Golang syscall.Bind函數代碼示例

// NlConnect is same with libnl nl_connect. nl_close is required for releaseing internal fd.
func NlConnect(sk *NlSock, protocol int) error {
	if sk.Fd != -1 {
		return NLE_BAD_SOCK
	}
	if fd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_RAW|syscall.SOCK_CLOEXEC, protocol); err != nil {
		return err
	} else {
		sk.Fd = fd
	}
	if sk.Flags&NL_SOCK_BUFSIZE_SET != 0 {
		if err := NlSocketSetBufferSize(sk, 0, 0); err != nil {
			return err
		}
	}
	if sk.Local.Pid == 0 { // _nl_socket_is_local_port_unspecified
		pid := syscall.Getpid()

		var local *syscall.SockaddrNetlink
		for high := 1023; high > 0; high-- {
			if next := func() bool {
				pidLock.Lock()
				defer pidLock.Unlock()
				if _, exists := pidUsed[high]; !exists {
					pidUsed[high] = true
					return false
				}
				return true
			}(); next {
				continue
			}

			local = &syscall.SockaddrNetlink{
				Pid: uint32((high << 22) | (pid & 0x3FFFFF)),
			}
			if err := syscall.Bind(sk.Fd, local); err == nil {
				break
			} else if err != syscall.EADDRINUSE {
				return err
			} else {
				local = nil
			}
		}
		if local == nil {
			return NLE_EXIST
		}
		sk.Local = *local
		sk.Flags &^= NL_OWN_PORT
	} else {
		if err := syscall.Bind(sk.Fd, &(sk.Local)); err != nil {
			return err
		}
	}
	return nil
}

// Create a tcp socket, setting the TCP_FASTOPEN socket option.
func (s *TFOServer) Bind() (err error) {

	s.fd, err = syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM, 0)
	if err != nil {
		if err == syscall.ENOPROTOOPT {
			err = errors.New("TCP Fast Open server support is unavailable (unsupported kernel).")
		}
		return
	}

	err = syscall.SetsockoptInt(s.fd, syscall.SOL_TCP, TCP_FASTOPEN, 1)
	if err != nil {
		err = errors.New(fmt.Sprintf("Failed to set necessary TCP_FASTOPEN socket option: %s", err))
		return
	}

	sa := &syscall.SockaddrInet4{Addr: s.ServerAddr, Port: s.ServerPort}

	err = syscall.Bind(s.fd, sa)
	if err != nil {
		err = errors.New(fmt.Sprintf("Failed to bind to Addr: %v, Port: %d, Reason: %s", s.ServerAddr, s.ServerPort, err))
		return
	}

	log.Printf("Server: Bound to addr: %v, port: %d\n", s.ServerAddr, s.ServerPort)

	err = syscall.Listen(s.fd, LISTEN_BACKLOG)
	if err != nil {
		err = errors.New(fmt.Sprintf("Failed to listen: %s", err))
		return
	}

	return

}

func main() {
	fd, err := syscall.Socket(
		syscall.AF_NETLINK, syscall.SOCK_RAW,
		NETLINK_KOBJECT_UEVENT,
	)
	if err != nil {
		log.Println(err)
		return
	}

	nl := syscall.SockaddrNetlink{
		Family: syscall.AF_NETLINK,
		Pid:    uint32(os.Getpid()),
		Groups: 1,
	}
	err = syscall.Bind(fd, &nl)
	if err != nil {
		log.Println(err)
		return
	}

	b := make([]byte, UEVENT_BUFFER_SIZE*2)
	for {
		n, err2 := syscall.Read(fd, b)
		log.Println(n, err2)
		log.Println(b)
		act, dev, subsys := parseUBuffer(b)
		log.Println(act, dev, subsys)
	}
}

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 mcastOpen(bindAddr net.IP, port int, ifname string) (*ipv4.PacketConn, *net.UDPConn, error) {
	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP)
	if err != nil {
		log.Fatal(err)
	}
	if err := syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1); err != nil {
		log.Fatal(err)
	}
	//syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_REUSEPORT, 1)
	if err := syscall.SetsockoptString(s, syscall.SOL_SOCKET, syscall.SO_BINDTODEVICE, ifname); err != nil {
		log.Fatal(err)
	}

	lsa := syscall.SockaddrInet4{Port: port}
	copy(lsa.Addr[:], bindAddr.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)
	}
	u := c.(*net.UDPConn)
	p := ipv4.NewPacketConn(c)

