remoting/host/heartbeat_sender.h

   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 #ifndef REMOTING_HOST_HEARTBEAT_SENDER_H_
   6 #define REMOTING_HOST_HEARTBEAT_SENDER_H_
   7
   8 #include <string>
   9
  10 #include "base/callback.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/gtest_prod_util.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "base/threading/thread_checker.h"
  16 #include "base/timer/timer.h"
  17 #include "remoting/base/rsa_key_pair.h"
  18 #include "remoting/signaling/signal_strategy.h"
  19
  20 namespace base {
  21 class TimeDelta;
  22 }  // namespace base
  23
  24 namespace buzz {
  25 class XmlElement;
  26 }  // namespace buzz
  27
  28 namespace remoting {
  29
  30 class RsaKeyPair;
  31 class IqRequest;
  32 class IqSender;
  33
  34 // HeartbeatSender periodically sends heartbeat stanzas to the Chromoting Bot.
  35 // Each heartbeat stanza looks as follows:
  36 //
  37 // <iq type="set" to="remoting@bot.talk.google.com"
  38 //     from="user@gmail.com/chromoting123123" id="5" xmlns="jabber:client">
  39 //   <rem:heartbeat rem:hostid="a1ddb11e-8aef-11df-bccf-18a905b9cb5a"
  40 //                  rem:sequence-id="456"
  41 //                  xmlns:rem="google:remoting">
  42 //     <rem:signature>.signature.</rem:signature>
  43 //   </rem:heartbeat>
  44 // </iq>
  45 //
  46 // Normally the heartbeat indicates that the host is healthy and ready to
  47 // accept new connections from a client, but the rem:heartbeat xml element can
  48 // optionally include a rem:host-offline-reason attribute, which indicates that
  49 // the host cannot accept connections from the client (and might possibly be
  50 // shutting down).  The value of the host-offline-reason attribute can be either
  51 // a string from host_exit_codes.cc (i.e. "INVALID_HOST_CONFIGURATION" string)
  52 // or one of kHostOfflineReasonXxx constants (i.e. "POLICY_READ_ERROR" string).
  53 //
  54 // The sequence-id attribute of the heartbeat is a zero-based incrementally
  55 // increasing integer unique to each heartbeat from a single host.
  56 // The Bot checks the value, and if it is incorrect, includes the
  57 // correct value in the result stanza. The host should then send another
  58 // heartbeat, with the correct sequence-id, and increment the sequence-id in
  59 // susbequent heartbeats.
  60 // The signature is a base-64 encoded SHA-1 hash, signed with the host's
  61 // private RSA key. The message being signed is the full Jid concatenated with
  62 // the sequence-id, separated by one space. For example, for the heartbeat
  63 // stanza above, the message that is signed is
  64 // "user@gmail.com/chromoting123123 456".
  65 //
  66 // The Bot sends the following result stanza in response to each successful
  67 // heartbeat:
  68 //
  69 //  <iq type="set" from="remoting@bot.talk.google.com"
  70 //      to="user@gmail.com/chromoting123123" id="5" xmlns="jabber:client">
  71 //    <rem:heartbeat-result xmlns:rem="google:remoting">
  72 //      <rem:set-interval>300</rem:set-interval>
  73 //    </rem:heartbeat-result>
  74 //  </iq>
  75 //
  76 // The set-interval tag is used to specify desired heartbeat interval
  77 // in seconds. The heartbeat-result and the set-interval tags are
  78 // optional. Host uses default heartbeat interval if it doesn't find
  79 // set-interval tag in the result Iq stanza it receives from the
  80 // server.
  81 // If the heartbeat's sequence-id was incorrect, the Bot sends a result
  82 // stanza of this form:
  83 //
  84 //  <iq type="set" from="remoting@bot.talk.google.com"
  85 //      to="user@gmail.com/chromoting123123" id="5" xmlns="jabber:client">
  86 //    <rem:heartbeat-result xmlns:rem="google:remoting">
  87 //      <rem:expected-sequence-id>654</rem:expected-sequence-id>
  88 //    </rem:heartbeat-result>
  89 //  </iq>
  90 class HeartbeatSender : public SignalStrategy::Listener {
  91  public:
  92   // |signal_strategy| and |delegate| must outlive this
  93   // object. Heartbeats will start when the supplied SignalStrategy
  94   // enters the CONNECTED state.
