22 Jun
2012
22 Jun
'12
1:14 p.m.
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