text: // 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 "net/socket/tcp_socket_win.h"
  
  #include <errno.h>
  #include <mstcpip.h>
  
  #include <utility>
  
  #include "base/callback_helpers.h"
  #include "base/files/file_util.h"
  #include "base/logging.h"
  #include "base/macros.h"
  #include "base/profiler/scoped_tracker.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/base/winsock_init.h"
  #include "net/base/winsock_util.h"
  #include "net/socket/socket_descriptor.h"
  #include "net/socket/socket_net_log_params.h"
  
  namespace net {
  
  namespace {
  
  const int kTCPKeepAliveSeconds = 45;
  
  int SetSocketReceiveBufferSize(SOCKET socket, int32_t size) {
    int rv = setsockopt(socket, SOL_SOCKET, SO_RCVBUF,
                        reinterpret_cast<const char*>(&size), sizeof(size));
    int net_error = (rv == 0) ? OK : MapSystemError(WSAGetLastError());
    DCHECK(!rv) << "Could not set socket receive buffer size: " << net_error;
    return net_error;
  }
  
  int SetSocketSendBufferSize(SOCKET socket, int32_t size) {
    int rv = setsockopt(socket, SOL_SOCKET, SO_SNDBUF,
                        reinterpret_cast<const char*>(&size), sizeof(size));
    int net_error = (rv == 0) ? OK : MapSystemError(WSAGetLastError());
    DCHECK(!rv) << "Could not set socket send buffer size: " << net_error;
    return net_error;
  }
  
  // Disable Nagle.
  // Enable TCP Keep-Alive to prevent NAT routers from timing out TCP
  // connections. See http://crbug.com/27400 for details.
  bool SetTCPKeepAlive(SOCKET socket, BOOL enable, int delay_secs) {
    unsigned delay = delay_secs * 1000;
    struct tcp_keepalive keepalive_vals = {
        enable ? 1u : 0u,  // TCP keep-alive on.
        delay,  // Delay seconds before sending first TCP keep-alive packet.
        delay,  // Delay seconds between sending TCP keep-alive packets.
    };
    DWORD bytes_returned = 0xABAB;
    int rv = WSAIoctl(socket, SIO_KEEPALIVE_VALS, &keepalive_vals,
                      sizeof(keepalive_vals), NULL, 0,
                      &bytes_returned, NULL, NULL);
    DCHECK(!rv) << "Could not enable TCP Keep-Alive for socket: " << socket
                << " [error: " << WSAGetLastError() << "].";
  
    // Disregard any failure in disabling nagle or enabling TCP Keep-Alive.
    return rv == 0;
  }
  
  int MapConnectError(int os_error) {
    switch (os_error) {
      // connect fails with WSAEACCES when Windows Firewall blocks the
      // connection.
      case WSAEACCES:
        return ERR_NETWORK_ACCESS_DENIED;
      case WSAETIMEDOUT:
        return ERR_CONNECTION_TIMED_OUT;
      default: {
        int net_error = MapSystemError(os_error);
        if (net_error == ERR_FAILED)
          return ERR_CONNECTION_FAILED;  // More specific than ERR_FAILED.
  
        // Give a more specific error when the user is offline.
        if (net_error == ERR_ADDRESS_UNREACHABLE &&
            NetworkChangeNotifier::IsOffline()) {
          return ERR_INTERNET_DISCONNECTED;
        }
  
        return net_error;
      }
    }
  }
  
  }  // namespace
  
  //-----------------------------------------------------------------------------
  
  // Nothing to do for Windows since it doesn't support TCP FastOpen.
  // TODO(jri): Remove these along with the corresponding global variables.
  bool IsTCPFastOpenSupported() { return false; }
  bool IsTCPFastOpenUserEnabled() { return false; }
  void CheckSupportAndMaybeEnableTCPFastOpen(bool user_enabled) {}
  
  // This class encapsulates all the state that has to be preserved as long as
  // there is a network IO operation in progress. If the owner TCPSocketWin is
  // destroyed while an operation is in progress, the Core is detached and it
  // lives until the operation completes and the OS doesn't reference any resource
  // declared on this class anymore.
  class TCPSocketWin::Core : public base::RefCounted<Core> {
   public:
    explicit Core(TCPSocketWin* socket);
  
    // Start watching for the end of a read or write operation.
    void WatchForRead();
    void WatchForWrite();
  
    // The TCPSocketWin is going away.
    void Detach() { socket_ = NULL; }
  
    // The separate OVERLAPPED variables for asynchronous operation.
    // |read_overlapped_| is used for both Connect() and Read().
    // |write_overlapped_| is only used for Write();
    OVERLAPPED read_overlapped_;
    OVERLAPPED write_overlapped_;
  
