перенос кода в подмодуль

server/src/main/java/mc/protocol/NetworkAttributes.java

@@ -0,0 +1,10 @@
+package mc.protocol;
+
+import io.netty.util.AttributeKey;
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class NetworkAttributes {
+
+	public static final AttributeKey<State> STATE = AttributeKey.newInstance("STATE");
+}

server/src/main/java/mc/protocol/State.java

@@ -0,0 +1,77 @@
+package mc.protocol;
+
+import com.google.common.collect.BiMap;
+import com.google.common.collect.ImmutableBiMap;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import mc.protocol.packets.Packet;
+import mc.protocol.packets.PacketDirection;
+import mc.protocol.packets.client.HandshakePacket;
+import mc.protocol.packets.client.LoginStartPacket;
+import mc.protocol.packets.client.StatusServerRequest;
+import mc.protocol.packets.server.DisconnectPacket;
+import mc.protocol.packets.server.StatusServerResponse;
+
+import javax.annotation.Nullable;
+
+@RequiredArgsConstructor
+public enum State {
+
+	HANDSHAKING(-1,
+			// server bound
+			ImmutableBiMap.of(0x00, HandshakePacket.class)
+	),
+	STATUS(1,
+			// server bound
+			ImmutableBiMap.of(0x00, StatusServerRequest.class),
+			// client bound
+			ImmutableBiMap.of(0x00, StatusServerResponse.class)
+	),
+	LOGIN(2,
+			// server bound
+			ImmutableBiMap.of(0x00, LoginStartPacket.class),
+			// client bound
+			ImmutableBiMap.of(0x00, DisconnectPacket.class)
+	);
+
+	@Nullable
+	public static State getById(int id) {
+		for (State state : State.values()) {
+			if (state.id == id) {
+				return state;
+			}
+		}
+
+		return null;
+	}
+
+	@Getter
+	private final int id;
+
+	private final BiMap<Integer, Class<? extends Packet>> serverBoundPackets;
+	private final BiMap<Integer, Class<? extends Packet>> clientBoundPackets;
+
+	State(int id, BiMap<Integer, Class<? extends Packet>> serverBoundPackets) {
+		this.id = id;
+		this.serverBoundPackets = serverBoundPackets;
+		this.clientBoundPackets = ImmutableBiMap.of();
+	}
+
+	@Nullable
+	public Class<? extends Packet> getPacketById(PacketDirection direction, int id) {
+		if (PacketDirection.CLIENT_BOUND == direction) {
+			return clientBoundPackets == null ? null : clientBoundPackets.get(id);
+		} else {
+			return serverBoundPackets == null ? null : serverBoundPackets.get(id);
+		}
+	}
+
+	@Nullable
+	public Integer getIdByPacket(PacketDirection direction, Class<? extends Packet> clazz) {
+		if (PacketDirection.CLIENT_BOUND == direction) {
+			return clientBoundPackets == null ? null : clientBoundPackets.inverse().get(clazz);
+		} else {
+			return serverBoundPackets == null ? null : serverBoundPackets.inverse().get(clazz);
+		}
+	}
+}

server/src/main/java/mc/protocol/io/DecoderException.java

@@ -0,0 +1,8 @@
+package mc.protocol.io;
+
+public class DecoderException extends RuntimeException {
+
+    public DecoderException(String message) {
+        super(message);
+    }
+}

