TCPShield Fabric support (#40)

Adds Fabric support (huge, huge thanks to @Draylar)

.gitignore

@@ -1,4 +1,13 @@
+# Testing
+ip-whitelist/
+
+# IntelliJ
 .idea/
-*/target/
-*/*/target/
-*.iml
+build/
+*.iml
+
+# Gradle
+.gradle/
+gradle/
+gradlew
+gradlew.bat

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 TCPShield
+
+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.

README.md

@@ -6,12 +6,13 @@ It also parses passed IP addresses so the server is aware of the real player IP
 
 ### Compatibility
 
-TCPShield is compatible with Spigot / CraftBukkit, BungeeCord and Velocity.
+TCPShield is compatible with Spigot / CraftBukkit, BungeeCord, Velocity and Fabric.
 
 When using Spigot / CraftBukkit, [ProtocolLib](https://github.com/aadnk/ProtocolLib) needs to be installed.
+This does not apply when using Paper 1.16 build #503 or higher. 
 
 ### Setup
-Setting up the plugin is easy as cake. Please follow [these](https://docs.tcpshield.com/onboarding/tcpshield-plugin) guidelines. 
+Setting up the plugin is easy as pie. Please follow [these](https://docs.tcpshield.com/config/tcpshield-plugin) guidelines. 
 
 ### Compiling
 In order to compile TCPShield, [install Gradle](https://docs.gradle.org/current/userguide/installation.html) and run the following command in the project folder:
@@ -28,5 +29,6 @@ See [Contact](https://docs.tcpshield.com/about-us)
 
 These wonderful contributors have helped TCPShield make this plugin better! 
 
-* [Fuzzlemann](https://github.com/Fuzzlemann)
+* [Paul Zhang](https://github.com/paulzhng)
+* [Draylar](https://github.com/Draylar)
 * [RyanDeLap](https://github.com/RyanDeLap)

build.gradle

@@ -1,3 +1,4 @@
+import com.google.gson.GsonBuilder
 import com.google.gson.JsonObject
 import com.google.gson.JsonParser
 import org.yaml.snakeyaml.DumperOptions
@@ -18,6 +19,7 @@ buildscript {
 plugins {
     id 'java'
     id 'idea'
+    id 'fabric-loom' version '0.6-SNAPSHOT'
 }
 
 repositories {
@@ -39,6 +41,12 @@ repositories {
     maven {
         url = 'https://repo.velocitypowered.com/snapshots/'
     }
+    maven {
+        url = 'https://maven.fabricmc.net/'
+    }
+    flatDir {
+        dirs '/libs'
+    }
 }
 
 dependencies {
@@ -47,7 +55,7 @@ dependencies {
     compileOnly group: 'com.comphenix.protocol', name: 'ProtocolLib', version: '4.4.0'
 
     // Paper
-    compileOnly group: 'com.destroystokyo.paper', name: 'paper-api', version: '1.15.2-R0.1-SNAPSHOT'
+    compileOnly group: 'com.destroystokyo.paper', name: 'paper-api', version: '1.16.5-R0.1-20210227.144841-85'
 
     // BungeeCord
     compileOnly group: 'net.md-5', name: 'bungeecord-api', version: '1.14-SNAPSHOT'
@@ -55,9 +63,16 @@ dependencies {
     // Velocity
     compileOnly group: 'com.velocitypowered', name: 'velocity-api', version: '1.0.0-SNAPSHOT'
 
+    // Fabric
+    minecraft "com.mojang:minecraft:1.16.5"
+    mappings "net.fabricmc:yarn:1.16.5+build.5:v2"
+    modImplementation group: 'net.fabricmc', name: 'fabric-loader', version: '0.11.2'
+
     // Testing
-    testImplementation group: 'org.junit.jupiter', name:'junit-jupiter-api', version: '5.7.0-M1'
-    testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version:'5.7.0-M1'
+    testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: '5.7.0-M1'
+    testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: '5.7.0-M1'
+
+    compileOnly 'org.geyser:floodgate-spigot:2.0'
 }
 
 test {
@@ -68,7 +83,7 @@ configurations {
     testImplementation.extendsFrom compileOnly
 }
 
-version = '2.3'
+version = '2.5'
 group = 'net.tcpshield.tcpshield'
 archivesBaseName = 'TCPShield'
 
@@ -133,6 +148,7 @@ void updateYaml() {
 }
 
 void updateJson() {
+    def gson = new GsonBuilder().setPrettyPrinting().create();
     def velocityJson = new File('src/main/resources/velocity-plugin.json')
 
     def files = [velocityJson]
@@ -143,7 +159,7 @@ void updateJson() {
                 object.addProperty("version", version.toString())
 
                 new FileWriter(file).withCloseable { writer ->
-                    writer.write(object.toString())
+                    writer.write(gson.toJson(object))
                 }
             }
         }

settings.gradle

@@ -0,0 +1,10 @@
+pluginManagement {
+    repositories {
+        jcenter()
+        maven {
+            name = 'Fabric'
+            url = 'https://maven.fabricmc.net/'
+        }
+        gradlePluginPortal()
+    }
+}

src/main/java/net/tcpshield/tcpshield/Constants.java

@@ -1,7 +0,0 @@
-package net.tcpshield.tcpshield;
-
-public class Constants {
-
-    public static long MAX_TIME_DIFFERENCE = 3; // in seconds
-
-}

src/main/java/net/tcpshield/tcpshield/HandshakePacketHandler.java

@@ -3,24 +3,25 @@ package net.tcpshield.tcpshield;
 import net.tcpshield.tcpshield.abstraction.IPacket;
 import net.tcpshield.tcpshield.abstraction.IPlayer;
 import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
-import net.tcpshield.tcpshield.exception.*;
-import net.tcpshield.tcpshield.validation.TimestampValidation;
+import net.tcpshield.tcpshield.exception.IPModificationFailureException;
+import net.tcpshield.tcpshield.exception.InvalidIPException;
+import net.tcpshield.tcpshield.exception.TCPShieldInitializationException;
+import net.tcpshield.tcpshield.validation.IPValidation;
 
+import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.util.logging.Logger;
 
 public class HandshakePacketHandler {
 
     private final Logger logger;
-    private final SignatureVerifier signatureVerifier;
-    private final TimestampValidation timestampValidation;
+    private final IPValidation ipValidation;
     private final TCPShieldConfig config;
 
     public HandshakePacketHandler(Logger logger, TCPShieldConfig config) {
         try {
             this.logger = logger;
-            this.signatureVerifier = new SignatureVerifier();
-            this.timestampValidation = new TimestampValidation(config);
+            this.ipValidation = new IPValidation(config, logger);
             this.config = config;
         } catch (Exception e) {
             throw new TCPShieldInitializationException(e);
@@ -31,6 +32,12 @@ public class HandshakePacketHandler {
         String rawPayload = packet.getRawPayload();
 
         try {
+            InetAddress inetAddress = InetAddress.getByName(player.getIP());
+            if (!ipValidation.validateIP(inetAddress)) throw new InvalidIPException();
+
+            // raw payload is passed when it's not available -> e.g. Paper server list ping events
+            if (rawPayload == null) return;
+
             String extraData = null;
 
             // fix for e.g. incoming FML tagged packets
@@ -44,55 +51,34 @@ public class HandshakePacketHandler {
             }
 
             String[] payload = cleanedPayload.split("///", 4);
-            if (payload.length != 4)
-                throw new MalformedPayloadException("payload.length != 4. Raw payload = \"" + rawPayload + "\"");
+            if (payload.length < 2) return; // is nonetheless allowed as it passed the IP check
 
             String hostname = payload[0];
             String ipData = payload[1];
-            int timestamp;
-            try {
-                timestamp = Integer.parseInt(payload[2]);
-            } catch (NumberFormatException e) {
-                throw new MalformedPayloadException(e);
-            }
-            String signature = payload[3];
-
-            if (!timestampValidation.checkTimestamp(timestamp))
-                throw new InvalidTimestampException(timestamp, timestampValidation.getTime());
 
             String[] hostnameParts = ipData.split(":");
             String host = hostnameParts[0];
             int port = Integer.parseInt(hostnameParts[1]);
 
-            String reconstructedPayload = hostname + "///" + host + ":" + port + "///" + timestamp;
-
-            if (!signatureVerifier.verify(reconstructedPayload, signature))
-                throw new SigningVerificationFailureException();
-
             InetSocketAddress newIP = new InetSocketAddress(host, port);
             player.setIP(newIP);
 
             if (extraData != null) hostname = hostname + extraData;
 
             packet.modifyOriginalPacket(hostname);
-        } catch (InvalidTimestampException e) {
-            handleInvalidTimestamp(player, e.getTimestamp(), e.getCurrentTime());
-        } catch (SigningVerificationFailureException e) {
-            handleSigningVerificationFailure(player, rawPayload);
-        } catch (ConnectionNotProxiedException e) {
-            handleNotProxiedConnection(player, rawPayload);
+        } catch (InvalidIPException e) {
+            handleInvalidIPException(player, rawPayload);
         } catch (IPModificationFailureException e) {
-            this.logger.warning(String.format("%s[%s/%s]'s IP failed to be modified. Raw payload = \"%s\"", player.getName(), player.getUUID(), player.getIP(), rawPayload));
+            this.logger.warning(String.format("%s's IP failed to be modified. Raw payload = \"%s\"", player.getIP(), rawPayload));
             e.printStackTrace();
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 
-    private void handleInvalidTimestamp(IPlayer player, long timestamp, long currentTime) {
+    private void handleInvalidIPException(IPlayer player, String rawPayload) {
         if (config.isDebug()) {
-            this.logger.warning(String.format("%s[%s/%s] provided valid handshake information, but timestamp was not valid. " +
-                    "Provided timestamp: %d vs. system timestamp: %d. Please check your machine time. Timestamp validation mode: %s", player.getName(), player.getUUID(), player.getIP(), timestamp, currentTime, config.getTimestampValidationMode()));
+            this.logger.warning(String.format("%s was disconnected because the client failed the ip check and only-allowed-proxy-connections is enabled. Raw payload = \"%s\"", player.getIP(), rawPayload));
         }
 
         if (config.isOnlyProxy()) {
@@ -100,23 +86,8 @@ public class HandshakePacketHandler {
         }
     }
 
-    private void handleSigningVerificationFailure(IPlayer player, String rawPayload) {
-        if (config.isDebug()) {
-            this.logger.warning(String.format("%s[%s/%s] provided valid handshake information, but signing check failed. Raw payload = \"%s\"", player.getName(), player.getUUID(), player.getIP(), rawPayload));
-        }
-
-        if (config.isOnlyProxy()) {
-            player.disconnect();
-        }
+    public TCPShieldConfig getConfig() {
+        return config;
     }
 
