From 2fdbe5c0ca19b5dfee494d285204e68eb93a0b7e Mon Sep 17 00:00:00 2001
From: zarazaex69 <zarazaex@tuta.io>
Date: Sat, 16 May 2026 18:22:02 +0300
Subject: [PATCH] fix(session): apply custom DNS before connect

---
 go.sum                          |  2 --
 internal/app/session/session.go | 17 ++++++++++++++++-
 internal/server/server.go       | 14 +++++++-------
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/go.sum b/go.sum
index bf58883..8c428f1 100644
--- a/go.sum
+++ b/go.sum
@@ -235,8 +235,6 @@ github.com/xtaci/smux v1.5.57/go.mod h1:IGQ9QYrBphmb/4aTnLEcJby0TNr3NV+OslIOMrX8
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 github.com/zarazaex69/gr v0.0.0-20260430043628-45b595f4fef0 h1:dMjHX/YPV3ZD/KJKFjQdlMBwj2/rZIuOVKOvGv26m9k=
 github.com/zarazaex69/gr v0.0.0-20260430043628-45b595f4fef0/go.mod h1:7vALI2tjaLTOGiDKV7V2JkVU9bA1YADBDQA6uvpp1ac=
-github.com/zarazaex69/j v0.0.0-20260515222039-806b50503e36 h1:0MNDFrI0gsXivKHSK1YSLqTkrOzYk5QXZeii04Bx714=
-github.com/zarazaex69/j v0.0.0-20260515222039-806b50503e36/go.mod h1:7/ypJTenOIPx23fpo5uF7l4u+rxZqg9cFbTL/N77Ktc=
 github.com/zarazaex69/j v0.0.0-20260516013155-bffcfe38e7d9 h1:hsD5J10K8xUJ1AOg2A5SLYDSCz/tw7WOOoaiO69KafY=
 github.com/zarazaex69/j v0.0.0-20260516013155-bffcfe38e7d9/go.mod h1:7/ypJTenOIPx23fpo5uF7l4u+rxZqg9cFbTL/N77Ktc=
 github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
diff --git a/internal/app/session/session.go b/internal/app/session/session.go
index f901cd6..e9b3226 100644
--- a/internal/app/session/session.go
+++ b/internal/app/session/session.go
@@ -600,6 +600,7 @@ func isLoopbackListenHost(host string) bool {
 func Run(ctx context.Context, cfg Config) error {
 	cfg = ApplyTransportDefaults(cfg)
 	cfg = ApplyLivenessDefaults(cfg)
+	configureDefaultResolver(cfg.DNSServer)
 	roomURL := cfg.RoomID
 	liveness, err := livenessConfig(cfg)
 	if err != nil {
@@ -623,6 +624,19 @@ func Run(ctx context.Context, cfg Config) error {
 	return run(ctx)
 }
 
+func configureDefaultResolver(dnsServer string) {
+	if dnsServer == "" {
+		return
+	}
+	net.DefaultResolver = &net.Resolver{
+		PreferGo: true,
+		Dial: func(ctx context.Context, network, _ string) (net.Conn, error) {
+			d := net.Dialer{Timeout: 3 * time.Second}
+			return d.DialContext(ctx, network, dnsServer)
+		},
+	}
+}
+
 func runOnce(
 	ctx context.Context,
 	cfg Config,
@@ -775,6 +789,7 @@ func genRetry(ctx context.Context, fn func(context.Context) error) error {
 
 // Gen creates cfg.Amount rooms for the configured auth provider and writes each room ID to out.
 func Gen(ctx context.Context, cfg Config, out func(string)) error {
+	configureDefaultResolver(cfg.DNSServer)
 	p, err := auth.Get(cfg.Auth)
 	if err != nil {
 		return fmt.Errorf("%w: %s", ErrUnsupportedCarrier, cfg.Auth)
@@ -787,7 +802,7 @@ func Gen(ctx context.Context, cfg Config, out func(string)) error {
 		var roomID string
 		err := genRetry(ctx, func(ctx context.Context) error {
 			var genErr error
-			roomID, genErr = creator.CreateRoom(ctx, auth.Config{Name: names.Generate()})
+			roomID, genErr = creator.CreateRoom(ctx, auth.Config{Name: names.Generate(), DNSServer: cfg.DNSServer})
 			if genErr != nil {
 				return fmt.Errorf("CreateRoom: %w", genErr)
 			}
diff --git a/internal/server/server.go b/internal/server/server.go
index 338d8fd..5b3589e 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -247,13 +247,13 @@ func (s *Server) bringUpLink(
 	})
 
 	logger.Infof("Connecting transport=%s carrier=%s ...", cfg.Transport, cfg.Carrier)
+	s.installSession()
+
 	if err := ln.Connect(ctx); err != nil {
 		return fmt.Errorf("failed to connect link: %w", err)
 	}
 	logger.Infof("Link connected")
 
-	s.installSession()
-
 	s.wg.Add(1)
 	go func() {
 		defer s.wg.Done()
@@ -517,11 +517,11 @@ func (s *Server) Status() control.Status {
 	return s.health.Status()
 }
 
-func (s *Server) recordSession(sessionID string)  { s.health.RecordSession(sessionID) }
-func (s *Server) recordPong(h control.Health)     { s.health.RecordPong(h) }
-func (s *Server) recordMissed(missed int)         { s.health.RecordMissed(missed) }
-func (s *Server) recordUnhealthy(missed int)      { s.health.RecordUnhealthy(missed) }
-func (s *Server) recordReconnect()                { s.health.RecordReconnect() }
+func (s *Server) recordSession(sessionID string) { s.health.RecordSession(sessionID) }
+func (s *Server) recordPong(h control.Health)    { s.health.RecordPong(h) }
+func (s *Server) recordMissed(missed int)        { s.health.RecordMissed(missed) }
+func (s *Server) recordUnhealthy(missed int)     { s.health.RecordUnhealthy(missed) }
+func (s *Server) recordReconnect()               { s.health.RecordReconnect() }
 
 func (s *Server) shutdown() {
 	s.closeSession()