Get ClosedChannelException when close channel before SSL handshake

Hi, recently I encounter a problem when using Netty and its SlsHandler. I would like to close a channel before SSL handshake based on my throttling configuration. I try to implement as below, but I will receive ClosedChannelException when I close the channel.

I add my ThrottleHandler before SslHandler in my ChannelInitializer . It overrides the channelActive method in order to determine whether we should do the SSL handshake or close the channel before the handshake. The SslHandler is setting in a server mode.

From my understanding, the SSL handshake should starts when the channel become active, so my closing operation should run before the SSL handshakes starts. However, I still receive a ClosedChannelException when closing the channel. This exception is triggered in channelInactive method in SslHandler. Does the handshake starts when the channel is active, or it just starts when you add SslHandler to the pipeline?

Expected behavior

The channel should be closed normally without any exception. The handshake should not have started.

Actual behavior

The SslHandler triggers ClosedChannelException when I close the channel before the handshake.

java.nio.channels.ClosedChannelException
    at io.netty.handler.ssl.SslHandler.channelInactive(...)(Unknown Source) ~[netty-all-4.1.jar:4.1.6.Final]

Steps to reproduce

Normally start a simple server which enables the SSL/TLS feature by adding a SslHandler into the ChannelInitializer. The SslHandler is setup with a Java SSLEngine in server mode. Then add the ThrottleHandler (codes are listed below) before SslHandler.

Minimal yet complete reproducer code (or URL to code)

@ChannelHandler.Sharable
public class ThrottleHandler extends ChannelInboundHandlerAdapter {
    private ThrottleConfig config;
    private ThrottleConfig config;

    public ThrottleHandler(ThrottleConfig config) {
        super();
        this.config = config;
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        if (config.isThrottled) {
            log.info("Close a connection by throttle handler");
            ctx.close();
            return;
        }

        ctx.pipeline().remove(this);
        ctx.fireChannelActive();
    }
}

public class AbstractChannelInitializer extends ChannelInitializer<SocketChannel> {
    private ThrottleHandler throttleHandler;
    private SslHandler handshakeHandler;

    @Override
    protected void initChannel(SocketChannel channel) throws Exception {
        channel.pipeline().addLast(throttleHandler);
       // Add Netty SslHandler
        channel.pipeline().addLast(handshakeHandler);

        // other handlers for business logics
    }
}

Netty version

4.1.6.Final

JVM version (e.g. java -version)

java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

[normanmaurer]

@Jianzhu91 PTAL: https://github.com/netty/netty/pull/7368

[normanmaurer]

Fixed by https://github.com/netty/netty/pull/7368