Enhanced monitoring for changes or removal of the V2Ray route, restor…

…ing it if necessary.

ivpn/desktop-app-shadow#146

daemon/netchange/net_change_detector.go

@@ -106,11 +106,14 @@ func (d *Detector) DelayBeforeNotify() time.Duration {
 	return d.delayBeforeNotify
 }
 
-// must be called when routing change detected (called from platform-specific sources)
+// Must be called when routing change detected (called from platform-specific sources)
+// It notifies about routing change with delay 'd.DelayBeforeNotify()'. This reduces amount of multiple consecutive notifications
 func (d *Detector) routingChangeDetected() {
 	d.timerNotifyAfterDelay.Reset(d.DelayBeforeNotify())
 }
 
+// Immediately notify about routing change.
+// Consider using routingChangeDetected() instead
 func (d *Detector) notifyRoutingChange() {
 	if d.routingChangeNotifyChan == nil {
 		return

daemon/netchange/net_change_detector_windows.go

@@ -116,7 +116,7 @@ func (d *Detector) doStart() {
 		}
 
 		// notify about routing change
-		d.notifyRoutingChange()
+		d.routingChangeDetected()
 	}
 }
 

daemon/v2r/v2ray.go

@@ -75,6 +75,7 @@ type V2RayWrapper struct {
 	mutex          sync.Mutex
 	stoppedChan    chan struct{}
 
+	routeStatusMutex sync.Mutex
 	// IP address of the default gateway which was used for static route to V2Ray server
 	defaultGeteway net.IP
 	// IP address of local interface which is in use for communication with V2Ray server
@@ -160,21 +161,37 @@ func (v *V2RayWrapper) UpdateMainRoute() error {
 	v.mutex.Lock()
 	defer v.mutex.Unlock()
 
+	var curDefaultGeteway net.IP
+	var curLocalInterfaceIp net.IP
+	func() {
+		// lock access to defaultGeteway and localInterfaceIp
+		v.routeStatusMutex.Lock()
+		defer v.routeStatusMutex.Unlock()
+		curDefaultGeteway = v.defaultGeteway
+		curLocalInterfaceIp = v.localInterfaceIp
+	}()
+
 	// check: do we need to update route to V2Ray server? (due to it was changed or removed)
 	isRouteChanged := false
-	if lInterfaceIp, err := v.getMainRouteLocalInfAddress(); err == nil {
-		if v.localInterfaceIp != nil && !v.localInterfaceIp.Equal(lInterfaceIp) {
-			isRouteChanged = true
+	if curLocalInterfaceIp != nil {
+		if lInterfaceIp, err := v.getMainRouteLocalInfAddress(); err == nil {
+			if !curLocalInterfaceIp.Equal(lInterfaceIp) {
+				isRouteChanged = true
+			}
 		}
 	}
 
+	if !isRouteChanged && curDefaultGeteway == nil {
+		return nil
+	}
+
 	// check: do we need to update route to V2Ray server? (due to change of default gateway)
 	isGatewayChanged := false
 	gwIp, err := netinfo.DefaultGatewayIP()
 	if err != nil {
-		return fmt.Errorf("getting default gateway ip error : %w", err)
+		return fmt.Errorf("failed to check V2Ray route consistency: %w", err)
 	}
-	if v.defaultGeteway != nil && !v.defaultGeteway.Equal(gwIp) {
+	if !curDefaultGeteway.Equal(gwIp) {
 		isGatewayChanged = true
 	}
 
@@ -198,6 +215,10 @@ func (v *V2RayWrapper) setMainRoute(defaultGateway net.IP) error {
 		}
 	}
 	if err := v.implSetMainRoute(defaultGateway); err == nil {
+		// lock access to defaultGeteway and localInterfaceIp
+		v.routeStatusMutex.Lock()
+		defer v.routeStatusMutex.Unlock()
+
 		v.defaultGeteway = defaultGateway
 		// save IP address of local interface which is in use for communication with V2Ray server
 		v.localInterfaceIp, err = v.getMainRouteLocalInfAddress()
@@ -208,18 +229,14 @@ func (v *V2RayWrapper) setMainRoute(defaultGateway net.IP) error {
 	return err
 }
 
-// Get IP address of local interface which is in use for communication with V2Ray server
-// (it depends of routing table)
-func (v *V2RayWrapper) getMainRouteLocalInfAddress() (net.IP, error) {
-	remoteHost, _, err := v.getRemoteEndpoint()
-	if err != nil {
-		return nil, err
-	}
-	return netinfo.GetOutboundIPEx(remoteHost)
-}
-
 func (v *V2RayWrapper) deleteMainRoute() error {
-	v.defaultGeteway = nil
+	func() {
+		// lock access to defaultGeteway and localInterfaceIp
+		v.routeStatusMutex.Lock()
+		defer v.routeStatusMutex.Unlock()
+		v.defaultGeteway = nil
+		v.localInterfaceIp = nil
+	}()
 	return v.implDeleteMainRoute()
 }
 
@@ -354,8 +371,29 @@ func (v *V2RayWrapper) start() (retError error) {
 		return startError
 	}
 
-	// log when process finished
+	// routine alive until process finished
 	go func() {
+
+		// Periodically checking the IP address of the local interface used for communication with the V2Ray server
+		// and update/restore route, if necessary
+		done := make(chan struct{}, 1)
+		defer close(done)
+		go func() {
+			for {
+				select {
+				case <-time.After(time.Second * 20):
+					if v.isMainRouteLocalInfAddressChanged() {
+						log.Info("The IP address of the local interface used for communication with the V2Ray server has changed")
+						if err := v.UpdateMainRoute(); err != nil {
+							log.Error(err)
+						}
+					}
+				case <-done:
+					return
+				}
+			}
+		}()
+
 		v.command.Wait()
 		// ensure route is deleted
 		v.implDeleteMainRoute()
@@ -365,3 +403,35 @@ func (v *V2RayWrapper) start() (retError error) {
 	log.Info(fmt.Sprintf("V2Ray client started (port %s)", configuredPortStr))
 	return nil
 }
+
+func (v *V2RayWrapper) isMainRouteLocalInfAddressChanged() bool {
+	var curLocalInterfaceIp net.IP
+	func() {
+		// lock access to defaultGeteway and localInterfaceIp
+		v.routeStatusMutex.Lock()
+		defer v.routeStatusMutex.Unlock()
+		curLocalInterfaceIp = v.localInterfaceIp
+	}()
+
+	if curLocalInterfaceIp == nil {
+		return false
+	}
+
+	// check: do we need to update route to V2Ray server? (due to it was changed or removed)
+	if lInterfaceIp, err := v.getMainRouteLocalInfAddress(); err == nil {
+		if !curLocalInterfaceIp.Equal(lInterfaceIp) {
+			return true
+		}
+	}
+	return false
+}
+
+// Get IP address of local interface which is in use for communication with V2Ray server
+// (it depends of routing table)
+func (v *V2RayWrapper) getMainRouteLocalInfAddress() (net.IP, error) {
+	remoteHost, _, err := v.getRemoteEndpoint()
+	if err != nil {
+		return nil, err
+	}
+	return netinfo.GetOutboundIPEx(remoteHost)
+}