TCPShield Fabric support (1.16.5 through 1.18.2)

build.gradle

@@ -21,12 +21,13 @@ buildscript {
 plugins {
     id 'java'
     id 'idea'
+    id 'fabric-loom' version '0.6-SNAPSHOT'
 }
 
 // --
 // Variables
 // --
-version = '2.6.1'
+version = '2.6.2'
 group = 'net.tcpshield.tcpshield'
 archivesBaseName = 'TCPShield'
 
@@ -90,6 +91,9 @@ repositories {
     maven {
         url = "https://repo.opencollab.dev/maven-snapshots/"
     }
+    maven {
+        url = 'https://maven.fabricmc.net/'
+    }
 }
 
 dependencies {
@@ -106,6 +110,11 @@ 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'
@@ -128,8 +137,8 @@ configurations {
 }
 
 task updateVersion {
-    updateYamls()
-    updateJsons()
+//    updateYamls()
+//    updateJsons()
 }
 
 void updateYamls() {

settings.gradle

@@ -1,2 +1,11 @@
-rootProject.name = 'TCPShield'
+pluginManagement {
+    repositories {
+        maven {
+            name = 'Fabric'
+            url = 'https://maven.fabricmc.net/'
+        }
+        gradlePluginPortal()
+    }
+}
 
+rootProject.name = 'TCPShield'

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

@@ -0,0 +1,54 @@
+package net.tcpshield.tcpshield.fabric;
+
+import net.fabricmc.api.DedicatedServerModInitializer;
+import net.tcpshield.tcpshield.TCPShieldPacketHandler;
+import net.tcpshield.tcpshield.TCPShieldPlugin;
+import net.tcpshield.tcpshield.fabric.impl.FabricConfig;
+import net.tcpshield.tcpshield.provider.ConfigProvider;
+import net.tcpshield.tcpshield.util.Debugger;
+
+import java.io.IOException;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
+import java.util.logging.Logger;
+
+public class TCPShieldFabric implements DedicatedServerModInitializer, TCPShieldPlugin {
+
+    public static final Logger LOGGER = Logger.getLogger("TCPShield");
+    public static TCPShieldPacketHandler packetHandler;
+    private FabricConfig config;
+    private Debugger debugger;
+
+    @Override
+    public void onInitializeServer() {
+        try {
+            config = new FabricConfig();
+            debugger = Debugger.createDebugger(this);
+            packetHandler = new TCPShieldPacketHandler(this);
+        } catch (NoSuchAlgorithmException | IOException | InvalidKeySpecException exception) {
+            exception.printStackTrace();
+        }
+
+        LOGGER.info("TCPShield has been loaded.");
+    }
+
+    @Override
+    public ConfigProvider getConfigProvider() {
+        return config;
+    }
+
+    @Override
+    public Logger getLogger() {
+        return LOGGER;
+    }
+
+    @Override
+    public TCPShieldPacketHandler getPacketHandler() {
+        return packetHandler;
+    }
+
+    @Override
+    public Debugger getDebugger() {
+        return debugger;
+    }
+}

