net/socket/tcp_socket_libevent.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/socket/tcp_socket.h"
   6
   7 #include <errno.h>
   8 #include <netinet/tcp.h>
   9 #include <sys/socket.h>
  10
  11 #include "base/bind.h"
  12 #include "base/logging.h"
  13 #include "base/metrics/histogram.h"
  14 #include "base/metrics/stats_counters.h"
  15 #include "base/posix/eintr_wrapper.h"
  16 #include "net/base/address_list.h"
  17 #include "net/base/connection_type_histograms.h"
  18 #include "net/base/io_buffer.h"
  19 #include "net/base/ip_endpoint.h"
  20 #include "net/base/net_errors.h"
  21 #include "net/base/net_util.h"
  22 #include "net/base/network_change_notifier.h"
  23 #include "net/socket/socket_libevent.h"
  24 #include "net/socket/socket_net_log_params.h"
  25
  26 // If we don't have a definition for TCPI_OPT_SYN_DATA, create one.
  27 #ifndef TCPI_OPT_SYN_DATA
  28 #define TCPI_OPT_SYN_DATA 32
  29 #endif
  30
  31 namespace net {
  32
  33 namespace {
  34
  35 // SetTCPNoDelay turns on/off buffering in the kernel. By default, TCP sockets
  36 // will wait up to 200ms for more data to complete a packet before transmitting.
  37 // After calling this function, the kernel will not wait. See TCP_NODELAY in
  38 // `man 7 tcp`.
  39 bool SetTCPNoDelay(int fd, bool no_delay) {
  40   int on = no_delay ? 1 : 0;
  41   int error = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
  42   return error == 0;
  43 }
  44
  45 // SetTCPKeepAlive sets SO_KEEPALIVE.
  46 bool SetTCPKeepAlive(int fd, bool enable, int delay) {
  47   int on = enable ? 1 : 0;
  48   if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on))) {
  49     PLOG(ERROR) << "Failed to set SO_KEEPALIVE on fd: " << fd;
  50     return false;
  51   }
  52
  53   // If we disabled TCP keep alive, our work is done here.
  54   if (!enable)
  55     return true;
  56
  57 #if defined(OS_LINUX) || defined(OS_ANDROID)
  58   // Set seconds until first TCP keep alive.
  59   if (setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, &delay, sizeof(delay))) {
  60     PLOG(ERROR) << "Failed to set TCP_KEEPIDLE on fd: " << fd;
  61     return false;
  62   }
  63   // Set seconds between TCP keep alives.
  64   if (setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, &delay, sizeof(delay))) {
  65     PLOG(ERROR) << "Failed to set TCP_KEEPINTVL on fd: " << fd;
  66     return false;
  67   }
  68 #endif
  69   return true;
  70 }
  71
  72 }  // namespace
  73
  74 //-----------------------------------------------------------------------------
  75
  76 TCPSocketLibevent::TCPSocketLibevent(NetLog* net_log,
  77                                      const NetLog::Source& source)
  78     : use_tcp_fastopen_(IsTCPFastOpenEnabled()),
  79       tcp_fastopen_connected_(false),
  80       fast_open_status_(FAST_OPEN_STATUS_UNKNOWN),
  81       logging_multiple_connect_attempts_(false),
  82       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_SOCKET)) {
  83   net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
  84                       source.ToEventParametersCallback());
  85 }
  86
  87 TCPSocketLibevent::~TCPSocketLibevent() {
  88   net_log_.EndEvent(NetLog::TYPE_SOCKET_ALIVE);
  89   if (tcp_fastopen_connected_) {
  90     UMA_HISTOGRAM_ENUMERATION("Net.TcpFastOpenSocketConnection",
  91                               fast_open_status_, FAST_OPEN_MAX_VALUE);
  92   }
  93 }
  94
  95 int TCPSocketLibevent::Open(AddressFamily family) {
  96   DCHECK(!socket_);
  97   socket_.reset(new SocketLibevent);
  98   int rv = socket_->Open(ConvertAddressFamily(family));
  99   if (rv != OK)
 100     socket_.reset();
 101   return rv;
 102 }
 103
 104 int TCPSocketLibevent::AdoptConnectedSocket(int socket_fd,
 105                                             const IPEndPoint& peer_address) {
 106   DCHECK(!socket_);
 107
 108   SockaddrStorage storage;
 109   if (!peer_address.ToSockAddr(storage.addr, &storage.addr_len) &&
 110       // For backward compatibility, allows the empty address.
