Fix support for 1.20.2+ clients to older servers on bungeecord

bungee/src/main/java/com/viaversion/viaversion/bungee/handlers/BungeeEncodeHandler.java

@@ -24,6 +24,7 @@
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPipeline;
 import io.netty.handler.codec.MessageToMessageEncoder;
 import java.util.List;
 
@@ -36,6 +37,10 @@ public BungeeEncodeHandler(UserConnection info) {
  this.info = info;
  }
 
+ public UserConnection getInfo() {
+ return info;
+ }
+
  @Override
  protected void encode(final ChannelHandlerContext ctx, ByteBuf bytebuf, List<Object> out) throws Exception {
  if (!ctx.channel().isActive()) {
@@ -65,7 +70,8 @@ protected void encode(final ChannelHandlerContext ctx, ByteBuf bytebuf, List<Obj
 
  private boolean handleCompressionOrder(ChannelHandlerContext ctx, ByteBuf buf) {
  boolean needsCompress = false;
- if (!handledCompression && ctx.pipeline().names().indexOf("compress") > ctx.pipeline().names().indexOf("via-encoder")) {
+ ChannelPipeline pipeline = ctx.pipeline();
+ if (!handledCompression && shouldFixCompressionOrder(pipeline)) {
  // Need to decompress this packet due to bad order
  ByteBuf decompressed = BungeePipelineUtil.decompress(ctx, buf);
 
@@ -79,18 +85,26 @@ private boolean handleCompressionOrder(ChannelHandlerContext ctx, ByteBuf buf) {
  }
 
  // Reorder the pipeline
- ChannelHandler decoder = ctx.pipeline().get("via-decoder");
- ChannelHandler encoder = ctx.pipeline().get("via-encoder");
- ctx.pipeline().remove(decoder);
- ctx.pipeline().remove(encoder);
- ctx.pipeline().addAfter("decompress", "via-decoder", decoder);
- ctx.pipeline().addAfter("compress", "via-encoder", encoder);
+ fixCompressionPipeline(pipeline);
  needsCompress = true;
  handledCompression = true;
  }
  return needsCompress;
  }
 
+ public static boolean shouldFixCompressionOrder(ChannelPipeline pipeline) {
+ return pipeline.names().indexOf("compress") > pipeline.names().indexOf("via-encoder");
+ }
+
+ public static void fixCompressionPipeline(ChannelPipeline pipeline) {
+ ChannelHandler decoder = pipeline.get("via-decoder");
+ ChannelHandler encoder = pipeline.get("via-encoder");
+ pipeline.remove(decoder);
+ pipeline.remove(encoder);
+ pipeline.addAfter("decompress", "via-decoder", decoder);
+ pipeline.addAfter("compress", "via-encoder", encoder);
+ }
+
  private void recompress(ChannelHandlerContext ctx, ByteBuf buf) {
  ByteBuf compressed = BungeePipelineUtil.compress(ctx, buf);
  try {

bungee/src/main/java/com/viaversion/viaversion/bungee/handlers/BungeeServerHandler.java

@@ -27,14 +27,19 @@
 import com.viaversion.viaversion.api.protocol.ProtocolPathEntry;
 import com.viaversion.viaversion.api.protocol.ProtocolPipeline;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.protocol.packet.State;
 import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.bungee.storage.BungeeStorage;
+import com.viaversion.viaversion.protocols.base.ClientboundLoginPackets;
 import com.viaversion.viaversion.protocols.protocol1_13to1_12_2.packets.InventoryPackets;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.Protocol1_20_2To1_20;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.ClientboundPackets1_9;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.Protocol1_9To1_8;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.providers.EntityIdProvider;
 import com.viaversion.viaversion.protocols.protocol1_9to1_8.storage.EntityTracker1_9;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelPipeline;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -46,6 +51,7 @@
 import java.util.UUID;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
 import net.md_5.bungee.api.connection.Server;
+import net.md_5.bungee.api.event.PostLoginEvent;
 import net.md_5.bungee.api.event.ServerConnectEvent;
 import net.md_5.bungee.api.event.ServerConnectedEvent;
 import net.md_5.bungee.api.event.ServerSwitchEvent;
@@ -65,6 +71,11 @@ public class BungeeServerHandler implements Listener {
  private static final Field entityRewrite;
  private static final Field channelWrapper;
 
+ private static final Field channelWrapperChannel;
+ private static final Object GAME;
+ private static final Method setEncodeProtocol;
+ private static final Method setDecodeProtocol;
+
  static {
  try {
  getHandshake = Class.forName("net.md_5.bungee.connection.InitialHandler").getDeclaredMethod("getHandshake");
@@ -73,16 +84,63 @@ public class BungeeServerHandler implements Listener {
  setProtocol = Class.forName("net.md_5.bungee.protocol.packet.Handshake").getDeclaredMethod("setProtocolVersion", int.class);
  getEntityMap = Class.forName("net.md_5.bungee.entitymap.EntityMap").getDeclaredMethod("getEntityMap", int.class);
  setVersion = Class.forName("net.md_5.bungee.netty.ChannelWrapper").getDeclaredMethod("setVersion", int.class);
+
+ Class<?> clazzProtocol = Class.forName("net.md_5.bungee.protocol.Protocol");
+ setEncodeProtocol = Class.forName("net.md_5.bungee.netty.ChannelWrapper").getDeclaredMethod("setEncodeProtocol", clazzProtocol);
+ setDecodeProtocol = Class.forName("net.md_5.bungee.netty.ChannelWrapper").getDeclaredMethod("setDecodeProtocol", clazzProtocol);
+ GAME = clazzProtocol.getField("GAME").get(null);
  channelWrapper = Class.forName("net.md_5.bungee.UserConnection").getDeclaredField("ch");
  channelWrapper.setAccessible(true);
  entityRewrite = Class.forName("net.md_5.bungee.UserConnection").getDeclaredField("entityRewrite");
  entityRewrite.setAccessible(true);
+
+ channelWrapperChannel = Class
+ .forName("net.md_5.bungee.netty.ChannelWrapper")
+ .getDeclaredField("ch");
+ channelWrapperChannel.setAccessible(true);
  } catch (ReflectiveOperationException e) {
  Via.getPlatform().getLogger().severe("Error initializing BungeeServerHandler, try updating BungeeCord or ViaVersion!");
  throw new RuntimeException(e);
  }
  }
 
