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/message_loop/message_loop_proxy.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/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/libjingle/source/talk/xmpp/constants.h"
  22 #include "third_party/webrtc/libjingle/xmllite/xmlelement.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
  37 const char kErrorTag[] = "error";
  38 const char kNotFoundTag[] = "item-not-found";
  39
  40 const char kHeartbeatResultTag[] = "heartbeat-result";
  41 const char kSetIntervalTag[] = "set-interval";
  42 const char kExpectedSequenceIdTag[] = "expected-sequence-id";
  43
  44 const int64 kDefaultHeartbeatIntervalMs = 5 * 60 * 1000;  // 5 minutes.
  45 const int64 kResendDelayMs = 10 * 1000;  // 10 seconds.
  46 const int64 kResendDelayOnHostNotFoundMs = 10 * 1000; // 10 seconds.
  47 const int kMaxResendOnHostNotFoundCount = 12;  // 2 minutes (12 x 10 seconds).
  48
  49 }  // namespace
  50
  51 HeartbeatSender::HeartbeatSender(
  52     Listener* listener,
  53     const std::string& host_id,
  54     SignalStrategy* signal_strategy,
  55     scoped_refptr<RsaKeyPair> key_pair,
  56     const std::string& directory_bot_jid)
  57     : listener_(listener),
  58       host_id_(host_id),
  59       signal_strategy_(signal_strategy),
  60       key_pair_(key_pair),
  61       directory_bot_jid_(directory_bot_jid),
  62       interval_ms_(kDefaultHeartbeatIntervalMs),
  63       sequence_id_(0),
  64       sequence_id_was_set_(false),
  65       sequence_id_recent_set_num_(0),
  66       heartbeat_succeeded_(false),
  67       failed_startup_heartbeat_count_(0) {
  68   DCHECK(signal_strategy_);
  69   DCHECK(key_pair_.get());
  70
  71   signal_strategy_->AddListener(this);
  72
  73   // Start heartbeats if the |signal_strategy_| is already connected.
  74   OnSignalStrategyStateChange(signal_strategy_->GetState());
  75 }
  76
  77 HeartbeatSender::~HeartbeatSender() {
  78   signal_strategy_->RemoveListener(this);
  79 }
  80
  81 void HeartbeatSender::OnSignalStrategyStateChange(SignalStrategy::State state) {
  82   if (state == SignalStrategy::CONNECTED) {
  83     iq_sender_.reset(new IqSender(signal_strategy_));
  84     SendStanza();
  85     timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(interval_ms_),
  86                  this, &HeartbeatSender::SendStanza);
  87   } else if (state == SignalStrategy::DISCONNECTED) {
  88     request_.reset();
  89     iq_sender_.reset();
  90     timer_.Stop();
  91     timer_resend_.Stop();
  92   }
  93 }
  94
  95 bool HeartbeatSender::OnSignalStrategyIncomingStanza(
  96     const buzz::XmlElement* stanza) {
  97   return false;
  98 }
  99
 100 void HeartbeatSender::SendStanza() {
 101   DoSendStanza();
 102   // Make sure we don't send another heartbeat before the heartbeat interval
 103   // has expired.
 104   timer_resend_.Stop();
 105 }
 106
 107 void HeartbeatSender::ResendStanza() {
 108   DoSendStanza();
 109   // Make sure we don't send another heartbeat before the heartbeat interval
 110   // has expired.
 111   timer_.Reset();
 112 }
 113
 114 void HeartbeatSender::DoSendStanza() {
 115   VLOG(1) << "Sending heartbeat stanza to " << directory_bot_jid_;
 116   request_ = iq_sender_->SendIq(
 117       buzz::STR_SET, directory_bot_jid_, CreateHeartbeatMessage(),
 118       base::Bind(&HeartbeatSender::ProcessResponse,
 119                  base::Unretained(this)));
 120   ++sequence_id_;
 121 }
 122
 123 void HeartbeatSender::ProcessResponse(IqRequest* request,
 124                                       const XmlElement* response) {
 125   std::string type = response->Attr(buzz::QN_TYPE);
 126   if (type == buzz::STR_ERROR) {
 127     const XmlElement* error_element =
 128         response->FirstNamed(QName(buzz::NS_CLIENT, kErrorTag));
 129     if (error_element) {
 130       if (error_element->FirstNamed(QName(buzz::NS_STANZA, kNotFoundTag))) {
 131         LOG(ERROR) << "Received error: Host ID not found";
 132         // If the host was registered immediately before it sends a heartbeat,
 133         // then server-side latency may prevent the server recognizing the
 134         // host ID in the heartbeat. So even if all of the first few heartbeats
 135         // get a "host ID not found" error, that's not a good enough reason to
 136         // exit.
 137         failed_startup_heartbeat_count_++;
 138         if (!heartbeat_succeeded_ && (failed_startup_heartbeat_count_ <=
 139                 kMaxResendOnHostNotFoundCount)) {
 140           timer_resend_.Start(FROM_HERE,
 141                               base::TimeDelta::FromMilliseconds(
 142                                   kResendDelayOnHostNotFoundMs),
 143                               this,
 144                               &HeartbeatSender::ResendStanza);
 145           return;
 146         }
 147         listener_->OnUnknownHostIdError();
 148         return;
 149       }
 150     }
 151
 152     LOG(ERROR) << "Received error in response to heartbeat: "
 153                << response->Str();
 154     return;
 155   }
 156
 157   // Notify listener of the first successful heartbeat.
