utils

Juha Heinanen

   TutPro Inc.

   Copyright © 2008-2009 Juha Heinanen
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. http_query_timeout (int)
              3.2. forward_active (int)
              3.3. pres_db_url (string)
              3.4. xcap_table (string)

        4. 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

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1. http_query_timeout (int)
        3.2. forward_active (int)
        3.3. pres_db_url (string)
        3.4. xcap_table (string)

   4. 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

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
   2.2. External Libraries or Applications

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. Parameters

   3.1. http_query_timeout (int)
   3.2. forward_active (int)
   3.3. pres_db_url (string)
   3.4. xcap_table (string)

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. Functions

   4.1. http_query(url, result)
   4.2. xcap_auth_status(watcher_uri, presentity_uri)

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.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE,
   FAILURE_ROUTE, and BRANCH_ROUTE.

   Example 1.5. http_query() usage
...
http_query("http://tutpro.com/index.php?r_uri=$(ru{s.escape.param})&f_uri=$(fu{s
.escape.param})",
           "$var(result)")
switch ($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) {
        t_relay();
    } else {
        send_reply("403", "Forbidden");
    }
}
...

5. MI Commands

   5.1. forward_list
   5.2. forward_switch
   5.3. forward_filter
   5.4. forward_proxy

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 ?
