prefix_route Module

Alfred E. Heggestad

   Telio Telecom

   Copyright © 2007 Alfred E. Heggestad

   Copyright © 2008 Telio Telecom AS
     __________________________________________________________________

   List of Examples

   1. Setting db_url parameter
   2. Setting db_table parameter
   3. Setting exit parameter
   4. prefix_route() usage
   5. Sample data

1. Overview

   The prefix_route module does routing based on a set of prefixes from
   the database. The prefix rule-set is loaded from the database into a
   binary tree in memory, either on startup or when issuing the
   "prefix_route.reload" RPC command. When calling the "prefix_route()"
   function from the ser.cfg configuration script, it will try to match
   the user part of the request URI with the best matching route. If a
   route is found, it will be used for further processing. If not found
   normal processing will continue.

   Development was sponsored by Telio Telecom.

2. Parameters

   2.1. db_url (string)
   2.2. db_table (string)
   2.3. exit (int)

2.1. db_url (string)

   This is URL of the database to be used.

   Default value is "mysql://ser@localhost/ser"

   Example 1. Setting db_url parameter
...
modparam("prefix_route", "db_url", "mysql://ser:pass@db_host/ser")
...

2.2. db_table (string)

   The name of table where to read prefix route set.

   Default value is "prefix_route".

   Example 2. Setting db_table parameter
...
modparam("prefix_route", "db_table", "new_prefix_route")
...

2.3. exit (int)

   If set, exit the execution of the configuration file when a route block
   is executed upon matching a prefix. Otherwise return 1 (true).

   Default value is 1 (on).

   Example 3. Setting exit parameter
...
modparam("prefix_route", "exit", 0)
...

3. Functions

   3.1. prefix_route([user])

3.1. prefix_route([user])

   This function tries to find a route from the user part of the request
   URI (if no parameter is provided), or from the value of the parameter.
   The parameter can contain config variables.

   If a route is found, it will be used for further processing. Otherwise
   the function will return false.

   Example 4. prefix_route() usage
...
  if (!prefix_route()) {
      xlog("L_ERR", "prefix_route(): no matching routes\n");
  }
...
  if (!prefix_route("$fU")) {
      xlog("L_ERR", "prefix_route(): no matching routes\n");
  }

...

4. RPC Commands

   4.1. prefix_route.reload
   4.2. prefix_route.dump

4.1. prefix_route.reload

   Reload prefix route tree from the database. Validation is done and the
   prefix route tree will only be reloaded if there are no errors.

4.2. prefix_route.dump

   Dump the current prefix route tree.

5. Database Structure

   A prefix route set consists of three fields:
     * prefix - varchar(64) - Prefix rule
     * route - varchar(64) - Route name
     * comment - varchar(64) - Free-form comment

   Example 5. Sample data
...
   +--------+-------+---------------+
   | prefix | route | comment       |
   +--------+-------+---------------+
   | 46     | SE    | Sweden        |
   | 47     | NO    | Norway        |
   | 479    | NOMOB | Norway mobile |
   | 49     | DE    | Deutschland   |
   | 39     | IT    | Italy         |
   +--------+-------+---------------+
...
