Internet DRAFT - draft-bortzmeyer-dns-json
draft-bortzmeyer-dns-json
Network Working Group S. Bortzmeyer
Internet-Draft AFNIC
Intended status: Experimental February 25, 2013
Expires: August 29, 2013
JSON format to represent DNS data
draft-bortzmeyer-dns-json-01
Abstract
This document describes a profile of JSON to represent DNS data.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on August 29, 2013.
Copyright Notice
Copyright (c) 2013 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
to this document. Code Components extracted from this document must
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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
Bortzmeyer Expires August 29, 2013 [Page 1]
Internet-Draft DNS in JSON February 2013
2. Requirements notation . . . . . . . . . . . . . . . . . . . . 2
3. The format . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. General rules . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Resource records . . . . . . . . . . . . . . . . . . . . 3
3.3. DNS response . . . . . . . . . . . . . . . . . . . . . . 6
3.4. Zone file . . . . . . . . . . . . . . . . . . . . . . . . 7
3.5. Examples . . . . . . . . . . . . . . . . . . . . . . . . 7
3.6. Open questions . . . . . . . . . . . . . . . . . . . . . 8
4. Security considerations . . . . . . . . . . . . . . . . . . . 9
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Normative References . . . . . . . . . . . . . . . . . . 9
5.2. Informative References . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
The JavaScript Object Notation (JSON) format is specified in
[RFC4627]. It is a structured data format suitable for a wide range
of applications. It is specially popular on the Web, due to its
JavaScript roots, but can be found in many other contexts.
The Domain Name System (DNS) is specified in [RFC1034] and [RFC1035].
It is one of the most important infrastructure components of the
Internet. DNS data is today typically exchanged using two formats:
the "zone file" format (partially) described in section 5 of
[RFC1035] and the "wire format" of the section 4 for [RFC1035].
Other formats have been suggested, for an easier exchange of data, or
for using DNS in new applications, such as DNS "looking glasses" or
gateways to get DNS data over protocols such as HTTP ([RFC2616]).
For instance, a mechanism have been suggested for DNS data in XML, in
[I-D.mohan-dns-query-xml].
This document suggests using the JSON format to represent DNS data.
Note that a similar JSON-like (rather than JSON) description of DNS
data already exists in [getdns].
Also note that some representations of DNS data use a data model
which is quite close from the JSON one, even if the concrete syntax
is different (for instance [dnspython]).
2. Requirements notation
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 [RFC2119].
Bortzmeyer Expires August 29, 2013 [Page 2]
Internet-Draft DNS in JSON February 2013
3. The format
3.1. General rules
Most data is represented by JSON objects, with their named members.
It is common to omit some of these members, to save bandwidth or by
pure lazyness. So, clients who consume this sort of JSON objects
should not assume every member is present. THIS IS AN IMPORTANT RULE
(see Section 3.6, Paragraph 2 for a discussion).
3.2. Resource records
DNS resource records are JSON objects. The following members are
common to all record types:
o Name (owner name)
o Type
o Class
o Time to live (TTL)
The other members depend on the record type. The following list
gives the resource record type mnenomic and the JSON members for this
type:
o A:
* Address
o AAAA:
* Address
o MX:
* Preference
* MailExchanger
o NS:
* Target
o PTR:
* Target
Bortzmeyer Expires August 29, 2013 [Page 3]
Internet-Draft DNS in JSON February 2013
o CNAME:
* Target
o SOA:
* MaintainerName
* MasterServerName
* Serial
* Refresh
* Retry
* Expire
* NegativeTtl
o DNSKEY:
* Algorithm
* Length
* Flags
* Tag
o DS:
* DelegationKey
* DigestType
o DLV:
* DelegationKey
* DigestType
o NSEC3PARAM:
* Algorihm
* Flags
Bortzmeyer Expires August 29, 2013 [Page 4]
Internet-Draft DNS in JSON February 2013
* Salt
* Iterations
o SSHFP:
* Algorithm
* DigestType
* Fingerprint
o NAPTR:
* Flags
* Order
* Services
* Preference
* Regexp
* Replacement
o SRV:
* Server
* Port
* Priority
* Weight
o LOC:
* Longitude
* Latitude
* Altitude
o SPF:
* Text
Bortzmeyer Expires August 29, 2013 [Page 5]
Internet-Draft DNS in JSON February 2013
Note there is no concept of resource record sets (see Section 3.6,
Paragraph 3 for a discussion).
3.3. DNS response
A DNS response is represented as a JSON object with a member named
"Query". The main members of this object (the names are self-
explanatory) are:
o QuestionSection
o AnswerSection
o AdditionalSection
o AuthoritySection
o ReturnCode (alphabetical, e.g. NOERROR, NXDOMAIN, SERVFAIL, etc)
o ID
o AA (Authoritative Answer)
o TC (TrunCation)
o RD (Recursion Desired)
o RA (Recursion Available)
o AD (Authentic Data)
o Query
The Question Section is an object with members Qname, Qtype and
Qclass. The other three sections are JSON arrays, each DNS record is
an item in the array. They may be empty arrays (for instance, if the
request returns NOERROR,ANSWER=0, the AnswerSection will be an empty
array).
The Query object has members about the query: Duration is the time
taken to process the request, Server the resolver used (preferably as
an IP address).
Bortzmeyer Expires August 29, 2013 [Page 6]
Internet-Draft DNS in JSON February 2013
3.4. Zone file
A DNS zone file is represented as a JSON object with a member named
"Zone". The main member of this object is an array of resource
records.
