remoting/protocol/jingle_session.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 "remoting/protocol/jingle_session.h"
   6
   7 #include "base/bind.h"
   8 #include "base/rand_util.h"
   9 #include "base/single_thread_task_runner.h"
  10 #include "base/stl_util.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/thread_task_runner_handle.h"
  13 #include "base/time/time.h"
  14 #include "remoting/base/constants.h"
  15 #include "remoting/jingle_glue/iq_sender.h"
  16 #include "remoting/protocol/authenticator.h"
  17 #include "remoting/protocol/channel_authenticator.h"
  18 #include "remoting/protocol/channel_multiplexer.h"
  19 #include "remoting/protocol/content_description.h"
  20 #include "remoting/protocol/jingle_messages.h"
  21 #include "remoting/protocol/jingle_session_manager.h"
  22 #include "remoting/protocol/session_config.h"
  23 #include "third_party/libjingle/source/talk/p2p/base/candidate.h"
  24 #include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
  25
  26 using buzz::XmlElement;
  27
  28 namespace remoting {
  29 namespace protocol {
  30
  31 namespace {
  32 // Delay after candidate creation before sending transport-info
  33 // message. This is neccessary to be able to pack multiple candidates
  34 // into one transport-info messages. The value needs to be greater
  35 // than zero because ports are opened asynchronously in the browser
  36 // process.
  37 const int kTransportInfoSendDelayMs = 2;
  38
  39 // How long we should wait for a response from the other end. This value is used
  40 // for all requests except |transport-info|.
  41 const int kDefaultMessageTimeout = 10;
  42
  43 // During a reconnection, it usually takes longer for the peer to respond due to
  44 // pending messages in the channel from the previous session.  From experiment,
  45 // it can take up to 20s for the session to reconnect. To make it safe, setting
  46 // the timeout to 30s.
  47 const int kSessionInitiateAndAcceptTimeout = kDefaultMessageTimeout * 3;
  48
  49 // Timeout for the transport-info messages.
  50 const int kTransportInfoTimeout = 10 * 60;
  51
  52 // Name of the multiplexed channel.
  53 const char kMuxChannelName[] = "mux";
  54
  55 ErrorCode AuthRejectionReasonToErrorCode(
  56     Authenticator::RejectionReason reason) {
  57   switch (reason) {
  58     case Authenticator::INVALID_CREDENTIALS:
  59       return AUTHENTICATION_FAILED;
  60     case Authenticator::PROTOCOL_ERROR:
  61       return INCOMPATIBLE_PROTOCOL;
  62   }
  63   NOTREACHED();
  64   return UNKNOWN_ERROR;
  65 }
  66
  67 }  // namespace
  68
  69 JingleSession::JingleSession(JingleSessionManager* session_manager)
  70     : session_manager_(session_manager),
  71       event_handler_(NULL),
  72       state_(INITIALIZING),
  73       error_(OK),
  74       config_is_set_(false),
  75       weak_factory_(this) {
  76 }
  77
  78 JingleSession::~JingleSession() {
  79   channel_multiplexer_.reset();
  80   STLDeleteContainerPointers(pending_requests_.begin(),
  81                              pending_requests_.end());
  82   STLDeleteContainerPointers(transport_info_requests_.begin(),
  83                              transport_info_requests_.end());
  84   STLDeleteContainerPairSecondPointers(channels_.begin(), channels_.end());
  85   session_manager_->SessionDestroyed(this);
  86 }
  87
  88 void JingleSession::SetEventHandler(Session::EventHandler* event_handler) {
  89   DCHECK(CalledOnValidThread());
  90   DCHECK(event_handler);
  91   event_handler_ = event_handler;
  92 }
  93
  94 ErrorCode JingleSession::error() {
  95   DCHECK(CalledOnValidThread());
  96   return error_;
  97 }
  98
  99 void JingleSession::StartConnection(
 100     const std::string& peer_jid,
 101     scoped_ptr<Authenticator> authenticator,
 102     scoped_ptr<CandidateSessionConfig> config) {
 103   DCHECK(CalledOnValidThread());
 104   DCHECK(authenticator.get());
 105   DCHECK_EQ(authenticator->state(), Authenticator::MESSAGE_READY);
 106
 107   peer_jid_ = peer_jid;
 108   authenticator_ = authenticator.Pass();
 109   candidate_config_ = config.Pass();
 110
 111   // Generate random session ID. There are usually not more than 1
 112   // concurrent session per host, so a random 64-bit integer provides
 113   // enough entropy. In the worst case connection will fail when two
 114   // clients generate the same session ID concurrently.
