[Ready]Replace deprecated KCP library (#1237)

* Replace deprecated KCP library

support get srtt

Waiting server to establish

logicThread

Print Bad Package Information

Avoid orphan data

improve conv id security

* Improve connection subsequence

src/main/java/emu/grasscutter/netty/KcpChannel.java

-package emu.grasscutter.netty;
-
-import emu.grasscutter.Grasscutter;
-import io.jpower.kcp.netty.UkcpChannel;
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufUtil;
-import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelInboundHandlerAdapter;
-
-public abstract class KcpChannel extends ChannelInboundHandlerAdapter {
-	private UkcpChannel kcpChannel;
-	private ChannelHandlerContext ctx;
-	private boolean isActive;
-	
-    public UkcpChannel getChannel() {
-		return kcpChannel;
-	}
-    
-    public boolean isActive() {
-    	return this.isActive;
-    }
-
-	@Override
-    public void channelActive(ChannelHandlerContext ctx) throws Exception {
-        this.kcpChannel = (UkcpChannel) ctx.channel();
-        this.ctx = ctx;
-        this.isActive = true;
-       
-        this.onConnect();
-    }
-	
-	@Override
-    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
-		this.isActive = false;
-		
-        this.onDisconnect();
-    }
-
-	@Override
-    public void channelRead(ChannelHandlerContext ctx, Object msg) {
-    	ByteBuf data = (ByteBuf) msg;
-    	onMessage(ctx, data);
-    }
-
-    @Override
-    public void channelReadComplete(ChannelHandlerContext ctx) {
-        ctx.flush();
-    }
-    
-    @Override
-    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
-        cause.printStackTrace();
-        close();
-    }
-
-    protected void send(byte[] data) {
-    	if (!isActive()) {
-    		return;
-    	}
-    	ByteBuf packet = Unpooled.wrappedBuffer(data);
-    	kcpChannel.writeAndFlush(packet);
-    }
-    
-    public void close() {
-    	if (getChannel() != null) {
-    		getChannel().close();
-    	}
-    }
-
-    /*
-    protected void logPacket(ByteBuffer buf) {
-		ByteBuf b = Unpooled.wrappedBuffer(buf.array());
-    	logPacket(b);
-    } 
-    */
-    
-    protected void logPacket(ByteBuf buf) {
-    	Grasscutter.getLogger().info("Received: \n" + ByteBufUtil.prettyHexDump(buf));
-    }
-    
-    // Events
-
-	protected abstract void onConnect();
-
-    protected abstract void onDisconnect();
-    
-    public abstract void onMessage(ChannelHandlerContext ctx, ByteBuf data);
-}

src/main/java/emu/grasscutter/netty/KcpHandshaker.java

-package emu.grasscutter.netty;
-
-import java.net.SocketAddress;
-import java.nio.channels.SelectableChannel;
-import java.util.List;
-
-import io.netty.channel.Channel;
-import io.netty.channel.ChannelConfig;
-import io.netty.channel.ChannelMetadata;
-import io.netty.channel.ChannelOutboundBuffer;
-import io.netty.channel.nio.AbstractNioMessageChannel;
-
-public class KcpHandshaker extends AbstractNioMessageChannel {
-
-	protected KcpHandshaker(Channel parent, SelectableChannel ch, int readInterestOp) {
-		super(parent, ch, readInterestOp);
-	}
-
-	@Override
-	public ChannelConfig config() {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	@Override
-	public boolean isActive() {
-		// TODO Auto-generated method stub
-		return false;
-	}
-
-	@Override
-	public ChannelMetadata metadata() {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	@Override
-	protected int doReadMessages(List<Object> buf) throws Exception {
-		// TODO Auto-generated method stub
-		return 0;
-	}
-
-	@Override
-	protected boolean doWriteMessage(Object msg, ChannelOutboundBuffer in) throws Exception {
-		// TODO Auto-generated method stub
-		return false;
-	}
-
-	@Override
-	protected boolean doConnect(SocketAddress remoteAddress, SocketAddress localAddress) throws Exception {
-		// TODO Auto-generated method stub
-		return false;
-	}
-
-	@Override
-	protected void doFinishConnect() throws Exception {
-		// TODO Auto-generated method stub
-		
-	}
-
-	@Override
-	protected SocketAddress localAddress0() {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	@Override
-	protected SocketAddress remoteAddress0() {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	@Override
-	protected void doBind(SocketAddress localAddress) throws Exception {
-		// TODO Auto-generated method stub
-		
-	}
-
-	@Override
-	protected void doDisconnect() throws Exception {
-		// TODO Auto-generated method stub
-		
-	}
-
-}

