Internet DRAFT - draft-lacnic-restwhois-redirects
draft-lacnic-restwhois-redirects
Internet Engineering Task Force C. Martinez, Ed.
Internet-Draft A. Servin, Ed.
Intended status: Informational D. Gomez
Expires: November 17, 2012 G. Rada
LACNIC
May 16, 2012
LACNIC's Redirection Service for Number Resource RESTful WHOIS Queries
draft-lacnic-restwhois-redirects-00
Abstract
The traditional WHOIS protocol has several important shortcomings,
and over the past few years several approaches to a better WHOIS have
been discussed and proposed.
Among these shortcomings, different registries operate different
WHOIS services. For users this implies that several WHOIS queries to
different registries may be necessary in order to obtain data for a
given resource.
This document describes a proof-of-concept redirection service for
RESTful WHOIS queries as implemented by LACNIC. This service allows
users to query a single WHOIS service and be redirected to the
authoritative registry.
The main goal of this document is to encourage discussion on the
topics of Joint WHOIS services and query redirection in a RESTful
WHOIS world.
The solution implemented by LACNIC proposed here applies to numbering
resources (IPv4, IPv6 and autonomous system numbers).
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
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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."
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This Internet-Draft will expire on November 17, 2012.
Copyright Notice
Copyright (c) 2012 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
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described in the Simplified BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Proposed Approach . . . . . . . . . . . . . . . . . . . . . . 4
2.1. The REST approach to web services . . . . . . . . . . . . 4
2.2. Query redirection for RESTful WHOIS queries . . . . . . . 5
2.3. A global Joint WHOIS trough HTTP redirection . . . . . . . 5
2.4. Loops in redirection . . . . . . . . . . . . . . . . . . . 9
3. LACNIC RESTful WHOIS redirector implementation . . . . . . . . 12
3.1. Accessing the redirector . . . . . . . . . . . . . . . . . 12
3.1.1. Redirection URI . . . . . . . . . . . . . . . . . . . 12
4. Security Considerations . . . . . . . . . . . . . . . . . . . 13
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Normative References . . . . . . . . . . . . . . . . . . . 13
5.2. Informative References . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
A user interested in obtaining registration information for a given
number resource normally uses the WHOIS service provided by the RIRs
(AfriNIC, APNIC, ARIN, LACNIC and RIPE-NCC).
In order avoid having to query several databases until obtaining an
answer some approaches have been discussed and implemented in the
past, most notably the Joint WHOIS [lacnic-joint-whois] initiative.
However, among other shortcomings, Joint WHOIS is implemented using
proxies and server-side referrals.
The RESTful approach to WHOIS services
(draft-newton-weirds-arin-whoisrws [I-D.newton-weirds-arin-whoisrws],
draft-newton-rir-query [I-D.newton-et-al-weirds-rir-query],
[draft-lacnic-restful-whois]) makes it comparatively easy to
implement client-side redirects based on normal HTTP 1.1 semantics
and behavior.
The goal of this I-D is to document LACNIC's current implementation
of a RESTful WHOIS redirection service and to encourage discussion on
the topic of redirects in this problem domain.
1.1. Requirements Language
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].
2. Proposed Approach
2.1. The REST approach to web services
While a full introduction to REST and RESTful <http://www.rest.org>
interfaces is out of the scope of this document it is important to
note that these interfaces employ the verbs defined in HTTP (GET,
POST, HEAD, DELETE) and HTTP response codes to signal the semantics
and outcomes of an operation.
As WHOIS is a read-only service only the GET verb is implemented.
HTTP status codes provide signaling for errors and other conditions,
including the concept of "client-side redirection" as outlined below.
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2.2. Query redirection for RESTful WHOIS queries
Each RESTful WHOIS server should answer directly only those queries
for which it is authoritative. In this case, being authoritative
equals "having direct access to a given registry database".
For all other queries, a RESTful WHOIS server could provide a 301
MOVED PERMANENTLY Redirect answer pointing to an URL hosted on a
different RESTful WHOIS server.
