From 8fe897a3c7654ee0573bfb50333ebc3a319cf3f8 Mon Sep 17 00:00:00 2001
From: Arne Schwabe <arne@rfc2549.org>
Date: Thu, 1 Jun 2023 00:28:41 +0200
Subject: Use JobScheduler as backup to keep an active VPN active

This should restart it in some instances when the app dies or gets killed.
---
 main/src/main/AndroidManifest.xml                  |   5 +
 .../de/blinkt/openvpn/core/OpenVPNService.java     |   9 +-
 .../java/de/blinkt/openvpn/core/keepVPNAlive.java  | 106 +++++++++++++++++++++
 3 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100644 main/src/main/java/de/blinkt/openvpn/core/keepVPNAlive.java

diff --git a/main/src/main/AndroidManifest.xml b/main/src/main/AndroidManifest.xml
index 4a8348e1..50362b30 100644
--- a/main/src/main/AndroidManifest.xml
+++ b/main/src/main/AndroidManifest.xml
@@ -96,6 +96,11 @@
             </intent-filter>
         </receiver>
 
+        <service android:name=".core.keepVPNAlive"
+                android:process=":openvpn"
+                android:exported="true"
+                android:permission="android.permission.BIND_JOB_SERVICE"/>
+
 
         <activity
             android:name=".LaunchVPN"
diff --git a/main/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java b/main/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
index 115d6319..9e42378b 100644
--- a/main/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
+++ b/main/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
@@ -14,6 +14,8 @@ import android.app.Notification;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.app.UiModeManager;
+import android.app.job.JobInfo;
+import android.app.job.JobScheduler;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
@@ -34,12 +36,12 @@ import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.Message;
 import android.os.ParcelFileDescriptor;
+import android.os.PersistableBundle;
 import android.os.RemoteException;
 import android.system.OsConstants;
 import android.text.TextUtils;
 import android.util.Base64;
 import android.util.Log;
-import android.util.Pair;
 import android.widget.Toast;
 
 import androidx.annotation.NonNull;
@@ -227,6 +229,10 @@ public class OpenVPNService extends VpnService implements StateListener, Callbac
     }
 
     private void endVpnService() {
+        if (!isAlwaysOn()) {
+            /* if we should be an always on VPN, keep the timer running */
+            keepVPNAlive.unscheduleKeepVPNAliveJobService(this);
+        }
         synchronized (mProcessLock) {
             mProcessThread = null;
         }
@@ -573,6 +579,7 @@ public class OpenVPNService extends VpnService implements StateListener, Callbac
 
         ProfileManager.setConnectedVpnProfile(this, mProfile);
         VpnStatus.setConnectedVPNProfile(mProfile.getUUIDString());
+        keepVPNAlive.scheduleKeepVPNAliveJobService(this, vp);
 
         String nativeLibraryDirectory = getApplicationInfo().nativeLibraryDir;
         String tmpDir;
diff --git a/main/src/main/java/de/blinkt/openvpn/core/keepVPNAlive.java b/main/src/main/java/de/blinkt/openvpn/core/keepVPNAlive.java
new file mode 100644
index 00000000..2b75b2fe
--- /dev/null
+++ b/main/src/main/java/de/blinkt/openvpn/core/keepVPNAlive.java
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2012-2023 Arne Schwabe
+ * Distributed under the GNU GPL v2 with additional terms. For full terms see the file doc/LICENSE.txt
+ */
+
+package de.blinkt.openvpn.core;
+
+import android.app.job.JobInfo;
+import android.app.job.JobParameters;
+import android.app.job.JobScheduler;
+import android.app.job.JobService;
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.net.VpnService;
+import android.os.PersistableBundle;
+
+import de.blinkt.openvpn.LaunchVPN;
+import de.blinkt.openvpn.VpnProfile;
+
+/**
+ * This is a task that is run periodically to restart the VPN if tit has died for
+ * some reason in the background
+ */
+public class keepVPNAlive extends JobService implements VpnStatus.StateListener {
+    private ConnectionStatus mLevel = ConnectionStatus.UNKNOWN_LEVEL;
+    private static final int JOBID_KEEPVPNALIVE = 6231;
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        VpnStatus.addStateListener(this);
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        VpnStatus.removeStateListener(this);
+    }
+
+    @Override
+    public boolean onStartJob(JobParameters jobParameters) {
+        if (mLevel == ConnectionStatus.UNKNOWN_LEVEL || mLevel == ConnectionStatus.LEVEL_NOTCONNECTED) {
+            String vpnUUID = jobParameters.getExtras().getString(LaunchVPN.EXTRA_KEY);
+            VpnProfile vp = ProfileManager.get(this, vpnUUID);
+            if (vp == null) {
+                VpnStatus.logError("Keepalive service cannot find VPN");
+                unscheduleKeepVPNAliveJobService(this);
+                return false;
+            }
+            VPNLaunchHelper.startOpenVpn(vp, getApplicationContext(), "VPN keep alive Job");
+        } else {
+            VpnStatus.logDebug("Keepalive service called but VPN still connected.");
+        }
+
+        /* The job has finished */
+        return false;
+    }
+
+    @Override
+    public boolean onStopJob(JobParameters jobParameters) {
+        /* not doing anything */
+        return true;
+    }
+
+    @Override
+    public void updateState(String state, String logmessage,
+                            int localizedResId, ConnectionStatus level, Intent Intent) {
+        mLevel = level;
+    }
+
+    @Override
+    public void setConnectedVPN(String uuid) {
+
+    }
+
+    public static void scheduleKeepVPNAliveJobService(Context c, VpnProfile vp) {
+        ComponentName keepVPNAliveComponent = new ComponentName(c, keepVPNAlive.class);
+        JobInfo.Builder jib = new JobInfo.Builder(JOBID_KEEPVPNALIVE, keepVPNAliveComponent);
+
+        /* set the VPN that should be restarted if we get killed */
+        PersistableBundle extraBundle = new PersistableBundle();
+        extraBundle.putString(de.blinkt.openvpn.LaunchVPN.EXTRA_KEY, vp.getUUIDString());
+        jib.setExtras(extraBundle);
+
+        /* periodic timing */
+        /* The current limits are 15 minutes and 5 minutes for flex and periodic timer
+         * but we use a minimum of 5 minutes and 2 minutes to avoid problems if there is some
+         * strange Android build that allows lower lmits.
+         */
+        long initervalMillis = Math.max(JobInfo.getMinPeriodMillis(), 5 * 60 * 1000L);
+        long flexMillis = Math.max(JobInfo.getMinFlexMillis(), 2 * 60 * 1000L);
+        jib.setPeriodic(initervalMillis, flexMillis);
+        jib.setPersisted(true);
+
+        JobScheduler jobScheduler = c.getSystemService(JobScheduler.class);
+        jobScheduler.schedule(jib.build());
+        VpnStatus.logDebug("Scheduling VPN keep alive for VPN " + vp.mName);
+    }
+
+    public static void unscheduleKeepVPNAliveJobService(Context c) {
+        JobScheduler jobScheduler = c.getSystemService(JobScheduler.class);
+        jobScheduler.cancel(JOBID_KEEPVPNALIVE);
+        VpnStatus.logDebug("Unscheduling VPN keep alive");
+    }
+}
-- 
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