Paper/CraftBukkit-Patches/0024-Netty.patch

From 13da8d1098ec4326777b56ae4510a7bdee4e5de2 Mon Sep 17 00:00:00 2001
From: md_5 <md_5@live.com.au>
Date: Tue, 2 Jul 2013 09:06:29 +1000
Subject: [PATCH] Netty


diff --git a/pom.xml b/pom.xml
index afe0225..4cffec7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -112,6 +112,21 @@
       <artifactId>trove4j</artifactId>
       <version>3.0.3</version>
     </dependency>
+    <dependency>
+      <groupId>io.netty</groupId>
+      <artifactId>netty-codec</artifactId>
+      <version>4.0.0.CR9</version>
+    </dependency>
+    <dependency>
+      <groupId>io.netty</groupId>
+      <artifactId>netty-handler</artifactId>
+      <version>4.0.0.CR9</version>
+    </dependency>
+    <dependency>
+      <groupId>org.javassist</groupId>
+      <artifactId>javassist</artifactId>
+      <version>3.18.0-GA</version>
+    </dependency>
   </dependencies>
 
   <!-- This builds a completely 'ready to start' jar with all dependencies inside -->
diff --git a/src/main/java/net/minecraft/server/DedicatedServer.java b/src/main/java/net/minecraft/server/DedicatedServer.java
index 6fe33d0..fa02974 100644
--- a/src/main/java/net/minecraft/server/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/DedicatedServer.java
@@ -100,7 +100,11 @@ public class DedicatedServer extends MinecraftServer implements IMinecraftServer
         this.getLogger().info("Starting Minecraft server on " + (this.getServerIp().length() == 0 ? "*" : this.getServerIp()) + ":" + this.I());
 
         try {
-            this.s = new DedicatedServerConnection(this, inetaddress, this.I());
+            // Spigot start
+            this.s = ( org.spigotmc.SpigotConfig.listeners.get( 0 ).netty )
+                    ? new org.spigotmc.netty.NettyServerConnection( this, inetaddress, this.I() )
+                    : new DedicatedServerConnection( this, inetaddress, this.I() );
+            // Spigot end
         } catch (Throwable ioexception) { // CraftBukkit - IOException -> Throwable
             this.getLogger().warning("**** FAILED TO BIND TO PORT!");
             this.getLogger().warning("The exception was: {0}", new Object[] { ioexception.toString()});
diff --git a/src/main/java/net/minecraft/server/INetworkManager.java b/src/main/java/net/minecraft/server/INetworkManager.java
new file mode 100644
index 0000000..6fcc5d7
--- /dev/null
+++ b/src/main/java/net/minecraft/server/INetworkManager.java
@@ -0,0 +1,26 @@
+package net.minecraft.server;
+
+import java.net.SocketAddress;
+
+public interface INetworkManager {
+
+    void a(Connection connection);
+
+    void queue(Packet packet);
+
+    void a();
+
+    void b();
+
+    SocketAddress getSocketAddress();
+
+    void d();
+
+    int e();
+
+    void a(String s, Object... aobject);
+    
+    java.net.Socket getSocket(); // Spigot
+    
+    void setSocketAddress(java.net.SocketAddress address); // Spigot
+}
diff --git a/src/main/java/net/minecraft/server/NetworkManager.java b/src/main/java/net/minecraft/server/NetworkManager.java
index a2bdfa3..fd6acab 100644
--- a/src/main/java/net/minecraft/server/NetworkManager.java
+++ b/src/main/java/net/minecraft/server/NetworkManager.java
@@ -27,7 +27,7 @@ public class NetworkManager implements INetworkManager {
     private final Object h = new Object();
     private final IConsoleLogManager i;
     public Socket socket; // CraftBukkit - private -> public
-    private final SocketAddress k;
+    private SocketAddress k; // Spigot - remove final
     private volatile DataInputStream input;
     private volatile DataOutputStream output;
     private volatile boolean n = true;
@@ -374,4 +374,6 @@ public class NetworkManager implements INetworkManager {
     static Thread h(NetworkManager networkmanager) {
         return networkmanager.u;
     }
+
+    public void setSocketAddress(SocketAddress address) { k = address; } // Spigot
 }
diff --git a/src/main/java/net/minecraft/server/PendingConnection.java b/src/main/java/net/minecraft/server/PendingConnection.java
index c9e187e..b433c60 100644
--- a/src/main/java/net/minecraft/server/PendingConnection.java
+++ b/src/main/java/net/minecraft/server/PendingConnection.java
@@ -16,7 +16,7 @@ public class PendingConnection extends Connection {
     private static Random random = new Random();
     private byte[] d;
     private final MinecraftServer server;
-    public final NetworkManager networkManager;
+    public final INetworkManager networkManager;
     public boolean b;
     private int f;
     private String g;
@@ -26,10 +26,15 @@ public class PendingConnection extends Connection {
     private SecretKey k;
     public String hostname = ""; // CraftBukkit - add field
 
+    public PendingConnection(MinecraftServer minecraftserver, org.spigotmc.netty.NettyNetworkManager networkManager) {
+        this.server = minecraftserver;
+        this.networkManager = networkManager;
+    }
+
     public PendingConnection(MinecraftServer minecraftserver, Socket socket, String s) throws java.io.IOException { // CraftBukkit - throws IOException
         this.server = minecraftserver;
         this.networkManager = new NetworkManager(minecraftserver.getLogger(), socket, s, this, minecraftserver.H().getPrivate());
-        this.networkManager.e = 0;
+        // this.networkManager.e = 0;
     }
 
     // CraftBukkit start
@@ -146,7 +151,7 @@ public class PendingConnection extends Connection {
             String s = null;
             // CraftBukkit
             org.bukkit.event.server.ServerListPingEvent pingEvent = org.bukkit.craftbukkit.event.CraftEventFactory.callServerListPingEvent(this.server.server, getSocket().getInetAddress(), this.server.getMotd(), playerlist.getPlayerCount(), playerlist.getMaxPlayers());
-            if (packet254getinfo.d()) {
+            if (false) { // Spigot: TODO: Use trick from Bungee maybe?
