Joe,
That's a typo; event 16 does not exist. Glad you caught that.
Dave
Joseph Gwinn wrote:
Dave,
In article <4ba2c1ff.3060...@udel.edu>, David Mills <mi...@udel.edu> wrote:
Joe,
You and Dave are working way too hard. The bits and pieces are
documented on the ntpq page and on the Event Messages and Status Codes page.
This would be <http://www.eecis.udel.edu/~mills/ntp/html/decode.html#peer>,
which I didn't know about, but is exactly what I seek. And it wasn't a secret
after all.
But I have a question, a homework example, and a suggestion.
First the question: The Code field of the Peer Status Word is 4 bits wide, and
yet codes are defined for values from 1 to 10 hex (decimal 16), which doesn't
quite map. How does the code value fit into the field? Wraparound, so 10 (TAI)
becomes zero?
The homework example: The PSW word that started this exercise is "963a". If I
understand, this word decodes as follows:
Status field - host_reachable plus persistent_association
Select field - system_peer (gets the star)
Count field - 3
Code field - become system peer (assuming code values are truncated to 4 bits,
so hex 10 becomes 0)
And 9614 decodes to host_reachable plus persistent_association, system_peer
(gets the star), count=1, and server_reachable.
And the suggestion: I was misled by some of the NTPv4 documentation,
specifically the NTPv4 peerstats file documentation in
<http://www.eecis.udel.edu/~mills/ntp/html/monopt.html>.
The note under the table defining peerstats record fields reads "The status
field is encoded in hex format as described in Appendix B of the NTP
specification RFC 1305". This is no longer really true, as you discuss below.
In particular, codes exceeding 5 are not defined in 1305, and some of the
definitions appear to have changed (or at least have been clarified) so it would
be helpful to add a pointer to
<http://www.eecis.udel.edu/~mills/ntp/html/decode.html#peer> to monopt.html.
RFC-1305 was written in 1992. It's been 18 years since then, so you
should expect changes from time to time. Changes are not done lightly;
they reflect updates in the algorithms and interpretation of the
statistics and state variables. If the interpretation has not changed,
the name and code have not changed. If it has been changed or has become
obsolete, the name is not reused.
This is good. There is far too much existing base to do it any other way.
Thanks,
Joe Gwinn
Dave
Joseph Gwinn wrote:
In article
<46f5ae0a-93d6-44ea-812f-e4da2ae2c...@a16g2000pre.googlegroups.com>,
Dave Hart <daveh...@gmail.com> wrote:
There were backward-incompatible changes on May 13, 2008 for ntp-dev
4.2.5p114:
<http://ntp.bkbits.net:8080/ntp-dev/?PAGE=cset&REV=48295cccnu3e5cmGhOzAS7hA-
pVG3A>
Once again statestr.c is your friend:
<http://ntp.bkbits.net:8080/ntp-dev/libntp/statestr.c?PAGE=diffs&REV=4829513
7L4-SOuAy6YZauDbZtW6DRg>
If you want to be able to decode these bits for ntpd versions from
before and after the change correctly, you need to query the version
string of ntpd, sadly, such as with:
ntpq -c "rv 0 version"
So that's how you get the NTP version (rather than the ntpq version)!
When our sysadmins first installed NTPv4, they used the version command of
ntpq,
which said "4". Check!
I came by a few days later to look at the purported NTPv4 loopstats and
peerstats files, and (ever suspicious) checked to see what version of NTP
had in
fact generated them. Still NTPv3. The sysadmins had been snookered by
ntpq,
which failed to make unambiguous whose version it was reporting upon.
This had also happened to me back in the days of NTPv3, but I was saved
because
I knew that "4" could not be the answer. But I never did figure out how to
get
ntpq to tell me the version of the ntp daemon.
and then parse for 4.2.5p114 or later. The format for the version
string can include an optional -RC# suffix, and before long, there may
be releases with a -beta# suffix in the -stable branch, such as
4.2.6p2-beta1 as a prelude to 4.2.6p2-RC1.
Still evolving, rapidly. OK. I will have to find out exactly which version
I
have. I have no need to decode status from prior versions. I need only to
understand the status codes from what I am running, to understand what is
and is
not working in my system. Fixes have included giving NTP and related
traffic
its own dedicated LAN and LAN ports on the hosts, to reduce buffeting of NTP
packets and/or the daemon by unrelated but heavy packet traffic. The
buffeting
causes what appear to be large, random, and often asymmetric transport
delays.
Is there available a written discussion of which changes were made and why?
This could be worth reading.
More generally, these backward-incompatible changes will cause great
confusion
and difficulty in transitioning to NTPv4 unless ntpq is kept up to date, and
the
descriptions of what the various status codes mean are both complete and
correct
- telegraphic summaries are not usually enough for non-developers to
understand.
Looking at the code you suggested, I also see that the variable names are
the
same as in NTPv3 (and the names imply the original NTPv3 meanings), but the
new
NTPv4 comments on those variables seem to contradict the meanings implied by
the
names. Not knowing the history makes it difficult to figure out just what
is
now meant.
Thanks,
Joe Gwinn
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