Fixed ReplayMod, FML2, FML3, FORGE, Hostname detection

Signed-off-by: Lixfel <agga-games@gmx.de>

build.gradle

@@ -71,6 +71,15 @@ repositories {
     }
 }
 
+shadowJar {
+    exclude 'META-INF/*'
+    //https://imperceptiblethoughts.com/shadow/configuration/minimizing/
+    minimize {
+        exclude project(':')
+    }
+    duplicatesStrategy DuplicatesStrategy.INCLUDE
+}
+
 dependencies {
     compileOnly 'org.projectlombok:lombok:1.18.22'
     testCompileOnly 'org.projectlombok:lombok:1.18.22'

src/de/steamwar/bungeecore/BungeeCore.java

@@ -92,6 +92,7 @@ public class BungeeCore extends Plugin {
         });
         ProxyServer.getInstance().getScheduler().schedule(this, TabCompletionCache::invalidateOldEntries, 1, 1, TimeUnit.SECONDS);
 
+        new Hostname();
         new ServerListPing();
         new PluginMessage();
         new Schematica();
@@ -104,7 +105,7 @@ public class BungeeCore extends Plugin {
         new ChatListener();
         new BanListener();
         new CheckListener();
-        new SubserverProtocolFixer();
+        new IPSanitizer();
 
         local = new Node.LocalNode();
         if(MAIN_SERVER) {

src/de/steamwar/bungeecore/Node.java

@@ -22,7 +22,10 @@ package de.steamwar.bungeecore;
 import net.md_5.bungee.BungeeCord;
 import net.md_5.bungee.api.ProxyServer;
 
-import java.io.*;
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
 import java.nio.file.Files;
 import java.util.*;
 import java.util.concurrent.TimeUnit;
@@ -31,6 +34,7 @@ import java.util.logging.Level;
 
 public abstract class Node {
 
+    //-Xquickstart Langzeitperformance testen!
     private static final List<String> OPENJ9_ARGS = Arrays.asList(
             "-XX:+EnableCRIUSupport", "-XX:-CRIURestoreNonPortableMode",
             "-Xgc:excessiveGCratio=80", "-Xdisableexplicitgc", "-Xnoclassgc", "-Xmos128M", "-Xmns48M", "-XX:+ExitOnOutOfMemoryError", // initial heap half values of memory observed by 1.19 spectate server
@@ -118,6 +122,8 @@ public abstract class Node {
         cmd.add(worldDir);
         cmd.add("--level-name");
         cmd.add(levelName);
+        cmd.add("--plugins");
+        cmd.add("/home/lixfel/bpl");
         cmd.add("--port");
         cmd.add(String.valueOf(port));
         cmd.add("nogui");

src/de/steamwar/bungeecore/listeners/IPSanitizer.java

@@ -19,52 +19,41 @@
 
 package de.steamwar.bungeecore.listeners;
 
-import net.md_5.bungee.BungeeCord;
+import de.steamwar.bungeecore.BungeeCore;
 import net.md_5.bungee.api.event.LoginEvent;
 import net.md_5.bungee.connection.InitialHandler;
-import net.md_5.bungee.connection.LoginResult;
 import net.md_5.bungee.event.EventHandler;
-import net.md_5.bungee.protocol.Property;
+import net.md_5.bungee.netty.ChannelWrapper;
-import net.md_5.bungee.util.AddressUtil;
 
 import java.lang.reflect.Field;
 import java.net.InetSocketAddress;
 import java.util.logging.Level;
 
-public class SubserverProtocolFixer extends BasicListener {
+public class IPSanitizer extends BasicListener {
+
+    private static final Field initialHandlerCh;
+    static {
+        try {
+            initialHandlerCh = InitialHandler.class.getDeclaredField("ch");
+        } catch (NoSuchFieldException e) {
+            throw new SecurityException("Could not initialize Reflection", e);
+        }
+        initialHandlerCh.setAccessible(true);
+    }
+
+    public static ChannelWrapper getChannelWrapper(InitialHandler handler) {
+        try {
+            return (ChannelWrapper) initialHandlerCh.get(handler);
+        } catch (IllegalAccessException e) {
+            throw new SecurityException("Could not get channel wrapper", e);
+        }
+    }
 
     private final InetSocketAddress inetSocketAddress = new InetSocketAddress("127.127.127.127", 25565);
 