-    private void handleNotProxiedConnection(IPlayer player, String rawPayload) {
-        if (!config.isOnlyProxy()) return;
-
-        if (config.isDebug()) {
-            this.logger.info(String.format("%s[%s/%s] was disconnected because no proxy info was received and only-allow-proxy-connections is enabled. Raw payload = \"%s\"", player.getName(), player.getUUID(), player.getIP(), rawPayload));
-        }
-
-        player.disconnect();
-    }
 }

src/main/java/net/tcpshield/tcpshield/ReflectionUtils.java

@@ -14,27 +14,7 @@ public class ReflectionUtils {
 
     private static final Table<Class<?>, String, Field> CACHED_FIELDS_BY_NAME = HashBasedTable.create();
     private static final Table<Class<?>, Class<?>, Field> CACHED_FIELDS_BY_CLASS = HashBasedTable.create();
-    private static final Field MODIFIERS_FIELD;
-
-    static {
-        Field tempModifiersField;
-        try {
-            tempModifiersField = getDeclaredField(Field.class, "modifiers");
-        } catch (NoSuchFieldException e) { // workaround for when searching for the modifiers field on Java 12 or higher
-            try {
-                Method getDeclaredFields0 = Class.class.getDeclaredMethod("getDeclaredFields0", boolean.class);
-                getDeclaredFields0.setAccessible(true);
-
-                Field[] fields = (Field[]) getDeclaredFields0.invoke(Field.class, false);
-                tempModifiersField = Arrays.stream(fields).filter(field -> field.getName().equals("modifiers")).findFirst().orElseThrow(() -> new TCPShieldInitializationException("Could not find the modifiers field"));
-            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e2) {
-                throw new TCPShieldInitializationException(e2);
-            }
-        }
-
-        MODIFIERS_FIELD = tempModifiersField;
-        MODIFIERS_FIELD.setAccessible(true);
-    }
+    private static Field modifiersField;
 
     public static void setFinalField(Object object, String fieldName, Object value) throws NoSuchFieldException, IllegalAccessException {
         setFinalField(object, getPrivateField(object.getClass(), fieldName), value);
@@ -43,7 +23,25 @@ public class ReflectionUtils {
     public static void setFinalField(Object object, Field field, Object value) throws IllegalAccessException {
         field.setAccessible(true);
         if (Modifier.isFinal(field.getModifiers())) {
-            MODIFIERS_FIELD.setInt(field, field.getModifiers() & ~Modifier.FINAL);
+            if (modifiersField == null) {
+                try {
+                    modifiersField = getDeclaredField(Field.class, "modifiers");
+                } catch (NoSuchFieldException e) { // workaround for when searching for the modifiers field on Java 12 or higher
+                    try {
+                        Method getDeclaredFields0 = Class.class.getDeclaredMethod("getDeclaredFields0", boolean.class);
+                        getDeclaredFields0.setAccessible(true);
+
+                        Field[] fields = (Field[]) getDeclaredFields0.invoke(Field.class, false);
+                        modifiersField = Arrays.stream(fields).filter(modifier -> modifier.getName().equals("modifiers")).findFirst().orElseThrow(() -> new TCPShieldInitializationException("Could not find the modifiers field"));
+                    } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e2) {
+                        throw new TCPShieldInitializationException(e2);
+                    }
+                }
+
+                modifiersField.setAccessible(true);
+            }
+
+             modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
         }
 
         setField(object, field, value);
@@ -73,16 +71,16 @@ public class ReflectionUtils {
         if (cachedField != null) return cachedField;
 
         Class<?> currentClass = clazz;
-        while (currentClass.getSuperclass() != null) {
-            for (Field field : clazz.getDeclaredFields()) {
-                if (field.getType() != searchFor) continue;
+        do {
+            for (Field field : currentClass.getDeclaredFields()) {
+                if (!searchFor.isAssignableFrom(field.getType())) continue;
 
                 CACHED_FIELDS_BY_CLASS.put(clazz, searchFor, field);
                 return field;
             }
 
-            currentClass = clazz.getSuperclass();
-        }
+            currentClass = currentClass.getSuperclass();
+        } while (currentClass != null);
 
         throw new IllegalArgumentException("no " + searchFor.getName() + " field for clazz = " + clazz.getName() + " found");
     }

src/main/java/net/tcpshield/tcpshield/SignatureVerifier.java

@@ -1,41 +0,0 @@
-package net.tcpshield.tcpshield;
-
-import com.google.common.io.ByteStreams;
-
-import java.io.IOException;
-import java.nio.charset.StandardCharsets;
-import java.security.*;
-import java.security.spec.InvalidKeySpecException;
-import java.security.spec.X509EncodedKeySpec;
-import java.util.Base64;
-
-public class SignatureVerifier {
-
-    private final PublicKey publicKey;
-
-    public SignatureVerifier() throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
-        byte[] encodedKey = ByteStreams.toByteArray(SignatureVerifier.class.getResourceAsStream("/signing_pub.key"));
-        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(encodedKey);
-
-        KeyFactory keyFactory = KeyFactory.getInstance("EC");
-        publicKey = keyFactory.generatePublic(keySpec);
-    }
-
-    public boolean verify(String str, String signature) {
-        return verify(str.getBytes(StandardCharsets.UTF_8), signature);
-    }
-
-    private boolean verify(byte[] data, String signature) {
-        try {
-            byte[] decodedSignature = Base64.getDecoder().decode(signature);
-
-            Signature sig = Signature.getInstance("SHA512withECDSA");
-            sig.initVerify(publicKey);
-            sig.update(data);
-
-            return sig.verify(decodedSignature);
-        } catch (IllegalArgumentException | SignatureException | NoSuchAlgorithmException | InvalidKeyException e) { // catching for illegal base64 encoding or invalid encoding for signatures
-            return false;
-        }
-    }
-}

src/main/java/net/tcpshield/tcpshield/abstraction/IPlayer.java

@@ -6,10 +6,6 @@ import java.net.InetSocketAddress;
 
 public interface IPlayer {
 
-    String getUUID();
-
-    String getName();
-
     String getIP();
 
     void setIP(InetSocketAddress ip) throws IPModificationFailureException;

src/main/java/net/tcpshield/tcpshield/abstraction/TCPShieldConfig.java

@@ -1,21 +1,28 @@
 package net.tcpshield.tcpshield.abstraction;
 
+import java.io.File;
+
 public abstract class TCPShieldConfig {
 
     protected boolean onlyProxy;
-    protected String timestampValidationMode;
+    protected File ipWhitelistFolder;
     protected boolean debug;
+    protected boolean geyser;
 
     public boolean isOnlyProxy() {
         return this.onlyProxy;
     }
 
-    public String getTimestampValidationMode() {
-        return this.timestampValidationMode;
+    public File getIPWhitelistFolder() {
+        return ipWhitelistFolder;
     }
 
     public boolean isDebug() {
         return this.debug;
     }
 
+    public boolean isGeyser() {
+        return this.geyser;
+    }
+
 }

src/main/java/net/tcpshield/tcpshield/bukkit/TCPShieldBukkit.java

@@ -13,8 +13,7 @@ public class TCPShieldBukkit extends JavaPlugin {
             new TCPShieldPaper(this).load();
         } else {
             if (Bukkit.getPluginManager().getPlugin("ProtocolLib") == null) {
-                //this.getLogger().warning("TCPShield not loading because ProtocolLib is not installed. Either use Paper to enable native compatibility or install ProtocolLib.");
-                this.getLogger().warning("TCPShield not loading because ProtocolLib is not installed. Please install ProtocolLib in order to use our plugin.");
+                this.getLogger().warning("TCPShield not loading because ProtocolLib is not installed. Either use Paper (1.16 build #503 or higher) to enable native compatibility or install ProtocolLib.");
                 return;
             }
 
@@ -22,13 +21,17 @@ public class TCPShieldBukkit extends JavaPlugin {
         }
     }
 
+    /**
+     * Checks if the server version supports native Paper support (Paper 1.16.5 build #503 or higher)
+     *
+     * @return if the server version supports native Paper support
+     */
     private boolean isPaper() {
-        if (true) return false; // disabled for now
-
         try {
-            Class.forName("com.destroystokyo.paper.event.player.PlayerHandshakeEvent");
+            Class<?> handshakeEvent = Class.forName("com.destroystokyo.paper.event.player.PlayerHandshakeEvent");
+            handshakeEvent.getMethod("getOriginalSocketAddressHostname");
             return true;
-        } catch (ClassNotFoundException e) {
+        } catch (ClassNotFoundException | NoSuchMethodException e) {
             return false;
         }
     }

src/main/java/net/tcpshield/tcpshield/bukkit/impl/BukkitConfigImpl.java

@@ -4,6 +4,8 @@ import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
 import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.plugin.java.JavaPlugin;
 
+import java.io.File;
+
 public class BukkitConfigImpl extends TCPShieldConfig {
 
     public BukkitConfigImpl(JavaPlugin javaPlugin) {
@@ -12,7 +14,8 @@ public class BukkitConfigImpl extends TCPShieldConfig {
         FileConfiguration config = javaPlugin.getConfig();
 
         this.onlyProxy = config.getBoolean("only-allow-proxy-connections");
-        this.timestampValidationMode = config.getString("timestamp-validation");
+        this.ipWhitelistFolder = new File(javaPlugin.getDataFolder(), "ip-whitelist");
+        this.geyser = config.getBoolean("enable-geyser-compatibility");
         this.debug = config.getBoolean("debug-mode");
     }
 }

src/main/java/net/tcpshield/tcpshield/bukkit/paper/PaperHandshakePacketHandler.java

@@ -8,6 +8,8 @@ import net.tcpshield.tcpshield.abstraction.IPlayer;
 import net.tcpshield.tcpshield.bukkit.impl.BukkitConfigImpl;
 import net.tcpshield.tcpshield.bukkit.paper.impl.PaperPacketImpl;
 import net.tcpshield.tcpshield.bukkit.paper.impl.PaperPlayerImpl;
+import net.tcpshield.tcpshield.bukkit.paper.impl.PaperServerListPacketImpl;
+import net.tcpshield.tcpshield.bukkit.paper.impl.PaperServerListPingPlayerImpl;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
@@ -17,11 +19,11 @@ public class PaperHandshakePacketHandler implements Listener {
 
     private final HandshakePacketHandler handshakePacketHandler;
 
-    public PaperHandshakePacketHandler(JavaPlugin plugin) {
-        this.handshakePacketHandler = new HandshakePacketHandler(plugin.getLogger(), new BukkitConfigImpl(plugin));
+    public PaperHandshakePacketHandler(HandshakePacketHandler handshakePacketHandler) {
+        this.handshakePacketHandler = handshakePacketHandler;
     }
 
