Added DNS configuration functionality. (#24)

* Changed app icon from default to Yggdrasil leaf.

* Added workaround for DNS-reslver and fix for unmetered networks.

* Added DNS configuration functionality.

* Changed DNS configuration UI. Disabled DNS config by default. Added DNS fix for Chrome-based browsers.

app/build.gradle

@@ -55,6 +55,7 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.3.0'
     implementation 'com.google.android.material:material:1.3.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
+    implementation 'androidx.preference:preference-ktx:1.1.0'
     testImplementation 'junit:junit:4.+'
     androidTestImplementation 'androidx.test.ext:junit:1.1.2'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

app/src/main/AndroidManifest.xml

@@ -16,17 +16,19 @@
             android:parentActivityName=".MainActivity" />
         <activity android:name=".PeersActivity"
             android:parentActivityName=".MainActivity" />
-        <activity android:name=".MainActivity">
+        <activity android:name=".MainActivity" android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity android:name=".DnsActivity" android:exported="false" />
 
         <service
             android:name=".PacketTunnelProvider"
-            android:permission="android.permission.BIND_VPN_SERVICE">
+            android:permission="android.permission.BIND_VPN_SERVICE"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.net.VpnService" />
             </intent-filter>

app/src/main/java/eu/neilalexander/yggdrasil/DnsActivity.kt

@@ -0,0 +1,166 @@
+package eu.neilalexander.yggdrasil
+
+import android.annotation.SuppressLint
+import android.app.AlertDialog
+import android.content.SharedPreferences
+import androidx.appcompat.app.AppCompatActivity
+import android.os.Bundle
+import android.view.ContextThemeWrapper
+import android.view.LayoutInflater
+import android.view.View
+import android.widget.*
+import com.google.android.material.textfield.TextInputEditText
+
+const val KEY_DNS_SERVERS = "dns_servers"
+const val KEY_ENABLE_CHROME_FIX = "enable_chrome_fix"
+const val DEFAULT_DNS_SERVERS = "302:7991::53,302:db60::53,300:6223::53,301:1088::53"
+
+class DnsActivity : AppCompatActivity() {
+    private lateinit var config: ConfigurationProxy
+    private lateinit var inflater: LayoutInflater
+
+    private lateinit var serversTableLayout: TableLayout
+    private lateinit var serversTableLabel: TextView
+    private lateinit var serversTableHint: TextView
+    private lateinit var addServerButton: ImageButton
+    private lateinit var enableChromeFix: Switch
+
+    private lateinit var servers: MutableList<String>
+    private lateinit var preferences: SharedPreferences
+
+    @SuppressLint("ApplySharedPref")
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_dns)
+
+        config = ConfigurationProxy(applicationContext)
+        inflater = LayoutInflater.from(this)
+
+        serversTableLayout = findViewById(R.id.configuredDnsTableLayout)
+        serversTableLabel = findViewById(R.id.configuredDnsLabel)
+        serversTableHint = findViewById(R.id.configuredDnsHint)
+        enableChromeFix = findViewById(R.id.enableChromeFix)
+
+        addServerButton = findViewById(R.id.addServerButton)
+        addServerButton.setOnClickListener {
+            val view = inflater.inflate(R.layout.dialog_add_dns_server, null)
+            val input = view.findViewById<TextInputEditText>(R.id.addDnsInput)
+            val builder: AlertDialog.Builder = AlertDialog.Builder(ContextThemeWrapper(this, R.style.Theme_MaterialComponents_DayNight_Dialog))
+            builder.setTitle(getString(R.string.dns_add_server_dialog_title))
+            builder.setView(view)
+            builder.setPositiveButton(getString(R.string.add)) { dialog, _ ->
+                servers.add(input.text.toString())
+                preferences.edit().apply {
+                    putString(KEY_DNS_SERVERS, servers.joinToString(","))
+                    commit()
+                }
+                dialog.dismiss()
+                updateConfiguredServers()
+            }
+            builder.setNegativeButton(getString(R.string.cancel)) { dialog, _ ->
+                dialog.cancel()
+            }
+            builder.show()
+        }
+
+        enableChromeFix.setOnCheckedChangeListener { _, isChecked ->