                 // CraftBukkit
                 s = pingEvent.getMotd() + "\u00A7" + playerlist.getPlayerCount() + "\u00A7" + pingEvent.getMaxPlayers();
             } else {
@@ -175,9 +180,18 @@ public class PendingConnection extends Connection {
 
             this.networkManager.queue(new Packet255KickDisconnect(s));
             this.networkManager.d();
-            if (inetaddress != null && this.server.ag() instanceof DedicatedServerConnection) {
-                ((DedicatedServerConnection) this.server.ag()).a(inetaddress);
+            // Spigot start
+            if ( inetaddress != null )
+            {
+                if ( this.server.ag() instanceof DedicatedServerConnection )
+                {
+                    ((DedicatedServerConnection) this.server.ag()).a(inetaddress);
+                } else
+                {
+                    ((org.spigotmc.netty.NettyServerConnection)this.server.ag()).unThrottle( inetaddress );
+                }
             }
+            // Spigot end
 
             this.b = true;
         } catch (Exception exception) {
diff --git a/src/main/java/org/spigotmc/SpigotConfig.java b/src/main/java/org/spigotmc/SpigotConfig.java
index a0a7790..8efdca6 100644
--- a/src/main/java/org/spigotmc/SpigotConfig.java
+++ b/src/main/java/org/spigotmc/SpigotConfig.java
@@ -6,6 +6,8 @@ import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -148,4 +150,62 @@ public class SpigotConfig
         commands.put( "restart", new RestartCommand( "restart" ) );
         WatchdogThread.doStart( timeoutTime, restartOnCrash );
     }
+
+    public static class Listener
+    {
+
+        public String host;
+        public int port;
+        public boolean netty;
+        public long connectionThrottle;
+
+        public Listener(String host, int port, boolean netty, long connectionThrottle)
+        {
+            this.host = host;
+            this.port = port;
+            this.netty = netty;
+            this.connectionThrottle = connectionThrottle;
+        }
+    }
+    public static List<Listener> listeners = new ArrayList<Listener>();
+    public static int nettyThreads;
+    private static void listeners()
+    {
+        listeners.clear(); // We don't rebuild listeners on reload but we should clear them out!
+
+        Map<String, Object> def = new HashMap<String, Object>();
+        def.put( "host", "default" );
+        def.put( "port", "default" );
+        def.put( "netty", true );
+        // def.put( "throttle", "default" );
+
+        config.addDefault( "listeners", Collections.singletonList( def ) );
+        for ( Map<String, Object> info : (List<Map<String, Object>>) config.getList( "listeners" ) )
+        {
+            String host = (String) info.get( "host" );
+            if ( "default".equals( host ) )
+            {
+                host = Bukkit.getIp();
+            } else
+            {
+                throw new IllegalArgumentException( "Can only bind listener to default! Configure it in server.properties" );
+            }
+            int port ;
+            
+            if (info.get( "port" ) instanceof Integer){
+                throw new IllegalArgumentException( "Can only bind port to default! Configure it in server.properties");
+            } else{
+                port = Bukkit.getPort();
+            }
+            boolean netty = (Boolean) info.get( "netty" );
+            // long connectionThrottle = ( info.get( "throttle" ) instanceof Number ) ? ( (Number) info.get( "throttle" ) ).longValue() : Bukkit.getConnectionThrottle();
+            listeners.add( new Listener( host, port, netty, Bukkit.getConnectionThrottle() ) );
+        }
+        if ( listeners.size() != 1 )
+        {
+            throw new IllegalArgumentException( "May only have one listener!" );
+        }
+
+        nettyThreads = getInt( "settings.netty-threads", 3 );
+    }
 }
diff --git a/src/main/java/org/spigotmc/netty/CipherBase.java b/src/main/java/org/spigotmc/netty/CipherBase.java
new file mode 100644
index 0000000..c4306f7
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/CipherBase.java
@@ -0,0 +1,73 @@
+package org.spigotmc.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import javax.crypto.Cipher;
+import javax.crypto.ShortBufferException;
+
+/**
+ * Class to expose an
+ * {@link #cipher(io.netty.buffer.ByteBuf, io.netty.buffer.ByteBuf)} method to
+ * aid in the efficient passing of ByteBuffers through a cipher.
