Peering Module

Juha Heinanen

   <jh@tutpro.com>

Edited by

Juha Heinanen

   <jh@tutpro.com>

   Copyright © 2008 Juha Heinanen
   Revision History
   Revision $Revision: 5906 $ $Date: 2009-07-21 10:45:05 +0300
                              (Tue, 21 Jul 2009) $
     __________________________________________________________

   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. radius_config (string)
              1.3.2. verify_destination_service_type (integer)
              1.3.3. verify_source_service_type (integer)

        1.4. Exported Functions

              1.4.1. verify_destination()
              1.4.2. verify_source()

   List of Examples

   1.1. radius_config parameter usage
   1.2. verify_destination_service_type parameter usage
   1.3. verify_source_service_type parameter usage
   1.4. verify_destination() usage
   1.5. verify_source() usage

Chapter 1. Admin Guide

1.1. Overview

   Peering module allows SIP providers (operators or
   organizations) to verify from a broker if source or destination
   of a SIP request is a trusted peer.

   In order to participate in the trust community provided by a
   broker, each SIP provider registers with the broker the domains
   (host parts of SIP URIs) that they serve. When a SIP proxy of a
   provider needs to send a SIP request to a non-local domain, it
   can find out from the broker using verify_destination()
   function if the non-local domain is served by a trusted peer.
   If so, the provider receives from the broker a hash of the SIP
   request and a timestamp that it includes in the request to the
   non-local domain. When a SIP proxy of the non-local domain
   receives the SIP request, it, in turn, can verify from the
   broker using verify_source() function if the request came from
   a trusted peer.

   Verification functions communicate with the broker using Radius
   protocol. Sample FreeRADIUS configuration files for broker's
   Radius server are available from http://www.wirlab.net/tsi/.

   Comments and suggestions for improvements are welcome.

1.2. Dependencies

1.2.1. OpenSIPS Modules

   The module depends on the following modules (in the other words
   the listed modules must be loaded before this module):
     * none

1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before compilling OpenSIPS with this module loaded:
     * radiusclient-ng 0.5.0 or higher -- library and development
       files. See
       http://developer.berlios.de/projects/radiusclient-ng/.

1.3. Exported Parameters

1.3.1. radius_config (string)

   This is the location of the configuration file of radius client
   libraries.

   Default value is
   "/opt/etc/radiusclient-ng/radiusclient.conf".

   Example 1.1. radius_config parameter usage
modparam("peering", "radius_config", "/etc/broker/radiusclient.conf")

1.3.2. verify_destination_service_type (integer)

   This is the value of the Service-Type Radius attribute to be
   used, when sender of SIP Request verifies request's destination
   using verify_destination() function.

   Default value is dictionary value of "Sip-Verify-Destination"
   Service-Type.

   Example 1.2. verify_destination_service_type parameter usage
modparam("peering", "verify_destination_service_type", 21)

1.3.3. verify_source_service_type (integer)

   This is the value of the Service-Type Radius attribute to be
   used, when receiver of SIP Request verifies request's source
   using verify_source() function.

   Default value is dictionary value of "Sip-Verify-Source"
   Service-Type.

   Example 1.3. verify_source_service_type parameter usage
modparam("peering", "verify_source_service_type", 22)

1.4. Exported Functions

1.4.1. verify_destination()

   Function verify_destination() queries from broker's Radius
   server if domain (host part) of Request URI is served by a
   trusted peer. Radius request contains the following
   attributes/values:
     * User-Name - Request-URI host
     * SIP-URI-User - Request-URI user
     * SIP-From-Tag - From tag
     * SIP-Call-Id - Call id
     * Service-Type - verify_destination_service_type

   Function returns value 1 if domain of Request URI is served by
   a trusted peer and -1 otherwise. In case of positive result,
   Radius server returns a set of SIP-AVP reply attributes. Value
   of each SIP-AVP is of form:

   [#]name(:|#)value

   Value of each SIP-AVP reply attribute is mapped to an OpenSIPS
   AVP. Prefix # in front of name or value indicates a string name
   or string value, respectively.

   One of the SIP-AVP reply attributes contains a string that the
   source peer must include "as is" in a P-Request-Hash header
   when it sends the SIP request to the destination peer. The
   string value may, for example, be of form hash@timestamp, where
   hash contains a hash calculated by the broker based on the
   attributes of the query and some local information and
   timestamp is the time when the calculation was done.

   AVP names used in reply attributes are assigned by the broker.

   This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.

   Example 1.4. verify_destination() usage
...
if (verify_destination()) {
   append_hf("P-Request-Hash: $avp(i:200)\r\n");
}
...

1.4.2. verify_source()

   Function verify_source() queries from broker's Radius server if
   SIP request was received from a trusted peer. Radius request
   contains the following attributes/values:
     * User-Name - Request-URI host
     * SIP-URI-User - Request-URI user
     * SIP-From-Tag - From tag
     * SIP-Call-Id - Call id
     * SIP-Request-Hash - body of P-Request-Hash header
     * Service-Type - verify_source_service_type

   Function returns value 1 if SIP request was received from a
   trusted peer and -1 otherwise. In case of positive result,
   Radius server may return a set of SIP-AVP reply attributes.
   Value of each SIP-AVP is of form:

   [#]name(:|#)value

   Value of each SIP-AVP reply attribute is mapped to an OpenSIPS
   AVP. Prefix # in front of name or value indicates a string name
   or string value, respectively.

   AVP names used in reply attributes are assigned by the broker.

   This function can be used from REQUEST_ROUTE and FAILURE_ROUTE.

   Example 1.5. verify_source() usage
...
if (is_present_hf("P-Request-Hash")) {
   if (verify_source()) {
      xlog("L_INFO", "Request came from trusted peer\n")
   }
}
...
