Add Configuration State API (#1261)

* Implement Configuration State events

* Implement PlayerFinishedConfigurationEvent

* Fixed PlayerFinishConfigurationEvent execution

* Apply suggestions

* Fix keep alive when blocking PlayerFinishConfigurationEvent

* Add ServerConnection to configuration events

* Separate PlayPacketQueueHandler to fix AutoReadHolderHandler

---------

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

api/src/main/java/com/velocitypowered/api/event/player/configuration/PlayerEnterConfigurationEvent.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2024 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.event.player.configuration;
+
+import com.velocitypowered.api.network.ProtocolState;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.proxy.ServerConnection;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * This event is executed when a player with version 1.20.2 or higher enters the configuration phase.
+ * <p>From this moment on, until the {@link PlayerFinishedConfigurationEvent} is executed,
+ * the {@linkplain Player#getProtocolState()} method is guaranteed
+ * to return {@link ProtocolState#CONFIGURATION}.</p>
+ *
+ * @param player The player that has entered the configuration phase.
+ * @param server The server that will now (re-)configure the player.
+ * @since 3.3.0
+ * @sinceMinecraft 1.20.2
+ */
+public record PlayerEnterConfigurationEvent(@NotNull Player player, ServerConnection server) {
+}

api/src/main/java/com/velocitypowered/api/event/player/configuration/PlayerFinishConfigurationEvent.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2024 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.event.player.configuration;
+
+import com.velocitypowered.api.event.annotation.AwaitingEvent;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.proxy.ServerConnection;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * This event is executed when the player is about to finish the Configuration state.
+ * <p>Velocity will wait for this event to finish the configuration phase on the client.</p>
+ *
+ * @param player The player who is about to complete the configuration phase.
+ * @param server The server that is currently (re-)configuring the player.
+ * @since 3.3.0
+ * @sinceMinecraft 1.20.2
+ */
+@AwaitingEvent
+public record PlayerFinishConfigurationEvent(@NotNull Player player, @NotNull ServerConnection server) {
+}

api/src/main/java/com/velocitypowered/api/event/player/configuration/PlayerFinishedConfigurationEvent.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2024 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.event.player.configuration;
+
+import com.velocitypowered.api.network.ProtocolState;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.api.proxy.ServerConnection;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Event executed when a player of version 1.20.2 or higher finishes the Configuration state.
+ * <p>From this moment on, the {@link Player#getProtocolState()} method
+ * will return {@link ProtocolState#PLAY}.</p>
+ *
+ * @param player The player who has completed the Configuration state
+ * @param server The server that has (re-)configured the player.
+ * @since 3.3.0
+ * @sinceMinecraft 1.20.2
+ */
+public record PlayerFinishedConfigurationEvent(@NotNull Player player, @NotNull ServerConnection server) {
+}

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -45,7 +45,7 @@ import com.velocitypowered.proxy.command.builtin.ShutdownCommand;
 import com.velocitypowered.proxy.command.builtin.VelocityCommand;
 import com.velocitypowered.proxy.config.VelocityConfiguration;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
-import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.player.resourcepack.VelocityResourcePackInfo;
 import com.velocitypowered.proxy.connection.util.ServerListPingHandler;
 import com.velocitypowered.proxy.console.VelocityConsole;
 import com.velocitypowered.proxy.crypto.EncryptionUtils;

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

@@ -47,7 +47,8 @@ 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.protocol.netty.PlayPacketQueueInboundHandler;
+import com.velocitypowered.proxy.protocol.netty.PlayPacketQueueOutboundHandler;
 import com.velocitypowered.proxy.protocol.packet.SetCompressionPacket;
 import com.velocitypowered.proxy.util.except.QuietDecoderException;
 import io.netty.buffer.ByteBuf;
@@ -148,13 +149,11 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
         return;
       }
 
