Reworked packet decoding/encoding

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

@@ -3,13 +3,14 @@ package org.adde0109.ambassador.forge;
 import org.adde0109.ambassador.forge.packet.ModListPacket;
 import org.adde0109.ambassador.forge.packet.ModListReplyPacket;
 
+import java.util.List;
+
 public class ForgeHandshake {
 
     private ModListPacket modListPacket;
     private ModListReplyPacket modListReplyPacket;
 
     public ForgeHandshake() {
-
     }
 
     public ModListPacket getModListPacket() {

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

@@ -6,13 +6,11 @@ import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.network.Connections;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
-import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.packet.AvailableCommands;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.PluginMessage;
-import io.netty.buffer.ByteBuf;
 import org.adde0109.ambassador.forge.pipeline.CommandDecoderErrorCatcher;
-import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperDecoder;
+import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperCodec;
 
 public enum VelocityForgeBackendConnectionPhase implements BackendConnectionPhase {
   NOT_STARTED() {
@@ -82,10 +80,6 @@ public enum VelocityForgeBackendConnectionPhase implements BackendConnectionPhas
     //Forge server
     //To avoid unnecessary resets, we wait until we get the handshake even if we know that we should
     //reset because that the previous server was Forge.
-
-    ForgeLoginWrapperDecoder decoder = (ForgeLoginWrapperDecoder) player.getConnection()
-            .getChannel().pipeline().get(ForgeConstants.FORGE_HANDSHAKE_DECODER);
-    decoder.registerLoginWrapperID(message.getId());
   }
 
   public void onLoginSuccess(VelocityServerConnection serverCon, ConnectedPlayer player) {

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

@@ -14,12 +14,10 @@ import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.PluginMessage;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import net.kyori.adventure.text.Component;
 import org.adde0109.ambassador.Ambassador;
 import org.adde0109.ambassador.forge.packet.Context;
 import org.adde0109.ambassador.forge.packet.IForgeLoginWrapperPacket;
 import org.adde0109.ambassador.forge.packet.ModListReplyPacket;
-import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperDecoder;
 import org.adde0109.ambassador.velocity.client.FML2CRPMResetCompleteDecoder;
 import org.adde0109.ambassador.velocity.client.OutboundSuccessHolder;
 import org.adde0109.ambassador.velocity.client.ClientPacketQueue;
@@ -170,16 +168,6 @@ public enum VelocityForgeClientConnectionPhase implements ClientConnectionPhase
     return true;
   }
 
-  public void sendVanillaModlist(ConnectedPlayer player) {
-    player.getConnection().write(new LoginPluginMessage(0, "fml:loginwrapper",
-            Unpooled.wrappedBuffer(player.getConnection().getType() == ForgeConstants.ForgeFML3 ?
-                    ForgeHandshakeUtils.emptyModlistFML3 : ForgeHandshakeUtils.emptyModlistFML2)));
-
-    ForgeLoginWrapperDecoder decoder = (ForgeLoginWrapperDecoder) player.getConnection()
-            .getChannel().pipeline().get(ForgeConstants.FORGE_HANDSHAKE_DECODER);
-    decoder.registerLoginWrapperID(0);
-  }
-
   public void complete(ConnectedPlayer player) {
     complete(player, isResettable(player));
   }

src/main/java/org/adde0109/ambassador/forge/packet/ACKPacket.java

@@ -7,12 +7,8 @@ public class ACKPacket implements IForgeLoginWrapperPacket<Context.ClientContext
 
     private final Context.ClientContext context;
 
-    ACKPacket(int msgID, boolean success) {
+    public ACKPacket(Context.ClientContext context) {
-        this.context = Context.createContext(msgID, success);
+        this.context = context;
-    }
-
-    ACKPacket read(ByteBuf input, int msgID, boolean success) {
-        return new ACKPacket(msgID, success);
     }
     @Override
     public ByteBuf encode() {

src/main/java/org/adde0109/ambassador/forge/packet/ConfigDataPacket.java

@@ -2,12 +2,12 @@ package org.adde0109.ambassador.forge.packet;
 
 import io.netty.buffer.ByteBuf;
 
