1. added DNS form. iteration 1.

app/src/main/AndroidManifest.xml

@@ -18,7 +18,10 @@
                 android:name=".PeerListActivity"
                 android:label="@string/title_activity_peer_list"
                 android:theme="@style/AppTheme.NoActionBar" />
-
+        <activity
+                android:name=".DNSListActivity"
+                android:label="@string/title_activity_dns_list"
+                android:theme="@style/AppTheme.NoActionBar" />
         <service
                 android:name=".YggdrasilTunService"
                 android:enabled="true"

app/src/main/java/io/github/chronosx88/yggdrasil/DNSListActivity.kt

@@ -0,0 +1,109 @@
+package io.github.chronosx88.yggdrasil
+
+import android.app.Activity
+import android.content.Intent
+import android.os.Bundle
+import android.view.Gravity
+import android.view.Menu
+import android.view.MenuItem
+import android.widget.Button
+import android.widget.ListView
+import android.widget.Toast
+import androidx.appcompat.app.AppCompatActivity
+import com.google.android.material.floatingactionbutton.FloatingActionButton
+import com.google.android.material.snackbar.Snackbar
+import io.github.chronosx88.yggdrasil.models.DNSInfo
+import io.github.chronosx88.yggdrasil.models.config.SelectDNSInfoListAdapter
+import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.ping
+import kotlinx.coroutines.*
+import java.net.*
+import kotlin.concurrent.thread
+
+
+class DNSListActivity : AppCompatActivity() {
+
+    companion object {
+        val allDNS = arrayListOf(
+            DNSInfo(
+            InetAddress.getByName("[301:2522::53]"),
+            "CZ",
+            "DNS implementation for Yggdrasil. https://github.com/Revertron/wyrd"),
+            DNSInfo(InetAddress.getByName("[301:2923::53]"),
+            "SK",
+            "DNS implementation for Yggdrasil. https://github.com/Revertron/wyrd"),
+            DNSInfo(InetAddress.getByName("[300:4523::53]"),
+                "DE",
+                "DNS implementation for Yggdrasil. https://github.com/Revertron/wyrd"),
+            DNSInfo(InetAddress.getByName("[303:8b1a::53]"),
+            "RU",
+            "DNS implementation for Yggdrasil. https://github.com/Revertron/wyrd")
+        )
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_dns_list)
+        setSupportActionBar(findViewById(R.id.toolbar))
+        findViewById<FloatingActionButton>(R.id.fab).setOnClickListener { view ->
+            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
+                .setAction("Action", null).show()
+        }
+        var extras = intent.extras
+        var dnsList = findViewById<ListView>(R.id.dnsList)
+        var adapter = SelectDNSInfoListAdapter(this, arrayListOf(), mutableSetOf())
+        dnsList.adapter = adapter
+        thread(start = true) {
+            try {
+                var cd = MainActivity.deserializeStringList2DNSInfoSet(
+                    extras!!.getStringArrayList(MainActivity.DNS_LIST)!!
+                )
+                for (d in cd) {
+                    var ping = ping(d.address, 53)
+                    d.ping = ping
+                }
+                for (dns in allDNS) {
+                    if (cd.contains(dns)) {
+                        continue
+                    }
+                    var ping = ping(dns.address, 53)
+                    dns.ping = ping
+                    adapter.addItem(dns)
+                    runOnUiThread(
+                        Runnable
+                        {
+                            adapter.sort()
+                        }
+                    )
+                }
+            } catch (e: Throwable) {
+                e.printStackTrace()
+            }
+        }
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu): Boolean {
+        // Inflate the menu; this adds items to the action bar if it is present.
+        menuInflater.inflate(R.menu.save, menu)
+        val item = menu.findItem(R.id.saveItem) as MenuItem
+        item.setActionView(R.layout.menu_save)
+        val saveButton = item
+            .actionView.findViewById<Button>(R.id.saveButton)
+        saveButton.setOnClickListener {
+            val result = Intent(this, MainActivity::class.java)
+            var adapter = findViewById<ListView>(R.id.dnsList).adapter as SelectDNSInfoListAdapter
+            val selectedDNS = adapter.getSelectedDNS()
+            if(selectedDNS.size>0) {
+                result.putExtra(MainActivity.DNS_LIST, MainActivity.serializeDNSInfoSet2StringList(selectedDNS))
+                setResult(Activity.RESULT_OK, result)
+                finish()
+            } else {
+                val text = "Select at least one DNS"
+                val duration = Toast.LENGTH_SHORT
+                val toast = Toast.makeText(applicationContext, text, duration)
+                toast.setGravity(Gravity.CENTER, 0, 0)
+                toast.show()
+            }
+        }
+        return true
+    }
+}

