remoting/host/heartbeat_sender.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/host/heartbeat_sender.h"
   6
   7 #include <math.h>
   8
   9 #include "base/bind.h"
  10 #include "base/rand_util.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/stringize_macros.h"
  13 #include "base/thread_task_runner_handle.h"
  14 #include "base/time/time.h"
  15 #include "remoting/base/constants.h"
  16 #include "remoting/base/logging.h"
  17 #include "remoting/host/server_log_entry_host.h"
  18 #include "remoting/signaling/iq_sender.h"
  19 #include "remoting/signaling/server_log_entry.h"
  20 #include "remoting/signaling/signal_strategy.h"
  21 #include "third_party/webrtc/libjingle/xmllite/xmlelement.h"
  22 #include "third_party/webrtc/libjingle/xmpp/constants.h"
  23
  24 using buzz::QName;
  25 using buzz::XmlElement;
  26
  27 namespace remoting {
  28
  29 namespace {
  30
  31 const char kHeartbeatQueryTag[] = "heartbeat";
  32 const char kHostIdAttr[] = "hostid";
  33 const char kHostVersionTag[] = "host-version";
  34 const char kHeartbeatSignatureTag[] = "signature";
  35 const char kSequenceIdAttr[] = "sequence-id";
  36 const char kHostOfflineReasonAttr[] = "host-offline-reason";
  37
  38 const char kErrorTag[] = "error";
  39 const char kNotFoundTag[] = "item-not-found";
  40
  41 const char kHeartbeatResultTag[] = "heartbeat-result";
  42 const char kSetIntervalTag[] = "set-interval";
  43 const char kExpectedSequenceIdTag[] = "expected-sequence-id";
  44
  45 const int64 kDefaultHeartbeatIntervalMs = 5 * 60 * 1000;  // 5 minutes.
  46 const int64 kResendDelayMs = 10 * 1000;  // 10 seconds.
  47 const int64 kResendDelayOnHostNotFoundMs = 10 * 1000; // 10 seconds.
  48 const int kMaxResendOnHostNotFoundCount = 12;  // 2 minutes (12 x 10 seconds).
  49
  50 }  // namespace
  51
  52 HeartbeatSender::HeartbeatSender(
  53     const base::Closure& on_heartbeat_successful_callback,
  54     const base::Closure& on_unknown_host_id_error,
  55     const std::string& host_id,
  56     SignalStrategy* signal_strategy,
  57     const scoped_refptr<const RsaKeyPair>& host_key_pair,
  58     const std::string& directory_bot_jid)
  59     : on_heartbeat_successful_callback_(on_heartbeat_successful_callback),
  60       on_unknown_host_id_error_(on_unknown_host_id_error),
  61       host_id_(host_id),
  62       signal_strategy_(signal_strategy),
  63       host_key_pair_(host_key_pair),
  64       directory_bot_jid_(directory_bot_jid),
  65       interval_ms_(kDefaultHeartbeatIntervalMs),
  66       sequence_id_(0),
  67       sequence_id_was_set_(false),
  68       sequence_id_recent_set_num_(0),
  69       heartbeat_succeeded_(false),
  70       failed_startup_heartbeat_count_(0) {
  71   DCHECK(signal_strategy_);
  72   DCHECK(host_key_pair_.get());
  73   DCHECK(thread_checker_.CalledOnValidThread());
  74
  75   signal_strategy_->AddListener(this);
  76
  77   // Start heartbeats if the |signal_strategy_| is already connected.