Currently the format of the RESTful WHOIS URIs is different across
implementations ([I-D.newton-weirds-arin-whoisrws], RIPE RESTful
Interface [1], [draft-lacnic-restful-whois]), so the redirecting
server implemented by LACNIC currently maps the original query URI to
the URI format expected by the receiving server.
As all requests are to be performed employing HTTP GETs, a user agent
can transparently follow the HTTP 30x redirection hints ([RFC2616])
until obtaining a non-error answer (HTTP 20x) ) or an unrecoverable
error condition (HTTP 40x or 50x).
If the work of WEIRDS progresses far enough so that an uniform URI
format is agreed upon, the need for server-side URI mappings may
become unnecessary.
LACNIC's current implementation splits the authoritative RESTful
WHOIS service from the redirection service. The redirection service
provides a "switching point" for the whole resource tree. No Inter-
RIR coordination, database replication nor RIR-side proxies are
needed.
2.3. A global Joint WHOIS trough HTTP redirection
A single redirection-only RESTful WHOIS server could provide a single
root to which all RIR RESTful WHOIS servers could point queries for
which they are not authoritative.
In LACNIC's implementation the redirect server's database was
initialized from IANA's registries for IPv4, IPv6 and AS numbers.
Implementation was very simple even when adding the server-side URI
mapping requirement outlined above. LACNIC's staff was able to
implement a proof of concept redirect-only server in about two days
of effort including importing IANA's IPv4 registry into a database
and implementing URI mapping for LACNIC, ARIN and RIPE's RESTful
WHOIS services.
Figure 1 shows the general scheme of a single WHOIS redirector
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serving three different RIRs standalone WHOIS while providing a
seamless query interface to clients.
......................
| |
| WHOIS REDIRECTOR |
| |
`....................'
_, | ._
,,' | `.
,-' | `-.
,-' | `._
_,-' | `.
.' | `-.
+-----------Y +-------------. ,------------b
| LACNIC | | RIPE-NCC | | ARIN |
| | | | | |
'`''''''''''' '`'''''''''''' '`''''''''''''
RESTful Joint WHOIS Tree.
Figure 1
Figure 2 shows how HTTP 301 redirection hints guide a client looking
for registration data for the IPv4 address 23.1.1.1 (administered by
ARIN) from LACNIC's WHOIS, the redirector and finally ARIN's WHOIS.
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LACNIC REDIRECTOR ARIN
WHOIS WHOIS WHOIS
. . .
Q: 23.1.1.1? ----> | | |
| | |
<-- HTTP 301 --- | | |
('Try Redirector') | | |
| | |
| | |
Q: 23.1.1.1? -----------------> | |
| |
<---------- HTTP 301 --------| |
('Try ARIN WHOIS') | |
| |
|
Q: 23.1.1.1? -------------------------------> |
|
<---------- HTTP 200 --------------------- |
(WHOIS response is returned) |
|
|
.
Querying WHOIS data for 23.1.1.1
Figure 2
Figure 3 shows the output of the well-known 'wget' tool where the
redirection hints (HTTP 301's) for the same query can be seen.
Figure 3 also shows how the URL mapping function operates,
transforming the LACNIC REST URI into an ARIN REST URI.
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wget --output-document=-
http://restwhois.labs.lacnic.net/restfulwhois/ip/23.1.1.1
--2012-01-10 15:37:46--
http://restwhois.labs.lacnic.net/restfulwhois/ip/23.1.1.1
Resolving restwhois.labs.lacnic.net (restwhois.labs.lacnic.net)...
200.7.84.21
Connecting to restwhois.labs.lacnic.net
(restwhois.labs.lacnic.net)|200.7.84.21|:80... connected.
HTTP request sent, awaiting response... 307 Temporary Redirect
Location: http://www.labs.lacnic.net/restwhois/rwhois_redir/ip/23.1.1.1
[following]
--2012-01-10 15:37:46--
http://www.labs.lacnic.net/restwhois/rwhois_redir/ip/23.1.1.1
Resolving www.labs.lacnic.net (www.labs.lacnic.net)...
2001:13c7:7001:4000::10, 200.7.84.10
Connecting to www.labs.lacnic.net
(www.labs.lacnic.net)|2001:13c7:7001:4000::10|:80... connected.