server/src/main/java/mc/protocol/io/NetByteBuf.java

@@ -0,0 +1,183 @@
+package mc.protocol.io;
+
+import io.netty.buffer.ByteBuf;
+import lombok.EqualsAndHashCode;
+import lombok.RequiredArgsConstructor;
+import lombok.ToString;
+import lombok.experimental.Delegate;
+import lombok.extern.slf4j.Slf4j;
+
+import java.nio.charset.StandardCharsets;
+import java.util.UUID;
+
+/**
+ * Компонент чтения и записи данных протокола.
+ *
+ * <p>Data types</p>
+ * <pre>
+ * | TYPE           | SIZE (bytes)          | ENCODING                                            | NOTES                                                                    |
+ * |----------------|-----------------------|-----------------------------------------------------|--------------------------------------------------------------------------|
+ * | Boolean        | 1                     | True или False                                      | True = 0x01; False = 0x00                                                |
+ * | Byte           | 1                     | Число от -128 до 127                                | 8-bit число со знаком                                                    |
+ * | Unsigned Byte  | 1                     | Число от 0 до 255                                   | 8-bit без знаковое число                                                 |
+ * | Short          | 2                     | Число от -32768 до 32767                            | 16-bit число со знаком                                                   |
+ * | Unsigned Short | 2                     | Число от -32768 до 32767                            | 16-bit без знаковое число                                                |
+ * | Int            | 4                     | Число от -2147483648 и 2147483647                   | 32-bit число со знаком                                                   |
+ * | Long           | 8                     | Число от -9223372036854775808 и 9223372036854775807 | 64-bit число со знаком                                                   |
+ * | Float          | 4                     | 32-bit число одинарной точности (IEEE 754-2008)     | [1]                                                                      |
+ * | Double         | 8                     | 64-bit число одинарной точности (IEEE 754-2008)     | [2]                                                                      |
+ * | String (n)     | >= 1 ; <= (n * 4) + 3 | Последовательность Unicode scalar values            | В начале пишется длина строки в VarInt, после чего записываются символы. |
+ * |                |                       |                                                     | Каждый символ может состоять максимум из 4 байт. [3]                     |
+ * |                |                       |                                                     | Максимальная длина строки - 32767 (3 - это как раз размер VarInt для     |
+ * |                |                       |                                                     | этого числа).                                                            |
+ * | VarInt         | >= 1 ; <= 5           | Число от -2147483648 и 2147483647                   | 32-bit число с плавающей размерностью от 1 до 5 байт                     |
+ * | VarLong        | >= 1 ; <= 10          | Число от -9223372036854775808 и 9223372036854775807 | 64-bit число с плавающей размерностью от 1 до 10 байт                    |
+ *
+ * [1] - <a href="https://en.wikipedia.org/wiki/Single-precision_floating-point_format">Single-precision floating-point format</a>
+ * [2] - <a href="https://en.wikipedia.org/wiki/Double-precision_floating-point_format">Double-precision floating-point format</a>
+ * [3] - <a href="http://unicode.org/glossary/#unicode_scalar_value">Unicode Scalar Value</a>
+ * </pre>
+ *
+ * @see <a href="https://wiki.vg/index.php?title=Protocol&oldid=7368#Data_types">Data types</a>
+ */
+@Slf4j
+@RequiredArgsConstructor
+@EqualsAndHashCode(callSuper = false)
+@ToString
+public class NetByteBuf extends ByteBuf {
+
+	@Delegate
+	private final ByteBuf byteBuf;
+
+	//region String
+	public String readString() {
+		return readString(Short.MAX_VALUE);
+	}
+
+	@SuppressWarnings("java:S131")
+	public String readString(int maxLength) {
+		int length = readVarInt();
+
+		if (length == 0) {
+			return "";
+		} else if (length > maxLength) {
+			throw new DecoderException("String length exceeds maximum length: " + length + " > " + maxLength);
+		} else if (length < 0) {
+			throw new DecoderException("String length less zero!");
+		}
+
+		byte[] bytes = new byte[length * 4];
+		int readbleBytes = 0;
+		for (int i = 0; i < length && readableBytes() > 0; i++) {
+			byte b = readByte();
+			bytes[readbleBytes++] = b;
+
+			switch ((b & 0xFF) >> 4) {
+				case 0b1100:
+				case 0b1101:
+					bytes[readbleBytes++] = readByte();
+					break;
+				case 0b1110:
+					bytes[readbleBytes++] = readByte();
+					bytes[readbleBytes++] = readByte();
+					break;
+				case 0b1111:
+					bytes[readbleBytes++] = readByte();
+					bytes[readbleBytes++] = readByte();
+					bytes[readbleBytes++] = readByte();
+					break;
+			}
+		}
+
+		return new String(bytes, 0, readbleBytes, StandardCharsets.UTF_8);
+	}
+
+	public void writeString(String string) {
+		byte[] buf;
+		int length = (int) string.codePoints().count();
+
+		if (length > Short.MAX_VALUE) {
+			log.warn("String is too long: {} > {}", length, Short.MAX_VALUE);
+			buf = string.substring(0, Short.MAX_VALUE).getBytes(StandardCharsets.UTF_8);
+			writeVarInt(Short.MAX_VALUE);
+		} else {
+			buf = string.getBytes(StandardCharsets.UTF_8);
+			writeVarInt(length);
+		}
+
+		writeBytes(buf);
+	}
+	//endregion
+
+	//region VarInt
+	public int readVarInt() {
+		int numRead = 0;
+		int result = 0;
+		byte read;
+		do {
+			if ((numRead + 1) > 5) {
+				log.warn("VarInt is too big");
+				break;
+			}
+			read = readByte();
+			int value = (read & 0b01111111);
+			result |= (value << (7 * numRead));
+
+			numRead++;
+		} while ((read & 0b10000000) != 0);
+
+		return result;
+	}
+
+	public void writeVarInt(int value) {
+		while ((value & -128) != 0) {
+			writeByte(value & 127 | 128);
+			value >>>= 7;
+		}
+
+		writeByte(value);
+	}
+	//endregion
+
+	//region VarLong
+	public long readVarLong() {
+		int numRead = 0;
+		long result = 0L;
+		byte read;
+		do {
+			if (numRead > 10) {
+				log.warn("VarLong is too big");
+				break;
+			}
+
+			read = readByte();
+			long value = (read & 0b01111111);
+			result |= (value << (7 * numRead));
+
+			numRead++;
+		} while ((read & 0b10000000) != 0);
+
+		return result;
+	}
+
+	public void writeVarLong(long value) {
+		while ((value & -128L) != 0L) {
+			writeByte((int) (value & 127L) | 128);
+			value >>>= 7;
+		}
+
+		writeByte((int) value);
+	}
+	//endregion
+
+	//region UUID
+	public UUID readUUID() {
+		return new UUID(readLong(), readLong());
+	}
+
+	public void writeUUID(UUID uuid) {
+		writeLong(uuid.getMostSignificantBits());
+		writeLong(uuid.getLeastSignificantBits());
+	}
+	//endregion
+}

