Added a way to handle packets easily. ProtocolSupport support fixed

api/src/main/java/org/geysermc/floodgate/api/packet/PacketHandler.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.api.packet;
+
+import io.netty.channel.ChannelHandlerContext;
+
+/**
+ * For advanced users only! You shouldn't play with this unless you know what you're doing.
+ */
+public interface PacketHandler {
+    /**
+     * Called when a registered packet has been seen.
+     *
+     * @param ctx         the channel handler context of the connection
+     * @param packet      the packet instance
+     * @param serverbound if the packet is serverbound
+     * @return the packet it should forward. Can be null or a different packet / instance
+     */
+    Object handle(ChannelHandlerContext ctx, Object packet, boolean serverbound);
+}

api/src/main/java/org/geysermc/floodgate/api/packet/PacketHandlers.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.api.packet;
+
+import io.netty.channel.ChannelHandlerContext;
+import org.geysermc.floodgate.api.util.TriFunction;
+
+public interface PacketHandlers {
+    /**
+     * Register a specific class for a specific consumer.
+     *
+     * @param handler     the packet handler instance
+     * @param packetClass the class to start listening for
+     * @param consumer    the consumer to call once the packet has been seen
+     */
+    void register(
+            PacketHandler handler,
+            Class<?> packetClass,
+            TriFunction<ChannelHandlerContext, Object, Boolean, Object> consumer);
+
+    /**
+     * Register a specific class for the given packet handler's {@link
+     * PacketHandler#handle(ChannelHandlerContext, Object, boolean)}.
+     *
+     * @param handler     the packet handler instance
+     * @param packetClass the class to start listening for
+     */
+    default void register(PacketHandler handler, Class<?> packetClass) {
+        register(handler, packetClass, handler::handle);
+    }
+
+    /**
+     * Register every packet for the given packet handler's {@link PacketHandler#handle(ChannelHandlerContext,
+     * Object, boolean)}
+     */
+    void registerAll(PacketHandler handler);
+
+    /**
+     * Unregisters all handlers registered under the given packet handler
+     *
+     * @param handler the packet handler instance
+     */
+    void deregister(PacketHandler handler);
+}

api/src/main/java/org/geysermc/floodgate/api/util/TriFunction.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.api.util;
+
+import java.util.Objects;
+import java.util.function.Function;
+
+/**
+ * Represents a function that accepts three arguments and produces a result. This is the three-arity
+ * specialization of {@link Function}.
+ *
+ * <p>This is a <a href="package-summary.html">functional interface</a>
+ * whose functional method is {@link #apply(Object, Object, Object)}.
+ *
+ * @param <T> the type of the first argument to the function
+ * @param <U> the type of the second argument to the function
+ * @param <V> the type of the third argument of the function
+ * @param <R> the type of the result of the function
+ * @see Function
+ * @since 1.8
+ */
+@FunctionalInterface
+public interface TriFunction<T, U, V, R> {
+    /**
+     * Performs this operation on the given arguments.
+     *
+     * @param t the first input argument
+     * @param u the second input argument
+     * @param v the third input argument
+     */
+    R apply(T t, U u, V v);
+
+    /**
+     * Returns a composed function that first applies this function to its input, and then applies
+     * the {@code after} function to the result. If evaluation of either function throws an
+     * exception, it is relayed to the caller of the composed function.
+     *
+     * @param <S>   the type of output of the {@code after} function, and of the composed function
+     * @param after the function to apply after this function is applied
+     * @return a composed function that first applies this function and then applies the {@code
+     * after} function
+     * @throws NullPointerException if after is null
+     */
+    default <S> TriFunction<T, U, V, S> andThen(Function<? super R, ? extends S> after) {
+        Objects.requireNonNull(after);
+        return (T t, U u, V v) -> after.apply(apply(t, u, v));
+    }
+}

bungee/src/main/java/org/geysermc/floodgate/module/BungeeAddonModule.java

@@ -30,6 +30,7 @@ import com.google.inject.Singleton;
 import com.google.inject.multibindings.ProvidesIntoSet;
 import org.geysermc.floodgate.addon.AddonManagerAddon;
 import org.geysermc.floodgate.addon.DebugAddon;
+import org.geysermc.floodgate.addon.PacketHandlerAddon;
 import org.geysermc.floodgate.addon.data.BungeeDataAddon;
 import org.geysermc.floodgate.api.inject.InjectorAddon;
 import org.geysermc.floodgate.register.AddonRegister;
@@ -57,4 +58,10 @@ public final class BungeeAddonModule extends AbstractModule {
     public InjectorAddon debugAddon() {
         return new DebugAddon();
     }
+
+    @Singleton
+    @ProvidesIntoSet
+    public InjectorAddon packetHandlerAddon() {
+        return new PacketHandlerAddon();
+    }
 }

