Chunk packet. Counting players and kicking if too many

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

@@ -3,6 +3,7 @@ package ru.nanit.limbo;
 import ru.nanit.limbo.server.LimboServer;
 import ru.nanit.limbo.util.Logger;
 import ru.nanit.limbo.world.DefaultDimension;
+import ru.nanit.limbo.world.DefaultWorld;
 
 import java.io.InputStream;
 import java.nio.file.Paths;
@@ -14,6 +15,7 @@ public final class NanoLimbo {
     public void start() throws Exception {
         LimboConfig.load(Paths.get("./settings.properties"));
         DefaultDimension.init();
+        DefaultWorld.init();
 
         server = new LimboServer();
         server.start();

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

@@ -4,11 +4,10 @@ import io.netty.channel.Channel;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
+import net.kyori.adventure.nbt.CompoundBinaryTag;
 import ru.nanit.limbo.LimboConfig;
 import ru.nanit.limbo.protocol.packets.login.*;
-import ru.nanit.limbo.protocol.packets.play.PacketJoinGame;
-import ru.nanit.limbo.protocol.packets.play.PacketPlayerPositionAndLook;
-import ru.nanit.limbo.protocol.packets.play.PacketUpdateViewPos;
+import ru.nanit.limbo.protocol.packets.play.*;
 import ru.nanit.limbo.protocol.registry.Version;
 import ru.nanit.limbo.protocol.pipeline.PacketDecoder;
 import ru.nanit.limbo.protocol.pipeline.PacketEncoder;
@@ -21,6 +20,7 @@ import ru.nanit.limbo.server.LimboServer;
 import ru.nanit.limbo.util.Logger;
 import ru.nanit.limbo.util.UuidUtil;
 import ru.nanit.limbo.world.DefaultDimension;
+import ru.nanit.limbo.world.DefaultWorld;
 
 import java.util.concurrent.ThreadLocalRandom;
 
@@ -33,13 +33,14 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
     private String username;
 
     public ClientConnection(Channel channel, LimboServer server){
-        this.channel = channel;
         this.server = server;
+        this.channel = channel;
     }
 
     @Override
     public void channelInactive(ChannelHandlerContext ctx) throws Exception {
         if (state.equals(State.PLAY)){
+            server.decrementPlayers();
             Logger.info("Player %s disconnected", this.username);
         }
         super.channelInactive(ctx);
@@ -47,7 +48,9 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
-        Logger.error("Unhandled exception: %s", cause.getMessage());
+        if (channel.isActive()){
+            Logger.error("Unhandled exception: %s", cause.getMessage());
+        }
     }
 
     @Override
@@ -71,6 +74,11 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
         }
 
         if (packet instanceof PacketLoginStart){
+            if (server.getPlayersCount() >= LimboConfig.getMaxPlayers()){
+                disconnect("Too many players connected");
+                return;
+            }
+
             this.username = ((PacketLoginStart) packet).getUsername();
 
             PacketLoginSuccess loginSuccess = new PacketLoginSuccess();
@@ -80,9 +88,16 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
 
             sendPacket(loginSuccess);
             updateState(State.PLAY);
+
+            server.incrementPlayers();
             Logger.info("Player %s connected", this.username);
+
             startJoinProcess();
         }
+
+        if (packet instanceof PacketKeepAlive){
+            System.out.println("Get KeepAlive " + ((PacketKeepAlive)packet).getId());
+        }
     }
 
     private void startJoinProcess(){
@@ -118,9 +133,40 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
         updateViewPos.setChunkX(0);
         updateViewPos.setChunkY(0);
 
+        PacketChunkData chunkData = new PacketChunkData();
+
+        chunkData.setChunkX(0);
+        chunkData.setChunkZ(0);
+        chunkData.setFullChunk(false);
+        chunkData.setPrimaryBitMask(1);
+        chunkData.setHeightMaps(DefaultWorld.getHeightMaps());
+        chunkData.setData(new byte[0]);
+        chunkData.setBlockEntities(new CompoundBinaryTag[]{CompoundBinaryTag.empty()});
+
         sendPacket(joinGame);
         sendPacket(positionAndLook);
         sendPacket(updateViewPos);
+        sendPacket(chunkData);
+        sendPacket(updateViewPos);
+        sendPacket(positionAndLook);
+
+        sendKeepAlive();
+    }
+
+    public void disconnect(String reason){
+        if (isConnected() && state == State.LOGIN){
+            PacketDisconnect disconnect = new PacketDisconnect();
+            disconnect.setReason(reason);
+            sendPacketAndClose(disconnect);
+        }
+    }
+
+    public void sendKeepAlive(){
+        if (state.equals(State.PLAY)){
+            PacketKeepAlive keepAlive = new PacketKeepAlive();
+            keepAlive.setId(ThreadLocalRandom.current().nextLong());
+            sendPacket(keepAlive);
+        }
     }
 
     public void sendPacket(Object packet){
@@ -133,18 +179,6 @@ public class ClientConnection extends ChannelInboundHandlerAdapter {
             channel.writeAndFlush(packet).addListener(ChannelFutureListener.CLOSE);
     }
 