-    @EventHandler(priority = EventPriority.HIGHEST)
+    @EventHandler(priority = EventPriority.LOWEST)
     public void onHandshake(PlayerHandshakeEvent e) {
         IPacket packet = new PaperPacketImpl(e);
         IPlayer player = new PaperPlayerImpl(e);
@@ -29,8 +31,13 @@ public class PaperHandshakePacketHandler implements Listener {
         handshakePacketHandler.onHandshake(packet, player);
     }
 
-    @EventHandler(priority = EventPriority.HIGHEST)
+    @EventHandler(priority = EventPriority.LOWEST)
     public void onServerPing(PaperServerListPingEvent e) {
         if (e.getClient().isLegacy()) e.setCancelled(true);
+
+        IPacket packet = new PaperServerListPacketImpl(e);
+        IPlayer player = new PaperServerListPingPlayerImpl(e);
+
+        handshakePacketHandler.onHandshake(packet, player);
     }
 }

src/main/java/net/tcpshield/tcpshield/bukkit/paper/TCPShieldPaper.java

@@ -1,5 +1,11 @@
 package net.tcpshield.tcpshield.bukkit.paper;
 
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.bukkit.impl.BukkitConfigImpl;
+import net.tcpshield.tcpshield.geyser.GeyserHandshakePacketHandler;
+import net.tcpshield.tcpshield.geyser.GeyserUtils;
+import net.tcpshield.tcpshield.velocity.VelocityHandshakePacketHandler;
+import net.tcpshield.tcpshield.velocity.impl.VelocityConfigImpl;
 import org.bukkit.Bukkit;
 import org.bukkit.plugin.java.JavaPlugin;
 
@@ -12,7 +18,11 @@ public class TCPShieldPaper {
     }
 
     public void load() {
-        PaperHandshakePacketHandler packetHandler = new PaperHandshakePacketHandler(plugin);
-        Bukkit.getPluginManager().registerEvents(packetHandler, plugin);
+        HandshakePacketHandler handshakePacketHandler =  new HandshakePacketHandler(plugin.getLogger(), new BukkitConfigImpl(plugin));
+
+        GeyserUtils.initGeyserOrDefault(handshakePacketHandler, () -> {
+            PaperHandshakePacketHandler packetHandler = new PaperHandshakePacketHandler(handshakePacketHandler);
+            Bukkit.getPluginManager().registerEvents(packetHandler, plugin);
+        });
     }
 }

src/main/java/net/tcpshield/tcpshield/bukkit/paper/impl/PaperPlayerImpl.java

@@ -1,10 +1,10 @@
 package net.tcpshield.tcpshield.bukkit.paper.impl;
 
 import com.destroystokyo.paper.event.player.PlayerHandshakeEvent;
+import net.kyori.adventure.text.Component;
 import net.tcpshield.tcpshield.abstraction.IPlayer;
 
 import java.net.InetSocketAddress;
-import java.util.UUID;
 
 public class PaperPlayerImpl implements IPlayer {
 
@@ -14,22 +14,9 @@ public class PaperPlayerImpl implements IPlayer {
         this.handshakeEvent = handshakeEvent;
     }
 
-    @Override
-    public String getUUID() {
-        UUID uuid = handshakeEvent.getUniqueId();
-        if (uuid == null) return "unknown";
-
-        return uuid.toString();
-    }
-
-    @Override
-    public String getName() {
-        return "unknown";
-    }
-
     @Override
     public String getIP() {
-        return handshakeEvent.getSocketAddressHostname();
+        return handshakeEvent.getOriginalSocketAddressHostname();
     }
 
     @Override
@@ -40,7 +27,7 @@ public class PaperPlayerImpl implements IPlayer {
     @Override
     public void disconnect() {
         handshakeEvent.setCancelled(false);
-        handshakeEvent.setFailMessage("Connection failed. Please try again or contract an administrator.");
+        handshakeEvent.failMessage(Component.text("Connection failed. Please try again or contact an administrator."));
         handshakeEvent.setFailed(true);
     }
 }

src/main/java/net/tcpshield/tcpshield/bukkit/paper/impl/PaperServerListPacketImpl.java

@@ -0,0 +1,23 @@
+package net.tcpshield.tcpshield.bukkit.paper.impl;
+
+import com.destroystokyo.paper.event.server.PaperServerListPingEvent;
+import net.tcpshield.tcpshield.abstraction.IPacket;
+
+public class PaperServerListPacketImpl implements IPacket {
+
+    private final PaperServerListPingEvent pingEvent;
+
+    public PaperServerListPacketImpl(PaperServerListPingEvent pingEvent) {
+        this.pingEvent = pingEvent;
+    }
+
+    @Override
+    public String getRawPayload() {
+        return null;
+    }
+
+    @Override
+    public void modifyOriginalPacket(String hostname) {
+        pingEvent.setCancelled(false);
+    }
+}

src/main/java/net/tcpshield/tcpshield/bukkit/paper/impl/PaperServerListPingPlayerImpl.java

@@ -0,0 +1,30 @@
+package net.tcpshield.tcpshield.bukkit.paper.impl;
+
+import com.destroystokyo.paper.event.server.PaperServerListPingEvent;
+import net.tcpshield.tcpshield.abstraction.IPlayer;
+
+import java.net.InetSocketAddress;
+
+public class PaperServerListPingPlayerImpl implements IPlayer {
+
+    private final PaperServerListPingEvent pingEvent;
+
+    public PaperServerListPingPlayerImpl(PaperServerListPingEvent pingEvent) {
+        this.pingEvent = pingEvent;
+    }
+
+    @Override
+    public String getIP() {
+        return pingEvent.getAddress().getHostAddress();
+    }
+
+    @Override
+    public void setIP(InetSocketAddress ip) {
+        // not necessary since this class is only for server list pings
+    }
+
+    @Override
+    public void disconnect() {
+        pingEvent.setCancelled(true);
+    }
+}

src/main/java/net/tcpshield/tcpshield/bukkit/protocollib/ProtocolLibHandshakePacketHandler.java

@@ -7,7 +7,6 @@ import com.comphenix.protocol.events.PacketEvent;
 import net.tcpshield.tcpshield.HandshakePacketHandler;
 import net.tcpshield.tcpshield.abstraction.IPacket;
 import net.tcpshield.tcpshield.abstraction.IPlayer;
-import net.tcpshield.tcpshield.bukkit.impl.BukkitConfigImpl;
 import net.tcpshield.tcpshield.bukkit.protocollib.impl.ProtocolLibPacketImpl;
 import net.tcpshield.tcpshield.bukkit.protocollib.impl.ProtocolLibPlayerImpl;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -16,9 +15,9 @@ public class ProtocolLibHandshakePacketHandler extends PacketAdapter {
 
     private final HandshakePacketHandler handshakePacketHandler;
 
-    public ProtocolLibHandshakePacketHandler(JavaPlugin plugin) {
-        super(plugin, ListenerPriority.HIGHEST, PacketType.Handshake.Client.SET_PROTOCOL);
-        this.handshakePacketHandler = new HandshakePacketHandler(plugin.getLogger(), new BukkitConfigImpl(plugin));
+    public ProtocolLibHandshakePacketHandler(JavaPlugin plugin, HandshakePacketHandler handshakePacketHandler) {
+        super(plugin, ListenerPriority.LOWEST, PacketType.Handshake.Client.SET_PROTOCOL);
+        this.handshakePacketHandler = handshakePacketHandler;
     }
 
     @Override

src/main/java/net/tcpshield/tcpshield/bukkit/protocollib/TCPShieldProtocolLib.java

@@ -1,5 +1,9 @@
 package net.tcpshield.tcpshield.bukkit.protocollib;
 
+import com.comphenix.protocol.ProtocolLibrary;
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.bukkit.impl.BukkitConfigImpl;
+import net.tcpshield.tcpshield.geyser.GeyserUtils;
 import org.bukkit.plugin.java.JavaPlugin;
 
 public class TCPShieldProtocolLib {
@@ -11,7 +15,10 @@ public class TCPShieldProtocolLib {
     }
 
     public void load() {
-        ProtocolLibHandshakePacketHandler packetHandler = new ProtocolLibHandshakePacketHandler(plugin);
-        com.comphenix.protocol.ProtocolLibrary.getProtocolManager().addPacketListener(packetHandler);
+        HandshakePacketHandler handshakePacketHandler = new HandshakePacketHandler(plugin.getLogger(), new BukkitConfigImpl(plugin));
+        GeyserUtils.initGeyserOrDefault(handshakePacketHandler, () -> {
+            ProtocolLibHandshakePacketHandler packetHandler = new ProtocolLibHandshakePacketHandler(plugin, handshakePacketHandler);
+            ProtocolLibrary.getProtocolManager().addPacketListener(packetHandler);
+        });
     }
 }

src/main/java/net/tcpshield/tcpshield/bukkit/protocollib/impl/ProtocolLibPlayerImpl.java

@@ -8,14 +8,11 @@ import net.tcpshield.tcpshield.exception.IPModificationFailureException;
 import net.tcpshield.tcpshield.exception.TCPShieldInitializationException;
 import org.bukkit.entity.Player;
 
-import java.lang.reflect.Field;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 
 public class ProtocolLibPlayerImpl implements IPlayer {
 
-    private static Field socketAddressField;
-    private static Field remoteAddressField;
     private static Class<?> abstractChannelClass;
     private final Player player;
     private String ip;
@@ -37,16 +34,6 @@ public class ProtocolLibPlayerImpl implements IPlayer {
         this.ip = player.getAddress().getAddress().getHostAddress();
     }
 
-    @Override
-    public String getUUID() {
-        return "unknown"; // not supported with temporary players
-    }
-
-    @Override
-    public String getName() {
-        return "unknown"; // not supported with temporary players
-    }
-
     @Override
     public String getIP() {
         return ip;

src/main/java/net/tcpshield/tcpshield/bungee/BungeeHandshakePacketHandler.java

@@ -4,13 +4,11 @@ import net.md_5.bungee.api.connection.PendingConnection;
 import net.md_5.bungee.api.event.PlayerHandshakeEvent;
 import net.md_5.bungee.api.event.ProxyPingEvent;
 import net.md_5.bungee.api.plugin.Listener;
-import net.md_5.bungee.api.plugin.Plugin;
 import net.md_5.bungee.event.EventHandler;
 import net.md_5.bungee.event.EventPriority;
 import net.tcpshield.tcpshield.HandshakePacketHandler;
 import net.tcpshield.tcpshield.abstraction.IPacket;
 import net.tcpshield.tcpshield.abstraction.IPlayer;
-import net.tcpshield.tcpshield.bungee.impl.BungeeConfigImpl;
 import net.tcpshield.tcpshield.bungee.impl.BungeePacketImpl;
 import net.tcpshield.tcpshield.bungee.impl.BungeePlayerImpl;
 
