net/quic/quic_dispatcher.cc

   1 // Copyright 2014 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/quic/quic_dispatcher.h"
   6
   7 #include <errno.h>
   8
   9 #include "base/debug/stack_trace.h"
  10 #include "base/logging.h"
  11 #include "base/stl_util.h"
  12 #include "net/quic/quic_blocked_writer_interface.h"
  13 #include "net/quic/quic_connection_helper.h"
  14 #include "net/quic/quic_flags.h"
  15 #include "net/quic/quic_per_connection_packet_writer.h"
  16 #include "net/quic/quic_time_wait_list_manager.h"
  17 #include "net/quic/quic_utils.h"
  18
  19 namespace net {
  20
  21 using base::StringPiece;
  22 using std::make_pair;
  23 using std::find;
  24
  25 class DeleteSessionsAlarm : public QuicAlarm::Delegate {
  26  public:
  27   explicit DeleteSessionsAlarm(QuicDispatcher* dispatcher)
  28       : dispatcher_(dispatcher) {
  29   }
  30
  31   QuicTime OnAlarm() override {
  32     dispatcher_->DeleteSessions();
  33     return QuicTime::Zero();
  34   }
  35
  36  private:
  37   QuicDispatcher* dispatcher_;
  38 };
  39
  40 class QuicDispatcher::QuicFramerVisitor : public QuicFramerVisitorInterface {
  41  public:
  42   explicit QuicFramerVisitor(QuicDispatcher* dispatcher)
  43       : dispatcher_(dispatcher),
  44         connection_id_(0) {}
  45
  46   // QuicFramerVisitorInterface implementation
  47   void OnPacket() override {}
  48   bool OnUnauthenticatedPublicHeader(
  49       const QuicPacketPublicHeader& header) override {
  50     connection_id_ = header.connection_id;
  51     return dispatcher_->OnUnauthenticatedPublicHeader(header);
  52   }
  53   bool OnUnauthenticatedHeader(const QuicPacketHeader& header) override {
  54     dispatcher_->OnUnauthenticatedHeader(header);
  55     return false;
  56   }
  57   void OnError(QuicFramer* framer) override {
  58     DVLOG(1) << QuicUtils::ErrorToString(framer->error());
  59   }
  60
  61   bool OnProtocolVersionMismatch(QuicVersion /*received_version*/) override {
  62     if (dispatcher_->time_wait_list_manager()->IsConnectionIdInTimeWait(
  63             connection_id_)) {
  64       // Keep processing after protocol mismatch - this will be dealt with by
  65       // the TimeWaitListManager.
  66       return true;
  67     } else {
  68       DLOG(DFATAL) << "Version mismatch, connection ID (" << connection_id_
  69                    << ") not in time wait list.";
  70       return false;
  71     }
  72   }
  73
  74   // The following methods should never get called because we always return
  75   // false from OnUnauthenticatedHeader().  As a result, we never process the
  76   // payload of the packet.
  77   void OnPublicResetPacket(const QuicPublicResetPacket& /*packet*/) override {
  78     DCHECK(false);
  79   }
  80   void OnVersionNegotiationPacket(
  81       const QuicVersionNegotiationPacket& /*packet*/) override {
  82     DCHECK(false);
  83   }
  84   void OnDecryptedPacket(EncryptionLevel level) override { DCHECK(false); }
  85   bool OnPacketHeader(const QuicPacketHeader& /*header*/) override {
  86     DCHECK(false);
  87     return false;
  88   }
  89   void OnRevivedPacket() override { DCHECK(false); }
  90   void OnFecProtectedPayload(StringPiece /*payload*/) override {
  91     DCHECK(false);
  92   }
  93   bool OnStreamFrame(const QuicStreamFrame& /*frame*/) override {
  94     DCHECK(false);
  95     return false;
  96   }
  97   bool OnAckFrame(const QuicAckFrame& /*frame*/) override {
  98     DCHECK(false);
  99     return false;
 100   }
 101   bool OnStopWaitingFrame(const QuicStopWaitingFrame& /*frame*/) override {
 102     DCHECK(false);
 103     return false;
 104   }
 105   bool OnPingFrame(const QuicPingFrame& /*frame*/) override {
 106     DCHECK(false);
 107     return false;
 108   }
 109   bool OnRstStreamFrame(const QuicRstStreamFrame& /*frame*/) override {
 110     DCHECK(false);
 111     return false;
 112   }
 113   bool OnConnectionCloseFrame(
 114       const QuicConnectionCloseFrame& /*frame*/) override {
 115     DCHECK(false);
 116     return false;
 117   }
 118   bool OnGoAwayFrame(const QuicGoAwayFrame& /*frame*/) override {
 119     DCHECK(false);
 120     return false;
 121   }
 122   bool OnWindowUpdateFrame(const QuicWindowUpdateFrame& /*frame*/) override {
 123     DCHECK(false);
 124     return false;
 125   }
 126   bool OnBlockedFrame(const QuicBlockedFrame& frame) override {
 127     DCHECK(false);
 128     return false;
 129   }
 130   void OnFecData(const QuicFecData& /*fec*/) override { DCHECK(false); }
 131   void OnPacketComplete() override { DCHECK(false); }
 132
 133  private:
 134   QuicDispatcher* dispatcher_;
 135
 136   // Latched in OnUnauthenticatedPublicHeader for use later.
