Handle disconnects more gracefully.

src/main/java/io/minimum/minecraft/velocity/protocol/netty/MinecraftDecoder.java

@@ -31,7 +31,7 @@ public class MinecraftDecoder extends MessageToMessageDecoder<ByteBuf> {
         int packetId = ProtocolUtils.readVarInt(msg);
         StateRegistry.ProtocolMappings mappings = direction == ProtocolConstants.Direction.TO_CLIENT ? state.TO_CLIENT : state.TO_SERVER;
         MinecraftPacket packet = mappings.createPacket(packetId);
-        System.out.println(direction + " <- " + ByteBufUtil.hexDump(slice));
+        //System.out.println(direction + " <- " + ByteBufUtil.hexDump(slice));
         if (packet == null) {
             msg.skipBytes(msg.readableBytes());
             out.add(new PacketWrapper(null, slice));

src/main/java/io/minimum/minecraft/velocity/protocol/netty/MinecraftEncoder.java

@@ -24,7 +24,7 @@ public class MinecraftEncoder extends MessageToByteEncoder<MinecraftPacket> {
         ProtocolUtils.writeVarInt(out, packetId);
         msg.encode(out, direction, protocolVersion);
 
-        System.out.println(direction + " -> " + ByteBufUtil.hexDump(out));
+        //System.out.println(direction + " -> " + ByteBufUtil.hexDump(out));
     }
 
     public int getProtocolVersion() {

src/main/java/io/minimum/minecraft/velocity/proxy/ConnectedPlayer.java

@@ -50,4 +50,8 @@ public class ConnectedPlayer {
             // TODO
         }
     }
+
+    public void setConnectedServer(ServerConnection serverConnection) {
+        this.connectedServer = serverConnection;
+    }
 }

src/main/java/io/minimum/minecraft/velocity/proxy/InboundMinecraftConnection.java

@@ -10,11 +10,13 @@ import io.minimum.minecraft.velocity.protocol.packets.Handshake;
 import io.minimum.minecraft.velocity.protocol.packets.ServerLoginSuccess;
 import io.minimum.minecraft.velocity.proxy.handler.HandshakeSessionHandler;
 import io.minimum.minecraft.velocity.proxy.handler.LoginSessionHandler;
+import io.minimum.minecraft.velocity.proxy.handler.PlaySessionHandler;
 import io.minimum.minecraft.velocity.proxy.handler.StatusSessionHandler;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.util.AttributeKey;
+import net.kyori.text.TextComponent;
 
 import java.net.InetSocketAddress;
 import java.util.Optional;
@@ -43,7 +45,7 @@ public class InboundMinecraftConnection {
 
     public void closeWith(Object msg) {
         ensureOpen();
-        closed = true;
+        teardown();
         channel.writeAndFlush(msg).addListener(new ChannelFutureListener() {
             @Override
             public void operationComplete(ChannelFuture future) throws Exception {
@@ -54,8 +56,8 @@ public class InboundMinecraftConnection {
 
     public void close() {
         ensureOpen();
+        teardown();
         channel.close();
-        closed = true;
     }
 
     public MinecraftSessionHandler getSessionHandler() {
@@ -95,6 +97,9 @@ public class InboundMinecraftConnection {
 
     public void teardown() {
         closed = true;
+        if (connectedPlayer != null && connectedPlayer.getConnectedServer() != null) {
+            connectedPlayer.getConnectedServer().disconnect();
+        }
     }
 
     public boolean isClosed() {
@@ -114,6 +119,7 @@ public class InboundMinecraftConnection {
         ConnectedPlayer player = new ConnectedPlayer(success.getUsername(), success.getUuid(), this);
         ServerInfo info = new ServerInfo("test", new InetSocketAddress("127.0.0.1", 25565));
         ServerConnection connection = new ServerConnection(info, player, VelocityServer.getServer());
+        sessionHandler = new PlaySessionHandler(player, connection);
         connection.connect();
     }
 }

src/main/java/io/minimum/minecraft/velocity/proxy/ServerConnection.java

@@ -11,7 +11,9 @@ import io.minimum.minecraft.velocity.protocol.packets.Disconnect;
 import io.minimum.minecraft.velocity.protocol.packets.Handshake;
 import io.minimum.minecraft.velocity.protocol.packets.ServerLogin;
 import io.minimum.minecraft.velocity.protocol.packets.ServerLoginSuccess;
+import io.netty.buffer.ByteBuf;
 import io.netty.channel.*;
+import net.kyori.text.TextComponent;
 
 public class ServerConnection {
     private Channel channel;
@@ -45,6 +47,18 @@ public class ServerConnection {
                 });
     }
 
+    public void disconnect() {
+        channel.close();
+        channel = null;
+    }
+
+    public void forward(ByteBuf buf) {
+        if (registry != StateRegistry.PLAY) {
+            throw new IllegalStateException("Not accepting player information until PLAY state");
+        }
+        channel.writeAndFlush(buf.retain());
+    }
+
     private class StateBasedInterceptor extends ChannelInboundHandlerAdapter {
         @Override
         public void channelActive(ChannelHandlerContext ctx) throws Exception {
@@ -66,6 +80,13 @@ public class ServerConnection {
 
         @Override
         public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+            if (proxyPlayer.getConnection().isClosed()) {
+                // The upstream connection is closed, but we didn't forward that on for some reason. Close the connection
+                // here.
+                ctx.close();
+                return;
+            }
+
             if (msg instanceof PacketWrapper) {
                 PacketWrapper pw = (PacketWrapper) msg;
                 try {
@@ -102,6 +123,7 @@ public class ServerConnection {
                 // the player has been logged on.
                 System.out.println("Player connected to remote server");
                 setRegistry(StateRegistry.PLAY);
+                proxyPlayer.setConnectedServer(ServerConnection.this);
             }
         }
     }

src/main/java/io/minimum/minecraft/velocity/proxy/handler/PlaySessionHandler.java

@@ -1,10 +1,20 @@
 package io.minimum.minecraft.velocity.proxy.handler;
 
 import io.minimum.minecraft.velocity.protocol.MinecraftPacket;
+import io.minimum.minecraft.velocity.proxy.ConnectedPlayer;
 import io.minimum.minecraft.velocity.proxy.MinecraftSessionHandler;
+import io.minimum.minecraft.velocity.proxy.ServerConnection;
 import io.netty.buffer.ByteBuf;
 
 public class PlaySessionHandler implements MinecraftSessionHandler {
+    private final ConnectedPlayer player;
+    private final ServerConnection connection;
+
+    public PlaySessionHandler(ConnectedPlayer player, ServerConnection connection) {
+        this.player = player;
+        this.connection = connection;
+    }
+
     @Override
     public void handle(MinecraftPacket packet) {
 
@@ -12,6 +22,6 @@ public class PlaySessionHandler implements MinecraftSessionHandler {
 
     @Override
     public void handleUnknown(ByteBuf buf) {
-
+        connection.forward(buf);
     }
 }