@@ -18,8 +16,8 @@ public class BungeeHandshakePacketHandler implements Listener {
 
     private final HandshakePacketHandler handshakePacketHandler;
 
-    public BungeeHandshakePacketHandler(Plugin plugin) {
-        this.handshakePacketHandler = new HandshakePacketHandler(plugin.getLogger(), new BungeeConfigImpl(plugin));
+    public BungeeHandshakePacketHandler(HandshakePacketHandler handshakePacketHandler) {
+        this.handshakePacketHandler = handshakePacketHandler;
     }
 
     @EventHandler(priority = EventPriority.LOWEST)

src/main/java/net/tcpshield/tcpshield/bungee/TCPShieldBungee.java

@@ -3,12 +3,19 @@ package net.tcpshield.tcpshield.bungee;
 import net.md_5.bungee.api.plugin.Listener;
 import net.md_5.bungee.api.plugin.Plugin;
 import net.md_5.bungee.api.plugin.PluginManager;
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.bungee.impl.BungeeConfigImpl;
+import net.tcpshield.tcpshield.geyser.GeyserUtils;
 
 public class TCPShieldBungee extends Plugin implements Listener {
 
     @Override
     public void onEnable() {
-        PluginManager pluginManager = this.getProxy().getPluginManager();
-        pluginManager.registerListener(this, new BungeeHandshakePacketHandler(this));
+        HandshakePacketHandler handshakePacketHandler = new HandshakePacketHandler(this.getLogger(), new BungeeConfigImpl(this));
+
+        GeyserUtils.initGeyserOrDefault(handshakePacketHandler, () -> {
+            PluginManager pluginManager = this.getProxy().getPluginManager();
+            pluginManager.registerListener(this, new BungeeHandshakePacketHandler(handshakePacketHandler));
+        });
     }
 }

src/main/java/net/tcpshield/tcpshield/bungee/impl/BungeeConfigImpl.java

@@ -22,7 +22,8 @@ public class BungeeConfigImpl extends TCPShieldConfig {
 
         Configuration config = loadConfig();
         this.onlyProxy = config.getBoolean("only-allow-proxy-connections");
-        this.timestampValidationMode = config.getString("timestamp-validation");
+        this.ipWhitelistFolder = new File(plugin.getDataFolder(), "ip-whitelist");
+        this.geyser = config.getBoolean("enable-geyser-compatibility");
         this.debug = config.getBoolean("debug-mode");
     }
 

src/main/java/net/tcpshield/tcpshield/bungee/impl/BungeePlayerImpl.java

@@ -9,7 +9,6 @@ import net.tcpshield.tcpshield.exception.IPModificationFailureException;
 import java.lang.reflect.Field;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
-import java.util.UUID;
 
 public class BungeePlayerImpl implements IPlayer {
 
@@ -21,19 +20,6 @@ public class BungeePlayerImpl implements IPlayer {
         this.ip = pendingConnection.getAddress().getAddress().getHostAddress();
     }
 
-    @Override
-    public String getUUID() {
-        UUID uuid = pendingConnection.getUniqueId();
-        if (uuid == null) return "Unknown";
-
-        return uuid.toString();
-    }
-
-    @Override
-    public String getName() {
-        return pendingConnection.getName();
-    }
-
     @Override
     public String getIP() {
         return ip;

src/main/java/net/tcpshield/tcpshield/exception/ConnectionNotProxiedException.java

@@ -1,16 +0,0 @@
-package net.tcpshield.tcpshield.exception;
-
-public class ConnectionNotProxiedException extends SecurityException {
-
-    public ConnectionNotProxiedException() {
-        super();
-    }
-
-    public ConnectionNotProxiedException(Throwable cause) {
-        super(cause);
-    }
-
-    public ConnectionNotProxiedException(String s) {
-        super(s);
-    }
-}

src/main/java/net/tcpshield/tcpshield/exception/InvalidIPException.java

@@ -0,0 +1,4 @@
+package net.tcpshield.tcpshield.exception;
+
+public class InvalidIPException extends SecurityException {
+}

src/main/java/net/tcpshield/tcpshield/exception/InvalidTimestampException.java

@@ -1,20 +0,0 @@
-package net.tcpshield.tcpshield.exception;
-
-public class InvalidTimestampException extends SigningVerificationFailureException {
-
-    private final long timestamp;
-    private final long currentTime;
-
-    public InvalidTimestampException(long timestamp, long currentTime) {
-        this.timestamp = timestamp;
-        this.currentTime = currentTime;
-    }
-
-    public long getTimestamp() {
-        return timestamp;
-    }
-
-    public long getCurrentTime() {
-        return currentTime;
-    }
-}

src/main/java/net/tcpshield/tcpshield/exception/MalformedPayloadException.java

@@ -1,15 +0,0 @@
-package net.tcpshield.tcpshield.exception;
-
-public class MalformedPayloadException extends ConnectionNotProxiedException {
-
-    public MalformedPayloadException() {
-    }
-
-    public MalformedPayloadException(Throwable cause) {
-        super(cause);
-    }
-
-    public MalformedPayloadException(String s) {
-        super(s);
-    }
-}

src/main/java/net/tcpshield/tcpshield/exception/SigningVerificationFailureException.java

@@ -1,8 +0,0 @@
-package net.tcpshield.tcpshield.exception;
-
-public class SigningVerificationFailureException extends MalformedPayloadException {
-
-    public SigningVerificationFailureException() {
-        super();
-    }
-}

src/main/java/net/tcpshield/tcpshield/exception/TCPShieldIPListUpdaterException.java

@@ -0,0 +1,16 @@
+package net.tcpshield.tcpshield.exception;
+
+public class TCPShieldIPListUpdaterException extends RuntimeException {
+
+    public TCPShieldIPListUpdaterException(Throwable cause) {
+        super(cause);
+    }
+
+    public TCPShieldIPListUpdaterException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public TCPShieldIPListUpdaterException(String message) {
+        super(message);
+    }
+}

src/main/java/net/tcpshield/tcpshield/fabric/TCPShieldFabric.java

@@ -0,0 +1,18 @@
+package net.tcpshield.tcpshield.fabric;
+
+import net.fabricmc.api.ModInitializer;
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.fabric.impl.FabricConfigImpl;
+
+import java.util.logging.Logger;
+
+public class TCPShieldFabric implements ModInitializer {
+
+    public static final Logger LOGGER = Logger.getLogger("TCPShield");
+    public static final HandshakePacketHandler PACKET_HANDLER =  new HandshakePacketHandler(LOGGER, new FabricConfigImpl());
+
+    @Override
+    public void onInitialize() {
+        LOGGER.info("TCPShield has been loaded.");
+    }
+}

src/main/java/net/tcpshield/tcpshield/fabric/impl/FabricConfigImpl.java

@@ -0,0 +1,105 @@
+package net.tcpshield.tcpshield.fabric.impl;
+
+import net.fabricmc.loader.api.FabricLoader;
+import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
+import net.tcpshield.tcpshield.exception.TCPShieldInitializationException;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+public class FabricConfigImpl extends TCPShieldConfig {
+
+    private final Path configLocation = new File(FabricLoader.getInstance().getConfigDir().toString(), "tcpshield.yml").toPath();
+
+    public FabricConfigImpl() {
+        if(!configExists()) {
+            createDefaultConfig();
+        }
+
+        ConfigData config = loadConfig();
+
+        this.onlyProxy = config.onlyAllowProxyConnections;
+        this.ipWhitelistFolder = new File(FabricLoader.getInstance().getGameDirectory(), "ip-whitelist");
+        this.geyser = false;
+        this.debug = config.debugMode;
+    }
+
+    /**
+     * @return  whether the file specified in {@link FabricConfigImpl#configLocation} exists.
+     */
+    private boolean configExists() {
+        return Files.exists(configLocation);
+    }
+
+    /**
+     * Creates the default configuration file at the location specified in {@link FabricConfigImpl#configLocation}.
+     *
+     * <p>
+     * This operation will always override an existing configuration file if it exists.
+     * Callers should check {@link FabricConfigImpl#configExists()} if they wish to avoid this behavior.
+     */
+    private void createDefaultConfig() {
+        // Ensure the parent directory of our config file exists.
+        // If it does not exist, attempt to create it now.
+        Path parentDirectory = configLocation.getParent();
+        if (!Files.exists(parentDirectory) || !Files.isDirectory(parentDirectory)) {
+            parentDirectory.toFile().mkdirs();
+        }
+
+        // Copy the config.yml data from our mod jar to the loader config folder.
+        try (InputStream in = getClass().getClassLoader().getResourceAsStream("config.yml")) {
+            Files.copy(in, configLocation);
+        } catch (Exception e) {
+            throw new TCPShieldInitializationException(e);
+        }
+    }
+
+    private ConfigData loadConfig() {
+        try {
+            List<String> strings = Files.readAllLines(configLocation);
+
+            boolean onlyAllowProxyConnections = true;
+            boolean debugMode = false;
+
+            // Rudimentary config parsing
+            for (String line : strings) {
+                String[] keyValue = line.split(": ");
+
+                // A config option will only be valid if it is in the format 'a: b'.
+                // Ensure that is the case now.
+                if (keyValue.length == 2) {
+                    String key = keyValue[0];
+                    String value = keyValue[1];
+
+                    switch (key) {
+                        case "only-allow-proxy-connections":
+                            onlyAllowProxyConnections = Boolean.parseBoolean(value);
+                            break;
+                        case "debug-mode":
+                            debugMode = Boolean.parseBoolean(value);
+                            break;
+                    }
+                }
+            }
+
+            return new ConfigData(onlyAllowProxyConnections, debugMode);
+        } catch (Exception e) {
+            throw new TCPShieldInitializationException("Couldn't load config in config/tclshield.yml!");
+        }
+    }
+
+    private static class ConfigData {
+
+        protected boolean onlyAllowProxyConnections;
+        protected boolean debugMode;
+
+        public ConfigData(boolean onlyAllowProxyConnections, boolean debugMode) {
+            this.onlyAllowProxyConnections = onlyAllowProxyConnections;
+            this.debugMode = debugMode;
+        }
+    }
+}