    // The buffers used in Read() and Write().
    scoped_refptr<IOBuffer> read_iobuffer_;
    scoped_refptr<IOBuffer> write_iobuffer_;
    int read_buffer_length_;
    int write_buffer_length_;
  
    bool non_blocking_reads_initialized_;
  
   private:
    friend class base::RefCounted<Core>;
  
    class ReadDelegate : public base::win::ObjectWatcher::Delegate {
     public:
      explicit ReadDelegate(Core* core) : core_(core) {}
      ~ReadDelegate() override {}
  
      // base::ObjectWatcher::Delegate methods:
      void OnObjectSignaled(HANDLE object) override;
  
     private:
      Core* const core_;
    };
  
    class WriteDelegate : public base::win::ObjectWatcher::Delegate {
     public:
      explicit WriteDelegate(Core* core) : core_(core) {}
      ~WriteDelegate() override {}
  
      // base::ObjectWatcher::Delegate methods:
      void OnObjectSignaled(HANDLE object) override;
  
     private:
      Core* const core_;
    };
  
    ~Core();
  
    // The socket that created this object.
    TCPSocketWin* socket_;
  
    // |reader_| handles the signals from |read_watcher_|.
    ReadDelegate reader_;
    // |writer_| handles the signals from |write_watcher_|.
    WriteDelegate writer_;
  
    // |read_watcher_| watches for events from Connect() and Read().
    base::win::ObjectWatcher read_watcher_;
    // |write_watcher_| watches for events from Write();
    base::win::ObjectWatcher write_watcher_;
  
    DISALLOW_COPY_AND_ASSIGN(Core);
  };
  
  TCPSocketWin::Core::Core(TCPSocketWin* socket)
      : read_buffer_length_(0),
        write_buffer_length_(0),
        non_blocking_reads_initialized_(false),
        socket_(socket),
        reader_(this),
        writer_(this) {
    memset(&read_overlapped_, 0, sizeof(read_overlapped_));
    memset(&write_overlapped_, 0, sizeof(write_overlapped_));
  
    read_overlapped_.hEvent = WSACreateEvent();
    write_overlapped_.hEvent = WSACreateEvent();
  }
  
  TCPSocketWin::Core::~Core() {
    // Make sure the message loop is not watching this object anymore.
    read_watcher_.StopWatching();
    write_watcher_.StopWatching();
  
    WSACloseEvent(read_overlapped_.hEvent);
    memset(&read_overlapped_, 0xaf, sizeof(read_overlapped_));
    WSACloseEvent(write_overlapped_.hEvent);
    memset(&write_overlapped_, 0xaf, sizeof(write_overlapped_));
  }
  
  void TCPSocketWin::Core::WatchForRead() {
    // We grab an extra reference because there is an IO operation in progress.
    // Balanced in ReadDelegate::OnObjectSignaled().
    AddRef();
    read_watcher_.StartWatchingOnce(read_overlapped_.hEvent, &reader_);
  }
  
  void TCPSocketWin::Core::WatchForWrite() {
    // We grab an extra reference because there is an IO operation in progress.
    // Balanced in WriteDelegate::OnObjectSignaled().
    AddRef();
    write_watcher_.StartWatchingOnce(write_overlapped_.hEvent, &writer_);
  }
  
  void TCPSocketWin::Core::ReadDelegate::OnObjectSignaled(HANDLE object) {
    DCHECK_EQ(object, core_->read_overlapped_.hEvent);
    if (core_->socket_) {
      if (core_->socket_->waiting_connect_)
        core_->socket_->DidCompleteConnect();
      else
        core_->socket_->DidSignalRead();
    }
  
    core_->Release();
  }
  
  void TCPSocketWin::Core::WriteDelegate::OnObjectSignaled(
      HANDLE object) {
    DCHECK_EQ(object, core_->write_overlapped_.hEvent);
    if (core_->socket_)
      core_->socket_->DidCompleteWrite();
  
    core_->Release();
  }
  
  //-----------------------------------------------------------------------------
  
  TCPSocketWin::TCPSocketWin(
      std::unique_ptr<SocketPerformanceWatcher> socket_performance_watcher,
      net::NetLog* net_log,
      const net::NetLog::Source& source)
      : socket_(INVALID_SOCKET),
        socket_performance_watcher_(std::move(socket_performance_watcher)),
        accept_event_(WSA_INVALID_EVENT),
        accept_socket_(NULL),
        accept_address_(NULL),
        waiting_connect_(false),
        waiting_read_(false),
        waiting_write_(false),
        connect_os_error_(0),
        logging_multiple_connect_attempts_(false),
        net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_SOCKET)) {
    net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
                        source.ToEventParametersCallback());
    EnsureWinsockInit();
  }
  