common/src/main/java/org/geysermc/floodgate/addon/PacketHandlerAddon.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.addon;
+
+import com.google.inject.Inject;
+import com.google.inject.name.Named;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelPipeline;
+import org.geysermc.floodgate.addon.packethandler.ChannelInPacketHandler;
+import org.geysermc.floodgate.addon.packethandler.ChannelOutPacketHandler;
+import org.geysermc.floodgate.api.inject.InjectorAddon;
+import org.geysermc.floodgate.packet.PacketHandlersImpl;
+import org.geysermc.floodgate.util.Utils;
+
+public class PacketHandlerAddon implements InjectorAddon {
+    @Inject private PacketHandlersImpl packetHandlers;
+
+    @Inject
+    @Named("packetEncoder")
+    private String packetEncoder;
+
+    @Inject
+    @Named("packetDecoder")
+    private String packetDecoder;
+
+    @Override
+    public void onInject(Channel channel, boolean toServer) {
+        channel.pipeline().addAfter(
+                packetEncoder, "floodgate_phaddon_out",
+                new ChannelOutPacketHandler(packetHandlers, toServer)
+        ).addAfter(
+                packetDecoder, "floodgate_phaddon_in",
+                new ChannelInPacketHandler(packetHandlers, toServer)
+        );
+    }
+
+    @Override
+    public void onLoginDone(Channel channel) {
+
+    }
+
+    @Override
+    public void onRemoveInject(Channel channel) {
+        ChannelPipeline pipeline = channel.pipeline();
+
+        Utils.removeHandler(pipeline, "floodgate_phaddon_out");
+        Utils.removeHandler(pipeline, "floodgate_phaddon_in");
+    }
+
+    @Override
+    public boolean shouldInject() {
+        // this means that there has to be at least one PacketHandler registered to inject
+        return packetHandlers.hasHandlers();
+    }
+}

common/src/main/java/org/geysermc/floodgate/addon/packethandler/ChannelInPacketHandler.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.addon.packethandler;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.SimpleChannelInboundHandler;
+import org.geysermc.floodgate.api.util.TriFunction;
+import org.geysermc.floodgate.packet.PacketHandlersImpl;
+
+public class ChannelInPacketHandler extends SimpleChannelInboundHandler<Object> {
+    private final PacketHandlersImpl packetHandlers;
+    private final boolean toServer;
+
+    public ChannelInPacketHandler(PacketHandlersImpl packetHandlers, boolean toServer) {
+        this.packetHandlers = packetHandlers;
+        this.toServer = toServer;
+    }
+
+    @Override
+    protected void channelRead0(ChannelHandlerContext ctx, Object msg) {
+        Object packet = msg;
+        for (TriFunction<ChannelHandlerContext, Object, Boolean, Object> consumer :
+                packetHandlers.getPacketHandlers(msg.getClass())) {
+
+            Object res = consumer.apply(ctx, msg, toServer);
+            if (!res.equals(msg)) {
+                packet = res;
+            }
+        }
+
+        ctx.fireChannelRead(packet);
+    }
+}

common/src/main/java/org/geysermc/floodgate/addon/packethandler/ChannelOutPacketHandler.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.addon.packethandler;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToMessageEncoder;
+import java.util.List;
+import org.geysermc.floodgate.api.util.TriFunction;
+import org.geysermc.floodgate.packet.PacketHandlersImpl;
+
+public class ChannelOutPacketHandler extends MessageToMessageEncoder<Object> {
+    private final PacketHandlersImpl packetHandlers;
+    private final boolean toServer;
+
+    public ChannelOutPacketHandler(PacketHandlersImpl packetHandlers, boolean toServer) {
+        this.packetHandlers = packetHandlers;
+        this.toServer = toServer;
+    }
+
+    @Override
+    protected void encode(ChannelHandlerContext ctx, Object msg, List<Object> out) {
+        Object packet = msg;
+        for (TriFunction<ChannelHandlerContext, Object, Boolean, Object> consumer :
+                packetHandlers.getPacketHandlers(msg.getClass())) {
+
+            Object res = consumer.apply(ctx, msg, toServer);
+            if (!res.equals(msg)) {
+                packet = res;
+            }
+        }
+
+        out.add(packet);
+    }
+}

