Add support for MAC and hostname rule items

app/src/main/aidl/io/nekohasekai/sfa/bg/INeighborTableCallback.aidl

@@ -0,0 +1,7 @@
+package io.nekohasekai.sfa.bg;
+
+import io.nekohasekai.sfa.bg.ParceledListSlice;
+
+interface INeighborTableCallback {
+    oneway void onNeighborTableUpdated(in ParceledListSlice entries);
+}

app/src/main/aidl/io/nekohasekai/sfa/bg/IRootService.aidl

@@ -1,6 +1,7 @@
 package io.nekohasekai.sfa.bg;
 
 import android.os.ParcelFileDescriptor;
+import io.nekohasekai.sfa.bg.INeighborTableCallback;
 import io.nekohasekai.sfa.bg.ParceledListSlice;
 
 interface IRootService {
@@ -11,4 +12,8 @@ interface IRootService {
     void installPackage(in ParcelFileDescriptor apk, long size, int userId) = 2;
 
     String exportDebugInfo(String outputPath) = 3;
+
+    void registerNeighborTableCallback(in INeighborTableCallback callback) = 4;
+
+    oneway void unregisterNeighborTableCallback(in INeighborTableCallback callback) = 5;
 }

app/src/main/aidl/io/nekohasekai/sfa/bg/NeighborEntry.aidl

@@ -0,0 +1,3 @@
+package io.nekohasekai.sfa.bg;
+
+parcelable NeighborEntry;

app/src/main/java/io/nekohasekai/sfa/bg/NeighborEntry.java

@@ -0,0 +1,49 @@
+package io.nekohasekai.sfa.bg;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+import androidx.annotation.NonNull;
+
+public class NeighborEntry implements Parcelable {
+  @NonNull public final String address;
+  @NonNull public final String macAddress;
+  @NonNull public final String hostname;
+
+  public NeighborEntry(
+      @NonNull String address, @NonNull String macAddress, @NonNull String hostname) {
+    this.address = address;
+    this.macAddress = macAddress;
+    this.hostname = hostname;
+  }
+
+  protected NeighborEntry(Parcel in) {
+    address = in.readString();
+    macAddress = in.readString();
+    hostname = in.readString();
+  }
+
+  @Override
+  public void writeToParcel(@NonNull Parcel dest, int flags) {
+    dest.writeString(address);
+    dest.writeString(macAddress);
+    dest.writeString(hostname);
+  }
+
+  @Override
+  public int describeContents() {
+    return 0;
+  }
+
+  public static final Creator<NeighborEntry> CREATOR =
+      new Creator<>() {
+        @Override
+        public NeighborEntry createFromParcel(Parcel in) {
+          return new NeighborEntry(in);
+        }
+
+        @Override
+        public NeighborEntry[] newArray(int size) {
+          return new NeighborEntry[size];
+        }
+      };
+}

app/src/main/java/io/nekohasekai/sfa/bg/PlatformInterfaceWrapper.kt

@@ -11,12 +11,16 @@ import io.nekohasekai.libbox.ConnectionOwner
 import io.nekohasekai.libbox.InterfaceUpdateListener
 import io.nekohasekai.libbox.Libbox
 import io.nekohasekai.libbox.LocalDNSTransport
+import io.nekohasekai.libbox.NeighborEntryIterator
+import io.nekohasekai.libbox.NeighborUpdateListener
 import io.nekohasekai.libbox.NetworkInterfaceIterator
 import io.nekohasekai.libbox.PlatformInterface
 import io.nekohasekai.libbox.StringIterator
 import io.nekohasekai.libbox.TunOptions
 import io.nekohasekai.libbox.WIFIState
 import io.nekohasekai.sfa.Application
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.runBlocking
 import java.net.Inet6Address
 import java.net.InetSocketAddress
 import java.net.InterfaceAddress
@@ -24,8 +28,11 @@ import java.net.NetworkInterface
 import java.security.KeyStore
 import kotlin.io.encoding.Base64
 import kotlin.io.encoding.ExperimentalEncodingApi
+import io.nekohasekai.libbox.NeighborEntry as LibboxNeighborEntry
 import io.nekohasekai.libbox.NetworkInterface as LibboxNetworkInterface
 
+private var neighborCallback: INeighborTableCallback.Stub? = null
+
 interface PlatformInterfaceWrapper : PlatformInterface {
     override fun usePlatformAutoDetectInterfaceControl(): Boolean = true
 
@@ -172,6 +179,49 @@ interface PlatformInterfaceWrapper : PlatformInterface {
         return StringArray(certificates.iterator())
     }
 