+ */
+class CipherBase
+{
+
+    private final Cipher cipher;
+    private ThreadLocal<byte[]> heapInLocal = new EmptyByteThreadLocal();
+    private ThreadLocal<byte[]> heapOutLocal = new EmptyByteThreadLocal();
+
+    private static class EmptyByteThreadLocal extends ThreadLocal<byte[]>
+    {
+
+        @Override
+        protected byte[] initialValue()
+        {
+            return new byte[ 0 ];
+        }
+    }
+
+    protected CipherBase(Cipher cipher)
+    {
+        this.cipher = cipher;
+    }
+
+    private byte[] bufToByte(ByteBuf in)
+    {
+        byte[] heapIn = heapInLocal.get();
+        int readableBytes = in.readableBytes();
+        if ( heapIn.length < readableBytes )
+        {
+            heapIn = new byte[ readableBytes ];
+            heapInLocal.set( heapIn );
+        }
+        in.readBytes( heapIn, 0, readableBytes );
+        return heapIn;
+    }
+
+    protected ByteBuf cipher(ChannelHandlerContext ctx, ByteBuf in) throws ShortBufferException
+    {
+        int readableBytes = in.readableBytes();
+        byte[] heapIn = bufToByte( in );
+
+        ByteBuf heapOut = ctx.alloc().heapBuffer( cipher.getOutputSize( readableBytes ) );
+        heapOut.writerIndex( cipher.update( heapIn, 0, readableBytes, heapOut.array(), heapOut.arrayOffset() ) );
+
+        return heapOut;
+    }
+
+    protected void cipher(ByteBuf in, ByteBuf out) throws ShortBufferException
+    {
+        int readableBytes = in.readableBytes();
+        byte[] heapIn = bufToByte( in );
+
+        byte[] heapOut = heapOutLocal.get();
+        int outputSize = cipher.getOutputSize( readableBytes );
+        if ( heapOut.length < outputSize )
+        {
+            heapOut = new byte[ outputSize ];
+            heapOutLocal.set( heapOut );
+        }
+        out.writeBytes( heapOut, 0, cipher.update( heapIn, 0, readableBytes, heapOut ) );
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/CipherDecoder.java b/src/main/java/org/spigotmc/netty/CipherDecoder.java
new file mode 100644
index 0000000..a1094d2
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/CipherDecoder.java
@@ -0,0 +1,24 @@
+package org.spigotmc.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.MessageList;
+import io.netty.handler.codec.MessageToMessageDecoder;
+import javax.crypto.Cipher;
+
+public class CipherDecoder extends MessageToMessageDecoder<ByteBuf>
+{
+
+    private final CipherBase cipher;
+
+    public CipherDecoder(Cipher cipher)
+    {
+        this.cipher = new CipherBase( cipher );
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf msg, MessageList<Object> out) throws Exception
+    {
+        out.add( cipher.cipher( ctx, msg ) );
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/CipherEncoder.java b/src/main/java/org/spigotmc/netty/CipherEncoder.java
new file mode 100644
index 0000000..2eb1dcb
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/CipherEncoder.java
@@ -0,0 +1,23 @@
+package org.spigotmc.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+import javax.crypto.Cipher;
+
+public class CipherEncoder extends MessageToByteEncoder<ByteBuf>
+{
+
+    private final CipherBase cipher;
+
+    public CipherEncoder(Cipher cipher)
+    {
+        this.cipher = new CipherBase( cipher );
+    }
+
+    @Override
+    protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws Exception
+    {
+        cipher.cipher( in, out );
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/NettyNetworkManager.java b/src/main/java/org/spigotmc/netty/NettyNetworkManager.java
new file mode 100644
index 0000000..d501d8c
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/NettyNetworkManager.java
@@ -0,0 +1,312 @@
+package org.spigotmc.netty;
+
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.MessageList;
+import io.netty.channel.socket.SocketChannel;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.security.PrivateKey;
+import java.util.AbstractList;
+import java.util.List;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import net.minecraft.server.Connection;
+import net.minecraft.server.INetworkManager;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.Packet;
+import net.minecraft.server.Packet252KeyResponse;
+import net.minecraft.server.Packet255KickDisconnect;
+import net.minecraft.server.PendingConnection;
+import net.minecraft.server.PlayerConnection;
+
+/**
+ * This class forms the basis of the Netty integration. It implements
+ * {@link INetworkManager} and handles all events and inbound messages provided
+ * by the upstream Netty process.
