Fix DNS resolution for routes on iOS (#2378)

client/internal/dns/server.go

@@ -94,7 +94,7 @@ func NewDefaultServer(
 
 	var dnsService service
 	if wgInterface.IsUserspaceBind() {
-		dnsService = newServiceViaMemory(wgInterface)
+		dnsService = NewServiceViaMemory(wgInterface)
 	} else {
 		dnsService = newServiceViaListener(wgInterface, addrPort)
 	}
@@ -112,7 +112,7 @@ func NewDefaultServerPermanentUpstream(
 	statusRecorder *peer.Status,
 ) *DefaultServer {
 	log.Debugf("host dns address list is: %v", hostsDnsList)
-	ds := newDefaultServer(ctx, wgInterface, newServiceViaMemory(wgInterface), statusRecorder)
+	ds := newDefaultServer(ctx, wgInterface, NewServiceViaMemory(wgInterface), statusRecorder)
 	ds.hostsDNSHolder.set(hostsDnsList)
 	ds.permanent = true
 	ds.addHostRootZone()
@@ -130,7 +130,7 @@ func NewDefaultServerIos(
 	iosDnsManager IosDnsManager,
 	statusRecorder *peer.Status,
 ) *DefaultServer {
-	ds := newDefaultServer(ctx, wgInterface, newServiceViaMemory(wgInterface), statusRecorder)
+	ds := newDefaultServer(ctx, wgInterface, NewServiceViaMemory(wgInterface), statusRecorder)
 	ds.iosDnsManager = iosDnsManager
 	return ds
 }

client/internal/dns/server_test.go

@@ -534,7 +534,7 @@ func TestDNSServerStartStop(t *testing.T) {
 func TestDNSServerUpstreamDeactivateCallback(t *testing.T) {
 	hostManager := &mockHostConfigurator{}
 	server := DefaultServer{
-		service: newServiceViaMemory(&mocWGIface{}),
+		service: NewServiceViaMemory(&mocWGIface{}),
 		localResolver: &localResolver{
 			registeredMap: make(registrationMap),
 		},

client/internal/dns/service_memory.go

@@ -12,7 +12,7 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-type serviceViaMemory struct {
+type ServiceViaMemory struct {
 	wgInterface       WGIface
 	dnsMux            *dns.ServeMux
 	runtimeIP         string
@@ -22,8 +22,8 @@ type serviceViaMemory struct {
 	listenerFlagLock  sync.Mutex
 }
 
-func newServiceViaMemory(wgIface WGIface) *serviceViaMemory {
+func NewServiceViaMemory(wgIface WGIface) *ServiceViaMemory {
-	s := &serviceViaMemory{
+	s := &ServiceViaMemory{
 		wgInterface: wgIface,
 		dnsMux:      dns.NewServeMux(),
 
@@ -33,7 +33,7 @@ func newServiceViaMemory(wgIface WGIface) *serviceViaMemory {
 	return s
 }
 
-func (s *serviceViaMemory) Listen() error {
+func (s *ServiceViaMemory) Listen() error {
 	s.listenerFlagLock.Lock()
 	defer s.listenerFlagLock.Unlock()
 
@@ -52,7 +52,7 @@ func (s *serviceViaMemory) Listen() error {
 	return nil
 }
 
-func (s *serviceViaMemory) Stop() {
+func (s *ServiceViaMemory) Stop() {
 	s.listenerFlagLock.Lock()
 	defer s.listenerFlagLock.Unlock()
 
@@ -67,23 +67,23 @@ func (s *serviceViaMemory) Stop() {
 	s.listenerIsRunning = false
 }
 
-func (s *serviceViaMemory) RegisterMux(pattern string, handler dns.Handler) {
+func (s *ServiceViaMemory) RegisterMux(pattern string, handler dns.Handler) {
 	s.dnsMux.Handle(pattern, handler)
 }
 
