1.20.2 Support (#1088)

Co-authored-by: RednedEpic <redned235@gmail.com>
Co-authored-by: Gero <gecam59@gmail.com>

.gitignore

@@ -83,6 +83,8 @@ gradle-app.setting
 logs/
 /velocity.toml
 /forwarding.secret
+forwarding.secret
+velocity.toml
 server-icon.png
 /bin/
 run/

api/src/main/java/com/velocitypowered/api/network/ProtocolVersion.java

@@ -62,7 +62,8 @@ public enum ProtocolVersion {
   MINECRAFT_1_19_1(760, "1.19.1", "1.19.2"),
   MINECRAFT_1_19_3(761, "1.19.3"),
   MINECRAFT_1_19_4(762, "1.19.4"),
-  MINECRAFT_1_20(763, "1.20", "1.20.1");
+  MINECRAFT_1_20(763, "1.20", "1.20.1"),
+  MINECRAFT_1_20_2(764, "1.20.2");
 
   private static final int SNAPSHOT_BIT = 30;
 

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -36,6 +36,7 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.client.HandshakeSessionHandler;
 import com.velocitypowered.proxy.connection.client.InitialLoginSessionHandler;
 import com.velocitypowered.proxy.connection.client.StatusSessionHandler;
+import com.velocitypowered.proxy.network.Connections;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.VelocityConnectionEvent;
@@ -46,6 +47,7 @@ import com.velocitypowered.proxy.protocol.netty.MinecraftCompressorAndLengthEnco
 import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftEncoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftVarintLengthEncoder;
+import com.velocitypowered.proxy.protocol.netty.PlayPacketQueueHandler;
 import com.velocitypowered.proxy.util.except.QuietDecoderException;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
@@ -60,6 +62,9 @@ import io.netty.util.ReferenceCountUtil;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import java.security.GeneralSecurityException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.SecretKeySpec;
@@ -78,7 +83,8 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   private final Channel channel;
   private SocketAddress remoteAddress;
   private StateRegistry state;
-  private @Nullable MinecraftSessionHandler sessionHandler;
+  private Map<StateRegistry, MinecraftSessionHandler> sessionHandlers;
+  private @Nullable MinecraftSessionHandler activeSessionHandler;
   private ProtocolVersion protocolVersion;
   private @Nullable MinecraftConnectionAssociation association;
   public final VelocityServer server;
@@ -96,12 +102,14 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     this.remoteAddress = channel.remoteAddress();
     this.server = server;
     this.state = StateRegistry.HANDSHAKE;
+
+    this.sessionHandlers = new HashMap<>();
   }
 
   @Override
   public void channelActive(ChannelHandlerContext ctx) throws Exception {
-    if (sessionHandler != null) {
+    if (activeSessionHandler != null) {
-      sessionHandler.connected();
+      activeSessionHandler.connected();
     }
 
     if (association != null && server.getConfiguration().isLogPlayerConnections()) {
@@ -111,12 +119,12 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
 
   @Override
   public void channelInactive(ChannelHandlerContext ctx) throws Exception {
-    if (sessionHandler != null) {
+    if (activeSessionHandler != null) {
-      sessionHandler.disconnected();
+      activeSessionHandler.disconnected();
     }
 
     if (association != null && !knownDisconnect
-        && !(sessionHandler instanceof StatusSessionHandler)
+        && !(activeSessionHandler instanceof StatusSessionHandler)
         && server.getConfiguration().isLogPlayerConnections()) {
       logger.info("{} has disconnected", association);
     }
@@ -125,12 +133,12 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   @Override
   public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
     try {
-      if (sessionHandler == null) {
+      if (activeSessionHandler == null) {
         // No session handler available, do nothing
         return;
       }
 
-      if (sessionHandler.beforeHandle()) {
+      if (activeSessionHandler.beforeHandle()) {
         return;
       }
 
@@ -140,15 +148,15 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
 
       if (msg instanceof MinecraftPacket) {
         MinecraftPacket pkt = (MinecraftPacket) msg;
-        if (!pkt.handle(sessionHandler)) {
+        if (!pkt.handle(activeSessionHandler)) {
-          sessionHandler.handleGeneric((MinecraftPacket) msg);
+          activeSessionHandler.handleGeneric((MinecraftPacket) msg);
         }
       } else if (msg instanceof HAProxyMessage) {
         HAProxyMessage proxyMessage = (HAProxyMessage) msg;
         this.remoteAddress = new InetSocketAddress(proxyMessage.sourceAddress(),
             proxyMessage.sourcePort());
       } else if (msg instanceof ByteBuf) {
-        sessionHandler.handleUnknown((ByteBuf) msg);
+        activeSessionHandler.handleUnknown((ByteBuf) msg);
       }
     } finally {
       ReferenceCountUtil.release(msg);
@@ -157,20 +165,21 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
 
   @Override
   public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
-    if (sessionHandler != null) {
+    if (activeSessionHandler != null) {
-      sessionHandler.readCompleted();
+      activeSessionHandler.readCompleted();
     }
   }
 
   @Override
   public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
     if (ctx.channel().isActive()) {
-      if (sessionHandler != null) {
+      if (activeSessionHandler != null) {
         try {
-          sessionHandler.exception(cause);
+          activeSessionHandler.exception(cause);
         } catch (Exception ex) {
           logger.error("{}: exception handling exception in {}",
-              (association != null ? association : channel.remoteAddress()), sessionHandler, cause);
+              (association != null ? association : channel.remoteAddress()), activeSessionHandler,
+              cause);
         }
       }
 
@@ -178,13 +187,14 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
         if (cause instanceof ReadTimeoutException) {
           logger.error("{}: read timed out", association);
         } else {
-          boolean frontlineHandler = sessionHandler instanceof InitialLoginSessionHandler
+          boolean frontlineHandler = activeSessionHandler instanceof InitialLoginSessionHandler
-              || sessionHandler instanceof HandshakeSessionHandler
+              || activeSessionHandler instanceof HandshakeSessionHandler
-              || sessionHandler instanceof StatusSessionHandler;
+              || activeSessionHandler instanceof StatusSessionHandler;
           boolean isQuietDecoderException = cause instanceof QuietDecoderException;
           boolean willLog = !isQuietDecoderException && !frontlineHandler;
           if (willLog) {
-            logger.error("{}: exception encountered in {}", association, sessionHandler, cause);
+            logger.error("{}: exception encountered in {}", association, activeSessionHandler,
+                cause);
           } else {
             knownDisconnect = true;
           }
@@ -197,8 +207,8 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
 
   @Override
   public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
-    if (sessionHandler != null) {
+    if (activeSessionHandler != null) {
-      sessionHandler.writabilityChanged();
+      activeSessionHandler.writabilityChanged();
     }
   }
 
@@ -323,7 +333,7 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   }
 
   /**
-   * Determines whether or not the channel should continue reading data automaticaly.
+   * Determines whether or not the channel should continue reading data automatically.
    *
    * @param autoReading whether or not we should read data automatically
    */
@@ -341,10 +351,12 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     }
   }
 
+  // Ideally only used by the state switch
+
   /**
-   * Changes the state of the Minecraft connection.
+   * Sets the new state for the connection.
    *
-   * @param state the new state
+   * @param state the state to use
    */
   public void setState(StateRegistry state) {
     ensureInEventLoop();
@@ -352,6 +364,25 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     this.state = state;
     this.channel.pipeline().get(MinecraftEncoder.class).setState(state);
     this.channel.pipeline().get(MinecraftDecoder.class).setState(state);
+
+    if (state == StateRegistry.CONFIG) {
+      // Activate the play packet queue
+      addPlayPacketQueueHandler();
+    } else if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE) != null) {
+      // Remove the queue
+      this.channel.pipeline().remove(Connections.PLAY_PACKET_QUEUE);
+    }
+  }
+
+  /**
+   * Adds the play packet queue handler.
+   */
+  public void addPlayPacketQueueHandler() {
+    if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE) == null) {
+      this.channel.pipeline().addAfter(Connections.MINECRAFT_ENCODER, Connections.PLAY_PACKET_QUEUE,
+           new PlayPacketQueueHandler(this.protocolVersion,
+                channel.pipeline().get(MinecraftEncoder.class).getDirection()));
+    }
   }
 
   public ProtocolVersion getProtocolVersion() {
@@ -382,32 +413,81 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     }
   }
 
-  public @Nullable MinecraftSessionHandler getSessionHandler() {
+  public @Nullable MinecraftSessionHandler getActiveSessionHandler() {
-    return sessionHandler;
+    return activeSessionHandler;
+  }
+
+  public @Nullable MinecraftSessionHandler getSessionHandlerForRegistry(StateRegistry registry) {
+    return this.sessionHandlers.getOrDefault(registry, null);
   }
 
   /**
    * Sets the session handler for this connection.
    *
+   * @param registry       the registry of the handler
    * @param sessionHandler the handler to use
    */
-  public void setSessionHandler(MinecraftSessionHandler sessionHandler) {
+  public void setActiveSessionHandler(StateRegistry registry,
+                                      MinecraftSessionHandler sessionHandler) {
+    Preconditions.checkNotNull(registry);
     ensureInEventLoop();
 
-    if (this.sessionHandler != null) {
+    if (this.activeSessionHandler != null) {
-      this.sessionHandler.deactivated();
+      this.activeSessionHandler.deactivated();
     }
-    this.sessionHandler = sessionHandler;
+    this.sessionHandlers.put(registry, sessionHandler);
+    this.activeSessionHandler = sessionHandler;
+    setState(registry);
     sessionHandler.activated();
   }
 
+  /**
+   * Switches the active session handler to the respective registry one.
+   *
+   * @param registry the registry of the handler
+   * @return true if successful and handler is present
+   */
+  public boolean setActiveSessionHandler(StateRegistry registry) {
+    Preconditions.checkNotNull(registry);
+    ensureInEventLoop();
+
+    MinecraftSessionHandler handler = getSessionHandlerForRegistry(registry);
+    if (handler != null) {
+      boolean flag = true;
+      if (this.activeSessionHandler != null
+          && (flag = !Objects.equals(handler, this.activeSessionHandler))) {
+        this.activeSessionHandler.deactivated();
+      }
+      this.activeSessionHandler = handler;
+      setState(registry);
+      if (flag) {
+        handler.activated();
+      }
+    }
+    return handler != null;
+  }
+
+  /**
+   * Adds a secondary session handler for this connection.
+   *
+   * @param registry       the registry of the handler
+   * @param sessionHandler the handler to use
+   */
+  public void addSessionHandler(StateRegistry registry, MinecraftSessionHandler sessionHandler) {
+    Preconditions.checkNotNull(registry);
+    Preconditions.checkArgument(registry != state, "Handler would overwrite handler");
+    ensureInEventLoop();
+
+    this.sessionHandlers.put(registry, sessionHandler);
+  }
+
   private void ensureOpen() {
     Preconditions.checkState(!isClosed(), "Connection is closed.");
   }
 
   /**
-   * Sets the compression threshold on the connection. You are responsible for sending
+   * Sets the compression threshold on the connection. You are responsible for sending {@link
-   * {@link com.velocitypowered.proxy.protocol.packet.SetCompression} beforehand.
+   * com.velocitypowered.proxy.protocol.packet.SetCompression} beforehand.
    *
    * @param threshold the compression threshold to use
    */
@@ -497,5 +577,4 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   public void setType(ConnectionType connectionType) {
     this.connectionType = connectionType;
   }
-
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftSessionHandler.java

@@ -31,8 +31,10 @@ import com.velocitypowered.proxy.protocol.packet.KeepAlive;
 import com.velocitypowered.proxy.protocol.packet.LegacyHandshake;
 import com.velocitypowered.proxy.protocol.packet.LegacyPing;
 import com.velocitypowered.proxy.protocol.packet.LegacyPlayerListItem;
+import com.velocitypowered.proxy.protocol.packet.LoginAcknowledged;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
+import com.velocitypowered.proxy.protocol.packet.PingIdentify;
 import com.velocitypowered.proxy.protocol.packet.PluginMessage;
 import com.velocitypowered.proxy.protocol.packet.RemovePlayerInfo;
 import com.velocitypowered.proxy.protocol.packet.ResourcePackRequest;
@@ -55,6 +57,11 @@ import com.velocitypowered.proxy.protocol.packet.chat.keyed.KeyedPlayerCommand;
 import com.velocitypowered.proxy.protocol.packet.chat.legacy.LegacyChat;
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionPlayerChat;
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionPlayerCommand;
+import com.velocitypowered.proxy.protocol.packet.config.ActiveFeatures;
+import com.velocitypowered.proxy.protocol.packet.config.FinishedUpdate;
+import com.velocitypowered.proxy.protocol.packet.config.RegistrySync;
+import com.velocitypowered.proxy.protocol.packet.config.StartUpdate;
+import com.velocitypowered.proxy.protocol.packet.config.TagsUpdate;
 import com.velocitypowered.proxy.protocol.packet.title.LegacyTitlePacket;
 import com.velocitypowered.proxy.protocol.packet.title.TitleActionbarPacket;
 import com.velocitypowered.proxy.protocol.packet.title.TitleClearPacket;
@@ -279,4 +286,32 @@ public interface MinecraftSessionHandler {
   default boolean handle(UpsertPlayerInfo packet) {
     return false;
   }
+
+  default boolean handle(LoginAcknowledged packet) {
+    return false;
+  }
+
+  default boolean handle(ActiveFeatures packet) {
+    return false;
+  }
+
+  default boolean handle(FinishedUpdate packet) {
+    return false;
+  }
+
+  default boolean handle(RegistrySync packet) {
+    return false;
+  }
+
+  default boolean handle(TagsUpdate packet) {
+    return false;
+  }
+
+  default boolean handle(StartUpdate packet) {
+    return false;
+  }
+
+  default boolean handle(PingIdentify pingIdentify) {
+    return false;
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -39,8 +39,11 @@ import com.velocitypowered.proxy.connection.client.ClientPlaySessionHandler;
 import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.StateRegistry;
+import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.packet.AvailableCommands;
 import com.velocitypowered.proxy.protocol.packet.BossBar;
+import com.velocitypowered.proxy.protocol.packet.ClientSettings;
 import com.velocitypowered.proxy.protocol.packet.Disconnect;
 import com.velocitypowered.proxy.protocol.packet.KeepAlive;
 import com.velocitypowered.proxy.protocol.packet.LegacyPlayerListItem;
@@ -51,6 +54,7 @@ import com.velocitypowered.proxy.protocol.packet.ResourcePackResponse;
 import com.velocitypowered.proxy.protocol.packet.ServerData;
 import com.velocitypowered.proxy.protocol.packet.TabCompleteResponse;
 import com.velocitypowered.proxy.protocol.packet.UpsertPlayerInfo;
+import com.velocitypowered.proxy.protocol.packet.config.StartUpdate;
 import com.velocitypowered.proxy.protocol.util.PluginMessageUtil;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
@@ -68,10 +72,10 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
   private static final Pattern PLAUSIBLE_SHA1_HASH = Pattern.compile("^[a-z0-9]{40}$");
   private static final Logger logger = LogManager.getLogger(BackendPlaySessionHandler.class);
-  private static final boolean BACKPRESSURE_LOG = Boolean
+  private static final boolean BACKPRESSURE_LOG =
-      .getBoolean("velocity.log-server-backpressure");
+      Boolean.getBoolean("velocity.log-server-backpressure");
-  private static final int MAXIMUM_PACKETS_TO_FLUSH = Integer
+  private static final int MAXIMUM_PACKETS_TO_FLUSH =
-      .getInteger("velocity.max-packets-per-flush", 8192);
+      Integer.getInteger("velocity.max-packets-per-flush", 8192);
 
   private final VelocityServer server;
   private final VelocityServerConnection serverConn;
@@ -86,7 +90,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
     this.serverConn = serverConn;
     this.playerConnection = serverConn.getPlayer().getConnection();
 
-    MinecraftSessionHandler psh = playerConnection.getSessionHandler();
+    MinecraftSessionHandler psh = playerConnection.getActiveSessionHandler();
     if (!(psh instanceof ClientPlaySessionHandler)) {
       throw new IllegalStateException(
           "Initializing BackendPlaySessionHandler with no backing client play session handler!");
@@ -119,12 +123,28 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
     return false;
   }
 
+  @Override
+  public boolean handle(StartUpdate packet) {
+    MinecraftConnection smc = serverConn.ensureConnected();
+    smc.setAutoReading(false);
+    // Even when not auto reading messages are still decoded. Decode them with the correct state
+    smc.getChannel().pipeline().get(MinecraftDecoder.class).setState(StateRegistry.CONFIG);
+    serverConn.getPlayer().switchToConfigState();
+    return true;
+  }
+
   @Override
   public boolean handle(KeepAlive packet) {
     serverConn.getPendingPings().put(packet.getRandomId(), System.currentTimeMillis());
     return false; // forwards on
   }
 
