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 if (sotype == syscall.SOCK_DGRAM || sotype == syscall.SOCK_RAW) && family != syscall.AF_UNIX && family != syscall.AF_INET6 {
20 // Allow broadcast.
21 return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1))
22 }
23 return nil
24 }
25 26 func setDefaultListenerSockopts(s syscall.Handle) error {
27 // Windows will reuse recently-used addresses by default.
28 // SO_REUSEADDR should not be used here, as it allows
29 // a socket to forcibly bind to a port in use by another socket.
30 // This could lead to a non-deterministic behavior, where
31 // connection requests over the port cannot be guaranteed
32 // to be handled by the correct socket.
33 return nil
34 }
35 36 func setDefaultMulticastSockopts(s syscall.Handle) error {
37 // Allow multicast UDP and raw IP datagram sockets to listen
38 // concurrently across multiple listeners.
39 return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1))
40 }
41