[SR-Users] Hop by hop CANCEL, wrong to header

[Daniel-Constantin Mierla]

Hello,

On 5/23/12 5:22 PM, Vitaliy Aleksandrov wrote:
> Hi all,
>
> I have a question about CANCEL message processing.
>
> My call sceraio:
> When an INVITE request comes I need to rewrite a domain part of the 
> several headers(to, from, contact, SDP ip) according to the outgoing 
> interface.
> I can do it before t_relay(), but when destination user has more then 
> one locations and they are reachable through different interfaces all 
> forked INVITEs will have the same domain.
> To avoid that problem i have tried to move rewriting part(subst from 
> the textops module) to the branch_route.
>
> Unfortunately that solution didn't helped me, because "To" header of 
> the outgoing CANCEL messages is wrong (unchanged. as it was at the 
> moment when transaction was created by the t_relay() ).
> As i understood from the documentation and mailing list kamailio 
> builds CANCEL based on outgoing INVITE.
>
> I did a small research and found that Kamailio really takes outgoing 
> INVITE from each branch (invite_transaction_cell -> 
> uac[b_id].request.buffer) and builds CANCEL (build_local_reparse() 
> from tm/t_msgbuilder.c) based on it.
> But kamailio does an exception for the To header which is described below:
> ***cancel_branch* function (from t_cancel.c) calls 
> *build_local_reparse*() and fills one of the parameters with a pointer 
> to unmodified To header.
> *    build_local_reparse*() uses received To header to construct 
> outgoing CANCEL.
>
> I have changed:
>     cancel = build_local_reparse(t, branch, &len, CANCEL, CANCEL_LEN, 
> &t->to, reason);
> to:
>     cancel = build_local_reparse(t, branch, &len, CANCEL, CANCEL_LEN, 
> NULL, reason);
> and it works for me now.
>
> It looks like if E2E_CANCEL_HOP_BY_HOP *e2e_cancel()* (t_fwd.c) will 
> call *e2e_cancel_branch()* which works as i want instead of 
> *cancel_branch()*, but it is just my assumption.

do you mean if E2E_CANCEL_HOP_BY_HOP is defined? I quick grep at this 
time showed it is defined in t_fwd.h...

What is the version you are using?

Cheers,
Daniel

>
> Why does kamailio generate CANCEL requests in such a way ? Did i miss 
> something from the RFC3261 or kamailio documentation ?
>
> Thanks in advance for any help !
>
>
>
>
> _______________________________________________
> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
> sr-users at lists.sip-router.org
> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

-- 
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sip-router.org/pipermail/sr-users/attachments/20120525/17ffe51d/attachment.htm>