Internet DRAFT - draft-cms-masque-ip-proxy-reqs
draft-cms-masque-ip-proxy-reqs
Network Working Group A. Chernyakhovsky
Internet-Draft D. McCall
Intended status: Informational D. Schinazi
Expires: 8 February 2021 Google LLC
7 August 2020
Requirements for a MASQUE Protocol to Proxy IP Traffic
draft-cms-masque-ip-proxy-reqs-01
Abstract
There is interest among MASQUE working group participants in
designing a protocol that can proxy IP traffic over HTTP. This
document describes the set of requirements for such a protocol.
Discussion of this work is encouraged to happen on the MASQUE IETF
mailing list masque@ietf.org or on the GitHub repository which
contains the draft: https://github.com/DavidSchinazi/masque-drafts.
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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time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on 8 February 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Definitions . . . . . . . . . . . . . . . . . . . . . . . 3
2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Consumer VPN . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Point to Point Connectivity . . . . . . . . . . . . . . . 4
2.3. Point to Network Connectivity . . . . . . . . . . . . . . 4
2.4. Network to Network Connectivity . . . . . . . . . . . . . 4
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. IP Session Establishment . . . . . . . . . . . . . . . . 5
3.2. Proxying of IP packets . . . . . . . . . . . . . . . . . 5
3.3. Maximum Transmission Unit . . . . . . . . . . . . . . . . 5
3.4. IP Assignment . . . . . . . . . . . . . . . . . . . . . . 5
3.5. Route Negotiation . . . . . . . . . . . . . . . . . . . . 5
3.6. Identity . . . . . . . . . . . . . . . . . . . . . . . . 5
3.7. Transport Security . . . . . . . . . . . . . . . . . . . 6
3.8. Authentication . . . . . . . . . . . . . . . . . . . . . 6
3.9. Reliable Transmission of IP Packets . . . . . . . . . . . 6
3.10. Flow Control . . . . . . . . . . . . . . . . . . . . . . 6
3.11. Indistinguishability . . . . . . . . . . . . . . . . . . 6
3.12. Support HTTP/2 and HTTP/3 . . . . . . . . . . . . . . . . 7
3.13. Multiplexing . . . . . . . . . . . . . . . . . . . . . . 7
3.14. Load balancing . . . . . . . . . . . . . . . . . . . . . 7
3.15. Extensibility . . . . . . . . . . . . . . . . . . . . . . 7
4. Non-requirements . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Addressing Architecture . . . . . . . . . . . . . . . . . 8
4.2. Translation . . . . . . . . . . . . . . . . . . . . . . . 8
4.3. IP Packet Extraction . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 8
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Normative References . . . . . . . . . . . . . . . . . . . . . 9
Informative References . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
There exist several IETF standards for proxying IP in a way that is
authenticated and confidential, such as IKEv2/IPsec [IKEV2].
However, those are distinguishable from common Internet traffic and
often blocked. Additionally, large server deployments have expressed
interest in using a VPN solution that leverages existing security
protocols such as QUIC [QUIC] or TLS [TLS] to avoid adding another
protocol to their security posture.
This document describes the set of requirements for a protocol that
can proxy IP traffic over HTTP. The requirements outlined below are
similar to the considerations made in designing the CONNECT-UDP
method [CONNECT-UDP], additionally including IP-specific
requirements, such as a means of negotiating the routes that should
be advertised on either end of the connection.
Discussion of this work is encouraged to happen on the MASQUE IETF
mailing list masque@ietf.org or on the GitHub repository which
contains the draft: https://github.com/DavidSchinazi/masque-drafts.
1.1. Conventions
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.
1.2. Definitions
* Data Transport: The method by which IP packets are transmitted.
This can involve streams or datagrams.
* IP Session: An association between client and server whereby both
agree to proxy IP traffic given certain configuration properties.
This is similar to a Child Security Association in IKEv2
terminology.
2. Use Cases
There are multiple reasons to deploy an IP proxying protocol. This
section discusses some examples of use cases that MUST be supported
by the protocol.
