Dampening connection switch.

webrtc/p2p/base/p2ptransportchannel_unittest.cc

Index: webrtc/p2p/base/p2ptransportchannel_unittest.cc
diff --git a/webrtc/p2p/base/p2ptransportchannel_unittest.cc b/webrtc/p2p/base/p2ptransportchannel_unittest.cc
index cf54fc4a27fdcf6dbc4c615ae6216097b0f2dd01..dab8d580196595c91952a80ea0b2d7c17712262f 100644
--- a/webrtc/p2p/base/p2ptransportchannel_unittest.cc
+++ b/webrtc/p2p/base/p2ptransportchannel_unittest.cc
@@ -350,6 +350,8 @@ class P2PTransportChannelTestBase : public testing::Test,
         this, &P2PTransportChannelTestBase::OnReadPacket);
     channel->SignalRoleConflict.connect(
         this, &P2PTransportChannelTestBase::OnRoleConflict);
+    channel->SignalSelectedCandidatePairChanged.connect(
+        this, &P2PTransportChannelTestBase::OnSelectedCandidatePairChanged);
     channel->SetIceCredentials(local_ice_ufrag, local_ice_pwd);
     if (remote_ice_credential_source_ == FROM_SETICECREDENTIALS) {
       channel->SetRemoteIceCredentials(remote_ice_ufrag, remote_ice_pwd);
@@ -688,6 +690,19 @@ class P2PTransportChannelTestBase : public testing::Test,
                   new CandidatesData(ch, c));
     }
   }
+  void OnSelectedCandidatePairChanged(
+      TransportChannel* transport_channel,
+      CandidatePairInterface* selected_candidate_pair,
+      int last_sent_packet_id,
+      bool ready_to_send) {
+    ++selected_candidate_pair_switches_;
+  }
+
+  int get_and_reset_selected_candidate_pair_switches() {
+    int switches = selected_candidate_pair_switches_;
+    selected_candidate_pair_switches_ = 0;
+    return switches;
+  }
 
   void PauseCandidates(int endpoint) {
     GetEndpoint(endpoint)->save_candidates_ = true;
@@ -850,6 +865,7 @@ class P2PTransportChannelTestBase : public testing::Test,
   Endpoint ep2_;
   RemoteIceCredentialSource remote_ice_credential_source_ = FROM_CANDIDATE;
   bool force_relay_;
+  int selected_candidate_pair_switches_ = 0;
 };
 
 // The tests have only a few outcomes, which we predefine.
@@ -1867,6 +1883,7 @@ TEST_F(P2PTransportChannelMultihomedTest, DISABLED_TestBasic) {
 // Test that we can quickly switch links if an interface goes down.
 // The controlled side has two interfaces and one will die.
 TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControlledSide) {
+  rtc::ScopedFakeClock clock;
   AddAddress(0, kPublicAddrs[0]);
   // Adding alternate address will make sure |kPublicAddrs| has the higher
   // priority than others. This is due to FakeNetwork::AddInterface method.
@@ -1880,9 +1897,10 @@ TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControlledSide) {
   // Create channels and let them go writable, as usual.
   CreateChannels(1);
 
-  EXPECT_TRUE_WAIT_MARGIN(ep1_ch1()->receiving() && ep1_ch1()->writable() &&
-                              ep2_ch1()->receiving() && ep2_ch1()->writable(),
-                          1000, 1000);
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->receiving() && ep1_ch1()->writable() &&
+                                 ep2_ch1()->receiving() &&
+                                 ep2_ch1()->writable(),
+                             3000, clock);
   EXPECT_TRUE(ep1_ch1()->selected_connection() &&
               ep2_ch1()->selected_connection() &&
               LocalCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[0]) &&
@@ -1896,19 +1914,19 @@ TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControlledSide) {
   // Blackhole any traffic to or from the public addrs.
   LOG(LS_INFO) << "Failing over...";
   fw()->AddRule(false, rtc::FP_ANY, rtc::FD_ANY, kPublicAddrs[1]);
-  // The selected connections will switch, so keep references to them.
+  // The selected connections may switch, so keep references to them.
   const Connection* selected_connection1 = ep1_ch1()->selected_connection();
   const Connection* selected_connection2 = ep2_ch1()->selected_connection();
   // We should detect loss of receiving within 1 second or so.
-  EXPECT_TRUE_WAIT(
+  EXPECT_TRUE_SIMULATED_WAIT(
       !selected_connection1->receiving() && !selected_connection2->receiving(),
-      3000);
+      3000, clock);
 
