Collect stats to investigate the viability of UDP

chrome/browser/net/network_stats.h

Index: chrome/browser/net/network_stats.h
===================================================================
--- chrome/browser/net/network_stats.h	(revision 0)
+++ chrome/browser/net/network_stats.h	(revision 0)
@@ -0,0 +1,221 @@
+// Copyright (c) 2011 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.
+
+#ifndef CHROME_BROWSER_NET_NETWORK_STATS_H_
+#define CHROME_BROWSER_NET_NETWORK_STATS_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/scoped_ptr.h"
+#include "base/time.h"
+#include "chrome/browser/io_thread.h"
+#include "net/base/address_list.h"
+#include "net/base/completion_callback.h"
+#include "net/base/host_port_pair.h"
+#include "net/base/host_resolver.h"
+#include "net/base/io_buffer.h"
+#include "net/base/ip_endpoint.h"
+#include "net/base/test_data_stream.h"
+#include "net/socket/socket.h"
+
+namespace chrome_browser_net {
+
+// This class is used for live experiment of network connectivity (either TCP or
+// UDP) metrics. A small percentage of users participate in this experiment. All
+// users (who are in the experiment) must have enabled "UMA upload".
+//
+// This class collects the following stats from users who have opted in.
+// a) What percentage of users can get a message end-to-end to a UDP server?
+// b) What percentage of users can get a message end-to-end to a TCP server?
+// c) What is the latency for UDP and TCP.
+// d) If connectivity failed, at what stage (Connect or Write or Read) did it
+// fail?
+
+class NetworkStats {
+ public:
+  enum Status {              // Used in HISTOGRAM_ENUMERATION.
+    SUCCESS,                 // Successfully received bytes from the server.
+    IP_STRING_PARSE_FAILED,  // Parsing of IP string failed.
+    RESOLVE_FAILED,          // Host resolution failed.
+    CONNECT_FAILED,          // Connection to the server failed.
+    WRITE_FAILED,            // Sending an echo message to the server failed.
+    READ_FAILED,             // Reading the reply from the server failed.
+    READ_VERIFY_FAILED,      // Verification of data failed.
+    STATUS_MAX,              // Bounding value.
+  };
+
+ protected:
+  // Constructs an NetworkStats object that collects metrics for network
+  // connectivity (either TCP or UDP).
+  NetworkStats();
+  virtual ~NetworkStats();
+
+  // Initializes |finished_callback_| and the number of bytes to send to the
+  // server. |finished_callback| is called when we are done with the test.
+  // |finished_callback| is mainly useful for unittests.
+  void Initialize(int bytes_to_send,
+                  net::CompletionCallback* finished_callback);
+
+  // This method is called after socket connection is completed. It will send
+  // |bytes_to_send| bytes to |server| by calling SendData(). After successfully
+  // sending data to the |server|, it calls ReadData() to read/verify the data
+  // from the |server|. Returns true if successful.
+  bool DoStart(int result);
+
+  // Collects network connectivity stats. This is called when all the data from
+  // server is read or when there is a failure during connect/read/write.
+  virtual void Finish(Status status, int result) {}
+
+  // This method is called from Finish() and calls |finished_callback_| callback
+  // to indicate that the test has finished.
+  void DoFinishCallback(int result);
+
+  // Returns the number of bytes to be sent to the |server|.
+  int load_size() const { return load_size_; }
+
+  // Helper methods to get and set |socket_|.
+  net::Socket* socket() { return socket_.get(); }
+  void set_socket(net::Socket* socket);
+
+  // Returns |start_time_| (used by histograms).
+  base::TimeTicks start_time() const { return start_time_; }
+
+ private:
+  // Verifies the data and calls Finish() if there is an error or if all bytes
+  // are read. Returns true if Finish() is called otherwise returns false.
+  bool ReadComplete(int result);
+
+  // Callbacks when an internal IO is completed.
+  void OnReadComplete(int result);
+  void OnWriteComplete(int result);
+
+  // Reads data from server until an error occurs.
+  void ReadData();
+
+  // Sends data to server until an error occurs.
+  int SendData();
+
+  // The socket handle for this session.
+  scoped_ptr<net::Socket> socket_;
+
+  // The read buffer used to read data from the socket.
