blob: ff17df573a1943672567906c24d26f8325042c14 [file] [log] [blame]
// Copyright 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 <bitset>
#include <string>
#include <vector>
#include "base/memory/scoped_ptr.h"
#include "base/metrics/histogram.h"
#include "base/time/time.h"
#include "chrome/browser/io_thread.h"
#include "chrome/browser/net/probe_message.h"
#include "net/base/address_list.h"
#include "net/base/completion_callback.h"
#include "net/base/host_port_pair.h"
#include "net/base/io_buffer.h"
#include "net/proxy/proxy_info.h"
namespace net {
class ClientSocketFactory;
class DatagramClientSocket;
class HostResolver;
class SingleRequestHostResolver;
namespace chrome_browser_net {
// This class is used for live experiment of network connectivity (for UDP)
// metrics. A small percentage of users participate in this experiment. All
// users (who are in the experiment) must have enabled "UMA upload".
// In the experiments, clients request the server to send some probing packets,
// collect some stats, and send back the results via UMA reports.
// This class collects the following stats from users who have opted in.
// a) RTT.
// b) packet inter-arrival time.
// c) packet losses for correlation and FEC experiments.
// d) packet losses for NAT binding test after idling for a certain period.
// There are three tests in one experiment. Right before each test, a
// HelloRequest is sent to get an updated token.
// 1. |START_PACKET_TEST|: 21 packets are sent from the server to the client
// without pacing.
// 2. |PACED_PACKET_TEST| or |NON_PACED_PACKET_TEST|: After the first test,
// 21 packets are sent from the server to the client with or without pacing.
// If pacing, the pacing rate is computed from the first test.
// 3. |NAT_BIND_TEST|: 2 packets are sent from the server to the client with
// a randomly generated delay of 1~300 seconds.
// At the end of these tests, we send another HelloRequest to test whether
// the network is still connected and has not changed (e.g. from Wifi to 3g).
class NetworkStats {
enum Status { // Used in HISTOGRAM_ENUMERATION.
SUCCESS, // Successfully received bytes from the server.
SOCKET_CREATE_FAILED, // Socket creation failed.
RESOLVE_FAILED, // Host resolution failed.
CONNECT_FAILED, // Connection to the server failed.
WRITE_FAILED, // Sending a message to the server failed.
READ_TIMED_OUT, // Reading the reply from the server timed out.
READ_FAILED, // Reading the reply from the server failed.
STATUS_MAX, // Bounding value.
enum ReadState { // Used to track if |socket_| has a pending read.
enum WriteState { // Used to track if |socket_| has a pending write.
// |TestType| specifies the possible tests we may run
// (except for the first and the last serving as boundaries).
enum TestType {
// The first one is for requesting token, not a probe test. Put it here
// because we use it as a symbol for sending the HelloRequest packet to
// acquire the token.
START_PACKET_TEST, // First packet loss test (no pacing).
NON_PACED_PACKET_TEST, // Packet loss test with no pacing.
PACED_PACKET_TEST, // Packet loss test with pacing.
// Test whether NAT binding expires after some idle period.
// Pointer |socket_factory| is NOT deleted by this class.
explicit NetworkStats(net::ClientSocketFactory* socket_factory);
// NetworkStats is deleted in TestPhaseComplete() when all tests are done.
// Start the client and connect to |server|.
// A client will request a token and then perform several tests.
// When the client finishes all tests, or when an error occurs causing the
// client to stop, |TestPhaseComplete| will be called with a net status code.
// |TestPhaseComplete| will collect histogram stats.
// Return true if successful in starting the client.
bool Start(net::HostResolver* host_resolver,
const net::HostPortPair& server,
uint16 histogram_port,
bool has_proxy_server,
uint32 probe_bytes,
uint32 bytes_for_packet_size_test,
const net::CompletionCallback& callback);
friend class NetworkStatsTest;
// Start the test specified by the current_test_index_. It also resets all
// the book keeping data, before starting the new test.
void StartOneTest();
// Reset all the counters and the collected stats.
void ResetData();
// Callback that is called when host resolution is completed.
void OnResolveComplete(int result);
// Called after host is resolved. Creates UDPClientSocket and connects to the
// server. If successfully connected, then calls ConnectComplete() to start
// the network connectivity tests. Returns |false| if there is any error.
bool DoConnect(int result);
// This method is called after socket connection is completed. It will start
// the process of sending packets to |server| by calling SendHelloPacket().
