Golang syscall.SetsockoptInt函数代码示例

func advert(_ net.PacketConn, src, dst net.IP, p *net.IPNet) error {
	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
	if err != nil {
		return err
	}
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)
	pdst := dst
	if *useLimited && runtime.GOOS == "freebsd" {
		dst = directed(p)
		syscall.SetsockoptInt(s, syscall.IPPROTO_IP, 0x17, 1) // IP_ONESBCAST
	}
	sa := &syscall.SockaddrInet4{Port: *port}
	copy(sa.Addr[:], src.To4())
	if err := syscall.Bind(s, sa); err != nil {
		syscall.Close(s)
		return err
	}
	f := os.NewFile(uintptr(s), fmt.Sprintf("udp:%v->", src))
	c, err := net.FilePacketConn(f)
	f.Close()
	if err != nil {
		return err
	}
	defer c.Close()
	// If you are lucky, you can see that on some platform the
	// kernel sometimes transmits a wrong frame addressed to IPv4
	// limited broadcast address with some nexthop's link-layer
	// address on a broadcast-capable link.
	// In general, using BPF for transmitting IPv4 limited
	// broadcast addresses is a reasonable choice.
	_, err = c.WriteTo([]byte(fmt.Sprintf("%s-%v", runtime.GOOS, pdst)), &net.UDPAddr{IP: dst, Port: *port})
	return err
}

func main() {
	log.SetPrefix("")
	log.SetFlags(0)
	if os.Geteuid() != 0 {
		log.Fatal(errors.New("please run as root"))
	}
	fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_RAW, syscall.IPPROTO_RAW)
	check(err)
	if len(os.Args) < 3 {
		log.Fatal("usage: synflood <victimIP> <spoofedIP>")
	}
	raddr := net.ParseIP(os.Args[1])
	addr := syscall.SockaddrInet4{
		Port: 0,
		Addr: to4Array(raddr),
	}
	p := packet(raddr)
	switch runtime.GOOS {
	case "darwin", "dragonfly", "freebsd", "netbsd":
		// need to set explicitly
		check(syscall.SetsockoptInt(fd, syscall.IPPROTO_IP, syscall.IP_HDRINCL, 1))
		// no need to receive anything
		check(syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_RCVBUF, 1))
	case "linux":
		// no need to receive anything
		check(syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_RCVBUF, 0))
	}
	for {
		check(syscall.Sendto(fd, p, 0, &addr))
	}
}

func setDefaultMulticastSockopts(fd *netFD) {
	fd.incref()
	defer fd.decref()
	// Allow multicast UDP and raw IP datagram sockets to listen
	// concurrently across multiple listeners.
	syscall.SetsockoptInt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
	syscall.SetsockoptInt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
}

func SetOriginalDestOptions(fd int) error {
	if err := syscall.SetsockoptInt(fd, syscall.SOL_IP, syscall.IP_TRANSPARENT, 1); err != nil {
		return err
	}
	if err := syscall.SetsockoptInt(fd, syscall.SOL_IP, syscall.IP_RECVORIGDSTADDR, 1); err != nil {
		return err
	}
	return nil
}

func ka_intvl(fd int, d time.Duration) error {
	if d == 0 {
		return os.NewSyscallError("ka_intv", syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, 0))
	}

	// cargo cult from src/net/tcpsockopt_unix.go
	d += (time.Second - time.Nanosecond)
	return os.NewSyscallError("ka_intv", syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, int(d.Seconds())))
}

func setKernelSpecificSockopt(s syscall.Handle, f int) {
	// Allow broadcast.
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)

	if f == syscall.AF_INET6 {
		// using ip, tcp, udp, etc.
		// allow both protocols even if the OS default is otherwise.
		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0)
	}
}

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))
}

// Generic socket creation.
func socket(net string, f, p, t int, la, ra syscall.Sockaddr, toAddr func(syscall.Sockaddr) Addr) (fd *netFD, err os.Error) {
	// See ../syscall/exec.go for description of ForkLock.
	syscall.ForkLock.RLock()
	s, e := syscall.Socket(f, p, t)
	if e != 0 {
		syscall.ForkLock.RUnlock()
		return nil, os.Errno(e)
	}
	syscall.CloseOnExec(s)
	syscall.ForkLock.RUnlock()

	// Allow reuse of recently-used addresses.
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)

	// Allow broadcast.
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)

	if f == syscall.AF_INET6 {
		// using ip, tcp, udp, etc.
		// allow both protocols even if the OS default is otherwise.
		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0)
	}

	if la != nil {
		e = syscall.Bind(s, la)
		if e != 0 {
			closesocket(s)
			return nil, os.Errno(e)
		}
	}

	if ra != nil {
		e = syscall.Connect(s, ra)
		for e == syscall.EINTR {
			e = syscall.Connect(s, ra)
		}
		if e != 0 {
			closesocket(s)
			return nil, os.Errno(e)
		}
	}

	sa, _ := syscall.Getsockname(s)
	laddr := toAddr(sa)
	sa, _ = syscall.Getpeername(s)
	raddr := toAddr(sa)