  95   //
  96   // |on_heartbeat_successful_callback| is invoked after the first successful
  97   // heartbeat.
  98   //
  99   // |on_unknown_host_id_error| is invoked when the host ID is permanently not
 100   // recognized by the server.
 101   HeartbeatSender(const base::Closure& on_heartbeat_successful_callback,
 102                   const base::Closure& on_unknown_host_id_error,
 103                   const std::string& host_id,
 104                   SignalStrategy* signal_strategy,
 105                   const scoped_refptr<const RsaKeyPair>& host_key_pair,
 106                   const std::string& directory_bot_jid);
 107   ~HeartbeatSender() override;
 108
 109   // Sets host offline reason for future heartbeat stanzas, and initiates
 110   // sending a stanza right away.
 111   //
 112   // For discussion of allowed values for |host_offline_reason| argument,
 113   // please see the description of rem:host-offline-reason xml attribute in
 114   // the class-level comments above.
 115   //
 116   // |ack_callback| will be called once, when the bot acks receiving the
 117   // |host_offline_reason| or when |timeout| is reached.
 118   void SetHostOfflineReason(
 119       const std::string& host_offline_reason,
 120       const base::TimeDelta& timeout,
 121       const base::Callback<void(bool success)>& ack_callback);
 122
 123   // SignalStrategy::Listener interface.
 124   void OnSignalStrategyStateChange(SignalStrategy::State state) override;
 125   bool OnSignalStrategyIncomingStanza(const buzz::XmlElement* stanza) override;
 126
 127  private:
 128   FRIEND_TEST_ALL_PREFIXES(HeartbeatSenderTest,
 129                            DoSendStanzaWithExpectedSequenceId);
 130   FRIEND_TEST_ALL_PREFIXES(HeartbeatSenderTest, ProcessResponseSetInterval);
 131   FRIEND_TEST_ALL_PREFIXES(HeartbeatSenderTest,
 132                            ProcessResponseExpectedSequenceId);
 133   friend class HeartbeatSenderTest;
 134
 135   void SendStanza();
 136   void ResendStanza();
 137   void DoSendStanza();
 138   void ProcessResponse(bool is_offline_heartbeat_response,
 139                        IqRequest* request,
 140                        const buzz::XmlElement* response);
 141   void SetInterval(int interval);
 142   void SetSequenceId(int sequence_id);
 143
 144   // Handlers for host-offline-reason completion and timeout.
 145   void OnHostOfflineReasonTimeout();
 146   void OnHostOfflineReasonAck();
 147
 148   // Helper methods used by DoSendStanza() to generate heartbeat stanzas.
 149   scoped_ptr<buzz::XmlElement> CreateHeartbeatMessage();
 150   scoped_ptr<buzz::XmlElement> CreateSignature();
 151
 152   base::Closure on_heartbeat_successful_callback_;
 153   base::Closure on_unknown_host_id_error_;
 154   std::string host_id_;
 155   SignalStrategy* signal_strategy_;
 156   scoped_refptr<const RsaKeyPair> host_key_pair_;
 157   std::string directory_bot_jid_;
 158   scoped_ptr<IqSender> iq_sender_;
 159   scoped_ptr<IqRequest> request_;
 160   int interval_ms_;
 161   base::RepeatingTimer<HeartbeatSender> timer_;
 162   base::OneShotTimer<HeartbeatSender> timer_resend_;
 163   int sequence_id_;
 164   bool sequence_id_was_set_;
 165   int sequence_id_recent_set_num_;
 166   bool heartbeat_succeeded_;
 167   int failed_startup_heartbeat_count_;
 168
 169   // Fields to send and indicate completion of sending host-offline-reason.
 170   std::string host_offline_reason_;
 171   base::Callback<void(bool success)> host_offline_reason_ack_callback_;
 172   base::OneShotTimer<HeartbeatSender> host_offline_reason_timeout_timer_;
 173
 174   base::ThreadChecker thread_checker_;
 175
 176   DISALLOW_COPY_AND_ASSIGN(HeartbeatSender);
 177 };
 178
 179 }  // namespace remoting
 180
 181 #endif  // REMOTING_HOST_HEARTBEAT_SENDER_H_