  TCPSocketWin::~TCPSocketWin() {
    Close();
    net_log_.EndEvent(NetLog::TYPE_SOCKET_ALIVE);
  }
  
  int TCPSocketWin::Open(AddressFamily family) {
    DCHECK(CalledOnValidThread());
    DCHECK_EQ(socket_, INVALID_SOCKET);
  
    socket_ = CreatePlatformSocket(ConvertAddressFamily(family), SOCK_STREAM,
                                   IPPROTO_TCP);
    if (socket_ == INVALID_SOCKET) {
      PLOG(ERROR) << "CreatePlatformSocket() returned an error";
      return MapSystemError(WSAGetLastError());
    }
  
    if (!base::SetNonBlocking(socket_)) {
      int result = MapSystemError(WSAGetLastError());
      Close();
      return result;
    }
  
    return OK;
  }
  
  int TCPSocketWin::AdoptConnectedSocket(SOCKET socket,
                                         const IPEndPoint& peer_address) {
    DCHECK(CalledOnValidThread());
    DCHECK_EQ(socket_, INVALID_SOCKET);
    DCHECK(!core_.get());
  
    socket_ = socket;
  
    if (!base::SetNonBlocking(socket_)) {
      int result = MapSystemError(WSAGetLastError());
      Close();
      return result;
    }
  
    core_ = new Core(this);
    peer_address_.reset(new IPEndPoint(peer_address));
  
    return OK;
  }
  
  int TCPSocketWin::AdoptListenSocket(SOCKET socket) {
    DCHECK(CalledOnValidThread());
    DCHECK_EQ(socket_, INVALID_SOCKET);
  
    socket_ = socket;
  
    if (!base::SetNonBlocking(socket_)) {
      int result = MapSystemError(WSAGetLastError());
      Close();
      return result;
    }
  
    // |core_| is not needed for sockets that are used to accept connections.
    // The operation here is more like Open but with an existing socket.
  
    return OK;
  }
  
  int TCPSocketWin::Bind(const IPEndPoint& address) {
    DCHECK(CalledOnValidThread());
    DCHECK_NE(socket_, INVALID_SOCKET);
  
    SockaddrStorage storage;
    if (!address.ToSockAddr(storage.addr, &storage.addr_len))
      return ERR_ADDRESS_INVALID;
  
    int result = bind(socket_, storage.addr, storage.addr_len);
    if (result < 0) {
      PLOG(ERROR) << "bind() returned an error";
      return MapSystemError(WSAGetLastError());
    }
  
    return OK;
  }
  
  int TCPSocketWin::Listen(int backlog) {
    DCHECK(CalledOnValidThread());
    DCHECK_GT(backlog, 0);
    DCHECK_NE(socket_, INVALID_SOCKET);
    DCHECK_EQ(accept_event_, WSA_INVALID_EVENT);
  
    accept_event_ = WSACreateEvent();
    if (accept_event_ == WSA_INVALID_EVENT) {
      PLOG(ERROR) << "WSACreateEvent()";
      return MapSystemError(WSAGetLastError());
    }
  
    int result = listen(socket_, backlog);
    if (result < 0) {
      PLOG(ERROR) << "listen() returned an error";
      return MapSystemError(WSAGetLastError());
    }
  
    return OK;
  }
  
  int TCPSocketWin::Accept(std::unique_ptr<TCPSocketWin>* socket,
                           IPEndPoint* address,
                           const CompletionCallback& callback) {
    DCHECK(CalledOnValidThread());
    DCHECK(socket);
    DCHECK(address);
    DCHECK(!callback.is_null());
    DCHECK(accept_callback_.is_null());
  
    net_log_.BeginEvent(NetLog::TYPE_TCP_ACCEPT);
  
    int result = AcceptInternal(socket, address);
  
    if (result == ERR_IO_PENDING) {
      // Start watching.
      WSAEventSelect(socket_, accept_event_, FD_ACCEPT);
      accept_watcher_.StartWatchingOnce(accept_event_, this);
  
      accept_socket_ = socket;
      accept_address_ = address;
      accept_callback_ = callback;
    }
  
    return result;
  }
  
  int TCPSocketWin::Connect(const IPEndPoint& address,
                            const CompletionCallback& callback) {
    DCHECK(CalledOnValidThread());
    DCHECK_NE(socket_, INVALID_SOCKET);
    DCHECK(!waiting_connect_);
  
