Merge pull request #187 from Mygod/stacked-links

Support stacked links

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

@@ -2,6 +2,7 @@ package be.mygod.vpnhotspot.net
 
 import android.annotation.TargetApi
 import android.net.LinkProperties
+import android.net.RouteInfo
 import android.os.Build
 import androidx.annotation.RequiresApi
 import be.mygod.vpnhotspot.App.Companion.app
@@ -13,9 +14,7 @@ import be.mygod.vpnhotspot.net.monitor.UpstreamMonitor
 import be.mygod.vpnhotspot.room.AppDatabase
 import be.mygod.vpnhotspot.root.RootManager
 import be.mygod.vpnhotspot.root.RoutingCommands
-import be.mygod.vpnhotspot.util.RootSession
-import be.mygod.vpnhotspot.util.if_nametoindex
-import be.mygod.vpnhotspot.util.parseNumericAddress
+import be.mygod.vpnhotspot.util.*
 import be.mygod.vpnhotspot.widget.SmartSnackbar
 import kotlinx.coroutines.CancellationException
 import timber.log.Timber
@@ -180,52 +179,64 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
             }
         }
 
-        var subrouting: Subrouting? = null
-        var dns: List<InetAddress> = emptyList()
+        var subrouting = mutableMapOf<String, Subrouting>()
+        var dns = emptyList<Pair<InetAddress, String?>>()
 
-        override fun onAvailable(ifname: String, properties: LinkProperties) = synchronized(this@Routing) {
+        override fun onAvailable(properties: LinkProperties?) = synchronized(this@Routing) {
             if (stopped) return
-            val subrouting = subrouting
-            when {
-                subrouting != null -> check(subrouting.upstream == ifname) { "${subrouting.upstream} != $ifname" }
-                !upstreams.add(ifname) -> return
-                else -> this.subrouting = try {
-                    Subrouting(priority, ifname)
+            val toRemove = subrouting.keys.toMutableSet()
+            for (ifname in properties?.allInterfaceNames ?: emptyList()) {
+                if (toRemove.remove(ifname) || !upstreams.add(ifname)) continue
+                try {
+                    subrouting[ifname] = Subrouting(priority, ifname)
                 } catch (e: Exception) {
                     SmartSnackbar.make(e).show()
                     if (e !is CancellationException) Timber.w(e)
-                    null
                 }
             }
-            dns = properties.dnsServers
-            updateDnsRoute()
+            for (ifname in toRemove) {
+                subrouting.remove(ifname)?.transaction?.revert()
+                check(upstreams.remove(ifname))
             }
-
-        override fun onLost() = synchronized(this@Routing) {
-            if (stopped) return
-            val subrouting = subrouting ?: return
-            // we could be removing fallback subrouting which no collision could ever happen, check before removing
-            subrouting.upstream?.let { check(upstreams.remove(it)) }
-            subrouting.transaction.revert()
-            this.subrouting = null
-            dns = emptyList()
+            val routes = properties?.allRoutes
+            dns = properties?.dnsServers?.map { dest ->
+                // based on:
+                // https://cs.android.com/android/platform/superproject/+/master:frameworks/base/packages/Tethering/src/com/android/networkstack/tethering/TetheringInterfaceUtils.java;l=88;drc=master
+                // https://cs.android.com/android/platform/superproject/+/master:frameworks/libs/net/common/framework/android/net/util/NetUtils.java;l=44;drc=de5905fe0407a1f5e115423d56c948ee2400683d
+                val size = dest.address.size
+                var bestRoute: RouteInfo? = null
+                for (route in routes!!) {
+                    if (route.destination.rawAddress.size == size &&
+                            (bestRoute == null ||
+                                    bestRoute.destination.prefixLength < route.destination.prefixLength) &&
+                            route.matches(dest)) {
+                        bestRoute = route
+                    }
+                }
+                dest to bestRoute?.`interface`
+            } ?: emptyList()
             updateDnsRoute()
         }
     }
     private val fallbackUpstream = object : Upstream(RULE_PRIORITY_UPSTREAM_FALLBACK) {
         var fallbackInactive = true
+
+        override fun onAvailable(properties: LinkProperties?) {
+            check(fallbackInactive)
+            super.onAvailable(properties)
+        }
+
         override fun onFallback() = synchronized(this@Routing) {
             if (stopped) return
             fallbackInactive = false
-            check(subrouting == null)
-            subrouting = try {
-                Subrouting(priority)
+            check(subrouting.isEmpty() && upstreams.add(""))
+            try {
+                subrouting[""] = Subrouting(priority)
             } catch (e: Exception) {
                 SmartSnackbar.make(e).show()
                 if (e !is CancellationException) Timber.w(e)
-                null
             }
-            dns = listOf(parseNumericAddress("8.8.8.8"))
+            dns = listOf(parseNumericAddress("8.8.8.8") to null)
             updateDnsRoute()
         }
     }
@@ -334,8 +345,9 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
     private var currentDns: DnsRoute? = null
     private fun updateDnsRoute() {
         val selected = sequenceOf(upstream, fallbackUpstream).flatMap { upstream ->
-            val ifindex = upstream.subrouting?.ifindex ?: 0
-            if (ifindex == 0) emptySequence() else upstream.dns.asSequence().map { ifindex to it }
+            upstream.dns.asSequence().map { (server, iface) ->
+                ((if (iface != null) upstream.subrouting[iface]?.ifindex else null) ?: 0) to server
+            }
         }.firstOrNull { it.second is Inet4Address }
         val ifindex = selected?.first ?: 0
         var dns = selected?.second?.hostAddress
@@ -378,8 +390,8 @@ class Routing(private val caller: Any, private val downstream: String) : IpNeigh
         synchronized(this) { clients.values.forEach { it.close() } }
         currentDns?.transaction?.revert()
         disableSystem?.revert()
-        fallbackUpstream.subrouting?.transaction?.revert()
-        upstream.subrouting?.transaction?.revert()
+        fallbackUpstream.subrouting.values.forEach { it.transaction.revert() }
+        upstream.subrouting.values.forEach { it.transaction.revert() }
         transaction.revert()
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/DefaultNetworkMonitor.kt