-public class configDataPacket implements IForgeLoginWrapperPacket<Context> {
+public class ConfigDataPacket implements IForgeLoginWrapperPacket<Context> {
 
     private final Context context;
 
-    public configDataPacket(int msgID) {
+    public ConfigDataPacket(Context context) {
-        this.context = Context.createContext(msgID);
+        this.context = context;
     }
 
     @Override

src/main/java/org/adde0109/ambassador/forge/packet/Context.java

@@ -8,11 +8,11 @@ public class Context {
     this.responseID = responseID;
   }
 
-  static Context createContext(int responseID) {
+  public static Context createContext(int responseID) {
     return new Context(responseID);
   }
 
-  static ClientContext createContext(int responseID, boolean clientSuccess) {
+  public static ClientContext createContext(int responseID, boolean clientSuccess) {
     return new ClientContext(responseID,clientSuccess);
   }
 

src/main/java/org/adde0109/ambassador/forge/packet/GenericForgeLoginWrapperPacket.java

@@ -13,12 +13,9 @@ public class GenericForgeLoginWrapperPacket<T extends Context> extends DeferredB
     this.context = context;
   }
 
-  static public GenericForgeLoginWrapperPacket<Context> create(ByteBuf input, int id) {
-    return new GenericForgeLoginWrapperPacket<>(input, Context.createContext(id));
-  }
 
-  static public GenericForgeLoginWrapperPacket<Context> create(ByteBuf input, int id, boolean success) {
+  static public GenericForgeLoginWrapperPacket<Context> create(ByteBuf input, Context context) {
-    return new GenericForgeLoginWrapperPacket<>(input, Context.createContext(id, success));
+    return new GenericForgeLoginWrapperPacket<>(input, context);
   }
 
   @Override

src/main/java/org/adde0109/ambassador/forge/packet/ModListPacket.java

@@ -19,15 +19,15 @@ public class ModListPacket implements IForgeLoginWrapperPacket<Context> {
 
     private final Context context;
     private ModListPacket(List<String> mods, Map<ChannelIdentifier,
-            String> channels, List<String> registries, int id, List<String> dataPackRegistries) {
+            String> channels, List<String> registries, Context context, List<String> dataPackRegistries) {
         this.mods = mods;
         this.channels = channels;
         this.registries = registries;
-        this.context = Context.createContext(id);
+        this.context = context;
         this.dataPackRegistries = dataPackRegistries;
     }
 
-    public static ModListPacket read(ByteBuf input, int msgID, boolean FML3) {
+    public static ModListPacket read(ByteBuf input, Context context) {
 
         List<String> mods = new ArrayList<>();
         int len = ProtocolUtils.readVarInt(input);
@@ -46,13 +46,13 @@ public class ModListPacket implements IForgeLoginWrapperPacket<Context> {
             registries.add(ProtocolUtils.readString(input, 32767));
 
         List<String> dataPackRegistries = new ArrayList<>();
-        if (FML3) {
+        if (input.isReadable()) {
             len = ProtocolUtils.readVarInt(input);
             for (int x = 0; x < len; x++)
                 dataPackRegistries.add(ProtocolUtils.readString(input, 0x100));
         }
 
-        return new ModListPacket(mods, channels, registries, msgID, dataPackRegistries);
+        return new ModListPacket(mods, channels, registries, context, dataPackRegistries);
     }
 
     @Override

src/main/java/org/adde0109/ambassador/forge/packet/ModListReplyPacket.java

@@ -20,14 +20,14 @@ public class ModListReplyPacket implements IForgeLoginWrapperPacket<Context.Clie
 
   private final Context.ClientContext context;
   private ModListReplyPacket(List<String> mods, Map<ChannelIdentifier,
-          String> channels, Map<String, String> registries, int id, boolean success) {
+          String> channels, Map<String, String> registries, Context.ClientContext context) {
     this.mods = mods;
     this.channels = channels;
     this.registries = registries;
-    this.context = Context.createContext(id, success);
+    this.context = context;
   }
 