src/main/java/net/tcpshield/tcpshield/fabric/impl/FabricPacketImpl.java

@@ -0,0 +1,24 @@
+package net.tcpshield.tcpshield.fabric.impl;
+
+import net.minecraft.network.packet.c2s.handshake.HandshakeC2SPacket;
+import net.tcpshield.tcpshield.abstraction.IPacket;
+import net.tcpshield.tcpshield.fabric.mixin.HandshakeC2SPacketAccessor;
+
+public class FabricPacketImpl implements IPacket {
+
+    private final HandshakeC2SPacket handshake;
+
+    public FabricPacketImpl(HandshakeC2SPacket handshake) {
+        this.handshake = handshake;
+    }
+
+    @Override
+    public String getRawPayload() {
+        return ((HandshakeC2SPacketAccessor) handshake).getAddress();
+    }
+
+    @Override
+    public void modifyOriginalPacket(String hostname) throws Exception {
+        // NO OPERATION
+    }
+}

src/main/java/net/tcpshield/tcpshield/fabric/impl/FabricPlayerImpl.java

@@ -0,0 +1,40 @@
+package net.tcpshield.tcpshield.fabric.impl;
+
+import net.minecraft.network.ClientConnection;
+import net.minecraft.network.packet.c2s.handshake.HandshakeC2SPacket;
+import net.minecraft.network.packet.s2c.login.LoginDisconnectS2CPacket;
+import net.minecraft.text.LiteralText;
+import net.tcpshield.tcpshield.abstraction.IPlayer;
+import net.tcpshield.tcpshield.exception.IPModificationFailureException;
+import net.tcpshield.tcpshield.fabric.mixin.ClientConnectionAccessor;
+
+import java.net.InetSocketAddress;
+
+public class FabricPlayerImpl implements IPlayer {
+
+    private final ClientConnection connection;
+    private String ip;
+
+    public FabricPlayerImpl(HandshakeC2SPacket packet, ClientConnection connection) {
+        this.connection = connection;
+        this.ip = ((InetSocketAddress) ((ClientConnectionAccessor) connection).getChannel().remoteAddress()).getAddress().getHostAddress();
+    }
+
+    @Override
+    public String getIP() {
+        return ip;
+    }
+
+    @Override
+    public void setIP(InetSocketAddress ip) throws IPModificationFailureException {
+        // At this point, the IP/connection believe the player has the IP of TCPShield.
+        // The ip passed into this method contains their CORRECT data, which we have to assign to the player network connection.
+        ((ClientConnectionAccessor) connection).setAddress(ip);
+        this.ip = ((InetSocketAddress) ((ClientConnectionAccessor) connection).getChannel().remoteAddress()).getAddress().getHostAddress();
+    }
+
+    @Override
+    public void disconnect() {
+        connection.disconnect(new LiteralText("Connection failed. Please try again or contact an administrator."));
+    }
+}

src/main/java/net/tcpshield/tcpshield/fabric/mixin/ClientConnectionAccessor.java

@@ -0,0 +1,20 @@
+package net.tcpshield.tcpshield.fabric.mixin;
+
+import io.netty.channel.Channel;
+import net.minecraft.network.ClientConnection;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+import java.net.SocketAddress;
+
+@Mixin(ClientConnection.class)
+public interface ClientConnectionAccessor {
+    @Accessor
+    void setAddress(SocketAddress address);
+
+    @Accessor
+    Channel getChannel();
+
+    @Accessor
+    SocketAddress getAddress();
+}

src/main/java/net/tcpshield/tcpshield/fabric/mixin/HandshakeC2SPacketAccessor.java

@@ -0,0 +1,11 @@
+package net.tcpshield.tcpshield.fabric.mixin;
+
+import net.minecraft.network.packet.c2s.handshake.HandshakeC2SPacket;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+@Mixin(HandshakeC2SPacket.class)
+public interface HandshakeC2SPacketAccessor {
+    @Accessor
+    String getAddress();
+}

src/main/java/net/tcpshield/tcpshield/fabric/mixin/ServerHandshakeMixin.java

@@ -0,0 +1,32 @@
+package net.tcpshield.tcpshield.fabric.mixin;
+
+import net.minecraft.network.ClientConnection;
+import net.minecraft.network.packet.c2s.handshake.HandshakeC2SPacket;
+import net.minecraft.server.network.ServerHandshakeNetworkHandler;
+import net.tcpshield.tcpshield.abstraction.IPacket;
+import net.tcpshield.tcpshield.abstraction.IPlayer;
+import net.tcpshield.tcpshield.fabric.TCPShieldFabric;
+import net.tcpshield.tcpshield.fabric.impl.FabricPacketImpl;
+import net.tcpshield.tcpshield.fabric.impl.FabricPlayerImpl;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(ServerHandshakeNetworkHandler.class)
+public class ServerHandshakeMixin {
+
+    @Shadow @Final private ClientConnection connection;
+
+    @Inject(
+            method = "onHandshake",
+            at = @At("HEAD"))
+    private void onHandshake(HandshakeC2SPacket handshake, CallbackInfo ci) {
+        IPacket packet = new FabricPacketImpl(handshake);
+        IPlayer player = new FabricPlayerImpl(handshake, connection);
+
+        TCPShieldFabric.PACKET_HANDLER.onHandshake(packet, player);
+    }
+}

src/main/java/net/tcpshield/tcpshield/geyser/GeyserHandshakePacketHandler.java

@@ -0,0 +1,29 @@
+package net.tcpshield.tcpshield.geyser;
+
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.abstraction.IPacket;
+import net.tcpshield.tcpshield.abstraction.IPlayer;
+import net.tcpshield.tcpshield.geyser.impl.GeyserPacketImpl;
+import net.tcpshield.tcpshield.geyser.impl.GeyserPlayerImpl;
+import org.geysermc.floodgate.api.InstanceHolder;
+
+public class GeyserHandshakePacketHandler {
+
+    private final HandshakePacketHandler handshakePacketHandler;
+
+    public GeyserHandshakePacketHandler(HandshakePacketHandler handshakePacketHandler) {
+        this.handshakePacketHandler = handshakePacketHandler;
+    }
+
+    public void init() {
+        InstanceHolder.getHandshakeHandlers().addHandshakeHandler(data -> {
+            // In case the connection is a Bedrock connection, we don't bother
+            if (data.getBedrockData() != null) return;
+
+            IPlayer player = new GeyserPlayerImpl(data);
+            IPacket packet = new GeyserPacketImpl(data);
+
+            handshakePacketHandler.onHandshake(packet, player);
+        });
+    }
+}

src/main/java/net/tcpshield/tcpshield/geyser/GeyserUtils.java

@@ -0,0 +1,27 @@
+package net.tcpshield.tcpshield.geyser;
+
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
+
+public class GeyserUtils {
+
+    public static void initGeyserOrDefault(HandshakePacketHandler handshakePacketHandler, Runnable registrar) {
+        if (!useGeyser(handshakePacketHandler.getConfig())) {
+            registrar.run();
+        } else {
+            GeyserHandshakePacketHandler geyserHandler = new GeyserHandshakePacketHandler(handshakePacketHandler);
+            geyserHandler.init();
+        }
+    }
+
+    private static boolean useGeyser(TCPShieldConfig config) {
+        if (!config.isGeyser()) return false;
+
+        try {
+            Class.forName("org.geysermc.floodgate.api.InstanceHolder");
+            return true;
+        } catch (ClassNotFoundException e) {
+            return false;
+        }
+    }
+}

src/main/java/net/tcpshield/tcpshield/geyser/impl/GeyserPacketImpl.java

@@ -0,0 +1,23 @@
+package net.tcpshield.tcpshield.geyser.impl;
+
+import net.tcpshield.tcpshield.abstraction.IPacket;
+import org.geysermc.floodgate.api.handshake.HandshakeData;
+
+public class GeyserPacketImpl implements IPacket {
+
+    private final HandshakeData handshakeData;
+
+    public GeyserPacketImpl(HandshakeData handshakeData) {
+        this.handshakeData = handshakeData;
+    }
+
+    @Override
+    public String getRawPayload() {
+        return handshakeData.getHostname();
+    }
+
+    @Override
+    public void modifyOriginalPacket(String hostname) {
+        handshakeData.setHostname(hostname);
+    }
+}

src/main/java/net/tcpshield/tcpshield/geyser/impl/GeyserPlayerImpl.java

@@ -0,0 +1,30 @@
+package net.tcpshield.tcpshield.geyser.impl;
+
+import net.tcpshield.tcpshield.abstraction.IPlayer;
+import org.geysermc.floodgate.api.handshake.HandshakeData;
+
+import java.net.InetSocketAddress;
+
+public class GeyserPlayerImpl implements IPlayer {
+
+    private final HandshakeData handshakeData;
+
+    public GeyserPlayerImpl(HandshakeData handshakeData) {
+        this.handshakeData = handshakeData;
+    }
+
+    @Override
+    public String getIP() {
+        return ((InetSocketAddress) handshakeData.getChannel().remoteAddress()).getAddress().getHostAddress();
+    }
+
+    @Override
+    public void setIP(InetSocketAddress ip) {
+        handshakeData.setIp(ip.getAddress().getHostAddress());
+    }
+
+    @Override
+    public void disconnect() {
+        handshakeData.getChannel().close();
+    }
+}

src/main/java/net/tcpshield/tcpshield/validation/IPListAutoUpdater.java

@@ -0,0 +1,24 @@
+package net.tcpshield.tcpshield.validation;
+
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.TimeUnit;
+
+public class IPListAutoUpdater {
+
+    private final IPListUpdater ipListUpdater;
+
+    public IPListAutoUpdater(IPListUpdater ipListUpdater) {
+        this.ipListUpdater = ipListUpdater;
+    }
+
+    public void init() {
+        new Timer().scheduleAtFixedRate(new TimerTask() {
+            @Override
+            public void run() {
+                ipListUpdater.update();
+            }
+        }, TimeUnit.HOURS.toMillis(12), TimeUnit.HOURS.toMillis(12));
+    }
+
+}

