Edit readme

Better Packet Limiter

.github/FUNDING.yml

@@ -1 +0,0 @@
-ko_fi: nanit

README.md

@@ -5,16 +5,16 @@ The main goal of this project is maximum simplicity with a minimum number of sen
 The limbo is empty; there is no ability to set a schematic building since this is not necessary.
 You can send useful information via chat or boss bar.
 
-No plugins, no logs. The server is fully clear. It is only able keep a lot of players while the main server is down.
+The server is fully clear. It is only able to keep a lot of players while the main server is down.
 
 General features:
 * High performance. The server doesn't save or cache any useless (for limbo) data.
-* Doesn't spawn threads per player. Uses a fixed thread pool.
+* Doesn't spawn threads per player. Use a fixed thread pool.
 * Support for **BungeeCord** and **Velocity** info forwarding.
 * Support for [BungeeGuard](https://www.spigotmc.org/resources/79601/) handshake format.
 * Multiple versions support.
 * Fully configurable.
-* Lightweight. App size around **2MB**.
+* Lightweight. App size around **3MB**.
 
 ![](https://i.imgur.com/sT8p1Gz.png)
 
@@ -35,6 +35,8 @@ Symbol `X` means all minor versions.
 - [x] 1.17.X
 - [x] 1.18.X
 - [x] 1.19.X
+- [x] 1.20.X
+- [x] 1.21
 
 The server **doesn't** support snapshots.
 
@@ -49,14 +51,16 @@ Note that the server also will be closed correctly if you just press `Ctrl+C`.
 
 ### Installation
 
+Required software: JRE 11+
+
 The installation process is simple.
 
 1. Download the latest version of the program [**here**](https://github.com/Nan1t/NanoLimbo/releases).
 2. Put the jar file in the folder you want.
 3. Create a start script as you did for Bukkit or BungeeCord, with a command like this:
    `java -jar NanoLimbo-<version>.jar`
-5. The server will create `settings.yml` file, which is the server configuration.
-6. Configure it as you want and restart the server.
+4. The server will create `settings.yml` file, which is the server configuration. 
+5. Configure it as you want and restart the server.
 
 ### Player info forwarding
 
@@ -74,16 +78,14 @@ Then add your tokens to `tokens` list.
 
 ### Contributing
 
-Feel free to create a pull request if you found some bug or optimization opportunity, or if you want
+Feel free to create a pull request if you find some bug or optimization opportunity, or if you want
 to add some functionality that is suitable for a limbo server and won't significantly load the server.
 
-All PRs should target the `dev` branch to keep the `main` branch stable and clean.
-
 ### Building
 
 Required software:
 
-* JDK 1.8+
+* JDK 11+
 * Gradle 7+ (optional)
 
 To build a minimized jar, go to the project root directory and run in the terminal:

build.gradle

@@ -1,16 +1,17 @@
 plugins {
     id 'java'
     id 'com.github.johnrengelman.shadow' version '7.1.2'
+    id 'com.github.gmazzo.buildconfig' version '3.1.0'
 }
 
-group 'ru.nanit'
-version '1.5.2'
+group 'ua.nanit'
+version '1.8.1'
 
 compileJava {
     options.encoding = "UTF-8"
 }
 
-tasks.withType(JavaCompile) {
+tasks.withType(JavaCompile).configureEach {
     sourceCompatibility = JavaVersion.VERSION_1_8
     targetCompatibility = JavaVersion.VERSION_1_8
 }
@@ -23,10 +24,18 @@ dependencies {
     testImplementation 'org.junit.jupiter:junit-jupiter-api:5.9.3'
     testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.9.3'
 
+    implementation 'ch.qos.logback:logback-classic:1.5.6'
     implementation 'org.spongepowered:configurate-yaml:4.1.2'
-    implementation 'io.netty:netty-all:4.1.93.Final'
+    implementation 'io.netty:netty-all:4.1.101.Final'
     implementation 'net.kyori:adventure-nbt:4.14.0'
     implementation 'com.grack:nanojson:1.8'
+    implementation 'com.google.code.gson:gson:2.10.1'
+}
+
+buildConfig {
+    className("BuildConfig")
+    packageName("ua.nanit.limbo")
+    buildConfigField('String', 'LIMBO_VERSION', "\"${project.version}\"")
 }
 
 shadowJar {
@@ -36,7 +45,9 @@ shadowJar {
         attributes('Main-Class': 'ua.nanit.limbo.NanoLimbo')
     }
 
-    minimize()
+    minimize {
+        exclude(dependency('ch.qos.logback:logback-classic:.*:.*'))
+    }
 }
 
 test {

src/main/java/ua/nanit/limbo/NanoLimbo.java

@@ -18,7 +18,7 @@
 package ua.nanit.limbo;
 
 import ua.nanit.limbo.server.LimboServer;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 public final class NanoLimbo {
 
@@ -26,7 +26,7 @@ public final class NanoLimbo {
         try {
             new LimboServer().start();
         } catch (Exception e) {
-            Logger.error("Cannot start server: ", e);
+            Log.error("Cannot start server: ", e);
         }
     }
 

src/main/java/ua/nanit/limbo/configuration/LimboConfig.java

@@ -71,6 +71,11 @@ public final class LimboConfig {
     private int bossGroupSize;
     private int workerGroupSize;
 
+    private boolean useTrafficLimits;
+    private int maxPacketSize;
+    private double interval;
+    private double maxPacketRate;
+
     public LimboConfig(Path root) {
         this.root = root;
     }
@@ -127,6 +132,11 @@ public final class LimboConfig {
         useEpoll = conf.node("netty", "useEpoll").getBoolean(true);
         bossGroupSize = conf.node("netty", "threads", "bossGroup").getInt(1);
         workerGroupSize = conf.node("netty", "threads", "workerGroup").getInt(4);
+
+        useTrafficLimits = conf.node("traffic", "enable").getBoolean(false);
+        maxPacketSize = conf.node("traffic", "maxPacketSize").getInt(-1);
+        interval = conf.node("traffic", "interval").getDouble(-1.0);
+        maxPacketRate = conf.node("traffic", "maxPacketRate").getDouble(-1.0);
     }
 
     private BufferedReader getReader() throws IOException {
@@ -250,4 +260,20 @@ public final class LimboConfig {
     public int getWorkerGroupSize() {
         return workerGroupSize;
     }
+
+    public boolean isUseTrafficLimits() {
+        return useTrafficLimits;
+    }
+
+    public int getMaxPacketSize() {
+        return maxPacketSize;
+    }
+
+    public double getInterval() {
+        return interval;
+    }
+
+    public double getMaxPacketRate() {
+        return maxPacketRate;
+    }
 }

src/main/java/ua/nanit/limbo/connection/ClientChannelInitializer.java

@@ -21,10 +21,7 @@ import io.netty.channel.Channel;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelPipeline;
 import io.netty.handler.timeout.ReadTimeoutHandler;
-import ua.nanit.limbo.connection.pipeline.PacketDecoder;
-import ua.nanit.limbo.connection.pipeline.PacketEncoder;
-import ua.nanit.limbo.connection.pipeline.VarIntFrameDecoder;
-import ua.nanit.limbo.connection.pipeline.VarIntLengthEncoder;
+import ua.nanit.limbo.connection.pipeline.*;
 import ua.nanit.limbo.server.LimboServer;
 
 import java.util.concurrent.TimeUnit;
@@ -49,6 +46,15 @@ public class ClientChannelInitializer extends ChannelInitializer<Channel> {
                 TimeUnit.MILLISECONDS));
         pipeline.addLast("frame_decoder", new VarIntFrameDecoder());
         pipeline.addLast("frame_encoder", new VarIntLengthEncoder());
+
+        if (server.getConfig().isUseTrafficLimits()) {
+            pipeline.addLast("traffic_limit", new ChannelTrafficHandler(
+                    server.getConfig().getMaxPacketSize(),
+                    server.getConfig().getInterval(),
+                    server.getConfig().getMaxPacketRate()
+            ));
+        }
+
         pipeline.addLast("decoder", decoder);
         pipeline.addLast("encoder", encoder);
         pipeline.addLast("handler", connection);

src/main/java/ua/nanit/limbo/connection/ClientConnection.java

@@ -30,12 +30,13 @@ import ua.nanit.limbo.connection.pipeline.PacketDecoder;
 import ua.nanit.limbo.connection.pipeline.PacketEncoder;
 import ua.nanit.limbo.protocol.ByteMessage;
 import ua.nanit.limbo.protocol.Packet;
+import ua.nanit.limbo.protocol.PacketSnapshot;
 import ua.nanit.limbo.protocol.packets.login.PacketDisconnect;
 import ua.nanit.limbo.protocol.packets.play.PacketKeepAlive;
 import ua.nanit.limbo.protocol.registry.State;
 import ua.nanit.limbo.protocol.registry.Version;
 import ua.nanit.limbo.server.LimboServer;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 import ua.nanit.limbo.util.UuidUtil;
 
 import javax.crypto.Mac;
@@ -94,7 +95,7 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
 
     @Override
     public void channelInactive(@NotNull ChannelHandlerContext ctx) throws Exception {
-        if (state.equals(State.PLAY)) {
+        if (state.equals(State.PLAY) || state.equals(State.CONFIGURATION)) {
             server.getConnections().removeConnection(this);
         }
         super.channelInactive(ctx);
@@ -103,7 +104,7 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
         if (channel.isActive()) {
-            Logger.error("Unhandled exception: ", cause);
+            Log.error("Unhandled exception: ", cause);
         }
     }
 
@@ -114,7 +115,7 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
 
     public void handlePacket(Object packet) {
         if (packet instanceof Packet) {
-            ((Packet)packet).handle(this, server);
+            ((Packet) packet).handle(this, server);
         }
     }
 
@@ -125,9 +126,21 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
         }
 
         sendPacket(PacketSnapshots.PACKET_LOGIN_SUCCESS);
-        updateState(State.PLAY);
+
         server.getConnections().addConnection(this);
 
+        // Preparing for configuration mode
+        if (clientVersion.moreOrEqual(Version.V1_20_2)) {
+            updateEncoderState(State.CONFIGURATION);
+            return;
+        }
+
+        spawnPlayer();
+    }
+
+    public void spawnPlayer() {
+        updateState(State.PLAY);
+
         Runnable sendPlayPackets = () -> {
             writePacket(PacketSnapshots.PACKET_JOIN_GAME);
             writePacket(PacketSnapshots.PACKET_PLAYER_ABILITIES);
@@ -163,6 +176,14 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
             if (PacketSnapshots.PACKET_HEADER_AND_FOOTER != null && clientVersion.moreOrEqual(Version.V1_8))
                 writePacket(PacketSnapshots.PACKET_HEADER_AND_FOOTER);
 
+            if (clientVersion.moreOrEqual(Version.V1_20_3)) {
+                writePacket(PacketSnapshots.PACKET_START_WAITING_CHUNKS);
+
+                for (PacketSnapshot chunk : PacketSnapshots.PACKETS_EMPTY_CHUNKS) {
+                    writePacket(chunk);
+                }
+            }
+
             sendKeepAlive();
         };
 
@@ -173,6 +194,23 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
         }
     }
 
