package com.comphenix.tinyprotocol;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import net.minecraft.util.com.mojang.authlib.GameProfile;
// These are not versioned, but they require CraftBukkit
import net.minecraft.util.io.netty.channel.Channel;
import net.minecraft.util.io.netty.channel.ChannelDuplexHandler;
import net.minecraft.util.io.netty.channel.ChannelFuture;
import net.minecraft.util.io.netty.channel.ChannelHandlerContext;
import net.minecraft.util.io.netty.channel.ChannelInboundHandlerAdapter;
import net.minecraft.util.io.netty.channel.ChannelInitializer;
import net.minecraft.util.io.netty.channel.ChannelPipeline;
import net.minecraft.util.io.netty.channel.ChannelPromise;
import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.HandlerList;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.server.PluginDisableEvent;
import org.bukkit.plugin.Plugin;
import com.comphenix.tinyprotocol.Reflection.FieldAccessor;
import com.comphenix.tinyprotocol.Reflection.MethodInvoker;
import com.google.common.collect.Lists;
import com.google.common.collect.MapMaker;
/**
* Represents a very tiny alternative to ProtocolLib in 1.7.2.
* <p>
* It now supports intercepting packets during login and status ping (such as OUT_SERVER_PING)!
* @author Kristian
*/
public abstract class TinyProtocol {
private static final AtomicInteger ID = new AtomicInteger(0);
// Used in order to lookup a channel
private static final MethodInvoker getPlayerHandle = Reflection.getMethod("{obc}.entity.CraftPlayer", "getHandle");
private static final FieldAccessor<Object> getConnection = Reflection.getField("{nms}.EntityPlayer", "playerConnection", Object.class);
private static final FieldAccessor<Object> getManager = Reflection.getField("{nms}.PlayerConnection", "networkManager", Object.class);
private static final FieldAccessor<Channel> getChannel = Reflection.getField("{nms}.NetworkManager", Channel.class, 0);
// Looking up ServerConnection
private static final Class<Object> minecraftServerClass = Reflection.getUntypedClass("{nms}.MinecraftServer");
private static final Class<Object> serverConnectionClass = Reflection.getUntypedClass("{nms}.ServerConnection");
private static final FieldAccessor<Object> getMinecraftServer = Reflection.getField("{obc}.CraftServer", minecraftServerClass, 0);
private static final FieldAccessor<Object> getServerConnection = Reflection.getField(minecraftServerClass, serverConnectionClass, 0);
private static final MethodInvoker getNetworkMarkers = Reflection.getTypedMethod(serverConnectionClass, null, List.class, serverConnectionClass);
// Packets we have to intercept
private static final Class<?> PACKET_LOGIN_IN_START = Reflection.getMinecraftClass("PacketLoginInStart");
private static final FieldAccessor<GameProfile> getGameProfile = Reflection.getField(PACKET_LOGIN_IN_START, GameProfile.class, 0);
// Speedup channel lookup
private Map<String, Channel> channelLookup = new MapMaker().weakValues().makeMap();
private Listener listener;
// Channels that have already been removed
private Set<Channel> uninjectedChannels = Collections.newSetFromMap(new MapMaker().weakKeys().<Channel, Boolean>makeMap());
// List of network markers
private List<Object> networkManagers;
// Injected channel handlers
private List<Channel> serverChannels = Lists.newArrayList();
private ChannelInboundHandlerAdapter serverChannelHandler;
private ChannelInitializer<Channel> beginInitProtocol;
private ChannelInitializer<Channel> endInitProtocol;
// Current handler name
private String handlerName;
protected volatile boolean closed;
protected Plugin plugin;
/**
* Construct a new instance of TinyProtocol, and start intercepting packets for all connected clients and future clients.
* <p>
* You can construct multiple instances per plugin.
* @param plugin - the plugin.
*/
public TinyProtocol(Plugin plugin) {
this.plugin = plugin;
// Compute handler name
this.handlerName = getHandlerName();
// Prepare existing players
registerBukkitEvents();
registerChannelHandler();
registerPlayers(plugin);
}
private void createServerChannelHandler() {
// Handle connected channels
endInitProtocol = new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel channel) throws Exception {
try {
// This can take a while, so we need to stop the main thread from interfering
synchronized (networkManagers) {
// Stop injecting channels
if (closed)
return;
injectChannelInternal(channel);
}
} catch (Exception e) {
plugin.getLogger().log(Level.SEVERE, "Cannot inject incomming channel " + channel, e);
}
}
};
// This is executed before Minecraft's channel handler
beginInitProtocol = new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel channel) throws Exception {
channel.pipeline().addLast(endInitProtocol);
}
};
serverChannelHandler = new ChannelInboundHandlerAdapter() {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
Channel channel = (Channel) msg;
// Prepare to initialize ths channel
channel.pipeline().addFirst(beginInitProtocol);
ctx.fireChannelRead(msg);
}
};
}
/**
* Register bukkit events.