 115   session_id_ = base::Int64ToString(base::RandGenerator(kint64max));
 116
 117   // Send session-initiate message.
 118   JingleMessage message(peer_jid_, JingleMessage::SESSION_INITIATE,
 119                         session_id_);
 120   message.initiator = session_manager_->signal_strategy_->GetLocalJid();
 121   message.description.reset(
 122       new ContentDescription(candidate_config_->Clone(),
 123                              authenticator_->GetNextMessage()));
 124   SendMessage(message);
 125
 126   SetState(CONNECTING);
 127 }
 128
 129 void JingleSession::InitializeIncomingConnection(
 130     const JingleMessage& initiate_message,
 131     scoped_ptr<Authenticator> authenticator) {
 132   DCHECK(CalledOnValidThread());
 133   DCHECK(initiate_message.description.get());
 134   DCHECK(authenticator.get());
 135   DCHECK_EQ(authenticator->state(), Authenticator::WAITING_MESSAGE);
 136
 137   peer_jid_ = initiate_message.from;
 138   authenticator_ = authenticator.Pass();
 139   session_id_ = initiate_message.sid;
 140   candidate_config_ = initiate_message.description->config()->Clone();
 141
 142   SetState(ACCEPTING);
 143 }
 144
 145 void JingleSession::AcceptIncomingConnection(
 146     const JingleMessage& initiate_message) {
 147   DCHECK(config_is_set_);
 148
 149   // Process the first authentication message.
 150   const buzz::XmlElement* first_auth_message =
 151       initiate_message.description->authenticator_message();
 152
 153   if (!first_auth_message) {
 154     CloseInternal(INCOMPATIBLE_PROTOCOL);
 155     return;
 156   }
 157
 158   DCHECK_EQ(authenticator_->state(), Authenticator::WAITING_MESSAGE);
 159   // |authenticator_| is owned, so Unretained() is safe here.
 160   authenticator_->ProcessMessage(first_auth_message, base::Bind(
 161       &JingleSession::ContinueAcceptIncomingConnection,
 162       base::Unretained(this)));
 163 }
 164
 165 void JingleSession::ContinueAcceptIncomingConnection() {
 166   DCHECK_NE(authenticator_->state(), Authenticator::PROCESSING_MESSAGE);
 167   if (authenticator_->state() == Authenticator::REJECTED) {
 168     CloseInternal(AuthRejectionReasonToErrorCode(
 169         authenticator_->rejection_reason()));
 170     return;
 171   }
 172
 173   // Send the session-accept message.
 174   JingleMessage message(peer_jid_, JingleMessage::SESSION_ACCEPT,
 175                         session_id_);
 176
 177   scoped_ptr<buzz::XmlElement> auth_message;
 178   if (authenticator_->state() == Authenticator::MESSAGE_READY)
 179     auth_message = authenticator_->GetNextMessage();
 180
 181   message.description.reset(
 182       new ContentDescription(CandidateSessionConfig::CreateFrom(config_),
 183                              auth_message.Pass()));
 184   SendMessage(message);
 185
 186   // Update state.