server/src/main/java/mc/protocol/io/codec/ProtocolDecoder.java

@@ -0,0 +1,59 @@
+package mc.protocol.io.codec;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import mc.protocol.NetworkAttributes;
+import mc.protocol.State;
+import mc.protocol.io.NetByteBuf;
+import mc.protocol.packets.Packet;
+import mc.protocol.packets.PacketDirection;
+import mc.protocol.packets.UnknownPacket;
+
+import java.util.List;
+import java.util.Objects;
+
+@Slf4j
+@RequiredArgsConstructor
+public class ProtocolDecoder extends ByteToMessageDecoder {
+
+	private final boolean readUnknownPackets;
+
+	@Override
+	public void channelActive(ChannelHandlerContext ctx) throws Exception {
+		ctx.channel().attr(NetworkAttributes.STATE).set(State.HANDSHAKING);
+		super.channelActive(ctx);
+	}
+
+	@Override
+	public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+		ctx.channel().attr(NetworkAttributes.STATE).set(null);
+		super.channelInactive(ctx);
+	}
+
+	@Override
+	protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
+		State state = Objects.requireNonNull(ctx.channel().attr(NetworkAttributes.STATE).get());
+		NetByteBuf netByteBuf = new NetByteBuf(in);
+
+		int packetId = netByteBuf.readVarInt();
+		Class<? extends Packet> packetClass = state.getPacketById(PacketDirection.SERVER_BOUND, packetId);
+		if (packetClass == null) {
+			log.warn("Unkown packet: State {} ; Id {}", state, packetId);
+
+			if (readUnknownPackets) {
+				UnknownPacket unknownPacket = new UnknownPacket(state, packetId, netByteBuf.readableBytes());
+				unknownPacket.readSelf(netByteBuf);
+				out.add(unknownPacket);
+			} else {
+				netByteBuf.skipBytes(netByteBuf.readableBytes());
+			}
+		} else {
+			Packet packet = packetClass.getDeclaredConstructor().newInstance();
+			packet.readSelf(netByteBuf);
+			out.add(packet);
+		}
+	}
+}