+    public void onLoginAcknowledgedReceived() {
+        updateState(State.CONFIGURATION);
+
+        if (PacketSnapshots.PACKET_PLUGIN_MESSAGE != null)
+            writePacket(PacketSnapshots.PACKET_PLUGIN_MESSAGE);
+
+        if (clientVersion.moreOrEqual(Version.V1_20_5)) {
+            for (PacketSnapshot packet : PacketSnapshots.PACKETS_REGISTRY_DATA) {
+                writePacket(packet);
+            }
+        } else {
+            writePacket(PacketSnapshots.PACKET_REGISTRY_DATA);
+        }
+
+        sendPacket(PacketSnapshots.PACKET_FINISH_CONFIGURATION);
+    }
+
     public void disconnectLogin(String reason) {
         if (isConnected() && state == State.LOGIN) {
             PacketDisconnect disconnect = new PacketDisconnect();
@@ -226,6 +264,10 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
         encoder.updateState(state);
     }
 
+    public void updateEncoderState(State state) {
+        encoder.updateState(state);
+    }
+
     public void updateVersion(Version version) {
         clientVersion = version;
         decoder.updateVersion(version);
@@ -233,7 +275,7 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
     }
 
     public void setAddress(String host) {
-        this.address = new InetSocketAddress(host, ((InetSocketAddress)this.address).getPort());
+        this.address = new InetSocketAddress(host, ((InetSocketAddress) this.address).getPort());
     }
 
     boolean checkBungeeGuardHandshake(String handshake) {
@@ -270,7 +312,7 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
         setAddress(socketAddressHostname);
         gameProfile.setUuid(uuid);
 
-        Logger.debug("Successfully verified BungeeGuard token");
+        Log.debug("Successfully verified BungeeGuard token");
 
         return true;
     }
@@ -294,7 +336,7 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
             byte[] mySignature = mac.doFinal(data);
             if (!MessageDigest.isEqual(signature, mySignature))
                 return false;
-        } catch (InvalidKeyException |java.security.NoSuchAlgorithmException e) {
+        } catch (InvalidKeyException | java.security.NoSuchAlgorithmException e) {
             throw new AssertionError(e);
         }
         int version = buf.readVarInt();

src/main/java/ua/nanit/limbo/connection/PacketHandler.java

@@ -20,6 +20,8 @@ package ua.nanit.limbo.connection;
 import io.netty.buffer.Unpooled;
 import ua.nanit.limbo.LimboConstants;
 import ua.nanit.limbo.protocol.packets.PacketHandshake;
+import ua.nanit.limbo.protocol.packets.configuration.PacketFinishConfiguration;
+import ua.nanit.limbo.protocol.packets.login.PacketLoginAcknowledged;
 import ua.nanit.limbo.protocol.packets.login.PacketLoginPluginRequest;
 import ua.nanit.limbo.protocol.packets.login.PacketLoginPluginResponse;
 import ua.nanit.limbo.protocol.packets.login.PacketLoginStart;
@@ -27,7 +29,7 @@ import ua.nanit.limbo.protocol.packets.status.PacketStatusPing;
 import ua.nanit.limbo.protocol.packets.status.PacketStatusRequest;
 import ua.nanit.limbo.protocol.packets.status.PacketStatusResponse;
 import ua.nanit.limbo.server.LimboServer;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 import ua.nanit.limbo.util.UuidUtil;
 
 import java.util.concurrent.ThreadLocalRandom;
@@ -44,7 +46,7 @@ public class PacketHandler {
         conn.updateVersion(packet.getVersion());
         conn.updateState(packet.getNextState());
 
-        Logger.debug("Pinged from %s [%s]", conn.getAddress(),
+        Log.debug("Pinged from %s [%s]", conn.getAddress(),
                 conn.getClientVersion().toString());
 
         if (server.getConfig().getInfoForwarding().isLegacy()) {
@@ -127,4 +129,12 @@ public class PacketHandler {
         }
     }
 
+    public void handle(ClientConnection conn, PacketLoginAcknowledged packet) {
+        conn.onLoginAcknowledgedReceived();
+    }
+
+    public void handle(ClientConnection conn, PacketFinishConfiguration packet) {
+        conn.spawnPlayer();
+    }
+
 }

src/main/java/ua/nanit/limbo/connection/PacketSnapshots.java

@@ -17,15 +17,24 @@
 
 package ua.nanit.limbo.connection;
 
+import net.kyori.adventure.nbt.BinaryTag;
+import net.kyori.adventure.nbt.CompoundBinaryTag;
+import net.kyori.adventure.nbt.ListBinaryTag;
 import ua.nanit.limbo.LimboConstants;
 import ua.nanit.limbo.protocol.PacketSnapshot;
+import ua.nanit.limbo.protocol.packets.configuration.PacketFinishConfiguration;
+import ua.nanit.limbo.protocol.packets.configuration.PacketRegistryData;
 import ua.nanit.limbo.protocol.packets.login.PacketLoginSuccess;
 import ua.nanit.limbo.protocol.packets.play.*;
 import ua.nanit.limbo.server.LimboServer;
 import ua.nanit.limbo.server.data.Title;
+import ua.nanit.limbo.util.NbtMessageUtil;
 import ua.nanit.limbo.util.UuidUtil;
+import ua.nanit.limbo.world.Dimension;
 
+import java.util.ArrayList;
 import java.util.Collections;
+import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.ThreadLocalRandom;
 
@@ -43,7 +52,7 @@ public final class PacketSnapshots {
     public static PacketSnapshot PACKET_HEADER_AND_FOOTER;
 
     public static PacketSnapshot PACKET_PLAYER_POS_AND_LOOK_LEGACY;
-    // For 1.19 we need to spawn player outside world to avoid stuck in terrain loading
+    // For 1.19 we need to spawn player outside the world to avoid stuck in terrain loading
     public static PacketSnapshot PACKET_PLAYER_POS_AND_LOOK;
 
     public static PacketSnapshot PACKET_TITLE_TITLE;
@@ -54,6 +63,12 @@ public final class PacketSnapshots {
     public static PacketSnapshot PACKET_TITLE_LEGACY_SUBTITLE;
     public static PacketSnapshot PACKET_TITLE_LEGACY_TIMES;
 
+    public static PacketSnapshot PACKET_REGISTRY_DATA;
+    public static List<PacketSnapshot> PACKETS_REGISTRY_DATA;
+    public static PacketSnapshot PACKET_FINISH_CONFIGURATION;
+
+    public static List<PacketSnapshot> PACKETS_EMPTY_CHUNKS;
+    public static PacketSnapshot PACKET_START_WAITING_CHUNKS;
 
     private PacketSnapshots() { }
 
@@ -117,8 +132,8 @@ public final class PacketSnapshots {
 
         if (server.getConfig().isUseHeaderAndFooter()) {
             PacketPlayerListHeader header = new PacketPlayerListHeader();
-            header.setHeader(server.getConfig().getPlayerListHeader());
-            header.setFooter(server.getConfig().getPlayerListFooter());
+            header.setHeader(NbtMessageUtil.create(server.getConfig().getPlayerListHeader()));
+            header.setFooter(NbtMessageUtil.create(server.getConfig().getPlayerListFooter()));
             PACKET_HEADER_AND_FOOTER = PacketSnapshot.of(header);
         }
 
@@ -131,7 +146,7 @@ public final class PacketSnapshots {
 
         if (server.getConfig().isUseJoinMessage()) {
             PacketChatMessage joinMessage = new PacketChatMessage();
-            joinMessage.setJsonData(server.getConfig().getJoinMessage());
+            joinMessage.setMessage(NbtMessageUtil.create(server.getConfig().getJoinMessage()));
             joinMessage.setPosition(PacketChatMessage.PositionLegacy.SYSTEM_MESSAGE);
             joinMessage.setSender(UUID.randomUUID());
             PACKET_JOIN_MESSAGE = PacketSnapshot.of(joinMessage);
@@ -178,5 +193,65 @@ public final class PacketSnapshots {
             PACKET_TITLE_LEGACY_SUBTITLE = PacketSnapshot.of(legacySubtitle);
             PACKET_TITLE_LEGACY_TIMES = PacketSnapshot.of(legacyTimes);
         }
+
+        PacketRegistryData packetRegistryData = new PacketRegistryData();
+        packetRegistryData.setDimensionRegistry(server.getDimensionRegistry());
+
+        PACKET_REGISTRY_DATA = PacketSnapshot.of(packetRegistryData);
+
+        Dimension dimension1_21 = server.getDimensionRegistry().getDimension_1_21();
+        List<PacketSnapshot> packetRegistries = new ArrayList<>();
+        CompoundBinaryTag dimensionTag = dimension1_21.getData();
+        for (String registryType : dimensionTag.keySet()) {
+            CompoundBinaryTag compoundRegistryType = dimensionTag.getCompound(registryType);
+
+            PacketRegistryData registryData = new PacketRegistryData();
+            registryData.setDimensionRegistry(server.getDimensionRegistry());
+
+            ListBinaryTag values = compoundRegistryType.getList("value");
+            registryData.setMetadataWriter((message, version) -> {
+                message.writeString(registryType);
+
+                message.writeVarInt(values.size());
+                for (BinaryTag entry : values) {
+                    CompoundBinaryTag entryTag = (CompoundBinaryTag) entry;
+
+                    String name = entryTag.getString("name");
+                    CompoundBinaryTag element = entryTag.getCompound("element");
+
+                    message.writeString(name);
+                    message.writeBoolean(true);
+                    message.writeNamelessCompoundTag(element);
+                }
+            });
+
+            packetRegistries.add(PacketSnapshot.of(registryData));
+        }
+
+        PACKETS_REGISTRY_DATA = packetRegistries;
+
+        PACKET_FINISH_CONFIGURATION = PacketSnapshot.of(new PacketFinishConfiguration());
+
+        PacketGameEvent packetGameEvent = new PacketGameEvent();
+        packetGameEvent.setType((byte) 13); // Waiting for chunks type
+        packetGameEvent.setValue(0);
+        PACKET_START_WAITING_CHUNKS = PacketSnapshot.of(packetGameEvent);
+
+        int chunkXOffset = (int) 0 >> 4; // Default x position is 0
+        int chunkZOffset = (int) 0 >> 4; // Default z position is 0
+        int chunkEdgeSize = 1; // TODO Make configurable?
+
+        List<PacketSnapshot> emptyChunks = new ArrayList<>();
+        // Make multiple chunks for edges
+        for (int chunkX = chunkXOffset - chunkEdgeSize; chunkX <= chunkXOffset + chunkEdgeSize; ++chunkX) {
+            for (int chunkZ = chunkZOffset - chunkEdgeSize; chunkZ <= chunkZOffset + chunkEdgeSize; ++chunkZ) {
+                PacketEmptyChunk packetEmptyChunk = new PacketEmptyChunk();
+                packetEmptyChunk.setX(chunkX);
+                packetEmptyChunk.setZ(chunkZ);
+
+                emptyChunks.add(PacketSnapshot.of(packetEmptyChunk));
+            }
+        }
+        PACKETS_EMPTY_CHUNKS = emptyChunks;
     }
 }