app/src/main/java/io/github/chronosx88/yggdrasil/MainActivity.kt

@@ -13,7 +13,9 @@ import android.widget.*
 import androidx.appcompat.app.AppCompatActivity
 import androidx.preference.PreferenceManager
 import com.google.gson.Gson
+import io.github.chronosx88.yggdrasil.models.DNSInfo
 import io.github.chronosx88.yggdrasil.models.PeerInfo
+import io.github.chronosx88.yggdrasil.models.config.DNSInfoListAdapter
 import io.github.chronosx88.yggdrasil.models.config.PeerInfoListAdapter
 import kotlin.collections.ArrayList
 import kotlin.collections.HashSet
@@ -31,9 +33,13 @@ class MainActivity : AppCompatActivity() {
         const val STATUS_STOP = 9
         const val IPv6: String = "IPv6"
         const val PEERS: String = "PEERS"
+        const val DNS: String = "DNS"
         const val PEER_LIST_CODE = 1000
+        const val DNS_LIST_CODE = 2000
         const val PEER_LIST = "PEERS_LIST"
+        const val DNS_LIST = "DNS_LIST"
         const val CURRENT_PEERS = "CURRENT_PEERS_v1.1"
+        const val CURRENT_DNS = "CURRENT_DNS_v1.1"
         const val START_VPN = "START_VPN"
         private const val TAG="Yggdrasil"
         private const val VPN_REQUEST_CODE = 0x0F
@@ -48,6 +54,16 @@ class MainActivity : AppCompatActivity() {
             return out
         }
 
+        @JvmStatic
+        fun deserializeStringList2DNSInfoSet(list: List<String>): MutableSet<DNSInfo> {
+            var gson = Gson()
+            var out = mutableSetOf<DNSInfo>()
+            for(s in list) {
+                out.add(gson.fromJson(s, DNSInfo::class.java))
+            }
+            return out
+        }
+
         @JvmStatic
         fun deserializeStringSet2PeerInfoSet(list: Set<String>): MutableSet<PeerInfo> {
             var gson = Gson()
@@ -58,6 +74,16 @@ class MainActivity : AppCompatActivity() {
             return out
         }
 
+        @JvmStatic
+        fun deserializeStringSet2DNSInfoSet(list: Set<String>): MutableSet<DNSInfo> {
+            var gson = Gson()
+            var out = mutableSetOf<DNSInfo>()
+            for(s in list) {
+                out.add(gson.fromJson(s, DNSInfo::class.java))
+            }
+            return out
+        }
+
         @JvmStatic
         fun serializePeerInfoSet2StringList(list: Set<PeerInfo>): ArrayList<String> {
             var gson = Gson()
@@ -67,10 +93,21 @@ class MainActivity : AppCompatActivity() {
             }
             return out
         }
+
+        @JvmStatic
+        fun serializeDNSInfoSet2StringList(list: Set<DNSInfo>): ArrayList<String> {
+            var gson = Gson()
+            var out = ArrayList<String>()
+            for(p in list) {
+                out.add(gson.toJson(p))
+            }
+            return out
+        }
     }
 
     private var startVpnFlag = false
     private var currentPeers = setOf<PeerInfo>()
+    private var currentDNS = setOf<DNSInfo>()
     private var isStarted = false
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -82,7 +119,7 @@ class MainActivity : AppCompatActivity() {
             PreferenceManager.getDefaultSharedPreferences(this.baseContext)
         currentPeers = deserializeStringSet2PeerInfoSet(preferences.getStringSet(CURRENT_PEERS, HashSet())!!)
 
