[Pool] SNTP Client Code

Dag-Erling Smørgrav des at des.no
Wed Nov 22 12:41:42 UTC 2017

Hal Murray <hmurray at megapathdsl.net> writes:
> satyaprakash.prasad at gmail.com said:
> > Is there a Free Licence SNTP client reliable / tested code there
> > that can be made use of?
> I don't know of any code like that.

I wrote one for Tandberg Telecom (now Cisco) almost ten years ago, for
the Snoopy / Saturn generation of videoconferencing equipment.  Tandberg
allowed me to release it under a two-clause BSD license, but they
dragged their feet over it, so Harlan gave up waiting and got a student
to write the SNTP client which is now distributed with ntpd.

I just dumped the code on github:


The protocol implementation is in sntp.c, while tod.c contains code to
set the OS clock.  Note that rtcd.c (which contains main()) is missing.
I have located a copy and will add it to the repo later.

This client was written specifically to calibrate a tunable RTC for
which I had also written a Linux driver.  The RTC only had a one-second
granularity, so the driver had what was effectively a software PLL to
precisely measure the drift and adjust the calibration factor.

I don't remember if this code ever shipped with a product; I think
Tandberg ended up going for a cheaper non-tunable RTC.

Dag-Erling Smørgrav - des at des.no

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