server (Add-on)

15.11.12IP_WEBS_SendHeader()

Description

Generates and sends a header based on the information passed to this function.

Prototype

void IP_WEBS_SendHeader ( WEBS_OUTPUT * pContext,

const char * sFileName,

const char * sMimeType );

Parameter

Additional information

This function can be used in case automatically generating and sending a header has

been switched off using IP_WEBS_ConfigSendVFileHeader() on page 296 or

IP_WEBS_ConfigSendVFileHookHeader() on page 297. Typically this is the first func-

tion you call from your callback generating content for a virtual file or a VFile hook

registered callback providing content before you send any other data.

Parameter Description

pContext [IN] Pointer to the context used for sending data from your callback

to the client.

sFileName [IN] String containing the file name including extension to be writ-

ten to the header.

sMimeType [IN] String containing the MIME type that is sent back in the header.

Table 15.15: IP_WEBS_SendHeader() parameter list

299

15.11.13IP_WEBS_CompareFileNameExt()

Description

Checks if the given filename has the given extension.

Prototype

char IP_WEBS_CompareFilenameExt( const char * sFilename,

const char * sExt );

Parameter

Return value

0 Match

!= 0 Mismatch

Additional information

The test is case-sensitive, meaning:

IP_WEBS_CompareFilenameExt("Index.html", ".html") ---> Match

IP_WEBS_CompareFilenameExt("Index.htm", ".html") ---> Mismatch

IP_WEBS_CompareFilenameExt("Index.HTML", ".html") ---> Mismatch

IP_WEBS_CompareFilenameExt("Index.html", ".HTML") ---> Mismatch

Parameter Description

sFilename [IN] Name of the file.

sExt [IN] Extension which should be checked.

Table 15.16: IP_WEBS_CompareFilenameExt() parameter list

300 CHAPTER 15 Web server (Add-on)

15.11.14IP_WEBS_GetNumParas()

Description

Returns the number of parameter/value pairs.

Prototype

int IP_WEBS_GetNumParas ( const char * sParameters );

Parameter

Return value

Number of parameters/value pairs.

-1 if the string does not include parameter value pairs.

Additional information

Parameters are separated from values by a ’=’. If a string includes more as one

parameter/value pair, the parameter/value pairs are separated by a ’&’. For example,

if the virtual file Send.cgi gets two parameters, the string should be similar to the

following: Send.cgi?FirstName=Foo&LastName=Bar

sParameter is in this case FirstName=Foo&LastName=Bar. If you call

IP_WEBS_GetNumParas() with this string, the return value will be 2.

Parameter Description

sParameters [IN] Zero-terminated string with parameter/value pairs.

Table 15.17: IP_WEBS_GetNumParas() parameter list

301

15.11.15IP_WEBS_GetParaValue()

Description

Parses a string for valid parameter/value pairs and writes the results in the respec-

tive buffers.

Prototype

int IP_WEBS_GetParaValue( const char * sBuffer,

int ParaNum,

char * sPara,

int ParaLen,

char * sValue,

int ValueLen );

Parameter

Return value

0: O.K.

>0: Error

Additional information

A valid string is in the following format:

If the parameter value string is FirstName=John&LastName=Doo and parameter 0

should be copied, sPara will be FirstName and sValue John. If parameter 1 should

be copied, sPara will be LastName and sValue Doo.

Parameter Description

sBuffer [IN] Zero-terminated parameter/value string that should be parsed.

ParaNum [IN] Zero-based index of the parameter/value pairs.

sPara [Out] Buffer to store the the parameter name. (Optional, can be

NULL.)

ParaLen [IN] Size of the buffer to store the parameter. (0 if sPara is NULL.)

sValue [Out] Buffer to store the the value. (Optional, can be NULL.)

ValueLen [IN] Size of the buffer to store the value. (0 if sValue is NULL.)

Table 15.18: IP_WEBS_GetParaValue() parameter list

302 CHAPTER 15 Web server (Add-on)

15.11.16IP_WEBS_GetParaValuePtr()

Description

Parses a string for valid parameter/value pairs and returns a pointer to the requested

paramater and the length of the paramater string without termination.

Prototype

int IP_WEBS_GetParaValuePtr( const char * sBuffer,

int ParaNum,

const char ** ppPara,

int * pParaLen,

const char ** ppValue,

int * pValueLen );

Parameter

Return value

0: O.K.

>0: Error

Additional information

A valid string is in the following format:

This function can be used in case you simply want to check or use the paramaters

passed by the client without modyfing them. Depending on your application this

might save you a lot of stack that otherwise would have to be wasted for copying the

same data that is already perfectly present to another location. This saves execution

time as of course the data will not have to be copied.

Example

/* Excerpt from OS_IP_Webserver.c */

/*********************************************************************

* _callback_CGI_Send

static void _callback_CGI_Send(WEBS_OUTPUT * pOutput, const char * sParameters) {

int r;

const char * pFirstName;

int FirstNameLen;

const char * pLastName;

int LastNameLen;

IP_WEBS_SendString(pOutput, "<HTML><HEAD><TITLE>Virtual file example</TITLE></

HEAD>");

IP_WEBS_SendString(pOutput, "<style type=\"text/css\"> \

H1, H2, H3, H4 { color: white; font-family: Helvetica; } \

Parameter Description

sBuffer [IN] Zero-terminated parameter/value string that should be parsed.

ParaNum [IN] Zero-based index of the parameter/value pairs.

ppPara [Out] Pointer to the pointer locating the start of the requested para-

mater name. (Optional, can be NULL.)

pParaLen [OUT] Pointer to a buffer to store the length of the parameter name

without termination. (Optional, can be NULL.)

ppValue [Out] Pointer to the pointer locating the start of the requested

parameter value. (Optional, can be NULL.)

pValueLen [OUT] Pointer to a buffer to store the length of the parameter value

without termination. (Optional, can be NULL.)

Table 15.19: IP_WEBS_GetParaValuePtr() parameter list

303

PRE { color: white; margin-left: 2%; ; font-size=150%} \

BODY{padding:0px; margin:0px; text-align:center; font-family:Verdana, Helvetica,

sans-serif; background:#6699CC url(bg.png) repeat-x; font-size:11px; color:white } \

A:link { font-weight:bold; color:white; text-decoration:none; } \

A:visited { font-weight:bold; color:silver; text-decoration:none; } \

A:focus { font-weight:bold; color:white; text-decoration:underline; } \

A:hover { font-weight:bold; color:silver; text-decoration:none; } \

A:active { font-weight:bold; color:white; text-decoration:underline; }\

</style>");

IP_WEBS_SendString(pOutput, "<BODY><CENTER><HR><H2>Virtual file example</H2><HR></

CENTER><BR><BR><BR>");

r = IP_WEBS_GetParaValuePtr(sParameters, 0, NULL, 0, &pFirstName, &FirstNameLen);

r |= IP_WEBS_GetParaValuePtr(sParameters, 1, NULL, 0, &pLastName, &LastNameLen);

if (r == 0) {

IP_WEBS_SendString(pOutput, "First name: ");

IP_WEBS_SendMem(pOutput, pFirstName, FirstNameLen);

IP_WEBS_SendString(pOutput, "<BR>Last name: ");

IP_WEBS_SendMem(pOutput, pLastName, LastNameLen);

} else {

IP_WEBS_SendString(pOutput, "<BR>Error!");

}

IP_WEBS_SendString(pOutput, "<BR><BR><BR>");

IP_WEBS_SendString(pOutput, "<HR><CENTER><A HREF=\"index.htm\">Back to main</A></

CENTER><IMG SRC=\"logo.gif\" ALT=\"Segger logo\">   SEGGER Microcontroller

GmbH & Co. KG   <A HREF=\"http://www.segger.com\">www.segger.com</A></

BODY></HTML>");

}

304 CHAPTER 15 Web server (Add-on)

15.11.17IP_WEBS_DecodeAndCopyStr()

Description

Checks if a string includes url encoded characters, decodes the characters and copies

them into destination buffer.

Prototype

void IP_WEBS_DecodeAndCopyStr ( char * pDest,

int DestLen,

const char * pSrc,

int SrcLen );

Parameter

Additional information

Destination string is 0-terminated. Source and destination buffer can be identical.

Parameter Description

pDest [OUT] Buffer to store the decoded string.

DestLen [IN] Size of the destination buffer.

pSrc [IN] Source string that should be decoded.

SrcLen [IN] Size of the source string.

Table 15.20: IP_WEBS_DecodeAndCopyStr() parameter list

pSrc SrcLen pDest DestLen

"FirstName=J%F6rg" 16 "FirstName=Jörg\0" 15

"FirstName=John" 14 "FirstName=John\0" 15

Table 15.21: Example

305

15.11.18IP_WEBS_DecodeString()

Description

Checks if a string includes url encoded characters, decodes the characters.

Prototype

int IP_WEBS_DecodeString( const char * s );

Parameter

Return value

0 String does not include url encoded characters. No change.

>0 Length of the decoded string, including the terminating null character.

Parameter Description

s[IN/OUT] Zero-terminated string that should be decoded.

Table 15.22: IP_WEBS_DecodeString() parameter list

306 CHAPTER 15 Web server (Add-on)

15.11.19IP_WEBS_AddVFileHook()

Description

Registers a function table containing callbacks to check and serve simple virtual file

content that is not further processed by the Web server.

