Support monitoring tethered interface

This would be useful to be used in together with Instant Tethering + Turn off hotspot automatically.

Refine #26, #53.

mobile/src/main/java/be/mygod/vpnhotspot/IpNeighbourMonitoringService.kt

@@ -8,6 +8,7 @@ abstract class IpNeighbourMonitoringService : Service(), IpNeighbourMonitor.Call
     private var neighbours = emptyList<IpNeighbour>()
 
     protected abstract val activeIfaces: List<String>
+    protected open val inactiveIfaces get() = emptyList<String>()
 
     override fun onIpNeighbourAvailable(neighbours: List<IpNeighbour>) {
         this.neighbours = neighbours
@@ -20,6 +21,8 @@ abstract class IpNeighbourMonitoringService : Service(), IpNeighbourMonitor.Call
                     .distinctBy { it.lladdr }
                     .size
         }
-        ServiceNotification.startForeground(this, activeIfaces.associate { Pair(it, sizeLookup[it] ?: 0) })
+        ServiceNotification.startForeground(this,
+                activeIfaces.associate { Pair(it, sizeLookup[it] ?: 0) },
+                inactiveIfaces)
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/LocalOnlyHotspotService.kt

@@ -52,7 +52,7 @@ class LocalOnlyHotspotService : IpNeighbourMonitoringService() {
         } else {
             val routingManager = routingManager
             if (routingManager == null) {
-                this.routingManager = RoutingManager.LocalOnly(this, iface).apply { initRouting() }
+                this.routingManager = RoutingManager.LocalOnly(this, iface).apply { start() }
                 IpNeighbourMonitor.registerCallback(this)
             } else check(iface == routingManager.downstream)
         }
@@ -128,7 +128,7 @@ class LocalOnlyHotspotService : IpNeighbourMonitoringService() {
     }
 
     private fun unregisterReceiver() {
-        routingManager?.stop()
+        routingManager?.destroy()
         routingManager = null
         if (receiverRegistered) {
             unregisterReceiver(receiver)

mobile/src/main/java/be/mygod/vpnhotspot/RepeaterService.kt

@@ -277,7 +277,7 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
     private fun doStart(group: WifiP2pGroup) {
         binder.group = group
         check(routingManager == null)
-        routingManager = RoutingManager.LocalOnly(this, group.`interface`!!).apply { initRouting() }
+        routingManager = RoutingManager.LocalOnly(this, group.`interface`!!).apply { start() }
         status = Status.ACTIVE
         showNotification(group)
     }
@@ -309,7 +309,7 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
     }
     private fun clean() {
         unregisterReceiver()
-        routingManager?.stop()
+        routingManager?.destroy()
         routingManager = null
         status = Status.IDLE
         ServiceNotification.stopForeground(this)

mobile/src/main/java/be/mygod/vpnhotspot/RoutingManager.kt

@@ -30,15 +30,21 @@ abstract class RoutingManager(private val caller: Any, val downstream: String, p
         }
     }
 
-    var routing: Routing? = null
+    var started = false
-
+    private var routing: Routing? = null
     init {
-        app.onPreCleanRoutings[this] = { routing?.stop() }
-        app.onRoutingsCleaned[this] = { initRouting() }
         if (isWifi) WifiDoubleLock.acquire(this)
     }
 
-    fun initRouting() = try {
+    fun start(): Boolean {
+        check(!started)
+        started = true
+        app.onPreCleanRoutings[this] = { routing?.stop() }
+        app.onRoutingsCleaned[this] = { initRouting() }
+        return initRouting()
+    }
+
+    private fun initRouting() = try {
         routing = Routing(caller, downstream).apply {
             try {
                 configure()
@@ -58,9 +64,15 @@ abstract class RoutingManager(private val caller: Any, val downstream: String, p
     protected abstract fun Routing.configure()
 
     fun stop() {
+        if (!started) return
         routing?.revert()
-        if (isWifi) WifiDoubleLock.release(this)
         app.onPreCleanRoutings -= this
         app.onRoutingsCleaned -= this
+        started = false
+    }
+
+    fun destroy() {
+        if (isWifi) WifiDoubleLock.release(this)
+        stop()
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/ServiceNotification.kt