-    private Field field;
-
-    {
-        try {
-            field = InitialHandler.class.getDeclaredField("extraDataInHandshake");
-            field.setAccessible(true);
-        } catch (NoSuchFieldException e) {
-            BungeeCord.getInstance().getLogger().log(Level.SEVERE, e.getMessage(), e);
-        }
-    }
-
     @EventHandler
     public void loginEvent(LoginEvent e) {
-        InitialHandler initialHandler = ((InitialHandler) e.getConnection());
+        BungeeCore.get().getLogger().log(Level.INFO, e.getConnection().getSocketAddress() + " has logged in with user name " + e.getConnection().getName());
-
+        getChannelWrapper((InitialHandler) e.getConnection()).setRemoteAddress(inetSocketAddress);
-        String undashedUUID = initialHandler.getUniqueId().toString().replace("-", "");
-        String extraData = "\00" + AddressUtil.sanitizeAddress(inetSocketAddress) + "\00" + undashedUUID;
-
-        LoginResult result = initialHandler.getLoginProfile();
-        if (result != null) {
-            Property[] properties = result.getProperties();
-            if (properties.length > 0) {
-                extraData += "\00" + BungeeCord.getInstance().gson.toJson(properties);
-            }
-        }
-
-        try {
-            field.set(initialHandler, extraData);
-        } catch (IllegalAccessException ex) {
-            BungeeCord.getInstance().getLogger().log(Level.SEVERE, ex.getMessage(), ex);
-        }
     }
 }

src/de/steamwar/bungeecore/listeners/PluginMessage.java

@@ -28,24 +28,29 @@ import de.steamwar.messages.ChatSender;
 import de.steamwar.network.packets.NetworkPacket;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufAllocator;
+import io.netty.buffer.Unpooled;
 import net.md_5.bungee.api.ProxyServer;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
 import net.md_5.bungee.api.connection.Server;
 import net.md_5.bungee.api.event.PluginMessageEvent;
+import net.md_5.bungee.connection.InitialHandler;
 import net.md_5.bungee.event.EventHandler;
 import net.md_5.bungee.protocol.DefinedPacket;
 
 import java.net.InetSocketAddress;
-import java.util.Arrays;
+import java.util.*;
-import java.util.HashMap;
-import java.util.Map;
 import java.util.logging.Level;
 
 public class PluginMessage extends BasicListener {
 
     public static void send(ProxiedPlayer player, String legacyChannel, String channel, byte[] data) {
         // 1.12 format change
-        player.sendData(player.getPendingConnection().getVersion() > 340 ? channel : legacyChannel, data);
+        send(player, player.getPendingConnection().getVersion() > 340 ? channel : legacyChannel, data);
+    }
+
+    public static void send(ProxiedPlayer player, String channel, byte[] data) {
+        if(((InitialHandler)player.getPendingConnection()).getRegisteredChannels().contains(channel))
+            player.sendData(channel, data);
     }
 
     //TODO change to warning level
@@ -55,6 +60,8 @@ public class PluginMessage extends BasicListener {
 
     private final Lunar lunar = new Lunar();
 
+    private final Set<String> knownBrands = new HashSet<>();
+    private final Set<String> knownChannels = new HashSet<>();
     private final Map<String, Parser> handlers = new HashMap<>();
 
     public PluginMessage() {
@@ -63,8 +70,31 @@ public class PluginMessage extends BasicListener {
         FabricModSender fabricModSender = new FabricModSender();
         WorldDownloader wdl = new WorldDownloader();
 
