Initial commit. Very broken and only does Server List Ping!

.gitignore

@@ -0,0 +1,119 @@
+
+# Created by https://www.gitignore.io/api/java,gradle,intellij
+
+### Intellij ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+### Intellij Patch ###
+# Comment Reason: https://github.com/joeblau/gitignore.io/issues/186#issuecomment-215987721
+
+# *.iml
+# modules.xml
+# .idea/misc.xml
+# *.ipr
+
+# Sonarlint plugin
+.idea/sonarlint
+
+### Java ###
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+### Gradle ###
+.gradle
+/build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+
+
+# End of https://www.gitignore.io/api/java,gradle,intellij

.idea/misc.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

build.gradle

@@ -0,0 +1,21 @@
+plugins {
+    id 'java'
+}
+
+group 'io.minimum.minecraft'
+version '1.0-SNAPSHOT'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+    maven { url 'https://jitpack.io' }
+}
+
+dependencies {
+    compile 'io.netty:netty-all:4.1.27.Final'
+    compile 'com.google.guava:guava:25.1-jre'
+    compile 'com.google.code.gson:gson:2.8.5'
+    compile 'com.github.KyoriPowered:text:v1.12-1.5.0'
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Mon Jul 23 20:52:34 EDT 2018
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip

gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'velocity'
+

src/main/java/io/minimum/minecraft/velocity/Velocity.java

@@ -0,0 +1,32 @@
+package io.minimum.minecraft.velocity;
+
+import io.minimum.minecraft.velocity.protocol.ProtocolConstants;
+import io.minimum.minecraft.velocity.protocol.netty.*;
+import io.minimum.minecraft.velocity.proxy.MinecraftClientSessionHandler;
+import io.netty.bootstrap.ServerBootstrap;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+
+public class Velocity {
+    public static void main(String... args) throws InterruptedException {
+        new ServerBootstrap()
+                .channel(NioServerSocketChannel.class)
+                .group(new NioEventLoopGroup())
+                .childHandler(new ChannelInitializer<Channel>() {
+                    @Override
+                    protected void initChannel(Channel ch) throws Exception {
+                        ch.pipeline().addLast("legacy-ping-decode", new LegacyPingDecoder());
+                        ch.pipeline().addLast("frame-decoder", new MinecraftVarintFrameDecoder());
+                        ch.pipeline().addLast("legacy-ping-encode", new LegacyPingEncoder());
+                        ch.pipeline().addLast("frame-encoder", new MinecraftVarintLengthEncoder());
+                        ch.pipeline().addLast("minecraft-decoder", new MinecraftDecoder(ProtocolConstants.Direction.TO_SERVER));
+                        ch.pipeline().addLast("minecraft-encoder", new MinecraftEncoder(ProtocolConstants.Direction.TO_CLIENT));
+                        ch.pipeline().addLast("handler", new MinecraftClientSessionHandler());
+                    }
+                })
+                .bind(26671)
+                .await();
+    }
+}