HTTP request sent, awaiting response... 301 MOVED PERMANENTLY
Location: http://www.labs.lacnic.net/restwhois/rwhois_redir/ip/23.1.1.1/
[following]
--2012-01-10 15:37:46--
http://www.labs.lacnic.net/restwhois/rwhois_redir/ip/23.1.1.1/
Connecting to www.labs.lacnic.net
(www.labs.lacnic.net)|2001:13c7:7001:4000::10|:80... connected.
HTTP request sent, awaiting response... 301 MOVED PERMANENTLY
Location: http://whois.arin.net/rest/ip/23.1.1.1 [following]
--2012-01-10 15:37:46-- http://whois.arin.net/rest/ip/23.1.1.1
Resolving whois.arin.net (whois.arin.net)... 2001:500:31::47,
2001:500:13::46, 2001:500:13::47, ...
Connecting to whois.arin.net (whois.arin.net)|2001:500:31::47|:80...
connected.
HTTP request sent, awaiting response... 200 OK
Length: 1038 (1.0K) [application/xml]
Saving to: `STDOUT'
--- output suppressed for brevity ---
Detailed 'wget' output for a RESTful WHOIS query for 23.1.1.1
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Figure 3
2.4. Loops in redirection
When redirection is used there is always the risk that bogus user-
agents and applications or malicious user can create loops that in
turn may become Denial of Service attacks.
To minimize the risk of loops created by bogus applications and user-
agents operators MAY use the mechanism shown in Section 3.1.
However, this mechanism could be forged and bypassed by malicious
users possibly creating a Denial of Service attack against the
operator. To avoid completely the risk of DoS operators should use
other methods such as rate-limit and authentication that are outside
the scope of this document.
One of the challenges by using redirection is loop avoidance. Even
though recommendation from REFERENCE** indicates that user-agents
should have a mechanism to break loops, due to sometimes not
carefully coded user-agents and other applications or due to
malicious users' activities loops that could end up in a Denial of
Service for the RESTful WHOIS operator.
A simple scenario that creates a loop is shown in Figure 4. An user
request (1) an object from Operator 1; Operator 1 do not have the
object but it has a pointer that Operator 2 has it, so it redirects
(2) the user to Operator 2; user request Object X to Operator 2 (3);
Operator 2 does not have the object either object but it has a
pointer that Operator 1 has it, so it redirects (4) the user to
Operator 1; it creates a loop (5).
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+--------------+ +--------------+
| | | |
| Operator A | | Operator B |
| | | |
+---^-----+----+ +----^----.----+
1) | | 2) 3) | | 4) Redirect
Request | | Redirect Request | | to
Object X | | to Object X | | Operator A
| | Operator B | |
| |____________ _______________| |
|_______________ | | _________________|
| | | |
+--------------+
| | 5) Loop
| User |
| |
+--------------+
A simple loop
Figure 4
The loop described could be avoided by simple forbidding to redirect
a response when the query has been originated by a redirect. However
this solution only allows one redirection. A less restrictive
approach forbidding redirection to only when the destination is the
same than the originator for the redirection does not work either as
shown in Figure 5.
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+--------------+ +--------------+
| | | |
| Operator A | | Operator B |
| | | |
+---^-----+----+ +----^----+----+
1) | | 2) 3) | | 4)Redirect
Request | | Redirect Request | | to
Object X | | to Object X | | Operator C
| | Operator B | |
| |____________ _____________| |
|_______________ | | _______________|
| | | |
+---\/------\/-+
7) Loop | |
| User |
| |
+---^-----+----+
6) Redirect | | 5)
to Operator A | | Request
| | Object X
+--------\/----+
| |
| Operator C |
| |
+--------------+
A more complex loop.
Figure 5
In the scenario depicted in Figure 5 the user request object X from
Operator A which redirects him/her to Operator B which in turn
redirects the user to Operator C. Operator C then redirects the user
back to Operator A again creating a loop.
To avoid loops created by not well-programmed user-agents or
applications when redirecting operators MAY append or modify a
special URI indicating that a redirection and how many times it has
been done. The format of the URI is described in the next section.