-        register("REGISTER", false, directional(PASS_THROUGH, this::clientRegistersChannel));
+        knownBrands.add("vanilla");
-        register("minecraft:register", false, directional(PASS_THROUGH, this::clientRegistersChannel));
+        knownBrands.add("fabric");
+        knownBrands.add("forge"); //Forge registers all channels the server registers
+
+        knownChannels.add("fabric:container/open");
+        knownChannels.add("fabric:registry/sync/direct");
+        knownChannels.add("fabric-screen-handler-api-v1:open_screen");
+
+        knownChannels.add(FML.CHANNEL);
+        knownChannels.add("fml:loginwrapper");
+        knownChannels.add("fml:handshake");
+        knownChannels.add("fml:play");
+        knownChannels.add("forge:tier_sorting");
+        knownChannels.add("forge:split");
+        knownChannels.add("forge:login");
+        knownChannels.add("forge:handshake");
+
+        knownChannels.add("Replay|Restrict");
+        knownChannels.add("replaymod:restrict");
+        knownChannels.add("WDL|CONTROL");
+        knownChannels.add("wdl:control");
+        knownChannels.add("worldedit:cui");
+
+        register("REGISTER", false, directional(this::serverRegistersChannel, this::clientRegistersChannel));
+        register("minecraft:register", false, directional(this::serverRegistersChannel, this::clientRegistersChannel));
 
         register("BungeeCord", false, onlySWSource(PASS_THROUGH));
         register("bungeecord:main", false, onlySWSource(PASS_THROUGH));
@@ -73,6 +103,7 @@ public class PluginMessage extends BasicListener {
 
         register("sw:script_syntax", false, directional(onlySWSource(PASS_THROUGH), UNKNOWN));
         register("sw:bridge", false, directional(onlySWSource(async(event -> NetworkPacket.handle(new ServerMetaInfo(((Server) event.getSender()).getInfo()), event.getData()))), UNKNOWN));
+        register("worldedit:cui", false, PASS_THROUGH);
         register("fabricmodsender:mods", true, directional(UNKNOWN, fabricModSender::handlePluginMessage));
 
         register("WDL|REQUEST", false, DROP);
@@ -83,7 +114,7 @@ public class PluginMessage extends BasicListener {
         register(ApolloManager.PLUGIN_MESSAGE_CHANNEL, true, async(lunar::handlePluginMessage));
         register("LMC", true, directional(UNKNOWN, async(labyMod::handlePluginMessage)));
         register("labymod3:main", true, directional(UNKNOWN, async(labyMod::handlePluginMessage)));
-        register(FML.CHANNEL, true, directional(UNKNOWN, fml::handlePluginMessage));
+        register(FML.CHANNEL, true, directional(UNKNOWN, async(fml::handlePluginMessage)));
 
         //litematica/malilib https://github.com/maruohon/litematica/issues/75 https://github.com/maruohon/malilib/blob/liteloader_1.12.2/src/main/java/malilib/network/message/ConfigLockPacketHandler.java#L65
     }
@@ -114,7 +145,7 @@ public class PluginMessage extends BasicListener {
             if(channel.equals(ApolloManager.PLUGIN_MESSAGE_CHANNEL))
                 lunar.sendRestrictions(player);
 
-            if(!handlers.containsKey(channel))
+            if(!knownChannels.contains(channel))
                 //TODO change to warning level
                 BungeeCore.get().getLogger().log(Level.INFO, () -> player.getName() + " registered unknown channel " + channel);
         }
@@ -122,15 +153,22 @@ public class PluginMessage extends BasicListener {
         PASS_THROUGH.handle(event);
     }
 
+    private void serverRegistersChannel(PluginMessageEvent event) {
+        ProxiedPlayer player = (ProxiedPlayer)event.getReceiver();
+
+        List<String> channels = new ArrayList<>(Arrays.asList(new String(event.getData()).split("\0")));
+        channels.removeIf(channel -> channel.equals("sw:bridge"));
+        player.sendData((player).getPendingConnection().getVersion() > 340 ? "minecraft:register" : "REGISTER", String.join("\0", channels).getBytes());
+    }
+
     private void userBrand(PluginMessageEvent event) {
         ProxiedPlayer player = (ProxiedPlayer) event.getSender();
-        String brand = new String(event.getData());
+        ByteBuf buf = Unpooled.wrappedBuffer(event.getData());
+        String brand = DefinedPacket.readString(buf);
 