@@ -9,12 +9,14 @@ import androidx.core.app.NotificationCompat
 import androidx.core.content.ContextCompat
 import androidx.core.content.getSystemService
 import be.mygod.vpnhotspot.App.Companion.app
+import java.util.*
 
 object ServiceNotification {
     private const val CHANNEL = "tethering"
     private const val CHANNEL_ID = 1
 
-    private val deviceCountsMap = HashMap<Service, Map<String, Int>>()
+    private val deviceCountsMap = WeakHashMap<Service, Map<String, Int>>()
+    private val inactiveMap = WeakHashMap<Service, List<String>>()
     private val manager = app.getSystemService<NotificationManager>()!!
 
     private fun buildNotification(context: Context): Notification {
@@ -27,32 +29,29 @@ object ServiceNotification {
                         Intent(context, MainActivity::class.java), PendingIntent.FLAG_UPDATE_CURRENT))
                 .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
         val deviceCounts = deviceCountsMap.values.flatMap { it.entries }.sortedBy { it.key }
-        return when (deviceCounts.size) {
+        val inactive = inactiveMap.values.flatten()
-            0 -> builder.build()
+        var lines = deviceCounts.map { (dev, size) ->
-            1 -> {
+            context.resources.getQuantityString(R.plurals.notification_connected_devices, size, size, dev)
-                val (dev, size) = deviceCounts.single()
-                builder.setContentText(context.resources.getQuantityString(R.plurals.notification_connected_devices,
-                        size, size, dev))
-                        .build()
         }
-            else -> {
+        if (inactive.isNotEmpty()) {
+            lines += context.getString(R.string.notification_interfaces_inactive) + inactive.joinToString()
+        }
+        return if (lines.size <= 1) builder.setContentText(lines.singleOrNull()).build() else {
             val deviceCount = deviceCounts.sumBy { it.value }
+            val interfaceCount = deviceCounts.size + inactive.size
             NotificationCompat.BigTextStyle(builder
                     .setContentText(context.resources.getQuantityString(R.plurals.notification_connected_devices,
                             deviceCount, deviceCount,
                             context.resources.getQuantityString(R.plurals.notification_interfaces,
-                                        deviceCounts.size, deviceCounts.size))))
+                                    interfaceCount, interfaceCount))))
-                        .bigText(deviceCounts.joinToString("\n") { (dev, size) ->
+                    .bigText(lines.joinToString("\n"))
-                            context.resources.getQuantityString(R.plurals.notification_connected_devices,
-                                    size, size, dev)
-                        })
                     .build()
         }
     }
-    }
 
-    fun startForeground(service: Service, deviceCounts: Map<String, Int>) {
+    fun startForeground(service: Service, deviceCounts: Map<String, Int>, inactive: List<String> = emptyList()) {
         deviceCountsMap[service] = deviceCounts
+        if (inactive.isEmpty()) inactiveMap.remove(service) else inactiveMap[service] = inactive
         service.startForeground(CHANNEL_ID, buildNotification(service))
     }
     fun stopForeground(service: Service) {

mobile/src/main/java/be/mygod/vpnhotspot/TetheringService.kt

@@ -16,16 +16,22 @@ import kotlinx.coroutines.launch
 class TetheringService : IpNeighbourMonitoringService() {
     companion object {
         const val EXTRA_ADD_INTERFACES = "interface.add"
+        const val EXTRA_ADD_INTERFACE_MONITOR = "interface.add.monitor"
         const val EXTRA_REMOVE_INTERFACE = "interface.remove"
     }
 
     inner class Binder : android.os.Binder() {
         val routingsChanged = Event0()
-
+        val monitoredIfaces get() = synchronized(downstreams) {
-        fun isActive(iface: String): Boolean = synchronized(downstreams) { downstreams.containsKey(iface) }
+            downstreams.values.filter { it.monitor }.map { it.downstream }
         }
 
