Ping

src/main/java/mc/core/netty/PacketDecoder.java

@@ -7,17 +7,22 @@ package mc.core.netty;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ReplayingDecoder;
+import lombok.extern.slf4j.Slf4j;
+import mc.core.Packet;
 
 import java.util.List;
 import java.util.Optional;
+import java.util.StringJoiner;
 
 import static mc.core.netty.Utils.readVarInt;
 
+@Slf4j
 public class PacketDecoder extends ReplayingDecoder<NettyPacket> {
     @Override
     protected void decode(ChannelHandlerContext context, ByteBuf byteBuf, List<Object> list) throws Exception {
         int length = readVarInt(byteBuf);
         int id = readVarInt(byteBuf);
+        log.debug("PktLEN: {} | PktID: {}", length, id);
 
         Optional<Class<? extends NettyPacket>> packetClass = context.channel().attr(State.ATTR_STATE).get().getPacketClass(id);
 
@@ -25,9 +30,16 @@ public class PacketDecoder extends ReplayingDecoder<NettyPacket> {
             NettyPacket packet = packetClass.get().newInstance();
             packet.fillFromByteBuf(byteBuf);
             list.add(packet);
+            if (length < packet.getSize()) {
+                log.warn("WTF?! length < packet.getSize() !!");
+                log.warn("Packet size: {}", packet.getSize());
+            } else if (length > packet.getSize()) {
+                log.debug("skipBytes {}", length - packet.getSize());
+                byteBuf.skipBytes(length - packet.getSize());
+            }
         } else {
             list.add(new UnknownPacket(length, id));
-            byteBuf.skipBytes(length);
+            byteBuf.skipBytes(length-1);
         }
     }
 }

src/main/java/mc/core/netty/PacketHandler.java

@@ -7,6 +7,8 @@ package mc.core.netty;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.SimpleChannelInboundHandler;
 import lombok.extern.slf4j.Slf4j;
+import mc.core.netty.packets.HandshakeRequestPacket;
+import mc.core.netty.packets.HandshakeResponsePacket;
 
 import static mc.core.netty.Utils.equalsPacket;
 
@@ -24,6 +26,8 @@ public class PacketHandler extends SimpleChannelInboundHandler<NettyPacket> {
                 packet.toString());
 
         if (equalsPacket(packet, "HandshakeRequestPacket")) {
+            HandshakeRequestPacket pkt = (HandshakeRequestPacket) packet;
+            context.channel().attr(State.ATTR_STATE).set(pkt.getNextState());
             context.channel().writeAndFlush(new HandshakeResponsePacket());
         }
     }

src/main/java/mc/core/netty/State.java

@@ -7,13 +7,19 @@ package mc.core.netty;
 import com.google.common.collect.ImmutableMap;
 import io.netty.util.AttributeKey;
 import lombok.Getter;
+import mc.core.netty.packets.HandshakeRequestPacket;
+import mc.core.netty.packets.PingPacket;
 
 import java.util.Arrays;
 import java.util.Map;
 import java.util.Optional;
 
 public enum State {
-    Handshaking(1, ImmutableMap.of(0, HandshakeRequestPacket.class));
+    Handshaking(1, ImmutableMap.of(
+            0, HandshakeRequestPacket.class,
+            1, PingPacket.class
+    )),
+    Status(0, ImmutableMap.of(1, PingPacket.class));
 
     public static final AttributeKey<State> ATTR_STATE = AttributeKey.newInstance("ATTR_STATE");
 

src/main/java/mc/core/netty/Utils.java

@@ -32,18 +32,45 @@ public class Utils {
     }
 
     public static void writeVarInt(int value, ByteBuf byteBuf) {
+        writeVarLong(value, byteBuf);
+    }
+
+    public static int lengthVarInt(int value) {
+        return lengthVarLong(value);
+    }
+
+    public static long readVarLong(ByteBuf byteBuf) {
+        long result = 0;
+        byte read;
+        int numRead = 0;
+
+        do {
+            read = byteBuf.readByte();
+            int value = (read & 0b01111111);
+            result |= (value << (7 * numRead));
+
+            numRead++;
+            if (numRead > 10) {
+                log.warn("VarLong is too big");
+                break;
+            }
+        } while ((read & 0b10000000) != 0);
+
+        return result;
+    }
+
+    public static void writeVarLong(long value, ByteBuf byteBuf) {
         do {
             byte temp = (byte)(value & 0b01111111);
             value >>>= 7;
             if (value != 0) {
                 temp |= 0b10000000;
             }
-
             byteBuf.writeByte(temp);
         } while (value != 0);
     }
 