Prototype

void IP_WEBS_AddVFileHook ( WEBS_VFILE_HOOK * pHook,

WEBS_VFILE_APPLICATION * pVFileApp );

Parameter

Additional information

The function can be used to serve simple dynamically generated content for a

requested file name that is simply sent back as generated by the application and is

not further processed by the Web server. Refer to Structure WEBS_VFILE_HOOK on

page 316 for detailed information about the structure WEBS_VFILE_HOOK. Refer to

Structure WEBS_VFILE_APPLICATION on page 315 for detailed information about the

structure WEBS_VFILE_APPLICATION.

Example

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* _UPnP_GenerateSend_upnp_xml

* Function description

* Send the content for the requested file using the callback provided.

* Parameters

* pContextIn - Send context of the connection processed for

* forwarding it to the callback used for output.

* pf - Function pointer to the callback that has to be

* for sending the content of the VFile.

* pContextOut - Out context of the connection processed.

* pData - Pointer to the data that will be sent

* NumBytes - Number of bytes to send from pData. If NumBytes

* is passed as 0 the send function will run a strlen()

* on pData expecting a string.

* Notes

* (1) The data does not need to be sent in one call of the callback

* routine. The data can be sent in blocks of data and will be

* flushed out automatically at least once returning from this

* routine.

static void _UPnP_GenerateSend_upnp_xml(void * pContextIn, void (*pf) (void * pCon-

textOut, const char * pData, unsigned NumBytes)) {

char ac[128];

pf(pContextIn, "<?xml version=\"1.0\"?>\r\n"

"<root xmlns=\"urn:schemas-upnp-org:device-1-0\">\r\n"

"<specVersion>\r\n"

"<major>1</major>\r\n"

"<minor>0</minor>\r\n"

"</specVersion>\r\n", 0);

}

Parameter Description

pHook [IN] Pointer to an element of type WEBS_VFILE_HOOK.

pVFileApp [IN] Pointer to an element of type WEBS_VFILE_APPLICATION.

Table 15.23: IP_WEBS_AddVFileHook() parameter list

307

/* Excerpt from OS_IP_WebserverUPnP.c */

// UPnP webserver VFile hook

static WEBS_VFILE_HOOK _UPnP_VFileHook;

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* _UPnP_CheckVFile

* Function description

* Check if we have content that we can deliver for the requested

* file using the VFile hook system.

* Parameters

* sFileName - Name of the file that is requested

* pIndex - Pointer to a variable that has to be filled with

* the index of the entry found in case of using a

* filename<=>content list.

* Alternative all comparisons can be done using the

* filename. In this case the index is meaningless

* and does not need to be returned by this routine.

* Return value

* 0 - We do not have content to send for this filename,

* fall back to the typical methods for retrieving

* a file from the web server.

* 1 - We have content that can be sent using the VFile

* hook system.

static int _UPnP_CheckVFile(const char * sFileName, unsigned * pIndex) {

unsigned i;

// Generated VFiles

if (strcmp(sFileName, "/upnp.xml") == 0) {

return 1;

}

// Static VFiles

for (i = 0; i < SEGGER_COUNTOF(_VFileList); i++) {

if (strcmp(sFileName, _VFileList[i].sFileName) == 0) {

*pIndex = i;

return 1;

}

return 0;

}

/*********************************************************************

* _UPnP_SendVFile

* Function description

* Send the content for the requested file using the callback provided.

* Parameters

* pContextIn - Send context of the connection processed for

* forwarding it to the callback used for output.

* Index - Index of the entry of a filename<=>content list

* if used. Alternative all comparisons can be done

* using the filename. In this case the index is

* meaningless. If using a filename<=>content list

* this is faster than searching again.

308 CHAPTER 15 Web server (Add-on)

* sFileName - Name of the file that is requested. In case of

* working with the Index this is meaningless.

* pf - Function pointer to the callback that has to be

* for sending the content of the VFile.

* pContextOut - Out context of the connection processed.

* pData - Pointer to the data that will be sent

* NumBytes - Number of bytes to send from pData. If NumBytes

* is passed as 0 the send function will run a strlen()

* on pData expecting a string.

static void _UPnP_SendVFile(void * pContextIn, unsigned Index, const char * sFile-

Name, void (*pf) (void * pContextOut, const char * pData, unsigned NumBytes)) {

(void)sFileName;

// Generated VFiles

if (strcmp(sFileName, "/upnp.xml") == 0) {

_UPnP_GenerateSend_upnp_xml(pContextIn, pf);

return;

}

// Static VFiles

pf(pContextIn, _VFileList[Index].pData, _VFileList[Index].NumBytes);

}

static WEBS_VFILE_APPLICATION _UPnP_VFileAPI = {

_UPnP_CheckVFile,

_UPnP_SendVFile

};

/* Excerpt from OS_IP_WebserverUPnP.c */

/*********************************************************************

* MainTask

void MainTask(void);

void MainTask(void) {

// Activate UPnP with VFile hook for needed XML files

IP_WEBS_AddVFileHook(&_UPnP_VFileHook, &_UPnP_VFileAPI);

}

309

15.11.20IP_UTIL_BASE64_Decode()

Description

Performs BASE-64 decoding according to RFC3548.

Prototype

int IP_UTIL_BASE64_Decode( const U8 * pSrc,

int SrcLen,

U8 * pDest,

int * pDestLen );

Parameter

Return value

< 0 Error

> 0 Number of source bytes encoded, further call required

0 All bytes encoded

Additional information

For more information, refer to http://tools.ietf.org/html/rfc3548.

Parameter Description

pSrc [IN] Pointer to data to encode.

SrcLen Number of bytes to encode.

pDest [IN] Pointer to the destination buffer.

pDestLen

[IN] Pointer to the destination buffer size.

[OUT] Pointer to the number of bytes used in the destination

buffer.

Table 15.24: IP_UTIL_BASE64_Decode() parameter list

310 CHAPTER 15 Web server (Add-on)

15.11.21IP_UTIL_BASE64_Encode()

Description

Performs BASE-64 encoding according to RFC3548.

Prototype

int IP_UTIL_BASE64_Encode( const U8 * pSrc,

int SrcLen,

U8 * pDest,

int * pDestLen );

Parameter

Return value

< 0 Error

> 0 Number of source bytes encoded, further call required

0 All bytes encoded

Additional information

For more information, refer to http://tools.ietf.org/html/rfc3548.

Parameter Description

pSrc [IN] Pointer to data to encode.

SrcLen Number of bytes to encode.

pDest [IN] Pointer to the destination buffer.

pDestLen

[IN] Pointer to the destination buffer size.

[OUT] Pointer to the number of bytes used in the destination

buffer.

Table 15.25: IP_UTIL_BASE64_Encode() parameter list

311

15.12 Web server data structures

15.12.1 Structure WEBS_CGI

Description

Used to store the CGI command names and the pointer to the proper callback func-

tions.

Prototype

typedef struct {

const char * sName;

void (*pf)(WEBS_OUTPUT * pOutput, const char * sParameters);

} WEBS_CGI;

Additional information

Refer to Common Gateway Interface (CGI) on page 270 for detailed information

about the use of this structure.

Member Description

sName Name of the CGI command.

pf Pointer to a callback function.

Table 15.26: Structure WEBS_CGI member list

312 CHAPTER 15 Web server (Add-on)

15.12.2 Structure WEBS_ACCESS_CONTROL

Description

Used to store information for the HTTP Basic Authentication scheme.

Prototype

typedef struct {

const char * sPath;

const char * sRealm;

const char * sUserPass;

} WEBS_ACCESS_CONTROL;

Additional information

If sRealm is initialized with NULL, sUserPass is not interpreted by the web server.

Refer to Authentication on page 274 for detailed information about the HTTP Basic

Authentication scheme.

Member Description

sPath A string which defines the path of the resources.

sRealm A string which defines the realm which requires authentication.

Optional, can be NULL.

sUserPass A string containing the user name/password combination.

Optional, can be NULL.

Table 15.27: Structure WEBS_ACCESS_CONTROL member list

313

15.12.3 Structure WEBS_APPLICATION

Description

Used to store application-specific parameters.

Prototype

typedef struct {

const WEBS_CGI * paCGI;

WEBS_ACCESS_CONTROL * paAccess;

void (*pfHandleParameter)( WEBS_OUTPUT * pOutput,

const char sPara,

const char * sValue );

} WEBS_APPLICATION;

Member Description

paCGI Pointer to an array of structures of type WEBS_CGI.

paAccess Pointer to an array of structures of type

WEBS_ACCESS_CONTROL.

pfHandleParameter Pointer to an array of structures of type WEBS_CGI.

Table 15.28: Structure WEBS_APPLICATION member list

314 CHAPTER 15 Web server (Add-on)

15.12.4 Structure IP_WEBS_FILE_INFO

Description

Used to store application-specific parameters.

Prototype

typedef struct {

U32 DateLastMod; // Used for "Last modified" header field

U32 DateExp; // Used for "Expires" header field

U8 IsVirtual;

U8 AllowDynContent;

} IP_WEBS_FILE_INFO;

Member Description

DateLastModified The date when the file has been last modified.

DateExp The date of the expiration of the valiity.

IsVirtual Flag to indicate if a file is virtual or not. Valid values are 0 for

non-virtual, 1 for virtual files.