In the scenario depicted in Figure 5 the user request object X from
Operator A which redirects him/her to Operator B which in turn
redirects the user to Operator C. Operator C then redirects the user
back to Operator A again creating a loop.
To avoid loops created by not well-programmed user-agents or
applications when redirecting operators MAY append or modify a
special URI indicating that a redirection and how many times it has
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been done. The format of the URI is described in the next section.
3. LACNIC RESTful WHOIS redirector implementation
LACNIC's staff was able to implement a proof-of-concept WHOIS
redirect without committing to a large development effort (around 12
man-hours were consumed).
The redirector was implemented in the Python programming language and
employing the Django web framework library for handling HTTP requests
and responses.
The choice of technology was dictated more by the developers'
familiarity with it. No claim regarding performance or suitability
for a production service is made.
3.1. Accessing the redirector
Currently there are two ways for accessing the redirector:
o By querying LACNIC's RESTful WHOIS for a non-LACNIC resource:
wget --output-document=-
http://restwhois.labs.lacnic.net/restfulwhois/ip/23.1.1.1
o Directly at:
http://www.labs.lacnic.net/restwhois/rwhois_redir
The redirector currently supports queries for IPv4 address blocks
only, employing the REST URIs defined in [!REF:draft-lacnic-
restfulwhois].
The current implementation will provide a redirection to an empty
answer in case the resources are not found in its registry.
LACNIC's current plans currently include extending the redirector so
queries for IPv6 blocks as well as autonomous system numbers are
supported.
3.1.1. Redirection URI
When a RESTful WHOIS operator redirects an user to retrieve an object
from another operator, the operator making the redirection operator
MAY append or modify a special URI.
When using an URI to indicate redirection, the URI MUST have the
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following structure:
/redirect/[step]
Where [step] is a consecutive counter that MUST be increased by every
operator when the URI is encountered in a query object.
When an operator is redirecting a query for the first time it MAY
append the redirection URI to the original URL. If the redirection
URI is used, it MUST use the format previously described and it MUST
set "step" equal to 1. For example, the URL
"http://whois.lacnic.net/restfulwhois/ip/200.7.84.0/24" would be
replaced by
"http://whois.example.com/restfulwhois/ip/200.7.84.0/24/redirect/1"
If an operator receives a request with the redirect URI it first
SHOULD check if "step" is shorter that the defined threshold. If it
does the operator SHOULD strip it and process the query. If the
query requires further redirection the operator MAY use the
redirection URI and it MUST increase "step" in one.
Operators that support the redirect URI MUST never process redirects
that contain a step value greater that their locally set threshold.
4. Security Considerations
This document makes no explicit security considerations other than
those stated above.
5. References
5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[min_ref] authSurName, authInitials., "Minimal Reference", 2006.
5.2. Informative References
[I-D.newton-et-al-weirds-rir-query]
Newton, A., Ranjbar, K., and A. Servin, "A Uniform RESTful
URL Query Pattern for RIRs",
draft-newton-et-al-weirds-rir-query-00 (work in progress),
September 2011.
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[I-D.newton-weirds-arin-whoisrws]
Newton, A., "ARIN's RESTful Web Service for Whois Data",
draft-newton-weirds-arin-whoisrws-00 (work in progress),
June 2011.
[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.
[draft-lacnic-restful-whois]
LACNIC, "LACNIC's RESTful WHOIS Interface for Registry
Data", 2011, <http://www.labs.lacnic.net/site/sites/
default/files/draft-lacnic-weirds-restwhois-03.pdf>.
[lacnic-joint-whois]
LACNIC, "Joint WHOIS", 2005, <ftp://
anonymous@ftp.registro.br/pub/gter/gter20/
02-jwhois-lacnic.pdf>.
URIs
[1] <https://labs.ripe.net/ripe-database/database-api/
api-documentation>
Authors' Addresses
Carlos M. Martinez (editor)
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: carlos@lacnic.net
Arturo L. Servin (editor)
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: aservin@lacnic.net
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Dario Gomez
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: dario@lacnic.net
Gerardo Rada
LACNIC
Rambla Mexico 6125
Montevideo, 11400
Uruguay
Phone: +598-2604-2222
Email: gerardo@lacnic.net
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