  78   OnSignalStrategyStateChange(signal_strategy_->GetState());
  79 }
  80
  81 HeartbeatSender::~HeartbeatSender() {
  82   signal_strategy_->RemoveListener(this);
  83 }
  84
  85 void HeartbeatSender::OnSignalStrategyStateChange(SignalStrategy::State state) {
  86   DCHECK(thread_checker_.CalledOnValidThread());
  87   if (state == SignalStrategy::CONNECTED) {
  88     iq_sender_.reset(new IqSender(signal_strategy_));
  89     SendStanza();
  90     timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(interval_ms_),
  91                  this, &HeartbeatSender::SendStanza);
  92   } else if (state == SignalStrategy::DISCONNECTED) {
  93     request_.reset();
  94     iq_sender_.reset();
  95     timer_.Stop();
  96     timer_resend_.Stop();
  97   }
  98 }
  99
 100 bool HeartbeatSender::OnSignalStrategyIncomingStanza(
 101     const buzz::XmlElement* stanza) {
 102   return false;
 103 }
 104
 105 void HeartbeatSender::OnHostOfflineReasonTimeout() {
 106   DCHECK(!host_offline_reason_ack_callback_.is_null());
 107
 108   base::Callback<void(bool)> local_callback = host_offline_reason_ack_callback_;
 109   host_offline_reason_ack_callback_.Reset();
 110   local_callback.Run(false);
 111 }
 112
 113 void HeartbeatSender::OnHostOfflineReasonAck() {
 114   if (host_offline_reason_ack_callback_.is_null()) {
 115     DCHECK(!host_offline_reason_timeout_timer_.IsRunning());
 116     return;
 117   }
 118
 119   DCHECK(host_offline_reason_timeout_timer_.IsRunning());
 120   host_offline_reason_timeout_timer_.Stop();
 121
 122   // Run the ACK callback under a clean stack via PostTask() (because the
 123   // callback can end up deleting |this| HeartbeatSender [i.e. when used from
 124   // HostSignalingManager]).
 125   base::Closure fully_bound_ack_callback =
 126       base::Bind(host_offline_reason_ack_callback_, true);
 127   host_offline_reason_ack_callback_.Reset();
 128   base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
 129                                                 fully_bound_ack_callback);
 130 }
 131
 132 void HeartbeatSender::SetHostOfflineReason(
 133     const std::string& host_offline_reason,
 134     const base::TimeDelta& timeout,
 135     const base::Callback<void(bool success)>& ack_callback) {
 136   DCHECK(thread_checker_.CalledOnValidThread());
 137   DCHECK(host_offline_reason_ack_callback_.is_null());
 138   host_offline_reason_ = host_offline_reason;
 139   host_offline_reason_ack_callback_ = ack_callback;
 140   host_offline_reason_timeout_timer_.Start(
 141       FROM_HERE, timeout, this, &HeartbeatSender::OnHostOfflineReasonTimeout);
 142   if (signal_strategy_->GetState() == SignalStrategy::CONNECTED) {
 143     DoSendStanza();
 144   }
 145 }
 146
 147 void HeartbeatSender::SendStanza() {
 148   // Make sure we don't send another heartbeat before the heartbeat interval
 149   // has expired.
 150   timer_resend_.Stop();
 151   DoSendStanza();
 152 }
 153
 154 void HeartbeatSender::ResendStanza() {
 155   // Make sure we don't send another heartbeat before the heartbeat interval
 156   // has expired.
 157   timer_.Reset();
 158   DoSendStanza();
 159 }
 160
 161 void HeartbeatSender::DoSendStanza() {
 162   DCHECK(thread_checker_.CalledOnValidThread());
 163   DCHECK(signal_strategy_->GetState() == SignalStrategy::CONNECTED);
 164   VLOG(1) << "Sending heartbeat stanza to " << directory_bot_jid_;
 165
 166   request_ = iq_sender_->SendIq(
 167       buzz::STR_SET, directory_bot_jid_, CreateHeartbeatMessage(),
 168       base::Bind(&HeartbeatSender::ProcessResponse,
 169                  base::Unretained(this),
 170                  !host_offline_reason_.empty()));
 171   ++sequence_id_;
 172 }
 173
 174 void HeartbeatSender::ProcessResponse(
 175     bool is_offline_heartbeat_response,
 176     IqRequest* request,
 177     const XmlElement* response) {
 178   DCHECK(thread_checker_.CalledOnValidThread());
 179
 180   std::string type = response->Attr(buzz::QN_TYPE);
 181   if (type == buzz::STR_ERROR) {
 182     const XmlElement* error_element =
 183         response->FirstNamed(QName(buzz::NS_CLIENT, kErrorTag));
 184     if (error_element) {
 185       if (error_element->FirstNamed(QName(buzz::NS_STANZA, kNotFoundTag))) {
 186         LOG(ERROR) << "Received error: Host ID not found";
 187         // If the host was registered immediately before it sends a heartbeat,
 188         // then server-side latency may prevent the server recognizing the
 189         // host ID in the heartbeat. So even if all of the first few heartbeats
 190         // get a "host ID not found" error, that's not a good enough reason to
 191         // exit.
