MSRP UA Module

Through an internal API and exported script and MI functions, the module allows OpenSIPS to set up MSRP sessions via SIP and exchange messages as an MSRP endpoint.

The module makes use of the proto_msrp module for the MSRP protocol stack and the b2b_entities module for the SIP UAC/UAS functionalities.

1.2. Usage from Script and External API

In order to start a SIP call carying MSRP from OpenSIPS you can use the msrp_ua_start_session MI function. Alternatively, to answer a SIP session with MSRP you can use the msrp_ua_answer() script function.

When a UAC or UAS session is successfully established(ACK sent/received) the E_MSRP_SESSION_NEW event is triggered. After this point, you may receive MSRP messages or Reports, signaled by the E_MSRP_MSG_RECEIVED and E_MSRP_REPORT_RECEIVED events.

Note that the E_MSRP_REPORT_RECEIVED event covers both actual MSRP REPORT requests as well as negative MSRP transaction responses and local send timeouts(which should be treated the same as a received timeout transaction response).

You can send MSRP messages to the peer with the msrp_ua_send_message MI function.

1.3. Dependencies

1.3.1. OpenSIPS Modules

The following modules must be loaded before this module:

proto_msrp
b2b_entities

1.3.2. External Libraries or Applications

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

None.

1.4. Exported Parameters

1.4.1. `hash_size` (int)

The size of the hash table that stores the MSRP session information. It is the 2 logarithmic value of the real size.

Default value is “10” (1024 records).

Example 1.1. Set hash_size parameter

...
modparam("msrp_ua", "hash_size", 16)
...

1.4.2. `cleanup_interval` (int)

The interval between full iterations of the sessions table in order to clean up expired MSRP sessions.

Default value is “60”.

Example 1.2. Set cleanup_interval parameter

...
modparam("msrp_ua", "cleanup_interval", 30)
...

1.4.3. `max_duration` (integer)

The maximum duration of a call. If set to 0, there will be no limitation.

The default value is 12 * 3600 seconds (12 hours).

Example 1.3. max_duration parameter example

...
modparam("msrp_ua", "max_duration", 7200)
...

1.4.4. `my_uri` (string)

The MSRP URI of the OpenSIPS endpoint. This URI will be advertised in the SDP offer provided to peers when setting up a session and should match one of the MSRP listeners defined in the script.

The session-id part of the URI should be ommited.

If the port is not set explicitly, the default value of 2855 wil be assumed

Example 1.4. my_uri parameter usage

...
modparam("msrp_ua", "my_uri", "msrp://opensips.org:2855;tcp")
...

1.4.5. `advertised_contact` (string)

Contact to be used in the generated SIP requests. For sessions answered by OpenSIPS, if it is not set, it is constructed dynamically from the socket where the initiating request was received.

This parameter is mandatory when using the msrp_ua_start_session MI function.

Example 1.5. advertised_contact parameter usage

...
modparam("msrp_ua", "advertised_contact", "sip:oss@opensips.org")
...

1.4.6. `relay_uri` (string)

URI of an MSRP relay to use for both accepted and initiated sessions.

Credentials for the MSRP client are provided via the uac_auth module by setting the credential module parameter.

If not set, no relay will be used.

Example 1.6. relay_uri parameter usage

...
modparam("msrp_ua", "relay_uri", "msrp://opensips.org:2856;tcp")
...

1.5. Exported Functions

1.5.1. `msrp_ua_answer(content_types)`

This functions answers an initial INVITE offering a new MSRP messaging session. After this function is used to initialize the session, the call will be completely handled by the B2B engine.

Parameters:

content_types (string) - content types adevertised in the accept-types SDP attribute. At least one of the content types in this list must match the types offered by the peer in its SDP offer.

This function can be used only from a request route.

Example 1.7. msrp_ua_answer() usage

...
if (!has_totag() && is_method("INVITE")) {
	msrp_ua_answer("text/plain");
	exit;
}
...

1.6. Exported MI Functions

1.6.1. `msrp_ua_send_message`

Sends a new MSRP message to the peer.

