[client] Don't deactivate upstream resolvers on failure (#4128)

client/internal/engine.go

@@ -7,6 +7,7 @@ import (
 	"math/rand"
 	"net"
 	"net/netip"
+	"net/url"
 	"os"
 	"reflect"
 	"runtime"
@@ -33,6 +34,7 @@ import (
 	nbnetstack "github.com/netbirdio/netbird/client/iface/netstack"
 	"github.com/netbirdio/netbird/client/internal/acl"
 	"github.com/netbirdio/netbird/client/internal/dns"
+	dnsconfig "github.com/netbirdio/netbird/client/internal/dns/config"
 	"github.com/netbirdio/netbird/client/internal/dnsfwd"
 	"github.com/netbirdio/netbird/client/internal/ingressgw"
 	"github.com/netbirdio/netbird/client/internal/netflow"
@@ -345,7 +347,7 @@ func (e *Engine) Stop() error {
 // Start creates a new WireGuard tunnel interface and listens to events from Signal and Management services
 // Connections to remote peers are not established here.
 // However, they will be established once an event with a list of peers to connect to will be received from Management Service
-func (e *Engine) Start() error {
+func (e *Engine) Start(netbirdConfig *mgmProto.NetbirdConfig, mgmtURL *url.URL) error {
 	e.syncMsgMux.Lock()
 	defer e.syncMsgMux.Unlock()
 
@@ -401,6 +403,11 @@ func (e *Engine) Start() error {
 	}
 	e.dnsServer = dnsServer
 
+	// Populate DNS cache with NetbirdConfig and management URL for early resolution
+	if err := e.PopulateNetbirdConfig(netbirdConfig, mgmtURL); err != nil {
+		log.Warnf("failed to populate DNS cache: %v", err)
+	}
+
 	e.routeManager = routemanager.NewManager(routemanager.ManagerConfig{
 		Context:             e.ctx,
 		PublicKey:           e.config.WgPrivateKey.PublicKey().String(),
@@ -661,6 +668,30 @@ func (e *Engine) removePeer(peerKey string) error {
 	return nil
 }
 
+// PopulateNetbirdConfig populates the DNS cache with infrastructure domains from login response
+func (e *Engine) PopulateNetbirdConfig(netbirdConfig *mgmProto.NetbirdConfig, mgmtURL *url.URL) error {
+	if e.dnsServer == nil {
+		return nil
+	}
+
+	// Populate management URL if provided
+	if mgmtURL != nil {
+		if err := e.dnsServer.PopulateManagementDomain(mgmtURL); err != nil {
+			log.Warnf("failed to populate DNS cache with management URL: %v", err)
+		}
+	}
+
+	// Populate NetbirdConfig domains if provided
+	if netbirdConfig != nil {
+		serverDomains := dnsconfig.ExtractFromNetbirdConfig(netbirdConfig)
+		if err := e.dnsServer.UpdateServerConfig(serverDomains); err != nil {
+			return fmt.Errorf("update DNS server config from NetbirdConfig: %w", err)
+		}
+	}
+
+	return nil
+}
+
 func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 	e.syncMsgMux.Lock()
 	defer e.syncMsgMux.Unlock()
@@ -692,6 +723,10 @@ func (e *Engine) handleSync(update *mgmProto.SyncResponse) error {
 			return fmt.Errorf("handle the flow configuration: %w", err)
 		}
 
+		if err := e.PopulateNetbirdConfig(wCfg, nil); err != nil {
+			log.Warnf("Failed to update DNS server config: %v", err)
+		}
+
 		// todo update signal
 	}
 
@@ -1557,7 +1592,14 @@ func (e *Engine) newDnsServer(dnsConfig *nbdns.Config) (dns.Server, error) {
 		return dnsServer, nil
 
 	default:
-		dnsServer, err := dns.NewDefaultServer(e.ctx, e.wgInterface, e.config.CustomDNSAddress, e.statusRecorder, e.stateManager, e.config.DisableDNS)
+
+		dnsServer, err := dns.NewDefaultServer(e.ctx, dns.DefaultServerConfig{
+			WgInterface:    e.wgInterface,
+			CustomAddress:  e.config.CustomDNSAddress,
+			StatusRecorder: e.statusRecorder,
+			StateManager:   e.stateManager,
+			DisableSys:     e.config.DisableDNS,
+		})
 		if err != nil {
 			return nil, err
 		}