+  @Override
+  public boolean handle(ClientSettings packet) {
+    serverConn.ensureConnected().write(packet);
+    return true;
+  }
+
   @Override
   public boolean handle(Disconnect packet) {
     serverConn.disconnect();
@@ -221,17 +241,13 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
     }
 
     byte[] copy = ByteBufUtil.getBytes(packet.content());
-    PluginMessageEvent event = new PluginMessageEvent(serverConn, serverConn.getPlayer(), id,
+    PluginMessageEvent event = new PluginMessageEvent(serverConn, serverConn.getPlayer(), id, copy);
-        copy);
+    server.getEventManager().fire(event).thenAcceptAsync(pme -> {
-    server.getEventManager().fire(event)
-        .thenAcceptAsync(pme -> {
       if (pme.getResult().isAllowed() && !playerConnection.isClosed()) {
-            PluginMessage copied = new PluginMessage(packet.getChannel(),
+        PluginMessage copied = new PluginMessage(packet.getChannel(), Unpooled.wrappedBuffer(copy));
-                Unpooled.wrappedBuffer(copy));
         playerConnection.write(copied);
       }
-        }, playerConnection.eventLoop())
+    }, playerConnection.eventLoop()).exceptionally((ex) -> {
-        .exceptionally((ex) -> {
       logger.error("Exception while handling plugin message {}", packet, ex);
       return null;
     });
@@ -283,18 +299,13 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(ServerData packet) {
-    server.getServerListPingHandler().getInitialPing(this.serverConn.getPlayer())
+    server.getServerListPingHandler().getInitialPing(this.serverConn.getPlayer()).thenComposeAsync(
-        .thenComposeAsync(
         ping -> server.getEventManager()
             .fire(new ProxyPingEvent(this.serverConn.getPlayer(), ping)),
-            playerConnection.eventLoop()
+        playerConnection.eventLoop()).thenAcceptAsync(pingEvent -> this.playerConnection.write(
-        )
-        .thenAcceptAsync(pingEvent ->
-            this.playerConnection.write(
             new ServerData(pingEvent.getPing().getDescriptionComponent(),
-                    pingEvent.getPing().getFavicon().orElse(null),
+                pingEvent.getPing().getFavicon().orElse(null), packet.isSecureChatEnforced())),
-                    packet.isSecureChatEnforced())
+        playerConnection.eventLoop());
-            ), playerConnection.eventLoop());
     return true;
   }
 

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/ConfigSessionHandler.java

@@ -0,0 +1,229 @@
+/*
+ * Copyright (C) 2019-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.connection.backend;
+
+import com.velocitypowered.api.event.player.PlayerResourcePackStatusEvent;
+import com.velocitypowered.api.event.player.ServerResourcePackSendEvent;
+import com.velocitypowered.api.proxy.player.ResourcePackInfo;
+import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.proxy.connection.MinecraftConnection;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.connection.client.ClientConfigSessionHandler;
+import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.util.ConnectionMessages;
+import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
+import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.StateRegistry;
+import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
+import com.velocitypowered.proxy.protocol.packet.Disconnect;
+import com.velocitypowered.proxy.protocol.packet.KeepAlive;
+import com.velocitypowered.proxy.protocol.packet.PluginMessage;
+import com.velocitypowered.proxy.protocol.packet.ResourcePackRequest;
+import com.velocitypowered.proxy.protocol.packet.ResourcePackResponse;
+import com.velocitypowered.proxy.protocol.packet.config.FinishedUpdate;
+import com.velocitypowered.proxy.protocol.packet.config.RegistrySync;
+import com.velocitypowered.proxy.protocol.packet.config.StartUpdate;
+import com.velocitypowered.proxy.protocol.packet.config.TagsUpdate;
+import com.velocitypowered.proxy.protocol.util.PluginMessageUtil;
+import java.io.IOException;
+import java.util.concurrent.CompletableFuture;
+import java.util.regex.Pattern;
+import net.kyori.adventure.text.Component;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+/**
+ * A special session handler that catches "last minute" disconnects. This version is to accommodate
+ * 1.20.2+ switching. Yes, some of this is exceptionally stupid.
+ */
+public class ConfigSessionHandler implements MinecraftSessionHandler {
+
+  private static final Pattern PLAUSIBLE_SHA1_HASH = Pattern.compile("^[a-z0-9]{40}$");
+  private static final Logger logger = LogManager.getLogger(ConfigSessionHandler.class);
+  private final VelocityServer server;
+  private final VelocityServerConnection serverConn;
+  private final CompletableFuture<Impl> resultFuture;
+
+  private ResourcePackInfo resourcePackToApply;
+
+  private State state;
+
+  /**
+   * Creates the new transition handler.
+   *
+   * @param server       the Velocity server instance
+   * @param serverConn   the server connection
+   * @param resultFuture the result future
+   */
+  ConfigSessionHandler(VelocityServer server, VelocityServerConnection serverConn,
+                       CompletableFuture<Impl> resultFuture) {
+    this.server = server;
+    this.serverConn = serverConn;
+    this.resultFuture = resultFuture;
+    this.state = State.START;
+  }
+
+  @Override
+  public void activated() {
+    resourcePackToApply = serverConn.getPlayer().getAppliedResourcePack();
+    serverConn.getPlayer().clearAppliedResourcePack();
+  }
+
+  @Override
+  public boolean beforeHandle() {
+    if (!serverConn.isActive()) {
+      // Obsolete connection
+      serverConn.disconnect();
+      return true;
+    }
+    return false;
+  }
+
+  @Override
+  public boolean handle(StartUpdate packet) {
+    serverConn.ensureConnected().write(packet);
+    return true;
+  }
+
+  @Override
+  public boolean handle(TagsUpdate packet) {
+    serverConn.getPlayer().getConnection().write(packet);
+    return true;
+  }
+
+  @Override
+  public boolean handle(KeepAlive packet) {
+    serverConn.ensureConnected().write(packet);
+    return true;
+  }
+
+  @Override
+  public boolean handle(ResourcePackRequest packet) {
+    final MinecraftConnection playerConnection = serverConn.getPlayer().getConnection();
+
+    ServerResourcePackSendEvent event =
+        new ServerResourcePackSendEvent(packet.toServerPromptedPack(), this.serverConn);
+
+    server.getEventManager().fire(event).thenAcceptAsync(serverResourcePackSendEvent -> {
+      if (playerConnection.isClosed()) {
+        return;
+      }
+      if (serverResourcePackSendEvent.getResult().isAllowed()) {
+        ResourcePackInfo toSend = serverResourcePackSendEvent.getProvidedResourcePack();
+        if (toSend != serverResourcePackSendEvent.getReceivedResourcePack()) {
+          ((VelocityResourcePackInfo) toSend).setOriginalOrigin(
+              ResourcePackInfo.Origin.DOWNSTREAM_SERVER);
+        }
+
+        resourcePackToApply = null;
+        serverConn.getPlayer().queueResourcePack(toSend);
+      } else if (serverConn.getConnection() != null) {
+        serverConn.getConnection().write(new ResourcePackResponse(packet.getHash(),
+            PlayerResourcePackStatusEvent.Status.DECLINED));
+      }
+    }, playerConnection.eventLoop()).exceptionally((ex) -> {
+      if (serverConn.getConnection() != null) {
+        serverConn.getConnection().write(new ResourcePackResponse(packet.getHash(),
+            PlayerResourcePackStatusEvent.Status.DECLINED));
+      }
+      logger.error("Exception while handling resource pack send for {}", playerConnection, ex);
+      return null;
+    });
+
+    return true;
+  }
+
+  @Override
+  public boolean handle(FinishedUpdate packet) {
+    MinecraftConnection smc = serverConn.ensureConnected();
+    ClientConfigSessionHandler configHandler =
+        (ClientConfigSessionHandler) serverConn.getPlayer().getConnection()
+            .getActiveSessionHandler();
+
+    smc.setAutoReading(false);
+    // Even when not auto reading messages are still decoded. Decode them with the correct state
+    smc.getChannel().pipeline().get(MinecraftDecoder.class).setState(StateRegistry.PLAY);
+    configHandler.handleBackendFinishUpdate(serverConn).thenAcceptAsync((unused) -> {
+      if (serverConn == serverConn.getPlayer().getConnectedServer()) {
+        smc.setActiveSessionHandler(StateRegistry.PLAY);
+      } else {
+        smc.setActiveSessionHandler(StateRegistry.PLAY,
+            new TransitionSessionHandler(server, serverConn, resultFuture));
+      }
+      if (serverConn.getPlayer().getAppliedResourcePack() == null && resourcePackToApply != null) {
+        serverConn.getPlayer().queueResourcePack(resourcePackToApply);
+      }
+      smc.setAutoReading(true);
+    }, smc.eventLoop());
+    return true;
+  }
+
+  @Override
+  public boolean handle(Disconnect packet) {
+    serverConn.disconnect();
+    resultFuture.complete(ConnectionRequestResults.forDisconnect(packet, serverConn.getServer()));
+    return true;
+  }
+
+  @Override
+  public boolean handle(PluginMessage packet) {
+    if (PluginMessageUtil.isMcBrand(packet)) {
+      serverConn.getPlayer().getConnection().write(
+          PluginMessageUtil.rewriteMinecraftBrand(packet, server.getVersion(),
+              serverConn.getPlayer().getProtocolVersion()));
+    } else {
+      // TODO: Change this so its usable for mod loaders
+      serverConn.disconnect();
+      resultFuture.complete(ConnectionRequestResults.forDisconnect(
+          Component.translatable("multiplayer.disconnect.missing_tags"), serverConn.getServer()));
+    }
+    return true;
+  }
+
+  @Override
+  public boolean handle(RegistrySync packet) {
+    serverConn.getPlayer().getConnection().write(packet.retain());
+    return true;
+  }
+
+  @Override
+  public void disconnected() {
+    resultFuture.completeExceptionally(
+        new IOException("Unexpectedly disconnected from remote server"));
+  }
+
+  @Override
+  public void handleGeneric(MinecraftPacket packet) {
+    serverConn.getPlayer().getConnection().write(packet);
+  }
+
+  private void switchFailure(Throwable cause) {
+    logger.error("Unable to switch to new server {} for {}", serverConn.getServerInfo().getName(),
+        serverConn.getPlayer().getUsername(), cause);
+    serverConn.getPlayer().disconnect(ConnectionMessages.INTERNAL_SERVER_CONNECTION_ERROR);
+    resultFuture.completeExceptionally(cause);
+  }
+
+  /**
+   * Represents the state of the configuration stage.
+   */
+  public static enum State {
+    START, NEGOTIATING, PLUGIN_MESSAGE_INTERRUPT, RESOURCE_PACK_INTERRUPT, COMPLETE
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/LoginSessionHandler.java

@@ -27,6 +27,7 @@ import com.velocitypowered.proxy.config.VelocityConfiguration;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.VelocityConstants;
+import com.velocitypowered.proxy.connection.client.ClientPlaySessionHandler;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
@@ -34,6 +35,7 @@ import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.packet.Disconnect;
 import com.velocitypowered.proxy.protocol.packet.EncryptionRequest;
+import com.velocitypowered.proxy.protocol.packet.LoginAcknowledged;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import com.velocitypowered.proxy.protocol.packet.ServerLoginSuccess;
@@ -59,8 +61,8 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
 
   private static final Logger logger = LogManager.getLogger(LoginSessionHandler.class);
 
-  private static final Component MODERN_IP_FORWARDING_FAILURE = Component
+  private static final Component MODERN_IP_FORWARDING_FAILURE =
-      .translatable("velocity.error.modern-forwarding-failed");
+      Component.translatable("velocity.error.modern-forwarding-failed");
 
   private final VelocityServer server;
   private final VelocityServerConnection serverConn;
@@ -150,10 +152,28 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
 
     // Move into the PLAY phase.
     MinecraftConnection smc = serverConn.ensureConnected();
-    smc.setState(StateRegistry.PLAY);
+    if (smc.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_20_2) < 0) {
+      smc.setActiveSessionHandler(StateRegistry.PLAY,
+          new TransitionSessionHandler(server, serverConn, resultFuture));
+    } else {
+      smc.setAutoReading(false);
+      CompletableFuture<Void> switchFuture;
+      if (serverConn.getPlayer().getConnection()
+          .getActiveSessionHandler() instanceof ClientPlaySessionHandler) {
+        switchFuture = ((ClientPlaySessionHandler) serverConn.getPlayer().getConnection()
+            .getActiveSessionHandler()).doSwitch();
+      } else {
+        switchFuture = CompletableFuture.completedFuture(null);
+      }
+      switchFuture.thenAcceptAsync((unused) -> {
+        smc.write(new LoginAcknowledged());
+        // Sync backend
+        smc.setActiveSessionHandler(StateRegistry.CONFIG,
+            new ConfigSessionHandler(server, serverConn, resultFuture));
+        smc.setAutoReading(true);
+      }, smc.eventLoop());
+    }
 
-    // Switch to the transition handler.
-    smc.setSessionHandler(new TransitionSessionHandler(server, serverConn, resultFuture));
     return true;
   }
 
@@ -165,12 +185,12 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
   @Override
   public void disconnected() {
     if (server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.LEGACY) {
-      resultFuture.completeExceptionally(
+      resultFuture.completeExceptionally(new QuietRuntimeException(
-          new QuietRuntimeException("The connection to the remote server was unexpectedly closed.\n"
+          "The connection to the remote server was unexpectedly closed.\n"
-              + "This is usually because the remote server does not have BungeeCord IP forwarding "
+              + "This is usually because the remote server "
+              + "does not have BungeeCord IP forwarding "
               + "correctly enabled.\nSee https://velocitypowered.com/wiki/users/forwarding/ "
-              + "for instructions on how to configure player info forwarding correctly.")
+              + "for instructions on how to configure player info forwarding correctly."));
-      );
     } else {
       resultFuture.completeExceptionally(
           new QuietRuntimeException("The connection to the remote server was unexpectedly closed.")

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/TransitionSessionHandler.java

@@ -32,6 +32,7 @@ import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
+import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.packet.Disconnect;
 import com.velocitypowered.proxy.protocol.packet.JoinGame;
 import com.velocitypowered.proxy.protocol.packet.KeepAlive;
@@ -120,17 +121,21 @@ public class TransitionSessionHandler implements MinecraftSessionHandler {
 
           // Change the client to use the ClientPlaySessionHandler if required.
           ClientPlaySessionHandler playHandler;
-          if (player.getConnection().getSessionHandler() instanceof ClientPlaySessionHandler) {
+          if (player.getConnection()
-            playHandler = (ClientPlaySessionHandler) player.getConnection().getSessionHandler();
+              .getActiveSessionHandler() instanceof ClientPlaySessionHandler) {
+            playHandler =
+                (ClientPlaySessionHandler) player.getConnection().getActiveSessionHandler();
           } else {
             playHandler = new ClientPlaySessionHandler(server, player);
-            player.getConnection().setSessionHandler(playHandler);
+            player.getConnection().setActiveSessionHandler(StateRegistry.PLAY, playHandler);
           }
+          assert playHandler != null;
           playHandler.handleBackendJoinGame(packet, serverConn);
 
           // Set the new play session handler for the server. We will have nothing more to do
           // with this connection once this task finishes up.
-          smc.setSessionHandler(new BackendPlaySessionHandler(server, serverConn));
+          smc.setActiveSessionHandler(StateRegistry.PLAY,
+              new BackendPlaySessionHandler(server, serverConn));
 
           // Clean up disabling auto-read while the connected event was being processed.
           smc.setAutoReading(true);
@@ -138,12 +143,15 @@ public class TransitionSessionHandler implements MinecraftSessionHandler {
           // Now set the connected server.
           serverConn.getPlayer().setConnectedServer(serverConn);
 
+          if (player.getClientSettingsPacket() != null) {
+            serverConn.ensureConnected().write(player.getClientSettingsPacket());
+          }
+
           // We're done! :)
           server.getEventManager().fireAndForget(new ServerPostConnectEvent(player,
               previousServer));
           resultFuture.complete(ConnectionRequestResults.successful(serverConn.getServer()));
-        }, smc.eventLoop())
+        }, smc.eventLoop()).exceptionally(exc -> {
-        .exceptionally(exc -> {
           logger.error("Unable to switch to new server {} for {}",
               serverConn.getServerInfo().getName(),
               player.getUsername(), exc);

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -34,6 +34,7 @@ import com.velocitypowered.proxy.config.PlayerInfoForwarding;
 import com.velocitypowered.proxy.connection.ConnectionTypes;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftConnectionAssociation;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
 import com.velocitypowered.proxy.protocol.StateRegistry;
@@ -91,8 +92,8 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
   /**
    * Connects to the server.
    *
-   * @return a {@link com.velocitypowered.api.proxy.ConnectionRequestBuilder.Result} representing
+   * @return a {@link com.velocitypowered.api.proxy.ConnectionRequestBuilder.Result}
-   *         whether or not the connect succeeded
+   *     representing whether the connection succeeded
    */
   public CompletableFuture<Impl> connect() {
     CompletableFuture<Impl> result = new CompletableFuture<>();
@@ -108,15 +109,21 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
             future.channel().pipeline().addLast(HANDLER, connection);
 
             // Kick off the connection process
-            connection.setSessionHandler(
+            if (!connection.setActiveSessionHandler(StateRegistry.HANDSHAKE)) {
-                new LoginSessionHandler(server, VelocityServerConnection.this, result));
+              MinecraftSessionHandler handler =
+                  new LoginSessionHandler(server, VelocityServerConnection.this, result);
+              connection.setActiveSessionHandler(StateRegistry.HANDSHAKE, handler);
+              connection.addSessionHandler(StateRegistry.LOGIN, handler);
+            }
 