common/src/main/java/org/geysermc/floodgate/module/CommonModule.java

@@ -38,6 +38,7 @@ import org.geysermc.floodgate.api.SimpleFloodgateApi;
 import org.geysermc.floodgate.api.handshake.HandshakeHandlers;
 import org.geysermc.floodgate.api.inject.PlatformInjector;
 import org.geysermc.floodgate.api.logger.FloodgateLogger;
+import org.geysermc.floodgate.api.packet.PacketHandlers;
 import org.geysermc.floodgate.api.player.FloodgatePlayer;
 import org.geysermc.floodgate.config.FloodgateConfig;
 import org.geysermc.floodgate.config.FloodgateConfigHolder;
@@ -51,6 +52,7 @@ import org.geysermc.floodgate.crypto.Base64Topping;
 import org.geysermc.floodgate.crypto.FloodgateCipher;
 import org.geysermc.floodgate.crypto.KeyProducer;
 import org.geysermc.floodgate.inject.CommonPlatformInjector;
+import org.geysermc.floodgate.packet.PacketHandlersImpl;
 import org.geysermc.floodgate.player.FloodgateHandshakeHandler;
 import org.geysermc.floodgate.pluginmessage.PluginMessageManager;
 import org.geysermc.floodgate.skin.SkinApplier;
@@ -66,6 +68,9 @@ public class CommonModule extends AbstractModule {
         bind(FloodgateApi.class).to(SimpleFloodgateApi.class);
         bind(PlatformInjector.class).to(CommonPlatformInjector.class);
         bind(HandshakeHandlers.class).to(HandshakeHandlersImpl.class);
+
+        bind(PacketHandlers.class).to(PacketHandlersImpl.class);
+        bind(PacketHandlersImpl.class).asEagerSingleton();
     }
 
     @Provides

common/src/main/java/org/geysermc/floodgate/packet/PacketHandlersImpl.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2019-2021 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Floodgate
+ */
+
+package org.geysermc.floodgate.packet;
+
+import io.netty.channel.ChannelHandlerContext;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.geysermc.floodgate.api.packet.PacketHandler;
+import org.geysermc.floodgate.api.packet.PacketHandlers;
+import org.geysermc.floodgate.api.util.TriFunction;
+
+public final class PacketHandlersImpl implements PacketHandlers {
+    private final Map<PacketHandler, List<HandlerEntry>> handlers = new HashMap<>();
+    private final Set<TriFunction<ChannelHandlerContext, Object, Boolean, Object>> globalPacketHandlers = new HashSet<>();
+    private final Map<Class<?>, Set<TriFunction<ChannelHandlerContext, Object, Boolean, Object>>> packetHandlers = new HashMap<>();
+
+    @Override
+    public void register(
+            PacketHandler handler,
+            Class<?> packetClass,
+            TriFunction<ChannelHandlerContext, Object, Boolean, Object> consumer) {
+
+        if (handler == null || packetClass == null || consumer == null) {
+            return;
+        }
+
+        handlers.computeIfAbsent(handler, $ -> new ArrayList<>())
+                .add(new HandlerEntry(packetClass, consumer));
+
+        packetHandlers.computeIfAbsent(packetClass, $ -> new HashSet<>(globalPacketHandlers))
+                .add(consumer);
+    }
+
+    @Override
+    public void registerAll(PacketHandler handler) {
+        if (handler == null) {
+            return;
+        }
+
+        TriFunction<ChannelHandlerContext, Object, Boolean, Object> packetHandler = handler::handle;
+
+        handlers.computeIfAbsent(handler, $ -> new ArrayList<>())
+                .add(new HandlerEntry(null, packetHandler));
+
+        globalPacketHandlers.add(packetHandler);
+        for (Set<TriFunction<ChannelHandlerContext, Object, Boolean, Object>> handle : packetHandlers.values()) {
+            handle.add(packetHandler);
+        }
+    }
+
+    @Override
+    public void deregister(PacketHandler handler) {
+        if (handler == null) {
+            return;
+        }
+
+        List<HandlerEntry> values = handlers.remove(handler);
+        if (values != null) {
+            for (HandlerEntry value : values) {
+                Set<?> handlers = packetHandlers.get(value.getPacket());
+
+                if (handlers != null) {
+                    handlers.removeIf(o -> o.equals(value.getHandler()));
+                    if (handlers.isEmpty()) {
+                        packetHandlers.remove(value.getPacket());
+                    }
+                }
+
+                globalPacketHandlers.remove(value.getHandler());
+            }
+        }
+    }
+
+    public Collection<TriFunction<ChannelHandlerContext, Object, Boolean, Object>> getPacketHandlers(
+            Class<?> packet) {
+        return packetHandlers.getOrDefault(packet, Collections.emptySet());
+    }
+
+    public boolean hasHandlers() {
+        return !handlers.isEmpty();
+    }
+
+    @AllArgsConstructor
+    @Getter
+    private final static class HandlerEntry {
+        private final Class<?> packet;
+        private final TriFunction<ChannelHandlerContext, Object, Boolean, Object> handler;
+    }
+}