The member "Name" cannot be ommitted in resource records (unlike the
text format of [RFC1035], JSON does not guarantee the order of
records, so the trick of "previous resource record" does not work).
But you can use relative names, and @ to denote the origin.
3.5. Examples
{"Query": {"Server": "127.0.0.1"},
"AnswerSection": [
{"Name": "bortzmeyer.fr.",
"TTL": 3600,
"MasterServerName": "ns3.bortzmeyer.org.",
"MaintainerName": "hostmaster.bortzmeyer.org.",
"Serial": 2012060801, "Expire": 604800,
"Refresh": 10800, "Retry": 3600,
"NegativeTTL": 10800,
"Type": "SOA"}],
"ReturnCode": "NOERROR",
"AD": true,
"QuestionSection": {"Qtype": "SOA", "Qname": "bortzmeyer.fr."}}
}
An answer with a SOA resource record
{"Query": {"Duration": "0.167317", "Server": "127.0.0.1"},
"AnswerSection": [
{"Name": "facebook.com", "TTL": 6666, "Type": "AAAA",
"Address": "2a03:2880:10:8f01:face:b00c::25"},
{"Name": "facebook.com", "TTL": 6666, "Type": "AAAA",
"Address": "2a03:2880:2110:3f01:face:b00c::"},
{"Name": "facebook.com", "TTL": 6666, "Type": "AAAA",
"Address": "2a03:2880:10:1f02:face:b00c::25"}],
"ReturnCode": "NOERROR"}
An answer with several resource records
{"Zone": {"Origin": "isi.edu"},
[
{"Type": "SOA", "Name": "@",
"MasterServerName": "venera",
"MaintainerName": "action.domains.",
"Serial": 20},
Bortzmeyer Expires August 29, 2013 [Page 7]
Internet-Draft DNS in JSON February 2013
{"Type": "NS", Name": "@",
"Target": "a.isi.edu"},
{"Type": "NS", Name": "@",
"Target": "venera"},
{"Type": "NS", Name": "@",
"Target": "vaxa"},
{"Type": "MX", Name": "@",
"MailExchanger": "venera",
"Preference": 10},
{"Type": "MX", Name": "@",
"MailExchanger": "vaxa",
"Preference": 20},
{"Type": "A", Name": "a",
"Address": "26.3.0.103"},
{"Type": "A", Name": "venera",
"Address": "10.1.0.52"},
{"Type": "A", Name": "venera",
"Address": "128.9.0.32"}
]
}
The zone file of RFC 1035
3.6. Open questions
Would it be a good idea to document a formal way to derive member
names for the resource record JSON objects? It would allow 1) to
document the rationale for the current names 2) to automatically
allow representation of new DNS resource records. A possible
candidate for such derivation is [I-D.levine-dnsextlang].
Should we define mandatory members for some objects, in order to have
something the consumers can rely on? It seems there is a clear
consensus to do so, making fields with non-default values mandatory.
In resource records objects, members such as TTL are redundant (since
they are actually RRset-wide). Should we have a new level of
objects, for RRsets?
Should we use JSON schema ([I-D.zyp-json-schema] and
[I-D.fge-json-schema-validation]) to define the profile?
Should we add a normative reference to every RFC describing one of
the RR types used here or simply refer to the IANA registry?
Should we have a way to represent unknown RR types, following
[RFC3597]?
Bortzmeyer Expires August 29, 2013 [Page 8]
Internet-Draft DNS in JSON February 2013
How binary data should be represented, for types like DNSKEY? Should
we use Base64 or is the key value an escaped binary string?
4. Security considerations
These JSON documents are not signed (see [I-D.barnes-jose-use-cases])
and therefore not authentified, even if the original data was secured
with DNSSEC. If transported over an insecure transport, they can be
read by a sniffer.
Also, see the security considerations of [RFC4627].
5. References
5.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
5.2. Informative References
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record
(RR) Types", RFC 3597, September 2003.
[I-D.levine-dnsextlang]
Levine, J. and P. Vixie, "An Extension Language for the
DNS", draft-levine-dnsextlang-05 (work in progress),
December 2012.
[I-D.barnes-jose-use-cases]
Barnes, R., "Use Cases and Requirements for JSON Object
Signing and Encryption (JOSE)", draft-barnes-jose-use-
cases-01 (work in progress), October 2012.
[I-D.mohan-dns-query-xml]
Bortzmeyer Expires August 29, 2013 [Page 9]
Internet-Draft DNS in JSON February 2013
Parthasarathy, M. and P. Vixie, "Representing DNS messages
using XML", draft-mohan-dns-query-xml-00 (work in
progress), September 2011.
[I-D.zyp-json-schema]
Galiegue, F., Zyp, K., and G. Court, "JSON Schema: core
definitions and terminology", draft-zyp-json-schema-04
(work in progress), January 2013.
[I-D.fge-json-schema-validation]
Zyp, K. and G. Court, "JSON Schema: interactive and non
interactive validation", draft-fge-json-schema-
validation-00 (work in progress), January 2013.
[getdns] Hoffman, P., "Description of the getdns API", February
2013.
[dnspython]
, "dnspython: A DNS toolkit for Python", February 2013.
Author's Address
Stephane Bortzmeyer
AFNIC
Immeuble International
Saint-Quentin-en-Yvelines 78181
France
Phone: +33 1 39 30 83 46
Email: bortzmeyer+ietf@nic.fr
URI: http://www.afnic.fr/
Bortzmeyer Expires August 29, 2013 [Page 10]