[Opendnssec-user] Zone stuck, not updating

Havard Eidnes he at uninett.no
Fri Oct 31 16:24:05 UTC 2014


> It seems that the problem is that the SOA version number used in
> the IXFR request is totally "off the wall"; I'm seeing
> 3180924024, which is way bigger than what's in the .xfrd-state
> file (2014091709), but still "bigger" according to the serial
> number arithmetic used for SOA version numbers.

Ding, found the bug which caused toe odd-looking SOA serial
number.  Someone has been running on autopilot...

xfrd_recover() in signer/src/wire/xfrd.c which restores the data
for a zone from the .xfrd-state file contains this piece of code:

                /* all ok */
...
                xfrd->soa.ttl = htonl(soa_ttl);
                xfrd->soa.serial = htonl(soa_serial);
                xfrd->soa.refresh = htonl(soa_refresh);
                xfrd->soa.retry = htonl(soa_retry);
                xfrd->soa.expire = htonl(soa_expire);
                xfrd->soa.minimum = htonl(soa_minimum);
...

Um, why the htonl() invocations?!?  This is data written to and
read from a local file, so on a little-endian machine, a byte-
swap should not be needed.

Byte-swapping the "strange" serial number:

% dc
3180924024 16op
BD990C78
q
% dc
16i
780C99BDp
2014091709
q
%

gives us back what it should have been in the first place.

And of course when I fix this bug, the byte-swapped version of
the SOA serial has already been written to the *.xfrd-state
files, forcing me to stop OpenDNSSEC, remove all the *.xfrd-state
files, and restart it.

Hopefully *that* should fix the problem permanently.

Well...

It seems that some other files in my /var/opendnssec/tmp/ also
needed removing (ixfr state files messed up?), so I stopped
OpenDNSSEC, renamed the dir and re-created it and then restarted
OpenDNSSEC.  Things seem to be back on track again.

Now I just need to write that monitoring script so that I can be
alerted if this should ever happen again -- hopefully it won't.

Best regards,

- Håvard



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