src/main/java/emu/grasscutter/netty/KcpServer.java

-package emu.grasscutter.netty;
-
-import java.net.InetSocketAddress;
-
-import emu.grasscutter.Grasscutter;
-import io.jpower.kcp.netty.ChannelOptionHelper;
-import io.jpower.kcp.netty.UkcpChannelOption;
-import io.jpower.kcp.netty.UkcpServerChannel;
-import io.netty.bootstrap.UkcpServerBootstrap;
-import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
-
-@SuppressWarnings("rawtypes")
-public class KcpServer extends Thread {
-	private EventLoopGroup group;
-	private UkcpServerBootstrap bootstrap;
-	
-	private ChannelInitializer serverInitializer;
-	private InetSocketAddress address;
-	 
-	public KcpServer(InetSocketAddress address) {
-    	this.address = address;
-    	this.setName("Netty Server Thread");
-    }
-	
-	public InetSocketAddress getAddress() {
-    	return this.address;
-    }
-
-    public ChannelInitializer getServerInitializer() {
-		return serverInitializer;
-	}
-
-	public void setServerInitializer(ChannelInitializer serverInitializer) {
-		this.serverInitializer = serverInitializer;
-	}
-
-	@Override
-	public void run() {
-		if (getServerInitializer() == null) {
-			this.setServerInitializer(new KcpServerInitializer());
-		}
-		
-        try {
-        	group = new NioEventLoopGroup();
-            bootstrap = new UkcpServerBootstrap();
-            bootstrap.group(group)
-                    .channel(UkcpServerChannel.class)
-                    .childHandler(this.getServerInitializer());
-            ChannelOptionHelper
-            	.nodelay(bootstrap, true, 20, 2, true)
-            	.childOption(UkcpChannelOption.UKCP_MTU, 1200);
-            
-            // Start handler
-            this.onStart();
-            
-            // Start the server.
-            ChannelFuture f = bootstrap.bind(getAddress()).sync();
-            
-            // Start finish handler
-            this.onStartFinish();
-
-            // Wait until the server socket is closed.
-            f.channel().closeFuture().sync();
-        } catch (Exception exception) {
-			Grasscutter.getLogger().error("Unable to start game server.", exception);
-		} finally {
-        	// Close
-			finish();
-        }
-	}
-	
-	public void onStart() {
-
-	}
-
-	public void onStartFinish() {
-
-	}
-	
-	private void finish() {
-		try {
-			group.shutdownGracefully();
-		} catch (Exception e) {
-			
-		}
-		Grasscutter.getLogger().info("Game Server closed");
-	}
-}
-
-

src/main/java/emu/grasscutter/netty/KcpServerInitializer.java

-package emu.grasscutter.netty;
-
-import io.jpower.kcp.netty.UkcpChannel;
-import io.netty.channel.ChannelInitializer;
-import io.netty.channel.ChannelPipeline;
-
-@SuppressWarnings("unused")
-public class KcpServerInitializer extends ChannelInitializer<UkcpChannel> {
-	
-	@Override
-	protected void initChannel(UkcpChannel ch) throws Exception {
-		ChannelPipeline pipeline = ch.pipeline();
-	}
-
-}

src/main/java/emu/grasscutter/server/game/GameServer.java

@@ -21,13 +21,13 @@ import emu.grasscutter.game.tower.TowerScheduleManager;
 import emu.grasscutter.game.world.World;
 import emu.grasscutter.net.packet.PacketHandler;
 import emu.grasscutter.net.proto.SocialDetailOuterClass.SocialDetail;
-import emu.grasscutter.netty.KcpServer;
 import emu.grasscutter.server.event.types.ServerEvent;
 import emu.grasscutter.server.event.game.ServerTickEvent;
 import emu.grasscutter.server.event.internal.ServerStartEvent;
 import emu.grasscutter.server.event.internal.ServerStopEvent;
 import emu.grasscutter.task.TaskMap;
-import emu.grasscutter.BuildConfig;
+import kcp.highway.ChannelConfig;
+import kcp.highway.KcpServer;
 
