android: Add an automatic reconnect on errors

This way the connection will be attempted to be kept up even on "fatal"
errors like authentication failures.

src/frontends/android/app/src/main/java/org/strongswan/android/logic/VpnStateService.java

@@ -22,6 +22,8 @@ import android.os.Binder;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
+import android.os.Message;
+import android.os.SystemClock;
 
 import org.strongswan.android.R;
 import org.strongswan.android.data.VpnProfile;
@@ -29,6 +31,7 @@ import org.strongswan.android.data.VpnProfileDataSource;
 import org.strongswan.android.logic.imc.ImcState;
 import org.strongswan.android.logic.imc.RemediationInstruction;
 
+import java.lang.ref.WeakReference;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedList;
@@ -46,6 +49,10 @@ public class VpnStateService extends Service
 	private ErrorState mError = ErrorState.NO_ERROR;
 	private ImcState mImcState = ImcState.UNKNOWN;
 	private final LinkedList<RemediationInstruction> mRemediationInstructions = new LinkedList<RemediationInstruction>();
+	private static long RETRY_INTERVAL = 1000;
+	private static int RETRY_MSG = 1;
+	private long mRetryTimeout;
+	private long mRetryIn;
 
 	public enum State
 	{
@@ -93,7 +100,7 @@ public class VpnStateService extends Service
 	{
 		/* this handler allows us to notify listeners from the UI thread and
 		 * not from the threads that actually report any state changes */
-		mHandler = new Handler();
+		mHandler = new RetryHandler(this);
 	}
 
 	@Override
@@ -151,6 +158,24 @@ public class VpnStateService extends Service
 		return mConnectionID;
 	}
 
+	/**
+	 * Get the total number of seconds until there is an automatic retry to reconnect.
+	 * @return total number of seconds until the retry
+	 */
+	public int getRetryTimeout()
+	{
+		return (int)(mRetryTimeout / 1000);
+	}
+
+	/**
+	 * Get the number of seconds until there is an automatic retry to reconnect.
+	 * @return number of seconds until the retry
+	 */
+	public int getRetryIn()
+	{
+		return (int)(mRetryIn / 1000);
+	}
+
 	/**
 	 * Get the current state.
 	 *
@@ -231,6 +256,7 @@ public class VpnStateService extends Service
 	 */
 	public void disconnect()
 	{
+		resetRetryTimer();
 		/* as soon as the TUN device is created by calling establish() on the
 		 * VpnService.Builder object the system binds to the service and keeps
 		 * bound until the file descriptor of the TUN device is closed.  thus
@@ -310,6 +336,7 @@ public class VpnStateService extends Service
 			@Override
 			public Boolean call() throws Exception
 			{
+				resetRetryTimer();
 				VpnStateService.this.mConnectionID++;
 				VpnStateService.this.mProfile = profile;
 				VpnStateService.this.mState = State.CONNECTING;
@@ -359,6 +386,14 @@ public class VpnStateService extends Service
 			{
 				if (VpnStateService.this.mError != error)
 				{
+					if (VpnStateService.this.mError == ErrorState.NO_ERROR)
+					{
+						setRetryTimer(error);
+					}
+					else if (error == ErrorState.NO_ERROR)
+					{
+						resetRetryTimer();
+					}
 					VpnStateService.this.mError = error;
 					return true;
 				}
@@ -416,4 +451,92 @@ public class VpnStateService extends Service
 			}
 		});
 	}
+
+	/**
+	 * Sets the retry timer
+	 */
+	private void setRetryTimer(ErrorState error)
+	{
+		long timeout;
+
+		switch (error)
+		{
+			case AUTH_FAILED:
+				timeout = 20000;
+				break;
+			case PEER_AUTH_FAILED:
+				timeout = 20000;
+				break;
+			case LOOKUP_FAILED:
+				timeout = 10000;
+				break;
+			case UNREACHABLE:
+				timeout = 10000;
+				break;
+			case PASSWORD_MISSING:
+				/* this needs user intervention (entering the password) */
+				timeout = 0;
+				break;
+			case CERTIFICATE_UNAVAILABLE:
+				/* if this is because the device has to be unlocked we might be able to reconnect */
+				timeout = 10000;
+				break;
+			default:
+				timeout = 20000;
+				break;
+		}
+		mRetryTimeout = mRetryIn = timeout;
+		if (timeout <= 0)
+		{
+			return;
+		}
+		mHandler.sendMessageAtTime(mHandler.obtainMessage(RETRY_MSG), SystemClock.uptimeMillis() + RETRY_INTERVAL);
+	}
+
+	/**
+	 * Reset the retry timer
+	 */
+	private void resetRetryTimer()
+	{
+		mRetryTimeout = 0;
+		mRetryIn = 0;
+	}
+
+	/**
+	 * Special Handler subclass that handles the retry countdown (more accurate than CountDownTimer)
+	 */
+	private static class RetryHandler extends Handler {
+		WeakReference<VpnStateService> mService;
+
+		public RetryHandler(VpnStateService service)
+		{
+			mService = new WeakReference<>(service);
+		}
+
+		@Override
+		public void handleMessage(Message msg)
+		{
+			/* handle retry countdown */
+			if (mService.get().mRetryTimeout <= 0)
+			{
+				return;
+			}
+			mService.get().mRetryIn -= RETRY_INTERVAL;
+			if (mService.get().mRetryIn > 0)
+			{
+				/* calculate next interval before notifying listeners */
+				long next = SystemClock.uptimeMillis() + RETRY_INTERVAL;
+
+				for (VpnStateListener listener : mService.get().mListeners)
+				{
+					listener.stateChanged();
+				}
+				sendMessageAtTime(obtainMessage(RETRY_MSG), next);
+			}
+			else
+			{
+				mService.get().reconnect();
+			}
+		}
+	}
 }