-            // Set the connection phase, which may, for future forge (or whatever), be determined
+            // Set the connection phase, which may, for future forge (or whatever), be
+            // determined
             // at this point already
             connectionPhase = connection.getType().getInitialBackendPhase();
             startHandshake();
           } else {
-            // Complete the result immediately. ConnectedPlayer will reset the in-flight connection.
+            // Complete the result immediately. ConnectedPlayer will reset the in-flight
+            // connection.
             result.completeExceptionally(future.cause());
           }
         });
@@ -137,10 +144,8 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     // BungeeCord IP forwarding is simply a special injection after the "address" in the handshake,
     // separated by \0 (the null byte). In order, you send the original host, the player's IP, their
     // UUID (undashed), and if you are in online-mode, their login properties (from Mojang).
-    StringBuilder data = new StringBuilder()
+    StringBuilder data = new StringBuilder().append(proxyPlayer.getVirtualHost().orElseGet(() ->
-        .append(proxyPlayer.getVirtualHost()
+                    registeredServer.getServerInfo().getAddress()).getHostString())
-            .orElseGet(() -> registeredServer.getServerInfo().getAddress())
-            .getHostString())
         .append('\0')
         .append(getPlayerRemoteAddressAsString())
         .append('\0')
@@ -157,12 +162,10 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
 
   private String createBungeeGuardForwardingAddress(byte[] forwardingSecret) {
     // Append forwarding secret as a BungeeGuard token.
-    Property property = new Property("bungeeguard-token",
+    Property property =
-        new String(forwardingSecret, StandardCharsets.UTF_8), "");
+        new Property("bungeeguard-token", new String(forwardingSecret, StandardCharsets.UTF_8), "");
-    return createLegacyForwardingAddress(properties -> ImmutableList.<Property>builder()
+    return createLegacyForwardingAddress(
-        .addAll(properties)
+        properties -> ImmutableList.<Property>builder().addAll(properties).add(property).build());
-        .add(property)
-        .build());
   }
 
   private void startHandshake() {
@@ -171,8 +174,8 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
 
     // Initiate the handshake.
     ProtocolVersion protocolVersion = proxyPlayer.getConnection().getProtocolVersion();
-    String playerVhost = proxyPlayer.getVirtualHost()
+    String playerVhost =
-        .orElseGet(() -> registeredServer.getServerInfo().getAddress())
+        proxyPlayer.getVirtualHost().orElseGet(() -> registeredServer.getServerInfo().getAddress())
             .getHostString();
 
     Handshake handshake = new Handshake();
@@ -193,7 +196,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
     mc.delayedWrite(handshake);
 
     mc.setProtocolVersion(protocolVersion);
-    mc.setState(StateRegistry.LOGIN);
+    mc.setActiveSessionHandler(StateRegistry.LOGIN);
     if (proxyPlayer.getIdentifiedKey() == null
         && proxyPlayer.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_19_3) >= 0) {
       mc.delayedWrite(new ServerLogin(proxyPlayer.getUsername(), proxyPlayer.getUniqueId()));

proxy/src/main/java/com/velocitypowered/proxy/connection/client/AuthSessionHandler.java

@@ -26,6 +26,7 @@ import com.velocitypowered.api.event.connection.PostLoginEvent;
 import com.velocitypowered.api.event.permission.PermissionsSetupEvent;
 import com.velocitypowered.api.event.player.GameProfileRequestEvent;
 import com.velocitypowered.api.event.player.PlayerChooseInitialServerEvent;
+import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.permission.PermissionFunction;
 import com.velocitypowered.api.proxy.crypto.IdentifiedKey;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
@@ -38,6 +39,7 @@ import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.crypto.IdentifiedKeyImpl;
 import com.velocitypowered.proxy.protocol.StateRegistry;
+import com.velocitypowered.proxy.protocol.packet.LoginAcknowledged;
 import com.velocitypowered.proxy.protocol.packet.ServerLoginSuccess;
 import com.velocitypowered.proxy.protocol.packet.SetCompression;
 import io.netty.buffer.ByteBuf;
@@ -64,6 +66,7 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
   private GameProfile profile;
   private @MonotonicNonNull ConnectedPlayer connectedPlayer;
   private final boolean onlineMode;
+  private State loginState = State.START; // 1.20.2+
 
   AuthSessionHandler(VelocityServer server, LoginInboundConnection inbound,
       GameProfile profile, boolean onlineMode) {
@@ -95,8 +98,9 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
           inbound.getIdentifiedKey());
       this.connectedPlayer = player;
       if (!server.canRegisterConnection(player)) {
-        player.disconnect0(Component.translatable("velocity.error.already-connected-proxy",
+        player.disconnect0(
-            NamedTextColor.RED), true);
+            Component.translatable("velocity.error.already-connected-proxy", NamedTextColor.RED),
+            true);
         return CompletableFuture.completedFuture(null);
       }
 
@@ -109,16 +113,14 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
               // wait for permissions to load, then set the players permission function
               final PermissionFunction function = event.createFunction(player);
               if (function == null) {
-                logger.error(
+                logger.error("A plugin permission provider {} provided an invalid permission "
-                    "A plugin permission provider {} provided an invalid permission function"
+                        + "function for player {}. This is a bug in the plugin, not in "
-                        + " for player {}. This is a bug in the plugin, not in Velocity. Falling"
+                        + "Velocity. Falling back to the default permission function.",
-                        + " back to the default permission function.",
+                    event.getProvider().getClass().getName(), player.getUsername());
-                    event.getProvider().getClass().getName(),
-                    player.getUsername());
               } else {
                 player.setPermissionFunction(function);
               }
-              completeLoginProtocolPhaseAndInitialize(player);
+              startLoginCompletion(player);
             }
           }, mcConnection.eventLoop());
     }, mcConnection.eventLoop()).exceptionally((ex) -> {
@@ -127,7 +129,7 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
     });
   }
 
-  private void completeLoginProtocolPhaseAndInitialize(ConnectedPlayer player) {
+  private void startLoginCompletion(ConnectedPlayer player) {
     int threshold = server.getConfiguration().getCompressionThreshold();
     if (threshold >= 0 && mcConnection.getProtocolVersion().compareTo(MINECRAFT_1_8) >= 0) {
       mcConnection.write(new SetCompression(threshold));
@@ -165,17 +167,31 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
       }
     }
 
-    ServerLoginSuccess success = new ServerLoginSuccess();
+    completeLoginProtocolPhaseAndInitialize(player);
-    success.setUsername(player.getUsername());
+  }
-    success.setProperties(player.getGameProfileProperties());
-    success.setUuid(playerUniqueId);
-    mcConnection.write(success);
 
+  @Override
+  public boolean handle(LoginAcknowledged packet) {
+    if (loginState != State.SUCCESS_SENT) {
+      inbound.disconnect(Component.translatable("multiplayer.disconnect.invalid_player_data"));
+    } else {
+      loginState = State.ACKNOWLEDGED;
+      mcConnection.setActiveSessionHandler(StateRegistry.CONFIG,
+          new ClientConfigSessionHandler(server, connectedPlayer));
+
+      server.getEventManager().fire(new PostLoginEvent(connectedPlayer))
+          .thenCompose((ignored) -> connectToInitialServer(connectedPlayer)).exceptionally((ex) -> {
+            logger.error("Exception while connecting {} to initial server", connectedPlayer, ex);
+            return null;
+          });
+    }
+    return true;
+  }
+
+  private void completeLoginProtocolPhaseAndInitialize(ConnectedPlayer player) {
     mcConnection.setAssociation(player);
-    mcConnection.setState(StateRegistry.PLAY);
 
-    server.getEventManager().fire(new LoginEvent(player))
+    server.getEventManager().fire(new LoginEvent(player)).thenAcceptAsync(event -> {
-        .thenAcceptAsync(event -> {
       if (mcConnection.isClosed()) {
         // The player was disconnected
         server.getEventManager().fireAndForget(new DisconnectEvent(player,
@@ -193,16 +209,25 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
           return;
         }
 
-            mcConnection.setSessionHandler(new InitialConnectSessionHandler(player, server));
+        ServerLoginSuccess success = new ServerLoginSuccess();
+        success.setUsername(player.getUsername());
+        success.setProperties(player.getGameProfileProperties());
+        success.setUuid(player.getUniqueId());
+        mcConnection.write(success);
+
+        loginState = State.SUCCESS_SENT;
+        if (inbound.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_20_2) < 0) {
+          loginState = State.ACKNOWLEDGED;
+          mcConnection.setActiveSessionHandler(StateRegistry.PLAY,
+              new InitialConnectSessionHandler(player, server));
           server.getEventManager().fire(new PostLoginEvent(player))
-                .thenCompose((ignored) -> connectToInitialServer(player))
+              .thenCompose((ignored) -> connectToInitialServer(player)).exceptionally((ex) -> {
-                .exceptionally((ex) -> {
                 logger.error("Exception while connecting {} to initial server", player, ex);
                 return null;
               });
         }
-        }, mcConnection.eventLoop())
+      }
-        .exceptionally((ex) -> {
+    }, mcConnection.eventLoop()).exceptionally((ex) -> {
       logger.error("Exception while completing login initialisation phase for {}", player, ex);
       return null;
     });
@@ -210,15 +235,15 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
 
   private CompletableFuture<Void> connectToInitialServer(ConnectedPlayer player) {
     Optional<RegisteredServer> initialFromConfig = player.getNextServerToTry();
-    PlayerChooseInitialServerEvent event = new PlayerChooseInitialServerEvent(player,
+    PlayerChooseInitialServerEvent event =
-        initialFromConfig.orElse(null));
+        new PlayerChooseInitialServerEvent(player, initialFromConfig.orElse(null));
 
-    return server.getEventManager().fire(event)
+    return server.getEventManager().fire(event).thenRunAsync(() -> {
-        .thenRunAsync(() -> {
       Optional<RegisteredServer> toTry = event.getInitialServer();
       if (!toTry.isPresent()) {
-            player.disconnect0(Component.translatable("velocity.error.no-available-servers",
+        player.disconnect0(
-                NamedTextColor.RED), true);
+            Component.translatable("velocity.error.no-available-servers", NamedTextColor.RED),
+            true);
         return;
       }
       player.createConnectionRequest(toTry.get()).fireAndForget();
@@ -237,4 +262,8 @@ public class AuthSessionHandler implements MinecraftSessionHandler {
     }
     this.inbound.cleanup();
   }
+
+  static enum State {
+    START, SUCCESS_SENT, ACKNOWLEDGED
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientConfigSessionHandler.java

@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.connection.client;
+
+import com.velocitypowered.proxy.VelocityServer;
+import com.velocitypowered.proxy.connection.MinecraftConnection;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.StateRegistry;
+import com.velocitypowered.proxy.protocol.packet.ClientSettings;
+import com.velocitypowered.proxy.protocol.packet.KeepAlive;
+import com.velocitypowered.proxy.protocol.packet.PluginMessage;
+import com.velocitypowered.proxy.protocol.packet.ResourcePackResponse;
+import com.velocitypowered.proxy.protocol.packet.config.FinishedUpdate;
+import io.netty.buffer.ByteBuf;
+import java.util.concurrent.CompletableFuture;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.format.NamedTextColor;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+/**
+ * Handles the client config stage.
+ */
+public class ClientConfigSessionHandler implements MinecraftSessionHandler {
+
+  private static final Logger logger = LogManager.getLogger(ClientConfigSessionHandler.class);
+  private final VelocityServer server;
+  private final ConnectedPlayer player;
+
+  private CompletableFuture<Void> configSwitchFuture;
+
+  /**
+   * Constructs a client config session handler.
+   *
+   * @param server the Velocity server instance
+   * @param player the player
+   */
+  public ClientConfigSessionHandler(VelocityServer server, ConnectedPlayer player) {
+    this.server = server;
+    this.player = player;
+  }
+
+  @Override
+  public void activated() {
+    configSwitchFuture = new CompletableFuture<>();
+  }
+
+  @Override
+  public void deactivated() {
+  }
+
+  @Override
+  public boolean handle(KeepAlive packet) {
+    VelocityServerConnection serverConnection = player.getConnectedServer();
+    if (serverConnection != null) {
+      Long sentTime = serverConnection.getPendingPings().remove(packet.getRandomId());
+      if (sentTime != null) {
+        MinecraftConnection smc = serverConnection.getConnection();
+        if (smc != null) {
+          player.setPing(System.currentTimeMillis() - sentTime);
+          smc.write(packet);
+        }
+      }
+    }
+    return true;
+  }
+
+  @Override
+  public boolean handle(ClientSettings packet) {
+    player.setClientSettingsPacket(packet);
+    return true;
+  }
+
+  @Override
+  public boolean handle(ResourcePackResponse packet) {
+    if (player.getConnectionInFlight() != null) {
+      player.getConnectionInFlight().ensureConnected().write(packet);
+    }
+    return player.onResourcePackResponse(packet.getStatus());
+  }
+
+  @Override
+  public boolean handle(FinishedUpdate packet) {
+    player.getConnection()
+        .setActiveSessionHandler(StateRegistry.PLAY, new ClientPlaySessionHandler(server, player));
+
+    configSwitchFuture.complete(null);
+    return true;
+  }
+
+  @Override
+  public void handleGeneric(MinecraftPacket packet) {
+    VelocityServerConnection serverConnection = player.getConnectedServer();
+    if (serverConnection == null) {
+      // No server connection yet, probably transitioning.
+      return;
+    }
+
+    MinecraftConnection smc = serverConnection.getConnection();
+    if (smc != null && serverConnection.getPhase().consideredComplete()) {
+      if (packet instanceof PluginMessage) {
+        ((PluginMessage) packet).retain();
+      }
+      smc.write(packet);
+    }
+  }
+
+  @Override
+  public void handleUnknown(ByteBuf buf) {
+    VelocityServerConnection serverConnection = player.getConnectedServer();
+    if (serverConnection == null) {
+      // No server connection yet, probably transitioning.
+      return;
+    }
+
+    MinecraftConnection smc = serverConnection.getConnection();
+    if (smc != null && !smc.isClosed() && serverConnection.getPhase().consideredComplete()) {
+      smc.write(buf.retain());
+    }
+  }
+
+  @Override
+  public void disconnected() {
+    player.teardown();
+  }
+
+  @Override
+  public void exception(Throwable throwable) {
+    player.disconnect(
+        Component.translatable("velocity.error.player-connection-error", NamedTextColor.RED));
+  }
+
+  /**
+   * Handles the backend finishing the config stage.
+   *
+   * @param serverConn the server connection
+   * @return a future that completes when the config stage is finished
+   */
+  public CompletableFuture<Void> handleBackendFinishUpdate(VelocityServerConnection serverConn) {
+    player.getConnection().write(new FinishedUpdate());
+    serverConn.ensureConnected().write(new FinishedUpdate());
+    return configSwitchFuture;
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -17,9 +17,6 @@
 
 package com.velocitypowered.proxy.connection.client;
 
-import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_13;
-import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_16;
-import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_8;
 import static com.velocitypowered.proxy.protocol.util.PluginMessageUtil.constructChannelsPacket;
 
 import com.google.common.collect.ImmutableList;
@@ -67,6 +64,7 @@ import com.velocitypowered.proxy.protocol.packet.chat.session.SessionChatHandler
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionCommandHandler;
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionPlayerChat;
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionPlayerCommand;
+import com.velocitypowered.proxy.protocol.packet.config.FinishedUpdate;
 import com.velocitypowered.proxy.protocol.packet.title.GenericTitlePacket;
 import com.velocitypowered.proxy.protocol.util.PluginMessageUtil;
 import com.velocitypowered.proxy.util.CharacterUtil;
@@ -80,6 +78,7 @@ import java.util.Collection;
 import java.util.List;
 import java.util.Queue;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ConcurrentLinkedQueue;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
@@ -105,6 +104,8 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
   private final CommandHandler<? extends MinecraftPacket> commandHandler;
   private final ChatTimeKeeper timeKeeper = new ChatTimeKeeper();
 
+  private CompletableFuture<Void> configSwitchFuture;
+
   /**
    * Constructs a client play session handler.
    *
@@ -151,8 +152,9 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
   @Override
   public void activated() {
-    Collection<String> channels = server.getChannelRegistrar()
+    configSwitchFuture = new CompletableFuture<>();
-        .getChannelsForProtocol(player.getProtocolVersion());
+    Collection<String> channels =
+        server.getChannelRegistrar().getChannelsForProtocol(player.getProtocolVersion());
     if (!channels.isEmpty()) {
       PluginMessage register = constructChannelsPacket(player.getProtocolVersion(), channels);
       player.getConnection().write(register);
@@ -185,7 +187,13 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
   @Override
   public boolean handle(ClientSettings packet) {
     player.setPlayerSettings(packet);
-    return false; // will forward onto the server
+    VelocityServerConnection serverConnection = player.getConnectedServer();
+    if (serverConnection == null) {
+      // No server connection yet, probably transitioning.
+      return true;
+    }
+    player.getConnectedServer().ensureConnected().write(packet);
+    return true; // will forward onto the server
   }
 
   @Override
@@ -288,10 +296,8 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     MinecraftConnection backendConn = serverConn != null ? serverConn.getConnection() : null;
     if (serverConn != null && backendConn != null) {
       if (backendConn.getState() != StateRegistry.PLAY) {
-        logger.warn(
+        logger.warn("A plugin message was received while the backend server was not "
-            "A plugin message was received while the backend server was not "
+            + "ready. Channel: {}. Packet discarded.", packet.getChannel());
-                + "ready. Channel: {}. Packet discarded.",
-            packet.getChannel());
       } else if (PluginMessageUtil.isRegister(packet)) {
         List<String> channels = PluginMessageUtil.getChannels(packet);
         List<ChannelIdentifier> channelIdentifiers = new ArrayList<>();
@@ -377,6 +383,26 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     return player.onResourcePackResponse(packet.getStatus());
   }
 
