[client] Support DNS Labels for Peer Addressing

client/cmd/login.go

@@ -85,11 +85,17 @@ var loginCmd = &cobra.Command{
 
 		client := proto.NewDaemonServiceClient(conn)
 
+		var dnsLabelsReq []string
+		if dnsLabelsValidated != nil {
+			dnsLabelsReq = dnsLabelsValidated.ToSafeStringList()
+		}
+
 		loginRequest := proto.LoginRequest{
 			SetupKey:             providedSetupKey,
 			ManagementUrl:        managementURL,
 			IsLinuxDesktopClient: isLinuxRunningDesktop(),
 			Hostname:             hostName,
+			DnsLabels:            dnsLabelsReq,
 		}
 
 		if rootCmd.PersistentFlags().Changed(preSharedKeyFlag) {

client/cmd/up.go

@@ -20,6 +20,7 @@ import (
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/proto"
 	"github.com/netbirdio/netbird/client/system"
+	"github.com/netbirdio/netbird/management/domain"
 	"github.com/netbirdio/netbird/util"
 )
 
@@ -29,9 +30,16 @@ const (
 	interfaceInputType
 )
 
+const (
+	dnsLabelsFlag = "extra-dns-labels"
+)
+
 var (
-	foregroundMode bool
-	upCmd          = &cobra.Command{
+	foregroundMode     bool
+	dnsLabels          []string
+	dnsLabelsValidated domain.List
+
+	upCmd = &cobra.Command{
 		Use:   "up",
 		Short: "install, login and start Netbird client",
 		RunE:  upFunc,
@@ -49,6 +57,14 @@ func init() {
 	upCmd.PersistentFlags().StringSliceVar(&extraIFaceBlackList, extraIFaceBlackListFlag, nil, "Extra list of default interfaces to ignore for listening")
 	upCmd.PersistentFlags().DurationVar(&dnsRouteInterval, dnsRouteIntervalFlag, time.Minute, "DNS route update interval")
 	upCmd.PersistentFlags().BoolVar(&blockLANAccess, blockLANAccessFlag, false, "Block access to local networks (LAN) when using this peer as a router or exit node")
+
+	upCmd.PersistentFlags().StringSliceVar(&dnsLabels, dnsLabelsFlag, nil,
+		`Sets DNS labels`+
+			`You can specify a comma-separated list of up to 32 labels. `+
+			`An empty string "" clears the previous configuration. `+
+			`E.g. --extra-dns-labels vpc1 or --extra-dns-labels vpc1,mgmt1 `+
+			`or --extra-dns-labels ""`,
+	)
 }
 
 func upFunc(cmd *cobra.Command, args []string) error {
@@ -67,6 +83,11 @@ func upFunc(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	dnsLabelsValidated, err = validateDnsLabels(dnsLabels)
+	if err != nil {
+		return err
+	}
+
 	ctx := internal.CtxInitState(cmd.Context())
 
 	if hostName != "" {
@@ -98,6 +119,7 @@ func runInForegroundMode(ctx context.Context, cmd *cobra.Command) error {
 		NATExternalIPs:      natExternalIPs,
 		CustomDNSAddress:    customDNSAddressConverted,
 		ExtraIFaceBlackList: extraIFaceBlackList,
+		DNSLabels:           dnsLabelsValidated,
 	}
 
 	if cmd.Flag(enableRosenpassFlag).Changed {
@@ -240,6 +262,8 @@ func runInDaemonMode(ctx context.Context, cmd *cobra.Command) error {
 		IsLinuxDesktopClient: isLinuxRunningDesktop(),
 		Hostname:             hostName,
 		ExtraIFaceBlacklist:  extraIFaceBlackList,
+		DnsLabels:            dnsLabels,
+		CleanDNSLabels:       dnsLabels != nil && len(dnsLabels) == 0,
 	}
 
 	if rootCmd.PersistentFlags().Changed(preSharedKeyFlag) {
@@ -430,6 +454,24 @@ func parseCustomDNSAddress(modified bool) ([]byte, error) {
 	return parsed, nil
 }
 