 import java.net.InetSocketAddress;
 import java.time.OffsetDateTime;
@@ -60,7 +60,7 @@ public final class GameServer extends KcpServer {
 	private final TowerScheduleManager towerScheduleManager;
 
 	private static InetSocketAddress getAdapterInetSocketAddress(){
-		InetSocketAddress inetSocketAddress = null;
+		InetSocketAddress inetSocketAddress;
 		if(GAME_INFO.bindAddress.equals("")){
 			inetSocketAddress=new InetSocketAddress(GAME_INFO.bindPort);
 		}else{
@@ -75,9 +75,17 @@ public final class GameServer extends KcpServer {
 		this(getAdapterInetSocketAddress());
 	}
 	public GameServer(InetSocketAddress address) {
-		super(address);
+		ChannelConfig channelConfig = new ChannelConfig();
+		channelConfig.nodelay(true,40,2,true);
+		channelConfig.setMtu(1400);
+		channelConfig.setSndwnd(256);
+		channelConfig.setRcvwnd(256);
+		channelConfig.setTimeoutMillis(30*1000);//30s
+		channelConfig.setUseConvChannel(true);
+		channelConfig.setAckNoDelay(false);
+
+		this.init(GameSessionManager.getListener(),channelConfig,address);
 
-		this.setServerInitializer(new GameServerInitializer(this));
 		this.address = address;
 		this.packetHandler = new GameServerPacketHandler(PacketHandler.class);
 		this.questHandler = new ServerQuestHandler();
@@ -96,6 +104,7 @@ public final class GameServer extends KcpServer {
 		this.expeditionManager = new ExpeditionManager(this);
 		this.combineManger = new CombineManger(this);
 		this.towerScheduleManager = new TowerScheduleManager(this);
+
 		// Hook into shutdown event.
 		Runtime.getRuntime().addShutdownHook(new Thread(this::onServerShutdown));
 	}
@@ -164,6 +173,7 @@ public final class GameServer extends KcpServer {
 		return towerScheduleManager;
 	}
 
+
 	public TaskMap getTaskMap() {
 		return this.taskMap;
 	}
@@ -220,23 +230,23 @@ public final class GameServer extends KcpServer {
 		}
 		return DatabaseHelper.getAccountByName(username);
 	}
-	
-	public void onTick() throws Exception {
+
+	public synchronized void onTick(){
 		Iterator<World> it = this.getWorlds().iterator();
 		while (it.hasNext()) {
 			World world = it.next();
-			
+
 			if (world.getPlayerCount() == 0) {
 				it.remove();
 			}
-			
+
 			world.onTick();
 		}
-		
+
 		for (Player player : this.getPlayers().values()) {
 			player.onTick();
 		}
-  
+
 		ServerTickEvent event = new ServerTickEvent(); event.call();
 	}
 	
@@ -249,8 +259,7 @@ public final class GameServer extends KcpServer {
 		
 	}
 
-	@Override
-	public synchronized void start() {
+	public void start() {
 		// Schedule game loop.
 		Timer gameLoop = new Timer();
 		gameLoop.scheduleAtFixedRate(new TimerTask() {
@@ -263,24 +272,19 @@ public final class GameServer extends KcpServer {
 				}
 			}
 		}, new Date(), 1000L);
-
-		super.start();
-	}
-
-	@Override
-	public void onStartFinish() {
 		Grasscutter.getLogger().info(translate("messages.status.free_software"));
 		Grasscutter.getLogger().info(translate("messages.game.port_bind", Integer.toString(address.getPort())));
-		ServerStartEvent event = new ServerStartEvent(ServerEvent.Type.GAME, OffsetDateTime.now()); event.call();
+		ServerStartEvent event = new ServerStartEvent(ServerEvent.Type.GAME, OffsetDateTime.now());
+		event.call();
 	}
-	
+
 	public void onServerShutdown() {
 		ServerStopEvent event = new ServerStopEvent(ServerEvent.Type.GAME, OffsetDateTime.now()); event.call();
 