-      if (msg instanceof MinecraftPacket) {
+      if (msg instanceof MinecraftPacket pkt) {
-        MinecraftPacket pkt = (MinecraftPacket) msg;
         if (!pkt.handle(activeSessionHandler)) {
           activeSessionHandler.handleGeneric((MinecraftPacket) msg);
         }
-      } else if (msg instanceof HAProxyMessage) {
+      } else if (msg instanceof HAProxyMessage proxyMessage) {
-        HAProxyMessage proxyMessage = (HAProxyMessage) msg;
         this.remoteAddress = new InetSocketAddress(proxyMessage.sourceAddress(),
             proxyMessage.sourcePort());
       } else if (msg instanceof ByteBuf) {
@@ -383,9 +382,14 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     if (state == StateRegistry.CONFIG) {
       // Activate the play packet queue
       addPlayPacketQueueHandler();
-    } else if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE) != null) {
+    } else {
       // Remove the queue
-      this.channel.pipeline().remove(Connections.PLAY_PACKET_QUEUE);
+      if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE_OUTBOUND) != null) {
+        this.channel.pipeline().remove(Connections.PLAY_PACKET_QUEUE_OUTBOUND);
+      }
+      if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE_INBOUND) != null) {
+        this.channel.pipeline().remove(Connections.PLAY_PACKET_QUEUE_INBOUND);
+      }
     }
   }
 
@@ -393,10 +397,13 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
    * Adds the play packet queue handler.
    */
   public void addPlayPacketQueueHandler() {
-    if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE) == null) {
+    if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE_OUTBOUND) == null) {
-      this.channel.pipeline().addAfter(Connections.MINECRAFT_ENCODER, Connections.PLAY_PACKET_QUEUE,
+      this.channel.pipeline().addAfter(Connections.MINECRAFT_ENCODER, Connections.PLAY_PACKET_QUEUE_OUTBOUND,
-          new PlayPacketQueueHandler(this.protocolVersion,
+           new PlayPacketQueueOutboundHandler(this.protocolVersion, channel.pipeline().get(MinecraftEncoder.class).getDirection()));
-              channel.pipeline().get(MinecraftEncoder.class).getDirection()));
+    }
+    if (this.channel.pipeline().get(Connections.PLAY_PACKET_QUEUE_INBOUND) == null) {
+      this.channel.pipeline().addAfter(Connections.MINECRAFT_DECODER, Connections.PLAY_PACKET_QUEUE_INBOUND,
+           new PlayPacketQueueInboundHandler(this.protocolVersion, channel.pipeline().get(MinecraftDecoder.class).getDirection()));
     }
   }
 

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

@@ -40,8 +40,8 @@ import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.client.ClientPlaySessionHandler;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
-import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.player.resourcepack.VelocityResourcePackInfo;
-import com.velocitypowered.proxy.connection.player.resourcepack.ResourcePackHandler;
+import com.velocitypowered.proxy.connection.player.resourcepack.handler.ResourcePackHandler;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.StateRegistry;

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

@@ -37,7 +37,6 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import java.util.Optional;
 import java.util.StringJoiner;
-import net.kyori.adventure.identity.Identity;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.ComponentSerializer;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
@@ -143,7 +142,7 @@ public class BungeeCordMessageResponder {
         out.writeUTF("PlayerList");
         out.writeUTF(info.getServerInfo().getName());
 
-        StringJoiner joiner = new StringJoiner(", ");
+        final StringJoiner joiner = new StringJoiner(", ");
         for (Player online : info.getPlayersConnected()) {
           joiner.add(online.getUsername());
         }
@@ -187,10 +186,9 @@ public class BungeeCordMessageResponder {
 
     Component messageComponent = serializer.deserialize(message);
     if (target.equals("ALL")) {
-      proxy.sendMessage(Identity.nil(), messageComponent);
+      proxy.sendMessage(messageComponent);
     } else {
-      proxy.getPlayer(target).ifPresent(player -> player.sendMessage(Identity.nil(),
+      proxy.getPlayer(target).ifPresent(player -> player.sendMessage(messageComponent));
-          messageComponent));
     }
   }
 

