Fix iOS DNS timeout (netbirdio#1504)

Foosec · Jan 29, 2024 · 8b28781 · 8b28781
1 parent f6ffc31
commit 8b28781
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Showing 6 changed files with 19 additions and 29 deletions.
diff --git a/client/internal/dns/file_parser_linux_test.go b/client/internal/dns/file_parser_linux_test.go
@@ -16,11 +16,11 @@ func Test_parseResolvConf(t *testing.T) {
 		expectedOther  []string
 	}{
 		{
-			input: `domain chello.hu
-search chello.hu
+			input: `domain example.org
+search example.org
 nameserver 192.168.0.1
 `,
-			expectedSearch: []string{"chello.hu"},
+			expectedSearch: []string{"example.org"},
 			expectedNS:     []string{"192.168.0.1"},
 			expectedOther:  []string{},
 		},

diff --git a/client/internal/dns/file_repair_linux.go b/client/internal/dns/file_repair_linux.go
@@ -87,7 +87,7 @@ func (f *repair) watchFileChanges(nbSearchDomains []string, nbNameserverIP strin
 
 			err = f.inotify.Add(f.watchDir)
 			if err != nil {
-				log.Errorf("failed to readd inotify watch for resolv.conf: %s", err)
+				log.Errorf("failed to re-add inotify watch for resolv.conf: %s", err)
 				return
 			}
 		}

diff --git a/client/internal/dns/upstream.go b/client/internal/dns/upstream.go
@@ -25,8 +25,7 @@ const (
 const testRecord = "."
 
 type upstreamClient interface {
-	exchange(upstream string, r *dns.Msg) (*dns.Msg, time.Duration, error)
-	exchangeContext(ctx context.Context, upstream string, r *dns.Msg) (*dns.Msg, time.Duration, error)
+	exchange(ctx context.Context, upstream string, r *dns.Msg) (*dns.Msg, time.Duration, error)
 }
 
 type UpstreamResolver interface {
@@ -80,8 +79,15 @@ func (u *upstreamResolverBase) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	}
 
 	for _, upstream := range u.upstreamServers {
-
-		rm, t, err := u.upstreamClient.exchange(upstream, r)
+		var rm *dns.Msg
+		var t time.Duration
+		var err error
+
+		func() {
+			ctx, cancel := context.WithTimeout(u.ctx, u.upstreamTimeout)
+			defer cancel()
+			rm, t, err = u.upstreamClient.exchange(ctx, upstream, r)
+		}()
 
 		if err != nil {
 			if errors.Is(err, context.DeadlineExceeded) || isTimeout(err) {
@@ -259,6 +265,6 @@ func (u *upstreamResolverBase) testNameserver(server string) error {
 
 	r := new(dns.Msg).SetQuestion(testRecord, dns.TypeSOA)
 
-	_, _, err := u.upstreamClient.exchangeContext(ctx, server, r)
+	_, _, err := u.upstreamClient.exchange(ctx, server, r)
 	return err
 }
diff --git a/client/internal/dns/upstream_ios.go b/client/internal/dns/upstream_ios.go
@@ -40,11 +40,7 @@ func newUpstreamResolver(parentCTX context.Context, interfaceName string, ip net
 	return ios, nil
 }
 
-func (u *upstreamResolverIOS) exchange(upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
-	return u.exchangeContext(context.Background(), upstream, r)
-}
-
-func (u *upstreamResolverIOS) exchangeContext(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
+func (u *upstreamResolverIOS) exchange(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
 	client := &dns.Client{}
 	upstreamHost, _, err := net.SplitHostPort(upstream)
 	if err != nil {

diff --git a/client/internal/dns/upstream_nonios.go b/client/internal/dns/upstream_nonios.go
@@ -23,14 +23,7 @@ func newUpstreamResolver(parentCTX context.Context, interfaceName string, ip net
 	return nonIOS, nil
 }
 
-func (u *upstreamResolverNonIOS) exchange(upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
-	// default upstream timeout
-	ctx, cancel := context.WithTimeout(u.ctx, u.upstreamTimeout)
-	defer cancel()
-	return u.exchangeContext(ctx, upstream, r)
-}
-
-func (u *upstreamResolverNonIOS) exchangeContext(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
+func (u *upstreamResolverNonIOS) exchange(ctx context.Context, upstream string, r *dns.Msg) (rm *dns.Msg, t time.Duration, err error) {
 	upstreamExchangeClient := &dns.Client{}
 	return upstreamExchangeClient.ExchangeContext(ctx, r, upstream)
 }
diff --git a/client/internal/dns/upstream_test.go b/client/internal/dns/upstream_test.go
@@ -105,13 +105,8 @@ type mockUpstreamResolver struct {
 	err error
 }
 
-// Exchange mock implementation of Exchangefrom upstreamResolver
-func (c mockUpstreamResolver) exchange(upstream string, r *dns.Msg) (*dns.Msg, time.Duration, error) {
-	return c.exchangeContext(context.Background(), upstream, r)
-}
-
-// ExchangeContext mock implementation of ExchangeContext from upstreamResolver
-func (c mockUpstreamResolver) exchangeContext(_ context.Context, _ string, _ *dns.Msg) (*dns.Msg, time.Duration, error) {
+// exchange mock implementation of exchange from upstreamResolver
+func (c mockUpstreamResolver) exchange(_ context.Context, _ string, _ *dns.Msg) (*dns.Msg, time.Duration, error) {
 	return c.r, c.rtt, c.err
 }