-        val adapter = PeerInfoListAdapter(this, ArrayList(currentPeers))
+        val adapter = PeerInfoListAdapter(this, currentPeers.sortedWith(compareBy { it.ping }))
         listView.adapter = adapter
         val editPeersButton = findViewById<Button>(R.id.edit)
         editPeersButton.setOnClickListener {
@@ -90,10 +127,25 @@ class MainActivity : AppCompatActivity() {
                 showToast("Service is running. Please stop service before edit Peers list")
                 return@setOnClickListener
             }
-            val intent = Intent(this, PeerListActivity::class.java)
+            val intent = Intent(this@MainActivity, PeerListActivity::class.java)
             intent.putStringArrayListExtra(PEER_LIST, serializePeerInfoSet2StringList(currentPeers))
             startActivityForResult(intent, PEER_LIST_CODE)
         }
+
+        val listViewDNS = findViewById<ListView>(R.id.dns)
+        currentDNS = deserializeStringSet2DNSInfoSet(preferences.getStringSet(CURRENT_DNS, HashSet())!!)
+        val adapterDns = DNSInfoListAdapter(this, currentDNS.sortedWith(compareBy { it.ping }))
+        listViewDNS.adapter = adapterDns
+        val editDnsButton = findViewById<Button>(R.id.editDNS)
+        editDnsButton.setOnClickListener {
+            if(!isStarted){
+                showToast("Service is not running. DNS ping will not be run")
+                return@setOnClickListener
+            }
+            val intent = Intent(this@MainActivity, DNSListActivity::class.java)
+            intent.putStringArrayListExtra(DNS_LIST, serializeDNSInfoSet2StringList(currentDNS))
+            startActivityForResult(intent, DNS_LIST_CODE)
+        }
         if(intent.extras!==null) {
             startVpnFlag = intent.extras!!.getBoolean(START_VPN, false)
         }
@@ -123,6 +175,7 @@ class MainActivity : AppCompatActivity() {
 