+            preferences.edit().apply {
+                putBoolean(KEY_ENABLE_CHROME_FIX, isChecked)
+                commit()
+            }
+        }
+
+        preferences = androidx.preference.PreferenceManager.getDefaultSharedPreferences(this.baseContext)
+        val serverString = preferences.getString(KEY_DNS_SERVERS, "")
+        servers = if (serverString!!.isNotEmpty()) {
+            serverString.split(",").toMutableList()
+        } else {
+            mutableListOf()
+        }
+        updateUsableServers()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        updateConfiguredServers()
+        enableChromeFix.isChecked = preferences.getBoolean(KEY_ENABLE_CHROME_FIX, false)
+    }
+
+    @SuppressLint("ApplySharedPref")
+    private fun updateConfiguredServers() {
+        when (servers.size) {
+            0 -> {
+                serversTableLayout.visibility = View.GONE
+                serversTableLabel.text = getString(R.string.dns_no_configured_servers)
+                serversTableHint.text = getText(R.string.dns_configured_servers_hint_empty)
+            }
+            else -> {
+                serversTableLayout.visibility = View.VISIBLE
+                serversTableLabel.text = getString(R.string.dns_configured_servers)
+                serversTableHint.text = getText(R.string.dns_configured_servers_hint)
+
+                serversTableLayout.removeAllViewsInLayout()
+                for (i in servers.indices) {
+                    val server = servers[i]
+                    val view = inflater.inflate(R.layout.peers_configured, null)
+                    view.findViewById<TextView>(R.id.addressValue).text = server
+                    view.findViewById<ImageButton>(R.id.deletePeerButton).tag = i
+
+                    view.findViewById<ImageButton>(R.id.deletePeerButton).setOnClickListener { button ->
+                        val builder: AlertDialog.Builder = AlertDialog.Builder(this)
+                        builder.setTitle("Remove ${server}?")
+                        builder.setPositiveButton(getString(R.string.remove)) { dialog, _ ->
+                            servers.removeAt(button.tag as Int)
+                            preferences.edit().apply {
+                                this.putString(KEY_DNS_SERVERS, servers.joinToString(","))
+                                this.commit()
+                            }
+                            dialog.dismiss()
+                            updateConfiguredServers()
+                        }
+                        builder.setNegativeButton(getString(R.string.cancel)) { dialog, _ ->
+                            dialog.cancel()
+                        }
+                        builder.show()
+                    }
+                    serversTableLayout.addView(view)
+                }
+            }
+        }
+    }
+
+    @SuppressLint("ApplySharedPref")
+    private fun updateUsableServers() {
+        val usableTableLayout: TableLayout = findViewById(R.id.usableDnsTableLayout)
+        val defaultServers = DEFAULT_DNS_SERVERS.split(",")
+
+        defaultServers.forEach {
+            val server = it
+            val view = inflater.inflate(R.layout.dns_server_usable, null)
+            view.findViewById<TextView>(R.id.serverValue).text = server
+            val addButton = view.findViewById<ImageButton>(R.id.addButton)
+            addButton.tag = server
+
+            addButton.setOnClickListener { button ->
+                servers.add(button.tag as String)
+                preferences.edit().apply {
+                    this.putString(KEY_DNS_SERVERS, servers.joinToString(","))
+                    this.commit()
+                }
+                updateConfiguredServers()
+            }
+            view.setOnLongClickListener {
+                val builder: AlertDialog.Builder = AlertDialog.Builder(this)
+                builder.setTitle(getString(R.string.dns_server_info_dialog_title))
+                builder.setMessage(getText(R.string.dns_server_info_revertron))
+                builder.setPositiveButton(getString(R.string.ok)) { dialog, _ ->
+                    dialog.dismiss()
+                }
+                builder.show()
+                true
+            }
+
+            usableTableLayout.addView(view)
+        }
+    }
+}