+  @Override
+  public boolean handle(FinishedUpdate packet) {
+    // Complete client switch
+    player.getConnection().setActiveSessionHandler(StateRegistry.CONFIG);
+    VelocityServerConnection serverConnection = player.getConnectedServer();
+    if (serverConnection != null) {
+      MinecraftConnection smc = serverConnection.ensureConnected();
+      CompletableFuture.runAsync(() -> {
+        smc.write(packet);
+        smc.setActiveSessionHandler(StateRegistry.CONFIG);
+        smc.setAutoReading(true);
+      }, smc.eventLoop()).exceptionally((ex) -> {
+        logger.error("Error forwarding config state acknowledgement to server:", ex);
+        return null;
+      });
+    }
+    configSwitchFuture.complete(null);
+    return true;
+  }
+
   @Override
   public void handleGeneric(MinecraftPacket packet) {
     VelocityServerConnection serverConnection = player.getConnectedServer();
@@ -440,6 +466,33 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     }
   }
 
+  /**
+   * Handles switching stages for swapping between servers.
+   *
+   * @return a future that completes when the switch is complete
+   */
+  public CompletableFuture<Void> doSwitch() {
+    VelocityServerConnection existingConnection = player.getConnectedServer();
+
+    if (existingConnection != null) {
+      // Shut down the existing server connection.
+      player.setConnectedServer(null);
+      existingConnection.disconnect();
+
+      // Send keep alive to try to avoid timeouts
+      player.sendKeepAlive();
+
+      // Reset Tablist header and footer to prevent desync
+      player.clearHeaderAndFooter();
+    }
+
+    spawned = false;
+
+    player.switchToConfigState();
+
+    return configSwitchFuture;
+  }
+
   /**
    * Handles the {@code JoinGame} packet. This function is responsible for handling the client-side
    * switching servers in Velocity.
@@ -482,14 +535,6 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     }
     serverBossBars.clear();
 
-    // Tell the server about the proxy's plugin message channels.
-    ProtocolVersion serverVersion = serverMc.getProtocolVersion();
-    final Collection<String> channels = server.getChannelRegistrar()
-        .getChannelsForProtocol(serverMc.getProtocolVersion());
-    if (!channels.isEmpty()) {
-      serverMc.delayedWrite(constructChannelsPacket(serverVersion, channels));
-    }
-
     // If we had plugin messages queued during login/FML handshake, send them now.
     PluginMessage pm;
     while ((pm = loginPluginMessages.poll()) != null) {
@@ -497,7 +542,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     }
 
     // Clear any title from the previous server.
-    if (player.getProtocolVersion().compareTo(MINECRAFT_1_8) >= 0) {
+    if (player.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_8) >= 0) {
       player.getConnection().delayedWrite(
           GenericTitlePacket.constructTitlePacket(GenericTitlePacket.ActionType.RESET,
               player.getProtocolVersion()));
@@ -520,7 +565,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     // improving compatibility with mods.
     final Respawn respawn = Respawn.fromJoinGame(joinGame);
 
-    if (player.getProtocolVersion().compareTo(MINECRAFT_1_16) < 0) {
+    if (player.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_16) < 0) {
       // Before Minecraft 1.16, we could not switch to the same dimension without sending an
       // additional respawn. On older versions of Minecraft this forces the client to perform
       // garbage collection which adds additional latency.
@@ -562,7 +607,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
     String commandLabel = command.substring(0, commandEndPosition);
     if (!server.getCommandManager().hasCommand(commandLabel)) {
-      if (player.getProtocolVersion().compareTo(MINECRAFT_1_13) < 0) {
+      if (player.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_13) < 0) {
         // Outstanding tab completes are recorded for use with 1.12 clients and below to provide
         // additional tab completion support.
         outstandingTabComplete = packet;
@@ -604,7 +649,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
   }
 
   private boolean handleRegularTabComplete(TabCompleteRequest packet) {
-    if (player.getProtocolVersion().compareTo(MINECRAFT_1_13) < 0) {
+    if (player.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_13) < 0) {
       // Outstanding tab completes are recorded for use with 1.12 clients and below to provide
       // additional tab completion support.
       outstandingTabComplete = packet;
@@ -635,7 +680,8 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     String command = request.getCommand().substring(1);
     server.getCommandManager().offerBrigadierSuggestions(player, command)
         .thenAcceptAsync(offers -> {
-          boolean legacy = player.getProtocolVersion().compareTo(MINECRAFT_1_13) < 0;
+          boolean legacy =
+              player.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_13) < 0;
           try {
             for (Suggestion suggestion : offers.getList()) {
               String offer = suggestion.getText();
@@ -659,9 +705,9 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
           }
         }, player.getConnection().eventLoop()).exceptionally((ex) -> {
           logger.error(
-              "Exception while finishing command tab completion, with request {} and response {}",
+              "Exception while finishing command tab completion,"
-              request,
+                  + " with request {} and response {}",
-              response, ex);
+              request, response, ex);
           return null;
         });
   }
@@ -680,9 +726,9 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
           player.getConnection().write(response);
         }, player.getConnection().eventLoop()).exceptionally((ex) -> {
           logger.error(
-              "Exception while finishing regular tab completion, with request {} and response{}",
+              "Exception while finishing regular tab completion,"
-              request,
+                  + " with request {} and response{}",
-              response, ex);
+              request, response, ex);
           return null;
         });
   }
@@ -702,5 +748,4 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
       }
     }
   }
-
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -59,6 +59,7 @@ import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
 import com.velocitypowered.proxy.connection.util.VelocityInboundConnection;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import com.velocitypowered.proxy.protocol.StateRegistry;
+import com.velocitypowered.proxy.protocol.netty.MinecraftEncoder;
 import com.velocitypowered.proxy.protocol.packet.ClientSettings;
 import com.velocitypowered.proxy.protocol.packet.Disconnect;
 import com.velocitypowered.proxy.protocol.packet.HeaderAndFooter;
@@ -69,6 +70,7 @@ import com.velocitypowered.proxy.protocol.packet.chat.ChatQueue;
 import com.velocitypowered.proxy.protocol.packet.chat.ChatType;
 import com.velocitypowered.proxy.protocol.packet.chat.builder.ChatBuilderFactory;
 import com.velocitypowered.proxy.protocol.packet.chat.legacy.LegacyChat;
+import com.velocitypowered.proxy.protocol.packet.config.StartUpdate;
 import com.velocitypowered.proxy.protocol.packet.title.GenericTitlePacket;
 import com.velocitypowered.proxy.server.VelocityRegisteredServer;
 import com.velocitypowered.proxy.tablist.InternalTabList;
@@ -123,12 +125,9 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
 
   private static final int MAX_PLUGIN_CHANNELS = 1024;
   private static final PlainTextComponentSerializer PASS_THRU_TRANSLATE =
-      PlainTextComponentSerializer.builder()
+      PlainTextComponentSerializer.builder().flattener(
-          .flattener(ComponentFlattener.basic().toBuilder()
+          ComponentFlattener.basic().toBuilder().mapper(KeybindComponent.class, c -> "")
-              .mapper(KeybindComponent.class, c -> "")
+              .mapper(TranslatableComponent.class, TranslatableComponent::key).build()).build();
-              .mapper(TranslatableComponent.class, TranslatableComponent::key)
-              .build())
-          .build();
   static final PermissionProvider DEFAULT_PERMISSIONS = s -> PermissionFunction.ALWAYS_UNDEFINED;
 
   private static final Logger logger = LogManager.getLogger(ConnectedPlayer.class);
@@ -159,17 +158,17 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
   private final Queue<ResourcePackInfo> outstandingResourcePacks = new ArrayDeque<>();
   private @Nullable ResourcePackInfo pendingResourcePack;
   private @Nullable ResourcePackInfo appliedResourcePack;
-  private final @NotNull Pointers pointers = Player.super.pointers().toBuilder()
+  private final @NotNull Pointers pointers =
-      .withDynamic(Identity.UUID, this::getUniqueId)
+      Player.super.pointers().toBuilder().withDynamic(Identity.UUID, this::getUniqueId)
           .withDynamic(Identity.NAME, this::getUsername)
           .withDynamic(Identity.DISPLAY_NAME, () -> Component.text(this.getUsername()))
           .withDynamic(Identity.LOCALE, this::getEffectiveLocale)
           .withStatic(PermissionChecker.POINTER, getPermissionChecker())
-      .withStatic(FacetPointers.TYPE, Type.PLAYER)
+          .withStatic(FacetPointers.TYPE, Type.PLAYER).build();
-      .build();
   private @Nullable String clientBrand;
   private @Nullable Locale effectiveLocale;
   private @Nullable IdentifiedKey playerKey;
+  private @Nullable ClientSettings clientSettingsPacket;
   private final ChatQueue chatQueue;
   private final ChatBuilderFactory chatBuilderFactory;
 
@@ -278,11 +277,19 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
     return settings == null ? ClientSettingsWrapper.DEFAULT : this.settings;
   }
 
+  public ClientSettings getClientSettingsPacket() {
+    return clientSettingsPacket;
+  }
+
   @Override
   public boolean hasSentPlayerSettings() {
     return settings != null;
   }
 
+  public void setClientSettingsPacket(ClientSettings clientSettingsPacket) {
+    this.clientSettingsPacket = clientSettingsPacket;
+  }
+
   void setPlayerSettings(ClientSettings settings) {
     ClientSettingsWrapper cs = new ClientSettingsWrapper(settings);
     this.settings = cs;
@@ -674,8 +681,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
     ServerKickResult result;
     if (kickedFromCurrent) {
       Optional<RegisteredServer> next = getNextServerToTry(rs);
-      result = next.map(RedirectPlayer::create)
+      result =
-          .orElseGet(() -> DisconnectPlayer.create(friendlyReason));
+          next.map(RedirectPlayer::create).orElseGet(() -> DisconnectPlayer.create(friendlyReason));
     } else {
       // If we were kicked by going to another server, the connection should not be in flight
       if (connectionInFlight != null && connectionInFlight.getServer().equals(rs)) {
@@ -690,8 +697,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
 
   private void handleKickEvent(KickedFromServerEvent originalEvent, Component friendlyReason,
                                boolean kickedFromCurrent) {
-    server.getEventManager().fire(originalEvent)
+    server.getEventManager().fire(originalEvent).thenAcceptAsync(event -> {
-        .thenAcceptAsync(event -> {
       // There can't be any connection in flight now.
       connectionInFlight = null;
 
@@ -711,22 +717,20 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
         disconnect(res.getReasonComponent());
       } else if (event.getResult() instanceof RedirectPlayer) {
         RedirectPlayer res = (RedirectPlayer) event.getResult();
-            createConnectionRequest(res.getServer(), previousConnection)
+        createConnectionRequest(res.getServer(), previousConnection).connect()
-                .connect()
             .whenCompleteAsync((status, throwable) -> {
               if (throwable != null) {
-                    handleConnectionException(status != null ? status.getAttemptedConnection()
+                handleConnectionException(
-                        : res.getServer(), throwable, true);
+                    status != null ? status.getAttemptedConnection() : res.getServer(), throwable,
+                    true);
                 return;
               }
 
               switch (status.getStatus()) {
                 // Impossible/nonsensical cases
                 case ALREADY_CONNECTED:
-                      logger.error("{}: already connected to {}",
+                  logger.error("{}: already connected to {}", this,
-                          this,
+                      status.getAttemptedConnection().getServerInfo().getName());
-                          status.getAttemptedConnection().getServerInfo().getName()
-                      );
                   break;
                 case CONNECTION_IN_PROGRESS:
                   // Fatal case
@@ -740,8 +744,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
                 case SERVER_DISCONNECTED:
                   Component reason = status.getReasonComponent()
                       .orElse(ConnectionMessages.INTERNAL_SERVER_CONNECTION_ERROR);
-                      handleConnectionException(res.getServer(), Disconnect.create(reason,
+                  handleConnectionException(res.getServer(),
-                          getProtocolVersion()), ((Impl) status).isSafe());
+                      Disconnect.create(reason, getProtocolVersion()), ((Impl) status).isSafe());
                   break;
                 case SUCCESS:
                   Component requestedMessage = res.getMessageComponent();
@@ -1021,6 +1025,13 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
     return pendingResourcePack;
   }
 
+  /**
+   * Clears the applied resource pack field.
+   */
+  public void clearAppliedResourcePack() {
+    appliedResourcePack = null;
+  }
+
   /**
    * Processes a client response to a sent resource-pack.
    */
@@ -1068,18 +1079,42 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
         && queued.getOriginalOrigin() != ResourcePackInfo.Origin.DOWNSTREAM_SERVER;
   }
 
+  /**
+   * Gives an indication about the previous resource pack responses.
+   */
+  public @Nullable Boolean getPreviousResourceResponse() {
+    return previousResourceResponse;
+  }
+
   /**
    * Sends a {@link KeepAlive} packet to the player with a random ID. The response will be ignored
    * by Velocity as it will not match the ID last sent by the server.
    */
   public void sendKeepAlive() {
-    if (connection.getState() == StateRegistry.PLAY) {
+    if (connection.getState() == StateRegistry.PLAY
+            || connection.getState() == StateRegistry.CONFIG) {
       KeepAlive keepAlive = new KeepAlive();
       keepAlive.setRandomId(ThreadLocalRandom.current().nextLong());
       connection.write(keepAlive);
     }
   }
 
+  /**
+   * Switches the connection to the client into config state.
+   */
+  public void switchToConfigState() {
+    CompletableFuture.runAsync(() -> {
+      connection.write(new StartUpdate());
+      connection.getChannel().pipeline()
+              .get(MinecraftEncoder.class).setState(StateRegistry.CONFIG);
+      // Make sure we don't send any play packets to the player after update start
+      connection.addPlayPacketQueueHandler();
+    }, connection.eventLoop()).exceptionally((ex) -> {
+      logger.error("Error switching player connection to config state:", ex);
+      return null;
+    });
+  }
+
   /**
    * Gets the current "phase" of the connection, mostly used for tracking modded negotiation for
    * legacy forge servers and provides methods for performing phase specific actions.
@@ -1147,21 +1182,18 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
     }
 
     private CompletableFuture<Impl> internalConnect() {
-      return this.getInitialStatus()
+      return this.getInitialStatus().thenCompose(initialCheck -> {
-          .thenCompose(initialCheck -> {
         if (initialCheck.isPresent()) {
           return completedFuture(plainResult(initialCheck.get(), toConnect));
         }
 
-            ServerPreConnectEvent event = new ServerPreConnectEvent(ConnectedPlayer.this,
+        ServerPreConnectEvent event =
-                toConnect, previousServer);
+            new ServerPreConnectEvent(ConnectedPlayer.this, toConnect, previousServer);
-            return server.getEventManager().fire(event)
+        return server.getEventManager().fire(event).thenComposeAsync(newEvent -> {
-                .thenComposeAsync(newEvent -> {
           Optional<RegisteredServer> newDest = newEvent.getResult().getServer();
           if (!newDest.isPresent()) {
             return completedFuture(
-                        plainResult(ConnectionRequestBuilder.Status.CONNECTION_CANCELLED, toConnect)
+                plainResult(ConnectionRequestBuilder.Status.CONNECTION_CANCELLED, toConnect));
-                    );
           }
 
           RegisteredServer realDestination = newDest.get();
@@ -1171,11 +1203,11 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
           }
 
           VelocityRegisteredServer vrs = (VelocityRegisteredServer) realDestination;
-                  VelocityServerConnection con = new VelocityServerConnection(vrs,
+          VelocityServerConnection con =
-                      previousServer, ConnectedPlayer.this, server);
+              new VelocityServerConnection(vrs, previousServer, ConnectedPlayer.this, server);
           connectionInFlight = con;
-                  return con.connect().whenCompleteAsync(
+          return con.connect().whenCompleteAsync((result, exception) -> this.resetIfInFlightIs(con),
-                      (result, exception) -> this.resetIfInFlightIs(con), connection.eventLoop());
+              connection.eventLoop());
         }, connection.eventLoop());
       });
     }
@@ -1188,25 +1220,22 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
 
     @Override
     public CompletableFuture<Result> connect() {
-      return this.internalConnect()
+      return this.internalConnect().whenCompleteAsync((status, throwable) -> {
-          .whenCompleteAsync((status, throwable) -> {
         if (status != null && !status.isSuccessful()) {
           if (!status.isSafe()) {
             handleConnectionException(status.getAttemptedConnection(), throwable, false);
           }
         }
-          }, connection.eventLoop())
+      }, connection.eventLoop()).thenApply(x -> x);
-          .thenApply(x -> x);
     }
 
     @Override
     public CompletableFuture<Boolean> connectWithIndication() {
-      return internalConnect()
+      return internalConnect().whenCompleteAsync((status, throwable) -> {
-          .whenCompleteAsync((status, throwable) -> {
         if (throwable != null) {
           // TODO: The exception handling from this is not very good. Find a better way.
-              handleConnectionException(status != null ? status.getAttemptedConnection()
+          handleConnectionException(status != null ? status.getAttemptedConnection() : toConnect,
-                  : toConnect, throwable, true);
+              throwable, true);
           return;
         }
 