+    override fun startNeighborMonitor(listener: NeighborUpdateListener?) {
+        if (listener == null) return
+        val callback = object : INeighborTableCallback.Stub() {
+            override fun onNeighborTableUpdated(entries: ParceledListSlice<*>?) {
+                if (entries == null) return
+                @Suppress("UNCHECKED_CAST")
+                val list = entries.list as List<NeighborEntry>
+                listener.updateNeighborTable(
+                    NeighborEntryArray(
+                        list.map { entry ->
+                            LibboxNeighborEntry().apply {
+                                address = entry.address
+                                macAddress = entry.macAddress
+                                hostname = entry.hostname
+                            }
+                        }.iterator(),
+                    ),
+                )
+            }
+        }
+        neighborCallback = callback
+        runBlocking(Dispatchers.IO) {
+            RootClient.registerNeighborTableCallback(callback)
+        }
+    }
+
+    override fun registerMyInterface(name: String?) {
+    }
+
+    override fun closeNeighborMonitor(listener: NeighborUpdateListener?) {
+        val callback = neighborCallback ?: return
+        neighborCallback = null
+        runBlocking(Dispatchers.IO) {
+            RootClient.unregisterNeighborTableCallback(callback)
+        }
+    }
+
+    private class NeighborEntryArray(private val iterator: Iterator<LibboxNeighborEntry>) : NeighborEntryIterator {
+        override fun hasNext(): Boolean = iterator.hasNext()
+
+        override fun next(): LibboxNeighborEntry = iterator.next()
+    }
+
     private class InterfaceArray(private val iterator: Iterator<LibboxNetworkInterface>) : NetworkInterfaceIterator {
         override fun hasNext(): Boolean = iterator.hasNext()
 

app/src/main/java/io/nekohasekai/sfa/bg/RootClient.kt

@@ -133,4 +133,21 @@ object RootClient {
             throw e.rethrowFromSystemServer()
         }
     }
+
+    suspend fun registerNeighborTableCallback(callback: INeighborTableCallback) {
+        val svc = bindService()
+        try {
+            svc.registerNeighborTableCallback(callback)
+        } catch (e: RemoteException) {
+            throw e.rethrowFromSystemServer()
+        }
+    }
+
+    suspend fun unregisterNeighborTableCallback(callback: INeighborTableCallback) {
+        try {
+            service?.unregisterNeighborTableCallback(callback)
+        } catch (e: RemoteException) {
+            throw e.rethrowFromSystemServer()
+        }
+    }
 }

app/src/main/java/io/nekohasekai/sfa/bg/RootServer.kt

@@ -2,15 +2,36 @@ package io.nekohasekai.sfa.bg
 
 import android.content.Intent
 import android.content.pm.PackageInfo
+import android.os.Build
 import android.os.IBinder
 import android.os.ParcelFileDescriptor
+import android.os.RemoteCallbackList
+import android.util.Log
 import com.topjohnwu.superuser.ipc.RootService
+import io.nekohasekai.libbox.Libbox
+import io.nekohasekai.libbox.NeighborEntryIterator
+import io.nekohasekai.libbox.NeighborSubscription
+import io.nekohasekai.libbox.NeighborUpdateListener
 import io.nekohasekai.sfa.BuildConfig
 import io.nekohasekai.sfa.vendor.PrivilegedServiceUtils
 import java.io.IOException
+import java.lang.reflect.Proxy
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.Executors
 