app/src/main/java/eu/neilalexander/yggdrasil/MainActivity.kt

@@ -27,6 +27,8 @@ class MainActivity : AppCompatActivity() {
     private lateinit var coordinatesLabel: TextView
     private lateinit var peersLabel: TextView
     private lateinit var peersRow: TableRow
+    private lateinit var dnsLabel: TextView
+    private lateinit var dnsRow: TableRow
     private lateinit var settingsRow: TableRow
 
     private fun start() {
@@ -47,13 +49,15 @@ class MainActivity : AppCompatActivity() {
 
         findViewById<TextView>(R.id.versionValue).text = Mobile.getVersion()
 
-        enabledSwitch = findViewById(R.id.enableMulticastBeacon)
+        enabledSwitch = findViewById(R.id.enableYggdrasil)
         enabledLabel = findViewById(R.id.yggdrasilStatusLabel)
         ipAddressLabel = findViewById(R.id.ipAddressValue)
         subnetLabel = findViewById(R.id.subnetValue)
         coordinatesLabel = findViewById(R.id.coordinatesValue)
         peersLabel = findViewById(R.id.peersValue)
         peersRow = findViewById(R.id.peersTableRow)
+        dnsLabel = findViewById(R.id.dnsValue)
+        dnsRow = findViewById(R.id.dnsTableRow)
         settingsRow = findViewById(R.id.settingsTableRow)
 
         enabledLabel.setTextColor(Color.GRAY)
@@ -82,6 +86,12 @@ class MainActivity : AppCompatActivity() {
             startActivity(intent)
         }
 
+        dnsRow.isClickable = true
+        dnsRow.setOnClickListener {
+            val intent = Intent(this, DnsActivity::class.java)
+            startActivity(intent)
+        }
+
         settingsRow.isClickable = true
         settingsRow.setOnClickListener {
             val intent = Intent(this, SettingsActivity::class.java)
@@ -94,6 +104,18 @@ class MainActivity : AppCompatActivity() {
         LocalBroadcastManager.getInstance(this).registerReceiver(
             receiver, IntentFilter(PacketTunnelState.RECEIVER_INTENT)
         )
+        val preferences = androidx.preference.PreferenceManager.getDefaultSharedPreferences(this.baseContext)
+        val serverString = preferences.getString(KEY_DNS_SERVERS, "")
+        if (serverString!!.isNotEmpty()) {
+            val servers = serverString.split(",")
+            dnsLabel.text = when (servers.size) {
+                0 -> "No servers"
+                1 -> "1 server"
+                else -> "${servers.size} servers"
+            }
+        } else {
+            dnsLabel.text = "No servers"
+        }
     }
 
     private val receiver: BroadcastReceiver = object : BroadcastReceiver() {

app/src/main/java/eu/neilalexander/yggdrasil/PacketTunnelProvider.kt

@@ -17,6 +17,8 @@ import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.concurrent.thread
 
 
+private const val TAG = "PacketTunnelProvider"
+
 class PacketTunnelProvider: VpnService() {
     companion object {
         const val RECEIVER_INTENT = "eu.neilalexander.yggdrasil.PacketTunnelProvider.MESSAGE"
@@ -50,16 +52,16 @@ class PacketTunnelProvider: VpnService() {
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
         if (intent == null) {
-            Log.d("PacketTunnelProvider", "Intent is null")
+            Log.d(TAG, "Intent is null")
             return START_NOT_STICKY
         }
         return when (intent.action ?: ACTION_STOP) {
             ACTION_STOP -> {
-                Log.d("PacketTunnelProvider", "Stopping...")
+                Log.d(TAG, "Stopping...")
                 stop(); START_NOT_STICKY
             }
             else -> {
-                Log.d("PacketTunnelProvider", "Starting...")
+                Log.d(TAG, "Starting...")
                 start(); START_STICKY
             }
         }
@@ -70,11 +72,11 @@ class PacketTunnelProvider: VpnService() {
             return
         }
 
