RE: Ignore ing

[Andrew.Briscoe@icl.com]

We have adhered to this statement in i500 LDAP but in
a proprietary fashion. I had meant to solicit opinion
from the lists but neglected to do this. I would not
normally choose to go my own way on an issue like this.

We do it in our server/api by allowing a new option to
be set on calls to ber_init(). We chose to name the
option LBER_SEEK_TAGS_MODE and gave it a value of 0x08
following on from the original University of Michigan
(ldap-3.3) allocations of:

LBER_USE_DER            0x01
LBER_USE_INDEFINITE_LEN 0x02
LBER_TRANSLATE_STRINGS  0x04

If this new option has been used then calls to
ber_scanf() will seek out the tags specified in the
ber_scanf format string passively skipping those that do
not satisfy the ber_scanf request.

This seemed to be the easiest way to satisfy the
statement in rfc2251. As it has no external impact on
the LDAP API look and feel and it does not prejudice
v2 LDAP functionality.

It works for us as we use it in our v3 LDAP server.
Real exploitation of the facility is unlikely to be
anything other than our own validation as I do not
know of any protocol that would cause us to have used
it in anger.

I would be interested in any opinions on how this
should be done, and would (of course) be happy for a
strategy like the one mentioned above to be adopted in
some way.

Andrew.


-----Original Message-----
From: Hallvard B Furuseth [mailto:h.b.furuseth@usit.uio.no]
Sent: 13 July 1999 13:33
To: ietf-asid@netscape.com; ietf-ldapext@netscape.com
Subject: Ignore ing


Does anyone actually obey this phrase from rfc2251 section 4?

   "clients and servers MUST ignore elements of SEQUENCE
    encodings whose tags they do not recognize."

I begun to wonder because ber_scanf does not help at all; we have to
read one element at a time and use ber_peek_tag() between each in order
to skip elements with unknown tags.  I suggested two ber_scanf formats
and a ber_skip_tags() function in the C API to help out some time ago,
but got no response.

-- 
Hallvard