Notify NQE of TCP RTT values

net/socket/tcp_socket_posix.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 "net/socket/tcp_socket.h"
 
 #include <errno.h>
 #include <netinet/tcp.h>
 #include <sys/socket.h>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/posix/eintr_wrapper.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/task_runner_util.h"
 #include "base/threading/worker_pool.h"
+#include "base/time/default_tick_clock.h"
 #include "net/base/address_list.h"
 #include "net/base/connection_type_histograms.h"
 #include "net/base/io_buffer.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_errors.h"
 #include "net/base/network_activity_monitor.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/sockaddr_storage.h"
 #include "net/socket/socket_net_log_params.h"
 #include "net/socket/socket_posix.h"
@@ skipping 100 matching lines @@
 void CheckSupportAndMaybeEnableTCPFastOpen(bool user_enabled) {
 #if defined(OS_LINUX) || defined(OS_ANDROID)
   base::PostTaskAndReplyWithResult(
       base::WorkerPool::GetTaskRunner(/*task_is_slow=*/false).get(),
       FROM_HERE,
       base::Bind(SystemSupportsTCPFastOpen),
       base::Bind(RegisterTCPFastOpenIntentAndSupport, user_enabled));
 #endif
 }
 
-TCPSocketPosix::TCPSocketPosix(NetLog* net_log, const NetLog::Source& source)
-    : use_tcp_fastopen_(false),
+TCPSocketPosix::TCPSocketPosix(
+    scoped_ptr<SocketPerformanceWatcher> socket_performance_watcher,
+    NetLog* net_log,
+    const NetLog::Source& source)
+    : rtt_notifications_minimum_interval_(base::TimeDelta::FromSeconds(1)),
+      socket_performance_watcher_(std::move(socket_performance_watcher)),
+      tick_clock_(new base::DefaultTickClock()),
+      use_tcp_fastopen_(false),
       tcp_fastopen_write_attempted_(false),
       tcp_fastopen_connected_(false),
       tcp_fastopen_status_(TCP_FASTOPEN_STATUS_UNKNOWN),
       logging_multiple_connect_attempts_(false),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_SOCKET)) {
   net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
                       source.ToEventParametersCallback());
 }
 
 TCPSocketPosix::~TCPSocketPosix() {
@@ skipping 316 matching lines @@
 
 void TCPSocketPosix::EndLoggingMultipleConnectAttempts(int net_error) {
   if (logging_multiple_connect_attempts_) {
     LogConnectEnd(net_error);
     logging_multiple_connect_attempts_ = false;
   } else {
     NOTREACHED();
   }
 }
 
+void TCPSocketPosix::SetTickClockForTesting(
+    scoped_ptr<base::TickClock> tick_clock) {
+  tick_clock_.swap(tick_clock);

[Ryan Sleevi, 2016/04/11 22:06:56]

I believe this should be

tick_clock_.swap(std::move(tick_clock));

since tick_clock is named and thus may not be inferred as an rvalue reference.

[tbansal1, 2016/04/12 16:14:33]

This gave compilation error:
error: non-const lvalue reference to type 'unique_ptr<...>' cannot bind to a
temporary of type 'unique_ptr<...>'
Done. I updated it to how this is done elsewhere in //net
https://code.google.com/p/chromium/codesearch#chromium/src/net/sdch/sdch_owne...

+}
+
 void TCPSocketPosix::AcceptCompleted(scoped_ptr<TCPSocketPosix>* tcp_socket,
                                      IPEndPoint* address,
                                      const CompletionCallback& callback,
                                      int rv) {
   DCHECK_NE(ERR_IO_PENDING, rv);
   callback.Run(HandleAcceptCompleted(tcp_socket, address, rv));
 }
 
 int TCPSocketPosix::HandleAcceptCompleted(
     scoped_ptr<TCPSocketPosix>* tcp_socket,
@@ skipping 16 matching lines @@
                                         IPEndPoint* address) {
   DCHECK(accept_socket_);
 
   SockaddrStorage storage;
   if (accept_socket_->GetPeerAddress(&storage) != OK ||
       !address->FromSockAddr(storage.addr, storage.addr_len)) {
     accept_socket_.reset();
     return ERR_ADDRESS_INVALID;
   }
 
-  tcp_socket->reset(new TCPSocketPosix(net_log_.net_log(), net_log_.source()));
+  tcp_socket->reset(
+      new TCPSocketPosix(nullptr, net_log_.net_log(), net_log_.source()));
   (*tcp_socket)->socket_.reset(accept_socket_.release());
   return OK;
 }
 
 void TCPSocketPosix::ConnectCompleted(const CompletionCallback& callback,
-                                      int rv) const {
+                                      int rv) {
   DCHECK_NE(ERR_IO_PENDING, rv);
   callback.Run(HandleConnectCompleted(rv));
 }
 
-int TCPSocketPosix::HandleConnectCompleted(int rv) const {
+int TCPSocketPosix::HandleConnectCompleted(int rv) {
   // Log the end of this attempt (and any OS error it threw).
   if (rv != OK) {
     net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT,
                       NetLog::IntCallback("os_error", errno));
   } else {
     net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT);
+    NotifySocketPerformanceWatcher();
   }
 