src/main/java/io/minimum/minecraft/velocity/data/ServerPing.java

@@ -0,0 +1,95 @@
+package io.minimum.minecraft.velocity.data;
+
+import net.kyori.text.Component;
+
+public class ServerPing {
+    private final Version version;
+    private final Players players;
+    private final Component description;
+    private final String favicon;
+
+    public ServerPing(Version version, Players players, Component description, String favicon) {
+        this.version = version;
+        this.players = players;
+        this.description = description;
+        this.favicon = favicon;
+    }
+
+    public Version getVersion() {
+        return version;
+    }
+
+    public Players getPlayers() {
+        return players;
+    }
+
+    public Component getDescription() {
+        return description;
+    }
+
+    public String getFavicon() {
+        return favicon;
+    }
+
+    @Override
+    public String toString() {
+        return "ServerPing{" +
+                "version=" + version +
+                ", players=" + players +
+                ", description=" + description +
+                ", favicon='" + favicon + '\'' +
+                '}';
+    }
+
+    public static class Version {
+        private final int protocol;
+        private final String version;
+
+        public Version(int protocol, String version) {
+            this.protocol = protocol;
+            this.version = version;
+        }
+
+        public int getProtocol() {
+            return protocol;
+        }
+
+        public String getVersion() {
+            return version;
+        }
+
+        @Override
+        public String toString() {
+            return "Version{" +
+                    "protocol=" + protocol +
+                    ", version='" + version + '\'' +
+                    '}';
+        }
+    }
+
+    public static class Players {
+        private final int online;
+        private final int max;
+
+        public Players(int online, int max) {
+            this.online = online;
+            this.max = max;
+        }
+
+        public int getOnline() {
+            return online;
+        }
+
+        public int getMax() {
+            return max;
+        }
+
+        @Override
+        public String toString() {
+            return "Players{" +
+                    "online=" + online +
+                    ", max=" + max +
+                    '}';
+        }
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/MinecraftPacket.java

@@ -0,0 +1,9 @@
+package io.minimum.minecraft.velocity.protocol;
+
+import io.netty.buffer.ByteBuf;
+
+public interface MinecraftPacket {
+    void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion);
+
+    void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion);
+}

src/main/java/io/minimum/minecraft/velocity/protocol/PacketWrapper.java

@@ -0,0 +1,30 @@
+package io.minimum.minecraft.velocity.protocol;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
+
+public class PacketWrapper {
+    private final MinecraftPacket packet;
+    private final ByteBuf buffer;
+
+    public PacketWrapper(MinecraftPacket packet, ByteBuf buffer) {
+        this.packet = packet;
+        this.buffer = buffer;
+    }
+
+    public MinecraftPacket getPacket() {
+        return packet;
+    }
+
+    public ByteBuf getBuffer() {
+        return buffer;
+    }
+
+    @Override
+    public String toString() {
+        return "PacketWrapper{" +
+                "packet=" + packet +
+                ", buffer=" + ByteBufUtil.hexDump(buffer) +
+                '}';
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/ProtocolConstants.java

@@ -0,0 +1,10 @@
+package io.minimum.minecraft.velocity.protocol;
+
+public enum ProtocolConstants { ;
+    public static final int MINECRAFT_1_12 = 340;
+
+    public enum Direction {
+        TO_SERVER,
+        TO_CLIENT
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/ProtocolUtils.java

@@ -0,0 +1,58 @@
+package io.minimum.minecraft.velocity.protocol;
+
+import com.google.common.base.Preconditions;
+import io.netty.buffer.ByteBuf;
+
+import java.nio.charset.StandardCharsets;
+
+public enum ProtocolUtils { ;
+    private static final int DEFAULT_MAX_STRING_SIZE = 1024 * 1024; // 1MB
+
+    public static int readVarInt(ByteBuf buf) {
+        int numRead = 0;
+        int result = 0;
+        byte read;
+        do {
+            read = buf.readByte();
+            int value = (read & 0b01111111);
+            result |= (value << (7 * numRead));
+
+            numRead++;
+            if (numRead > 5) {
+                throw new RuntimeException("VarInt is too big");
+            }
+        } while ((read & 0b10000000) != 0);
+
+        return result;
+    }
+
+    public static void writeVarInt(ByteBuf buf, int value) {
+        do {
+            byte temp = (byte)(value & 0b01111111);
+            // Note: >>> means that the sign bit is shifted with the rest of the number rather than being left alone
+            value >>>= 7;
+            if (value != 0) {
+                temp |= 0b10000000;
+            }
+            buf.writeByte(temp);
+        } while (value != 0);
+    }
+
+    public static String readString(ByteBuf buf) {
+        return readString(buf, DEFAULT_MAX_STRING_SIZE);
+    }
+
+    public static String readString(ByteBuf buf, int cap) {
+        int length = readVarInt(buf);
+        Preconditions.checkArgument(length < cap, "Bad string size (got %s, maximum is %s)", length, cap);
+        byte[] str = new byte[length];
+        buf.readBytes(str);
+        return new String(str, StandardCharsets.UTF_8);
+    }
+
+    public static void writeString(ByteBuf buf, String str) {
+        byte[] asUtf8 = str.getBytes(StandardCharsets.UTF_8);
+        writeVarInt(buf, asUtf8.length);
+        buf.writeBytes(asUtf8);
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/StateRegistry.java

