{"", "::1", &IPAddr{IP: ParseIP("::1")}, nil},           // Go 1.0 behavior

	{"ip4:icmp", "", &IPAddr{}, nil},

	{"l2tp", "127.0.0.1", nil, UnknownNetworkError("l2tp")},
	{"l2tp:gre", "127.0.0.1", nil, UnknownNetworkError("l2tp:gre")},
	{"tcp", "1.2.3.4:123", nil, UnknownNetworkError("tcp")},

	{"ip4", "2001:db8::1", nil, &AddrError{Err: errNoSuitableAddress.Error(), Addr: "2001:db8::1"}},

	network, proto, err := parseNetwork(ctx, sd.network, true)
	if err != nil {
		return nil, err
	}
	switch network {
	case "ip", "ip4", "ip6":
	default:
		return nil, UnknownNetworkError(sd.network)
	}
	ctrlCtxFn := sd.Dialer.ControlContext
	if ctrlCtxFn == nil && sd.Dialer.Control != nil {
		ctrlCtxFn = func(ctx context.Context, network, address string, c syscall.RawConn) error {

// parameters.
func ResolveUnixAddr(network, address string) (*UnixAddr, error) {
	switch network {
	case "unix", "unixgram", "unixpacket":
		return &UnixAddr{Name: address, Net: network}, nil
	default:
		return nil, UnknownNetworkError(network)
	}
}

// UnixConn is an implementation of the [Conn] interface for connections
// to Unix domain sockets.
type UnixConn struct {
	conn
}

// SyscallConn returns a raw network connection.

	if err != nil {
		return 0, err
	}
	if len(lines) == 0 {
		return 0, UnknownNetworkError(name)
	}
	f := getFields(lines[0])
	if len(f) < 2 {
		return 0, UnknownNetworkError(name)
	}
	s := f[1]
	if n, _, ok := dtoi(s[bytealg.IndexByteString(s, '=')+1:]); ok {
		return n, nil
	}
	return 0, UnknownNetworkError(name)
}

func ResolveUDPAddr(network, address string) (*UDPAddr, error) {
	switch network {
	case "udp", "udp4", "udp6":
	case "": // a hint wildcard for Go 1.0 undocumented behavior
		network = "udp"
	default:
		return nil, UnknownNetworkError(network)
	}
	addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
	if err != nil {
		return nil, err
	}
	return addrs.forResolve(network, address).(*UDPAddr), nil
}

			ip = ip[:IPv4len]
		}
	}
	switch net {
	case "tcp", "tcp4", "tcp6":
		addr = &TCPAddr{IP: ip, Port: port}
	case "udp", "udp4", "udp6":
		addr = &UDPAddr{IP: ip, Port: port}
	default:
		return nil, UnknownNetworkError(net)
	}
	return addr, nil
}

func startPlan9(ctx context.Context, net string, addr Addr) (ctl *os.File, dest, proto, name string, err error) {
	var (
		ip   IP
		port int
	)

		if laddr != nil && len(laddr.IP) != 0 && laddr.IP.To4() == nil {
			return nil, &AddrError{Err: "non-IPv4 local address", Addr: laddr.String()}
		}
	case "tcp", "tcp6":
	default:
		return nil, UnknownNetworkError(sd.network)
	}
	if raddr == nil {
		return nil, errMissingAddress
	}
	fd, err := dialPlan9(ctx, sd.network, laddr, raddr)
	if err != nil {
		return nil, err
	}

func ResolveTCPAddr(network, address string) (*TCPAddr, error) {
	switch network {
	case "tcp", "tcp4", "tcp6":
	case "": // a hint wildcard for Go 1.0 undocumented behavior
		network = "tcp"
	default:
		return nil, UnknownNetworkError(network)
	}
	addrs, err := DefaultResolver.internetAddrList(context.Background(), network, address)
	if err != nil {
		return nil, err
	}
	return addrs.forResolve(network, address).(*TCPAddr), nil
}

		}
	case "udp6":
		fd := ln.(*UDPConn).fd
		if fd.family != syscall.AF_INET6 {
			return fmt.Errorf("%v got %v; want %v", fd.laddr, fd.family, syscall.AF_INET6)
		}
	default:
		return UnknownNetworkError(network)
	}
	return nil
}

func checkSecondListener(network, address string, err error) error {
	switch network {
	case "tcp", "tcp4", "tcp6":
		if err == nil {

func (e *AddrError) Timeout() bool   { return false }
func (e *AddrError) Temporary() bool { return false }

type UnknownNetworkError string

func (e UnknownNetworkError) Error() string   { return "unknown network " + string(e) }
func (e UnknownNetworkError) Timeout() bool   { return false }
func (e UnknownNetworkError) Temporary() bool { return false }

type InvalidAddrError string