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 !
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