*/
private void registerBukkitEvents() {
listener = new Listener() {
@EventHandler(priority = EventPriority.LOWEST)
public final void onPlayerLogin(PlayerLoginEvent e) {
if (closed)
return;
Channel channel = getChannel(e.getPlayer());
// Don't inject players that have been explicitly uninjected
if (!uninjectedChannels.contains(channel)) {
injectPlayer(e.getPlayer());
}
}
@EventHandler
public final void onPluginDisable(PluginDisableEvent e) {
if (e.getPlugin().equals(plugin)) {
close();
}
}
};
this.plugin.getServer().getPluginManager().registerEvents(listener, plugin);
}
@SuppressWarnings("unchecked")
private void registerChannelHandler() {
Object mcServer = getMinecraftServer.get(Bukkit.getServer());
Object serverConnection = getServerConnection.get(mcServer);
boolean looking = true;
// We need to synchronize against this list
networkManagers = (List<Object>) getNetworkMarkers.invoke(null, serverConnection);
createServerChannelHandler();
// Find the correct list, or implicitly throw an exception
for (int i = 0; looking; i++) {
List<Object> list = Reflection.getField(serverConnection.getClass(), List.class, i).get(serverConnection);
for (Object item : list) {
if (!ChannelFuture.class.isInstance(item))
break;
// Channel future that contains the server connection
Channel serverChannel = ((ChannelFuture)item).channel();
serverChannels.add(serverChannel);
serverChannel.pipeline().addFirst(serverChannelHandler);
looking = false;
}
}
}
private void unregisterChannelHandler() {
if (serverChannelHandler == null)
return;
for (Channel serverChannel : serverChannels) {
final ChannelPipeline pipeline = serverChannel.pipeline();
// Remove channel handler
serverChannel.eventLoop().execute(new Runnable() {
public void run() {
try {
pipeline.remove(serverChannelHandler);
} catch (NoSuchElementException e) {
// That's fine
}
}
});
}
}
private void registerPlayers(Plugin plugin) {
for (Player player : plugin.getServer().getOnlinePlayers()) {
injectPlayer(player);
}
}
/**
* Invoked when the server is starting to send a packet to a player.
* <p>
* Note that this is not executed on the main thread.
* @param reciever - the receiving player, NULL for early login/status packets.
* @param remoteAddress - remote address of the sending client. Never NULL.
* @param packet - the packet being sent.
* @return The packet to send instead, or NULL to cancel the transmission.
*/
public Object onPacketOutAsync(Player reciever, Channel channel, Object packet) {
return packet;
}
/**
* Invoked when the server has received a packet from a given player.
* <p>
* Use {@link Channel#remoteAddress()} to get the remote address of the client.
* @param sender - the player that sent the packet, NULL for early login/status packets.
* @param channel - channel that received the packet. Never NULL.
* @param packet - the packet being received.
* @return The packet to recieve instead, or NULL to cancel.
*/
public Object onPacketInAsync(Player sender, Channel channel, Object packet) {
return packet;
}
/**
* Send a packet to a particular player.
* <p>
* Note that {@link #onPacketOutAsync(Player, Object)} will be invoked with this packet.
* @param player - the destination player.
* @param packet - the packet to send.
*/
public void sendPacket(Player player, Object packet) {
sendPacket(getChannel(player), packet);
}
/**
* Send a packet to a particular client.
* <p>
* Note that {@link #onPacketOutAsync(Player, Object)} will be invoked with this packet.
* @param channel - client identified by a channel.
* @param packet - the packet to send.
*/
public void sendPacket(Channel channel, Object packet) {
channel.pipeline().writeAndFlush(packet);
}
/**
* Pretend that a given packet has been received from a player.
* <p>
* Note that {@link #onPacketInAsync(Player, Object)} will be invoked with this packet.
* @param player - the player that sent the packet.
* @param packet - the packet that will be received by the server.
*/
public void receivePacket(Player player, Object packet) {
receivePacket(getChannel(player), packet);
}
/**
* Pretend that a given packet has been received from a given client.
* <p>
* Note that {@link #onPacketInAsync(Player, Object)} will be invoked with this packet.
* @param channel - client identified by a channel.
* @param packet - the packet that will be received by the server.
*/
public void receivePacket(Channel channel, Object packet) {
channel.pipeline().context("encoder").fireChannelRead(packet);
}
/**
* Retrieve the name of the channel injector, default implementation is "tiny-" + plugin name + "-" + a unique ID.
