// address in /proc/net/igmp in native
				// endianness.
				for i := 0; i+1 < len(f[0]); i += 2 {
					b[i/2], _ = xtoi2(f[0][i:i+2], 0)
				}
				i := *(*uint32)(unsafe.Pointer(&b[:4][0]))
				ifma := &IPAddr{IP: IPv4(byte(i>>24), byte(i>>16), byte(i>>8), byte(i))}
				ifmat = append(ifmat, ifma)
			}
		}
	}
	return ifmat
}

func parseProcNetIGMP6(path string, ifi *Interface) []Addr {

		for _, a := range addrs {
			if a == addr {
				continue loop
			}
		}
		addrs = append(addrs, addr)
	}
	return
}

func (r *Resolver) lookupIP(ctx context.Context, network, host string) (addrs []IPAddr, err error) {
	if order, conf := systemConf().hostLookupOrder(r, host); order != hostLookupCgo {
		return r.goLookupIP(ctx, network, host, order, conf)
	}

	lits, err := r.lookupHost(ctx, host)
	if err != nil {

		return addrs, err
	}
	var (
		tcp      *TCPAddr
		udp      *UDPAddr
		ip       *IPAddr
		wildcard bool
	)
	switch hint := hint.(type) {
	case *TCPAddr:
		tcp = hint
		wildcard = tcp.isWildcard()
	case *UDPAddr:
		udp = hint
		wildcard = udp.isWildcard()
	case *IPAddr:
		ip = hint
		wildcard = ip.isWildcard()
	}
	naddrs := addrs[:0]
	for _, addr := range addrs {

// cidr('192.168.1.0/24').containsCIDR('192.168.2.0/24') // returns false
// cidr('192.168.0.1/24').ip() // returns ipAddr('192.168.0.1')
// cidr('192.168.0.1/24').ip().family() // returns '4'
// cidr('::1/128').ip() // returns ipAddr('::1')
// cidr('::1/128').ip().family() // returns '6'
// cidr('192.168.0.0/24').masked() // returns cidr('192.168.0.0/24')

				}
				if ifa.IP.IsLoopback() && prefixLen != 8*IPv6len { // see RFC 4291
					return nil, fmt.Errorf("unexpected prefix length: %d/%d for %#v", prefixLen, maxPrefixLen, ifa)
				}
				stats.ipv6++
			}
		case *IPAddr:
			if ifa == nil || ifa.IP == nil || ifa.IP.IsMulticast() {
				return nil, fmt.Errorf("unexpected value: %#v", ifa)
			}
			if len(ifa.IP) != IPv6len {

		v.Op = OpMIPS64ADDF
		return true
	case OpAdd64:
		v.Op = OpMIPS64ADDV
		return true
	case OpAdd64F:
		v.Op = OpMIPS64ADDD
		return true
	case OpAdd8:
		v.Op = OpMIPS64ADDV
		return true
	case OpAddPtr:
		v.Op = OpMIPS64ADDV
		return true
	case OpAddr:
		return rewriteValueMIPS64_OpAddr(v)
	case OpAnd16:
		v.Op = OpMIPS64AND
		return true
	case OpAnd32:
		v.Op = OpMIPS64AND
		return true

		v.Op = OpRISCV64FADDS
		return true
	case OpAdd64:
		v.Op = OpRISCV64ADD
		return true
	case OpAdd64F:
		v.Op = OpRISCV64FADDD
		return true
	case OpAdd8:
		v.Op = OpRISCV64ADD
		return true
	case OpAddPtr:
		v.Op = OpRISCV64ADD
		return true
	case OpAddr:
		return rewriteValueRISCV64_OpAddr(v)
	case OpAnd16:
		v.Op = OpRISCV64AND
		return true
	case OpAnd32:
		v.Op = OpRISCV64AND
		return true

	}
	var ip IP
	var wildcard bool
	switch addr := addr.(type) {
	case *TCPAddr:
		ip = addr.IP
		wildcard = addr.isWildcard()
	case *UDPAddr:
		ip = addr.IP
		wildcard = addr.isWildcard()
	case *IPAddr:
		ip = addr.IP
		wildcard = addr.isWildcard()
	}

	// Test wildcard IP addresses.
	if wildcard && !testenv.HasExternalNetwork() {
		return false
	}

	}{
		{
			"Empty",
			func(ip net.IP) bool { return false },
			nil,
			nil,
		},
		{
			"Reject IPAddr x 2",
			func(ip net.IP) bool { return false },
			[]net.Addr{
				mustParseIPAddr("8.8.8.8"),
				mustParseIPAddr("1000::"),
			},
			nil,
		},
		{
			"Accept IPAddr x 2",
			func(ip net.IP) bool { return true },
			[]net.Addr{
				mustParseIPAddr("8.8.8.8"),

func AddressSet(isValid func(ip net.IP) bool, addrs []net.Addr) sets.Set[string] {
	ips := sets.New[string]()
	for _, a := range addrs {
		var ip net.IP
		switch v := a.(type) {
		case *net.IPAddr:
			ip = v.IP
		case *net.IPNet:
			ip = v.IP
		default:
			continue
		}
		if isValid(ip) {
			ips.Insert(ip.String())
		}
	}
	return ips
}