src/main/java/ua/nanit/limbo/connection/pipeline/ChannelTrafficHandler.java

@@ -0,0 +1,111 @@
+package ua.nanit.limbo.connection.pipeline;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import org.jetbrains.annotations.NotNull;
+import ua.nanit.limbo.server.Log;
+
+import java.util.Arrays;
+
+public class ChannelTrafficHandler extends ChannelInboundHandlerAdapter {
+
+    private final int maxPacketSize;
+    private final double maxPacketRate;
+    private final PacketBucket packetBucket;
+
+    public ChannelTrafficHandler(int maxPacketSize, double interval, double maxPacketRate) {
+        this.maxPacketSize = maxPacketSize;
+        this.maxPacketRate = maxPacketRate;
+        this.packetBucket = (interval > 0.0 && maxPacketRate > 0.0) ? new PacketBucket(interval * 1000.0, 150) : null;
+    }
+
+    @Override
+    public void channelRead(@NotNull ChannelHandlerContext ctx, @NotNull Object msg) throws Exception {
+        if (msg instanceof ByteBuf) {
+            ByteBuf in = (ByteBuf) msg;
+            int bytes = in.readableBytes();
+
+            if (maxPacketSize > 0 && bytes > maxPacketSize) {
+                closeConnection(ctx, "Closed %s due to large packet size (%d bytes)", ctx.channel().remoteAddress(), bytes);
+                return;
+            }
+
+            if (packetBucket != null) {
+                packetBucket.incrementPackets(1);
+                if (packetBucket.getCurrentPacketRate() > maxPacketRate) {
+                    closeConnection(ctx, "Closed %s due to many packets sent (%d in the last %.1f seconds)", ctx.channel().remoteAddress(), packetBucket.sum, (packetBucket.intervalTime / 1000.0));
+                    return;
+                }
+            }
+        }
+
+        super.channelRead(ctx, msg);
+    }
+
+    private void closeConnection(ChannelHandlerContext ctx, String reason, Object... args) {
+        ctx.close();
+        Log.info(reason, args);
+    }
+
+    private static class PacketBucket {
+        private static final double NANOSECONDS_TO_MILLISECONDS = 1.0e-6;
+        private static final int MILLISECONDS_TO_SECONDS = 1000;
+
+        private final double intervalTime;
+        private final double intervalResolution;
+        private final int[] data;
+        private int newestData;
+        private double lastBucketTime;
+        private int sum;
+
+        public PacketBucket(final double intervalTime, final int totalBuckets) {
+            this.intervalTime = intervalTime;
+            this.intervalResolution = intervalTime / totalBuckets;
+            this.data = new int[totalBuckets];
+        }
+
+        public void incrementPackets(final int packets) {
+            double timeMs = System.nanoTime() * NANOSECONDS_TO_MILLISECONDS;
+            double timeDelta = timeMs - this.lastBucketTime;
+
+            if (timeDelta < 0.0) {
+                timeDelta = 0.0;
+            }
+
+            if (timeDelta < this.intervalResolution) {
+                this.data[this.newestData] += packets;
+                this.sum += packets;
+                return;
+            }
+
+            int bucketsToMove = (int)(timeDelta / this.intervalResolution);
+            double nextBucketTime = this.lastBucketTime + bucketsToMove * this.intervalResolution;
+
+            if (bucketsToMove >= this.data.length) {
+                Arrays.fill(this.data, 0);
+                this.data[0] = packets;
+                this.sum = packets;
+                this.newestData = 0;
+                this.lastBucketTime = timeMs;
+                return;
+            }
+
+            for (int i = 1; i < bucketsToMove; ++i) {
+                int index = (this.newestData + i) % this.data.length;
+                this.sum -= this.data[index];
+                this.data[index] = 0;
+            }
+
+            int newestDataIndex = (this.newestData + bucketsToMove) % this.data.length;
+            this.sum += packets - this.data[newestDataIndex];
+            this.data[newestDataIndex] = packets;
+            this.newestData = newestDataIndex;
+            this.lastBucketTime = nextBucketTime;
+        }
+
+        public double getCurrentPacketRate() {
+            return this.sum / (this.intervalTime / MILLISECONDS_TO_SECONDS);
+        }
+    }
+}

src/main/java/ua/nanit/limbo/connection/pipeline/PacketDecoder.java

@@ -24,7 +24,7 @@ import ua.nanit.limbo.protocol.ByteMessage;
 import ua.nanit.limbo.protocol.Packet;
 import ua.nanit.limbo.protocol.registry.State;
 import ua.nanit.limbo.protocol.registry.Version;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 import java.util.List;
 
@@ -47,16 +47,20 @@ public class PacketDecoder extends MessageToMessageDecoder<ByteBuf> {
         Packet packet = mappings.getPacket(packetId);
 
         if (packet != null) {
-            Logger.debug("Received packet %s[0x%s]", packet.toString(), Integer.toHexString(packetId));
+            Log.debug("Received packet %s[0x%s] (%d bytes)", packet.toString(), Integer.toHexString(packetId), msg.readableBytes());
             try {
                 packet.decode(msg, version);
             } catch (Exception e) {
-                Logger.warning("Cannot decode packet 0x%s: %s", Integer.toHexString(packetId), e.getMessage());
+                if (Log.isDebug()) {
+                    Log.warning("Cannot decode packet 0x%s", e, Integer.toHexString(packetId));
+                } else {
+                    Log.warning("Cannot decode packet 0x%s: %s", Integer.toHexString(packetId), e.getMessage());
+                }
             }
 
             ctx.fireChannelRead(packet);
         } else {
-            Logger.debug("Undefined incoming packet: 0x" + Integer.toHexString(packetId));
+            Log.debug("Undefined incoming packet: 0x" + Integer.toHexString(packetId));
         }
     }
 

src/main/java/ua/nanit/limbo/connection/pipeline/PacketEncoder.java

@@ -25,7 +25,7 @@ import ua.nanit.limbo.protocol.Packet;
 import ua.nanit.limbo.protocol.PacketSnapshot;
 import ua.nanit.limbo.protocol.registry.State;
 import ua.nanit.limbo.protocol.registry.Version;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 public class PacketEncoder extends MessageToByteEncoder<Packet> {
 
@@ -51,7 +51,7 @@ public class PacketEncoder extends MessageToByteEncoder<Packet> {
         }
 
         if (packetId == -1) {
-            Logger.warning("Undefined packet class: %s[0x%s]", packet.getClass().getName(), Integer.toHexString(packetId));
+            Log.warning("Undefined packet class: %s[0x%s] (%d bytes)", packet.getClass().getName(), Integer.toHexString(packetId), msg.readableBytes());
             return;
         }
 
@@ -60,11 +60,11 @@ public class PacketEncoder extends MessageToByteEncoder<Packet> {
         try {
             packet.encode(msg, version);
 
-            if (Logger.getLevel() >= Logger.Level.DEBUG.getIndex()) {
-                Logger.debug("Sending %s[0x%s] packet (%d bytes)", packet.toString(), Integer.toHexString(packetId), msg.readableBytes());
+            if (Log.isDebug()) {
+                Log.debug("Sending %s[0x%s] packet (%d bytes)", packet.toString(), Integer.toHexString(packetId), msg.readableBytes());
             }
         } catch (Exception e) {
-            Logger.error("Cannot encode packet 0x%s: %s", Integer.toHexString(packetId), e.getMessage());
+            Log.error("Cannot encode packet 0x%s: %s", Integer.toHexString(packetId), e.getMessage());
         }
     }
 

src/main/java/ua/nanit/limbo/connection/pipeline/VarIntFrameDecoder.java

@@ -20,7 +20,7 @@ package ua.nanit.limbo.connection.pipeline;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageDecoder;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 import java.util.List;
 
@@ -42,18 +42,19 @@ public class VarIntFrameDecoder extends ByteToMessageDecoder {
             int readVarInt = reader.getReadVarInt();
             int bytesRead = reader.getBytesRead();
             if (readVarInt < 0) {
-                Logger.error("[VarIntFrameDecoder] Bad data length");
+                Log.error("[VarIntFrameDecoder] Bad data length");
             } else if (readVarInt == 0) {
                 in.readerIndex(varIntEnd + 1);
             } else {
                 int minimumRead = bytesRead + readVarInt;
+
                 if (in.isReadable(minimumRead)) {
                     out.add(in.retainedSlice(varIntEnd + 1, readVarInt));
                     in.skipBytes(minimumRead);
                 }
             }
         } else if (reader.getResult() == VarIntByteDecoder.DecodeResult.TOO_BIG) {
-            Logger.error("[VarIntFrameDecoder] Too big data");
+            Log.error("[VarIntFrameDecoder] Too big data");
         }
     }
 }

src/main/java/ua/nanit/limbo/protocol/ByteMessage.java

@@ -21,8 +21,8 @@ import io.netty.buffer.*;
 import io.netty.handler.codec.DecoderException;
 import io.netty.handler.codec.EncoderException;
 import io.netty.util.ByteProcessor;
-import net.kyori.adventure.nbt.BinaryTagIO;
-import net.kyori.adventure.nbt.CompoundBinaryTag;
+import net.kyori.adventure.nbt.*;
+import ua.nanit.limbo.protocol.registry.Version;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -73,14 +73,37 @@ public class ByteMessage extends ByteBuf {
     }
 
     public void writeVarInt(int value) {
-        while (true) {
-            if ((value & 0xFFFFFF80) == 0) {
+        // Peel the one and two byte count cases explicitly as they are the most common VarInt sizes
+        // that the proxy will write, to improve inlining.
+        if ((value & (0xFFFFFFFF << 7)) == 0) {
             buf.writeByte(value);
-                return;
+        } else if ((value & (0xFFFFFFFF << 14)) == 0) {
+            int w = (value & 0x7F | 0x80) << 8 | (value >>> 7);
+            buf.writeShort(w);
+        } else {
+            writeVarIntFull(value);
+        }
     }
 
-            buf.writeByte(value & 0x7F | 0x80);
-            value >>>= 7;
+    private void writeVarIntFull(final int value) {
+        // See https://steinborn.me/posts/performance/how-fast-can-you-write-a-varint/
+        if ((value & (0xFFFFFFFF << 7)) == 0) {
+            buf.writeByte(value);
+        } else if ((value & (0xFFFFFFFF << 14)) == 0) {
+            int w = (value & 0x7F | 0x80) << 8 | (value >>> 7);
+            buf.writeShort(w);
+        } else if ((value & (0xFFFFFFFF << 21)) == 0) {
+            int w = (value & 0x7F | 0x80) << 16 | ((value >>> 7) & 0x7F | 0x80) << 8 | (value >>> 14);
+            buf.writeMedium(w);
+        } else if ((value & (0xFFFFFFFF << 28)) == 0) {
+            int w = (value & 0x7F | 0x80) << 24 | (((value >>> 7) & 0x7F | 0x80) << 16)
+                    | ((value >>> 14) & 0x7F | 0x80) << 8 | (value >>> 21);
+            buf.writeInt(w);
+        } else {
+            int w = (value & 0x7F | 0x80) << 24 | ((value >>> 7) & 0x7F | 0x80) << 16
+                    | ((value >>> 14) & 0x7F | 0x80) << 8 | ((value >>> 21) & 0x7F | 0x80);
+            buf.writeInt(w);
+            buf.writeByte(value >>> 28);
         }
     }
 
@@ -193,6 +216,63 @@ public class ByteMessage extends ByteBuf {
         }
     }
 
