feat(network): add isolated packet codec and stream layer

src/main/java/cn/rukkit/network/core/packet/Packet.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2020-2022 RukkitDev Team and contributors.
+ *
+ * This project uses GNU Affero General Public License v3.0.You can find this license in the following link.
+ * 本项目使用 GNU Affero General Public License v3.0 许可证，你可以在下方链接查看:
+ *
+ * https://github.com/RukkitDev/Rukkit/blob/master/LICENSE
+ */
+
+package cn.rukkit.network.core.packet;
+
+/**
+ * A length-prefixed game packet payload and its protocol type.
+ *
+ * <p>The wire format is a four-byte payload length, followed by a four-byte
+ * packet type and the payload bytes. The class intentionally keeps the fields
+ * mutable because packet builders in the existing network stack fill the
+ * payload after constructing the packet.</p>
+ */
+public class Packet {
+    /** Sentinel used when the framed protocol should not impose a payload limit. */
+    public static final int NO_MAX_FRAME_LENGTH = Integer.MAX_VALUE;
+
+    /** The first migration stage deliberately leaves the payload size unlimited. */
+    public static final int DEFAULT_MAX_FRAME_LENGTH = NO_MAX_FRAME_LENGTH;
+
+    public byte[] bytes;
+    public int type;
+
+    public Packet(int type) {
+        this.type = type;
+    }
+
+    public Packet(int type, byte[] bytes) {
+        this.type = type;
+        this.bytes = bytes;
+    }
+
+    public Packet() {
+        this(0);
+    }
+}

src/main/java/cn/rukkit/network/core/packet/PacketDecoder.java

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+/*
+ * Copyright 2020-2022 RukkitDev Team and contributors.
+ *
+ * This project uses GNU Affero General Public License v3.0.You can find this license in the following link.
+ * 本项目使用 GNU Affero General Public License v3.0 许可证，你可以在下方链接查看:
+ *
+ * https://github.com/RukkitDev/Rukkit/blob/master/LICENSE
+ */
+
+package cn.rukkit.network.core.packet;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.ByteToMessageDecoder;
+import io.netty.handler.codec.CorruptedFrameException;
+import io.netty.handler.codec.TooLongFrameException;
+import java.util.List;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/** Decodes the length-prefixed packet wire format. */
+public class PacketDecoder extends ByteToMessageDecoder {
+    private static final int HEADER_SIZE = Integer.BYTES * 2;
+    private static final Logger LOG = LoggerFactory.getLogger(PacketDecoder.class);
+
+    private final int maxFrameLength;
+
+    public PacketDecoder() {
+        this(Packet.DEFAULT_MAX_FRAME_LENGTH);
+    }
+
+    public PacketDecoder(int maxFrameLength) {
+        if (maxFrameLength <= 0) {
+            throw new IllegalArgumentException("maxFrameLength must be positive");
+        }
+        this.maxFrameLength = maxFrameLength;
+    }
+
+    public int getMaxFrameLength() {
+        return maxFrameLength;
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext context, ByteBuf in, List<Object> out) {
+        if (in.readableBytes() < HEADER_SIZE) {
+            return;
+        }
+
+        in.markReaderIndex();
+        int length = in.readInt();
+        int type = in.readInt();
+
+        if (length < 0) {
+            throw new CorruptedFrameException("negative packet payload length: " + length);
+        }
+        if (length > maxFrameLength) {
+            throw new TooLongFrameException(
+                    "packet payload length " + length + " exceeds " + maxFrameLength);
+        }
+        if (in.readableBytes() < length) {
+            in.resetReaderIndex();
+            return;
+        }
+
+        byte[] bytes = new byte[length];
+        in.readBytes(bytes);
+
+        Packet packet = new Packet(type, bytes);
+        if (LOG.isTraceEnabled() && (type != PacketType.TICK || length > 20)) {
+            LOG.trace("Received packet type={} size={}", type, length);
+        }
+        out.add(packet);
+    }
+}

