libgo/go/net/sockopt_windows.go

   1 // Copyright 2011 The Go Authors.  All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package net
   6
   7 import (
   8         "os"
   9         "syscall"
  10 )
  11
  12 func setDefaultSockopts(s syscall.Handle, family, sotype int, ipv6only bool) error {
  13         if family == syscall.AF_INET6 && sotype != syscall.SOCK_RAW {
  14                 // Allow both IP versions even if the OS default
  15                 // is otherwise.  Note that some operating systems
  16                 // never admit this option.
  17                 syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, boolint(ipv6only))
  18         }
  19         // Allow broadcast.
  20         syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)
  21         return nil
  22 }
  23
  24 func setDefaultListenerSockopts(s syscall.Handle) error {
  25         // Windows will reuse recently-used addresses by default.
  26         // SO_REUSEADDR should not be used here, as it allows
  27         // a socket to forcibly bind to a port in use by another socket.
  28         // This could lead to a non-deterministic behavior, where
  29         // connection requests over the port cannot be guaranteed
  30         // to be handled by the correct socket.
  31         return nil
  32 }
  33
  34 func setDefaultMulticastSockopts(s syscall.Handle) error {
  35         // Allow multicast UDP and raw IP datagram sockets to listen
  36         // concurrently across multiple listeners.
  37         return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1))
  38 }