+    public void writeNamelessCompoundTag(BinaryTag binaryTag) {
+        try (ByteBufOutputStream stream = new ByteBufOutputStream(buf)) {
+            stream.writeByte(binaryTag.type().id());
+
+            // TODO Find a way to improve this...
+            if (binaryTag instanceof CompoundBinaryTag) {
+                CompoundBinaryTag tag = (CompoundBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof ByteBinaryTag) {
+                ByteBinaryTag tag = (ByteBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof ShortBinaryTag) {
+                ShortBinaryTag tag = (ShortBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else  if (binaryTag instanceof IntBinaryTag) {
+                IntBinaryTag tag = (IntBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof LongBinaryTag) {
+                LongBinaryTag tag = (LongBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof DoubleBinaryTag) {
+                DoubleBinaryTag tag = (DoubleBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof StringBinaryTag) {
+                StringBinaryTag tag = (StringBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof ListBinaryTag) {
+                ListBinaryTag tag = (ListBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+            else if (binaryTag instanceof EndBinaryTag) {
+                EndBinaryTag tag = (EndBinaryTag) binaryTag;
+                tag.type().write(tag, stream);
+            }
+
+        }
+        catch (IOException e) {
+            throw new EncoderException("Cannot write NBT CompoundTag");
+        }
+    }
+
+    public void writeNbtMessage(NbtMessage nbtMessage, Version version) {
+        if (version.moreOrEqual(Version.V1_20_3)) {
+            writeNamelessCompoundTag(nbtMessage.getTag());
+        }
+        else {
+            writeString(nbtMessage.getJson());
+        }
+    }
+
     public <E extends Enum<E>> void writeEnumSet(EnumSet<E> enumset, Class<E> oclass) {
         E[] enums = oclass.getEnumConstants();
         BitSet bits = new BitSet(enums.length);

src/main/java/ua/nanit/limbo/protocol/MetadataWriter.java

@@ -0,0 +1,10 @@
+package ua.nanit.limbo.protocol;
+
+import ua.nanit.limbo.protocol.registry.Version;
+
+@FunctionalInterface
+public interface MetadataWriter {
+
+    void writeData(ByteMessage message, Version version);
+
+}

src/main/java/ua/nanit/limbo/protocol/NbtMessage.java

@@ -0,0 +1,30 @@
+package ua.nanit.limbo.protocol;
+
+import net.kyori.adventure.nbt.BinaryTag;
+
+public class NbtMessage {
+
+    private String json;
+    private BinaryTag tag;
+
+    public NbtMessage(String json, BinaryTag tag) {
+        this.json = json;
+        this.tag = tag;
+    }
+
+    public String getJson() {
+        return json;
+    }
+
+    public void setJson(String json) {
+        this.json = json;
+    }
+
+    public BinaryTag getTag() {
+        return tag;
+    }
+
+    public void setTag(BinaryTag tag) {
+        this.tag = tag;
+    }
+}

src/main/java/ua/nanit/limbo/protocol/PacketSnapshot.java

@@ -23,8 +23,8 @@ import java.util.HashMap;
 import java.util.Map;
 
 /**
- * PacketSnapshot encodes packet to byte array for each MC version.
- * Some versions have same snapshot, so there are mappings to avoid data copying
+ * PacketSnapshot encodes a packet to byte array for each MC version.
+ * Some versions have the same snapshot, so there are mappings to avoid data copying
  */
 public class PacketSnapshot implements PacketOut {
 

src/main/java/ua/nanit/limbo/protocol/packets/configuration/PacketFinishConfiguration.java

@@ -0,0 +1,19 @@
+package ua.nanit.limbo.protocol.packets.configuration;
+
+import ua.nanit.limbo.connection.ClientConnection;
+import ua.nanit.limbo.protocol.PacketIn;
+import ua.nanit.limbo.protocol.PacketOut;
+import ua.nanit.limbo.server.LimboServer;
+
+public class PacketFinishConfiguration implements PacketIn, PacketOut {
+
+    @Override
+    public void handle(ClientConnection conn, LimboServer server) {
+        server.getPacketHandler().handle(conn, this);
+    }
+
+    @Override
+    public String toString() {
+        return getClass().getSimpleName();
+    }
+}

src/main/java/ua/nanit/limbo/protocol/packets/configuration/PacketRegistryData.java

@@ -0,0 +1,32 @@
+package ua.nanit.limbo.protocol.packets.configuration;
+
+import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.MetadataWriter;
+import ua.nanit.limbo.protocol.PacketOut;
+import ua.nanit.limbo.protocol.registry.Version;
+import ua.nanit.limbo.world.DimensionRegistry;
+
+public class PacketRegistryData implements PacketOut {
+
+    private DimensionRegistry dimensionRegistry;
+    private MetadataWriter metadataWriter;
+
+    public void setDimensionRegistry(DimensionRegistry dimensionRegistry) {
+        this.dimensionRegistry = dimensionRegistry;
+    }
+
+    public void setMetadataWriter(MetadataWriter metadataWriter) {
+        this.metadataWriter = metadataWriter;
+    }
+
+    @Override
+    public void encode(ByteMessage msg, Version version) {
+        if (metadataWriter != null) {
+            if (version.moreOrEqual(Version.V1_20_5)) {
+                metadataWriter.writeData(msg, version);
+                return;
+            }
+        }
+        msg.writeNamelessCompoundTag(dimensionRegistry.getCodec_1_20());
+    }
+}

src/main/java/ua/nanit/limbo/protocol/packets/login/PacketLoginAcknowledged.java

@@ -0,0 +1,19 @@
+package ua.nanit.limbo.protocol.packets.login;
+
+import ua.nanit.limbo.connection.ClientConnection;
+import ua.nanit.limbo.protocol.PacketIn;
+import ua.nanit.limbo.protocol.PacketOut;
+import ua.nanit.limbo.server.LimboServer;
+
+public class PacketLoginAcknowledged implements PacketIn, PacketOut {
+
+    @Override
+    public void handle(ClientConnection conn, LimboServer server) {
+        server.getPacketHandler().handle(conn, this);
+    }
+
+    @Override
+    public String toString() {
+        return getClass().getSimpleName();
+    }
+}

src/main/java/ua/nanit/limbo/protocol/packets/login/PacketLoginSuccess.java

@@ -49,6 +49,9 @@ public class PacketLoginSuccess implements PacketOut {
         if (version.moreOrEqual(Version.V1_19)) {
             msg.writeVarInt(0);
         }
+        if (version.moreOrEqual(Version.V1_20_5)) {
+            msg.writeBoolean(true);
+        }
     }
 
     @Override

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketBossBar.java

@@ -49,7 +49,7 @@ public class PacketBossBar implements PacketOut {
     public void encode(ByteMessage msg, Version version) {
         msg.writeUuid(uuid);
         msg.writeVarInt(0); // Create bossbar
-        msg.writeString(bossBar.getText());
+        msg.writeNbtMessage(bossBar.getText(), version);
         msg.writeFloat(bossBar.getHealth());
         msg.writeVarInt(bossBar.getColor().getIndex());
         msg.writeVarInt(bossBar.getDivision().getIndex());

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketChatMessage.java

@@ -18,6 +18,7 @@
 package ua.nanit.limbo.protocol.packets.play;
 
 import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.NbtMessage;
 import ua.nanit.limbo.protocol.PacketOut;
 import ua.nanit.limbo.protocol.registry.Version;
 
@@ -25,12 +26,12 @@ import java.util.UUID;
 
 public class PacketChatMessage implements PacketOut {
 
-    private String jsonData;
+    private NbtMessage message;
     private PositionLegacy position;
     private UUID sender;
 
-    public void setJsonData(String jsonData) {
-        this.jsonData = jsonData;
+    public void setMessage(NbtMessage message) {
+        this.message = message;
     }
 
     public void setPosition(PositionLegacy position) {
@@ -43,7 +44,7 @@ public class PacketChatMessage implements PacketOut {
 
     @Override
     public void encode(ByteMessage msg, Version version) {
-        msg.writeString(jsonData);
+        msg.writeNbtMessage(message, version);
         if (version.moreOrEqual(Version.V1_19_1)) {
             msg.writeBoolean(position.index == PositionLegacy.ACTION_BAR.index);
         } else if (version.moreOrEqual(Version.V1_19)) {

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketEmptyChunk.java

@@ -0,0 +1,47 @@
+package ua.nanit.limbo.protocol.packets.play;
+
+import net.kyori.adventure.nbt.CompoundBinaryTag;
+import net.kyori.adventure.nbt.LongArrayBinaryTag;
+import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.PacketOut;
+import ua.nanit.limbo.protocol.registry.Version;
+
+public class PacketEmptyChunk implements PacketOut {
+
+    private int x;
+    private int z;
+
+    public void setX(int x) {
+        this.x = x;
+    }
+
+    public void setZ(int z) {
+        this.z = z;
+    }
+
+    @Override
+    public void encode(ByteMessage msg, Version version) {
+        msg.writeInt(x);
+        msg.writeInt(z);
+
+        LongArrayBinaryTag longArrayTag = LongArrayBinaryTag.longArrayBinaryTag(new long[37]);
+        CompoundBinaryTag tag = CompoundBinaryTag.builder()
+                .put("MOTION_BLOCKING", longArrayTag).build();
+        CompoundBinaryTag rootTag = CompoundBinaryTag.builder()
+                .put("root", tag).build();
+        msg.writeNamelessCompoundTag(rootTag);
+
+        byte[] sectionData = new byte[]{0, 0, 0, 0, 0, 0, 1, 0};
+        msg.writeVarInt(sectionData.length * 16);
+        for (int i = 0; i < 16; i++) {
+            msg.writeBytes(sectionData);
+        }
+
+        msg.writeVarInt(0);
+
+        byte[] lightData = new byte[]{1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 3, -1, -1, 0, 0};
+        msg.ensureWritable(lightData.length);
+        msg.writeBytes(lightData, 1, lightData.length - 1);
+    }
+    
+}

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketGameEvent.java

@@ -0,0 +1,25 @@
+package ua.nanit.limbo.protocol.packets.play;
+
+import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.PacketOut;
+import ua.nanit.limbo.protocol.registry.Version;
+
+public class PacketGameEvent implements PacketOut {
+
+    private byte type;
+    private float value;
+
+    public void setType(byte type) {
+        this.type = type;
+    }
+
+    public void setValue(float value) {
+        this.value = value;
+    }
+
+    @Override
+    public void encode(ByteMessage msg, Version version) {
+        msg.writeByte(type);
+        msg.writeFloat(value);
+    }
+}

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketJoinGame.java

@@ -38,6 +38,8 @@ public class PacketJoinGame implements PacketOut {
     private boolean enableRespawnScreen;
     private boolean isDebug;
     private boolean isFlat;
+    private boolean limitedCrafting;
+    private boolean secureProfile;
 
     public void setEntityId(int entityId) {
         this.entityId = entityId;
@@ -95,6 +97,14 @@ public class PacketJoinGame implements PacketOut {
         isFlat = flat;
     }
 
