





INTERNET-DRAFT                                      Kurt D. Zeilenga
Intended Category: Standard Track                OpenLDAP Foundation
Expires in six months                                25 October 2003


                          LDAP Cancel Operation
                   <draft-zeilenga-ldap-cancel-10.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 Extensions mailing list
  <ldapext@ietf.org>.  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
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  <http://www.ietf.org/shadow.html>.

  Copyright (C) The Internet Society (2003).  All Rights Reserved.

  Please see the Full Copyright section near the end of this document
  for more information.


Abstract

  This specification describes a Lightweight Directory Access Protocol
  (LDAP) extended operation to cancel (or abandon) an outstanding
  operation.   Unlike the LDAP Abandon operation but like the X.511
  Directory Access Protocol (DAP) Abandon operation, this operation has
  a response which provides an indication of its outcome.




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Terminology

  Protocol elements are described using ASN.1 [X.680] with implicit
  tags.  The term "BER-encoded" means the element is to be encoded using
  the Basic Encoding Rules [X.690] under the restrictions detailed in
  Section 5.1 of [RFC2251].

  DSA stands for Directory System Agent (or server).
  DSE stands for DSA-specific Entry.

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
  document are to be interpreted as described in BCP 14 [RFC2119].


1. Background and Intent of Use

  The Lightweight Directory Access Protocol (LDAP) [RFC3377] provides an
  Abandon operation [RFC2251] which clients may use to cancel other
  operations.  The Abandon operation does not have a response and 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.

  X.511 Directory Access Protocol (DAP) [X.511] provides an Abandon
  operation which does have a response and also requires the abandoned
  operation to return a response indicating it was canceled.  The LDAP
  Cancel operation is modeled after the DAP Abandon operation.

  The LDAP Cancel operation SHOULD be used instead of the LDAP Abandon
  operation when the client needs an indication of the outcome.  This
  operation may be used to cancel both interrogation and update
  operations.


2. Cancel Operation

  The Cancel operation is defined as a LDAP Extended Operation [RFC2251,
  Section 4.12] identified by the IANA-ASSIGNED-OID.  This section
  details the syntax of the Cancel request and response messages and
  defines additional LDAP resultCodes.

      cancelRequestValue ::= SEQUENCE {
          cancelID        MessageID
      }


2.1. Cancel Request



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  The Cancel request is an ExtendedRequest with the requestName field
  containing the IANA-ASSIGNED-OID and a requestValue field which
  contains a BER-encoded cancelRequestValue value.  The cancelID field
  contains the message id associated with the operation to be canceled.


2.2. Cancel Response

  A Cancel response is an ExtendedResponse where the responseName and
  response fields are absent.


2.3. Additional Result Codes

  Implementations of this specification SHALL recognize the following
  additional resultCode values:

      canceled        (IANA-ASSIGNED-1)
      noSuchOperation (IANA-ASSIGNED-2)
      tooLate         (IANA-ASSIGNED-3)
      cannotCancel    (IANA-ASSIGNED-4)


3. 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 set to the message id of 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 the outstanding
  operation (if it exists).

  The protocolError resultCode is returned if the server is unable to
  parse the requestValue or the requestValue is absent,

  The noSuchOperation resultCode is returned if the server has no
  knowledge of the operation requested to be canceled.

  The cannotCancel resultCode is returned if the identified operation



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  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 create, alter, or destroy authentication and/or
      authorization associations,

    - operations which establish, alter, or tear-down security services,
      and

    - operations which abandon or cancel other operations.

  Specifically, the Abandon, Bind, Start TLS [RFC2830], Unbind and
  Cancel operations are not cancelable.

  The tooLate resultCode is returned to indicate that it is too late to
  cancel the outstanding operation.  For example, the server may return
  tooLate for a request to cancel an outstanding modify operation which
  as already committed updates to the underlying data store.

  Servers SHOULD indicate their support for this extended operation by
  providing IANA-ASSIGNED-OID 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 to use it.


4. Security Considerations

  This operation is intended to allow user to cancel operations they
  previously issued during the current LDAP association.  In certain
  cases, such as when the Proxy Authorization Control is in use,
  different outstanding operations may be processed under different LDAP
  associations.  Servers MUST NOT allow a user to cancel an operation
  belonging to another user.

  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.


5.  IANA Considerations

  Registration of the following values [RFC3383] is requested.




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5.1.  Object Identifier

  It is requested that IANA register upon Standards Action an LDAP
  Object Identifier to identify the LDAP Cancel Operation as defined in
  this document.

      Subject: Request for LDAP Object Identifier Registration
      Person & email address to contact for further information:
           Kurt Zeilenga <kurt@OpenLDAP.org>
      Specification: RFC XXXX
      Author/Change Controller: IESG
      Comments:
           Identifies the LDAP Cancel Operation


5.2.  LDAP Protocol Mechanism

  It is requested that IANA register upon Standards Action the LDAP
  Protocol Mechanism described in this document.

      Subject: Request for LDAP Protocol Mechanism Registration
      Object Identifier: IANA-ASSIGNED-OID
      Description: LDAP Cancel Operation
      Person & email address to contact for further information:
           Kurt Zeilenga <kurt@openldap.org>
      Usage: Extended Operation
      Specification: RFC XXXX
      Author/Change Controller: IESG
      Comments: none
      in 2


5.3.  LDAP Result Codes

      It is requested that IANA register upon Standards Action the LDAP
      Result Codes described in this document.

      Subject: LDAP Result Code Registration
      Person & email address to contact for further information:
           Kurt Zeilenga <kurt@OpenLDAP.org>
      Result Code Name: canceled
      Result Code Name: noSuchOperation
      Result Code Name: tooLate
      Result Code Name: cannotCancel
      Specification: RFC XXXX
      Author/Change Controller: IESG
      Comments:  request four consecutive result codes be assigned




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6. Acknowledgment

  The LDAP Cancel operation is modeled after the X.511 DAP Abandon
  operation.


7. Normative References

  [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14 (also RFC 2119), March 1997.

  [RFC2251]     Wahl, M., T. Howes and S. Kille, "Lightweight Directory
                Access Protocol (v3)", RFC 2251, December 1997.

  [RFC2830]     Hodges, J., R. Morgan, and M. Wahl, "Lightweight
                Directory Access Protocol (v3): Extension for Transport
                Layer Security", RFC 2830, May 2000.

  [RFC3377]     Hodges, J. and R. Morgan, "Lightweight Directory Access
                Protocol (v3): Technical Specification", RFC 3377,
                September 2002.

  [X.680]       International Telecommunication Union -
                Telecommunication Standardization Sector, "Abstract
                Syntax Notation One (ASN.1) - Specification of Basic
                Notation", X.680(1997) (also ISO/IEC 8824-1:1998).

  [X.690]       International Telecommunication Union -
                Telecommunication Standardization Sector, "Specification
                of ASN.1 encoding rules: Basic Encoding Rules (BER),
                Canonical Encoding Rules (CER), and Distinguished
                Encoding Rules (DER)", X.690(1997) (also ISO/IEC
                8825-1:1998).


8. Informative References

  [RFC3383]     Zeilenga, K., "IANA Considerations for LDAP", BCP 64
                (also RFC 3383), September 2002.

  [X.511]       International Telecommunication Union -
                Telecommunication Standardization Sector, "The
                Directory: Abstract Service Definition", X.511(1993).


9. Author's Address

  Kurt D. Zeilenga



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  OpenLDAP Foundation
  <Kurt@OpenLDAP.org>



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Full Copyright

  Copyright (C) The Internet Society (2003). All Rights Reserved.

  This document and translations of it may be copied and furnished to
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