
Options Module

Nils Ohlmeier

   FhG Fokus

Edited by

Nils Ohlmeier

   Copyright © 2003 FhG Fokus
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   Table of Contents
   1. User's Guide

        1.1. Overview
        1.2. Dependencies

              1.2.1. OpenSER 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()

   2. Developer's Guide
   3. Frequently Asked Questions

   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
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Chapter 1. User's 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).
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1.2. Dependencies

1.2.1. OpenSER Modules

   The following modules must be loaded before this module:

     * sl -- Stateless replies.
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1.2.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSER with this module loaded:

     * None.
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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/*")
...
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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 OpenSER
   does not support any encodings yet.

   Default value is "". 

   Example 1-2. Set accept_encoding parameter
...
modparam("options", "accept_encoding", "gzip")
...
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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")
...
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1.3.4. support (string)

   This parameter is the content of the Support header field.
   Please do not change the default value, because OpenSER
   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")
...
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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();
        }
}
...
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Chapter 2. Developer's Guide

   The module does not provide any API to use in other OpenSER
   modules.
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Chapter 3. Frequently Asked Questions

   3.1. Where can I find more about OpenSER?
   3.2. Where can I post a question about this module?
   3.3. How can I report a bug?

   3.1. Where can I find more about OpenSER?

   Take a look at http://openser.org/.

   3.2. Where can I post a question about this module?

   First at all check if your question was already answered on
   one of our mailing lists:

     * User Mailing List -
       http://openser.org/cgi-bin/mailman/listinfo/users
     * Developer Mailing List -
       http://openser.org/cgi-bin/mailman/listinfo/devel

   E-mails regarding any stable OpenSER release should be sent to
   <users@openser.org> and e-mails regarding development versions
   should be sent to <devel@openser.org>.

   If you want to keep the mail private, send it to
   <team@openser.org>.

   3.3. How can I report a bug?

   Please follow the guidelines provided at:
   http://openser.org/bugs.