 class RootServer : RootService() {
 
+    private val neighborCallbacks = RemoteCallbackList<INeighborTableCallback>()
+    private var neighborSubscription: NeighborSubscription? = null
+
+    private val hostnameByMAC = ConcurrentHashMap<String, String>()
+
+    @Volatile
+    private var lastNeighborEntries: List<Pair<String, String>>? = null
+
+    private var tetheringCallback: Any? = null
+    private var tetheringManager: Any? = null
+
     private val binder = object : IRootService.Stub() {
         override fun destroy() {
             stopSelf()
@@ -31,7 +52,174 @@ class RootServer : RootService() {
             outputPath!!,
             BuildConfig.APPLICATION_ID,
         )
+
+        override fun registerNeighborTableCallback(callback: INeighborTableCallback?) {
+            if (callback == null) return
+            neighborCallbacks.register(callback)
+            synchronized(neighborCallbacks) {
+                if (neighborSubscription == null) {
+                    try {
+                        neighborSubscription =
+                            Libbox.subscribeNeighborTable(object : NeighborUpdateListener {
+                                override fun updateNeighborTable(entries: NeighborEntryIterator?) {
+                                    if (entries == null) return
+                                    val rawList = mutableListOf<Pair<String, String>>()
+                                    while (entries.hasNext()) {
+                                        val entry = entries.next()
+                                        rawList.add(entry.address to entry.macAddress)
+                                    }
+                                    lastNeighborEntries = rawList
+                                    broadcastEnrichedEntries(rawList)
+                                }
+                            })
+                    } catch (e: Exception) {
+                        Log.e("RootServer", "subscribeNeighborTable failed", e)
+                    }
+                    startTetheringMonitor()
+                }
+            }
+        }
+
+        override fun unregisterNeighborTableCallback(callback: INeighborTableCallback?) {
+            if (callback == null) return
+            neighborCallbacks.unregister(callback)
+            synchronized(neighborCallbacks) {
+                if (neighborCallbacks.registeredCallbackCount == 0) {
+                    neighborSubscription?.close()
+                    neighborSubscription = null
+                    stopTetheringMonitor()
+                }
+            }
+        }
+    }
+
+    private fun broadcastEnrichedEntries(rawList: List<Pair<String, String>>) {
+        val list = rawList.map { (address, mac) ->
+            NeighborEntry(address, mac, hostnameByMAC[mac.uppercase()] ?: "")
+        }
+        Log.d("RootServer", "neighborTable updated: ${list.size} entries")
+        val slice = ParceledListSlice(list)
+        val count = neighborCallbacks.beginBroadcast()
+        try {
+            repeat(count) { i ->
+                try {
+                    neighborCallbacks.getBroadcastItem(i).onNeighborTableUpdated(slice)
+                } catch (_: Exception) {
+                }
+            }
+        } finally {
+            neighborCallbacks.finishBroadcast()
+        }
+    }
+
+    // TetheringManager reflection (API 30+)
+
+    private val classTetheredClient by lazy {
+        Class.forName("android.net.TetheredClient")
+    }
+    private val getMacAddress by lazy {
+        classTetheredClient.getDeclaredMethod("getMacAddress")
+    }
+    private val getAddresses by lazy {
+        classTetheredClient.getDeclaredMethod("getAddresses")
+    }
+    private val classAddressInfo by lazy {
+        Class.forName("android.net.TetheredClient\$AddressInfo")
+    }
+    private val getHostname by lazy {
+        classAddressInfo.getDeclaredMethod("getHostname")
+    }
+
+    private fun startTetheringMonitor() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R) return
+        try {
+            val manager = getSystemService("tethering") ?: return
+            tetheringManager = manager
+            val callbackClass =
+                Class.forName("android.net.TetheringManager\$TetheringEventCallback")
+            val registerMethod = manager.javaClass.getMethod(
+                "registerTetheringEventCallback",
+                java.util.concurrent.Executor::class.java,
+                callbackClass,
+            )
+            val proxy = Proxy.newProxyInstance(
+                callbackClass.classLoader,
+                arrayOf(callbackClass),
+            ) { proxyObject, method, args ->
+                when (method.name) {
+                    "hashCode" -> System.identityHashCode(proxyObject)
+                    "equals" -> proxyObject === args?.get(0)
+                    "toString" ->
+                        proxyObject.javaClass.name + "@" +
+                            Integer.toHexString(System.identityHashCode(proxyObject))
+                    "onClientsChanged" -> {
+                        if (args != null) {
+                            @Suppress("UNCHECKED_CAST")
+                            handleClientsChanged(args[0] as Collection<*>)
+                        }
+                        null
+                    }
+                    else -> null
+                }
+            }
+            tetheringCallback = proxy
+            registerMethod.invoke(manager, Executors.newSingleThreadExecutor(), proxy)
+            Log.d("RootServer", "TetheringManager monitor started")
+        } catch (e: Exception) {
+            Log.e("RootServer", "startTetheringMonitor failed", e)
+        }
+    }
+
+    private fun stopTetheringMonitor() {
+        val manager = tetheringManager ?: return
+        val callback = tetheringCallback ?: return
+        try {
+            val callbackClass =
+                Class.forName("android.net.TetheringManager\$TetheringEventCallback")
+            val unregisterMethod = manager.javaClass.getMethod(
+                "unregisterTetheringEventCallback",
+                callbackClass,
+            )
+            unregisterMethod.invoke(manager, callback)
+        } catch (e: Exception) {
+            Log.e("RootServer", "stopTetheringMonitor failed", e)
+        }
+        tetheringCallback = null
+        tetheringManager = null
+        hostnameByMAC.clear()
+    }
+
+    private fun handleClientsChanged(clients: Collection<*>) {
+        hostnameByMAC.clear()
+        for (client in clients) {
+            if (client == null) continue
+            try {
+                val mac = getMacAddress.invoke(client).toString().uppercase()
+
+                @Suppress("UNCHECKED_CAST")
+                val addresses = getAddresses.invoke(client) as List<*>
+                for (info in addresses) {
+                    if (info == null) continue
+                    val hostname = getHostname.invoke(info) as? String
+                    if (!hostname.isNullOrEmpty()) {
+                        hostnameByMAC[mac] = hostname
+                    }
+                }
+            } catch (e: Exception) {
+                Log.e("RootServer", "handleClientsChanged reflection error", e)
+            }
+        }
+        Log.d("RootServer", "tethered clients updated: ${hostnameByMAC.size} hostnames")
+        lastNeighborEntries?.let { broadcastEnrichedEntries(it) }
     }
 
     override fun onBind(intent: Intent): IBinder = binder
+
+    override fun onDestroy() {
+        stopTetheringMonitor()
+        neighborSubscription?.close()
+        neighborSubscription = null
+        neighborCallbacks.kill()
+        super.onDestroy()
+    }
 }