Reset TURN port NONCE when a new socket is created.

webrtc/p2p/base/turnport_unittest.cc

 /*
  *  Copyright 2012 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.
  */
 #if defined(WEBRTC_POSIX)
@@ skipping 587 matching lines @@
 }
 
 // Try to do a TURN allocation with an invalid password.
 TEST_F(TurnPortTest, TestTurnAllocateBadPassword) {
   CreateTurnPort(kTurnUsername, "bad", kTurnUdpProtoAddr);
   turn_port_->PrepareAddress();
   EXPECT_TRUE_WAIT(turn_error_, kTimeout);
   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) {
   // 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());
 
   // Clear connected_ flag on turnport to suppress the release of
@@ skipping 373 matching lines @@
   turn_port_->PrepareAddress();
   ASSERT_TRUE_WAIT(turn_error_, kResolverTimeout);
   EXPECT_TRUE(turn_port_->Candidates().empty());
   turn_port_.reset();
   rtc::Thread::Current()->Post(this, MSG_TESTFINISH);
   // Waiting for above message to be processed.
   ASSERT_TRUE_WAIT(test_finish_, kTimeout);
   EXPECT_EQ(last_fd_count, GetFDCount());
 }
 #endif