proto_ws Module

OpenSIPS Project

Edited by

Razvan Crainea

   Copyright © 2015 OpenSIPS Project
     __________________________________________________________

   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. ws_port (integer)
              1.3.2. ws_send_timeout (integer)
              1.3.3. ws_max_msg_chunks (integer)

   2. Frequently Asked Questions

   List of Examples

   1.1. Set ws_port parameter
   1.2. Set ws_send_timeout parameter
   1.3. Set ws_max_msg_chunks parameter

Chapter 1. Admin Guide

1.1. Overview

   The WebSocket protocol (RFC 6455) provides an end-to-end
   full-duplex communication channel between two web-based
   applications. This allows WebSocket enabled browsers to connect
   to a WebSocket server and exchange any type of data. RFC 7118
   provides the specifications for transporting SIP messages over
   the WebSocket protocol.

   The proto_ws module is transport module that provides
   communication over the WebSocket protocol. This module is fully
   compliant with the RFC 7118, thus allowing browsers to act as
   SIP clients for the OpenSIPS proxy.

   The current implementation can only act as a WebSocket server,
   meaning that it can only accept connections from WebSocket
   clients and cannot initiate connections to another WebSocket
   server. After the connection is established, messages can flow
   in both directions.

   OpenSIPS supports the following WebSocket operations:
     * text and binary - can both send and receive WebSocket
       messages that contain text or binary body
     * close - messages used to safely close the WebSocket
       communication using a 2-messages handshake
     * ping - responds with pong messages. There is no mechanism
       to trigger ping messages.
     * pong - sent when a ping message is received. OpenSIPS,
       absorbes the pong messages received.

   Once loaded, you will be able to define WebSocket listeners in
   your script. To add a listener, you have to add its IP, and
   optionally the listening port, after the mpath parameter,
   similar to this example:

...
mpath=/path/to/modules
...
listen=ws:127.0.0.1             # change with the listening IP
listen=ws:127.0.0.1:5060        # change with the listening IP and port
...

1.2. Dependencies

1.2.1. OpenSIPS Modules

   The following modules must be loaded before this module:
     * None.

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. ws_port (integer)

   The default port to be used by all WebSocket listeners.

   Default value is 80.

   Example 1.1. Set ws_port parameter
...
modparam("proto_ws", "ws_port", 8080)
...

1.3.2. ws_send_timeout (integer)

   Time in milliseconds after a WebSocket connection will be
   closed if it is not available for blocking writing in this
   interval (and OpenSIPS wants to send something on it).

   Default value is 100 ms.

   Example 1.2. Set ws_send_timeout parameter
...
modparam("proto_ws", "ws_send_timeout", 200)
...

1.3.3. ws_max_msg_chunks (integer)

   The maximum number of chunks that a SIP message is expected to
   arrive via WebSocket. If a packet is received more fragmented
   than this, the connection is dropped (either the connection is
   very overloaded and this leads to high fragmentation - or we
   are the victim of an ongoing attack where the attacker is
   sending the traffic very fragmented in order to decrease our
   performance).

   Default value is 4.

   Example 1.3. Set ws_max_msg_chunks parameter
...
modparam("proto_ws", "ws_max_msg_chunks", 8)
...

Chapter 2. Frequently Asked Questions

   2.1.

       Can OpenSIPS act as a WebSocket client?

       No, currently OpenSIPS can only behave as a Websocket server.

   2.2.

       Does OpenSIPS support WebSocket message fragmentation?

       No, WebSocket fragmentation mechanims is not supported.
