openldap/doc/drafts/draft-zeilenga-ldap-cancel-xx.txt

INTERNET-DRAFT                                      Kurt D. Zeilenga
Intended Category: Standard Track                OpenLDAP Foundation
Expires in six months                                    17 May 2002


                      LDAP Cancel Extended Operation
                   <draft-zeilenga-ldap-cancel-05.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
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  Copyright 2002, The Internet Society.  All Rights Reserved.

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


Abstract

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




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Conventions

  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].

  Protocol elements are described using ASN.1 [X.680].  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].


1. Background and Intent of Use

  LDAP [RFC2251] 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.

  X.511 DAP [X.511] 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 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.


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 ::= IANA-ASSIGNED

      cancelRequestValue ::= SEQUENCE {
          cancelID        MessageID
      }


4.1. Cancel Request

  The Cancel request is an ExtendedRequest with the requestName field



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  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
  response fields are absent.


4.3. 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)


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



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  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

    - 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.  IANA Considerations




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7.1.  Object Identifiers

  It is requested that IANA register a Directory Number OID for use in
  this document upon Standards Action by the IESG.   This OID will be
  used to identify the LDAP Cancel extended operation as indicated
  above.  The following registration template is suggested:

      Subject: Request for LDAP OID Registration
      Person & email address to contact for further information:
           Kurt Zeilenga <kurt@OpenLDAP.org>
      Specification: RFCXXX
      Author/Change Controller: IESG


7.2.  LDAP Result Codes

  It is requested that IANA register the LDAP result codes:

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

  upon Standards Action by the IESG.  The following registration
  template is suggested:

      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: RFCXXXX
      Author/Change Controller: IESG
      Comments:  request four consecutive result codes be assigned


8. Acknowledgment

  This document is based upon input from the IETF LDAPext working group.


9. Normative References

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




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  [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.680]   ITU-T, "Abstract Syntax Notation One (ASN.1) - Specification
            of Basic Notation", X.680, 1994.

  [X.690]   ITU-T, "Specification of ASN.1 encoding rules:  Basic,
            Canonical, and Distinguished Encoding Rules", X.690, 1994.


9. Informative References

  [X.511]   ITU-T Rec. X.511, "The Directory: Abstract Service
            Definition", 1993.


11. Author's Address

  Kurt D. Zeilenga
  OpenLDAP Foundation
  <Kurt@OpenLDAP.org>


Copyright 2002, The Internet Society.  All Rights Reserved.

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  ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,



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  INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
  INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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