Re: keepalive in socket server program

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