Damion de Soto wrote:
Hi,
I was wondering if anyone knew if ntpd contained code to do this (from
RFC2030):
It is advisable to fill the non-significant low order bits of the
timestamp with a random, unbiased bitstring, both to avoid
systematic roundoff errors and as a means of loop detection and
replay detection (see below). One way of doing this is to generate
a random bitstring in a 64-bit word, then perform an arithmetic
right shift a number of bits equal to the number of significant
bits of the timestamp, then add the result to the original
timestamp.
The ntp packets from my platform all have the same fractional seconds,
so I'm guessing it does not. Is there any reason why not?
It seems a fairly trivial change in a couple of places in ntpd/ntp_proto.c
Yes and no. If your system supports either clock_gettime or getclock,
then the code does not bother with the random bitstring, since there
are only two unused bits to set. Not worth the trouble.
--
blu
Quidquid latine dictum sit, altum sonatur.
----------------------------------------------------------------------
Brian Utterback - OP/N1 RPE, Sun Microsystems, Inc.
Ph:877-259-7345, Em:brian.utterback-at-ess-you-enn-dot-kom
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