 187   SetState(CONNECTED);
 188
 189   if (authenticator_->state() == Authenticator::ACCEPTED) {
 190     SetState(AUTHENTICATED);
 191   } else {
 192     DCHECK_EQ(authenticator_->state(), Authenticator::WAITING_MESSAGE);
 193     if (authenticator_->started()) {
 194       SetState(AUTHENTICATING);
 195     }
 196   }
 197 }
 198
 199 const std::string& JingleSession::jid() {
 200   DCHECK(CalledOnValidThread());
 201   return peer_jid_;
 202 }
 203
 204 const CandidateSessionConfig* JingleSession::candidate_config() {
 205   DCHECK(CalledOnValidThread());
 206   return candidate_config_.get();
 207 }
 208
 209 const SessionConfig& JingleSession::config() {
 210   DCHECK(CalledOnValidThread());
 211   return config_;
 212 }
 213
 214 void JingleSession::set_config(const SessionConfig& config) {
 215   DCHECK(CalledOnValidThread());
 216   DCHECK(!config_is_set_);
 217   config_ = config;
 218   config_is_set_ = true;
 219 }
 220
 221 ChannelFactory* JingleSession::GetTransportChannelFactory() {
 222   DCHECK(CalledOnValidThread());
 223   return this;
 224 }
 225
 226 ChannelFactory* JingleSession::GetMultiplexedChannelFactory() {
 227   DCHECK(CalledOnValidThread());
 228   if (!channel_multiplexer_.get())
 229     channel_multiplexer_.reset(new ChannelMultiplexer(this, kMuxChannelName));
 230   return channel_multiplexer_.get();
 231 }
 232
 233 void JingleSession::Close() {
 234   DCHECK(CalledOnValidThread());
 235
 236   CloseInternal(OK);
 237 }
 238
 239 void JingleSession::AddPendingRemoteCandidates(Transport* channel,
 240                                                const std::string& name) {
 241   std::list<JingleMessage::NamedCandidate>::iterator it =
 242       pending_remote_candidates_.begin();
 243   while(it != pending_remote_candidates_.end()) {
 244     if (it->name == name) {
 245       channel->AddRemoteCandidate(it->candidate);
 246       it = pending_remote_candidates_.erase(it);
 247     } else {
 248       ++it;
 249     }
 250   }
 251 }
 252
 253 void JingleSession::CreateStreamChannel(
 254       const std::string& name,
 255       const StreamChannelCallback& callback) {
 256   DCHECK(!channels_[name]);
 257
 258   scoped_ptr<ChannelAuthenticator> channel_authenticator =
 259       authenticator_->CreateChannelAuthenticator();
 260   scoped_ptr<StreamTransport> channel =
 261       session_manager_->transport_factory_->CreateStreamTransport();
 262   channel->Initialize(name, this, channel_authenticator.Pass());
 263   channel->Connect(callback);
 264   AddPendingRemoteCandidates(channel.get(), name);
 265   channels_[name] = channel.release();
 266 }
 267
 268 void JingleSession::CreateDatagramChannel(
 269     const std::string& name,
 270     const DatagramChannelCallback& callback) {
 271   DCHECK(!channels_[name]);
 272
 273   scoped_ptr<ChannelAuthenticator> channel_authenticator =
 274       authenticator_->CreateChannelAuthenticator();
 275   scoped_ptr<DatagramTransport> channel =
 276       session_manager_->transport_factory_->CreateDatagramTransport();
 277   channel->Initialize(name, this, channel_authenticator.Pass());
 278   channel->Connect(callback);
 279   AddPendingRemoteCandidates(channel.get(), name);
 280   channels_[name] = channel.release();
 281 }
 282
 283 void JingleSession::CancelChannelCreation(const std::string& name) {
 284   ChannelsMap::iterator it = channels_.find(name);
 285   if (it != channels_.end() && !it->second->is_connected()) {
 286     delete it->second;
 287     DCHECK(!channels_[name]);
 288   }
 289 }
 290
 291 void JingleSession::OnTransportCandidate(Transport* transport,
 292                                          const cricket::Candidate& candidate) {
 293   pending_candidates_.push_back(JingleMessage::NamedCandidate(
 294       transport->name(), candidate));
 295
 296   if (!transport_infos_timer_.IsRunning()) {
 297     // Delay sending the new candidates in case we get more candidates
 298     // that we can send in one message.