// Return false if connection is not established (result is less than 0).
bool ConnectComplete(int result);
// Send a HelloRequest packet which asks for a token from the server. If
// a token is received, it will will add |START_PACKET_TEST| to the test
// queue.
void SendHelloRequest();
// Send a ProbeRequest packet which requests the server to send a set
// of Probing packets.
void SendProbeRequest();
// Read and process the data. Called from OnReadComplete() or ReadData().
// This function calls TestPhaseComplete() if there is a significant network
// error or if all packets in the current test are received.
// Return true if TestPhaseComplete() is called otherwise return false.
bool ReadComplete(int result);
// Callbacks when an internal IO (Read or Write) is completed.
void OnReadComplete(int result);
void OnWriteComplete(int result);
// Read data from server until an error or IO blocking occurs or reading is
// complete. Return the result value from socket reading and 0 if |socket_|
// is Null.
int ReadData();
// Send data contained in |str| to server.
// Return a negative value if IO blocking occurs or there is an error.
// Otherwise return net::OK.
int SendData(const std::string& str);
// Update the send buffer (telling it that |bytes_sent| has been sent).
// And reset |write_buffer_|.
void UpdateSendBuffer(int bytes_sent);
// Start a timer (with value |milliseconds|) for responses from the probe
// servers. |test_index| is the index of the test at vector |test_sequence_|
// and it is used as a parameter of the timer callback.
void StartReadDataTimer(uint32 milliseconds, uint32 test_index);
// Called when the StartReadDataTimer fires. |test_index| specifies
// the index of the test. If |current_test_index_| has changed to a
// different value, it indicates |test_index| has completed, then
// this method is a no-op.
void OnReadDataTimeout(uint32 test_index);
// Collect network connectivity stats. This is called when all the data from
// server is read or when there is a failure during connect/read/write. It
// will either start the next phase of the test, or it will self destruct
// at the end of this method. Returns true if a new test wasn't started and it
// was self destructed.
bool TestPhaseComplete(Status status, int result);
// This method is called from TestPhaseComplete() and calls
// |finished_callback_| callback to indicate that the test has finished.
void DoFinishCallback(int result);
// Update counters/metrics for the given |probe_packet|.
// Return true if all packets for the current test are received and
// false otherwise.
bool UpdateReception(const ProbePacket& probe_packet);
// Record all histograms for current test phase, which is assumed to be
// complete (i.e., we are no longer waiting for packets in this phase).
// |test_type| is the current test_type to be recorded. |status| is the
// status of the current test.
void RecordHistograms(TestType test_type);
// Collect the following network connectivity stats when
// kMaximumSequentialPackets (21) packets are sent from the server.
// a) Client received at least one packet.
// b) Client received the nth packet.
// c) The number of packets received for each subsequence of packets 1...n.
void RecordPacketsReceivedHistograms(TestType test_type);
// Collect the following network connectivity stats for the first
// kMaximumCorrelationPackets (6) packets in a test.
// Success/failure of each packet, to estimate reachability for users,
// and to estimate if there is a probabalistic dependency in packet loss when
// kMaximumCorrelationPackets packets are sent consecutively.
void RecordPacketLossSeriesHistograms(TestType test_type);
// Collect the average inter-arrival time (scaled up by 20 times because the
// minimum time value in a histogram is 1ms) of a sequence of probing packets.
void RecordInterArrivalHistograms(TestType test_type);
// Collect the RTT for the packet specified by the |index| in the current
// test.
void RecordRTTHistograms(TestType test_type, uint32 index);
// Collect whether the second packet in the NAT test is received for the
// given idle time.
void RecordNATTestReceivedHistograms(Status status);
// Collect whether we have the requested packet size was received or not in
// the PACKET_SIZE_TEST test.
void RecordPacketSizeTestReceivedHistograms(Status status);
// Record the time duration between sending the probe request and receiving
// the last probe packet excluding the pacing time requested by the client.
// This applies to both NAT bind test and paced/non-paced packet test.
void RecordSendToLastRecvDelayHistograms(TestType test_type);
// Return the next test type (internally increment |current_test_index_|)
// in |test_sequence_|;
TestType GetNextTest();
// These static variables are defined so that they can be changed in testing.
// Maximum number of tests in one activation of the experiment.
static uint32 maximum_tests_;
// Maximum number of packets for START/PACED/NON_PACED tests.
static uint32 maximum_sequential_packets_;
// Maximum number of packets for NAT binding test.
static uint32 maximum_NAT_packets_;
// Maximum time duration between the two packets for NAT Bind testing.
static uint32 maximum_NAT_idle_seconds_;
// Whether to start the probe test immediately after connect success.
