Domain Module

Juha Heinanen

   <jh@tutpro.com>

Edited by

Juha Heinanen

   <jh@tutpro.com>

   Copyright © 2002-2008 Juha Heinanen
   Revision History
   Revision $Revision: 4630 $ $Date: 2008-03-08 00:03:56 +0100
                              (Sa, 08 MÃ¤r 2008) $
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Dependencies
        1.3. Exported Parameters

              1.3.1. db_url (string)
              1.3.2. db_mode (integer)
              1.3.3. domain_table (string)
              1.3.4. domain_col (string)

        1.4. Exported Functions

              1.4.1. is_from_local()
              1.4.2. is_uri_host_local()
              1.4.3. is_domain_local(pseudo_variable)

        1.5. Exported MI Functions

              1.5.1. domain_reload
              1.5.2. domain_dump

        1.6. Known Limitations

   2. Developer Guide

        2.1. Available Functions

              2.1.1. is_domain_local(domain)

   List of Examples

   1.1. Setting db_url parameter
   1.2. db_mode example
   1.3. Setting domain_table parameter
   1.4. Setting domain_col parameter
   1.5. is_from_local usage
   1.6. is_uri_host_local usage
   1.7. is_domain_local usage

Chapter 1. Admin Guide

1.1. Overview

   Domain module implements checks that based on domain table
   determine if a host part of an URI is "local" or not. A "local"
   domain is one that the proxy is responsible for.

   Domain module operates in caching or non-caching mode depending
   on value of module parameter db_mode. In caching mode domain
   module reads the contents of domain table into cache memory
   when the module is loaded. After that domain table is re-read
   only when module is given domain_reload fifo command. Any
   changes in domain table must thus be followed by
   "domain_reload" command in order to reflect them in module
   behavior. In non-caching mode domain module always queries
   domain table in the database.

   Caching is implemented using a hash table. The size of the hash
   table is given by HASH_SIZE constant defined in domain_mod.h.
   Its "factory default" value is 128.

1.2. Dependencies

   The module depends on the following modules (in the other words
   the listed modules must be loaded before this module):
     * database -- Any database module

1.3. Exported Parameters

1.3.1. db_url (string)

   This is URL of the database to be used.

   Default value is
   "mysql://openserro:openserro@localhost/openser"

   Example 1.1. Setting db_url parameter
modparam("domain", "db_url", "mysql://ser:pass@db_host/ser")

1.3.2. db_mode (integer)

   Database mode: 0 means non-caching, 1 means caching.

   Default value is 0 (non-caching).

   Example 1.2. db_mode example
modparam("domain", "db_mode", 1)   # Use caching

1.3.3. domain_table (string)

   Name of table containing names of local domains that the proxy
   is responsible for. Local users must have in their sip uri a
   host part that is equal to one of these domains.

   Default value is "domain".

   Example 1.3. Setting domain_table parameter
modparam("domain", "domain_table", "new_name")

1.3.4. domain_col (string)

   Name of column containing domains in domain table.

   Default value is "domain".

   Example 1.4. Setting domain_col parameter
modparam("domain", "domain_col", "domain_name")

1.4. Exported Functions

1.4.1. is_from_local()

   Checks based on domain table if host part of From header uri is
   one of the local domains that the proxy is responsible for

   This function can be used from REQUEST_ROUTE.

   Example 1.5. is_from_local usage
...
if (is_from_local()) {
        ...
};
...

1.4.2. is_uri_host_local()

   If called from route or failure route block, checks based on
   domain table if host part of Request-URI is one of the local
   domains that the proxy is responsible for. If called from
   branch route, the test is made on host part of URI of first
   branch, which thus must have been appended to the transaction
   before is_uri_host_local() is called.

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE.

   Example 1.6. is_uri_host_local usage
...
if (is_uri_host_local()) {
        ...
};
...

1.4.3. is_domain_local(pseudo_variable)

   This function checks if the domain contained in the
   pseudo_variable is local.

   This function is a generalized form of the is_from_local() and
   is_uri_host_local() functions, being able to completely replace
   them and also extends them by allowing the domain to be taken
   from any of the above mentioned sources. The following
   equivalences exist:
     * is_domain_local("$rd") is same as is_uri_host_local()
     * is_domain_local("$fd") is same as is_from_local()

   This function can be used from REQUEST_ROUTE, FAILURE_ROUTE,
   BRANCH_ROUTE.

   Example 1.7. is_domain_local usage
...
if (is_domain_local("$rd")) {
        ...
};
if (is_domain_local("$fd")) {
        ...
};
if (is_domain_local("$avp(some_avp_alias)")) {
        ...
};
if (is_domain_local("$avp(i:850)")) {
        ...
};
if (is_domain_local("$avp(s:some_avp)")) {
        ...
};
...

1.5. Exported MI Functions

1.5.1. domain_reload

   Causes domain module to re-read the contents of domain table
   into cache memory.

   Name: domain_reload

   Parameters: none

   MI FIFO Command Format:
                :domain_reload:_reply_fifo_file_
                _empty_line_

1.5.2. domain_dump

   Causes domain module to dump hash indexes and domain names in
   its cache memory.

   Name: domain_dump

   Parameters: none

   MI FIFO Command Format:
                :domain_dump:_reply_fifo_file_
                _empty_line_

1.6. Known Limitations

   There is an unlikely race condition on domain list update. If a
   process uses a table, which is reloaded at the same time twice
   through FIFO, the second reload will delete the original table
   still in use by the process.

Chapter 2. Developer Guide

   The module provides is_domain_local API function for use by
   other Kamailio modules.

2.1. Available Functions

2.1.1.  is_domain_local(domain)

   Checks if domain given in str* parameter is local.

   The function returns 1 if domain is local and -1 if domain is
   not local or if an error occurred.
