Re: [Ntp] Comments after implementing draft-ietf-ntp-roughtime-05

[Christer Weinigel <[e-mail]>]

Hi,

> Hi there. I've recently implemented the draft-05 protocol in
> Roughtime (https://github.com/int08h/roughenough) with two caveats. I
> updated the server `roughtime.int08h.com:2002` to run the draft
> protocol, subject to the caveats below:

Nice.  I have set up a couple of roughtime servers using Marcus
Dansarie's implementation found at
https://github.com/dansarie/roughtimed and am trying to do some
interoperability testing with other implementations and have just taken
a quick look at your implementation.

Regarding your client implementation I see two issues when using
Dansarie's server.

The first is regarding the timestamp format:

In https://www.ietf.org/archive/id/draft-roughtime-aanchal-01.txt the
timestamp was defined as the number of microseconds since the epoch.
In the latest draft

https://www.ietf.org/archive/id/draft-ietf-ntp-roughtime-05.txt

a timestamp is defined this way: "The most significant 3 bytes contain
the integer part of a Modified Julian Date (MJD).  The least
significant 5 bytes is a count of the number of microseconds since
midnight on that day."

As far as I can tell your implementation still uses the old format so
using your client with Dansarie's server will give the wrong time.

./roughenough-client -p 1 sth1.roughtime.netnod.se 2002
Dec 08 4049 15:12:42 +00:00

Second, if I try to enable signature checking I get an error:

./roughenough-client -p 1 -v -d sth2.roughtime.netnod.se 2002 -k
"T/xxX4ERUBAOpt64Z8phWamKsASZxJ0VWuiPm3GS/8g="
Nonce is not present in the response's merkle tree',
src/bin/roughenough-client.rs:261:9

I have not dug down into this, but I guess it is due to you using the
standard SHA512/256 hash algorithm.

Marcus Dansarie has also written a Python implementation of roughtime.
 
https://github.com/dansarie/pyroughtime

His client does work with your server at roughtime.int08h.com when
using the old version of the protocol, but if I try to use the new
version it receives no response.  I have not tried to figure out why
yet, but will try to do that next week.

  /Christer