PROTO_MSRP module

Admin Guide

Overview

The proto_msrp module provides the MSRP protocol stack, meaning the network read/wite (plain and TLS), message parsing and assembling, transactional layer and the basic signalling operations.

Once loaded, you will be able to define MSRP listeners in your script, by adding its IP, and optionally the listening port, in your configuration file, similar to this example:

...
socket=msrp:127.0.0.1:65432
socket=msrps:127.0.0.1:65431
...

Dependencies

OpenSIPS Modules

The following modules must be loaded before this module:

• tls_mgm - you need to load this module if using MSRPS (secure) sockets. Via this module you will manage the SSL certificates

External Libraries or Applications

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

• None.

Exported Parameters

send_timeout (integer)

Time in milliseconds after a MSRP connection will be closed if it is not available for blocking writing in this interval (and OpenSIPS wants to send something on it).

Default value is 100 ms.

Set send_timeout parameter

...
modparam("proto_msrp", "send_timeout", 200)
...

max_msg_chunks (integer)

The maximum number of chunks that a SIP message is expected to arrive via MSRP. If a packet is received more fragmented than this, the connection is dropped (either the connection is very overloaded and this leads to high fragmentation - or we are the victim of an ongoing attack where the attacker is sending the traffic very fragmented in order to decrease our performance).

Default value is 4.

Set max_msg_chunks parameter

...
modparam("proto_msrp", "max_msg_chunks", 8)
...

tls_handshake_timeout (integer)

Sets the timeout (in milliseconds) for the SSL handshake sequence to complete. It may be necessary to increase this value when using a CPU intensive cipher for the connection to allow time for keys to be generated and processed.

The timeout is invoked during acceptance of a new connection (inbound) and during the wait period when a new session is being initiated (outbound).

Default value is 100.

Set tls_handshake_timeout variable

param("proto_msrp", "tls_handshake_timeout", 200) # number of milliseconds

cert_check_on_conn_reusage (integer)

This parameter turns on or off the extra checking/matching of the TLS domain (SSL certificate) when comes to reusing an existing TLS connection. Without this extra check, only IP and port of the connections will be check (in order to re-use an existing connection). With this extra check, the connection to be reused must have the same SSL certificate as the one set for the current signaling operation.

This checking is done only when comes to send SIP traffic via TLS and it is applied only against connections that were created / initiated by OpenSIPS (as TLS client). Any accepte connection (as TLS server) will automatically match (the extra test will be skipped).

Default value is 0 (disabled).

Set cert_check_on_conn_reusage parameter

...
modparam("proto_msrp", "cert_check_on_conn_reusage", 1)
...

trace_destination (string)

Trace destination as defined in the tracing module. Currently the only tracing module is proto_hep. Network events such as connect, accept and connection closed events shall be traced along with errors that could appear in the process.

**WARNING:**A tracing module must be loaded in order for this parameter to work. (for example proto_hep).

Default value is none(not defined).

Set trace_destination parameter

...
modparam("proto_hep", "hep_id", "[hep_dest]10.0.0.2;transport=tcp;version=3")

modparam("proto_msrp", "trace_destination", "hep_dest")
...

trace_on (int)

This controls whether tracing for MSRP is on or not. You still need to define trace destinationin order to work, but this value will be controlled using MI function msrp trace.

Set trace_on parameter

...
modparam("proto_msrp", "trace_on", 1)
...

trace_filter_route (string)

Define the name of a route in which you can filter which connections will be trace and which connections won’t be. In this route you will have information regarding source and destination ips and ports for the current connection. To disable tracing for a specific connection the last call in this route must be drop, any other exit mode resulting in tracing the current connection ( of course you still have to define a trace destination and trace must be on at the time this connection is opened.

Caution

Filtering on ip addresses and ports can be made using $si and $sp for matching either the entity that is connecting to OpenSIPS or the entity to which OpenSIPS is connecting. The name might be misleading ($si meaning the source ip if you read the docs) but in reality it is simply the socket other than the OpenSIPS socket. In order to match OpenSIPS interface (either the one that accepted the connection or the one that initiated a connection) $socket_in(ip) (ip) and $socket_in(port) (port) can be used.

Danger

If trace on is set to 0 or tracing is deactived via the mi command msrp trace this route won’t be called.

Set trace_filter_route parameter

...
modparam("proto_msrp", "trace_filter_route", "msrp_filter")
...
/* all MSRP connections will go through this route if tracing is activated
 * and a trace destination is defined */
route[msrp_filter] {
  ...
  /* all connections opened from/by ip 1.1.1.1:8000 will be traced
     on interface 1.1.1.10:5060(opensips listener)
     all the other connections won't be */
   if ( $si == "1.1.1.1" && $sp == 8000 &&
    $socket_in(ip) == "1.1.1.10"  && $socket_in(port) == 5060)
    exit;
  else
    drop;
}
...

Exported MI Functions

msrp_trace

Name: msrp_trace

Parameters:

• trace_mode(optional): set MSRP tracing on and off. This parameter can be missing and the command will show the current tracing status for this module( on or off ); Possible values:
  • on
  • off

MI FIFO Command Format:

:msrp_trace:_reply_fifo_file_
trace_mode
_empty_line_

Contributors

By Commit Statistics

Top contributors by DevScore⁽¹⁾, authored commits⁽²⁾ and lines added/removed⁽³⁾

#	Name	DevScore	Commits	Lines++	Lines—
1.	Bogdan-Andrei Iancu (@bogdan-iancu)	69	16	4913	607
2.	Vlad Patrascu (@rvlad-patrascu)	33	22	442	368
3.	Stefan Darius (@dariusstefan)	10	5	357	90
4.	Liviu Chircu (@liviuchircu)	6	4	23	21
5.	Razvan Crainea (@razvancrainea)	5	3	4	4

(1) DevScore = author_commits + author_lines_added / (project_lines_added / project_commits) + author_lines_deleted / (project_lines_deleted / project_commits)

(2) including any documentation-related commits, excluding merge commits

(3) ignoring whitespace edits, renamed files and auto-generated files

By Commit Activity

#	Name	Commit Activity
1.	Stefan Darius (@dariusstefan)	Jun 2026 - Jul 2026
2.	Razvan Crainea (@razvancrainea)	Sep 2022 - Jun 2026
3.	Liviu Chircu (@liviuchircu)	Apr 2022 - Jul 2022
4.	Vlad Patrascu (@rvlad-patrascu)	Mar 2022 - Jul 2022
5.	Bogdan-Andrei Iancu (@bogdan-iancu)	Mar 2022 - May 2022

(1) including any documentation-related commits, excluding merge commits

Documentation

Contributors

Last edited by: Razvan Crainea (@razvancrainea), Bogdan-Andrei Iancu (@bogdan-iancu).

License

All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0