 		// Kick and save all players
 		List<Player> list = new ArrayList<>(this.getPlayers().size());
 		list.addAll(this.getPlayers().values());
-		
+
 		for (Player player : list) {
 			player.getSession().close();
 		}

src/main/java/emu/grasscutter/server/game/GameServerInitializer.java

-package emu.grasscutter.server.game;
-
-import emu.grasscutter.netty.KcpServerInitializer;
-import io.jpower.kcp.netty.UkcpChannel;
-import io.netty.channel.ChannelPipeline;
-
-public class GameServerInitializer extends KcpServerInitializer {
-	private GameServer server;
-	
-	public GameServerInitializer(GameServer server) {
-		this.server = server;
-	}
-	
-    @Override
-    protected void initChannel(UkcpChannel ch) throws Exception {
-        ChannelPipeline pipeline=null;
-        if(ch!=null){
-            pipeline = ch.pipeline();
-        }
-        new GameSession(server,pipeline);
-    }
-}

src/main/java/emu/grasscutter/server/game/GameSession.java

@@ -2,9 +2,6 @@ package emu.grasscutter.server.game;
 
 import java.io.File;
 import java.net.InetSocketAddress;
-import java.nio.ByteBuffer;
-import java.util.Iterator;
-import java.util.Map;
 import java.util.Set;
 
 import emu.grasscutter.Grasscutter;
@@ -14,23 +11,19 @@ import emu.grasscutter.game.player.Player;
 import emu.grasscutter.net.packet.BasePacket;
 import emu.grasscutter.net.packet.PacketOpcodes;
 import emu.grasscutter.net.packet.PacketOpcodesUtil;
-import emu.grasscutter.netty.KcpChannel;
 import emu.grasscutter.server.event.game.SendPacketEvent;
 import emu.grasscutter.utils.Crypto;
 import emu.grasscutter.utils.FileUtils;
 import emu.grasscutter.utils.Utils;
-import io.jpower.kcp.netty.UkcpChannel;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelPipeline;
-
-import static emu.grasscutter.utils.Language.translate;
 import static emu.grasscutter.Configuration.*;
+import static emu.grasscutter.utils.Language.translate;
 
-public class GameSession extends KcpChannel {
+public class GameSession implements GameSessionManager.KcpChannel {
 	private final GameServer server;
-	
+	private GameSessionManager.KcpTunnel tunnel;
+
 	private Account account;
 	private Player player;
 	
@@ -41,29 +34,10 @@ public class GameSession extends KcpChannel {
 	private long lastPingTime;
 	private int lastClientSeq = 10;
 
-	private final ChannelPipeline pipeline;
-	@Override
-	public void close() {
-		setState(SessionState.INACTIVE);
-		//send disconnection pack in case of reconnection
-		try {
-			send(new BasePacket(PacketOpcodes.ServerDisconnectClientNotify));
-		}catch (Throwable ignore){
-
-		}
-		super.close();
-	}
 	public GameSession(GameServer server) {
-		this(server,null);
-	}
-	public GameSession(GameServer server, ChannelPipeline pipeline) {
 		this.server = server;
 		this.state = SessionState.WAITING_FOR_TOKEN;
 		this.lastPingTime = System.currentTimeMillis();
-		this.pipeline = pipeline;
-		if(pipeline!=null) {
-			pipeline.addLast(this);
-		}
 	}
 	
 	public GameServer getServer() {
@@ -71,10 +45,11 @@ public class GameSession extends KcpChannel {
 	}
 	
 	public InetSocketAddress getAddress() {
-		if (this.getChannel() == null) {
+		try{
+			return tunnel.getAddress();
+		}catch (Throwable ignore){
 			return null;
 		}
-		return this.getChannel().remoteAddress();
 	}
 
 	public boolean useSecretKey() {
@@ -135,37 +110,7 @@ public class GameSession extends KcpChannel {
 	public int getNextClientSequence() {
 		return ++lastClientSeq;
 	}
-	
-	@Override
-	protected void onConnect() {
-		Grasscutter.getLogger().info(translate("messages.game.connect", this.getAddress().getHostString().toLowerCase()));
-	}
-
-	@Override
-	protected synchronized void onDisconnect() { // Synchronize so we don't add character at the same time.
-		Grasscutter.getLogger().info(translate("messages.game.disconnect", this.getAddress().getHostString().toLowerCase()));
-
-		// Set state so no more packets can be handled
-		this.setState(SessionState.INACTIVE);
-
-		// Save after disconnecting
-		if (this.isLoggedIn()) {
-			Player player = getPlayer();
-			// Call logout event.
-			player.onLogout();
-		}
-		try {
-			pipeline.remove(this);
-		} catch (Throwable ignore) {
 
