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- To: chrony-dev@xxxxxxxxxxxxxxxxxxxx
- Subject: [chrony-dev] Idea: Leapsecond info via DNS
- From: Rune Magnussen <rune@xxxxxxxxx>
- Date: Wed, 14 Sep 2016 23:32:55 +0200
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Hi
Poul-Henning Kamp has implemented a system to get leapsecond
information via DNS. I wonder if it is feasible to use in chronyd. The
benefit would be that there is no need to download and update
leapsecond files. On the other hand it adds a dependency on another
service. PHK has made a reference implementation in the form of a test
program here:
http://www.freebsd.dk/time/20151122.html
The DNS service is still up to date.
I found the CRC stuff somewhat confusing, but the field has a value so
when the entire packet is fed through the algorithm then the result
modulo 0x80 is zero for valid responses.
I have not looked close enough at the chronyd code to see where or how
it could be implemented, but I think chronyd should only make the DNS
lookup at startup and then perhaps once a week. At least the DNS server
should not be overloaded. With a long interval measured from startup
time I guess it is OK.
What do you think?
Kind regards Rune
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