< draft-ietf-capport-api-01.txt   draft-ietf-capport-api-02.txt >
Captive Portal Interaction T. Pauly, Ed. Captive Portal Interaction T. Pauly, Ed.
Internet-Draft Apple Inc. Internet-Draft Apple Inc.
Intended status: Standards Track D. Thakore, Ed. Intended status: Standards Track D. Thakore, Ed.
Expires: January 2, 2019 CableLabs Expires: September 12, 2019 CableLabs
July 01, 2018 March 11, 2019
Captive Portal API Captive Portal API
draft-ietf-capport-api-01 draft-ietf-capport-api-02
Abstract Abstract
This document describes an HTTP API that allows hosts to interact This document describes an HTTP API that allows clients to interact
with a Captive Portal system. with a Captive Portal system.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 2, 2019. This Internet-Draft will expire on September 12, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. API Details . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. URI of Captive Portal API endpoint . . . . . . . . . . . 3 4. API Details . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1.1. Server Authentication . . . . . . . . . . . . . . . . 3 4.1. URI of Captive Portal API endpoint . . . . . . . . . . . 3
3.2. JSON Keys . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1.1. Server Authentication . . . . . . . . . . . . . . . . 4
3.3. Example Exchange . . . . . . . . . . . . . . . . . . . . 4 4.2. JSON Keys . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 4.3. An Example Interaction . . . . . . . . . . . . . . . . . 5
4.1. Privacy Considerations . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 5.1. Privacy Considerations . . . . . . . . . . . . . . . . . 6
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
This document describes a HyperText Transfer Protocol (HTTP) This document describes a HyperText Transfer Protocol (HTTP)
Application Program Interface (API) that allows hosts to interact Application Program Interface (API) that allows clients to interact
with a Captive Portal system. The API defined in this document has with a Captive Portal system. The API defined in this document has
been designed to meet the requirements in the Captive Portal been designed to meet the requirements in the Captive Portal
Architecture [I-D.ietf-capport-architecture]. Specifically, the API Architecture [I-D.ietf-capport-architecture]. Specifically, the API
provides: provides:
o The state of captivity (whether or not the host has access to the o The state of captivity (whether or not the client has access to
Internet) the Internet)
o A URI that a host's browser can present to a user to get out of o A URI that a client browser can present to a user to get out of
captivity captivity
o An encrypted connection (TLS for both the API and portal URI) o An encrypted connection (TLS for both the API and portal URI)
2. Workflow 2. Terminology
This document leverages the terminology and components described in
[I-D.ietf-capport-architecture] and additionally uses the following
association:
o Captive Portal Client: The client that interacts with the captive
portal API is typically some application running on the User
Equipment that is connected to the Captive Network. This is also
referred to as the "client" in this document.
o Captive Portal API Server: The server exposing the API's defined
in this document to the client. This is also referred to as the
"API server" in this document.
3. Workflow
The Captive Portal Architecture defines three steps of interaction The Captive Portal Architecture defines three steps of interaction
between hosts and a Captive Portal service: between clients and a Captive Portal service:
1. Provisioning, in which a host discovers that a network has a 1. Provisioning, in which a client discovers that a network has a
captive portal, and learns the URI of the API server captive portal, and learns the URI of the API server
2. API Server interaction, in which a host queries the state of the 2. API Server interaction, in which a client queries the state of
captive portal and retrieves the necessary information to get out the captive portal and retrieves the necessary information to get
of captivity out of captivity
3. Enforcement, in which the enforcement device in the network 3. Enforcement, in which the enforcement device in the network
blocks disallowed traffic, and sends ICMP messages to let hosts blocks disallowed traffic, and sends ICMP messages to let clients
know they are blocked by the captive portal know they are blocked by the captive portal
This document is focused on the second step. It is assumed that the This document is focused on the second step. It is assumed that the
location of the Captive Portal API server has been discovered by the location of the Captive Portal API server has been discovered by the
host as part of the first step. The mechanism for discovering the client as part of the first step. The mechanism for discovering the
API Server endpoint is not covered by this document. API Server endpoint is not covered by this document.