@@ -0,0 +1,63 @@
+package io.minimum.minecraft.velocity.protocol;
+
+import io.minimum.minecraft.velocity.protocol.packets.Handshake;
+import io.minimum.minecraft.velocity.protocol.packets.Ping;
+import io.minimum.minecraft.velocity.protocol.packets.StatusRequest;
+import io.minimum.minecraft.velocity.protocol.packets.StatusResponse;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+public enum StateRegistry {
+    HANDSHAKE {
+        {
+            TO_SERVER.register(0x00, Handshake.class, Handshake::new);
+        }
+    },
+    STATUS {
+        {
+            TO_SERVER.register(0x00, StatusRequest.class, StatusRequest::new);
+            TO_SERVER.register(0x01, Ping.class, Ping::new);
+
+            TO_CLIENT.register(0x00, StatusResponse.class, StatusResponse::new);
+            TO_CLIENT.register(0x01, Ping.class, Ping::new);
+        }
+    };
+
+    public final ProtocolMappings TO_CLIENT = new ProtocolMappings(ProtocolConstants.Direction.TO_CLIENT, this);
+    public final ProtocolMappings TO_SERVER = new ProtocolMappings(ProtocolConstants.Direction.TO_SERVER, this);
+
+    public static class ProtocolMappings {
+        private final ProtocolConstants.Direction direction;
+        private final StateRegistry state;
+        private final Map<Integer, Supplier<? extends MinecraftPacket>> idsToSuppliers = new HashMap<>();
+        private final Map<Class<? extends MinecraftPacket>, Integer> packetClassesToIds = new HashMap<>();
+
+        public ProtocolMappings(ProtocolConstants.Direction direction, StateRegistry state) {
+            this.direction = direction;
+            this.state = state;
+        }
+
+        public void register(int id, Class<? extends MinecraftPacket> clazz, Supplier<? extends MinecraftPacket> packetSupplier) {
+            idsToSuppliers.put(id, packetSupplier);
+            packetClassesToIds.put(clazz, id);
+        }
+
+        public MinecraftPacket createPacket(int id) {
+            Supplier<? extends MinecraftPacket> supplier = idsToSuppliers.get(id);
+            if (supplier == null) {
+                return null;
+            }
+            return supplier.get();
+        }
+
+        public int getId(MinecraftPacket packet) {
+            Integer id = packetClassesToIds.get(packet.getClass());
+            if (id == null) {
+                throw new IllegalArgumentException("Supplied packet " + packet.getClass().getName() + " doesn't have a mapping. Direction " + direction + " State " + state);
+            }
+            return id;
+        }
+    }
+}

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

@@ -0,0 +1,26 @@
+package io.minimum.minecraft.velocity.protocol.netty;
+
+import io.minimum.minecraft.velocity.protocol.packets.LegacyPing;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+
+import java.util.List;
+
+public class LegacyPingDecoder extends ByteToMessageDecoder {
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
+        if (in.readableBytes() < 2) {
+            return;
+        }
+
+        short first = in.getUnsignedByte(in.readerIndex());
+        short second = in.getUnsignedByte(in.readerIndex() + 1);
+        if (first == 0xfe && second == 0x01) {
+            in.skipBytes(in.readableBytes());
+            out.add(new LegacyPing());
+        }
+
+        ctx.pipeline().remove(this);
+    }
+}