-    private inner class Downstream(caller: Any, downstream: String) :
+        fun isActive(iface: String) = synchronized(downstreams) { downstreams.containsKey(iface) }
+        fun isInactive(iface: String) = synchronized(downstreams) { downstreams[iface] }?.run { !started && monitor }
+        fun monitored(iface: String) = synchronized(downstreams) { downstreams[iface] }?.monitor
+    }
+
+    private inner class Downstream(caller: Any, downstream: String, var monitor: Boolean = false) :
             RoutingManager(caller, downstream, TetherType.ofInterface(downstream).isWifi) {
         override fun Routing.configure() {
             forward()
@@ -41,12 +47,23 @@ class TetheringService : IpNeighbourMonitoringService() {
     private val receiver = broadcastReceiver { _, intent ->
         val extras = intent.extras ?: return@broadcastReceiver
         synchronized(downstreams) {
-            for (iface in downstreams.keys - TetheringManager.getTetheredIfaces(extras))
+            val toRemove = downstreams.toMutableMap()   // make a copy
-                downstreams.remove(iface)?.stop()
+            for (iface in TetheringManager.getTetheredIfaces(extras)) {
+                val downstream = toRemove.remove(iface) ?: continue
+                if (downstream.monitor && !downstream.started) downstream.start()
+            }
+            for ((iface, downstream) in toRemove) {
+                if (downstream.monitor) downstream.stop() else downstreams.remove(iface)?.destroy()
+            }
             onDownstreamsChangedLocked()
         }
     }
-    override val activeIfaces get() = synchronized(downstreams) { downstreams.keys.toList() }
+    override val activeIfaces get() = synchronized(downstreams) {
+        downstreams.values.filter { it.started }.map { it.downstream }
+    }
+    override val inactiveIfaces get() = synchronized(downstreams) {
+        downstreams.values.filter { !it.started }.map { it.downstream }
+    }
 
     private fun onDownstreamsChangedLocked() {
         if (downstreams.isEmpty()) {
@@ -67,22 +84,30 @@ class TetheringService : IpNeighbourMonitoringService() {
     override fun onBind(intent: Intent?) = binder
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
-        if (intent != null) {
+        if (intent != null) synchronized(downstreams) {
-            val ifaces = intent.getStringArrayExtra(EXTRA_ADD_INTERFACES) ?: emptyArray()
+            for (iface in intent.getStringArrayExtra(EXTRA_ADD_INTERFACES) ?: emptyArray()) {
-            synchronized(downstreams) {
+                if (downstreams[iface] == null) Downstream(this, iface).apply {
-                for (iface in ifaces) Downstream(this, iface).let { downstream ->
+                    if (start()) check(downstreams.put(iface, this) == null) else destroy()
-                    if (downstream.initRouting()) downstreams[iface] = downstream else downstream.stop()
                 }
-                downstreams.remove(intent.getStringExtra(EXTRA_REMOVE_INTERFACE))?.stop()
+            }
+            intent.getStringExtra(EXTRA_ADD_INTERFACE_MONITOR)?.let { iface ->
+                val downstream = downstreams[iface]
+                if (downstream == null) Downstream(this, iface, true).apply {
+                    start()
+                    check(downstreams.put(iface, this) == null)
+                    downstreams[iface] = this
+                } else downstream.monitor = true
+            }
+            downstreams.remove(intent.getStringExtra(EXTRA_REMOVE_INTERFACE))?.destroy()
+            updateNotification()    // call this first just in case we are shutting down immediately
             onDownstreamsChangedLocked()
-            }
         } else if (downstreams.isEmpty()) stopSelf(startId)
         return START_NOT_STICKY
     }
 