AllowDynContent

Flag to indicate if a file should be parsed for dynamic content

or not. 0 means that the file should not be parsed for dynamic

content, 1 means that the file should be parsed for dynamic

content.

Table 15.29: Structure IP_WEBS_FILE_INFO member list

315

15.12.5 Structure WEBS_VFILE_APPLICATION

Description

Used to check if the application can provide content for a simple VFile.

Prototype

typedef struct WEBS_VFILE_APPLICATION {

int (*pfCheckVFile)(const char * sFileName, unsigned * pIndex);

void (*pfSendVFile) (void * pContextIn,

unsigned Index,

const char * sFileName,

void (*pf) (void * pContextOut,

const char * pData,

unsigned NumBytes));

} WEBS_VFILE_APPLICATION;

Member Description

pfCheckVFile Pointer to a callback for checking if content for a requested file

name can be served.

pfSendVFile

Pointer to a callback for actually sending the content for the

requested file name using the provided callback pf. In case

NumBytes is passed with ’0’ the callback expects to find a

string and will automatically run strlen() to find out the length

of the string internally. In case NumBytes is not passed ’>0’

only NumBytes from the start of pData will be sent.

Table 15.30: Structure WEBS_VFILE_APPLICATION member list

316 CHAPTER 15 Web server (Add-on)

15.12.6 Structure WEBS_VFILE_HOOK

Description

Used to send application generated content from the application upon request of a

specific file name.

Prototype

typedef struct WEBS_VFILE_HOOK {

struct WEBS_VFILE_HOOK * pNext;

WEBS_VFILE_APPLICATION * pVFileApp;

} WEBS_VFILE_HOOK;

Additional information

Refer to Structure WEBS_VFILE_HOOK on page 316 for detailed information about

the structure WEBS_VFILE_HOOK. Refer to Structure WEBS_VFILE_APPLICATION on

page 315 for detailed information about the structure WEBS_VFILE_APPLICATION.

Member Description

pNext Pointer to the previously registered element of

WEBS_VFILE_HOOK.

pVFileApp Pointer to an element of type WEBS_VFILE_APPLICATION.

Table 15.31: Structure WEBS_VFILE_HOOK member list

317

15.12.7 Structure WEBS_FILE_TYPE

Description

Used to extend or overwrite the file extension to MIME type correlation.

Prototype

typedef struct WEBS_FILE_TYPE {

const char *sExt;

const char *sContent;

} WEBS_FILE_TYPE;

Member Description

sExt String containing the extension without leading dot.

sContent String containing the MIME type associated to the extension.

Table 15.32: Structure WEBS_FILE_TYPE member list

318 CHAPTER 15 Web server (Add-on)

15.12.8 Structure WEBS_FILE_TYPE_HOOK

Description

Used to extend or overwrite the file extension to MIME type correlation.

Prototype

typedef struct WEBS_FILE_TYPE_HOOK {

struct WEBS_FILE_TYPE_HOOK * pNext;

WEBS_FILE_TYPE FileType;

} WEBS_FILE_TYPE_HOOK;

Additional information

Refer to Structure WEBS_FILE_TYPE_HOOK on page 318 for detailed information

about the structure WEBS_FILE_TYPE_HOOK. Refer to Structure WEBS_FILE_TYPE on

page 317 for detailed information about the structure WEBS_FILE_TYPE.

Member Description

pNext Pointer to the previously registered element of

WEBS_FILE_TYPE_HOOK.

FileType Element of Structure WEBS_FILE_TYPE.

Table 15.33: Structure WEBS_VFILE_HOOK member list

319

15.13 Resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the web server presented in the tables below have

been measured on an ARM7 and a Cortex-M3 system. Details about the further con-

figuration can be found in the sections of the specific example.

Configuration used

#define WEBS_IN_BUFFER_SIZE 256

#define WEBS_OUT_BUFFER_SIZE 512

#define WEBS_TEMP_BUFFER_SIZE 256

#define WEBS_PARA_BUFFER_SIZE 256

#define WEBS_ERR_BUFFER_SIZE 128

#define WEBS_AUTH_BUFFER_SIZE 32

#define WEBS_FILENAME_BUFFER_SIZE 32

15.13.1 ROM usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

15.13.2 ROM usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

15.13.3 RAM usage:

Almost all of the RAM used by the web server is taken from task stacks. The amount

of RAM required for every child task depends on the configuration of your server. The

table below shows typical RAM requirements for your task stacks.

Note: The web server requires at least 1 child task.

The approximately RAM usage for the web server can be calculated as follows:

RAM usage = 0.1 Kbytes + ParentTask + (NumberOfChildTasks * 1.8 Kbytes)

Example: Web server accepting only 1 connection

RAM usage = 0.1 Kbytes + 500 +(1 * 1.8 Kbytes)

RAM usage = 2.4 Kbytes

Example: Web server accepting up to 3 connections in parallel

RAM usage = 0.1 Kbytes + 500 + (3 * 1.8 Kbytes)

RAM usage = 6.0 Kbytes

Addon ROM

embOS/IP Web server approximately 5.9Kbyte

Table 15.34: Web server ROM usage ARM7

Addon ROM

embOS/IP Web server approximately 5.4Kbyte

Table 15.35: Web server ROM usage Cortex-M3

Task Description RAM

ParentTask Listens for incoming connections. approximately 500 bytes

ChildTask Handles a request. approximately 1800 bytes

Table 15.36: Web server RAM usage

320 CHAPTER 15 Web server (Add-on)

321

Chapter 16

SMTP client (Add-on)

The embOS/IP SMTP client is an optional extension to embOS/IP. The SMTP client can

be used with embOS/IP or with a different TCP/IP stack. All functions that are

required to add the SMTP client task to your application are described in this chapter.

322 CHAPTER 16 SMTP client (Add-on)

16.1 embOS/IP SMTP client

The embOS/IP SMTP client is an optional extension which can be seamlessly inte-

grated into your TCP/IP application. It combines a maximum of performance with a

small memory footprint. The SMTP client allows an embedded system to send emails

with dynamically generated content. The RAM usage of the SMTP client module has

been kept to a minimum by smart buffer handling.

The SMTP client implements the relevant parts of the following Request For Com-

ments (RFC).

The following table shows the contents of the embOS/IP SMTP client root directory:

RFC# Description

[RFC 821] Simple Mail Transfer Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc821.txt

[RFC 974] Mail routing and the domain system

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc974.txt

[RFC 2554] SMTP Service Extension for Authentication

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc2554.txt

[RFC 5321] Simple Mail Transfer Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc5321.txt

Directory Content

Application\ Contains the example application to run

the SMTP client with embOS/IP.

Config

Contains the SMTP client configuration file.

Refer to Configuration on page 327 for

detailed information.

Inc Contains the required include files.

IP Contains the SMTP client sources,

IP_SMTPC.c and IP_SMTPC.h.

Windows\SMTPC\

Contains the source, the project files and

an executable to run embOS/IP SMTP cli-

ent on a Microsoft Windows host.

Supplied directory structure of embOS/IPSMTP client package

323

16.2 Feature list

• Low memory footprint.

• Independent of the TCP/IP stack: any stack with sockets can be used.

• Example applications included.

• Project for executable on PC for Microsoft Visual Studio included.

324 CHAPTER 16 SMTP client (Add-on)

16.3 Requirements

TCP/IP stack

The embOS/IP SMTP client requires a TCP/IP stack. It is optimized for embOS/IP, but

any RFC-compliant TCP/IP stack can be used. The shipment includes a Win32 simula-

tion, which uses the standard Winsock API and an implementation which uses the

socket API of embOS/IP.

Multi tasking

The SMTP client needs to run as a separate thread. Therefore, a multi tasking system

is required to use the embOS/IP SMTP client.

325

16.4 SMTP backgrounds

The Simple Mail Transfer Protocol is a text based communication protocol for elec-

tronic mail transmission across IP networks.

Using SMTP, an embOS/IP application can transfer mail to an SMTP servers on the

same network or to SMTP servers in other networks via a relay or gateway server

accessible to both networks. When the embOS/IP SMTP client has a message to

transmit, it establishes a TCP connection to an SMTP server and transmits after the

handshaking the message content.

The handshaking mechanism includes normally an authentication process. The RFC’s

define the following four different authentication schemes:

•PLAIN

•LOGIN

• CRAM-MD5

•NTLM

In the current version, the embOS/IP SMTP client supports only PLAIN authentica-

tion. The following listing shows a typical SMTP session:

S: 220 srv.sample.com ESMTP

C: HELO

S: 250 srv.sample.com

C: AUTH LOGIN

S: 334 VXNlcm5hbWU6

C: c3BzZXk29IulbkY29tZcZXIbtZ

S: 334 UGFzc3dvcmQ6

C: UlblhFz7ZlblsZlZQ==

S: 235 go ahead

C: Mail from:<user0@sample.com>

S: 250 ok

C: Rcpt to:<user1@sample.com>

S: 250 ok

C: Rcpt to:<user2@sample.com>

S: 250 ok

C: Rcpt to:<user3@sample.com>

S: 250 ok

C: DATA

S: 354 go ahead

C: Message-ID: <1000.2234@sample.com>

C: From: "User0" <User0@sample.com>

C: TO: "User1" <User1@sample.com>

C: CC: "User2" <User2@sample.com>, "User3" <User3@sample.com>

Application layer

Transport layer

Network layer

Link layer

SMTP

TCP

Ethernet (IEEE 802.3), ...