spigot/src/main/java/org/geysermc/floodgate/SpigotPlugin.java

@@ -28,7 +28,6 @@ package org.geysermc.floodgate;
 import com.google.inject.Guice;
 import com.google.inject.Injector;
 import org.bukkit.plugin.java.JavaPlugin;
-import org.geysermc.floodgate.api.InstanceHolder;
 import org.geysermc.floodgate.api.logger.FloodgateLogger;
 import org.geysermc.floodgate.module.PluginMessageModule;
 import org.geysermc.floodgate.module.ServerCommonModule;
@@ -42,6 +41,7 @@ import org.geysermc.floodgate.util.SpigotProtocolSupportListener;
 
 public final class SpigotPlugin extends JavaPlugin {
     private SpigotPlatform platform;
+    private Injector injector;
 
     @Override
     public void onLoad() {
@@ -49,7 +49,7 @@ public final class SpigotPlugin extends JavaPlugin {
         ReflectionUtils.setPrefix("net.minecraft.server." + minecraftVersion);
 
         long ctm = System.currentTimeMillis();
-        Injector injector = Guice.createInjector(
+        injector = Guice.createInjector(
                 new ServerCommonModule(getDataFolder().toPath()),
                 new SpigotPlatformModule(this)
         );
@@ -72,8 +72,7 @@ public final class SpigotPlugin extends JavaPlugin {
 
         // add ProtocolSupport support (hack)
         if (getServer().getPluginManager().getPlugin("ProtocolSupport") != null) {
-            InstanceHolder.getHandshakeHandlers()
-                    .addHandshakeHandler(new SpigotProtocolSupportHandler());
+            injector.getInstance(SpigotProtocolSupportHandler.class);
             SpigotProtocolSupportListener.registerHack(this);
         }
     }

spigot/src/main/java/org/geysermc/floodgate/module/SpigotAddonModule.java

@@ -30,6 +30,7 @@ import com.google.inject.Singleton;
 import com.google.inject.multibindings.ProvidesIntoSet;
 import org.geysermc.floodgate.addon.AddonManagerAddon;
 import org.geysermc.floodgate.addon.DebugAddon;
+import org.geysermc.floodgate.addon.PacketHandlerAddon;
 import org.geysermc.floodgate.addon.data.SpigotDataAddon;
 import org.geysermc.floodgate.api.inject.InjectorAddon;
 import org.geysermc.floodgate.register.AddonRegister;
@@ -57,4 +58,10 @@ public final class SpigotAddonModule extends AbstractModule {
     public InjectorAddon debugAddon() {
         return new DebugAddon();
     }
+
+    @Singleton
+    @ProvidesIntoSet
+    public InjectorAddon packetHandlerAddon() {
+        return new PacketHandlerAddon();
+    }
 }

spigot/src/main/java/org/geysermc/floodgate/util/SpigotProtocolSupportHandler.java

@@ -25,13 +25,18 @@
 
 package org.geysermc.floodgate.util;
 
+import com.google.inject.Inject;
+import com.google.inject.name.Named;
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.util.AttributeKey;
 import java.lang.reflect.Method;
 import java.util.UUID;
-import org.geysermc.floodgate.api.handshake.HandshakeData;
-import org.geysermc.floodgate.api.handshake.HandshakeHandler;
+import org.geysermc.floodgate.api.packet.PacketHandler;
+import org.geysermc.floodgate.api.packet.PacketHandlers;
+import org.geysermc.floodgate.api.player.FloodgatePlayer;
 
-public class SpigotProtocolSupportHandler implements HandshakeHandler {
+public class SpigotProtocolSupportHandler implements PacketHandler {
     private static final Method getFromChannel;
     private static final Method getLoginProfile;
 
@@ -51,7 +56,8 @@ public class SpigotProtocolSupportHandler implements HandshakeHandler {
         getFromChannel = ReflectionUtils.getMethod(connectionImpl, "getFromChannel", Channel.class);
         getLoginProfile = ReflectionUtils.getMethod(connectionImpl, "getLoginProfile");
 
