it works minus SRV

core/src/mindustry/net/ArcNetProvider.java

@@ -212,14 +212,16 @@ public class ArcNetProvider implements NetProvider{
     @Override
     public void pingHost(String address, int port, Cons<Host> valid, Cons<Exception> invalid){
         long time = Time.millis();
-        var socket = new InetSocketAddress(address, port);
-        Log.info("Time to resolve @: @", address, Time.timeSinceMillis(time));
 
-        AsyncUdp.send(socket, 2000, 512, ByteBuffer.wrap(new byte[]{-2, 1}), data ->  {
-            Host host = NetworkIO.readServerData((int)Time.timeSinceMillis(time), socket.getAddress().getHostAddress(), data);
-            host.port = port;
-            Core.app.post(() -> valid.get(host));
-        }, e -> Core.app.post(() -> invalid.get(e)));
+        Dns.resolveAddress(address, inetaddr -> {
+            var socket = new InetSocketAddress(inetaddr, port);
+
+            AsyncUdp.send(socket, 2000, 512, ByteBuffer.wrap(new byte[]{-2, 1}), data ->  {
+                Host host = NetworkIO.readServerData((int)Time.timeSinceMillis(time), socket.getAddress().getHostAddress(), data);
+                host.port = port;
+                Core.app.post(() -> valid.get(host));
+            }, e -> Core.app.post(() -> invalid.get(e)));
+        }, err -> Core.app.post(() -> invalid.get(err)));
 
         /*
         try{

core/src/mindustry/net/AsyncUdp.java

@@ -54,15 +54,14 @@ public class AsyncUdp{
 
                                     request.received.get(buffer);
                                     request.close();
-                                }catch(IOException error){
+                                }catch(Exception error){
                                     request.fail(error);
-                                    //TODO remove logging, this is not needed outside of debugging
-                                    Log.err(error);
                                 }
                             }
 
                         }
-                    }catch(IOException e){
+                    }catch(Throwable e){
+                        //should not happen
                         Log.err(e);
                     }
                 }
@@ -98,7 +97,6 @@ public class AsyncUdp{
 
                 removals.offer(req);
             }catch(Exception e){
-                Log.err(e);
                 failed.get(e);
             }
         });
@@ -115,6 +113,8 @@ public class AsyncUdp{
         final DatagramChannel channel;
         final SelectionKey key;
 
+        boolean closed = false;
+
         public Request(InetSocketAddress address, long timeout, int bufferSize, ByteBuffer data, DatagramChannel channel, SelectionKey key, Cons<ByteBuffer> received, Cons<Exception> failed){
             this.address = address;
             this.timeout = timeout;
@@ -128,8 +128,8 @@ public class AsyncUdp{
         }
 
         void close(){
-            if(!key.isValid()) return;
             try{
+                closed = true;
                 key.cancel();
                 channel.close();
             }catch(Exception close){
@@ -138,9 +138,10 @@ public class AsyncUdp{
         }
 
         void fail(Exception error){
-            if(!key.isValid()) return;
-            failed.get(error);
-            close();
+            if(!closed){
+                failed.get(error);
+                close();
+            }
         }
 