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

@@ -0,0 +1,36 @@
+package io.minimum.minecraft.velocity.protocol.netty;
+
+import com.google.common.base.Joiner;
+import com.google.common.collect.ImmutableList;
+import io.minimum.minecraft.velocity.protocol.packets.LegacyPingResponse;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+
+public class LegacyPingEncoder extends MessageToByteEncoder<LegacyPingResponse> {
+    @Override
+    protected void encode(ChannelHandlerContext ctx, LegacyPingResponse msg, ByteBuf out) throws Exception {
+        out.writeByte(0xff);
+        String serializedResponse = serialize(msg);
+        byte[] serializedBytes = serializedResponse.getBytes(StandardCharsets.UTF_16BE);
+        out.writeShort(serializedBytes.length);
+        out.writeBytes(serializedBytes);
+        System.out.println(ByteBufUtil.prettyHexDump(out));
+    }
+
+    private String serialize(LegacyPingResponse response) {
+        List<String> parts = ImmutableList.of(
+                "§1",
+                Integer.toString(response.getProtocolVersion()),
+                response.getServerVersion(),
+                response.getMotd(),
+                Integer.toString(response.getPlayersOnline()),
+                Integer.toString(response.getPlayersMax())
+        );
+        return Joiner.on('\0').join(parts);
+    }
+}

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

@@ -0,0 +1,64 @@
+package io.minimum.minecraft.velocity.protocol.netty;
+
+import com.google.common.base.Preconditions;
+import io.minimum.minecraft.velocity.protocol.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToMessageDecoder;
+
+import java.util.List;
+
+public class MinecraftDecoder extends MessageToMessageDecoder<ByteBuf> {
+    private StateRegistry state;
+    private final ProtocolConstants.Direction direction;
+    private int protocolVersion;
+
+    public MinecraftDecoder(ProtocolConstants.Direction direction) {
+        this.state = StateRegistry.HANDSHAKE;
+        this.direction = Preconditions.checkNotNull(direction, "direction");
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception {
+        if (msg.isReadable()) {
+            return;
+        }
+
+        ByteBuf slice = msg.slice().retain();
+
+        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("Decode!");
+        System.out.println("packet ID: " + packetId);
+        System.out.println("packet hexdump: " + ByteBufUtil.hexDump(slice));
+        if (packet == null) {
+            msg.skipBytes(msg.readableBytes());
+            out.add(new PacketWrapper(null, slice));
+        } else {
+            packet.decode(msg, direction, protocolVersion);
+            out.add(new PacketWrapper(packet, slice));
+        }
+    }
+
+    public int getProtocolVersion() {
+        return protocolVersion;
+    }
+
+    public void setProtocolVersion(int protocolVersion) {
+        this.protocolVersion = protocolVersion;
+    }
+
+    public StateRegistry getState() {
+        return state;
+    }
+
+    public void setState(StateRegistry state) {
+        this.state = state;
+    }
+
+    public ProtocolConstants.Direction getDirection() {
+        return direction;
+    }
+}

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

@@ -0,0 +1,46 @@
+package io.minimum.minecraft.velocity.protocol.netty;
+
+import com.google.common.base.Preconditions;
+import io.minimum.minecraft.velocity.protocol.*;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+
+public class MinecraftEncoder extends MessageToByteEncoder<MinecraftPacket> {
+    private StateRegistry state;
+    private final ProtocolConstants.Direction direction;
+    private int protocolVersion;
+
+    public MinecraftEncoder(ProtocolConstants.Direction direction) {
+        this.state = StateRegistry.HANDSHAKE;
+        this.direction = Preconditions.checkNotNull(direction, "direction");
+    }
+
+    @Override
+    protected void encode(ChannelHandlerContext ctx, MinecraftPacket msg, ByteBuf out) throws Exception {
+        StateRegistry.ProtocolMappings mappings = direction == ProtocolConstants.Direction.TO_CLIENT ? state.TO_CLIENT : state.TO_SERVER;
+        int packetId = mappings.getId(msg);
+        ProtocolUtils.writeVarInt(out, packetId);
+        msg.encode(out, direction, protocolVersion);
+    }
+
+    public int getProtocolVersion() {
+        return protocolVersion;
+    }
+
+    public void setProtocolVersion(int protocolVersion) {
+        this.protocolVersion = protocolVersion;
+    }
+
+    public StateRegistry getState() {
+        return state;
+    }
+
+    public void setState(StateRegistry state) {
+        this.state = state;
+    }
+
+    public ProtocolConstants.Direction getDirection() {
+        return direction;
+    }
+}

