generalized redial routine

Signed-off-by: He Xian <hexian000@outlook.com>

v2/tunnel.go

@@ -24,17 +24,19 @@ type Tunnel struct {
 	l           hlistener.Listener
 	mu          sync.RWMutex
 	mux         map[*yamux.Session]string // map[mux]tag
+	redialSig   chan struct{}
 	redialCount int
 	dialMu      sync.Mutex
 	lastChanged time.Time
 }
 
 func NewTunnel(s *Server, c *TunnelConfig) *Tunnel {
 	return &Tunnel{
-		name: c.Identity,
-		s:    s,
-		c:    c,
-		mux:  make(map[*yamux.Session]string),
+		name:      c.Identity,
+		s:         s,
+		c:         c,
+		mux:       make(map[*yamux.Session]string),
+		redialSig: make(chan struct{}, 1),
 	}
 }
 
@@ -96,10 +98,10 @@ func (t *Tunnel) redial() {
 }
 
 func (t *Tunnel) scheduleRedial() <-chan time.Time {
-	n := t.redialCount - 1
-	if n < 0 {
+	if !t.s.c.Redial || t.c.MuxDial == "" || t.redialCount < 1 {
 		return make(<-chan time.Time)
 	}
+	n := t.redialCount - 1
 	var waitTimeConst = [...]time.Duration{
 		200 * time.Millisecond,
 		2 * time.Second,
@@ -118,18 +120,6 @@ func (t *Tunnel) scheduleRedial() <-chan time.Time {
 	return time.After(waitTime)
 }
 
-func (t *Tunnel) runWithRedial() {
-	for {
-		t.redial()
-		select {
-		case <-t.scheduleRedial():
-		case <-t.s.g.CloseC():
-			// server shutdown
-			return
-		}
-	}
-}
-
 func (t *Tunnel) run() {
 	defer func() {
 		t.mu.Lock()
@@ -139,11 +129,16 @@ func (t *Tunnel) run() {
 			delete(t.mux, mux)
 		}
 	}()
-	if t.s.c.Redial {
-		t.runWithRedial()
-		return
+	for {
+		t.redial()
+		select {
+		case <-t.redialSig:
+		case <-t.scheduleRedial():
+		case <-t.s.g.CloseC():
+			// server shutdown
+			return
+		}
 	}
-	<-t.s.g.CloseC()
 }
 
 func (t *Tunnel) addMux(mux *yamux.Session, isDialed bool) {
@@ -197,6 +192,10 @@ func (t *Tunnel) delMux(mux *yamux.Session) {
 	}
 	t.s.numSessions.Add(uint32(len(t.mux) - num))
 	t.lastChanged = now
+	select {
+	case t.redialSig <- struct{}{}:
+	default:
+	}
 }
 
 func (t *Tunnel) getMux() *yamux.Session {
@@ -233,7 +232,6 @@ func (t *Tunnel) dial(ctx context.Context) (*yamux.Session, error) {
 		return nil, ErrDialInProgress
 	}
 	defer t.dialMu.Unlock()
-	// try again with dialMu acquired
 	if mux := t.getMux(); mux != nil {
 		return mux, nil
 	}