 137   QuicConnectionId connection_id_;
 138 };
 139
 140 QuicPacketWriter* QuicDispatcher::DefaultPacketWriterFactory::Create(
 141     QuicServerPacketWriter* writer,
 142     QuicConnection* connection) {
 143   return new QuicPerConnectionPacketWriter(writer, connection);
 144 }
 145
 146 QuicDispatcher::PacketWriterFactoryAdapter::PacketWriterFactoryAdapter(
 147     QuicDispatcher* dispatcher)
 148     : dispatcher_(dispatcher) {}
 149
 150 QuicDispatcher::PacketWriterFactoryAdapter::~PacketWriterFactoryAdapter() {}
 151
 152 QuicPacketWriter* QuicDispatcher::PacketWriterFactoryAdapter::Create(
 153     QuicConnection* connection) const {
 154   return dispatcher_->packet_writer_factory_->Create(
 155       dispatcher_->writer_.get(),
 156       connection);
 157 }
 158
 159 QuicDispatcher::QuicDispatcher(const QuicConfig& config,
 160                                const QuicCryptoServerConfig& crypto_config,
 161                                const QuicVersionVector& supported_versions,
 162                                PacketWriterFactory* packet_writer_factory,
 163                                QuicConnectionHelperInterface* helper)
 164     : config_(config),
 165       crypto_config_(crypto_config),
 166       helper_(helper),
 167       delete_sessions_alarm_(
 168           helper_->CreateAlarm(new DeleteSessionsAlarm(this))),
 169       packet_writer_factory_(packet_writer_factory),
 170       connection_writer_factory_(this),
 171       supported_versions_(supported_versions),
 172       current_packet_(nullptr),
 173       framer_(supported_versions,
 174               /*unused*/ QuicTime::Zero(),
 175               Perspective::IS_SERVER),
 176       framer_visitor_(new QuicFramerVisitor(this)) {
 177   framer_.set_visitor(framer_visitor_.get());
 178 }
 179
 180 QuicDispatcher::~QuicDispatcher() {
 181   STLDeleteValues(&session_map_);
 182   STLDeleteElements(&closed_session_list_);
 183 }
 184
 185 void QuicDispatcher::Initialize(QuicServerPacketWriter* writer) {
 186   DCHECK(writer_ == nullptr);
 187   writer_.reset(writer);
 188   time_wait_list_manager_.reset(CreateQuicTimeWaitListManager());
 189 }
 190
 191 void QuicDispatcher::ProcessPacket(const IPEndPoint& server_address,
 192                                    const IPEndPoint& client_address,
 193                                    const QuicEncryptedPacket& packet) {
 194   current_server_address_ = server_address;
 195   current_client_address_ = client_address;
 196   current_packet_ = &packet;
 197   // ProcessPacket will cause the packet to be dispatched in
 198   // OnUnauthenticatedPublicHeader, or sent to the time wait list manager
 199   // in OnAuthenticatedHeader.
 200   framer_.ProcessPacket(packet);
 201   // TODO(rjshade): Return a status describing if/why a packet was dropped,
 202   //                and log somehow.  Maybe expose as a varz.
 203 }
 204
 205 bool QuicDispatcher::OnUnauthenticatedPublicHeader(
 206     const QuicPacketPublicHeader& header) {
 207   // Port zero is only allowed for unidirectional UDP, so is disallowed by QUIC.
 208   // Given that we can't even send a reply rejecting the packet, just black hole
 209   // it.
