Internet DRAFT - draft-pauly-httpbis-geoip-hint
draft-pauly-httpbis-geoip-hint
Network Working Group T. Pauly
Internet-Draft Apple Inc.
Intended status: Experimental D. Schinazi
Expires: 1 October 2022 Google LLC
30 March 2022
The IP Geolocation HTTP Client Hint
draft-pauly-httpbis-geoip-hint-00
Abstract
This documents defines an HTTP Client Hint that allows a client to
share information about its IP Geolocation. This helps ensure that
servers have information about location that is consistent with what
a client expects and what other servers use.
Discussion Venues
This note is to be removed before publishing as an RFC.
Source for this draft and an issue tracker can be found at
https://github.com/tfpauly/privacy-proxy.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 1 October 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 3
2. IP Geo Header . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5.1. HTTP Headers . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
HTTP Client Hints [RFC8942] defines a convention for HTTP headers to
communicate optional information from clients to servers as hints.
This can be done conditionally based on if a server claims supports
for a particular hint.
This document defines a client hint that can be used to send a IP
geolocation entry that maps to the client's IP address. This
location can be used to influence server behavior, such as by causing
the server to return responses relevant to the client's location.
The format of the IP geolocation entry is the same as that defined
for IP geolocation feeds in [GEOFEED].
This header is intended to be used to provide rough geolocation hints
to servers that do not already have accurate or authoritative
mappings for the IP addresses of clients. This can be particularly
useful for cases where IP geolocation mappings have changed recently,
or a client is using a VPN or proxy that may not be commonly
recognized by servers.
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The mechanism for how a client learns the IP geolocation mapping to
send is beyond the scope of this document. [RFC9092] defines some
mechanisms for discovery, but clients can also have other mechanisms
(such as coordinating with a VPN or proxy that is assigning the
client a tunnelled or proxied address) to learn what hint to sent.
1.1. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. IP Geo Header
The "Sec-CH-IP-Geo" is an Item Structured Field [STRUCTURED-FIELDS].
The field's value is a String. The string uses the format defined in
Section 2.1.1 of [GEOFEED], with the IP Prefix element removed.
Thus, this contains a comma-separated list of Alpha2code, Region, and
City. The value SHOULD NOT contain a Postal Code.
For example, the header for an entry "192.0.2.5,US,US-AL,Alabaster"
would be:
Sec-CH-IP-Geo = "US,US-AL,Alabaster"
This field also defines a parameter, "feed", that contains the URI of
the IP geolocation feed that is authoritative for this entry. For
example:
Sec-CH-IP-Geo = "SG,SG-01,Singapore"; feed="https://noc.ietf.org/geo/google.csv"
Servers that can provide different content based on Geohash hints
SHOULD include the headers in their "Accept-CH" list.
Accept-CH: Sec-CH-IP-Geo
Servers also SHOULD indicate for any cacheable content if the IP geo
hints will influence the cached content, using the "Vary" header.
Vary: Sec-CH-IP-Geo
3. Server Behavior
Upon receiving a IP Geolocation Client Hint, a server can use the
information to influence its behavior in various ways, such as
determining the content of HTTP responses.
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Many servers have existing IP geolocation feeds that they use to
identify client locations. Servers can choose to use the hint value
in one of several ways:
* Use the client hint information instead of consulting another
geolocation feed.
* Check the value of the "feed" parameter on the header and
determine if it is a trusted feed. If this feed is trusted, but
is not the default feed used by the server, the server can choose
to prefer the feed indicated by the client.
* Check the value of the "feed" parameter on the header and fetch a
copy of the feed to verify the mapping, if a copy of the feed has
not been fetched recently.
* If the feed indicated in the "feed" parameter is unknown or
untrusted, but starts becoming common, the server can flag this
feed as one to be manually checked and added, if appropriate.
This allows servers to automatically discover when new feeds and
services are brought up..
If the server is acting as a forward proxy, such as a CONNECT proxy,
it can use the hint to determine an appropriate geo-mapped IP address
to use for outbound connections, or a client subnet to present in the
EDNS0 Client Subnet extension for DNS queries [RFC6891] [RFC7871].
4. Security Considerations
The use of the IP Geolocation Client Hint MUST use the Sec- header
prefix as recommended in [RFC8942].
Servers MUST NOT use IP Geolocation Client Hints for making security
or access-control decisions, as the value can be spoofed by a client.
The hint is intended only for use in optimizing behavior.
The value contained in this hint SHOULD be based only on a IP
Geolocation feed value for an IP address the client is already
presenting to a server. In order to avoid disclosing any private
information, this value MUST not be based on geolocation of the
client determined by other means, such as physical latitude and
longitude coordinates.
5. IANA Considerations
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5.1. HTTP Headers
This document registers the "Sec-CH-IP-Geo" header in the "Permanent
Message Header Field Names" registry
<https://www.iana.org/assignments/message-headers>.
+----------------------+----------+--------+---------------+
| Header Field Name | Protocol | Status | Reference |
+----------------------+----------+--------+---------------+
| Sec-CH-IP-Geo | http | exp | This document |
+----------------------+----------+--------+---------------+
6. References
6.1. Normative References
[GEOFEED] Kline, E., Duleba, K., Szamonek, Z., Moser, S., and W.
Kumari, "A Format for Self-Published IP Geolocation
Feeds", RFC 8805, DOI 10.17487/RFC8805, August 2020,
<https://www.rfc-editor.org/info/rfc8805>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8942] Grigorik, I. and Y. Weiss, "HTTP Client Hints", RFC 8942,
DOI 10.17487/RFC8942, February 2021,
<https://www.rfc-editor.org/info/rfc8942>.
[STRUCTURED-FIELDS]
Nottingham, M. and P-H. Kamp, "Structured Field Values for
HTTP", RFC 8941, DOI 10.17487/RFC8941, February 2021,
<https://www.rfc-editor.org/info/rfc8941>.
6.2. Informative References
[RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms
for DNS (EDNS(0))", STD 75, RFC 6891,
DOI 10.17487/RFC6891, April 2013,
<https://www.rfc-editor.org/info/rfc6891>.
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[RFC7871] Contavalli, C., van der Gaast, W., Lawrence, D., and W.
Kumari, "Client Subnet in DNS Queries", RFC 7871,
DOI 10.17487/RFC7871, May 2016,
<https://www.rfc-editor.org/info/rfc7871>.
[RFC9092] Bush, R., Candela, M., Kumari, W., and R. Housley,
"Finding and Using Geofeed Data", RFC 9092,
DOI 10.17487/RFC9092, July 2021,
<https://www.rfc-editor.org/info/rfc9092>.
Authors' Addresses
Tommy Pauly
Apple Inc.
One Apple Park Way
Cupertino, California 95014,
United States of America
Email: tpauly@apple.com
David Schinazi
Google LLC
Email: dschinazi.ietf@gmail.com
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