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, /*unused*/ QuicTime::Zero(), true),
 174       framer_visitor_(new QuicFramerVisitor(this)) {
 175   framer_.set_visitor(framer_visitor_.get());
 176 }
 177
 178 QuicDispatcher::~QuicDispatcher() {
 179   STLDeleteValues(&session_map_);
 180   STLDeleteElements(&closed_session_list_);
 181 }
 182
 183 void QuicDispatcher::Initialize(QuicServerPacketWriter* writer) {
 184   DCHECK(writer_ == nullptr);
 185   writer_.reset(writer);
 186   time_wait_list_manager_.reset(CreateQuicTimeWaitListManager());
 187 }
 188
 189 void QuicDispatcher::ProcessPacket(const IPEndPoint& server_address,
 190                                    const IPEndPoint& client_address,
 191                                    const QuicEncryptedPacket& packet) {
 192   current_server_address_ = server_address;
 193   current_client_address_ = client_address;
 194   current_packet_ = &packet;
 195   // ProcessPacket will cause the packet to be dispatched in
 196   // OnUnauthenticatedPublicHeader, or sent to the time wait list manager
 197   // in OnAuthenticatedHeader.
 198   framer_.ProcessPacket(packet);
 199   // TODO(rjshade): Return a status describing if/why a packet was dropped,
 200   //                and log somehow.  Maybe expose as a varz.
 201 }
 202
 203 bool QuicDispatcher::OnUnauthenticatedPublicHeader(
 204     const QuicPacketPublicHeader& header) {
 205   QuicSession* session = nullptr;
 206
 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   QuicConnectionId connection_id = header.connection_id;
 215   SessionMap::iterator it = session_map_.find(connection_id);
 216   if (it == session_map_.end()) {
 217     if (header.reset_flag) {
 218       return false;
 219     }
 220     if (time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id)) {
 221       return HandlePacketForTimeWait(header);
 222     }
 223
 224     // Ensure the packet has a version negotiation bit set before creating a new
 225     // session for it.  All initial packets for a new connection are required to
 226     // have the flag set.  Otherwise it may be a stray packet.
 227     if (header.version_flag) {
 228       session = CreateQuicSession(connection_id, current_server_address_,
 229                                   current_client_address_);
 230     }
 231
 232     if (session == nullptr) {
 233       DVLOG(1) << "Failed to create session for " << connection_id;
 234       // Add this connection_id fo the time-wait state, to safely reject future
 235       // packets.
 236
 237       if (header.version_flag &&
 238           !framer_.IsSupportedVersion(header.versions.front())) {
 239         // TODO(ianswett): Produce a no-version version negotiation packet.
 240         return false;
 241       }
 242
 243       // Use the version in the packet if possible, otherwise assume the latest.
 244       QuicVersion version = header.version_flag ? header.versions.front() :
 245           supported_versions_.front();
 246       time_wait_list_manager_->AddConnectionIdToTimeWait(connection_id, version,
 247                                                          nullptr);
 248       DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(connection_id));
 249       return HandlePacketForTimeWait(header);
 250     }
 251     DVLOG(1) << "Created new session for " << connection_id;
 252     session_map_.insert(std::make_pair(connection_id, session));
 253   } else {
 254     session = it->second;
 255   }
 256
 257   session->connection()->ProcessUdpPacket(
 258       current_server_address_, current_client_address_, *current_packet_);
 259
 260   // Do not parse the packet further.  The session will process it completely.
 261   return false;
 262 }
 263
 264 void QuicDispatcher::OnUnauthenticatedHeader(const QuicPacketHeader& header) {
 265   DCHECK(time_wait_list_manager_->IsConnectionIdInTimeWait(
 266       header.public_header.connection_id));
 267   time_wait_list_manager_->ProcessPacket(current_server_address_,
 268                                          current_client_address_,
 269                                          header.public_header.connection_id,
 270                                          header.packet_sequence_number,
 271                                          *current_packet_);
 272 }
 273
 274 void QuicDispatcher::CleanUpSession(SessionMap::iterator it) {
 275   QuicConnection* connection = it->second->connection();
 276   QuicEncryptedPacket* connection_close_packet =
 277       connection->ReleaseConnectionClosePacket();
 278   write_blocked_list_.erase(connection);
 279   time_wait_list_manager_->AddConnectionIdToTimeWait(it->first,
 280                                                      connection->version(),
 281                                                      connection_close_packet);
 282   session_map_.erase(it);
 283 }
 284
 285 void QuicDispatcher::DeleteSessions() {
 286   STLDeleteElements(&closed_session_list_);
 287 }
 288
 289 void QuicDispatcher::OnCanWrite() {
 290   // We finished a write: the socket should not be blocked.
