const DNS1123SubdomainMaxLength int = 253

var dns1123SubdomainRegexp = regexp.MustCompile("^" + dns1123SubdomainFmt + "$")

// IsDNS1123Subdomain tests for a string that conforms to the definition of a
// subdomain in DNS (RFC 1123).
func IsDNS1123Subdomain(value string) []string {
	var errs []string
	if len(value) > DNS1123SubdomainMaxLength {
		errs = append(errs, MaxLenError(DNS1123SubdomainMaxLength))
	}

					allErrs = append(allErrs, field.Invalid(fldPath.Index(tlsIndex).Child("hosts").Index(i), host, msg))
				}
				continue
			}
			for _, msg := range validation.IsDNS1123Subdomain(host) {
				allErrs = append(allErrs, field.Invalid(fldPath.Index(tlsIndex).Child("hosts").Index(i), host, msg))
			}
		}

		if !opts.AllowInvalidSecretName {

	} else {
		nameFldPath := fldPath.Child("name")
		for _, err := range validation.IsDNS1123Subdomain(nro.Name) {
			allErrs = append(allErrs, field.Invalid(nameFldPath, nro.Name, err))
		}
	}
	allErrs = append(allErrs, ValidateSocketPath(nro.CRISocket, fldPath.Child("criSocket"))...)

	if ref == nil {
		return allErrs
	}

	// group is required but the Core group is the empty value, so it can not be enforced.
	if ref.APIGroup != "" {
		for _, msg := range utilvalidation.IsDNS1123Subdomain(ref.APIGroup) {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("apiGroup"), ref.APIGroup, msg))
		}
	}

	if ref.Kind == "" {
		allErrs = append(allErrs, field.Required(fldPath.Child("kind"), ""))

		"0.1", "01.1", "012.1", "1a.1", "1-a.1", "1--a--b--2.1",
		"a.b.c.d.e", "aa.bb.cc.dd.ee", "1.2.3.4.5", "11.22.33.44.55",
		strings.Repeat("a", 253),
	}
	for _, val := range goodValues {
		if msgs := IsDNS1123Subdomain(val); len(msgs) != 0 {
			t.Errorf("expected true for '%s': %v", val, msgs)
		}
	}

	badValues := []string{
		"", "A", "ABC", "aBc", "A1", "A-1", "1-A",
		"-", "a-", "-a", "1-", "-1",

			mcpVersion, cfg.KubernetesVersion)
	}
	return nil
}

// LowercaseSANs can be used to force all SANs to be lowercase so it passes IsDNS1123Subdomain
func LowercaseSANs(sans []string) {
	for i, san := range sans {
		lowercase := strings.ToLower(san)
		if lowercase != san {
			klog.V(1).Infof("lowercasing SAN %q to %q", san, lowercase)
			sans[i] = lowercase

	for _, altname := range SANs {
		if ip := netutils.ParseIPSloppy(altname); ip != nil {
			altNames.IPs = append(altNames.IPs, ip)
		} else if len(validation.IsDNS1123Subdomain(altname)) == 0 {
			altNames.DNSNames = append(altNames.DNSNames, altname)
		} else if len(validation.IsWildcardDNS1123Subdomain(altname)) == 0 {
			altNames.DNSNames = append(altNames.DNSNames, altname)
		} else {

		} else if seenAuthorizerNames.Has(a.Name) {
			allErrs = append(allErrs, field.Duplicate(fldPath.Child("name"), a.Name))
		} else if errs := utilvalidation.IsDNS1123Subdomain(a.Name); len(errs) != 0 {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("name"), a.Name, fmt.Sprintf("authorizer name is invalid: %s", strings.Join(errs, ", "))))
		}
		seenAuthorizerNames.Insert(a.Name)