kamailio/modules/sdpops

SDPOPS Module

Daniel-Constantin Mierla



Edited by

Daniel-Constantin Mierla



Copyright � 2011 asipto.com
__________________________________________________________________

Table of Contents

1. Admin Guide

1. Overview
2. Dependencies

2.1. Kamailio Modules
2.2. External Libraries or Applications

3. Parameters
4. Functions

4.1. sdp_remove_codecs_by_id(list)
4.2. sdp_remove_codecs_by_name(list)
4.3. sdp_remove_line_by_prefix(string)
4.4. sdp_keep_codecs_by_id(list [, mtype])
4.5. sdp_keep_codecs_by_name(list [, mtype])
4.6. sdp_with_media(type)
4.7. sdp_remove_media(type)
4.8. sdp_with_codecs_by_id(list)
4.9. sdp_with_codecs_by_name(list)
4.10. sdp_print(level)
4.11. sdp_get(avpvar)
4.12. sdp_content()

List of Examples

1.1. sdp_remove_codecs_by_id usage
1.2. sdp_remove_codecs_by_name usage
1.3. sdp_remove_line_by_prefix usage
1.4. sdp_keep_codecs_by_id usage
1.5. sdp_keep_codecs_by_name usage
1.6. sdp_with_media usage
1.7. sdp_remove_media usage
1.8. sdp_with_codecs_by_id usage
1.9. sdp_with_codecs_by_name usage
1.10. sdp_print usage
1.11. sdp_get usage
1.12. sdp_content usage

Chapter 1. Admin Guide

Table of Contents

1. Overview
2. Dependencies

2.1. Kamailio Modules
2.2. External Libraries or Applications

3. Parameters
4. Functions

4.1. sdp_remove_codecs_by_id(list)
4.2. sdp_remove_codecs_by_name(list)
4.3. sdp_remove_line_by_prefix(string)
4.4. sdp_keep_codecs_by_id(list [, mtype])
4.5. sdp_keep_codecs_by_name(list [, mtype])
4.6. sdp_with_media(type)
4.7. sdp_remove_media(type)
4.8. sdp_with_codecs_by_id(list)
4.9. sdp_with_codecs_by_name(list)
4.10. sdp_print(level)
4.11. sdp_get(avpvar)
4.12. sdp_content()

1. Overview

This module provides functions for checking and managing the SDP
payloads of SIP messages.

Examples of functions this module offers: remove codecs from SDP, check
the media stream types and return attributes of SDP document. For the
full list of the features provided by this module and the
implementation state, please read the list of exported functions.

2. Dependencies

2.1. Kamailio Modules
2.2. External Libraries or Applications

2.1. Kamailio Modules

The following modules must be loaded before this module:
* none.

2.2. External Libraries or Applications

The following libraries or applications must be installed before
running Kamailio with this module loaded:
* None

3. Parameters

The module does not export any config parameter yet.

4. Functions

4.1. sdp_remove_codecs_by_id(list)
4.2. sdp_remove_codecs_by_name(list)
4.3. sdp_remove_line_by_prefix(string)
4.4. sdp_keep_codecs_by_id(list [, mtype])
4.5. sdp_keep_codecs_by_name(list [, mtype])
4.6. sdp_with_media(type)
4.7. sdp_remove_media(type)
4.8. sdp_with_codecs_by_id(list)
4.9. sdp_with_codecs_by_name(list)
4.10. sdp_print(level)
4.11. sdp_get(avpvar)
4.12. sdp_content()

4.1. sdp_remove_codecs_by_id(list)

Remove the codecs provided in the parameter 'list' from all media
streams found in SDP payload. The parameter 'list' must be one item or
a comma separated list of numeric codec IDs. The parameter can be a
static string or a variable holding the list of numeric codec IDs.

This function can be used from ANY_ROUTE.

Example 1.1. sdp_remove_codecs_by_id usage
...
# remove PCMU
sdp_remove_codecs_by_id("0");
# remove PCMU, PCMA and GSM
sdp_remove_codecs_by_id("0,8,3");
...

4.2. sdp_remove_codecs_by_name(list)

Remove the codecs provided in the parameter 'list' from all media
streams found in SDP payload. The parameter 'list' must be one item or
a comma separated list of codec names. The parameter can be a static
string or a variable holding the list of codec names.

This function can be used from ANY_ROUTE.

Example 1.2. sdp_remove_codecs_by_name usage
...
# remove PCMU
sdp_remove_codecs_by_name("PCMU");
# remove PCMU, PCMA and GSM
sdp_remove_codecs_by_name("PCMU,PCMA,GSM");
...