    // |peer_address_| and |core_| will be non-NULL if Connect() has been called.
    // Unless Close() is called to reset the internal state, a second call to
    // Connect() is not allowed.
    // Please note that we enforce this even if the previous Connect() has
    // completed and failed. Although it is allowed to connect the same |socket_|
    // again after a connection attempt failed on Windows, it results in
    // unspecified behavior according to POSIX. Therefore, we make it behave in
    // the same way as TCPSocketPosix.
    DCHECK(!peer_address_ && !core_.get());
  
    if (!logging_multiple_connect_attempts_)
      LogConnectBegin(AddressList(address));
  
    peer_address_.reset(new IPEndPoint(address));
  
    int rv = DoConnect();
    if (rv == ERR_IO_PENDING) {
      // Synchronous operation not supported.
      DCHECK(!callback.is_null());
      read_callback_ = callback;
      waiting_connect_ = true;
    } else {
      DoConnectComplete(rv);
    }
  
    return rv;
  }
  
  bool TCPSocketWin::IsConnected() const {
    DCHECK(CalledOnValidThread());
  
    if (socket_ == INVALID_SOCKET || waiting_connect_)
      return false;
  
    if (waiting_read_)
      return true;
  
    // Check if connection is alive.
    char c;
    int rv = recv(socket_, &c, 1, MSG_PEEK);
    if (rv == 0)
      return false;
    if (rv == SOCKET_ERROR && WSAGetLastError() != WSAEWOULDBLOCK)
      return false;
  
    return true;
  }
  
  bool TCPSocketWin::IsConnectedAndIdle() const {
    DCHECK(CalledOnValidThread());
  
    if (socket_ == INVALID_SOCKET || waiting_connect_)
      return false;
  
    if (waiting_read_)
      return true;
  
    // Check if connection is alive and we haven't received any data
    // unexpectedly.
    char c;
    int rv = recv(socket_, &c, 1, MSG_PEEK);
    if (rv >= 0)
      return false;
    if (WSAGetLastError() != WSAEWOULDBLOCK)
      return false;
  
    return true;
  }
  
  int TCPSocketWin::Read(IOBuffer* buf,
                         int buf_len,
                         const CompletionCallback& callback) {
    DCHECK(CalledOnValidThread());
    DCHECK_NE(socket_, INVALID_SOCKET);
    DCHECK(!waiting_read_);
    CHECK(read_callback_.is_null());
    DCHECK(!core_->read_iobuffer_.get());
  
    return DoRead(buf, buf_len, callback);
  }
  
  int TCPSocketWin::Write(IOBuffer* buf,
                          int buf_len,
                          const CompletionCallback& callback) {
    DCHECK(CalledOnValidThread());
    DCHECK_NE(socket_, INVALID_SOCKET);
    DCHECK(!waiting_write_);
    CHECK(write_callback_.is_null());
    DCHECK_GT(buf_len, 0);
    DCHECK(!core_->write_iobuffer_.get());
  
    WSABUF write_buffer;
    write_buffer.len = buf_len;
    write_buffer.buf = buf->data();
  
    // TODO(wtc): Remove the assertion after enough testing.
    AssertEventNotSignaled(core_->write_overlapped_.hEvent);
    DWORD num;
    int rv = WSASend(socket_, &write_buffer, 1, &num, 0,
                     &core_->write_overlapped_, NULL);
    if (rv == 0) {
      if (ResetEventIfSignaled(core_->write_overlapped_.hEvent)) {
        rv = static_cast<int>(num);
        if (rv > buf_len || rv < 0) {
          // It seems that some winsock interceptors report that more was written
          // than was available. Treat this as an error.  http://crbug.com/27870
          LOG(ERROR) << "Detected broken LSP: Asked to write " << buf_len
                     << " bytes, but " << rv << " bytes reported.";
          return ERR_WINSOCK_UNEXPECTED_WRITTEN_BYTES;
        }
        net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_SENT, rv,
                                      buf->data());
        NetworkActivityMonitor::GetInstance()->IncrementBytesSent(rv);
        return rv;
      }
    } else {
      int os_error = WSAGetLastError();
      if (os_error != WSA_IO_PENDING) {
        int net_error = MapSystemError(os_error);
        net_log_.AddEvent(NetLog::TYPE_SOCKET_WRITE_ERROR,
                          CreateNetLogSocketErrorCallback(net_error, os_error));
        return net_error;
      }
    }
    waiting_write_ = true;
    write_callback_ = callback;
    core_->write_iobuffer_ = buf;
    core_->write_buffer_length_ = buf_len;
    core_->WatchForWrite();
    return ERR_IO_PENDING;
  }
  
  int TCPSocketWin::GetLocalAddress(IPEndPoint* address) const {
    DCHECK(CalledOnValidThread());
    DCHECK(address);
  