-        Log.d("PacketTunnelProvider", config.getJSON().toString())
+        Log.d(TAG, config.getJSON().toString())
         yggdrasil.startJSON(config.getJSONByteArray())
 
         val address = yggdrasil.addressString
-        var builder = Builder()
+        val builder = Builder()
             .addAddress(address, 7)
             .addRoute("200::", 7)
             // We do this to trick the DNS-resolver into thinking that we have "regular" IPv6,
@@ -97,6 +99,21 @@ class PacketTunnelProvider: VpnService() {
             builder.setMetered(false)
         }
 
+        val preferences = androidx.preference.PreferenceManager.getDefaultSharedPreferences(this.baseContext)
+        val serverString = preferences.getString(KEY_DNS_SERVERS, "")
+        if (serverString!!.isNotEmpty()) {
+            val servers = serverString.split(",")
+            if (servers.isNotEmpty()) {
+                servers.forEach {
+                    Log.i(TAG, "Using DNS server $it")
+                    builder.addDnsServer(it)
+                }
+            }
+        }
+        if (preferences.getBoolean(KEY_ENABLE_CHROME_FIX, false)) {
+            builder.addRoute("2001:4860:4860::8888", 128)
+        }
+
         parcel = builder.establish()
         val parcel = parcel
         if (parcel == null || !parcel.fileDescriptor.valid()) {
@@ -123,7 +140,7 @@ class PacketTunnelProvider: VpnService() {
         intent.putExtra("ip", yggdrasil.addressString)
         intent.putExtra("subnet", yggdrasil.subnetString)
         intent.putExtra("coords", yggdrasil.coordsString)
-        intent.putExtra("peers", JSONArray(yggdrasil.peersJSON).length())
+        intent.putExtra("peers", yggdrasil.peersJSON)
         LocalBroadcastManager.getInstance(this).sendBroadcast(intent)
     }
 
@@ -214,7 +231,7 @@ class PacketTunnelProvider: VpnService() {
     }
 
     private fun reader() {
-        var b = ByteArray(65535)
+        val b = ByteArray(65535)
         reads@ while (started.get()) {
             val readerStream = readerStream
             val readerThread = readerThread

app/src/main/java/eu/neilalexander/yggdrasil/PeersActivity.kt

@@ -49,14 +49,14 @@ class PeersActivity : AppCompatActivity() {
 
         addPeerButton = findViewById(R.id.addPeerButton)
         addPeerButton.setOnClickListener {
-            var view = inflater.inflate(R.layout.dialog_addpeer, null)
+            val view = inflater.inflate(R.layout.dialog_addpeer, null)
-            var input = view.findViewById<TextInputEditText>(R.id.addPeerInput)
+            val input = view.findViewById<TextInputEditText>(R.id.addPeerInput)
             val builder: AlertDialog.Builder = AlertDialog.Builder(ContextThemeWrapper(this, R.style.Theme_MaterialComponents_DayNight_Dialog))
             builder.setTitle("Add Configured Peer")
             builder.setView(view)
             builder.setPositiveButton("Add") { dialog, _ ->
                 config.updateJSON { json ->
-                    json.getJSONArray("Peers").put(input.text)
+                    json.getJSONArray("Peers").put(input.text.toString().trim())
                 }
                 dialog.dismiss()
                 updateConfiguredPeers()
@@ -90,7 +90,7 @@ class PeersActivity : AppCompatActivity() {
                 configuredTableLayout.removeAllViewsInLayout()
                 for (i in 0 until peers.length()) {
                     val peer = peers[i].toString()
-                    var view = inflater.inflate(R.layout.peers_configured, null)
+                    val view = inflater.inflate(R.layout.peers_configured, null)
                     view.findViewById<TextView>(R.id.addressValue).text = peer
                     view.findViewById<ImageButton>(R.id.deletePeerButton).tag = i
 