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         super.onActivityResult(requestCode, resultCode, data)
+
         if (requestCode == VPN_REQUEST_CODE && resultCode== Activity.RESULT_OK){
             if(currentPeers.isEmpty()){
                 showToast("No peers selected!")
@@ -134,8 +187,10 @@ class MainActivity : AppCompatActivity() {
             intent.putExtra(PARAM_PINTENT, pi)
             intent.putExtra(COMMAND, START)
             intent.putStringArrayListExtra(PEERS, serializePeerInfoSet2StringList(currentPeers))
+            intent.putStringArrayListExtra(DNS, serializeDNSInfoSet2StringList(currentDNS))
             startService(intent)
         }
+
         if (requestCode == PEER_LIST_CODE && resultCode== Activity.RESULT_OK){
             if(data!!.extras!=null){
                 var currentPeers = data.extras!!.getStringArrayList(PEER_LIST)
@@ -152,7 +207,7 @@ class MainActivity : AppCompatActivity() {
                         PreferenceManager.getDefaultSharedPreferences(this.baseContext)
                     preferences.edit().putStringSet(CURRENT_PEERS, HashSet(currentPeers)).apply()
                     if(isStarted){
-                        //TODO implement UpdateConfig methon in native interface and apply peer changes
+                        //TODO implement UpdateConfig method in native interface and apply peer changes
                         stopVpn()
                         val i = baseContext.packageManager
                             .getLaunchIntentForPackage(baseContext.packageName)
@@ -165,6 +220,36 @@ class MainActivity : AppCompatActivity() {
                 }
             }
         }
+
+        if (requestCode == DNS_LIST_CODE && resultCode== Activity.RESULT_OK){
+            if(data!!.extras!=null){
+                var currentDNS = data.extras!!.getStringArrayList(DNS_LIST)
+                if(currentDNS==null || currentDNS.size==0){
+                    showToast("No DNS selected!")
+                } else {
+                    this.currentDNS = deserializeStringList2DNSInfoSet(currentDNS)
+                    val adapter = DNSInfoListAdapter(this, this.currentDNS.sortedWith(compareBy { it.ping }))
+                    val listView = findViewById<ListView>(R.id.dns)
+                    listView.adapter = adapter
+                    //save to shared preferences
+                    val preferences =
+                        PreferenceManager.getDefaultSharedPreferences(this.baseContext)
+                    preferences.edit().putStringSet(CURRENT_DNS, HashSet(currentDNS)).apply()
+                    if(isStarted){
+                        //TODO implement UpdateConfig method in native interface and apply peer changes
+                        stopVpn()
+                        val i = baseContext.packageManager
+                            .getLaunchIntentForPackage(baseContext.packageName)
+                        i!!.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
+                        i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+                        i.putExtra(START_VPN, true)
+                        finish()
+                        startActivity(i)
+                    }
+                }
+            }
+        }
+
         when (resultCode) {
             STATUS_START -> print("service started")
             STATUS_FINISH -> {

app/src/main/java/io/github/chronosx88/yggdrasil/PeerListActivity.kt

@@ -18,6 +18,7 @@ import com.hbb20.CCPCountry
 import io.github.chronosx88.yggdrasil.models.PeerInfo
 import io.github.chronosx88.yggdrasil.models.Status
 import io.github.chronosx88.yggdrasil.models.config.SelectPeerInfoListAdapter
+import io.github.chronosx88.yggdrasil.models.config.Utils.Companion.ping
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
@@ -44,19 +45,6 @@ class PeerListActivity : AppCompatActivity() {
         }
     }
 
-    fun ping(address: InetAddress, port:Int): Int {
-        val start = System.currentTimeMillis()
-        val socket = Socket()
-        try {
-            socket.connect(InetSocketAddress(address, port), 5000)
-            socket.close()
-        } catch (e: Exception) {
-            //silently pass
-            return Int.MAX_VALUE
-        }
-        return (System.currentTimeMillis() - start).toInt()
-    }
-
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_peer_list)
@@ -67,8 +55,7 @@ class PeerListActivity : AppCompatActivity() {
         }
         var extras = intent.extras
         var peerList = findViewById<ListView>(R.id.peerList)
-        var allPeers = arrayListOf<PeerInfo>()
+        var adapter = SelectPeerInfoListAdapter(this, arrayListOf(), mutableSetOf())
-        var adapter = SelectPeerInfoListAdapter(this, allPeers, mutableSetOf())
         peerList.adapter = adapter
 
         GlobalScope.launch {
@@ -103,7 +90,7 @@ class PeerListActivity : AppCompatActivity() {
                                         var ping = ping(address, url.port)
                                         peerInfo.ping = ping
                                         adapter.addItem(peerInfo)
-                                        if(peerList.adapter.count % 5 == 0) {
+                                        if(adapter.count % 5 == 0) {
                                             withContext(Dispatchers.Main) {
                                                 adapter.sort()
                                             }
@@ -128,7 +115,7 @@ class PeerListActivity : AppCompatActivity() {
 
