Juha Heinanen

TutPro Inc.

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Exported Parameters
3.1. http_query_timeout (int)
3.2. forward_active (int)
3.3. pres_db_url (string)
3.4. xcap_table (string)
4. Exported Functions
4.1. http_query(url, result)
4.2. xcap_auth_status(watcher_uri, presentity_uri)
5. MI Commands
5.1. forward_list
5.2. forward_switch
5.3. forward_filter
5.4. forward_proxy
6. Configuration syntax

List of Examples

1.1. Set http_query_timeout parameter
1.2. Set forward_active parameter
1.3. Set pres_db_url parameter
1.4. Set xcap_table parameter
1.5. http_query() usage
1.6. xcap_auth_status() usage
1.7. forward_list usage
1.8. forward_switch usage
1.9. forward_filter usage
1.10. forward_proxy usage

Chapter 1. Admin Guide

1. Overview

This module implements various utility functions that are not SIP related.

Function http_query allows Kamailio to issue an HTTP GET request and get access to parts of the reply.

The forward functionality allows Kamailio to configure forwarding at runtime with FIFO commands. The forwarding is executed in the pre script call back and therefore handled before the routing script is executed on the current message. The callback is not installed on default, thus this functionality has no runtime overhead when its deactivated.

Function xcap_auth_status can be used to check from presence server database, if watcher is authorized to subscribe event “presence” of presentity.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

  • a database module if xcap_auth_status function is enabled.

2.2. External Libraries or Applications

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

  • libcurl.

3. Exported Parameters

3.1. http_query_timeout (int)

Defines in seconds how long Kamailio waits response from HTTP server.

Default value is null, i.e., xcap_auth_status function is disabled.

Example 1.1. Set http_query_timeout parameter

modparam("utils", "http_query_timeout", 2)

3.2. forward_active (int)

Defines if the forwarding callback should be installed.

Default value is “0”.

Example 1.2. Set forward_active parameter

					modparam("utils", "forward_active", 1)

3.3. pres_db_url (string)

Defines presence server database URL. If not given, xcap_auth_status function is disabled.

There is no default value.

Example 1.3. Set pres_db_url parameter

modparam("utils", "pres_db_url", "mysql://foo:secret@localhost/pres")

3.4. xcap_table (string)

Defines name of xcap table in presence server database.

Default value is “xcap”.

Example 1.4. Set xcap_table parameter

modparam("utils", "xcap_table", "pres_xcap")

4. Exported Functions

4.1.  http_query(url, result)

Sends HTTP GET request according to URL given in “url” parameter, which is a string that may contain pseudo variables.

If HTTP server returns a class 2xx or 3xx reply, first line of reply's body (if any) is stored in “result” parameter, which must be a writable pseudo variable.

Function returns reply code of HTTP reply or -1 if something went wrong.


Example 1.5. http_query() usage

switch ($retcode) {

4.2.  xcap_auth_status(watcher_uri, presentity_uri)

Function checks from presence server database if watcher is authorized to subscribe event “presence” of presentity. Sphere checking is not included.

Both watcher_uri and presentity_uri are pseudo variables. Function returns ACTIVE_STATUS, if subscription is allowed and PENDING_STATUS, TERMINATED_STATUS, or WAITING_STATUS otherwise. See presence/subscribe.h for the corresponding integer codes. In case of error, function returns -1.

Function can be used from REQUEST_ROUTE.

Example 1.6. xcap_auth_status() usage

if (method=="MESSAGE") {
    xcap_auth_status("$fu", $ru");
    if ($retcode == 1) {
    } else {
        send_reply("403", "Forbidden");

5. MI Commands

5.1. forward_list

List active forward rules.

No parameters.

Example 1.7. forward_list usage

kamctl fifo forward_list
id switch                         filter proxy
 0    off      REGISTER:INVITE:SUBSCRIBE host-a.domain-a:5060

5.2. forward_switch

This command can be used to activate or deactivate forwarding rules. The syntax of this configuration string is described in 1.6. (switch_setting_list).

Example 1.8. forward_switch usage

kamctl fifo sp_forward_switch 0=on

5.3. forward_filter

Can be used to specify the filter for a certain id. Messages will only be forwarded if one of the filters matches the message.

There are special filters and regular filters. Special filters are:

  • REQUEST (matches on every request)
  • REPLY (matches on every reply)

Regular filters are arbitrary strings not containing the delimiter ':'. They are matched against the request method names of the sip messages. The syntax of this configuration string is described in 1.6. (filter_setting_list).

Example 1.9. forward_filter usage

kamctl fifo sp_forward_filter 0=REGISTER:INVITE

5.4. forward_proxy

This command can be used to configure forwarding rules. Specifies the destination for a certain id. Messages will be forwarded to this destination if the preconditions hold (matching id, filter, and switch). The syntax of this configuration string is described in 1.6. (proxy_setting_list).

Example 1.10. forward_proxy usage

kamctl fifo sp_forward_proxy 0=host-c.domain-c:5060

6. Configuration syntax

This grammar specify the usable configuration syntax

  • switch_setting_list ::= switch_setting { "," switch_setting }
  • filter_setting_list ::= switch_setting { "," switch_setting }
  • proxy_setting_list ::= proxy_setting { "," proxy_setting }
  • switch_setting ::= id "=" switch
  • filter_setting ::= id "=" filter_list
  • proxy_setting ::= id "=" proxy
  • switch ::= ( "off" | "on" )
  • filter_list ::= filter { ":" filter }
  • proxy ::= host ":" port
  • filter ::= ( special_filter | regular_filter )
  • special_filter ::= ( "REQUEST" | "REPLY" )
  • regular_filter ::= ? [^:]* ?
  • host ::= char { char }
  • char ::= ? A-Za-z0-9.-_ ?
  • id ::= number
  • port ::= number
  • number ::= digit {digit}
  • digit ::= ? 0-9 ?