@@ -130,7 +130,7 @@ class PeersActivity : AppCompatActivity() {
                 connectedTableLayout.removeAllViewsInLayout()
                 for (i in 0 until peers.length()) {
                     val peer = peers.getJSONObject(i)
-                    var view = inflater.inflate(R.layout.peers_connected, null)
+                    val view = inflater.inflate(R.layout.peers_connected, null)
                     val ip = peer.getString("IP")
                     view.findViewById<TextView>(R.id.addressLabel).text = ip
                     view.findViewById<TextView>(R.id.detailsLabel).text = peer.getString("Remote")

app/src/main/res/layout/activity_dns.xml

@@ -0,0 +1,245 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".DnsActivity">
+
+    <FrameLayout
+        android:id="@+id/settings"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:dividerPadding="4pt"
+            android:orientation="vertical">
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:id="@+id/pageTitle"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_margin="8pt"
+                    android:text="@string/dns_activity_title"
+                    android:textColor="?attr/textDefault"
+                    android:textSize="24sp"
+                    android:textStyle="bold" />
+
+                <Space
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1" />
+
+                <ImageButton
+                    android:id="@+id/addServerButton"
+                    android:layout_width="16pt"
+                    android:layout_height="16pt"
+                    android:layout_marginTop="6pt"
+                    android:layout_marginRight="8pt"
+                    android:background="@android:color/transparent"
+                    app:srcCompat="@drawable/ic_baseline_add_circle_24" />
+            </LinearLayout>
+
+            <ScrollView
+                android:layout_width="match_parent"
+                android:layout_height="match_parent">
+
+                <LinearLayout
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:orientation="vertical" >
+
+                    <TextView
+                        android:id="@+id/configuredDnsLabel"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="16pt"
+                        android:layout_marginLeft="16pt"
+                        android:layout_marginTop="8pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:layout_marginBottom="2pt"
+                        android:alpha="0.7"
+                        android:paddingRight="8pt"
+                        android:text=""
+                        android:textAllCaps="true"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textSize="12sp" />
+
+                    <TableLayout
+                        android:id="@+id/configuredDnsTableLayout"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="8pt"
+                        android:layout_marginLeft="8pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:background="@drawable/rounded"
+                        android:divider="#46878787"
+                        android:dividerPadding="4pt"
+                        android:paddingLeft="4pt"
+                        android:paddingTop="2pt"
+                        android:paddingRight="4pt"
+                        android:paddingBottom="2pt"
+                        android:showDividers="middle" />
+
+                    <TextView
+                        android:id="@+id/configuredDnsHint"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="16pt"
+                        android:layout_marginLeft="16pt"
+                        android:layout_marginTop="4pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:layout_marginBottom="4pt"
+                        android:alpha="0.7"
+                        android:paddingRight="8pt"
+                        android:text="@string/dns_configured_servers_hint"
+                        android:textAllCaps="false"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textSize="12sp" />
+
+                    <TextView
+                        android:id="@+id/usableDnsLabel"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="16pt"
+                        android:layout_marginLeft="16pt"
+                        android:layout_marginTop="8pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:layout_marginBottom="2pt"
+                        android:alpha="0.7"
+                        android:paddingRight="8pt"
+                        android:text="@string/dns_usable_servers"
+                        android:textAllCaps="true"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textSize="12sp" />
+
+                    <TableLayout
