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