@@ -1223,15 +1252,14 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
           case SERVER_DISCONNECTED:
             Component reason = status.getReasonComponent()
                 .orElse(ConnectionMessages.INTERNAL_SERVER_CONNECTION_ERROR);
-                handleConnectionException(toConnect, Disconnect.create(reason,
+            handleConnectionException(toConnect, Disconnect.create(reason, getProtocolVersion()),
-                    getProtocolVersion()), status.isSafe());
+                status.isSafe());
             break;
           default:
             // The only remaining value is successful (no need to do anything!)
             break;
         }
-          }, connection.eventLoop())
+      }, connection.eventLoop()).thenApply(Result::isSuccessful);
-          .thenApply(Result::isSuccessful);
     }
 
     @Override

proxy/src/main/java/com/velocitypowered/proxy/connection/client/HandshakeSessionHandler.java

@@ -47,8 +47,8 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * The initial handler used when a connection is established to the proxy. This will either
- * transition to {@link StatusSessionHandler} or {@link InitialLoginSessionHandler} as soon
+ * transition to {@link StatusSessionHandler} or {@link InitialLoginSessionHandler} as soon as the
- * as the handshake packet is received.
+ * handshake packet is received.
  */
 public class HandshakeSessionHandler implements MinecraftSessionHandler {
 
@@ -65,9 +65,9 @@ public class HandshakeSessionHandler implements MinecraftSessionHandler {
   @Override
   public boolean handle(LegacyPing packet) {
     connection.setProtocolVersion(ProtocolVersion.LEGACY);
-    StatusSessionHandler handler = new StatusSessionHandler(server,
+    StatusSessionHandler handler =
-        new LegacyInboundConnection(connection, packet));
+        new StatusSessionHandler(server, new LegacyInboundConnection(connection, packet));
-    connection.setSessionHandler(handler);
+    connection.setActiveSessionHandler(StateRegistry.STATUS, handler);
     handler.handle(packet);
     return true;
   }
@@ -90,13 +90,13 @@ public class HandshakeSessionHandler implements MinecraftSessionHandler {
       LOGGER.error("{} provided invalid protocol {}", ic, handshake.getNextStatus());
       connection.close(true);
     } else {
-      connection.setState(nextState);
       connection.setProtocolVersion(handshake.getProtocolVersion());
       connection.setAssociation(ic);
 
       switch (nextState) {
         case STATUS:
-          connection.setSessionHandler(new StatusSessionHandler(server, ic));
+          connection.setActiveSessionHandler(StateRegistry.STATUS,
+              new StatusSessionHandler(server, ic));
           break;
         case LOGIN:
           this.handleLogin(handshake, ic);
@@ -140,14 +140,15 @@ public class HandshakeSessionHandler implements MinecraftSessionHandler {
     // and lower, otherwise IP information will never get forwarded.
     if (server.getConfiguration().getPlayerInfoForwardingMode() == PlayerInfoForwarding.MODERN
         && handshake.getProtocolVersion().compareTo(ProtocolVersion.MINECRAFT_1_13) < 0) {
-      ic.disconnectQuietly(Component.translatable(
+      ic.disconnectQuietly(
-          "velocity.error.modern-forwarding-needs-new-client"));
+          Component.translatable("velocity.error.modern-forwarding-needs-new-client"));
       return;
     }
 
     LoginInboundConnection lic = new LoginInboundConnection(ic);
     server.getEventManager().fireAndForget(new ConnectionHandshakeEvent(lic));
-    connection.setSessionHandler(new InitialLoginSessionHandler(server, connection, lic));
+    connection.setActiveSessionHandler(StateRegistry.LOGIN,
+        new InitialLoginSessionHandler(server, connection, lic));
   }
 
   private ConnectionType getHandshakeConnectionType(Handshake handshake) {

proxy/src/main/java/com/velocitypowered/proxy/connection/client/InitialLoginSessionHandler.java

@@ -34,6 +34,7 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.crypto.IdentifiedKeyImpl;
+import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.packet.EncryptionRequest;
 import com.velocitypowered.proxy.protocol.packet.EncryptionResponse;
@@ -120,8 +121,7 @@ public class InitialLoginSessionHandler implements MinecraftSessionHandler {
     this.login = packet;
 
     PreLoginEvent event = new PreLoginEvent(inbound, login.getUsername());
-    server.getEventManager().fire(event)
+    server.getEventManager().fire(event).thenRunAsync(() -> {
-        .thenRunAsync(() -> {
       if (mcConnection.isClosed()) {
         // The player was disconnected
         return;
@@ -142,22 +142,21 @@ public class InitialLoginSessionHandler implements MinecraftSessionHandler {
         }
 
         mcConnection.eventLoop().execute(() -> {
-              if (!result.isForceOfflineMode() && (server.getConfiguration().isOnlineMode()
+          if (!result.isForceOfflineMode()
-                  || result.isOnlineModeAllowed())) {
+              && (server.getConfiguration().isOnlineMode() || result.isOnlineModeAllowed())) {
             // Request encryption.
             EncryptionRequest request = generateEncryptionRequest();
             this.verify = Arrays.copyOf(request.getVerifyToken(), 4);
             mcConnection.write(request);
             this.currentState = LoginState.ENCRYPTION_REQUEST_SENT;
           } else {
-                mcConnection.setSessionHandler(new AuthSessionHandler(
+            mcConnection.setActiveSessionHandler(StateRegistry.LOGIN,
-                    server, inbound, GameProfile.forOfflinePlayer(login.getUsername()), false
+                new AuthSessionHandler(server, inbound,
-                ));
+                    GameProfile.forOfflinePlayer(login.getUsername()), false));
           }
         });
       });
-        }, mcConnection.eventLoop())
+    }, mcConnection.eventLoop()).exceptionally((ex) -> {
-        .exceptionally((ex) -> {
       logger.error("Exception in pre-login stage", ex);
       return null;
     });
@@ -246,13 +245,12 @@ public class InitialLoginSessionHandler implements MinecraftSessionHandler {
               }
             }
             // All went well, initialize the session.
-            mcConnection.setSessionHandler(new AuthSessionHandler(
+            mcConnection.setActiveSessionHandler(StateRegistry.LOGIN,
-                server, inbound, profile, true
+                new AuthSessionHandler(server, inbound, profile, true));
-            ));
           } else if (profileResponse.getStatusCode() == 204) {
             // Apparently an offline-mode user logged onto this online-mode proxy.
-            inbound.disconnect(Component.translatable("velocity.error.online-mode-only",
+            inbound.disconnect(
-                NamedTextColor.RED));
+                Component.translatable("velocity.error.online-mode-only", NamedTextColor.RED));
           } else {
             // Something else went wrong
             logger.error(

proxy/src/main/java/com/velocitypowered/proxy/connection/forge/legacy/LegacyForgeHandshakeClientPhase.java

@@ -76,9 +76,9 @@ public enum LegacyForgeHandshakeClientPhase implements ClientConnectionPhase {
   },
 
   /**
-   * The Mod list is sent to the server, captured by Velocity. Transition to
+   * The Mod list is sent to the server, captured by Velocity. Transition to {@link
-   * {@link #WAITING_SERVER_DATA} when an ACK is sent, which indicates to the server to start
+   * #WAITING_SERVER_DATA} when an ACK is sent, which indicates to the server to start sending state
-   * sending state data.
+   * data.
    */
   MOD_LIST(LegacyForgeConstants.ACK_DISCRIMINATOR) {
     @Override
@@ -138,11 +138,10 @@ public enum LegacyForgeHandshakeClientPhase implements ClientConnectionPhase {
   /**
    * The handshake is complete. The handshake can be reset.
    *
-   * <p>Note that a successful connection to a server does not mean that
+   * <p>Note that a successful connection to a server does not mean that we will be in this state.
-   * we will be in this state. After a handshake reset, if the next server is vanilla we will still
+   * After a handshake reset, if the next server is vanilla we will still be in the {@link
-   * be in the {@link #NOT_STARTED} phase, which means we must NOT send a reset packet. This is
+   * #NOT_STARTED} phase, which means we must NOT send a reset packet. This is handled by overriding
-   * handled by overriding the {@link #resetConnectionPhase(ConnectedPlayer)} in this element (it is
+   * the {@link #resetConnectionPhase(ConnectedPlayer)} in this element (it is usually a no-op).
-   * usually a no-op).</p>
    */
   COMPLETE(null) {
     @Override
@@ -165,7 +164,7 @@ public enum LegacyForgeHandshakeClientPhase implements ClientConnectionPhase {
       // just in case the timing is awful
       player.sendKeepAlive();
 
-      MinecraftSessionHandler handler = backendConn.getSessionHandler();
+      MinecraftSessionHandler handler = backendConn.getActiveSessionHandler();
       if (handler instanceof ClientPlaySessionHandler) {
         ((ClientPlaySessionHandler) handler).flushQueuedMessages();
       }
@@ -182,8 +181,8 @@ public enum LegacyForgeHandshakeClientPhase implements ClientConnectionPhase {
    *
    * @param packetToAdvanceOn The ID of the packet discriminator that indicates that the client has
    *                          moved onto a new phase, and as such, Velocity should do so too
-   *                          (inspecting {@link #nextPhase()}. A null indicates there is no further
+   *                          (inspecting {@link #nextPhase()}. A null indicates there is
-   *                          phase to transition to.
+   *                          no further phase to transition to.
    */
   LegacyForgeHandshakeClientPhase(Integer packetToAdvanceOn) {
     this.packetToAdvanceOn = packetToAdvanceOn;

proxy/src/main/java/com/velocitypowered/proxy/connection/registry/ClientConfigData.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.connection.registry;
+
+import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.protocol.packet.config.RegistrySync;
+import net.kyori.adventure.key.Key;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Holds the registry data that is sent
+ * to the client during the config stage.
+ */
+public class ClientConfigData {
+
+  private final @Nullable VelocityResourcePackInfo resourcePackInfo;
+  private final DataTag tag;
+  private final RegistrySync registry;
+  private final Key[] features;
+  private final String brand;
+
+  private ClientConfigData(@Nullable VelocityResourcePackInfo resourcePackInfo, DataTag tag,
+                           RegistrySync registry, Key[] features, String brand) {
+    this.resourcePackInfo = resourcePackInfo;
+    this.tag = tag;
+    this.registry = registry;
+    this.features = features;
+    this.brand = brand;
+  }
+
+  public RegistrySync getRegistry() {
+    return registry;
+  }
+
+  public DataTag getTag() {
+    return tag;
+  }
+
+  public Key[] getFeatures() {
+    return features;
+  }
+
+  public @Nullable VelocityResourcePackInfo getResourcePackInfo() {
+    return resourcePackInfo;
+  }
+
+  public String getBrand() {
+    return brand;
+  }
+
+  /**
+   * Creates a new builder.
+   *
+   * @return ClientConfigData.Builder
+   */
+  public static ClientConfigData.Builder builder() {
+    return new Builder();
+  }
+
+  /**
+   * Builder for ClientConfigData.
+   */
+  public static class Builder {
+    private VelocityResourcePackInfo resourcePackInfo;
+    private DataTag tag;
+    private RegistrySync registry;
+    private Key[] features;
+    private String brand;
+
+    private Builder() {
+    }
+
+    /**
+     * Clears the builder.
+     */
+    public void clear() {
+      this.resourcePackInfo = null;
+      this.tag = null;
+      this.registry = null;
+      this.features = null;
+      this.brand = null;
+    }
+
+    public Builder resourcePack(@Nullable VelocityResourcePackInfo resourcePackInfo) {
+      this.resourcePackInfo = resourcePackInfo;
+      return this;
+    }
+
+    public Builder dataTag(DataTag tag) {
+      this.tag = tag;
+      return this;
+    }
+
+    public Builder registry(RegistrySync registry) {
+      this.registry = registry;
+      return this;
+    }
+
+    public Builder features(Key[] features) {
+      this.features = features;
+      return this;
+    }
+
+    public Builder brand(String brand) {
+      this.brand = brand;
+      return this;
+    }
+
+    public ClientConfigData build() {
+      return new ClientConfigData(resourcePackInfo, tag, registry, features, brand);
+    }
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/connection/registry/DataTag.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2019-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.connection.registry;
+
+import com.google.common.collect.ImmutableList;
+import java.util.List;
+import net.kyori.adventure.key.Key;
+import net.kyori.adventure.key.Keyed;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Represents a data tag.
+ */
+public class DataTag {
+  private final ImmutableList<DataTag.Set> entrySets;
+
+  public DataTag(ImmutableList<DataTag.Set> entrySets) {
+    this.entrySets = entrySets;
+  }
+
+  /**
+   * Returns the entry sets.
+   *
+   * @return List of entry sets
+   */
+  public List<Set> getEntrySets() {
+    return entrySets;
+  }
+
+  /**
+   * Represents a data tag set.
+   */
+  public static class Set implements Keyed {
+
+    private final Key key;
+    private final ImmutableList<Entry> entries;
+
+    public Set(Key key, ImmutableList<Entry> entries) {
+      this.key = key;
+      this.entries = entries;
+    }
+
+    /**
+     * Returns the entries.
+     *
+     * @return List of entries
+     */
+    public List<Entry> getEntries() {
+      return entries;
+    }
+
+    @Override
+    public @NotNull Key key() {
+      return key;
+    }
+  }
+
+  /**
+   * Represents a data tag entry.
+   */
+  public static class Entry implements Keyed {
+
+    private final Key key;
+    private final int[] elements;
+
+    public Entry(Key key, int[] elements) {
+      this.key = key;
+      this.elements = elements;
+    }
+
+    public int[] getElements() {
+      return elements;
+    }
+
+    @Override
+    public @NotNull Key key() {
+      return key;
+    }
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/network/Connections.java

@@ -35,6 +35,7 @@ public class Connections {
   public static final String MINECRAFT_DECODER = "minecraft-decoder";
   public static final String MINECRAFT_ENCODER = "minecraft-encoder";
   public static final String READ_TIMEOUT = "read-timeout";
+  public static final String PLAY_PACKET_QUEUE = "play-packet-queue";
 
   private Connections() {
     throw new AssertionError();

proxy/src/main/java/com/velocitypowered/proxy/network/ServerChannelInitializer.java

@@ -29,6 +29,7 @@ import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.client.HandshakeSessionHandler;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.netty.LegacyPingDecoder;
 import com.velocitypowered.proxy.protocol.netty.LegacyPingEncoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
@@ -67,7 +68,8 @@ public class ServerChannelInitializer extends ChannelInitializer<Channel> {
         .addLast(MINECRAFT_ENCODER, new MinecraftEncoder(ProtocolUtils.Direction.CLIENTBOUND));
 
     final MinecraftConnection connection = new MinecraftConnection(ch, this.server);
-    connection.setSessionHandler(new HandshakeSessionHandler(connection, this.server));
+    connection.setActiveSessionHandler(StateRegistry.HANDSHAKE,
+        new HandshakeSessionHandler(connection, this.server));
     ch.pipeline().addLast(Connections.HANDLER, connection);
 
     if (this.server.getConfiguration().isProxyProtocol()) {

proxy/src/main/java/com/velocitypowered/proxy/protocol/ProtocolUtils.java

@@ -41,6 +41,7 @@ import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
+import net.kyori.adventure.key.Key;
 import net.kyori.adventure.nbt.BinaryTagIO;
 import net.kyori.adventure.nbt.CompoundBinaryTag;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
@@ -202,8 +203,7 @@ public enum ProtocolUtils {
         buf.readableBytes());
     String str = buf.toString(buf.readerIndex(), length, StandardCharsets.UTF_8);
     buf.skipBytes(length);
-    checkFrame(str.length() <= cap, "Got a too-long string (got %s, max %s)",
+    checkFrame(str.length() <= cap, "Got a too-long string (got %s, max %s)", str.length(), cap);
-        str.length(), cap);
     return str;
   }
 
@@ -219,6 +219,59 @@ public enum ProtocolUtils {
     buf.writeCharSequence(str, StandardCharsets.UTF_8);
   }
 
+  /**
+   * Reads a standard Mojang Text namespaced:key from the buffer.
+   *
+   * @param buf the buffer to read from
+   * @return the decoded key
+   */
+  public static Key readKey(ByteBuf buf) {
+    return Key.key(readString(buf), Key.DEFAULT_SEPARATOR);
+  }
+
+  /**
+   * Writes a standard Mojang Text namespaced:key to the buffer.
+   *
+   * @param buf the buffer to write to
+   * @param key the key to write
+   */
+  public static void writeKey(ByteBuf buf, Key key) {
+    writeString(buf, key.asString());
+  }
+
+  /**
+   * Reads a standard Mojang Text namespaced:key array from the buffer.
+   *
+   * @param buf the buffer to read from
+   * @return the decoded key array
+   */
+  public static Key[] readKeyArray(ByteBuf buf) {
+    int length = readVarInt(buf);
+    checkFrame(length >= 0, "Got a negative-length array (%s)", length);
+    checkFrame(buf.isReadable(length),
+        "Trying to read an array that is too long (wanted %s, only have %s)", length,
+        buf.readableBytes());
+    Key[] ret = new Key[length];
+
+    for (int i = 0; i < ret.length; i++) {
+      ret[i] = ProtocolUtils.readKey(buf);
+    }
+    return ret;
+  }
+
+  /**
+   * Writes a standard Mojang Text namespaced:key array to the buffer.
+   *
+   * @param buf  the buffer to write to
+   * @param keys the keys to write
+   */
+  public static void writeKeyArray(ByteBuf buf, Key[] keys) {
+    writeVarInt(buf, keys.length);
+    for (Key key : keys) {
+      writeKey(buf, key);
+    }
+  }
+
   public static byte[] readByteArray(ByteBuf buf) {
     return readByteArray(buf, DEFAULT_MAX_STRING_SIZE);
   }
@@ -368,6 +421,38 @@ public enum ProtocolUtils {
     }
   }
 