-        if(brand.equals("vanilla")) {
+        if(brand.startsWith("lunarclient:")) {
-            // nothing to do
-        } else if(brand.startsWith("lunarclient:")) {
             lunar.sendRestrictions(player);
-        } else {
+        } else if(!knownBrands.contains(brand)) {
             //TODO change to warning level
             BungeeCore.get().getLogger().log(Level.INFO, () -> player.getName() + " joined with unknown brand " + brand);
         }

src/de/steamwar/bungeecore/mods/FML.java

@@ -25,6 +25,7 @@ import de.steamwar.sql.Mod;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import net.md_5.bungee.api.ProxyServer;
+import net.md_5.bungee.api.connection.PendingConnection;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
 import net.md_5.bungee.api.event.PluginMessageEvent;
 import net.md_5.bungee.api.event.PostLoginEvent;
@@ -38,6 +39,10 @@ import java.util.concurrent.TimeUnit;
 public class FML extends BasicListener {
     // https://wiki.vg/Minecraft_Forge_Handshake#FML_protocol_.281.7_-_1.12.29
 
+    public static boolean isFML(PendingConnection connection, String type) {
+        return ((InitialHandler)connection).getExtraDataInHandshake().equals("\0" + type);
+    }
+
     public static final String CHANNEL = "FML|HS";
     private final byte[] helloPacket = new byte[]{
             /* Packet type: ServerHello */ 0,
@@ -58,9 +63,8 @@ public class FML extends BasicListener {
             }
         }
 
-        if(((InitialHandler)player.getPendingConnection()).getHandshake().getHost().endsWith("\0FML\0")) {
+        if(isFML(player.getPendingConnection(), "FML\0"))
             player.sendData(CHANNEL, helloPacket);
-        }
     }
 
     public void handlePluginMessage(PluginMessageEvent event) {

src/de/steamwar/bungeecore/mods/FML2.java

@@ -21,6 +21,7 @@ package de.steamwar.bungeecore.mods;
 
 import de.steamwar.bungeecore.BungeeCore;
 import de.steamwar.bungeecore.listeners.BasicListener;
+import de.steamwar.bungeecore.listeners.IPSanitizer;
 import de.steamwar.sql.Mod;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
@@ -29,67 +30,91 @@ import net.md_5.bungee.api.connection.PendingConnection;
 import net.md_5.bungee.api.event.LoginEvent;
 import net.md_5.bungee.connection.InitialHandler;
 import net.md_5.bungee.event.EventHandler;
-import net.md_5.bungee.netty.ChannelWrapper;
 import net.md_5.bungee.netty.HandlerBoss;
 import net.md_5.bungee.netty.PacketHandler;
 import net.md_5.bungee.protocol.DefinedPacket;
 import net.md_5.bungee.protocol.packet.LoginPayloadRequest;
 import net.md_5.bungee.protocol.packet.LoginPayloadResponse;
 
-import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 import java.util.logging.Level;
 
 public class FML2 extends BasicListener {
-    // https://wiki.vg/Minecraft_Forge_Handshake#FML2_protocol_.281.13_-_Current.29
+    // FML2: https://wiki.vg/Minecraft_Forge_Handshake#FML2_protocol_.281.13_-_Current.29
+    // FML3: https://github.com/adde0109/Ambassador/tree/non-api/src/main/java/org/adde0109/ambassador/forge
 
-    public static boolean isFML2(PendingConnection connection) {
+    // FORGE: https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/NetworkInitialization.java
-        return ((InitialHandler)connection).getHandshake().getHost().endsWith("\0FML2\0");
+    // FORGE: https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/ForgePacketHandler.java
-    }
+    // FORGE: https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/packets/ModVersions.java
 
-    private final Field initialHandlerCh;
+    private final byte[] fml2ModListPacket;
+    private final byte[] fml3ModListPacket;
+    private final byte[] forgeModListPacket;
 
     public FML2() {
-        try {
+        fml2ModListPacket = generateModListPacket(false);
-            initialHandlerCh = InitialHandler.class.getDeclaredField("ch");
+        fml3ModListPacket = generateModListPacket(true);
-        } catch (NoSuchFieldException e) {
-            throw new SecurityException("Could not initialize Reflection", e);
-        }
-        initialHandlerCh.setAccessible(true);
-    }
 