+ */
+public class NettyNetworkManager extends ChannelInboundHandlerAdapter implements INetworkManager
+{
+
+    private static final ExecutorService threadPool = Executors.newCachedThreadPool( new ThreadFactoryBuilder().setNameFormat( "Async Packet Handler - %1$d" ).build() );
+    private static final MinecraftServer server = MinecraftServer.getServer();
+    private static final PrivateKey key = server.H().getPrivate();
+    private static final NettyServerConnection serverConnection = (NettyServerConnection) server.ag();
+    /*========================================================================*/
+    private final Queue<Packet> syncPackets = new ConcurrentLinkedQueue<Packet>();
+    private final List<Packet> highPriorityQueue = new AbstractList<Packet>()
+    {
+        @Override
+        public void add(int index, Packet element)
+        {
+            // NOP
+        }
+
+        @Override
+        public Packet get(int index)
+        {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public int size()
+        {
+            return 0;
+        }
+    };
+    private volatile boolean connected;
+    private Channel channel;
+    private SocketAddress address;
+    Connection connection;
+    private SecretKey secret;
+    private String dcReason;
+    private Object[] dcArgs;
+    private Socket socketAdaptor;
+    private long writtenBytes;
+    private PacketWriter writer;
+
+    @Override
+    public void channelActive(ChannelHandlerContext ctx) throws Exception
+    {
+        // Channel and address groundwork first
+        channel = ctx.channel();
+        address = channel.remoteAddress();
+        // Then the socket adaptor
+        socketAdaptor = NettySocketAdaptor.adapt( (SocketChannel) channel );
+        // Followed by their first handler
+        connection = new PendingConnection( server, this );
+        writer = new PacketWriter();
+        // Finally register the connection
+        connected = true;
+        serverConnection.register( (PendingConnection) connection );
+    }
+
+    @Override
+    public void channelInactive(ChannelHandlerContext ctx) throws Exception
+    {
+        a( "disconnect.endOfStream", new Object[ 0 ] );
+    }
+
+    @Override
+    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception
+    {
+        // TODO: Remove this once we are more stable
+        // Bukkit.getServer().getLogger().severe("======================= Start Netty Debug Log =======================");
+        // Bukkit.getServer().getLogger().log(Level.SEVERE, "Error caught whilst handling " + channel, cause);
+        // Bukkit.getServer().getLogger().severe("======================= End Netty Debug Log =======================");
+        // Disconnect with generic reason + exception
+        a( "disconnect.genericReason", new Object[]
+        {
+            "Internal exception: " + cause
+        } );
+    }
+
+    @Override
+    public void messageReceived(ChannelHandlerContext ctx, MessageList<Object> msgs) throws Exception
+    {
+        MessageList<Packet> packets = msgs.cast();
+        for ( final Packet msg : packets )
+        {
+            if ( connected )
+            {
+                if ( msg instanceof Packet252KeyResponse )
+                {
+                    secret = ( (Packet252KeyResponse) msg ).a( key );
+                    Cipher decrypt = NettyServerConnection.getCipher( Cipher.DECRYPT_MODE, secret );
+                    channel.pipeline().addBefore( "decoder", "decrypt", new CipherDecoder( decrypt ) );
+                }
+
+                if ( msg.a_() )
+                {
+                    threadPool.submit( new Runnable()
+                    {
+                        public void run()
+                        {
+                            Packet packet = PacketListener.callReceived( NettyNetworkManager.this, connection, msg );
+                            if ( packet != null )
+                            {
+                                packet.handle( connection );
+                            }
+                        }
+                    } );
+                } else
+                {
+                    syncPackets.add( msg );
+                }
+            }
+        }
+    }
+
+    public Socket getSocket()
+    {
+        return socketAdaptor;
+    }
+
+    /**
+     * setHandler. Set the {@link NetHandler} used to process received packets.
+     *
+     * @param nh the new {@link NetHandler} instance
+     */
+    public void a(Connection nh)
+    {
+        connection = nh;
+    }
+
+    /**
+     * queue. Queue a packet for sending, or in this case send it to be write it
+     * straight to the channel.
+     *
+     * @param packet the packet to queue
+     */
+    public void queue(final Packet packet)
+    {
+        // Only send if channel is still connected
+        if ( connected )
+        {
+            // Process packet via handler
+            final Packet packet0 = PacketListener.callQueued( this, connection, packet );
+            highPriorityQueue.add( packet0 );
+            // If handler indicates packet send
+            if ( packet0 != null )
+            {
+                if ( channel.eventLoop().inEventLoop() )
+                {
+                    queue0( packet0 );
+                } else
+                {
+                    channel.eventLoop().execute( new Runnable()
+                    {
+                        public void run()
+                        {
+                            queue0( packet0 );
+                        }
+                    } );
+                }
+            }
+        }
+    }
+
+    private void queue0(Packet packet)
+    {
+        if ( packet instanceof Packet255KickDisconnect )
+        {
+            writer.lastFlush = 0;
+        }
+
+        writer.write( channel, this, packet );
+        if ( packet instanceof Packet252KeyResponse )
+        {
+            Cipher encrypt = NettyServerConnection.getCipher( Cipher.ENCRYPT_MODE, secret );
+            channel.pipeline().addBefore( "decoder", "encrypt", new CipherEncoder( encrypt ) );
+        }
+    }
+
+    /**
+     * wakeThreads. In Vanilla this method will interrupt the network read and
+     * write threads, thus waking them.
+     */
+    public void a()
+    {
+    }
+
+    /**
+     * processPackets. Remove up to 1000 packets from the queue and process
+     * them. This method should only be called from the main server thread.
+     */
+    public void b()
+    {
+        for ( int i = 1000; !syncPackets.isEmpty() && i >= 0; i-- )
+        {
+            if ( connection instanceof PendingConnection ? ( (PendingConnection) connection ).b : ( (PlayerConnection) connection ).disconnected )
+            {
+                syncPackets.clear();
+                break;
+            }
+
+            Packet packet = PacketListener.callReceived( this, connection, syncPackets.poll() );
+            if ( packet != null )
+            {
+                packet.handle( connection );
+            }
+        }
+
+        // Disconnect via the handler - this performs all plugin related cleanup + logging
+        if ( !connected && ( dcReason != null || dcArgs != null ) )
+        {
+            connection.a( dcReason, dcArgs );
+        }
+    }
+
+    /**
+     * getSocketAddress. Return the remote address of the connected user. It is
+     * important that this method returns a value even after disconnect.
+     *
+     * @return the remote address of this connection
+     */
+    public SocketAddress getSocketAddress()
+    {
+        return address;
+    }
+
+    public void setSocketAddress(SocketAddress address)
+    {
+        this.address = address;
+    }
+
+    /**
+     * close. Close and release all resources associated with this connection.