Name: msrp_ua_send_message

Parameters

session_id (string) - the MSRP session identifier ("session-id" part of the MSRP URI).
mime (string, optional) - MIME content type of this message. If missing, an empty message will be sent.
body (string, optional) - actual message body. If missing, an empty message will be sent.
success_report (string, optional) - string indicating whether to request an MSRP Success Report. Possible values are yes or no. If the parameter is missing or is set to "no" the SEND request will not include a Success-Report header.
failure_report (string, optional) - string indicating whether to request an MSRP Failure Report. Possible values are yes, no or partial, as specified in MSRP. If the parameter is missing or is set to "yes" the SEND request will not include a Failure-Report header. Note that if the header field is not present, the receving MSRP endpoint must treat it the same as a Failure-Report header with a value of "yes".

MI FIFO Command Format:

opensips-cli -x mi msrp_ua_send_message \
	session_id=5addd9e7b74fa44fbace68a4fc562293 \
	mime=text/plain body=Hello success_report=yes

1.6.2. `msrp_ua_start_session`

Starts a MSRP session.

The advertised_contact is mandatory if this function is used.

Name: msrp_ua_start_session

Parameters

content_types (string) - content types adevertised in the accept-types SDP attribute.
from_uri (string) - From URI to be used in the INVITE.
to_uri (string) - To URI to be used in the INVITE.
ruri (string) - Request URI and destination of the INVITE.

MI FIFO Command Format:

opensips-cli -x mi msrp_ua_start_session \
	text/plain sip:oss@opensips.org \
	sip:alice@opensips.org sip:alice@opensips.org

1.6.3. `msrp_ua_list_sessions`

Lists information about ongoing MSRP sessions.

Name: msrp_ua_list_sessions

Parameters

None.

MI FIFO Command Format:

opensips-cli -x mi msrp_ua_list_sessions

1.6.4. `msrp_ua_end_session`

Terminate an ongoing MSRP session.

Name: msrp_ua_end_session

Parameters

session_id (string) - the MSRP session identifier ("session-id" part of the MSRP URI).

MI FIFO Command Format:

opensips-cli -x mi msrp_ua_end_session \
	5addd9e7b74fa44fbace68a4fc562293

1.7. Exported Events

1.7.1. `E_MSRP_SESSION_NEW`

This event is triggered when a new MSRP session is successfully established(ACK sent/received).

Parameters:

from_uri - The URI in the SIP From header of the answered INVITE.
to_uri - The URI in the SIP To header of the answered INVITE.
ruri - The SIP Request URI of the answered INVITE.
session_id - The MSRP session identifier ("session-id" part of the MSRP URI).
content_types - The content types offered by the peer in the accept-types SDP attribute.

1.7.2. `E_MSRP_SESSION_END`

This event is triggered when an ongoing MSRP session is terminted (session expires or BYE is received; terminating a session via the msrp_ua_end_session MI function is not included).

Parameters:

session_id - The MSRP session identifier ("session-id" part of the MSRP URI).

1.7.3. `E_MSRP_MSG_RECEIVED`

This event is triggered when receiving a new, non-empty MSRP SEND request from the peer.

Parameters:

session_id - The MSRP session identifier ("session-id" part of the MSRP URI).
content_type - The content type of this message.
body - The actual message body.

1.7.4. `E_MSRP_REPORT_RECEIVED`

This event is triggered when:

a MSRP REPORT request is received
a failure transaction response is received
a local timeout for a SEND request occured.

Parameters:

session_id - The MSRP session identifier ("session-id" part of the MSRP URI).
message_id - The value of the Message-ID header field.
status - The value of the Status header field.
byte_range - The value of the Byte-Range header field.

Chapter 2. Developer Guide

2.1. Overview

In order to answer a SIP session carying MSRP the init_uas() function should be used. Conversely for starting a MSRP call as a UAC, one can use the init_uac() function.

After initializing the session with either of the above functions, the SIP call will be further handled by the module and notifications regarding significant SIP level events and received MSRP requests and responses will be delivered via registering callback functions.

MSRP SEND requests can be sent with the send_message() function after the sessions is established, which will be signaled by the msrp_ua_notify_cb_f callback with the MSRP_UA_SESS_ESTABLISHED event.

