SOMAXCONN, etc...

[Ed.Doxtator@xxxxxxxxx]

Phil "WebMan" Hall wrote:

>...we've found that if you're really hammering a listening process on the
AS/400,
>that the backlog parameter needs to be fairly high to avoid the AS/400
randomly
>discarding queued connections.
>The difference between AS/400 & Unix is that Unix will give you a
'Connection
>refused' if the queued connection doesn't get serviced by an accept after
a
>certain time. The AS/400 on the other hand will randomly throw out a
connection
>(not necessarily your connection) from the queue.

After speaking with IBM yesterday, it would appear that this will behaivour
will be treated as an OS/400 bug.  The blurb about the listen() function
within the _OS/400 Sockets Programming Manual V3R6_ states in Appendix A.0,
"Compatability With BSD Sockets" It seems to exist in V3R1, V3R6, and V3R7.

listen()

    On a BSD system, issuing a listen() with the backlog parameter set to a
 value
    that is less than zero or greater than {SOMAXCONN} does not result in
an error.
    In addition, the BSD implementation, in some cases, does not use the
backlog
    parameter, or uses some algorithm to come up with a final result for
the backlog
    value.  ***The OS/400 implementation returns an error if the backlog
value is not
    between zero and {SOMAXCONN}, and setting the backlog to a valid value
results in
    the value being used as the backlog.*** (emphasis added)

However, in practice, setting the backlog to a valid value does not result
in the
value being used as the backlog.  It results in the condition Phil has just
 described.

I'll let you know what happens.  IBM were surprisingly responsive yesterday
 and jumped
right in, saying up front that it was a bug.

Look after yerselves...

-Doc

P.S.  Thanks, Phil!


+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to "MIDRANGE-L@midrange.com".
| To unsubscribe from this list send email to MAJORDOMO@midrange.com
|    and specify 'unsubscribe MIDRANGE-L' in the body of your message.
| Questions should be directed to the list owner/operator: david@midrange.com
+---