-    public void disconnect(){
-        if (channel.isActive()){
-            channel.close();
-        }
-    }
-
-    public void disconnect(String reason){
-        PacketDisconnect packet = new PacketDisconnect();
-        packet.setReason(reason);
-        sendPacketAndClose(packet);
-    }
-
     public boolean isConnected(){
         return channel.isActive();
     }

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

@@ -120,6 +120,27 @@ public class ByteMessage extends ByteBuf {
         }
     }
 
+    public void writeVarIntArray(int[] array) {
+        writeVarInt(array.length);
+        for (int i : array) {
+            writeVarInt(i);
+        }
+    }
+
+    public void writeCompoundTagArray(CompoundBinaryTag[] compoundTags) {
+        try {
+            ByteBufOutputStream stream = new ByteBufOutputStream(buf);
+
+            writeVarInt(compoundTags.length);
+
+            for (CompoundBinaryTag tag : compoundTags){
+                BinaryTagIO.writeDataOutput(tag, stream);
+            }
+        } catch (IOException e) {
+            throw new EncoderException("Cannot write NBT CompoundTag");
+        }
+    }
+
     public CompoundBinaryTag readCompoundTag() {
         try {
             return BinaryTagIO.readDataInput(new ByteBufInputStream(buf));

src/main/java/ru/nanit/limbo/protocol/packets/play/PacketChunkData.java

@@ -0,0 +1,69 @@
+package ru.nanit.limbo.protocol.packets.play;
+
+import net.kyori.adventure.nbt.CompoundBinaryTag;
+import ru.nanit.limbo.protocol.ByteMessage;
+import ru.nanit.limbo.protocol.PacketOut;
+import ru.nanit.limbo.protocol.registry.Version;
+
+public class PacketChunkData implements PacketOut {
+
+    private int chunkX;
+    private int chunkZ;
+    private boolean fullChunk;
+    private int primaryBitMask;
+    private CompoundBinaryTag heightMaps;
+    private int[] biomes;
+    private byte[] data;
+    private CompoundBinaryTag[] blockEntities;
+
+    public void setChunkX(int chunkX) {
+        this.chunkX = chunkX;
+    }
+
+    public void setChunkZ(int chunkZ) {
+        this.chunkZ = chunkZ;
+    }
+
+    public void setFullChunk(boolean fullChunk) {
+        this.fullChunk = fullChunk;
+    }
+
+    public void setPrimaryBitMask(int primaryBitMask) {
+        this.primaryBitMask = primaryBitMask;
+    }
+
+    public void setHeightMaps(CompoundBinaryTag heightMaps) {
+        this.heightMaps = heightMaps;
+    }
+
+    public void setBiomes(int[] biomes) {
+        this.biomes = biomes;
+    }
+
+    public void setData(byte[] data) {
+        this.data = data;
+    }
+
+    public void setBlockEntities(CompoundBinaryTag[] blockEntities) {
+        this.blockEntities = blockEntities;
+    }
+
+    @Override
+    public void encode(ByteMessage msg, Version version) {
+        msg.writeInt(chunkX);
+        msg.writeInt(chunkZ);
+        msg.writeBoolean(fullChunk);
+        msg.writeVarInt(primaryBitMask);
+        msg.writeCompoundTag(heightMaps);
+
+        if (fullChunk){
+            msg.writeVarIntArray(biomes);
+        }
+
+
+
+        msg.writeBytesArray(data);
+        msg.writeCompoundTagArray(blockEntities);
+    }
+
+}

src/main/java/ru/nanit/limbo/protocol/packets/play/PacketKeepAlive.java

@@ -0,0 +1,29 @@
+package ru.nanit.limbo.protocol.packets.play;
+
+import ru.nanit.limbo.protocol.ByteMessage;
+import ru.nanit.limbo.protocol.Packet;
+import ru.nanit.limbo.protocol.registry.Version;
+
+public class PacketKeepAlive implements Packet {
+
+    private long id;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    @Override
+    public void encode(ByteMessage msg, Version version) {
+        msg.writeLong(id);
+    }
+
+    @Override
+    public void decode(ByteMessage msg, Version version) {
+        this.id = msg.readLong();
+    }
+
+}

src/main/java/ru/nanit/limbo/protocol/packets/play/PacketPlayerPositionAndLook.java