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

@@ -29,7 +29,7 @@ import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
 import com.velocitypowered.proxy.connection.client.ClientConfigSessionHandler;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
-import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.player.resourcepack.VelocityResourcePackInfo;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
@@ -132,7 +132,8 @@ public class ConfigSessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(KeepAlivePacket packet) {
-    serverConn.ensureConnected().write(packet);
+    serverConn.getPendingPings().put(packet.getRandomId(), System.nanoTime());
+    serverConn.getPlayer().getConnection().write(packet);
     return true;
   }
 
@@ -193,30 +194,25 @@ public class ConfigSessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(FinishedUpdatePacket packet) {
-    MinecraftConnection smc = serverConn.ensureConnected();
+    final MinecraftConnection smc = serverConn.ensureConnected();
-    ConnectedPlayer player = serverConn.getPlayer();
+    final ConnectedPlayer player = serverConn.getPlayer();
-    ClientConfigSessionHandler configHandler =
+    final ClientConfigSessionHandler configHandler = (ClientConfigSessionHandler) player.getConnection().getActiveSessionHandler();
-        (ClientConfigSessionHandler) player.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) -> {
+    //noinspection DataFlowIssue
+    configHandler.handleBackendFinishUpdate(serverConn).thenRunAsync(() -> {
+      smc.write(FinishedUpdatePacket.INSTANCE);
       if (serverConn == player.getConnectedServer()) {
         smc.setActiveSessionHandler(StateRegistry.PLAY);
-        player.sendPlayerListHeaderAndFooter(
+        player.sendPlayerListHeaderAndFooter(player.getPlayerListHeader(), player.getPlayerListFooter());
-            player.getPlayerListHeader(), player.getPlayerListFooter());
         // The client cleared the tab list. TODO: Restore changes done via TabList API
         player.getTabList().clearAllSilent();
       } else {
-        smc.setActiveSessionHandler(StateRegistry.PLAY,
+        smc.setActiveSessionHandler(StateRegistry.PLAY, new TransitionSessionHandler(server, serverConn, resultFuture));
-            new TransitionSessionHandler(server, serverConn, resultFuture));
       }
-      if (player.resourcePackHandler().getFirstAppliedPack() == null
+      if (player.resourcePackHandler().getFirstAppliedPack() == null && resourcePackToApply != null) {
-              && resourcePackToApply != null) {
         player.resourcePackHandler().queueResourcePack(resourcePackToApply);
       }
-      smc.setAutoReading(true);
     }, smc.eventLoop());
     return true;
   }

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

@@ -166,12 +166,9 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
       if (player.getClientSettingsPacket() != null) {
         smc.write(player.getClientSettingsPacket());
       }
-      if (player.getConnection().getActiveSessionHandler() instanceof ClientPlaySessionHandler) {
+      if (player.getConnection().getActiveSessionHandler() instanceof ClientPlaySessionHandler clientPlaySessionHandler) {
         smc.setAutoReading(false);
-        ((ClientPlaySessionHandler) player.getConnection()
+        clientPlaySessionHandler.doSwitch().thenAcceptAsync((unused) -> smc.setAutoReading(true), smc.eventLoop());
-            .getActiveSessionHandler()).doSwitch().thenAcceptAsync((unused) -> {
-              smc.setAutoReading(true);
-            }, smc.eventLoop());
       }
     }
 

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

@@ -19,6 +19,8 @@ package com.velocitypowered.proxy.connection.client;
 
 import com.velocitypowered.api.event.player.CookieReceiveEvent;
 import com.velocitypowered.api.event.player.PlayerClientBrandEvent;
+import com.velocitypowered.api.event.player.configuration.PlayerFinishConfigurationEvent;
+import com.velocitypowered.api.event.player.configuration.PlayerFinishedConfigurationEvent;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
@@ -246,13 +248,11 @@ public class ClientConfigSessionHandler implements MinecraftSessionHandler {
       smc.write(brandPacket);
     }
 
