Hello,

On 6/22/12 11:13 AM, Peter Dunkley wrote:

Hi,

I am just trying to work out exactly what needs to be updated in the Kamailio core/parser for WebSockets.

I already know that the Via: parser needs to be updated to understand the WS and WSS transports, and the URI parser needs to be updated to understand the the WS transport, but is there anything else?

I'd appreciate it if anyone has any ideas about what else might need changed (and where in the code), as my guessing at this could be a bit hit-and-miss...

indeed it might be hard to hit all at once, but it can be fixed as it goes on...

I don't plan to add a forward_ws() function to core because I don't think it'll work (or at least not in all cases as servers cannot initiate WebSocket connections). But are there updates needed in the following areas (and any ideas where in the code I should look)?

forward_no_connect()

the proto core variable

the snd_proto core variable

these are part of configuration file language, as special tokens -- the grammar of the config file is handled in cfg.lex and cfg.y. Then the interpretation is in action.c, with fixup and helpers in route_struct.{c,h} and route.{c,h}, and it may go through other files. I can help with flex/yacc part if needed.

Is a WS keyword (like SCTP/TCP/TLS/UDP) needed

Yes, IMO, useful for detecting the incoming protocol

Are the pseudo variables (for example, I know that the mutable variable $du needs to do the right thing as this is fundamental to being able to route requests), transformations, and selects that need to be updated

The $du is practically just returning/setting a string, the interpretation is done by internal relay/forward functions. There are some pv/selects that return the protocol, they need updates, but should be trivial once the core part of defining the protocol types (e.g., like PROTO_WS/PROTO_WSS) and updating the uri parser and socket structures.

Btw, there will be dedicated sockets to listen for ws/wss or the tcp/tls will be used and the connection type upgraded to ws/wss?

Are there any modules (rr, nathelper?) that need to be updated

There should be some helper functions that build URIs based on internal structures, where the protocol is used. Not sure all the modules use them or have own implementation. Perhaps searching on PROTO_TLS or another one will reveal the places where to add PROTO_WS/_WSS

Cheers,
Daniel

-- 
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Kamailio Advanced Training, Seattle, USA, Sep 23-26, 2012 - http://asipto.com/u/katu
Kamailio Practical Workshop, Netherlands, Sep 10-12, 2012 - http://asipto.com/u/kpw