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         // Inflate the menu; this adds items to the action bar if it is present.
-        menuInflater.inflate(R.menu.save_peers, menu)
+        menuInflater.inflate(R.menu.save, menu)
         val item = menu.findItem(R.id.saveItem) as MenuItem
         item.setActionView(R.layout.menu_save)
         val saveButton = item

app/src/main/java/io/github/chronosx88/yggdrasil/YggdrasilTunService.kt

@@ -7,6 +7,7 @@ import android.os.ParcelFileDescriptor
 import android.system.OsConstants
 import com.google.gson.Gson
 import dummy.ConduitEndpoint
+import io.github.chronosx88.yggdrasil.models.DNSInfo
 import io.github.chronosx88.yggdrasil.models.PeerInfo
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.cancel
@@ -53,18 +54,21 @@ class YggdrasilTunService : VpnService() {
         }
         if (intent?.getStringExtra(MainActivity.COMMAND) == MainActivity.START) {
             val peers = MainActivity.deserializeStringList2PeerInfoSet(intent.getStringArrayListExtra(MainActivity.PEERS))
+            val dns = MainActivity.deserializeStringList2DNSInfoSet(intent.getStringArrayListExtra(MainActivity.DNS))
             val pi: PendingIntent = intent.getParcelableExtra(MainActivity.PARAM_PINTENT)
             ygg = Yggdrasil()
-            setupTunInterface(pi, peers)
+            setupTunInterface(pi, peers, dns)
         }
 
         return super.onStartCommand(intent, flags, startId)
     }
 
-    private fun setupTunInterface(pi: PendingIntent, peers: Set<PeerInfo>) {
+    private fun setupTunInterface(
+        pi: PendingIntent,
+        peers: Set<PeerInfo>,
+        dns: MutableSet<DNSInfo>
+    ) {
         pi.send(MainActivity.STATUS_START)
-        val builder = Builder()
-
         var configJson = Mobile.generateConfigJSON()
         val gson = Gson()
         var config = gson.fromJson(String(configJson), Map::class.java).toMutableMap()
@@ -74,12 +78,16 @@ class YggdrasilTunService : VpnService() {
         yggConduitEndpoint = ygg.startJSON(configJson)
         val address = ygg.addressString // hack for getting generic ipv6 string from NodeID
 
-        tunInterface = builder
+        var builder = Builder()
             .addAddress(address, 7)
             .allowFamily(OsConstants.AF_INET)
             .setMtu(MAX_PACKET_SIZE)
-            .establish()
+        if(dns.size>0){
-
+            for (d in dns){
+                builder.addDnsServer(d.address)
+            }
+        }
+        tunInterface = builder.establish()
         tunInputStream = FileInputStream(tunInterface!!.fileDescriptor)
         tunOutputStream = FileOutputStream(tunInterface!!.fileDescriptor)
         readCoroutine = GlobalScope.launch {

app/src/main/java/io/github/chronosx88/yggdrasil/models/DNSInfo.kt

@@ -0,0 +1,34 @@
+package io.github.chronosx88.yggdrasil.models
+
+import android.content.Context
+import com.hbb20.CCPCountry
+import com.hbb20.CountryCodePicker
+import java.net.InetAddress
+
+
+class DNSInfo {
+
+    constructor(address: InetAddress, countryCode: String, description: String){
+        this.address = address
+        this.countryCode = countryCode
+        this.description = description
+    }
+
+    var address: InetAddress
+    var countryCode: String
+    var description: String
+    var ping: Int = Int.MAX_VALUE
+
+    override fun toString(): String {
+        return "[" + address.toString().substring(1) + "]"
+    }
+
+    override fun equals(other: Any?): Boolean {
+        return toString() == other.toString()
+    }
+
+    fun getCountry(context: Context): CCPCountry? {
+        return CCPCountry.getCountryForNameCodeFromLibraryMasterList(context, CountryCodePicker.Language.ENGLISH, countryCode)
+    }
+
+}

app/src/main/java/io/github/chronosx88/yggdrasil/models/config/DNSInfoListAdapter.kt