3. API Details 4. API Details
3.1. URI of Captive Portal API endpoint 4.1. URI of Captive Portal API endpoint
The URI of the API endpoint MUST be accessed using HTTP over TLS The URI of the API endpoint MUST be accessed using HTTP over TLS
(HTTPS) and SHOULD be served on port 443 [RFC2818]. The host SHOULD (HTTPS) and SHOULD be served on port 443 [RFC2818]. The client
NOT assume that the URI for a given network attachment will stay the SHOULD NOT assume that the URI for a given network attachment will
same, and SHOULD rely on the discovery or provisioning process each stay the same, and SHOULD rely on the discovery or provisioning
time it joins the network. Depending on how the Captive Portal process each time it joins the network. Depending on how the Captive
system is configured, the URI may be unique for each host and between Portal system is configured, the URI might be unique for each client
sessions for the same host. host and between sessions for the same client host.
For example, if the Captive Portal API server is hosted at For example, if the Captive Portal API server is hosted at
example.org, the URI's of the API could be: example.org, the URI's of the API could be:
o "https://example.org/captive-portal/api" o "https://example.org/captive-portal/api"
o "https://example.org/captive-portal/api/X54PD" o "https://example.org/captive-portal/api/X54PD"
3.1.1. Server Authentication 4.1.1. Server Authentication
The purpose of accessing the Captive Portal API over an HTTPS The purpose of accessing the Captive Portal API over an HTTPS
connection is twofold: first, the encrypted connection protects the connection is twofold: first, the encrypted connection protects the
integrity and confidentiality of the API exchange from other parties integrity and confidentiality of the API exchange from other parties
on the local network; and second, it provides the client of the API on the local network; and second, it provides the client of the API
an opportunity to authenticate the server that is hosting the API. an opportunity to authenticate the server that is hosting the API.
This authentication is aimed at allowing a user to be reasonably This authentication is aimed at allowing a user to be reasonably
confident that the entity providing the Captive Portal API has a confident that the entity providing the Captive Portal API has a
valid certificate for the hostname in the URI (such as valid certificate for the hostname in the URI (such as
"example.com"). The hostname of the API SHOULD be displayed to the "example.com"). The hostname of the API SHOULD be displayed to the
skipping to change at page 4, line 6 skipping to change at page 4, line 27
service. service.
Clients performing revocation checking will need some means of Clients performing revocation checking will need some means of
accessing revocation information for certificates presented by the accessing revocation information for certificates presented by the
API server. Online Certificate Status Protocol [RFC6960] (OCSP) API server. Online Certificate Status Protocol [RFC6960] (OCSP)
stapling, using the TLS Certificate Status Request extension stapling, using the TLS Certificate Status Request extension
[RFC6066] SHOULD be used. OCSP stapling allows a client to perform [RFC6066] SHOULD be used. OCSP stapling allows a client to perform
revocation checks without initiating new connections. To allow for revocation checks without initiating new connections. To allow for
other forms of revocation checking, a captive network could permit other forms of revocation checking, a captive network could permit
connections to OCSP responders or Certificate Revocation Lists (CRLs) connections to OCSP responders or Certificate Revocation Lists (CRLs)
that are referenced by certificates provided by the API server. that are referenced by certificates provided by the API server. In
addition to connections to OCSP responders and CRLs, a captive
network SHOULD also permit connections to Network Time Protocol (NTP)
[RFC5905] servers or other time-sync mechnisms to allow clients to
accurately validate certificates.
Certificates with missing intermediate certificates that rely on Certificates with missing intermediate certificates that rely on
clients validating the certificate chain using the URI specified in clients validating the certificate chain using the URI specified in
the Authority Information Access (AIA) extension [RFC5280] SHOULD NOT the Authority Information Access (AIA) extension [RFC5280] SHOULD NOT
be used by the Captive Portal API server. If the certificates do be used by the Captive Portal API server. If the certificates do
require the use of AIA, the captive network will need to allow client require the use of AIA, the captive network will need to allow client
access to the host specified in the URI. access to the host specified in the URI.