+func validateDnsLabels(labels []string) (domain.List, error) {
+	var (
+		domains domain.List
+		err     error
+	)
+
+	if len(labels) == 0 {
+		return domains, nil
+	}
+
+	domains, err = domain.ValidateDomains(labels)
+	if err != nil {
+		return nil, fmt.Errorf("failed to validate dns labels: %v", err)
+	}
+
+	return domains, nil
+}
+
 func isValidAddrPort(input string) bool {
 	if input == "" {
 		return true

client/internal/config.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"reflect"
 	"runtime"
+	"slices"
 	"strings"
 	"time"
 
@@ -20,6 +21,7 @@ import (
 	"github.com/netbirdio/netbird/client/internal/routemanager/dynamic"
 	"github.com/netbirdio/netbird/client/ssh"
 	mgm "github.com/netbirdio/netbird/management/client"
+	"github.com/netbirdio/netbird/management/domain"
 	"github.com/netbirdio/netbird/util"
 )
 
@@ -68,6 +70,8 @@ type ConfigInput struct {
 	DisableFirewall     *bool
 
 	BlockLANAccess *bool
+
+	DNSLabels domain.List
 }
 
 // Config Configuration type
@@ -93,6 +97,8 @@ type Config struct {
 
 	BlockLANAccess bool
 
+	DNSLabels domain.List
+
 	// SSHKey is a private SSH key in a PEM format
 	SSHKey string
 
@@ -489,6 +495,14 @@ func (config *Config) apply(input ConfigInput) (updated bool, err error) {
 		}
 	}
 
+	if input.DNSLabels != nil && !slices.Equal(config.DNSLabels, input.DNSLabels) {
+		log.Infof("updating DNS labels [ %s ] (old value: [ %s ])",
+			input.DNSLabels.SafeString(),
+			config.DNSLabels.SafeString())
+		config.DNSLabels = input.DNSLabels
+		updated = true
+	}
+
 	return updated, nil
 }
 

client/internal/connect.go

@@ -478,7 +478,7 @@ func loginToManagement(ctx context.Context, client mgm.Client, pubSSHKey []byte,
 		config.DisableDNS,
 		config.DisableFirewall,
 	)
-	loginResp, err := client.Login(*serverPublicKey, sysInfo, pubSSHKey)
+	loginResp, err := client.Login(*serverPublicKey, sysInfo, pubSSHKey, config.DNSLabels)
 	if err != nil {
 		return nil, err
 	}

client/internal/dns/local.go

@@ -14,7 +14,7 @@ type registrationMap map[string]struct{}
 
 type localResolver struct {
 	registeredMap registrationMap
-	records       sync.Map
+	records       sync.Map // key: string (domain_class_type), value: []dns.RR
 }
 
 func (d *localResolver) MatchSubdomains() bool {
@@ -43,11 +43,12 @@ func (d *localResolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	replyMessage := &dns.Msg{}
 	replyMessage.SetReply(r)
 	replyMessage.RecursionAvailable = true
-	replyMessage.Rcode = dns.RcodeSuccess
 
-	response := d.lookupRecord(r)
-	if response != nil {
-		replyMessage.Answer = append(replyMessage.Answer, response)
+	// lookup all records matching the question
+	records := d.lookupRecords(r)
+	if len(records) > 0 {
+		replyMessage.Rcode = dns.RcodeSuccess
+		replyMessage.Answer = append(replyMessage.Answer, records...)
 	} else {
 		replyMessage.Rcode = dns.RcodeNameError
 	}
@@ -58,37 +59,64 @@ func (d *localResolver) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	}
 }
 
-func (d *localResolver) lookupRecord(r *dns.Msg) dns.RR {
+// lookupRecords fetches *all* DNS records matching the first question in r.
+func (d *localResolver) lookupRecords(r *dns.Msg) []dns.RR {
+	if len(r.Question) == 0 {
+		return nil
+	}
 	question := r.Question[0]
-	record, found := d.records.Load(buildRecordKey(question.Name, question.Qclass, question.Qtype))
+	key := buildRecordKey(question.Name, question.Qclass, question.Qtype)
+
+	value, found := d.records.Load(key)
 	if !found {
 		return nil
 	}
 
