text: // Copyright 2011 The Go Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style
  // license that can be found in the LICENSE file.
  
  package net
  
  import (
  	"os"
  	"syscall"
  )
  
  func setDefaultSockopts(s, family, sotype int, ipv6only bool) error {
  	if family == syscall.AF_INET6 && sotype != syscall.SOCK_RAW {
  		// Allow both IP versions even if the OS default
  		// is otherwise. Note that some operating systems
  		// never admit this option.
  		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, boolint(ipv6only))
  	}
  	// Allow broadcast.
  	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1))
  }
  
  func setDefaultListenerSockopts(s int) error {
  	// Allow reuse of recently-used addresses.
  	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1))
  }
  
  func setDefaultMulticastSockopts(s int) error {
  	// Allow multicast UDP and raw IP datagram sockets to listen
  	// concurrently across multiple listeners.
  	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1))
  }
  