-        Class<?> profile = ReflectionUtils.getClass("protocolsupport.protocol.utils.authlib.LoginProfile");
+        Class<?> profile =
+                ReflectionUtils.getClass("protocolsupport.protocol.utils.authlib.LoginProfile");
 
         setName = ReflectionUtils.getMethod(profile, "setName", String.class);
         setOriginalName = ReflectionUtils.getMethod(profile, "setOriginalName", String.class);
@@ -69,24 +75,38 @@ public class SpigotProtocolSupportHandler implements HandshakeHandler {
         Class<?> loginListener = ReflectionUtils.getClass(
                 "protocolsupport.protocol.packet.handler.AbstractLoginListener");
 
-        handleLoginStart = ReflectionUtils.getMethod(loginListener, "handleLoginStart", String.class);
+        handleLoginStart =
+                ReflectionUtils.getMethod(loginListener, "handleLoginStart", String.class);
+    }
+
+    @Inject
+    @Named("playerAttribute")
+    private AttributeKey<FloodgatePlayer> playerAttribute;
+
+    @Inject
+    public void register(PacketHandlers packetHandlers) {
+        packetHandlers.register(this, ReflectionUtils.getPrefixedClass("PacketLoginInStart"));
     }
 
     @Override
-    public void handle(HandshakeData data) {
-        if (data.isFloodgatePlayer() && !SpigotUtils.isBungeeData()) {
-            Object connection = ReflectionUtils.invoke(null, getFromChannel, data.getChannel());
-            Object profile = ReflectionUtils.invoke(connection, getLoginProfile);
-
-            // set correct uuid and name on ProtocolSupport's end, since we skip the LoginStart
-            ReflectionUtils.invoke(profile, setName, data.getCorrectUsername());
-            ReflectionUtils.invoke(profile, setOriginalName, data.getCorrectUsername());
-            ReflectionUtils.invoke(profile, setUuid, data.getCorrectUniqueId());
-            ReflectionUtils.invoke(profile, setOriginalUuid, data.getCorrectUniqueId());
-
-            Object temp = ReflectionUtils.invoke(connection, getNetworkManagerWrapper);
-            temp = ReflectionUtils.invoke(temp, getPacketListener);
-            ReflectionUtils.invoke(temp, handleLoginStart, data.getCorrectUsername());
+    public Object handle(ChannelHandlerContext ctx, Object packet, boolean serverbound) {
+        FloodgatePlayer player = ctx.channel().attr(playerAttribute).get();
+        if (player == null) {
+            return packet;
         }
+
+        Object connection = ReflectionUtils.invoke(null, getFromChannel, ctx.channel());
+        Object profile = ReflectionUtils.invoke(connection, getLoginProfile);
+
+        // set correct uuid and name on ProtocolSupport's end, since we skip the LoginStart
+        ReflectionUtils.invoke(profile, setName, player.getCorrectUsername());
+        ReflectionUtils.invoke(profile, setOriginalName, player.getCorrectUsername());
+        ReflectionUtils.invoke(profile, setUuid, player.getCorrectUniqueId());
+        ReflectionUtils.invoke(profile, setOriginalUuid, player.getCorrectUniqueId());
+
+        Object temp = ReflectionUtils.invoke(connection, getNetworkManagerWrapper);
+        temp = ReflectionUtils.invoke(temp, getPacketListener);
+        ReflectionUtils.invoke(temp, handleLoginStart, player.getCorrectUsername());
+        return packet;
     }
 }

spigot/src/main/resources/plugin.yml

@@ -4,6 +4,4 @@ version: ${project.version}
 author: ${project.organization.name}
 website: ${project.url}
 main: org.geysermc.floodgate.SpigotPlugin
-api-version: 1.13
-softdepend:
-  - ProtocolSupport
+api-version: 1.13

velocity/src/main/java/org/geysermc/floodgate/module/VelocityAddonModule.java

@@ -30,6 +30,7 @@ import com.google.inject.Singleton;
 import com.google.inject.multibindings.ProvidesIntoSet;
 import org.geysermc.floodgate.addon.AddonManagerAddon;
 import org.geysermc.floodgate.addon.DebugAddon;
+import org.geysermc.floodgate.addon.PacketHandlerAddon;
 import org.geysermc.floodgate.addon.data.VelocityDataAddon;
 import org.geysermc.floodgate.api.inject.InjectorAddon;
 import org.geysermc.floodgate.register.AddonRegister;
@@ -57,4 +58,10 @@ public final class VelocityAddonModule extends AbstractModule {
     public InjectorAddon debugAddon() {
         return new DebugAddon();
     }
+
+    @Singleton
+    @ProvidesIntoSet
+    public InjectorAddon packetHandlerAddon() {
+        return new PacketHandlerAddon();
+    }
 }