+     */
+    public void d()
+    {
+        if ( connected )
+        {
+            connected = false;
+            channel.close();
+        }
+    }
+
+    /**
+     * queueSize. Return the number of packets in the low priority queue. In a
+     * NIO environment this will always be 0.
+     *
+     * @return the size of the packet send queue
+     */
+    public int e()
+    {
+        return 0;
+    }
+
+    /**
+     * networkShutdown. Shuts down this connection, storing the reason and
+     * parameters, used to notify the current {@link Connection}.
+     *
+     * @param reason the main disconnect reason
+     * @param arguments additional disconnect arguments, for example, the
+     * exception which triggered the disconnect.
+     */
+    public void a(String reason, Object... arguments)
+    {
+        if ( connected )
+        {
+            dcReason = reason;
+            dcArgs = arguments;
+            d();
+        }
+    }
+
+    public long getWrittenBytes()
+    {
+        return writtenBytes;
+    }
+
+    public void addWrittenBytes(int written)
+    {
+        writtenBytes += written;
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/NettyServerConnection.java b/src/main/java/org/spigotmc/netty/NettyServerConnection.java
new file mode 100644
index 0000000..8a82352
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/NettyServerConnection.java
@@ -0,0 +1,170 @@
+package org.spigotmc.netty;
+
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelException;
+import io.netty.channel.ChannelFuture;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.ChannelOption;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.handler.timeout.ReadTimeoutHandler;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.security.GeneralSecurityException;
+import java.security.Key;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.logging.Level;
+import javax.crypto.Cipher;
+import javax.crypto.spec.IvParameterSpec;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.PendingConnection;
+import net.minecraft.server.ServerConnection;
+import org.bukkit.Bukkit;
+import org.spigotmc.SpigotConfig;
+
+/**
+ * This is the NettyServerConnection class. It implements
+ * {@link ServerConnection} and is the main interface between the Minecraft
+ * server and this NIO implementation. It handles starting, stopping and
+ * processing the Netty backend.
+ */
+public class NettyServerConnection extends ServerConnection
+{
+
+    private final ChannelFuture socket;
+    private static EventLoopGroup group;
+    private final Map<InetAddress, Long> throttle = new HashMap<InetAddress, Long>();
+    private final List<PendingConnection> pending = Collections.synchronizedList( new ArrayList<PendingConnection>() );
+
+    public void unThrottle(InetAddress address)
+    {
+        if ( address != null )
+        {
+            synchronized ( throttle )
+            {
+                throttle.remove( address );
+            }
+        }
+    }
+
+    public boolean throttle(InetAddress address)
+    {
+        long currentTime = System.currentTimeMillis();
+        synchronized ( throttle )
+        {
+            Long value = throttle.get( address );
+            if ( value != null && !address.isLoopbackAddress() && currentTime - value < d().server.getConnectionThrottle() )
+            {
+                throttle.put( address, currentTime );
+                return true;
+            }
+
+            throttle.put( address, currentTime );
+        }
+        return false;
+    }
+
+    public NettyServerConnection(final MinecraftServer ms, InetAddress host, int port)
+    {
+        super( ms );
+        if ( group == null )
+        {
+            group = new NioEventLoopGroup( SpigotConfig.nettyThreads, new ThreadFactoryBuilder().setNameFormat( "Netty IO Thread - %1$d" ).build() );
+        }
+
+        socket = new ServerBootstrap().channel( NioServerSocketChannel.class ).childHandler( new ChannelInitializer()
+        {
+            @Override
+            public void initChannel(Channel ch) throws Exception
+            {
+                // Check the throttle
+                if ( throttle( ( (InetSocketAddress) ch.remoteAddress() ).getAddress() ) )
+                {
+                    ch.close();
+                    return;
+                }
+                // Set IP_TOS
+                try
+                {
+                    ch.config().setOption( ChannelOption.IP_TOS, 0x18 );
+                } catch ( ChannelException ex )
+                {
+                    // IP_TOS is not supported (Windows XP / Windows Server 2003)
+                }
+
+                NettyNetworkManager networkManager = new NettyNetworkManager();
+                ch.pipeline()
+                        .addLast( "timer", new ReadTimeoutHandler( 30 ) )
+                        .addLast( "decoder", new PacketDecoder() )
+                        .addLast( "manager", networkManager );
+            }
+        } ).childOption( ChannelOption.TCP_NODELAY, false ).group( group ).localAddress( host, port ).bind().syncUninterruptibly();
+    }
+
+    /**
+     * Shutdown. This method is called when the server is shutting down and the
+     * server socket and all clients should be terminated with no further
+     * action.
+     */
+    @Override
+    public void a()
+    {
+        socket.channel().close().syncUninterruptibly();
+    }
+
+    @Override
+    public void b()
+    {
+        super.b(); // pulse PlayerConnections
+        for ( int i = 0; i < pending.size(); ++i )
+        {
+            PendingConnection connection = pending.get( i );
+
+            try
+            {
+                connection.d();
+            } catch ( Exception ex )
+            {
+                connection.disconnect( "Internal server error" );
+                Bukkit.getServer().getLogger().log( Level.WARNING, "Failed to handle packet: " + ex, ex );
+            }
+
+            if ( connection.b )
+            {
+                pending.remove( i-- );
+            }
+        }
+    }
+
+    public void register(PendingConnection conn)
+    {
+        pending.add( conn );
+    }
+
+    /**
+     * Return a Minecraft compatible cipher instance from the specified key.
