Fix active tcp port to 9

webrtc/p2p/base/tcpport.cc

 /*
  *  Copyright 2004 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 166 matching lines @@
                     << socket_->GetState();
     if (socket_->GetState() == rtc::AsyncPacketSocket::STATE_BOUND ||
         socket_->GetState() == rtc::AsyncPacketSocket::STATE_CLOSED)
       AddAddress(socket_->GetLocalAddress(), socket_->GetLocalAddress(),
                  rtc::SocketAddress(), TCP_PROTOCOL_NAME, "",
                  TCPTYPE_PASSIVE_STR, LOCAL_PORT_TYPE,
                  ICE_TYPE_PREFERENCE_HOST_TCP, 0, true);
   } else {
     LOG_J(LS_INFO, this) << "Not listening due to firewall restrictions.";
     // Note: We still add the address, since otherwise the remote side won't
-    // recognize our incoming TCP connections.
-    AddAddress(rtc::SocketAddress(ip(), 0), rtc::SocketAddress(ip(), 0),
-               rtc::SocketAddress(), TCP_PROTOCOL_NAME, "", TCPTYPE_ACTIVE_STR,
-               LOCAL_PORT_TYPE, ICE_TYPE_PREFERENCE_HOST_TCP, 0, true);
+    // recognize our incoming TCP connections. According to
+    // https://tools.ietf.org/html/rfc6544#section-4.5, for active candidate,
+    // the port must be set to the discard port, i.e. 9.
+    AddAddress(rtc::SocketAddress(ip(), DISCARD_PORT),
+               rtc::SocketAddress(ip(), 0), rtc::SocketAddress(),
+               TCP_PROTOCOL_NAME, "", TCPTYPE_ACTIVE_STR, LOCAL_PORT_TYPE,
+               ICE_TYPE_PREFERENCE_HOST_TCP, 0, true);
   }
 }
 
 int TCPPort::SendTo(const void* data, size_t size,
                     const rtc::SocketAddress& addr,
                     const rtc::PacketOptions& options,
                     bool payload) {
   rtc::AsyncPacketSocket * socket = NULL;
   TCPConnection* conn = static_cast<TCPConnection*>(GetConnection(addr));
 
@@ skipping 297 matching lines @@
 void TCPConnection::ConnectSocketSignals(rtc::AsyncPacketSocket* socket) {
   if (outgoing_) {
     socket->SignalConnect.connect(this, &TCPConnection::OnConnect);
   }
   socket->SignalReadPacket.connect(this, &TCPConnection::OnReadPacket);
   socket->SignalReadyToSend.connect(this, &TCPConnection::OnReadyToSend);
   socket->SignalClose.connect(this, &TCPConnection::OnClose);
 }
 
 }  // namespace cricket