mangler Module

Gabriel Vasile

   FhG FOKUS

Edited by

Gabriel Vasile

   Copyright © 2003 Fill in here
   Revision History
   Revision $Revision: 5901 $ $Date$
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Dependencies

              1.2.1. OpenSIPS Modules
              1.2.2. External Libraries or Applications

        1.3. Exported Parameters

              1.3.1. contact_flds_separator (string)

        1.4. Exported Functions

              1.4.1. sdp_mangle_ip(pattern, newip)
              1.4.2. sdp_mangle_port(offset)
              1.4.3. encode_contact(encoding_prefix, public_ip)
              1.4.4. decode_contact()
              1.4.5. decode_contact_header()

   List of Examples

   1.1. Set db_url parameter
   1.2. sdp_mangle_ip usage
   1.3. sdp_mangle_port usage
   1.4. encode_contact usage
   1.5. decode_contact usage
   1.6. decode_contact_header usage

Chapter 1. Admin Guide

1.1. Overview

   This is a module to help with SDP mangling. Note: This module
   is obselete and will be removed for the 1.5.0 release.

1.2. Dependencies

1.2.1. OpenSIPS Modules

   The following modules must be loaded before this module:
     * No dependencies on other OpenSIPS modules.

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSIPS with this module loaded:
     * None.

1.3. Exported Parameters

1.3.1. contact_flds_separator (string)

   First char of this parameter is used as separator for
   encoding/decoding Contact header.

Warning

   First char of this field must be set to a value which is not
   used inside username,password or other fields of contact.
   Otherwise it is possible for the decoding step to fail/produce
   wrong results.

   Default value is “*”.

   Example 1.1. Set db_url parameter
...
modparam("mangler", "contact_flds_separator", "-")
...

   then an encoded uri might look
   sip:user-password-ip-port-protocol@PublicIP

1.4. Exported Functions

1.4.1.  sdp_mangle_ip(pattern, newip)

   Changes IP addresses inside SDP package in lines describing
   connections like c=IN IP4 Currently in only changes IP4
   addresses since IP6 probably will not need to traverse NAT :)

   The function returns negative on error, or number of
   replacements + 1.

   Meaning of the parameters is as follows:
     * pattern - A pair ip/mask used to match IP's located inside
       SDP package in lines c=IN IP4 ip. This lines will only be
       mangled if located IP is in the network described by this
       pattern. Examples of valid patterns are
       “10.0.0.0/255.0.0.0” or “10.0.0.0/8” etc.
     * newip - A string representing the new IP to be put inside
       SDP package if old IP address matches pattern.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

   Example 1.2. sdp_mangle_ip usage
...
sdp_mangle_ip("10.0.0.0/8","193.175.135.38");
...

1.4.2.  sdp_mangle_port(offset)

   Changes ports inside SDP package in lines describing media like
   m=audio 13451.

   The function returns negative on error, or number of
   replacements + 1.

   Meaning of the parameters is as follows:
     * offset - A string representing an integer which will be
       added/subtracted from the located port.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

   Example 1.3. sdp_mangle_port usage
...
sdp_mangle_port("-12000");
...

1.4.3.  encode_contact(encoding_prefix, public_ip)

   This function will encode uri-s inside Contact header in the
   following manner
   sip:username:password@ip:port;transport=protocol goes
   sip:enc_pref*username*ip*port*protocol@public_ip * is the
   default separator.

   The function returns negative on error, 1 on success.

   Meaning of the parameters is as follows:
     * encoding_prefix - Something to allow us to determine that a
       contact is encoded publicip--a routable IP, most probably
       you should put your external IP of your NAT box.
       public_ip - The public IP which will be used in the encoded
       contact, as described by the example above.

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

   Example 1.4. encode_contact usage
...
if (src_ip == 10.0.0.0/8) encode_contact("enc_prefix","193.175.135.38");

...

1.4.4.  decode_contact()

   This function will decode the URI in first line in packets
   which come with encoded URI in the following manner
   sip:enc_pref*username*ip*port*protocol@public_ip goes to
   sip:username:password@ip:port;transport=protocol It uses the
   default set parameter for contact encoding separator.

   The function returns negative on error, 1 on success.

   Meaning of the parameters is as follows:

   This function can be used from REQUEST_ROUTE.

   Example 1.5. decode_contact usage
...
if (uri =~ "^enc*") { decode_contact(); }
...

1.4.5.  decode_contact_header()

   This function will decode URIs inside Contact header in the
   following manner
   sip:enc_pref*username*ip*port*protocol@public_ip goes to
   sip:username:password@ip:port;transport=protocol. It uses the
   default set parameter for contact encoding separator.

   The function returns negative on error, 1 on success.

   Meaning of the parameters is as follows:

   This function can be used from REQUEST_ROUTE, ONREPLY_ROUTE.

   Example 1.6. decode_contact_header usage
...
if (uri =~ "^enc*") { decode_contact_header(); }
...
