Netty 4.0.0.CR3 - LengthFieldBasedFrameDecoder maxFrameLength 超过 Integer.MAX_VALUE

Question

到目前为止，我一直在考虑从 Netty 版本 3.5.7.Final 升级到 4.0.0CR3，直到在升级过程中遇到最后一个问题……LengthFieldBasedFrameDecoder。每个可用的构造函数都需要一个 maxFrameLength，我将其设置为 Integer.MAX_VALUE，但是在运行客户端/服务器时，我得到几个堆栈跟踪（如下所示），表明已超过 Integer.MAX_VALUE (2147483647)。我试图通过挖掘 API 文档和其他各种 stackoverflow 帖子中的 ChannelConfig 类来配置最大通道缓冲区大小，但仍然没有成功。有谁知道我是否可以设置缺少的选项或防止读取量如此之高的方法？

堆栈跟踪：

io.netty.handler.codec.TooLongFrameException: Adjusted frame length exceeds 2147483647: 4156555235 - discarded
at io.netty.handler.codec.LengthFieldBasedFrameDecoder.fail(LengthFieldBasedFrameDecoder.java:486)
at io.netty.handler.codec.LengthFieldBasedFrameDecoder.failIfNecessary(LengthFieldBasedFrameDecoder.java:462)
at io.netty.handler.codec.LengthFieldBasedFrameDecoder.decode(LengthFieldBasedFrameDecoder.java:397)
at io.netty.handler.codec.LengthFieldBasedFrameDecoder.decode(LengthFieldBasedFrameDecoder.java:352)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:111)
at io.netty.handler.codec.ByteToMessageDecoder.inboundBufferUpdated(ByteToMessageDecoder.java:69)
at io.netty.channel.ChannelInboundByteHandlerAdapter.inboundBufferUpdated(ChannelInboundByteHandlerAdapter.java:46)
at io.netty.channel.DefaultChannelHandlerContext.invokeInboundBufferUpdated(DefaultChannelHandlerContext.java:1031)
at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated0(DefaultChannelHandlerContext.java:998)
at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated(DefaultChannelHandlerContext.java:978)
at io.netty.handler.timeout.IdleStateHandler.inboundBufferUpdated(IdleStateHandler.java:257)
at io.netty.channel.DefaultChannelHandlerContext.invokeInboundBufferUpdated(DefaultChannelHandlerContext.java:1057)
at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated0(DefaultChannelHandlerContext.java:998)
at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated(DefaultChannelHandlerContext.java:978)
at io.netty.channel.DefaultChannelPipeline.fireInboundBufferUpdated(DefaultChannelPipeline.java:828)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:118)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:429)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:392)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:322)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:114)
at java.lang.Thread.run(Thread.java:680)

我的客户端配置如下：

peerClient.bootstrap = new Bootstrap();

peerClient.bootstrap.group(new NioEventLoopGroup())
          .channel(NioSocketChannel.class)
          .option(ChannelOption.ALLOCATOR, UnpooledByteBufAllocator.DEFAULT)
          .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 120000)
          .option(ChannelOption.SO_KEEPALIVE, true)
          .option(ChannelOption.TCP_NODELAY, true)
          .option(ChannelOption.SO_REUSEADDR, true)
          .handler(PeerInitializer.newInstance());

我的服务器配置：

result.serverBootstrap = new ServerBootstrap();

result.serverBootstrap.group(new NioEventLoopGroup(), new NioEventLoopGroup())
      .channel(NioServerSocketChannel.class)
      .handler(new LoggingHandler(LogLevel.INFO))
      .childHandler(PeerInitializer.newInstance())
      .childOption(ChannelOption.ALLOCATOR, UnpooledByteBufAllocator.DEFAULT);

使用扩展 ChannelInitializer 的自定义类覆盖的 initChannel 方法

public class PeerInitializer extends ChannelInitializer<SocketChannel>

@Override
protected void initChannel(SocketChannel ch) throws Exception {
    final ChannelPipeline pipeline = ch.pipeline();

    pipeline.addLast(
            messageEncoder,
            HandshakeDecoder.newInstance(),
            connectionHandler,
            handshakeHandler,
            new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4),
            messageHandler);
}

Answer 1

在netty中，将4字节长度字段转换为无符号整数（实际上是长）

LengthFieldBasedFrameDecoder.java

private long getFrameLength(ByteBuf in, int actualLengthFieldOffset) {
    in = in.order(byteOrder);
    long frameLength;
    switch (lengthFieldLength) {
    case 1:
        frameLength = in.getUnsignedByte(actualLengthFieldOffset);
        break;
    case 2:
        frameLength = in.getUnsignedShort(actualLengthFieldOffset);
        break;
    case 3:
        frameLength = in.getUnsignedMedium(actualLengthFieldOffset);
        break;
    // This Code
    case 4:
        frameLength = in.getUnsignedInt(actualLengthFieldOffset);
        break;
    case 8:
        frameLength = in.getLong(actualLengthFieldOffset);
        break;
    default:
        throw new Error("should not reach here");
    }
    return frameLength;
}

AbstractByteBuf.java

@Override
public long getUnsignedInt(int index) {
    return getInt(index) & 0xFFFFFFFFL;
}

4156555235 是 -138412061。

代码：

int i = 0xF7BFFFE3;
System.out.println(i);

检查长度字段的值。

试试这个：

你的 ChannelInitializer

public class PeerInitializer extends ChannelInitializer<SocketChannel>

@Override
protected void initChannel(SocketChannel ch) throws Exception {
    final ChannelPipeline pipeline = ch.pipeline();

    pipeline.addLast(
            new ByteLoggingHandler(LogLevel.INFO), // add
            messageEncoder,
            HandshakeDecoder.newInstance(),
            connectionHandler,
            handshakeHandler,
            new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4),
            messageHandler);
}

希望这会有所帮助。