@@ -9,11 +9,9 @@ import android.os.Build
 import be.mygod.vpnhotspot.util.Services
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
-import timber.log.Timber
 
 object DefaultNetworkMonitor : UpstreamMonitor() {
     private var registered = false
-    private var currentNetwork: Network? = null
     override var currentLinkProperties: LinkProperties? = null
         private set
     /**
@@ -27,62 +25,30 @@ object DefaultNetworkMonitor : UpstreamMonitor() {
     private val networkCallback = object : ConnectivityManager.NetworkCallback() {
         override fun onAvailable(network: Network) {
             val properties = Services.connectivity.getLinkProperties(network)
-            val ifname = properties?.interfaceName ?: return
-            var switching = false
             synchronized(this@DefaultNetworkMonitor) {
-                val oldProperties = currentLinkProperties
-                if (currentNetwork != network || ifname != oldProperties?.interfaceName) {
-                    switching = true    // we are using the other default network now
-                    currentNetwork = network
-                }
                 currentLinkProperties = properties
                 callbacks.toList()
-            }.forEach {
-                if (switching) it.onLost()
-                it.onAvailable(ifname, properties)
-            }
+            }.forEach { it.onAvailable(properties) }
         }
 
         override fun onLinkPropertiesChanged(network: Network, properties: LinkProperties) {
-            var losing = true
-            var ifname: String?
             synchronized(this@DefaultNetworkMonitor) {
-                if (currentNetwork == null) {
-                    onAvailable(network)
-                    return
-                }
-                if (currentNetwork != network) return
-                val oldProperties = currentLinkProperties!!
                 currentLinkProperties = properties
-                ifname = properties.interfaceName
-                when (ifname) {
-                    null -> Timber.w("interfaceName became null: $oldProperties -> $properties")
-                    oldProperties.interfaceName -> losing = false
-                    else -> Timber.w(RuntimeException("interfaceName changed: $oldProperties -> $properties"))
-                }
                 callbacks.toList()
-            }.forEach {
-                if (losing) {
-                    if (ifname == null) return onLost(network)
-                    it.onLost()
-                }
-                ifname?.let { ifname -> it.onAvailable(ifname, properties) }
-            }
+            }.forEach { it.onAvailable(properties) }
         }
 