326 CHAPTER 16 SMTP client (Add-on)

C: Subject: Testmail

C: Date: 1 Jan 2008 00:00 +0100

C: This is a test!

C: .

S: 250 ok 1231221612 qp 3364

C: quit

S: 221 srv.sample.com

327

16.5 Configuration

The embOS/IP SMTP client can be used without changing any of the compile time

flags. All compile time configuration flags are preconfigured with valid values, which

match the requirements of most applications.

The following types of configuration macros exist:

Binary switches "B"

Switches can have a value of either 0 or 1, for deactivated and activated respectively.

Actually, anything other than 0 works, but 1 makes it easier to read a configuration

file. These switches can enable or disable a certain functionality or behavior.

Switches are the simplest form of configuration macros.

Numerical values "N"

Numerical values are used somewhere in the source code in place of a numerical con-

stant. A typical example is the configuration of the sector size of a storage medium.

Alias "A"

A macro which operates like a simple text substitute. An example would be the define

U8, which the preprocessor would replace with unsigned char.

Function replacements "F"

Macros can basically be treated like regular functions although certain limitations

apply, as a macro is still put into the source code as simple text replacement. Func-

tion replacements are mainly used to add specific functionality to a module which is

highly hardware-dependent. This type of macro is always declared using brackets

(and optional parameters).

16.5.1 Compile time configuration switches

Type Symbolic name Default Description

FSMTPC_WARN --

Defines a function to output

warnings. In debug configura-

tions (DEBUG == 1) SMTPC_WARN

maps to

IP_Warnf_Application().

FSMTPC_LOG --

Defines a function to output log-

ging messages. In debug config-

urations (DEBUG == 1)

SMTPC_LOG maps to

IP_Logf_Application().

NSMTPC_SERVER_PORT 25 Defines the port where the SMTP

server is listening.

NSMTPC_IN_BUFFER_SIZE 256

Defines the size of the input

buffer. The input buffer is used to

store the SMTP replies of the

SMTP server.

NSMTPC_AUTH_USER_BUFFER_SIZE 48

Defines the size of the buffer

used for the Base-64 encoded

user name.

NSMTPC_AUTH_PASS_BUFFER_SIZE 48

Defines the size of the buffer

used for the Base-64 encoded

password.

328 CHAPTER 16 SMTP client (Add-on)

16.6 API functions

Function Description

SMTP client functio ns

IP_SMTPC_Send() Sends an email to a mail transfer agent.

Table 16.1: embOS/IP SMTP client interface function overview

329

16.6.1 IP_SMTPC_Send()

Description

Sends an email to one or multiple recipients.

Prototype

int IP_SMTPC_Send( const IP_SMTPC_API * pIP_API,

IP_SMTPC_MAIL_ADDR * paMailAddr,

int NumMailAddr,

IP_SMTPC_MESSAGE * pMessage,

const IP_SMTPC_MTA * pMTA,

const IP_SMTPC_APPLICATION * pApplication );

Parameter

Return value

0 OK.

1 Error.

Parameter Description

pIP_API

[IN] Pointer to an IP_STMPC_API structure. Refer to Structure

IP_SMTPC_API on page 331 for detailed information about the ele-

ments of the IP_SMTPC_API structure.

paMailAddr

[IN] Pointer to an array of IP_SMTPC_MAIL_ADDR structures. Refer to

Structure IP_SMTPC_MAIL_ADDR on page 334 for detailed informa-

tion about the elements of the IP_SMTPC_MAIL_ADDR structure. The

first element of the array has to be filled with the data of the sender

(FROM). The order of the following data sets for recipients (TO),

carbon copies (CC) and blind carbon copies (BCC) is not relevant.

NumMailAddr [IN] Number of email addresses.

pMessage

[IN] Pointer to an array of IP_SMTPC_MESSAGE structures. Refer to

Structure IP_SMTPC_MESSAGE on page 336 for detailed information

about the elements of the IP_SMTPC_MESSAGE structure.

pMTA

[IN] Pointer to an array of IP_SMTPC_MTA structures. Refer to Struc-

ture IP_SMTPC_MTA on page 337 for detailed information about the

elements of the IP_SMTPC_MTA structure.

pApplication

[IN] Pointer to an array of IP_SMTPC_APPLICATION structures. Refer

to Structure IP_SMTPC_APPLICATION on page 333 for detailed

information about the elements of the IP_SMTPC_APPLICATION

structure.

Table 16.2: IP_SMTPC_Send() parameter list

330 CHAPTER 16 SMTP client (Add-on)

16.7 SMTP client data structures

Function Description

IP_SMTPC_API Structure with pointers to the required

socket interface functions.

IP_SMTPC_APPLICATION Structure with application related elements.

IP_SMTPC_MAIL_ADDR Structure to store the mail addresses.

IP_SMTPC_MESSAGE Structure defining the message format.

IP_SMTPC_MTA Structure to store the login information for

the mail transfer agent.

Table 16.3: embOS/IP SMTP client interface function overview

331

16.7.1 Structure IP_SMTPC_API

Description

Structure with pointers to the required socket interface functions.

Prototype

typedef struct {

SMTPC_SOCKET (*pfConnect) (char * SrvAddr);

void (*pfDisconnect) (SMTPC_SOCKET Socket);

int (*pfSend) (const char * pData,

int Len,

SMTPC_SOCKET Socket);

int (*pfReceive) (char * pData,

int Len,

SMTPC_SOCKET Socket);

} IP_SMTPC_API;

Example

/*********************************************************************

* _Connect

* Function description

* Creates a socket and opens a TCP connection to the mail host.

static SMTPC_SOCKET _Connect(char * SrvAddr) {

long IP;

long Sock;

struct hostent * pHostEntry;

struct sockaddr_in sin;

int r;

// Convert host into mail host

pHostEntry = gethostbyname(SrvAddr);

if (pHostEntry == NULL) {

SMTPC_LOG(("gethostbyname failed: %s\r\n", SrvAddr));

return NULL;

}

IP = *(unsigned*)(*pHostEntry->h_addr_list);

// Create socket and connect to mail server

Sock = socket(AF_INET, SOCK_STREAM, 0);

if(Sock == -1) {

SMTPC_LOG(("Could not create socket!"));

return NULL;

}

IP_MEMSET(&sin, 0, sizeof(sin));

sin.sin_family = AF_INET;

sin.sin_port = htons(SERVER_PORT);

sin.sin_addr.s_addr = IP;

r = connect(Sock, (struct sockaddr*)&sin, sizeof(sin));

if(r == SOCKET_ERROR) {

Member Description

pfConnect Pointer to the function (for example, connect()).

pfDisconnect Pointer to the disconnect function (for example, closesocket()).

pfSend Pointer to a callback function (for example, send()).

pfDisconnect Pointer to a callback function (for example, recv()).

Table 16.4: Structure IP_SMTPC_API member list

332 CHAPTER 16 SMTP client (Add-on)

SMTPC_LOG(("\nSocket error :"));

return NULL;

}

SMTPC_LOG(("APP: Connected.\r\n"));

return (SMTPC_SOCKET)Sock;

}

/*********************************************************************

* _Disconnect

* Function description

* Closes a socket.

static void _Disconnect(SMTPC_SOCKET Socket) {

closesocket((long)Socket);

}

/*********************************************************************

* _Send

* Function description

* Sends data via socket interface.

static int _Send(const char * buf, int len, void * pConnectionInfo) {

return send((long)pConnectionInfo, buf, len, 0);

}

/*********************************************************************

* _Recv

* Function description

* Receives data via socket interface.

static int _Recv(char * buf, int len, void * pConnectionInfo) {

return recv((long)pConnectionInfo, buf, len, 0);

}

static const IP_SMTPC_API _IP_Api = {

_Connect,

_Disconnect,

_Send,

_Recv

};

333

16.7.2 Structure IP_SMTPC_APPLICATION

Description

Structure with pointers to application related functions.

Prototype

typedef struct {

U32 (*pfGetTimeDate) (void);

int (*pfCallback)(int Stat, void *p);

const char * sDomain; // email domain

} IP_SMTPC_APPLICATION;

Example

*********************************************************************

* _GetTimeDate

static U32 _GetTimeDate(void) {

U32 r;

U16 Sec, Min, Hour;

U16 Day, Month, Year;

Sec = 0; // 0 based. Valid range: 0..59

Min = 0; // 0 based. Valid range: 0..59

Hour = 0; // 0 based. Valid range: 0..23

Day = 1; // 1 based. Means that 1 is 1.

// Valid range is 1..31 (depending on month)

Month = 1; // 1 based. Means that January is 1. Valid range is 1..12.

Year = 28; // 1980 based. Means that 2008 would be 28.

r = Sec / 2 + (Min << 5) + (Hour << 11);

r |= (U32)(Day + (Month << 5) + (Year << 9)) << 16;

return r;

}

*********************************************************************

* _Application

static const SMTPC_APPLICATION _Application = {

_GetTimeDate,

NULL,

"sample.com" // Your domain.

};

Member Description

pfGetTimeDate Pointer to the function which returns the current system time. Used

to set the correct date and time of the email.

pfCallback Pointer to status callback function. Can be NULL.

sDomain

Domain name. For example, sample.com. According to RFC 821 the

maximum total length of a domain name or number is 64 charac-

ters.

