Internet Engineering Task Force                                 G. Brown
Internet-Draft                                      CentralNic Group plc
Intended status: Standards Track                               J. Frakes
Expires: May 16, 2016                                  November 13, 2015


  Command Reversal Extension for the Extensible Provisioning Protocol
                                 (EPP)
                       draft-brown-epp-reverse-00

Abstract

   This document describes an Extensible Provisioning Protocol (EPP)
   extension mapping for reversing previous EPP commands.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 16, 2016.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   3
   2.  Extension Elements  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Server Handling of Reverse Commands . . . . . . . . . . . . .   4
   4.  EPP <poll> command  . . . . . . . . . . . . . . . . . . . . .   4
   5.  Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  XML Namespace . . . . . . . . . . . . . . . . . . . . . .   8
     7.2.  EPP Extension Registry  . . . . . . . . . . . . . . . . .   8
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   The Extensible Provisioning Protocol (EPP) provides a way for clients
   to create and update objects in a central repository.  Usually, the
   commands that a client sends to a server will have been initiated
   upon request of a human being.  As a result, occasionally a command
   is sent which contains an error.

   EPP clients have some options to remedy such mistakes: for example,
   they can send a <delete> command to delete an object created in error
   (and may receive a refund if they do so within some grace period),
   cancel a previous <transfer> request, or send an <update> command to
   amend the properties of an object.

   However, there are some circumstances where it is not possible to
   correct an error by using an existing command.  For example, clients
   may inadvertently send multiple <renew> commands (because their
   implementation queries the server for a domain's expiry date, thereby
   defeating the idempotency measures built into EPP) or specify an
   incorrect period (e.g. a two-year renewal which should have only been
   for one year).

   As another example, a client may perform an <update> command on an
   object, but keep no record of the previous state of the object,
   preventing them from correcting the error.

   None of the mistakes in the examples above can be fixed using the
   existing EPP command repertoire.  The extension described in this
   document attempts to provide an additional remedy for such cases, by
   providing a way for a client to request that a previous command be
   reversed.  In order to reverse a command, the client need only record
   the <svTRID> returned by the server in its response to the command.



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1.1.  Conventions Used in This Document

   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 RFC 2119 [RFC2119].

   XML is case sensitive.  Unless stated otherwise, XML specifications
   and examples provided in this document MUST be interpreted in the
   character case presented in order to develop a conforming
   implementation.

   "reverse" is used as an abbreviation for
   "urn:ietf:params:xml:ns:reverse-0.1".  The XML namespace prefix
   "reverse" is used, but implementations MUST NOT depend on it and
   instead employ a proper namespace-aware XML parser and serializer to
   interpret and output the XML documents.

   (Note to RFC Editor: remove the following paragraph before
   publication as an RFC.)

   The XML namespace prefix above contains a version number,
   specifically "0.1".  This version number will increment with
   successive versions of this document, and will reach 1.0 if and when
   this document is published as an RFC.  This permits clients to
   distinguish which version of the extension a server has implemented.

2.  Extension Elements

   This specification provides a new EPP command, called <reverse>.  As
   the set of EPP command verbs cannot be updated without updating the
   core EPP specifications, this command is implemented as an extension.

   When a client wants to reverse a previous command, it sends an EPP
   command frame containing only an <extension> element.  The
   <extension> element contains a <reverse> element, which in turn
   contains the details of the command the client wishes to reverse.
   The <reverse> element has the following child elements:

      An OPTIONAL <reason> element which contains a human-readable
      explanation of why the client is submitting the request.  The
      server MAY require inclusion of a <reason> element depending on
      its own policy.

      A <trID> element which uniquely identifies the command that the
      client wishes to reverse.  The <trID> element is derived from the
      element of the same name in [RFC5730].





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      An OPTIONAL <clTRID> element that uniquely identifies this command
      to the server.