-    //TODO current identifier is \0FORGE and fmlNetworkVersion 0 ?
+        ByteBuf packet = Unpooled.buffer();
-    //TODO links for current implementation (if current checker not working)
+        packet.writeByte(1); // Mod list packet
-    //https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/ServerStatusPing.java
+        DefinedPacket.writeVarInt(0, packet); // Mod amount
-    //https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/NetworkContext.java#L26
+
-    //https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/tasks/ForgeNetworkConfigurationHandler.java#L20
+        ByteBuf wrapper = Unpooled.buffer();
-    //https://github.com/MinecraftForge/MinecraftForge/blob/1.20.x/src/main/java/net/minecraftforge/network/NetworkRegistry.java#L177
+        wrapper.writeByte(0); // Login wrapper packet
+        DefinedPacket.writeString("forge:handshake", wrapper);
+        DefinedPacket.writeVarInt(packet.readableBytes(), wrapper);
+        wrapper.writeBytes(packet);
+
+        forgeModListPacket = new byte[wrapper.readableBytes()];
+        wrapper.readBytes(forgeModListPacket);
+    }
 
     @EventHandler
     public void onLogin(LoginEvent event) {
         PendingConnection connection = event.getConnection();
 
-        if(!isFML2(connection))
+        boolean fml2 = FML.isFML(connection, "FML2\0");
+        boolean fml3 = FML.isFML(connection, "FML3\0");
+        boolean forge = FML.isFML(connection, "FORGE");
+        if(!fml2 && !fml3 && !forge)
             return;
 
-        try {
+        IPSanitizer.getChannelWrapper((InitialHandler) connection).getHandle().pipeline().get(HandlerBoss.class).setHandler(new FML2LoginHandler(event));
-            ((ChannelWrapper) initialHandlerCh.get(connection)).getHandle().pipeline().get(HandlerBoss.class).setHandler(new FML2LoginHandler(event));
-        } catch (IllegalAccessException e) {
-            BungeeCore.get().getLogger().log(Level.SEVERE, "Could not get Channel", e);
-            return;
-        }
 
         event.registerIntent(BungeeCore.get());
-        connection.unsafe().sendPacket(new LoginPayloadRequest(1, "fml:loginwrapper", new byte[] {
+        if(forge)
-                /* fml:handshake */ 13,102,109,108,58,104,97,110,100,115,104,97,107,101,
+            connection.unsafe().sendPacket(new LoginPayloadRequest(1, "forge:login", forgeModListPacket));
-                /* Packet length */ 4,
+        else
-                /* Type mod list */ 1,
+            connection.unsafe().sendPacket(new LoginPayloadRequest(1, "fml:loginwrapper", fml3 ? fml3ModListPacket : fml2ModListPacket));
-                /* Mod count */ 0,
+    }
-                /* Channel count */ 0,
+
-                /* Registry count */ 0
+    private byte[] generateModListPacket(boolean fml3) {
-        }));
+        ByteBuf packet = Unpooled.buffer();
+        packet.writeByte(1); // Mod list packet
+        DefinedPacket.writeVarInt(0, packet); // Mod amount
+
+        if(fml3) {
+            DefinedPacket.writeVarInt(1, packet); // Channel amount
+            DefinedPacket.writeString("forge:tier_sorting", packet);
+            DefinedPacket.writeString("1.0", packet);
+        } else {
+            DefinedPacket.writeVarInt(0, packet); // Channel amount
+        }
+
+        DefinedPacket.writeVarInt(0, packet); // Registries amount
+        if(fml3)
+            DefinedPacket.writeVarInt(0, packet); // DataPacks amount
+
+        ByteBuf wrapper = Unpooled.buffer();
+        DefinedPacket.writeString("fml:handshake", wrapper);
+        DefinedPacket.writeVarInt(packet.readableBytes(), wrapper);
+        wrapper.writeBytes(packet);
+
+        byte[] data = new byte[wrapper.readableBytes()];
+        wrapper.readBytes(data);
+        return data;
     }
 
     private static class FML2LoginHandler extends PacketHandler {
@@ -101,40 +126,51 @@ public class FML2 extends BasicListener {
 
