net/tools/quic/quic_time_wait_list_manager.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 //
   5 // Handles packets for guids in time wait state by discarding the packet and
   6 // sending the clients a public reset packet with exponential backoff.
   7
   8 #ifndef NET_TOOLS_QUIC_QUIC_TIME_WAIT_LIST_MANAGER_H_
   9 #define NET_TOOLS_QUIC_QUIC_TIME_WAIT_LIST_MANAGER_H_
  10
  11 #include <deque>
  12
  13 #include "base/containers/hash_tables.h"
  14 #include "base/strings/string_piece.h"
  15 #include "net/quic/quic_blocked_writer_interface.h"
  16 #include "net/quic/quic_framer.h"
  17 #include "net/quic/quic_protocol.h"
  18 #include "net/tools/flip_server/epoll_server.h"
  19 #include "net/tools/quic/quic_epoll_clock.h"
  20 #include "net/tools/quic/quic_packet_writer.h"
  21
  22 namespace net {
  23 namespace tools {
  24
  25 class GuidCleanUpAlarm;
  26
  27 // Maintains a list of all guids that have been recently closed. A guid lives in
  28 // this state for kTimeWaitPeriod. All packets received for guids in this state
  29 // are handed over to the QuicTimeWaitListManager by the QuicDispatcher. It also
  30 // decides whether we should send a public reset packet to the client which sent
  31 // a packet with the guid in time wait state and sends it when appropriate.
  32 // After the guid expires its time wait period, a new connection/session will be
  33 // created if a packet is received for this guid.
  34 class QuicTimeWaitListManager : public QuicBlockedWriterInterface,
  35                                 public QuicFramerVisitorInterface {
  36  public:
  37   // writer - the entity that writes to the socket. (Owned by the dispatcher)
  38   // epoll_server - used to run clean up alarms. (Owned by the dispatcher)
  39   QuicTimeWaitListManager(QuicPacketWriter* writer,
  40                           EpollServer* epoll_server);
  41   virtual ~QuicTimeWaitListManager();
  42
  43   // Adds the given guid to time wait state for kTimeWaitPeriod. Henceforth,
  44   // any packet bearing this guid should not be processed while the guid remains
  45   // in this list. Public reset packets are sent to the clients by the time wait
  46   // list manager that send packets to guids in this state. DCHECKs that guid is
  47   // not already on the list. Pass in the version as well so that if a public
  48   // reset packet needs to be sent the framer version can be set first.
  49   void AddGuidToTimeWait(QuicGuid guid, QuicVersion version);
  50
  51   // Returns true if the guid is in time wait state, false otherwise. Packets
  52   // received for this guid should not lead to creation of new QuicSessions.
  53   bool IsGuidInTimeWait(QuicGuid guid) const;
  54
  55   // Called when a packet is received for a guid that is in time wait state.
  56   // Sends a public reset packet to the client which sent this guid. Sending
  57   // of the public reset packet is throttled by using exponential back off.
  58   // DCHECKs for the guid to be in time wait state.
  59   // virtual to override in tests.
  60   virtual void ProcessPacket(const IPEndPoint& server_address,
  61                              const IPEndPoint& client_address,
  62                              QuicGuid guid,
  63                              const QuicEncryptedPacket& packet);
  64
  65   // Called by the dispatcher when the underlying socket becomes writable again,
  66   // since we might need to send pending public reset packets which we didn't
  67   // send because the underlying socket was write blocked.
  68   virtual bool OnCanWrite() OVERRIDE;
  69
  70   // Used to delete guid entries that have outlived their time wait period.
  71   void CleanUpOldGuids();
  72
  73   // FramerVisitorInterface
  74   virtual void OnError(QuicFramer* framer) OVERRIDE;
  75   virtual bool OnProtocolVersionMismatch(QuicVersion received_version) OVERRIDE;
  76   virtual bool OnPacketHeader(const QuicPacketHeader& header) OVERRIDE;
  77   virtual void OnPacket() OVERRIDE {}
  78   virtual void OnPublicResetPacket(
  79       const QuicPublicResetPacket& packet) OVERRIDE {}
  80   virtual void OnVersionNegotiationPacket(
  81       const QuicVersionNegotiationPacket& /*packet*/) OVERRIDE {}
  82
  83   virtual void OnPacketComplete() OVERRIDE {}
  84   // The following methods should never get called because we always return
  85   // false from OnPacketHeader(). We never need to process body of a packet.