Table 16.5: Structure IP_SMTPC_APPLICATION member list

334 CHAPTER 16 SMTP client (Add-on)

16.7.3 Structure IP_SMTPC_MAIL_ADDR

Description

Structure to store an email address.

Prototype

typedef struct {

const char * sName;

const char * sAddr;

int Type;

} IP_SMTPC_MAIL_ADDR;

Valid values for parameter Type

Additional information

The structure is used to store the data sets of the sender and all recipients.

IP_SMTPC_Send() gets a pointer to an array of IP_SMTPC_MAIL_ADDR structures as

parameter. The first element of these array has to be filled with the data of the

sender (FROM). The order of the following data sets for Recipients (TO), Carbon Cop-

ies (CC) and Blind Carbon Copies (BCC) is not relevant. For detailed information

about IP_SMTPC_Send() refer to IP_SMTPC_Send() on page 329.

Example

/*********************************************************************

* Mailer

static void _Mailer(void) {

SMTPC_MAIL_ADDR MailAddr[4];

SMTPC_MTA Mta;

SMTPC_MESSAGE Message;

IP_MEMSET(&MailAddr, 0, sizeof(MailAddr));

// Sender

MailAddr[0].sName = 0; // for example, "Your name";

MailAddr[0].sAddr = 0; // for example, "user@foobar.com";

MailAddr[0].Type = SMTPC_REC_TYPE_FROM;

// Recipient(s)

MailAddr[1].sName = 0; // "Recipient";

MailAddr[1].sAddr = 0; // "recipient@foobar.com";

MailAddr[1].Type = SMTPC_REC_TYPE_TO;

Member Description

sName Name of the recipient (for example, “Foo Bar”). Can be NULL.

sAddr email address of the recipient (for example, “foo@bar.com”).

Type Type of the email address.

Table 16.6: Structure IP_SMTPC_MAIL_ADDR member list

Value Description

SMTPC_REC_TYPE_FROM email address of the sender (FROM).

SMTPC_REC_TYPE_TO email address of the recipient (TO).

SMTPC_REC_TYPE_CC email address of a recipient which should

get a carbon copy (CC) of the email.

SMTPC_REC_TYPE_BC email address of a recipient which should

get a blind carbon copy (BCC) of the email.

335

MailAddr[2].sName = 0; // "CC Recp 1";

MailAddr[2].sAddr = 0; // "cc1@foobar.com";

MailAddr[2].Type = SMTPC_REC_TYPE_CC;

MailAddr[3].sName = 0; // "BCC Recp 1"

MailAddr[3].sAddr = 0; // "bcc1@foobar.com";;

MailAddr[3].Type = SMTPC_REC_TYPE_BCC;

// Message

Message.sSubject = "SMTP message sent via embOS/IP SMTP client";

Message.sBody = "embOS/IP SMTP client - www.segger.com";

// Fill mail transfer agent structure

Mta.sServer = 0; // for example, "mail.foobar.com";

Mta.sUser = 0; // for example, "user@foobar.com";

Mta.sPass = 0; // for example, "password";

// Check if sample is configured!

if(Mta.sServer == 0) {

SMTPC_WARN(("You have to enter valid SMTP server, sender and recipi-

ent(s).\r\n"));

while(1);

}

// Wait until link is up. This can take 2-3 seconds if PHY has been reset.

while (IP_IFaceIsReady() == 0) {

OS_Delay(100);

}

SMTPC_Send(&_IP_Api, &MailAddr[0], 4, &Message, &Mta, &_Application);

while(1);

}

336 CHAPTER 16 SMTP client (Add-on)

16.7.4 Structure IP_SMTPC_MESSAGE

Description

Structure to store the subject and the text of the email.

Prototype

typedef struct {

const char * sSubject;

const char * sBody;

int MessageSize;

} IP_SMTPC_MESSAGE;

Member Description

sSubject Pointer to the string used as subject of the email.

sBody Pointer to the string used as message of the email.

MessageSize Size of the message.

Table 16.7: Structure IP_SMTPC_MESSAGE member list

337

16.7.5 Structure IP_SMTPC_MTA

Description

Structure to store the server address and the login information.

Prototype

typedef struct {

const char * sServer;

const char * sUser;

const char * sPass;

} IP_SMTPC_MTA;

Additional information

The parameters sUser and sPass have to be NULL if no authentication is used by the

server. If sUser is set in the application code, the client tries to use authentication.

This means that the client sends the AUTH LOGIN command to the server. If the

server does not support authentication, he will return an error code and the client

closes the session.

Member Description

sServer Server address (for example, “mail.foobar.com”).

sUser Account user name (for example, “foo@bar.com”). Can be NULL.

sPass Account password (for example, “password”). Can be NULL.

Table 16.8: Structure IP_SMTPC_MTA member list

338 CHAPTER 16 SMTP client (Add-on)

16.8 Resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the SMTP client presented in the tables below

have been measured on an ARM7 and a Cortex-M3 system. Details about the further

configuration can be found in the sections of the specific example.

Configuration used

#define SMTPC_OUT_BUFFER_SIZE 256

16.8.1 Resource usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

16.8.1.1 ROM usage

16.8.1.2 RAM usage

16.8.2 Resource usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

16.8.2.1 ROM usage

16.8.2.2 RAM usage

Addon ROM

embOS/IP SMTP client approximately 7.1Kbyte

Table 16.9: SMTPC client ROM usage ARM7

Addon RAM

embOS/IP SMTP client (w/o task stack) approximately 4.7Kbyte

Table 16.10: SMTPC client RAM usage ARM7

Addon ROM

embOS/IP SMTP client approximately 6.5Kbyte

Table 16.11: SMTPC client ROM usage Cortex-M3

Addon RAM

embOS/IP SMTP client w/o task stack approximately 4.7Kbyte

Table 16.12: SMTPC client RAM usage Cortex-M3

339

Chapter 17

FTP server (Add-on)

The embOS/IP FTP server is an optional extension to the TCP/IP stack. The FTP

server can be used with embOS/IP or with a different TCP/IP stack. All functions

which are required to add a FTP server task to your application are described in this

chapter.

340 CHAPTER 17 FTP server (Add-on)

17.1 embOS/IP FTP server

The embOS/IP FTP server is an optional extension which adds the FTP protocol to the

stack. FTP stands for File Transfer Protocol. It is the basic mechanism for moving files

between machines over TCP/IP based networks such as the Internet. FTP is a client/

server protocol, meaning that one machine, the client, initiates a file transfer by con-

tacting another machine, the server and making requests. The server must be oper-

ating before the client initiates his requests. Generally a client communicates with

one server at a time, while most servers are designed to work with multiple simulta-

neous clients.

The FTP server implements the relevant parts of the following RFCs.

The following table shows the contents of the embOS/IP FTP server root directory:

RFC# Description

[RFC 959] FTP - File Transfer Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc959.txt

Directory Contents

Application\ Contains the example application to run

the FTP server with embOS/IP.

Config Contains the FTP server configuration file.

Inc Contains the required include files.

IP Contains the FTP server sources.

IP\FS\

Contains the sources for the file system

abstraction layer and the read-only file

system. Refer to File system abstraction

layer function table on page 457 for

detailed information.

Windows\FTPserver\

Contains the source, the project files and

an executable to run embOS/IP FTP server

on a Microsoft Windows host.

Supplied directory structure of embOS/IP FTP server package

341

17.2 Feature list

• Low memory footprint.

• Multiple connections supported.

• Independent of the file system: Any file system can be used.

• Independent of the TCP/IP stack: Any stack with sockets can be used.

• Demo application included.

• Project for executable on PC for Microsoft Visual Studio included.

342 CHAPTER 17 FTP server (Add-on)

17.3 Requirements

TCP/IP stack

The embOS/IP FTP server requires a TCP/IP stack. It is optimized for embOS/IP, but

any RFC-compliant TCP/IP stack can be used. The shipment includes a Win32 simula-

tion, which uses the standard Winsock API and an implementation which uses the

socket API of embOS/IP.

Multi tasking

The FTP server needs to run as a separate thread. Therefore, a multi tasking system

is required to use the embOS/IP FTP server.

343

17.4 FTP basics

The File Transfer Protocol (FTP) is an application layer protocol. FTP is an unusual

service in that it utilizes two ports, a 'Data' port and a 'CMD' (command) port. Tradi-

tionally these are port 21 for the command port and port 20 for the data port. FTP

can be used in two modes, active and passive. Depending on the mode, the data port

is not always on port 20.

When an FTP client contacts a server, a TCP connection is established between the

two machines. The server does a passive open (a socket is listen) when it begins

operation; thereafter clients can connect with the server via active opens. This TCP

connection persists for as long as the client maintains a session with the server,

(usually determined by a human user) and is used to convey commands from the cli-

ent to the server, and the server replies back to the client. This connection is referred

to as the FTP command connection.

The FTP commands from the client to the server consist of short sets of ASCII char-

acters, followed by optional command parameters. For example, the FTP command to

display the current working directory is PWD (Print Working Directory). All commands

are terminated by a carriage return-linefeed sequence (CRLF) (ASCII 10,13; or Ctrl-

J, Ctrl-M). The servers replies consist of a 3 digit code (in ASCII) followed by some

explanatory text. Generally codes in the 200s are success and 500s are failures. See

the RFC for a complete guide to reply codes. Most FTP clients support a verbose

mode which will allow the user to see these codes as commands progress.