If the client is unable to validate the certificate presented by the If the client is unable to validate the certificate presented by the
API server, it MUST NOT proceed with any of the behavior for API API server, it MUST NOT proceed with any of the behavior for API
interaction described in this document. The client will proceed to interaction described in this document. The client will proceed to
interact with the captive network as if the API capabilities were not interact with the captive network as if the API capabilities were not
present. It may still be possible for the user to access the network present. It may still be possible for the user to access the network
by being redirected to a web portal. by being redirected to a web portal.
3.2. JSON Keys 4.2. JSON Keys
The Captive Portal API data structures are specified in JavaScript The Captive Portal API data structures are specified in JavaScript
Object Notation (JSON) [RFC7159]. Requests and responses for the Object Notation (JSON) [RFC7159]. Requests and responses for the
Captive Portal API use the "application/captive+json" media type. Captive Portal API use the "application/captive+json" media type.
Clients SHOULD include this media type as an Accept header in their Clients SHOULD include this media type as an Accept header in their
GET requests, and servers MUST mark this media type as their Content- GET requests, and servers MUST mark this media type as their Content-
Type header in responses. Type header in responses.
The following keys are defined at the top-level of the JSON structure The following keys are defined at the top-level of the JSON structure
returned by the API server: returned by the API server:
o "permitted" (required, boolean): indicates whether or not the o "captive" (required, boolean): indicates whether the client is in
Captive Portal is open to the requesting host a state of captivity, i.e it has not satisfied the conditions to
access the external network. If the client is captive (i.e.
captive=true), it can still be allowed enough access for it to
perform server authentication Section 4.1.1.
o "user-portal-url" (required, string): provides the URL of a web o "user-portal-url" (required, string): provides the URL of a web
portal that can be presented to a user to interact with portal with which a user can interact.
o "vendor-info-url" (optional, string): provides the URL of a
webpage or site on which the operator of the network has
information that it wishes to share with the user (e.g. store
info, maps, flight status, or entertainment).
o "expire-date" (optional, string formatted as [RFC3339] datetime): o "expire-date" (optional, string formatted as [RFC3339] datetime):
indicates the date and time after which the host will be in a indicates the date and time after which the client will be in a
captive state captive state. The API server SHOULD include this value if the
client is not captive (i.e. captive=false) and SHOULD omit this
value for captive clients.
o "bytes-remaining" (optional, integer): indicates the number of o "bytes-remaining" (optional, integer): indicates the number of
bytes left, after which the host will be in a captive state bytes remaining, after which the client will be in placed into a
captive state.
3.3. Example Exchange 4.3. An Example Interaction
To request the Captive Portal JSON content, a host sends an HTTP GET A client connected to a captive network upon discovering the URI of
the API server will query the API server to retrieve information
about its captive state and conditions to escape captivity. To
request the Captive Portal JSON content, a client sends an HTTP GET
request: request:
GET /captive-portal/api/X54PD GET /captive-portal/api/X54PD
Host: example.org Host: example.org
Accept: application/captive+json Accept: application/captive+json
The server then responds with the JSON content for that client: The server then responds with the JSON content for that client:
HTTP/1.1 200 OK HTTP/1.1 200 OK
Cache-Control: private Cache-Control: private
Date: Mon, 04 Dec 2013 05:07:35 GMT Date: Mon, 04 Dec 2013 05:07:35 GMT
Content-Type: application/captive+json Content-Type: application/captive+json
{ {
"permitted": false, "captive": true,
"user-portal-url": "https://example.org/portal.html" "user-portal-url": "https://example.org/portal.html",
"vendor-info-url": "https://flight.example.com/entertainment",
"expire-date": "2014-01-01T23:28:56.782Z" "expire-date": "2014-01-01T23:28:56.782Z"
} }
4. Security Considerations Upon receiving this information the client will provide this
information to the user so that they may navigate the web portal (as
specified by the user-portal-url value) to enable access to the
external network. Once the user satisfies the requirements for
extenal network access, the client SHOULD query the API server again
to verify that it is no longer captive.
5. Security Considerations
TBD: Provide complete security requirements and analysis. TBD: Provide complete security requirements and analysis.
4.1. Privacy Considerations 5.1. Privacy Considerations
Information passed in this protocol may include a user's personal Information passed in this protocol may include a user's personal
information, such as a full name and credit card details. Therefore, information, such as a full name and credit card details. Therefore,
it is important that Captive Portal API Servers do not allow access it is important that Captive Portal API Servers do not allow access
to the Captive Portal API over unencrypted sessions. to the Captive Portal API over unencrypted sessions.
