fix: improve always on vpn reliability

#1289

app/src/main/java/com/zaneschepke/wireguardautotunnel/WireGuardAutoTunnel.kt

@@ -51,6 +51,13 @@ class WireGuardAutoTunnel : Application(), KoinComponent {
 
     private val backend: Backend by inject()
 
+    private val alwaysOnCallback =
+        object : VpnService.AlwaysOnCallback {
+            override fun alwaysOnTriggered() {
+                applicationScope.launch { tunnelCoordinator.startDefault() }
+            }
+        }
+
     @OptIn(KoinViewModelScopeApi::class)
     override fun onCreate() {
         super.onCreate()
@@ -86,13 +93,7 @@ class WireGuardAutoTunnel : Application(), KoinComponent {
             Timber.plant(ReleaseTree())
         }
 
-        backend.setAlwaysOnCallback(
-            object : VpnService.AlwaysOnCallback {
-                override fun alwaysOnTriggered() {
-                    applicationScope.launch { tunnelCoordinator.startDefault() }
-                }
-            }
-        )
+        backend.setAlwaysOnCallback(alwaysOnCallback)
 
         val dispatcher = get<TunnelEventDispatcher>()
         val coordinator = get<TunnelCoordinator>()

tunnel/src/main/java/com/zaneschepke/tunnel/backend/TunnelBackend.kt

@@ -25,7 +25,6 @@ import com.zaneschepke.tunnel.util.RootShellException
 import com.zaneschepke.tunnel.util.buildResolvedPeers
 import com.zaneschepke.tunnel.util.toHostMap
 import com.zaneschepke.wireguardautotunnel.parser.ActiveConfig
-import java.lang.ref.WeakReference
 import java.util.concurrent.ConcurrentHashMap
 import kotlin.time.Duration.Companion.milliseconds
 import kotlin.time.Duration.Companion.seconds
@@ -250,7 +249,7 @@ class TunnelBackend(
     }
 
     override fun setAlwaysOnCallback(alwaysOnCallback: VpnService.AlwaysOnCallback) {
-        ServiceHolder.alwaysOnCallback = WeakReference(alwaysOnCallback)
+        ServiceHolder.alwaysOnCallback = alwaysOnCallback
     }
 
     override suspend fun stop(id: Int): Result<Unit> = tunnelMutex.withLock {

tunnel/src/main/java/com/zaneschepke/tunnel/service/ServiceHolder.kt

@@ -4,7 +4,6 @@ import android.content.Context
 import android.content.Intent
 import com.zaneschepke.tunnel.ProxyBackend
 import com.zaneschepke.tunnel.util.BackendException
-import java.lang.ref.WeakReference
 import kotlin.time.Duration.Companion.milliseconds
 import kotlinx.coroutines.TimeoutCancellationException
 import kotlinx.coroutines.delay
@@ -90,7 +89,7 @@ internal class ServiceHolder(val context: Context) {
             service.shutdown()
             withTimeoutOrNull(1_500L.milliseconds) { tunnelServiceFlow.first { it == null } }
         } finally {
-            clearVpnService()
+            clearTunnelService()
         }
     }
 
@@ -110,6 +109,6 @@ internal class ServiceHolder(val context: Context) {
         const val SPECIAL_USE_SERVICE_TYPE_ID = 1 shl 30
         const val DEFAULT_MTU = 1280
         // for consumer to set AOVPN callback
-        var alwaysOnCallback: WeakReference<VpnService.AlwaysOnCallback>? = null
+        var alwaysOnCallback: VpnService.AlwaysOnCallback? = null
     }
 }

tunnel/src/main/java/com/zaneschepke/tunnel/service/TunnelService.kt

@@ -51,7 +51,7 @@ class TunnelService : LifecycleService() {
                 (intent.component!!.packageName != packageName)
         ) {
             Timber.d("TunnelService started by system")
-            alwaysOnCallback?.get()?.alwaysOnTriggered()
+            alwaysOnCallback?.alwaysOnTriggered()
         }
 
         return START_STICKY

tunnel/src/main/java/com/zaneschepke/tunnel/service/VpnService.kt

@@ -1,5 +1,6 @@
 package com.zaneschepke.tunnel.service
 
+import android.content.Context
 import android.content.Intent
 import android.net.TrafficStats
 import android.os.Build
@@ -81,15 +82,28 @@ class VpnService : android.net.VpnService(), KillSwitch, SocketProtector {
 
         bootKeepaliveService()
 
-        // Service restarted by system or Always-on VPN started
-        if (
-            intent == null ||
-                intent.component == null ||
-                (intent.component!!.packageName != packageName)
-        ) {
-            Timber.d("VpnService started by system (Always-On trigger)")
-            alwaysOnCallback?.get()?.alwaysOnTriggered()
+        // system recovery restart
+        if (intent == null) {
+            return START_STICKY
         }
+
+        val isUserLaunch = intent.getBooleanExtra(getUserLaunchExtraKey(this), false)
+
+        val platformSaysAlwaysOn =
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                isAlwaysOn
+            } else {
+                false
+            }
+
+        val isAlwaysOnTrigger =
+            !isUserLaunch && (intent.action == SERVICE_INTERFACE || platformSaysAlwaysOn)
+
+        if (isAlwaysOnTrigger) {
+            Timber.d("VpnService started by system (Always-On trigger)")
+            alwaysOnCallback?.alwaysOnTriggered()
+        }
+
         return START_STICKY
     }
 
@@ -330,6 +344,21 @@ class VpnService : android.net.VpnService(), KillSwitch, SocketProtector {
     }
 
     companion object {
+
+        private fun getUserLaunchExtraKey(context: Context): String {
+            return "${context.packageName}.EXTRA_IS_USER_LAUNCH"
+        }
+
+        @JvmStatic
+        fun start(context: Context, serviceClass: Class<out VpnService>) {
+            val intent =
+                Intent(context, serviceClass).apply {
+                    action = SERVICE_INTERFACE
+                    putExtra(getUserLaunchExtraKey(context), true)
+                }
+            context.startService(intent)
+        }
+
         private const val LOCKDOWN_SESSION_NAME = "Lockdown"
         private const val LOCALHOST = "127.0.0.1"
         private const val IPV4_INTERFACE_ADDRESS = "10.0.0.1"