-    player.getConnection().eventLoop().execute(() -> {
+    server.getEventManager().fire(new PlayerFinishConfigurationEvent(player, serverConn)).thenAcceptAsync(event -> {
       player.getConnection().write(FinishedUpdatePacket.INSTANCE);
       player.getConnection().getChannel().pipeline().get(MinecraftEncoder.class).setState(StateRegistry.PLAY);
-    });
+      server.getEventManager().fireAndForget(new PlayerFinishedConfigurationEvent(player, serverConn));
-
+    }, player.getConnection().eventLoop());
-    smc.write(FinishedUpdatePacket.INSTANCE);
-    smc.getChannel().pipeline().get(MinecraftEncoder.class).setState(StateRegistry.PLAY);
 
     return configSwitchFuture;
   }

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

@@ -27,6 +27,7 @@ import com.velocitypowered.api.event.player.CookieReceiveEvent;
 import com.velocitypowered.api.event.player.PlayerChannelRegisterEvent;
 import com.velocitypowered.api.event.player.PlayerClientBrandEvent;
 import com.velocitypowered.api.event.player.TabCompleteEvent;
+import com.velocitypowered.api.event.player.configuration.PlayerEnterConfigurationEvent;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
@@ -406,6 +407,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
     // Complete client switch
     player.getConnection().setActiveSessionHandler(StateRegistry.CONFIG);
     VelocityServerConnection serverConnection = player.getConnectedServer();
+    server.getEventManager().fireAndForget(new PlayerEnterConfigurationEvent(player, serverConnection));
     if (serverConnection != null) {
       MinecraftConnection smc = serverConnection.ensureConnected();
       CompletableFuture.runAsync(() -> {
@@ -512,7 +514,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
    * @return a future that completes when the switch is complete
    */
   public CompletableFuture<Void> doSwitch() {
-    VelocityServerConnection existingConnection = player.getConnectedServer();
+    final VelocityServerConnection existingConnection = player.getConnectedServer();
 
     if (existingConnection != null) {
       // Shut down the existing server connection.

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

@@ -37,6 +37,7 @@ import com.velocitypowered.api.event.player.KickedFromServerEvent.ServerKickResu
 import com.velocitypowered.api.event.player.PlayerModInfoEvent;
 import com.velocitypowered.api.event.player.PlayerSettingsChangedEvent;
 import com.velocitypowered.api.event.player.ServerPreConnectEvent;
+import com.velocitypowered.api.event.player.configuration.PlayerEnterConfigurationEvent;
 import com.velocitypowered.api.network.ProtocolState;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.permission.PermissionFunction;
@@ -59,8 +60,9 @@ import com.velocitypowered.proxy.adventure.VelocityBossBarImplementation;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftConnectionAssociation;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
-import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.player.bundle.BundleDelimiterHandler;
-import com.velocitypowered.proxy.connection.player.resourcepack.ResourcePackHandler;
+import com.velocitypowered.proxy.connection.player.resourcepack.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.player.resourcepack.handler.ResourcePackHandler;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults.Impl;
 import com.velocitypowered.proxy.connection.util.VelocityInboundConnection;
@@ -806,7 +808,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
             }, connection.eventLoop());
       } else if (event.getResult() instanceof final Notify res) {
         if (event.kickedDuringServerConnect() && previousConnection != null) {
-          sendMessage(Identity.nil(), res.getMessageComponent());
+          sendMessage(res.getMessageComponent());
         } else {
           disconnect(res.getMessageComponent());
         }
@@ -1227,8 +1229,9 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
               .get(MinecraftEncoder.class).setState(StateRegistry.CONFIG);
       // Make sure we don't send any play packets to the player after update start
       connection.addPlayPacketQueueHandler();
+      server.getEventManager().fireAndForget(new PlayerEnterConfigurationEvent(this, connectionInFlight));
     }, connection.eventLoop()).exceptionally((ex) -> {
-      logger.error("Error switching player connection to config state:", ex);
+      logger.error("Error switching player connection to config state", ex);
       return null;
     });
   }
@@ -1363,24 +1366,20 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
         }
 
