[sr-dev] tcp problem

[Andrei Pelinescu-Onciul]

On Nov 02, 2009 at 08:19, Klaus Darilion <klaus.mailinglists at pernau.at> wrote:
> 
> 
> Andrei Pelinescu-Onciul schrieb:
> >On Oct 30, 2009 at 15:15, Klaus Darilion <klaus.mailinglists at pernau.at> 
> >wrote:
> >>
> >>Andrei Pelinescu-Onciul schrieb:
> >>>On Oct 29, 2009 at 08:16, Klaus Darilion <klaus.mailinglists at pernau.at> 
> >>>wrote:
> >>>>Long time ago, ser always used the OS default interface for new TCP 
> >>>>connections. In Openser this was changed to the first listening TCP 
> >>>>address, and further could be specified by force_send_socket.
> >>>>
> >>>>I know there were some changes in ser/sr too, but do not know exactly 
> >>>>what was changed.
> >>>In ser/sr the default ip for outgoing TCP connections can be forced
> >>>using:
> >>>tcp_source_ipv4="ip" and 
> >>>tcp_source_ipv6="ip".
> >>>
> >>>By default the OS chooses the src ip (e.g. according to the routing
> >>>table) and ser/sr tries to match with the list of IPs it is listening
> >>>on. The default behaviour along with either listening on all the IPs or
> >>>making sure your routing table uses the src ip you want, it's more error
> >>>proof (automatic multi-homing) and a little bit faster (avoids an extra
> >>>bind()).
> >>>
> >>>I could add a config option to always use the msg send_socket, but what
> >>>would probably be best would be to force a src_ip only if a send_socket
> >>>was forced and if not use the OS one or tcp_source_ipv4 if set.
> >>This is IMO a good option - I guess this also would allow usage of 
> >>force_send_socket, e.g. force_send_socket("tcp:1.2.3.4").
> >>
> >>btw: does this imply that the current documentation (copied from 
> >>Kamailio) is wrong as it does not work with outgoing TCP messages?
> >>http://sip-router.org/wiki/cookbooks/core-cookbook/devel#force_send_socket
> >>
> >
> >The via, rr a.s.o will use the information in the force_socket, however
> >the src_ip of the tcp connection is independent of it.
> >
> >
> >I can add the force_send_socket() sets src. for tcp new connection
> >feature quite easily, the question is whether or not to do it on sr_3.0.
> 
> IMO choosing the src-IP dynamically is an important feature. But 
> probably others have to decide if it can make it into 3.0.
> 
> >One difference from k would be that in k (and older ser) a connection
> >from IP1->X is equivalent to IP2->x (only the destination is used, if
> >for example you do force_send_socket(IP2); forward...(X) and a connection
> >from IP1 -> X already exists, this connection will be used and no new
> >connection will be created) while in sr the connections will be
> >different (both the source and the destinations are used => in the above
> >example a new IP2 -> X connection will be opened even if IP1 -> X
> >already exists which IMHO is the correct thing to do).
> 
> So, it is not implemented yet, but if you would implement it, then both 
> (source+dst) will be used as connection identifier?

Yes and it is already implemented (tcp_send takes both a from and a to),
but it's not activated.

> 
> Go ahead :-)
> 

Andrei