[SR-Users] How to increment dialog calee_cseq value when using t_uac_dlg via xmlrpc for generating INFO requests

Daniel-Constantin Mierla miconda at gmail.com
Tue Sep 9 16:32:43 CEST 2014


On 09/09/14 16:15, Drazen Rep wrote:
> Hi,
> I am using Kamailio 4.1.1 and dlg_manage() function for processing SIP 
> requests with dialog module. After call is established Kamailio is 
> being used for generating in-dialog INFO request toward caller (using 
> t_uac_dlg function via xmlrpc). INFO messages are correctly generated 
> but dialog calee_cseq value is not being incremented with every 
> message. That represents a problem since other SIP requests generated 
> by callee side (like OPTIONS) are not in order, and there is no 
> correct information about calee_cseq value in dialog memory records.
> The question is how can I increment dialog calee_cseq value when local 
> INFO request toward caller is being generated using t_uac_dlg via xmlrpc?
such feature is not available at this moment.

If the callee hasn't sent yet a message, the proxy won't have any clue 
on what is going to be initial cseq used by callee, because there is no 
constraint to start from 1 in the SIP RFC.

In the master branch (to become 4.2), I added recently support to 
increment the cseq towards caller, with the main target to handle 
authentication challenge from gateways/termination providers. In other 
words, dialog module has some capabilities towards handling cseq 
differences, but exactly what you need is not there.

To get that, probably a new rpc command has to be exported by dialog 
module, to catch cseq updates, because t_uac_dlg is from tm module, with 
no relation to dialog. So, overall, it is about writing some c code to 
dialog module -- as starting point you can look at dlg_cseq.{c,h} files 
to see how cseq can be updated and eventually at dlg_bridge rpc command 
to see how a request within dialog can be sent (it sends a REFER withing 
dialog) or dlg terminate (which sends BYE).

On the other hand, maybe there are other options for your needs, what is 
the purpose for INFO requests sent by the proxy?


Daniel-Constantin Mierla
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
Next Kamailio Advanced Trainings 2014 - http://www.asipto.com
Sep 22-25, Berlin, Germany

More information about the sr-users mailing list