     override fun onDestroy() {
         synchronized(downstreams) {
-            downstreams.values.forEach { it.stop() }    // force clean to prevent leakage
+            downstreams.values.forEach { it.destroy() } // force clean to prevent leakage
             unregisterReceiver()
         }
         super.onDestroy()

mobile/src/main/java/be/mygod/vpnhotspot/manage/InterfaceManager.kt

@@ -4,6 +4,7 @@ import android.content.Intent
 import android.view.View
 import androidx.core.content.ContextCompat
 import androidx.recyclerview.widget.RecyclerView
+import be.mygod.vpnhotspot.R
 import be.mygod.vpnhotspot.TetheringService
 import be.mygod.vpnhotspot.databinding.ListitemInterfaceBinding
 import be.mygod.vpnhotspot.net.TetherType
@@ -30,12 +31,14 @@ class InterfaceManager(private val parent: TetheringFragment, val iface: String)
     }
     private inner class Data : be.mygod.vpnhotspot.manage.Data() {
         override val icon get() = TetherType.ofInterface(iface).icon
-        override val title get() = iface
+        override val title get() = if (parent.binder?.monitored(iface) == true) {
+            parent.getString(R.string.tethering_state_monitored, iface)
+        } else iface
         override val text get() = addresses
         override val active get() = parent.binder?.isActive(iface) == true
     }
 
-    private val addresses = parent.ifaceLookup[iface]?.formatAddresses() ?: ""
+    private val addresses = parent.ifaceLookup[iface] ?.formatAddresses(parent.binder?.isInactive(iface) == true) ?: ""
     override val type get() = VIEW_TYPE_INTERFACE
     private val data = Data()
 

mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt

@@ -9,29 +9,26 @@ import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
 import android.os.IBinder
-import android.view.LayoutInflater
+import android.view.*
-import android.view.View
+import androidx.core.content.ContextCompat
-import android.view.ViewGroup
 import androidx.databinding.DataBindingUtil
 import androidx.fragment.app.Fragment
 import androidx.recyclerview.widget.DefaultItemAnimator
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
-import be.mygod.vpnhotspot.LocalOnlyHotspotService
+import be.mygod.vpnhotspot.*
-import be.mygod.vpnhotspot.R
-import be.mygod.vpnhotspot.RepeaterService
-import be.mygod.vpnhotspot.TetheringService
 import be.mygod.vpnhotspot.databinding.FragmentTetheringBinding
 import be.mygod.vpnhotspot.net.TetherType
 import be.mygod.vpnhotspot.net.TetheringManager
 import be.mygod.vpnhotspot.util.ServiceForegroundConnector
 import be.mygod.vpnhotspot.util.broadcastReceiver
+import kotlinx.android.synthetic.main.activity_main.*
 import timber.log.Timber
 import java.net.NetworkInterface
 import java.net.SocketException
 
-class TetheringFragment : Fragment(), ServiceConnection {
+class TetheringFragment : Fragment(), ServiceConnection, MenuItem.OnMenuItemClickListener {
     companion object {
         const val START_LOCAL_ONLY_HOTSPOT = 1
         const val REPEATER_EDIT_CONFIGURATION = 2
@@ -63,7 +60,10 @@ class TetheringFragment : Fragment(), ServiceConnection {
             val list = ArrayList<Manager>()
             if (RepeaterService.supported) list.add(repeaterManager)
             if (Build.VERSION.SDK_INT >= 26) list.add(localOnlyHotspotManager)
-            list.addAll(activeIfaces.map { InterfaceManager(this@TetheringFragment, it) }.sortedBy { it.iface })
+            val monitoredIfaces = binder?.monitoredIfaces ?: emptyList()
+            updateMonitorList(activeIfaces - monitoredIfaces)
+            list.addAll((activeIfaces + monitoredIfaces).toSortedSet()
+                    .map { InterfaceManager(this@TetheringFragment, it) })
             list.add(ManageBar)
             if (Build.VERSION.SDK_INT >= 24) {
                 list.addAll(tetherManagers)
@@ -94,6 +94,27 @@ class TetheringFragment : Fragment(), ServiceConnection {
                 extras.getStringArrayList(TetheringManager.EXTRA_ERRORED_TETHER)!!)
     }
 