If the FTP command requires the server to move a large piece of data (like a file), a

second TCP connection is required to do this. This is referred to as the FTP data con-

nection (as opposed to the aforementioned command connection). In active mode

the data connection is opened by the server back to a listening client. In passive

mode the client opens also the data connection. The data connection persists only for

transporting the required data. It is closed as soon as all the data has been sent.

Application layer

Transport layer

Network layer

Link layer

FTP

TCP

Ethernet (IEEE 802.3), ...

344 CHAPTER 17 FTP server (Add-on)

17.4.1 Active mode FTP

In active mode FTP the client connects from a random unprivileged port P (P > 1023)

to the FTP server's command port, port 21. Then, the client starts listening to port

P+1 and sends the FTP command PORT P+1 to the FTP server. The server will then

connect back to the client's specified data port from its local data port, which is port

20.

Server

Data

Cmd

1026

Cmd

1027

Data

Client

345

17.4.2 Passive mode FTP

In passive mode FTP the client connects from a random unprivileged port P (P >

1023) to the FTP server's command port, port 21. In opposite to an active mode FTP

connection where the client opens a passive port for data transmission and waits for

the connection from server-side, the client sends in passive mode the “PASV” com-

mand to the server and expects an answer with the information on which port the

server is listening for the data connection.

After receiving this information, the client connects to the specified data port of the

server from its local data port.

Server

1655

Data

Cmd

1026

Cmd

1027

Data

Client

Data

346 CHAPTER 17 FTP server (Add-on)

17.4.3 FTP reply codes

Every FTP command is answered by one or more reply codes defined in [RFC 959]. A

reply is an acknowledgment (positive or negative) sent from server to user via the

control connection in response to FTP commands. The general form of a reply is a 3-

digit completion code (including error codes) followed by Space <SP>, followed by

one line of text and terminated by carriage return line feed <CRLF>. The codes are

for use by programs and the text is usually intended for human users.

The first digit of the reply code defines the class of response. There are 5 values for

the first digit:

• 1yz: Positive preliminary reply

• 2yz: Positive completion reply

• 3yz: Positive intermediate reply

• 4yz: Transient negative Completion reply

• 5yz: Permanent negative Completion reply

The second digit of the reply code defines the group of the response.

• x0z: Syntax - Syntax errors, syntactically correct commands that don't fit any

functional category, unimplemented or superfluous commands.

• x1z: Information - These are replies to requests for information, such as status

or help.

• x2z: Connections - Replies referring to the control and data connections.

• x3z: Authentication and accounting - Replies for the login process and accounting

procedures.

•x4z: Unspecified as yet.

• x5z: File system - These replies indicate the status of the Server file system vis-

a-vis the requested transfer or other file system action.

The third digit gives a finer gradation of meaning in each of the function categories,

specified by the second digit.

347

17.4.4 Supported FTP commands

embOS/IP FTP server supports a subset of the defined FTP commands. Refer to [RFC

959] for a complete detailed description of the FTP commands. The following FTP

commands are implemented:

FTP commands Description

CDUP Change to parent directory

CWD Change working directory

DELE Delete

LIST List

MKD Make directory

NLST Name list

NOOP No operation

PASS Password

PASV Passive

PORT Data port

PWD Print the current working directory

QUIT Logout

RETR Retrieve

RMD Remove directory

RNFR Renamr from

RNTO Rename to

SIZE Size of file

STOR Store

SYST System

TYPE Transfe r type

USER User name

XCUP Change to parent directory

XMKD Make directory

XPWD Print the current working directory

XRMD Remove directory

Table 17.1: embOS/IP FTP commands

348 CHAPTER 17 FTP server (Add-on)

17.5 Using the FTP server sample

Ready to use examples for Microsoft Windows and embOS/IP are supplied. If you use

another TCP/IP stack the sample OS_IP_FTPServer.c has to be adapted. The sample

application opens a port which listens on port 21 until an incoming connection is

detected. If a connection has been established IP_FTPS_Process() handles the cli-

ent request in an extra task, so that the server is further listening on port 21. The

example application requires a file system to make data files available. Refer to File

system abstraction layer on page 456 and File system abstraction layer on page 456

for detailed information.

17.5.1 Using the Windows sample

If you have MS Visual C++ 6.00 or any later version available, you will be able to

work with a Windows sample project using embOS/IP FTP server. If you do not have

the Microsoft compiler, an precompiled executable of the FTP server is also supplied.

The base directory of the Windows sample application is C:\FTP\.

Building the sample program

Open the workspace Start_FTPServer.dsw with MS Visual Studio (for example, dou-

ble-clicking it). There is no further configuration necessary. You should be able to

build the application without any error or warning message.

The server uses the IP address of the host PC on which it runs. Open a FTP client and

connect by entering the IP address of the host (127.0.0.1) to connect to the FTP

server. The server accepts anonymous logins. You can also login with the user name

"Admin" and the password "Secret".

17.5.2 Running the FTP server example on target hardware

The embOS/IP FTP server sample application should always be the first step to check

the proper function of the FTP server with your target hardware.

Add all source files located in the following directories (and their subdirectories) to

your project and update the include path:

• Application

• Config

• Inc

•IP

• IP\IP_FS\[NameOfUsedFileSystem]

It is recommended that you keep the provided folder structure.

The sample application can be used on the most targets without the need for chang-

ing any of the configuration flags. The server processes two connections using the

default configuration.

Note: Two connections mean that the target can handle up one target. A target

requires always two connection, one for the command transfer and one for the data

transfers. Every connection is handled in an separate task. Therefore, the FTP server

uses up to three tasks in the default configuration. One task which listens on port 21

and accepts connections and two tasks to process the accepted connection. To modify

the number of connections only the macro MAX_CONNECTIONS has to be modified.

349

17.6 Access control

The embOS/IP FTP server supports a fine-grained access permission scheme. Access

permissions can be defined on user-basis for every directory and every file. The

access permission of a directory or a file is a combination of the following attributes:

visible, readable and writable. To control the access permission four callback func-

tions have be implemented in the user application. The callback functions are defined

in the structure FTPS_ACCESS_CONTROL. For detailed information about these struc-

ture, refer to Structure FTPS_ACCESS_CONTROL on page 362.

17.6.1 pfFindUser()

Description

Callback function which checks if the user is valid.

Prototype

int (*pfFindUser) ( const char * sUser );

Return value

0 - UserID invalid or unknown

0 < - UserID, no password required

0 > - UserID, password required

Parameter

Example

enum {

USER_ID_ANONYMOUS = 1,

USER_ID_ADMIN

};

/*********************************************************************

* _FindUser

* Function description

* Callback function for user management.

* Checks if user name is valid.

* Return value

* 0 UserID invalid or unknown

* > 0 UserID, no password required

* < 0 - UserID, password required

static int _FindUser (const char * sUser) {

if (strcmp(sUser, "Admin") == 0) {

return - USER_ID_ADMIN;

}

if (strcmp(sUser, "anonymous") == 0) {

return USER_ID_ANONYMOUS;

}

return 0;

}

Parameter Description

sUser [IN] User name.

Table 17.2: pfFindUser() parameter list

350 CHAPTER 17 FTP server (Add-on)

17.6.2 pfCheckPass()

Description

Callback function which checks if the password is valid.

Prototype

int (*pfCheckPass) ( int UserId,

const char * sPass );

Parameter

Example

enum {

USER_ID_ANONYMOUS = 1,

USER_ID_ADMIN

};

/*********************************************************************

* _CheckPass

* Function description

* Callback function for user management.

* Checks user password.

* Return value

* 0 UserID know, password valid

* 1 UserID unknown or password invalid

static int _CheckPass (int UserId, const char * sPass) {

if ((UserId == USER_ID_ADMIN) && (strcmp(sPass, "Secret") == 0)) {

return 0;

} else {

return 1;

}

Parameter Description

UserId [IN] Id number

Pass [IN] Password string.

Table 17.3: pfCheckPass() parameter list

351

17.6.3 pfGetDirInfo()

Description

Callback function which checks the permissions of the connected user for every direc-

tory.

Prototype

int (*pfGetDirInfo) ( int UserId,

const char * sDirIn,

char * pDirOut,

int SizeOfDirOut );

Parameter

Example

/* Excerpt from IP_FTPServer.h */

#define IP_FTPS_PERM_VISIBLE (1 << 0)

#define IP_FTPS_PERM_READ (1 << 1)

#define IP_FTPS_PERM_WRITE (1 << 2)

/* Excerpt from OS_IP_FTPServer.c */

/*********************************************************************

* _GetDirInfo

* Function description

* Callback function for permission management.

* Checks directory permissions.

* Return value

* Returns a combination of the following:

* IP_FTPS_PERM_VISIBLE - Directory is visible as a directory entry

* IP_FTPS_PERM_READ - Directory can be read/entered

* IP_FTPS_PERM_WRITE - Directory can be written to

* Parameters

* UserId - User ID returned by _FindUser()

* sDirIn - Full directory path and with trailing slash

* sDirOut - Reserved for future use

* DirOutSize - Reserved for future use

* Notes

* In this sample configuration anonymous user is allowed to do anything.

* Samples for folder permissions show how to set permissions for different

* folders and users. The sample configures permissions for the following

* directories:

* - /READONLY/: This directory is read only and can not be written to.