+    public void setLimitedCrafting(boolean limitedCrafting) {
+        this.limitedCrafting = limitedCrafting;
+    }
+
+    public void setSecureProfile(boolean secureProfile) {
+        this.secureProfile = secureProfile;
+    }
+
     @Override
     public void encode(ByteMessage msg, Version version) {
         msg.writeInt(entityId);
@@ -230,7 +240,7 @@ public class PacketJoinGame implements PacketOut {
             msg.writeBoolean(false);
         }
 
-        if (version.moreOrEqual(Version.V1_20)) {
+        if (version.equals(Version.V1_20)) {
             msg.writeBoolean(isHardcore);
             msg.writeByte(gameMode);
             msg.writeByte(previousGameMode);
@@ -249,6 +259,47 @@ public class PacketJoinGame implements PacketOut {
             msg.writeBoolean(false);
             msg.writeVarInt(0);
         }
+
+        if (version.fromTo(Version.V1_20_2, Version.V1_20_3)) {
+            msg.writeBoolean(isHardcore);
+            msg.writeStringsArray(worldNames);
+            msg.writeVarInt(maxPlayers);
+            msg.writeVarInt(viewDistance);
+            msg.writeVarInt(viewDistance); // Simulation Distance
+            msg.writeBoolean(reducedDebugInfo);
+            msg.writeBoolean(enableRespawnScreen);
+            msg.writeBoolean(limitedCrafting);
+            msg.writeString(worldName);
+            msg.writeString(worldName);
+            msg.writeLong(hashedSeed);
+            msg.writeByte(gameMode);
+            msg.writeByte(previousGameMode);
+            msg.writeBoolean(isDebug);
+            msg.writeBoolean(isFlat);
+            msg.writeBoolean(false);
+            msg.writeVarInt(0);
+        }
+
+        if (version.moreOrEqual(Version.V1_20_5)) {
+            msg.writeBoolean(isHardcore);
+            msg.writeStringsArray(worldNames);
+            msg.writeVarInt(maxPlayers);
+            msg.writeVarInt(viewDistance);
+            msg.writeVarInt(viewDistance); // Simulation Distance
+            msg.writeBoolean(reducedDebugInfo);
+            msg.writeBoolean(enableRespawnScreen);
+            msg.writeBoolean(limitedCrafting);
+            msg.writeVarInt(dimensionRegistry.getDimension_1_20_5().getId());
+            msg.writeString(worldName);
+            msg.writeLong(hashedSeed);
+            msg.writeByte(gameMode);
+            msg.writeByte(previousGameMode);
+            msg.writeBoolean(isDebug);
+            msg.writeBoolean(isFlat);
+            msg.writeBoolean(false);
+            msg.writeVarInt(0);
+            msg.writeBoolean(secureProfile);
+        }
     }
 
 }

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketPlayerListHeader.java

@@ -18,25 +18,26 @@
 package ua.nanit.limbo.protocol.packets.play;
 
 import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.NbtMessage;
 import ua.nanit.limbo.protocol.PacketOut;
 import ua.nanit.limbo.protocol.registry.Version;
 
 public class PacketPlayerListHeader implements PacketOut {
 
-    private String header;
-    private String footer;
+    private NbtMessage header;
+    private NbtMessage footer;
 
-    public void setHeader(String header) {
+    public void setHeader(NbtMessage header) {
         this.header = header;
     }
 
-    public void setFooter(String footer) {
+    public void setFooter(NbtMessage footer) {
         this.footer = footer;
     }
 
     @Override
     public void encode(ByteMessage msg, Version version) {
-        msg.writeString(header);
-        msg.writeString(footer);
+        msg.writeNbtMessage(header, version);
+        msg.writeNbtMessage(footer, version);
     }
 }

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketPluginMessage.java

@@ -39,4 +39,5 @@ public class PacketPluginMessage implements PacketOut {
         msg.writeString(channel);
         msg.writeString(message);
     }
+
 }

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketTitleSetSubTitle.java

@@ -18,20 +18,21 @@
 package ua.nanit.limbo.protocol.packets.play;
 
 import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.NbtMessage;
 import ua.nanit.limbo.protocol.PacketOut;
 import ua.nanit.limbo.protocol.registry.Version;
 
 public class PacketTitleSetSubTitle implements PacketOut {
 
-    private String subtitle;
+    private NbtMessage subtitle;
 
-    public void setSubtitle(String subtitle) {
+    public void setSubtitle(NbtMessage subtitle) {
         this.subtitle = subtitle;
     }
 
     @Override
     public void encode(ByteMessage msg, Version version) {
-        msg.writeString(subtitle);
+        msg.writeNbtMessage(subtitle, version);
     }
 
 }

src/main/java/ua/nanit/limbo/protocol/packets/play/PacketTitleSetTitle.java

@@ -18,20 +18,21 @@
 package ua.nanit.limbo.protocol.packets.play;
 
 import ua.nanit.limbo.protocol.ByteMessage;
+import ua.nanit.limbo.protocol.NbtMessage;
 import ua.nanit.limbo.protocol.PacketOut;
 import ua.nanit.limbo.protocol.registry.Version;
 
 public class PacketTitleSetTitle implements PacketOut {
 
-    private String title;
+    private NbtMessage title;
 
-    public void setTitle(String title) {
+    public void setTitle(NbtMessage title) {
         this.title = title;
     }
 
     @Override
     public void encode(ByteMessage msg, Version version) {
-        msg.writeString(title);
+        msg.writeNbtMessage(title, version);
     }
 
 }

src/main/java/ua/nanit/limbo/protocol/registry/State.java

@@ -21,6 +21,7 @@ import ua.nanit.limbo.protocol.Packet;
 import ua.nanit.limbo.protocol.packets.PacketHandshake;
 import ua.nanit.limbo.protocol.packets.login.*;
 import ua.nanit.limbo.protocol.packets.play.*;
+import ua.nanit.limbo.protocol.packets.configuration.*;
 import ua.nanit.limbo.protocol.packets.status.PacketStatusPing;
 import ua.nanit.limbo.protocol.packets.status.PacketStatusRequest;
 import ua.nanit.limbo.protocol.packets.status.PacketStatusResponse;
@@ -63,6 +64,10 @@ public enum State {
             serverBound.register(PacketLoginPluginResponse::new,
                     map(0x02, Version.getMin(), Version.getMax())
             );
+            serverBound.register(
+                    PacketLoginAcknowledged::new,
+                    map(0x03, V1_20_2, Version.getMax())
+            );
             clientBound.register(PacketDisconnect::new,
                     map(0x00, Version.getMin(), Version.getMax())
             );
@@ -74,7 +79,52 @@ public enum State {
             );
         }
     },
-    PLAY(3) {
+    CONFIGURATION(3) {
+        {
+            clientBound.register(
+                    PacketPluginMessage::new,
+                    map(0x00, V1_20_2, V1_20_3),
+                    map(0x01, V1_20_5, V1_21)
+            );
+            clientBound.register(
+                    PacketDisconnect::new,
+                    map(0x01, V1_20_2, V1_20_3),
+                    map(0x02, V1_20_5, V1_21)
+            );
+            clientBound.register(
+                    PacketFinishConfiguration::new,
+                    map(0x02, V1_20_2, V1_20_3),
+                    map(0x03, V1_20_5, V1_21)
+            );
+            clientBound.register(
+                    PacketKeepAlive::new,
+                    map(0x03, V1_20_2, V1_20_3),
+                    map(0x04, V1_20_5, V1_21)
+            );
+            clientBound.register(
+                    PacketRegistryData::new,
+                    map(0x05, V1_20_2, V1_20_3),
+                    map(0x07, V1_20_5, V1_21)
+            );
+
+            serverBound.register(
+                    PacketPluginMessage::new,
+                    map(0x01, V1_20_2, V1_20_3),
+                    map(0x02, V1_20_2, V1_21)
+            );
+            serverBound.register(
+                    PacketFinishConfiguration::new,
+                    map(0x02, V1_20_2, V1_20_3),
+                    map(0x03, V1_20_5, V1_21)
+            );
+            serverBound.register(
+                    PacketKeepAlive::new,
+                    map(0x03, V1_20_2, V1_20_3),
+                    map(0x04, V1_20_5, V1_21)
+            );
+        }
+    },
+    PLAY(4) {
         {
             serverBound.register(PacketKeepAlive::new,
                     map(0x00, V1_7_2, V1_8),
@@ -88,7 +138,10 @@ public enum State {
                     map(0x11, V1_19, V1_19),
                     map(0x12, V1_19_1, V1_19_1),
                     map(0x11, V1_19_3, V1_19_3),
-                    map(0x12, V1_19_4, V1_20)
+                    map(0x12, V1_19_4, V1_20),
+                    map(0x14, V1_20_2, V1_20_2),
+                    map(0x15, V1_20_3, V1_20_3),
+                    map(0x18, V1_20_5, V1_21)
             );
 