-func (s *serviceViaMemory) DeregisterMux(pattern string) {
+func (s *ServiceViaMemory) DeregisterMux(pattern string) {
 	s.dnsMux.HandleRemove(pattern)
 }
 
-func (s *serviceViaMemory) RuntimePort() int {
+func (s *ServiceViaMemory) RuntimePort() int {
 	return s.runtimePort
 }
 
-func (s *serviceViaMemory) RuntimeIP() string {
+func (s *ServiceViaMemory) RuntimeIP() string {
 	return s.runtimeIP
 }
 
-func (s *serviceViaMemory) filterDNSTraffic() (string, error) {
+func (s *ServiceViaMemory) filterDNSTraffic() (string, error) {
 	filter := s.wgInterface.GetFilter()
 	if filter == nil {
 		return "", fmt.Errorf("can't set DNS filter, filter not initialized")

client/internal/dns/upstream_ios.go

@@ -4,6 +4,7 @@ package dns
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"syscall"
 	"time"
@@ -17,9 +18,9 @@ import (
 
 type upstreamResolverIOS struct {
 	*upstreamResolverBase
-	lIP    net.IP
+	lIP           net.IP
-	lNet   *net.IPNet
+	lNet          *net.IPNet
-	iIndex int
+	interfaceName string
 }
 
 func newUpstreamResolver(
@@ -32,17 +33,11 @@ func newUpstreamResolver(
 ) (*upstreamResolverIOS, error) {
 	upstreamResolverBase := newUpstreamResolverBase(ctx, statusRecorder)
 
-	index, err := getInterfaceIndex(interfaceName)
-	if err != nil {
-		log.Debugf("unable to get interface index for %s: %s", interfaceName, err)
-		return nil, err
-	}
-
 	ios := &upstreamResolverIOS{
 		upstreamResolverBase: upstreamResolverBase,
 		lIP:                  ip,
 		lNet:                 net,
-		iIndex:               index,
+		interfaceName:        interfaceName,
 	}
 	ios.upstreamClient = ios
 
@@ -53,7 +48,7 @@ func (u *upstreamResolverIOS) exchange(ctx context.Context, upstream string, r *
 	client := &dns.Client{}
 	upstreamHost, _, err := net.SplitHostPort(upstream)
 	if err != nil {
-		log.Errorf("error while parsing upstream host: %s", err)
+		return nil, 0, fmt.Errorf("error while parsing upstream host: %s", err)
 	}
 
 	timeout := upstreamTimeout
@@ -65,26 +60,35 @@ func (u *upstreamResolverIOS) exchange(ctx context.Context, upstream string, r *
 	upstreamIP := net.ParseIP(upstreamHost)
 	if u.lNet.Contains(upstreamIP) || net.IP.IsPrivate(upstreamIP) {
 		log.Debugf("using private client to query upstream: %s", upstream)
-		client = u.getClientPrivate(timeout)
+		client, err = GetClientPrivate(u.lIP, u.interfaceName, timeout)
+		if err != nil {
+			return nil, 0, fmt.Errorf("error while creating private client: %s", err)
+		}
 	}
 
 	// Cannot use client.ExchangeContext because it overwrites our Dialer
 	return client.Exchange(r, upstream)
 }
 
-// getClientPrivate returns a new DNS client bound to the local IP address of the Netbird interface
+// GetClientPrivate returns a new DNS client bound to the local IP address of the Netbird interface
 // This method is needed for iOS
-func (u *upstreamResolverIOS) getClientPrivate(dialTimeout time.Duration) *dns.Client {
+func GetClientPrivate(ip net.IP, interfaceName string, dialTimeout time.Duration) (*dns.Client, error) {
+	index, err := getInterfaceIndex(interfaceName)
+	if err != nil {
+		log.Debugf("unable to get interface index for %s: %s", interfaceName, err)
+		return nil, err
+	}
+
 	dialer := &net.Dialer{
 		LocalAddr: &net.UDPAddr{
-			IP:   u.lIP,
+			IP:   ip,
 			Port: 0, // Let the OS pick a free port
 		},
 		Timeout: dialTimeout,
 		Control: func(network, address string, c syscall.RawConn) error {
 			var operr error
 			fn := func(s uintptr) {
-				operr = unix.SetsockoptInt(int(s), unix.IPPROTO_IP, unix.IP_BOUND_IF, u.iIndex)
+				operr = unix.SetsockoptInt(int(s), unix.IPPROTO_IP, unix.IP_BOUND_IF, index)
 			}
 