   // We should switch over to use the alternate addr immediately on both sides
   // when we are not receiving.
-  EXPECT_TRUE_WAIT(ep1_ch1()->selected_connection()->receiving() &&
-                       ep2_ch1()->selected_connection()->receiving(),
-                   1000);
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->selected_connection()->receiving() &&
+                                 ep2_ch1()->selected_connection()->receiving(),
+                             3000, clock);
   EXPECT_TRUE(LocalCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[0]));
   EXPECT_TRUE(
       RemoteCandidate(ep1_ch1())->address().EqualIPs(kAlternateAddrs[1]));
@@ -1921,6 +1939,7 @@ TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControlledSide) {
 // Test that we can quickly switch links if an interface goes down.
 // The controlling side has two interfaces and one will die.
 TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControllingSide) {
+  rtc::ScopedFakeClock clock;
   // Adding alternate address will make sure |kPublicAddrs| has the higher
   // priority than others. This is due to FakeNetwork::AddInterface method.
   AddAddress(0, kAlternateAddrs[0]);
@@ -1933,9 +1952,10 @@ TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControllingSide) {
 
   // Create channels and let them go writable, as usual.
   CreateChannels(1);
-  EXPECT_TRUE_WAIT_MARGIN(ep1_ch1()->receiving() && ep1_ch1()->writable() &&
-                              ep2_ch1()->receiving() && ep2_ch1()->writable(),
-                          1000, 1000);
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->receiving() && ep1_ch1()->writable() &&
+                                 ep2_ch1()->receiving() &&
+                                 ep2_ch1()->writable(),
+                             3000, clock);
   EXPECT_TRUE(ep1_ch1()->selected_connection() &&
               ep2_ch1()->selected_connection() &&
               LocalCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[0]) &&
@@ -1953,15 +1973,15 @@ TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControllingSide) {
   const Connection* selected_connection1 = ep1_ch1()->selected_connection();
   const Connection* selected_connection2 = ep2_ch1()->selected_connection();
   // We should detect loss of receiving within 1 second or so.
-  EXPECT_TRUE_WAIT(
+  EXPECT_TRUE_SIMULATED_WAIT(
       !selected_connection1->receiving() && !selected_connection2->receiving(),
-      3000);
+      3000, clock);
 
-  // We should switch over to use the alternate addr immediately on both sides
+  // We should switch over to use the alternate addr on both sides
   // when we are not receiving.
-  EXPECT_TRUE_WAIT(ep1_ch1()->selected_connection()->receiving() &&
-                       ep2_ch1()->selected_connection()->receiving(),
-                   1000);
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->selected_connection()->receiving() &&
+                                 ep2_ch1()->selected_connection()->receiving(),
+                             3000, clock);
   EXPECT_TRUE(
     LocalCandidate(ep1_ch1())->address().EqualIPs(kAlternateAddrs[0]));
   EXPECT_TRUE(RemoteCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[1]));
@@ -1971,6 +1991,123 @@ TEST_F(P2PTransportChannelMultihomedTest, TestFailoverControllingSide) {
   DestroyChannels();
 }
 