* - /VISIBLE/ : This directory is visible from the folder it is located

* in but can not be accessed.

* - /ADMIN/ : This directory can only be accessed by the user "Admin".

static int _GetDirInfo(int UserId, const char * sDirIn, char * sDirOut, int DirOut-

Size) {

int Perm;

(void)sDirOut;

Parameter Description

UserId [IN] Id number

sDirIn [IN] Directory to check permission for

pDirOut [OUT] Directory that can be accessed

SizeOfDirOut [IN] Size of buffer addressed by pDirOut

Table 17.4: pfGetDirInfo() parameter list

352 CHAPTER 17 FTP server (Add-on)

(void)DirOutSize;

Perm = IP_FTPS_PERM_VISIBLE | IP_FTPS_PERM_READ | IP_FTPS_PERM_WRITE;

if (strcmp(sDirIn, "/READONLY/") == 0) {

Perm = IP_FTPS_PERM_VISIBLE | IP_FTPS_PERM_READ;

}

if (strcmp(sDirIn, "/VISIBLE/") == 0) {

Perm = IP_FTPS_PERM_VISIBLE;

}

if (strcmp(sDirIn, "/ADMIN/") == 0) {

if (UserId != USER_ID_ADMIN) {

return 0; // Only Admin is allowed for this directory

}

return Perm;

}

353

17.6.4 pfGetFileInfo()

Description

Callback function which checks the permissions of the connected user for every direc-

tory.

Prototype

int (*pfGetFileInfo) ( int UserId,

const char * sFileIn,

char * pFileOut,

int SizeOfFileOut );

Parameter

Additional information

Providing a function for file permissions is optional. If using permisisons on directory

level is sufficient for your needs pfGetFileInfo may be declared NULL in the

FTPS_ACCESS_CONTROL function table.

Example

/* Excerpt from IP_FTPServer.h */

#define IP_FTPS_PERM_VISIBLE (1 << 0)

#define IP_FTPS_PERM_READ (1 << 1)

#define IP_FTPS_PERM_WRITE (1 << 2)

/* Excerpt from OS_IP_FTPServer.c */

/*********************************************************************

* _GetFileInfo

* Function description

* Callback function for permission management.

* Checks file permissions.

* Return value

* Returns a combination of the following:

* IP_FTPS_PERM_VISIBLE - File is visible as a file entry

* IP_FTPS_PERM_READ - File can be read

* IP_FTPS_PERM_WRITE - File can be written to

* Parameters

* UserId - User ID returned by _FindUser()

* sFileIn - Full path to the file

* sFileOut - Reserved for future use

* FileOutSize - Reserved for future use

* Notes

* In this sample configuration all file accesses are allowed. File

* permissions are checked against directory permissions. Therefore it

* is not necessary to limit permissions on files that reside in a

* directory that already limits access.

* Setting permissions works the same as for _GetDirInfo() .

static int _GetFileInfo(int UserId, const char * sFileIn, char * sFileOut, int File-

OutSize) {

Parameter Description

UserId [IN] Id number

sFileIn [IN] File to check permission for

pFileOut [OUT] File that can be accessed

SizeOfFileOut [IN] Size of buffer addressed by pFileOut

Table 17.5: pfGetFileInfo() parameter list

354 CHAPTER 17 FTP server (Add-on)

int Perm;

(void)UserId;

(void)sFileIn;

(void)sFileOut;

(void)FileOutSize;

Perm = IP_FTPS_PERM_VISIBLE | IP_FTPS_PERM_READ | IP_FTPS_PERM_WRITE;

return Perm;

}

355

17.7 Configuration

The embOS/IP FTP server can be used without changing any of the compile time

flags. All compile time configuration flags are preconfigured with valid values, which

match the requirements of most applications.

The following types of configuration macros exist:

Binary switches "B"

Switches can have a value of either 0 or 1, for deactivated and activated respectively.

Actually, anything other than 0 works, but 1 makes it easier to read a configuration

file. These switches can enable or disable a certain functionality or behavior.

Switches are the simplest form of configuration macros.

Numerical values "N"

Numerical values are used somewhere in the source code in place of a numerical con-

stant. A typical example is the configuration of the sector size of a storage medium.

Alias "A"

A macro which operates like a simple text substitute. An example would be the define

U8, which the preprocessor would replace with unsigned char.

Function replacements "F"

Macros can basically be treated like regular functions although certain limitations

apply, as a macro is still put into the source code as simple text replacement. Func-

tion replacements are mainly used to add specific functionality to a module which is

highly hardware-dependent. This type of macro is always declared using brackets

(and optional parameters).

17.7.1 Compile time configuration switches

Type Symbolic name Default Description

FFTPS_WARN --

Defines a function to output warn-

ings. In debug configurations (DEBUG

== 1) FTPS_WARN maps to

IP_Warnf_Application()

FFTPS_LOG --

Defines a function to output logging

messages. In debug configurations

(DEBUG == 1) FTPS_LOG maps to

IP_Logf_Application().

NFTPS_AUTH_BUFFER_SIZE 32 Defines the size of the buffer used for

the authentication string.

NFTPS_BUFFER_SIZE 512 Defines the size of the send and

receive buffer of the FTP server.

NFTPS_MAX_PATH 128 Defines the maximum length of the

buffer used for the path string.

NFTPS_MAX_PATH_DIR 64 Defines the maximum length of the

buffer used for the directory string.

NFTPS_ERR_BUFFER_SIZE 256 Defines the size of the buffer used for

the authentication string.

356 CHAPTER 17 FTP server (Add-on)

17.7.2 FTP server system time

The FTP server requires a system time for the transmission of a complete file times-

tamp. FTP servers send only a piece of the timestamp of a file, either month, day

and year or month, day and time. For the decision which pieces of the timestamp

has to be transmitted, it compares the year of the current system time with the year

which is stored in the timestamp of the file. Depending on the result of this compari-

son either the year or the time will be send. The following two examples show the

output for both cases.

Example

1. If the value for year in the timestamp of the file is smaller then the value for year in

the current system time, year will be sent:

-rw-r--r-- 1 root 2000 Jan 1 2007 PAKET00.TXT

In this case, the FTP client leaves this column empty or fills the missing time with

00:00. The following screenshot shows the output of the Microsoft Windows command

line FTP client:

2. If the value for year in the timestamp of the file is identical to the value for year

in the current system time, the time (HH:MM) will be sent:

-rw-r--r-- 1 root 1000 Jul 29 11:04 PAKET01.TXT

In this case, the FTP client leaves this column empty or fills the missing year with

the current year. The following screenshot shows the output of the Microsoft Win-

dows command line FTP client:

In the example, the value for the current time and date is defined to 1980-01-01

00:00. Therefore, the output will be similar to example 1., since no real time clock

(RTC) has been implemented. Refer to pfGetTimeDate() on page 357 for detailed

information.

357

17.7.2.1 pfGetTimeDate()

Description

Returns the current system time.

Prototype

int (*pfGetTimeDate) ( void );

Return value

Current system time. If no real time clock is implemented, it should return

0x00210000 (1980-01-01 00:00)

Additional information

The format of the time is arranged as follows:

Bit 0-4: 2-second count (0-29)

Bit 5-10: Minutes (0-59)

Bit 11-15: Hours (0-23)

Bit 16-20: Day of month (1-31)

Bit 21-24: Month of year (1-12)

Bit 25-31: Number of years since1980 (0-127)

This function pointer is used in the FTPS_APPLICATION structure. Refer to Structure

FTPS_APPLICATION on page 363 for further information.

Example

static U32 _GetTimeDate(void) {

U32 r;

U16 Sec, Min, Hour;

U16 Day, Month, Year;

Sec = 0; // 0 based. Valid range: 0..59

Min = 0; // 0 based. Valid range: 0..59

Hour = 0; // 0 based. Valid range: 0..23

Day = 1; // 1 based. Means that 1 is 1.

// Valid range is 1..31 (depending on month)

Month = 1; // 1 based. Means that January is 1. Valid range is 1..12.

Year = 28; // 1980 based. Means that 2008 would be 28.

r = Sec / 2 + (Min << 5) + (Hour << 11);

r |= (U32)(Day + (Month << 5) + (Year << 9)) << 16;

return r;

}

358 CHAPTER 17 FTP server (Add-on)

17.8 API functions

Function Description

IP_FTPS_Process() Initializes and starts the embOS/IP FTP

server.

IP_FTPS_OnConnectionLimit() Returns when the connection is closed or a

fatal error occurs.

Table 17.6: embOS/IP FTP server interface function overview

359

17.8.1 IP_FTPS_Process()

Description

Initializes and starts the FTP server.

Prototype

int IP_FTPS_Process ( const IP_FTPS_API * pIP_API,

void * pConnectInfo,

const IP_FS_API * pFS_API,

const FTPS_APPLICATION * pApplication );

Parameter

Additional information

The structure type IP_FTPS_API contains mappings of the required socket functions

to the actual IP stack. This is required because the socket functions are slightly dif-

ferent on different systems. The connection info is the socket which was created

when the client has been connected to the command port (usually port 21). For

detailed information about the structure type IP_FS_API refer to Appendix A - File

system abstraction layer on page 455. For detailed information about the structure

type FTPS_APPLICATION refer to Structure FTPS_APPLICATION on page 363.