 			if err := c.Control(fn); err != nil {
@@ -101,7 +105,7 @@ func (u *upstreamResolverIOS) getClientPrivate(dialTimeout time.Duration) *dns.C
 	client := &dns.Client{
 		Dialer: dialer,
 	}
-	return client
+	return client, nil
 }
 
 func getInterfaceIndex(interfaceName string) (int, error) {

client/internal/routemanager/client.go

@@ -10,6 +10,7 @@ import (
 	log "github.com/sirupsen/logrus"
 
 	nberrors "github.com/netbirdio/netbird/client/errors"
+	nbdns "github.com/netbirdio/netbird/client/internal/dns"
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/routemanager/dynamic"
 	"github.com/netbirdio/netbird/client/internal/routemanager/refcounter"
@@ -65,7 +66,7 @@ func newClientNetworkWatcher(ctx context.Context, dnsRouteInterval time.Duration
 		routePeersNotifiers: make(map[string]chan struct{}),
 		routeUpdate:         make(chan routesUpdate),
 		peerStateUpdate:     make(chan struct{}),
-		handler:             handlerFromRoute(rt, routeRefCounter, allowedIPsRefCounter, dnsRouteInterval, statusRecorder),
+		handler:             handlerFromRoute(rt, routeRefCounter, allowedIPsRefCounter, dnsRouteInterval, statusRecorder, wgInterface),
 	}
 	return client
 }
@@ -383,9 +384,10 @@ func (c *clientNetwork) peersStateAndUpdateWatcher() {
 	}
 }
 
-func handlerFromRoute(rt *route.Route, routeRefCounter *refcounter.RouteRefCounter, allowedIPsRefCounter *refcounter.AllowedIPsRefCounter, dnsRouterInteval time.Duration, statusRecorder *peer.Status) RouteHandler {
+func handlerFromRoute(rt *route.Route, routeRefCounter *refcounter.RouteRefCounter, allowedIPsRefCounter *refcounter.AllowedIPsRefCounter, dnsRouterInteval time.Duration, statusRecorder *peer.Status, wgInterface *iface.WGIface) RouteHandler {
 	if rt.IsDynamic() {
-		return dynamic.NewRoute(rt, routeRefCounter, allowedIPsRefCounter, dnsRouterInteval, statusRecorder)
+		dns := nbdns.NewServiceViaMemory(wgInterface)
+		return dynamic.NewRoute(rt, routeRefCounter, allowedIPsRefCounter, dnsRouterInteval, statusRecorder, wgInterface, fmt.Sprintf("%s:%d", dns.RuntimeIP(), dns.RuntimePort()))
 	}
 	return static.NewRoute(rt, routeRefCounter, allowedIPsRefCounter)
 }

client/internal/routemanager/dynamic/route.go

@@ -16,6 +16,7 @@ import (
 	"github.com/netbirdio/netbird/client/internal/peer"
 	"github.com/netbirdio/netbird/client/internal/routemanager/refcounter"
 	"github.com/netbirdio/netbird/client/internal/routemanager/util"
+	"github.com/netbirdio/netbird/iface"
 	"github.com/netbirdio/netbird/management/domain"
 	"github.com/netbirdio/netbird/route"
 )
@@ -47,6 +48,8 @@ type Route struct {
 	currentPeerKey       string
 	cancel               context.CancelFunc
 	statusRecorder       *peer.Status
+	wgInterface          *iface.WGIface
+	resolverAddr         string
 }
 
