INTERNET-DRAFT Kurt D. Zeilenga Intended Category: Standard Track OpenLDAP Foundation Expires in six months 4 August 2002 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 . Please send editorial comments directly to the author . 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 . The list of Internet-Draft Shadow Directories can be accessed at . 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. Zeilenga LDAP Cancel [Page 1] INTERNET-DRAFT draft-zeilenga-ldap-cancel-06 4 August 2002 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 Zeilenga LDAP Cancel [Page 2] INTERNET-DRAFT draft-zeilenga-ldap-cancel-06 4 August 2002 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 Zeilenga LDAP Cancel [Page 3] INTERNET-DRAFT draft-zeilenga-ldap-cancel-06 4 August 2002 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 Zeilenga LDAP Cancel [Page 4] INTERNET-DRAFT draft-zeilenga-ldap-cancel-06 4 August 2002 7.1. Object Identifiers It is requested that IANA register upon Standards Action an LDAP Object Identifier to identify the LDAP Cancel Extended Operation as defined in this technical specification. The following registration template is suggested: Subject: Request for LDAP OID Registration Person & email address to contact for further information: Kurt Zeilenga Specification: RFCXXX Author/Change Controller: IESG 7.2. LDAP Protocol Mechanism Registration of the protocol mechanisms described in this document is requested [LDAPIANA]. Subject: Request for LDAP Protocol Mechansism Registration Object Identifier: IANA-ASSIGNED Description: extended operation Person & email address to contact for further information: Kurt Zeilenga Usage: Extended Operation Specification: RFCxxxx Author/Change Controller: IESG Comments: none 7.3. LDAP Result Codes It is requested that IANA register upon Standards Action the LDAP result codes: canceled (IANA-ASSIGNED-1) noSuchOperation (IANA-ASSIGNED-2) tooLate (IANA-ASSIGNED-3) cannotCancel (IANA-ASSIGNED-4) The following registration template is suggested: Zeilenga LDAP Cancel [Page 5] INTERNET-DRAFT draft-zeilenga-ldap-cancel-06 4 August 2002 Subject: LDAP Result Code Registration Person & email address to contact for further information: Kurt Zeilenga 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. [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 Zeilenga LDAP Cancel [Page 6] INTERNET-DRAFT draft-zeilenga-ldap-cancel-06 4 August 2002 Copyright 2002, The Internet Society. All Rights Reserved. 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