Add status service for remoting host.

remoting/host/host_status_service.cc

Index: remoting/host/host_status_service.cc
diff --git a/remoting/host/host_status_service.cc b/remoting/host/host_status_service.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3141308f19587a484d7f9de2512bde4555e81a05
--- /dev/null
+++ b/remoting/host/host_status_service.cc
@@ -0,0 +1,224 @@
+// Copyright (c) 2012 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_service.h"
+
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
+#include "base/stl_util.h"
+#include "base/string_number_conversions.h"
+#include "base/string_util.h"
+#include "base/stringize_macros.h"
+#include "base/values.h"
+#include "net/base/ip_endpoint.h"
+#include "net/base/net_util.h"
+#include "remoting/host/websocket_connection.h"
+#include "remoting/host/websocket_listener.h"
+
+namespace remoting {
+
+namespace {
+
+// HostStatusService uses the first port available in the following range.
+const int kPortRangeMin = 12810;
+const int kPortRangeMax = 12820;
+
+const char kChromeExtensionUrlSchemePrefix[] = "chrome-extension://";
+
+#if defined(NDEBUG)
+const char* const kAllowedWebApplicationIds[] = {
+  "gbchcmhmhahfdphkhkmpfmihenigjmpp",  // Chrome Remote Desktop
+  "kgngmbheleoaphbjbaiobfdepmghbfah",  // Pre-release Chrome Remote Desktop
+  "odkaodonbgfohohmklejpjiejmcipmib",  // Dogfood Chrome Remote Desktop
+  "ojoimpklfciegopdfgeenehpalipignm",  // Chromoting canary
+};
+#endif
+
+// All messages we expect should be smaller than 64k.
+const uint64 kMaximumIncomingMessageSize = 65536;
+
+}  // namespace
+
+class HostStatusService::Connection : public WebSocketConnection::Delegate {
+ public:
+  // |service| owns Connection connection objects and must outlive them.
+  Connection(HostStatusService* service,
+             scoped_ptr<WebSocketConnection> websocket);
+  virtual ~Connection();
+
+  // WebSocketConnection::Delegate interface.
+  virtual void OnWebSocketMessage(const std::string& message) OVERRIDE;
+  virtual void OnWebSocketClosed() OVERRIDE;
+
+ private:
+  // Sends message with the specified |method| and |data|.
+  void SendMessage(const std::string& method,
+                   scoped_ptr<base::DictionaryValue> data);
+
+   // Closes the connection and destroys this object.
+  void Close();
+
+  HostStatusService* service_;
+  scoped_ptr<WebSocketConnection> websocket_;
+
+  DISALLOW_COPY_AND_ASSIGN(Connection);
+};
+
+HostStatusService::Connection::Connection(
+    HostStatusService* service,
+    scoped_ptr<WebSocketConnection> websocket)
+    : service_(service),
+      websocket_(websocket.Pass()) {
+  websocket_->Accept(this);
+  websocket_->set_maximum_message_size(kMaximumIncomingMessageSize);
+}
+
+HostStatusService::Connection::~Connection() {
+}
+
+void HostStatusService::Connection::OnWebSocketMessage(
+    const std::string& message) {
+  scoped_ptr<base::Value> json(
+      base::JSONReader::Read(message, base::JSON_ALLOW_TRAILING_COMMAS));
+
+  // Verify that we've received a valid JSON dictionary and extract |method| and
+  // |data| fields from it.