-  public static ModListReplyPacket read(ByteBuf input, int msgID) {
+  public static ModListReplyPacket read(ByteBuf input, Context.ClientContext context) {
 
     List<String> mods = new ArrayList<>();
     int len = ProtocolUtils.readVarInt(input);
@@ -45,7 +45,7 @@ public class ModListReplyPacket implements IForgeLoginWrapperPacket<Context.Clie
     for (int x = 0; x < len; x++)
       registries.put(ProtocolUtils.readString(input, 32767), ProtocolUtils.readString(input, 0x100));
 
-    return new ModListReplyPacket(mods, channels, registries, msgID, true);
+    return new ModListReplyPacket(mods, channels, registries, context);
   }
 
   @Override

src/main/java/org/adde0109/ambassador/forge/packet/RegistryPacket.java

@@ -0,0 +1,21 @@
+package org.adde0109.ambassador.forge.packet;
+
+import io.netty.buffer.ByteBuf;
+
+public class RegistryPacket implements IForgeLoginWrapperPacket<Context> {
+
+  private final Context context;
+  public RegistryPacket(Context context) {
+    this.context = context;
+  }
+
+  @Override
+  public ByteBuf encode() {
+    return null;
+  }
+
+  @Override
+  public Context getContext() {
+    return context;
+  }
+}

src/main/java/org/adde0109/ambassador/forge/pipeline/ForgeLoginWrapperCodec.java

@@ -0,0 +1,82 @@
+package org.adde0109.ambassador.forge.pipeline;
+
+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.util.DeferredByteBufHolder;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.DecoderException;
+import io.netty.handler.codec.MessageToMessageCodec;
+import org.adde0109.ambassador.forge.packet.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ForgeLoginWrapperCodec extends MessageToMessageCodec<DeferredByteBufHolder, IForgeLoginWrapperPacket<?>> {
+
+  private final List<Integer> loginWrapperIDs = new ArrayList<>();
+
+  @Override
+  protected void decode(ChannelHandlerContext ctx, DeferredByteBufHolder in, List<Object> out) throws Exception {
+    ByteBuf buf = in.content();
+
+    Context context;
+    if (in instanceof LoginPluginMessage msg && msg.getChannel().equals("fml:loginwrapper")) {
+      context = Context.createContext(msg.getId());
+    } else if (in instanceof LoginPluginResponse msg && loginWrapperIDs.remove(msg.getId()) != null) {
+      context = Context.createContext(msg.getId(), msg.isSuccess());
+    } else {
+      return;
+    }
+
+    int originalReaderIndex = buf.readerIndex();
+    try {
+      String channel = ProtocolUtils.readString(buf);
+      if (!channel.equals("fml:handshake")) {
+        throw new DecoderException();
+      } else {
+        int length = ProtocolUtils.readVarInt(buf);
+        int packetID = ProtocolUtils.readVarInt(buf);
+        if (context instanceof Context.ClientContext clientContext) {
+          switch (packetID) {
+            case 2:
+              out.add(ModListReplyPacket.read(buf, clientContext));
+              break;
+            case 99:
+              out.add(new ACKPacket(clientContext));
+            default:
+              throw new DecoderException();
+          }
+        } else {
+          switch (packetID) {
+            case 1:
+              out.add(ModListPacket.read(buf, context));
+              break;
+            case 3:
+              out.add(new RegistryPacket(context));
+              break;
+            case 4:
+              out.add(new ConfigDataPacket(context));
+              break;
+            default:
+              throw new DecoderException();
+          }
+        }
+      }
+    } catch (DecoderException e) {
+      buf.readerIndex(originalReaderIndex);
+      out.add(GenericForgeLoginWrapperPacket.create(buf.retain(), context));
+    }
+  }
+
+  @Override
+  protected void encode(ChannelHandlerContext ctx, IForgeLoginWrapperPacket<?> msg, List<Object> out) throws Exception {
+    if (msg.getContext() instanceof Context.ClientContext clientContext) {
+      out.add(new LoginPluginResponse(clientContext.getResponseID(), clientContext.success(), msg.encode()));
+    } else {
+      out.add(new LoginPluginMessage(msg.getContext().getResponseID(), "fml:loginwrapper", msg.encode()));
+      this.loginWrapperIDs.add(msg.getContext().getResponseID());
+    }
+  }
+}