         switch (status.getStatus()) {
-          case ALREADY_CONNECTED:
+          case ALREADY_CONNECTED -> sendMessage(ConnectionMessages.ALREADY_CONNECTED);
-            sendMessage(Identity.nil(), ConnectionMessages.ALREADY_CONNECTED);
+          case CONNECTION_IN_PROGRESS -> sendMessage(ConnectionMessages.IN_PROGRESS);
-            break;
+          case CONNECTION_CANCELLED -> {
-          case CONNECTION_IN_PROGRESS:
-            sendMessage(Identity.nil(), ConnectionMessages.IN_PROGRESS);
-            break;
-          case CONNECTION_CANCELLED:
             // Ignored; the plugin probably already handled this.
-            break;
+          }
-          case SERVER_DISCONNECTED:
+          case SERVER_DISCONNECTED -> {
-            Component reason = status.getReasonComponent()
+            final Component reason = status.getReasonComponent()
                     .orElse(ConnectionMessages.INTERNAL_SERVER_CONNECTION_ERROR);
             handleConnectionException(toConnect,
                     DisconnectPacket.create(reason, getProtocolVersion(), connection.getState()), status.isSafe());
-            break;
+          }
-          default:
+          default -> {
             // The only remaining value is successful (no need to do anything!)
-            break;
+          }
         }
       }, connection.eventLoop()).thenApply(Result::isSuccessful);
     }

proxy/src/main/java/com/velocitypowered/proxy/connection/player/bundle/BundleDelimiterHandler.java

@@ -15,10 +15,11 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package com.velocitypowered.proxy.connection.client;
+package com.velocitypowered.proxy.connection.player.bundle;
 
 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.StateRegistry;
 import com.velocitypowered.proxy.protocol.packet.BundleDelimiterPacket;
 import java.util.concurrent.CompletableFuture;

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/VelocityResourcePackInfo.java

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package com.velocitypowered.proxy.connection.player;
+package com.velocitypowered.proxy.connection.player.resourcepack;
 
 import com.google.common.base.Preconditions;
 import com.velocitypowered.api.proxy.player.ResourcePackInfo;

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/handler/Legacy117ResourcePackHandler.java

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package com.velocitypowered.proxy.connection.player.resourcepack;
+package com.velocitypowered.proxy.connection.player.resourcepack.handler;
 
 import com.velocitypowered.api.event.player.PlayerResourcePackStatusEvent;
 import com.velocitypowered.proxy.VelocityServer;

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/handler/LegacyResourcePackHandler.java

@@ -15,13 +15,14 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package com.velocitypowered.proxy.connection.player.resourcepack;
+package com.velocitypowered.proxy.connection.player.resourcepack.handler;
 
 import com.velocitypowered.api.event.player.PlayerResourcePackStatusEvent;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.player.ResourcePackInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.connection.player.resourcepack.ResourcePackResponseBundle;
 import java.util.ArrayDeque;
 import java.util.Arrays;
 import java.util.Collection;

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/handler/ModernResourcePackHandler.java

@@ -15,7 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package com.velocitypowered.proxy.connection.player.resourcepack;
+package com.velocitypowered.proxy.connection.player.resourcepack.handler;
 
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Multimaps;
@@ -23,6 +23,7 @@ import com.velocitypowered.api.event.player.PlayerResourcePackStatusEvent;
 import com.velocitypowered.api.proxy.player.ResourcePackInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
+import com.velocitypowered.proxy.connection.player.resourcepack.ResourcePackResponseBundle;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedList;

proxy/src/main/java/com/velocitypowered/proxy/connection/player/resourcepack/handler/ResourcePackHandler.java

@@ -15,14 +15,15 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-package com.velocitypowered.proxy.connection.player.resourcepack;
+package com.velocitypowered.proxy.connection.player.resourcepack.handler;
 
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.player.ResourcePackInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
-import com.velocitypowered.proxy.connection.player.VelocityResourcePackInfo;
+import com.velocitypowered.proxy.connection.player.resourcepack.ResourcePackResponseBundle;
+import com.velocitypowered.proxy.connection.player.resourcepack.VelocityResourcePackInfo;
 import com.velocitypowered.proxy.protocol.packet.ResourcePackRequestPacket;
 import com.velocitypowered.proxy.protocol.packet.ResourcePackResponsePacket;
 import com.velocitypowered.proxy.protocol.packet.chat.ComponentHolder;