   // Give a more specific error when the user is offline.
   if (rv == ERR_ADDRESS_UNREACHABLE && NetworkChangeNotifier::IsOffline())
     rv = ERR_INTERNET_DISCONNECTED;
 
   if (!logging_multiple_connect_attempts_)
     LogConnectEnd(rv);
 
   return rv;
@@ skipping 49 matching lines @@
     else
       g_tcp_fastopen_has_failed = true;
     UpdateTCPFastOpenStatusAfterRead();
   }
 
   if (rv < 0) {
     net_log_.AddEvent(NetLog::TYPE_SOCKET_READ_ERROR,
                       CreateNetLogSocketErrorCallback(rv, errno));
     return rv;
   }
+  NotifySocketPerformanceWatcher();
+
   net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED, rv,
                                 buf->data());
   NetworkActivityMonitor::GetInstance()->IncrementBytesReceived(rv);
 
   return rv;
 }
 
 void TCPSocketPosix::WriteCompleted(const scoped_refptr<IOBuffer>& buf,
                                     const CompletionCallback& callback,
                                     int rv) {
@@ skipping 11 matching lines @@
       // FastOpen is turned off on _any_ error. Implement optimizations,
       // such as turning off TCP FastOpen on more specific errors, and
       // re-attempting TCP FastOpen after a certain amount of time has passed.
       tcp_fastopen_status_ = TCP_FASTOPEN_ERROR;
       g_tcp_fastopen_has_failed = true;
     }
     net_log_.AddEvent(NetLog::TYPE_SOCKET_WRITE_ERROR,
                       CreateNetLogSocketErrorCallback(rv, errno));
     return rv;
   }
+  NotifySocketPerformanceWatcher();
+
   net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_SENT, rv,
                                 buf->data());
   NetworkActivityMonitor::GetInstance()->IncrementBytesSent(rv);
   return rv;
 }
 
 int TCPSocketPosix::TcpFastOpenWrite(IOBuffer* buf,
                                      int buf_len,
                                      const CompletionCallback& callback) {
   SockaddrStorage storage;
@@ skipping 47 matching lines @@
     // turning off TCP FastOpen on more specific errors.
     tcp_fastopen_status_ = TCP_FASTOPEN_ERROR;
     g_tcp_fastopen_has_failed = true;
     return rv;
   }
 
   tcp_fastopen_status_ = TCP_FASTOPEN_SLOW_CONNECT_RETURN;
   return socket_->WaitForWrite(buf, buf_len, callback);
 }
 
+void TCPSocketPosix::NotifySocketPerformanceWatcher() {
+#if defined(TCP_INFO)
+  // TODO(tbansal): Remove ScopedTracker once crbug.com/590254 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "590254 TCPSocketPosix::NotifySocketPerformanceWatcher"));
+
+  const base::TimeTicks now_ticks = tick_clock_->NowTicks();
+  // Do not notify |socket_performance_watcher_| if the last notification was
+  // recent than |rtt_notifications_minimum_interval_| ago. This helps in
+  // reducing the overall overhead of the tcp_info syscalls.
+  if (now_ticks - last_rtt_notification_ < rtt_notifications_minimum_interval_)
+    return;
+
+  // Check if |socket_performance_watcher_| is interested in receiving a RTT
+  // update notification.
+  if (!socket_performance_watcher_ ||
+      !socket_performance_watcher_->ShouldNotifyUpdatedRTT()) {
+    return;
+  }
+
+  tcp_info info;
+  if (!GetTcpInfo(socket_->socket_fd(), &info))
+    return;
+
+  // Only notify the |socket_performance_watcher_| if the RTT in |tcp_info|
+  // struct was populated. A value of 0 may be valid in certain cases
+  // (on very fast networks), but it is discarded. This means that
+  // some of the RTT values may be missed, but the values that are kept are
+  // guaranteed to be correct.
+  if (info.tcpi_rtt == 0 && info.tcpi_rttvar == 0)
+    return;
+
+  socket_performance_watcher_->OnUpdatedRTTAvailable(
+      base::TimeDelta::FromMicroseconds(info.tcpi_rtt));
+  last_rtt_notification_ = now_ticks;
+#endif  // defined(TCP_INFO)
+}
+
 void TCPSocketPosix::UpdateTCPFastOpenStatusAfterRead() {
   DCHECK(tcp_fastopen_status_ == TCP_FASTOPEN_FAST_CONNECT_RETURN ||
          tcp_fastopen_status_ == TCP_FASTOPEN_SLOW_CONNECT_RETURN);
 
   if (tcp_fastopen_write_attempted_ && !tcp_fastopen_connected_) {
     // TCP FastOpen connect-with-write was attempted, and failed.
     tcp_fastopen_status_ =
         (tcp_fastopen_status_ == TCP_FASTOPEN_FAST_CONNECT_RETURN ?
             TCP_FASTOPEN_FAST_CONNECT_READ_FAILED :
             TCP_FASTOPEN_SLOW_CONNECT_READ_FAILED);
@@ skipping 41 matching lines @@
     if (info.tcpi_rtt > 0) {
       *out_rtt = base::TimeDelta::FromMicroseconds(info.tcpi_rtt);
       return true;
     }
   }
 #endif  // defined(TCP_INFO)
   return false;
 }
 
 }  // namespace net