---
title: "proto_ws Module"
description: "The WebSocket protocol ([RFC 6455](http://tools.ietf.org/html/rfc6455)) provides an end-to-end full-duplex communication channel between two web-based applications."
---

## Admin Guide


### Overview


The WebSocket protocol ([RFC 6455](http://tools.ietf.org/html/rfc6455))
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](http://tools.ietf.org/html/rfc7118)
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](http://tools.ietf.org/html/rfc7118), thus allowing browsers
to act as SIP clients for the OpenSIPS proxy.


The current implementation acts both as WebSocket server and client, thus it can
accept connections from WebSocket clients and can also 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:

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


### Dependencies


#### OpenSIPS Modules


The following modules must be loaded before this module:


- *None*.


#### External Libraries or Applications


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


- *None*.


### Exported Parameters


#### ws_port (integer)


The default port to be used for all WS related operation. Be careful
as the default port impacts both the SIP listening part (if no port is
defined in the WS listeners) and the SIP sending part (if the 
destination WS URI has no explicit port).


If you want to change only the listening port for WS, use the port
option in the SIP listener defintion.


*Default value is 80.*


```c title="Set ws_port parameter"
...
modparam("proto_ws", "ws_port", 8080)
...
```


#### 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.*


```opensips title="Set ws_send_timeout parameter"
...
modparam("proto_ws", "ws_send_timeout", 200)
...
```


#### ws_max_msg_chunks (integer)


The maximum number of chunks in which a SIP message is expected to
arrive via WebSocket. If a received packet is 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 very
fragmented traffic in order to decrease server performance).


*Default value is 4.*


```opensips title="Set ws_max_msg_chunks parameter"
...
modparam("proto_ws", "ws_max_msg_chunks", 8)
...
```


#### trace_destination (string)


Trace destination as defined in the tracing module. Currently
the only tracing module is **proto_hep**.
Network events such as connect, accept and connection closed events
shall be traced along with errors that could appear in the process.
For each connection that is created an event containing information
about http request and reply belonging to  web socket protocol
handshake and network layer information shall be sent.


> [!WARNING]
> A tracing module must be
> loaded in order for this parameter to work. (for example
> **proto_hep**).


*Default value is none(not defined).*


```opensips title="Set trace_destination parameter"
...
modparam("proto_hep", "hep_id", "[hep_dest]10.0.0.2;transport=tcp;version=3")

modparam("proto_ws", "trace_destination", "hep_dest")
...
```


#### trace_on (int)


This controls whether tracing for ws is on or not. You still need to define
[trace destination](#trace_destination-string)in order to work, but this value will be
controlled using mi function [mi trace](#wstrace).


```opensips title="Set trace_on parameter"
...
modparam("proto_ws", "trace_on", 1)
...
```


#### trace_filter_route (string)


Define the name of a route in which you can filter which connections will
be trace and which connections won't be. In this route you will have
information regarding source and destination ips and ports for the current
connection. To disable tracing for a specific connection the last call in
this route must be **drop**, any other exit
mode resulting in tracing the current connection ( of course you still
have to define a [trace destination](#trace_destination-string) and trace must be
on at the time this connection is opened.


> [!IMPORTANT]
> Filtering on ip addresses and ports can be made using **$si** and **$sp** for matching
> either the entity that is connecting to OpenSIPS or the entity to which
> OpenSIPS is connecting. The name might be misleading (**$si** meaning the source ip if you read the docs) but in reality
> it is simply the socket other than the OpenSIPS socket. In order to match
> OpenSIPS interface (either the one that accepted the connection or the one
> that initiated a connection) **$socket_in(ip)** (ip) and
> **$socket_in(port)** (port) can be used.


> [!WARNING]
> If [trace on](#trace_on-int) is
> set to 0 or tracing is deactived via the mi command [mi trace](#wstrace)
> this route won't be called.


```opensips title="Set trace_filter_route parameter"
...
modparam("proto_ws", "trace_filter_route", "ws_filter")
...
/* all ws connections will go through this route if tracing is activated
 * and a trace destination is defined */
route[ws_filter] {
	...
	/* all connections opened from/by ip 1.1.1.1:8000 will be traced
	   on interface 1.1.1.10:5060(opensips listener)
	   all the other connections won't be */
	 if ( $si == "1.1.1.1" && $sp == 8000 &&
		$socket_in(ip) == "1.1.1.10"  && $socket_in(port) == 5060)
		exit;
	else
		drop;
}
...
```


#### require_origin (int)


Controls whether the module should require the Origin header or not.


```opensips title="Set require_origin parameter"
...
modparam("proto_ws", "require_origin", no)
...
```


### Exported MI Functions


#### ws:trace


Replaces obsolete MI command: *ws_trace*.


Name: *ws:trace*


Parameters:


- trace_mode(optional): set ws tracing on and off. This parameter
can be missing and the command will show the current tracing
status for this module( on or off );
Possible values:
	- on
	- off


MI FIFO Command Format:


```bash
opensips-cli -x mi ws:trace on
```


## Frequently Asked Questions


**Q: Can OpenSIPS act as a WebSocket client?**


Yes, starting with OpenSIPS 2.2, it can act as a WebSocket client.


**Q: Does OpenSIPS support WebSocket message fragmentation?**


No, WebSocket fragmentation mechanism is not supported.
<!-- CONTRIBUTORS -->

### License

All documentation files (i.e. .md extension) are licensed under the Creative Common License 4.0
