Hello,
On Friday 10 of February 2012 14:02:08 Daniel-Constantin Mierla wrote:
Hello,
On 2/9/12 5:13 PM, Andreas Granig wrote:
Hi,
I ran into a scenario with couple of serial forks where kamailio loops to itself and, due to the looping, the INVITE to a new branch happens before the CANCEL to an old branch. What I do at the moment is force rtpproxy in branch route, and stop rtpproxy in the failure route.
The problem with this scenario is that in rtpproxy_offer and unforce_rtpproxy, the rtpproxy module only passes the call-id and from-tag to rtpproxy (because there is no to-tag yet), which then in unforce_rtpproxy for a CANCEL deletes all calls related to it (because it can only match on from-tag and call-id, obviously). This means that when I do a subsequent rtpproxy_answer for my new branch, rtpproxy doesn't find the session anymore, since it has been removed with the CANCEL.
A fix I can think of is to also pass the branch of the top-most via to rtpproxy in order to perform a more fine-grained matching. Are there solutions to that out there somewhere, or is it something I should just introduce, eg. as a new param to offer/answer/unforce functions? Objections? Other approaches?
if you do rtpproxy handling on an instance that received a parallel forked call, then it is better to add the condition on top via branch, I don't see other solution for now and I am not aware of an implementation for it. I would add a new flag to rtpproxy parameters to send the branch value, that will allow to use old rptproxy versions when the flag is not given.
I've experienced similar problem with no-answer forwarding. In my scenario call was torn down from rtpproxy in onreply_route when "487 Request terminated" was received from B phone (upon CANCEL). I am using Kamailio 3.2 default configuration with rtpproxy_manage() and workaround is to check if transaction is canceled for negative replies in onreply_route and only then call rtpproxy_manage().
Can anybody think of scenario when this workaround will not clean up RTP proxy session?
I checked rtpproxy_manage function and patch should be really simple:
--- a/modules/rtpproxy/rtpproxy.c +++ b/modules/rtpproxy/rtpproxy.c @@ -1736,8 +1736,12 @@ rtpproxy_manage(struct sip_msg *msg, char *flags, char *ip) (ip!=NULL)?1:0); } } else if(msg->first_line.type == SIP_REPLY) { - if(msg->first_line.u.reply.statuscode>=300) + if(msg->first_line.u.reply.statuscode>=300) { + if(tmb.t_gett!=NULL && tmb.t_gett()!=NULL + && !(tmb.t_gett()->flags & T_CANCELED)) + return -1; return unforce_rtp_proxy_f(msg, 0, 0); + } if(nosdp==0) { if(tmb.t_gett==NULL || tmb.t_gett()==NULL || tmb.t_gett()==T_UNDEFINED)
Cheers, Jan