Re: keepalive in socket server program

Alan, Nathan, Richard & Scott,
Thank you for the information.
At this time, there is only going to be one client.
I am going to use a single server job to receive the data and send it to a
data queue for processing.
At some point, the data queue method may be to slow for the volume of data
being received and I will have to look into another method.
The project that I am working on involves another software vendor, and they
are defining the interface specifications and requirements.
I will check with them as to exactly they will send as a keepalive and what
they want back.
As always, the information that I receive here in answer to my questions
has greatly improved my knowledge.

Thank you all for you help.


Jeff Young
Sr. Programmer Analyst

On Mon, Aug 31, 2015 at 12:00 AM, Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>
wrote:

It depends on what is meant by "keepalive"?

See here for a description of keepalive at the TCP layer vs higher layers:
https://en.wikipedia.org/wiki/Keepalive

If they mean keepalive at the TCP layer, that's easy enough. You can
enable that with the setsockopt() API and the TCP_KEEPALIVE option. (I
would recommend setting everything explicitly in your program rather than
relying on the CHGTCPA setting.) The rest is done for you under the
covers.

If they want keepalives at the application-level (which are, arguably,
more useful) then you need to build that into your communications protocol.
Since they're giving you specifications, I would guess that they will tell
you how the protocol (and also keep alives) work in that case.

Since you're writing a server program, please consider using INETD rather
than writing the whole thing yourself. (No need to muck about with spawn,
sendmsg, or take/givedescriptor that way...)





On 8/28/2015 3:35 PM, Jeff Young wrote:

I am working on a socket server program where the connection will remain
open most of the day. The specifications from the client (I have no
control over this) indicate that they will periodically send a keepalive
to
me.
My questions are: 1 - How do I detect that a keepalive was sent
2 - What (if anything) do I need to send back.


TIA


Jeff Young
Sr. Programmer Analyst

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