 299     transport_infos_timer_.Start(
 300         FROM_HERE, base::TimeDelta::FromMilliseconds(kTransportInfoSendDelayMs),
 301         this, &JingleSession::SendTransportInfo);
 302   }
 303 }
 304
 305 void JingleSession::OnTransportRouteChange(Transport* transport,
 306                                            const TransportRoute& route) {
 307   if (event_handler_)
 308     event_handler_->OnSessionRouteChange(transport->name(), route);
 309 }
 310
 311 void JingleSession::OnTransportFailed(Transport* transport) {
 312   CloseInternal(CHANNEL_CONNECTION_ERROR);
 313 }
 314
 315 void JingleSession::OnTransportDeleted(Transport* transport) {
 316   ChannelsMap::iterator it = channels_.find(transport->name());
 317   DCHECK_EQ(it->second, transport);
 318   channels_.erase(it);
 319 }
 320
 321 void JingleSession::SendMessage(const JingleMessage& message) {
 322   scoped_ptr<IqRequest> request = session_manager_->iq_sender()->SendIq(
 323       message.ToXml(),
 324       base::Bind(&JingleSession::OnMessageResponse,
 325                  base::Unretained(this),
 326                  message.action));
 327
 328   int timeout = kDefaultMessageTimeout;
 329   if (message.action == JingleMessage::SESSION_INITIATE ||
 330       message.action == JingleMessage::SESSION_ACCEPT) {
 331     timeout = kSessionInitiateAndAcceptTimeout;
 332   }
 333   if (request) {
 334     request->SetTimeout(base::TimeDelta::FromSeconds(timeout));
 335     pending_requests_.insert(request.release());
 336   } else {
 337     LOG(ERROR) << "Failed to send a "
 338                << JingleMessage::GetActionName(message.action) << " message";
 339   }
 340 }
 341
 342 void JingleSession::OnMessageResponse(
 343     JingleMessage::ActionType request_type,
 344     IqRequest* request,
 345     const buzz::XmlElement* response) {
 346   std::string type_str = JingleMessage::GetActionName(request_type);
 347
 348   // Delete the request from the list of pending requests.
 349   pending_requests_.erase(request);
 350   delete request;
 351
 352   // |response| will be NULL if the request timed out.
 353   if (!response) {
 354     LOG(ERROR) << type_str << " request timed out.";
 355     CloseInternal(SIGNALING_TIMEOUT);
 356     return;
 357   } else {
 358     const std::string& type =
 359         response->Attr(buzz::QName(std::string(), "type"));
 360     if (type != "result") {
 361       LOG(ERROR) << "Received error in response to " << type_str
 362                  << " message: \"" << response->Str()
 363                  << "\". Terminating the session.";
 364
 365       switch (request_type) {
 366         case JingleMessage::SESSION_INFO:
 367           // session-info is used for the new authentication protocol,
 368           // and wasn't previously supported.
 369           CloseInternal(INCOMPATIBLE_PROTOCOL);
 370           break;
 371
 372         default:
 373           // TODO(sergeyu): There may be different reasons for error
 374           // here. Parse the response stanza to find failure reason.
