NOSIP Module

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Daniel-Constantin Mierla

   <miconda@gmail.com>

   Copyright © 2014 asipto.com
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. msg_match (str)
              3.2. msg_skip (str)

        4. Event Routes

              4.1. event_route[nosip:msg]

        5. Examples of Usage

   List of Examples

   1.1. Set msg_match parameter
   1.2. Set msg_match parameter
   1.3. event_route[nosip:msg] usage
   1.4. event_route[nosip:msg] use case

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. msg_match (str)
        3.2. msg_skip (str)

   4. Event Routes

        4.1. event_route[nosip:msg]

   5. Examples of Usage

1. Overview

   This module provides a way to get access to non-SIP packages received
   by Kamailio via its SIP worker processes. The content of such packages
   is available in the $mb variable inside the event_route[nosip:msg].

   Note that packets with size less than 32 bytes are discarded, this
   threshold being set to avoid handling the NAT keepalive packets coming
   from devices. The limit is planned to be made configurable. Also, by
   default Kamailio writes a log messages in case of SIP parsing error,
   that can be controlled via 'corelog' global parameter.

   Besides the content of the packet, $si and $sp provide the source IP
   and port, allowing to do filtering and authorization.

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:
     * 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. msg_match (str)
   3.2. msg_skip (str)

3.1. msg_match (str)

   Regular expression to match against content of the packet in order to
   execute the event_route[nosip:msg].

   Default value is empty.

   Example 1.1. Set msg_match parameter
...
modparam("nosip", "msg_match", "^KREQUEST-")
...

3.2. msg_skip (str)

   Regular expression to match against content of the packet in order to
   skip execution the event_route[nosip:msg].

   Default value is empty.

   Example 1.2. Set msg_match parameter
...
modparam("nosip", "msg_skip", "^GET ")
...

4. Event Routes

   4.1. event_route[nosip:msg]

4.1.  event_route[nosip:msg]

   Event route block to be executed when a non-sip message is received by
   a SIP worker process.

   The routename parameter can be a static string or a dynamic string
   value with config variables.

   The sleep parameter represent the number of seconds to suspend the
   processing of a SIP request. Maximum value is 100. The parameter can be
   a static integer or a variable holding an integer.

   Since the SIP request handling is resumed in another process, the
   config file execution state is practically lost. Therefore beware that
   the execution of config after resume will end once the route[routename]
   is finished.

   This function can be used from REQUEST_ROUTE.

   Example 1.3. event_route[nosip:msg] usage
...
loadmodule "nosip.so"
...
event_route[nosip:msg] {
   xlog("non-sip packet received - content [[$mb]] from [$si:$sp]\n");
   exit;
}
...

5. Examples of Usage

   There can be many useful cases when one wants to get a SIP worker back
   to handle a suspended SIP transaction. While this could be achieved via
   XMLRPC or HTTP for TCP workers, UDP workers are the least loaded in
   terms of network interaction layer (ie., there is no overhead for
   connections management like for TCP).

   Parsing of the non-sip message can be done using config file actions:
   functions, expressions with variables and transformations.

   Next is a basic example of parsing a message from the network and
   resuming the transaction.

   Example 1.4. event_route[nosip:msg] use case
...
# expect: :KREQUEST-RESUME-TRANSACTION:tindex:tlabel:routename:
# example: :KREQUEST-RESUME-TRANSACTION:4242:8686:RESUME:
loadmodule "nosip.so"
...
event_route[nosip:msg] {
    xlog("non-sip packet received - content [[$mb]] from [$si:$sp]\n");

    # must be a trusted IP
    if($si!="127.0.0.1") {
        exit;
    }

    # validation of the format and resume transaction
    if($mb=~":KREQUEST-RESUME-TRANSACTION:[0-9]+:[0-9]+:[a-zA-Z0-9]+:$") {
        $var(tindex) = $(mb{s.select,1,:});
        $var(tlabel) = $(mb{s.select,2,:});
        $var(rname) = $(mb{s.select,3,:});
        t_continue("$var(tindex)", "$var(tlabel)", "$var(rname)");
    }
    exit;
}

route[RESUME] {
    ...
}
...
