INTERNET-DRAFT Kurt D. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation
Expires: 1 October 2001 1 April 2001
LDAP Cancel Extended Operation
<draft-zeilenga-ldap-cancel-03.txt>
1. Status of this Memo
This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.
This document is intended to be, after appropriate review and
revision, submitted to the RFC Editor as a Standard Track document.
Distribution of this memo is unlimited. Technical discussion of this
document will take place on the IETF LDAP Extension Working Group
mailing list <ietf-ldapext@netscape.com>. Please send editorial
comments directly to the author <Kurt@OpenLDAP.org>.
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as ``work in progress.''
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft
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Copyright 2001, The Internet Society. All Rights Reserved.
Please see the Copyright section near the end of this document for
more information.
2. Abstract
This specification describes an extended operation to cancel (or
abandon) an outstanding operation. Unlike the LDAP Abandon operation
[RFC2251] but like the DAP Abandon operation [X.511], this operation
has a response which provides an indication of its outcome.
The key words ``MUST'', ``MUST NOT'', ``REQUIRED'', ``SHALL'', ``SHALL
NOT'', ``SHOULD'', ``SHOULD NOT'', ``RECOMMENDED'', and ``MAY'' in
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this document are to be interpreted as described in RFC 2119
[RFC2119].
3. Background and Intent of Use
LDAP provides an Abandon operation which clients may use to cancel
other operations. The Abandon operation does not have a response and
also calls for there to be no response of the abandoned operation.
These semantics provide the client with no clear indication of the
outcome of the Abandon operation.
DAP provides an Abandon operation which does have a response and also
requires the abandoned operation to return a response with indicating
it was canceled. The Cancel operation is modeled after the DAP
Abandon operation.
The Cancel operation is intended to be used instead of the LDAP
Abandon operation. This operation may be used to cancel both
interrogation and update operations.
4. Cancel Operation
The Cancel operation is defined as a LDAPv3 Extended Operation
[RFC2251, Section 4.12] identified by the OBJECT IDENTIFIER cancelOID.
This section details the syntax of the Cancel request and response
messages and defines additional LDAP resultCodes.
cancelOID OBJECT IDENTIFIER ::= 1.3.6.1.4.1.4203.1.11.2
cancelRequestValue ::= SEQUENCE {
cancelID MessageID
}
4.1. Cancel Request
The Cancel request is an ExtendedRequest with the requestName field
containing cancelOID OID and a requestValue field which contains a
cancelRequestValue value encoded per [RFC2251, Section 5.1]. The
cancelID field contains the message id associated with the operation
to be canceled.
4.2. Cancel Response
A Cancel response is an ExtendedResponse where the responseName and
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response fields are absent.
4.3. Additional Result Codes
Implementations of this specification SHALL recognize the following
additional resultCode values:
canceled (72)
noSuchOperation (73)
tooLate (74)
cannotCancel (75)
5. Operational Semantics
The function of the Cancel Operation is to request that the server
cancel an outstanding operation issued within the same session.
The client requests the cancelation of an outstanding operation by
issuing a Cancel Response with a cancelID with the message id
identifying the outstanding operation. The Cancel Request itself has
a distinct message id. Clients SHOULD NOT request cancelation of an
operation multiple times.
If the server is unable to parse the requestValue or the requestValue
is absent, the server shall return protocolError.
If the server is willing and able to cancel the outstanding operation
identified by the cancelId, the server SHALL return a Cancel Response
with a success resultCode and the canceled operation SHALL fail with
canceled resultCode. Otherwise the Cancel Response SHALL have a
non-success resultCode and SHALL NOT have impact upon the outstanding
operation (if it exists).
The server SHALL return noSuchOperation if it has no knowledge of the
operation requested to be canceled.
The server SHALL return cannotCancel if the identified operation does
not support cancelation or the cancel operation could not be
performed. The following classes of operations are not cancelable:
- operations which have no response,
- operations which associate or disassociate authentication and/or
authorization associations,
- operations which establish or tear-down security services, and
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- operations which abandon or cancel other operations.
Specifically, Abandon, Bind, Start TLS [RFC2830], Unbind and Cancel
operations are not cancelable.
If the result of the outstanding operation has been determined by the
server, the outstanding operation SHALL NOT be canceled and the cancel
operation SHALL result in tooLate.
Servers SHOULD indicate their support for this extended operation by
providing cancelOID as a value of the supportedExtension attribute
type in their root DSE. A server MAY choose to advertise this
extension only when the client is authorized and/or has established
the necessary security protections to use this operation. Clients
SHOULD verify the server implements this extended operation prior to
attempting the operation by asserting the supportedExtension attribute
contains a value of cancelOID.
6. Security Considerations
This operation is intended to allow a user to cancel operations they
previously issued. No user should be allowed to cancel an operation
issued by another user (within the same session or not). However, as
this operation may only be used to cancel within the same session and
LDAP requires operations to be abandoned upon bind requests, this is a
non-issue.
Some operations should not be cancelable for security reasons. This
specification disallows cancelation of Bind operation and Start TLS
extended operation so as to avoid adding complexity to authentication,
authorization, and security layer semantics. Designers of future
extended operations and/or controls SHOULD disallow abandonment and
cancelation when appropriate.
7. Copyright
Copyright 2001, The Internet Society. All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
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Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE AUTHORS, THE INTERNET SOCIETY, AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
8. Bibliography
[RFC2219] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[RFC2251] M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
Protocol (v3)", RFC 2251, December 1997.
[RFC2830] J. Hodges, R. Morgan, and M. Wahl, "Lightweight Directory
Access Protocol (v3): Extension for Transport Layer
Security", RFC 2830, May 2000.
[X.511] ITU-T Rec. X.511, "The Directory: Abstract Service
Definition", 1993. (not normative)
9. Acknowledgment
This document is based upon input from the IETF LDAPext working group.
10. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
<Kurt@OpenLDAP.org>
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