Add flakiness check if there is no received packets in a certain period.

webrtc/p2p/base/p2ptransportchannel.cc

Index: webrtc/p2p/base/p2ptransportchannel.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel.cc b/webrtc/p2p/base/p2ptransportchannel.cc
index 83bcf840ee4350e39ad550738e676d1641f5dabd..0f6ea05bc6b42ffa4dd6e53b2d1ae2d0ae400057 100644
--- a/webrtc/p2p/base/p2ptransportchannel.cc
+++ b/webrtc/p2p/base/p2ptransportchannel.cc
@@ -25,6 +25,7 @@ namespace {
 enum {
   MSG_SORT = 1,
   MSG_PING,
+  MSG_CHECK_RECEIVING
 };
 
 // When the socket is unwritable, we will use 10 Kbps (ignoring IP+UDP headers)
@@ -40,6 +41,8 @@ static const uint32 UNWRITABLE_DELAY = 1000 * PING_PACKET_SIZE / 10000;  // 50ms
 // make sure it is pinged at this rate.
 static const uint32 MAX_CURRENT_WRITABLE_DELAY = 900;  // 2*WRITABLE_DELAY - bit
 
+static const uint32 MIN_CHECK_RECEIVING_DELAY = 50;  // ms
+
 // The minimum improvement in RTT that justifies a switch.
 static const double kMinImprovement = 10;
 
@@ -193,7 +196,9 @@ P2PTransportChannel::P2PTransportChannel(const std::string& content_name,
     remote_ice_mode_(ICEMODE_FULL),
     ice_role_(ICEROLE_UNKNOWN),
     tiebreaker_(0),
-    remote_candidate_generation_(0) {
+    remote_candidate_generation_(0),
+    check_receiving_delay_(MIN_CHECK_RECEIVING_DELAY * 5),
+    receiving_timeout_(MIN_CHECK_RECEIVING_DELAY * 50) {

[pthatcher1, 2015/07/06 22:04:47]

It seems like we should add a set_receiving_timeout method to allow apps to
change the timeout.  Perhaps you were planning on adding that in a future CL?  I
think it would make sense in this CL.

[honghaiz3, 2015/08/05 23:56:57]

Done. Yes. This is needed for the tests. 

 }
 
 P2PTransportChannel::~P2PTransportChannel() {
@@ -369,6 +374,9 @@ void P2PTransportChannel::Connect() {
 
   // Start pinging as the ports come in.
   thread()->Post(this, MSG_PING);
+
+  thread()->PostDelayed(
+      check_receiving_delay_, this, MSG_CHECK_RECEIVING);
 }
 
 // A new port is available, attempt to make connections for it
@@ -1067,6 +1075,8 @@ void P2PTransportChannel::SwitchBestConnectionTo(Connection* conn) {
     LOG_J(LS_INFO, this) << "New best connection: "
                          << best_connection_->ToString();
     SignalRouteChange(this, best_connection_->remote_candidate());
+    // When it just switched to a best connection, set receiving to true.
+    set_receiving(true);
   } else {
     LOG_J(LS_INFO, this) << "No best connection";
   }
@@ -1148,6 +1158,9 @@ void P2PTransportChannel::OnMessage(rtc::Message *pmsg) {
     case MSG_PING:
       OnPing();
       break;
+    case MSG_CHECK_RECEIVING:
+      OnCheckReceiving();
+      break;
     default:
       ASSERT(false);
       break;
@@ -1176,6 +1189,19 @@ void P2PTransportChannel::OnPing() {
   thread()->PostDelayed(delay, this, MSG_PING);
 }
 
+void P2PTransportChannel::OnCheckReceiving() {
+  // Check receiving only if the best connection has received data packets
+  // because we want to detect not receiving any packets only after the media
+  // have started flowing.
+  if (best_connection_ && best_connection_->recv_total_bytes() > 0) {
+    bool receiving = rtc::Time() <=
+        best_connection_->last_received() + receiving_timeout_;
+    set_receiving(receiving);
+  }
+
+  thread()->PostDelayed(check_receiving_delay_, this, MSG_CHECK_RECEIVING);
+}
+
 // Is the connection in a state for us to even consider pinging the other side?
 // We consider a connection pingable even if it's not connected because that's
 // how a TCP connection is kicked into reconnecting on the active side.