 111       !(peer_address == IPEndPoint())) {
 112     return ERR_ADDRESS_INVALID;
 113   }
 114
 115   socket_.reset(new SocketLibevent);
 116   int rv = socket_->AdoptConnectedSocket(socket_fd, storage);
 117   if (rv != OK)
 118     socket_.reset();
 119   return rv;
 120 }
 121
 122 int TCPSocketLibevent::Bind(const IPEndPoint& address) {
 123   DCHECK(socket_);
 124
 125   SockaddrStorage storage;
 126   if (!address.ToSockAddr(storage.addr, &storage.addr_len))
 127     return ERR_ADDRESS_INVALID;
 128
 129   return socket_->Bind(storage);
 130 }
 131
 132 int TCPSocketLibevent::Listen(int backlog) {
 133   DCHECK(socket_);
 134   return socket_->Listen(backlog);
 135 }
 136
 137 int TCPSocketLibevent::Accept(scoped_ptr<TCPSocketLibevent>* tcp_socket,
 138                               IPEndPoint* address,
 139                               const CompletionCallback& callback) {
 140   DCHECK(tcp_socket);
 141   DCHECK(!callback.is_null());
 142   DCHECK(socket_);
 143   DCHECK(!accept_socket_);
 144
 145   net_log_.BeginEvent(NetLog::TYPE_TCP_ACCEPT);
 146
 147   int rv = socket_->Accept(
 148       &accept_socket_,
 149       base::Bind(&TCPSocketLibevent::AcceptCompleted,
 150                  base::Unretained(this), tcp_socket, address, callback));
 151   if (rv != ERR_IO_PENDING)
 152     rv = HandleAcceptCompleted(tcp_socket, address, rv);
 153   return rv;
 154 }
 155
 156 int TCPSocketLibevent::Connect(const IPEndPoint& address,
 157                                const CompletionCallback& callback) {
 158   DCHECK(socket_);
 159
 160   if (!logging_multiple_connect_attempts_)
 161     LogConnectBegin(AddressList(address));
 162
 163   net_log_.BeginEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT,
 164                       CreateNetLogIPEndPointCallback(&address));
 165
 166   SockaddrStorage storage;
 167   if (!address.ToSockAddr(storage.addr, &storage.addr_len))
 168     return ERR_ADDRESS_INVALID;
 169
 170   if (use_tcp_fastopen_) {
 171     // With TCP FastOpen, we pretend that the socket is connected.
 172     DCHECK(!tcp_fastopen_connected_);
 173     socket_->SetPeerAddress(storage);
 174     return OK;
 175   }
 176
 177   int rv = socket_->Connect(storage,
 178                             base::Bind(&TCPSocketLibevent::ConnectCompleted,
 179                                        base::Unretained(this), callback));
 180   if (rv != ERR_IO_PENDING)
 181     rv = HandleConnectCompleted(rv);
 182   return rv;
 183 }
 184
 185 bool TCPSocketLibevent::IsConnected() const {
 186   if (!socket_)
 187     return false;
 188
 189   if (use_tcp_fastopen_ && !tcp_fastopen_connected_ &&
 190       socket_->HasPeerAddress()) {
 191     // With TCP FastOpen, we pretend that the socket is connected.
 192     // This allows GetPeerAddress() to return peer_address_.
 193     return true;
 194   }
 195
 196   return socket_->IsConnected();
 197 }
 198
 199 bool TCPSocketLibevent::IsConnectedAndIdle() const {
 200   // TODO(wtc): should we also handle the TCP FastOpen case here,
 201   // as we do in IsConnected()?