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

@@ -35,7 +35,8 @@ 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";
+  public static final String PLAY_PACKET_QUEUE_OUTBOUND = "play-packet-queue-outbound";
+  public static final String PLAY_PACKET_QUEUE_INBOUND = "play-packet-queue-inbound";
 
   private Connections() {
     throw new AssertionError();

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

@@ -56,8 +56,7 @@ public class MinecraftDecoder extends ChannelInboundHandlerAdapter {
 
   @Override
   public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
-    if (msg instanceof ByteBuf) {
+    if (msg instanceof ByteBuf buf) {
-      ByteBuf buf = (ByteBuf) msg;
       tryDecode(ctx, buf);
     } else {
       ctx.fireChannelRead(msg);
@@ -147,4 +146,8 @@ public class MinecraftDecoder extends ChannelInboundHandlerAdapter {
     this.state = state;
     this.setProtocolVersion(registry.version);
   }
+
+  public ProtocolUtils.Direction getDirection() {
+    return direction;
+  }
 }

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

@@ -0,0 +1,94 @@
+/*
+ * 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.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 PlayPacketQueueInboundHandler extends ChannelDuplexHandler {
+
+  private final StateRegistry.PacketRegistry.ProtocolRegistry registry;
+  private final Queue<Object> queue = PlatformDependent.newMpscQueue();
+
+  /**
+   * Provides registries for client &amp; server bound packets.
+   *
+   * @param version the protocol version
+   */
+  public PlayPacketQueueInboundHandler(ProtocolVersion version, ProtocolUtils.Direction direction) {
+    this.registry = StateRegistry.CONFIG.getProtocolRegistry(direction, version);
+  }
+
+  @Override
+  public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+    if (msg instanceof final MinecraftPacket packet) {
+      // If the packet exists in the CONFIG state, we want to always
+      // ensure that it gets handled by the current handler
+      if (this.registry.containsPacket(packet)) {
+        ctx.fireChannelRead(msg);
+        return;
+      }
+    }
+
+    // Otherwise, queue the packet
+    this.queue.offer(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) {
+    // Handle all the queued packets
+    Object msg;
+    while ((msg = this.queue.poll()) != null) {
+      if (active) {
+        ctx.fireChannelRead(msg);
+      } else {
+        ReferenceCountUtil.release(msg);
+      }
+    }
+  }
+}

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

@@ -40,7 +40,7 @@ import org.jetbrains.annotations.NotNull;
  * <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 {
+public class PlayPacketQueueOutboundHandler extends ChannelDuplexHandler {
 
   private final StateRegistry.PacketRegistry.ProtocolRegistry registry;
   private final Queue<MinecraftPacket> queue = PlatformDependent.newMpscQueue();
@@ -50,28 +50,26 @@ public class PlayPacketQueueHandler extends ChannelDuplexHandler {
    *
    * @param version the protocol version
    */
-  public PlayPacketQueueHandler(ProtocolVersion version, ProtocolUtils.Direction direction) {
+  public PlayPacketQueueOutboundHandler(ProtocolVersion version, ProtocolUtils.Direction direction) {
-    this.registry =
+    this.registry = StateRegistry.CONFIG.getProtocolRegistry(direction, version);
-        StateRegistry.CONFIG.getProtocolRegistry(direction, version);
   }
 
   @Override
-  public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise)
+  public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
-      throws Exception {
+    if (!(msg instanceof final MinecraftPacket packet)) {
-    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))) {
+    if (this.registry.containsPacket(packet)) {
       ctx.write(msg, promise);
       return;
     }
 
     // Otherwise, queue the packet
-    this.queue.offer((MinecraftPacket) msg);
+    this.queue.offer(packet);
   }
 
   @Override
@@ -87,10 +85,6 @@ public class PlayPacketQueueHandler extends ChannelDuplexHandler {
   }
 
   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) {

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

@@ -21,7 +21,7 @@ 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.connection.player.resourcepack.VelocityResourcePackInfo;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import com.velocitypowered.proxy.protocol.ProtocolUtils.Direction;