src/frontends/android/app/src/main/java/org/strongswan/android/ui/VpnStateFragment.java

@@ -41,11 +41,6 @@ import org.strongswan.android.logic.VpnStateService;
 import org.strongswan.android.logic.VpnStateService.ErrorState;
 import org.strongswan.android.logic.VpnStateService.State;
 import org.strongswan.android.logic.VpnStateService.VpnStateListener;
-import org.strongswan.android.logic.imc.ImcState;
-import org.strongswan.android.logic.imc.RemediationInstruction;
-
-import java.util.ArrayList;
-import java.util.List;
 
 public class VpnStateFragment extends Fragment implements VpnStateListener
 {
@@ -62,7 +57,7 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 	private LinearLayout mErrorView;
 	private TextView mErrorText;
 	private Button mErrorRetry;
-	private Button mDismissError;
+	private Button mShowLog;
 	private long mErrorConnectionID;
 	private VpnStateService mService;
 	private final ServiceConnection mServiceConnection = new ServiceConnection()
@@ -128,12 +123,13 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 		View view = inflater.inflate(R.layout.vpn_state_fragment, null);
 
 		mActionButton = (Button)view.findViewById(R.id.action);
+		mActionButton.setOnClickListener(v -> clearError());
 		enableActionButton(null);
 
 		mErrorView = view.findViewById(R.id.vpn_error);
 		mErrorText = view.findViewById(R.id.vpn_error_text);
 		mErrorRetry = view.findViewById(R.id.retry);
-		mDismissError = view.findViewById(R.id.dismiss_error);
+		mShowLog = view.findViewById(R.id.show_log);
 		mProgress = (ProgressBar)view.findViewById(R.id.progress);
 		mStateView = (TextView)view.findViewById(R.id.vpn_state);
 		mColorStateBase = mStateView.getCurrentTextColor();
@@ -146,7 +142,10 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 				mService.reconnect();
 			}
 		});
-		mDismissError.setOnClickListener(v -> clearError());
+		mShowLog.setOnClickListener(v -> {
+			Intent intent = new Intent(getActivity(), LogActivity.class);
+			startActivity(intent);
+		});
 
