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Posted to dev@mina.apache.org by "Goldstein Lyor (JIRA)" <ji...@apache.org> on 2017/10/26 16:24:00 UTC
[jira] [Commented] (SSHD-781) The heartbeat task of client not
support keepalive function well
[ https://issues.apache.org/jira/browse/SSHD-781?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16220719#comment-16220719 ]
Goldstein Lyor commented on SSHD-781:
-------------------------------------
Send a keep-alive message with _wantReply=true_ may cause {{SSH_MSG_FAILURE}}-s to be sent since the peer does not "understand" these messages.
> The heartbeat task of client not support keepalive function well
> ----------------------------------------------------------------
>
> Key: SSHD-781
> URL: https://issues.apache.org/jira/browse/SSHD-781
> Project: MINA SSHD
> Issue Type: Question
> Affects Versions: 1.4.0, 1.6.0
> Environment: Any environment
> Reporter: MayDay
> Assignee: Goldstein Lyor
> Labels: test
>
>
> The heartbeat request of sshClient is a SSH_MSG_GLOBAL_REQUEST, but the default buffer of heartbeat set false (see [ClientConnectService#sendHeartbeat|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/client/session/ClientConnectionService.java])
> {code:java}
> buf.putBoolean(false);
> {code}
> The sshServer reponse the heartbeat by the [KeepAliveHandler|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/server/global/KeepAliveHandler.java], then [AbstractConnectionService #sendGlobalResponse|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractConnectionService.java].
> {code:java}
> boolean wantReply = buffer.getBoolean();
> {code}
> but if the buffer of heartbeat set false, then the sendGlobalResponse will not reponse sshClient {color:#205081}because of the wantReply is false{color} .(see [AbstractConnectionService #globalRequest|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractConnectionService.java])
> {code:java}
> if (RequestHandler.Result.Replied.equals(result) || (!wantReply)) {
> return new AbstractIoWriteFuture(req, null) {
> {
> setValue(Boolean.TRUE);
> }
> };
> }
> {code}
> 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 {color:#8eb021}InterruptedByTimeoutException{color},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|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/client/session/ClientConnectionService.java]
> {code:java}
> service.scheduleAtFixedRate(this::sendHeartBeat, interval, interval, TimeUnit.MILLISECONDS);
> {code}
> 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.
>
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