Feature/dns protocol (#543)

Added DNS update protocol message

Added sync to clients

Update nameserver API with new fields

Added default NS groups

Added new dns-name flag for the management service append to peer DNS label

dns/dns.go

@@ -5,6 +5,9 @@ package dns
 import (
 	"fmt"
 	"github.com/miekg/dns"
+	"golang.org/x/net/idna"
+	"regexp"
+	"strings"
 )
 
 const (
@@ -16,12 +19,14 @@ const (
 	DefaultClass = "IN"
 )
 
-// Update represents a dns update that is exchanged between management and peers
-type Update struct {
+const invalidHostLabel = "[^a-zA-Z0-9-]+"
+
+// Config represents a dns configuration that is exchanged between management and peers
+type Config struct {
 	// ServiceEnable indicates if the service should be enabled
 	ServiceEnable bool
 	// NameServerGroups contains a list of nameserver group
-	NameServerGroups []NameServerGroup
+	NameServerGroups []*NameServerGroup
 	// CustomZones contains a list of custom zone
 	CustomZones []CustomZone
 }
@@ -54,3 +59,26 @@ func (s SimpleRecord) String() string {
 	fqdn := dns.Fqdn(s.Name)
 	return fmt.Sprintf("%s %d %s %s %s", fqdn, s.TTL, s.Class, dns.Type(s.Type).String(), s.RData)
 }
+
+// GetParsedDomainLabel returns a domain label with max 59 characters,
+// parsed for old Hosts.txt requirements, and converted to ASCII and lowercase
+func GetParsedDomainLabel(name string) (string, error) {
+	labels := dns.SplitDomainName(name)
+	if len(labels) == 0 {
+		return "", fmt.Errorf("got empty label list for name \"%s\"", name)
+	}
+	rawLabel := labels[0]
+	ascii, err := idna.Punycode.ToASCII(rawLabel)
+	if err != nil {
+		return "", fmt.Errorf("unable to convert host lavel to ASCII, error: %v", err)
+	}
+
+	invalidHostMatcher := regexp.MustCompile(invalidHostLabel)
+
+	validHost := strings.ToLower(invalidHostMatcher.ReplaceAllString(ascii, "-"))
+	if len(validHost) > 58 {
+		validHost = validHost[:59]
+	}
+
+	return validHost, nil
+}