server/src/main/java/mc/protocol/io/codec/ProtocolEncoder.java

@@ -0,0 +1,30 @@
+package mc.protocol.io.codec;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+import mc.protocol.NetworkAttributes;
+import mc.protocol.State;
+import mc.protocol.io.NetByteBuf;
+import mc.protocol.packets.Packet;
+import mc.protocol.packets.PacketDirection;
+
+import java.util.Objects;
+
+public class ProtocolEncoder extends MessageToByteEncoder<Packet> {
+
+	@Override
+	protected void encode(ChannelHandlerContext ctx, Packet packet, ByteBuf out) {
+		State state = ctx.channel().attr(NetworkAttributes.STATE).get();
+		int packetId = Objects.requireNonNull(state.getIdByPacket(PacketDirection.CLIENT_BOUND, packet.getClass()));
+
+		NetByteBuf buffer = new NetByteBuf(Unpooled.buffer());
+		buffer.writeVarInt(packetId);
+		packet.writeSelf(buffer);
+
+		NetByteBuf netByteBuf = new NetByteBuf(out);
+		netByteBuf.writeVarInt(buffer.readableBytes());
+		netByteBuf.writeBytes(buffer);
+	}
+}

server/src/main/java/mc/protocol/io/codec/ProtocolSplitter.java

@@ -0,0 +1,40 @@
+package mc.protocol.io.codec;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import mc.protocol.io.NetByteBuf;
+
+import java.util.List;
+
+public class ProtocolSplitter extends ByteToMessageDecoder {
+
+	@Override
+	protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
+		NetByteBuf netByteBuf = new NetByteBuf(in);
+		netByteBuf.markReaderIndex();
+
+		do {
+			byte[] sizePacketRaw = new byte[3];
+			for (int i = 0; i < 3; ++i) {
+				sizePacketRaw[i] = netByteBuf.readByte();
+
+				if (sizePacketRaw[i] >= 0) {
+					break;
+				}
+			}
+
+			int sizePacket = new NetByteBuf(Unpooled.wrappedBuffer(sizePacketRaw)).readVarInt();
+
+			if (netByteBuf.readableBytes() >= sizePacket) {
+				byte[] bytes = new byte[sizePacket];
+				netByteBuf.readBytes(bytes);
+				out.add(Unpooled.wrappedBuffer(bytes));
+			} else {
+				netByteBuf.resetReaderIndex();
+				break;
+			}
+		} while (netByteBuf.readableBytes() > 0);
+	}
+}

server/src/main/java/mc/protocol/packets/EmptyPacket.java

@@ -0,0 +1,16 @@
+package mc.protocol.packets;
+
+import mc.protocol.io.NetByteBuf;
+
+public abstract class EmptyPacket implements Packet {
+
+	@Override
+	public void readSelf(NetByteBuf netByteBuf) {
+		// empty
+	}
+
+	@Override
+	public void writeSelf(NetByteBuf netByteBuf) {
+		// empty
+	}
+}

server/src/main/java/mc/protocol/packets/Packet.java

@@ -0,0 +1,24 @@
+package mc.protocol.packets;
+
+import mc.protocol.io.NetByteBuf;
+
+/**
+ * Пакет.
+ *
+ * <p>Структура пакета</p>
+ * <pre>
+ * | FIELD       | TYPE   | NOTES                                     |
+ * |-------------|--------|-------------------------------------------|
+ * | SIZE        | VarInt | = sizeOf(PACKET ID) + sizeOf(PACKET DATA) |
+ * | PACKET ID   | VarInt |                                           |
+ * | PACKET DATA | bytes  |                                           |
+ * </pre>
+ *
+ * @see <a href="https://wiki.vg/index.php?title=Protocol&oldid=7368#Without_compression">Packet without compression</a>
+ */
+public interface Packet {
+
+	void readSelf(NetByteBuf netByteBuf);
+
+	void writeSelf(NetByteBuf netByteBuf);
+}

server/src/main/java/mc/protocol/packets/PacketDirection.java

@@ -0,0 +1,6 @@
+package mc.protocol.packets;
+
+public enum PacketDirection {
+
+    SERVER_BOUND, CLIENT_BOUND
+}

server/src/main/java/mc/protocol/packets/UnknownPacket.java

@@ -0,0 +1,27 @@
+package mc.protocol.packets;
+
+import lombok.Data;
+import lombok.ToString;
+import mc.protocol.State;
+import mc.protocol.io.NetByteBuf;
+
+@Data
+@ToString(exclude = "rawData")
+public class UnknownPacket implements Packet {
+
+    private final State state;
+    private final int id;
+    private final int dataSize;
+    private byte[] rawData;
+
+    @Override
+    public void readSelf(NetByteBuf netByteBuf) {
+        rawData = new byte[dataSize];
+        netByteBuf.readBytes(rawData);
+    }
+
+    @Override
+    public void writeSelf(NetByteBuf netByteBuf) {
+        netByteBuf.writeBytes(rawData);
+    }
+}