+  /**
+   * Reads an Integer array from the {@code buf}.
+   *
+   * @param buf the buffer to read from
+   * @return the Integer array from the buffer
+   */
+  public static int[] readVarIntArray(ByteBuf buf) {
+    int length = readVarInt(buf);
+    checkFrame(length >= 0, "Got a negative-length array (%s)", length);
+    checkFrame(buf.isReadable(length),
+        "Trying to read an array that is too long (wanted %s, only have %s)", length,
+        buf.readableBytes());
+    int[] ret = new int[length];
+    for (int i = 0; i < length; i++) {
+      ret[i] = readVarInt(buf);
+    }
+    return ret;
+  }
+
+  /**
+   * Writes an Integer Array to the {@code buf}.
+   *
+   * @param buf      the buffer to write to
+   * @param intArray the array to write
+   */
+  public static void writeVarIntArray(ByteBuf buf, int[] intArray) {
+    writeVarInt(buf, intArray.length);
+    for (int i = 0; i < intArray.length; i++) {
+      writeVarInt(buf, intArray[i]);
+    }
+  }
+
   /**
    * Writes a list of {@link com.velocitypowered.api.util.GameProfile.Property} to the buffer.
    *

proxy/src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -33,6 +33,7 @@ import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_19;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_19_1;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_19_3;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_19_4;
+import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_20_2;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_7_2;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_8;
 import static com.velocitypowered.api.network.ProtocolVersion.MINECRAFT_1_9;
@@ -55,8 +56,10 @@ import com.velocitypowered.proxy.protocol.packet.HeaderAndFooter;
 import com.velocitypowered.proxy.protocol.packet.JoinGame;
 import com.velocitypowered.proxy.protocol.packet.KeepAlive;
 import com.velocitypowered.proxy.protocol.packet.LegacyPlayerListItem;
+import com.velocitypowered.proxy.protocol.packet.LoginAcknowledged;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginMessage;
 import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
+import com.velocitypowered.proxy.protocol.packet.PingIdentify;
 import com.velocitypowered.proxy.protocol.packet.PluginMessage;
 import com.velocitypowered.proxy.protocol.packet.RemovePlayerInfo;
 import com.velocitypowered.proxy.protocol.packet.ResourcePackRequest;
@@ -79,6 +82,11 @@ import com.velocitypowered.proxy.protocol.packet.chat.keyed.KeyedPlayerCommand;
 import com.velocitypowered.proxy.protocol.packet.chat.legacy.LegacyChat;
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionPlayerChat;
 import com.velocitypowered.proxy.protocol.packet.chat.session.SessionPlayerCommand;
+import com.velocitypowered.proxy.protocol.packet.config.ActiveFeatures;
+import com.velocitypowered.proxy.protocol.packet.config.FinishedUpdate;
+import com.velocitypowered.proxy.protocol.packet.config.RegistrySync;
+import com.velocitypowered.proxy.protocol.packet.config.StartUpdate;
+import com.velocitypowered.proxy.protocol.packet.config.TagsUpdate;
 import com.velocitypowered.proxy.protocol.packet.title.LegacyTitlePacket;
 import com.velocitypowered.proxy.protocol.packet.title.TitleActionbarPacket;
 import com.velocitypowered.proxy.protocol.packet.title.TitleClearPacket;
@@ -98,9 +106,7 @@ import java.util.Objects;
 import java.util.function.Supplier;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
-/**
+/** Registry of all Minecraft protocol states and the packets for each state. */
- * Registry of all Minecraft protocol states and the packets for each state.
- */
 public enum StateRegistry {
 
   HANDSHAKE {
@@ -111,15 +117,46 @@ public enum StateRegistry {
   },
   STATUS {
     {
-      serverbound.register(StatusRequest.class, () -> StatusRequest.INSTANCE,
+      serverbound.register(
-          map(0x00, MINECRAFT_1_7_2, false));
+          StatusRequest.class, () -> StatusRequest.INSTANCE, map(0x00, MINECRAFT_1_7_2, false));
-      serverbound.register(StatusPing.class, StatusPing::new,
+      serverbound.register(StatusPing.class, StatusPing::new, map(0x01, MINECRAFT_1_7_2, false));
-          map(0x01, MINECRAFT_1_7_2, false));
 
-      clientbound.register(StatusResponse.class, StatusResponse::new,
+      clientbound.register(
-          map(0x00, MINECRAFT_1_7_2, false));
+          StatusResponse.class, StatusResponse::new, map(0x00, MINECRAFT_1_7_2, false));
-      clientbound.register(StatusPing.class, StatusPing::new,
+      clientbound.register(StatusPing.class, StatusPing::new, map(0x01, MINECRAFT_1_7_2, false));
-          map(0x01, MINECRAFT_1_7_2, false));
+    }
+  },
+  CONFIG {
+    {
+      serverbound.register(
+          ClientSettings.class, ClientSettings::new, map(0x00, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          PluginMessage.class, PluginMessage::new, map(0x01, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          FinishedUpdate.class, FinishedUpdate::new, map(0x02, MINECRAFT_1_20_2, false));
+      serverbound.register(KeepAlive.class, KeepAlive::new, map(0x03, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          PingIdentify.class, PingIdentify::new, map(0x04, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          ResourcePackResponse.class,
+          ResourcePackResponse::new,
+          map(0x05, MINECRAFT_1_20_2, false));
+
+      clientbound.register(
+          PluginMessage.class, PluginMessage::new, map(0x00, MINECRAFT_1_20_2, false));
+      clientbound.register(Disconnect.class, Disconnect::new, map(0x01, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          FinishedUpdate.class, FinishedUpdate::new, map(0x02, MINECRAFT_1_20_2, false));
+      clientbound.register(KeepAlive.class, KeepAlive::new, map(0x03, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          PingIdentify.class, PingIdentify::new, map(0x04, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          RegistrySync.class, RegistrySync::new, map(0x05, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          ResourcePackRequest.class, ResourcePackRequest::new, map(0x06, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          ActiveFeatures.class, ActiveFeatures::new, map(0x07, MINECRAFT_1_20_2, false));
+      clientbound.register(TagsUpdate.class, TagsUpdate::new, map(0x08, MINECRAFT_1_20_2, false));
     }
   },
   PLAY {
@@ -137,8 +174,11 @@ public enum StateRegistry {
           map(0x08, MINECRAFT_1_19, false),
           map(0x09, MINECRAFT_1_19_1, false),
           map(0x08, MINECRAFT_1_19_3, false),
-          map(0x09, MINECRAFT_1_19_4, false));
+          map(0x09, MINECRAFT_1_19_4, false),
-      serverbound.register(LegacyChat.class, LegacyChat::new,
+          map(0x0A, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          LegacyChat.class,
+          LegacyChat::new,
           map(0x01, MINECRAFT_1_7_2, false),
           map(0x02, MINECRAFT_1_9, false),
           map(0x03, MINECRAFT_1_12, false),
@@ -152,9 +192,13 @@ public enum StateRegistry {
           map(0x05, MINECRAFT_1_19_1, MINECRAFT_1_19_1, false));
       serverbound.register(SessionPlayerCommand.class, SessionPlayerCommand::new,
           map(0x04, MINECRAFT_1_19_3, false));
-      serverbound.register(SessionPlayerChat.class, SessionPlayerChat::new,
+      serverbound.register(
-          map(0x05, MINECRAFT_1_19_3, false));
+          SessionPlayerChat.class,
-      serverbound.register(ClientSettings.class, ClientSettings::new,
+          SessionPlayerChat::new,
+          map(0x05, MINECRAFT_1_19_3, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          ClientSettings.class,
+          ClientSettings::new,
           map(0x15, MINECRAFT_1_7_2, false),
           map(0x04, MINECRAFT_1_9, false),
           map(0x05, MINECRAFT_1_12, false),
@@ -163,8 +207,11 @@ public enum StateRegistry {
           map(0x07, MINECRAFT_1_19, false),
           map(0x08, MINECRAFT_1_19_1, false),
           map(0x07, MINECRAFT_1_19_3, false),
-          map(0x08, MINECRAFT_1_19_4, false));
+          map(0x08, MINECRAFT_1_19_4, false),
-      serverbound.register(PluginMessage.class, PluginMessage::new,
+          map(0x09, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          PluginMessage.class,
+          PluginMessage::new,
           map(0x17, MINECRAFT_1_7_2, false),
           map(0x09, MINECRAFT_1_9, false),
           map(0x0A, MINECRAFT_1_12, false),
@@ -175,8 +222,11 @@ public enum StateRegistry {
           map(0x0C, MINECRAFT_1_19, false),
           map(0x0D, MINECRAFT_1_19_1, false),
           map(0x0C, MINECRAFT_1_19_3, false),
-          map(0x0D, MINECRAFT_1_19_4, false));
+          map(0x0D, MINECRAFT_1_19_4, false),
-      serverbound.register(KeepAlive.class, KeepAlive::new,
+          map(0x0F, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          KeepAlive.class,
+          KeepAlive::new,
           map(0x00, MINECRAFT_1_7_2, false),
           map(0x0B, MINECRAFT_1_9, false),
           map(0x0C, MINECRAFT_1_12, false),
@@ -188,8 +238,11 @@ public enum StateRegistry {
           map(0x11, MINECRAFT_1_19, false),
           map(0x12, MINECRAFT_1_19_1, false),
           map(0x11, MINECRAFT_1_19_3, false),
-          map(0x12, MINECRAFT_1_19_4, false));
+          map(0x12, MINECRAFT_1_19_4, false),
-      serverbound.register(ResourcePackResponse.class, ResourcePackResponse::new,
+          map(0x14, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          ResourcePackResponse.class,
+          ResourcePackResponse::new,
           map(0x19, MINECRAFT_1_8, false),
           map(0x16, MINECRAFT_1_9, false),
           map(0x18, MINECRAFT_1_12, false),
@@ -198,16 +251,24 @@ public enum StateRegistry {
           map(0x20, MINECRAFT_1_16, false),
           map(0x21, MINECRAFT_1_16_2, false),
           map(0x23, MINECRAFT_1_19, false),
-          map(0x24, MINECRAFT_1_19_1, false));
+          map(0x24, MINECRAFT_1_19_1, false),
+          map(0x27, MINECRAFT_1_20_2, false));
+      serverbound.register(
+          FinishedUpdate.class, FinishedUpdate::new, map(0x0B, MINECRAFT_1_20_2, false));
 