             clientBound.register(PacketDeclareCommands::new,
@@ -99,7 +152,8 @@ public enum State {
                     map(0x12, V1_17, V1_18_2),
                     map(0x0F, V1_19, V1_19_1),
                     map(0x0E, V1_19_3, V1_19_3),
-                    map(0x10, V1_19_4, V1_20)
+                    map(0x10, V1_19_4, V1_20),
+                    map(0x11, V1_20_2, V1_21)
             );
             clientBound.register(PacketJoinGame::new,
                     map(0x01, V1_7_2, V1_8),
@@ -112,7 +166,9 @@ public enum State {
                     map(0x23, V1_19, V1_19),
                     map(0x25, V1_19_1, V1_19_1),
                     map(0x24, V1_19_3, V1_19_3),
-                    map(0x28, V1_19_4, V1_20)
+                    map(0x28, V1_19_4, V1_20),
+                    map(0x29, V1_20_2, V1_20_3),
+                    map(0x2B, V1_20_5, V1_21)
             );
             clientBound.register(PacketPluginMessage::new,
                     map(0x19, V1_13, V1_13_2),
@@ -124,7 +180,9 @@ public enum State {
                     map(0x15, V1_19, V1_19),
                     map(0x16, V1_19_1, V1_19_1),
                     map(0x15, V1_19_3, V1_19_3),
-                    map(0x17, V1_19_4, V1_20)
+                    map(0x17, V1_19_4, V1_20),
+                    map(0x18, V1_20_2, V1_20_3),
+                    map(0x19, V1_20_5, V1_21)
             );
             clientBound.register(PacketPlayerAbilities::new,
                     map(0x39, V1_7_2, V1_8),
@@ -139,7 +197,9 @@ public enum State {
                     map(0x2F, V1_19, V1_19),
                     map(0x31, V1_19_1, V1_19_1),
                     map(0x30, V1_19_3, V1_19_3),
-                    map(0x34, V1_19_4, V1_20)
+                    map(0x34, V1_19_4, V1_20),
+                    map(0x36, V1_20_2, V1_20_3),
+                    map(0x38, V1_20_5, V1_21)
             );
             clientBound.register(PacketPlayerPositionAndLook::new,
                     map(0x08, V1_7_2, V1_8),
@@ -154,7 +214,9 @@ public enum State {
                     map(0x36, V1_19, V1_19),
                     map(0x39, V1_19_1, V1_19_1),
                     map(0x38, V1_19_3, V1_19_3),
-                    map(0x3C, V1_19_4, V1_20)
+                    map(0x3C, V1_19_4, V1_20),
+                    map(0x3E, V1_20_2, V1_20_3),
+                    map(0x40, V1_20_5, V1_21)
             );
             clientBound.register(PacketKeepAlive::new,
                     map(0x00, V1_7_2, V1_8),
@@ -168,7 +230,9 @@ public enum State {
                     map(0x1E, V1_19, V1_19),
                     map(0x20, V1_19_1, V1_19_1),
                     map(0x1F, V1_19_3, V1_19_3),
-                    map(0x23, V1_19_4, V1_20)
+                    map(0x23, V1_19_4, V1_20),
+                    map(0x24, V1_20_2, V1_20_3),
+                    map(0x26, V1_20_5, V1_21)
             );
             clientBound.register(PacketChatMessage::new,
                     map(0x02, V1_7_2, V1_8),
@@ -180,7 +244,10 @@ public enum State {
                     map(0x5F, V1_19, V1_19),
                     map(0x62, V1_19_1, V1_19_1),
                     map(0x60, V1_19_3, V1_19_3),
-                    map(0x64, V1_19_4, V1_20)
+                    map(0x64, V1_19_4, V1_20),
+                    map(0x67, V1_20_2, V1_20_2),
+                    map(0x69, V1_20_3, V1_20_3),
+                    map(0x6C, V1_20_5, V1_21)
             );
             clientBound.register(PacketBossBar::new,
                     map(0x0C, V1_9, V1_14_4),
@@ -188,7 +255,8 @@ public enum State {
                     map(0x0C, V1_16, V1_16_4),
                     map(0x0D, V1_17, V1_18_2),
                     map(0x0A, V1_19, V1_19_3),
-                    map(0x0B, V1_19_4, V1_20)
+                    map(0x0B, V1_19_4, V1_20),
+                    map(0x0A, V1_20_2, V1_21)
             );
             clientBound.register(PacketPlayerInfo::new,
                     map(0x38, V1_7_2, V1_8),
@@ -203,7 +271,9 @@ public enum State {
                     map(0x34, V1_19, V1_19),
                     map(0x37, V1_19_1, V1_19_1),
                     map(0x36, V1_19_3, V1_19_3),
-                    map(0x3A, V1_19_4, V1_20)
+                    map(0x3A, V1_19_4, V1_20),
+                    map(0x3C, V1_20_2, V1_20_3),
+                    map(0x3E, V1_20_5, V1_21)
             );
             clientBound.register(PacketTitleLegacy::new,
                     map(0x45, V1_8, V1_11_1),
@@ -219,21 +289,30 @@ public enum State {
                     map(0x5A, V1_18, V1_19),
                     map(0x5D, V1_19_1, V1_19_1),
                     map(0x5B, V1_19_3, V1_19_3),
-                    map(0x5F, V1_19_4, V1_20)
+                    map(0x5F, V1_19_4, V1_20),
+                    map(0x61, V1_20_2, V1_20_2),
+                    map(0x63, V1_20_3, V1_20_3),
+                    map(0x65, V1_20_5, V1_21)
             );
             clientBound.register(PacketTitleSetSubTitle::new,
                     map(0x57, V1_17, V1_17_1),
                     map(0x58, V1_18, V1_19),
                     map(0x5B, V1_19_1, V1_19_1),
                     map(0x59, V1_19_3, V1_19_3),
-                    map(0x5D, V1_19_4, V1_20)
+                    map(0x5D, V1_19_4, V1_20),
+                    map(0x5F, V1_20_2, V1_20_2),
+                    map(0x61, V1_20_3, V1_20_3),
+                    map(0x63, V1_20_5, V1_21)
             );
             clientBound.register(PacketTitleTimes::new,
                     map(0x5A, V1_17, V1_17_1),
                     map(0x5B, V1_18, V1_19),
                     map(0x5E, V1_19_1, V1_19_1),
                     map(0x5C, V1_19_3, V1_19_3),
-                    map(0x60, V1_19_4, V1_20)
+                    map(0x60, V1_19_4, V1_20),
+                    map(0x62, V1_20_2, V1_20_2),
+                    map(0x64, V1_20_3, V1_20_3),
+                    map(0x66, V1_20_5, V1_21)
             );
             clientBound.register(PacketPlayerListHeader::new,
                     map(0x47, V1_8, V1_8),
@@ -250,11 +329,25 @@ public enum State {
                     map(0x60, V1_19, V1_19),
                     map(0x63, V1_19_1, V1_19_1),
                     map(0x61, V1_19_3, V1_19_3),
-                    map(0x65, V1_19_4, V1_20)
+                    map(0x65, V1_19_4, V1_20),
+                    map(0x68, V1_20_2, V1_20_2),
+                    map(0x6A, V1_20_3, V1_20_3),
+                    map(0x6D, V1_20_5, V1_21)
             );
             clientBound.register(PacketSpawnPosition::new,
                     map(0x4C, V1_19_3, V1_19_3),
-                    map(0x50, V1_19_4, V1_20)
+                    map(0x50, V1_19_4, V1_20),
+                    map(0x52, V1_20_2, V1_20_2),
+                    map(0x54, V1_20_3, V1_20_3),
+                    map(0x56, V1_20_5, V1_21)
+            );
+            clientBound.register(PacketGameEvent::new,
+                    map(0x20, V1_20_3, V1_20_3),
+                    map(0x22, V1_20_5, V1_21)
+            );
+            clientBound.register(PacketEmptyChunk::new,
+                    map(0x25, V1_20_3, V1_20_3),
+                    map(0x27, V1_20_5, V1_21)
             );
         }
     };

src/main/java/ua/nanit/limbo/protocol/registry/Version.java

@@ -68,7 +68,13 @@ public enum Version {
     // 1.19.2 has same protocol number
     V1_19_3(761),
     V1_19_4(762),
-    V1_20(763);
+    V1_20(763),
+    // 1.20.1 has same protocol number
+    V1_20_2(764),
+    V1_20_3(765),
+    V1_20_5(766),
+    // 1.20.6 has same protocol number
+    V1_21(767);
 
     private static final Map<Integer, Version> VERSION_MAP;
     private static final Version MAX;

src/main/java/ua/nanit/limbo/server/CommandManager.java

@@ -1,9 +1,6 @@
 package ua.nanit.limbo.server;
 
-import ua.nanit.limbo.server.commands.CmdConn;
-import ua.nanit.limbo.server.commands.CmdHelp;
-import ua.nanit.limbo.server.commands.CmdMem;
-import ua.nanit.limbo.server.commands.CmdStop;
+import ua.nanit.limbo.server.commands.*;
 
 import java.util.*;
 
@@ -19,8 +16,10 @@ public final class CommandManager extends Thread {
         return commands.get(name.toLowerCase());
     }
 
-    public void register(String name, Command cmd) {
-        commands.put(name.toLowerCase(), cmd);
+    public void register(Command cmd, String... aliases) {
+        for (String alias : aliases) {
+            commands.put(alias.toLowerCase(), cmd);
+        }
     }
 
     @Override
@@ -41,19 +40,20 @@ public final class CommandManager extends Thread {
                 try {
                     handler.execute();
                 } catch (Throwable t) {
-                    Logger.error("Cannot execute command:", t);
+                    Log.error("Cannot execute command:", t);
                 }
                 continue;
             }
 
-            Logger.info("Unknown command. Type \"help\" to get commands list");
+            Log.info("Unknown command. Type \"help\" to get commands list");
         }
     }
 
     public void registerAll(LimboServer server) {
-        register("help", new CmdHelp(server));
-        register("conn", new CmdConn(server));
-        register("mem", new CmdMem());
-        register("stop", new CmdStop());
+        register(new CmdHelp(server), "help");
+        register(new CmdConn(server), "conn");
+        register(new CmdMem(), "mem");
+        register(new CmdStop(), "stop");
+        register(new CmdVersion(), "version", "ver");
     }
 }

src/main/java/ua/nanit/limbo/server/Connections.java

@@ -43,12 +43,12 @@ public final class Connections {
 
     public void addConnection(ClientConnection connection) {
         connections.put(connection.getUuid(), connection);
-        Logger.info("Player %s connected (%s) [%s]", connection.getUsername(),
+        Log.info("Player %s connected (%s) [%s]", connection.getUsername(),
                 connection.getAddress(), connection.getClientVersion());
     }
 
     public void removeConnection(ClientConnection connection) {
         connections.remove(connection.getUuid());
-        Logger.info("Player %s disconnected", connection.getUsername());
+        Log.info("Player %s disconnected", connection.getUsername());
     }
 }

src/main/java/ua/nanit/limbo/server/LimboServer.java

@@ -72,13 +72,14 @@ public final class LimboServer {
     }
 
     public void start() throws Exception {
-        Logger.info("Starting server...");
-
-        ResourceLeakDetector.setLevel(ResourceLeakDetector.Level.DISABLED);
-
         config = new LimboConfig(Paths.get("./"));
         config.load();
 
+        Log.setLevel(config.getDebugLevel());
+        Log.info("Starting server...");
+
+        ResourceLeakDetector.setLevel(ResourceLeakDetector.Level.DISABLED);
+
         packetHandler = new PacketHandler(this);
         dimensionRegistry = new DimensionRegistry(this);
         dimensionRegistry.load(config.getDimensionType());
@@ -92,9 +93,7 @@ public final class LimboServer {
 
         Runtime.getRuntime().addShutdownHook(new Thread(this::stop, "NanoLimbo shutdown thread"));
 
-        Logger.info("Server started on %s", config.getAddress());
-
-        Logger.setLevel(config.getDebugLevel());
+        Log.info("Server started on %s", config.getAddress());
 
         commandManager = new CommandManager();
         commandManager.registerAll(this);
@@ -110,12 +109,12 @@ public final class LimboServer {
             bossGroup = new EpollEventLoopGroup(config.getBossGroupSize());
             workerGroup = new EpollEventLoopGroup(config.getWorkerGroupSize());
             channelClass = EpollServerSocketChannel.class;
-            Logger.debug("Using Epoll transport type");
+            Log.debug("Using Epoll transport type");
         } else {
             bossGroup = new NioEventLoopGroup(config.getBossGroupSize());
             workerGroup = new NioEventLoopGroup(config.getWorkerGroupSize());
             channelClass = NioServerSocketChannel.class;
-            Logger.debug("Using Java NIO transport type");
+            Log.debug("Using Java NIO transport type");
         }
 
         new ServerBootstrap()
@@ -132,7 +131,7 @@ public final class LimboServer {
     }
 
     private void stop() {
-        Logger.info("Stopping server...");
+        Log.info("Stopping server...");
 
         if (keepAliveTask != null) {
             keepAliveTask.cancel(true);
@@ -146,7 +145,7 @@ public final class LimboServer {
             workerGroup.shutdownGracefully();
         }
 
-        Logger.info("Server stopped, Goodbye!");
+        Log.info("Server stopped, Goodbye!");
     }
 
 }

src/main/java/ua/nanit/limbo/server/Log.java

@@ -17,61 +17,71 @@
 
 package ua.nanit.limbo.server;
 
-import java.time.LocalTime;
-import java.time.format.DateTimeFormatter;
+import ch.qos.logback.classic.Logger;
+import org.slf4j.LoggerFactory;
 