-		}
-	}
-	
-    protected void logPacket(ByteBuffer buf) {
-		ByteBuf b = Unpooled.wrappedBuffer(buf.array());
-    	logPacket(b);
-    }
-    
     public void replayPacket(int opcode, String name) {
     	String filePath = PACKET(name);
 		File p = new File(filePath);
@@ -200,13 +145,16 @@ public class GameSession extends KcpChannel {
     	
     	// Log
     	if (SERVER.debugLevel == ServerDebugMode.ALL) {
-    		logPacket(packet);
+			if (!loopPacket.contains(packet.getOpcode())) {
+				Grasscutter.getLogger().info("SEND: " + PacketOpcodesUtil.getOpcodeName(packet.getOpcode()) + " (" + packet.getOpcode() + ")");
+				System.out.println(Utils.bytesToHex(packet.getData()));
+			}
     	}
-		
 		// Invoke event.
 		SendPacketEvent event = new SendPacketEvent(this, packet); event.call();
-    	if(!event.isCanceled()) // If event is not cancelled, continue.
-			this.send(event.getPacket().build());
+    	if(!event.isCanceled()) { // If event is not cancelled, continue.
+			tunnel.writeData(event.getPacket().build());
+		}
     }
     
 	private static final Set<Integer> loopPacket = Set.of(
@@ -217,78 +165,104 @@ public class GameSession extends KcpChannel {
 			PacketOpcodes.QueryPathReq
 	);
 
-    private void logPacket(BasePacket packet) {
-		if (!loopPacket.contains(packet.getOpcode())) {
-			Grasscutter.getLogger().info("SEND: " + PacketOpcodesUtil.getOpcodeName(packet.getOpcode()) + " (" + packet.getOpcode() + ")");
-			System.out.println(Utils.bytesToHex(packet.getData()));
-		}
-    }
+	@Override
+	public void onConnected(GameSessionManager.KcpTunnel tunnel) {
+		this.tunnel = tunnel;
+		Grasscutter.getLogger().info(translate("messages.game.connect", this.getAddress().toString()));
+	}
+
 
 	@Override
-	public void onMessage(ChannelHandlerContext ctx, ByteBuf data) {
+	public void handleReceive(byte[] bytes) {
 		// Decrypt and turn back into a packet
-		byte[] byteData = Utils.byteBufToArray(data);
-		Crypto.xor(byteData, useSecretKey() ? Crypto.ENCRYPT_KEY : Crypto.DISPATCH_KEY);
-		ByteBuf packet = Unpooled.wrappedBuffer(byteData);
-		
+		Crypto.xor(bytes, useSecretKey() ? Crypto.ENCRYPT_KEY : Crypto.DISPATCH_KEY);
+		ByteBuf packet = Unpooled.wrappedBuffer(bytes);
+
 		// Log
 		//logPacket(packet);
-		
 		// Handle
 		try {
+			boolean allDebug = SERVER.debugLevel == ServerDebugMode.ALL;
 			while (packet.readableBytes() > 0) {
 				// Length
 				if (packet.readableBytes() < 12) {
 					return;
 				}
-				
 				// Packet sanity check
 				int const1 = packet.readShort();
 				if (const1 != 17767) {
+					if(allDebug){
+						Grasscutter.getLogger().error("Bad Data Package Received: got {} ,expect 17767",const1);
+					}
 					return; // Bad packet
 				}
-
 				// Data
 				int opcode = packet.readShort();
 				int headerLength = packet.readShort();
 				int payloadLength = packet.readInt();
-				
 				byte[] header = new byte[headerLength];
 				byte[] payload = new byte[payloadLength];
-				
+
 				packet.readBytes(header);
 				packet.readBytes(payload);
-				
 				// Sanity check #2
 				int const2 = packet.readShort();
 				if (const2 != -30293) {
+					if(allDebug){
+						Grasscutter.getLogger().error("Bad Data Package Received: got {} ,expect -30293",const2);
+					}
 					return; // Bad packet
 				}
-				
 				// Log packet
-				if (SERVER.debugLevel == ServerDebugMode.ALL) {
+				if (allDebug) {
 					if (!loopPacket.contains(opcode)) {
 						Grasscutter.getLogger().info("RECV: " + PacketOpcodesUtil.getOpcodeName(opcode) + " (" + opcode + ")");
 						System.out.println(Utils.bytesToHex(payload));
 					}
 				}
-				
 				// Handle
 				getServer().getPacketHandler().handle(this, opcode, header, payload);
 			}
 		} catch (Exception e) {
 			e.printStackTrace();
 		} finally {
-			data.release();
+			//byteBuf.release(); //Needn't
 			packet.release();
 		}
 	}
-	
+
+	@Override
+	public void handleClose() {
+		setState(SessionState.INACTIVE);
+		//send disconnection pack in case of reconnection
+		Grasscutter.getLogger().info(translate("messages.game.disconnect", this.getAddress().toString()));
+		// Save after disconnecting
+		if (this.isLoggedIn()) {
+			Player player = getPlayer();
+			// Call logout event.
+			player.onLogout();
+		}
+		try {
+			send(new BasePacket(PacketOpcodes.ServerDisconnectClientNotify));
+		}catch (Throwable ignore){
+			Grasscutter.getLogger().warn("closing {} error",getAddress().getAddress().getHostAddress());
+		}
+		tunnel = null;
+	}
+
+	public void close() {
+		tunnel.close();
+	}
+
+	public boolean isActive() {
+		return getState() == SessionState.ACTIVE;
+	}
+
 	public enum SessionState {
 		INACTIVE,
 		WAITING_FOR_TOKEN,
 		WAITING_FOR_LOGIN,
 		PICKING_CHARACTER,
-		ACTIVE;
+		ACTIVE
 	}
 }

