src/net/tools/quic/quic_time_wait_list_manager.cc

   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 #include "net/tools/quic/quic_time_wait_list_manager.h"
   6
   7 #include <errno.h>
   8
   9 #include "base/containers/hash_tables.h"
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/stl_util.h"
  12 #include "net/base/ip_endpoint.h"
  13 #include "net/quic/crypto/crypto_protocol.h"
  14 #include "net/quic/crypto/quic_decrypter.h"
  15 #include "net/quic/crypto/quic_encrypter.h"
  16 #include "net/quic/quic_clock.h"
  17 #include "net/quic/quic_framer.h"
  18 #include "net/quic/quic_protocol.h"
  19 #include "net/quic/quic_utils.h"
  20
  21 using std::make_pair;
  22
  23 namespace net {
  24 namespace tools {
  25
  26 namespace {
  27
  28 // Time period for which the guid should live in time wait state..
  29 const int kTimeWaitSeconds = 5;
  30
  31 }  // namespace
  32
  33 // A very simple alarm that just informs the QuicTimeWaitListManager to clean
  34 // up old guids. This alarm should be unregistered and deleted before the
  35 // QuicTimeWaitListManager is deleted.
  36 class GuidCleanUpAlarm : public EpollAlarm {
  37  public:
  38   explicit GuidCleanUpAlarm(QuicTimeWaitListManager* time_wait_list_manager)
  39       : time_wait_list_manager_(time_wait_list_manager) {
  40   }
  41
  42   virtual int64 OnAlarm() OVERRIDE {
  43     EpollAlarm::OnAlarm();
  44     time_wait_list_manager_->CleanUpOldGuids();
  45     // Let the time wait manager register the alarm at appropriate time.
  46     return 0;
  47   }
  48
  49  private:
  50   // Not owned.
  51   QuicTimeWaitListManager* time_wait_list_manager_;
  52 };
  53
  54 struct QuicTimeWaitListManager::GuidAddTime {
  55   GuidAddTime(QuicGuid guid, const QuicTime& time)
  56       : guid(guid),
  57         time_added(time) {
  58   }
  59
  60   QuicGuid guid;
  61   QuicTime time_added;
  62 };
  63
  64 // This class stores pending public reset packets to be sent to clients.
  65 // server_address - server address on which a packet what was received for
  66 //                  a guid in time wait state.
  67 // client_address - address of the client that sent that packet. Needed to send
  68 //                  the public reset packet back to the client.
  69 // packet - the pending public reset packet that is to be sent to the client.
  70 //          created instance takes the ownership of this packet.
  71 class QuicTimeWaitListManager::QueuedPacket {
  72  public:
  73   QueuedPacket(const IPEndPoint& server_address,
  74                const IPEndPoint& client_address,
  75                QuicEncryptedPacket* packet)
  76       : server_address_(server_address),
  77         client_address_(client_address),
  78         packet_(packet) {
  79   }
  80
  81   const IPEndPoint& server_address() const { return server_address_; }
  82   const IPEndPoint& client_address() const { return client_address_; }
  83   QuicEncryptedPacket* packet() { return packet_.get(); }
  84
  85  private:
  86   const IPEndPoint server_address_;
  87   const IPEndPoint client_address_;
  88   scoped_ptr<QuicEncryptedPacket> packet_;
  89
  90   DISALLOW_COPY_AND_ASSIGN(QueuedPacket);
  91 };
  92
  93 QuicTimeWaitListManager::QuicTimeWaitListManager(
  94     QuicPacketWriter* writer,
  95     EpollServer* epoll_server,
  96     const QuicVersionVector& supported_versions)
  97     : framer_(supported_versions,
  98               QuicTime::Zero(),  // unused
  99               true),
 100       epoll_server_(epoll_server),
 101       kTimeWaitPeriod_(QuicTime::Delta::FromSeconds(kTimeWaitSeconds)),
 102       guid_clean_up_alarm_(new GuidCleanUpAlarm(this)),
 103       clock_(epoll_server),
 104       writer_(writer),
 105       is_write_blocked_(false) {
 106   framer_.set_visitor(this);
 107   SetGuidCleanUpAlarm();
 108 }
 109
 110 QuicTimeWaitListManager::~QuicTimeWaitListManager() {
 111   guid_clean_up_alarm_->UnregisterIfRegistered();
 112   STLDeleteElements(&time_ordered_guid_list_);
 113   STLDeleteElements(&pending_packets_queue_);
 114 }
 115
 116 void QuicTimeWaitListManager::AddGuidToTimeWait(QuicGuid guid,
 117                                                 QuicVersion version) {
 118   DCHECK(!IsGuidInTimeWait(guid));
 119   // Initialize the guid with 0 packets received.