 		return view;
 	}
@@ -194,7 +193,6 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 		VpnProfile profile = mService.getProfile();
 		State state = mService.getState();
 		ErrorState error = mService.getErrorState();
-		ImcState imcState = mService.getImcState();
 		String name = "";
 
 		if (getActivity() == null)
@@ -207,12 +205,13 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 			name = profile.getName();
 		}
 
-		if (reportError(connectionID, name, error, imcState))
+		if (reportError(connectionID, name, error))
 		{
 			return;
 		}
 
 		mProfileNameView.setText(name);
+		mProgress.setIndeterminate(true);
 
 		switch (state)
 		{
@@ -247,7 +246,7 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 		}
 	}
 
-	private boolean reportError(long connectionID, String name, ErrorState error, ImcState imcState)
+	private boolean reportError(long connectionID, String name, ErrorState error)
 	{
 		if (error == ErrorState.NO_ERROR)
 		{
@@ -257,15 +256,26 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 		mErrorConnectionID = connectionID;
 		mProfileNameView.setText(name);
 		showProfile(true);
-		mProgress.setVisibility(View.GONE);
 		mStateView.setText(R.string.state_error);
 		mStateView.setTextColor(mColorStateError);
-		enableActionButton(getString(R.string.show_log));
+		enableActionButton(getString(android.R.string.cancel));
-		mActionButton.setOnClickListener(v -> {
+
-			Intent intent = new Intent(getActivity(), LogActivity.class);
+		int retry = mService.getRetryIn();
-			startActivity(intent);
+		if (retry > 0)
-		});
+		{
-		mErrorText.setText(getString(R.string.error_format, getString(mService.getErrorText())));
+			mProgress.setIndeterminate(false);
+			mProgress.setMax(mService.getRetryTimeout());
+			mProgress.setProgress(retry);
+			mProgress.setVisibility(View.VISIBLE);
+			mStateView.setText(getResources().getQuantityString(R.plurals.retry_in, retry, retry));
+		}
+		else if (mService.getRetryTimeout() <= 0)
+		{
+			mProgress.setVisibility(View.GONE);
+		}
+
+		String text = getString(R.string.error_format, getString(mService.getErrorText()));
+		mErrorText.setText(text);
 		mErrorView.setVisibility(View.VISIBLE);
 		return true;
 	}
@@ -281,19 +291,17 @@ public class VpnStateFragment extends Fragment implements VpnStateListener
 		mActionButton.setText(text);
 		mActionButton.setEnabled(text != null);
 		mActionButton.setVisibility(text != null ? View.VISIBLE : View.GONE);
-		mActionButton.setOnClickListener(mDisconnectListener);
 	}
 
 	private void clearError()
 	{
 		if (mService != null)
 		{
+			mService.disconnect();
 			if (mService.getConnectionID() == mErrorConnectionID)
 			{
-				mService.disconnect();
 				mService.setError(ErrorState.NO_ERROR);
 			}
 		}
-		updateView();
 	}
 }

src/frontends/android/app/src/main/res/layout/vpn_state_fragment.xml

@@ -34,6 +34,7 @@
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_marginLeft="20dp"
+            android:layout_marginRight="20dp"
             android:layout_marginTop="24dp"
             android:layout_marginBottom="12dp"
             android:text="Failed to establish VPN: Server is unreachable"
@@ -48,11 +49,11 @@
             android:gravity="end" >
 