-public final class Logger {
+public final class Log {
 
-    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("hh:mm:ss");
+    private static final Logger LOGGER = (Logger) LoggerFactory.getLogger("Limbo");
     private static int debugLevel = Level.INFO.getIndex();
 
-    private Logger() {}
-
-    public static int getLevel() {
-        return debugLevel;
-    }
+    private Log() {}
 
     public static void info(Object msg, Object... args) {
-        print(Level.INFO, msg, null, args);
+        LOGGER.info(String.format(msg.toString(), args));
     }
 
     public static void debug(Object msg, Object... args) {
-        print(Level.DEBUG, msg, null, args);
+        LOGGER.debug(String.format(msg.toString(), args));
     }
 
     public static void warning(Object msg, Object... args) {
-        print(Level.WARNING, msg, null, args);
+        LOGGER.warn(String.format(msg.toString(), args));
     }
 
     public static void warning(Object msg, Throwable t, Object... args) {
-        print(Level.WARNING, msg, t, args);
+        LOGGER.warn(String.format(msg.toString(), args), t);
     }
 
     public static void error(Object msg, Object... args) {
-        print(Level.ERROR, msg, null, args);
+        LOGGER.error(msg.toString(), args);
     }
 
     public static void error(Object msg, Throwable t, Object... args) {
-        print(Level.ERROR, msg, t, args);
+        LOGGER.error(String.format(msg.toString(), args), t);
     }
 
-    public static void print(Level level, Object msg, Throwable t, Object... args) {
-        if (debugLevel >= level.getIndex()) {
-            System.out.printf("%s: %s%n", getPrefix(level), String.format(msg.toString(), args));
-            if (t != null) t.printStackTrace();
-        }
-    }
-
-    private static String getPrefix(Level level) {
-        return String.format("[%s] [%s]", getTime(), level.getDisplay());
-    }
-
-    private static String getTime() {
-        return LocalTime.now().format(FORMATTER);
+    public static boolean isDebug() {
+        return debugLevel >= Level.DEBUG.getIndex();
     }
 
     static void setLevel(int level) {
         debugLevel = level;
+
+        Logger logback = getRootLogger();
+
+        if (logback != null) {
+            logback.setLevel(convertLevel(level));
+        }
+    }
+
+    private static Logger getRootLogger() {
+        return (Logger) LoggerFactory.getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
+    }
+
+    private static ch.qos.logback.classic.Level convertLevel(int level) {
+        switch (level) {
+            case 0:
+                return ch.qos.logback.classic.Level.ERROR;
+            case 1:
+                return ch.qos.logback.classic.Level.WARN;
+            case 2:
+                return ch.qos.logback.classic.Level.INFO;
+            case 3:
+                return ch.qos.logback.classic.Level.DEBUG;
+            default:
+                throw new IllegalStateException("Undefined log level: " + level);
+        }
     }
 
     public enum Level {

src/main/java/ua/nanit/limbo/server/commands/CmdConn.java

@@ -2,7 +2,7 @@ package ua.nanit.limbo.server.commands;
 
 import ua.nanit.limbo.server.Command;
 import ua.nanit.limbo.server.LimboServer;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 public class CmdConn implements Command {
 
@@ -14,7 +14,7 @@ public class CmdConn implements Command {
 
     @Override
     public void execute() {
-        Logger.info("Connections: %d", server.getConnections().getCount());
+        Log.info("Connections: %d", server.getConnections().getCount());
     }
 
     @Override

src/main/java/ua/nanit/limbo/server/commands/CmdHelp.java

@@ -2,7 +2,7 @@ package ua.nanit.limbo.server.commands;
 
 import ua.nanit.limbo.server.Command;
 import ua.nanit.limbo.server.LimboServer;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 import java.util.Map;
 
@@ -18,10 +18,10 @@ public class CmdHelp implements Command {
     public void execute() {
         Map<String, Command> commands = server.getCommandManager().getCommands();
 
-        Logger.info("Available commands:");
+        Log.info("Available commands:");
 
         for (Map.Entry<String, Command> entry : commands.entrySet()) {
-            Logger.info("%s - %s", entry.getKey(), entry.getValue().description());
+            Log.info("%s - %s", entry.getKey(), entry.getValue().description());
         }
     }
 

src/main/java/ua/nanit/limbo/server/commands/CmdMem.java

@@ -1,7 +1,7 @@
 package ua.nanit.limbo.server.commands;
 
 import ua.nanit.limbo.server.Command;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 public class CmdMem implements Command {
 
@@ -14,11 +14,11 @@ public class CmdMem implements Command {
         long free = runtime.freeMemory() / mb;
         long max = runtime.maxMemory() / mb;
 
-        Logger.info("Memory usage:");
-        Logger.info("Used: %d MB", used);
-        Logger.info("Total: %d MB", total);
-        Logger.info("Free: %d MB", free);
-        Logger.info("Max: %d MB", max);
+        Log.info("Memory usage:");
+        Log.info("Used: %d MB", used);
+        Log.info("Total: %d MB", total);
+        Log.info("Free: %d MB", free);
+        Log.info("Max: %d MB", max);
     }
 
     @Override

src/main/java/ua/nanit/limbo/server/commands/CmdVersion.java

@@ -0,0 +1,18 @@
+package ua.nanit.limbo.server.commands;
+
+import ua.nanit.limbo.server.Command;
+import ua.nanit.limbo.server.Log;
+import ua.nanit.limbo.BuildConfig;
+
+public class CmdVersion implements Command {
+
+    @Override
+    public void execute() {
+        Log.info("Version: %s", BuildConfig.LIMBO_VERSION);
+    }
+
+    @Override
+    public String description() {
+        return "Display limbo version";
+    }
+}

src/main/java/ua/nanit/limbo/server/data/BossBar.java

@@ -21,18 +21,20 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 import org.spongepowered.configurate.ConfigurationNode;
 import org.spongepowered.configurate.serialize.SerializationException;
 import org.spongepowered.configurate.serialize.TypeSerializer;
+import ua.nanit.limbo.protocol.NbtMessage;
 import ua.nanit.limbo.util.Colors;
+import ua.nanit.limbo.util.NbtMessageUtil;
 
 import java.lang.reflect.Type;
 
 public class BossBar {
 
-    private String text;
+    private NbtMessage text;
     private float health;
     private Color color;
     private Division division;
 
-    public String getText() {
+    public NbtMessage getText() {
         return text;
     }
 
@@ -48,7 +50,7 @@ public class BossBar {
         return division;
     }
 
-    public void setText(String text) {
+    public void setText(NbtMessage text) {
         this.text = text;
     }
 
@@ -110,7 +112,7 @@ public class BossBar {
         public BossBar deserialize(Type type, ConfigurationNode node) throws SerializationException {
             BossBar bossBar = new BossBar();
 
-            bossBar.setText(Colors.of(node.node("text").getString("")));
+            bossBar.setText(NbtMessageUtil.create(Colors.of(node.node("text").getString(""))));
             bossBar.setHealth(node.node("health").getFloat());
 
             if (bossBar.getHealth() < 0 || bossBar.getHealth() > 1)

src/main/java/ua/nanit/limbo/server/data/Title.java

@@ -20,23 +20,25 @@ package ua.nanit.limbo.server.data;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.spongepowered.configurate.ConfigurationNode;
 import org.spongepowered.configurate.serialize.TypeSerializer;
+import ua.nanit.limbo.protocol.NbtMessage;
 import ua.nanit.limbo.util.Colors;
+import ua.nanit.limbo.util.NbtMessageUtil;
 
 import java.lang.reflect.Type;
 
 public class Title {
 
-    private String title;
-    private String subtitle;
+    private NbtMessage title;
+    private NbtMessage subtitle;
     private int fadeIn;
     private int stay;
     private int fadeOut;
 
-    public String getTitle() {
+    public NbtMessage getTitle() {
         return title;
     }
 
-    public String getSubtitle() {
+    public NbtMessage getSubtitle() {
         return subtitle;
     }
 
@@ -52,11 +54,11 @@ public class Title {
         return fadeOut;
     }
 
-    public void setTitle(String title) {
+    public void setTitle(NbtMessage title) {
         this.title = title;
     }
 
-    public void setSubtitle(String subtitle) {
+    public void setSubtitle(NbtMessage subtitle) {
         this.subtitle = subtitle;
     }
 
@@ -77,8 +79,8 @@ public class Title {
         @Override
         public Title deserialize(Type type, ConfigurationNode node) {
             Title title = new Title();
-            title.setTitle(Colors.of(node.node("title").getString("")));
-            title.setSubtitle(Colors.of(node.node("subtitle").getString("")));
+            title.setTitle(NbtMessageUtil.create(Colors.of(node.node("title").getString(""))));
+            title.setSubtitle(NbtMessageUtil.create(Colors.of(node.node("subtitle").getString(""))));
             title.setFadeIn(node.node("fadeIn").getInt(10));
             title.setStay(node.node("stay").getInt(100));
             title.setFadeOut(node.node("fadeOut").getInt(10));

