Developers can now change some Floodgate related data during handshake

api/src/main/java/org/geysermc/floodgate/api/InstanceHolder.java

@@ -27,6 +27,7 @@ package org.geysermc.floodgate.api;
 
 import java.util.UUID;
 import lombok.Getter;
+import org.geysermc.floodgate.api.handshake.HandshakeHandlers;
 import org.geysermc.floodgate.api.inject.PlatformInjector;
 import org.geysermc.floodgate.api.link.PlayerLink;
 
@@ -34,10 +35,16 @@ public final class InstanceHolder {
     @Getter private static FloodgateApi instance;
     @Getter private static PlayerLink playerLink;
     @Getter private static PlatformInjector injector;
+    @Getter private static HandshakeHandlers handshakeHandlers;
     private static UUID key;
 
-    public static boolean setInstance(FloodgateApi floodgateApi, PlayerLink link,
-                                      PlatformInjector platformInjector, UUID key) {
+    public static boolean setInstance(
+            FloodgateApi floodgateApi,
+            PlayerLink link,
+            PlatformInjector platformInjector,
+            HandshakeHandlers handshakeHandlers,
+            UUID key
+    ) {
         if (instance == null) {
             InstanceHolder.key = key;
         } else if (!InstanceHolder.key.equals(key)) {
@@ -46,6 +53,7 @@ public final class InstanceHolder {
         instance = floodgateApi;
         playerLink = link;
         injector = platformInjector;
+        InstanceHolder.handshakeHandlers = handshakeHandlers;
         return true;
     }
 

api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeData.java

@@ -0,0 +1,114 @@
+/*
+ * 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.handshake;
+
+import io.netty.channel.Channel;
+import org.geysermc.floodgate.util.BedrockData;
+import org.geysermc.floodgate.util.LinkedPlayer;
+import org.geysermc.floodgate.util.RawSkin;
+
+/**
+ * For advanced users only! You shouldn't play with this unless you know what you're doing.<br>
+ * <br>
+ * This class allows you change specific things of a Bedrock player before it is applied to the
+ * server. Note that at the time I'm writing this that the HandshakeData is created after requesting
+ * the player link. So the link is present here, if applicable.
+ */
+public interface HandshakeData {
+    /**
+     * Returns the Channel holding the connection between the client and the server.
+     */
+    Channel getChannel();
+
+    /**
+     * Returns true if the given player is a Floodgate player, false otherwise.
+     */
+    boolean isFloodgatePlayer();
+
+    /**
+     * Returns the decrypted BedrockData sent by Geyser or null if the player isn't a Floodgate
+     * player.
+     */
+    BedrockData getBedrockData();
+
+    /**
+     * Returns the linked account associated with the client or null if the player isn't linked or
+     * not a Floodgate player.
+     */
+    LinkedPlayer getLinkedPlayer();
+
+    /**
+     * Set the LinkedPlayer. This will be ignored if the player isn't a Floodgate player
+     *
+     * @param player the player to use as link
+     */
+    void setLinkedPlayer(LinkedPlayer player);
+
+    /**
+     * Returns the skin of the client. Can be null even though the player is a Floodgate player.
+     */
+    RawSkin getRawSkin();
+
+    /**
+     * Manually set the skin of the client.
+     *
+     * @param rawSkin the skin of the client
+     */
+    void setRawSkin(RawSkin rawSkin);
+
+    /**
+     * Returns the hostname used in the handshake packet. This is the hostname after Floodgate
+     * removed the data.
+     */
+    String getHostname();
+
+    /**
+     * Set the hostname of the handshake packet. Changing it here will also change it in the
+     * handshake packet.
+     *
+     * @param hostname the new hostname
+     */
+    void setHostname(String hostname);
+
+    /**
+     * Returns the reason to disconnect the current player.
+     */
+    String getDisconnectReason();
+
+    /**
+     * Set the reason to disconnect the current player.
+     *
+     * @param reason the reason to disconnect
+     */
+    void setDisconnectReason(String reason);
+
+    /**
+     * Returns if the player should be disconnected
+     */
+    default boolean shouldDisconnect() {
+        return getDisconnectReason() != null;
+    }
+}

api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandler.java

@@ -0,0 +1,45 @@
+/*
+ * 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.handshake;
+
+/**
+ * This class allows you to change and/or get specific data of the Bedrock client before Floodgate
+ * does something with this data. This means that Floodgate decrypts the data, then calls the
+ * handshake handlers and then applies the data to the connection.<br>
+ * <br>
+ * /!\ Note that this class will be called for both Java and Bedrock connections, but {@link
+ * HandshakeData#isFloodgatePlayer()} will be false and Floodgate related methods will return null
+ * for Java players
+ */
+@FunctionalInterface
+public interface HandshakeHandler {
+    /**
+     * Method that will be called during the time that Floodgate handles the handshake.
+     *
+     * @param data the data usable during the handshake
+     */
+    void handle(HandshakeData data);
+}

api/src/main/java/org/geysermc/floodgate/api/handshake/HandshakeHandlers.java

@@ -0,0 +1,51 @@
+/*
+ * 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.handshake;
+
+public interface HandshakeHandlers {
+    /**
+     * Register a custom handshake handler. This can be used to check and edit the player during the
+     * handshake handling.
+     *
+     * @param handshakeHandler the handshake handler to register
+     * @return a random (unique) int to identify this handshake handler or -1 if null
+     */
+    int addHandshakeHandler(HandshakeHandler handshakeHandler);
+
+    /**
+     * Removes a custom handshake handler by id.
+     *
+     * @param handshakeHandlerId the id of the handshake handler to remove
+     */
+    void removeHandshakeHandler(int handshakeHandlerId);
+
+    /**
+     * Remove a custom handshake handler by instance.
+     *
+     * @param handshakeHandler the instance to remove
+     */
+    void removeHandshakeHandler(Class<? extends HandshakeHandler> handshakeHandler);
+}

api/src/main/java/org/geysermc/floodgate/api/inject/PlatformInjector.java

@@ -73,7 +73,7 @@ public interface PlatformInjector {
      *
      * @param addon the class of the addon to remove from the addon list
      * @param <T>   the addon type
-     * @return the instance that was present when removing
+     * @return the removed addon instance
      */
     <T extends InjectorAddon> T removeAddon(Class<T> addon);
 }

api/src/main/java/org/geysermc/floodgate/api/logger/FloodgateLogger.java

@@ -89,4 +89,9 @@ public interface FloodgateLogger {
      * this method, but they will be hidden from the console.
      */
     void disableDebug();
+
+    /**
+     * Returns if debugging is enabled
+     */
+    boolean isDebug();
 }