TUN-2955: Fix connection and goroutine leaks when tunnel conection is terminated on error. Only unregister tunnels that had connected successfully. Close edge connection used to unregister the tunnel. Use buffered channels for error channels where receiver may quit early on context cancellation.

h2mux/h2mux.go

@@ -206,9 +206,9 @@ func Handshake(
 		initialStreamWindow:     m.config.DefaultWindowSize,
 		streamWindowMax:         m.config.MaxWindowSize,
 		streamWriteBufferMaxLen: m.config.StreamWriteBufferMaxLen,
-		r:                       m.r,
-		metricsUpdater:          m.muxMetricsUpdater,
-		bytesRead:               inBoundCounter,
+		r:              m.r,
+		metricsUpdater: m.muxMetricsUpdater,
+		bytesRead:      inBoundCounter,
 	}
 	m.muxWriter = &MuxWriter{
 		f:               m.f,
@@ -327,7 +327,11 @@ func (m *Muxer) Serve(ctx context.Context) error {
 			m.explicitShutdown.Fuse(false)
 			m.r.Close()
 			m.abort()
-			ch <- err
+			// don't block if parent goroutine quit early
+			select {
+			case ch <- err:
+			default:
+			}
 		}()
 		select {
 		case err := <-ch:
@@ -344,7 +348,11 @@ func (m *Muxer) Serve(ctx context.Context) error {
 			m.explicitShutdown.Fuse(false)
 			m.w.Close()
 			m.abort()
-			ch <- err
+			// don't block if parent goroutine quit early
+			select {
+			case ch <- err:
+			default:
+			}
 		}()
 		select {
 		case err := <-ch:
@@ -358,7 +366,11 @@ func (m *Muxer) Serve(ctx context.Context) error {
 		ch := make(chan error)
 		go func() {
 			err := m.muxMetricsUpdater.run(m.config.Logger)
-			ch <- err
+			// don't block if parent goroutine quit early
+			select {
+			case ch <- err:
+			default:
+			}
 		}()
 		select {
 		case err := <-ch: