Implement the "sanity checks" described in b/9509040: Incoming packets

net/quic/quic_dispatcher.h

 // Copyright 2014 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_QUIC_QUIC_DISPATCHER_H_
 #define NET_QUIC_QUIC_DISPATCHER_H_
 
@@ skipping 115 matching lines @@
 
  protected:
   virtual QuicSession* CreateQuicSession(QuicConnectionId connection_id,
                                          const IPEndPoint& server_address,
                                          const IPEndPoint& client_address);
 
   // Called by |framer_visitor_| when the public header has been parsed.
   virtual bool OnUnauthenticatedPublicHeader(
       const QuicPacketPublicHeader& header);
 
+  // Called by OnUnauthenticatedPublicHeader when the packet is not for a
+  // connection that the dispatcher has a record of, but is not handled by
+  // certain simple processing rules.  This method may apply validity checks to
+  // reject stray packets.  If the packet appears to be valid, it calls
+  // CreateQuicSession to create a new session for the packet.  Returns the
+  // QuicSession that was created, or nullptr if the packet failed the validity
+  // checks.
+  virtual QuicSession* AdditionalValidityChecksThenCreateSession(
+      const QuicPacketPublicHeader& header,
+      QuicConnectionId connection_id);
+
   // Create and return the time wait list manager for this dispatcher, which
   // will be owned by the dispatcher as time_wait_list_manager_
   virtual QuicTimeWaitListManager* CreateQuicTimeWaitListManager();
 
   QuicTimeWaitListManager* time_wait_list_manager() {
     return time_wait_list_manager_.get();
   }
 
   const QuicVersionVector& supported_versions() const {
     return supported_versions_;
@@ skipping 95 matching lines @@
 
   QuicFramer framer_;
   scoped_ptr<QuicFramerVisitor> framer_visitor_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicDispatcher);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_DISPATCHER_H_