+    private fun updateMonitorList(canMonitor: List<String> = emptyList()) {
+        val toolbar = requireActivity().toolbar
+        val menu = toolbar.menu
+        if (canMonitor.isEmpty()) menu.removeItem(R.id.monitor) else {
+            var item = menu.findItem(R.id.monitor)
+            if (item == null) {
+                toolbar.inflateMenu(R.menu.toolbar_monitor)
+                item = menu.findItem(R.id.monitor)!!
+            }
+            item.subMenu.apply {
+                clear()
+                canMonitor.sorted().forEach { add(it).setOnMenuItemClickListener(this@TetheringFragment) }
+            }
+        }
+    }
+    override fun onMenuItemClick(item: MenuItem?): Boolean {
+        ContextCompat.startForegroundService(requireContext(), Intent(context, TetheringService::class.java)
+                .putExtra(TetheringService.EXTRA_ADD_INTERFACE_MONITOR, item?.title ?: return false))
+        return true
+    }
+
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         binding = DataBindingUtil.inflate(inflater, R.layout.fragment_tethering, container, false)
         binding.setLifecycleOwner(this)
@@ -127,7 +148,13 @@ class TetheringFragment : Fragment(), ServiceConnection {
 
     override fun onServiceConnected(name: ComponentName?, service: IBinder?) {
         binder = service as TetheringService.Binder
-        service.routingsChanged[this] = { adapter.notifyDataSetChanged() }
+        service.routingsChanged[this] = {
+            requireContext().apply {
+                // flush tethered interfaces
+                unregisterReceiver(receiver)
+                registerReceiver(receiver, IntentFilter(TetheringManager.ACTION_TETHER_STATE_CHANGED))
+            }
+        }
         requireContext().registerReceiver(receiver, IntentFilter(TetheringManager.ACTION_TETHER_STATE_CHANGED))
     }
 
@@ -136,4 +163,9 @@ class TetheringFragment : Fragment(), ServiceConnection {
         binder = null
         requireContext().unregisterReceiver(receiver)
     }
+
+    override fun onDestroy() {
+        updateMonitorList()
+        super.onDestroy()
+    }
 }

mobile/src/main/java/be/mygod/vpnhotspot/net/Routing.kt

@@ -41,6 +41,11 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
          */
         val IPTABLES = if (Build.VERSION.SDK_INT >= 26) "iptables -w 1" else "iptables -w"
 
+        /**
+         * For debugging: check that we do not start a Routing for the same interface twice.
+         */
+        private var downstreams = mutableSetOf<String>()
+
         fun clean() {
             TrafficRecorder.clean()
             RootSession.use {
@@ -54,6 +59,7 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
                 it.execQuiet("while ip rule del priority $RULE_PRIORITY_UPSTREAM; do done")
                 it.execQuiet("while ip rule del priority $RULE_PRIORITY_UPSTREAM_FALLBACK; do done")
             }
+            downstreams.clear()
         }
 
         private fun RootSession.Transaction.iptables(command: String, revert: String) {
@@ -82,6 +88,10 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
         override val message: String get() = app.getString(R.string.exception_interface_not_found)
     }
 
+    init {
+        check(downstreams.add(downstream)) { "Double routing detected" }
+    }
+
     private val hostAddress = try {
         NetworkInterface.getByName(downstream)!!.interfaceAddresses!!.asSequence().single { it.address is Inet4Address }
     } catch (e: Exception) {
@@ -302,5 +312,6 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
         fallbackUpstream.subrouting?.transaction?.revert()
         upstream.subrouting?.transaction?.revert()
         transaction.revert()
+        check(downstreams.remove(downstream)) { "Double reverting detected" }
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt

@@ -58,11 +58,11 @@ fun makeMacSpan(mac: String) = if (app.hasTouch) SpannableString(mac).apply {
     setSpan(CustomTabsUrlSpan("https://macvendors.co/results/$mac"), 0, length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
 } else mac
 
-fun NetworkInterface.formatAddresses() = SpannableStringBuilder().apply {
+fun NetworkInterface.formatAddresses(macOnly: Boolean = false) = SpannableStringBuilder().apply {
     try {
         hardwareAddress?.apply { appendln(makeMacSpan(asIterable().macToString())) }
     } catch (_: SocketException) { }
-    for (address in interfaceAddresses) {
+    if (!macOnly) for (address in interfaceAddresses) {
         append(makeIpSpan(address.address))
         appendln("/${address.networkPrefixLength}")
     }

mobile/src/main/res/drawable/ic_image_remove_red_eye.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0"
+        android:tint="?attr/colorControlNormal">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M12,4.5C7,4.5 2.73,7.61 1,12c1.73,4.39 6,7.5 11,7.5s9.27,-3.11 11,-7.5c-1.73,-4.39 -6,-7.5 -11,-7.5zM12,17c-2.76,0 -5,-2.24 -5,-5s2.24,-5 5,-5 5,2.24 5,5 -2.24,5 -5,5zM12,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3 3,-1.34 3,-3 -1.34,-3 -3,-3z"/>
+</vector>

mobile/src/main/res/menu/toolbar_monitor.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+      xmlns:app="http://schemas.android.com/apk/res-auto">
+    <item android:id="@+id/monitor"
+          android:icon="@drawable/ic_image_remove_red_eye"
+          android:title="@string/tethering_monitor"
+          app:showAsAction="always">
+        <menu/>
+    </item>
+</menu>

mobile/src/main/res/values-zh-rCN/strings.xml

@@ -39,6 +39,9 @@
     <string name="tethering_temp_hotspot_failure_incompatible_mode">模式不兼容</string>
     <string name="tethering_temp_hotspot_failure_tethering_disallowed">共享被禁用</string>
 
+    <string name="tethering_monitor">监视…</string>
+    <string name="tethering_state_monitored">%s（监视）</string>
+
     <string name="tethering_manage">管理系统共享…</string>
     <string name="tethering_manage_offload_enabled">若 VPN 共享无法使用，请尝试禁用“开发者选项”中的“网络共享硬件加速”。</string>
     <!--
@@ -122,6 +125,7 @@
     <plurals name="notification_interfaces">
         <item quantity="other">%d 个接口</item>
     </plurals>
+    <string name="notification_interfaces_inactive">不活跃：</string>
 
     <string name="failure_reason_unknown">未知 #%d</string>
     <string name="exception_interface_not_found">错误：未找到下游接口</string>

mobile/src/main/res/values/strings.xml

@@ -49,6 +49,9 @@
     <string name="tethering_temp_hotspot_failure_incompatible_mode">incompatible mode</string>
     <string name="tethering_temp_hotspot_failure_tethering_disallowed">tethering disallowed</string>
 
+    <string name="tethering_monitor">Monitor…</string>
+    <string name="tethering_state_monitored">%s (monitored)</string>
+
     <string name="tethering_manage">Manage system tethering…</string>
     <string name="tethering_manage_offload_enabled">Please disable Tethering hardware acceleration in Developer options
         if VPN tethering does not work.</string>
@@ -131,6 +134,7 @@
         <item quantity="one">%d interface</item>
         <item quantity="other">%d interfaces</item>
     </plurals>
+    <string name="notification_interfaces_inactive">"Inactive: "</string>
 
     <string name="failure_reason_unknown">unknown #%d</string>
     <string name="exception_interface_not_found">Fatal: Downstream interface not found</string>