 291   writer_->SetWritable();
 292
 293   // Give all the blocked writers one chance to write, until we're blocked again
 294   // or there's no work left.
 295   while (!write_blocked_list_.empty() && !writer_->IsWriteBlocked()) {
 296     QuicBlockedWriterInterface* blocked_writer =
 297         write_blocked_list_.begin()->first;
 298     write_blocked_list_.erase(write_blocked_list_.begin());
 299     blocked_writer->OnCanWrite();
 300   }
 301 }
 302
 303 bool QuicDispatcher::HasPendingWrites() const {
 304   return !write_blocked_list_.empty();
 305 }
 306
 307 void QuicDispatcher::Shutdown() {
 308   while (!session_map_.empty()) {
 309     QuicSession* session = session_map_.begin()->second;
 310     session->connection()->SendConnectionClose(QUIC_PEER_GOING_AWAY);
 311     // Validate that the session removes itself from the session map on close.
 312     DCHECK(session_map_.empty() || session_map_.begin()->second != session);
 313   }
 314   DeleteSessions();
 315 }
 316
 317 void QuicDispatcher::OnConnectionClosed(QuicConnectionId connection_id,
 318                                         QuicErrorCode error) {
 319   SessionMap::iterator it = session_map_.find(connection_id);
 320   if (it == session_map_.end()) {
 321     LOG(DFATAL) << "ConnectionId " << connection_id
 322                 << " does not exist in the session map.  "
 323                 << "Error: " << QuicUtils::ErrorToString(error);
 324     LOG(DFATAL) << base::debug::StackTrace().ToString();
 325     return;
 326   }
 327   DVLOG_IF(1, error != QUIC_NO_ERROR) << "Closing connection ("
 328                                       << connection_id
 329                                       << ") due to error: "
 330                                       << QuicUtils::ErrorToString(error);
 331   if (closed_session_list_.empty()) {
 332     delete_sessions_alarm_->Set(helper_->GetClock()->ApproximateNow());
 333   }
 334   closed_session_list_.push_back(it->second);
 335   CleanUpSession(it);
 336 }
 337
 338 void QuicDispatcher::OnWriteBlocked(
 339     QuicBlockedWriterInterface* blocked_writer) {
 340   if (!writer_->IsWriteBlocked()) {
 341     LOG(DFATAL) <<
 342         "QuicDispatcher::OnWriteBlocked called when the writer is not blocked.";
 343     // Return without adding the connection to the blocked list, to avoid
 344     // infinite loops in OnCanWrite.
 345     return;
 346   }
 347   write_blocked_list_.insert(std::make_pair(blocked_writer, true));
 348 }
 349
 350 void QuicDispatcher::OnConnectionAddedToTimeWaitList(
 351     QuicConnectionId connection_id) {
 352   DVLOG(1) << "Connection " << connection_id << " added to time wait list.";
 353 }
 354
 355 void QuicDispatcher::OnConnectionRemovedFromTimeWaitList(
 356     QuicConnectionId connection_id) {
 357   DVLOG(1) << "Connection " << connection_id << " removed from time wait list.";
 358 }
 359
 360 QuicSession* QuicDispatcher::CreateQuicSession(
 361     QuicConnectionId connection_id,
 362     const IPEndPoint& server_address,
 363     const IPEndPoint& client_address) {
 364   // The QuicSession takes ownership of |connection| below.
 365   QuicConnection* connection = new QuicConnection(
 366       connection_id, client_address, helper_, connection_writer_factory_,
 367       /* owns_writer= */ true, /* is_server= */ true,
 368       crypto_config_.HasProofSource(), supported_versions_);
 369
 370   QuicServerSession* session = new QuicServerSession(config_, connection, this);
 371   session->InitializeSession(crypto_config_);
 372   return session;
 373 }
 374
 375 QuicTimeWaitListManager* QuicDispatcher::CreateQuicTimeWaitListManager() {
 376   return new QuicTimeWaitListManager(
 377       writer_.get(), this, helper_, supported_versions());
 378 }
 379
 380 bool QuicDispatcher::HandlePacketForTimeWait(
 381     const QuicPacketPublicHeader& header) {
 382   if (header.reset_flag) {
 383     // Public reset packets do not have sequence numbers, so ignore the packet.
 384     return false;
 385   }
 386
 387   // Switch the framer to the correct version, so that the sequence number can
 388   // be parsed correctly.
 389   framer_.set_version(time_wait_list_manager_->GetQuicVersionFromConnectionId(
 390       header.connection_id));
 391
 392   // Continue parsing the packet to extract the sequence number.  Then
 393   // send it to the time wait manager in OnUnathenticatedHeader.
 394   return true;
 395 }
 396
 397 }  // namespace net