Reset TURN port NONCE when a new socket is created.

webrtc/p2p/base/turnport.cc

Index: webrtc/p2p/base/turnport.cc
diff --git a/webrtc/p2p/base/turnport.cc b/webrtc/p2p/base/turnport.cc
index 5ed93dd1d84a05b445aeaeeeed47b3ab26172c3d..1643aff186a0ba4068dbf933befd2c43a4aa3894 100644
--- a/webrtc/p2p/base/turnport.cc
+++ b/webrtc/p2p/base/turnport.cc
@@ -433,6 +433,7 @@ void TurnPort::OnAllocateMismatch() {
   }
   socket_ = NULL;
 
+  ResetNonce();
   PrepareAddress();
   ++allocate_mismatch_retries_;
 }
@@ -764,6 +765,7 @@ void TurnPort::OnMessage(rtc::Message* message) {
         ASSERT(!SharedSocket());
         delete socket_;
         socket_ = NULL;
+        ResetNonce();

[pthatcher1, 2016/01/19 01:48:38]

It looks like we don't have a unit test for this.  Should we?

[honghaiz3, 2016/01/20 00:54:38]

I removed this change because
The alternate server response is the first-step processing a turnserver will do
when handling a stun request. So it should be always empty, unless the server
has included a NONCE in the response. In that case, it is not clear whether it
is the best practice to reset the NONCE (because no server is doing that now). 

Allocate-mismatch is different. A server first checks whether the nonce is set.
If not, it returns an error response with NONCE. When the client sends a request
with the NONCE, the server will check for allocate-mismatch. 

         PrepareAddress();
       }
       break;
@@ -927,6 +929,12 @@ bool TurnPort::UpdateNonce(StunMessage* response) {
   return true;
 }
 
+void TurnPort::ResetNonce() {
+  hash_.clear();
+  nonce_.clear();
+  realm_.clear();
+}
+
 static bool MatchesIP(TurnEntry* e, rtc::IPAddress ipaddr) {
   return e->address().ipaddr() == ipaddr;
 }