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