Prevent connecting loops when using connect intent more than once (#95)

* startvpnworker.java: prevent connecting loops

If start intent called more than once.

Turns out there were still some cases where the bug would occur, also it turns out checking the status of a VPN connection isn't foolproof in android, so this is a safer way to fix it, we just ensure that the autoConnect var is set to false when disconnecting.

Fixes: https://github.com/tailscale/tailscale/issues/8013

Signed-off-by: Brett Jenkins <brett@brettjenkins.co.uk>

android/src/main/java/com/tailscale/ipn/App.java

@@ -106,9 +106,6 @@ public class App extends Application {
 				NetworkInfo active = cMgr.getActiveNetworkInfo();
 				// https://developer.android.com/training/monitoring-device-state/connectivity-status-type
 				boolean isConnected = active != null && active.isConnectedOrConnecting();
-				if (isConnected) {
-					((App)getApplicationContext()).autoConnect = false;
-				}
 				onConnectivityChanged(isConnected);
 			}
 

android/src/main/java/com/tailscale/ipn/IPNService.java

@@ -22,6 +22,7 @@ public class IPNService extends VpnService {
 
 	@Override public int onStartCommand(Intent intent, int flags, int startId) {
 		if (intent != null && ACTION_DISCONNECT.equals(intent.getAction())) {
+			((App)getApplicationContext()).autoConnect = false;
 			close();
 			return START_NOT_STICKY;
 		}

android/src/main/java/com/tailscale/ipn/StartVPNWorker.java

@@ -4,16 +4,16 @@
 
 package com.tailscale.ipn;
 
-import androidx.work.Worker;
-import android.content.Context;
-import androidx.work.WorkerParameters;
-import android.net.VpnService;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
+import android.content.Context;
 import android.content.Intent;
+import android.net.VpnService;
 import android.os.Build;
+import androidx.work.Worker;
+import androidx.work.WorkerParameters;
 
 public final class StartVPNWorker extends Worker {
 
@@ -24,8 +24,9 @@ public final class StartVPNWorker extends Worker {
     }
 
     @Override public Result doWork() {
-        // We will start the VPN from the background
         App app = ((App)getApplicationContext());
+
+        // We will start the VPN from the background
         app.autoConnect = true;
         // We need to make sure we prepare the VPN Service, just in case it isn't prepared.