src/main/java/ua/nanit/limbo/util/NbtMessageUtil.java

@@ -0,0 +1,110 @@
+package ua.nanit.limbo.util;
+
+import com.google.gson.*;
+import net.kyori.adventure.nbt.*;
+import ua.nanit.limbo.protocol.NbtMessage;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+public class NbtMessageUtil {
+
+    public static NbtMessage create(String json) {
+        BinaryTag compoundBinaryTag = fromJson(JsonParser.parseString(json));
+
+        return new NbtMessage(json, compoundBinaryTag);
+    }
+
+    public static BinaryTag fromJson(JsonElement json) {
+        if (json instanceof JsonPrimitive) {
+            JsonPrimitive jsonPrimitive = (JsonPrimitive) json;
+            if (jsonPrimitive.isNumber()) {
+                Number number = json.getAsNumber();
+
+                if (number instanceof Byte) {
+                    return ByteBinaryTag.byteBinaryTag((Byte) number);
+                } else if (number instanceof Short) {
+                    return ShortBinaryTag.shortBinaryTag((Short) number);
+                } else if (number instanceof Integer) {
+                    return IntBinaryTag.intBinaryTag((Integer) number);
+                } else if (number instanceof Long) {
+                    return LongBinaryTag.longBinaryTag((Long) number);
+                } else if (number instanceof Float) {
+                    return FloatBinaryTag.floatBinaryTag((Float) number);
+                } else if (number instanceof Double) {
+                    return DoubleBinaryTag.doubleBinaryTag((Double) number);
+                }
+            } else if (jsonPrimitive.isString()) {
+                return StringBinaryTag.stringBinaryTag(jsonPrimitive.getAsString());
+            } else if (jsonPrimitive.isBoolean()) {
+                return ByteBinaryTag.byteBinaryTag(jsonPrimitive.getAsBoolean() ? (byte) 1 : (byte) 0);
+            } else {
+                throw new IllegalArgumentException("Unknown JSON primitive: " + jsonPrimitive);
+            }
+        } else if (json instanceof JsonObject) {
+            CompoundBinaryTag.Builder builder = CompoundBinaryTag.builder();
+            for (Map.Entry<String, JsonElement> property : ((JsonObject) json).entrySet()) {
+                builder.put(property.getKey(), fromJson(property.getValue()));
+            }
+
+            return builder.build();
+        } else if (json instanceof JsonArray) {
+            List<JsonElement> jsonArray = ((JsonArray) json).asList();
+
+            if (jsonArray.isEmpty()) {
+                return ListBinaryTag.listBinaryTag(EndBinaryTag.endBinaryTag().type(), Collections.emptyList());
+            }
+
+            BinaryTagType tagByteType = ByteBinaryTag.ZERO.type();
+            BinaryTagType tagIntType = IntBinaryTag.intBinaryTag(0).type();
+            BinaryTagType tagLongType = LongBinaryTag.longBinaryTag(0).type();
+
+            BinaryTag listTag;
+            BinaryTagType listType = fromJson(jsonArray.get(0)).type();
+            if (listType.equals(tagByteType)) {
+                byte[] bytes = new byte[jsonArray.size()];
+                for (int i = 0; i < bytes.length; i++) {
+                    bytes[i] = (Byte) ((JsonPrimitive) jsonArray.get(i)).getAsNumber();
+                }
+
+                listTag = ByteArrayBinaryTag.byteArrayBinaryTag(bytes);
+            } else if (listType.equals(tagIntType)) {
+                int[] ints = new int[jsonArray.size()];
+                for (int i = 0; i < ints.length; i++) {
+                    ints[i] = (Integer) ((JsonPrimitive) jsonArray.get(i)).getAsNumber();
+                }
+
+                listTag = IntArrayBinaryTag.intArrayBinaryTag(ints);
+            } else if (listType.equals(tagLongType)) {
+                long[] longs = new long[jsonArray.size()];
+                for (int i = 0; i < longs.length; i++) {
+                    longs[i] = (Long) ((JsonPrimitive) jsonArray.get(i)).getAsNumber();
+                }
+
+                listTag = LongArrayBinaryTag.longArrayBinaryTag(longs);
+            } else {
+                List<BinaryTag> tagItems = new ArrayList<>(jsonArray.size());
+
+                for (JsonElement jsonEl : jsonArray) {
+                    BinaryTag subTag = fromJson(jsonEl);
+                    if (subTag.type() != listType) {
+                        throw new IllegalArgumentException("Cannot convert mixed JsonArray to Tag");
+                    }
+
+                    tagItems.add(subTag);
+                }
+
+                listTag = ListBinaryTag.listBinaryTag(listType, tagItems);
+            }
+
+            return listTag;
+        } else if (json instanceof JsonNull) {
+            return EndBinaryTag.endBinaryTag();
+        }
+
+        throw new IllegalArgumentException("Unknown JSON element: " + json);
+    }
+
+}

src/main/java/ua/nanit/limbo/world/DimensionRegistry.java

@@ -21,7 +21,7 @@ import net.kyori.adventure.nbt.CompoundBinaryTag;
 import net.kyori.adventure.nbt.ListBinaryTag;
 import net.kyori.adventure.nbt.TagStringIO;
 import ua.nanit.limbo.server.LimboServer;
-import ua.nanit.limbo.server.Logger;
+import ua.nanit.limbo.server.Log;
 
 import java.io.*;
 import java.nio.charset.StandardCharsets;
@@ -33,6 +33,8 @@ public final class DimensionRegistry {
 
     private Dimension defaultDimension_1_16;
     private Dimension defaultDimension_1_18_2;
+    private Dimension dimension_1_20_5;
+    private Dimension dimension_1_21;
 
     private CompoundBinaryTag codec_1_16;
     private CompoundBinaryTag codec_1_18_2;
@@ -40,6 +42,7 @@ public final class DimensionRegistry {
     private CompoundBinaryTag codec_1_19_1;
     private CompoundBinaryTag codec_1_19_4;
     private CompoundBinaryTag codec_1_20;
+    private CompoundBinaryTag codec_1_21;
     private CompoundBinaryTag oldCodec;
 
     public DimensionRegistry(LimboServer server) {
@@ -70,6 +73,10 @@ public final class DimensionRegistry {
         return codec_1_20;
     }
 
+    public CompoundBinaryTag getCodec_1_21() {
+        return codec_1_21;
+    }
+
     public CompoundBinaryTag getOldCodec() {
         return oldCodec;
     }
@@ -82,18 +89,30 @@ public final class DimensionRegistry {
         return defaultDimension_1_18_2;
     }
 
+    public Dimension getDimension_1_20_5() {
+        return dimension_1_20_5;
+    }
+
+    public Dimension getDimension_1_21() {
+        return dimension_1_21;
+    }
+
     public void load(String def) throws IOException {
+        // On 1.16-1.16.1 different codec format
+        oldCodec = readCodecFile("/dimension/codec_old.snbt");
         codec_1_16 = readCodecFile("/dimension/codec_1_16.snbt");
         codec_1_18_2 = readCodecFile("/dimension/codec_1_18_2.snbt");
         codec_1_19 = readCodecFile("/dimension/codec_1_19.snbt");
         codec_1_19_1 = readCodecFile("/dimension/codec_1_19_1.snbt");
         codec_1_19_4 = readCodecFile("/dimension/codec_1_19_4.snbt");
         codec_1_20 = readCodecFile("/dimension/codec_1_20.snbt");
-        // On 1.16-1.16.1 different codec format
-        oldCodec = readCodecFile("/dimension/codec_old.snbt");
+        codec_1_21 = readCodecFile("/dimension/codec_1_21.snbt");
 
         defaultDimension_1_16 = getDefaultDimension(def, codec_1_16);
         defaultDimension_1_18_2 = getDefaultDimension(def, codec_1_18_2);
+
+        dimension_1_20_5 = getModernDimension(def, codec_1_20);
+        dimension_1_21 = getModernDimension(def, codec_1_21);
     }
 
     private Dimension getDefaultDimension(String def, CompoundBinaryTag tag) {
@@ -111,29 +130,37 @@ public final class DimensionRegistry {
             case "the_end":
                 return new Dimension(1, "minecraft:the_end", theEnd);
             default:
-                Logger.warning("Undefined dimension type: '%s'. Using THE_END as default", def);
+                Log.warning("Undefined dimension type: '%s'. Using THE_END as default", def);
                 return new Dimension(1, "minecraft:the_end", theEnd);
         }
     }
 
+    private Dimension getModernDimension(String def, CompoundBinaryTag tag) {
+        switch (def.toLowerCase()) {
+            case "overworld":
+                return new Dimension(0, "minecraft:overworld", tag);
+            case "the_nether":
+                return new Dimension(2, "minecraft:nether", tag);
+            case "the_end":
+                return new Dimension(3, "minecraft:the_end", tag);
+            default:
+                Log.warning("Undefined dimension type: '%s'. Using THE_END as default", def);
+                return new Dimension(3, "minecraft:the_end", tag);
+        }
+    }
+
     private CompoundBinaryTag readCodecFile(String resPath) throws IOException {
         InputStream in = server.getClass().getResourceAsStream(resPath);
 
-        if(in == null)
+        if (in == null)
             throw new FileNotFoundException("Cannot find dimension registry file");
 
         return TagStringIO.get().asCompound(streamToString(in));
     }
 
     private String streamToString(InputStream in) throws IOException {
-        InputStreamReader isReader = new InputStreamReader(in, StandardCharsets.UTF_8);
-        BufferedReader bufReader = new BufferedReader(isReader);
-        String content = bufReader.lines()
-                .collect(Collectors.joining("\n"));
-
-        isReader.close();
-        bufReader.close();
-
-        return content;
+        try (BufferedReader bufReader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8))) {
+            return bufReader.lines().collect(Collectors.joining("\n"));
+        }
     }
 }

src/main/resources/logback.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE configuration>
+
+<configuration>
+    <import class="ch.qos.logback.classic.encoder.PatternLayoutEncoder"/>
+    <import class="ch.qos.logback.core.ConsoleAppender"/>
+    <import class="ch.qos.logback.core.FileAppender"/>
+
+    <timestamp key="bySecond" datePattern="yyyy-MM-dd"/>
+
+    <appender name="STDOUT" class="ConsoleAppender">
+        <encoder class="PatternLayoutEncoder">
+            <pattern>%d{HH:mm:ss.SSS} %-5level %logger{36} -%kvp- %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <appender name="FILE" class="FileAppender">
+        <file>logs/log-${bySecond}.txt</file>
+        <immediateFlush>true</immediateFlush>
+
+        <encoder class="PatternLayoutEncoder">
+            <pattern>%d{HH:mm:ss.SSS} %-5level %logger{36} -%kvp- %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="FILE"/>
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>

src/main/resources/settings.yml

@@ -7,7 +7,7 @@ bind:
   ip: 'localhost'
   port: 65535
 
-# Max amount of players can join to server
+# Max number of players can join to server
 # Set -1 to make it infinite
 maxPlayers: 100
 
@@ -16,7 +16,7 @@ ping:
   description: '{"text": "&9NanoLimbo"}'
   version: 'NanoLimbo'
   # Return static protocol version number in ping result
-  # By default, its -1 to return the client version, if it supported
+  # By default, its -1 to return the client version if it supported
   # https://wiki.vg/Protocol_version_numbers
   protocol: -1
 
@@ -24,7 +24,7 @@ ping:
 dimension: THE_END
 
 # Whether to display the player in the player list
-# For 1.16.5 clients, player list will be sent even if disabled, to avoid crash
+# For 1.16.5 clients, the player list will be sent even if disabled, to avoid crash
 playerList:
   enable: false
   username: 'NanoLimbo'
@@ -50,12 +50,12 @@ brandName:
   enable: true
   content: 'NanoLimbo'
 
-# Message sends when player join to server
+# Message sends when player joins to the server
 joinMessage:
   enable: true
   text: '{"text": "&eWelcome to the Limbo!"}'
 
-# BossBar displays when player join to server
+# BossBar displays when player joins to the server
 # For 1.9+ clients
 bossBar:
   enable: true
@@ -87,7 +87,7 @@ title:
 #  - LEGACY
 #  - MODERN
 #  - BUNGEE_GUARD
-# Don't use secret if you not use MODERN type
+# Don't use secret if you do not use MODERN type
 infoForwarding:
   type: NONE
   secret: '<YOUR_SECRET_HERE>'
@@ -105,11 +105,29 @@ readTimeout: 30000
 # 3 - Display errors, warnings, info, debug
 debugLevel: 2
 
-# Warning! Do not touch params of this block, if you not completely sure what is this!
+# Warning! Do not touch params of this block if you are not completely sure what is this!
 netty:
-  # Use Linux native transport type, if it possible
+  # Use a Linux native transport type, if it possible
   useEpoll: true
   # EventLoopGroup threads count
   threads:
     bossGroup: 1
     workerGroup: 4
+
+# Options to check incoming traffic and kick potentially malicious connections.
+# Take into account that player can send many small packets, for example, just moving mouse.
+traffic:
+  # If true, then additional handler will be added to the channel pipeline
+  enable: true
+  # Max packet size in bytes
+  # Unlimited if -1
+  maxPacketSize: 8192
+  # The interval to measure packets over
+  # Lowering this value will limit peak packets from players which would target people with bad connections
+  # Raising this value will allow higher peak packet rates, which will help with people who have poor connections
+  # Ignored if -1.0
+  interval: 7.0
+  # The maximum packets per second for players
+  # It is measured over the configured interval
+  # Ignored if -1.0
+  maxPacketRate: 500.0