From 43fbf77ab9ecdd0caec7a57a05f0b6bac9624553 Mon Sep 17 00:00:00 2001
From: dviejokfs <dviejo@kungfusoftware.es>
Date: Sat, 4 Feb 2023 22:36:57 +0100
Subject: [PATCH] Improve code legibility

---
 cmd/server/server.go | 43 ++++++++++++++++---------------------------
 1 file changed, 16 insertions(+), 27 deletions(-)

diff --git a/cmd/server/server.go b/cmd/server/server.go
index c56f72b..7c99296 100644
--- a/cmd/server/server.go
+++ b/cmd/server/server.go
@@ -43,11 +43,17 @@ type SessionRegistry struct {
 	sessions map[string]*Session
 }
 
-func (s Session) cleanup() {
+func (s *Session) cleanup() {
+	defer func() {
+		s.cleanupDone = true
+	}()
+	if s.cleanupDone {
+		return
+	}
 	if s.Conn != nil {
 		s.Conn.Close()
 	}
-	if s.Sess != nil {
+	if s.Sess != nil && !s.Sess.IsClosed() {
 		s.Sess.Close()
 	}
 	if s.Mux != nil {
@@ -93,6 +99,7 @@ func (r *SessionRegistry) find(sni string) *Session {
 	return s
 }
 func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) error {
+	defer conn.Close()
 	log.Debugf("client %s connected", conn.RemoteAddr().String())
 	config := yamux.DefaultConfig()
 	// setup session
@@ -101,10 +108,10 @@ func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) erro
 		log.Errorf("failed to create yamux session")
 		return err
 	}
+	defer sess.Close()
 	// accept connection
 	initialConn, err := sess.Accept()
 	if err != nil {
-		defer sess.Close()
 		log.Debugf("client %s disconnected", conn.RemoteAddr().String())
 		log.Errorf("multiplex conn accept failed %v", err)
 		return err
@@ -118,8 +125,6 @@ func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) erro
 	sni := msg.GetTls().GetSni()
 	s := c.sessionRegistry.find(sni)
 	if s != nil {
-		defer conn.Close()
-		defer sess.Close()
 		log.Debugf("Session already exists in the registry for %s", sni)
 		err = c.returnResponse(initialConn, messages.TunnelStatus_ALREADY_EXISTS)
 		if err != nil {
@@ -132,11 +137,6 @@ func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) erro
 		if msg != nil {
 			log.Errorf("failed to listen on %s", msg.GetTls().GetSni())
 		}
-		if muxListener != nil {
-			muxListener.Close()
-		}
-		defer conn.Close()
-		defer sess.Close()
 		if strings.Contains(strings.ToLower(err.Error()), "already bound") {
 			err = c.returnResponse(initialConn, messages.TunnelStatus_ALREADY_EXISTS)
 			if err != nil {
@@ -152,10 +152,13 @@ func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) erro
 		Mux:  muxListener,
 		Sess: sess,
 	}
+	defer func() {
+		session.cleanup()
+		c.sessionRegistry.delete(sni)
+	}()
 	err = c.sessionRegistry.store(sni, session)
 	if err != nil {
 		log.Errorf("failed to store session for %s", sni)
-		session.cleanup()
 		return err
 	}
 	err = c.returnResponse(initialConn, messages.TunnelStatus_OK)
@@ -164,20 +167,10 @@ func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) erro
 		if err != nil {
 			log.Warnf("Failed to send response: %v", err)
 		}
-		c.sessionRegistry.delete(sni)
 		return err
 	}
-	defer func() {
-		c.sessionRegistry.delete(sni)
-		if r := recover(); r != nil {
-			log.Infof("Recovered in request dispatcher %v", r)
-		}
-	}()
 	go func() {
 		log.Debugf("Checking if session %s is alive", sni)
-		defer func() {
-			c.sessionRegistry.delete(sni)
-		}()
 		for {
 			_, err = sess.Ping()
 			if err != nil {
@@ -193,7 +186,6 @@ func (c *serverCmd) handleTunnelRequest(mux *vhost.TLSMuxer, conn net.Conn) erro
 		conn, err := muxListener.Accept()
 		if err != nil {
 			log.Errorf("Error accepting connection", err)
-			c.sessionRegistry.delete(sni)
 			if strings.Contains(strings.ToLower(err.Error()), "listener closed") {
 				log.Info("listener closed")
 				return errors.New("listener closed")
@@ -263,10 +255,6 @@ func (c *serverCmd) run() error {
 	if err != nil {
 		panic(fmt.Errorf("error listening on %s: %w", c.tunnelAddr, err))
 	}
-	defer func(muxServer net.Listener) {
-		log.Warnf("Closing mux server %s", muxServer.Addr())
-		_ = muxServer.Close()
-	}(muxServer)
 	go func() {
 		log.Infof("tunnel listening on %s", c.tunnelAddr)
 		defer func() {
@@ -353,7 +341,8 @@ func NewServerCmd() *cobra.Command {
 }
 
 type Session struct {
-	SNI string `json:"sni"`
+	cleanupDone bool
+	SNI         string `json:"sni"`
 	//RemoteAddr string `json:"remoteAddr"`
 	//LocalAddr  string `json:"localAddr"`
 	Conn net.Conn