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

@@ -0,0 +1,124 @@
+package net.tcpshield.tcpshield.fabric.impl;
+
+import net.fabricmc.loader.api.FabricLoader;
+import net.tcpshield.tcpshield.fabric.TCPShieldFabric;
+import net.tcpshield.tcpshield.provider.ConfigProvider;
+import net.tcpshield.tcpshield.util.exception.config.ConfigLoadException;
+import net.tcpshield.tcpshield.util.exception.config.ConfigReloadException;
+import net.tcpshield.tcpshield.util.exception.config.ConfigResetException;
+import net.tcpshield.tcpshield.util.exception.phase.ConfigException;
+
+import java.io.File;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class FabricConfig extends ConfigProvider {
+
+    private final Map<String, String> values = new HashMap<>();
+
+    public FabricConfig() {
+        this.dataFolder = new File(FabricLoader.getInstance().getConfigDir().toString());
+        this.configFile = new File(dataFolder, "config.yml");
+
+        try {
+            reload();
+        } catch (Exception e) {
+            throw new ConfigException(e);
+        }
+    }
+
+    @Override
+    protected void checkNodes(String... nodes) throws ConfigException {
+        for (String node : nodes) {
+            if(!values.containsKey(node))
+                throw new ConfigException("The node \"" + node + "\" does not exist in the config.");
+        }
+    }
+
+    @Override
+    protected void reset() throws ConfigResetException {
+        try {
+            values.clear();
+
+            try {
+                configFile.delete();
+            } catch (Exception ignored) {
+                // Just ignore since it either does not exist, or we can overwrite
+            }
+
+            // 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, configFile.toPath());
+            }
+        } catch (Exception e) {
+            throw new ConfigResetException(e);
+        }
+    }
+
+    @Override
+    protected void load() throws ConfigLoadException {
+        try {
+            values.clear();
+            values.putAll(loadConfig());
+
+            checkNodes("only-allow-proxy-connections", "timestamp-validation", "debug-mode", "enable-geyser-support", "prefer-protocollib");
+
+            this.onlyProxy = Boolean.parseBoolean(values.get("only-allow-proxy-connections"));
+            this.timestampValidationMode = values.get("timestamp-validation");
+            this.doDebug = Boolean.parseBoolean(values.get("debug-mode"));
+            this.geyser = Boolean.parseBoolean(values.get("enable-geyser-support"));
+            this.preferProtocolLib = Boolean.parseBoolean(values.get("prefer-protocollib"));
+        } catch (Exception e) {
+            throw new ConfigLoadException(e);
+        }
+    }
+
+    @Override
+    public void reload() throws ConfigReloadException {
+        try {
+            if(!dataFolder.exists())
+                dataFolder.mkdir();
+
+            if(!configFile.exists())
+                reset();
+
+            try {
+                load();
+            } catch (ConfigLoadException exception) {
+                TCPShieldFabric.LOGGER.warning("Config loading failed, resetting to default config. (This can be ignored if you just switched builds of TCPShield)");
+                reset();
+                reload(); // Redo cycle, possible StackOverFlow, but realistically only happens if reset fails
+            }
+        } catch (Exception e) {
+            throw new ConfigReloadException(e);
+        }
+    }
+
+    private Map<String, String> loadConfig() {
+        Map<String, String> configValues = new HashMap<>();
+
+        try {
+            List<String> strings = Files.readAllLines(configFile.toPath());
+
+            // Rudimentary config parsing
+            for (String line : strings) {
+                String[] entry = line.replace(" ", "").split(":");
+
+                // A config option will only be valid if it is in the format 'a: b'.
+                // Ensure that is the case now.
+                if (entry.length == 2) {
+                    String key = entry[0];
+                    String value = entry[1];
+                    configValues.put(key, value);
+                }
+            }
+        } catch (Exception e) {
+            throw new ConfigException("Couldn't load config at config/config.yml!");
+        }
+
+        return configValues;
+    }
+}

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

@@ -0,0 +1,25 @@
+package net.tcpshield.tcpshield.fabric.impl;
+
+import net.minecraft.network.packet.c2s.handshake.HandshakeC2SPacket;
+import net.tcpshield.tcpshield.fabric.mixin.HandshakeC2SPacketAccessor;
+import net.tcpshield.tcpshield.provider.PacketProvider;
+import net.tcpshield.tcpshield.util.exception.manipulate.PacketManipulationException;
+
+public class FabricPacket implements PacketProvider  {
+
+    private final HandshakeC2SPacket handshake;
+
+    public FabricPacket(HandshakeC2SPacket handshake) {
+        this.handshake = handshake;
+    }
+
+    @Override
+    public String getPayloadString() {
+        return ((HandshakeC2SPacketAccessor) handshake).getAddress();
+    }
+
+    @Override
+    public void setPacketHostname(String hostname) throws PacketManipulationException {
+        // NO OPERATION
+    }
+}

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

@@ -0,0 +1,48 @@
+package net.tcpshield.tcpshield.fabric.impl;
+
+import net.minecraft.network.ClientConnection;
+import net.minecraft.network.packet.c2s.handshake.HandshakeC2SPacket;
+import net.minecraft.text.LiteralText;
+import net.tcpshield.tcpshield.fabric.mixin.ClientConnectionAccessor;
+import net.tcpshield.tcpshield.provider.PlayerProvider;
+
+import java.net.InetSocketAddress;
+
+public class FabricPlayer implements PlayerProvider {
+
+    private final ClientConnection connection;
+    private String ip;
+
+    public FabricPlayer(HandshakeC2SPacket packet, ClientConnection connection) {
+        this.connection = connection;
+        this.ip = ((InetSocketAddress) ((ClientConnectionAccessor) connection).getChannel().remoteAddress()).getAddress().getHostAddress();
+    }
+
+    @Override
+    public String getUUID() {
+        return "unknown";
+    }
+
+    @Override
+    public String getName() {
+        return "unknown";
+    }
+
+    @Override
+    public String getIP() {
+        return ip;
+    }
+
+    @Override
+    public void setIP(InetSocketAddress ip) {
+        // 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 +1,18 @@
+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();
+}

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.fabric.TCPShieldFabric;
+import net.tcpshield.tcpshield.fabric.impl.FabricPacket;
+import net.tcpshield.tcpshield.fabric.impl.FabricPlayer;
+import net.tcpshield.tcpshield.provider.PacketProvider;
+import net.tcpshield.tcpshield.provider.PlayerProvider;
+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) {
+        PacketProvider packet = new FabricPacket(handshake);
+        PlayerProvider player = new FabricPlayer(handshake, connection);
+
+        TCPShieldFabric.packetHandler.handleHandshake(packet, player);
+    }
+}