         override fun onLost(network: Network) = synchronized(this@DefaultNetworkMonitor) {
-            if (currentNetwork != network) return
-            currentNetwork = null
             currentLinkProperties = null
             callbacks.toList()
-        }.forEach { it.onLost() }
+        }.forEach { it.onAvailable() }
     }
 
     override fun registerCallbackLocked(callback: Callback) {
         if (registered) {
             val currentLinkProperties = currentLinkProperties
             if (currentLinkProperties != null) GlobalScope.launch {
-                callback.onAvailable(currentLinkProperties.interfaceName!!, currentLinkProperties)
+                callback.onAvailable(currentLinkProperties)
             }
         } else {
             if (Build.VERSION.SDK_INT in 24..27) @TargetApi(24) {
@@ -103,7 +69,6 @@ object DefaultNetworkMonitor : UpstreamMonitor() {
         if (!registered) return
         Services.connectivity.unregisterNetworkCallback(networkCallback)
         registered = false
-        currentNetwork = null
         currentLinkProperties = null
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/FallbackUpstreamMonitor.kt

@@ -34,10 +34,7 @@ abstract class FallbackUpstreamMonitor private constructor() : UpstreamMonitor()
                     }
                     val new = generateMonitor()
                     monitor = new
-                    for (callback in callbacks) {
-                        callback.onLost()
-                        new.registerCallback(callback)
-                    }
+                    for (callback in callbacks) new.registerCallback(callback)
                 }
             }
         }

mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/InterfaceMonitor.kt

@@ -1,49 +1,85 @@
 package be.mygod.vpnhotspot.net.monitor
 
+import android.net.ConnectivityManager
 import android.net.LinkProperties
+import android.net.Network
+import android.net.NetworkCapabilities
 import be.mygod.vpnhotspot.util.Services
 import be.mygod.vpnhotspot.util.allInterfaceNames
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
+import timber.log.Timber
 
-class InterfaceMonitor(val iface: String) : UpstreamMonitor() {
-    private fun setPresent(present: Boolean) {
-        var available: Pair<String, LinkProperties>? = null
-        synchronized(this) {
-            val old = currentIface != null
-            if (present == old) return
-            currentIface = if (present) iface else null
-            if (present) available = iface to (currentLinkProperties ?: return)
-            callbacks.toList()
-        }.forEach {
-            @Suppress("NAME_SHADOWING")
-            val available = available
-            if (available != null) {
-                val (iface, lp) = available
-                it.onAvailable(iface, lp)
-            } else it.onLost()
-        }
-    }
-
+class InterfaceMonitor(ifaceRegex: String) : UpstreamMonitor() {
+    private val iface = ifaceRegex.toRegex()
+    private val request = networkRequestBuilder().apply {
+        removeCapability(NetworkCapabilities.NET_CAPABILITY_NOT_RESTRICTED)
+        removeCapability(NetworkCapabilities.NET_CAPABILITY_TRUSTED)
+        removeCapability(NetworkCapabilities.NET_CAPABILITY_NOT_VPN)
+    }.build()
     private var registered = false
-    override var currentIface: String? = null
-        private set
-    override val currentLinkProperties get() = Services.connectivity.allNetworks
-            .map { Services.connectivity.getLinkProperties(it) }
-            .singleOrNull { it?.allInterfaceNames?.contains(iface) == true }
+
+    private val available = HashMap<Network, LinkProperties?>()
+    private var currentNetwork: Network? = null
+    override val currentLinkProperties: LinkProperties? get() = currentNetwork?.let { available[it] }
+    private val networkCallback = object : ConnectivityManager.NetworkCallback() {
+        override fun onAvailable(network: Network) {
+            val properties = Services.connectivity.getLinkProperties(network)
+            if (properties?.allInterfaceNames?.any(iface::matches) != true) return
+            synchronized(this@InterfaceMonitor) {
+                available[network] = properties
+                currentNetwork = network
+                callbacks.toList()
+            }.forEach { it.onAvailable(properties) }
+        }
+
+        override fun onLinkPropertiesChanged(network: Network, properties: LinkProperties) {
+            val matched = properties.allInterfaceNames.any(iface::matches)
+            synchronized(this@InterfaceMonitor) {
+                if (!matched) {
+                    if (currentNetwork == network) currentNetwork = null
+                    available.remove(network)
+                    return
+                }
+                available[network] = properties
+                if (currentNetwork == null) currentNetwork = network
+                else if (currentNetwork != network) return
+                callbacks.toList()
+            }.forEach { it.onAvailable(properties) }
+        }
+
+        override fun onLost(network: Network) {
+            var properties: LinkProperties? = null
+            synchronized(this@InterfaceMonitor) {
+                if (available.remove(network) == null || currentNetwork != network) return
+                if (available.isNotEmpty()) {
+                    val next = available.entries.first()
+                    currentNetwork = next.key
+                    Timber.d("Switching to ${next.value} for $iface")
+                    properties = next.value
+                } else currentNetwork = null
+                callbacks.toList()
+            }.forEach { it.onAvailable(properties) }
+        }
+    }
 
