From 0a554938d0af4f72857d68578e9f7fd620fc91a7 Mon Sep 17 00:00:00 2001
From: Heikki Tampio <heikki.tampio@tuni.fi>
Date: Wed, 19 Apr 2023 12:47:36 +0300
Subject: [PATCH] multiplex: Add option to manually set remote SSRC of media
 stream

---
 include/uvgrtp/media_stream.hh |  1 +
 include/uvgrtp/util.hh         | 12 +++++++++---
 src/media_stream.cc            | 10 +++++++++-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/include/uvgrtp/media_stream.hh b/include/uvgrtp/media_stream.hh
index c11bfc1..49242e1 100644
--- a/include/uvgrtp/media_stream.hh
+++ b/include/uvgrtp/media_stream.hh
@@ -422,6 +422,7 @@ namespace uvgrtp {
             ssize_t fps_denominator_ = 1;
             uint32_t bandwidth_ = 0;
             std::shared_ptr<std::atomic<std::uint32_t>> ssrc_;
+            std::shared_ptr<std::atomic<std::uint32_t>> remote_ssrc_;
     };
 }
 
diff --git a/include/uvgrtp/util.hh b/include/uvgrtp/util.hh
index 8c11ce4..36122bf 100644
--- a/include/uvgrtp/util.hh
+++ b/include/uvgrtp/util.hh
@@ -363,12 +363,18 @@ enum RTP_CTX_CONFIGURATION_FLAGS {
      */
     RCC_FPS_DENOMINATOR  = 9,
 
-    /** Set the SSRC of the stream manually
+    /** Set the local SSRC of the stream manually
     *
-    * By default SSRC is generated randomly
+    * By default local SSRC is generated randomly
     */
     RCC_SSRC = 10,
 
+    /** Set the remote SSRC of the stream manually
+    *
+    * By default remote SSRC is generated randomly
+    */
+    RCC_REMOTE_SSRC = 11,
+
     /** Set bandwidth for the session
     * 
     * uvgRTP chooses this automatically depending on the format of the data being transferred.
@@ -381,7 +387,7 @@ enum RTP_CTX_CONFIGURATION_FLAGS {
     * Larger bandwidth values result in shorter RTCP intervals, and vice versa.
     * See RFC 3550 Appendix A.7 for further information on RTCP interval
     */
-    RCC_SESSION_BANDWIDTH = 11,
+    RCC_SESSION_BANDWIDTH = 12,
 
     /// \cond DO_NOT_DOCUMENT
     RCC_LAST
diff --git a/src/media_stream.cc b/src/media_stream.cc
index bbe5210..818d764 100644
--- a/src/media_stream.cc
+++ b/src/media_stream.cc
@@ -58,7 +58,8 @@ uvgrtp::media_stream::media_stream(std::string cname, std::string remote_addr,
     cname_(cname),
     fps_numerator_(30),
     fps_denominator_(1),
-    ssrc_(std::make_shared<std::atomic<std::uint32_t>>(uvgrtp::random::generate_32()))
+    ssrc_(std::make_shared<std::atomic<std::uint32_t>>(uvgrtp::random::generate_32())),
+    remote_ssrc_(std::make_shared<std::atomic<std::uint32_t>>(uvgrtp::random::generate_32()))
 {
     //socket_ = sfp_->create_new_socket();
     //holepuncher_ = std::unique_ptr<uvgrtp::holepuncher>(new uvgrtp::holepuncher(socket_));
@@ -768,6 +769,13 @@ rtp_error_t uvgrtp::media_stream::configure_ctx(int rcc_flag, ssize_t value)
             *ssrc_ = (uint32_t)value;
             break;
         }
+        case RCC_REMOTE_SSRC: {
+            if (value <= 0 || value > (ssize_t)UINT32_MAX)
+                return RTP_INVALID_VALUE;
+
+            *remote_ssrc_ = (uint32_t)value;
+            break;
+        }
         default:
             return RTP_INVALID_VALUE;
     }