    SockaddrStorage storage;
    if (getsockname(socket_, storage.addr, &storage.addr_len))
      return MapSystemError(WSAGetLastError());
    if (!address->FromSockAddr(storage.addr, storage.addr_len))
      return ERR_ADDRESS_INVALID;
  
    return OK;
  }
  
  int TCPSocketWin::GetPeerAddress(IPEndPoint* address) const {
    DCHECK(CalledOnValidThread());
    DCHECK(address);
    if (!IsConnected())
      return ERR_SOCKET_NOT_CONNECTED;
    *address = *peer_address_;
    return OK;
  }
  
  int TCPSocketWin::SetDefaultOptionsForServer() {
    return SetExclusiveAddrUse();
  }
  
  void TCPSocketWin::SetDefaultOptionsForClient() {
    SetTCPNoDelay(socket_, /*no_delay=*/true);
    SetTCPKeepAlive(socket_, true, kTCPKeepAliveSeconds);
  }
  
  int TCPSocketWin::SetExclusiveAddrUse() {
    // On Windows, a bound end point can be hijacked by another process by
    // setting SO_REUSEADDR. Therefore a Windows-only option SO_EXCLUSIVEADDRUSE
    // was introduced in Windows NT 4.0 SP4. If the socket that is bound to the
    // end point has SO_EXCLUSIVEADDRUSE enabled, it is not possible for another
    // socket to forcibly bind to the end point until the end point is unbound.
    // It is recommend that all server applications must use SO_EXCLUSIVEADDRUSE.
    // MSDN: http://goo.gl/M6fjQ.
    //
    // Unlike on *nix, on Windows a TCP server socket can always bind to an end
    // point in TIME_WAIT state without setting SO_REUSEADDR, therefore it is not
    // needed here.
    //
    // SO_EXCLUSIVEADDRUSE will prevent a TCP client socket from binding to an end
    // point in TIME_WAIT status. It does not have this effect for a TCP server
    // socket.
  
    BOOL true_value = 1;
    int rv = setsockopt(socket_, SOL_SOCKET, SO_EXCLUSIVEADDRUSE,
                        reinterpret_cast<const char*>(&true_value),
                        sizeof(true_value));
    if (rv < 0)
      return MapSystemError(errno);
    return OK;
  }
  
  int TCPSocketWin::SetReceiveBufferSize(int32_t size) {
    DCHECK(CalledOnValidThread());
    return SetSocketReceiveBufferSize(socket_, size);
  }
  
  int TCPSocketWin::SetSendBufferSize(int32_t size) {
    DCHECK(CalledOnValidThread());
    return SetSocketSendBufferSize(socket_, size);
  }
  
  bool TCPSocketWin::SetKeepAlive(bool enable, int delay) {
    return SetTCPKeepAlive(socket_, enable, delay);
  }
  
  bool TCPSocketWin::SetNoDelay(bool no_delay) {
    return SetTCPNoDelay(socket_, no_delay);
  }
  
  void TCPSocketWin::Close() {
    DCHECK(CalledOnValidThread());
  
    if (socket_ != INVALID_SOCKET) {
      // Only log the close event if there's actually a socket to close.
      net_log_.AddEvent(NetLog::EventType::TYPE_SOCKET_CLOSED);
  
      // Note: don't use CancelIo to cancel pending IO because it doesn't work
      // when there is a Winsock layered service provider.
  
      // In most socket implementations, closing a socket results in a graceful
      // connection shutdown, but in Winsock we have to call shutdown explicitly.
      // See the MSDN page "Graceful Shutdown, Linger Options, and Socket Closure"
      // at http://msdn.microsoft.com/en-us/library/ms738547.aspx
      shutdown(socket_, SD_SEND);
  
      // This cancels any pending IO.
      if (closesocket(socket_) < 0)
        PLOG(ERROR) << "closesocket";
      socket_ = INVALID_SOCKET;
    }
  
    if (!accept_callback_.is_null()) {
      accept_watcher_.StopWatching();
      accept_socket_ = NULL;
      accept_address_ = NULL;
      accept_callback_.Reset();
    }
  
    if (accept_event_) {
      WSACloseEvent(accept_event_);
      accept_event_ = WSA_INVALID_EVENT;
    }
  
    if (core_.get()) {
      if (waiting_connect_) {
        // We closed the socket, so this notification will never come.
        // From MSDN' WSAEventSelect documentation:
        // "Closing a socket with closesocket also cancels the association and
        // selection of network events specified in WSAEventSelect for the
        // socket".
        core_->Release();
      }
      core_->Detach();
      core_ = NULL;
    }
  
    waiting_connect_ = false;
    waiting_read_ = false;
    waiting_write_ = false;
  
    read_callback_.Reset();
    write_callback_.Reset();
    peer_address_.reset();
    connect_os_error_ = 0;
  }
  
  void TCPSocketWin::DetachFromThread() {
    base::NonThreadSafe::DetachFromThread();
  }
  
  void TCPSocketWin::StartLoggingMultipleConnectAttempts(
      const AddressList& addresses) {
    if (!logging_multiple_connect_attempts_) {
      logging_multiple_connect_attempts_ = true;
      LogConnectBegin(addresses);
    } else {
      NOTREACHED();
    }
  }
  