src/main/java/org/adde0109/ambassador/forge/pipeline/ForgeLoginWrapperDecoder.java

@@ -1,45 +0,0 @@
-package org.adde0109.ambassador.forge.pipeline;
-
-import com.velocitypowered.proxy.protocol.ProtocolUtils;
-import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.handler.codec.MessageToMessageDecoder;
-import org.adde0109.ambassador.forge.packet.GenericForgeLoginWrapperPacket;
-import org.adde0109.ambassador.forge.packet.ModListReplyPacket;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class ForgeLoginWrapperDecoder extends MessageToMessageDecoder<LoginPluginResponse> {
-
-  private final List<Integer> loginWrapperIDs = new ArrayList<>();
-
-  @Override
-  protected void decode(ChannelHandlerContext ctx, LoginPluginResponse msg, List<Object> out) throws Exception {
-    ByteBuf buf = msg.content();
-    if (!loginWrapperIDs.remove((Integer) msg.getId())) {
-      out.add(msg.retain());
-      return;
-    }
-    int originalReaderIndex = msg.content().readerIndex();
-    String channel = ProtocolUtils.readString(buf);
-    if (!channel.equals("fml:handshake")) {
-      buf.readerIndex(originalReaderIndex);
-      out.add(GenericForgeLoginWrapperPacket.create(buf.retain(), msg.getId(), true));
-      return;
-    }
-    int length = ProtocolUtils.readVarInt(buf);
-    int packetID = ProtocolUtils.readVarInt(buf);
-    if (packetID == 2) {
-      out.add(ModListReplyPacket.read(msg.content(), msg.getId()));
-    } else {
-      buf.readerIndex(originalReaderIndex);
-      out.add(GenericForgeLoginWrapperPacket.create(buf.retain(), msg.getId(), true));
-    }
-  }
-
-  public void registerLoginWrapperID(int loginWrapperID) {
-    this.loginWrapperIDs.add(loginWrapperID);
-  }
-}

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

@@ -3,7 +3,6 @@ package org.adde0109.ambassador.velocity;
 import com.velocitypowered.api.event.Continuation;
 import com.velocitypowered.api.event.PostOrder;
 import com.velocitypowered.api.event.Subscribe;
-import com.velocitypowered.api.event.connection.LoginEvent;
 import com.velocitypowered.api.event.connection.PostLoginEvent;
 import com.velocitypowered.api.event.player.*;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
@@ -12,12 +11,11 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.network.Connections;
 import com.velocitypowered.proxy.protocol.StateRegistry;
-import net.kyori.adventure.text.Component;
 import org.adde0109.ambassador.Ambassador;
 import org.adde0109.ambassador.forge.ForgeConstants;
 import org.adde0109.ambassador.forge.ForgeFMLConnectionType;
 import org.adde0109.ambassador.forge.VelocityForgeClientConnectionPhase;
-import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperDecoder;
+import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperCodec;
 import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperHandler;
 
 public class VelocityEventHandler {
@@ -39,7 +37,7 @@ public class VelocityEventHandler {
 
         player.getConnection().getChannel().pipeline().addBefore(
                 Connections.HANDLER,
-                ForgeConstants.FORGE_HANDSHAKE_DECODER, new ForgeLoginWrapperDecoder());
+                ForgeConstants.FORGE_HANDSHAKE_DECODER, new ForgeLoginWrapperCodec());
         player.getConnection().getChannel().pipeline().addAfter(
                 ForgeConstants.FORGE_HANDSHAKE_DECODER,
                 ForgeConstants.FORGE_HANDSHAKE_HANDLER, new ForgeLoginWrapperHandler(player));