+     *
+     * @param opMode the mode to initialize the cipher in
+     * @param key to use as the initial vector
+     * @return the initialized cipher
+     */
+    public static Cipher getCipher(int opMode, Key key)
+    {
+        try
+        {
+            Cipher cip = Cipher.getInstance( "AES/CFB8/NoPadding" );
+            cip.init( opMode, key, new IvParameterSpec( key.getEncoded() ) );
+            return cip;
+        } catch ( GeneralSecurityException ex )
+        {
+            throw new RuntimeException( ex );
+        }
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/NettySocketAdaptor.java b/src/main/java/org/spigotmc/netty/NettySocketAdaptor.java
new file mode 100644
index 0000000..5da8a59
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/NettySocketAdaptor.java
@@ -0,0 +1,294 @@
+package org.spigotmc.netty;
+
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelOption;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.InetAddress;
+import java.net.Socket;
+import java.net.SocketAddress;
+import java.net.SocketException;
+import java.nio.channels.SocketChannel;
+
+/**
+ * This class wraps a Netty {@link Channel} in a {@link Socket}. It overrides
+ * all methods in {@link Socket} to ensure that calls are not mistakingly made
+ * to the unsupported super socket. All operations that can be sanely applied to
+ * a {@link Channel} are implemented here. Those which cannot will throw an
+ * {@link UnsupportedOperationException}.
+ */
+public class NettySocketAdaptor extends Socket
+{
+
+    private final io.netty.channel.socket.SocketChannel ch;
+
+    private NettySocketAdaptor(io.netty.channel.socket.SocketChannel ch)
+    {
+        this.ch = ch;
+    }
+
+    public static NettySocketAdaptor adapt(io.netty.channel.socket.SocketChannel ch)
+    {
+        return new NettySocketAdaptor( ch );
+    }
+
+    @Override
+    public void bind(SocketAddress bindpoint) throws IOException
+    {
+        ch.bind( bindpoint ).syncUninterruptibly();
+    }
+
+    @Override
+    public synchronized void close() throws IOException
+    {
+        ch.close().syncUninterruptibly();
+    }
+
+    @Override
+    public void connect(SocketAddress endpoint) throws IOException
+    {
+        ch.connect( endpoint ).syncUninterruptibly();
+    }
+
+    @Override
+    public void connect(SocketAddress endpoint, int timeout) throws IOException
+    {
+        ch.config().setConnectTimeoutMillis( timeout );
+        ch.connect( endpoint ).syncUninterruptibly();
+    }
+
+    @Override
+    public boolean equals(Object obj)
+    {
+        return obj instanceof NettySocketAdaptor && ch.equals( ( (NettySocketAdaptor) obj ).ch );
+    }
+
+    @Override
+    public SocketChannel getChannel()
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public InetAddress getInetAddress()
+    {
+        return ch.remoteAddress().getAddress();
+    }
+
+    @Override
+    public InputStream getInputStream() throws IOException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public boolean getKeepAlive() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.SO_KEEPALIVE );
+    }
+
+    @Override
+    public InetAddress getLocalAddress()
+    {
+        return ch.localAddress().getAddress();
+    }
+
+    @Override
+    public int getLocalPort()
+    {
+        return ch.localAddress().getPort();
+    }
+
+    @Override
+    public SocketAddress getLocalSocketAddress()
+    {
+        return ch.localAddress();
+    }
+
+    @Override
+    public boolean getOOBInline() throws SocketException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public OutputStream getOutputStream() throws IOException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public int getPort()
+    {
+        return ch.remoteAddress().getPort();
+    }
+
+    @Override
+    public synchronized int getReceiveBufferSize() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.SO_RCVBUF );
+    }
+
+    @Override
+    public SocketAddress getRemoteSocketAddress()
+    {
+        return ch.remoteAddress();
+    }
+
+    @Override
+    public boolean getReuseAddress() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.SO_REUSEADDR );
+    }
+
+    @Override
+    public synchronized int getSendBufferSize() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.SO_SNDBUF );
+    }
+
+    @Override
+    public int getSoLinger() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.SO_LINGER );
+    }
+
+    @Override
+    public synchronized int getSoTimeout() throws SocketException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public boolean getTcpNoDelay() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.TCP_NODELAY );
+    }
+
+    @Override
+    public int getTrafficClass() throws SocketException
+    {
+        return ch.config().getOption( ChannelOption.IP_TOS );
+    }
+
+    @Override
+    public int hashCode()
+    {
+        return ch.hashCode();
+    }
+
+    @Override
+    public boolean isBound()
+    {
+        return ch.localAddress() != null;
+    }
+
+    @Override
+    public boolean isClosed()
+    {
+        return !ch.isOpen();
+    }
+
+    @Override
+    public boolean isConnected()
+    {
+        return ch.isActive();
+    }
+
+    @Override
+    public boolean isInputShutdown()
+    {
+        return ch.isInputShutdown();
+    }
+
+    @Override
+    public boolean isOutputShutdown()
+    {
+        return ch.isOutputShutdown();
+    }
+
+    @Override
+    public void sendUrgentData(int data) throws IOException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public void setKeepAlive(boolean on) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.SO_KEEPALIVE, on );
+    }
+
+    @Override