   Example <reverse> request frame:

   C: <?xml version="1.0" encoding="UTF-8"?>
   C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C:   <extension>
   C:     <reverse:reverse
   C:       xmlns:reverse="urn:ietf:params:xml:ns:reverse-0.1">
   C:       <reverse:reason>Reversing an accidental
   C:       double renewal.</reverse:reason>
   C:       <reverse:trID>
   C:         <reverse:clTRID>ABC-10001</reverse:clTRID>
   C:         <reverse:svTRID>54321-XYZ</reverse:svTRID>
   C:       </reverse:trID>
   C:       <reverse:clTRID>ABC-12345</reverse:clTRID>
   C:     </reverse:reverse>
   C:   </extension>
   C: </epp>

3.  Server Handling of Reverse Commands

   Which commands a server will accept <reverse> commands for is a
   matter of server policy (which server operators should provide to
   client operators).  If a server acceps a <reverse> command, it MUST
   respond with a 1000 or 1001 result code.  If the server returns a
   1001 response, the client MUST be notified of outcome of the offline
   process via the EPP message queue.  If the server rejects the
   command, it MUST respond with a 2400 result code.

   Servers MUST NOT allow a client to reverse a command that it did not
   originally submit.  Servers SHOULD implement policies that flag
   <reverse> commands for offline processing where changes might have
   security implications (such as those which would remove client-
   assigned status codes, alter authorisation information or add or
   remove secDNS [RFC5910] records, etc).

   Servers MUST reject a command which attempts to reverse a <reverse>
   command.

4.  EPP <poll> command

   Servers which return 1001 response codes to <reverse> commands MUST
   notify clients of the outcome of the out-of-band process via the EPP
   message queue.  The format of the <poll> message is as follows.





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   The <resData> element of the <poll> response contains a <panData>
   element which contains a <paTRID> element.  This element contains an
   OPTIONAL <clTRID> and a <svTRID> which together identify the
   <reverse> command submitted by the client.  The <paTRID> element has
   a MANDATORY "paResult" element which is a boolean, and which
   indicates the outcome of the offline review.

   The <msg> element contains a human-readable message describing the
   outcome of the review.

   Example of a <poll> message:

   C: <?xml version="1.0" encoding="utf-8" standalone="no"?>
   C: <epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   C:   <response>
   C:     <result code="1301">
   C:       <msg>Command completed successfully; ack to dequeue</msg>
   C:     </result>
   C:     <msgQ count="5" id="12345">
   C:       <qDate>2016-04-04T22:01:00.0Z</qDate>
   C:       <msg>Pending action completed successfully.</msg>
   C:     </msgQ>
   C:     <resData>
   C:       <reverse:panData
   C:         xmlns:reverse="urn:ietf:params:xml:ns:reverse-0.1">
   C:         <reverse:paTRID paResult="1">
   C:           <reverse:clTRID>ABC-12345</reverse:clTRID>
   C:           <reverse:svTRID>54321-XYZ</reverse:svTRID>
   C:         </reverse:paTRID>
   C:         <reverse:paDate>2016-04-04T22:00:00.0Z</reverse:paDate>
   C:       </reverse:panData>
   C:     </resData>
   C:     <trID>
   C:       <clTRID>BCD-23456</clTRID>
   C:       <svTRID>65432-WXY</svTRID>
   C:     </trID>
   C:   </response>
   C: </epp>

5.  Formal Syntax

   An EPP object mapping is specified in XML Schema notation.  The
   formal syntax presented here is a complete schema representation of
   the object mapping suitable for automated validation of EPP XML
   instances.

   Copyright (c) 2015 IETF Trust and the persons identified as authors
   of the code.  All rights reserved.



