Host offline status reporting.

remoting/host/host_status_sender.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/host/host_status_sender.h"
+
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/stringize_macros.h"
+#include "remoting/base/constants.h"
+#include "remoting/host/server_log_entry.h"
+#include "remoting/jingle_glue/iq_sender.h"
+#include "remoting/jingle_glue/signal_strategy.h"
+#include "third_party/libjingle/source/talk/xmllite/xmlelement.h"
+#include "third_party/libjingle/source/talk/xmpp/constants.h"
+
+using buzz::QName;
+using buzz::XmlElement;
+
+namespace remoting {
+
+namespace {
+
+const char kHostStatusTag[] = "host-status";
+const char kHostIdAttr[] = "hostid";
+const char kExitCodeAttr[] = "exit-code";
+const char kHostVersionTag[] = "host-version";
+const char kSignatureTag[] = "signature";
+const char kStatusAttr[] = "status";
+const char kSignatureTimeAttr[] = "time";
+
+}  // namespace
+
+HostStatusSender::HostStatusSender(
+    const std::string& host_id,
+    SignalStrategy* signal_strategy,
+    scoped_refptr<RsaKeyPair> key_pair,
+    const std::string& directory_bot_jid)
+    : host_id_(host_id),
+      signal_strategy_(signal_strategy),
+      key_pair_(key_pair),
+      directory_bot_jid_(directory_bot_jid) {
+  DCHECK(signal_strategy_);
+  DCHECK(key_pair_.get());
+
+  signal_strategy_->AddListener(this);
+}
+
+HostStatusSender::~HostStatusSender() {
+  signal_strategy_->RemoveListener(this);
+}
+
+void HostStatusSender::OnSignalStrategyStateChange(
+    SignalStrategy::State state) {
+  if (state == SignalStrategy::CONNECTED)
+    iq_sender_.reset(new IqSender(signal_strategy_));
+  else if (state == SignalStrategy::DISCONNECTED)
+    iq_sender_.reset();
+}
+
+bool HostStatusSender::OnSignalStrategyIncomingStanza(
+    const XmlElement* stanza) {
+  return false;
+}
+
+void HostStatusSender::SendOfflineStatus(int exit_code) {
+  SendHostStatus(OFFLINE, exit_code);
+}
+
+void HostStatusSender::SendOnlineStatus() {
+  SendHostStatus(ONLINE, 0);
+}
+
+void HostStatusSender::SendHostStatus(HostStatus status, int exit_code) {
+  SignalStrategy::State state = signal_strategy_->GetState();
+  if (state == SignalStrategy::CONNECTED) {
+    LOG(INFO) << "Sending host status '"
+              << status
+              << "' to "
+              << directory_bot_jid_;
+
+    iq_sender_->SendIq(buzz::STR_SET,
+                       directory_bot_jid_,
+                       CreateHostStatusMessage(status, exit_code),
+                       IqSender::ReplyCallback());
+  } else {
+    LOG(INFO) << "Cannot send host status to '"
+              << directory_bot_jid_
+              << " ' because the state of the SignalStrategy is "
+              << state;
+  }
+}
+
+scoped_ptr<XmlElement> HostStatusSender::CreateHostStatusMessage(
+    HostStatus status, int exit_code) {
+  // Create host status stanza.
+  scoped_ptr<XmlElement> host_status(new XmlElement(
+      QName(kChromotingXmlNamespace, kHostStatusTag)));
+  host_status->AddAttr(
+      QName(kChromotingXmlNamespace, kHostIdAttr), host_id_);
+  host_status->AddAttr(
+      QName(kChromotingXmlNamespace, kStatusAttr), base::IntToString(status));

[rmsousa, 2013/07/04 01:20:14]

we typically don't send/receive enums as raw numbers, we send them as strings.
(i.e. 'rem:status="ONLINE"' rather than 'rem:status="0"')

(for other enums [that are only used for logs] we use lowercase, but we already
use all caps for the status string in the JSON (See
https://code.google.com/p/chromium/codesearch#chromium/src/remoting/webapp/ho...),
so we should be consistent with that)

[weitao, 2013/07/09 00:37:40]

Done.

+
+  if (status == OFFLINE) {
+    host_status->AddAttr(
+        QName(kChromotingXmlNamespace, kExitCodeAttr),

[rmsousa, 2013/07/04 01:20:14]

For this one, I'm inclined to say that we should also treat it as an enum (and
send a stringized version of the enum names, such as
"INVALID_HOST_CONFIGURATION", or "invalid-host-configuration"), rather than an
integer.

Exit codes do make sense as pure integers (saying that "a [Unix] program's exit
code is '103'" is an acceptable sentence, it's not like saying that "a host's
status is '1'"), but the codes that we'll actually see here are defined as
values of an enum
(https://code.google.com/p/chromium/codesearch#chromium/src/remoting/host/host...).
Treating them as enums and stringizing them requires some more work (including
server-side) to handle it, but it does make the attribute more semantic, and has
the advantage that if we later add a new exit code, an older webapp that doesn't
recognize that exit code can show it as, for example, "Unknown host exit code:
'INVALID_HOST_CONFIGURATION'" as opposed to "Unknown host exit code: '137'".

[weitao, 2013/07/09 00:37:40]

Done.

+        base::IntToString(exit_code));
+  }
+
+  host_status->AddElement(CreateSignature(status, exit_code).release());
+
+  // Append host version.
+  scoped_ptr<XmlElement> version_tag(new XmlElement(
+      QName(kChromotingXmlNamespace, kHostVersionTag)));
+  version_tag->AddText(STRINGIZE(VERSION));
+  host_status->AddElement(version_tag.release());
+
+  // Append log message (which isn't signed).
+  scoped_ptr<XmlElement> log(ServerLogEntry::MakeStanza());
+  scoped_ptr<ServerLogEntry> log_entry(ServerLogEntry::MakeForHostStatus());
+  log_entry->AddHostFields();
+  log->AddElement(log_entry->ToStanza().release());

[rmsousa, 2013/07/04 01:20:14]

this log message should include the status and exit code as well.

[weitao, 2013/07/09 00:37:40]

Done.

+  host_status->AddElement(log.release());
+  return host_status.Pass();
+}
+
+scoped_ptr<XmlElement> HostStatusSender::CreateSignature(
+    HostStatus status, int exit_code) {
+  scoped_ptr<XmlElement> signature_tag(new XmlElement(
+      QName(kChromotingXmlNamespace, kSignatureTag)));
+
+  // Number of seconds since epoch (Jan 1, 1970).
+  int64 time = static_cast<int64>(base::Time::Now().ToDoubleT());
+  std::string time_str(base::Int64ToString(time));
+
+  signature_tag->AddAttr(
+      QName(kChromotingXmlNamespace, kSignatureTimeAttr), time_str);
+
+  // Add a time stamp to the signature to prevent replay attacks.
+  std::string message =
+      signal_strategy_->GetLocalJid() +
+      " " +
+      time_str +
+      " " +
+      base::IntToString(status);
+
+  if (status == OFFLINE)
+    message += " " + base::IntToString(exit_code);
+
+  std::string signature(key_pair_->SignMessage(message));
+  signature_tag->AddText(signature);
+
+  return signature_tag.Pass();
+}
+
+}  // namespace remoting