Move RTP/RTCP demuxing logic from BaseChannel to RtpTransport.

webrtc/pc/channel.cc

Index: webrtc/pc/channel.cc
diff --git a/webrtc/pc/channel.cc b/webrtc/pc/channel.cc
index f5428a43effac7a93fce554e11946c220946337c..a08d7ae35091b7b78d2e29a758b5ff5d50407463 100644
--- a/webrtc/pc/channel.cc
+++ b/webrtc/pc/channel.cc
@@ -105,15 +105,9 @@ struct DataChannelErrorMessageData : public rtc::MessageData {
   DataMediaChannel::Error error;
 };
 
-static const char* PacketType(bool rtcp) {
-  return (!rtcp) ? "RTP" : "RTCP";
-}
-
 static bool ValidPacket(bool rtcp, const rtc::CopyOnWriteBuffer* packet) {
   // Check the packet size. We could check the header too if needed.
-  return (packet &&
-          packet->size() >= (!rtcp ? kMinRtpPacketLen : kMinRtcpPacketLen) &&
-          packet->size() <= kMaxRtpPacketLen);
+  return packet && IsValidRtpRtcpPacketSize(rtcp, packet->size());
 }
 
 static bool IsReceiveContentDirection(MediaContentDirection direction) {
@@ -179,6 +173,11 @@ BaseChannel::BaseChannel(rtc::Thread* worker_thread,
 #endif
   rtp_transport_.SignalReadyToSend.connect(
       this, &BaseChannel::OnTransportReadyToSend);
+  // TODO(zstein):  RtpTransport::SignalPacketReceived will probably be replaced
+  // with a callback interface later so that the demuxer can select which
+  // channel to signal.
+  rtp_transport_.SignalPacketReceived.connect(this,
+                                              &BaseChannel::OnPacketReceived);
   LOG(LS_INFO) << "Created channel for " << content_name;
 }
 
@@ -214,6 +213,9 @@ void BaseChannel::DisconnectTransportChannels_n() {
     DisconnectFromPacketTransport(rtp_transport_.rtcp_packet_transport());
   }
 
+  rtp_transport_.SetRtpPacketTransport(nullptr);
+  rtp_transport_.SetRtcpPacketTransport(nullptr);
+
   // Clear pending read packets/messages.
   network_thread_->Clear(&invoker_);
   network_thread_->Clear(this);
@@ -397,7 +399,6 @@ void BaseChannel::ConnectToDtlsTransport(DtlsTransportInternal* transport) {
 
   // TODO(zstein): de-dup with ConnectToPacketTransport
   transport->SignalWritableState.connect(this, &BaseChannel::OnWritableState);
-  transport->SignalReadPacket.connect(this, &BaseChannel::OnPacketRead);
   transport->SignalDtlsState.connect(this, &BaseChannel::OnDtlsState);
   transport->SignalSentPacket.connect(this, &BaseChannel::SignalSentPacket_n);
   transport->ice_transport()->SignalSelectedCandidatePairChanged.connect(
@@ -411,7 +412,6 @@ void BaseChannel::DisconnectFromDtlsTransport(
                                  false);
 
   transport->SignalWritableState.disconnect(this);
-  transport->SignalReadPacket.disconnect(this);
   transport->SignalDtlsState.disconnect(this);
   transport->SignalSentPacket.disconnect(this);
   transport->ice_transport()->SignalSelectedCandidatePairChanged.disconnect(
@@ -422,7 +422,6 @@ void BaseChannel::ConnectToPacketTransport(
     rtc::PacketTransportInternal* transport) {
   RTC_DCHECK_RUN_ON(network_thread_);
   transport->SignalWritableState.connect(this, &BaseChannel::OnWritableState);
-  transport->SignalReadPacket.connect(this, &BaseChannel::OnPacketRead);
   transport->SignalSentPacket.connect(this, &BaseChannel::SignalSentPacket_n);
 }
 
@@ -430,7 +429,6 @@ void BaseChannel::DisconnectFromPacketTransport(
     rtc::PacketTransportInternal* transport) {
   RTC_DCHECK_RUN_ON(network_thread_);
   transport->SignalWritableState.disconnect(this);
-  transport->SignalReadPacket.disconnect(this);
   transport->SignalSentPacket.disconnect(this);
 }
 
@@ -576,22 +574,6 @@ void BaseChannel::OnWritableState(rtc::PacketTransportInternal* transport) {
   UpdateWritableState_n();
 }
 