+    public void setOOBInline(boolean on) throws SocketException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public void setPerformancePreferences(int connectionTime, int latency, int bandwidth)
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public synchronized void setReceiveBufferSize(int size) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.SO_RCVBUF, size );
+    }
+
+    @Override
+    public void setReuseAddress(boolean on) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.SO_REUSEADDR, on );
+    }
+
+    @Override
+    public synchronized void setSendBufferSize(int size) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.SO_SNDBUF, size );
+    }
+
+    @Override
+    public void setSoLinger(boolean on, int linger) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.SO_LINGER, linger );
+    }
+
+    @Override
+    public synchronized void setSoTimeout(int timeout) throws SocketException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public void setTcpNoDelay(boolean on) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.TCP_NODELAY, on );
+    }
+
+    @Override
+    public void setTrafficClass(int tc) throws SocketException
+    {
+        ch.config().setOption( ChannelOption.IP_TOS, tc );
+    }
+
+    @Override
+    public void shutdownInput() throws IOException
+    {
+        throw new UnsupportedOperationException( "Operation not supported on Channel wrapper." );
+    }
+
+    @Override
+    public void shutdownOutput() throws IOException
+    {
+        ch.shutdownOutput().syncUninterruptibly();
+    }
+
+    @Override
+    public String toString()
+    {
+        return ch.toString();
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/PacketDecoder.java b/src/main/java/org/spigotmc/netty/PacketDecoder.java
new file mode 100644
index 0000000..f459ed1
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/PacketDecoder.java
@@ -0,0 +1,80 @@
+package org.spigotmc.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufInputStream;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.MessageList;
+import io.netty.handler.codec.ReplayingDecoder;
+import java.io.DataInput;
+import java.io.DataInputStream;
+import java.io.EOFException;
+import java.io.IOException;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.Packet;
+import net.minecraft.server.Packet254GetInfo;
+
+/**
+ * Packet decoding class backed by a reusable {@link DataInputStream} which
+ * backs the input {@link ByteBuf}. Reads an unsigned byte packet header and
+ * then decodes the packet accordingly.
+ */
+public class PacketDecoder extends ReplayingDecoder<ReadState>
+{
+
+    private DataInput input;
+    private Packet packet;
+    private boolean shutdown;
+
+    public PacketDecoder()
+    {
+        super( ReadState.HEADER );
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf in, MessageList<Object> out) throws Exception
+    {
+        if ( shutdown )
+        {
+            in.readByte(); // Discard
+            return;
+        }
+
+        if ( input == null )
+        {
+            input = new ByteBufInputStream( in );
+        }
+
+        try
+        {
+            while ( true )
+            {
+                switch ( state() )
+                {
+                    case HEADER:
+                        int packetId = input.readUnsignedByte();
+                        packet = Packet.a( MinecraftServer.getServer().getLogger(), packetId );
+                        if ( packet == null )
+                        {
+                            throw new IOException( "Bad packet id " + packetId );
+                        }
+                        checkpoint( ReadState.DATA );
+                    case DATA:
+                        packet.a( input );
+                        checkpoint( ReadState.HEADER );
+                        out.add( packet );
+                        if ( packet instanceof Packet254GetInfo )
+                        {
+                            shutdown = true;
+                            return;
+                        }
+                        packet = null;
+                        break;
+                    default:
+                        throw new IllegalStateException();
+                }
+            }
+        } catch ( EOFException ex )
+        {
+        }
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/PacketListener.java b/src/main/java/org/spigotmc/netty/PacketListener.java
new file mode 100644
index 0000000..965ba12
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/PacketListener.java
@@ -0,0 +1,112 @@
+package org.spigotmc.netty;
+
+import com.google.common.base.Preconditions;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.logging.Level;
+import net.minecraft.server.Connection;
+import net.minecraft.server.INetworkManager;
+import net.minecraft.server.Packet;
+import org.bukkit.Bukkit;
+import org.bukkit.plugin.Plugin;
+
+/**
+ * This class is used for plugins that wish to register to listen to incoming
+ * and outgoing packets. To use this class, simply create a new instance,
+ * override the methods you wish to use, and call
+ * {@link #register(org.spigotmc.netty.PacketListener, org.bukkit.plugin.Plugin)}.
+ */
+public class PacketListener
+{
+
+    /**
+     * A mapping of all registered listeners and their owning plugins.
+     */
+    private static final Map<PacketListener, Plugin> listeners = new HashMap<PacketListener, Plugin>();
+    /**
+     * A baked list of all listeners, for efficiency sake.
+     */
+    private static PacketListener[] baked = new PacketListener[ 0 ];
+
+    /**
+     * Used to register a handler for receiving notifications of packet
+     * activity.