src/main/java/cn/rukkit/network/core/packet/PacketEncoder.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2020-2022 RukkitDev Team and contributors.
+ *
+ * This project uses GNU Affero General Public License v3.0.You can find this license in the following link.
+ * 本项目使用 GNU Affero General Public License v3.0 许可证，你可以在下方链接查看:
+ *
+ * https://github.com/RukkitDev/Rukkit/blob/master/LICENSE
+ */
+
+package cn.rukkit.network.core.packet;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.handler.codec.EncoderException;
+import io.netty.handler.codec.MessageToByteEncoder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/** Encodes a {@link Packet} as length, type and payload. */
+public class PacketEncoder extends MessageToByteEncoder<Packet> {
+    private static final Logger LOG = LoggerFactory.getLogger(PacketEncoder.class);
+
+    private final int maxFrameLength;
+
+    public PacketEncoder() {
+        this(Packet.DEFAULT_MAX_FRAME_LENGTH);
+    }
+
+    public PacketEncoder(int maxFrameLength) {
+        if (maxFrameLength <= 0) {
+            throw new IllegalArgumentException("maxFrameLength must be positive");
+        }
+        this.maxFrameLength = maxFrameLength;
+    }
+
+    public int getMaxFrameLength() {
+        return maxFrameLength;
+    }
+
+    @Override
+    protected void encode(ChannelHandlerContext context, Packet packet, ByteBuf out) {
+        if (packet == null) {
+            throw new EncoderException("packet must not be null");
+        }
+        if (packet.bytes == null) {
+            throw new EncoderException("packet payload must not be null");
+        }
+        if (packet.bytes.length > maxFrameLength) {
+            throw new EncoderException("packet payload exceeds maxFrameLength: " + packet.bytes.length);
+        }
+
+        if (LOG.isTraceEnabled() && (packet.type != PacketType.TICK || packet.bytes.length > 20)) {
+            LOG.trace("Sending packet type={} size={}", packet.type, packet.bytes.length);
+        }
+
+        out.writeInt(packet.bytes.length);
+        out.writeInt(packet.type);
+        out.writeBytes(packet.bytes);
+    }
+}

src/main/java/cn/rukkit/network/core/packet/PacketType.java

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+package cn.rukkit.network.core.packet;
+
+/** Packet type identifiers used by the game protocol. */
+public final class PacketType {
+    private PacketType() {
+    }
+
+    // Server commands
+    public static final int REGISTER_CONNECTION = 161;
+    public static final int TEAM_LIST = 115;
+    public static final int HEART_BEAT = 108;
+    public static final int SEND_CHAT = 141;
+    public static final int SERVER_INFO = 106;
+    public static final int START_GAME = 120;
+    public static final int QUESTION = 117;
+    public static final int QUESTION_RESPONCE = 118;
+    public static final int QUESTION_RESPONSE = QUESTION_RESPONCE;
+    public static final int KICK = 150;
+    public static final int RETURN_TO_BATTLEROOM = 122;
+
+    // Client commands
+    public static final int PREREGISTER_CONNECTION = 160;
+    public static final int HEART_BEAT_RESPONSE = 109;
+    public static final int ADD_CHAT = 140;
+    public static final int PLAYER_INFO = 110;
+    public static final int DISCONNECT = 111;
+    public static final int READY = 112;
+
+    // Game commands
+    public static final int ADD_GAMECOMMAND = 20;
+    public static final int TICK = 10;
+    public static final int SYNC_CHECKSUM = 30;
+    public static final int SYNC_CHECKSUM_RESPONCE = 31;
+    public static final int SYNC_CHECKSUM_RESPONSE = SYNC_CHECKSUM_RESPONCE;
+    public static final int SYNC = 35;
+
+    // Relay commands
+    public static final int RELAY_117 = 117;
+    public static final int RELAY_118_117_RETURN = 118;
+    public static final int RELAY_POW = 151;
+    public static final int RELAY_POW_RECEIVE = 152;
+    public static final int RELAY_VERSION_INFO = 163;
+    public static final int RELAY_BECOME_SERVER = 170;
+    public static final int FORWARD_CLIENT_ADD = 172;
+    public static final int FORWARD_CLIENT_REMOVE = 173;
+    public static final int PACKET_FORWARD_CLIENT_FROM = 174;
+    public static final int PACKET_FORWARD_CLIENT_TO = 175;
+    public static final int PACKET_FORWARD_CLIENT_TO_REPEATED = 176;
+    public static final int PACKET_RECONNECT_TO = 178;
+}