src/main/java/emu/grasscutter/server/game/GameSessionManager.java

+package emu.grasscutter.server.game;
+
+import java.net.InetSocketAddress;
+import java.util.concurrent.ConcurrentHashMap;
+
+import emu.grasscutter.Grasscutter;
+import emu.grasscutter.utils.Crypto;
+import emu.grasscutter.utils.Utils;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.DefaultEventLoop;
+import kcp.highway.KcpListener;
+import kcp.highway.Ukcp;
+
+public class GameSessionManager {
+    private static final DefaultEventLoop logicThread = new DefaultEventLoop();
+    private static final ConcurrentHashMap<Ukcp,GameSession> sessions = new ConcurrentHashMap<>();
+    private static final KcpListener listener = new KcpListener(){
+        @Override
+        public void onConnected(Ukcp ukcp) {
+            int times = 0;
+            GameServer server = Grasscutter.getGameServer();
+            while (server==null){//Waiting server to establish
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                    ukcp.close();
+                    return;
+                }
+                if(times++>5){
+                    Grasscutter.getLogger().error("Service is not available!");
+                    ukcp.close();
+                    return;
+                }
+                server = Grasscutter.getGameServer();
+            }
+            GameSession conversation = new GameSession(server);
+            conversation.onConnected(new KcpTunnel(){
+                @Override
+                public InetSocketAddress getAddress() {
+                    return ukcp.user().getRemoteAddress();
+                }
+
+                @Override
+                public void writeData(byte[] bytes) {
+                    ByteBuf buf = Unpooled.wrappedBuffer(bytes);
+                    ukcp.write(buf);
+                    buf.release();
+                }
+
+                @Override
+                public void close() {
+                    ukcp.close();
+                }
+
+                @Override
+                public int getSrtt() {
+                    return ukcp.srtt();
+                }
+            });
+            sessions.put(ukcp,conversation);
+        }
+
+        @Override
+        public void handleReceive(ByteBuf buf, Ukcp kcp) {
+            byte[] byteData = Utils.byteBufToArray(buf);
+            logicThread.execute(() -> {
+                try {
+                    GameSession conversation = sessions.get(kcp);
+                    if(conversation!=null) {
+                        conversation.handleReceive(byteData);
+                    }
+                }catch (Exception e){
+                    e.printStackTrace();
+                }
+            });
+        }
+
+        @Override
+        public void handleException(Throwable ex, Ukcp ukcp) {
+
+        }
+
+        @Override
+        public void handleClose(Ukcp ukcp) {
+            GameSession conversation = sessions.get(ukcp);
+            if(conversation!=null) {
+                conversation.handleClose();
+                sessions.remove(ukcp);
+            }
+        }
+    };
+
+    public static KcpListener getListener() {
+        return listener;
+    }
+
+    interface KcpTunnel{
+        InetSocketAddress getAddress();
+        void writeData(byte[] bytes);
+        void close();
+        int getSrtt();
+    }
+    interface KcpChannel{
+        void onConnected(KcpTunnel tunnel);
+        void handleClose();
+        void handleReceive(byte[] bytes);
+    }
+}