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.
Cheers, Daniel