fix: auto tunneling failure with rapid network changes

Fixes issue where rapid network switching could cause unexpected VPN connections and disconnection. Fixed by changing from real time network VPN triggers to three second interval checks.

Attempts to optimize battery drain while VPN connected by switching VPN statistics gathering to 10 second intervals.

Closes #11, Closes #12, Closes #10

app/build.gradle.kts

@@ -17,7 +17,7 @@ android {
 
     val versionMajor = 2
     val versionMinor = 3
-    val versionPatch = 1
+    val versionPatch = 2
     val versionBuild = 0
 
     defaultConfig {

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

@@ -0,0 +1,6 @@
+package com.zaneschepke.wireguardautotunnel
+
+object Constants {
+    const val VPN_CONNECTIVITY_CHECK_INTERVAL = 3000L;
+    const val VPN_STATISTIC_CHECK_INTERVAL = 10000L;
+}

app/src/main/java/com/zaneschepke/wireguardautotunnel/service/foreground/WireGuardConnectivityWatcherService.kt

@@ -8,7 +8,10 @@ import android.content.Intent
 import android.os.Bundle
 import android.os.PowerManager
 import android.os.SystemClock
+import androidx.compose.runtime.collectAsState
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.wireguard.android.backend.Tunnel
+import com.zaneschepke.wireguardautotunnel.Constants
 import com.zaneschepke.wireguardautotunnel.R
 import com.zaneschepke.wireguardautotunnel.repository.Repository
 import com.zaneschepke.wireguardautotunnel.service.network.MobileDataService
@@ -22,6 +25,9 @@ import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.single
 import kotlinx.coroutines.launch
 import timber.log.Timber
 import javax.inject.Inject
@@ -46,15 +52,14 @@ class WireGuardConnectivityWatcherService : ForegroundService() {
     @Inject
     lateinit var vpnService : VpnService
 
+    private var isWifiConnected = false;
+    private var isMobileDataConnected = false;
+    private var currentNetworkSSID = "";
+
     private lateinit var watcherJob : Job;
     private lateinit var setting : Settings
     private lateinit var tunnelId: String
 
-    private var connecting = false
-    private var disconnecting = false
-    private var isWifiConnected = false
-    private var isMobileDataConnected = false
-
     private var wakeLock: PowerManager.WakeLock? = null
     private val tag = this.javaClass.name;
 
@@ -136,6 +141,9 @@ class WireGuardConnectivityWatcherService : ForegroundService() {
                     watchForMobileDataConnectivityChanges()
                 }
             }
+            CoroutineScope(watcherJob).launch {
+                manageVpn()
+            }
         }
     }
 