 120   GuidData data(0, version);
 121   guid_map_.insert(make_pair(guid, data));
 122   time_ordered_guid_list_.push_back(new GuidAddTime(guid,
 123                                                     clock_.ApproximateNow()));
 124 }
 125
 126 bool QuicTimeWaitListManager::IsGuidInTimeWait(QuicGuid guid) const {
 127   return guid_map_.find(guid) != guid_map_.end();
 128 }
 129
 130 void QuicTimeWaitListManager::ProcessPacket(
 131     const IPEndPoint& server_address,
 132     const IPEndPoint& client_address,
 133     QuicGuid guid,
 134     const QuicEncryptedPacket& packet) {
 135   DCHECK(IsGuidInTimeWait(guid));
 136   server_address_ = server_address;
 137   client_address_ = client_address;
 138
 139   // Set the framer to the appropriate version for this GUID, before processing.
 140   QuicVersion version = GetQuicVersionFromGuid(guid);
 141   framer_.set_version(version);
 142
 143   framer_.ProcessPacket(packet);
 144 }
 145
 146 QuicVersion QuicTimeWaitListManager::GetQuicVersionFromGuid(QuicGuid guid) {
 147   GuidMapIterator it = guid_map_.find(guid);
 148   DCHECK(it != guid_map_.end());
 149   return (it->second).version;
 150 }
 151
 152 bool QuicTimeWaitListManager::OnCanWrite() {
 153   is_write_blocked_ = false;
 154   while (!is_write_blocked_ && !pending_packets_queue_.empty()) {
 155     QueuedPacket* queued_packet = pending_packets_queue_.front();
 156     WriteToWire(queued_packet);
 157     if (!is_write_blocked_) {
 158       pending_packets_queue_.pop_front();
 159       delete queued_packet;
 160     }
 161   }
 162
 163   return !is_write_blocked_;
 164 }
 165
 166 void QuicTimeWaitListManager::OnError(QuicFramer* framer) {
 167   DLOG(INFO) << QuicUtils::ErrorToString(framer->error());
 168 }
 169
 170 bool QuicTimeWaitListManager::OnProtocolVersionMismatch(
 171     QuicVersion received_version) {
 172   // Drop such packets whose version don't match.
 173   return false;
 174 }
 175
 176 bool QuicTimeWaitListManager::OnStreamFrame(const QuicStreamFrame& frame) {
 177   return false;
 178 }
 179
 180 bool QuicTimeWaitListManager::OnAckFrame(const QuicAckFrame& frame) {
 181   return false;
 182 }
 183
 184 bool QuicTimeWaitListManager::OnCongestionFeedbackFrame(
 185     const QuicCongestionFeedbackFrame& frame) {
 186   return false;
 187 }
 188
 189 bool QuicTimeWaitListManager::OnRstStreamFrame(
 190     const QuicRstStreamFrame& frame) {
 191   return false;
 192 }
 193
 194 bool QuicTimeWaitListManager::OnConnectionCloseFrame(
 195     const QuicConnectionCloseFrame & frame) {
 196   return false;
 197 }
 198
 199 bool QuicTimeWaitListManager::OnGoAwayFrame(const QuicGoAwayFrame& frame) {
 200   return false;
 201 }
 202
 203 bool QuicTimeWaitListManager::OnPacketHeader(const QuicPacketHeader& header) {
 204   // TODO(satyamshekhar): Think about handling packets from different client
 205   // addresses.
 206   GuidMapIterator it = guid_map_.find(header.public_header.guid);
 207   DCHECK(it != guid_map_.end());
 208   // Increment the received packet count.
 209   ++((it->second).num_packets);
 210   if (ShouldSendPublicReset((it->second).num_packets)) {
 211     // We don't need the packet anymore. Just tell the client what sequence
 212     // number we rejected.
 213     SendPublicReset(server_address_,
 214                     client_address_,
 215                     header.public_header.guid,
 216                     header.packet_sequence_number);
 217   }
 218   // Never process the body of the packet in time wait state.
 219   return false;
 220 }
 221
 222 // Returns true if the number of packets received for this guid is a power of 2
 223 // to throttle the number of public reset packets we send to a client.