 202   return socket_ && socket_->IsConnectedAndIdle();
 203 }
 204
 205 int TCPSocketLibevent::Read(IOBuffer* buf,
 206                             int buf_len,
 207                             const CompletionCallback& callback) {
 208   DCHECK(socket_);
 209   DCHECK(!callback.is_null());
 210
 211   int rv = socket_->Read(
 212       buf, buf_len,
 213       base::Bind(&TCPSocketLibevent::ReadCompleted,
 214                  base::Unretained(this), base::Unretained(buf), callback));
 215   if (rv >= 0)
 216     RecordFastOpenStatus();
 217   if (rv != ERR_IO_PENDING)
 218     rv = HandleReadCompleted(buf, rv);
 219   return rv;
 220 }
 221
 222 int TCPSocketLibevent::Write(IOBuffer* buf,
 223                              int buf_len,
 224                              const CompletionCallback& callback) {
 225   DCHECK(socket_);
 226   DCHECK(!callback.is_null());
 227
 228   CompletionCallback write_callback =
 229       base::Bind(&TCPSocketLibevent::WriteCompleted,
 230                  base::Unretained(this), base::Unretained(buf), callback);
 231   int rv;
 232   if (use_tcp_fastopen_ && !tcp_fastopen_connected_) {
 233     rv = TcpFastOpenWrite(buf, buf_len, write_callback);
 234   } else {
 235     rv = socket_->Write(buf, buf_len, write_callback);
 236   }
 237
 238   if (rv != ERR_IO_PENDING)
 239     rv = HandleWriteCompleted(buf, rv);
 240   return rv;
 241 }
 242
 243 int TCPSocketLibevent::GetLocalAddress(IPEndPoint* address) const {
 244   DCHECK(address);
 245
 246   if (!socket_)
 247     return ERR_SOCKET_NOT_CONNECTED;
 248
 249   SockaddrStorage storage;
 250   int rv = socket_->GetLocalAddress(&storage);
 251   if (rv != OK)
 252     return rv;
 253
 254   if (!address->FromSockAddr(storage.addr, storage.addr_len))
 255     return ERR_ADDRESS_INVALID;
 256
 257   return OK;
 258 }
 259
 260 int TCPSocketLibevent::GetPeerAddress(IPEndPoint* address) const {
 261   DCHECK(address);
 262
 263   if (!IsConnected())
 264     return ERR_SOCKET_NOT_CONNECTED;
 265
 266   SockaddrStorage storage;
 267   int rv = socket_->GetPeerAddress(&storage);
 268   if (rv != OK)
 269     return rv;
 270
 271   if (!address->FromSockAddr(storage.addr, storage.addr_len))
 272     return ERR_ADDRESS_INVALID;
 273
 274   return OK;
 275 }
 276
 277 int TCPSocketLibevent::SetDefaultOptionsForServer() {
 278   DCHECK(socket_);
 279   return SetAddressReuse(true);
 280 }
 281
 282 void TCPSocketLibevent::SetDefaultOptionsForClient() {
 283   DCHECK(socket_);
 284
 285   // This mirrors the behaviour on Windows. See the comment in
 286   // tcp_socket_win.cc after searching for "NODELAY".
 287   // If SetTCPNoDelay fails, we don't care.
 288   SetTCPNoDelay(socket_->socket_fd(), true);
 289
 290   // TCP keep alive wakes up the radio, which is expensive on mobile. Do not
 291   // enable it there. It's useful to prevent TCP middleboxes from timing out
 292   // connection mappings. Packets for timed out connection mappings at
 293   // middleboxes will either lead to:
 294   // a) Middleboxes sending TCP RSTs. It's up to higher layers to check for this
 295   // and retry. The HTTP network transaction code does this.
 296   // b) Middleboxes just drop the unrecognized TCP packet. This leads to the TCP
 297   // stack retransmitting packets per TCP stack retransmission timeouts, which
 298   // are very high (on the order of seconds). Given the number of
 299   // retransmissions required before killing the connection, this can lead to
 300   // tens of seconds or even minutes of delay, depending on OS.
 301 #if !defined(OS_ANDROID) && !defined(OS_IOS)
 302   const int kTCPKeepAliveSeconds = 45;
 303
 304   SetTCPKeepAlive(socket_->socket_fd(), true, kTCPKeepAliveSeconds);
 305 #endif
 306 }
 307
 308 int TCPSocketLibevent::SetAddressReuse(bool allow) {
 309   DCHECK(socket_);
 310
 311   // SO_REUSEADDR is useful for server sockets to bind to a recently unbound
 312   // port. When a socket is closed, the end point changes its state to TIME_WAIT
 313   // and wait for 2 MSL (maximum segment lifetime) to ensure the remote peer
 314   // acknowledges its closure. For server sockets, it is usually safe to
 315   // bind to a TIME_WAIT end point immediately, which is a widely adopted
 316   // behavior.
