net/socket/socket_options.cc

// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/socket/socket_options.h"

#include <cerrno>

#include "build/build_config.h"
#include "net/base/net_errors.h"

#if BUILDFLAG(IS_WIN)
#include <winsock2.h>
#include <ws2tcpip.h>
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <sys/socket.h>
#endif

namespace net {

int SetTCPNoDelay(SocketDescriptor fd, bool no_delay) {
#if BUILDFLAG(IS_WIN)
  BOOL on = no_delay ? TRUE : FALSE;
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  int on = no_delay ? 1 : 0;
#endif
  int rv = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY,
                      reinterpret_cast<const char*>(&on), sizeof(on));
  return rv == -1 ? MapSystemError(errno) : OK;
}

int SetReuseAddr(SocketDescriptor fd, bool reuse) {
// SO_REUSEADDR is useful for server sockets to bind to a recently unbound
// port. When a socket is closed, the end point changes its state to TIME_WAIT
// and wait for 2 MSL (maximum segment lifetime) to ensure the remote peer
// acknowledges its closure. For server sockets, it is usually safe to
// bind to a TIME_WAIT end point immediately, which is a widely adopted
// behavior.
//
// Note that on *nix, SO_REUSEADDR does not enable the socket (which can be
// either TCP or UDP) to bind to an end point that is already bound by another
// socket. To do that one must set SO_REUSEPORT instead. This option is not
// provided on Linux prior to 3.9.
//
// SO_REUSEPORT is provided in MacOS X and iOS.
#if BUILDFLAG(IS_WIN)
  BOOL boolean_value = reuse ? TRUE : FALSE;
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  int boolean_value = reuse ? 1 : 0;
#endif
  int rv = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
                      reinterpret_cast<const char*>(&boolean_value),
                      sizeof(boolean_value));
  return rv == -1 ? MapSystemError(errno) : OK;
}

int SetSocketReceiveBufferSize(SocketDescriptor fd, int32_t size) {
  int rv = setsockopt(fd, SOL_SOCKET, SO_RCVBUF,
                      reinterpret_cast<const char*>(&size), sizeof(size));
#if BUILDFLAG(IS_WIN)
  int os_error = WSAGetLastError();
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  int os_error = errno;
#endif
  int net_error = (rv == -1) ? MapSystemError(os_error) : OK;
  if (net_error != OK) {
    DLOG(ERROR) << "Could not set socket receive buffer size: " << net_error;
  }
  return net_error;
}

int SetSocketSendBufferSize(SocketDescriptor fd, int32_t size) {
  int rv = setsockopt(fd, SOL_SOCKET, SO_SNDBUF,
                      reinterpret_cast<const char*>(&size), sizeof(size));
#if BUILDFLAG(IS_WIN)
  int os_error = WSAGetLastError();
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  int os_error = errno;
#endif
  int net_error = (rv == -1) ? MapSystemError(os_error) : OK;
  if (net_error != OK) {
    DLOG(ERROR) << "Could not set socket send buffer size: " << net_error;
  }
  return net_error;
}

int SetIPv6Only(SocketDescriptor fd, bool ipv6_only) {
#if BUILDFLAG(IS_WIN)
  DWORD on = ipv6_only ? 1 : 0;
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  int on = ipv6_only ? 1 : 0;
#endif
  int rv = setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY,
                      reinterpret_cast<const char*>(&on), sizeof(on));
  return rv == -1 ? MapSystemError(errno) : OK;
}

}  // namespace net