+ @EventHandler
+ public void onPostLogin(PostLoginEvent event) {
+ // On 1.20.2, bungeecord does not eagerly send out
+ // ClientboundLoginPackets.GAME_PROFILE before connecting to the game
+ // server. However, this leads to skipping over the pipeline handling
+ // that typically initializes connections, which in turn leads to
+ // ConnectionManager::getConnectedClient returning null in the code
+ // below.
+ //
+ // To work around this, we emulate the successful login here for 1.20.2+
+ // clients.
+ int clientVer = event.getPlayer().getPendingConnection().getVersion();
+ if (clientVer < ProtocolVersion.v1_20_2.getVersion()) {
+ return;
+ }
+
+ Channel c;
+ try {
+ Object ch = channelWrapper.get(event.getPlayer());
+ c = (Channel) channelWrapperChannel.get(ch);
+ } catch (IllegalArgumentException | IllegalAccessException e) {
+ e.printStackTrace();
+ return;
+ }
+
+ BungeeEncodeHandler encoder = (BungeeEncodeHandler) c.pipeline()
+ .get("via-encoder");
+
+ UserConnection userConnection = encoder.getInfo();
+ userConnection.getProtocolInfo().setUuid(
+ event.getPlayer().getUniqueId());
+ userConnection.getProtocolInfo().setUsername(
+ event.getPlayer().getName());
+
+ Via.getManager().getConnectionManager().onLoginSuccess(userConnection);
+ }
+
  // Set the handshake version every time someone connects to any server
  @EventHandler(priority = 120)
  public void onServerConnect(ServerConnectEvent event) {
@@ -109,6 +167,32 @@ public void onServerConnect(ServerConnectEvent event) {
  setProtocol.invoke(handshake, protocols == null ? clientProtocolVersion : serverProtocolVersion);
  } catch (InvocationTargetException | IllegalAccessException e) {
  e.printStackTrace();
+ return;
+ }
+
+ try {
+ Object ch = channelWrapper.get(event.getPlayer());
+ Channel c = (Channel) channelWrapperChannel.get(ch);
+
+ // Eagerly fix up compression order to avoid surprises when sending
+ // packets.
+ ChannelPipeline pipeline = c.pipeline();
+ if (BungeeEncodeHandler.shouldFixCompressionOrder(pipeline)) {
+ BungeeEncodeHandler.fixCompressionPipeline(pipeline);
+ }
+
+ if (serverProtocolVersion < ProtocolVersion.v1_20_2.getVersion()
+ && ProtocolVersion.v1_20_2.getVersion() <= clientProtocolVersion
+ && event.getPlayer().getServer() == null
+ && user.getProtocolInfo().getClientState() == State.LOGIN) {
+ // Bungeecord does not set itself to the right mode if it was
+ // initially in 1.20.2+ mode
+ setEncodeProtocol.invoke(ch, GAME);
+ setDecodeProtocol.invoke(ch, GAME);
+ }
+ } catch (ReflectiveOperationException e) {
+ e.printStackTrace();
+ return;
  }
  }
 
@@ -283,10 +367,29 @@ public void checkServerChange(ServerConnectedEvent event, UserConnection user) t
  }
  }
 
- Object wrapper = channelWrapper.get(player);
- setVersion.invoke(wrapper, serverProtocolVersion);
+ {
+ Object wrapper = channelWrapper.get(player);
+ setVersion.invoke(wrapper, serverProtocolVersion);
+ }
 
  Object entityMap = getEntityMap.invoke(null, serverProtocolVersion);
  entityRewrite.set(player, entityMap);
+
+ // Complete the login process if bungeecord has skipped it
+ if (serverProtocolVersion < ProtocolVersion.v1_20_2.getVersion()
+ && event.getPlayer().getServer() == null
+ && user.getProtocolInfo().getClientState() == State.LOGIN) {
+ PacketWrapper wrapper = PacketWrapper.create(
+ ClientboundLoginPackets.GAME_PROFILE,
+ user);
+ wrapper.write(Type.UUID, event.getPlayer().getUniqueId());
+ wrapper.write(Type.STRING, event.getPlayer().getName());
+ wrapper.write(Type.VAR_INT, 0); // TODO: Properties
+ try {
+ wrapper.send(Protocol1_20_2To1_20.class, false);
+ } catch (Exception e) {
+ e.printStackTrace();
+ }
+ }
  }
 }

common/src/main/java/com/viaversion/viaversion/protocols/base/BaseProtocol1_7.java

@@ -121,6 +121,10 @@ public void register() {
  ProtocolInfo info = wrapper.user().getProtocolInfo();
  if (info.getProtocolVersion() < ProtocolVersion.v1_20_2.getVersion()) { // On 1.20.2+, wait for the login ack
  info.setState(State.PLAY);
+ } else {
+ // FIXME: Hack to not break on the UUID type when we send it
+ // manually.
+ return;
  }
 
  UUID uuid = passthroughLoginUUID(wrapper);