 210   if (current_client_address_.port() == 0) {
 211     return false;
 212   }
 213
 214   // The session that we have identified as the one to which this packet
 215   // belongs.
 216   QuicSession* session = nullptr;
 217   QuicConnectionId connection_id = header.connection_id;
 218   SessionMap::iterator it = session_map_.find(connection_id);
 219   if (it == session_map_.end()) {
 220     if (time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id)) {
 221       return HandlePacketForTimeWait(header);
 222     }
 223
 224     // The packet has an unknown connection ID.
 225     // If the packet is a public reset, there is nothing we must do or can do.
 226     if (header.reset_flag) {
 227       return false;
 228     }
 229
 230     // All packets within a connection sent by a client before receiving a
 231     // response from the server are required to have the version negotiation
 232     // flag set.  Since this may be a client continuing a connection we lost
 233     // track of via server restart, send a rejection to fast-fail the
 234     // connection.
 235     if (!header.version_flag) {
 236       DVLOG(1) << "Packet without version arrived for unknown connection ID "
 237                << connection_id;
 238       // Add this connection_id fo the time-wait state, to safely reject future
 239       // packets.
 240       QuicVersion version = supported_versions_.front();
 241       time_wait_list_manager_->AddConnectionIdToTimeWait(connection_id, version,
 242                                                          nullptr);
 243       DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id));
 244       return HandlePacketForTimeWait(header);
 245     }
 246
 247     session = AdditionalValidityChecksThenCreateSession(header, connection_id);
 248     if (session == nullptr) {
 249       return false;
 250     }
 251   } else {
 252     session = it->second;
 253   }
 254
 255   session->connection()->ProcessUdpPacket(
 256       current_server_address_, current_client_address_, *current_packet_);
 257
 258   // Do not parse the packet further.  The session methods called above have
 259   // processed it completely.
 260   return false;
 261 }
 262
 263 QuicSession* QuicDispatcher::AdditionalValidityChecksThenCreateSession(
 264     const QuicPacketPublicHeader& header,
 265     QuicConnectionId connection_id) {
 266   QuicSession* session = CreateQuicSession(
 267       connection_id, current_server_address_, current_client_address_);
 268
 269   if (session == nullptr) {
 270     DVLOG(1) << "Failed to create session for " << connection_id;
 271
 272     if (!framer_.IsSupportedVersion(header.versions.front())) {
 273       // TODO(ianswett): Produce packet saying "no supported version".
 274       return nullptr;
 275     }
 276
 277     // Add this connection_id to the time-wait state, to safely reject future
 278     // packets.
 279     QuicVersion version = header.versions.front();
 280     time_wait_list_manager_->AddConnectionIdToTimeWait(connection_id, version,
 281                                                        nullptr);
 282     DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id));
 283     HandlePacketForTimeWait(header);
 284
 285     return nullptr;
 286   }
 287
 288   DVLOG(1) << "Created new session for connection ID " << connection_id;
 289   session_map_.insert(std::make_pair(connection_id, session));
 290
 291   return session;
 292 }
 293
 294 void QuicDispatcher::OnUnauthenticatedHeader(const QuicPacketHeader& header) {
 295   DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(
 296       header.public_header.connection_id));
 297   time_wait_list_manager_->ProcessPacket(current_server_address_,
 298                                          current_client_address_,
 299                                          header.public_header.connection_id,
 300                                          header.packet_sequence_number,
 301                                          *current_packet_);
 302 }
 303
 304 void QuicDispatcher::CleanUpSession(SessionMap::iterator it) {
 305   QuicConnection* connection = it->second->connection();
 306   QuicEncryptedPacket* connection_close_packet =
 307       connection->ReleaseConnectionClosePacket();
 308   write_blocked_list_.erase(connection);
 309   time_wait_list_manager_->AddConnectionIdToTimeWait(it->first,
 310                                                      connection->version(),
 311                                                      connection_close_packet);
 312   session_map_.erase(it);
 313 }
 314
 315 void QuicDispatcher::DeleteSessions() {
 316   STLDeleteElements(&closed_session_list_);
 317 }
 318
 319 void QuicDispatcher::OnCanWrite() {
 320   // We finished a write: the socket should not be blocked.
 321   writer_->SetWritable();
 322
 323   // Give all the blocked writers one chance to write, until we're blocked again
 324   // or there's no work left.