-      clientbound.register(BossBar.class, BossBar::new,
+      clientbound.register(
+          BossBar.class,
+          BossBar::new,
           map(0x0C, MINECRAFT_1_9, false),
           map(0x0D, MINECRAFT_1_15, false),
           map(0x0C, MINECRAFT_1_16, false),
           map(0x0D, MINECRAFT_1_17, false),
           map(0x0A, MINECRAFT_1_19, false),
-          map(0x0B, MINECRAFT_1_19_4, false));
+          map(0x0B, MINECRAFT_1_19_4, false),
-      clientbound.register(LegacyChat.class, LegacyChat::new,
+          map(0x0A, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          LegacyChat.class,
+          LegacyChat::new,
           map(0x02, MINECRAFT_1_7_2, true),
           map(0x0F, MINECRAFT_1_9, true),
           map(0x0E, MINECRAFT_1_13, true),
@@ -224,8 +285,11 @@ public enum StateRegistry {
           map(0x11, MINECRAFT_1_17, false),
           map(0x0E, MINECRAFT_1_19, false),
           map(0x0D, MINECRAFT_1_19_3, false),
-          map(0x0F, MINECRAFT_1_19_4, false));
+          map(0x0F, MINECRAFT_1_19_4, false),
-      clientbound.register(AvailableCommands.class, AvailableCommands::new,
+          map(0x10, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          AvailableCommands.class,
+          AvailableCommands::new,
           map(0x11, MINECRAFT_1_13, false),
           map(0x12, MINECRAFT_1_15, false),
           map(0x11, MINECRAFT_1_16, false),
@@ -233,8 +297,11 @@ public enum StateRegistry {
           map(0x12, MINECRAFT_1_17, false),
           map(0x0F, MINECRAFT_1_19, false),
           map(0x0E, MINECRAFT_1_19_3, false),
-          map(0x10, MINECRAFT_1_19_4, false));
+          map(0x10, MINECRAFT_1_19_4, false),
-      clientbound.register(PluginMessage.class, PluginMessage::new,
+          map(0x11, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          PluginMessage.class,
+          PluginMessage::new,
           map(0x3F, MINECRAFT_1_7_2, false),
           map(0x18, MINECRAFT_1_9, false),
           map(0x19, MINECRAFT_1_13, false),
@@ -246,8 +313,11 @@ public enum StateRegistry {
           map(0x15, MINECRAFT_1_19, false),
           map(0x16, MINECRAFT_1_19_1, false),
           map(0x15, MINECRAFT_1_19_3, false),
-          map(0x17, MINECRAFT_1_19_4, false));
+          map(0x17, MINECRAFT_1_19_4, false),
-      clientbound.register(Disconnect.class, Disconnect::new,
+          map(0x18, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          Disconnect.class,
+          Disconnect::new,
           map(0x40, MINECRAFT_1_7_2, false),
           map(0x1A, MINECRAFT_1_9, false),
           map(0x1B, MINECRAFT_1_13, false),
@@ -259,8 +329,11 @@ public enum StateRegistry {
           map(0x17, MINECRAFT_1_19, false),
           map(0x19, MINECRAFT_1_19_1, false),
           map(0x17, MINECRAFT_1_19_3, false),
-          map(0x1A, MINECRAFT_1_19_4, false));
+          map(0x1A, MINECRAFT_1_19_4, false),
-      clientbound.register(KeepAlive.class, KeepAlive::new,
+          map(0x1B, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          KeepAlive.class,
+          KeepAlive::new,
           map(0x00, MINECRAFT_1_7_2, false),
           map(0x1F, MINECRAFT_1_9, false),
           map(0x21, MINECRAFT_1_13, false),
@@ -272,8 +345,11 @@ public enum StateRegistry {
           map(0x1E, MINECRAFT_1_19, false),
           map(0x20, MINECRAFT_1_19_1, false),
           map(0x1F, MINECRAFT_1_19_3, false),
-          map(0x23, MINECRAFT_1_19_4, false));
+          map(0x23, MINECRAFT_1_19_4, false),
-      clientbound.register(JoinGame.class, JoinGame::new,
+          map(0x24, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          JoinGame.class,
+          JoinGame::new,
           map(0x01, MINECRAFT_1_7_2, false),
           map(0x23, MINECRAFT_1_9, false),
           map(0x25, MINECRAFT_1_13, false),
@@ -285,8 +361,11 @@ public enum StateRegistry {
           map(0x23, MINECRAFT_1_19, false),
           map(0x25, MINECRAFT_1_19_1, false),
           map(0x24, MINECRAFT_1_19_3, false),
-          map(0x28, MINECRAFT_1_19_4, false));
+          map(0x28, MINECRAFT_1_19_4, false),
-      clientbound.register(Respawn.class, Respawn::new,
+          map(0x29, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          Respawn.class,
+          Respawn::new,
           map(0x07, MINECRAFT_1_7_2, true),
           map(0x33, MINECRAFT_1_9, true),
           map(0x34, MINECRAFT_1_12, true),
@@ -300,8 +379,11 @@ public enum StateRegistry {
           map(0x3B, MINECRAFT_1_19, true),
           map(0x3E, MINECRAFT_1_19_1, true),
           map(0x3D, MINECRAFT_1_19_3, true),
-          map(0x41, MINECRAFT_1_19_4, true));
+          map(0x41, MINECRAFT_1_19_4, true),
-      clientbound.register(ResourcePackRequest.class, ResourcePackRequest::new,
+          map(0x43, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          ResourcePackRequest.class,
+          ResourcePackRequest::new,
           map(0x48, MINECRAFT_1_8, false),
           map(0x32, MINECRAFT_1_9, false),
           map(0x33, MINECRAFT_1_12, false),
@@ -315,8 +397,11 @@ public enum StateRegistry {
           map(0x3A, MINECRAFT_1_19, false),
           map(0x3D, MINECRAFT_1_19_1, false),
           map(0x3C, MINECRAFT_1_19_3, false),
-          map(0x40, MINECRAFT_1_19_4, false));
+          map(0x40, MINECRAFT_1_19_4, false),
-      clientbound.register(HeaderAndFooter.class, HeaderAndFooter::new,
+          map(0x42, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          HeaderAndFooter.class,
+          HeaderAndFooter::new,
           map(0x47, MINECRAFT_1_8, true),
           map(0x48, MINECRAFT_1_9, true),
           map(0x47, MINECRAFT_1_9_4, true),
@@ -331,8 +416,11 @@ public enum StateRegistry {
           map(0x60, MINECRAFT_1_19, true),
           map(0x63, MINECRAFT_1_19_1, true),
           map(0x61, MINECRAFT_1_19_3, true),
-          map(0x65, MINECRAFT_1_19_4, true));
+          map(0x65, MINECRAFT_1_19_4, true),
-      clientbound.register(LegacyTitlePacket.class, LegacyTitlePacket::new,
+          map(0x68, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          LegacyTitlePacket.class,
+          LegacyTitlePacket::new,
           map(0x45, MINECRAFT_1_8, true),
           map(0x45, MINECRAFT_1_9, true),
           map(0x47, MINECRAFT_1_12, true),
@@ -346,31 +434,46 @@ public enum StateRegistry {
           map(0x58, MINECRAFT_1_18, true),
           map(0x5B, MINECRAFT_1_19_1, true),
           map(0x59, MINECRAFT_1_19_3, true),
-          map(0x5D, MINECRAFT_1_19_4, true));
+          map(0x5D, MINECRAFT_1_19_4, true),
-      clientbound.register(TitleTextPacket.class, TitleTextPacket::new,
+          map(0x5F, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          TitleTextPacket.class,
+          TitleTextPacket::new,
           map(0x59, MINECRAFT_1_17, true),
           map(0x5A, MINECRAFT_1_18, true),
           map(0x5D, MINECRAFT_1_19_1, true),
           map(0x5B, MINECRAFT_1_19_3, true),
-          map(0x5F, MINECRAFT_1_19_4, true));
+          map(0x5F, MINECRAFT_1_19_4, true),
-      clientbound.register(TitleActionbarPacket.class, TitleActionbarPacket::new,
+          map(0x61, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          TitleActionbarPacket.class,
+          TitleActionbarPacket::new,
           map(0x41, MINECRAFT_1_17, true),
           map(0x40, MINECRAFT_1_19, true),
           map(0x43, MINECRAFT_1_19_1, true),
           map(0x42, MINECRAFT_1_19_3, true),
-          map(0x46, MINECRAFT_1_19_4, true));
+          map(0x46, MINECRAFT_1_19_4, true),
-      clientbound.register(TitleTimesPacket.class, TitleTimesPacket::new,
+          map(0x48, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          TitleTimesPacket.class,
+          TitleTimesPacket::new,
           map(0x5A, MINECRAFT_1_17, true),
           map(0x5B, MINECRAFT_1_18, true),
           map(0x5E, MINECRAFT_1_19_1, true),
           map(0x5C, MINECRAFT_1_19_3, true),
-          map(0x60, MINECRAFT_1_19_4, true));
+          map(0x60, MINECRAFT_1_19_4, true),
-      clientbound.register(TitleClearPacket.class, TitleClearPacket::new,
+          map(0x62, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          TitleClearPacket.class,
+          TitleClearPacket::new,
           map(0x10, MINECRAFT_1_17, true),
           map(0x0D, MINECRAFT_1_19, true),
           map(0x0C, MINECRAFT_1_19_3, true),
-          map(0x0E, MINECRAFT_1_19_4, true));
+          map(0x0E, MINECRAFT_1_19_4, true),
-      clientbound.register(LegacyPlayerListItem.class, LegacyPlayerListItem::new,
+          map(0x0F, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          LegacyPlayerListItem.class,
+          LegacyPlayerListItem::new,
           map(0x38, MINECRAFT_1_7_2, false),
           map(0x2D, MINECRAFT_1_9, false),
           map(0x2E, MINECRAFT_1_12_1, false),
@@ -384,44 +487,59 @@ public enum StateRegistry {
           map(0x37, MINECRAFT_1_19_1, MINECRAFT_1_19_1, false));
       clientbound.register(RemovePlayerInfo.class, RemovePlayerInfo::new,
           map(0x35, MINECRAFT_1_19_3, false),
-          map(0x39, MINECRAFT_1_19_4, false));
+          map(0x39, MINECRAFT_1_19_4, false),
-      clientbound.register(UpsertPlayerInfo.class, UpsertPlayerInfo::new,
+          map(0x3B, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          UpsertPlayerInfo.class,
+          UpsertPlayerInfo::new,
           map(0x36, MINECRAFT_1_19_3, false),
-          map(0x3A, MINECRAFT_1_19_4, false));
+          map(0x3A, MINECRAFT_1_19_4, false),
-      clientbound.register(SystemChat.class, SystemChat::new,
+          map(0x3C, MINECRAFT_1_20_2, false));
+      clientbound.register(
+          SystemChat.class,
+          SystemChat::new,
           map(0x5F, MINECRAFT_1_19, true),
           map(0x62, MINECRAFT_1_19_1, true),
           map(0x60, MINECRAFT_1_19_3, true),
-          map(0x64, MINECRAFT_1_19_4, true));
+          map(0x64, MINECRAFT_1_19_4, true),
-      clientbound.register(PlayerChatCompletion.class, PlayerChatCompletion::new,
+          map(0x67, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          PlayerChatCompletion.class,
+          PlayerChatCompletion::new,
           map(0x15, MINECRAFT_1_19_1, true),
           map(0x14, MINECRAFT_1_19_3, true),
-          map(0x16, MINECRAFT_1_19_4, true));
+          map(0x16, MINECRAFT_1_19_4, true),
-      clientbound.register(ServerData.class, ServerData::new,
+          map(0x17, MINECRAFT_1_20_2, true));
+      clientbound.register(
+          ServerData.class,
+          ServerData::new,
           map(0x3F, MINECRAFT_1_19, false),
           map(0x42, MINECRAFT_1_19_1, false),
           map(0x41, MINECRAFT_1_19_3, false),
-          map(0x45, MINECRAFT_1_19_4, false));
+          map(0x45, MINECRAFT_1_19_4, false),
+          map(0x47, MINECRAFT_1_20_2, false));
+      clientbound.register(StartUpdate.class, StartUpdate::new, map(0x65, MINECRAFT_1_20_2, false));
     }
   },
   LOGIN {
     {
-      serverbound.register(ServerLogin.class, ServerLogin::new,
+      serverbound.register(ServerLogin.class, ServerLogin::new, map(0x00, MINECRAFT_1_7_2, false));
-          map(0x00, MINECRAFT_1_7_2, false));
+      serverbound.register(
-      serverbound.register(EncryptionResponse.class, EncryptionResponse::new,
+          EncryptionResponse.class, EncryptionResponse::new, map(0x01, MINECRAFT_1_7_2, false));
-          map(0x01, MINECRAFT_1_7_2, false));
+      serverbound.register(
-      serverbound.register(LoginPluginResponse.class, LoginPluginResponse::new,
+          LoginPluginResponse.class, LoginPluginResponse::new, map(0x02, MINECRAFT_1_13, false));
-          map(0x02, MINECRAFT_1_13, false));
+      serverbound.register(
-      clientbound.register(Disconnect.class, Disconnect::new,
+          LoginAcknowledged.class, LoginAcknowledged::new, map(0x03, MINECRAFT_1_20_2, false));
-          map(0x00, MINECRAFT_1_7_2, false));
+
-      clientbound.register(EncryptionRequest.class, EncryptionRequest::new,
+      clientbound.register(Disconnect.class, Disconnect::new, map(0x00, MINECRAFT_1_7_2, false));
-          map(0x01, MINECRAFT_1_7_2, false));
+      clientbound.register(
-      clientbound.register(ServerLoginSuccess.class, ServerLoginSuccess::new,
+          EncryptionRequest.class, EncryptionRequest::new, map(0x01, MINECRAFT_1_7_2, false));
-          map(0x02, MINECRAFT_1_7_2, false));
+      clientbound.register(
-      clientbound.register(SetCompression.class, SetCompression::new,
+          ServerLoginSuccess.class, ServerLoginSuccess::new, map(0x02, MINECRAFT_1_7_2, false));
-          map(0x03, MINECRAFT_1_8, false));
+      clientbound.register(
-      clientbound.register(LoginPluginMessage.class, LoginPluginMessage::new,
+          SetCompression.class, SetCompression::new, map(0x03, MINECRAFT_1_8, false));
-          map(0x04, MINECRAFT_1_13, false));
+      clientbound.register(
+          LoginPluginMessage.class, LoginPluginMessage::new, map(0x04, MINECRAFT_1_13, false));
     }
   };
 
@@ -435,9 +553,7 @@ public enum StateRegistry {
     return (direction == SERVERBOUND ? serverbound : clientbound).getProtocolRegistry(version);
   }
 
-  /**
+  /** Packet registry. */
-   * Packet registry.
-   */
   public static class PacketRegistry {
 
     private final Direction direction;
@@ -505,19 +621,24 @@ public enum StateRegistry {
           }
           ProtocolRegistry registry = this.versions.get(protocol);
           if (registry == null) {
-            throw new IllegalArgumentException("Unknown protocol version "
+            throw new IllegalArgumentException(
-                + current.protocolVersion);
+                "Unknown protocol version " + current.protocolVersion);
           }
 
           if (registry.packetIdToSupplier.containsKey(current.id)) {
-            throw new IllegalArgumentException("Can not register class " + clazz.getSimpleName()
+            throw new IllegalArgumentException(
-                + " with id " + current.id + " for " + registry.version
+                "Can not register class "
+                    + clazz.getSimpleName()
+                    + " with id "
+                    + current.id
+                    + " for "
+                    + registry.version
                     + " because another packet is already registered");
           }
 
           if (registry.packetClassToId.containsKey(clazz)) {
-            throw new IllegalArgumentException(clazz.getSimpleName()
+            throw new IllegalArgumentException(
-                + " is already registered for version " + registry.version);
+                clazz.getSimpleName() + " is already registered for version " + registry.version);
           }
 
           if (!current.encodeOnly) {
@@ -528,9 +649,7 @@ public enum StateRegistry {
       }
     }
 
-    /**
+    /** Protocol registry. */
-     * Protocol registry.
-     */
     public class ProtocolRegistry {
 
       public final ProtocolVersion version;
@@ -575,12 +694,20 @@ public enum StateRegistry {
         }
         return id;
       }
+
+      /**
+       * Checks if the registry contains a packet with the specified {@code id}.
+       *
+       * @param packet the packet to check
+       * @return {@code true} if the packet is registered, {@code false} otherwise
+       */
+      public boolean containsPacket(final MinecraftPacket packet) {
+        return this.packetClassToId.containsKey(packet.getClass());
+      }
     }
   }
 
-  /**
+  /** Packet mapping. */
-   * Packet mapping.
-   */
   public static final class PacketMapping {
 
     private final int id;
@@ -599,9 +726,12 @@ public enum StateRegistry {
     @Override
     public String toString() {
       return "PacketMapping{"
-          + "id=" + id
+          + "id="
-          + ", protocolVersion=" + protocolVersion
+          + id
-          + ", encodeOnly=" + encodeOnly
+          + ", protocolVersion="
+          + protocolVersion
+          + ", encodeOnly="
+          + encodeOnly
           + '}';
     }
 

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftEncoder.java

@@ -62,4 +62,8 @@ public class MinecraftEncoder extends MessageToByteEncoder<MinecraftPacket> {
     this.state = state;
     this.setProtocolVersion(registry.version);
   }
+
+  public ProtocolUtils.Direction getDirection() {
+    return direction;
+  }
 }

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/PlayPacketQueueHandler.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.netty;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.StateRegistry;
+import io.netty.channel.ChannelDuplexHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelPromise;
+import io.netty.util.ReferenceCountUtil;
+import io.netty.util.internal.PlatformDependent;
+import java.util.Queue;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Queues up any pending PLAY packets while the client is in the CONFIG state.
+ *
+ * <p>Much of the Velocity API (i.e. chat messages) utilize PLAY packets, however the client is
+ * incapable of receiving these packets during the CONFIG state. Certain events such as the
+ * ServerPreConnectEvent may be called during this time, and we need to ensure that any API that
+ * uses these packets will work as expected.
+ *
+ * <p>This handler will queue up any packets that are sent to the client during this time, and send
+ * them once the client has (re)entered the PLAY state.
+ */
+public class PlayPacketQueueHandler extends ChannelDuplexHandler {
+
+  private final StateRegistry.PacketRegistry.ProtocolRegistry registry;
+  private final Queue<MinecraftPacket> queue = PlatformDependent.newMpscQueue();
+
+  /**
+   * Provides registries for client & server bound packets.
+   *
+   * @param version the protocol version
+   */
+  public PlayPacketQueueHandler(ProtocolVersion version, ProtocolUtils.Direction direction) {
+    this.registry =
+        StateRegistry.CONFIG.getProtocolRegistry(direction, version);
+  }
+
+  @Override
+  public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
+      throws Exception {
+    if (!(msg instanceof MinecraftPacket)) {
+      ctx.write(msg, promise);
+      return;
+    }
+
+    // If the packet exists in the CONFIG state, we want to always
+    // ensure that it gets sent out to the client
+    if (this.registry.containsPacket(((MinecraftPacket) msg))) {
+      ctx.write(msg, promise);
+      return;
+    }
+
+    // Otherwise, queue the packet
+    this.queue.offer((MinecraftPacket) msg);
+  }
+
+  @Override
+  public void channelInactive(@NotNull ChannelHandlerContext ctx) throws Exception {
+    this.releaseQueue(ctx, false);
+
+    super.channelInactive(ctx);
+  }
+
+  @Override
+  public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
+    this.releaseQueue(ctx, ctx.channel().isActive());
+  }
+
+  private void releaseQueue(ChannelHandlerContext ctx, boolean active) {
+    if (this.queue.isEmpty()) {
+      return;
+    }
+
+    // Send out all the queued packets
+    MinecraftPacket packet;
+    while ((packet = this.queue.poll()) != null) {
+      if (active) {
+        ctx.write(packet, ctx.voidPromise());
+      } else {
+        ReferenceCountUtil.release(packet);
+      }
+    }
+
+    if (active) {
+      ctx.flush();
+    }
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ClientSettings.java

@@ -23,10 +23,10 @@ import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
 import java.util.Objects;
+
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class ClientSettings implements MinecraftPacket {
-
   private @Nullable String locale;
   private byte viewDistance;
   private int chatVisibility;
@@ -120,16 +120,10 @@ public class ClientSettings implements MinecraftPacket {
 
   @Override
   public String toString() {
-    return "ClientSettings{"
+    return "ClientSettings{" + "locale='" + locale + '\'' + ", viewDistance=" + viewDistance +
-        + "locale='" + locale + '\''
+        ", chatVisibility=" + chatVisibility + ", chatColors=" + chatColors + ", skinParts=" +
-        + ", viewDistance=" + viewDistance
+        skinParts + ", mainHand=" + mainHand + ", chatFilteringEnabled=" + chatFilteringEnabled +
-        + ", chatVisibility=" + chatVisibility
+        ", clientListingAllowed=" + clientListingAllowed + '}';
-        + ", chatColors=" + chatColors
-        + ", skinParts=" + skinParts
-        + ", mainHand=" + mainHand
-        + ", chatFilteringEnabled=" + chatFilteringEnabled
-        + ", clientListingAllowed=" + clientListingAllowed
-        + '}';
   }
 
   @Override

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/JoinGame.java

@@ -42,6 +42,7 @@ public class JoinGame implements MinecraftPacket {
   private int viewDistance; // 1.14+
   private boolean reducedDebugInfo;
   private boolean showRespawnScreen;
+  private boolean doLimitedCrafting; // 1.20.2+
   private ImmutableSet<String> levelNames; // 1.16+
   private CompoundBinaryTag registry; // 1.16+
   private DimensionInfo dimensionInfo; // 1.16+
@@ -143,6 +144,14 @@ public class JoinGame implements MinecraftPacket {
     this.isHardcore = isHardcore;
   }
 
+  public boolean getDoLimitedCrafting() {
+    return doLimitedCrafting;
+  }
+
+  public void setDoLimitedCrafting(boolean doLimitedCrafting) {
+    this.doLimitedCrafting = doLimitedCrafting;
+  }
+
   public CompoundBinaryTag getCurrentDimensionData() {
     return currentDimensionData;
   }
@@ -177,32 +186,24 @@ public class JoinGame implements MinecraftPacket {
 
   @Override
   public String toString() {
-    return "JoinGame{"
+    return "JoinGame{" + "entityId=" + entityId + ", gamemode=" + gamemode + ", dimension=" +
-        + "entityId=" + entityId
+        dimension + ", partialHashedSeed=" + partialHashedSeed + ", difficulty=" + difficulty +
-        + ", gamemode=" + gamemode
+        ", isHardcore=" + isHardcore + ", maxPlayers=" + maxPlayers + ", levelType='" + levelType +
-        + ", dimension=" + dimension
+        '\'' + ", viewDistance=" + viewDistance + ", reducedDebugInfo=" + reducedDebugInfo +
-        + ", partialHashedSeed=" + partialHashedSeed
+        ", showRespawnScreen=" + showRespawnScreen + ", doLimitedCrafting=" + doLimitedCrafting +
-        + ", difficulty=" + difficulty
+        ", levelNames=" + levelNames + ", registry='" + registry + '\'' + ", dimensionInfo='" +
-        + ", isHardcore=" + isHardcore
+        dimensionInfo + '\'' + ", currentDimensionData='" + currentDimensionData + '\'' +
-        + ", maxPlayers=" + maxPlayers
+        ", previousGamemode=" + previousGamemode + ", simulationDistance=" + simulationDistance +
-        + ", levelType='" + levelType + '\''
+        ", lastDeathPosition='" + lastDeathPosition + '\'' + ", portalCooldown=" + portalCooldown +
-        + ", viewDistance=" + viewDistance
+        '}';
-        + ", reducedDebugInfo=" + reducedDebugInfo
-        + ", showRespawnScreen=" + showRespawnScreen
-        + ", levelNames=" + levelNames
-        + ", registry='" + registry + '\''
-        + ", dimensionInfo='" + dimensionInfo + '\''
-        + ", currentDimensionData='" + currentDimensionData + '\''
-        + ", previousGamemode=" + previousGamemode
-        + ", simulationDistance=" + simulationDistance
-        + ", lastDeathPosition='" + lastDeathPosition + '\''
-        + ", portalCooldown=" + portalCooldown
-        + '}';
   }
 
