// Copyright (c) 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 "net/socket/tcp_server_socket_win.h"

#include <mstcpip.h>

#include "net/base/ip_endpoint.h"
#include "net/base/net_errors.h"
#include "net/base/net_util.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"
#include "net/socket/tcp_client_socket.h"

namespace net {

TCPServerSocketWin::TCPServerSocketWin(net::NetLog* net_log,
                                       const net::NetLog::Source& source)
    : socket_(INVALID_SOCKET),
      socket_event_(WSA_INVALID_EVENT),
      accept_socket_(NULL),
      net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_SOCKET)) {
  net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
                      source.ToEventParametersCallback());
  EnsureWinsockInit();
}

TCPServerSocketWin::~TCPServerSocketWin() {
  Close();
  net_log_.EndEvent(NetLog::TYPE_SOCKET_ALIVE);
}

int TCPServerSocketWin::Listen(const IPEndPoint& address, int backlog) {
  DCHECK(CalledOnValidThread());
  DCHECK_GT(backlog, 0);
  DCHECK_EQ(socket_, INVALID_SOCKET);
  DCHECK_EQ(socket_event_, WSA_INVALID_EVENT);

  socket_event_ = WSACreateEvent();
  if (socket_event_ == WSA_INVALID_EVENT) {
    PLOG(ERROR) << "WSACreateEvent()";
    return ERR_FAILED;
  }

  socket_ = CreatePlatformSocket(address.GetSockAddrFamily(), SOCK_STREAM,
                                 IPPROTO_TCP);
  if (socket_ == INVALID_SOCKET) {
    PLOG(ERROR) << "socket() returned an error";
    return MapSystemError(WSAGetLastError());
  }

  if (SetNonBlocking(socket_)) {
    int result = MapSystemError(WSAGetLastError());
    Close();
    return result;
  }

  int result = SetSocketOptions();
  if (result != OK) {
    Close();
    return result;
  }

  SockaddrStorage storage;
  if (!address.ToSockAddr(storage.addr, &storage.addr_len)) {
    Close();
    return ERR_ADDRESS_INVALID;
  }

  result = bind(socket_, storage.addr, storage.addr_len);
  if (result < 0) {
    PLOG(ERROR) << "bind() returned an error";
    result = MapSystemError(WSAGetLastError());
    Close();
    return result;
  }

  result = listen(socket_, backlog);
  if (result < 0) {
    PLOG(ERROR) << "listen() returned an error";
    result = MapSystemError(WSAGetLastError());
    Close();
    return result;
  }

  return OK;
}

int TCPServerSocketWin::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_FAILED;

  return OK;
}

int TCPServerSocketWin::Accept(
    scoped_ptr<StreamSocket>* socket, const CompletionCallback& callback) {
  DCHECK(CalledOnValidThread());
  DCHECK(socket);
  DCHECK(!callback.is_null());
  DCHECK(accept_callback_.is_null());

  net_log_.BeginEvent(NetLog::TYPE_TCP_ACCEPT);

  int result = AcceptInternal(socket);

  if (result == ERR_IO_PENDING) {
    // Start watching
    WSAEventSelect(socket_, socket_event_, FD_ACCEPT);
    accept_watcher_.StartWatching(socket_event_, this);

    accept_socket_ = socket;
    accept_callback_ = callback;
  }

  return result;
}

int TCPServerSocketWin::SetSocketOptions() {
  // 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 TCPServerSocketWin::AcceptInternal(scoped_ptr<StreamSocket>* socket) {
  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 address;
  if (!address.FromSockAddr(storage.addr, storage.addr_len)) {
    NOTREACHED();
    if (closesocket(new_socket) < 0)
      PLOG(ERROR) << "closesocket";
    net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_ACCEPT, ERR_FAILED);
    return ERR_FAILED;
  }
  scoped_ptr<TCPClientSocket> tcp_socket(new TCPClientSocket(
      AddressList(address),
      net_log_.net_log(), net_log_.source()));
  int adopt_result = tcp_socket->AdoptSocket(new_socket);
  if (adopt_result != OK) {
    if (closesocket(new_socket) < 0)
      PLOG(ERROR) << "closesocket";
    net_log_.EndEventWithNetErrorCode(NetLog::TYPE_TCP_ACCEPT, adopt_result);
    return adopt_result;
  }
  socket->reset(tcp_socket.release());
  net_log_.EndEvent(NetLog::TYPE_TCP_ACCEPT,
                    CreateNetLogIPEndPointCallback(&address));
  return OK;
}

void TCPServerSocketWin::Close() {
  if (socket_ != INVALID_SOCKET) {
    if (closesocket(socket_) < 0)
      PLOG(ERROR) << "closesocket";
    socket_ = INVALID_SOCKET;
  }

  if (socket_event_) {
    WSACloseEvent(socket_event_);
    socket_event_ = WSA_INVALID_EVENT;
  }
}

void TCPServerSocketWin::OnObjectSignaled(HANDLE object) {
  WSANETWORKEVENTS ev;
  if (WSAEnumNetworkEvents(socket_, socket_event_, &ev) == SOCKET_ERROR) {
    PLOG(ERROR) << "WSAEnumNetworkEvents()";
    return;
  }

  if (ev.lNetworkEvents & FD_ACCEPT) {
    int result = AcceptInternal(accept_socket_);
    if (result != ERR_IO_PENDING) {
      accept_socket_ = NULL;
      CompletionCallback callback = accept_callback_;
      accept_callback_.Reset();
      callback.Run(result);
    }
  }
}

}  // namespace net