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Network Working Group                                        K. ZeilengaRequest for Comments: 3909                           OpenLDAP FoundationCategory: Standards Track                                   October 2004Lightweight Directory Access Protocol (LDAP)Cancel OperationStatus of this Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2004).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.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   requires no response from the abandoned operation.  These semantics   provide the client with no clear indication of the outcome of the   Abandon operation.   The X.511 Directory Access Protocol (DAP) [X.511] provides an Abandon   operation which has 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.Zeilenga                    Standards Track                     [Page 1]

RFC 3909                 LDAP Cancel Operation              October 2004   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 inSection 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 inBCP 14 [RFC2119].2.  Cancel Operation   The Cancel operation is defined as an LDAP Extended Operation   [RFC2251,Section 4.12] identified by the object identifier   1.3.6.1.1.8.  This section details the syntax of the Cancel request   and response messages and defines additional LDAP resultCodes.2.1.  Cancel Request   The Cancel request is an ExtendedRequest with the requestName field   containing 1.3.6.1.1.8 and a requestValue field which contains a   BER-encoded cancelRequestValue value.      cancelRequestValue ::= SEQUENCE {          cancelID        MessageID                          -- MessageID is as defined in [RFC2251]      }   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        (118)      noSuchOperation (119)      tooLate         (120)      cannotCancel    (121)Zeilenga                    Standards Track                     [Page 2]

RFC 3909                 LDAP Cancel Operation              October 20043.  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 the 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 an 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 for cancelation.   The cannotCancel resultCode is returned 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 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 Cancel operation cannot be abandoned.   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   has already committed updates to the underlying data store.Zeilenga                    Standards Track                     [Page 3]

RFC 3909                 LDAP Cancel Operation              October 2004   Servers SHOULD indicate their support for this extended operation by   providing 1.3.6.1.1.8 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 a 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 the cancelation of the 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   The following values [RFC3383] have been registered by the IANA.5.1.  Object Identifier   The IANA has registered upon Standards Action the LDAP Object   Identifier 1.3.6.1.1.8 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 3909      Author/Change Controller: IESG      Comments:           Identifies the LDAP Cancel OperationZeilenga                    Standards Track                     [Page 4]

RFC 3909                 LDAP Cancel Operation              October 20045.2.  LDAP Protocol Mechanism   The IANA has registered upon Standards Action the LDAP Protocol   Mechanism described in this document.      Subject: LDAP Protocol Mechanism Registration      Object Identifier: 1.3.6.1.1.8      Description: LDAP Cancel Operation      Person & email address to contact for further information:           Kurt Zeilenga <kurt@openldap.org>      Usage: Extended Operation      Specification:RFC 3909      Author/Change Controller: IESG      Comments: none5.3.  LDAP Result Codes   The IANA has registered 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 (118)      Result Code Name: noSuchOperation (119)      Result Code Name: tooLate (120)      Result Code Name: cannotCancel (121)      Specification:RFC 3909      Author/Change Controller: IESG6.  Acknowledgment   The LDAP Cancel operation is modeled after the X.511 DAP Abandon   operation.Zeilenga                    Standards Track                     [Page 5]

RFC 3909                 LDAP Cancel Operation              October 20047.  References7.1.  Normative References   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [RFC2251]  Wahl, M., Howes, T., and S. Kille, "Lightweight Directory              Access Protocol (v3)",RFC 2251, December 1997.   [RFC2830]  Hodges, J., Morgan, R., 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).7.2.  Informative References   [RFC3383]  Zeilenga, K., "Internet Assigned Numbers Authority (IANA)              Considerations for the Lightweight Directory Access              Protocol (LDAP)",BCP 64,RFC 3383, September 2002.   [X.511]    International Telecommunication Union - Telecommunication              Standardization Sector, "The Directory: Abstract Service              Definition", X.511(1993).8.  Author's Address   Kurt D. Zeilenga   OpenLDAP Foundation   EMail: Kurt@OpenLDAP.orgZeilenga                    Standards Track                     [Page 6]

RFC 3909                 LDAP Cancel Operation              October 20049.  Full Copyright Statement   Copyright (C) The Internet Society (2004).   This document is subject to the rights, licenses and restrictions   contained inBCP 78, and at www.rfc-editor.org, and except as set   forth therein, the authors retain all their rights.   This document and the information contained herein are provided on an   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET   ENGINEERING TASK FORCE DISCLAIM 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.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the ISOC's procedures with respect to rights in ISOC Documents can   be found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at ietf-   ipr@ietf.org.Acknowledgement   Funding for the RFC Editor function is currently provided by the   Internet Society.Zeilenga                    Standards Track                     [Page 7]