  void TCPSocketWin::EndLoggingMultipleConnectAttempts(int net_error) {
    if (logging_multiple_connect_attempts_) {
      LogConnectEnd(net_error);
      logging_multiple_connect_attempts_ = false;
    } else {
      NOTREACHED();
    }
  }
  
  int TCPSocketWin::AcceptInternal(std::unique_ptr<TCPSocketWin>* socket,
                                   IPEndPoint* address) {
    SockaddrStorage storage;
    int new_socket = accept(socket_, storage.addr, &storage.addr_len);
    if (new_socket < 0) {
      int net_error = MapSystemError(WSAGetLastError());
      if (net_error != ERR_IO_PENDING)
        net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_ACCEPT, net_error);
      return net_error;
    }
  
    IPEndPoint ip_end_point;
    if (!ip_end_point.FromSockAddr(storage.addr, storage.addr_len)) {
      NOTREACHED();
      if (closesocket(new_socket) < 0)
        PLOG(ERROR) << "closesocket";
      int net_error = ERR_ADDRESS_INVALID;
      net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_ACCEPT, net_error);
      return net_error;
    }
    std::unique_ptr<TCPSocketWin> tcp_socket(
        new TCPSocketWin(NULL, net_log_.net_log(), net_log_.source()));
    int adopt_result = tcp_socket->AdoptConnectedSocket(new_socket, ip_end_point);
    if (adopt_result != OK) {
      net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_ACCEPT, adopt_result);
      return adopt_result;
    }
    *socket = std::move(tcp_socket);
    *address = ip_end_point;
    net_log_.EndEvent(NetLog::TYPE_TCP_ACCEPT,
                      CreateNetLogIPEndPointCallback(&ip_end_point));
    return OK;
  }
  
  void TCPSocketWin::OnObjectSignaled(HANDLE object) {
    WSANETWORKEVENTS ev;
    if (WSAEnumNetworkEvents(socket_, accept_event_, &ev) == SOCKET_ERROR) {
      PLOG(ERROR) << "WSAEnumNetworkEvents()";
      return;
    }
  
    if (ev.lNetworkEvents & FD_ACCEPT) {
      int result = AcceptInternal(accept_socket_, accept_address_);
      if (result != ERR_IO_PENDING) {
        accept_socket_ = NULL;
        accept_address_ = NULL;
        base::ResetAndReturn(&accept_callback_).Run(result);
      }
    } else {
      // This happens when a client opens a connection and closes it before we
      // have a chance to accept it.
      DCHECK(ev.lNetworkEvents == 0);
  
      // Start watching the next FD_ACCEPT event.
      WSAEventSelect(socket_, accept_event_, FD_ACCEPT);
      accept_watcher_.StartWatchingOnce(accept_event_, this);
    }
  }
  
  int TCPSocketWin::DoConnect() {
    DCHECK_EQ(connect_os_error_, 0);
    DCHECK(!core_.get());
  
    net_log_.BeginEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT,
                        CreateNetLogIPEndPointCallback(peer_address_.get()));
  
    core_ = new Core(this);
  
    // WSAEventSelect sets the socket to non-blocking mode as a side effect.
    // Our connect() and recv() calls require that the socket be non-blocking.
    WSAEventSelect(socket_, core_->read_overlapped_.hEvent, FD_CONNECT);
  
    SockaddrStorage storage;
    if (!peer_address_->ToSockAddr(storage.addr, &storage.addr_len))
      return ERR_ADDRESS_INVALID;
  
    int result;
    {
      // TODO(ricea): Remove ScopedTracker below once crbug.com/436634 is fixed.
      tracked_objects::ScopedTracker tracking_profile(
          FROM_HERE_WITH_EXPLICIT_FUNCTION("436634 connect()"));
      result = connect(socket_, storage.addr, storage.addr_len);
    }
  
    if (!result) {
      // Connected without waiting!
      //
      // The MSDN page for connect says:
      //   With a nonblocking socket, the connection attempt cannot be completed
      //   immediately. In this case, connect will return SOCKET_ERROR, and
      //   WSAGetLastError will return WSAEWOULDBLOCK.
      // which implies that for a nonblocking socket, connect never returns 0.
      // It's not documented whether the event object will be signaled or not
      // if connect does return 0.  So the code below is essentially dead code
      // and we don't know if it's correct.
      NOTREACHED();
  
      if (ResetEventIfSignaled(core_->read_overlapped_.hEvent))
        return OK;
    } else {
      int os_error = WSAGetLastError();
      if (os_error != WSAEWOULDBLOCK) {
        LOG(ERROR) << "connect failed: " << os_error;
        connect_os_error_ = os_error;
        int rv = MapConnectError(os_error);
        CHECK_NE(ERR_IO_PENDING, rv);
        return rv;
      }
    }
  
