}
	cases := []struct {
		name string
		cidr string
		v4   NetworkRange
		v6   NetworkRange
	}{
		{
			name: "wildcard",
			cidr: "*",
			v4:   NetworkRange{IsWildcard: true},
			v6:   NetworkRange{IsWildcard: true},
		},
		{
			name: "v4 only",
			cidr: "10.0.0.0/8,172.16.0.0/16",
			v4:   NetworkRange{CIDRs: mkIPList("10.0.0.0/8", "172.16.0.0/16")},
		},
		{
			name: "v6 only",

	case "unixpacket":
		sotype = syscall.SOCK_SEQPACKET
	default:
		return nil, UnknownNetworkError(net)
	}

	switch mode {
	case "dial":
		if laddr != nil && laddr.isWildcard() {
			laddr = nil
		}
		if raddr != nil && raddr.isWildcard() {
			raddr = nil
		}
		if raddr == nil && (sotype != syscall.SOCK_DGRAM || laddr == nil) {
			return nil, errMissingAddress
		}
	case "listen":
	default:

	switch network[len(network)-1] {
	case '4':
		return syscall.AF_INET, false
	case '6':
		return syscall.AF_INET6, true
	}

	if mode == "listen" && (laddr == nil || laddr.isWildcard()) {
		if supportsIPv4map() || !supportsIPv4() {
			return syscall.AF_INET6, false
		}
		if laddr == nil {
			return syscall.AF_INET, false
		}
		return laddr.family(), false
	}