+                        android:id="@+id/usableDnsTableLayout"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="8pt"
+                        android:layout_marginLeft="8pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:background="@drawable/rounded"
+                        android:divider="#46878787"
+                        android:dividerPadding="4pt"
+                        android:paddingLeft="4pt"
+                        android:paddingTop="2pt"
+                        android:paddingRight="4pt"
+                        android:paddingBottom="2pt"
+                        android:showDividers="middle" />
+
+                    <TextView
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="16pt"
+                        android:layout_marginLeft="16pt"
+                        android:layout_marginTop="4pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:layout_marginBottom="4pt"
+                        android:alpha="0.7"
+                        android:paddingRight="8pt"
+                        android:text="@string/dns_usable_servers_hint"
+                        android:textAllCaps="false"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textSize="12sp" />
+
+                    <Space
+                        android:layout_width="match_parent"
+                        android:layout_height="32px" />
+
+                    <TextView
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="16pt"
+                        android:layout_marginLeft="16pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:layout_marginBottom="2pt"
+                        android:alpha="0.7"
+                        android:paddingRight="8pt"
+                        android:text="@string/dns_fixes"
+                        android:textAllCaps="true"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textSize="12sp" />
+
+                    <TableLayout
+                        android:id="@+id/fixesTableLayout"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="8pt"
+                        android:layout_marginLeft="8pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:background="@drawable/rounded"
+                        android:divider="#46878787"
+                        android:dividerPadding="4pt"
+                        android:paddingLeft="4pt"
+                        android:paddingTop="2pt"
+                        android:paddingRight="4pt"
+                        android:paddingBottom="2pt"
+                        android:showDividers="middle">
+
+                        <TableRow
+                            android:layout_width="match_parent"
+                            android:layout_height="match_parent"
+                            android:clickable="true"
+                            android:paddingStart="4pt"
+                            android:paddingTop="2pt"
+                            android:paddingEnd="4pt"
+                            android:paddingBottom="4pt">
+
+                            <TextView
+                                android:layout_width="wrap_content"
+                                android:layout_height="wrap_content"
+                                android:text="@string/dns_fix_chrome_based_browsers"
+                                android:textColor="?attr/textDefault" />
+
+                            <Space
+                                android:layout_width="wrap_content"
+                                android:layout_height="wrap_content"
+                                android:layout_weight="2" />
+
+                            <Switch
+                                android:id="@+id/enableChromeFix"
+                                android:layout_width="wrap_content"
+                                android:layout_height="wrap_content" />
+
+                        </TableRow>
+
+                    </TableLayout>
+
+                    <TextView
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:layout_marginStart="16pt"
+                        android:layout_marginLeft="16pt"
+                        android:layout_marginTop="4pt"
+                        android:layout_marginEnd="8pt"
+                        android:layout_marginRight="8pt"
+                        android:alpha="0.7"
+                        android:paddingRight="8pt"
+                        android:text="@string/dns_fix_chrome_based_browsers_hint"
+                        android:textAllCaps="false"
+                        android:textAppearance="@style/TextAppearance.AppCompat.Small"
+                        android:textSize="12sp" />
+
+                </LinearLayout>
+            </ScrollView>
+
+        </LinearLayout>
+    </FrameLayout>
+</LinearLayout>