Received MSRP requests, transaction responses and local send timeouts will be signaled via the msrp_ua_req_cb_f and msrp_ua_rpl_cb_f callbacks.

2.2. Available Functions

2.2.1. `init_uas(msg, accept_types, hdl)`

This function will intialize a MSRP UA session based on a received SIP INVITE.

Meaning of the parameters is as follows:

struct sip_msg *msg - the SIP message
str *accept_types - the value of the "accept-types" attribute to include in the SDP offer.
struct msrp_ua_handler *hdl - handler structure used to register the callbacks for SIP level and MSRP level notifications.

Example 2.1. struct msrp_ua_handler structure

struct msrp_ua_handler {
	/* name of this registration */
	str *name;
	/* parameter to be passed to msrp_req_cb and msrp_rpl_cb callbacks */
	void *param;
	/* callback for SIP level notifications */
	msrp_ua_notify_cb_f notify_cb;
	/* callback for receving MSRP requests */
	msrp_ua_req_cb_f msrp_req_cb;
	/* callback for receving MSRP responses */
	msrp_ua_rpl_cb_f msrp_rpl_cb;
};

Example 2.2. msrp_ua_notify_cb_f prototype

typedef int (*msrp_ua_notify_cb_f)(struct msrp_ua_notify_params *params,
	void *hdl_param);

Example 2.3. struct msrp_ua_notify_params structure

struct msrp_ua_notify_params {
	/* event type */
	enum msrp_ua_event_type event;
	/* SIP message */
	struct sip_msg *msg;
	/* SDP "accept-types" attribute in case of MSRP_UA_SESS_ESTABLISHED event */
	str *accept_types;
	/* MSRP UA session ID */
	str *session_id;
};

Example 2.4. enum msrp_ua_event_type

enum msrp_ua_event_type {
	/* session established (ACK sent/received) */
	MSRP_UA_SESS_ESTABLISHED = 1,
	/* failed to establish session (negative reply/timeout etc.) */
	MSRP_UA_SESS_FAILED,
	/* BYE received/sent(in case of session timeout) */
	MSRP_UA_SESS_TERMINATED
};

Example 2.5. msrp_ua_req_cb_f prototype

typedef int (*msrp_ua_req_cb_f)(struct msrp_msg *req, void *hdl_param);

Example 2.6. msrp_ua_rpl_cb_f prototype

/* an MSRP transaction timeout will be signaled by calling this callback
 * with a NULL rpl parameter */
typedef int (*msrp_ua_rpl_cb_f)(struct msrp_msg *rpl, void *hdl_param);

2.2.2. `init_uac(accept_types, from_uri, to_uri, ruri, hdl)`

This function will intialize a MSRP UA session by sending a SIP INVITE to a destination.

Meaning of the parameters is as follows:

str *accept_types - the value of the "accept-types" attribute to include in the SDP offer.
str *from_uri - URI to use in the From header of the INVITE.
str *to_uri - URI to use in the To header of the INVITE.
str *ruri - Request URI to use in the for the INVITE.
struct msrp_ua_handler *hdl - handler structure used to register the callbacks for SIP level and MSRP level notifications.

2.2.3. `end_session(session_id)`

This function terminates an MSRP session.

Meaning of the parameters is as follows:

str *session_id - MSRP UA session ID.

2.2.4. `send_message(session_id, mime, body, failure_report, success_report)`

This functions sends an MSRP SEND request to the peer.

Meaning of the parameters is as follows:

str *session_id - MSRP UA session ID.
str *mime - MIME content type of this message. If NULL, an empty message will be sent.
str *body - actual message body. If NULL, an empty message will be sent.
enum msrp_failure_report_type failure_report - MSRP Failure Report type - yes, no or partial.
int success_report - indication whether to request an MSRP Failure Report or not.

