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.

origin/tunnel.go

@@ -322,7 +322,10 @@ func ServeTunnel(
 			select {
 			case <-serveCtx.Done():
 				// UnregisterTunnel blocks until the RPC call returns
-				err := UnregisterTunnel(handler.muxer, config.GracePeriod, config.TransportLogger)
+				var err error
+				if connectedFuse.Value() {
+					err = UnregisterTunnel(handler.muxer, config.GracePeriod, config.TransportLogger)
+				}
 				handler.muxer.Shutdown()
 				return err
 			case <-updateMetricsTickC:
@@ -519,6 +522,8 @@ func UnregisterTunnel(muxer *h2mux.Muxer, gracePeriod time.Duration, logger *log
 		// RPC stream open error
 		return err
 	}
+	defer tunnelServer.Close()
+
 	// gracePeriod is encoded in int64 using capnproto
 	return tunnelServer.UnregisterTunnel(ctx, gracePeriod.Nanoseconds())
 }