5. IANA Considerations 6. IANA Considerations
This document registers the media type for Captive Portal API JSON This document registers the media type for Captive Portal API JSON
text, "application/captive+json". text, "application/captive+json".
Type name: application Type name: application
Subtype name: captive+json Subtype name: captive+json
Required parameters: None Required parameters: None
Optional parameters: None Optional parameters: None
Encoding considerations: Encoding considerations are identical to Encoding considerations: Encoding considerations are identical to
those specified for the "application/json" media type. those specified for the "application/json" media type.
Security considerations: See Section 4 Security considerations: See Section 5
Interoperability considerations: This document specifies format of Interoperability considerations: This document specifies format of
conforming messages and the interpretation thereof. conforming messages and the interpretation thereof.
Published specification: This document Published specification: This document
Applications that use this media type: This media type is intended Applications that use this media type: This media type is intended
to be used by servers presenting the Captive Portal API, and to be used by servers presenting the Captive Portal API, and
clients connecting to such captive networks. clients connecting to such captive networks.
Additional information: None Additional information: None
skipping to change at page 6, line 26 skipping to change at page 7, line 26
Authors' Addresses section. Authors' Addresses section.
Intended usage: COMMON Intended usage: COMMON
Restrictions on usage: None Restrictions on usage: None
Author: CAPPORT IETF WG Author: CAPPORT IETF WG
Change controller: IETF Change controller: IETF
6. Acknowledgments 7. Acknowledgments
This work in this document was started by Mark Donnelly and Margaret This work in this document was started by Mark Donnelly and Margaret
Cullen. Thanks to everyone in the CAPPORT Working Group who has Cullen. Thanks to everyone in the CAPPORT Working Group who has
given input. given input.
7. References 8. References
7.1. Normative References 8.1. Normative References
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000, DOI 10.17487/RFC2818, May 2000,
<https://www.rfc-editor.org/info/rfc2818>. <https://www.rfc-editor.org/info/rfc2818>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>. <https://www.rfc-editor.org/info/rfc3339>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/info/rfc5280>.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785, Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010, DOI 10.17487/RFC5785, April 2010,
<https://www.rfc-editor.org/info/rfc5785>. <https://www.rfc-editor.org/info/rfc5785>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS) [RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066, Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011, DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/info/rfc6066>. <https://www.rfc-editor.org/info/rfc6066>.
[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A., [RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,
Galperin, S., and C. Adams, "X.509 Internet Public Key Galperin, S., and C. Adams, "X.509 Internet Public Key
Infrastructure Online Certificate Status Protocol - OCSP", Infrastructure Online Certificate Status Protocol - OCSP",
RFC 6960, DOI 10.17487/RFC6960, June 2013, RFC 6960, DOI 10.17487/RFC6960, June 2013,
<https://www.rfc-editor.org/info/rfc6960>. <https://www.rfc-editor.org/info/rfc6960>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>. 2014, <https://www.rfc-editor.org/info/rfc7159>.
7.2. Informative References 8.2. Informative References
[I-D.ietf-capport-architecture] [I-D.ietf-capport-architecture]
Larose, K. and D. Dolson, "CAPPORT Architecture", draft- Larose, K. and D. Dolson, "CAPPORT Architecture", draft-
ietf-capport-architecture-02 (work in progress), June ietf-capport-architecture-03 (work in progress), December
2018. 2018.
Authors' Addresses Authors' Addresses
Tommy Pauly (editor) Tommy Pauly (editor)
Apple Inc. Apple Inc.
1 Infinite Loop One Apple Park Way
Cupertino, California 95014 Cupertino, California 95014
United States of America United States of America
Email: tpauly@apple.com Email: tpauly@apple.com
Darshak Thakore (editor) Darshak Thakore (editor)
CableLabs CableLabs
858 Coal Creek Circle 858 Coal Creek Circle
Louisville, CO 80027 Louisville, CO 80027
United States of America United States of America
Email: d.thakore@cablelabs.com Email: d.thakore@cablelabs.com
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