-void BaseChannel::OnPacketRead(rtc::PacketTransportInternal* transport,
-                               const char* data,
-                               size_t len,
-                               const rtc::PacketTime& packet_time,
-                               int flags) {
-  TRACE_EVENT0("webrtc", "BaseChannel::OnPacketRead");
-  // OnPacketRead gets called from P2PSocket; now pass data to MediaEngine
-  RTC_DCHECK(network_thread_->IsCurrent());
-
-  // When using RTCP multiplexing we might get RTCP packets on the RTP
-  // transport. We feed RTP traffic into the demuxer to determine if it is RTCP.
-  bool rtcp = PacketIsRtcp(transport, data, len);
-  rtc::CopyOnWriteBuffer packet(data, len);
-  HandlePacket(rtcp, &packet, packet_time);
-}
-
 void BaseChannel::OnDtlsState(DtlsTransportInternal* transport,
                               DtlsTransportState state) {
   if (!ShouldSetupDtlsSrtp_n()) {
@@ -641,13 +623,6 @@ void BaseChannel::OnTransportReadyToSend(bool ready) {
       Bind(&MediaChannel::OnReadyToSend, media_channel_, ready));
 }
 
-bool BaseChannel::PacketIsRtcp(const rtc::PacketTransportInternal* transport,
-                               const char* data,
-                               size_t len) {
-  return (transport == rtp_transport_.rtcp_packet_transport() ||
-          rtcp_mux_filter_.DemuxRtcp(data, static_cast<int>(len)));
-}
-
 bool BaseChannel::SendPacket(bool rtcp,
                              rtc::CopyOnWriteBuffer* packet,
                              const rtc::PacketOptions& options) {
@@ -680,7 +655,7 @@ bool BaseChannel::SendPacket(bool rtcp,
   // Protect ourselves against crazy data.
   if (!ValidPacket(rtcp, packet)) {
     LOG(LS_ERROR) << "Dropping outgoing " << content_name_ << " "
-                  << PacketType(rtcp)
+                  << RtpRtcpStringLiteral(rtcp)
                   << " packet: wrong size=" << packet->size();
     return false;
   }
@@ -772,31 +747,13 @@ bool BaseChannel::SendPacket(bool rtcp,
   return rtp_transport_.SendPacket(rtcp, packet, updated_options, flags);
 }
 
-bool BaseChannel::WantsPacket(bool rtcp, const rtc::CopyOnWriteBuffer* packet) {
-  // Protect ourselves against crazy data.
-  if (!ValidPacket(rtcp, packet)) {
-    LOG(LS_ERROR) << "Dropping incoming " << content_name_ << " "
-                  << PacketType(rtcp)
-                  << " packet: wrong size=" << packet->size();
-    return false;
-  }
-  if (rtcp) {
-    // Permit all (seemingly valid) RTCP packets.
-    return true;
-  }
-  // Check whether we handle this payload.
-  return bundle_filter_.DemuxPacket(packet->data(), packet->size());
+bool BaseChannel::HandlesPayloadType(int packet_type) const {
+  return rtp_transport_.HandlesPayloadType(packet_type);
 }
 
-void BaseChannel::HandlePacket(bool rtcp, rtc::CopyOnWriteBuffer* packet,
-                               const rtc::PacketTime& packet_time) {
-  RTC_DCHECK(network_thread_->IsCurrent());
-  if (!WantsPacket(rtcp, packet)) {
-    return;
-  }
-
-  // We are only interested in the first rtp packet because that
-  // indicates the media has started flowing.
+void BaseChannel::OnPacketReceived(bool rtcp,
+                                   rtc::CopyOnWriteBuffer& packet,
+                                   const rtc::PacketTime& packet_time) {
   if (!has_received_packet_ && !rtcp) {
     has_received_packet_ = true;
     signaling_thread()->Post(RTC_FROM_HERE, this, MSG_FIRSTPACKETRECEIVED);
@@ -805,8 +762,8 @@ void BaseChannel::HandlePacket(bool rtcp, rtc::CopyOnWriteBuffer* packet,
   // Unprotect the packet, if needed.
   if (srtp_filter_.IsActive()) {
     TRACE_EVENT0("webrtc", "SRTP Decode");
-    char* data = packet->data<char>();
-    int len = static_cast<int>(packet->size());
+    char* data = packet.data<char>();
+    int len = static_cast<int>(packet.size());
     bool res;
     if (!rtcp) {
       res = srtp_filter_.UnprotectRtp(data, len, &len);
@@ -816,8 +773,8 @@ void BaseChannel::HandlePacket(bool rtcp, rtc::CopyOnWriteBuffer* packet,
         GetRtpSeqNum(data, len, &seq_num);
         GetRtpSsrc(data, len, &ssrc);
         LOG(LS_ERROR) << "Failed to unprotect " << content_name_
-                      << " RTP packet: size=" << len
-                      << ", seqnum=" << seq_num << ", SSRC=" << ssrc;
+                      << " RTP packet: size=" << len << ", seqnum=" << seq_num
+                      << ", SSRC=" << ssrc;
         return;
       }
     } else {
@@ -831,7 +788,7 @@ void BaseChannel::HandlePacket(bool rtcp, rtc::CopyOnWriteBuffer* packet,
       }
     }
 