app/src/main/res/layout/activity_main.xml

@@ -94,7 +94,7 @@
                                 android:layout_weight="2" />
 
                             <Switch
-                                android:id="@+id/enableMulticastBeacon"
+                                android:id="@+id/enableYggdrasil"
                                 android:layout_width="wrap_content"
                                 android:layout_height="wrap_content" />
 
@@ -347,6 +347,50 @@
                                 app:srcCompat="@drawable/ic_baseline_chevron_right_24" />
                         </TableRow>
 
+                        <TableRow
+                            android:id="@+id/dnsTableRow"
+                            android:layout_width="match_parent"
+                            android:layout_height="match_parent"
+                            android:background="?android:attr/selectableItemBackground"
+                            android:clickable="true"
+                            android:paddingStart="4pt"
+                            android:paddingTop="6pt"
+                            android:paddingEnd="4pt"
+                            android:paddingBottom="6pt">
+
+                            <TextView
+                                android:id="@+id/dnsLabel"
+                                android:layout_width="wrap_content"
+                                android:layout_height="wrap_content"
+                                android:text="DNS servers"
+                                android:textColor="?attr/textDefault" />
+
+                            <Space
+                                android:layout_width="wrap_content"
+                                android:layout_height="wrap_content"
+                                android:layout_weight="2" />
+
+                            <TextView
+                                android:id="@+id/dnsValue"
+                                android:layout_width="wrap_content"
+                                android:layout_height="wrap_content"
+                                android:alpha="0.5"
+                                android:text="No servers"
+                                android:textAlignment="textEnd" />
+
+                            <ImageView
+                                android:id="@+id/dnsChevron"
+                                android:layout_width="wrap_content"
+                                android:layout_height="match_parent"
+                                android:layout_marginLeft="2pt"
+                                android:alpha="0.4"
+                                android:cropToPadding="false"
+                                android:scaleType="fitEnd"
+                                android:scaleX="1.2"
+                                android:scaleY="1.2"
+                                app:srcCompat="@drawable/ic_baseline_chevron_right_24" />
+                        </TableRow>
+
                         <TableRow
                             android:id="@+id/settingsTableRow"
                             android:layout_width="match_parent"
@@ -426,12 +470,12 @@
                         android:layout_height="wrap_content"
                         android:layout_marginStart="16pt"
                         android:layout_marginLeft="16pt"
-                        android:layout_marginTop="2pt"
+                        android:layout_marginTop="4pt"
                         android:layout_marginEnd="8pt"
                         android:layout_marginRight="8pt"
                         android:alpha="0.7"
                         android:paddingRight="8pt"
-                        android:text="You must re-enable Yggdrasil after modifying Peers or Settings to make any changes effective."
+                        android:text="You must re-enable Yggdrasil after modifying Peers, DNS servers or Settings to make any changes effective."
                         android:textAllCaps="false"
                         android:textAppearance="@style/TextAppearance.AppCompat.Small"
                         android:textSize="12sp" />

app/src/main/res/layout/activity_peers.xml

@@ -128,7 +128,7 @@
                         android:layout_height="wrap_content"
                         android:layout_marginStart="16pt"
                         android:layout_marginLeft="16pt"
-                        android:layout_marginTop="2pt"
+                        android:layout_marginTop="4pt"
                         android:layout_marginEnd="8pt"
                         android:layout_marginRight="8pt"
                         android:layout_marginBottom="4pt"
@@ -237,7 +237,7 @@
                         android:layout_height="wrap_content"
                         android:layout_marginStart="16pt"
                         android:layout_marginLeft="16pt"
-                        android:layout_marginTop="2pt"
+                        android:layout_marginTop="4pt"
                         android:layout_marginEnd="8pt"
                         android:layout_marginRight="8pt"
                         android:alpha="0.7"

app/src/main/res/layout/dialog_add_dns_server.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:paddingLeft="10pt"
+        android:paddingTop="4pt"
+        android:paddingRight="10pt"
+        android:paddingBottom="4pt">
+
+        <TextView
+            android:id="@+id/textView2"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="Enter the IP address of DNS server to add. It will be used by OS and all apps when Yggdrasil starts." />
+
+        <com.google.android.material.textfield.TextInputLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <com.google.android.material.textfield.TextInputEditText
+                android:id="@+id/addDnsInput"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="4pt"
+                android:lines="1"
+                android:hint="8.8.8.8 or 302:7991::53" />
+        </com.google.android.material.textfield.TextInputLayout>
+    </LinearLayout>
+</FrameLayout>

app/src/main/res/layout/dialog_addpeer.xml

@@ -27,6 +27,7 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 android:layout_marginTop="4pt"
+                android:lines="1"
                 android:hint="tcp://address:port" />
         </com.google.android.material.textfield.TextInputLayout>
     </LinearLayout>

