//   The IANA has assigned the FC00::/7 prefix to "Unique Local Unicast".
	return len(ip) == IPv6len && ip[0]&0xfe == 0xfc
}

// IsMulticast reports whether ip is a multicast address.
func (ip IP) IsMulticast() bool {
	if ip4 := ip.To4(); ip4 != nil {
		return ip4[0]&0xf0 == 0xe0
	}
	return len(ip) == IPv6len && ip[0] == 0xff
}

// IsInterfaceLocalMulticast reports whether ip is

			ipIntLeft := binary.BigEndian.Uint64(cidr.IP[:net.IPv6len/2]) | (^binary.BigEndian.Uint64(cidr.Mask[:net.IPv6len/2]))
			ipIntRight := binary.BigEndian.Uint64(cidr.IP[net.IPv6len/2:]) | (^binary.BigEndian.Uint64(cidr.Mask[net.IPv6len/2:]))
			binary.BigEndian.PutUint64(ip[:net.IPv6len/2], ipIntLeft)
			binary.BigEndian.PutUint64(ip[net.IPv6len/2:], ipIntRight)
		}
		end, err = s.getIndexForIP(net.IP(ip).Mask(s.nodeMask))

				case *syscall.SockaddrInet6:
					ifa := &IPNet{IP: make(IP, IPv6len), Mask: CIDRMask(int(puni.OnLinkPrefixLength), 8*IPv6len)}
					copy(ifa.IP, sa.Addr[:])
					ifat = append(ifat, ifa)
				}
			}
			for pany := aa.FirstAnycastAddress; pany != nil; pany = pany.Next {

		case syscall.AF_INET:
			return &IPNet{IP: IPv4(a.Value[0], a.Value[1], a.Value[2], a.Value[3]), Mask: CIDRMask(int(ifam.Prefixlen), 8*IPv4len)}
		case syscall.AF_INET6:
			ifa := &IPNet{IP: make(IP, IPv6len), Mask: CIDRMask(int(ifam.Prefixlen), 8*IPv6len)}
			copy(ifa.IP, a.Value[:])
			return ifa
		}
	}
	return nil
}

// interfaceMulticastAddrTable returns addresses for a specific
// interface.

				}
				stats.ipv4++
			}
			if ifa.IP.To16() != nil && ifa.IP.To4() == nil {
				if 0 >= prefixLen || prefixLen > 8*IPv6len || maxPrefixLen != 8*IPv6len {
					return nil, fmt.Errorf("unexpected prefix length: %d/%d for %#v", prefixLen, maxPrefixLen, ifa)
				}
				if ifa.IP.IsLoopback() && prefixLen != 8*IPv6len { // see RFC 4291
					return nil, fmt.Errorf("unexpected prefix length: %d/%d for %#v", prefixLen, maxPrefixLen, ifa)
				}

		switch a := a.(type) {
		case *lif.Inet4Addr:
			ip = IPv4(a.IP[0], a.IP[1], a.IP[2], a.IP[3])
			mask = CIDRMask(a.PrefixLen, 8*IPv4len)
		case *lif.Inet6Addr:
			ip = make(IP, IPv6len)
			copy(ip, a.IP[:])
			mask = CIDRMask(a.PrefixLen, 8*IPv6len)
		}
		ifat = append(ifat, &IPNet{IP: ip, Mask: mask})
	}
	return ifat, nil
}

// interfaceMulticastAddrTable returns addresses for a specific
// interface.

				continue
			}
			var ip IP
			switch sa := m.Addrs[syscall.RTAX_IFA].(type) {
			case *route.Inet4Addr:
				ip = IPv4(sa.IP[0], sa.IP[1], sa.IP[2], sa.IP[3])
			case *route.Inet6Addr:
				ip = make(IP, IPv6len)
				copy(ip, sa.IP[:])
			}
			if ip != nil {
				ifmat = append(ifmat, &IPAddr{IP: ip})
			}
		}
	}
	return ifmat, nil

					case syscall.AF_INET6:
						ipsa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(iprsa))
						nmsa := (*syscall.RawSockaddrInet6)(unsafe.Pointer(nmrsa))
						ip = make(IP, IPv6len)
						copy(ip, ipsa.Addr[:])
						mask = make(IPMask, IPv6len)
						copy(mask, nmsa.Addr[:])
					}
					ifa := &IPNet{IP: ip, Mask: mask}
					ifat = append(ifat, ifa)
				}
			}
		}
		tab = tab[ifm.Msglen:]
	}

				continue NextVar
			}
		}
		out = append(out, inkv)
	}
	return out
}

const (
	IPv4len = 4
	IPv6len = 16
)

var v4InV6Prefix = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff}

func IPv4(a, b, c, d byte) IP {
	p := make(IP, IPv6len) // ERROR "make\(IP, 16\) escapes to heap"
	copy(p, v4InV6Prefix)
	p[12] = a
	p[13] = b
	p[14] = c
	p[15] = d
	return p
}

			case *route.Inet6Addr:
				mask = make(IPMask, IPv6len)
				copy(mask, sa.IP[:])
			}
			var ip IP
			switch sa := m.Addrs[syscall.RTAX_IFA].(type) {
			case *route.Inet4Addr:
				ip = IPv4(sa.IP[0], sa.IP[1], sa.IP[2], sa.IP[3])
			case *route.Inet6Addr:
				ip = make(IP, IPv6len)
				copy(ip, sa.IP[:])
			}