 317   //
 318   // Note that on *nix, SO_REUSEADDR does not enable the TCP socket to bind to
 319   // an end point that is already bound by another socket. To do that one must
 320   // set SO_REUSEPORT instead. This option is not provided on Linux prior
 321   // to 3.9.
 322   //
 323   // SO_REUSEPORT is provided in MacOS X and iOS.
 324   int boolean_value = allow ? 1 : 0;
 325   int rv = setsockopt(socket_->socket_fd(), SOL_SOCKET, SO_REUSEADDR,
 326                       &boolean_value, sizeof(boolean_value));
 327   if (rv < 0)
 328     return MapSystemError(errno);
 329   return OK;
 330 }
 331
 332 int TCPSocketLibevent::SetReceiveBufferSize(int32 size) {
 333   DCHECK(socket_);
 334   int rv = setsockopt(socket_->socket_fd(), SOL_SOCKET, SO_RCVBUF,
 335                       reinterpret_cast<const char*>(&size), sizeof(size));
 336   return (rv == 0) ? OK : MapSystemError(errno);
 337 }
 338
 339 int TCPSocketLibevent::SetSendBufferSize(int32 size) {
 340   DCHECK(socket_);
 341   int rv = setsockopt(socket_->socket_fd(), SOL_SOCKET, SO_SNDBUF,
 342                       reinterpret_cast<const char*>(&size), sizeof(size));
 343   return (rv == 0) ? OK : MapSystemError(errno);
 344 }
 345
 346 bool TCPSocketLibevent::SetKeepAlive(bool enable, int delay) {
 347   DCHECK(socket_);
 348   return SetTCPKeepAlive(socket_->socket_fd(), enable, delay);
 349 }
 350
 351 bool TCPSocketLibevent::SetNoDelay(bool no_delay) {
 352   DCHECK(socket_);
 353   return SetTCPNoDelay(socket_->socket_fd(), no_delay);
 354 }
 355
 356 void TCPSocketLibevent::Close() {
 357   socket_.reset();
 358   tcp_fastopen_connected_ = false;
 359   fast_open_status_ = FAST_OPEN_STATUS_UNKNOWN;
 360 }
 361
 362 bool TCPSocketLibevent::UsingTCPFastOpen() const {
 363   return use_tcp_fastopen_;
 364 }
 365
 366 bool TCPSocketLibevent::IsValid() const {
 367   return socket_ != NULL && socket_->socket_fd() != kInvalidSocket;
 368 }
 369
 370 void TCPSocketLibevent::StartLoggingMultipleConnectAttempts(
 371     const AddressList& addresses) {
 372   if (!logging_multiple_connect_attempts_) {
 373     logging_multiple_connect_attempts_ = true;
 374     LogConnectBegin(addresses);
 375   } else {
 376     NOTREACHED();
 377   }
 378 }
 379
 380 void TCPSocketLibevent::EndLoggingMultipleConnectAttempts(int net_error) {
 381   if (logging_multiple_connect_attempts_) {
 382     LogConnectEnd(net_error);
 383     logging_multiple_connect_attempts_ = false;
 384   } else {
 385     NOTREACHED();
 386   }
 387 }
 388
 389 void TCPSocketLibevent::AcceptCompleted(
 390     scoped_ptr<TCPSocketLibevent>* tcp_socket,
 391     IPEndPoint* address,
 392     const CompletionCallback& callback,
 393     int rv) {
 394   DCHECK_NE(ERR_IO_PENDING, rv);
 395   callback.Run(HandleAcceptCompleted(tcp_socket, address, rv));
 396 }
 397
 398 int TCPSocketLibevent::HandleAcceptCompleted(
 399     scoped_ptr<TCPSocketLibevent>* tcp_socket,
 400     IPEndPoint* address,
 401     int rv) {
 402   if (rv == OK)
 403     rv = BuildTcpSocketLibevent(tcp_socket, address);
 404
 405   if (rv == OK) {
 406     net_log_.EndEvent(NetLog::TYPE_TCP_ACCEPT,
 407                       CreateNetLogIPEndPointCallback(address));
 408   } else {
 409     net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_ACCEPT, rv);
 410   }
 411
 412   return rv;
 413 }
 414
 415 int TCPSocketLibevent::BuildTcpSocketLibevent(
 416     scoped_ptr<TCPSocketLibevent>* tcp_socket,
 417     IPEndPoint* address) {
 418   DCHECK(accept_socket_);
 419
 420   SockaddrStorage storage;
 421   if (accept_socket_->GetPeerAddress(&storage) != OK ||
 422       !address->FromSockAddr(storage.addr, storage.addr_len)) {
 423     accept_socket_.reset();
 424     return ERR_ADDRESS_INVALID;
 425   }
 426
 427   tcp_socket->reset(new TCPSocketLibevent(net_log_.net_log(),
 428                                           net_log_.source()));
 429   (*tcp_socket)->socket_.reset(accept_socket_.release());
 430   return OK;
 431 }
 432
 433 void TCPSocketLibevent::ConnectCompleted(const CompletionCallback& callback,
 434                                          int rv) const {
 435   DCHECK_NE(ERR_IO_PENDING, rv);
 436   callback.Run(HandleConnectCompleted(rv));
 437 }
 438
 439 int TCPSocketLibevent::HandleConnectCompleted(int rv) const {
 440   // Log the end of this attempt (and any OS error it threw).
