DLGS Module

Daniel-Constantin Mierla

Edited by

Daniel-Constantin Mierla


Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. active_lifetime (int)
3.2. init_lifetime (int)
3.3. finish_lifetime (int)
3.4. timer_interval (int)
4. Functions
4.1. dlgs_init(src, dst, data)
4.2. dlgs_update()
4.3. dlgs_count(field, op, data)
4.4. dlgs_tags_add(vtag)
4.5. dlgs_tags_rm(vtag)
4.6. dlgs_tags_count(vtag)
5. RPC Commands
5.1. dlgs.list
5.2. dlgs.briefing
5.3. dlgs.get
5.4. dlgs.getall
5.5. dlgs.stats

List of Examples

1.1. Set active_lifetime parameter
1.2. Set init_lifetime parameter
1.3. Set finish_lifetime parameter
1.4. Set timer_interval parameter
1.5. dlgs_init usage
1.6. dlgs_update usage
1.7. dlgs_count usage
1.8. dlgs_tags_add usage
1.9. dlgs_tags_rm usage
1.10. dlgs_tags_count usage
1.11. dlgs.list usage
1.12. dlgs.briefing usage
1.13. dlgs.get usage
1.14. dlgs.get usage
1.15. dlgs.stats usage

Chapter 1. Admin Guide

1. Overview

This module tracks dialogs (active calls) in stateless mode and offers statistics about them.

The dialogs can be tagged and the number of dialogs with the same tag can be retrieved in configuration file.

The module aims to be a lightweight alternative to dialog module, to enable SIP server instances (such as an edge proxy or SBC) to know how many active calls they route, without being a call stateful proxy. The tracking of active calls is done without any dependency on other modules, in other words, it does not need the tm (transaction management) module.

2. Dependencies

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

3.1. active_lifetime (int)

The lifetime in seconds of an active dialog in memory. A dialog is considered active after the ACK of 200OK for INVITE.

Default value is 10800 (3 hours).

Example 1.1. Set active_lifetime parameter

...
modparam("dlgs", "active_lifetime", 3600)
...

3.2. init_lifetime (int)

The lifetime in seconds of an initial dialog in memory. A dialog is in initial state from the moment of creation until it gets to active state. If the dialog stays longer in the initial state, then it is destroyed by the next timer cleanup.

Default value is 180 (3 minutes).

Example 1.2. Set init_lifetime parameter

...
modparam("dlgs", "init_lifetime", 240)
...

3.3. finish_lifetime (int)

The lifetime in seconds of a finished dialog in memory. A dialog is finished if the initial INVITE was not answered or the BYE was received. Once this lifetime passes, the dialog record is removed from memory by the next timer cleanup.

Default value is 10 (seconds).

Example 1.3. Set finish_lifetime parameter

...
modparam("dlgs", "finish_lifetime", 20)
...

3.4. timer_interval (int)

The value in secods to run the timer callback function for cleaning up dialogs past the lifetime limit.

Default value is 30.

Example 1.4. Set timer_interval parameter

...
modparam("dlgs", "timer_interval", 60)
...

4. Functions

4.1.  dlgs_init(src, dst, data)

Start track the dialog corresponding to the current SIP message. It has to be used for INVITE messages.

This function can be used from REQUEST_ROUTE, BRANCH_ROUTE, ONREPLY_ROUTE, ONSEND_ROUTE.

Example 1.5. dlgs_init usage

...
onsend_route {
    ...
    if(is_method("INVITE")) {
        dlgs_init("$fu", "$tu", "my data");
    }
    ...
}
...

4.2.  dlgs_update()

Update dialog state. It has to be used for SIP requests only, the SIP responses are handled automatically.

This function can be used from REQUEST_ROUTE, BRANCH_ROUTE, ONSEND_ROUTE.

Example 1.6. dlgs_update usage

...
request_route {
    ...
    if(is_method("ACK|BYE|CANCEL")) {
        dlgs_update();
    }
    ...
}
...

4.3.  dlgs_count(field, op, data)

Return the number of dialogs matching the filter specified by the parameters. It does not count the dialogs that are finished (not answered or terminated with BYE).

The field parameter can be: 'src', 'dst', 'data' to specify what dialog attribute has to be used for matching. It can be also 'any' to get the count of all ongoing dialogs.

The op parameter can be: 'eq' - equal; 'ne' - not equal; 're' - regex; 'sw' - start with; 'fm' - fnmatch.

In case of error or no dialog matched, it returns -1 or other negative (false) value.

This function can be used from ANY_ROUTE.

Example 1.7. dlgs_count usage

...
request_route {
    ...
    $var(count) = dlgs_count("src", "eq", "$fu");
    if($var(count) > 0) {
        # caller has ongoing dialogs
    }
    ...
    $var(allcalls) = dlgs_count("any", "eq", "*");
    if($var(allcalls) > 0) {
        # there are ongoing dialogs
    }
    ...
}
...

4.4.  dlgs_tags_add(vtag)

Add a tag to current dialog.

This function can be used from ANY_ROUTE.

Example 1.8. dlgs_tags_add usage

...
request_route {
    ...
    dlgs_tags_add("$si");
    ...
}
...

4.5.  dlgs_tags_rm(vtag)

Remove a tag from current dialog.

This function can be used from ANY_ROUTE.

Example 1.9. dlgs_tags_rm usage

...
request_route {
    ...
    dlgs_tags_rm("$si");
    ...
}
...

4.6.  dlgs_tags_count(vtag)

Count all tags for ongoing dialogs matching the parameter.

It returns -1 if no tag for ongoing dialogs is matched or there was an error.

This function can be used from ANY_ROUTE.

Example 1.10. dlgs_tags_count usage

...
request_route {
    ...
    $var(tcount) = dlgs_tags_count("$si");
    ...
}
...

5. RPC Commands

5.1.  dlgs.list

List dialog records.

Example 1.11. dlgs.list usage

...
kamctl rpc dlgs.list
...

5.2.  dlgs.briefing

List dialog records with fewer attributes per record.

Example 1.12. dlgs.briefing usage

...
kamctl rpc dlgs.briefing
...

5.3.  dlgs.get

Prototype: dlgs.get field op data

List first dialog record matching the filter. The parameters have the same meaning like those for dlgs_count(...).

Example 1.13. dlgs.get usage

...
kamctl rpc dlgs.get src eq sip:alice@sipserver.com
...

5.4.  dlgs.getall

Prototype: dlgs.getall field op data

List all dialog records matching the filter. The parameters have the same meaning like those for dlgs_count(...).

Example 1.14. dlgs.get usage

...
kamctl rpc dlgs.get src eq sip:alice@sipserver.com
...

5.5.  dlgs.stats

Return dialog statistics.

Example 1.15. dlgs.stats usage

...
kamctl rpc dlgs.stats
...