+  scoped_refptr<net::IOBuffer> read_buffer_;
+
+  // The write buffer used to write data to the socket.
+  scoped_refptr<net::DrainableIOBuffer> write_buffer_;
+
+  // Some counters for the session.
+  int load_size_;
+  int bytes_to_read_;
+  int bytes_to_send_;
+
+  // |stream_| is used to generate data to be sent to the server and it is also
+  // used to verify the data received from the server.
+  net::TestDataStream stream_;
+
+  // Callback to call when data is read from the server.
+  net::CompletionCallbackImpl<NetworkStats> read_callback_;
+
+  // Callback to call when data is sent to the server.
+  net::CompletionCallbackImpl<NetworkStats> write_callback_;
+
+  // Callback to call when echo protocol is successefully finished or whenever
+  // there is an error (this allows unittests to wait until echo protocol's
+  // round trip is finished).
+  net::CompletionCallback* finished_callback_;
+
+  // The time when the session was started.
+  base::TimeTicks start_time_;
+};
+
+class UDPStatsClient : public NetworkStats {
+ public:
+  // Constructs an UDPStatsClient object that collects metrics for UDP
+  // connectivity.
+  UDPStatsClient();
+  virtual ~UDPStatsClient();
+
+  // Starts the client, connecting to |server|.
+  // Client will send |bytes_to_send| bytes to |server|.
+  // When client has received all echoed bytes from the server, or
+  // when an error occurs causing the client to stop, |Finish| will be
+  // called with a net status code.
+  // |Finish| will collect histogram stats.
+  // Returns true if successful in starting the client.
+  bool Start(const std::string& ip_str,
+             int port,
+             int bytes_to_send,
+             net::CompletionCallback* callback);
+
+ protected:
+  // Allow tests to access our innards for testing purposes.
+  friend class NetworkStatsTestUDP;
+
+  // Collects stats for UDP connectivity. This is called when all the data from
+  // server is read or when there is a failure during connect/read/write.
+  virtual void Finish(Status status, int result);
+};
+
+class TCPStatsClient : public NetworkStats {
+ public:
+  // Constructs a TCPStatsClient object that collects metrics for TCP
+  // connectivity.
+  TCPStatsClient();
+  virtual ~TCPStatsClient();
+
+  // Starts the client, connecting to |server|.
+  // Client will send |bytes_to_send| bytes.
+  // When the client has received all echoed bytes from the server, or
+  // when an error occurs causing the client to stop, |Finish| will be
+  // called with a net status code.
+  // |Finish| will collect histogram stats.
+  // Returns true if successful in starting the client.
+  bool Start(net::HostResolver* host_resolver,
+             const net::HostPortPair& server,
+             int bytes_to_send,
+             net::CompletionCallback* callback);
+
+ protected:
+  // Allow tests to access our innards for testing purposes.
+  friend class NetworkStatsTestTCP;
+
+  // Collects stats for TCP connectivity. This is called when all the data from
+  // server is read or when there is a failure during connect/read/write.
+  virtual void Finish(Status status, int result);
+
+ private:
+  // Callback that is called when host resolution is completed.
+  void OnResolveComplete(int result);
+
+  // Called after host is resolved. Creates TCPClientSocket and connects to the
+  // server.
+  bool DoConnect(int result);
+
+  // Callback that is called when connect is completed and calls DoStart() to
+  // start the echo protocl.
+  void OnConnectComplete(int result);
+
+  // Callback to call when host resolution is completed.
+  net::CompletionCallbackImpl<TCPStatsClient> resolve_callback_;
+
+  // Callback to call when connect is completed.
+  net::CompletionCallbackImpl<TCPStatsClient> connect_callback_;
+
+  // HostResolver fills out the |addresses_| after host resolution is completed.
+  net::AddressList addresses_;
+};
+
+// This collects the network connectivity stats for UDP and TCP for small
+// percentage of users who are participating in the experiment. All users must
+// have enabled "UMA upload". This method gets called only if UMA upload to the
+// server has succeeded.
+void CollectNetworkStats(const std::string& network_stats_server_url,
+                         IOThread* io_thread);
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_NETWORK_STATS_H_