From 7e08cfa9a576d8176083efc484f7d7a0fc894151 Mon Sep 17 00:00:00 2001
From: Revertron <rev@revertron.com>
Date: Wed, 9 Nov 2022 14:05:59 +0100
Subject: [PATCH] Made fast reconnect when network becomes up. Added sending
 local IPs to multicast module.

---
 app/src/main/AndroidManifest.xml              |  1 +
 .../yggdrasil/GlobalApplication.kt            |  1 +
 .../yggdrasil/NetworkStateCallback.kt         | 43 +++++++++++++++++++
 .../yggdrasil/PacketTunnelProvider.kt         | 37 ++++++++++++++++
 4 files changed, 82 insertions(+)
 create mode 100644 app/src/main/java/eu/neilalexander/yggdrasil/NetworkStateCallback.kt

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 9a1557c..edec37d 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -3,6 +3,7 @@
     package="eu.neilalexander.yggdrasil">
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.CHANGE_WIFI_MULTICAST_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 
     <application
         android:name=".GlobalApplication"
diff --git a/app/src/main/java/eu/neilalexander/yggdrasil/GlobalApplication.kt b/app/src/main/java/eu/neilalexander/yggdrasil/GlobalApplication.kt
index 13fedff..58cda01 100644
--- a/app/src/main/java/eu/neilalexander/yggdrasil/GlobalApplication.kt
+++ b/app/src/main/java/eu/neilalexander/yggdrasil/GlobalApplication.kt
@@ -9,6 +9,7 @@ class GlobalApplication: Application() {
     override fun onCreate() {
         super.onCreate()
         config = ConfigurationProxy(applicationContext)
+        val callback = NetworkStateCallback(this)
     }
 
     fun subscribe() {
diff --git a/app/src/main/java/eu/neilalexander/yggdrasil/NetworkStateCallback.kt b/app/src/main/java/eu/neilalexander/yggdrasil/NetworkStateCallback.kt
new file mode 100644
index 0000000..97c214c
--- /dev/null
+++ b/app/src/main/java/eu/neilalexander/yggdrasil/NetworkStateCallback.kt
@@ -0,0 +1,43 @@
+package eu.neilalexander.yggdrasil
+
+import android.content.Context
+import android.content.Intent
+import android.net.*
+import android.util.Log
+import java.net.NetworkInterface
+import java.util.*
+
+
+private const val TAG = "Network"
+
+class NetworkStateCallback(val context: Context) : ConnectivityManager.NetworkCallback() {
+
+    init {
+        val request = NetworkRequest.Builder()
+            .addTransportType(NetworkCapabilities.TRANSPORT_WIFI)
+            .addTransportType(NetworkCapabilities.TRANSPORT_CELLULAR)
+            .addTransportType(NetworkCapabilities.TRANSPORT_ETHERNET)
+            .build()
+
+        val manager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+        manager.registerNetworkCallback(request, this)
+    }
+
+    override fun onAvailable(network: Network) {
+        super.onAvailable(network)
+        Log.d(TAG, "onAvailable")
+
+        Thread {
+            // The message often arrives before the connection is fully established
+            Thread.sleep(1000)
+            val intent = Intent(context, PacketTunnelProvider::class.java)
+            intent.action = PacketTunnelProvider.ACTION_CONNECT
+            context.startService(intent)
+        }.start()
+    }
+
+    override fun onLost(network: Network) {
+        super.onLost(network)
+        Log.d(TAG, "onLost")
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/eu/neilalexander/yggdrasil/PacketTunnelProvider.kt b/app/src/main/java/eu/neilalexander/yggdrasil/PacketTunnelProvider.kt
index d9a3af7..4db71b1 100644
--- a/app/src/main/java/eu/neilalexander/yggdrasil/PacketTunnelProvider.kt
+++ b/app/src/main/java/eu/neilalexander/yggdrasil/PacketTunnelProvider.kt
@@ -9,6 +9,8 @@ import androidx.localbroadcastmanager.content.LocalBroadcastManager
 import mobile.Yggdrasil
 import java.io.FileInputStream
 import java.io.FileOutputStream
+import java.net.NetworkInterface
+import java.util.*
 import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.concurrent.thread
 
@@ -21,6 +23,7 @@ class PacketTunnelProvider: VpnService() {
 
         const val ACTION_START = "eu.neilalexander.yggdrasil.PacketTunnelProvider.START"
         const val ACTION_STOP = "eu.neilalexander.yggdrasil.PacketTunnelProvider.STOP"
+        const val ACTION_CONNECT = "eu.neilalexander.yggdrasil.PacketTunnelProvider.CONNECT"
     }
 
     private var yggdrasil = Yggdrasil()
@@ -56,6 +59,10 @@ class PacketTunnelProvider: VpnService() {
                 Log.d(TAG, "Stopping...")
                 stop(); START_NOT_STICKY
             }
+            ACTION_CONNECT -> {
+                Log.d(TAG, "Connecting...")
+                connect(); START_STICKY
+            }
             else -> {
                 Log.d(TAG, "Starting...")
                 start(); START_STICKY
@@ -181,6 +188,14 @@ class PacketTunnelProvider: VpnService() {
         stopSelf()
     }
 
+    private fun connect() {
+        if (!started.get()) {
+            return
+        }
+        yggdrasil.setMulticastInterfaces(getInterfaces().joinToString("\n"))
+        yggdrasil.connectAnyPeer()
+    }
+
     private fun updater() {
         updates@ while (started.get()) {
             if ((application as  GlobalApplication).needUiUpdates()) {
@@ -260,4 +275,26 @@ class PacketTunnelProvider: VpnService() {
             readerStream = null
         }
     }
+
+    private fun getInterfaces(): Array<String> {
+        val result = ArrayList<String>()
+
+        val interfaces: List<NetworkInterface> = try {
+            Collections.list(NetworkInterface.getNetworkInterfaces())
+        } catch (e: java.lang.Exception) {
+            return result.toTypedArray()
+        }
+
+        for (i in interfaces) {
+            if (!i.isUp) continue
+
+            if (i.supportsMulticast() && !i.isPointToPoint) {
+                for (addr in i.inetAddresses) {
+                    val a = addr.toString().replace("/", "")
+                    result.add("${i.name}|${a}")
+                }
+            }
+        }
+        return result.toTypedArray()
+    }
 }
\ No newline at end of file