RTJSON Module

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Daniel-Constantin Mierla

   <miconda@gmail.com>

   Copyright © 2015 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. xavp_cfg (str)

        4. Functions

              4.1. rtjson_init_routes(rtdoc)
              4.2. rtjson_push_routes()
              4.3. rtjson_next_route()
              4.4. rtjson_update_branch()

        5. JSON Routing Structure

   List of Examples

   1.1. Set xavp_cfg parameter
   1.2. rtjson_init_routes usage
   1.3. rtjson_push_routes usage
   1.4. rtjson_next_route usage
   1.5. rtjson_update_branch usage
   1.6. JSON Routing Structure

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. xavp_cfg (str)

   4. Functions

        4.1. rtjson_init_routes(rtdoc)
        4.2. rtjson_push_routes()
        4.3. rtjson_next_route()
        4.4. rtjson_update_branch()

   5. JSON Routing Structure

1. Overview

   This module facilitates SIP routing based on JSON specifications.

   The values for R-URI ($ru), outbound proxy ($du) and other attributes
   used for SIP routing can be retrieved in a JSON document. It is able to
   process attributes for more than one destination and prepare for
   routing in serial or parallel fashion.

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:
     * tm - (optional) transaction management.
       uac - (optional) user agent operations.

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. xavp_cfg (str)

3.1. xavp_cfg (str)

   The name of the xavp to be used internally by the module.

   Default value is "rtjson".

   Example 1.1. Set xavp_cfg parameter
...
modparam("rtjson", "xavp_cfg", "myxavp")
...

4. Functions

   4.1. rtjson_init_routes(rtdoc)
   4.2. rtjson_push_routes()
   4.3. rtjson_next_route()
   4.4. rtjson_update_branch()

4.1.  rtjson_init_routes(rtdoc)

   Initialize routing based on JSON document stored in rtdoc parameter.

   The rtdoc parameter can be a static string or a dynamic string value
   with config variables. It has to result in a valid JSON document with
   the structure specified in chapter 'JSON Routing Structure'.

   This function can be used from REQUEST_ROUTE.

   Example 1.2. rtjson_init_routes usage
...
rtjson_init_routes("$var(json)");
...

4.2.  rtjson_push_routes()

   Push the routes given in JSON document to rtjson_init_routes(rtdoc) to
   the internal fields used by Kamailio for routing.

   This function can be used from REQUEST_ROUTE.

   Example 1.3. rtjson_push_routes usage
...
rtjson_init_routes("$var(json)");
rtjson_push_routes();
...

4.3.  rtjson_next_route()

   To be used in failure_route for serial forking, to push the next route
   to the internal fields used by Kamailio for routing.

   This function can be used from FAILURE_ROUTE.

   Example 1.4. rtjson_next_route usage
...
rtjson_init_routes("$var(json)");
rtjson_push_routes();
t_on_failure("REROUTE");
t_relay();
...
failure_route[REROUTE] {
        rtjson_next_route();
}
...

4.4.  rtjson_update_branch()

   To be used in branch_route if the JSON document had attributes that
   needs to be set for each branch.

   This function can be used from BRANCH_ROUTE.

   Example 1.5. rtjson_update_branch usage
...
rtjson_init_routes("$var(json)");
rtjson_push_routes();
t_on_branch("OUTGOING");
t_relay();
...
branch_route[OUTGOING] {
        rtjson_update_branch();
}
...

5. JSON Routing Structure

   The format of the JSON document containing routing information.

   Description of the fields in the JSON routing document:
     * version - intended to enforce versioning checks (not enforced yet),
       recommended to be set to "1.0".
     * routing - can be "serial" or "parallel", corresponding to desired
       routing type: serial or parallel forking.
     * routes - an array with structures holding the attributes for
       destinations. The attributes can be:
          + uri - request URI
          + dst_uri - outbound proxy URI
          + path - Path URI vector
          + socket - local socket
          + headers - a structure with values for headers From and To
            specified as display name and URI, plus extra headers to be
            appended to SIP request. It requires uac module in order to
            update From and To headers. Set by rtjson_update_branch() only
            for serial routing.
          + branch_flags - branch flags. Set by rtjson_update_branch()
            only for serial routing.
          + fr_timer - value for fr_timer parameter of tm module. Set by
            rtjson_update_branch() only for serial routing.
          + fr_inv_timer - value for fr_inv_timer parameter of tm module.
            Set by rtjson_update_branch() only for serial routing.

   Other fields can appear in the JSON routing document, being ignored by
   rtjson functions. They can be processed directly in the configuration
   files using json or jansson modules. For example, the document can
   include the transaction identification tuple (index,label) that can be
   used to resume the execution of a suspended transaction.

   Example 1.6. JSON Routing Structure
...
{
    "version": "1.0",
    "routing": "serial",
    "routes": [
        {
            "uri": "sip:bob@b.example.org:5060",
            "dst_uri": "sip:192.0.2.1:5060",
            "path": "<sip:192.0.2.2:5084>, <sip:192.0.2.2:5086>",
            "socket": "udp:192.0.2.20:5060",
            "headers": {
                "from": {
                    "display": "Alice",
                    "uri": "sip:alice@a.example.org"
                },
                "to": {
                    "display": "Bob",
                    "uri": "sip:bob@b.example.org"
                },
                "extra": "X-Hdr-A: abc\r\nX-Hdr-B: bcd\r\n"
            },
            "branch_flags": 8,
            "fr_timer": 5000,
            "fr_inv_timer": 30000
        },
        {
            "uri": "sip:bob@b.example.org:5060",
            "dst_uri": "sip:192.0.2.10:5060",
            "path": "<sip:192.0.2.2:5084>, <sip:192.0.2.2:5086>",
            "socket": "udp:192.0.2.20:5060",
            "headers": {
                "from": {
                    "display": "Alice",
                        "uri": "sip:alice@a.example.org"
                    },
                    "to": {
                        "display": "Bob",
                        "uri": "sip:bob@b.example.org"
                    },
                    "extra": "P-Asserted-Identity: <sip:alice@a.example.org>\r\n
"
            },
            "branch_flags": 8,
            "fr_timer": 5000,
            "fr_inv_timer": 30000
        },
    ]
}
...