src/main/java/net/tcpshield/tcpshield/validation/IPListUpdater.java

@@ -0,0 +1,80 @@
+package net.tcpshield.tcpshield.validation;
+
+import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
+import net.tcpshield.tcpshield.exception.TCPShieldIPListUpdaterException;
+import net.tcpshield.tcpshield.validation.cidr.CIDRMatcher;
+
+import javax.net.ssl.HttpsURLConnection;
+import java.io.*;
+import java.net.URL;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+public class IPListUpdater {
+
+    private final TCPShieldConfig config;
+    private final IPValidation ipValidation;
+    private final Logger logger;
+
+    public IPListUpdater(TCPShieldConfig config, IPValidation ipValidation, Logger logger) {
+        this.config = config;
+        this.ipValidation = ipValidation;
+        this.logger = logger;
+    }
+
+    public void update() {
+        try {
+            String ipList = getIPList();
+
+            File ipWhitelistFolder = config.getIPWhitelistFolder();
+            File tcpShieldIPList = new File(ipWhitelistFolder, "tcpshield-ips.list");
+
+            if (tcpShieldIPList.createNewFile()) {
+                logger.info("Fetched updated IP Whitelist from https://tcpshield.com/v4/");
+            }
+
+            try (FileWriter writer = new FileWriter(tcpShieldIPList, false)) {
+                writer.write(ipList);
+            }
+
+            ipValidation.readIPWhitelist();
+        } catch (Exception e) {
+            throw new TCPShieldIPListUpdaterException(e);
+        }
+    }
+
+    public String getIPList() throws IOException {
+        URL url = new URL("https://tcpshield.com/v4/");
+
+        HttpsURLConnection connection = null;
+        try {
+            connection = (HttpsURLConnection) url.openConnection();
+
+            try (InputStream inputStream = connection.getInputStream();
+                 BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream))) {
+                int responseCode = connection.getResponseCode();
+                if (responseCode != 200)
+                    throw new TCPShieldIPListUpdaterException("https://tcpshield.com/v4/ did not return status code 200: " + responseCode);
+
+                String data = bufferedReader.lines()
+                        .filter(str -> !str.isEmpty())
+                        .peek(cidr -> {  // checks for validity of each CIDR entry
+                            try {
+                                new CIDRMatcher(cidr);
+                            } catch (Exception e) {
+                                throw new TCPShieldIPListUpdaterException("https://tcpshield.com/v4/ returned a faulty CIDR entry: " + cidr, e);
+                            }
+                        })
+                        .collect(Collectors.joining("\n"));
+
+                if (data.isEmpty())
+                    throw new TCPShieldIPListUpdaterException("Response from https://tcpshield.com/v4/ empty");
+
+                return data;
+            }
+        } finally {
+            if (connection != null)
+                connection.disconnect();
+        }
+    }
+}

src/main/java/net/tcpshield/tcpshield/validation/IPValidation.java

@@ -0,0 +1,69 @@
+package net.tcpshield.tcpshield.validation;
+
+import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
+import net.tcpshield.tcpshield.exception.TCPShieldInitializationException;
+import net.tcpshield.tcpshield.validation.cidr.CIDRChecker;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Scanner;
+import java.util.logging.Logger;
+
+public class IPValidation {
+
+    private final TCPShieldConfig config;
+    private final IPListUpdater ipListUpdater;
+    private final CIDRChecker cidrChecker;
+
+    private List<String> ipWhitelist = new ArrayList<>();
+
+    public IPValidation(TCPShieldConfig config, Logger logger) {
+        this.config = config;
+        this.ipListUpdater = new IPListUpdater(config, this, logger);
+        new IPListAutoUpdater(ipListUpdater).init();
+
+        checkIPList();
+
+        try {
+            readIPWhitelist();
+            this.cidrChecker = new CIDRChecker(ipWhitelist);
+        } catch (IOException e) {
+            throw new TCPShieldInitializationException(e);
+        }
+    }
+
+    public boolean validateIP(InetAddress inetAddress) {
+        return cidrChecker.check(inetAddress);
+    }
+
+    private List<String> getIPWhitelist() throws IOException {
+        List<String> ipWhitelist = new ArrayList<>();
+
+        for (File file : Objects.requireNonNull(config.getIPWhitelistFolder().listFiles())) {
+            if (file.isDirectory()) continue;
+
+            try (Scanner scanner = new Scanner(file)) {
+                while (scanner.hasNextLine()) {
+                    String cidrEntry = scanner.nextLine();
+                    ipWhitelist.add(cidrEntry);
+                }
+            }
+        }
+
+        return ipWhitelist;
+    }
+
+    public void readIPWhitelist() throws IOException {
+        this.ipWhitelist = getIPWhitelist();
+    }
+
+    private void checkIPList() {
+        if (config.getIPWhitelistFolder().mkdirs()) {
+            ipListUpdater.update();
+        }
+    }
+}

src/main/java/net/tcpshield/tcpshield/validation/ITimestampValidator.java

@@ -1,11 +0,0 @@
-package net.tcpshield.tcpshield.validation;
-
-public interface ITimestampValidator {
-
-    boolean validateTimestamp(long checkedTimestamp);
-
-    default long getTime() {
-        return System.currentTimeMillis() / 1000;
-    }
-
-}

src/main/java/net/tcpshield/tcpshield/validation/TimestampValidation.java

@@ -1,34 +0,0 @@
-package net.tcpshield.tcpshield.validation;
-
-import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
-import net.tcpshield.tcpshield.validation.impl.DisabledTimestampValidatorImpl;
-import net.tcpshield.tcpshield.validation.impl.HTPDateTimestampValidatorImpl;
-import net.tcpshield.tcpshield.validation.impl.SystemTimeTimestampValidatorImpl;
-
-public class TimestampValidation {
-
-    private final ITimestampValidator timestampValidator;
-
-    public TimestampValidation(TCPShieldConfig config) {
-        switch (config.getTimestampValidationMode().toLowerCase()) {
-            case "system":
-                this.timestampValidator = new SystemTimeTimestampValidatorImpl();
-                break;
-            case "off":
-                this.timestampValidator = new DisabledTimestampValidatorImpl();
-                break;
-            case "htpdate":
-            default:
-                this.timestampValidator = new HTPDateTimestampValidatorImpl();
-        }
-    }
-
-    public boolean checkTimestamp(long timestamp) {
-        return timestampValidator.validateTimestamp(timestamp);
-    }
-
-    public long getTime() {
-        return timestampValidator.getTime();
-    }
-
-}

src/main/java/net/tcpshield/tcpshield/validation/cidr/CIDRChecker.java

@@ -0,0 +1,38 @@
+package net.tcpshield.tcpshield.validation.cidr;
+
+import java.net.InetAddress;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class CIDRChecker {
+
+    private final List<CIDRMatcher> cidrMatchers = new ArrayList<>();
+    private final Set<String> cache = new HashSet<>(); // quick cache for already verified IPs; HashSet is O(1) on HashSet#contains() operations
+
+    public CIDRChecker(List<String> cidrList) {
+        for (String cidr : cidrList) {
+            CIDRMatcher cidrMatcher = new CIDRMatcher(cidr);
+            cidrMatchers.add(cidrMatcher);
+        }
+    }
+
+    public boolean check(InetAddress inetAddress) {
+        String ip = inetAddress.getHostAddress();
+        if (cache.contains(ip)) return true;
+
+        if (!checkUncached(inetAddress)) return false;
+
+        cache.add(ip);
+        return true;
+    }
+
+    private boolean checkUncached(InetAddress inetAddress) {
+        for (CIDRMatcher cidrMatcher : cidrMatchers) {
+            if (cidrMatcher.matches(inetAddress)) return true;
+        }
+
+        return false;
+    }
+}

src/main/java/net/tcpshield/tcpshield/validation/cidr/CIDRMatcher.java

@@ -0,0 +1,59 @@
+package net.tcpshield.tcpshield.validation.cidr;
+
+import net.tcpshield.tcpshield.exception.TCPShieldInitializationException;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+public class CIDRMatcher {
+
+    private final int maskBits;
+    private final int maskBytes;
+    private final boolean simpleCIDR;
+    private final InetAddress cidrAddress;
+
+    public CIDRMatcher(String ipAddress) {
+        String[] split = ipAddress.split("/");
+
+        String parsedIPAddress;
+        if (split.length >= 2) {
+            parsedIPAddress = split[0];
+
+            this.maskBits = Integer.parseInt(split[1]);
+            this.simpleCIDR = maskBits == 32;
+        } else {
+            parsedIPAddress = ipAddress;
+
+            this.maskBits = -1;
+            this.simpleCIDR = true;
+        }
+
+        this.maskBytes = simpleCIDR ? -1 : maskBits / 8;
+
+        try {
+            cidrAddress = InetAddress.getByName(parsedIPAddress);
+        } catch (UnknownHostException e) {
+            throw new TCPShieldInitializationException(e);
+        }
+    }
+
+    public boolean matches(InetAddress inetAddress) {
+        if (!cidrAddress.getClass().equals(inetAddress.getClass())) return false; // check if IP is IPv4 or IPv6
+
+        if (simpleCIDR) return inetAddress.equals(cidrAddress); // check for equality if it's a simple CIDR
+
+        byte[] inetAddressBytes = inetAddress.getAddress();
+        byte[] requiredAddressBytes = cidrAddress.getAddress();
+
+        byte finalByte = (byte) (0xFF00 >> (maskBits & 0x07));
+
+        for (int i = 0; i < maskBytes; i++) {
+            if (inetAddressBytes[i] != requiredAddressBytes[i]) return false;
+        }
+
+        if (finalByte != 0)
+            return (inetAddressBytes[maskBytes] & finalByte) == (requiredAddressBytes[maskBytes] & finalByte);
+
+        return true;
+    }
+}

src/main/java/net/tcpshield/tcpshield/validation/impl/DisabledTimestampValidatorImpl.java

@@ -1,13 +0,0 @@
-package net.tcpshield.tcpshield.validation.impl;
-
-import net.tcpshield.tcpshield.validation.ITimestampValidator;
-
-/**
- * @author Fuzzlemann
- */
-public class DisabledTimestampValidatorImpl implements ITimestampValidator {
-    @Override
-    public boolean validateTimestamp(long checkedTimestamp) {
-        return true;
-    }
-}

src/main/java/net/tcpshield/tcpshield/validation/impl/HTPDateTimestampValidatorImpl.java