server/src/main/java/mc/protocol/packets/client/HandshakePacket.java

@@ -0,0 +1,57 @@
+package mc.protocol.packets.client;
+
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+import mc.protocol.State;
+import mc.protocol.io.NetByteBuf;
+import mc.protocol.packets.Packet;
+
+/**
+ * Handshake packet.
+ *
+ * <p>Данный пакет заставляет сервер переключить текущий {@link State}</p>
+ *
+ * <p>Структура пакета</p>
+ * <pre>
+ * | FIELD            | TYPE           | NOTES                                        |
+ * |------------------|----------------|----------------------------------------------|
+ * | Protocol version | VarInt         | Версия протокола [1]                         |
+ * | Server address   | Stirng         | Hostname или IP                              |
+ * | Server port      | Unsigned Short | Порт сервера                                 |
+ * | Next stage       | VarInt         | ID State на который необходимо переключиться |
+ *
+ * [1] - <a href="https://wiki.vg/Protocol_version_numbers" target="_top">Protocol version numbers</a>
+ * </pre>
+ *
+ * @see <a href="https://wiki.vg/index.php?title=Protocol&oldid=7368#Handshake" target="_top">Handshake</a>
+ * @see State
+ */
+@NoArgsConstructor
+@Getter
+@EqualsAndHashCode
+@ToString
+public class HandshakePacket implements Packet {
+
+	private int protocolVersion;
+	private String host;
+	private int port;
+	private State nextState;
+
+	@Override
+	public void readSelf(NetByteBuf netByteBuf) {
+		protocolVersion = netByteBuf.readVarInt();
+		host = netByteBuf.readString(255);
+		port = netByteBuf.readUnsignedShort();
+		nextState = State.getById(netByteBuf.readVarInt());
+	}
+
+	@Override
+	public void writeSelf(NetByteBuf netByteBuf) {
+		netByteBuf.writeVarInt(protocolVersion);
+		netByteBuf.writeString(host);
+		netByteBuf.writeShort(port);
+		netByteBuf.writeVarInt(nextState.getId());
+	}
+}

server/src/main/java/mc/protocol/packets/client/LoginStartPacket.java

@@ -0,0 +1,43 @@
+package mc.protocol.packets.client;
+
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+import mc.protocol.State;
+import mc.protocol.io.NetByteBuf;
+import mc.protocol.packets.Packet;
+
+/**
+ * Login start packet.
+ *
+ * <p>Начало авторизации.</p>
+ *
+ * <p>Структура пакета</p>
+ * <pre>
+ * | FIELD | TYPE   | NOTES            |
+ * |-------|--------|------------------|
+ * | Name  | String | Имя/Логин игрока |
+ * </pre>
+ *
+ * @see <a href="https://wiki.vg/index.php?title=Protocol&oldid=7368#Login_Start" target="_top">Login start</a>
+ * @see State
+ */
+@NoArgsConstructor
+@Getter
+@EqualsAndHashCode
+@ToString
+public class LoginStartPacket implements Packet {
+
+	private String name;
+
+	@Override
+	public void readSelf(NetByteBuf netByteBuf) {
+		this.name = netByteBuf.readString();
+	}
+
+	@Override
+	public void writeSelf(NetByteBuf netByteBuf) {
+		netByteBuf.writeString(name);
+	}
+}

server/src/main/java/mc/protocol/packets/client/StatusServerRequest.java

@@ -0,0 +1,18 @@
+package mc.protocol.packets.client;
+
+import lombok.EqualsAndHashCode;
+import lombok.NoArgsConstructor;
+import lombok.ToString;
+import mc.protocol.packets.EmptyPacket;
+
+/**
+ * Status server packet, request.
+ *
+ * <p>Клиент запрашивает получение информации о сервере</p>
+ */
+@NoArgsConstructor
+@EqualsAndHashCode(callSuper = false)
+@ToString
+public class StatusServerRequest extends EmptyPacket {
+
+}