Parameter Description

pIP_API [IN] Pointer to a structure of type IP_FTPS_API.

pConnectInfo [IN] Pointer to the connection info.

pFS_API [IN] Pointer to the used file system API.

pApplication [IN] Pointer to a structure of type FTPS_APPLICATION.

Table 17.7: IP_FTPS_Process() parameter list

360 CHAPTER 17 FTP server (Add-on)

17.8.2 IP_FTPS_OnConnectionLimit()

Description

Returns when the connection is closed or a fatal error occurs.

Prototype

void IP_FTPS_OnConnectionLimit( const IP_FTPS_API * pIP_API,

void * CtrlSock );

Parameter

Additional information

The structure type IP_FTPS_API contains mappings of the required socket functions

to the actual IP stack. This is required because the socket functions are slightly dif-

ferent on different systems.

Parameter Description

pIP_API [IN] Pointer to a structure of type IP_FTPS_API.

CtrlSock [IN] Pointer to the socket which is related to the command connec-

tion.

Table 17.8: IP_FTPS_OnConnectionLimit() parameter list

361

17.9 FTP server data structures

17.9.1 Structure IP_FTPS_API

Description

This structure contains the pointer to the socket functions which are required to use

the FTP server.

Prototype

typedef struct {

int (*pfSend) (const unsigned char * pData, int len, FTPS_SOCKET Socket);

int (*pfReceive) (unsigned char * pData, int len, FTPS_SOCKET Socket);

FTPS_SOCKET (*pfConnect) (FTPS_SOCKET CtrlSocket, U16 Port);

void (*pfDisconnect) (FTPS_SOCKET DataSocket);

FTPS_SOCKET (*pfListen) (FTPS_SOCKET CtrlSocket,U16 * pPort,U8 * pIPAddr);

int (*pfAccept) (FTPS_SOCKET CtrlSocket, FTPS_SOCKET * pDataSocket);

} IP_FTPS_API;

Member Description

pfSend Callback function that sends data to the client on socket level.

pfReceive Callback function that receives data from the client on socket level.

pfConnect Callback function that handles the connect back to a FTP client on

socket level if not using passive mode.

pfDisconnect Callback function that disconnects a connection to the FTP client on

socket level if not using passive mode.

pfListen Callback function that binds the server to a port and addr.

pfAccept Callback function that accepts incoming connections.

Table 17.9: Structure IP_FTPS_API member list

362 CHAPTER 17 FTP server (Add-on)

17.9.2 Structure FTPS_ACCESS_CONTROL

Description

This structure contains the pointer to the access control callback functions.

Prototype

typedef struct {

int (*pfFindUser) ( const char * sUser );

int (*pfCheckPass) ( int UserId,

const char * sPass );

int (*pfGetDirInfo) ( int UserId,

const char * sDirIn,

char * sDirOut,

int SizeOfDirOut );

} FTPS_ACCESS_CONTROL;

Example

Refer to Access control on page 349 for an example.

Member Description

pfFindUser Callback function that checks if the user is valid.

pfCheckPass Callback function that checks if the password is valid.

pfGetDirInfo Callback function that checks the permissions of the connected user

for every directory.

pfGetFileInfo

Callback function that checks the permisisons of the connected user

for every file. May be NULL if directory permisisons are sufficient for

your needs.

Table 17.10: Structure FTPS_ACCESS_CONTROL member list

363

17.9.3 Structure FTPS_APPLICATION

Description

Used to store application specific parameters.

Prototype

typedef struct {

FTPS_ACCESS_CONTROL * pAccess;

U32 (*pfGetTimeDate) (void);

} FTPS_APPLICATION;

Example

For additional information to structure FTPS_ACCESS_APPLICATION refer to Struc-

ture FTPS_ACCESS_CONTROL on page 362. For additional information to function

pointer pfGetTimeDate() refer to FTP server system time on page 356.

Example

/* Excerpt from OS_IP_FTPServer.c */

/*********************************************************************

* FTPS_ACCESS_CONTROL

* Description

* User/pass data table

static FTPS_ACCESS_CONTROL _Access_Control = {

_FindUser,

_CheckPass,

_GetDirInfo

};

*********************************************************************

* _GetTimeDate

static U32 _GetTimeDate(void) {

U32 r;

U16 Sec, Min, Hour;

U16 Day, Month, Year;

Sec = 0; // 0 based. Valid range: 0..59

Min = 0; // 0 based. Valid range: 0..59

Hour = 0; // 0 based. Valid range: 0..23

Day = 1; // 1 based. Means that 1 is 1.

// Valid range is 1..31 (depending on month)

Month = 1; // 1 based. Means that January is 1. Valid range is 1..12.

Year = 28; // 1980 based. Means that 2008 would be 28.

r = Sec / 2 + (Min << 5) + (Hour << 11);

r |= (U32)(Day + (Month << 5) + (Year << 9)) << 16;

return r;

}

*********************************************************************

* FTPS_APPLICATION

* Description

* Application data table, defines all application specifics

* used by the FTP server

static const FTPS_APPLICATION _Application = {

&_Access_Control,

_GetTimeDate

};

Member Description

pAccess Pointer to the FTPS_ACCESS_APPLCIATION structure.

pfGetTimeDate Pointer to the function which returns the current system time.

Table 17.11: Structure FTPS_APPLICATION member list

364 CHAPTER 17 FTP server (Add-on)

17.10 Resource usage

The ROM usage depends on the compiler options, the compiler version and the used

CPU. The memory requirements of the FTP server presented in the tables below have

been measured on an ARM7 and a Cortrex-M3 system. Details about the further con-

figuration can be found in the sections of the specific example.

Configuration used

#define FTPS_AUTH_BUFFER_SIZE 32

#define FTPS_BUFFER_SIZE 512

#define FTPS_MAX_PATH 128

#define FTPS_MAX_PATH_DIR 64

#define FTPS_ERR_BUFFER_SIZE (FTPS_BUFFER_SIZE / 2)

17.10.1 ROM usage on an ARM7 system

The following resource usage has been measured on an ARM7 system using IAR

Embedded Workbench V6.30.6, Thumb mode, no interwork, size optimization.

17.10.2 ROM usage on a Cortex-M3 system

The following resource usage has been measured on a Cortex-M3 system using IAR

Embedded Workbench V6.30.6, size optimization.

17.10.3 RAM usage:

Almost all of the RAM used by the FTP server is taken from task stacks. The amount

of RAM required for every child task depends on the configuration of your server. The

table below shows typical RAM requirements for your task stacks.

Note: The FTP server requires at least 1 child task.

The approximately RAM usage for the FTP server can be calculated as follows:

RAM usage = 0.2 Kbytes + ParentTask + (NumberOfChildTasks * 1.8 Kbytes)

Example: FTP server accepting up only 1 connection

RAM usage = 0.2 Kbytes + 0.5 Kbytes + (1 * 1.8 Kbytes)

RAM usage = 2.5 Kbytes

Addon ROM

embOS/IP FTP server approximately 6.6Kbyte

Table 17.12: FTP server ROM usage ARM7

Addon ROM

embOS/IP FTP server approximately 5.6Kbyte

Table 17.13: FTP server ROM usage Cortex-M3

Task Description RAM

ParentTask Listens for incoming connections. approximately 500 bytes

ChildTask Handles a request. approximately 1800 bytes

Table 17.14: FTP server RAM usage

365

Chapter 18

FTP client (Add-on)

The embOS/IP FTP client is an optional extension to the TCP/IP stack. The FTP client

can be used with embOS/IP or with a different TCP/IP stack. All functions which are

required to add a FTP client to your application are described in this chapter.

366 CHAPTER 18 FTP client (Add-on)

18.1 embOS/IP FTP client

The embOS/IP FTP client is an optional extension which adds the client part of FTP

protocol to the stack. FTP stands for File Transfer Protocol. It is the basic mechanism

for moving files between machines over TCP/IP based networks such as the Internet.

FTP is a client/server protocol, meaning that one machine, the client, initiates a file

transfer by contacting another machine, the server and making requests.

The FTP client implements the relevant parts of the following RFCs.

The following table shows the contents of the embOS/IP FTP client root directory:

RFC# Description

[RFC 959] FTP - File Transfer Protocol

Direct download: ftp://ftp.rfc-editor.org/in-notes/rfc959.txt

Directory Contents

Application\ Contains the example application to run

the FTP client with embOS/IP.

Config Contains the FTP client configuration file.

Inc Contains the required include files.

IP Contains the FTP client sources.

IP\FS\

Contains the sources for the file system

abstraction layer and the read-only file

system. Refer to File system abstraction

layer function table on page 457 for

detailed information.

Windows\FTPclient\

Contains the source, the project files and

an executable to run embOS/IP FTP client

on a Microsoft Windows host.

Supplied directory structure of embOS/IP FTP client package

367

18.2 Feature list

• Low memory footprint.

• Multiple connections supported.

• Independent of the file system: Any file system can be used.

• Independent of the TCP/IP stack: Any stack with sockets can be used.

• Demo application included.

• Project for executable on PC for Microsoft Visual Studio included.

368 CHAPTER 18 FTP client (Add-on)

18.3 Requirements

TCP/IP stack

The embOS/IP FTP client requires a TCP/IP stack. It is optimized for embOS/IP, but

any RFC-compliant TCP/IP stack can be used. The shipment includes a Win32 simula-

tion, which uses the standard Winsock API and an implementation which uses the

socket API of embOS/IP.

369

18.4 FTP basics