-    public static int lengthVarInt(int value) {
+    public static int lengthVarLong(long value) {
         int result = 0;
 
         do {
@@ -54,8 +81,19 @@ public class Utils {
         return result;
     }
 
-    public static int lengthString(String value) {
+    public static int readUnsignedShort(ByteBuf byteBuf) {
-        return lengthVarInt(value.length()) + value.length();
+        return byteBuf.readUnsignedShort();
+    }
+
+    public static int lengthUnsignedShort(int value) {
+        int result = 0;
+
+        do {
+            value >>>= 8;
+            result++;
+        } while (value != 0);
+
+        return result;
     }
 
     public static String readString(ByteBuf byteBuf) {
@@ -69,15 +107,15 @@ public class Utils {
         return new String(buffer, StandardCharsets.UTF_8);
     }
 
-    public static int readUnsignedShort(ByteBuf byteBuf) {
-        return byteBuf.readUnsignedShort();
-    }
-
     public static void writeString(String value, ByteBuf byteBuf) {
         writeVarInt(value.length(), byteBuf);
         byteBuf.writeBytes(value.getBytes());
     }
 
+    public static int lengthString(String value) {
+        return lengthVarInt(value.length()) + value.length();
+    }
+
     public static boolean equalsPacket(NettyPacket packet, String name) {
         return packet.getClass().getSimpleName().equals(name);
     }

src/main/java/mc/core/netty/packets/HandshakeRequestPacket.java

@@ -2,12 +2,15 @@
  * DmitriyMX <dimon550@gmail.com>
  * 2018-03-25
  */
-package mc.core.netty;
+package mc.core.netty.packets;
 
 import io.netty.buffer.ByteBuf;
 import lombok.Getter;
 import lombok.ToString;
 import mc.core.NotSupportException;
+import mc.core.netty.NettyPacket;
+import mc.core.netty.State;
+import mc.core.netty.UnknowState;
 
 import java.util.Optional;
 
@@ -35,11 +38,12 @@ public class HandshakeRequestPacket implements NettyPacket {
         serverPort = readUnsignedShort(byteBuf);
         final int nextStateInt = readVarInt(byteBuf);
         nextState = State.getById(nextStateInt).orElseThrow(() -> new UnknowState(nextStateInt));
+        byteBuf.skipBytes(2); //TODO magic
 
         size = lengthVarInt(id)
                 + lengthVarInt(protocolVersion)
                 + lengthString(serverAddress)
-                + lengthVarInt(serverPort)
+                + lengthUnsignedShort(serverPort)
                 + lengthVarInt(nextState.getId());
     }
 

src/main/java/mc/core/netty/packets/HandshakeResponsePacket.java

@@ -2,11 +2,12 @@
  * DmitriyMX <dimon550@gmail.com>
  * 2018-03-25
  */
-package mc.core.netty;
+package mc.core.netty.packets;
 
 import com.google.gson.JsonObject;
 import io.netty.buffer.ByteBuf;
 import mc.core.NotSupportException;
+import mc.core.netty.NettyPacket;
 
 import static mc.core.netty.Utils.*;
 

src/main/java/mc/core/netty/packets/PingPacket.java

@@ -0,0 +1,45 @@
+/*
+ * DmitriyMX <dimon550@gmail.com>
+ * 2018-03-26
+ */
+package mc.core.netty.packets;
+
+import io.netty.buffer.ByteBuf;
+import lombok.ToString;
+import mc.core.netty.NettyPacket;
+
+import static mc.core.netty.Utils.*;
+
+@ToString
+public class PingPacket implements NettyPacket {
+    private static final int id = 1;
+    private long payload;
+    private int size;
+
+    @Override
+    public void writeSelf(ByteBuf byteBuf) {
+        long payload = System.currentTimeMillis();
+        int size = lengthVarLong(payload);
+
+        writeVarInt(size, byteBuf);
+        writeVarInt(id, byteBuf);
+        writeVarLong(payload, byteBuf);
+    }
+
+    @Override
+    public void fillFromByteBuf(ByteBuf byteBuf) {
+        payload = readVarLong(byteBuf);
+        size = lengthVarInt(id)
+                + lengthVarLong(payload);
+    }
+
+    @Override
+    public int getSize() {
+        return size;
+    }
+
+    @Override
+    public int getId() {
+        return id;
+    }
+}