Example 2.7. enum msrp_failure_report_type

enum msrp_failure_report_type {
	MSRP_FAILURE_REPORT_YES,
	MSRP_FAILURE_REPORT_PARTIAL,
	MSRP_FAILURE_REPORT_NO
};

Chapter 3. Contributors

3.1. By Commit Statistics

Table 3.1. Top contributors by DevScore⁽¹⁾, authored commits⁽²⁾ and lines added/removed⁽³⁾

	Name	DevScore	Commits	Lines ++	Lines --
1.	Vlad Patrascu (@rvlad-patrascu)	54	16	4038	293
2.	Maksym Sobolyev (@sobomax)	4	2	5	5
3.	Razvan Crainea (@razvancrainea)	3	1	11	1
4.	Liviu Chircu (@liviuchircu)	3	1	8	8
5.	Bogdan-Andrei Iancu (@bogdan-iancu)	3	1	1	1

(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. Regarding imported patches/code, we do our best to count the work on behalf of the proper owner, as per the "fix_authors" and "mod_renames" arrays in opensips/doc/build-contrib.sh. If you identify any patches/commits which do not get properly attributed to you, please submit a pull request which extends "fix_authors" and/or "mod_renames".

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

3.2. By Commit Activity

Table 3.2. Most recently active contributors⁽¹⁾ to this module

	Name	Commit Activity
1.	Maksym Sobolyev (@sobomax)	Feb 2023 - Feb 2023
2.	Vlad Patrascu (@rvlad-patrascu)	May 2022 - Jan 2023
3.	Razvan Crainea (@razvancrainea)	Aug 2022 - Aug 2022
4.	Liviu Chircu (@liviuchircu)	Jul 2022 - Jul 2022
5.	Bogdan-Andrei Iancu (@bogdan-iancu)	May 2022 - May 2022

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

Chapter 4. Documentation

4.1. Contributors

Last edited by: Vlad Patrascu (@rvlad-patrascu).

MSRP UA Module

Chapter 1. Admin Guide

1.1. Overview

1.2. Usage from Script and External API

1.3. Dependencies

1.3.1. OpenSIPS Modules

1.3.2. External Libraries or Applications

1.4. Exported Parameters

1.4.1. hash_size (int)

1.4.2. cleanup_interval (int)

1.4.3. max_duration (integer)

1.4.4. my_uri (string)

1.4.5. advertised_contact (string)

1.4.6. relay_uri (string)

1.5. Exported Functions

1.5.1. msrp_ua_answer(content_types)

1.6. Exported MI Functions

1.6.1. msrp_ua_send_message

1.6.2. msrp_ua_start_session

1.6.3. msrp_ua_list_sessions

1.6.4. msrp_ua_end_session

1.7. Exported Events

1.7.1. E_MSRP_SESSION_NEW

1.7.2. E_MSRP_SESSION_END

1.7.3. E_MSRP_MSG_RECEIVED

1.7.4. E_MSRP_REPORT_RECEIVED

Chapter 2. Developer Guide

2.1. Overview

2.2. Available Functions

2.2.1. init_uas(msg, accept_types, hdl)

2.2.2. init_uac(accept_types, from_uri, to_uri, ruri, hdl)

2.2.3. end_session(session_id)

2.2.4. send_message(session_id, mime, body, failure_report, success_report)

Chapter 3. Contributors

3.1. By Commit Statistics

3.2. By Commit Activity

Chapter 4. Documentation

4.1. Contributors

1.4.1. `hash_size` (int)

1.4.2. `cleanup_interval` (int)

1.4.3. `max_duration` (integer)

1.4.4. `my_uri` (string)

1.4.5. `advertised_contact` (string)

1.4.6. `relay_uri` (string)

1.5.1. `msrp_ua_answer(content_types)`

1.6.1. `msrp_ua_send_message`

1.6.2. `msrp_ua_start_session`

1.6.3. `msrp_ua_list_sessions`

1.6.4. `msrp_ua_end_session`

1.7.1. `E_MSRP_SESSION_NEW`

1.7.2. `E_MSRP_SESSION_END`

1.7.3. `E_MSRP_MSG_RECEIVED`

1.7.4. `E_MSRP_REPORT_RECEIVED`

2.2.1. `init_uas(msg, accept_types, hdl)`

2.2.2. `init_uac(accept_types, from_uri, to_uri, ruri, hdl)`

2.2.3. `end_session(session_id)`

2.2.4. `send_message(session_id, mime, body, failure_report, success_report)`