   @Override
   public void decode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
-    if (version.compareTo(ProtocolVersion.MINECRAFT_1_16) >= 0) {
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_20_2) >= 0) {
+      // haha funny, they made 1.20.2 more complicated
+      this.decode1202Up(buf, version);
+    } else if (version.compareTo(ProtocolVersion.MINECRAFT_1_16) >= 0) {
       // Minecraft 1.16 and above have significantly more complicated logic for reading this packet,
       // so separate it out.
       this.decode116Up(buf, version);
@@ -295,9 +296,46 @@ public class JoinGame implements MinecraftPacket {
     }
   }
 
+  private void decode1202Up(ByteBuf buf, ProtocolVersion version) {
+    this.entityId = buf.readInt();
+    this.isHardcore = buf.readBoolean();
+
+    this.levelNames = ImmutableSet.copyOf(ProtocolUtils.readStringArray(buf));
+
+    this.maxPlayers = ProtocolUtils.readVarInt(buf);
+
+    this.viewDistance = ProtocolUtils.readVarInt(buf);
+    this.simulationDistance = ProtocolUtils.readVarInt(buf);
+
+    this.reducedDebugInfo = buf.readBoolean();
+    this.showRespawnScreen = buf.readBoolean();
+    this.doLimitedCrafting = buf.readBoolean();
+
+    String dimensionIdentifier = ProtocolUtils.readString(buf);
+    String levelName = ProtocolUtils.readString(buf);
+    this.partialHashedSeed = buf.readLong();
+
+    this.gamemode = buf.readByte();
+    this.previousGamemode = buf.readByte();
+
+    boolean isDebug = buf.readBoolean();
+    boolean isFlat = buf.readBoolean();
+    this.dimensionInfo = new DimensionInfo(dimensionIdentifier, levelName, isFlat, isDebug);
+
+    // optional death location
+    if (buf.readBoolean()) {
+      this.lastDeathPosition = Pair.of(ProtocolUtils.readString(buf), buf.readLong());
+    }
+
+    this.portalCooldown = ProtocolUtils.readVarInt(buf);
+  }
+
   @Override
   public void encode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
-    if (version.compareTo(ProtocolVersion.MINECRAFT_1_16) >= 0) {
+    if (version.compareTo(ProtocolVersion.MINECRAFT_1_20_2) >= 0) {
+      // haha funny, they made 1.20.2 more complicated
+      this.encode1202Up(buf, version);
+    } else if (version.compareTo(ProtocolVersion.MINECRAFT_1_16) >= 0) {
       // Minecraft 1.16 and above have significantly more complicated logic for reading this packet,
       // so separate it out.
       this.encode116Up(buf, version);
@@ -396,6 +434,43 @@ public class JoinGame implements MinecraftPacket {
     }
   }
 
+  private void encode1202Up(ByteBuf buf, ProtocolVersion version) {
+    buf.writeInt(entityId);
+    buf.writeBoolean(isHardcore);
+
+    ProtocolUtils.writeStringArray(buf, levelNames.toArray(String[]::new));
+
+    ProtocolUtils.writeVarInt(buf, maxPlayers);
+
+    ProtocolUtils.writeVarInt(buf, viewDistance);
+    ProtocolUtils.writeVarInt(buf, simulationDistance);
+
+    buf.writeBoolean(reducedDebugInfo);
+    buf.writeBoolean(showRespawnScreen);
+    buf.writeBoolean(doLimitedCrafting);
+
+    ProtocolUtils.writeString(buf, dimensionInfo.getRegistryIdentifier());
+    ProtocolUtils.writeString(buf, dimensionInfo.getLevelName());
+    buf.writeLong(partialHashedSeed);
+
+    buf.writeByte(gamemode);
+    buf.writeByte(previousGamemode);
+
+    buf.writeBoolean(dimensionInfo.isDebugType());
+    buf.writeBoolean(dimensionInfo.isFlat());
+
+    // optional death location
+    if (lastDeathPosition != null) {
+      buf.writeBoolean(true);
+      ProtocolUtils.writeString(buf, lastDeathPosition.key());
+      buf.writeLong(lastDeathPosition.value());
+    } else {
+      buf.writeBoolean(false);
+    }
+
+    ProtocolUtils.writeVarInt(buf, portalCooldown);
+  }
+
   @Override
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/LoginAcknowledged.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class LoginAcknowledged implements MinecraftPacket {
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+  }
+
+  @Override
+  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+                               ProtocolVersion version) {
+    return 0;
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/PingIdentify.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2018-2021 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class PingIdentify implements MinecraftPacket {
+
+  private int id;
+
+  @Override
+  public String toString() {
+    return "Ping{" + "id=" + id + '}';
+  }
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
+    id = buf.readInt();
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction, ProtocolVersion version) {
+    buf.writeInt(id);
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ResourcePackRequest.java

@@ -17,17 +17,23 @@
 
 package com.velocitypowered.proxy.protocol.packet;
 
+import com.google.common.base.Preconditions;
 import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.api.proxy.player.ResourcePackInfo;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
+import java.util.regex.Pattern;
+
 public class ResourcePackRequest implements MinecraftPacket {
 
   private @MonotonicNonNull String url;
@@ -35,6 +41,8 @@ public class ResourcePackRequest implements MinecraftPacket {
   private boolean isRequired; // 1.17+
   private @Nullable Component prompt; // 1.17+
 
+  private static final Pattern PLAUSIBLE_SHA1_HASH = Pattern.compile("^[a-z0-9]{40}$"); // 1.20.2+
+
   public @Nullable String getUrl() {
     return url;
   }
@@ -99,6 +107,19 @@ public class ResourcePackRequest implements MinecraftPacket {
     }
   }
 
+  public VelocityResourcePackInfo toServerPromptedPack() {
+    ResourcePackInfo.Builder builder =
+        new VelocityResourcePackInfo.BuilderImpl(Preconditions.checkNotNull(url)).setPrompt(prompt)
+            .setShouldForce(isRequired).setOrigin(ResourcePackInfo.Origin.DOWNSTREAM_SERVER);
+
+    if (hash != null && !hash.isEmpty()) {
+      if (PLAUSIBLE_SHA1_HASH.matcher(hash).matches()) {
+        builder.setHash(ByteBufUtil.decodeHexDump(hash));
+      }
+    }
+    return (VelocityResourcePackInfo) builder.build();
+  }
+
   @Override
   public boolean handle(MinecraftSessionHandler handler) {
     return handler.handle(this);
@@ -106,11 +127,7 @@ public class ResourcePackRequest implements MinecraftPacket {
 
   @Override
   public String toString() {
-    return "ResourcePackRequest{"
+    return "ResourcePackRequest{" + "url='" + url + '\'' + ", hash='" + hash + '\'' +
-        + "url='" + url + '\''
+        ", isRequired=" + isRequired + ", prompt='" + prompt + '\'' + '}';
-        + ", hash='" + hash + '\''
-        + ", isRequired=" + isRequired
-        + ", prompt='" + prompt + '\''
-        + '}';
   }
 }

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ResourcePackResponse.java

@@ -73,9 +73,6 @@ public class ResourcePackResponse implements MinecraftPacket {
 
   @Override
   public String toString() {
-    return "ResourcePackResponse{"
+    return "ResourcePackResponse{" + "hash=" + hash + ", " + "status=" + status + '}';
-        + "hash=" + hash + ", "
-        + "status=" + status
-        + '}';
   }
 }

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/ServerLogin.java

@@ -74,10 +74,7 @@ public class ServerLogin implements MinecraftPacket {
 
   @Override
   public String toString() {
-    return "ServerLogin{"
+    return "ServerLogin{" + "username='" + username + '\'' + "playerKey='" + playerKey + '\'' + '}';
-        + "username='" + username + '\''
-        + "playerKey='" + playerKey + '\''
-        + '}';
   }
 
   @Override
@@ -98,6 +95,11 @@ public class ServerLogin implements MinecraftPacket {
         }
       }
 
+      if (version.compareTo(ProtocolVersion.MINECRAFT_1_20_2) >= 0) {
+        this.holderUuid = ProtocolUtils.readUuid(buf);
+        return;
+      }
+
       if (version.compareTo(ProtocolVersion.MINECRAFT_1_19_1) >= 0) {
         if (buf.readBoolean()) {
           holderUuid = ProtocolUtils.readUuid(buf);
@@ -125,6 +127,11 @@ public class ServerLogin implements MinecraftPacket {
         }
       }
 
+      if (version.compareTo(ProtocolVersion.MINECRAFT_1_20_2) >= 0) {
+        ProtocolUtils.writeUuid(buf, this.holderUuid);
+        return;
+      }
+
       if (version.compareTo(ProtocolVersion.MINECRAFT_1_19_1) >= 0) {
         if (playerKey != null && playerKey.getSignatureHolder() != null) {
           buf.writeBoolean(true);

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/ActiveFeatures.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet.config;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+import net.kyori.adventure.key.Key;
+
+public class ActiveFeatures implements MinecraftPacket {
+
+  private Key[] activeFeatures;
+
+  public ActiveFeatures(Key[] activeFeatures) {
+    this.activeFeatures = activeFeatures;
+  }
+
+  public ActiveFeatures() {
+    this.activeFeatures = new Key[0];
+  }
+
+  public void setActiveFeatures(Key[] activeFeatures) {
+    this.activeFeatures = activeFeatures;
+  }
+
+  public Key[] getActiveFeatures() {
+    return activeFeatures;
+  }
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+    activeFeatures = ProtocolUtils.readKeyArray(buf);
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+    ProtocolUtils.writeKeyArray(buf, activeFeatures);
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/FinishedUpdate.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet.config;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class FinishedUpdate implements MinecraftPacket {
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+  }
+
+  @Override
+  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+                               ProtocolVersion version) {
+    return 0;
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/RegistrySync.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet.config;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.util.DeferredByteBufHolder;
+import io.netty.buffer.ByteBuf;
+
+public class RegistrySync extends DeferredByteBufHolder implements MinecraftPacket {
+
+  public RegistrySync() {
+    super(null);
+  }
+
+  // NBT change in 1.20.2 makes it difficult to parse this packet.
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+    this.replace(buf.readRetainedSlice(buf.readableBytes()));
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+    buf.writeBytes(content());
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/StartUpdate.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet.config;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class StartUpdate implements MinecraftPacket {
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+  }
+
+  @Override
+  public int expectedMaxLength(ByteBuf buf, ProtocolUtils.Direction direction,
+                               ProtocolVersion version) {
+    return 0;
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/config/TagsUpdate.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2018-2023 Velocity Contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet.config;
+
+import com.google.common.collect.ImmutableMap;
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+import java.util.Map;
+
+public class TagsUpdate implements MinecraftPacket {
+
+  private Map<String, Map<String, int[]>> tags;
+
+  public TagsUpdate(Map<String, Map<String, int[]>> tags) {
+    this.tags = tags;
+  }
+
+  public TagsUpdate() {
+    this.tags = Map.of();
+  }
+
+  @Override
+  public void decode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+    ImmutableMap.Builder<String, Map<String, int[]>> builder = ImmutableMap.builder();
+    int size = ProtocolUtils.readVarInt(buf);
+    for (int i = 0; i < size; i++) {
+      String key = ProtocolUtils.readString(buf);
+
+      int innerSize = ProtocolUtils.readVarInt(buf);
+      ImmutableMap.Builder<String, int[]> innerBuilder = ImmutableMap.builder();
+      for (int j = 0; j < innerSize; j++) {
+        String innerKey = ProtocolUtils.readString(buf);
+        int[] innerValue = ProtocolUtils.readVarIntArray(buf);
+        innerBuilder.put(innerKey, innerValue);
+      }
+
+      builder.put(key, innerBuilder.build());
+    }
+    tags = builder.build();
+  }
+
+  @Override
+  public void encode(ByteBuf buf, ProtocolUtils.Direction direction,
+                     ProtocolVersion protocolVersion) {
+    ProtocolUtils.writeVarInt(buf, tags.size());
+    for (Map.Entry<String, Map<String, int[]>> entry : tags.entrySet()) {
+      ProtocolUtils.writeString(buf, entry.getKey());
+      // Oh, joy
+      ProtocolUtils.writeVarInt(buf, entry.getValue().size());
+      for (Map.Entry<String, int[]> innerEntry : entry.getValue().entrySet()) {
+        // Yea, object oriented programming be damned
+        ProtocolUtils.writeString(buf, innerEntry.getKey());
+        ProtocolUtils.writeVarIntArray(buf, innerEntry.getValue());
+      }
+    }
+  }
+
+  @Override
+  public boolean handle(MinecraftSessionHandler handler) {
+    return handler.handle(this);
+  }
+}

proxy/src/main/java/com/velocitypowered/proxy/server/PingSessionHandler.java

@@ -32,8 +32,8 @@ import java.io.IOException;
 import java.util.concurrent.CompletableFuture;
 
 /**
- * Session handler used to implement
+ * Session handler used to implement {@link VelocityRegisteredServer#ping(EventLoop,
- * {@link VelocityRegisteredServer#ping(EventLoop, ProtocolVersion)}.
+ * ProtocolVersion)}.
  */
 public class PingSessionHandler implements MinecraftSessionHandler {
 
@@ -60,6 +60,7 @@ public class PingSessionHandler implements MinecraftSessionHandler {
     handshake.setProtocolVersion(version);
     connection.delayedWrite(handshake);
 
+    connection.setActiveSessionHandler(StateRegistry.STATUS);
     connection.setState(StateRegistry.STATUS);
     connection.delayedWrite(StatusRequest.INSTANCE);
 

proxy/src/main/java/com/velocitypowered/proxy/server/VelocityRegisteredServer.java

@@ -37,6 +37,7 @@ import com.velocitypowered.proxy.connection.MinecraftConnection;
 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.StateRegistry;
 import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftEncoder;
 import com.velocitypowered.proxy.protocol.netty.MinecraftVarintFrameDecoder;
@@ -94,8 +95,8 @@ public class VelocityRegisteredServer implements RegisteredServer, ForwardingAud
   }
 
   /**
-   * Pings the specified server using the specified event {@code loop}, claiming to be
+   * Pings the specified server using the specified event {@code loop}, claiming to be {@code
-   * {@code version}.
+   * version}.
    *
    * @param loop    the event loop to use
    * @param pingOptions the options to apply to this ping
@@ -106,31 +107,26 @@ public class VelocityRegisteredServer implements RegisteredServer, ForwardingAud
       throw new IllegalStateException("No Velocity proxy instance available");
     }
     CompletableFuture<ServerPing> pingFuture = new CompletableFuture<>();
-    server.createBootstrap(loop)
+    server.createBootstrap(loop).handler(new ChannelInitializer<Channel>() {
-        .handler(new ChannelInitializer<Channel>() {
       @Override
       protected void initChannel(Channel ch) throws Exception {
-            ch.pipeline()
+        ch.pipeline().addLast(FRAME_DECODER, new MinecraftVarintFrameDecoder())
-                .addLast(FRAME_DECODER, new MinecraftVarintFrameDecoder())
+            .addLast(READ_TIMEOUT, new ReadTimeoutHandler(
-                .addLast(READ_TIMEOUT,
+                pingOptions.getTimeout() == 0
-                    new ReadTimeoutHandler(pingOptions.getTimeout() == 0
+                    ? server.getConfiguration().getReadTimeout()
-                            ? server.getConfiguration().getReadTimeout() : pingOptions.getTimeout(),
+                    : pingOptions.getTimeout(), TimeUnit.MILLISECONDS))
-                        TimeUnit.MILLISECONDS))
             .addLast(FRAME_ENCODER, MinecraftVarintLengthEncoder.INSTANCE)
-                .addLast(MINECRAFT_DECODER,
+            .addLast(MINECRAFT_DECODER, new MinecraftDecoder(ProtocolUtils.Direction.CLIENTBOUND))
-                    new MinecraftDecoder(ProtocolUtils.Direction.CLIENTBOUND))
+            .addLast(MINECRAFT_ENCODER, new MinecraftEncoder(ProtocolUtils.Direction.SERVERBOUND));
-                .addLast(MINECRAFT_ENCODER,
-                    new MinecraftEncoder(ProtocolUtils.Direction.SERVERBOUND));
 
         ch.pipeline().addLast(HANDLER, new MinecraftConnection(ch, server));
       }
-        })
+    }).connect(serverInfo.getAddress()).addListener((ChannelFutureListener) future -> {
-        .connect(serverInfo.getAddress())
-        .addListener((ChannelFutureListener) future -> {
       if (future.isSuccess()) {
         MinecraftConnection conn = future.channel().pipeline().get(MinecraftConnection.class);
-            conn.setSessionHandler(new PingSessionHandler(
+        conn.setActiveSessionHandler(StateRegistry.HANDSHAKE,
-                pingFuture, VelocityRegisteredServer.this, conn, pingOptions.getProtocolVersion()));
+            new PingSessionHandler(pingFuture, VelocityRegisteredServer.this, conn,
+                pingOptions.getProtocolVersion()));
       } else {
         pingFuture.completeExceptionally(future.cause());
       }