 158   if (!heartbeat_succeeded_) {
 159     listener_->OnHeartbeatSuccessful();
 160   }
 161   heartbeat_succeeded_ = true;
 162
 163   // This method must only be called for error or result stanzas.
 164   DCHECK_EQ(std::string(buzz::STR_RESULT), type);
 165
 166   const XmlElement* result_element =
 167       response->FirstNamed(QName(kChromotingXmlNamespace, kHeartbeatResultTag));
 168   if (result_element) {
 169     const XmlElement* set_interval_element =
 170         result_element->FirstNamed(QName(kChromotingXmlNamespace,
 171                                          kSetIntervalTag));
 172     if (set_interval_element) {
 173       const std::string& interval_str = set_interval_element->BodyText();
 174       int interval;
 175       if (!base::StringToInt(interval_str, &interval) || interval <= 0) {
 176         LOG(ERROR) << "Received invalid set-interval: "
 177                    << set_interval_element->Str();
 178       } else {
 179         SetInterval(interval * base::Time::kMillisecondsPerSecond);
 180       }
 181     }
 182
 183     bool did_set_sequence_id = false;
 184     const XmlElement* expected_sequence_id_element =
 185         result_element->FirstNamed(QName(kChromotingXmlNamespace,
 186                                          kExpectedSequenceIdTag));
 187     if (expected_sequence_id_element) {
 188       // The sequence ID sent in the previous heartbeat was not what the server
 189       // expected, so send another heartbeat with the expected sequence ID.
 190       const std::string& expected_sequence_id_str =
 191           expected_sequence_id_element->BodyText();
 192       int expected_sequence_id;
 193       if (!base::StringToInt(expected_sequence_id_str, &expected_sequence_id)) {
 194         LOG(ERROR) << "Received invalid " << kExpectedSequenceIdTag << ": " <<
 195             expected_sequence_id_element->Str();
 196       } else {
 197         SetSequenceId(expected_sequence_id);
 198         sequence_id_recent_set_num_++;
 199         did_set_sequence_id = true;
 200       }
 201     }
 202     if (!did_set_sequence_id) {
 203       sequence_id_recent_set_num_ = 0;
 204     }
 205   }
 206 }
 207
 208 void HeartbeatSender::SetInterval(int interval) {
 209   if (interval != interval_ms_) {
 210     interval_ms_ = interval;
 211
 212     // Restart the timer with the new interval.
 213     if (timer_.IsRunning()) {
 214       timer_.Stop();
 215       timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(interval_ms_),
 216                    this, &HeartbeatSender::SendStanza);
 217     }
 218   }
 219 }
 220
 221 void HeartbeatSender::SetSequenceId(int sequence_id) {
 222   sequence_id_ = sequence_id;
 223   // Setting the sequence ID may be a symptom of a temporary server-side
 224   // problem, which would affect many hosts, so don't send a new heartbeat
 225   // immediately, as many hosts doing so may overload the server.
 226   // But the server will usually set the sequence ID when it receives the first
 227   // heartbeat from a host. In that case, we can send a new heartbeat
 228   // immediately, as that only happens once per host instance.
 229   if (!sequence_id_was_set_) {
 230     ResendStanza();
 231   } else {
 232     HOST_LOG << "The heartbeat sequence ID has been set more than once: "
 233               << "the new value is " << sequence_id;
 234     double delay = pow(2.0, sequence_id_recent_set_num_) *
 235         (1 + base::RandDouble()) * kResendDelayMs;
 236     if (delay <= interval_ms_) {
 237       timer_resend_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(delay),
 238                           this, &HeartbeatSender::ResendStanza);
 239     }
 240   }
 241   sequence_id_was_set_ = true;
 242 }
 243
 244 scoped_ptr<XmlElement> HeartbeatSender::CreateHeartbeatMessage() {
 245   // Create heartbeat stanza.
 246   scoped_ptr<XmlElement> heartbeat(new XmlElement(
 247       QName(kChromotingXmlNamespace, kHeartbeatQueryTag)));
 248   heartbeat->AddAttr(QName(kChromotingXmlNamespace, kHostIdAttr), host_id_);
 249   heartbeat->AddAttr(QName(kChromotingXmlNamespace, kSequenceIdAttr),
 250                  base::IntToString(sequence_id_));
 251   heartbeat->AddElement(CreateSignature().release());
 252   // Append host version.
 253   scoped_ptr<XmlElement> version_tag(new XmlElement(
 254       QName(kChromotingXmlNamespace, kHostVersionTag)));
 255   version_tag->AddText(STRINGIZE(VERSION));
 256   heartbeat->AddElement(version_tag.release());
 257   // Append log message (which isn't signed).
 258   scoped_ptr<XmlElement> log(ServerLogEntry::MakeStanza());
 259   scoped_ptr<ServerLogEntry> log_entry(MakeLogEntryForHeartbeat());
 260   AddHostFieldsToLogEntry(log_entry.get());
 261   log->AddElement(log_entry->ToStanza().release());
 262   heartbeat->AddElement(log.release());
 263   return heartbeat.Pass();
 264 }
 265
 266 scoped_ptr<XmlElement> HeartbeatSender::CreateSignature() {
 267   scoped_ptr<XmlElement> signature_tag(new XmlElement(
 268       QName(kChromotingXmlNamespace, kHeartbeatSignatureTag)));
 269
 270   std::string message = signal_strategy_->GetLocalJid() + ' ' +
 271       base::IntToString(sequence_id_);
 272   std::string signature(key_pair_->SignMessage(message));
 273   signature_tag->AddText(signature);
 274
 275   return signature_tag.Pass();
 276 }
 277
 278 }  // namespace remoting