         @Override
         public String toString() {
-            return "SteamWar FML2 Handler";
+            return "SteamWar Forge Handler";
         }
 
         @Override
         public void handle(LoginPayloadResponse response) {
+            boolean forge = FML.isFML(event.getConnection(), "FORGE");
             byte[] data = response.getData();
             if(data == null) {
-                abort(response, "Not FML2 client");
+                abort(response, "Not FML2/3 client");
                 return;
             }
 
             ByteBuf buf = Unpooled.wrappedBuffer(data);
-            if(!DefinedPacket.readString(buf).equals("fml:handshake")) {
+            if(forge && buf.readByte() != 0) {
-                abort(response, "Not FML2 handshake response");
+                abort(response, "Not FORGE login wrapper");
                 return;
             }
 
-            int packetLength = DefinedPacket.readVarInt(buf);
+            if(!DefinedPacket.readString(buf).equals(forge ? "forge:handshake" : "fml:handshake")) {
-            if(packetLength != buf.readableBytes()) {
+                abort(response, "Not FML2/3/FORGE handshake response");
-                abort(response, "FML2 packet size mismatch");
                 return;
             }
 
-            if(DefinedPacket.readVarInt(buf) != /* Mod List Reply */ 2) {
+            if(DefinedPacket.readVarInt(buf) != buf.readableBytes()) {
-                abort(response, "FML2 no mod list reply");
+                abort(response, "FML2/3/FORGE packet size mismatch");
+                return;
+            }
+
+            if(DefinedPacket.readVarInt(buf) != (forge ? /* Mod Versions */ 1 : /* Mod List Reply */ 2)) {
+                abort(response, "Not FML2/3/FORGE mod list reply");
                 return;
             }
 
             List<Mod> mods = new ArrayList<>();
 
             int modCount = DefinedPacket.readVarInt(buf);
-            for(int i = 0; i < modCount; i++)
+            for(int i = 0; i < modCount; i++) {
                 mods.add(Mod.getOrCreate(DefinedPacket.readString(buf), Mod.Platform.FORGE));
 
+                if(forge) {
+                    DefinedPacket.readString(buf); // Human readable name
+                    DefinedPacket.readString(buf); // Version
+                }
+            }
+
             if(!ModUtils.handleMods(event.getConnection().getUniqueId(), Locale.getDefault(), event::setReason, mods))
                 event.setCancelled(true);
 

src/de/steamwar/bungeecore/mods/Hostname.java

@@ -0,0 +1,58 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2024  SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bungeecore.mods;
+
+import de.steamwar.bungeecore.BungeeCore;
+import de.steamwar.bungeecore.listeners.BasicListener;
+import net.md_5.bungee.api.event.PlayerHandshakeEvent;
+import net.md_5.bungee.connection.InitialHandler;
+import net.md_5.bungee.event.EventHandler;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.logging.Level;
+
+public class Hostname extends BasicListener {
+
+    private final Set<String> knownHostnames = new HashSet<>();
+    private final Set<String> knownExtraData = new HashSet<>();
+
+    public Hostname() {
+        knownHostnames.add("steamwar.de");
+        knownHostnames.add("78.31.71.136");
+
+        knownExtraData.add("");
+        knownExtraData.add("\0FML\0");
+        knownExtraData.add("\0FML2\0");
+        knownExtraData.add("\0FML3\0");
+        knownExtraData.add("\0FORGE");
+    }
+
+    @EventHandler
+    public void onHandshake(PlayerHandshakeEvent event) {
+        String extraDataInHandshake = ((InitialHandler) event.getConnection()).getExtraDataInHandshake();
+        if (!knownHostnames.contains(event.getHandshake().getHost().toLowerCase())) {
+            BungeeCore.get().getLogger().log(Level.WARNING, () -> event.getConnection().getSocketAddress() + " connected with unknown hostname " + event.getHandshake() + " " + extraDataInHandshake);
+        } else if (!knownExtraData.contains(extraDataInHandshake)) {
+            BungeeCore.get().getLogger().log(Level.WARNING, () -> event.getConnection().getSocketAddress() + " connected with unknown extra data " + event.getHandshake() + " " + extraDataInHandshake);
+
+        }
+    }
+}

