[SSHD-781] The heartbeat task of client not support keepalive function well

• Type: Question
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.4.0, 1.6.0
• Fix Version/s: 1.7.0
• Labels: test
• Environment: Any environment
• Assignee: Guillaume Nodet
• Reporter: MayDay
• Created: 26/Oct/17 08:55
• Updated: 19/Dec/19 17:37
• Resolved: 27/Oct/17 10:23

Description

The heartbeat request of sshClient is a SSH_MSG_GLOBAL_REQUEST, but the default buffer of heartbeat set false (see ClientConnectService#sendHeartbeat)

buf.putBoolean(false);

The sshServer reponse the heartbeat by the KeepAliveHandler, then AbstractConnectionService #sendGlobalResponse.

 boolean wantReply = buffer.getBoolean();

but if the buffer of heartbeat set false, then the sendGlobalResponse will not reponse sshClient because of the wantReply is false .(see AbstractConnectionService #globalRequest)

if (RequestHandler.Result.Replied.equals(result) || (!wantReply)) {
            return new AbstractIoWriteFuture(req, null) {
                {
                    setValue(Boolean.TRUE);
                }
            };
}

1 、Is it a Bug(set the heartbeat buffer false default)? how the sshClient know the server is available when the server don't response.
I have test it whth create a client with params (
HEARTBEAT_INTERAL = 60
IDLE_TIMEOUT = 300
NIO_READ_TIMEOUT = 315)and a server, and the client will close seesion after the NIO_READ_TIMEOUT.

2、If the client reach the NIO_READ_TIMEOUT, then thows a InterruptedByTimeoutException,and close the session.But the task of heratbeat not stoped, it will continue to run even though it will not send packet.See the
ClientConnectionService #startHeartBeat

service.scheduleAtFixedRate(this::sendHeartBeat, interval, interval, TimeUnit.MILLISECONDS);

if the sshClient reopen a new session and close it many times,the number of invalid scheduling heartbeat task will become very large, it's not equitable.

Issue Links

• is related to: SSHD-782 Consider implementing a "reverse" keep-alive mechanism in the server