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

@@ -0,0 +1,28 @@
+package io.minimum.minecraft.velocity.protocol.netty;
+
+import io.minimum.minecraft.velocity.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+
+import java.util.List;
+
+public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
+        if (in.readableBytes() < 1) {
+            return;
+        }
+
+        in.markReaderIndex();
+        int packetLength = ProtocolUtils.readVarInt(in);
+        if (in.readableBytes() < packetLength) {
+            in.resetReaderIndex();
+            return;
+        }
+
+        System.out.println("Got a varint-prefixed packet length " + packetLength);
+        out.add(in.slice(in.readerIndex(), packetLength).retain());
+        in.skipBytes(packetLength);
+    }
+}

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

@@ -0,0 +1,14 @@
+package io.minimum.minecraft.velocity.protocol.netty;
+
+import io.minimum.minecraft.velocity.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.MessageToByteEncoder;
+
+public class MinecraftVarintLengthEncoder extends MessageToByteEncoder<ByteBuf> {
+    @Override
+    protected void encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) throws Exception {
+        ProtocolUtils.writeVarInt(out, msg.readableBytes());
+        out.writeBytes(msg);
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/packets/Handshake.java

@@ -0,0 +1,71 @@
+package io.minimum.minecraft.velocity.protocol.packets;
+
+import io.minimum.minecraft.velocity.protocol.MinecraftPacket;
+import io.minimum.minecraft.velocity.protocol.ProtocolConstants;
+import io.minimum.minecraft.velocity.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class Handshake implements MinecraftPacket {
+    private int protocolVersion;
+    private String serverAddress;
+    private int port;
+    private int nextStatus;
+
+    public int getProtocolVersion() {
+        return protocolVersion;
+    }
+
+    public void setProtocolVersion(int protocolVersion) {
+        this.protocolVersion = protocolVersion;
+    }
+
+    public String getServerAddress() {
+        return serverAddress;
+    }
+
+    public void setServerAddress(String serverAddress) {
+        this.serverAddress = serverAddress;
+    }
+
+    public int getPort() {
+        return port;
+    }
+
+    public void setPort(int port) {
+        this.port = port;
+    }
+
+    public int getNextStatus() {
+        return nextStatus;
+    }
+
+    public void setNextStatus(int nextStatus) {
+        this.nextStatus = nextStatus;
+    }
+
+    @Override
+    public String toString() {
+        return "Handshake{" +
+                "protocolVersion=" + protocolVersion +
+                ", serverAddress='" + serverAddress + '\'' +
+                ", port=" + port +
+                ", nextStatus=" + nextStatus +
+                '}';
+    }
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        protocolVersion = ProtocolUtils.readVarInt(buf);
+        serverAddress = ProtocolUtils.readString(buf, 255);
+        port = buf.readUnsignedShort();
+        nextStatus = ProtocolUtils.readVarInt(buf);
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        ProtocolUtils.writeVarInt(buf, protocolVersion);
+        ProtocolUtils.writeString(buf, serverAddress);
+        buf.writeShort(port);
+        ProtocolUtils.writeVarInt(buf, nextStatus);
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/packets/LegacyPing.java

@@ -0,0 +1,4 @@
+package io.minimum.minecraft.velocity.protocol.packets;
+
+public class LegacyPing {
+}

src/main/java/io/minimum/minecraft/velocity/protocol/packets/LegacyPingResponse.java

