WIP: More backend work

src/main/java/org/adde0109/ambassador/forge/ForgeFML2ClientConnectionPhase.java

@@ -7,6 +7,7 @@ import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
 import org.adde0109.ambassador.velocity.VelocityForgeClientConnectionPhase;
 import org.adde0109.ambassador.velocity.VelocityForgeHandshakeSessionHandler;
@@ -17,7 +18,9 @@ import java.util.Optional;
 
 public class ForgeFML2ClientConnectionPhase implements VelocityForgeClientConnectionPhase {
   private boolean isResettable;
-  private Optional<ByteBuf> modListData = Optional.empty();
+
+  //TODO: Use modData inside ConnectedPlayer instead
+  public byte[] modListData;
 
   private final ArrayList<Integer> listenerList = new ArrayList();
   private Continuation whenComplete;
@@ -54,7 +57,7 @@ public class ForgeFML2ClientConnectionPhase implements VelocityForgeClientConnec
         player.getConnection().close();
         return true;
       }
-      modListData = Optional.of(packet.content().retain());
+      modListData = ByteBufUtil.getBytes(packet.content());
     }
     if (listenerList.isEmpty()) {
       whenComplete.resume();

src/main/java/org/adde0109/ambassador/forge/ForgeHandshakeUtils.java

@@ -74,6 +74,19 @@ public class ForgeHandshakeUtils {
     return stream.toByteArray();
   }
 
+  public static final byte[] ACKPacket = generateACKPacket();
+  private static byte[] generateACKPacket() {
+    ByteArrayDataOutput dataAndPacketIdStream = ByteStreams.newDataOutput();
+    writeVarInt(dataAndPacketIdStream,4);
+
+    ByteArrayDataOutput stream = ByteStreams.newDataOutput();
+    byte[] dataAndPacketId = dataAndPacketIdStream.toByteArray();
+    writeUtf(stream,"fml:handshake");
+    writeVarInt(stream,dataAndPacketId.length);
+    stream.write(dataAndPacketId);
+    return stream.toByteArray();
+  }
+
   public static class HandshakeReceiver {
 
     private int partLength;

src/main/java/org/adde0109/ambassador/velocity/VelocityEventHandler.java

@@ -6,9 +6,12 @@ import com.velocitypowered.api.event.permission.PermissionsSetupEvent;
 import com.velocitypowered.api.event.player.ServerLoginPluginMessageEvent;
 import com.velocitypowered.proxy.connection.ConnectionTypes;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.backend.BackendConnectionPhases;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
+import io.netty.buffer.Unpooled;
 import org.adde0109.ambassador.Ambassador;
 import org.adde0109.ambassador.forge.ForgeFML2ClientConnectionPhase;
 import org.adde0109.ambassador.forge.ForgeFML2ConnectionType;
@@ -40,17 +43,22 @@ public class VelocityEventHandler {
 
   @Subscribe
   public void onServerLoginPluginMessageEvent(ServerLoginPluginMessageEvent event, Continuation continuation) {
-    if (!Objects.equals(event.getIdentifier().getId(), "fml:loginwrapper")) {
+    if (!Objects.equals(event.getIdentifier().getId(), "fml:loginwrapper") || !(((ConnectedPlayer)event.getConnection().getPlayer()).getPhase() instanceof VelocityForgeClientConnectionPhase)) {
       continuation.resume();
       return;
     }
     final VelocityServerConnection serverCon = (VelocityServerConnection) event.getConnection();
     final MinecraftConnection connection = serverCon.getConnection();
-    serverCon.setConnectionPhase(new VelocityForgeBackendConnectionPhase());
+    if (connection == null) {
-    if (connection != null) {
+      //This should never happen.
-      connection.setType(new ForgeFML2ConnectionType());
+      continuation.resumeWithException(new NullPointerException());
-      connection.setSessionHandler(new VelocityForgeBackendHandshakeSessionHandler(connection.getSessionHandler(),serverCon,serverCon.getPlayer()));
+      return;
     }
+    serverCon.setConnectionPhase(new VelocityForgeBackendConnectionPhase());
+    connection.setType(new ForgeFML2ConnectionType());
+    MinecraftSessionHandler sessionHandler = new VelocityForgeBackendHandshakeSessionHandler(connection.getSessionHandler(),serverCon);
+    connection.setSessionHandler(sessionHandler);
+    sessionHandler.handle(new LoginPluginMessage(event.getSequenceId(),event.getIdentifier().getId(), Unpooled.wrappedBuffer(event.getContents())));
     continuation.resume();
   }
 }

src/main/java/org/adde0109/ambassador/velocity/backend/VelocityForgeBackendConnectionPhase.java

@@ -1,14 +1,51 @@
 package org.adde0109.ambassador.velocity.backend;
 
+import com.google.common.io.ByteArrayDataInput;
+import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.backend.BackendConnectionPhase;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
+import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import com.velocitypowered.proxy.protocol.packet.PluginMessage;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.adde0109.ambassador.forge.ForgeFML2ClientConnectionPhase;
+import org.adde0109.ambassador.forge.ForgeHandshakeUtils;
+import org.adde0109.ambassador.velocity.VelocityForgeClientConnectionPhase;
+
+import java.io.EOFException;
 
 public class VelocityForgeBackendConnectionPhase implements BackendConnectionPhase {
 
   public boolean handle(VelocityServerConnection server, ConnectedPlayer player, LoginPluginMessage message) {
+    if (!message.getChannel().equals("fml:loginwrapper") || !(player.getPhase() instanceof VelocityForgeClientConnectionPhase)) {
+      return false;
+    }
+    MinecraftConnection connection = server.getConnection();
+    if (connection == null) {
+      throw new NullPointerException();
+    }
+
+    ByteBuf content = message.content();
+    content.readBytes(14);  //Channel Identifier
+    ProtocolUtils.readVarInt(content); //Length
+    int packetID = ProtocolUtils.readVarInt(content);
+
+
+    switch (packetID) {
+
+      case 1:
+        final byte[] data = ((ForgeFML2ClientConnectionPhase) player.getPhase()).modListData;
+        connection.write(new LoginPluginResponse(message.getId(),true, Unpooled.wrappedBuffer(data)));
+        break;
+
+      default:
+        connection.write(new LoginPluginResponse(message.getId(),true,Unpooled.wrappedBuffer(ForgeHandshakeUtils.ACKPacket)));
+        break;
+    }
+
     return true;
   }
 }

src/main/java/org/adde0109/ambassador/velocity/backend/VelocityForgeBackendHandshakeSessionHandler.java

@@ -37,7 +37,6 @@ public class VelocityForgeBackendHandshakeSessionHandler implements MinecraftSes
 
   @Override
   public boolean handle(ServerLoginSuccess packet) {
-
     return original.handle(packet);
   }
 }