 441   if (rv != OK) {
 442     net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT,
 443                       NetLog::IntegerCallback("os_error", errno));
 444   } else {
 445     net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT);
 446   }
 447
 448   // Give a more specific error when the user is offline.
 449   if (rv == ERR_ADDRESS_UNREACHABLE && NetworkChangeNotifier::IsOffline())
 450     rv = ERR_INTERNET_DISCONNECTED;
 451
 452   if (!logging_multiple_connect_attempts_)
 453     LogConnectEnd(rv);
 454
 455   return rv;
 456 }
 457
 458 void TCPSocketLibevent::LogConnectBegin(const AddressList& addresses) const {
 459   base::StatsCounter connects("tcp.connect");
 460   connects.Increment();
 461
 462   net_log_.BeginEvent(NetLog::TYPE_TCP_CONNECT,
 463                       addresses.CreateNetLogCallback());
 464 }
 465
 466 void TCPSocketLibevent::LogConnectEnd(int net_error) const {
 467   if (net_error != OK) {
 468     net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_CONNECT, net_error);
 469     return;
 470   }
 471
 472   UpdateConnectionTypeHistograms(CONNECTION_ANY);
 473
 474   SockaddrStorage storage;
 475   int rv = socket_->GetLocalAddress(&storage);
 476   if (rv != OK) {
 477     PLOG(ERROR) << "GetLocalAddress() [rv: " << rv << "] error: ";
 478     NOTREACHED();
 479     net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_CONNECT, rv);
 480     return;
 481   }
 482
 483   net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT,
 484                     CreateNetLogSourceAddressCallback(storage.addr,
 485                                                       storage.addr_len));
 486 }
 487
 488 void TCPSocketLibevent::ReadCompleted(IOBuffer* buf,
 489                                       const CompletionCallback& callback,
 490                                       int rv) {
 491   DCHECK_NE(ERR_IO_PENDING, rv);
 492   // Records fast open status regardless of error in asynchronous case.
 493   // TODO(rdsmith,jri): Change histogram name to indicate it could be called on
 494   // error.
 495   RecordFastOpenStatus();
 496   callback.Run(HandleReadCompleted(buf, rv));
 497 }
 498
 499 int TCPSocketLibevent::HandleReadCompleted(IOBuffer* buf, int rv) {
 500   if (rv < 0) {
 501     net_log_.AddEvent(NetLog::TYPE_SOCKET_READ_ERROR,
 502                       CreateNetLogSocketErrorCallback(rv, errno));
 503     return rv;
 504   }
 505
 506   base::StatsCounter read_bytes("tcp.read_bytes");
 507   read_bytes.Add(rv);
 508   net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED, rv,
 509                                 buf->data());
 510   return rv;
 511 }
 512
 513 void TCPSocketLibevent::WriteCompleted(IOBuffer* buf,
 514                                        const CompletionCallback& callback,
 515                                        int rv) const {
 516   DCHECK_NE(ERR_IO_PENDING, rv);
 517   callback.Run(HandleWriteCompleted(buf, rv));
 518 }
 519
 520 int TCPSocketLibevent::HandleWriteCompleted(IOBuffer* buf, int rv) const {
 521   if (rv < 0) {
 522     net_log_.AddEvent(NetLog::TYPE_SOCKET_WRITE_ERROR,
 523                       CreateNetLogSocketErrorCallback(rv, errno));
 524     return rv;
 525   }
 526
 527   base::StatsCounter write_bytes("tcp.write_bytes");
 528   write_bytes.Add(rv);
 529   net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_SENT, rv,
 530                                 buf->data());
 531   return rv;
 532 }
 533
 534 int TCPSocketLibevent::TcpFastOpenWrite(
 535     IOBuffer* buf,
 536     int buf_len,
 537     const CompletionCallback& callback) {
 538   SockaddrStorage storage;
 539   int rv = socket_->GetPeerAddress(&storage);
 540   if (rv != OK)
 541     return rv;
 542
 543   int flags = 0x20000000;  // Magic flag to enable TCP_FASTOPEN.