 224 bool QuicTimeWaitListManager::ShouldSendPublicReset(int received_packet_count) {
 225   return (received_packet_count & (received_packet_count - 1)) == 0;
 226 }
 227
 228 void QuicTimeWaitListManager::SendPublicReset(
 229     const IPEndPoint& server_address,
 230     const IPEndPoint& client_address,
 231     QuicGuid guid,
 232     QuicPacketSequenceNumber rejected_sequence_number) {
 233   QuicPublicResetPacket packet;
 234   packet.public_header.guid = guid;
 235   packet.public_header.reset_flag = true;
 236   packet.public_header.version_flag = false;
 237   packet.rejected_sequence_number = rejected_sequence_number;
 238   // TODO(satyamshekhar): generate a valid nonce for this guid.
 239   packet.nonce_proof = 1010101;
 240   QueuedPacket* queued_packet = new QueuedPacket(
 241       server_address,
 242       client_address,
 243       framer_.BuildPublicResetPacket(packet));
 244   // Takes ownership of the packet.
 245   SendOrQueuePacket(queued_packet);
 246 }
 247
 248 // Either sends the packet and deletes it or makes pending queue the
 249 // owner of the packet.
 250 void QuicTimeWaitListManager::SendOrQueuePacket(QueuedPacket* packet) {
 251   if (!is_write_blocked_) {
 252     // TODO(satyamshekhar): Handle packets that fail due to error other than
 253     // EAGAIN or EWOULDBLOCK.
 254     WriteToWire(packet);
 255   }
 256
 257   if (is_write_blocked_) {
 258     // pending_packets_queue takes the ownership of the queued packet.
 259     pending_packets_queue_.push_back(packet);
 260   } else {
 261     delete packet;
 262   }
 263 }
 264
 265 void QuicTimeWaitListManager::WriteToWire(QueuedPacket* queued_packet) {
 266   DCHECK(!is_write_blocked_);
 267   WriteResult result = writer_->WritePacket(
 268       queued_packet->packet()->data(),
 269       queued_packet->packet()->length(),
 270       queued_packet->server_address().address(),
 271       queued_packet->client_address(),
 272       this);
 273
 274   if (result.status == WRITE_STATUS_BLOCKED) {
 275     is_write_blocked_ = true;
 276   } else if (result.status == WRITE_STATUS_ERROR) {
 277     LOG(WARNING) << "Received unknown error while sending reset packet to "
 278                  << queued_packet->client_address().ToString() << ": "
 279                  << strerror(result.error_code);
 280   }
 281 }
 282
 283 void QuicTimeWaitListManager::SetGuidCleanUpAlarm() {
 284   guid_clean_up_alarm_->UnregisterIfRegistered();
 285   int64 next_alarm_interval;
 286   if (!time_ordered_guid_list_.empty()) {
 287     GuidAddTime* oldest_guid = time_ordered_guid_list_.front();
 288     QuicTime now = clock_.ApproximateNow();
 289     DCHECK(now.Subtract(oldest_guid->time_added) < kTimeWaitPeriod_);
 290     next_alarm_interval = oldest_guid->time_added
 291         .Add(kTimeWaitPeriod_)
 292         .Subtract(now)
 293         .ToMicroseconds();
 294   } else {
 295     // No guids added so none will expire before kTimeWaitPeriod_.
 296     next_alarm_interval = kTimeWaitPeriod_.ToMicroseconds();
 297   }
 298
 299   epoll_server_->RegisterAlarmApproximateDelta(next_alarm_interval,
 300                                                guid_clean_up_alarm_.get());
 301 }
 302
 303 void QuicTimeWaitListManager::CleanUpOldGuids() {
 304   QuicTime now = clock_.ApproximateNow();
 305   while (time_ordered_guid_list_.size() > 0) {
 306     DCHECK_EQ(time_ordered_guid_list_.size(), guid_map_.size());
 307     GuidAddTime* oldest_guid = time_ordered_guid_list_.front();
 308     if (now.Subtract(oldest_guid->time_added) < kTimeWaitPeriod_) {
 309       break;
 310     }
 311     // This guid has lived its age, retire it now.
 312     guid_map_.erase(oldest_guid->guid);
 313     time_ordered_guid_list_.pop_front();
 314     delete oldest_guid;
 315   }
 316   SetGuidCleanUpAlarm();
 317 }
 318
 319 }  // namespace tools
 320 }  // namespace net