src/de/steamwar/bungeecore/mods/ReplayMod.java

@@ -20,9 +20,13 @@
 package de.steamwar.bungeecore.mods;
 
 import de.steamwar.bungeecore.Bauserver;
+import de.steamwar.bungeecore.Builderserver;
+import de.steamwar.bungeecore.BungeeCore;
 import de.steamwar.bungeecore.Subserver;
 import de.steamwar.bungeecore.listeners.BasicListener;
 import de.steamwar.bungeecore.listeners.PluginMessage;
+import net.md_5.bungee.api.ProxyServer;
+import net.md_5.bungee.api.config.ServerInfo;
 import net.md_5.bungee.api.connection.ProxiedPlayer;
 import net.md_5.bungee.api.event.ServerSwitchEvent;
 import net.md_5.bungee.event.EventHandler;
@@ -34,38 +38,36 @@ import java.util.Arrays;
 public class ReplayMod extends BasicListener {
     // https://gist.github.com/Johni0702/2547c463e51f65f312cb
     // https://github.com/ReplayMod/replay-restrictions/blob/master/bungeecord/src/main/java/de/johni0702/replay/restrictions/BungeeCordPlugin.java
+    // https://github.com/ReplayMod/ReplayMod/blob/stable/src/main/java/com/replaymod/core/utils/Restrictions.java
 
     private final byte[] restrict;
-    private final byte[] unlock;
 
     public ReplayMod() {
-        restrict = generatePacket(true);
-        unlock = generatePacket(false);
-    }
-
-    @EventHandler
-    public void onPlayerJoin(ServerSwitchEvent event) {
-        ProxiedPlayer player = event.getPlayer();
-        Subserver server = Subserver.getSubserver(player.getServer().getInfo());
-
-        PluginMessage.send(
-                player, "Replay|Restrict", "replaymod:restrict",
-                (server instanceof Bauserver && ((Bauserver) server).getOwner().equals(player.getUniqueId())) ? unlock : restrict
-        );
-    }
-
-    private byte[] generatePacket(boolean restrict) {
         ByteArrayOutputStream stream = new ByteArrayOutputStream();
         try {
             for(String restriction : Arrays.asList("no_xray", "no_noclip", "only_first_person", "only_recording_player")) {
                 byte[] bytes = restriction.getBytes();
                 stream.write(bytes.length);
                 stream.write(bytes);
-                stream.write(restrict ? 1 : 0);
+                stream.write(1); // restrict
             }
         } catch (IOException e) {
             throw new SecurityException(e);
         }
-        return stream.toByteArray();
+        restrict = stream.toByteArray();
+    }
+
+    @EventHandler
+    public void onPlayerJoin(ServerSwitchEvent event) {
+        ProxiedPlayer player = event.getPlayer();
+        ServerInfo server = player.getServer().getInfo();
+        if(ProxyServer.getInstance().getServerInfo(BungeeCore.LOBBY_SERVER) == server)
+            return;
+
+        Subserver subserver = Subserver.getSubserver(server);
+        if(subserver instanceof Builderserver || (subserver instanceof Bauserver && ((Bauserver) subserver).getOwner().equals(player.getUniqueId())))
+            return;
+
+        PluginMessage.send(player, "Replay|Restrict", "replaymod:restrict", restrict);
     }
 }

src/de/steamwar/bungeecore/mods/ServerListPing.java

@@ -21,31 +21,17 @@ package de.steamwar.bungeecore.mods;
 
 import com.google.gson.*;
 import de.steamwar.bungeecore.listeners.BasicListener;
-import lombok.AllArgsConstructor;
 import net.md_5.bungee.BungeeCord;
 import net.md_5.bungee.api.ServerPing;
-import net.md_5.bungee.api.connection.PendingConnection;
-import net.md_5.bungee.api.event.ProxyPingEvent;
-import net.md_5.bungee.event.EventHandler;
-import net.md_5.bungee.event.EventPriority;
-import net.md_5.bungee.protocol.ProtocolConstants;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Type;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
 