@@ -0,0 +1,82 @@
+package io.minimum.minecraft.velocity.protocol.packets;
+
+import io.minimum.minecraft.velocity.data.ServerPing;
+import net.kyori.text.serializer.ComponentSerializers;
+
+public class LegacyPingResponse {
+    private int protocolVersion;
+    private String serverVersion;
+    private String motd;
+    private int playersOnline;
+    private int playersMax;
+
+    public LegacyPingResponse() {
+    }
+
+    public LegacyPingResponse(int protocolVersion, String serverVersion, String motd, int playersOnline, int playersMax) {
+        this.protocolVersion = protocolVersion;
+        this.serverVersion = serverVersion;
+        this.motd = motd;
+        this.playersOnline = playersOnline;
+        this.playersMax = playersMax;
+    }
+
+    public int getProtocolVersion() {
+        return protocolVersion;
+    }
+
+    public void setProtocolVersion(int protocolVersion) {
+        this.protocolVersion = protocolVersion;
+    }
+
+    public String getServerVersion() {
+        return serverVersion;
+    }
+
+    public void setServerVersion(String serverVersion) {
+        this.serverVersion = serverVersion;
+    }
+
+    public String getMotd() {
+        return motd;
+    }
+
+    public void setMotd(String motd) {
+        this.motd = motd;
+    }
+
+    public int getPlayersOnline() {
+        return playersOnline;
+    }
+
+    public void setPlayersOnline(int playersOnline) {
+        this.playersOnline = playersOnline;
+    }
+
+    public int getPlayersMax() {
+        return playersMax;
+    }
+
+    public void setPlayersMax(int playersMax) {
+        this.playersMax = playersMax;
+    }
+
+    @Override
+    public String toString() {
+        return "LegacyPingResponse{" +
+                "protocolVersion=" + protocolVersion +
+                ", serverVersion='" + serverVersion + '\'' +
+                ", motd='" + motd + '\'' +
+                ", playersOnline=" + playersOnline +
+                ", playersMax=" + playersMax +
+                '}';
+    }
+
+    public static LegacyPingResponse from(ServerPing ping) {
+        return new LegacyPingResponse(ping.getVersion().getProtocol(),
+                ping.getVersion().getVersion(),
+                ComponentSerializers.LEGACY.serialize(ping.getDescription()),
+                ping.getPlayers().getOnline(),
+                ping.getPlayers().getMax());
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/packets/Ping.java

@@ -0,0 +1,34 @@
+package io.minimum.minecraft.velocity.protocol.packets;
+
+import io.minimum.minecraft.velocity.protocol.MinecraftPacket;
+import io.minimum.minecraft.velocity.protocol.ProtocolConstants;
+import io.netty.buffer.ByteBuf;
+
+public class Ping implements MinecraftPacket {
+    private long randomId;
+
+    public long getRandomId() {
+        return randomId;
+    }
+
+    public void setRandomId(long randomId) {
+        this.randomId = randomId;
+    }
+
+    @Override
+    public String toString() {
+        return "Ping{" +
+                "randomId=" + randomId +
+                '}';
+    }
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        randomId = buf.readLong();
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        buf.writeLong(randomId);
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/packets/StatusRequest.java

@@ -0,0 +1,17 @@
+package io.minimum.minecraft.velocity.protocol.packets;
+
+import io.minimum.minecraft.velocity.protocol.MinecraftPacket;
+import io.minimum.minecraft.velocity.protocol.ProtocolConstants;
+import io.netty.buffer.ByteBuf;
+
+public class StatusRequest implements MinecraftPacket {
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+
+    }
+}

src/main/java/io/minimum/minecraft/velocity/protocol/packets/StatusResponse.java

@@ -0,0 +1,35 @@
+package io.minimum.minecraft.velocity.protocol.packets;
+
+import io.minimum.minecraft.velocity.protocol.MinecraftPacket;
+import io.minimum.minecraft.velocity.protocol.ProtocolConstants;
+import io.minimum.minecraft.velocity.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class StatusResponse implements MinecraftPacket {
+    private String status;
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+    @Override
+    public String toString() {
+        return "StatusResponse{" +
+                "status='" + status + '\'' +
+                '}';
+    }
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        status = ProtocolUtils.readString(buf, Short.MAX_VALUE);
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        ProtocolUtils.writeString(buf, status);
+    }
+}

