[jboss-jira] [JBoss JIRA] Commented: (JBREM-991) Investigate MulticastDetector message flood

[Ron Sigal (JIRA)]

    [ https://jira.jboss.org/jira/browse/JBREM-991?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12423581#action_12423581 ] 

Ron Sigal commented on JBREM-991:
---------------------------------

It seems that the problem is a combination of 

 1) the fact that listen() calls heartbeat() upon receiving something other than a Detection, and

 2) the fact that when heartbeat() creates a null Detection (due to the fact that there are no servers running in the JVM), it sends an empty packet.

So heartbeat() sends a null Detection, listen() receives it and calls heartbeat(), which sends out a Detection, etc.  The problem is that, even though the timing of heartbeat() running in the Heartbeat TimerTask is regulated, listen() is not - it responds immediately upon reading something from the multicast socket, and the response can include a call to heartbeat.  

MulticastDetector.heartbeat() has been changed so that if it creates a null Detection, it just returns instead of sending it.

There are no particular unit tests.  Will watch hudson for multicast detection related failures.

> Investigate MulticastDetector message flood
> -------------------------------------------
>
>                 Key: JBREM-991
>                 URL: https://jira.jboss.org/jira/browse/JBREM-991
>             Project: JBoss Remoting
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>            Reporter: Ron Sigal
>            Assignee: Ron Sigal
>             Fix For: 2.4.0.SP1
>
>
> A use has reported that org.jboss.remoting.detection.multicast.MulticastDetector is flooding the network with messages.  The problem might lie MulticastDetector.listen():
>             else
>             {
>                // for now, assume anything *not* of type Detection
>                // is a prompt to send out detection msg
>                heartbeat();
>             }

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