запрет входа на сервер

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

@@ -7,7 +7,9 @@ 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;
@@ -24,6 +26,12 @@ public enum State {
 			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

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);
+	}
+}

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);
+	}
+}

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

@@ -16,9 +16,10 @@ 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.HandshakeHandler;
+import mc.server.network.netty.handler.HandshakeHandler;
 import mc.server.network.netty.NettyServer;
-import mc.server.network.netty.StatusHandler;
+import mc.server.network.netty.handler.LoginHandler;
+import mc.server.network.netty.handler.StatusHandler;
 
 import javax.inject.Provider;
 import java.util.LinkedHashMap;
@@ -56,14 +57,17 @@ public class NetworkModule {
 	}
 
 	@Provides
-	Map<String, ChannelHandler> provideChannelHandlerMap(Provider<StatusHandler> statusHandlerProvider) {
+	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));
+		map.put("handshake_handler", new HandshakeHandler(statusHandlerProvider, loginHandlerProvider));
 
 		return map;
 	}
@@ -72,4 +76,9 @@ public class NetworkModule {
 	StatusHandler provideStatusHandler() {
 		return new StatusHandler();
 	}
+
+	@Provides
+	LoginHandler provideLoginHandler() {
+		return new LoginHandler();
+	}
 }

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

@@ -1,4 +1,4 @@
-package mc.server.network.netty;
+package mc.server.network.netty.handler;
 
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;

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

@@ -1,9 +1,10 @@
-package mc.server.network.netty;
+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;
@@ -13,12 +14,18 @@ import javax.inject.Provider;
 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());
-		ctx.pipeline().replace("handshake_handler", "status_handler", statusHandlerProvider.get());
+
+		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());
+		}
 	}
 }

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();
+	}
+}

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

@@ -1,4 +1,4 @@
-package mc.server.network.netty;
+package mc.server.network.netty.handler;
 
 import io.netty.channel.ChannelHandlerContext;
 import lombok.extern.slf4j.Slf4j;