@@ -11,7 +11,7 @@ public class PacketPlayerPositionAndLook implements PacketOut {
     private double z;
     private float yaw;
     private float pitch;
-    private byte flags = 0x01;
+    private byte flags = 0x08;
     private int teleportId;
 
     public void setX(double x) {

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

@@ -3,9 +3,7 @@ package ru.nanit.limbo.protocol.registry;
 import ru.nanit.limbo.protocol.Packet;
 import ru.nanit.limbo.protocol.packets.*;
 import ru.nanit.limbo.protocol.packets.login.*;
-import ru.nanit.limbo.protocol.packets.play.PacketJoinGame;
-import ru.nanit.limbo.protocol.packets.play.PacketPlayerPositionAndLook;
-import ru.nanit.limbo.protocol.packets.play.PacketUpdateViewPos;
+import ru.nanit.limbo.protocol.packets.play.*;
 import ru.nanit.limbo.protocol.packets.status.PacketStatusPing;
 import ru.nanit.limbo.protocol.packets.status.PacketStatusRequest;
 import ru.nanit.limbo.protocol.packets.status.PacketStatusResponse;
@@ -38,9 +36,12 @@ public enum State {
     },
     PLAY(3){
         {
+            clientBound.register(Version.V1_16_4, 0x20, PacketChunkData::new);
             clientBound.register(Version.V1_16_4, 0x24, PacketJoinGame::new);
             clientBound.register(Version.V1_16_4, 0x34, PacketPlayerPositionAndLook::new);
             clientBound.register(Version.V1_16_4, 0x40, PacketUpdateViewPos::new);
+            clientBound.register(Version.V1_16_4, 0x1F, PacketKeepAlive::new);
+            serverBound.register(Version.V1_16_4, 0x1F, PacketKeepAlive::new);
         }
     };
 

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

@@ -7,11 +7,29 @@ import ru.nanit.limbo.LimboConfig;
 import ru.nanit.limbo.connection.ClientChannelInitializer;
 import ru.nanit.limbo.util.Logger;
 
+import java.util.concurrent.atomic.AtomicInteger;
+
 public final class LimboServer {
 
+    private AtomicInteger playersCount;
+
+    public int getPlayersCount(){
+        return playersCount.get();
+    }
+
+    public void incrementPlayers(){
+        playersCount.incrementAndGet();
+    }
+
+    public void decrementPlayers(){
+        playersCount.decrementAndGet();
+    }
+
     public void start() throws Exception {
         Logger.info("Starting server...");
 
+        playersCount = new AtomicInteger();
+
         ServerBootstrap bootstrap = new ServerBootstrap()
                 .group(new NioEventLoopGroup(), new NioEventLoopGroup())
                 .channel(NioServerSocketChannel.class)

src/main/java/ru/nanit/limbo/world/DefaultWorld.java

@@ -0,0 +1,32 @@
+package ru.nanit.limbo.world;
+
+import net.kyori.adventure.nbt.CompoundBinaryTag;
+
+public final class DefaultWorld {
+
+    private static CompoundBinaryTag heightMaps;
+
+    private DefaultWorld(){}
+
+    public static void init(){
+        heightMaps = CompoundBinaryTag.builder()
+                .putLongArray("MOTION_BLOCKING", new long[]{
+                        1371773531765642314L, 1389823183635651148L, 1371738278539598925L,
+                        1389823183635388492L, 1353688558756731469L, 1389823114781694027L, 1317765589597723213L,
+                        1371773531899860042L, 1389823183635651149L, 1371773462911685197L, 1389823183635650636L,
+                        1353688626805119565L, 1371773531900123211L, 1335639250618849869L, 1371738278674077258L,
+                        1389823114781694028L, 1353723811310638154L, 1371738278674077259L, 1335674228429068364L,
+                        1335674228429067338L, 1335674228698027594L, 1317624576693539402L, 1335709481520370249L,
+                        1299610178184057417L, 1335638906349064264L, 1299574993811968586L, 1299574924958011464L,
+                        1299610178184056904L, 1299574924958011464L, 1299610109330100296L, 1299574924958011464L,
+                        1299574924823793736L, 1299574924958011465L, 1281525273222484040L, 1299574924958011464L,
+                        1281525273222484040L, 9548107335L
+                })
+                .build();
+    }
+
+    public static CompoundBinaryTag getHeightMaps(){
+        return heightMaps;
+    }
+
+}

src/main/resources/settings.properties

@@ -5,12 +5,14 @@
 host=localhost
 port=65535
 max-players=100
+ping-version=NanoLimbo
+ping-description={"text": "NanoLimbo"}
 
-# Proxy forwarding support. Available types: NONE, LEGACY, MODERN
+# Player info forwarding support. Available types: NONE, LEGACY, MODERN
 ip-forwarding=LEGACY
 
-# Read timeout for connections in milliseconds
-read-timeout=30000
+# If you use MODERN type of forwarding, enter your secret code here
+ip-forwarding-secret=<YOUR_SECRET_HERE>
 
-ping-version=NanoLimbo
-ping-description={"text": "NanoLimbo"}
+# Read timeout for connections in milliseconds
+read-timeout=30000