Make QUIC version negotiation stateless. The QUIC dispatcher now detects version mismatch before cr…

net/tools/quic/quic_dispatcher.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // A server side dispatcher which dispatches a given client's data to their
 // stream.
 
 #ifndef NET_TOOLS_QUIC_QUIC_DISPATCHER_H_
 #define NET_TOOLS_QUIC_QUIC_DISPATCHER_H_
 
@@ skipping 185 matching lines @@
 
   QuicPacketWriter* writer() { return writer_.get(); }
 
   // Creates per-connection packet writers out of the QuicDispatcher's shared
   // QuicPacketWriter. The per-connection writers' IsWriteBlocked() state must
   // always be the same as the shared writer's IsWriteBlocked(), or else the
   // QuicDispatcher::OnCanWrite logic will not work. (This will hopefully be
   // cleaned up for bug 16950226.)
   virtual QuicPacketWriter* CreatePerConnectionWriter();
 
+  // Returns true if a session should be created for a connection with an
+  // unknown version identified by |version_tag|.
+  virtual bool ShouldCreateSessionForUnknownVersion(QuicTag version_tag);
+
   void SetLastError(QuicErrorCode error);
 
  private:
   friend class net::test::QuicDispatcherPeer;
 
   // Removes the session from the session map and write blocked list, and adds
   // the ConnectionId to the time-wait list.  If |session_closed_statelessly| is
   // true, any future packets for the ConnectionId will be black-holed.
   void CleanUpSession(SessionMap::iterator it, bool session_closed_statelessly);
 
@@ skipping 26 matching lines @@
   // This vector contains QUIC versions which we currently support.
   // This should be ordered such that the highest supported version is the first
   // element, with subsequent elements in descending order (versions can be
   // skipped as necessary).
   const QuicVersionVector supported_versions_;
 
   // Information about the packet currently being handled.
   IPEndPoint current_client_address_;
   IPEndPoint current_server_address_;
   const QuicEncryptedPacket* current_packet_;
+  QuicConnectionId current_connection_id_;
 
   QuicFramer framer_;
 
   // The last error set by SetLastError(), which is called by
   // framer_visitor_->OnError().
   QuicErrorCode last_error_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicDispatcher);
 };
 
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_QUIC_DISPATCHER_H_