	return p, u, nil
}

func probeIPv6Stack() (supportsIPv6, supportsIPv4map bool) {
	var probes = []struct {
		laddr net.TCPAddr
		value int
		ok    bool
	}{
		// IPv6 communication capability
		{laddr: net.TCPAddr{IP: net.ParseIP("::1")}, value: 1},
		// IPv6 IPv4-mapped address communication capability
		{laddr: net.TCPAddr{IP: net.IPv4(127, 0, 0, 1)}, value: 0},
	}

	for i := range probes {
		s, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_STREAM, syscall.IPPROTO_TCP)
		if err != nil {
			continue
		}
		defer closesocket(s)
		syscall.SetsockoptInt(s, syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, probes[i].value)
		sa, err := sockaddrTCP(&probes[i].laddr, syscall.AF_INET6)
		if err != nil {
			continue
		}
		if err := syscall.Bind(s, sa); err != nil {
			continue
		}
		probes[i].ok = true
	}

	return probes[0].ok, probes[1].ok
}

func (nlSock *NLSocket) Init() error {
	//16 - NETLINK_GENERIC
	sd, err := syscall.Socket(syscall.AF_NETLINK, syscall.SOCK_DGRAM, NETLINK_GENERIC)
	if err != nil {
		return fmt.Errorf("cant create netlink socket %v\n", err)
	}
	pid := uint32(syscall.Getpid())
	sa := &syscall.SockaddrNetlink{
		Pid:    pid,
		Groups: 0,
		Family: syscall.AF_NETLINK}
	if err = syscall.Bind(sd, sa); err != nil {
		return fmt.Errorf("cant bind to netlink socket: %v\n", err)
	}
	nlSock.Lock = new(sync.Mutex)
	nlSock.Sd = sd
	nlSock.Seq = 0
	nlSock.PortID = pid
	for k, v := range LookupOnStartup {
		familyId, err := nlSock.ResolveFamily(NulStringType(k))
		if err != nil {
			return err
		}
		CreateMsgType(v, uint16(*familyId))
		MT2Family[k] = uint16(*familyId)
	}
	return nil
}

func main() {
	acceptingFd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM, 0)
	check(err)

	addr := &syscall.SockaddrInet4{Port: 3000, Addr: [4]byte{0, 0, 0, 0}}
	err = syscall.Bind(acceptingFd, addr)
	check(err)

	err = syscall.Listen(acceptingFd, 100)
	check(err)

	for {
		connectionFd, _, err := syscall.Accept(acceptingFd)
		check(err)
		fmt.Println("Accepted new connectrion")

		data := make([]byte, 1024)
		_, err = syscall.Read(connectionFd, data)
		check(err)
		fmt.Printf("Received: %s\n", string(data))

		_, err = syscall.Write(connectionFd, data)
		check(err)

		err = syscall.Close(connectionFd)
		check(err)
	}
}

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

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

	if fd, err = syscall.Socket(soType, syscall.SOCK_DGRAM, syscall.IPPROTO_UDP); err != nil {
		return nil, err
	}

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

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

	// File Name get be nil
	file = os.NewFile(uintptr(fd), filePrefix+strconv.Itoa(os.Getpid()))
	if l, err = net.FilePacketConn(file); err != nil {
		return nil, err
	}

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

	return l, err
}

func (fd *netFD) dial(laddr, raddr sockaddr, deadline time.Time, toAddr func(syscall.Sockaddr) Addr) error {
	var err error
	var lsa syscall.Sockaddr
	if laddr != nil {
		if lsa, err = laddr.sockaddr(fd.family); err != nil {
			return err
		} else if lsa != nil {
			if err := syscall.Bind(fd.sysfd, lsa); err != nil {
				return os.NewSyscallError("bind", err)
			}
		}
	}
	var rsa syscall.Sockaddr
	if raddr != nil {
		if rsa, err = raddr.sockaddr(fd.family); err != nil {
			return err
		}
		if err := fd.connect(lsa, rsa, deadline); err != nil {
			return err
		}
		fd.isConnected = true
	} else {
		if err := fd.init(); err != nil {
			return err
		}
	}
	lsa, _ = syscall.Getsockname(fd.sysfd)
	if rsa, _ = syscall.Getpeername(fd.sysfd); rsa != nil {
		fd.setAddr(toAddr(lsa), toAddr(rsa))
	} else {
		fd.setAddr(toAddr(lsa), raddr)
	}
	return nil
}

func (fd *netFD) dial(ctx context.Context, laddr, raddr sockaddr) error {
	var err error
	var lsa syscall.Sockaddr
	if laddr != nil {
		if lsa, err = laddr.sockaddr(fd.family); err != nil {
			return err
		} else if lsa != nil {
			if err := syscall.Bind(fd.sysfd, lsa); err != nil {
				return os.NewSyscallError("bind", err)
			}
		}
	}
	var rsa syscall.Sockaddr
	if raddr != nil {
		if rsa, err = raddr.sockaddr(fd.family); err != nil {
			return err
		}
		if err := fd.connect(ctx, lsa, rsa); err != nil {
			return err
		}
		fd.isConnected = true
	} else {
		if err := fd.init(); err != nil {
			return err
		}
	}
	lsa, _ = syscall.Getsockname(fd.sysfd)
	if rsa, _ = syscall.Getpeername(fd.sysfd); rsa != nil {
		fd.setAddr(fd.addrFunc()(lsa), fd.addrFunc()(rsa))
	} else {
		fd.setAddr(fd.addrFunc()(lsa), raddr)
	}
	return nil
}

