Java tutorial
/* * Quartz * Copyright (c) 2015, Minecrell <https://github.com/Minecrell> * * Based on Sponge and SpongeAPI, licensed under the MIT License (MIT). * Copyright (c) SpongePowered.org <http://www.spongepowered.org> * Copyright (c) contributors * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package net.minecrell.quartz.mixin.network; import com.google.common.base.Charsets; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import net.minecraft.server.MinecraftServer; import net.minecraft.server.network.LegacyPingHandler; import net.minecraft.server.network.NetworkSystem; import net.minecraft.server.status.ServerStatusResponse; import net.minecrell.quartz.status.QuartzLegacyMinecraftVersion; import net.minecrell.quartz.status.QuartzStatusResponse; import org.apache.logging.log4j.Logger; import org.spongepowered.asm.mixin.Mixin; import org.spongepowered.asm.mixin.Overwrite; import org.spongepowered.asm.mixin.Shadow; import java.net.InetSocketAddress; import javax.annotation.Nullable; @Mixin(LegacyPingHandler.class) public abstract class MixinLegacyPingHandler extends ChannelInboundHandlerAdapter { @Shadow private static Logger logger; @Shadow private NetworkSystem system; @Nullable private ByteBuf buf; @Shadow abstract void writeAndFlush(ChannelHandlerContext ctx, ByteBuf data); @Shadow abstract ByteBuf writeString(String string); @Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception { this.buf = ctx.alloc().buffer(); } @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { if (this.buf != null) { this.buf.release(); this.buf = null; } } @Override @Overwrite public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { ByteBuf m = (ByteBuf) msg; this.buf.writeBytes(m); m.release(); this.buf.markReaderIndex(); boolean result = false; try { result = readLegacy(ctx, this.buf); } finally { this.buf.resetReaderIndex(); if (!result) { ByteBuf buf = this.buf; this.buf = null; ctx.pipeline().remove("legacy_query"); ctx.fireChannelRead(buf); } } } private boolean readLegacy(ChannelHandlerContext ctx, ByteBuf buf) { if (buf.readUnsignedByte() != 0xFE) { return false; } MinecraftServer server = this.system.getServer(); InetSocketAddress client = (InetSocketAddress) ctx.channel().remoteAddress(); ServerStatusResponse response; int i = buf.readableBytes(); switch (i) { case 0: logger.debug("Ping: (<=1.3) from {}:{}", client.getAddress(), client.getPort()); response = QuartzStatusResponse.postLegacy(server, client, QuartzLegacyMinecraftVersion.V1_3, null); if (response != null) { this.writeResponse(ctx, String.format("%s%d%d", QuartzStatusResponse.getUnformattedMotd(response), response.getPlayers().getOnline(), response.getPlayers().getMax())); } else { ctx.close(); } break; case 1: if (buf.readUnsignedByte() != 0x01) { return false; } logger.debug("Ping: (1.4-1.5) from {}:{}", client.getAddress(), client.getPort()); response = QuartzStatusResponse.postLegacy(server, client, QuartzLegacyMinecraftVersion.V1_5, null); if (response != null) { this.writeResponse(ctx, String.format("1\u0000%d\u0000%s\u0000%s\u0000%d\u0000%d", response.getVersion().getProtocol(), response.getVersion().getName(), QuartzStatusResponse.getMotd(response), response.getPlayers().getOnline(), response.getPlayers().getMax())); } else { ctx.close(); } break; default: if (buf.readUnsignedByte() != 0x01 || buf.readUnsignedByte() != 0xFA) { return false; } if (!buf.isReadable(2)) { break; } short length = buf.readShort(); if (!buf.isReadable(length * 2)) { break; } if (!buf.readBytes(length * 2).toString(Charsets.UTF_16BE).equals("MC|PingHost")) { return false; } if (!buf.isReadable(2)) { break; } length = buf.readShort(); if (!buf.isReadable(length)) { break; } int protocol = buf.readUnsignedByte(); length = buf.readShort(); String host = buf.readBytes(length * 2).toString(Charsets.UTF_16BE); int port = buf.readInt(); logger.debug("Ping: (1.6) from {}:{}", client.getAddress(), client.getPort()); response = QuartzStatusResponse.postLegacy(server, client, new QuartzLegacyMinecraftVersion(QuartzLegacyMinecraftVersion.V1_6, protocol), InetSocketAddress.createUnresolved(host, port)); if (response != null) { this.writeResponse(ctx, String.format("1\u0000%d\u0000%s\u0000%s\u0000%d\u0000%d", response.getVersion().getProtocol(), response.getVersion().getName(), QuartzStatusResponse.getMotd(response), response.getPlayers().getOnline(), response.getPlayers().getMax())); } else { ctx.close(); } break; } return true; } private void writeResponse(ChannelHandlerContext ctx, String response) { writeAndFlush(ctx, writeString(response)); } }