testCases := []struct {
		tcase    string
		addr     []net.Addr
		family   AddressFamily
		expected net.IP
	}{
		{"no ipv4", []net.Addr{addrStruct{val: "2001::5/64"}}, familyIPv4, nil},
		{"no ipv6", []net.Addr{addrStruct{val: "10.128.0.4/32"}}, familyIPv6, nil},
		{"invalidV4CIDR", []net.Addr{addrStruct{val: "10.20.30.40.50/24"}}, familyIPv4, nil},

				{
					itf:   net.Interface{Index: 0, MTU: 0, Name: "eth0", HardwareAddr: nil, Flags: 0},
					addrs: []net.Addr{&net.IPNet{IP: netutils.ParseIPSloppy("10.20.30.51"), Mask: net.CIDRMask(24, 32)}},
				},
				{
					itf:   net.Interface{Index: 2, MTU: 0, Name: "eth1", HardwareAddr: nil, Flags: 0},
					addrs: []net.Addr{&net.IPNet{IP: netutils.ParseIPSloppy("100.200.201.1"), Mask: net.CIDRMask(24, 32)}},
				},
			},

	if len(b) < l {
		return 0, nil, errInvalidAddr
	}
	data := b[4:]
	var name string
	var addr []byte
	if nlen > 0 {
		name = string(data[:nlen])
		data = data[nlen:]
	}
	if alen > 0 {
		addr = data[:alen]
		data = data[alen:]
	}
	return l, &LinkAddr{Name: name, Addr: addr}, nil
}

// An Inet4Addr represents an internet address for IPv4.
type Inet4Addr struct {

	for _, tt := range resolveUDPAddrTests {
		addr, err := ResolveUDPAddr(tt.network, tt.litAddrOrName)
		if !reflect.DeepEqual(addr, tt.addr) || !reflect.DeepEqual(err, tt.err) {
			t.Errorf("ResolveUDPAddr(%q, %q) = %#v, %v, want %#v, %v", tt.network, tt.litAddrOrName, addr, err, tt.addr, tt.err)
			continue
		}
		if err == nil {
			addr2, err := ResolveUDPAddr(addr.Network(), addr.String())

	switch {
	case ctx.IsSet("config-dir"):
		ctxt.ConfigDir = ctx.String("config-dir")
		ctxt.configDirSet = true
	case ctx.GlobalIsSet("config-dir"):
		ctxt.ConfigDir = ctx.GlobalString("config-dir")
		ctxt.configDirSet = true
	}

	switch {
	case ctx.IsSet("certs-dir"):
		ctxt.CertsDir = ctx.String("certs-dir")
		ctxt.certsDirSet = true
	case ctx.GlobalIsSet("certs-dir"):

		}
	}

	for i, tt := range tests {
		d := &Dialer{LocalAddr: tt.laddr}
		var addr string
		ip := ParseIP(tt.raddr)
		if ip.To4() != nil {
			addr = lss[0].Listener.Addr().String()
		}
		if ip.To16() != nil && ip.To4() == nil {
			addr = lss[1].Listener.Addr().String()
		}
		c, err := d.Dial(tt.network, addr)
		if err == nil && tt.error != nil || err != nil && tt.error == nil {

		link := &node[T]{
			prefix: ancestor,
		}
		pos := parent.prefix.Bits() + 1
		parent.child[getBitFromAddr(ancestor.Addr(), pos)] = link
		// ancestor -> children
		pos = ancestor.Bits() + 1
		idxChild := getBitFromAddr(prefix.Addr(), pos)
		idxN := getBitFromAddr(n.prefix.Addr(), pos)
		if idxChild == idxN {
			panic(fmt.Sprintf("wrong ancestor %s: child %s N %s", ancestor.String(), prefix.String(), n.prefix.String()))

		if len(f) < 2 {
			continue
		}
		addr := f[1]
		if i := bytealg.IndexByteString(addr, '!'); i >= 0 {
			addr = addr[:i] // remove port
		}
		if ParseIP(addr) == nil {
			continue
		}
		// only return unique addresses
		for _, a := range addrs {
			if a == addr {
				continue loop
			}
		}
		addrs = append(addrs, addr)
	}
	return
}

	for _, tt := range resolveTCPAddrTests {
		addr, err := ResolveTCPAddr(tt.network, tt.litAddrOrName)
		if !reflect.DeepEqual(addr, tt.addr) || !reflect.DeepEqual(err, tt.err) {
			t.Errorf("ResolveTCPAddr(%q, %q) = %#v, %v, want %#v, %v", tt.network, tt.litAddrOrName, addr, err, tt.addr, tt.err)
			continue
		}
		if err == nil {
			addr2, err := ResolveTCPAddr(addr.Network(), addr.String())

	}
	naddrs := addrs[:0]
	for _, addr := range addrs {
		if addr.Network() != hint.Network() {
			return nil, &AddrError{Err: "mismatched local address type", Addr: hint.String()}
		}
		switch addr := addr.(type) {
		case *TCPAddr:
			if !wildcard && !addr.isWildcard() && !addr.IP.matchAddrFamily(tcp.IP) {
				continue
			}
			naddrs = append(naddrs, addr)
		case *UDPAddr: