Reset TURN port NONCE when a new socket is created.

webrtc/p2p/base/turnport_unittest.cc

Index: webrtc/p2p/base/turnport_unittest.cc
diff --git a/webrtc/p2p/base/turnport_unittest.cc b/webrtc/p2p/base/turnport_unittest.cc
index 916162575fee803093aff79ea89afde02cae5902..dd73ff7be3466c2d58b408e873694570eeebe4eb 100644
--- a/webrtc/p2p/base/turnport_unittest.cc
+++ b/webrtc/p2p/base/turnport_unittest.cc
@@ -605,6 +605,39 @@ TEST_F(TurnPortTest, TestTurnAllocateBadPassword) {
   ASSERT_EQ(0U, turn_port_->Candidates().size());
 }
 
+// Tests that TURN port NONCE will be reset when receiving an ALLOCATE MISMATCH

[pthatcher1, 2016/01/29 17:37:46]

NONCE => nonce, here and below

[honghaiz3, 2016/01/29 18:46:36]

Done.

+// error.
+TEST_F(TurnPortTest, TestTurnAllocateNonceResetAfterAllocateMismatch) {
+  // Do a normal allocation first.
+  CreateTurnPort(kTurnUsername, kTurnPassword, kTurnUdpProtoAddr);
+  turn_port_->PrepareAddress();
+  EXPECT_TRUE_WAIT(turn_ready_, kTimeout);
+  rtc::SocketAddress first_addr(turn_port_->socket()->GetLocalAddress());
+  // Destroy the turnport while keeping the drop probability to 1 to
+  // suppress the release of the allocation at the server.
+  ss_->set_drop_probability(1.0);
+  turn_port_.reset();
+  rtc::Thread::Current()->ProcessMessages(0);
+  ss_->set_drop_probability(0.0);

[pthatcher1, 2016/01/29 17:37:46]

What's the point of doing a normal allocation first if we just destroy the
turn_port_ anyway?  Wouldn't it be enough to just do one round of allocation,
but with the turn_server_.server()->SetTimestampForNextNonce(now); trick from
below?

[honghaiz3, 2016/01/29 18:46:36]

The first allocation is needed to generate the mismatch error.
The first one get an allocation.
When the second allocation is made, it gets the nonce error. 
When the third allocation is made, it gets a mismatch error.
The fourth allocation will be on a different port, but gets a nonce error. 
The fifth finally gets the allocation.   

+
+  // Force the socket server to assign the same port.
+  ss_->SetNextPortForTesting(first_addr.port());
+  turn_ready_ = false;
+  CreateTurnPort(kTurnUsername, kTurnPassword, kTurnUdpProtoAddr);
+
+  // It is expected that the turn port will first get a NONCE from the server
+  // using timestamp |now| but then get an allocate mismatch error and receive
+  // an even newer NONCE based on the system clock. |now| is chosen so that
+  // the two NONCEs generated by the server will be different.
+  uint32_t now = rtc::Time() - 1;

[pthatcher1, 2016/01/29 17:37:46]

Well it's not really "now", is it?  Isn't it "before"?

[honghaiz3, 2016/01/29 18:46:36]

Done.

+  turn_server_.server()->SetTimestampForNextNonce(now);
+  std::string next_nonce = turn_server_.server()->GenerateNonce(now);

[pthatcher1, 2016/01/29 17:37:46]

Wouldn't a better name be first_nonce?

[honghaiz3, 2016/01/29 18:46:36]

Done.

+  turn_port_->PrepareAddress();
+
+  EXPECT_TRUE_WAIT(turn_ready_, kTimeout);
+  EXPECT_NE(next_nonce, turn_port_->nonce());
+}
+
 // Tests that a new local address is created after
 // STUN_ERROR_ALLOCATION_MISMATCH.
 TEST_F(TurnPortTest, TestTurnAllocateMismatch) {