@@ -149,17 +157,9 @@ class WireGuardConnectivityWatcherService : ForegroundService() {
                 is NetworkStatus.CapabilitiesChanged -> {
                     isMobileDataConnected = true
                     Timber.d("Mobile data capabilities changed")
-                    if(!disconnecting && !connecting) {
-                        if(!isWifiConnected && setting.isTunnelOnMobileDataEnabled
-                            && vpnService.getState() == Tunnel.State.DOWN)
-                            startVPN()
-                    }
                 }
                 is NetworkStatus.Unavailable -> {
                     isMobileDataConnected = false
-                    if(!disconnecting && !connecting) {
-                        if(!isWifiConnected && vpnService.getState() == Tunnel.State.UP) stopVPN()
-                    }
                     Timber.d("Lost mobile data connection")
                 }
             }
@@ -176,61 +176,52 @@ class WireGuardConnectivityWatcherService : ForegroundService() {
                     is NetworkStatus.CapabilitiesChanged -> {
                         Timber.d("Wifi capabilities changed")
                         isWifiConnected = true
-                        if (!connecting && !disconnecting) {
-                            Timber.d("Not connect and not disconnecting")
-                            val ssid = wifiService.getNetworkName(it.networkCapabilities);
-                            Timber.d("SSID: $ssid")
-                            if (!setting.trustedNetworkSSIDs.contains(ssid) && vpnService.getState() == Tunnel.State.DOWN) {
-                                Timber.d("Starting VPN Tunnel for untrusted network: $ssid")
-                                startVPN()
-                            } else if (!disconnecting && vpnService.getState() == Tunnel.State.UP && setting.trustedNetworkSSIDs.contains(
-                                    ssid
-                                )
-                            ) {
-                                Timber.d("Stopping VPN Tunnel for trusted network with ssid: $ssid")
-                                stopVPN()
-                            }
-                        }
+                        currentNetworkSSID = wifiService.getNetworkName(it.networkCapabilities) ?: "";
                     }
                     is NetworkStatus.Unavailable -> {
                         isWifiConnected = false
                         Timber.d("Lost Wi-Fi connection")
-                        if(!connecting || !disconnecting) {
-                            if(setting.isTunnelOnMobileDataEnabled && vpnService.getState() == Tunnel.State.DOWN
-                                && isMobileDataConnected){
-                                Timber.d("Wifi not available so starting vpn for mobile data")
-                                startVPN()
-                            }
-                            if(!setting.isTunnelOnMobileDataEnabled && vpnService.getState() == Tunnel.State.UP) {
-                                Timber.d("Lost WiFi connection, disabling vpn")
-                                stopVPN()
-                            }
-                        }
-
                     }
                 }
             }
         }
-    private fun startVPN() {
-        if(!connecting) {
-            connecting = true
-            ServiceTracker.actionOnService(
-                Action.START,
-                this.applicationContext as Application,
-                WireGuardTunnelService::class.java,
-                mapOf(getString(R.string.tunnel_extras_key) to tunnelId))
-            connecting = false
+
+    private suspend fun manageVpn() {
+        while(watcherJob.isActive) {
+            if(setting.isTunnelOnMobileDataEnabled &&
+                !isWifiConnected &&
+                isMobileDataConnected
+                && vpnService.getState() == Tunnel.State.DOWN) {
+                startVPN()
+            } else if(!setting.isTunnelOnMobileDataEnabled &&
+                !isWifiConnected &&
+                vpnService.getState() == Tunnel.State.UP) {
+                stopVPN()
+            } else if(isWifiConnected &&
+                !setting.trustedNetworkSSIDs.contains(currentNetworkSSID) &&
+                (vpnService.getState() != Tunnel.State.UP)) {
+                startVPN()
+            } else if((isWifiConnected &&
+                        setting.trustedNetworkSSIDs.contains(currentNetworkSSID)) &&
+                (vpnService.getState() == Tunnel.State.UP)) {
+                stopVPN()
+            }
+            delay(Constants.VPN_CONNECTIVITY_CHECK_INTERVAL)
         }
     }
+
+    private fun startVPN() {
+        ServiceTracker.actionOnService(
+            Action.START,
+            this.applicationContext as Application,
+            WireGuardTunnelService::class.java,
+            mapOf(getString(R.string.tunnel_extras_key) to tunnelId))
+    }
     private fun stopVPN() {
-        if(!disconnecting) {
-            disconnecting = true
-            ServiceTracker.actionOnService(
-                Action.STOP,
-                this.applicationContext as Application,
-                WireGuardTunnelService::class.java
-            )
-            disconnecting = false
-        }
+        ServiceTracker.actionOnService(
+            Action.STOP,
+            this.applicationContext as Application,
+            WireGuardTunnelService::class.java
+        )
     }
 }

app/src/main/java/com/zaneschepke/wireguardautotunnel/service/tunnel/WireGuardTunnel.kt

@@ -5,6 +5,7 @@ import com.wireguard.android.backend.BackendException
 import com.wireguard.android.backend.Statistics
 import com.wireguard.android.backend.Tunnel
 import com.wireguard.crypto.Key
+import com.zaneschepke.wireguardautotunnel.Constants
 import com.zaneschepke.wireguardautotunnel.service.tunnel.model.TunnelConfig
 import com.zaneschepke.wireguardautotunnel.util.NumberUtils
 import kotlinx.coroutines.CoroutineScope
@@ -103,7 +104,7 @@ class WireGuardTunnel @Inject constructor(private val backend : Backend,
                                 _handshakeStatus.emit(HandshakeStatus.NOT_STARTED)
                             }
                             if(neverHadHandshakeCounter <= HandshakeStatus.NEVER_CONNECTED_TO_UNHEALTHY_TIME_LIMIT_SEC) {
-                                neverHadHandshakeCounter++
+                                neverHadHandshakeCounter += 10
                             }
                             return@forEach
                         }
@@ -114,7 +115,7 @@ class WireGuardTunnel @Inject constructor(private val backend : Backend,
                         }
                     }
                     _lastHandshake.emit(handshakeMap)
-                    delay(1000)
+                    delay(Constants.VPN_STATISTIC_CHECK_INTERVAL)
                 }
             }
         }