+     *
+     * @param listener the listener to register
+     * @param plugin the plugin owning this listener
+     */
+    public static synchronized void register(PacketListener listener, Plugin plugin)
+    {
+        Preconditions.checkNotNull( listener, "listener" );
+        Preconditions.checkNotNull( plugin, "plugin" );
+        Preconditions.checkState( !listeners.containsKey( listener ), "listener already registered" );
+
+        int size = listeners.size();
+        Preconditions.checkState( baked.length == size );
+        listeners.put( listener, plugin );
+        baked = Arrays.copyOf( baked, size + 1 );
+        baked[size] = listener;
+    }
+
+    static Packet callReceived(INetworkManager networkManager, Connection connection, Packet packet)
+    {
+        for ( PacketListener listener : baked )
+        {
+            try
+            {
+                packet = listener.packetReceived( networkManager, connection, packet );
+            } catch ( Throwable t )
+            {
+                Bukkit.getServer().getLogger().log( Level.SEVERE, "Error whilst firing receive hook for packet", t );
+            }
+        }
+        return packet;
+    }
+
+    static Packet callQueued(INetworkManager networkManager, Connection connection, Packet packet)
+    {
+        for ( PacketListener listener : baked )
+        {
+            try
+            {
+                packet = listener.packetQueued( networkManager, connection, packet );
+            } catch ( Throwable t )
+            {
+                Bukkit.getServer().getLogger().log( Level.SEVERE, "Error whilst firing queued hook for packet", t );
+            }
+        }
+        return packet;
+    }
+
+    /**
+     * Called when a packet has been received and is about to be handled by the
+     * current {@link Connection}. The returned packet will be the packet passed
+     * on for handling, or in the case of null being returned, not handled at
+     * all.
+     *
+     * @param networkManager the NetworkManager receiving the packet
+     * @param connection the connection which will handle the packet
+     * @param packet the received packet
+     * @return the packet to be handled, or null to cancel
+     */
+    public Packet packetReceived(INetworkManager networkManager, Connection connection, Packet packet)
+    {
+        return packet;
+    }
+
+    /**
+     * Called when a packet is queued to be sent. The returned packet will be
+     * the packet sent. In the case of null being returned, the packet will not
+     * be sent.
+     *
+     * @param networkManager the NetworkManager which will send the packet
+     * @param connection the connection which queued the packet
+     * @param packet the queue packet
+     * @return the packet to be sent, or null if the packet will not be sent.
+     */
+    public Packet packetQueued(INetworkManager networkManager, Connection connection, Packet packet)
+    {
+        return packet;
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/PacketWriter.java b/src/main/java/org/spigotmc/netty/PacketWriter.java
new file mode 100644
index 0000000..50f59ed
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/PacketWriter.java
@@ -0,0 +1,85 @@
+package org.spigotmc.netty;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufOutputStream;
+import io.netty.channel.Channel;
+import io.netty.handler.codec.EncoderException;
+import java.io.DataOutput;
+import java.io.IOException;
+import java.util.ArrayDeque;
+import java.util.Queue;
+import net.minecraft.server.Packet;
+import net.minecraft.server.PendingConnection;
+
+/**
+ * Netty encoder which takes a packet and encodes it, and adds a byte packet id
+ * header.
+ */
+public class PacketWriter
+{
+
+    private static final int FLUSH_TIME = 1;
+    /*========================================================================*/
+    long lastFlush;
+    private final Queue<Packet> queue = new ArrayDeque<Packet>( 64 );
+
+    void write(Channel channel, NettyNetworkManager networkManager, Packet msg)
+    {
+        // Append messages to queue
+        queue.add( msg );
+
+        // If we are not in the pending connect phase, and we have not reached our timer
+        if ( !( networkManager.connection instanceof PendingConnection ) && System.currentTimeMillis() - lastFlush < FLUSH_TIME )
+        {
+            return;
+        }
+        // Update our last write time
+        lastFlush = System.currentTimeMillis();
+
+        // Since we are writing in batches it can be useful to guess the size of our output to limit memcpy
+        int estimatedSize = 0;
+        for ( Packet packet : queue )
+        {
+            estimatedSize += packet.a();
+        }
+        // Allocate an output buffer of estimated size
+        ByteBuf outBuf = channel.alloc().buffer( estimatedSize );
+        // And a stream to which we can write this buffer to
+        DataOutput dataOut = new ByteBufOutputStream( outBuf );
+        // If we aren't a success, we free the buf in the finally
+        boolean success = false;
+
+        try
+        {
+            // Iterate through all packets, this is safe as we know we will only ever get packets in the pipeline
+            for ( Packet packet : queue )
+            {
+                // Write packet ID
+                outBuf.writeByte( packet.n() );
+                // Write packet data
+                try
+                {
+                    packet.a( dataOut );
+                } catch ( IOException ex )
+                {
+                    throw new EncoderException( ex );
+                }
+            }
+            // Add to the courtesy API providing number of written bytes
+            networkManager.addWrittenBytes( outBuf.readableBytes() );
+            // Let Netty handle any errors from here on
+            success = true;
+            // Write down our single ByteBuf
+            channel.write( outBuf );
+        } finally
+        {
+            // Reset packet queue
+            queue.clear();
+            // If Netty didn't handle the freeing because we didn't get there, we must
+            if ( !success )
+            {
+                outBuf.release();
+            }
+        }
+    }
+}
diff --git a/src/main/java/org/spigotmc/netty/ReadState.java b/src/main/java/org/spigotmc/netty/ReadState.java
new file mode 100644
index 0000000..d3a9cab
--- /dev/null
+++ b/src/main/java/org/spigotmc/netty/ReadState.java
@@ -0,0 +1,17 @@
+package org.spigotmc.netty;
+
+/**
+ * Stores the state of the packet currently being read.
+ */
+public enum ReadState
+{
+
+    /**
+     * Indicates the byte representing the ID has been read.
+     */
+    HEADER,
+    /**
+     * Shows the packet body is being read.
+     */
+    DATA;
+}
-- 
1.8.1.2