case *syscall.SockaddrInet6:
		return &UDPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneCache.name(int(sa.ZoneId))}
	}
	return nil
}

func (a *UDPAddr) family() int {
	if a == nil || len(a.IP) <= IPv4len {
		return syscall.AF_INET
	}
	if a.IP.To4() != nil {
		return syscall.AF_INET
	}
	return syscall.AF_INET6
}

func (a *UDPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {

	case *syscall.SockaddrInet6:
		return &TCPAddr{IP: sa.Addr[0:], Port: sa.Port, Zone: zoneCache.name(int(sa.ZoneId))}
	}
	return nil
}

func (a *TCPAddr) family() int {
	if a == nil || len(a.IP) <= IPv4len {
		return syscall.AF_INET
	}
	if a.IP.To4() != nil {
		return syscall.AF_INET
	}
	return syscall.AF_INET6
}

func (a *TCPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {

	if err != nil {
		return
	}
	ip, port, err := parsePlan9Addr(string(buf[:n]))
	if err != nil {
		return
	}
	switch net {
	case "tcp4", "udp4":
		if ip.Equal(IPv6zero) {
			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)

		}
	}
}

var sink string

func BenchmarkIPString(b *testing.B) {
	testHookUninstaller.Do(uninstallTestHooks)

	b.Run("IPv4", func(b *testing.B) {
		benchmarkIPString(b, IPv4len)
	})

	b.Run("IPv6", func(b *testing.B) {
		benchmarkIPString(b, IPv6len)
	})
}

func benchmarkIPString(b *testing.B, size int) {
	b.ReportAllocs()
	b.ResetTimer()

	if str == "" {
		return nil, fmt.Errorf("input is nil")
	}
	bytes, err := hex.DecodeString(str)
	if err != nil {
		return nil, err
	}
	if family == familyIPv4 {
		if len(bytes) != net.IPv4len {
			return nil, fmt.Errorf("invalid IPv4 address in route")
		}
		return net.IP([]byte{bytes[3], bytes[2], bytes[1], bytes[0]}), nil
	}
	// Must be IPv6
	if len(bytes) != net.IPv6len {

						}, c.PermittedURIDomains, c.ExcludedURIDomains); err != nil {
						return err
					}

				case nameTypeIP:
					ip := net.IP(data)
					if l := len(ip); l != net.IPv4len && l != net.IPv6len {
						return fmt.Errorf("x509: internal error: IP SAN %x failed to parse", data)
					}

					if err := c.checkNameConstraints(&comparisonCount, maxConstraintComparisons, "IP address", ip.String(), ip,

					return fmt.Errorf("x509: cannot parse URI %q: invalid domain", uriStr)
				}
			}
			uris = append(uris, uri)
		case nameTypeIP:
			switch len(data) {
			case net.IPv4len, net.IPv6len:
				ipAddresses = append(ipAddresses, data)
			default:
				return errors.New("x509: cannot parse IP address of length " + strconv.Itoa(len(data)))
			}
		}

		return nil
	})

			t.Errorf("socks5 proxy second read: got %v, want %v", buf[:3], want)
			return
		}
		var ipLen int
		switch buf[3] {
		case 1:
			ipLen = net.IPv4len
		case 4:
			ipLen = net.IPv6len
		default:
			t.Errorf("socks5 proxy second read: unexpected address type %v", buf[4])
			return
		}
		if _, err := io.ReadFull(s, buf[4:ipLen+6]); err != nil {

		{"IPNet.IP", Field, 0},
		{"IPNet.Mask", Field, 0},
		{"IPv4", Func, 0},
		{"IPv4Mask", Func, 0},
		{"IPv4allrouter", Var, 0},
		{"IPv4allsys", Var, 0},
		{"IPv4bcast", Var, 0},
		{"IPv4len", Const, 0},
		{"IPv4zero", Var, 0},
		{"IPv6interfacelocalallnodes", Var, 0},
		{"IPv6len", Const, 0},
		{"IPv6linklocalallnodes", Var, 0},
		{"IPv6linklocalallrouters", Var, 0},
		{"IPv6loopback", Var, 0},

pkg net, const FlagBroadcast Flags
pkg net, const FlagLoopback Flags
pkg net, const FlagMulticast Flags
pkg net, const FlagPointToPoint Flags
pkg net, const FlagUp Flags
pkg net, const IPv4len ideal-int
pkg net, const IPv6len ideal-int
pkg net, func CIDRMask(int, int) IPMask
pkg net, func Dial(string, string) (Conn, error)
pkg net, func DialIP(string, *IPAddr, *IPAddr) (*IPConn, error)