 375           CloseInternal(PEER_IS_OFFLINE);
 376       }
 377     }
 378   }
 379 }
 380
 381 void JingleSession::SendTransportInfo() {
 382   JingleMessage message(peer_jid_, JingleMessage::TRANSPORT_INFO, session_id_);
 383   message.candidates.swap(pending_candidates_);
 384
 385   scoped_ptr<IqRequest> request = session_manager_->iq_sender()->SendIq(
 386       message.ToXml(),
 387       base::Bind(&JingleSession::OnTransportInfoResponse,
 388                  base::Unretained(this)));
 389   if (request) {
 390     request->SetTimeout(base::TimeDelta::FromSeconds(kTransportInfoTimeout));
 391     transport_info_requests_.push_back(request.release());
 392   } else {
 393     LOG(ERROR) << "Failed to send a transport-info message";
 394   }
 395 }
 396
 397 void JingleSession::OnTransportInfoResponse(IqRequest* request,
 398                                             const buzz::XmlElement* response) {
 399   DCHECK(!transport_info_requests_.empty());
 400
 401   // Consider transport-info requests sent before this one lost and delete
 402   // corresponding IqRequest objects.
 403   while (transport_info_requests_.front() != request) {
 404     delete transport_info_requests_.front();
 405     transport_info_requests_.pop_front();
 406   }
 407
 408   // Delete the |request| itself.
 409   DCHECK_EQ(request, transport_info_requests_.front());
 410   delete request;
 411   transport_info_requests_.pop_front();
 412
 413   // Ignore transport-info timeouts.
 414   if (!response) {
 415     LOG(ERROR) << "transport-info request has timed out.";
 416     return;
 417   }
 418
 419   const std::string& type = response->Attr(buzz::QName(std::string(), "type"));
 420   if (type != "result") {
 421     LOG(ERROR) << "Received error in response to transport-info message: \""
 422                << response->Str() << "\". Terminating the session.";
 423     CloseInternal(PEER_IS_OFFLINE);
 424   }
 425 }
 426
 427 void JingleSession::OnIncomingMessage(const JingleMessage& message,
 428                                       const ReplyCallback& reply_callback) {
 429   DCHECK(CalledOnValidThread());
 430
 431   if (message.from != peer_jid_) {
 432     // Ignore messages received from a different Jid.
 433     reply_callback.Run(JingleMessageReply::INVALID_SID);
 434     return;
 435   }
 436
 437   switch (message.action) {
 438     case JingleMessage::SESSION_ACCEPT:
 439       OnAccept(message, reply_callback);
 440       break;
 441
 442     case JingleMessage::SESSION_INFO:
 443       OnSessionInfo(message, reply_callback);
 444       break;
 445
 446     case JingleMessage::TRANSPORT_INFO:
 447       reply_callback.Run(JingleMessageReply::NONE);
 448       ProcessTransportInfo(message);
 449       break;
 450
 451     case JingleMessage::SESSION_TERMINATE:
 452       OnTerminate(message, reply_callback);
 453       break;
 454
 455     default:
 456       reply_callback.Run(JingleMessageReply::UNEXPECTED_REQUEST);
 457   }
 458 }
 459
 460 void JingleSession::OnAccept(const JingleMessage& message,
 461                              const ReplyCallback& reply_callback) {
 462   if (state_ != CONNECTING) {
 463     reply_callback.Run(JingleMessageReply::UNEXPECTED_REQUEST);
 464     return;
 465   }
 466
 467   reply_callback.Run(JingleMessageReply::NONE);
 468
 469   const buzz::XmlElement* auth_message =
 470       message.description->authenticator_message();
 471   if (!auth_message) {
 472     DLOG(WARNING) << "Received session-accept without authentication message ";
 473     CloseInternal(INCOMPATIBLE_PROTOCOL);
 474     return;
 475   }
 476
 477   if (!InitializeConfigFromDescription(message.description.get())) {
 478     CloseInternal(INCOMPATIBLE_PROTOCOL);
 479     return;
 480   }
 481
 482   // In case there is transport information in the accept message.
