From 478e9d7f47c371133ec1eb79b2e502eaf30397ff Mon Sep 17 00:00:00 2001
From: Thulinma <jaron@vietors.com>
Date: Tue, 31 Jan 2017 14:31:48 +0100
Subject: [PATCH] RTSP now uses ephemeral UDP ports instead of semi-random
 ports, preventing collisions

---
 src/output/output_rtsp.cpp |  5 ++++-
 src/output/output_rtsp.h   | 13 +++++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/src/output/output_rtsp.cpp b/src/output/output_rtsp.cpp
index 79284c4d..cf0022f9 100644
--- a/src/output/output_rtsp.cpp
+++ b/src/output/output_rtsp.cpp
@@ -437,7 +437,10 @@ namespace Mist {
     for (std::map<int, RTPTrack>::iterator it = tracks.begin(); it != tracks.end(); ++it){
       Socket::UDPConnection & s = it->second.data;
       while (s.Receive()){
-        if (s.getDestPort() != it->second.cPort){continue;}//port mismatch = skip
+        if (s.getDestPort() != it->second.cPort){
+          //wrong sending port, ignore packet
+          continue;
+        }
         RTP::Packet pack(s.data, s.data_len);
         if (!it->second.rtpSeq){it->second.rtpSeq = pack.getSequence();}
         //packet is very early - assume dropped after 10 packets
diff --git a/src/output/output_rtsp.h b/src/output/output_rtsp.h
index 7ec834af..5700ba8a 100644
--- a/src/output/output_rtsp.h
+++ b/src/output/output_rtsp.h
@@ -109,18 +109,23 @@ namespace Mist {
           channel = -1;
           size_t port_loc = transport.rfind("client_port=") + 12;
           cPort = atol(transport.substr(port_loc, transport.rfind('-') - port_loc).c_str());
-          unsigned int rand_offset = ((rand() % 4000) << 1) + 2000;
+          uint32_t portA, portB;
           //find available ports locally;
           int sendbuff = 4*1024*1024;
           data.SetDestination(host, cPort);
-          data.bind(rand_offset + trk.trackID * 2);
+          portA = data.bind(0);
           setsockopt(data.getSock(), SOL_SOCKET, SO_SNDBUF, &sendbuff, sizeof(sendbuff));
           rtcp.SetDestination(host, cPort + 1);
-          rtcp.bind(rand_offset + trk.trackID * 2 + 1);
+          portB = rtcp.bind(0);
           setsockopt(rtcp.getSock(), SOL_SOCKET, SO_SNDBUF, &sendbuff, sizeof(sendbuff));
           std::stringstream tStr;
-          tStr << "RTP/AVP/UDP;unicast;client_port=" << cPort << '-' << cPort + 1 << ";source="<< source <<";server_port=" << (rand_offset + trk.trackID * 2) << "-" << (rand_offset + trk.trackID * 2 + 1) << ";ssrc=" << std::hex << SSrc << std::dec;
+          tStr << "RTP/AVP/UDP;unicast;client_port=" << cPort << '-' << cPort + 1 << ";";
+          if (source.size()){
+            tStr << "source=" << source << ";";
+          }
+          tStr << "server_port=" << portA << "-" << portB << ";ssrc=" << std::hex << SSrc << std::dec;
           transportString = tStr.str();
+          INFO_MSG("Transport string: %s", transportString.c_str());
         }
         return true;
       }