option 82 logging error

David W. Hankins David_Hankins at isc.org
Thu Dec 11 17:20:59 UTC 2008

On Thu, Dec 11, 2008 at 09:33:56AM -0600, Marc Perea wrote:
> Anyone know what (808464946:49) this is trying to indicate? Is my
> option82 info too large for the data type of the variable it's being
> placed in?

If you search the archives, you're likely to discover you've got some
clients that are sending malformed VIVCO options (skipping a 'length'
field and going straight on to class contents).  The result is that
the first data octet says the option field is either way longer than
the buffer that contains it, or way shorter, and then more data
contents get parsed as the next "option number" (VIVCO enterprise-ID),
and it's highly unlikely the next 'length' field matches the buffer
length again.

I never thought this log line would be used (I mean, who sends
malformed packet contents, anyway?), so I probably didn't put enough
effort into making sure it was easy to understand.  When parsing a
suboption space, it should tell you the parent space.

Sorry about the logging thing.  log() constructs aren't executed
unless the code calls "execute_statements_in_scope()", which is only
done after a lease is successfully assigned.  We could probably also
stand to do it just before not-offering or NAK'ing a lease, but some
care must be taken since you're not supposed to provide configuration

Likely, all we need to do is nuke the PRL and replace it with a fake
PRL that only includes the one option permitted in a DHCPNAK
(something about disabling link-local addressing).

Ash bugud-gul durbatuluk agh burzum-ishi krimpatul.
Why settle for the lesser evil?	 https://secure.isc.org/store/t-shirt/
David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins
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