 544 #if defined(OS_LINUX)
 545   // sendto() will fail with EPIPE when the system doesn't support TCP Fast
 546   // Open. Theoretically that shouldn't happen since the caller should check
 547   // for system support on startup, but users may dynamically disable TCP Fast
 548   // Open via sysctl.
 549   flags |= MSG_NOSIGNAL;
 550 #endif // defined(OS_LINUX)
 551   rv = HANDLE_EINTR(sendto(socket_->socket_fd(),
 552                            buf->data(),
 553                            buf_len,
 554                            flags,
 555                            storage.addr,
 556                            storage.addr_len));
 557   tcp_fastopen_connected_ = true;
 558
 559   if (rv >= 0) {
 560     fast_open_status_ = FAST_OPEN_FAST_CONNECT_RETURN;
 561     return rv;
 562   }
 563
 564   DCHECK_NE(EPIPE, errno);
 565
 566   // If errno == EINPROGRESS, that means the kernel didn't have a cookie
 567   // and would block. The kernel is internally doing a connect() though.
 568   // Remap EINPROGRESS to EAGAIN so we treat this the same as our other
 569   // asynchronous cases. Note that the user buffer has not been copied to
 570   // kernel space.
 571   if (errno == EINPROGRESS) {
 572     rv = ERR_IO_PENDING;
 573   } else {
 574     rv = MapSystemError(errno);
 575   }
 576
 577   if (rv != ERR_IO_PENDING) {
 578     fast_open_status_ = FAST_OPEN_ERROR;
 579     return rv;
 580   }
 581
 582   fast_open_status_ = FAST_OPEN_SLOW_CONNECT_RETURN;
 583   return socket_->WaitForWrite(buf, buf_len, callback);
 584 }
 585
 586 void TCPSocketLibevent::RecordFastOpenStatus() {
 587   if (use_tcp_fastopen_ &&
 588       (fast_open_status_ == FAST_OPEN_FAST_CONNECT_RETURN ||
 589        fast_open_status_ == FAST_OPEN_SLOW_CONNECT_RETURN)) {
 590     DCHECK_NE(FAST_OPEN_STATUS_UNKNOWN, fast_open_status_);
 591     bool getsockopt_success(false);
 592     bool server_acked_data(false);
 593 #if defined(TCP_INFO)
 594     // Probe to see the if the socket used TCP Fast Open.
 595     tcp_info info;
 596     socklen_t info_len = sizeof(tcp_info);
 597     getsockopt_success =
 598         getsockopt(socket_->socket_fd(), IPPROTO_TCP, TCP_INFO,
 599                    &info, &info_len) == 0 &&
 600         info_len == sizeof(tcp_info);
 601     server_acked_data = getsockopt_success &&
 602         (info.tcpi_options & TCPI_OPT_SYN_DATA);
 603 #endif
 604     if (getsockopt_success) {
 605       if (fast_open_status_ == FAST_OPEN_FAST_CONNECT_RETURN) {
 606         fast_open_status_ = (server_acked_data ? FAST_OPEN_SYN_DATA_ACK :
 607                              FAST_OPEN_SYN_DATA_NACK);
 608       } else {
 609         fast_open_status_ = (server_acked_data ? FAST_OPEN_NO_SYN_DATA_ACK :
 610                              FAST_OPEN_NO_SYN_DATA_NACK);
 611       }
 612     } else {
 613       fast_open_status_ = (fast_open_status_ == FAST_OPEN_FAST_CONNECT_RETURN ?
 614                            FAST_OPEN_SYN_DATA_FAILED :
 615                            FAST_OPEN_NO_SYN_DATA_FAILED);
 616     }
 617   }
 618 }
 619
 620 }  // namespace net