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

@@ -0,0 +1,93 @@
+package io.minimum.minecraft.velocity.proxy;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import io.minimum.minecraft.velocity.data.ServerPing;
+import io.minimum.minecraft.velocity.protocol.MinecraftPacket;
+import io.minimum.minecraft.velocity.protocol.PacketWrapper;
+import io.minimum.minecraft.velocity.protocol.StateRegistry;
+import io.minimum.minecraft.velocity.protocol.netty.MinecraftDecoder;
+import io.minimum.minecraft.velocity.protocol.netty.MinecraftEncoder;
+import io.minimum.minecraft.velocity.protocol.packets.*;
+import io.netty.channel.ChannelFutureListener;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.SimpleChannelInboundHandler;
+import net.kyori.text.Component;
+import net.kyori.text.TextComponent;
+import net.kyori.text.serializer.GsonComponentSerializer;
+
+public class MinecraftClientSessionHandler extends ChannelInboundHandlerAdapter {
+    private static final Gson GSON = new GsonBuilder()
+            .registerTypeHierarchyAdapter(Component.class, new GsonComponentSerializer())
+            .create();
+
+    @Override
+    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+        if (msg instanceof PacketWrapper) {
+            try {
+                handle(ctx, (PacketWrapper) msg);
+            } finally {
+                ((PacketWrapper) msg).getBuffer().release();
+            }
+        }
+
+        if (msg instanceof LegacyPing) {
+            System.out.println("Got LEGACY status request!");
+            ServerPing ping = new ServerPing(
+                    new ServerPing.Version(340, "1.12"),
+                    new ServerPing.Players(0, 0),
+                    TextComponent.of("this is a test"),
+                    null
+            );
+            LegacyPingResponse response = LegacyPingResponse.from(ping);
+            ctx.writeAndFlush(response);
+        }
+    }
+
+    @Override
+    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
+        cause.printStackTrace();
+        ctx.close();
+    }
+
+    private void handle(ChannelHandlerContext ctx, PacketWrapper msg) {
+        MinecraftPacket packet = msg.getPacket();
+        if (packet == null) {
+            System.out.println("no packet!");
+            return;
+        }
+
+        if (packet instanceof Handshake) {
+            System.out.println("Handshake: " + packet);
+            switch (((Handshake) packet).getNextStatus()) {
+                case 1:
+                    // status
+                    ctx.pipeline().get(MinecraftDecoder.class).setState(StateRegistry.STATUS);
+                    ctx.pipeline().get(MinecraftEncoder.class).setState(StateRegistry.STATUS);
+                    break;
+                case 2:
+                    // login
+                    throw new UnsupportedOperationException("Login not supported yet");
+            }
+        }
+
+        if (packet instanceof StatusRequest) {
+            System.out.println("Got status request!");
+            ServerPing ping = new ServerPing(
+                    new ServerPing.Version(340, "1.12.2"),
+                    new ServerPing.Players(0, 0),
+                    TextComponent.of("test"),
+                    null
+            );
+            StatusResponse response = new StatusResponse();
+            response.setStatus(GSON.toJson(ping));
+            ctx.writeAndFlush(response, ctx.voidPromise());
+        }
+
+        if (packet instanceof Ping) {
+            System.out.println("Ping: " + packet);
+            ctx.writeAndFlush(packet).addListener(ChannelFutureListener.CLOSE);
+        }
+    }
+}