Fix DNS resolution for routes on iOS (#2378)

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)}
-				return
+				log.Tracef("Failed to resolve domain %s with private resolver: %v", domain.SafeString(), err)
+				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
+}