+// Test that if an interface fails temporarily and then recovers quickly,
+// the selected connection will not switch.
+TEST_F(P2PTransportChannelMultihomedTest,
+       TestConnectionSwitchDampeningControlledSide) {
+  rtc::ScopedFakeClock clock;
+  AddAddress(0, kPublicAddrs[0]);
+  // Adding alternate address will make sure |kPublicAddrs| has the higher
+  // priority than others. This is due to FakeNetwork::AddInterface method.
+  AddAddress(1, kAlternateAddrs[1]);
+  AddAddress(1, kPublicAddrs[1]);
+
+  // Use only local ports for simplicity.
+  SetAllocatorFlags(0, kOnlyLocalPorts);
+  SetAllocatorFlags(1, kOnlyLocalPorts);
+
+  // Create channels and let them go writable, as usual.
+  CreateChannels(1);
+
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->receiving() && ep1_ch1()->writable() &&
+                                 ep2_ch1()->receiving() &&
+                                 ep2_ch1()->writable(),
+                             3000, clock);
+  EXPECT_TRUE(ep1_ch1()->selected_connection() &&
+              ep2_ch1()->selected_connection() &&
+              LocalCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[0]) &&
+              RemoteCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[1]));
+
+  // Make the receiving timeout shorter for testing.
+  IceConfig config = CreateIceConfig(1000, GATHER_ONCE);
+  ep1_ch1()->SetIceConfig(config);
+  ep2_ch1()->SetIceConfig(config);
+  get_and_reset_selected_candidate_pair_switches();
+
+  // Blackhole any traffic to or from the public addrs.
+  LOG(LS_INFO) << "Failing over...";
+  fw()->AddRule(false, rtc::FP_ANY, rtc::FD_ANY, kPublicAddrs[1]);
+
+  // The selected connections may switch, so keep references to them.
+  const Connection* selected_connection1 = ep1_ch1()->selected_connection();
+  const Connection* selected_connection2 = ep2_ch1()->selected_connection();
+  // We should detect loss of receiving within 1 second or so.
+  EXPECT_TRUE_SIMULATED_WAIT(
+      !selected_connection1->receiving() && !selected_connection2->receiving(),
+      3000, clock);
+  // After a short while, the link recovers itself.
+  SIMULATED_WAIT(false, 10, clock);
+  fw()->ClearRules();
+
+  // We should remain on the public address on both sides and no connection
+  // switches should have happened.
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->selected_connection()->receiving() &&
+                                 ep2_ch1()->selected_connection()->receiving(),
+                             3000, clock);
+  EXPECT_TRUE(RemoteCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[1]));
+  EXPECT_TRUE(LocalCandidate(ep2_ch1())->address().EqualIPs(kPublicAddrs[1]));
+  EXPECT_EQ(0, get_and_reset_selected_candidate_pair_switches());
+
+  DestroyChannels();
+}
+
+// Test that if an interface fails temporarily and then recovers quickly,
+// the selected connection will not switch.
+TEST_F(P2PTransportChannelMultihomedTest,
+       TestConnectionSwitchDampeningControllingSide) {
+  rtc::ScopedFakeClock clock;
+  // Adding alternate address will make sure |kPublicAddrs| has the higher
+  // priority than others. This is due to FakeNetwork::AddInterface method.
+  AddAddress(0, kAlternateAddrs[0]);
+  AddAddress(0, kPublicAddrs[0]);
+  AddAddress(1, kPublicAddrs[1]);
+
+  // Use only local ports for simplicity.
+  SetAllocatorFlags(0, kOnlyLocalPorts);
+  SetAllocatorFlags(1, kOnlyLocalPorts);
+
+  // Create channels and let them go writable, as usual.
+  CreateChannels(1);
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->receiving() && ep1_ch1()->writable() &&
+                                 ep2_ch1()->receiving() &&
+                                 ep2_ch1()->writable(),
+                             3000, clock);
+  EXPECT_TRUE(ep1_ch1()->selected_connection() &&
+              ep2_ch1()->selected_connection() &&
+              LocalCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[0]) &&
+              RemoteCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[1]));
+
+  // Make the receiving timeout shorter for testing.
+  IceConfig config = CreateIceConfig(1000, GATHER_ONCE);
+  ep1_ch1()->SetIceConfig(config);
+  ep2_ch1()->SetIceConfig(config);
+  get_and_reset_selected_candidate_pair_switches();
+
+  // Blackhole any traffic to or from the public addrs.
+  LOG(LS_INFO) << "Failing over...";
+  fw()->AddRule(false, rtc::FP_ANY, rtc::FD_ANY, kPublicAddrs[0]);
+  // The selected connections may switch, so keep references to them.
+  const Connection* selected_connection1 = ep1_ch1()->selected_connection();
+  const Connection* selected_connection2 = ep2_ch1()->selected_connection();
+  // We should detect loss of receiving within 1 second or so.
+  EXPECT_TRUE_SIMULATED_WAIT(
+      !selected_connection1->receiving() && !selected_connection2->receiving(),
+      3000, clock);
+  // The link recovers after a short while.
+  SIMULATED_WAIT(false, 10, clock);
+  fw()->ClearRules();
+
+  // We should not switch to the alternate addr on both sides because of the
+  // dampening.
+  EXPECT_TRUE_SIMULATED_WAIT(ep1_ch1()->selected_connection()->receiving() &&
+                                 ep2_ch1()->selected_connection()->receiving(),
+                             3000, clock);
+  EXPECT_TRUE(LocalCandidate(ep1_ch1())->address().EqualIPs(kPublicAddrs[0]));
+  EXPECT_TRUE(RemoteCandidate(ep2_ch1())->address().EqualIPs(kPublicAddrs[0]));
+  EXPECT_EQ(0, get_and_reset_selected_candidate_pair_switches());
+  DestroyChannels();
+}
+
 // Tests that a Wifi-Wifi connection has the highest precedence.
 TEST_F(P2PTransportChannelMultihomedTest, TestPreferWifiToWifiConnection) {
   // The interface names are chosen so that |cellular| would have higher