     override fun registerCallbackLocked(callback: Callback) {
-        if (!registered) {
-            IpLinkMonitor.registerCallback(this, iface, this::setPresent)
+        if (registered) {
+            val currentLinkProperties = currentLinkProperties
+            if (currentLinkProperties != null) GlobalScope.launch {
+                callback.onAvailable(currentLinkProperties)
+            }
+        } else {
+            Services.connectivity.registerNetworkCallback(request, networkCallback)
             registered = true
-        } else if (currentIface != null) GlobalScope.launch {
-            callback.onAvailable(iface, currentLinkProperties ?: return@launch)
         }
     }
 
     override fun destroyLocked() {
-        IpLinkMonitor.unregisterCallback(this)
-        currentIface = null
+        if (!registered) return
+        Services.connectivity.unregisterNetworkCallback(networkCallback)
         registered = false
+        available.clear()
+        currentNetwork = null
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/IpLinkMonitor.kt

@@ -1,44 +0,0 @@
-package be.mygod.vpnhotspot.net.monitor
-
-class IpLinkMonitor private constructor() : IpMonitor() {
-    companion object {
-        /**
-         * Based on: https://android.googlesource.com/platform/external/iproute2/+/70556c1/ip/ipaddress.c#1053
-         */
-        private val parser = "^(Deleted )?-?\\d+: ([^:@]+)".toRegex()
-
-        private val callbacks = HashMap<Any, Pair<String, (Boolean) -> Unit>>()
-        private var instance: IpLinkMonitor? = null
-
-        fun registerCallback(owner: Any, iface: String, callback: (Boolean) -> Unit) = synchronized(this) {
-            check(callbacks.put(owner, Pair(iface, callback)) == null)
-            var monitor = instance
-            if (monitor == null) {
-                monitor = IpLinkMonitor()
-                instance = monitor
-            } else monitor.flushAsync()
-        }
-        fun unregisterCallback(owner: Any) = synchronized(this) {
-            if (callbacks.remove(owner) == null || callbacks.isNotEmpty()) return@synchronized
-            instance?.destroy()
-            instance = null
-        }
-    }
-
-    override val monitoredObject: String get() = "link"
-
-    override fun processLine(line: String) {
-        val match = parser.find(line) ?: return
-        val iface = match.groupValues[2]
-        val present = match.groupValues[1].isEmpty()
-        synchronized(IpLinkMonitor) {
-            for ((target, callback) in callbacks.values) if (target == iface) callback(present)
-        }
-    }
-
-    override fun processLines(lines: Sequence<String>) {
-        val present = HashSet<String>()
-        for (it in lines) present.add((parser.find(it) ?: continue).groupValues[2])
-        synchronized(IpLinkMonitor) { for ((iface, callback) in callbacks.values) callback(present.contains(iface)) }
-    }
-}

mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/UpstreamMonitor.kt

@@ -37,18 +37,15 @@ abstract class UpstreamMonitor {
             if (key == KEY) GlobalScope.launch {    // prevent callback called in main
                 synchronized(this) {
                     val old = monitor
-                    val (active, callbacks) = synchronized(old) {
-                        (old.currentIface != null) to old.callbacks.toList().also {
+                    val callbacks = synchronized(old) {
+                        old.callbacks.toList().also {
                             old.callbacks.clear()
                             old.destroyLocked()
                         }
                     }
                     val new = generateMonitor()
                     monitor = new
-                    for (callback in callbacks) {
-                        if (active) callback.onLost()
-                        new.registerCallback(callback)
-                    }
+                    for (callback in callbacks) new.registerCallback(callback)
                 }
             }
         }
@@ -56,14 +53,9 @@ abstract class UpstreamMonitor {
 
     interface Callback {
         /**
-         * Called if some interface is available. This might be called on different ifname without having called onLost.
-         * This might also be called on the same ifname but with updated link properties.
+         * Called if some possibly stacked interface is available
          */
-        fun onAvailable(ifname: String, properties: LinkProperties)
-        /**
-         * Called if no interface is available.
-         */
-        fun onLost()
+        fun onAvailable(properties: LinkProperties? = null)
         /**
          * Called on API 23- from DefaultNetworkMonitor. This indicates that there isn't a good way of telling the
          * default network (see DefaultNetworkMonitor) and we are using rules at priority 22000
@@ -77,7 +69,6 @@ abstract class UpstreamMonitor {
 
     val callbacks = mutableSetOf<Callback>()
     protected abstract val currentLinkProperties: LinkProperties?
-    open val currentIface: String? get() = currentLinkProperties?.interfaceName
     protected abstract fun registerCallbackLocked(callback: Callback)
     abstract fun destroyLocked()
 

mobile/src/main/java/be/mygod/vpnhotspot/net/monitor/VpnMonitor.kt

@@ -16,71 +16,40 @@ object VpnMonitor : UpstreamMonitor() {
             .build()
     private var registered = false
 
-    private val available = HashMap<Network, LinkProperties>()
+    private val available = HashMap<Network, LinkProperties?>()
     private var currentNetwork: Network? = null
-    override val currentLinkProperties: LinkProperties? get() {
-        val currentNetwork = currentNetwork
-        return if (currentNetwork == null) null else available[currentNetwork]
-    }
+    override val currentLinkProperties: LinkProperties? get() = currentNetwork?.let { available[it] }
     private val networkCallback = object : ConnectivityManager.NetworkCallback() {
         override fun onAvailable(network: Network) {
             val properties = Services.connectivity.getLinkProperties(network)
-            val ifname = properties?.interfaceName ?: return
-            var switching = false
             synchronized(this@VpnMonitor) {
-                val oldProperties = available.put(network, properties)
-                if (currentNetwork != network || ifname != oldProperties?.interfaceName) {
-                    if (currentNetwork != null) switching = true
+                available[network] = properties
                 currentNetwork = network
-                }
                 callbacks.toList()
-            }.forEach {
-                if (switching) it.onLost()
-                it.onAvailable(ifname, properties)
-            }
+            }.forEach { it.onAvailable(properties) }
         }
 
         override fun onLinkPropertiesChanged(network: Network, properties: LinkProperties) {
-            var losing = true
-            var ifname: String?
             synchronized(this@VpnMonitor) {
-                if (currentNetwork == null) {
-                    onAvailable(network)
-                    return
-                }
-                if (currentNetwork != network) return
-                val oldProperties = available.put(network, properties)!!
-                ifname = properties.interfaceName
-                when (ifname) {
-                    null -> Timber.w("interfaceName became null: $oldProperties -> $properties")
-                    oldProperties.interfaceName -> losing = false
-                    else -> Timber.w("interfaceName changed: $oldProperties -> $properties")
-                }
+                available[network] = properties
+                if (currentNetwork == null) currentNetwork = network
+                else if (currentNetwork != network) return
                 callbacks.toList()
-            }.forEach {
-                if (losing) {
-                    if (ifname == null) return onLost(network)
-                    it.onLost()
-                }
-                ifname?.let { ifname -> it.onAvailable(ifname, properties) }
-            }
+            }.forEach { it.onAvailable(properties) }
         }
 