 192         failed_startup_heartbeat_count_++;
 193         if (!heartbeat_succeeded_ && (failed_startup_heartbeat_count_ <=
 194                 kMaxResendOnHostNotFoundCount)) {
 195           timer_resend_.Start(FROM_HERE,
 196                               base::TimeDelta::FromMilliseconds(
 197                                   kResendDelayOnHostNotFoundMs),
 198                               this,
 199                               &HeartbeatSender::ResendStanza);
 200           return;
 201         }
 202         on_unknown_host_id_error_.Run();
 203         return;
 204       }
 205     }
 206
 207     LOG(ERROR) << "Received error in response to heartbeat: "
 208                << response->Str();
 209     return;
 210   }
 211
 212   // This method must only be called for error or result stanzas.
 213   DCHECK_EQ(std::string(buzz::STR_RESULT), type);
 214
 215   const XmlElement* result_element =
 216       response->FirstNamed(QName(kChromotingXmlNamespace, kHeartbeatResultTag));
 217   if (result_element) {
 218     const XmlElement* set_interval_element =
 219         result_element->FirstNamed(QName(kChromotingXmlNamespace,
 220                                          kSetIntervalTag));
 221     if (set_interval_element) {
 222       const std::string& interval_str = set_interval_element->BodyText();
 223       int interval;
 224       if (!base::StringToInt(interval_str, &interval) || interval <= 0) {
 225         LOG(ERROR) << "Received invalid set-interval: "
 226                    << set_interval_element->Str();
 227       } else {
 228         SetInterval(interval * base::Time::kMillisecondsPerSecond);
 229       }
 230     }
 231
 232     bool did_set_sequence_id = false;
 233     const XmlElement* expected_sequence_id_element =
 234         result_element->FirstNamed(QName(kChromotingXmlNamespace,
 235                                          kExpectedSequenceIdTag));
 236     if (expected_sequence_id_element) {
 237       // The sequence ID sent in the previous heartbeat was not what the server
 238       // expected, so send another heartbeat with the expected sequence ID.
 239       const std::string& expected_sequence_id_str =
 240           expected_sequence_id_element->BodyText();
 241       int expected_sequence_id;
 242       if (!base::StringToInt(expected_sequence_id_str, &expected_sequence_id)) {
 243         LOG(ERROR) << "Received invalid " << kExpectedSequenceIdTag << ": " <<
 244             expected_sequence_id_element->Str();
 245       } else {
 246         SetSequenceId(expected_sequence_id);
 247         sequence_id_recent_set_num_++;
 248         did_set_sequence_id = true;
 249       }
 250     }
 251     if (!did_set_sequence_id) {
 252       // It seems the bot accepted our signature and our message.
 253       sequence_id_recent_set_num_ = 0;
 254
 255       // Notify listener of the first successful heartbeat.
 256       if (!heartbeat_succeeded_) {
 257         on_heartbeat_successful_callback_.Run();
 258       }
 259       heartbeat_succeeded_ = true;
 260
 261       // Notify caller of SetHostOfflineReason that we got an ack.