	fd, err = newFD(s, f, p, net, laddr, raddr)
	if err != nil {
		closesocket(s)
		return nil, err
	}

	return fd, nil
}

// Listen returns TCP listener with SO_REUSEPORT option set.
//
// Only tcp4 network is supported.
//
// ErrNoReusePort error is returned if the system doesn't support SO_REUSEPORT.
func Listen(network, addr string) (l net.Listener, err error) {
	var (
		soType, fd int
		file       *os.File
		sockaddr   syscall.Sockaddr
	)

	if sockaddr, soType, err = getSockaddr(network, addr); err != nil {
		return nil, err
	}

	syscall.ForkLock.RLock()
	fd, err = syscall.Socket(soType, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
	if err == nil {
		syscall.CloseOnExec(fd)
	}
	syscall.ForkLock.RUnlock()
	if err != nil {
		return nil, err
	}

	if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, soReusePort, 1); err != nil {
		syscall.Close(fd)
		return nil, &ErrNoReusePort{err}
	}

	if err = syscall.Bind(fd, sockaddr); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	if err = syscall.Listen(fd, syscall.SOMAXCONN); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	name := fmt.Sprintf("reuseport.%d.%s.%s", os.Getpid(), network, addr)
	file = os.NewFile(uintptr(fd), name)
	if l, err = net.FileListener(file); err != nil {
		file.Close()
		return nil, err
	}

	if err = file.Close(); err != nil {
		l.Close()
		return nil, err
	}

	return l, err
}

func setDefaultSockopts(s syscall.Handle, f, t int) error {
	switch f {
	case syscall.AF_INET6:
		// 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, 0)
	}
	// Allow broadcast.
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)
	return nil
}

func setDefaultMulticastSockopts(s int) error {
	// Allow multicast UDP and raw IP datagram sockets to listen
	// concurrently across multiple listeners.
	if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
		return os.NewSyscallError("setsockopt", err)
	}
	// Allow reuse of recently-used ports.
	// This option is supported only in descendants of 4.4BSD,
	// to make an effective multicast application that requires
	// quick draw possible.
	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1))
}

func setKeepAlivePeriod(fd *netFD, d time.Duration) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	// The kernel expects seconds so round to next highest second.
	d += (time.Second - time.Nanosecond)
	secs := int(d.Seconds())
	if err := syscall.SetsockoptInt(fd.sysfd, syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, secs); err != nil {
		return os.NewSyscallError("setsockopt", err)
	}
	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(fd.sysfd, syscall.IPPROTO_TCP, syscall.TCP_KEEPIDLE, secs))
}

func setKernelSpecificSockopt(s, f int) {
	// Allow reuse of recently-used addresses and ports.
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)

	// Allow broadcast.
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)

	if f == syscall.AF_INET6 {
		// using ip, tcp, udp, etc.
		// allow both protocols even if the OS default is otherwise.
		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0)
	}
}

// NewReusablePortListener returns net.FileListener that created from
// a file discriptor for a socket with SO_REUSEPORT option.
func NewReusablePortListener(proto, addr string) (l net.Listener, err error) {
	var (
		soType, fd int
		file       *os.File
		sockaddr   syscall.Sockaddr
	)

	if sockaddr, soType, err = getSockaddr(proto, addr); err != nil {
		return nil, err
	}

	syscall.ForkLock.RLock()
	if fd, err = syscall.Socket(soType, syscall.SOCK_STREAM, syscall.IPPROTO_TCP); err != nil {
		return nil, err
	}
	syscall.ForkLock.RUnlock()

	if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	if err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, reusePort, 1); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	if err = syscall.Bind(fd, sockaddr); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	// Set backlog size to the maximum
	if err = syscall.Listen(fd, listenerBacklogMaxSize); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	file = os.NewFile(uintptr(fd), getSocketFileName(proto, addr))
	if l, err = net.FileListener(file); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	if err = file.Close(); err != nil {
		syscall.Close(fd)
		return nil, err
	}

	return l, err
}

func main() {
	flag.Parse()
	ip := net.ParseIP(*group)

	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
	if err != nil {
		log.Fatal(err)
	}
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
	syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
	lsa := syscall.SockaddrInet4{Port: *port}
	copy(lsa.Addr[:], ip.To4())
	if err := syscall.Bind(s, &lsa); err != nil {
		syscall.Close(s)
		log.Fatal(err)
	}
	f := os.NewFile(uintptr(s), "")
	c, err := net.FilePacketConn(f)
	f.Close()
	if err != nil {
		log.Fatal(err)
	}
	p := ipv4.NewPacketConn(c)
	defer p.Close()

	ift, err := net.Interfaces()
	if err != nil {
		log.Fatal(err)
	}
	avail := net.FlagMulticast | net.FlagUp
	for _, ifi := range ift {
		if ifi.Flags&avail != avail {
			continue
		}
		if err := p.JoinGroup(&ifi, &net.UDPAddr{IP: ip}); err != nil {
			log.Println(err, "on", ifi)
		}
	}

	log.Println(c.LocalAddr())
	go receiver(c)

	sig := make(chan os.Signal)
	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
	for {
		select {
		case <-sig:
			os.Exit(0)
		}
	}
}