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

@@ -51,7 +51,7 @@ public class ForgeLoginSessionHandler implements MinecraftSessionHandler {
     if (!(serverConnection.getConnection().getType() instanceof ForgeFMLConnectionType)) {
       if (player.getConnectedServer() == null ||
               player.getConnectedServer().getConnection().getType() instanceof ForgeFMLConnectionType) {
-        //Initial Vanilla
+        //Initial Vanilla - test if the client can be reset
         //Forge -> vanilla
         player.getPhase().resetConnectionPhase(player);
         player.getConnectionInFlight().getConnection().getChannel().config().setAutoRead(false);

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

@@ -4,10 +4,14 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.backend.LoginSessionHandler;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
+import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.network.Connections;
 import com.velocitypowered.proxy.protocol.StateRegistry;
 import io.netty.channel.*;
+import org.adde0109.ambassador.forge.ForgeConstants;
 import org.adde0109.ambassador.forge.ForgeFMLConnectionType;
+import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperCodec;
+import org.adde0109.ambassador.forge.pipeline.ForgeLoginWrapperHandler;
 import org.jetbrains.annotations.NotNull;
 
 public class VelocityForgeBackendHandshakeHandler extends ChannelInboundHandlerAdapter {
@@ -25,9 +29,17 @@ public class VelocityForgeBackendHandshakeHandler extends ChannelInboundHandlerA
 
     ctx.pipeline().remove(this);
 
-    if (serverConnection.getPlayer().getConnection().getType() instanceof ForgeFMLConnectionType) {
+    ConnectedPlayer player = serverConnection.getPlayer();
+    if (player.getConnection().getType() instanceof ForgeFMLConnectionType) {
       ForgeLoginSessionHandler forgeLoginSessionHandler = new ForgeLoginSessionHandler((LoginSessionHandler) connection.getActiveSessionHandler(), serverConnection,server);
       connection.setActiveSessionHandler(StateRegistry.LOGIN, forgeLoginSessionHandler);
+
+      player.getConnection().getChannel().pipeline().addBefore(
+              Connections.HANDLER,
+              ForgeConstants.FORGE_HANDSHAKE_DECODER, new ForgeLoginWrapperCodec());
+      player.getConnection().getChannel().pipeline().addAfter(
+              ForgeConstants.FORGE_HANDSHAKE_DECODER,
+              ForgeConstants.FORGE_HANDSHAKE_HANDLER, new ForgeLoginWrapperHandler(player));
     }
 
     ctx.pipeline().fireChannelActive();

src/main/java/org/adde0109/ambassador/velocity/client/FML2CRPMResetCompleteDecoder.java

@@ -5,6 +5,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
+import org.adde0109.ambassador.forge.packet.Context;
 import org.adde0109.ambassador.forge.packet.GenericForgeLoginWrapperPacket;
 import org.adde0109.ambassador.forge.packet.IForgeLoginWrapperPacket;
 
@@ -26,8 +27,8 @@ public class FML2CRPMResetCompleteDecoder extends ChannelInboundHandlerAdapter {
           boolean success = buf.readBoolean();
           if (id == 98) {
             try {
-              IForgeLoginWrapperPacket packet = GenericForgeLoginWrapperPacket.create(Unpooled.EMPTY_BUFFER, id, success);
+              ctx.fireChannelRead(GenericForgeLoginWrapperPacket.create(
-              ctx.fireChannelRead(packet);
+                      Unpooled.EMPTY_BUFFER, Context.createContext(id, success)));
             } finally {
               buf.release();
             }