@@ -0,0 +1,44 @@
+package io.github.chronosx88.yggdrasil.models.config
+
+import android.content.Context
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ArrayAdapter
+import android.widget.ImageView
+import android.widget.TextView
+import io.github.chronosx88.yggdrasil.R
+import io.github.chronosx88.yggdrasil.models.DNSInfo
+
+
+class DNSInfoListAdapter(
+    context: Context,
+    allDNS: List<DNSInfo>
+) : ArrayAdapter<DNSInfo?> (context, 0, allDNS) {
+
+    private val mContext: Context = context
+    private var allDNS: List<DNSInfo> = allDNS
+
+    override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
+        var dnsInfoHolder = DNSInfoHolder()
+        var listItem: View? = convertView
+        if (listItem == null) {
+            listItem = LayoutInflater.from(mContext).inflate(R.layout.host_list_item, parent, false)
+            dnsInfoHolder.countryFlag = listItem.findViewById(R.id.countryFlag) as ImageView
+            dnsInfoHolder.dnsInfoText = listItem.findViewById(R.id.hostInfoText) as TextView
+            listItem.tag = dnsInfoHolder
+        } else {
+            dnsInfoHolder = listItem.tag as DNSInfoHolder
+        }
+        val currentDNS = allDNS[position]
+        dnsInfoHolder.countryFlag.setImageResource(currentDNS.getCountry(mContext)!!.flagID)
+        dnsInfoHolder.dnsInfoText.text = currentDNS.toString()
+        return listItem!!
+    }
+
+    class DNSInfoHolder {
+        lateinit var countryFlag: ImageView
+        lateinit var dnsInfoText: TextView
+    }
+
+}

app/src/main/java/io/github/chronosx88/yggdrasil/models/config/PeerInfoListAdapter.kt

@@ -5,12 +5,10 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.ArrayAdapter
-import android.widget.CheckBox
 import android.widget.ImageView
 import android.widget.TextView
 import io.github.chronosx88.yggdrasil.R
 import io.github.chronosx88.yggdrasil.models.PeerInfo
-import java.util.ArrayList
 
 
 class PeerInfoListAdapter(
@@ -25,17 +23,16 @@ class PeerInfoListAdapter(
         var peerInfoHolder = PeerInfoHolder()
         var listItem: View? = convertView
         if (listItem == null) {
-            listItem = LayoutInflater.from(mContext).inflate(R.layout.peers_list_item, parent, false)
+            listItem = LayoutInflater.from(mContext).inflate(R.layout.host_list_item, parent, false)
             peerInfoHolder.countryFlag = listItem.findViewById(R.id.countryFlag) as ImageView
-            peerInfoHolder.peerInfoText = listItem.findViewById(R.id.peerInfoText) as TextView
+            peerInfoHolder.peerInfoText = listItem.findViewById(R.id.hostInfoText) as TextView
             listItem.tag = peerInfoHolder
         } else {
             peerInfoHolder = listItem.tag as PeerInfoHolder
         }
         val currentPeer = allPeers[position]
         peerInfoHolder.countryFlag.setImageResource(currentPeer.getCountry(mContext)!!.flagID)
-        val peerId = currentPeer.toString()
+        peerInfoHolder.peerInfoText.text = currentPeer.toString()
-        peerInfoHolder.peerInfoText.text = peerId
         return listItem!!
     }
 

app/src/main/java/io/github/chronosx88/yggdrasil/models/config/SelectDNSInfoAdapter.kt