  86   virtual void OnRevivedPacket() OVERRIDE {}
  87   virtual void OnFecProtectedPayload(base::StringPiece payload) OVERRIDE {}
  88   virtual bool OnStreamFrame(const QuicStreamFrame& frame) OVERRIDE;
  89   virtual bool OnAckFrame(const QuicAckFrame& frame) OVERRIDE;
  90   virtual bool OnCongestionFeedbackFrame(
  91       const QuicCongestionFeedbackFrame& frame) OVERRIDE;
  92   virtual bool OnRstStreamFrame(const QuicRstStreamFrame& frame) OVERRIDE;
  93   virtual bool OnConnectionCloseFrame(
  94       const QuicConnectionCloseFrame & frame) OVERRIDE;
  95   virtual bool OnGoAwayFrame(const QuicGoAwayFrame& frame) OVERRIDE;
  96   virtual void OnFecData(const QuicFecData& fec) OVERRIDE {}
  97
  98   QuicVersion version() const { return framer_.version(); }
  99
 100  protected:
 101   // Exposed for tests.
 102   bool is_write_blocked() const { return is_write_blocked_; }
 103
 104   // Decides if public reset packet should be sent for this guid based on the
 105   // number of received pacekts.
 106   bool ShouldSendPublicReset(int received_packet_count);
 107
 108   // Exposed for tests.
 109   const QuicTime::Delta time_wait_period() const { return kTimeWaitPeriod_; }
 110
 111   // Given a GUID that exists in the time wait list, returns the QuicVersion
 112   // associated with it. Used internally to set the framer version before
 113   // writing the public reset packet.
 114   QuicVersion GetQuicVersionFromGuid(QuicGuid guid);
 115
 116  private:
 117   // Stores the guid and the time it was added to time wait state.
 118   struct GuidAddTime;
 119   // Internal structure to store pending public reset packets.
 120   class QueuedPacket;
 121
 122   // Creates a public reset packet and sends it or queues it to be sent later.
 123   void SendPublicReset(const IPEndPoint& server_address,
 124                        const IPEndPoint& client_address,
 125                        QuicGuid guid,
 126                        QuicPacketSequenceNumber rejected_sequence_number);
 127
 128   // Either sends the packet and deletes it or makes pending_packets_queue_ the
 129   // owner of the packet.
 130   void SendOrQueuePacket(QueuedPacket* packet);
 131
 132   // Should only be called when write_blocked_ == false. We only care if the
 133   // writing was unsuccessful because the socket got blocked, which can be
 134   // tested using write_blocked_ == true. In case of all other errors we drop
 135   // the packet. Hence, we return void.
 136   void WriteToWire(QueuedPacket* packet);
 137
 138   // Register the alarm with the epoll server to wake up at appropriate time.
 139   void SetGuidCleanUpAlarm();
 140
 141   // A map from a recently closed guid to the number of packets received after
 142   // the termination of the connection bound to the guid.
 143   struct GuidData {
 144     GuidData(int num_packets_, QuicVersion version_)
 145         : num_packets(num_packets_), version(version_) {}
 146     int num_packets;
 147     QuicVersion version;
 148   };
 149   base::hash_map<QuicGuid, GuidData> guid_map_;
 150   typedef base::hash_map<QuicGuid, GuidData>::iterator GuidMapIterator;
 151
 152   // Maintains a list of GuidAddTime elements which it owns, in the
 153   // order they should be deleted.
 154   std::deque<GuidAddTime*> time_ordered_guid_list_;
 155
 156   // Pending public reset packets that need to be sent out to the client
 157   // when we are given a chance to write by the dispatcher.
 158   std::deque<QueuedPacket*> pending_packets_queue_;
 159
 160   // Used to parse incoming packets.
 161   QuicFramer framer_;
 162
 163   // Server and client address of the last packet processed.
 164   IPEndPoint server_address_;
 165   IPEndPoint client_address_;
 166
 167   // Used to schedule alarms to delete old guids which have been in the list for
 168   // too long. Owned by the dispatcher.
 169   EpollServer* epoll_server_;
 170
 171   // Time period for which guids should remain in time wait state.
 172   const QuicTime::Delta kTimeWaitPeriod_;
 173
 174   // Alarm registered with the epoll server to clean up guids that have out
 175   // lived their duration in time wait state.
 176   scoped_ptr<GuidCleanUpAlarm> guid_clean_up_alarm_;
 177
 178   // Clock to efficiently measure approximate time from the epoll server.
 179   QuicEpollClock clock_;
 180
 181   // Interface that writes given buffer to the socket. Owned by the dispatcher.
 182   QuicPacketWriter* writer_;
 183
 184   // True if the underlying udp socket is write blocked, i.e will return EAGAIN
 185   // on sendmsg.
 186   bool is_write_blocked_;
 187
 188   DISALLOW_COPY_AND_ASSIGN(QuicTimeWaitListManager);
 189 };
 190
 191 }  // namespace tools
 192 }  // namespace net
 193
 194 #endif  // NET_TOOLS_QUIC_QUIC_TIME_WAIT_LIST_MANAGER_H_