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   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   o  Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

   o  Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in
      the documentation and/or other materials provided with the
      distribution.

   o  Neither the name of Internet Society, IETF or IETF Trust, nor the
      names of specific contributors, may be used to endorse or promote
      products derived from this software without specific prior written
      permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   BEGIN
   <?xml version="1.0" encoding="UTF-8"?>
   <schema xmlns="http://www.w3.org/2001/XMLSchema"
     xmlns:epp="urn:ietf:params:xml:ns:epp-1.0"
     xmlns:reverse="urn:ietf:params:xml:ns:reverse-0.1"
     targetNamespace="urn:ietf:params:xml:ns:reverse-0.1"
     elementFormDefault="qualified">
     <annotation>
       <documentation>
         Extensible Provisioning Protocol v1.0 extension
         schema for command reverseal.
       </documentation>
     </annotation>

     <import
       namespace="urn:ietf:params:xml:ns:epp-1.0"
       schemaLocation="epp-1.0.xsd"/>

     <!-- command element -->



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     <element name="reverse" type="reverse:reverseType"/>

     <complexType name="reverseType">
       <sequence>
         <element name="reason" type="epp:msgType"
           minOccurs="0" />
           <element name="trID" type="reverse:trIDType"/>
           <element name="clTRID" type="epp:trIDStringType"
             minOccurs="0" />
       </sequence>
     </complexType>

     <complexType name="trIDType">
       <sequence>
         <element name="clTRID" type="epp:trIDStringType"
           minOccurs="0" />
         <element name="svTRID" type="epp:trIDStringType" />
       </sequence>
     </complexType>

     <!-- poll response element -->
     <element name="panData" type="reverse:panDataType" />

     <complexType name="panDataType">
       <sequence>
         <element name="paTRID" type="reverse:paTRIDType" />
         <element name="paDate" type="dateTime" />
       </sequence>
     </complexType>

     <complexType name="paTRIDType">
       <complexContent>
         <extension base="reverse:trIDType">
           <attribute name="paResult" type="boolean" use="required" />
         </extension>
       </complexContent>
     </complexType>

   </schema>
   END

6.  Security Considerations

   The mapping extensions described in this document do not provide any
   security services beyond those described by EPP [RFC5730], and
   protocol layers used by EPP.  The security considerations described
   in these other specifications apply to this specification as well.




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7.  IANA Considerations

7.1.  XML Namespace

   This document uses URNs to describe XML namespaces and XML schemas
   conforming to a registry mechanism described in [RFC3688].  The
   following URI assignment is requested of IANA:

   URI: urn:ietf:params:xml:ns:reverse-0.1

   Registrant Contact: See the "Author's Address" section of this
   document.

   XML: See the "Formal Syntax" section of this document.

7.2.  EPP Extension Registry

   The EPP extension described in this document should be registered by
   the IANA in the EPP Extension Registry described in [RFC7451].  The
   details of the registration are as follows:

   Name of Extension: EPP Reverse Extension

   Document status: Standards Track

   Reference: (insert reference to RFC version of this document)

   Registrant Name and Email Address: See the "Author's Address" section
   of this document.

   TLDs: any

   IPR Disclosure: none

   Status: active

   Notes: none

8.  Acknowledgements

   The authors wish to thank Keith Gaughan for early feedback.

9.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
              RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.



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   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <http://www.rfc-editor.org/info/rfc3688>.

   [RFC5730]  Hollenbeck, S., "Extensible Provisioning Protocol (EPP)",
              STD 69, RFC 5730, DOI 10.17487/RFC5730, August 2009,
              <http://www.rfc-editor.org/info/rfc5730>.

   [RFC5910]  Gould, J. and S. Hollenbeck, "Domain Name System (DNS)
              Security Extensions Mapping for the Extensible
              Provisioning Protocol (EPP)", RFC 5910, DOI 10.17487/
              RFC5910, May 2010,
              <http://www.rfc-editor.org/info/rfc5910>.

   [RFC7451]  Hollenbeck, S., "Extension Registry for the Extensible
              Provisioning Protocol", RFC 7451, DOI 10.17487/RFC7451,
              February 2015, <http://www.rfc-editor.org/info/rfc7451>.

Authors' Addresses

   Gavin Brown
   CentralNic Group plc
   35-39 Moorgate
   London, England  EC2R 6AR
   GB

   Phone: +44 20 33 88 0600
   Email: gavin.brown@centralnic.com
   URI:   https://www.centralnic.com


   Jothan Frakes

   Email: jothan@jothan.com
   URI:   http://jothan.com
















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