@@ -1,81 +0,0 @@
-package net.tcpshield.tcpshield.validation.impl;
-
-import net.tcpshield.tcpshield.Constants;
-import net.tcpshield.tcpshield.validation.ITimestampValidator;
-
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStreamReader;
-import java.net.Socket;
-import java.nio.charset.StandardCharsets;
-import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.List;
-import java.util.Locale;
-import java.util.concurrent.ForkJoinPool;
-import java.util.stream.Collectors;
-
-/**
- * inspired by https://github.com/iridium77/htpdate/blob/master/htpdate.c
- */
-public class HTPDateTimestampValidatorImpl implements ITimestampValidator {
-
-    private volatile long timestampOffset = 0;
-
-    public HTPDateTimestampValidatorImpl() {
-        ForkJoinPool.commonPool().submit(() -> {
-            try {
-                syncTimestamp();
-            } catch (Exception e) {
-                e.printStackTrace();
-            }
-        }); // do not execute network requests on the main thread
-    }
-
-    @Override
-    public boolean validateTimestamp(long checkedTimestamp) {
-        long currentTime = getTime();
-
-        return checkedTimestamp >= (currentTime - Constants.MAX_TIME_DIFFERENCE) && checkedTimestamp <= (currentTime + Constants.MAX_TIME_DIFFERENCE);
-    }
-
-    private void syncTimestamp() throws IOException {
-        try (Socket socket = new Socket("google.com", 80)) {
-            // no-cache forces the server to return time
-            String payload = "HEAD http://google.com/ HTTP/1.1\r\nHost: google.com\r\nUser-Agent: tcpshield/1.0\r\nPragma: no-cache\r\nCache-Control: no-cache\r\nConnection: close\r\n\r\n";
-            socket.getOutputStream().write(payload.getBytes());
-
-            long readTime = System.currentTimeMillis(); // assuming server -> client time is negligible
-
-            List<String> response = new BufferedReader(new InputStreamReader(socket.getInputStream(), StandardCharsets.UTF_8))
-                    .lines()
-                    .collect(Collectors.toList());
-
-            Date serverDate = extractDate(response);
-
-            timestampOffset = Math.round((serverDate.getTime() - readTime) / 1000.0) * 1000; // the HTTP protocol only returns time in seconds; round offset
-        }
-    }
-
-    private Date extractDate(List<String> response) {
-        for (String line : response) {
-            if (!line.startsWith("Date: ")) continue;
-
-            String dateString = line.substring("Date: ".length());
-            SimpleDateFormat sdf = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.ENGLISH);
-            try {
-                return sdf.parse(dateString);
-            } catch (ParseException e) {
-                throw new IllegalStateException(e);
-            }
-        }
-
-        throw new IllegalArgumentException("no date line found - response: " + response);
-    }
-
-    @Override
-    public long getTime() {
-        return (System.currentTimeMillis() + timestampOffset) / 1000;
-    }
-}

src/main/java/net/tcpshield/tcpshield/validation/impl/SystemTimeTimestampValidatorImpl.java

@@ -1,14 +0,0 @@
-package net.tcpshield.tcpshield.validation.impl;
-
-import net.tcpshield.tcpshield.Constants;
-import net.tcpshield.tcpshield.validation.ITimestampValidator;
-
-public class SystemTimeTimestampValidatorImpl implements ITimestampValidator {
-
-    @Override
-    public boolean validateTimestamp(long checkedTimestamp) {
-        long currentTime = getTime();
-
-        return checkedTimestamp >= (currentTime - Constants.MAX_TIME_DIFFERENCE) && checkedTimestamp <= (currentTime + Constants.MAX_TIME_DIFFERENCE);
-    }
-}

src/main/java/net/tcpshield/tcpshield/velocity/TCPShieldVelocity.java

@@ -6,6 +6,9 @@ import com.velocitypowered.api.event.proxy.ProxyInitializeEvent;
 import com.velocitypowered.api.plugin.Plugin;
 import com.velocitypowered.api.plugin.annotation.DataDirectory;
 import com.velocitypowered.api.proxy.ProxyServer;
+import net.tcpshield.tcpshield.HandshakePacketHandler;
+import net.tcpshield.tcpshield.geyser.GeyserUtils;
+import net.tcpshield.tcpshield.velocity.impl.VelocityConfigImpl;
 
 import java.nio.file.Path;
 import java.util.logging.Logger;
@@ -29,6 +32,8 @@ public class TCPShieldVelocity {
 
     @Subscribe
     public void onProxyInitialization(ProxyInitializeEvent e) {
-        server.getEventManager().register(this, new VelocityHandshakePacketHandler(logger, dataFolder.toFile()));
+        HandshakePacketHandler handshakePacketHandler = new HandshakePacketHandler(this.logger, new VelocityConfigImpl(dataFolder.toFile()));
+
+        GeyserUtils.initGeyserOrDefault(handshakePacketHandler, () -> server.getEventManager().register(this, new VelocityHandshakePacketHandler(handshakePacketHandler)));
     }
 }

src/main/java/net/tcpshield/tcpshield/velocity/VelocityHandshakePacketHandler.java

@@ -7,19 +7,15 @@ import com.velocitypowered.api.event.proxy.ProxyPingEvent;
 import com.velocitypowered.api.proxy.InboundConnection;
 import net.tcpshield.tcpshield.HandshakePacketHandler;
 import net.tcpshield.tcpshield.abstraction.IPacket;
-import net.tcpshield.tcpshield.velocity.impl.VelocityConfigImpl;
 import net.tcpshield.tcpshield.velocity.impl.VelocityPacketImpl;
 import net.tcpshield.tcpshield.velocity.impl.VelocityPlayerImpl;
 
-import java.io.File;
-import java.util.logging.Logger;
-
 public class VelocityHandshakePacketHandler {
 
     private final HandshakePacketHandler handshakePacketHandler;
 
-    public VelocityHandshakePacketHandler(Logger logger, File dataFolder) {
-        this.handshakePacketHandler = new HandshakePacketHandler(logger, new VelocityConfigImpl(dataFolder));
+    public VelocityHandshakePacketHandler(HandshakePacketHandler handshakePacketHandler) {
+        this.handshakePacketHandler = handshakePacketHandler;
     }
 
     @Subscribe(order = PostOrder.FIRST)

src/main/java/net/tcpshield/tcpshield/velocity/impl/VelocityConfigImpl.java

@@ -20,7 +20,8 @@ public class VelocityConfigImpl extends TCPShieldConfig {
         saveDefaultConfig();
         Toml toml = loadConfig();
         this.onlyProxy = toml.getBoolean("only-allow-proxy-connections");
-        this.timestampValidationMode = toml.getString("timestamp-validation");
+        this.ipWhitelistFolder = new File(dataFolder, "ip-whitelist");
+        this.geyser = toml.getBoolean("enable-geyser-compatibility");
         this.debug = toml.getBoolean("debug-mode");
     }
 

src/main/java/net/tcpshield/tcpshield/velocity/impl/VelocityPlayerImpl.java

@@ -12,7 +12,7 @@ import java.net.InetSocketAddress;
 
 public class VelocityPlayerImpl implements IPlayer {
 
-    private static final Class<?> initialInboundConnectionClass;
+    private static final Class<?> INITIAL_INBOUND_CONNECTION_CLASS;
     private static final Field MINECRAFT_CONNECTION_FIELD;
     private static final Field LEGACY_MINECRAFT_CONNECTION_FIELD;
     private static final Field REMOTE_ADDRESS_FIELD;
@@ -20,8 +20,8 @@ public class VelocityPlayerImpl implements IPlayer {
 
     static {
         try {
-            initialInboundConnectionClass = Class.forName("com.velocitypowered.proxy.connection.client.InitialInboundConnection");
-            MINECRAFT_CONNECTION_FIELD = ReflectionUtils.getPrivateField(initialInboundConnectionClass, "connection");
+            INITIAL_INBOUND_CONNECTION_CLASS = Class.forName("com.velocitypowered.proxy.connection.client.InitialInboundConnection");
+            MINECRAFT_CONNECTION_FIELD = ReflectionUtils.getPrivateField(INITIAL_INBOUND_CONNECTION_CLASS, "connection");
             LEGACY_MINECRAFT_CONNECTION_FIELD = ReflectionUtils.getPrivateField(Class.forName("com.velocitypowered.proxy.connection.client.HandshakeSessionHandler$LegacyInboundConnection"), "connection");
 
             Class<?> minecraftConnection = Class.forName("com.velocitypowered.proxy.connection.MinecraftConnection");
@@ -38,20 +38,10 @@ public class VelocityPlayerImpl implements IPlayer {
 
     public VelocityPlayerImpl(InboundConnection inboundConnection) {
         this.inboundConnection = inboundConnection;
-        this.legacy = inboundConnection.getClass() != initialInboundConnectionClass;
+        this.legacy = inboundConnection.getClass() != INITIAL_INBOUND_CONNECTION_CLASS;
         this.ip = inboundConnection.getRemoteAddress().getAddress().getHostAddress();
     }
 
-    @Override
-    public String getUUID() {
-        return "unknown"; // not supported
-    }
-
-    @Override
-    public String getName() {
-        return "unknown"; // not supported
-    }
-
     @Override
     public String getIP() {
         return ip;

src/main/resources/bungee.yml

@@ -1,4 +1,6 @@
 name: TCPShield
-version: '2.3'
+version: '2.5'
 main: net.tcpshield.tcpshield.bungee.TCPShieldBungee
 author: https://tcpshield.com
+softDepends:
+- floodgate

src/main/resources/config.toml

@@ -1,8 +1,8 @@
 # Please keep this as true in while using TCPShield!
 only-allow-proxy-connections = true
 
-# available modes: system (uses the system time), htpdate (uses a synchronized date) & off (deactivates timestamp validation)
-timestamp-validation = 'htpdate'
+# Only set this to true in case you're using TCPShield's Geyser proxy!
+enable-geyser-compatibility = false
 
 # Turn on to diagnose connection issues
 debug-mode = false

src/main/resources/config.yml

@@ -1,8 +1,8 @@
 # Please keep this as true in while using TCPShield!
 only-allow-proxy-connections: true
 
-# available modes: system (uses the system time), htpdate (uses a synchronized date) & off (deactivates timestamp validation)
-timestamp-validation: 'htpdate'
+# Only set this to true in case you're using TCPShield's Geyser proxy!
+enable-geyser-compatibility: false
 
 # Turn on to diagnose connection issues
 debug-mode: false

src/main/resources/fabric.mod.json

@@ -0,0 +1,27 @@
+{
+  "schemaVersion": 1,
+  "id": "tcp-shield",
+  "version": "2.5",
+  "name": "TCPShield",
+  "description": "TCPShield IP parsing capabilities for Fabric",
+  "authors": [
+    "TCPShield"
+  ],
+  "contact": {
+    "homepage": "https://tcpshield.com"
+  },
+  "license": "MIT",
+  "environment": "*",
+  "entrypoints": {
+    "main": [
+      "net.tcpshield.tcpshield.fabric.TCPShieldFabric"
+    ]
+  },
+  "mixins": [
+    "tcpshield.mixins.json"
+  ],
+  "depends": {
+    "fabricloader": "*",
+    "minecraft": "*"
+  }
+}

src/main/resources/plugin.yml

@@ -1,6 +1,8 @@
 name: TCPShield
-version: '2.3'
+version: '2.5'
 main: net.tcpshield.tcpshield.bukkit.TCPShieldBukkit
 softdepend:
 - ProtocolLib
+- floodgate
 author: https://tcpshield.com
+api-version: 1.16

src/main/resources/tcpshield.mixins.json

@@ -0,0 +1,14 @@
+{
+  "required": true,
+  "minVersion": "0.8",
+  "package": "net.tcpshield.tcpshield.fabric.mixin",
+  "compatibilityLevel": "JAVA_8",
+  "mixins": [
+    "ClientConnectionAccessor",
+    "HandshakeC2SPacketAccessor",
+    "ServerHandshakeMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  }
+}

src/main/resources/velocity-plugin.json

@@ -1,11 +1,16 @@
 {
   "id": "tcpshield",
   "name": "TCPShield",
-  "version": "2.3",
+  "version": "2.5",
   "description": "TCPShield IP parsing capabilities for Velocity",
   "authors": [
     "TCPShield"
   ],
-  "dependencies": [],
+  "dependencies": [
+    {
+      "id": "floodgate",
+      "optional": true
+    }
+  ],
   "main": "net.tcpshield.tcpshield.velocity.TCPShieldVelocity"
 }

src/test/java/net/tcpshield/tcpshield/HandshakePacketHandlerTest.java

@@ -9,27 +9,25 @@ import org.junit.jupiter.api.Test;
 
 import java.util.logging.Logger;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 
 public class HandshakePacketHandlerTest {
 