 public class ServerListPing extends BasicListener implements JsonSerializer<ServerPing>, JsonDeserializer<ServerPing> {
     // https://github.com/Aizistral-Studios/No-Chat-Reports/discussions/206
     // https://github.com/Aizistral-Studios/No-Chat-Reports/wiki/How-to-Get-Safe-Server-Status
-    // https://wiki.vg/Minecraft_Forge_Handshake#Changes_to_Server_List_Ping_2
 
     private final Gson gson;
-    private final Map<Integer, String> versionMap = new HashMap<>();
-    private final FML2Channel[] fml2Channels = new FML2Channel[]{new FML2Channel("minecraft:register"), new FML2Channel("minecraft:unregister"), new FML2Channel("fml:handshake")};
-
-    private final Map<ServerPing, PendingConnection> connections = new ConcurrentHashMap<>();
 
     public ServerListPing() {
         BungeeCord bungeeCord = BungeeCord.getInstance();
@@ -55,25 +41,11 @@ public class ServerListPing extends BasicListener implements JsonSerializer<Serv
             Field gsonField = BungeeCord.class.getDeclaredField("gson");
             gsonField.setAccessible(true);
             gsonField.set(bungeeCord, gson.newBuilder().registerTypeAdapter(ServerPing.class, this).create());
-
-            for(Field version : ProtocolConstants.class.getFields()) {
-                String name = version.getName();
-                if(version.getType() != int.class || !name.startsWith("MINECRAFT_"))
-                    continue;
-
-                versionMap.put(version.getInt(null), name.substring(10).replace('_', '.'));
-            }
         } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
             throw new SecurityException("Failed to inject ServerListPing", e);
         }
     }
 
-    @EventHandler(priority = EventPriority.HIGHEST)
-    public void onPing(ProxyPingEvent event) {
-        connections.put(event.getResponse(), event.getConnection());
-        connections.values().removeIf(connection -> !connection.isConnected()); // Prevent long term leaks
-    }
-
     @Override
     public JsonElement serialize(ServerPing ping, Type type, JsonSerializationContext context) {
         JsonElement element = gson.toJsonTree(ping, type);
@@ -81,14 +53,6 @@ public class ServerListPing extends BasicListener implements JsonSerializer<Serv
         JsonObject object = element.getAsJsonObject();
         object.addProperty("preventsChatReports", true);
 
-        PendingConnection connection = connections.remove(ping);
-        if(FML2.isFML2(connection)) {
-            object.add("forgeData", gson.toJsonTree(new FML2Data(fml2Channels, new FML2Mod[]{
-                    new FML2Mod("forge", "ANY"),
-                    new FML2Mod("minecraft", versionMap.get(connection.getVersion()))
-            }), FML2Data.class));
-        }
-
         return element;
     }
 
@@ -96,24 +60,4 @@ public class ServerListPing extends BasicListener implements JsonSerializer<Serv
     public ServerPing deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         return gson.fromJson(element, ServerPing.class);
     }
-
-    @AllArgsConstructor
-    private static class FML2Data {
-        private final int fmlNetworkVersion = 2;
-        private final FML2Channel[] channels;
-        private final FML2Mod[] mods;
-    }
-
-    @AllArgsConstructor
-    private static class FML2Channel {
-        private final String res;
-        private final String version = "FML2";
-        private final boolean required = true;
-    }
-
-    @AllArgsConstructor
-    private static class FML2Mod {
-        private final String modId;
-        private final String modmarker;
-    }
 }

src/de/steamwar/bungeecore/mods/WorldDownloader.java

@@ -28,6 +28,9 @@ import java.io.DataOutputStream;
 import java.io.IOException;
 
 public class WorldDownloader {
+    // https://wiki.vg/Plugin_channels/World_downloader
+    // https://github.com/Pokechu22/WorldDownloader-Serverside-Companion
+    // https://github.com/Pokechu22/WorldDownloader
 
     private final byte[] controlPacket;