-    packet->SetSize(len);
+    packet.SetSize(len);
   } else if (srtp_required_) {
     // Our session description indicates that SRTP is required, but we got a
     // packet before our SRTP filter is active. This means either that
@@ -844,20 +801,21 @@ void BaseChannel::HandlePacket(bool rtcp, rtc::CopyOnWriteBuffer* packet,
     //    before sending  media, to prevent weird failure modes, so it's fine
     //    for us to just eat packets here. This is all sidestepped if RTCP mux
     //    is used anyway.
-    LOG(LS_WARNING) << "Can't process incoming " << PacketType(rtcp)
+    LOG(LS_WARNING) << "Can't process incoming " << RtpRtcpStringLiteral(rtcp)
                     << " packet when SRTP is inactive and crypto is required";
     return;
   }
 
   invoker_.AsyncInvoke<void>(
       RTC_FROM_HERE, worker_thread_,
-      Bind(&BaseChannel::OnPacketReceived, this, rtcp, *packet, packet_time));
+      Bind(&BaseChannel::ProcessPacket, this, rtcp, packet, packet_time));
 }
 
-void BaseChannel::OnPacketReceived(bool rtcp,
-                                   const rtc::CopyOnWriteBuffer& packet,
-                                   const rtc::PacketTime& packet_time) {
+void BaseChannel::ProcessPacket(bool rtcp,
+                                const rtc::CopyOnWriteBuffer& packet,
+                                const rtc::PacketTime& packet_time) {
   RTC_DCHECK(worker_thread_->IsCurrent());
+
   // Need to copy variable because OnRtcpReceived/OnPacketReceived
   // requires non-const pointer to buffer. This doesn't memcpy the actual data.
   rtc::CopyOnWriteBuffer data(packet);
@@ -987,7 +945,7 @@ bool BaseChannel::SetupDtlsSrtp_n(bool rtcp) {
   }
 
   LOG(LS_INFO) << "Installing keys from DTLS-SRTP on " << content_name() << " "
-               << PacketType(rtcp);
+               << RtpRtcpStringLiteral(rtcp);
 
   int key_len;
   int salt_len;
@@ -1448,6 +1406,10 @@ void BaseChannel::OnMessage(rtc::Message *pmsg) {
   }
 }
 
+void BaseChannel::AddHandledPayloadType(int payload_type) {
+  rtp_transport_.AddHandledPayloadType(payload_type);
+}
+
 void BaseChannel::FlushRtcpMessages_n() {
   // Flush all remaining RTCP messages. This should only be called in
   // destructor.
@@ -1659,15 +1621,13 @@ void VoiceChannel::GetActiveStreams_w(AudioInfo::StreamList* actives) {
   media_channel()->GetActiveStreams(actives);
 }
 
-void VoiceChannel::OnPacketRead(rtc::PacketTransportInternal* transport,
-                                const char* data,
-                                size_t len,
-                                const rtc::PacketTime& packet_time,
-                                int flags) {
-  BaseChannel::OnPacketRead(transport, data, len, packet_time, flags);
+void VoiceChannel::OnPacketReceived(bool rtcp,
+                                    rtc::CopyOnWriteBuffer& packet,
+                                    const rtc::PacketTime& packet_time) {
+  BaseChannel::OnPacketReceived(rtcp, packet, packet_time);
   // Set a flag when we've received an RTP packet. If we're waiting for early
   // media, this will disable the timeout.
-  if (!received_media_ && !PacketIsRtcp(transport, data, len)) {
+  if (!received_media_ && !rtcp) {
     received_media_ = true;
   }
 }
@@ -1766,7 +1726,7 @@ bool VoiceChannel::SetLocalContent_w(const MediaContentDescription* content,
     return false;
   }
   for (const AudioCodec& codec : audio->codecs()) {
-    bundle_filter()->AddPayloadType(codec.id);
+    AddHandledPayloadType(codec.id);
   }
   last_recv_params_ = recv_params;
 
@@ -2039,7 +1999,7 @@ bool VideoChannel::SetLocalContent_w(const MediaContentDescription* content,
     return false;
   }
   for (const VideoCodec& codec : video->codecs()) {
-    bundle_filter()->AddPayloadType(codec.id);
+    AddHandledPayloadType(codec.id);
   }
   last_recv_params_ = recv_params;
 
@@ -2234,7 +2194,7 @@ bool RtpDataChannel::SetLocalContent_w(const MediaContentDescription* content,
     return false;
   }
   for (const DataCodec& codec : data->codecs()) {
-    bundle_filter()->AddPayloadType(codec.id);
+    AddHandledPayloadType(codec.id);
   }
   last_recv_params_ = recv_params;