[sr-dev] tcp problem

[Klaus Darilion]

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?

Go ahead :-)

regards
klaus