 func NewRoute(
@@ -55,6 +58,8 @@ func NewRoute(
 	allowedIPsRefCounter *refcounter.AllowedIPsRefCounter,
 	interval time.Duration,
 	statusRecorder *peer.Status,
+	wgInterface *iface.WGIface,
+	resolverAddr string,
 ) *Route {
 	return &Route{
 		route:                rt,
@@ -63,6 +68,8 @@ func NewRoute(
 		interval:             interval,
 		dynamicDomains:       domainMap{},
 		statusRecorder:       statusRecorder,
+		wgInterface:          wgInterface,
+		resolverAddr:         resolverAddr,
 	}
 }
 
@@ -228,11 +235,17 @@ func (r *Route) resolve(results chan resolveResult) {
 		wg.Add(1)
 		go func(domain domain.Domain) {
 			defer wg.Done()
-			ips, err := net.LookupIP(string(domain))
+
+			ips, err := r.getIPsFromResolver(domain)
 			if err != nil {
-				results <- resolveResult{domain: domain, err: fmt.Errorf("resolve d %s: %w", domain.SafeString(), err)}
+				log.Tracef("Failed to resolve domain %s with private resolver: %v", domain.SafeString(), err)
-				return
+				ips, err = net.LookupIP(string(domain))
+				if err != nil {
+					results <- resolveResult{domain: domain, err: fmt.Errorf("resolve d %s: %w", domain.SafeString(), err)}
+					return
+				}
 			}
+
 			for _, ip := range ips {
 				prefix, err := util.GetPrefixFromIP(ip)
 				if err != nil {

client/internal/routemanager/dynamic/route_generic.go

@@ -0,0 +1,13 @@
+//go:build !ios
+
+package dynamic
+
+import (
+	"net"
+
+	"github.com/netbirdio/netbird/management/domain"
+)
+
+func (r *Route) getIPsFromResolver(domain domain.Domain) ([]net.IP, error) {
+	return net.LookupIP(string(domain))
+}

client/internal/routemanager/dynamic/route_ios.go

@@ -0,0 +1,55 @@
+//go:build ios
+
+package dynamic
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/miekg/dns"
+
+	nbdns "github.com/netbirdio/netbird/client/internal/dns"
+
+	"github.com/netbirdio/netbird/management/domain"
+)
+
+const dialTimeout = 10 * time.Second
+
+func (r *Route) getIPsFromResolver(domain domain.Domain) ([]net.IP, error) {
+	privateClient, err := nbdns.GetClientPrivate(r.wgInterface.Address().IP, r.wgInterface.Name(), dialTimeout)
+	if err != nil {
+		return nil, fmt.Errorf("error while creating private client: %s", err)
+	}
+
+	msg := new(dns.Msg)
+	msg.SetQuestion(dns.Fqdn(string(domain)), dns.TypeA)
+
+	startTime := time.Now()
+
+	response, _, err := privateClient.Exchange(msg, r.resolverAddr)
+	if err != nil {
+		return nil, fmt.Errorf("DNS query for %s failed after %s: %s ", domain.SafeString(), time.Since(startTime), err)
+	}
+
+	if response.Rcode != dns.RcodeSuccess {
+		return nil, fmt.Errorf("dns response code: %s", dns.RcodeToString[response.Rcode])
+	}
+
+	ips := make([]net.IP, 0)
+
+	for _, answ := range response.Answer {
+		if aRecord, ok := answ.(*dns.A); ok {
+			ips = append(ips, aRecord.A)
+		}
+		if aaaaRecord, ok := answ.(*dns.AAAA); ok {
+			ips = append(ips, aaaaRecord.AAAA)
+		}
+	}
+
+	if len(ips) == 0 {
+		return nil, fmt.Errorf("no A or AAAA records found for %s", domain.SafeString())
+	}
+
+	return ips, nil
+}