+  base::DictionaryValue* message_dict = NULL;
+  std::string method;
+  base::DictionaryValue* data = NULL;
+  if (!json.get() ||
+      !json->GetAsDictionary(&message_dict) ||
+      !message_dict->GetString("method", &method) ||
+      !message_dict->GetDictionary("data", &data)) {
+    LOG(ERROR) << "Received invalid message: " << message;
+    Close();
+    return;
+  }
+
+  if (method == "getHostStatus") {
+    SendMessage("hostStatus", service_->GetStatusMessage());
+  } else {
+    LOG(ERROR) << "Received message with unknown method: " << message;
+    scoped_ptr<base::DictionaryValue> response(new base::DictionaryValue());
+    response->SetString("method", method);
+    SendMessage("unsupportedMethod", response.Pass());
+    return;
+  }
+}
+
+void HostStatusService::Connection::OnWebSocketClosed() {
+  Close();
+}
+
+void HostStatusService::Connection::SendMessage(
+    const std::string& method,
+    scoped_ptr<base::DictionaryValue> data) {
+  scoped_ptr<base::DictionaryValue> message(new base::DictionaryValue());
+  message->SetString("method", method);
+  message->Set("data", data.release());
+
+  std::string message_json;
+  base::JSONWriter::Write(message.get(), &message_json);
+  websocket_->SendText(message_json);
+}
+
+void HostStatusService::Connection::Close() {
+  websocket_.reset();
+  service_->OnConnectionClosed(this);
+}
+
+HostStatusService::HostStatusService()
+    : started_(false) {
+  // TODO(sergeyu): Do we need to listen on IPv6 port too?
+  char ip[] = {127, 0, 0, 1};
+  net::IPAddressNumber localhost(ip, ip + sizeof(ip));
+  for (int port = kPortRangeMin; port < kPortRangeMax; ++port) {
+    net::IPEndPoint endpoint(localhost, port);
+    // base::Unretained is safe because we own |websocket_listener_|.
+    if (websocket_listener_.Listen(
+            endpoint,
+            base::Bind(&HostStatusService::OnNewConnection,
+                       base::Unretained(this)))) {
+      service_host_name_ = "localhost:" + base::UintToString(port);
+      LOG(INFO) << "Listening for WebSocket connections on localhost:" << port;
+      break;
+    }
+  }
+}
+
+HostStatusService::~HostStatusService() {
+  STLDeleteElements(&connections_);
+}
+
+void HostStatusService::SetHostIsUp(const std::string& host_id) {
+  started_ = true;
+  host_id_ = host_id;
+}
+void HostStatusService::SetHostIsDown() {
+  started_ = false;
+  host_id_.clear();
+}
+
+// static
+bool HostStatusService::IsAllowedOrigin(const std::string& origin) {
+#ifndef NDEBUG
+  // Allow all chrome extensions in Debug builds.
+  return StartsWithASCII(origin, kChromeExtensionUrlSchemePrefix, false);
+#else
+  // For Release builds allow only specific set of clients.
+  //
+  // TODO(sergeyu): Allow whitelisting of origins different from the ones in
+  // kAllowedWebApplicationIds (e.g. specify them in the host config).
+  std::string prefix(kChromeExtensionUrlSchemePrefix);
+  for (size_t i = 0; i < arraysize(kAllowedWebApplicationIds); ++i) {
+    if (origin == prefix + kAllowedWebApplicationIds[i]) {
+      return true;
+    }
+  }
+  return false;
+#endif
+}
+
+void HostStatusService::OnNewConnection(
+    scoped_ptr<WebSocketConnection> connection) {
+  if (connection->request_host() != service_host_name_) {
+    LOG(ERROR) << "Received connection for invalid host: "
+               << connection->request_host()
+               << ". Expected " << service_host_name_;
+    connection->Reject();
+    return;
+  }
+
+  if (connection->request_path() != "/remoting_host_status") {
+    LOG(ERROR) << "Received connection for unknown path: "
+               << connection->request_path();
+    connection->Reject();
+    return;
+  }
+
+  if (!IsAllowedOrigin(connection->origin())) {
+    LOG(ERROR) << "Rejecting connection from unknown origin: "
+               << connection->origin();
+    connection->Reject();
+    return;
+  }
+
+  // Accept connection.
+  connections_.insert(new Connection(this, connection.Pass()));
+}
+
+void HostStatusService::OnConnectionClosed(Connection* connection) {
+  connections_.erase(connection);
+  delete connection;
+}
+
+scoped_ptr<base::DictionaryValue> HostStatusService::GetStatusMessage() {
+  scoped_ptr<base::DictionaryValue> result(new base::DictionaryValue());
+  result->SetString("state", started_ ? "STARTED" : "STOPPED");
+  result->SetString("version", STRINGIZE(VERSION));
+  result->SetString("hostId", host_id_);
+  return result.Pass();
+}
+
+}  // namespace remoting