Options Module

Nils Ohlmeier

   FhG Fokus

Edited by

Nils Ohlmeier

   Copyright © 2003 FhG Fokus
   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. accept (string)
              1.3.2. accept_encoding (string)
              1.3.3. accept_language (string)
              1.3.4. support (string)

        1.4. Exported Functions

              1.4.1. options_reply()

   List of Examples

   1.1. Set accept parameter
   1.2. Set accept_encoding parameter
   1.3. Set accept_language parameter
   1.4. Set support parameter
   1.5. options_reply usage

Chapter 1. Admin Guide

1.1. Overview

   This module provides a function to answer OPTIONS requests
   which are directed to the server itself. This means an OPTIONS
   request which has the address of the server in the request URI,
   and no username in the URI. The request will be answered with a
   200 OK which the capabilities of the server.

   To answer OPTIONS request directed to your server is the
   easiest way for is-alive-tests on the SIP (application) layer
   from remote (similar to ICMP echo requests, also known as
   "ping", on the network layer).

1.2. Dependencies

1.2.1. OpenSIPS Modules

   The following modules must be loaded before this module:
     * sl -- Stateless replies.

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. accept (string)

   This parameter is the content of the Accept header field. Note:
   it is not clearly written in RFC3261 if a proxy should accept
   any content (the default "*/*") because it does not care about
   content. Or if it does not accept any content, which is "".

   Default value is "*/*".

   Example 1.1. Set accept parameter
...
modparam("options", "accept", "application/*")
...

1.3.2. accept_encoding (string)

   This parameter is the content of the Accept-Encoding header
   field. Please do not change the default value because OpenSIPS
   does not support any encodings yet.

   Default value is "".

   Example 1.2. Set accept_encoding parameter
...
modparam("options", "accept_encoding", "gzip")
...

1.3.3. accept_language (string)

   This parameter is the content of the Accept-Language header
   field. You can set any language code which you prefer for error
   descriptions from other devices, but presumably there are not
   much devices around which support other languages then the
   default English.

   Default value is "en".

   Example 1.3. Set accept_language parameter
...
modparam("options", "accept_language", "de")
...

1.3.4. support (string)

   This parameter is the content of the Support header field.
   Please do not change the default value, because OpenSIPS
   currently does not support any of the SIP extensions registered
   at the IANA.

   Default value is "".

   Example 1.4. Set support parameter
...
modparam("options", "support", "100rel")
...

1.4. Exported Functions

1.4.1.  options_reply()

   This function checks if the request method is OPTIONS and if
   the request URI does not contain an username. If both is true
   the request will be answered stateless with "200 OK" and the
   capabilities from the modules parameters.

   It sends "500 Server Internal Error" for some errors and
   returns false if it is called for a wrong request.

   The check for the request method and the missing username is
   optional because it is also done by the function itself. But
   you should not call this function outside the myself check
   because in this case the function could answer OPTIONS requests
   which are sent to you as outbound proxy but with an other
   destination then your proxy (this check is currently missing in
   the function).

   This function can be used from REQUEST_ROUTE.

   Example 1.5. options_reply usage
...
if (uri==myself) {
        if ((method==OPTIONS) && (! uri=~"sip:.*[@]+.*")) {
                options_reply();
        }
}
...