 325   while (!write_blocked_list_.empty() && !writer_->IsWriteBlocked()) {
 326     QuicBlockedWriterInterface* blocked_writer =
 327         write_blocked_list_.begin()->first;
 328     write_blocked_list_.erase(write_blocked_list_.begin());
 329     blocked_writer->OnCanWrite();
 330   }
 331 }
 332
 333 bool QuicDispatcher::HasPendingWrites() const {
 334   return !write_blocked_list_.empty();
 335 }
 336
 337 void QuicDispatcher::Shutdown() {
 338   while (!session_map_.empty()) {
 339     QuicSession* session = session_map_.begin()->second;
 340     session->connection()->SendConnectionClose(QUIC_PEER_GOING_AWAY);
 341     // Validate that the session removes itself from the session map on close.
 342     DCHECK(session_map_.empty() || session_map_.begin()->second != session);
 343   }
 344   DeleteSessions();
 345 }
 346
 347 void QuicDispatcher::OnConnectionClosed(QuicConnectionId connection_id,
 348                                         QuicErrorCode error) {
 349   SessionMap::iterator it = session_map_.find(connection_id);
 350   if (it == session_map_.end()) {
 351     LOG(DFATAL) << "ConnectionId " << connection_id
 352                 << " does not exist in the session map.  "
 353                 << "Error: " << QuicUtils::ErrorToString(error);
 354     LOG(DFATAL) << base::debug::StackTrace().ToString();
 355     return;
 356   }
 357   DVLOG_IF(1, error != QUIC_NO_ERROR) << "Closing connection ("
 358                                       << connection_id
 359                                       << ") due to error: "
 360                                       << QuicUtils::ErrorToString(error);
 361   if (closed_session_list_.empty()) {
 362     delete_sessions_alarm_->Set(helper_->GetClock()->ApproximateNow());
 363   }
 364   closed_session_list_.push_back(it->second);
 365   CleanUpSession(it);
 366 }
 367
 368 void QuicDispatcher::OnWriteBlocked(
 369     QuicBlockedWriterInterface* blocked_writer) {
 370   if (!writer_->IsWriteBlocked()) {
 371     LOG(DFATAL) <<
 372         "QuicDispatcher::OnWriteBlocked called when the writer is not blocked.";
 373     // Return without adding the connection to the blocked list, to avoid
 374     // infinite loops in OnCanWrite.
 375     return;
 376   }
 377   write_blocked_list_.insert(std::make_pair(blocked_writer, true));
 378 }
 379
 380 void QuicDispatcher::OnConnectionAddedToTimeWaitList(
 381     QuicConnectionId connection_id) {
 382   DVLOG(1) << "Connection " << connection_id << " added to time wait list.";
 383 }
 384
 385 void QuicDispatcher::OnConnectionRemovedFromTimeWaitList(
 386     QuicConnectionId connection_id) {
 387   DVLOG(1) << "Connection " << connection_id << " removed from time wait list.";
 388 }
 389
 390 QuicSession* QuicDispatcher::CreateQuicSession(
 391     QuicConnectionId connection_id,
 392     const IPEndPoint& server_address,
 393     const IPEndPoint& client_address) {
 394   // The QuicSession takes ownership of |connection| below.
 395   QuicConnection* connection = new QuicConnection(
 396       connection_id, client_address, helper_, connection_writer_factory_,
 397       /* owns_writer= */ true, Perspective::IS_SERVER,
 398       crypto_config_.HasProofSource(), supported_versions_);
 399
 400   QuicServerSession* session = new QuicServerSession(config_, connection, this);
 401   session->InitializeSession(crypto_config_);
 402   return session;
 403 }
 404
 405 QuicTimeWaitListManager* QuicDispatcher::CreateQuicTimeWaitListManager() {
 406   return new QuicTimeWaitListManager(
 407       writer_.get(), this, helper_, supported_versions());
 408 }
 409
 410 bool QuicDispatcher::HandlePacketForTimeWait(
 411     const QuicPacketPublicHeader& header) {
 412   if (header.reset_flag) {
 413     // Public reset packets do not have sequence numbers, so ignore the packet.
 414     return false;
 415   }
 416
 417   // Switch the framer to the correct version, so that the sequence number can
 418   // be parsed correctly.
 419   framer_.set_version(time_wait_list_manager_->GetQuicVersionFromConnectionId(
 420       header.connection_id));
 421
 422   // Continue parsing the packet to extract the sequence number.  Then
 423   // send it to the time wait manager in OnUnathenticatedHeader.
 424   return true;
 425 }
 426
 427 }  // namespace net