 483   ProcessTransportInfo(message);
 484
 485   SetState(CONNECTED);
 486
 487   DCHECK(authenticator_->state() == Authenticator::WAITING_MESSAGE);
 488   authenticator_->ProcessMessage(auth_message, base::Bind(
 489       &JingleSession::ProcessAuthenticationStep,base::Unretained(this)));
 490 }
 491
 492 void JingleSession::OnSessionInfo(const JingleMessage& message,
 493                                   const ReplyCallback& reply_callback) {
 494   if (!message.info.get() ||
 495       !Authenticator::IsAuthenticatorMessage(message.info.get())) {
 496     reply_callback.Run(JingleMessageReply::UNSUPPORTED_INFO);
 497     return;
 498   }
 499
 500   if ((state_ != CONNECTED && state_ != AUTHENTICATING) ||
 501       authenticator_->state() != Authenticator::WAITING_MESSAGE) {
 502     LOG(WARNING) << "Received unexpected authenticator message "
 503                  << message.info->Str();
 504     reply_callback.Run(JingleMessageReply::UNEXPECTED_REQUEST);
 505     CloseInternal(INCOMPATIBLE_PROTOCOL);
 506     return;
 507   }
 508
 509   reply_callback.Run(JingleMessageReply::NONE);
 510
 511   authenticator_->ProcessMessage(message.info.get(), base::Bind(
 512       &JingleSession::ProcessAuthenticationStep, base::Unretained(this)));
 513 }
 514
 515 void JingleSession::ProcessTransportInfo(const JingleMessage& message) {
 516   for (std::list<JingleMessage::NamedCandidate>::const_iterator it =
 517            message.candidates.begin();
 518        it != message.candidates.end(); ++it) {
 519     ChannelsMap::iterator channel = channels_.find(it->name);
 520     if (channel != channels_.end()) {
 521       channel->second->AddRemoteCandidate(it->candidate);
 522     } else {
 523       // Transport info was received before the channel was created.
 524       // This could happen due to messages being reordered on the wire.
 525       pending_remote_candidates_.push_back(*it);
 526     }
 527   }
 528 }
 529
 530 void JingleSession::OnTerminate(const JingleMessage& message,
 531                                 const ReplyCallback& reply_callback) {
 532   if (!is_session_active()) {
 533     LOG(WARNING) << "Received unexpected session-terminate message.";
 534     reply_callback.Run(JingleMessageReply::UNEXPECTED_REQUEST);
 535     return;
 536   }
 537
 538   reply_callback.Run(JingleMessageReply::NONE);
 539
 540   switch (message.reason) {
 541     case JingleMessage::SUCCESS:
 542       if (state_ == CONNECTING) {
 543         error_ = SESSION_REJECTED;
 544       } else {
 545         error_ = OK;
 546       }
 547       break;
 548     case JingleMessage::DECLINE:
 549       error_ = AUTHENTICATION_FAILED;
 550       break;
 551     case JingleMessage::CANCEL:
 552       error_ = HOST_OVERLOAD;
 553       break;
 554     case JingleMessage::GENERAL_ERROR:
 555       error_ = CHANNEL_CONNECTION_ERROR;
 556       break;
 557     case JingleMessage::INCOMPATIBLE_PARAMETERS:
 558       error_ = INCOMPATIBLE_PROTOCOL;
 559       break;
 560     default:
 561       error_ = UNKNOWN_ERROR;
 562   }
 563
 564   if (error_ != OK) {
 565     SetState(FAILED);
 566   } else {
 567     SetState(CLOSED);
 568   }
 569 }
 570
 571 bool JingleSession::InitializeConfigFromDescription(
 572     const ContentDescription* description) {
 573   DCHECK(description);
 574
 575   if (!description->config()->GetFinalConfig(&config_)) {
 576     LOG(ERROR) << "session-accept does not specify configuration";
 577     return false;
 578   }
 579   if (!candidate_config()->IsSupported(config_)) {
 580     LOG(ERROR) << "session-accept specifies an invalid configuration";
 581     return false;
 582   }
 583
 584   return true;
 585 }
 586
 587 void JingleSession::ProcessAuthenticationStep() {
 588   DCHECK(CalledOnValidThread());
 589   DCHECK_NE(authenticator_->state(), Authenticator::PROCESSING_MESSAGE);
 590
 591   if (state_ != CONNECTED && state_ != AUTHENTICATING) {
 592     DCHECK(state_ == FAILED || state_ == CLOSED);
 593     // The remote host closed the connection while the authentication was being
 594     // processed asynchronously, nothing to do.
