Table of Contents
List of Examples
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 ...
The default port to be used by all WebSocket listeners.
Default value is 80.
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.
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.