@@ -0,0 +1,99 @@
+package io.github.chronosx88.yggdrasil.models.config
+
+import android.content.Context
+import android.graphics.Color
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ArrayAdapter
+import android.widget.CheckBox
+import android.widget.ImageView
+import android.widget.TextView
+import io.github.chronosx88.yggdrasil.R
+import io.github.chronosx88.yggdrasil.models.DNSInfo
+
+class SelectDNSInfoListAdapter(
+    context: Context,
+    allDNS: List<DNSInfo>,
+    currentDNS: MutableSet<DNSInfo>
+) : ArrayAdapter<DNSInfo?> (context, 0, allDNS) {
+
+    private val mContext: Context = context
+    private var allDNS: MutableList<DNSInfo> = allDNS as MutableList<DNSInfo>
+    private var currentDNS: MutableSet<DNSInfo> = currentDNS
+
+    override fun getItem(position: Int): DNSInfo? {
+        return allDNS.get(position)
+    }
+
+    override fun getCount(): Int {
+        return allDNS.size
+    }
+
+    override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
+        var dnsInfoHolder = DNSInfoHolder()
+        var listItem: View? = convertView
+        if (listItem == null) {
+            listItem = LayoutInflater.from(mContext).inflate(R.layout.host_list_item_edit, parent, false)
+            dnsInfoHolder.checkbox = listItem.findViewById(R.id.checkbox) as CheckBox
+            dnsInfoHolder.countryFlag = listItem.findViewById(R.id.countryFlag) as ImageView
+            dnsInfoHolder.dnsInfoText = listItem.findViewById(R.id.hostInfoText) as TextView
+            dnsInfoHolder.ping = listItem.findViewById(R.id.ping) as TextView
+            listItem.tag = dnsInfoHolder
+        } else {
+            dnsInfoHolder = listItem.tag as DNSInfoHolder
+        }
+        val currentDNS = allDNS[position]
+        dnsInfoHolder.countryFlag.setImageResource(currentDNS.getCountry(mContext)!!.flagID)
+        val dnsId = currentDNS.toString()
+        if(currentDNS.ping == Int.MAX_VALUE){
+            dnsInfoHolder.dnsInfoText.text = dnsId
+            dnsInfoHolder.ping.text=""
+            dnsInfoHolder.dnsInfoText.setTextColor(Color.GRAY)
+        } else {
+            dnsInfoHolder.dnsInfoText.text = dnsId
+            dnsInfoHolder.ping.text = currentDNS.ping.toString() + " ms"
+            dnsInfoHolder.dnsInfoText.setTextColor(Color.WHITE)
+        }
+        dnsInfoHolder.checkbox.setOnCheckedChangeListener { _, isChecked ->
+            if(isChecked){
+                if(!this.currentDNS.contains(currentDNS)){
+                    this.currentDNS.add(currentDNS)
+                }
+            } else {
+                if(this.currentDNS.contains(currentDNS)){
+                    this.currentDNS.remove(currentDNS)
+                }
+            }
+        }
+        dnsInfoHolder.checkbox.isChecked = this.currentDNS.contains(currentDNS)
+        return listItem!!
+    }
+
+    fun getSelectedDNS(): Set<DNSInfo> {
+        return currentDNS
+    }
+
+    fun addItem(peerInfo: DNSInfo){
+        allDNS.add(peerInfo)
+    }
+
+    fun addAll(index: Int, peerInfo: ArrayList<DNSInfo>){
+        currentDNS.addAll(peerInfo)
+        allDNS.removeAll(peerInfo)
+        allDNS.addAll(index, peerInfo)
+        this.notifyDataSetChanged()
+    }
+
+    fun sort(){
+        allDNS = ArrayList(allDNS.sortedWith(compareBy { it.ping }))
+        this.notifyDataSetChanged()
+    }
+
+    class DNSInfoHolder {
+        lateinit var checkbox: CheckBox
+        lateinit var countryFlag: ImageView
+        lateinit var dnsInfoText: TextView
+        lateinit var ping: TextView
+    }
+}

app/src/main/java/io/github/chronosx88/yggdrasil/models/config/SelectPeerInfoListAdapter.kt