app/src/main/res/layout/dns_server_usable.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/tableRow"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <TextView
+        android:id="@+id/serverValue"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="18dp"
+        android:layout_marginTop="4dp"
+        android:layout_marginEnd="18dp"
+        android:layout_marginBottom="12dp"
+        android:ellipsize="end"
+        android:singleLine="true"
+        android:text=""
+        android:textColor="?attr/textDefault"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toStartOf="@+id/addButton"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="@+id/space" />
+
+    <Space
+        android:id="@+id/space"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        app:layout_constraintBottom_toTopOf="@+id/addButton"
+        app:layout_constraintEnd_toStartOf="@+id/addButton"
+        app:layout_constraintStart_toEndOf="@+id/serverValue"
+        app:layout_constraintTop_toTopOf="@+id/addButton" />
+
+    <ImageButton
+        android:id="@+id/addButton"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="8dp"
+        android:layout_marginEnd="4dp"
+        android:layout_marginBottom="10dp"
+        android:background="@android:color/transparent"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:srcCompat="@drawable/ic_baseline_add_circle_24" />
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/peers_configured.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
-    xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/tableRow"
     android:layout_width="match_parent"
     android:layout_height="wrap_content">
@@ -16,7 +15,7 @@
         android:layout_marginBottom="12dp"
         android:ellipsize="end"
         android:singleLine="true"
-        android:text="TextView"
+        android:text=""
         android:textColor="?attr/textDefault"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintEnd_toStartOf="@+id/deletePeerButton"

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

@@ -1,3 +1,20 @@
 <resources>
     <string name="app_name">Yggdrasil</string>
+    <string name="dns_configured_servers_hint">Yggdrasil will use these DNS servers in VPN config when service starts. All your DNS requests will be resolved by them.</string>
+    <string name="dns_configured_servers_hint_empty">Yggdrasil will not configure any DNS servers when service starts. All your DNS requests will be resolved by system resolver.</string>
+    <string name="dns_usable_servers_hint">These are DNS servers run by community members. Click plus button to add them to a list above. Long-tap to see more info.</string>
+    <string name="dns_no_configured_servers">No servers configured</string>
+    <string name="dns_configured_servers">Configured servers</string>
+    <string name="dns_server_info_revertron">The server supports resolving regular ICANN domains, ALFIS domains, OpenNIC domains.\n\nAlso, it blocks ads, analytics and malware websites.\n\nThe server is run by Revertron.</string>
+    <string name="dns_server_info_dialog_title">Server info</string>
+    <string name="ok">OK</string>
+    <string name="cancel">Cancel</string>
+    <string name="remove">Remove</string>
+    <string name="add">Add</string>
+    <string name="dns_add_server_dialog_title">Add DNS server</string>
+    <string name="dns_activity_title">DNS</string>
+    <string name="dns_usable_servers">Usable servers</string>
+    <string name="dns_fix_chrome_based_browsers">Fix Chrome-based browsers</string>
+    <string name="dns_fix_chrome_based_browsers_hint">Chrome-based browsers need an additional fix to understand that you have IPv6 connectivity.</string>
+    <string name="dns_fixes">DNS fixes</string>
 </resources>

build.gradle

@@ -1,12 +1,12 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = "1.5.0"
+    ext.kotlin_version = '1.7.20'
     repositories {
         google()
         mavenCentral()
     }
     dependencies {
-        classpath "com.android.tools.build:gradle:4.2.1"
+        classpath "com.android.tools.build:gradle:4.2.2"
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong
@@ -18,7 +18,6 @@ allprojects {
     repositories {
         google()
         mavenCentral()
-        jcenter() // Warning: this repository is going to shut down soon
     }
 }
 

readme.md

@@ -26,7 +26,7 @@ cp /tmp/yggdrasil-go/yggdrasil.aar /tmp/yggdrasil-android/app/libs/
 
 ```
 cd /tmp/yggdrasil-android
-./gradew assembleRelease
+./gradlew assembleRelease
 ```
 
 note: you will need to use jdk-11 as jdk-16 `"doesn't work" ™`