4.3. sdp_remove_line_by_prefix(string)

Remove all SDP attribute lines beginning with 'string' in all media
streams.

This function can be used from ANY_ROUTE.

Example 1.3. sdp_remove_line_by_prefix usage
...
if ($si == "2001:DB8::8:800:200C:417A"
and ( has_body("application/sdp") or has_body("multipart/mixed")))
{
xlog("L_INFO", "Cleaning ugly SDP from $si\n");
sdp_remove_codecs_by_name("X-NSE");
sdp_remove_line_by_prefix("a=X-");
}

...

4.4. sdp_keep_codecs_by_id(list [, mtype])

Keep only the codecs provided in the parameter 'list' from all media
streams found in SDP payload. The parameter 'list' must be one item or
a comma separated list of numeric codec IDs. The parameter can be a
static string or a variable holding the list of numeric codec IDs.

Optional parameter mtype can be provided to apply the operations only
to the streams matching m=mtype.

This function can be used from ANY_ROUTE.

Example 1.4. sdp_keep_codecs_by_id usage
...
# keep only PCMU
sdp_keep_codecs_by_id("0");
# keep PCMU, PCMA and GSM in audio stream
sdp_keep_codecs_by_id("0,8,3", "audio");
...

4.5. sdp_keep_codecs_by_name(list [, mtype])

Keep only the codecs provided in the parameter 'list' from all media
streams found in SDP payload. The parameter 'list' must be one or a
comma separated list of codec names. The parameter can be a static
string or a variable holding the list of codec names.

Optional parameter mtype can be provided to apply the operations only
to the streams matching m=mtype.

This function can be used from ANY_ROUTE.

Example 1.5. sdp_keep_codecs_by_name usage
...
# keep only PCMU
sdp_keep_codecs_by_name("PCMU");
# keep PCMU, PCMA and GSM
sdp_keep_codecs_by_name("PCMU,PCMA,GSM");
...

4.6. sdp_with_media(type)

Return true of the SDP has 'media=type ...' line. Useful to check the
content of the RTP sessions, such as 'audio' or 'video'. The parameter
can be static string or variable holding the media type.

This function can be used from ANY_ROUTE.

Example 1.6. sdp_with_media usage
...
# check for video stream
if(sdp_with_media("video"))
{
# the session has a video stream
}
...

4.7. sdp_remove_media(type)

Remove the streams that match on 'm=type ...' line. The parameter can
be static string or variable holding the media type.

This function can be used from ANY_ROUTE.

Example 1.7. sdp_remove_media usage
...
# remove video stream
sdp_remove_media("video");
...

4.8. sdp_with_codecs_by_id(list)

Returns true if any of the codecs provided in the parameter 'list' from
all media streams is found in SDP payload. The parameter 'list' must be
one or a comma separated list of numeric codec IDs. The parameter can
be a static string or a variable holding the list of numeric codec IDs.

This function can be used from ANY_ROUTE.

Example 1.8. sdp_with_codecs_by_id usage
...
# test for PCMU
if(sdp_with_codecs_by_id("0")) { ... }
# test for PCMU, PCMA or GSM
if(sdp_with_codecs_by_id("0,8,3")) { ... }
...

4.9. sdp_with_codecs_by_name(list)

Returns true if any of the codecs provided in the parameter 'list' from
all media streams is found in SDP payload. The parameter 'list' must be
one item or a comma separated list of codec names. The parameter can be
a static string or a variable holding the list of codec names.

This function can be used from ANY_ROUTE.

Example 1.9. sdp_with_codecs_by_name usage
...
# test for PCMU
if(sdp_with_codecs_by_name("PCMU")) { ... }
# test for PCMU, PCMA or GSM
if(sdp_with_codecs_by_name("PCMU,PCMA,GSM")) { ... }
...

4.10. sdp_print(level)

Print the SDP internal structure to log 'level'. The parameter can be
static integer or variable holding the integer value of the log level.

This function can be used from ANY_ROUTE.

Example 1.10. sdp_print usage
...
# print the SDP
sdp_print("1");
...

4.11. sdp_get(avpvar)

Store the SDP part of message body in an AVP. Return 1 if SDP is found,
-1 on error and -2 if there is no SDP part in the message body.

This function can be used from ANY_ROUTE.

Example 1.11. sdp_get usage
...
sdp_get("$avp(sdp)");
...

4.12. sdp_content()

Return true if the SIP message has SDP body or a SDP part in body.

This function can be used from ANY_ROUTE.

Example 1.12. sdp_content usage
...
if(sdp_content()) {
...
}
...