server/src/main/java/mc/protocol/packets/server/DisconnectPacket.java

@@ -0,0 +1,47 @@
+package mc.protocol.packets.server;
+
+import lombok.Data;
+import mc.protocol.State;
+import mc.protocol.io.NetByteBuf;
+import mc.protocol.packets.Packet;
+
+/**
+ * Diconnect packet.
+ *
+ * <p>Отключение клиента сервером с указанием причины.</p>
+ *
+ * <p>Структура пакета</p>
+ * <pre>
+ * | FIELD  | TYPE | NOTES                            |
+ * |--------|------|----------------------------------|
+ * | Reason | Text | Причина отключения. Опционально. |
+ * </pre>
+ *
+ * @see <a href="https://wiki.vg/index.php?title=Protocol&oldid=7368#Disconnect_2" target="_top">Disconnect</a>
+ * @see State
+ */
+@Data
+public class DisconnectPacket implements Packet {
+
+	/**
+	 * Причина отключения.
+	 *
+	 * <p>Пример:</p>
+	 * <pre>
+	 * {
+	 *     "text": "foo"
+	 * }
+	 * </pre>
+	 */
+	private String reason;
+
+	@Override
+	public void readSelf(NetByteBuf netByteBuf) {
+		this.reason = netByteBuf.readString();
+	}
+
+	@Override
+	public void writeSelf(NetByteBuf netByteBuf) {
+		netByteBuf.writeString(reason);
+	}
+}

server/src/main/java/mc/protocol/packets/server/StatusServerResponse.java

@@ -0,0 +1,62 @@
+package mc.protocol.packets.server;
+
+import lombok.Data;
+import mc.protocol.io.NetByteBuf;
+import mc.protocol.packets.Packet;
+
+/**
+ * Status server packet, response.
+ *
+ * <p>Информация о сервере</p>
+ *
+ * <p>Структура пакета
+ * <pre>
+ * | FIELD         | TYPE   | NOTES                                   |
+ * |---------------|--------|-----------------------------------------|
+ * | JSON Response | String | Информация о сервере в JSON формате [1] |
+ *
+ * [1] - <a href="https://wiki.vg/index.php?title=Server_List_Ping&oldid=7555#Response" target="_top">Server List Ping: Response</a>
+ * </pre></p>
+ */
+@Data
+public class StatusServerResponse implements Packet {
+
+	/**
+	 * Информация о серере в формате JSON
+	 *
+	 * <p>Пример</p>
+	 * <pre>
+	 * {
+	 *     "version": {
+	 *         "name": "1.8.7",
+	 *         "protocol": 47
+	 *     },
+	 *     "players": {
+	 *         "max": 100,
+	 *         "online": 5,
+	 *         "sample": [
+	 *             {
+	 *                 "name": "thinkofdeath",
+	 *                 "id": "4566e69f-c907-48ee-8d71-d7ba5aa00d20"
+	 *             }
+	 *         ]
+	 *     },
+	 *     "description": {
+	 *         "text": "Hello world"
+	 *     },
+	 *     "favicon": "data:image/png;base64,&lt;data&gt;"
+	 * }
+	 * </pre>
+	 */
+	private String info;
+
+	@Override
+	public void readSelf(NetByteBuf netByteBuf) {
+		info = netByteBuf.readString();
+	}
+
+	@Override
+	public void writeSelf(NetByteBuf netByteBuf) {
+		netByteBuf.writeString(info);
+	}
+}

server/src/main/java/mc/server/Main.java

@@ -0,0 +1,18 @@
+package mc.server;
+
+import lombok.extern.slf4j.Slf4j;
+import mc.server.di.DaggerNetworkComponent;
+import mc.server.di.NetworkComponent;
+import mc.server.network.Server;
+
+@Slf4j
+public class Main {
+
+	public static void main(String[] args) {
+		log.info("hello");
+
+		NetworkComponent networkComponent = DaggerNetworkComponent.create();
+		Server server = networkComponent.getServer();
+		server.bind("127.0.0.1", 25565);
+	}
+}

server/src/main/java/mc/server/di/NetworkComponent.java

@@ -0,0 +1,10 @@
+package mc.server.di;
+
+import dagger.Component;
+import mc.server.network.Server;
+
+@Component(modules = NetworkModule.class)
+public interface NetworkComponent {
+
+	Server getServer();
+}

