[SR-Users] Use RTPProxy in 302 scenario

[Fabian Borot]

I have this scenario

Customer --> Kamailio --> Provider1

The route where l route the call to Provider1 is called route["INCOMING"] and I "arm" the replies and failures to : t_on_reply("INCOMING") and t_on_failure("INCOMING").  Provider1 always replies with a 302 Redirect and in the failure_route["INCOMING'] I have this code:

        if (t_check_status("302")) {
                get_redirects("*");
                t_on_branch("REDIRECT_BRANCH");
                t_load_contacts();
                t_next_contacts();
                t_on_failure("SERIAL_FORKING");
                t_relay();
                exit;
        }

In the t_on_failure("SERIAL_FORKING") block I do t_relay() as long as there are more contacts to be processed. Lets say I need to try Provider_2 and Provider_3

failure_route["SERIAL_FORKING"]
{
        xlog("L_INFO","mylog: In Failure Route SERIAL_FORKING. Reply [$rs]\n");
        if (!t_next_contacts()) {
                exit;
        }
        xlog("L_INFO","mylog: In Failure Route SERIAL_FORKING. Trying next Contact.\n");
        t_on_failure("SERIAL_FORKING");
        t_relay();
}

I want to use RTPProxy in this scenario and I am using the function rtpproxy_manage() to let kamailio handle it automatically.  

		RTPProxy
		↑
		 |
		 |	
Customer --> Kamailio --> Provider1
		 |
		 |
		↓
		Provider N


After the 302 response is processed I would like to have the signaling flow "Customer -> Kamailio --> ProviderN" and the RTP flow "Customer --> RTPProxy --> ProviderN"

I have tried inserting the function in several places but can't make it work and what I mean is that sometimes the rtpproxy creates the 1st session and then deletes it as soon as I call it the 2nd time with a message similar to this one (log of rtpproxy) : "INFO:416f20b74a58fb75168175e61b2edece at 192.168.1.61:5060:rtpp_cmd_delete_ematch: forcefully deleting session 1 on ports 63502/0". Sometimes the kamailio log shows this message: "ERROR: rtpproxy [rtpproxy.c:2536]: force_rtp_proxy(): incorrect port 0 in reply from rtp proxy"

I think I must call rtpproxy_manage() before I send the INVITE to each of the Providers in the Contact list so they receive a SDP offer with an IP:Port combination provided by the RTPProxy (instead of the ones coming from the Customer). That would be in my route["INCOMING']
Then once Provider_N replies with a 183 with SDP or a 200 OK I would call it again to get a new session to be passed on the reply to my customer. But is the part I am struggling with. Should I add a new reply route inside the failure_route["INCOMING'] only if I am dealing with 302 and do it there ?
I am out of ideas guys and any idea is welcome