Reset TURN port NONCE when a new socket is created.

webrtc/p2p/base/turnserver.h

Index: webrtc/p2p/base/turnserver.h
diff --git a/webrtc/p2p/base/turnserver.h b/webrtc/p2p/base/turnserver.h
index 113bd4c4623d06c118a1b05ede79bceee2d72ad6..df5b2ff2acfac92efbbd0130dc83b87a0f20a7ae 100644
--- a/webrtc/p2p/base/turnserver.h
+++ b/webrtc/p2p/base/turnserver.h
@@ -199,6 +199,12 @@ class TurnServer : public sigslot::has_slots<> {
   // Specifies the factory to use for creating external sockets.
   void SetExternalSocketFactory(rtc::PacketSocketFactory* factory,
                                 const rtc::SocketAddress& address);
+  // Visible for testing.
+  std::string GenerateNonce(uint32_t now) const;
+  // For testing only.
+  void SetTimestampForNextNonce(uint32_t timestamp) {
+    ts_for_next_nonce_ = timestamp;
+  }

[Taylor Brandstetter, 2016/01/26 02:02:06]

Instead of this, would it be reasonable to add a
"mismatch_error_on_duplicate_nonce_" mode to the TurnServer, to simulate the
google3 TURN server? If the flag is set, you could enumerate the current
allocations, looking for one where "last_nonce" matches.

This would possibly be valuable for other tests in the future, at it matches
what we've done for other things like "enable_otu_nonce_" and
"reject_private_addresses_".

[honghaiz3, 2016/01/27 01:45:23]

Looking through all allocations to find the duplicate nonce could be quite
expensive. Another way would be to remember the allocate when the first request
with empty nonce comes in, but that will change the behavior of turnserver
substantially. Will keep this as we discussed.  

[Taylor Brandstetter, 2016/01/27 02:02:42]

Now that we discussed this and I understand the problem better, I agree it would
require a major redesign of the TurnServer class. So what you have here is good.

 
  private:
   void OnInternalPacket(rtc::AsyncPacketSocket* socket, const char* data,
@@ -221,7 +227,6 @@ class TurnServer : public sigslot::has_slots<> {
   bool CheckAuthorization(TurnServerConnection* conn, const StunMessage* msg,
                           const char* data, size_t size,
                           const std::string& key);
-  std::string GenerateNonce() const;
   bool ValidateNonce(const std::string& nonce) const;
 
   TurnServerAllocation* FindAllocation(TurnServerConnection* conn);
@@ -270,6 +275,10 @@ class TurnServer : public sigslot::has_slots<> {
 
   AllocationMap allocations_;
 
+  // For testing only. If this is non-zero, the next NONCE will be generated
+  // from this value, and it will be reset to 0 after generating the NONCE.
+  uint32_t ts_for_next_nonce_ = 0;
+
   friend class TurnServerAllocation;
 };