@@ -34,10 +34,10 @@ class SelectPeerInfoListAdapter(
         var peerInfoHolder = PeerInfoHolder()
         var listItem: View? = convertView
         if (listItem == null) {
-            listItem = LayoutInflater.from(mContext).inflate(R.layout.peers_list_item_edit, parent, false)
+            listItem = LayoutInflater.from(mContext).inflate(R.layout.host_list_item_edit, parent, false)
             peerInfoHolder.checkbox = listItem.findViewById(R.id.checkbox) as CheckBox
             peerInfoHolder.countryFlag = listItem.findViewById(R.id.countryFlag) as ImageView
-            peerInfoHolder.peerInfoText = listItem.findViewById(R.id.peerInfoText) as TextView
+            peerInfoHolder.peerInfoText = listItem.findViewById(R.id.hostInfoText) as TextView
             peerInfoHolder.ping = listItem.findViewById(R.id.ping) as TextView
             listItem.tag = peerInfoHolder
         } else {

app/src/main/java/io/github/chronosx88/yggdrasil/models/config/Utils.kt

@@ -0,0 +1,27 @@
+package io.github.chronosx88.yggdrasil.models.config
+
+import java.net.InetAddress
+import java.net.InetSocketAddress
+import java.net.Socket
+
+class Utils {
+
+    companion object {
+
+        @JvmStatic
+        fun ping(address: InetAddress, port:Int): Int {
+            val start = System.currentTimeMillis()
+            val socket = Socket()
+            try {
+                socket.connect(InetSocketAddress(address, port), 5000)
+                socket.close()
+            } catch (e: Exception) {
+                e.printStackTrace()
+                print(address)
+                return Int.MAX_VALUE
+            }
+            return (System.currentTimeMillis() - start).toInt()
+        }
+
+    }
+}

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

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout 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=".DNSListActivity"
+        android:background="@color/grey">
+
+    <com.google.android.material.appbar.AppBarLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:theme="@style/AppTheme.AppBarOverlay">
+
+        <androidx.appcompat.widget.Toolbar
+                android:id="@+id/toolbar"
+                android:layout_width="match_parent"
+                android:layout_height="?attr/actionBarSize"
+                android:background="?attr/colorPrimary"
+                app:popupTheme="@style/AppTheme.PopupOverlay" />
+
+    </com.google.android.material.appbar.AppBarLayout>
+
+    <include layout="@layout/content_dns_list" />
+
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+            android:id="@+id/fab"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="bottom|right"
+            android:layout_margin="@dimen/fab_margin"
+            app:backgroundTint="@color/green"
+            app:tint="@color/white"
+            app:borderWidth="0dp"
+            app:elevation="6dp"
+            app:fabSize="normal"
+            app:srcCompat="@android:drawable/ic_input_add"
+            android:visibility="gone"/>
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

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

@@ -131,7 +131,7 @@
 
         </androidx.constraintlayout.widget.ConstraintLayout>
         <ListView
-                android:id="@+id/dnsList"
+                android:id="@+id/dns"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent"
                 android:gravity="center_vertical"

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

@@ -0,0 +1,13 @@
+<?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:layout_width="match_parent"
+        android:layout_height="match_parent"
+        app:layout_behavior="@string/appbar_scrolling_view_behavior">
+    <ListView
+            android:id="@+id/dnsList"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:divider="@color/dark_20"
+            android:dividerHeight="2px"/>
+</androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -15,7 +15,7 @@
                 android:scaleType="fitStart"/>
     </FrameLayout>
     <TextView
-            android:id="@+id/peerInfoText"
+            android:id="@+id/hostInfoText"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:gravity="center_vertical"

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

@@ -31,7 +31,7 @@
             android:layout_toEndOf="@+id/frame"
             android:layout_centerInParent="true"/>
     <TextView
-            android:id="@+id/peerInfoText"
+            android:id="@+id/hostInfoText"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:gravity="center_vertical"

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

@@ -4,4 +4,5 @@
     <string name="disconnect_button">Disconnect</string>
     <string name="switch_button_title">SwitchOn</string>
     <string name="title_activity_peer_list">Edit peers</string>
+    <string name="title_activity_dns_list">Edit DNS</string>
 </resources>