// Bind our netlink socket and
// send a listen control message to the connector driver.
func (listener *netlinkListener) bind() error {
	sock, err := syscall.Socket(
		syscall.AF_NETLINK,
		syscall.SOCK_DGRAM,
		syscall.NETLINK_CONNECTOR)

	if err != nil {
		return err
	}

	listener.sock = sock
	listener.addr = &syscall.SockaddrNetlink{
		Family: syscall.AF_NETLINK,
		Groups: _CN_IDX_PROC,
		Pid:    uint32(os.Getpid()),
	}

	err = syscall.Bind(listener.sock, listener.addr)

	if err != nil {
		return err
	}

	return listener.send(_PROC_CN_MCAST_LISTEN)
}

func (fd *netFD) connect(la, ra syscall.Sockaddr) error {
	// Do not need to call fd.writeLock here,
	// because fd is not yet accessible to user,
	// so no concurrent operations are possible.
	if !canUseConnectEx(fd.net) {
		return syscall.Connect(fd.sysfd, ra)
	}
	// ConnectEx windows API requires an unconnected, previously bound socket.
	if la == nil {
		switch ra.(type) {
		case *syscall.SockaddrInet4:
			la = &syscall.SockaddrInet4{}
		case *syscall.SockaddrInet6:
			la = &syscall.SockaddrInet6{}
		default:
			panic("unexpected type in connect")
		}
		if err := syscall.Bind(fd.sysfd, la); err != nil {
			return err
		}
	}
	// Call ConnectEx API.
	o := &fd.wop
	o.sa = ra
	_, err := wsrv.ExecIO(o, "ConnectEx", func(o *operation) error {
		return syscall.ConnectEx(o.fd.sysfd, o.sa, nil, 0, nil, &o.o)
	})
	if err != nil {
		return err
	}
	// Refresh socket properties.
	return syscall.Setsockopt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_UPDATE_CONNECT_CONTEXT, (*byte)(unsafe.Pointer(&fd.sysfd)), int32(unsafe.Sizeof(fd.sysfd)))
}

func (io *NetIOManager) ProxyNetListen(sa syscall.Sockaddr) error {
	serverfd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM,
		syscall.IPPROTO_TCP)
	if err != nil {
		goto Error
	}

	err = syscall.Bind(serverfd, sa)
	if err != nil {
		goto Cleanup
	}

	err = syscall.Listen(serverfd, io.max_backlog)
	if err != nil {
		goto Cleanup
	}

	err = syscall.EpollCtl(io.epoll_fd, syscall.EPOLL_CTL_ADD, serverfd,
		&syscall.EpollEvent{Events: syscall.EPOLLIN, Fd: int32(serverfd)})
	if err != nil {
		goto Cleanup
	}

	io.proxy_server_fd = serverfd
	return nil

Cleanup:
	syscall.Close(serverfd)
Error:
	return err
}

func (fd *netFD) connect(ra syscall.Sockaddr) error {
	if !canUseConnectEx(fd.net) {
		return syscall.Connect(fd.sysfd, ra)
	}
	// ConnectEx windows API requires an unconnected, previously bound socket.
	var la syscall.Sockaddr
	switch ra.(type) {
	case *syscall.SockaddrInet4:
		la = &syscall.SockaddrInet4{}
	case *syscall.SockaddrInet6:
		la = &syscall.SockaddrInet6{}
	default:
		panic("unexpected type in connect")
	}
	if err := syscall.Bind(fd.sysfd, la); err != nil {
		return err
	}
	// Call ConnectEx API.
	var o connectOp
	o.Init(fd, 'w')
	o.ra = ra
	_, err := iosrv.ExecIO(&o, fd.wdeadline.value())
	if err != nil {
		return err
	}
	// Refresh socket properties.
	return syscall.Setsockopt(fd.sysfd, syscall.SOL_SOCKET, syscall.SO_UPDATE_CONNECT_CONTEXT, (*byte)(unsafe.Pointer(&fd.sysfd)), int32(unsafe.Sizeof(fd.sysfd)))
}