-	return record.(dns.RR)
+	records, ok := value.([]dns.RR)
+	if !ok {
+		log.Errorf("failed to cast records to []dns.RR, records: %v", value)
+		return nil
+	}
+
+	// if there's more than one record, rotate them (round-robin)
+	if len(records) > 1 {
+		first := records[0]
+		records = append(records[1:], first)
+		d.records.Store(key, records)
+	}
+
+	return records
 }
 
-func (d *localResolver) registerRecord(record nbdns.SimpleRecord) error {
-	fullRecord, err := dns.NewRR(record.String())
+// registerRecord stores a new record by appending it to any existing list
+func (d *localResolver) registerRecord(record nbdns.SimpleRecord) (string, error) {
+	rr, err := dns.NewRR(record.String())
 	if err != nil {
-		return fmt.Errorf("register record: %w", err)
+		return "", fmt.Errorf("register record: %w", err)
 	}
 
-	fullRecord.Header().Rdlength = record.Len()
+	rr.Header().Rdlength = record.Len()
+	header := rr.Header()
+	key := buildRecordKey(header.Name, header.Class, header.Rrtype)
 
-	header := fullRecord.Header()
-	d.records.Store(buildRecordKey(header.Name, header.Class, header.Rrtype), fullRecord)
+	// load any existing slice of records, then append
+	existing, _ := d.records.LoadOrStore(key, []dns.RR{})
+	records := existing.([]dns.RR)
+	records = append(records, rr)
 
-	return nil
+	// store updated slice
+	d.records.Store(key, records)
+	return key, nil
 }
 
+// deleteRecord removes *all* records under the recordKey.
 func (d *localResolver) deleteRecord(recordKey string) {
 	d.records.Delete(dns.Fqdn(recordKey))
 }
 
+// buildRecordKey consistently generates a key: name_class_type
 func buildRecordKey(name string, class, qType uint16) string {
-	key := fmt.Sprintf("%s_%d_%d", name, class, qType)
-	return key
+	return fmt.Sprintf("%s_%d_%d", dns.Fqdn(name), class, qType)
 }
 
 func (d *localResolver) probeAvailability() {}

client/internal/dns/local_test.go

@@ -55,7 +55,7 @@ func TestLocalResolver_ServeDNS(t *testing.T) {
 			resolver := &localResolver{
 				registeredMap: make(registrationMap),
 			}
-			_ = resolver.registerRecord(testCase.inputRecord)
+			_, _ = resolver.registerRecord(testCase.inputRecord)
 			var responseMSG *dns.Msg
 			responseWriter := &mockResponseWriter{
 				WriteMsgFunc: func(m *dns.Msg) error {

client/internal/dns/server.go

@@ -393,18 +393,22 @@ func (s *DefaultServer) applyConfiguration(update nbdns.Config) error {
 		s.service.Stop()
 	}
 
-	localMuxUpdates, localRecords, err := s.buildLocalHandlerUpdate(update.CustomZones)
+	localMuxUpdates, localRecordsByDomain, err := s.buildLocalHandlerUpdate(update.CustomZones)
 	if err != nil {
 		return fmt.Errorf("not applying dns update, error: %v", err)
 	}
+
 	upstreamMuxUpdates, err := s.buildUpstreamHandlerUpdate(update.NameServerGroups)
 	if err != nil {
 		return fmt.Errorf("not applying dns update, error: %v", err)
 	}
 	muxUpdates := append(localMuxUpdates, upstreamMuxUpdates...) //nolint:gocritic
 
 	s.updateMux(muxUpdates)
-	s.updateLocalResolver(localRecords)
+
+	// register local records
+	s.updateLocalResolver(localRecordsByDomain)
+
 	s.currentConfig = dnsConfigToHostDNSConfig(update, s.service.RuntimeIP(), s.service.RuntimePort())
 
 	hostUpdate := s.currentConfig
@@ -434,9 +438,12 @@ func (s *DefaultServer) applyConfiguration(update nbdns.Config) error {
 	return nil
 }
 