    // TODO(ricea): Remove ScopedTracker below once crbug.com/436634 is fixed.
    tracked_objects::ScopedTracker tracking_profile(
        FROM_HERE_WITH_EXPLICIT_FUNCTION("436634 WatchForRead()"));
  
    core_->WatchForRead();
    return ERR_IO_PENDING;
  }
  
  void TCPSocketWin::DoConnectComplete(int result) {
    // Log the end of this attempt (and any OS error it threw).
    int os_error = connect_os_error_;
    connect_os_error_ = 0;
    if (result != OK) {
      net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT,
                        NetLog::IntCallback("os_error", os_error));
    } else {
      net_log_.EndEvent(NetLog::TYPE_TCP_CONNECT_ATTEMPT);
    }
  
    if (!logging_multiple_connect_attempts_)
      LogConnectEnd(result);
  }
  
  void TCPSocketWin::LogConnectBegin(const AddressList& addresses) {
    net_log_.BeginEvent(NetLog::TYPE_TCP_CONNECT,
                        addresses.CreateNetLogCallback());
  }
  
  void TCPSocketWin::LogConnectEnd(int net_error) {
    if (net_error == OK)
      UpdateConnectionTypeHistograms(CONNECTION_ANY);
  
    if (net_error != OK) {
      net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_CONNECT, net_error);
      return;
    }
  
    struct sockaddr_storage source_address;
    socklen_t addrlen = sizeof(source_address);
    int rv = getsockname(
        socket_, reinterpret_cast<struct sockaddr*>(&source_address), &addrlen);
    if (rv != 0) {
      LOG(ERROR) << "getsockname() [rv: " << rv
                 << "] error: " << WSAGetLastError();
      NOTREACHED();
      net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_CONNECT, rv);
      return;
    }
  
    net_log_.EndEvent(
        NetLog::TYPE_TCP_CONNECT,
        CreateNetLogSourceAddressCallback(
            reinterpret_cast<const struct sockaddr*>(&source_address),
            sizeof(source_address)));
  }
  
  int TCPSocketWin::DoRead(IOBuffer* buf, int buf_len,
                           const CompletionCallback& callback) {
    if (!core_->non_blocking_reads_initialized_) {
      WSAEventSelect(socket_, core_->read_overlapped_.hEvent,
                     FD_READ | FD_CLOSE);
      core_->non_blocking_reads_initialized_ = true;
    }
    int rv = recv(socket_, buf->data(), buf_len, 0);
    if (rv == SOCKET_ERROR) {
      int os_error = WSAGetLastError();
      if (os_error != WSAEWOULDBLOCK) {
        int net_error = MapSystemError(os_error);
        net_log_.AddEvent(
            NetLog::TYPE_SOCKET_READ_ERROR,
            CreateNetLogSocketErrorCallback(net_error, os_error));
        return net_error;
      }
    } else {
      net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_RECEIVED, rv,
                                    buf->data());
      NetworkActivityMonitor::GetInstance()->IncrementBytesReceived(rv);
      return rv;
    }
  
    waiting_read_ = true;
    read_callback_ = callback;
    core_->read_iobuffer_ = buf;
    core_->read_buffer_length_ = buf_len;
    core_->WatchForRead();
    return ERR_IO_PENDING;
  }
  
  void TCPSocketWin::DidCompleteConnect() {
    DCHECK(waiting_connect_);
    DCHECK(!read_callback_.is_null());
    int result;
  
    WSANETWORKEVENTS events;
    int rv;
    {
      // TODO(pkasting): Remove ScopedTracker below once crbug.com/462784 is
      // fixed.
      tracked_objects::ScopedTracker tracking_profile1(
          FROM_HERE_WITH_EXPLICIT_FUNCTION(
              "462784 TCPSocketWin::DidCompleteConnect -> WSAEnumNetworkEvents"));
      rv = WSAEnumNetworkEvents(socket_, core_->read_overlapped_.hEvent, &events);
    }
    int os_error = 0;
    if (rv == SOCKET_ERROR) {
      NOTREACHED();
      os_error = WSAGetLastError();
      result = MapSystemError(os_error);
    } else if (events.lNetworkEvents & FD_CONNECT) {
      os_error = events.iErrorCode[FD_CONNECT_BIT];
      result = MapConnectError(os_error);
    } else {
      NOTREACHED();
      result = ERR_UNEXPECTED;
    }
  
    connect_os_error_ = os_error;
    DoConnectComplete(result);
    waiting_connect_ = false;
  
