android: routing - package scans off the main thread, no needless reconnects

- computeExcludedPackages() (full PackageManager scan) runs on Default,
  not Main.immediate, on config changes and package add/remove
- updateConfig() ignores no-op transforms and reconnects when routing is
  switched off too (direct apps kept bypassing the tunnel until then)
- config is volatile and read after its version, so an old config can no
  longer be cached under a new version
- Direct apps loads the app list once per entry, without GET_META_DATA

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/frontends/android/app/src/main/java/org/strongswan/android/logic/routing/RoutingManager.kt

@@ -116,6 +116,8 @@ class RoutingManager private constructor(private val context: Context)
 	private val handler = Handler(Looper.getMainLooper())
 	private val prefs = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE)
 	private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Main.immediate)
+	/* read from the charon and IO threads in computeExcludedPackages() */
+	@Volatile
 	private var config = RoutingConfig()
 	private var service: VpnStateService? = null
 	private var migratedOnlyProfiles = 0
@@ -158,7 +160,8 @@ class RoutingManager private constructor(private val context: Context)
 		override fun onReceive(context: Context?, intent: Intent?)
 		{
 			invalidateCache()
-			scope.launch { computeExcludedPackages() }
+			/* a full PackageManager scan: never on the main thread */
+			scope.launch(Dispatchers.Default) { computeExcludedPackages() }
 		}
 	}
 
@@ -183,13 +186,23 @@ class RoutingManager private constructor(private val context: Context)
 
 	fun updateConfig(transform: (RoutingConfig) -> RoutingConfig)
 	{
-		config = transform(config)
-		saveConfig(config)
+		val previous = config
+		val updated = transform(previous)
+		if (updated == previous)
+		{	/* e.g. a chip tapped that is already in that state: no reconnect */
+			return
+		}
+		config = updated
+		saveConfig(updated)
 		invalidateCache()
 		publish()
-		if (config.enabled)
-		{	/* warm the package cache so the connect path stays fast */
-			scope.launch { computeExcludedPackages() }
+		if (updated.enabled)
+		{	/* warm the package cache (off the main thread) so the connect path stays fast */
+			scope.launch(Dispatchers.Default) { computeExcludedPackages() }
+		}
+		if (updated.enabled || previous.enabled)
+		{	/* also when routing was just switched off: the excluded apps keep
+			 * bypassing the tunnel until it is re-established */
 			scheduleReconnect()
 		}
 	}
@@ -384,12 +397,15 @@ class RoutingManager private constructor(private val context: Context)
 	 */
 	fun computeExcludedPackages(): Set<String>
 	{
+		/* version before config: updateConfig() writes config first, so this
+		 * order can at worst cache a newer config under an older version
+		 * (recomputed next time), never an old config under the new one */
+		val version = configVersion
 		val current = config
 		if (!current.enabled)
 		{
 			return emptySet()
 		}
-		val version = configVersion
 		packageCache?.let { (cachedVersion, packages) ->
 			if (cachedVersion == version)
 			{
@@ -624,7 +640,7 @@ class RoutingManager private constructor(private val context: Context)
 		/** All installed apps that hold the INTERNET permission. */
 		fun loadInternetPackages(pm: PackageManager): Set<String> = try
 		{
-			pm.getInstalledApplications(PackageManager.GET_META_DATA)
+			pm.getInstalledApplications(0)
 				.asSequence()
 				.filter { pm.checkPermission(android.Manifest.permission.INTERNET, it.packageName) == PackageManager.PERMISSION_GRANTED }
 				.map { it.packageName }

src/frontends/android/app/src/main/java/org/strongswan/android/ui/compose/routing/DirectAppsScreen.kt

@@ -74,6 +74,8 @@ import org.strongswan.android.ui.compose.theme.ShxSpacing
 fun DirectAppsScreen(onBack: () -> Unit, viewModel: DirectAppsViewModel = viewModel())
 {
 	val state by viewModel.ui.collectAsStateWithLifecycle()
+	/* the only load trigger (also re-entering the screen with a retained
+	 * view model picks up newly installed apps) */
 	androidx.compose.runtime.LaunchedEffect(Unit) { viewModel.refresh() }
 	DirectAppsContent(
 		state = state,

src/frontends/android/app/src/main/java/org/strongswan/android/ui/compose/routing/DirectAppsViewModel.kt

@@ -114,11 +114,6 @@ class DirectAppsViewModel(app: Application) : AndroidViewModel(app)
 		.flowOn(Dispatchers.Default)
 		.stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), DirectAppsUiState())
 
-	init
-	{
-		refresh()
-	}
-
 	/** (Re)loads the installed apps; the previous list stays visible meanwhile. */
 	fun refresh()
 	{
@@ -156,7 +151,7 @@ object DirectApps
 	fun loadInstalledApps(pm: PackageManager, ownPackage: String): List<InstalledApp>
 	{
 		val collator = Collator.getInstance()
-		return pm.getInstalledApplications(PackageManager.GET_META_DATA)
+		return pm.getInstalledApplications(0)
 			.asSequence()
 			.filter { it.packageName != ownPackage }
 			.filter { pm.checkPermission(android.Manifest.permission.INTERNET, it.packageName) == PackageManager.PERMISSION_GRANTED }