             <Button
-                android:id="@+id/dismiss_error"
+                android:id="@+id/show_log"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_marginLeft="8dp"
-                android:text="@string/dismiss"
+                android:text="@string/show_log"
                 android:textColor="@color/primary"
                 android:textSize="14sp"
                 android:textStyle="bold"

src/frontends/android/app/src/main/res/values-de/strings.xml

@@ -198,6 +198,11 @@
     <string name="disconnect_active_connection">Dies trennt die aktuelle VPN Verbindung!</string>
     <string name="connect">Verbinden</string>
     <string name="retry">Wiederholen</string>
+    <plurals name="retry_in">
+        <item quantity="one">Wiederholen in %1$d Sekunde</item>
+        <item quantity="other">Wiederholen in %1$d Sekunden</item>
+    </plurals>
+    <string name="cancel_retry">Wiederholen abbrechen</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">VPN umschalten</string>

src/frontends/android/app/src/main/res/values-pl/strings.xml

@@ -198,6 +198,11 @@
     <string name="disconnect_active_connection">This will disconnect the active VPN connection!</string>
     <string name="connect">Połącz</string>
     <string name="retry">Retry</string>
+    <plurals name="retry_in">
+        <item quantity="one">Retry in %1$d second</item>
+        <item quantity="other">Retry in %1$d seconds</item>
+    </plurals>
+    <string name="cancel_retry">Cancel retry</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">Toggle VPN</string>

src/frontends/android/app/src/main/res/values-ru/strings.xml

@@ -195,6 +195,11 @@
     <string name="disconnect_active_connection">This will disconnect the active VPN connection!</string>
     <string name="connect">Соединить</string>
     <string name="retry">Retry</string>
+    <plurals name="retry_in">
+        <item quantity="one">Retry in %1$d second</item>
+        <item quantity="other">Retry in %1$d seconds</item>
+    </plurals>
+    <string name="cancel_retry">Cancel retry</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">Toggle VPN</string>

src/frontends/android/app/src/main/res/values-ua/strings.xml

@@ -196,6 +196,11 @@
     <string name="disconnect_active_connection">This will disconnect the active VPN connection!</string>
     <string name="connect">Підключити</string>
     <string name="retry">Retry</string>
+    <plurals name="retry_in">
+        <item quantity="one">Retry in %1$d second</item>
+        <item quantity="other">Retry in %1$d seconds</item>
+    </plurals>
+    <string name="cancel_retry">Cancel retry</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">Toggle VPN</string>

src/frontends/android/app/src/main/res/values-zh-rCN/strings.xml

@@ -195,6 +195,11 @@
     <string name="disconnect_active_connection">This will disconnect the active VPN connection!</string>
     <string name="connect">连接</string>
     <string name="retry">Retry</string>
+    <plurals name="retry_in">
+        <item quantity="one">Retry in %1$d second</item>
+        <item quantity="other">Retry in %1$d seconds</item>
+    </plurals>
+    <string name="cancel_retry">Cancel retry</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">Toggle VPN</string>

src/frontends/android/app/src/main/res/values-zh-rTW/strings.xml

@@ -195,6 +195,11 @@
     <string name="disconnect_active_connection">This will disconnect the active VPN connection!</string>
     <string name="connect">連線</string>
     <string name="retry">Retry</string>
+    <plurals name="retry_in">
+        <item quantity="one">Retry in %1$d second</item>
+        <item quantity="other">Retry in %1$d seconds</item>
+    </plurals>
+    <string name="cancel_retry">Cancel retry</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">Toggle VPN</string>

src/frontends/android/app/src/main/res/values/strings.xml

@@ -198,6 +198,11 @@
     <string name="disconnect_active_connection">This will disconnect the active VPN connection!</string>
     <string name="connect">Connect</string>
     <string name="retry">Retry</string>
+    <plurals name="retry_in">
+        <item quantity="one">Retry in %1$d second</item>
+        <item quantity="other">Retry in %1$d seconds</item>
+    </plurals>
+    <string name="cancel_retry">Cancel retry</string>
 
     <!-- Quick Settings tile -->
     <string name="tile_default">Toggle VPN</string>