* <p>
* Note that this method will only be invoked once. It is no longer necessary to override this to support multiple instances.
* @return A unique channel handler name.
*/
protected String getHandlerName() {
return "tiny-" + plugin.getName() + "-" + ID.incrementAndGet();
}
/**
* Add a custom channel handler to the given player's channel pipeline,
* allowing us to intercept sent and received packets.
* <p>
* This will automatically be called when a player has logged in.
* @param player - the player to inject.
*/
public void injectPlayer(Player player) {
injectChannelInternal(getChannel(player)).player = player;
}
/**
* Add a custom channel handler to the given channel.
* @param player - the channel to inject.
* @return The intercepted channel, or NULL if it has already been injected.
*/
public void injectChannel(Channel channel) {
injectChannelInternal(channel);
}
/**
* Add a custom channel handler to the given channel.
* @param player - the channel to inject.
* @return The packet interceptor.
*/
private PacketInterceptor injectChannelInternal(Channel channel) {
try {
PacketInterceptor interceptor = (PacketInterceptor) channel.pipeline().get(handlerName);
// Inject our packet interceptor
if (interceptor == null) {
interceptor = new PacketInterceptor();
channel.pipeline().addBefore("packet_handler", handlerName, interceptor);
uninjectedChannels.remove(channel);
}
return interceptor;
} catch (IllegalArgumentException e) {
// Try again
return (PacketInterceptor) channel.pipeline().get(handlerName);
}
}
/**
* Retrieve the Netty channel associated with a player. This is cached.
* @param player - the player.
* @return The Netty channel.
*/
public Channel getChannel(Player player) {
Channel channel = channelLookup.get(player.getName());
// Lookup channel again
if (channel == null) {
Object connection = getConnection.get(getPlayerHandle.invoke(player));
Object manager = getManager.get(connection);
channelLookup.put(player.getName(), channel = getChannel.get(manager));
}
return channel;
}
/**
* Uninject a specific player.
* @param player - the injected player.
*/
public void uninjectPlayer(Player player) {
uninjectChannel(getChannel(player));
}
/**
* Uninject a specific channel.
* <p>
* This will also disable the automatic channel injection that occurs when a player has properly logged in.
* @param channel - the injected channel.
*/
public void uninjectChannel(final Channel channel) {
// No need to guard against this if we're closing
if (!closed) {
uninjectedChannels.add(channel);
}
// See ChannelInjector in ProtocolLib, line 590
channel.eventLoop().execute(new Runnable() {
@Override
public void run() {
channel.pipeline().remove(handlerName);
}
});
}
/**
* Determine if the given player has been injected by TinyProtocol.
* @param player - the player.
* @return TRUE if it is, FALSE otherwise.
*/
public boolean hasInjected(Player player) {
return hasInjected(getChannel(player));
}
/**
* Determine if the given channel has been injected by TinyProtocol.
* @param channel - the channel.
* @return TRUE if it is, FALSE otherwise.
*/
public boolean hasInjected(Channel channel) {
return channel.pipeline().get(handlerName) != null;
}
/**
* Cease listening for packets. This is called automatically when your plugin is disabled.
*/
public final void close() {
if (!closed) {
closed = true;
// Remove our handlers
for (Player player : plugin.getServer().getOnlinePlayers()) {
uninjectPlayer(player);
}
// Clean up Bukkit
HandlerList.unregisterAll(listener);
unregisterChannelHandler();
}
}
/**
* Channel handler that is inserted into the player's channel pipeline, allowing us to intercept sent and received packets.
* @author Kristian
*/
private final class PacketInterceptor extends ChannelDuplexHandler {
// Updated by the login event
public volatile Player player;
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
// Intercept channel
final Channel channel = ctx.channel();
handleLoginStart(channel, msg);
try {
msg = onPacketInAsync(player, channel, msg);
} catch (Exception e) {
plugin.getLogger().log(Level.SEVERE, "Error in onPacketInAsync().", e);
}
if (msg != null) {
super.channelRead(ctx, msg);
}
}
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
try {
msg = onPacketOutAsync(player, ctx.channel(), msg);
} catch (Exception e) {
plugin.getLogger().log(Level.SEVERE, "Error in onPacketOutAsync().", e);
}
if (msg != null) {
super.write(ctx, msg, promise);
}
}
private void handleLoginStart(Channel channel, Object packet) {
if (PACKET_LOGIN_IN_START.isInstance(packet)) {
GameProfile profile = getGameProfile.get(packet);
channelLookup.put(profile.getName(), channel);
}
}
}
}