Reland of Verify sender ssrc when receiving rtcp target bitrate

webrtc/modules/rtp_rtcp/source/rtcp_receiver.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 670 matching lines @@
     ++num_skipped_packets_;
     return;
   }
 
   if (xr.rrtr())
     HandleXrReceiveReferenceTime(xr.sender_ssrc(), *xr.rrtr());
 
   for (const rtcp::ReceiveTimeInfo& time_info : xr.dlrr().sub_blocks())
     HandleXrDlrrReportBlock(time_info);
 
-  if (xr.target_bitrate())
-    HandleXrTargetBitrate(*xr.target_bitrate(), packet_information);
+  if (xr.target_bitrate()) {
+    HandleXrTargetBitrate(xr.sender_ssrc(), *xr.target_bitrate(),
+                          packet_information);
+  }
 }
 
 void RTCPReceiver::HandleXrReceiveReferenceTime(uint32_t sender_ssrc,
                                                 const rtcp::Rrtr& rrtr) {
   remote_time_info_.ssrc = sender_ssrc;
   remote_time_info_.last_rr = CompactNtp(rrtr.ntp());
   last_received_xr_ntp_ = clock_->CurrentNtpTime();
 }
 
 void RTCPReceiver::HandleXrDlrrReportBlock(const rtcp::ReceiveTimeInfo& rti) {
@@ skipping 12 matching lines @@
     return;
 
   uint32_t delay_ntp = rti.delay_since_last_rr;
   uint32_t now_ntp = CompactNtp(clock_->CurrentNtpTime());
 
   uint32_t rtt_ntp = now_ntp - delay_ntp - send_time_ntp;
   xr_rr_rtt_ms_ = CompactNtpRttToMs(rtt_ntp);
 }
 
 void RTCPReceiver::HandleXrTargetBitrate(
+    uint32_t ssrc,
     const rtcp::TargetBitrate& target_bitrate,
     PacketInformation* packet_information) {
+  if (ssrc != remote_ssrc_) {
+    return;  // Not for us.
+  }
+
   BitrateAllocation bitrate_allocation;
   for (const auto& item : target_bitrate.GetTargetBitrates()) {
     if (item.spatial_layer >= kMaxSpatialLayers ||
         item.temporal_layer >= kMaxTemporalStreams) {
       LOG(LS_WARNING)
           << "Invalid layer in XR target bitrate pack: spatial index "
           << item.spatial_layer << ", temporal index " << item.temporal_layer
           << ", dropping.";
     } else {
       bitrate_allocation.SetBitrate(item.spatial_layer, item.temporal_layer,
@@ skipping 297 matching lines @@
       } else {
         candidates.push_back(it->second.tmmbr_item);
         ++it;
       }
     }
   }
   return candidates;
 }
 
 }  // namespace webrtc