server/src/main/java/mc/server/di/NetworkModule.java

@@ -0,0 +1,84 @@
+package mc.server.di;
+
+import dagger.Module;
+import dagger.Provides;
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelPipeline;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.socket.SocketChannel;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.handler.logging.LogLevel;
+import io.netty.handler.logging.LoggingHandler;
+import lombok.extern.slf4j.Slf4j;
+import mc.protocol.io.codec.ProtocolDecoder;
+import mc.protocol.io.codec.ProtocolEncoder;
+import mc.protocol.io.codec.ProtocolSplitter;
+import mc.server.network.Server;
+import mc.server.network.netty.handler.HandshakeHandler;
+import mc.server.network.netty.NettyServer;
+import mc.server.network.netty.handler.LoginHandler;
+import mc.server.network.netty.handler.StatusHandler;
+
+import javax.inject.Provider;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+@Module
+@Slf4j
+public class NetworkModule {
+
+	@Provides
+	Server provideServer(ServerBootstrap serverBootstrap) {
+		return new NettyServer(serverBootstrap);
+	}
+
+	@Provides
+	ServerBootstrap provideServerBootstrap(ChannelInitializer<SocketChannel> channelChannelInitializer) {
+		ServerBootstrap bootstrap = new ServerBootstrap();
+
+		bootstrap.group(new NioEventLoopGroup(1), new NioEventLoopGroup())
+				.channel(NioServerSocketChannel.class)
+				.childHandler(channelChannelInitializer);
+
+		return bootstrap;
+	}
+
+	@Provides
+	ChannelInitializer<SocketChannel> provideChannelChannelInitializer(Provider<Map<String, ChannelHandler>> channelHandlerMapProvider) {
+		return new ChannelInitializer<>() {
+			@Override
+			protected void initChannel(SocketChannel socketChannel) {
+				ChannelPipeline pipeline = socketChannel.pipeline();
+				channelHandlerMapProvider.get().forEach(pipeline::addLast);
+			}
+		};
+	}
+
+	@Provides
+	Map<String, ChannelHandler> provideChannelHandlerMap(
+			Provider<StatusHandler> statusHandlerProvider,
+			Provider<LoginHandler> loginHandlerProvider
+	) {
+		Map<String, ChannelHandler> map = new LinkedHashMap<>();
+
+		map.put("logger", new LoggingHandler(LogLevel.DEBUG));
+		map.put("protocol_splitter", new ProtocolSplitter());
+		map.put("protocol_decoder", new ProtocolDecoder(true));
+		map.put("protocol_encoder", new ProtocolEncoder());
+		map.put("handshake_handler", new HandshakeHandler(statusHandlerProvider, loginHandlerProvider));
+
+		return map;
+	}
+
+	@Provides
+	StatusHandler provideStatusHandler() {
+		return new StatusHandler();
+	}
+
+	@Provides
+	LoginHandler provideLoginHandler() {
+		return new LoginHandler();
+	}
+}

server/src/main/java/mc/server/network/Server.java

@@ -0,0 +1,6 @@
+package mc.server.network;
+
+public interface Server {
+
+	void bind(String host, int port);
+}

server/src/main/java/mc/server/network/netty/NettyServer.java

@@ -0,0 +1,26 @@
+package mc.server.network.netty;
+
+import io.netty.bootstrap.ServerBootstrap;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import mc.server.network.Server;
+
+@Slf4j
+@RequiredArgsConstructor
+public class NettyServer implements Server {
+
+	private final ServerBootstrap serverBootstrap;
+
+	@Override
+	public void bind(String host, int port) {
+		log.info("Network starting: {}:{}", host, port);
+
+		try {
+			serverBootstrap.bind(host, port).sync().channel().closeFuture().sync();
+		} catch (InterruptedException e) {
+			if (log.isTraceEnabled()) {
+				log.trace("{}: {}", e.getClass().getSimpleName(), e.getMessage(), e);
+			}
+		}
+	}
+}

server/src/main/java/mc/server/network/netty/handler/AbstractPacketHandler.java

@@ -0,0 +1,17 @@
+package mc.server.network.netty.handler;
+
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.SimpleChannelInboundHandler;
+import mc.protocol.packets.Packet;
+
+public abstract class AbstractPacketHandler<P extends Packet> extends SimpleChannelInboundHandler<Packet> {
+
+	@SuppressWarnings("unchecked")
+	@Override
+	protected void channelRead0(ChannelHandlerContext ctx, Packet msg) throws Exception {
+		channelRead1(ctx, (P) msg);
+	}
+
+	@SuppressWarnings("java:S112")
+	protected abstract void channelRead1(ChannelHandlerContext ctx, P packet) throws Exception;
+}

