[ntp:questions] Re: Need *very* small NTP-Server for Linux
Terje Mathisen
terje.mathisen at hda.hydro.com
Tue Sep 20 07:55:23 UTC 2005
Danny Mayer wrote:
> Johnson Luqaz wrote:
>
>> You may wish to download NetTime from
>> http://sourceforge.net/projects/nettime.
>>
>
> I doubt it. He's talking about Unix and anyway that's a SNTP client and
> not a server and he needs NTP. It's nettime is not even RFC 2030 compliant.
Writing a really tiny (S)NTP server should be a fun exercise, as long as
you can make the following (extremely) simplifying assumptions:
a) The local system clock is always correct
b) All time stamps can be assumed to be correct.
c) No need to support either authentication or any form of ntpq/ntpdc
queries.
Under these assumptions you can reduce the code to something like this:
open socket 123
while (1) {
retrieve ntp request packet
T = query system time
set T2, T3 and reference time = T
update leap pending and any other required flags
(In particular, set the stratum to a high value, like 8-10!)
return the ntp packet to the requesting client.
}
I.e. it should be possible to reduce the code to less than 1 KB as long
as the socket library code is already resident.
Terje
--
- <Terje.Mathisen at hda.hydro.com>
"almost all programming can be viewed as an exercise in caching"
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