Network Working Group K. Zeilenga
Request for Comments: 4525 OpenLDAP Foundation
Category: Informational June 2006
Lightweight Directory Access Protocol (LDAP)
Modify-Increment Extension
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document describes an extension to the Lightweight Directory
Access Protocol (LDAP) Modify operation to support an increment
capability. This extension is useful in provisioning applications,
especially when combined with the assertion control and/or the pre-
read or post-read control extension.
Table of Contents
1. Background and Intended Use .....................................1
2. The Modify-Increment Extension ..................................2
3. LDIF Support ....................................................2
4. Security Considerations .........................................3
5. IANA Considerations .............................................3
5.1. Object Identifier ..........................................3
5.2. LDAP Protocol Mechanism ....................................3
5.3. LDAP Protocol Mechanism ....................................4
6. References ......................................................4
6.1. Normative References .......................................4
6.2. Informative References .....................................5
1. Background and Intended Use
The Lightweight Directory Access Protocol (LDAP) [RFC 4510] does not
currently provide an operation to increment values of an attribute.
A client must read the values of the attribute and then modify those
values to increment them by the desired amount. As the values may be
updated by other clients between this add and modify, the client must
Zeilenga Informational [Page 1]
RFC 4525 LDAP Modify-Increment Extension June 2006
be careful to construct the modify request so that it fails in this
case, and upon failure, to re-read the values and construct a new
modify request.
This document extends the LDAP Modify Operation [RFC 4511] to support
an increment values capability. This feature is intended to be used
with either the LDAP pre-read or post-read control extensions
[RFC 4527]. This feature may also be used with the LDAP assertion
control extension [RFC 4528] to provide test-and-increment
functionality.
In this document key words "MUST", "MUST NOT", "REQUIRED", "SHALL",
"SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
"OPTIONAL" are to be interpreted as described in BCP 14 [RFC 2119].
2. The Modify-Increment Extension
This document extends the LDAP Modify request to support a increment
values capability. Implementations of this extension SHALL support
an additional ModifyRequest operation enumeration value increment
(3), as described herein. Implementations not supporting this
extension will treat this value as they would an unlisted value,
e.g., as a protocol error.
The increment (3) operation value specifies that an increment values
modification is requested. All existing values of the modification
attribute are to be incremented by the listed value. The
modification attribute must be appropriate for the request (e.g., it
must have INTEGER or other increment-able values), and the
modification must provide one and only one value. If the attribute
is not appropriate for the request, a constraintViolation or other
appropriate error is to be returned. If multiple values are
provided, a protocolError is to be returned.
Servers supporting this feature SHOULD publish the object identifier
(OID) 1.3.6.1.1.14 as a value of the 'supportedFeatures' [RFC 4512]
attribute in the root DSE. Clients supporting this feature SHOULD
NOT use the feature unless they know the server supports it.
3. LDIF Support
To represent Modify-Increment requests in LDAP Data Interchange
Format [RFC 2849], the ABNF [RFC 4234] production <mod-spec> is
extended as follows:
mod-spec =/ "increment:" FILL AttributeDescription SEP
attrval-spec "-" SEP
Zeilenga Informational [Page 2]
RFC 4525 LDAP Modify-Increment Extension June 2006
For example,
# Increment uidNumber
dn: cn=max-assigned uidNumber,dc=example,dc=com
changetype: modify
increment: uidNumber
uidNumber: 1
-
This LDIF fragment represents a Modify request to increment the
value(s) of uidNumber by 1.
4. Security Considerations
General LDAP security considerations [RFC 4510], as well as those
specific to the LDAP Modify [RFC 4511], apply to this Modify-Increment
extension. Beyond these considerations, it is noted that
introduction of this extension should reduce application complexity
(by providing one operation for what presently requires multiple
operations) and, hence, it may aid in the production of correct and
secure implementations.
5. IANA Considerations
Registration of the following values [RFC 4520] have been completed.
5.1. Object Identifier
The IANA has assigned an LDAP Object Identifier to identify the LDAP
Modify-Increment feature, 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 4525
Author/Change Controller: Author
Comments:
Identifies the LDAP Modify-Increment feature
5.2. LDAP Protocol Mechanism
The following LDAP Protocol Mechanism has been registered.
Subject: Request for LDAP Protocol Mechanism Registration
Object Identifier: 1.3.6.1.1.14
Description: Modify-Increment
Person & email address to contact for further information:
Kurt Zeilenga <kurt@openldap.org>
Zeilenga Informational [Page 3]
RFC 4525 LDAP Modify-Increment Extension June 2006
Usage: Feature
Specification: RFC 4525
Author/Change Controller: Kurt Zeilenga <kurt@openldap.org>
Comments: none
5.3. LDAP Protocol Mechanism
The IANA has assigned an LDAP ModifyRequest Operation Type (3)
[RFC 4520] for use in this document.
Subject: Request for LDAP Protocol Mechanism Registration
ModifyRequest Operation Name: increment
Description: Modify-Increment
Person & email address to contact for further information:
Kurt Zeilenga <kurt@openldap.org>
Usage: Feature
Specification: RFC 4525
Author/Change Controller: Kurt Zeilenga <kurt@openldap.org>
Comments: none
6. References
6.1. Normative References
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 4234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 4234, October 2005.
[RFC 2849] Good, G., "The LDAP Data Interchange Format (LDIF) -
Technical Specification", RFC 2849, June 2000.
[RFC 4510] Zeilenga, K., Ed., "Lightweight Directory Access
Protocol (LDAP): Technical Specification Road Map", RFC
4510, June 2006.
[RFC 4511] Sermersheim, J., Ed., "Lightweight Directory Access
Protocol (LDAP): The Protocol", RFC 4511, June 2006.
[RFC 4512] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP): Directory Information Models", RFC 4512, June
2006.
Zeilenga Informational [Page 4]
RFC 4525 LDAP Modify-Increment Extension June 2006
6.2. Informative References
[RFC 4520] Zeilenga, K., "Internet Assigned Numbers Authority
(IANA) Considerations for the Lightweight Directory
Access Protocol (LDAP)", BCP 64, RFC 4520, June 2006.
[RFC 4527] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP) Read Entry Controls", RFC 4527, June 2006.
[RFC 4528] Zeilenga, K., "Lightweight Directory Access Protocol
(LDAP) Assertion Control", RFC 4528, June 2006.
Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
EMail: Kurt@OpenLDAP.org
Zeilenga Informational [Page 5]
RFC 4525 LDAP Modify-Increment Extension June 2006
Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, 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 procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 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 at
http://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 provided by the IETF
Administrative Support Activity (IASA).
Zeilenga Informational [Page 6]