server/src/main/java/mc/server/network/netty/handler/HandshakeHandler.java

@@ -0,0 +1,31 @@
+package mc.server.network.netty.handler;
+
+import io.netty.channel.ChannelHandlerContext;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import mc.protocol.NetworkAttributes;
+import mc.protocol.State;
+import mc.protocol.packets.client.HandshakePacket;
+
+import javax.inject.Provider;
+
+@Slf4j
+@RequiredArgsConstructor
+public class HandshakeHandler extends AbstractPacketHandler<HandshakePacket> {
+
+	private final Provider<StatusHandler> statusHandlerProvider;
+	private final Provider<LoginHandler> loginHandlerProvider;
+
+	@Override
+	protected void channelRead1(ChannelHandlerContext ctx, HandshakePacket packet) {
+		log.info("{}", packet);
+
+		ctx.channel().attr(NetworkAttributes.STATE).set(packet.getNextState());
+
+		if (State.STATUS == packet.getNextState()) {
+			ctx.pipeline().replace("handshake_handler", "status_handler", statusHandlerProvider.get());
+		} else if (State.LOGIN == packet.getNextState()) {
+			ctx.channel().pipeline().replace("handshake_handler", "login_handler", loginHandlerProvider.get());
+		}
+	}
+}

server/src/main/java/mc/server/network/netty/handler/LoginHandler.java

@@ -0,0 +1,18 @@
+package mc.server.network.netty.handler;
+
+import io.netty.channel.ChannelHandlerContext;
+import mc.protocol.packets.client.LoginStartPacket;
+import mc.protocol.packets.server.DisconnectPacket;
+
+public class LoginHandler extends AbstractPacketHandler<LoginStartPacket> {
+
+	@Override
+	protected void channelRead1(ChannelHandlerContext ctx, LoginStartPacket packet) {
+		DisconnectPacket disconnectPacket = new DisconnectPacket();
+		disconnectPacket.setReason("{\n" +
+				"  \"text\": \"Server is not available.\"\n" +
+				"}");
+
+		ctx.channel().writeAndFlush(disconnectPacket).channel().disconnect();
+	}
+}

server/src/main/java/mc/server/network/netty/handler/StatusHandler.java

@@ -0,0 +1,33 @@
+package mc.server.network.netty.handler;
+
+import io.netty.channel.ChannelHandlerContext;
+import lombok.extern.slf4j.Slf4j;
+import mc.protocol.packets.client.StatusServerRequest;
+import mc.protocol.packets.server.StatusServerResponse;
+
+@Slf4j
+public class StatusHandler extends AbstractPacketHandler<StatusServerRequest> {
+
+	@Override
+	protected void channelRead1(ChannelHandlerContext ctx, StatusServerRequest packet) {
+		log.info("{}", packet);
+
+		StatusServerResponse response = new StatusServerResponse();
+		response.setInfo("{\n" +
+				"  \"version\": {\n" +
+				"    \"name\": \"1.12.2\",\n" +
+				"    \"protocol\": 340\n" +
+				"  },\n" +
+				"  \"players\": {\n" +
+				"    \"max\": 0,\n" +
+				"    \"online\": 0,\n" +
+				"    \"sample\": []\n" +
+				"  },\n" +
+				"  \"description\": {\n" +
+				"    \"text\": \"Hello world\"\n" +
+				"  }\n" +
+				"}");
+
+		ctx.channel().writeAndFlush(response).channel().disconnect();
+	}
+}

server/src/main/resources/logback.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <statusListener class="ch.qos.logback.core.status.NopStatusListener" />
+
+    <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
+        <layout class="ch.qos.logback.classic.PatternLayout">
+            <Pattern>%d{HH:mm:ss.SSS} %-5level [%35.35logger{34}] -- %msg%n</Pattern>
+        </layout>
+    </appender>
+
+    <root level="info">
+        <appender-ref ref="CONSOLE"/>
+    </root>
+
+    <logger name="io.netty.handler.logging.LoggingHandler" level="debug" additivity="false">
+        <appender-ref ref="CONSOLE"/>
+    </logger>
+</configuration>