From 5288506c90909d140673a0ac427c847af12ffd57 Mon Sep 17 00:00:00 2001
From: Zoltan Papp <zoltan.pmail@gmail.com>
Date: Tue, 15 Aug 2023 17:01:01 +0200
Subject: [PATCH] Fix runtime/listen port logic

---
 client/internal/dns/server.go           |  6 ++++++
 client/internal/dns/service_listener.go | 21 +++++++++++++++------
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/client/internal/dns/server.go b/client/internal/dns/server.go
index db4b6c542..38d0a0bcc 100644
--- a/client/internal/dns/server.go
+++ b/client/internal/dns/server.go
@@ -235,6 +235,12 @@ func (s *DefaultServer) applyConfiguration(update nbdns.Config) error {
 	s.updateLocalResolver(localRecords)
 	s.currentConfig = dnsConfigToHostDNSConfig(update, s.service.ListenIp(), s.service.ListenPort())
 
+	if s.service.ListenPort() != defaultPort && !s.hostManager.supportCustomPort() {
+		log.Warnf("the DNS manager of this peer doesn't support custom port. Disabling primary DNS setup. " +
+			"Learn more at: https://netbird.io/docs/how-to-guides/nameservers#local-resolver")
+		s.currentConfig.routeAll = false
+	}
+
 	if err = s.hostManager.applyDNSConfig(s.currentConfig); err != nil {
 		log.Error(err)
 	}
diff --git a/client/internal/dns/service_listener.go b/client/internal/dns/service_listener.go
index c156095a3..1f12f570a 100644
--- a/client/internal/dns/service_listener.go
+++ b/client/internal/dns/service_listener.go
@@ -45,7 +45,10 @@ func newServiceViaListener(wgIface WGIface, customAddr *netip.AddrPort) *service
 			Handler: mux,
 			UDPSize: 65535,
 		},
-		ebpfService: ebpf.GetEbpfManagerInstance(),
+	}
+
+	if runtime.GOOS == "linux" {
+		s.ebpfService = ebpf.GetEbpfManagerInstance()
 	}
 	return s
 }
@@ -77,7 +80,7 @@ func (s *serviceViaListener) Listen() error {
 		}
 	}()
 
-	if s.runtimePort != defaultPort {
+	if s.ebpfService != nil && s.runtimePort != defaultPort {
 		err = s.ebpfService.LoadDNSFwd(s.runtimeIP, s.runtimePort)
 		if err != nil {
 			return err
@@ -102,9 +105,11 @@ func (s *serviceViaListener) Stop() {
 		log.Errorf("stopping dns server listener returned an error: %v", err)
 	}
 
-	err = s.ebpfService.FreeDNSFwd()
-	if err != nil {
-		log.Errorf("stopping traffic forwarder returned an error: %v", err)
+	if s.ebpfService != nil {
+		err = s.ebpfService.FreeDNSFwd()
+		if err != nil {
+			log.Errorf("stopping traffic forwarder returned an error: %v", err)
+		}
 	}
 }
 
@@ -117,7 +122,11 @@ func (s *serviceViaListener) DeregisterMux(pattern string) {
 }
 
 func (s *serviceViaListener) ListenPort() int {
-	return defaultPort
+	if s.ebpfService != nil {
+		return defaultPort
+	} else {
+		return s.runtimePort
+	}
 }
 
 func (s *serviceViaListener) ListenIp() string {