         override fun onLost(network: Network) {
-            var newProperties: LinkProperties? = null
+            var properties: LinkProperties? = null
             synchronized(this@VpnMonitor) {
                 if (available.remove(network) == null || currentNetwork != network) return
                 if (available.isNotEmpty()) {
                     val next = available.entries.first()
                     currentNetwork = next.key
-                    Timber.d("Switching to ${next.value.interfaceName} as VPN interface")
-                    newProperties = next.value
+                    Timber.d("Switching to ${next.value} as VPN interface")
+                    properties = next.value
                 } else currentNetwork = null
                 callbacks.toList()
-            }.forEach {
-                it.onLost()
-                newProperties?.let { prop -> it.onAvailable(prop.interfaceName!!, prop) }
-            }
+            }.forEach { it.onAvailable(properties) }
         }
     }
 
@@ -88,7 +57,7 @@ object VpnMonitor : UpstreamMonitor() {
         if (registered) {
             val currentLinkProperties = currentLinkProperties
             if (currentLinkProperties != null) GlobalScope.launch {
-                callback.onAvailable(currentLinkProperties.interfaceName!!, currentLinkProperties)
+                callback.onAvailable(currentLinkProperties)
             }
         } else {
             Services.connectivity.registerNetworkCallback(request, networkCallback)

mobile/src/main/java/be/mygod/vpnhotspot/preference/UpstreamsPreference.kt

@@ -21,32 +21,31 @@ import timber.log.Timber
 class UpstreamsPreference(context: Context, attrs: AttributeSet) : Preference(context, attrs),
         DefaultLifecycleObserver {
     companion object {
-        private val internetAddress = parseNumericAddress("8.8.8.8")
+        private val internetV4Address = parseNumericAddress("8.8.8.8")
+        private val internetV6Address = parseNumericAddress("2001:4860:4860::8888")
     }
 
-    private data class Interface(val ifname: String, val internet: Boolean = true)
     private open inner class Monitor : UpstreamMonitor.Callback {
-        protected var currentInterface: Interface? = null
-        val charSequence get() = currentInterface?.run {
+        protected var currentInterfaces = emptyMap<String, Boolean>()
+        val charSequence get() = currentInterfaces.map { (ifname, internet) ->
             if (internet) SpannableStringBuilder(ifname).apply {
                 setSpan(StyleSpan(Typeface.BOLD), 0, length, 0)
             } else ifname
-        } ?: "∅"
+        }.joinTo(SpannableStringBuilder()).let { if (it.isEmpty()) "∅" else it }
 
-        override fun onAvailable(ifname: String, properties: LinkProperties) {
-            currentInterface = Interface(ifname, properties.allRoutes.any {
-                try {
-                    it.matches(internetAddress)
+        override fun onAvailable(properties: LinkProperties?) {
+            val result = mutableMapOf<String, Boolean>()
+            for (route in properties?.allRoutes ?: emptyList()) {
+                result.compute(route.`interface` ?: continue) { _, internet ->
+                    internet == true || try {
+                        route.matches(internetV4Address) || route.matches(internetV6Address)
                     } catch (e: RuntimeException) {
                         Timber.w(e)
                         false
                     }
-            })
-            onUpdate()
                 }
-
-        override fun onLost() {
-            currentInterface = null
+            }
+            currentInterfaces = result
             onUpdate()
         }
     }
@@ -54,7 +53,7 @@ class UpstreamsPreference(context: Context, attrs: AttributeSet) : Preference(co
     private val primary = Monitor()
     private val fallback: Monitor = object : Monitor() {
         override fun onFallback() {
-            currentInterface = Interface("<default>")
+            currentInterfaces = mapOf("<default>" to true)
             onUpdate()
         }
     }