-func (s *DefaultServer) buildLocalHandlerUpdate(customZones []nbdns.CustomZone) ([]handlerWrapper, map[string]nbdns.SimpleRecord, error) {
+func (s *DefaultServer) buildLocalHandlerUpdate(
+	customZones []nbdns.CustomZone,
+) ([]handlerWrapper, map[string][]nbdns.SimpleRecord, error) {
+
 	var muxUpdates []handlerWrapper
-	localRecords := make(map[string]nbdns.SimpleRecord, 0)
+	localRecords := make(map[string][]nbdns.SimpleRecord)
 
 	for _, customZone := range customZones {
 		if len(customZone.Records) == 0 {
@@ -449,15 +456,18 @@ func (s *DefaultServer) buildLocalHandlerUpdate(customZones []nbdns.CustomZone)
 			priority: PriorityMatchDomain,
 		})
 
+		// group all records under this domain
 		for _, record := range customZone.Records {
 			var class uint16 = dns.ClassINET
 			if record.Class != nbdns.DefaultClass {
 				return nil, nil, fmt.Errorf("received an invalid class type: %s", record.Class)
 			}
 			key := buildRecordKey(record.Name, class, uint16(record.Type))
-			localRecords[key] = record
+
+			localRecords[key] = append(localRecords[key], record)
 		}
 	}
+
 	return muxUpdates, localRecords, nil
 }
 
@@ -593,7 +603,8 @@ func (s *DefaultServer) updateMux(muxUpdates []handlerWrapper) {
 	s.dnsMuxMap = muxUpdateMap
 }
 
-func (s *DefaultServer) updateLocalResolver(update map[string]nbdns.SimpleRecord) {
+func (s *DefaultServer) updateLocalResolver(update map[string][]nbdns.SimpleRecord) {
+	// remove old records that are no longer present
 	for key := range s.localResolver.registeredMap {
 		_, found := update[key]
 		if !found {
@@ -602,12 +613,18 @@ func (s *DefaultServer) updateLocalResolver(update map[string]nbdns.SimpleRecord
 	}
 
 	updatedMap := make(registrationMap)
-	for key, record := range update {
-		err := s.localResolver.registerRecord(record)
-		if err != nil {
-			log.Warnf("got an error while registering the record (%s), error: %v", record.String(), err)
+	for _, recs := range update {
+		for _, rec := range recs {
+			// convert the record to a dns.RR and register
+			key, err := s.localResolver.registerRecord(rec)
+			if err != nil {
+				log.Warnf("got an error while registering the record (%s), error: %v",
+					rec.String(), err)
+				continue
+			}
+
+			updatedMap[key] = struct{}{}
 		}
-		updatedMap[key] = struct{}{}
 	}
 
 	s.localResolver.registeredMap = updatedMap

client/internal/dns/server_test.go

@@ -573,7 +573,7 @@ func TestDNSServerStartStop(t *testing.T) {
 			}
 			time.Sleep(100 * time.Millisecond)
 			defer dnsServer.Stop()
-			err = dnsServer.localResolver.registerRecord(zoneRecords[0])
+			_, err = dnsServer.localResolver.registerRecord(zoneRecords[0])
 			if err != nil {
 				t.Error(err)
 			}

client/internal/login.go

@@ -117,7 +117,7 @@ func doMgmLogin(ctx context.Context, mgmClient *mgm.GrpcClient, pubSSHKey []byte
 		config.DisableDNS,
 		config.DisableFirewall,
 	)
-	_, err = mgmClient.Login(*serverKey, sysInfo, pubSSHKey)
+	_, err = mgmClient.Login(*serverKey, sysInfo, pubSSHKey, config.DNSLabels)
 	return serverKey, err
 }