 262       if (is_offline_heartbeat_response) {
 263         OnHostOfflineReasonAck();
 264       }
 265     }
 266   }
 267 }
 268
 269 void HeartbeatSender::SetInterval(int interval) {
 270   if (interval != interval_ms_) {
 271     interval_ms_ = interval;
 272
 273     // Restart the timer with the new interval.
 274     if (timer_.IsRunning()) {
 275       timer_.Stop();
 276       timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(interval_ms_),
 277                    this, &HeartbeatSender::SendStanza);
 278     }
 279   }
 280 }
 281
 282 void HeartbeatSender::SetSequenceId(int sequence_id) {
 283   sequence_id_ = sequence_id;
 284   // Setting the sequence ID may be a symptom of a temporary server-side
 285   // problem, which would affect many hosts, so don't send a new heartbeat
 286   // immediately, as many hosts doing so may overload the server.
 287   // But the server will usually set the sequence ID when it receives the first
 288   // heartbeat from a host. In that case, we can send a new heartbeat
 289   // immediately, as that only happens once per host instance.
 290   if (!sequence_id_was_set_) {
 291     ResendStanza();
 292   } else {
 293     HOST_LOG << "The heartbeat sequence ID has been set more than once: "
 294               << "the new value is " << sequence_id;
 295     double delay = pow(2.0, sequence_id_recent_set_num_) *
 296         (1 + base::RandDouble()) * kResendDelayMs;
 297     if (delay <= interval_ms_) {
 298       timer_resend_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(delay),
 299                           this, &HeartbeatSender::ResendStanza);
 300     }
 301   }
 302   sequence_id_was_set_ = true;
 303 }
 304
 305 scoped_ptr<XmlElement> HeartbeatSender::CreateHeartbeatMessage() {
 306   // Create heartbeat stanza.
 307   scoped_ptr<XmlElement> heartbeat(new XmlElement(
 308       QName(kChromotingXmlNamespace, kHeartbeatQueryTag)));
 309   heartbeat->AddAttr(QName(kChromotingXmlNamespace, kHostIdAttr), host_id_);
 310   heartbeat->AddAttr(QName(kChromotingXmlNamespace, kSequenceIdAttr),
 311                  base::IntToString(sequence_id_));
 312   if (!host_offline_reason_.empty()) {
 313     heartbeat->AddAttr(
 314         QName(kChromotingXmlNamespace, kHostOfflineReasonAttr),
 315         host_offline_reason_);
 316   }
 317   heartbeat->AddElement(CreateSignature().release());
 318   // Append host version.
 319   scoped_ptr<XmlElement> version_tag(new XmlElement(
 320       QName(kChromotingXmlNamespace, kHostVersionTag)));
 321   version_tag->AddText(STRINGIZE(VERSION));
 322   heartbeat->AddElement(version_tag.release());
 323   // Append log message (which isn't signed).
 324   scoped_ptr<XmlElement> log(ServerLogEntry::MakeStanza());
 325   scoped_ptr<ServerLogEntry> log_entry(MakeLogEntryForHeartbeat());
 326   AddHostFieldsToLogEntry(log_entry.get());
 327   log->AddElement(log_entry->ToStanza().release());
 328   heartbeat->AddElement(log.release());
 329   return heartbeat.Pass();
 330 }
 331
 332 scoped_ptr<XmlElement> HeartbeatSender::CreateSignature() {
 333   scoped_ptr<XmlElement> signature_tag(new XmlElement(
 334       QName(kChromotingXmlNamespace, kHeartbeatSignatureTag)));
 335
 336   std::string message = signal_strategy_->GetLocalJid() + ' ' +
 337       base::IntToString(sequence_id_);
 338   std::string signature(host_key_pair_->SignMessage(message));
 339   signature_tag->AddText(signature);
 340
 341   return signature_tag.Pass();
 342 }
 343
 344 }  // namespace remoting