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INTERNET-DRAFT                                      Kurt D. Zeilenga
Intended Category: Standard Track                OpenLDAP Foundation
Expires: 4 August 2001                                 4 August 2001

                      LDAP Cancel Extended Operation

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
  Shadow Directories can be accessed at http://www.ietf.org/shadow.html.

  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 indicatation 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

3.      Background and Intent of Use

  LDAP provides an Abandon operation which clients may use to cancel
  other operations.  The operation does not have a response, hence there
  is no direct indication of success or failure.  The Abandon operation
  also calls for there to be no response of the abandoned 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 X.511

  The Cancel operation is intented 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.


    cancelRequestValue ::= SEQUENCE {
      cancelID        MessageID

4.2.    Cancel Response

  The Cancel request is an ExtendedRequest with the requestName field
  containing cancelOID OID and a requestValue field which contains a
  cancelRequestValue.  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
  response fields are absent.

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4.3.    Additional Result Codes

  Implementations of this specification SHALL recognize the following
  additional resultCodes:

      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 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 outstanding
  operation (if one 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.  Cancel operations themselves are not cancelable.  Abandon,
  Bind, and Unbind operations are not cancelable.  The Start TLS
  [RFC2830] operation is 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

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  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

  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
  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

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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

Zeilenga                                                        [Page 5]

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