-    private final TCPShieldConfig defaultTestConfig = new TestConfigImpl("system");
-    private final TCPShieldConfig skippingTimestampCheckTestConfig = new TestConfigImpl("off");
+    private final TCPShieldConfig defaultTestConfig = new TestConfigImpl();
     private final HandshakePacketHandler standardHandshakePacketHandler = new HandshakePacketHandler(Logger.getLogger("TCPShield"), defaultTestConfig);
-    private final HandshakePacketHandler skippingTimestampCheckHandshakePacketHandler = new HandshakePacketHandler(Logger.getLogger("TCPShield"), skippingTimestampCheckTestConfig);
     private TestPlayerImpl player;
 
     @BeforeEach
     public void setUp() {
-        player = new TestPlayerImpl();
+        player = new TestPlayerImpl(TestConstants.VALID_IP);
     }
 
     @Test
     public void testSuccessfulHandshake() {
-        TestPacketImpl packet = new TestPacketImpl(TestConstants.VALID_PAYLOAD_INVALID_TIMESTAMP, TestConstants.STANDARD_HOSTNAME);
+        TestPacketImpl packet = new TestPacketImpl(TestConstants.VALID_PAYLOAD, TestConstants.STANDARD_HOSTNAME);
 
-        skippingTimestampCheckHandshakePacketHandler.onHandshake(packet, player);
+        standardHandshakePacketHandler.onHandshake(packet, player);
 
         assertEquals(TestConstants.PAYLOAD_HOSTNAME, packet.getHostname());
         assertEquals(TestConstants.PAYLOAD_IP, player.getIP());
@@ -39,36 +37,19 @@ public class HandshakePacketHandlerTest {
     public void testSuccessfulFMLTaggedHandshake() {
         TestPacketImpl packet = new TestPacketImpl(TestConstants.VALID_PAYLOAD_INVALID_TIMESTAMP_FML_TAGGED, TestConstants.STANDARD_HOSTNAME);
 
-        skippingTimestampCheckHandshakePacketHandler.onHandshake(packet, player);
+        standardHandshakePacketHandler.onHandshake(packet, player);
 
         assertEquals(TestConstants.PAYLOAD_FML_HOSTNAME, packet.getHostname());
         assertEquals(TestConstants.PAYLOAD_IP, player.getIP());
     }
 
     @Test
-    public void testUnsuccessfulHandshakeFailedTimestampCheck() {
-        TestPacketImpl packet = new TestPacketImpl(TestConstants.VALID_PAYLOAD_INVALID_TIMESTAMP, TestConstants.STANDARD_HOSTNAME);
+    public void testUnsuccessfulHandshakeInvalidIP() {
+        TestPacketImpl packet = new TestPacketImpl(TestConstants.VALID_PAYLOAD, TestConstants.STANDARD_HOSTNAME);
 
+        TestPlayerImpl player = new TestPlayerImpl(TestConstants.INVALID_IP);
         standardHandshakePacketHandler.onHandshake(packet, player);
 
         assertFalse(player.isConnected());
     }
-
-    @Test
-    public void testUnsuccessfulHandshakeMalformedPayload() {
-        TestPacketImpl packet = new TestPacketImpl(TestConstants.INVALID_PAYLOAD_MALFORMED_PAYLOAD, TestConstants.STANDARD_HOSTNAME);
-
-        skippingTimestampCheckHandshakePacketHandler.onHandshake(packet, player);
-
-        assertFalse(player.isConnected());
-    }
-
-    @Test
-    public void testUnsuccessfulHandshakeInvalidSignature() {
-        TestPacketImpl packet = new TestPacketImpl(TestConstants.INVALID_PAYLOAD_INVALID_SIGNATURE, TestConstants.STANDARD_HOSTNAME);
-
-        skippingTimestampCheckHandshakePacketHandler.onHandshake(packet, player);
-
-        assertFalse(player.isConnected());
-    }
 }

src/test/java/net/tcpshield/tcpshield/SignatureObjectVerifierTest.java

@@ -1,60 +0,0 @@
-package net.tcpshield.tcpshield;
-
-import org.junit.jupiter.api.BeforeAll;
-import org.junit.jupiter.api.Test;
-
-import java.io.IOException;
-import java.security.NoSuchAlgorithmException;
-import java.security.spec.InvalidKeySpecException;
-
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-public class SignatureObjectVerifierTest {
-
-    private static SignatureVerifier signatureVerifier;
-
-    @BeforeAll
-    public static void setUp() throws NoSuchAlgorithmException, IOException, InvalidKeySpecException {
-        signatureVerifier = new SignatureVerifier();
-    }
-
-    @Test
-    public void testVerificationSuccess() {
-        SignatureObject signatureObject = createSignature(TestConstants.VALID_PAYLOAD_INVALID_TIMESTAMP);
-        assertTrue(signatureVerifier.verify(signatureObject.getReconstructedPayload(), signatureObject.getSignature()));
-    }
-
-    @Test
-    public void testVerificationFailure() {
-        SignatureObject signatureObject = createSignature(TestConstants.INVALID_PAYLOAD_INVALID_SIGNATURE);
-        assertFalse(signatureVerifier.verify(signatureObject.getReconstructedPayload(), signatureObject.getSignature()));
-    }
-
-    private SignatureObject createSignature(String payload) {
-        int signatureIndex = payload.lastIndexOf("///");
-        String signature = payload.substring(signatureIndex + 3);
-        String reconstructedPayload = payload.substring(0, signatureIndex);
-
-        return new SignatureObject(signature, reconstructedPayload);
-    }
-
-    private static class SignatureObject {
-
-        private final String signature;
-        private final String reconstructedPayload;
-
-        private SignatureObject(String signature, String reconstructedPayload) {
-            this.signature = signature;
-            this.reconstructedPayload = reconstructedPayload;
-        }
-
-        public String getSignature() {
-            return signature;
-        }
-
-        public String getReconstructedPayload() {
-            return reconstructedPayload;
-        }
-    }
-}

src/test/java/net/tcpshield/tcpshield/TestConstants.java

@@ -4,13 +4,14 @@ public class TestConstants {
 
     public static final String STANDARD_HOSTNAME = "example.org";
 
+    public static final String VALID_IP = "51.161.19.224";
+    public static final String INVALID_IP = "1.1.1.1";
+
     public static final String PAYLOAD_HOSTNAME = "homeserver.fuzzlemann.de";
     public static final String PAYLOAD_FML_HOSTNAME = "homeserver.fuzzlemann.de\0FML\0";
     public static final String PAYLOAD_IP = "79.227.33.179";
 
-    public static final String VALID_PAYLOAD_INVALID_TIMESTAMP = "homeserver.fuzzlemann.de///79.227.33.179:53462///1589573485///MGQCMHFac1If9Y8vGAkZMTVapmC6l4M7EfD0YJ0b3pQy73IFjEPsOQn+yxp9lAKSZz7X3AIwGJ2rSxGu4JvlW5sm0pyzqUrc6mfd0xHUWC9JkusrSBSKDfiFV7TCmSZc0gGivgTs";
-    public static final String VALID_PAYLOAD_INVALID_TIMESTAMP_FML_TAGGED = VALID_PAYLOAD_INVALID_TIMESTAMP + "\0FML\0";
-    public static final String INVALID_PAYLOAD_INVALID_SIGNATURE = VALID_PAYLOAD_INVALID_TIMESTAMP + "_INVALID_SIGNATURE";
-    public static final String INVALID_PAYLOAD_MALFORMED_PAYLOAD = "MALFORMED_PAYLOAD";
+    public static final String VALID_PAYLOAD = "homeserver.fuzzlemann.de///79.227.33.179:53462///1589573485///MGQCMHFac1If9Y8vGAkZMTVapmC6l4M7EfD0YJ0b3pQy73IFjEPsOQn+yxp9lAKSZz7X3AIwGJ2rSxGu4JvlW5sm0pyzqUrc6mfd0xHUWC9JkusrSBSKDfiFV7TCmSZc0gGivgTs";
+    public static final String VALID_PAYLOAD_INVALID_TIMESTAMP_FML_TAGGED = VALID_PAYLOAD + "\0FML\0";
 
 }

src/test/java/net/tcpshield/tcpshield/impl/TestConfigImpl.java

@@ -2,10 +2,12 @@ package net.tcpshield.tcpshield.impl;
 
 import net.tcpshield.tcpshield.abstraction.TCPShieldConfig;
 
+import java.io.File;
+
 public class TestConfigImpl extends TCPShieldConfig {
 
-    public TestConfigImpl(String timestampValidationMode) {
-        this.timestampValidationMode = timestampValidationMode;
+    public TestConfigImpl() {
+        this.ipWhitelistFolder = new File("ip-whitelist");
         this.debug = true;
         this.onlyProxy = true;
     }

src/test/java/net/tcpshield/tcpshield/impl/TestPlayerImpl.java

@@ -2,37 +2,34 @@ package net.tcpshield.tcpshield.impl;
 
 import net.tcpshield.tcpshield.abstraction.IPlayer;
 
+import java.net.InetAddress;
 import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
 
 public class TestPlayerImpl implements IPlayer {
 
-    private InetSocketAddress ip;
+    private InetAddress ip;
     private boolean connected;
 
-    public TestPlayerImpl() {
+    public TestPlayerImpl(String ip) {
         this.connected = true;
-    }
-
-    @Override
-    public String getUUID() {
-        return "uuid";
-    }
-
-    @Override
-    public String getName() {
-        return "name";
+        try {
+            this.ip = InetAddress.getByName(ip);
+        } catch (UnknownHostException e) {
+            e.printStackTrace();
+        }
     }
 
     @Override
     public String getIP() {
         if (ip == null) return "ip";
 
-        return ip.getAddress().getHostAddress();
+        return ip.getHostAddress();
     }
 
     @Override
     public void setIP(InetSocketAddress ip) {
-        this.ip = ip;
+        this.ip = ip.getAddress();
     }
 
     @Override