         @Override

core/src/mindustry/net/Dns.java

@@ -0,0 +1,146 @@
+package mindustry.net;
+
+import arc.func.*;
+import arc.math.*;
+import arc.struct.*;
+import arc.util.*;
+
+import java.net.*;
+import java.nio.*;
+import java.nio.channels.*;
+import java.nio.charset.*;
+import java.util.regex.*;
+
+public class Dns{
+    private static final Pattern ipPattern = Pattern.compile("^((0|1\\d?\\d?|2[0-4]?\\d?|25[0-5]?|[3-9]\\d?)\\.){3}(0|1\\d?\\d?|2[0-4]?\\d?|25[0-5]?|[3-9]\\d?)$");
+    private static final int aRecord = 1, srvRecord = 33;
+    private static IntMap<ObjectMap<String, Seq<?>>> cache = new IntMap<>();
+    private static Seq<InetSocketAddress> nameservers = Seq.with(new InetSocketAddress("1.1.1.1", 53), new InetSocketAddress("8.8.8.8", 53));
+
+    static <T> void resolve(int type, String domain, Func<ByteBuffer, T> reader, Cons<Seq<T>> result, Cons<Exception> error){
+        ObjectMap<String, Seq<?>> map;
+
+        synchronized(cache){
+            map = cache.get(type, ObjectMap::new);
+
+            //TODO timeout
+            if(map.containsKey(domain)){
+                result.get((Seq<T>)map.get(domain));
+                return;
+            }
+        }
+
+        send(Seq.with(new InetSocketAddress("1.1.1.1", 53)), 0, type, domain, reader, records -> {
+            synchronized(cache){
+                //cache the records
+                map.put(domain, records);
+            }
+
+            result.get(records);
+        }, error);
+    }
+
+    static void resolveAddress(String domain, Cons<InetAddress> result, Cons<Exception> error){
+        if(ipPattern.matcher(domain).matches()){
+            try{
+                result.get(InetAddress.getByName(domain));
+            }catch(Exception e){
+                error.get(e);
+                return;
+            }
+        }
+
+        resolve(aRecord, domain, bytes -> {
+            byte[] address = new byte[4];
+            bytes.get(address);
+            return address;
+        }, addresses -> {
+            try{
+                if(addresses.size > 0){
+                    result.get(InetAddress.getByAddress(addresses.get(0)));
+                }else{
+                    //there are no records found
+                    error.get(new UnresolvedAddressException());
+                }
+            }catch(UnknownHostException unknown){
+                error.get(unknown);
+            }
+        }, error);
+    }
+
+    static <T> void send(Seq<InetSocketAddress> addresses, int index, int type, String domain, Func<ByteBuffer, T> reader, Cons<Seq<T>> recordResult, Cons<Exception> error){
+        short id = (short)new Rand().nextInt(Short.MAX_VALUE);
+
+        ByteBuffer buffer = ByteBuffer.allocate(512);
+
+        buffer.putShort(id);             // Id
+        buffer.putShort((short) 0x0100); // Flags (recursion enabled)
+        buffer.putShort((short) 1);      // Questions
+        buffer.putShort((short) 0);      // Answers
+        buffer.putShort((short) 0);      // Authority
+        buffer.putShort((short) 0);      // Additional
+
+        // Domain
+        for(String part : domain.split("\\.")) {
+            buffer.put((byte) part.length());
+            buffer.put(part.getBytes(StandardCharsets.UTF_8));
+        }
+        buffer.put((byte) 0);
+
+        buffer.putShort((short) type);   // Type
+        buffer.putShort((short) 1);      // Class (Internet)
+
+        buffer.flip();
+
+        AsyncUdp.send(addresses.get(index), 2000, 512, buffer, result -> {
+            short responseId = result.getShort();
+            if(responseId != id) {
+                throw new ArcRuntimeException("Invalid response ID");
+            }
+
+            result.getShort();
+            result.getShort();
+            int answers = result.getShort() & 0xFFFF;
+            result.getShort();
+            result.getShort();
+
+            byte len;
+            while((len = result.get()) != 0) {
+                result.position(result.position() + len);
+            }
+
+            result.getShort();
+            result.getShort();
+
+            var records = new Seq<T>(answers);
+
+            for(int i = 0; i < answers; i++) {
+                result.getShort();                           // OFFSET
+                int answerType = result.getShort() & 0xFFFF; // Type
+                result.getShort();                           // Class
+                long ttl = result.getInt() & 0xFFFFFFFFL;    // TTL
+                int length = result.getShort() & 0xFFFF;     // Data length
+
+                // Optionally CNAME results will be returned with the A results, skip those
+                if(answerType != type){
+                    result.position(result.position() + length);
+                    continue;
+                }
+
+                int position = result.position();
+
+                records.add(reader.get(result));
+
+                result.position(position + length);
+            }
+
+            recordResult.get(records);
+        }, e -> {
+            if(index >= addresses.size - 1){
+                error.get(e);
+            }else{
+                send(addresses, index + 1, type, domain, reader, recordResult, error);
+            }
+        });
+    }
+}