    // TODO(pkasting): Remove ScopedTracker below once crbug.com/462784 is fixed.
    tracked_objects::ScopedTracker tracking_profile4(
        FROM_HERE_WITH_EXPLICIT_FUNCTION(
            "462784 TCPSocketWin::DidCompleteConnect -> read_callback_"));
    DCHECK_NE(result, ERR_IO_PENDING);
    base::ResetAndReturn(&read_callback_).Run(result);
  }
  
  void TCPSocketWin::DidCompleteWrite() {
    DCHECK(waiting_write_);
    DCHECK(!write_callback_.is_null());
  
    DWORD num_bytes, flags;
    BOOL ok = WSAGetOverlappedResult(socket_, &core_->write_overlapped_,
                                     &num_bytes, FALSE, &flags);
    WSAResetEvent(core_->write_overlapped_.hEvent);
    waiting_write_ = false;
    int rv;
    if (!ok) {
      int os_error = WSAGetLastError();
      rv = MapSystemError(os_error);
      net_log_.AddEvent(NetLog::TYPE_SOCKET_WRITE_ERROR,
                        CreateNetLogSocketErrorCallback(rv, os_error));
    } else {
      rv = static_cast<int>(num_bytes);
      if (rv > core_->write_buffer_length_ || rv < 0) {
        // It seems that some winsock interceptors report that more was written
        // than was available. Treat this as an error.  http://crbug.com/27870
        LOG(ERROR) << "Detected broken LSP: Asked to write "
                   << core_->write_buffer_length_ << " bytes, but " << rv
                   << " bytes reported.";
        rv = ERR_WINSOCK_UNEXPECTED_WRITTEN_BYTES;
      } else {
        net_log_.AddByteTransferEvent(NetLog::TYPE_SOCKET_BYTES_SENT, num_bytes,
                                      core_->write_iobuffer_->data());
        NetworkActivityMonitor::GetInstance()->IncrementBytesSent(num_bytes);
      }
    }
  
    core_->write_iobuffer_ = NULL;
  
    DCHECK_NE(rv, ERR_IO_PENDING);
    base::ResetAndReturn(&write_callback_).Run(rv);
  }
  
  void TCPSocketWin::DidSignalRead() {
    DCHECK(waiting_read_);
    DCHECK(!read_callback_.is_null());
  
    int os_error = 0;
    WSANETWORKEVENTS network_events;
    int rv = WSAEnumNetworkEvents(socket_, core_->read_overlapped_.hEvent,
                                  &network_events);
    if (rv == SOCKET_ERROR) {
      os_error = WSAGetLastError();
      rv = MapSystemError(os_error);
    } else if (network_events.lNetworkEvents) {
      // TODO(pkasting): Remove ScopedTracker below once crbug.com/462778 is
      // fixed.
      tracked_objects::ScopedTracker tracking_profile2(
          FROM_HERE_WITH_EXPLICIT_FUNCTION(
              "462778 TCPSocketWin::DidSignalRead -> DoRead"));
      DCHECK_EQ(network_events.lNetworkEvents & ~(FD_READ | FD_CLOSE), 0);
      // If network_events.lNetworkEvents is FD_CLOSE and
      // network_events.iErrorCode[FD_CLOSE_BIT] is 0, it is a graceful
      // connection closure. It is tempting to directly set rv to 0 in
      // this case, but the MSDN pages for WSAEventSelect and
      // WSAAsyncSelect recommend we still call DoRead():
      //   FD_CLOSE should only be posted after all data is read from a
      //   socket, but an application should check for remaining data upon
      //   receipt of FD_CLOSE to avoid any possibility of losing data.
      //
      // If network_events.iErrorCode[FD_READ_BIT] or
      // network_events.iErrorCode[FD_CLOSE_BIT] is nonzero, still call
      // DoRead() because recv() reports a more accurate error code
      // (WSAECONNRESET vs. WSAECONNABORTED) when the connection was
      // reset.
      rv = DoRead(core_->read_iobuffer_.get(), core_->read_buffer_length_,
                  read_callback_);
      if (rv == ERR_IO_PENDING)
        return;
    } else {
      // This may happen because Read() may succeed synchronously and
      // consume all the received data without resetting the event object.
      core_->WatchForRead();
      return;
    }
  
    waiting_read_ = false;
    core_->read_iobuffer_ = NULL;
    core_->read_buffer_length_ = 0;
  
    DCHECK_NE(rv, ERR_IO_PENDING);
    base::ResetAndReturn(&read_callback_).Run(rv);
  }
  
  bool TCPSocketWin::GetEstimatedRoundTripTime(base::TimeDelta* out_rtt) const {
    DCHECK(out_rtt);
    // TODO(bmcquade): Consider implementing using
    // GetPerTcpConnectionEStats/GetPerTcp6ConnectionEStats.
    return false;
  }
  
  }  // namespace net
  