 595     return;
 596   }
 597
 598   if (authenticator_->state() == Authenticator::MESSAGE_READY) {
 599     JingleMessage message(peer_jid_, JingleMessage::SESSION_INFO, session_id_);
 600     message.info = authenticator_->GetNextMessage();
 601     DCHECK(message.info.get());
 602     SendMessage(message);
 603   }
 604   DCHECK_NE(authenticator_->state(), Authenticator::MESSAGE_READY);
 605
 606   // The current JingleSession object can be destroyed by event_handler of
 607   // SetState(AUTHENTICATING) and cause subsequent dereferencing of the this
 608   // pointer to crash.  To protect against it, we run ContinueAuthenticationStep
 609   // asychronously using a weak pointer.
 610   base::ThreadTaskRunnerHandle::Get()->PostTask(
 611     FROM_HERE,
 612     base::Bind(&JingleSession::ContinueAuthenticationStep,
 613                weak_factory_.GetWeakPtr()));
 614
 615   if (authenticator_->started()) {
 616     SetState(AUTHENTICATING);
 617   }
 618 }
 619
 620 void JingleSession::ContinueAuthenticationStep() {
 621   if (authenticator_->state() == Authenticator::ACCEPTED) {
 622     SetState(AUTHENTICATED);
 623   } else if (authenticator_->state() == Authenticator::REJECTED) {
 624     CloseInternal(AuthRejectionReasonToErrorCode(
 625         authenticator_->rejection_reason()));
 626   }
 627 }
 628
 629 void JingleSession::CloseInternal(ErrorCode error) {
 630   DCHECK(CalledOnValidThread());
 631
 632   if (is_session_active()) {
 633     // Send session-terminate message with the appropriate error code.
 634     JingleMessage::Reason reason;
 635     switch (error) {
 636       case OK:
 637         reason = JingleMessage::SUCCESS;
 638         break;
 639       case SESSION_REJECTED:
 640       case AUTHENTICATION_FAILED:
 641         reason = JingleMessage::DECLINE;
 642         break;
 643       case INCOMPATIBLE_PROTOCOL:
 644         reason = JingleMessage::INCOMPATIBLE_PARAMETERS;
 645         break;
 646       case HOST_OVERLOAD:
 647         reason = JingleMessage::CANCEL;
 648         break;
 649       default:
 650         reason = JingleMessage::GENERAL_ERROR;
 651     }
 652
 653     JingleMessage message(peer_jid_, JingleMessage::SESSION_TERMINATE,
 654                           session_id_);
 655     message.reason = reason;
 656     SendMessage(message);
 657   }
 658
 659   error_ = error;
 660
 661   if (state_ != FAILED && state_ != CLOSED) {
 662     if (error != OK) {
 663       SetState(FAILED);
 664     } else {
 665       SetState(CLOSED);
 666     }
 667   }
 668 }
 669
 670 void JingleSession::SetState(State new_state) {
 671   DCHECK(CalledOnValidThread());
 672
 673   if (new_state != state_) {
 674     DCHECK_NE(state_, CLOSED);
 675     DCHECK_NE(state_, FAILED);
 676
 677     state_ = new_state;
 678     if (event_handler_)
 679       event_handler_->OnSessionStateChange(new_state);
 680   }
 681 }
 682
 683 bool JingleSession::is_session_active() {
 684   return state_ == CONNECTING || state_ == ACCEPTING || state_ == CONNECTED ||
 685         state_ == AUTHENTICATING || state_ == AUTHENTICATED;
 686 }
 687
 688 }  // namespace protocol
 689 }  // namespace remoting