// Used for unittest.
static bool start_test_after_connect_;
// The socket handler for this session.
scoped_ptr<net::DatagramClientSocket> socket_;
net::ClientSocketFactory* socket_factory_;
// 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_;
// Specify the port for which we are testing the network connectivity.
uint16 histogram_port_;
// Specify if there is a proxy server or not.
bool has_proxy_server_;
// HostResolver used to find the IP addresses.
scoped_ptr<net::SingleRequestHostResolver> resolver_;
// Addresses filled out by HostResolver after host resolution is completed.
net::AddressList addresses_;
// Callback to call when test is successefully finished or whenever
// there is an error (this will be used by unittests to check the result).
net::CompletionCallback finished_callback_;
// RTTs for each packet.
std::vector<base::TimeDelta> packet_rtt_;
// Time when sending probe_request, used for computing RTT.
base::TimeTicks probe_request_time_;
// Size of the probe packets requested to be sent from servers. We don't use
// |probe_packet_bytes_| during PACKET_SIZE_TEST.
uint32 probe_packet_bytes_;
// Size of the packet requested to be sent from servers for PACKET_SIZE_TEST.
uint32 bytes_for_packet_size_test_;
// bitmask indicating which packets are received.
std::bitset<21> packets_received_mask_;
// Arrival time of the first packet in the current test.
base::TimeTicks first_arrival_time_;
// Arrival time of the most recently received packet in the current test.
base::TimeTicks last_arrival_time_;
// Average time between two consecutive packets. It is updated when either all
// packets are received or timeout happens in the current test.
base::TimeDelta inter_arrival_time_;
// Target time duration for sending two consecutive packets at the server.
// It should be 0 for StartPacket test or NonPacedPacket test. For
// PacedPacket test, it is derived from the inter_arrival_time_ in the
// previous (StartPacket) test. For NATBind test, it is randomly generated
// between 1 second and |maximum_NAT_idle_seconds_| seconds.
base::TimeDelta pacing_interval_;
// A list of tests that will be performed in sequence.
std::vector<TestType> test_sequence_;
uint32 current_test_index_; // Index of the current test.
ProbeMessage probe_message_;
// Token received from server for authentication.
ProbePacket_Token token_;
// The state variables to track pending reads/writes.
ReadState read_state_;
WriteState write_state_;
// We use this factory to create timeout tasks for socket's ReadData.
base::WeakPtrFactory<NetworkStats> weak_factory_;
class ProxyDetector {
// Used for the callback that is called from |OnResolveProxyComplete|.
typedef base::Callback<void(bool)> OnResolvedCallback;
// Construct a ProxyDetector object that finds out if access to
// |server_address| goes through a proxy server or not. Calls the |callback|
// after proxy resolution is completed by currying the proxy resolution
// status.
ProxyDetector(net::ProxyService* proxy_service,
const net::HostPortPair& server_address,
OnResolvedCallback callback);
// This method uses |proxy_service_| to resolve the proxy for
// |server_address_|.
void StartResolveProxy();
// This object is deleted from |OnResolveProxyComplete|.
// Call the |callback_| by currying the proxy resolution status.
void OnResolveProxyComplete(int result);
// |proxy_service_| specifies the proxy service that is to be used to find
// if access to |server_address_| goes through proxy server or not.
net::ProxyService* proxy_service_;
// |server_address_| specifies the server host and port pair for which we are
// trying to see if access to it, goes through proxy or not.
net::HostPortPair server_address_;
// |callback_| will be called after proxy resolution is completed.
OnResolvedCallback callback_;
// |proxy_info_| holds proxy information returned by ResolveProxy.
net::ProxyInfo proxy_info_;
// Indicate if there is a pending a proxy resolution. We use this to assert
// that there is no in-progress proxy resolution request.
bool has_pending_proxy_resolution_;
// This collects the network connectivity stats for UDP protocol for small
// percentage of users who are participating in the experiment (by enabling
// "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);
// This starts a series of tests randomly selected among one of the three
// choices of probe packet sizes: 100 Bytes, 500 Bytes, 1200 Bytes.
void StartNetworkStatsTest(net::HostResolver* host_resolver,
const net::HostPortPair& server_address,
uint16 histogram_port,
bool has_proxy_server);
} // namespace chrome_browser_net