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2.1. Consumer VPN
Consumer VPNs refer to network applications that allow a user to hide
some properties of their traffic from some network observers. In
particular, it can hide the identity of servers the client is
connecting to from the client's network provider, and can hide the
client's IP address (and derived geographical information) from the
servers they are communicating with. Note that this hidden
information is now available to the VPN service provider, so is only
beneficial for clients who trust the VPN service provider more than
other entities.
2.2. Point to Point Connectivity
Point-to-point connectivity creates a private, encrypted and
authenticated network between two IP addresses. This is useful, for
example, with container networking to provide a virtual (overlay)
network with addressing separate from the physical transport. An
example of this is Wireguard.
2.3. Point to Network Connectivity
Point-to-Network connectivity is the more traditional remote-access
"VPN" use case, frequently used when a user needs to connect to a
different network (such as an enterprise network) for access to
resources that are not exposed to the public Internet.
2.4. Network to Network Connectivity
Network-to-Network connectivity is also called a site-to-site VPN.
Like the point-to-network use case, the goal is to connect to a
network that is not exposed publicly. The site-to-site aspects make
this transparent to the user; the entire networks are connected to
each other and route packets transparently without a VPN client
installed on the user's device. This style of connectivity can also
be used to connect devices that cannot run VPN clients through to the
network.
3. Requirements
This section lists requirements for a protocol that can proxy IP over
an HTTP connection.
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3.1. IP Session Establishment
The protocol will allow the client to request establishment of an IP
Session, along with configuration options and one or more associated
Data Transports. The server will have the ability to accept or deny
the client's request.
3.2. Proxying of IP packets
The protocol will establish Data Transports, which will be able to
forward IP packets, in their unmodified entirety. The protocol will
support both IPv6 [IPV6] and IPv4 [IPV4].
3.3. Maximum Transmission Unit
The protocol will allow endpoints to inform each other of the Maximum
Transmission Unit (MTU) they are willing to forward. This will allow
avoiding IP fragmentation, especially as IPv6 does not allow IP
fragmentation by nodes along the path.
3.4. IP Assignment
The client will be able to request to be assigned an IP address
range, optionally specifying a preferred range. In response to that
request, the server will either assign a range of its choosing to the
client, or decline the request. Similarly, to support the network-
to-network use case, the server will be able to request assignment of
an IP address range from the client, and the client will either
assign a range or decline the request.
3.5. Route Negotiation
At any point in an IP Session (not limited to its initial
negotiation), the protocol will allow both client and server to
inform its peer that it can route a set of IP prefixes. Both
endpoints can also request a route to a given prefix, and the peer
can choose to provide that route or not.
3.6. Identity
When negotiating the creation of an IP Session, the protocol will
allow both endpoints to exchange an identifier. For example, both
endpoints will be able to identify themselves by sending a fully-
qualified domain name. Note that the Identity requirement does not
cover authenticating the identifier; that requirement is covered by
Section 3.8.
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3.7. Transport Security
The protocol MUST be run over a protocol that provides mutual
authentication, confidentiality and integrity. Using QUIC or TLS
would meet this requirement.
3.8. Authentication
Additionally to the authentication provided by the transport, the
protocol will have the ability to authenticate both client and server
during the establishment of the IP Session. In particular, it will
be possible for the client to offer an OAuth Access Token [OAUTH] to
the server when requesting IP proxying, potentially through an
extension of the protocol. The protocol will also have the ability
to support vendor-specific authentication mechanisms as extensions.
3.9. Reliable Transmission of IP Packets
While it is desirable to transmit IP packets unreliably in most
cases, the protocol will provide a mechanism to allow forwarding some
packets reliably. For example, when using HTTP/3, this can be
accomplished by allowing Data Transports to run over both DATAGRAM
and STREAM frames.
3.10. Flow Control
The protocol will allow the ability to proxy IP packets without flow
control, at least when HTTP/3 is in use. QUIC DATAGRAM frames are
not flow controlled and would meet this requirement. The document
defining the protocol will provide guidance on how best to use flow
control to improve IP Session performance.
3.11. Indistinguishability
A passive network observer not participating in the encrypted
connection should not be able to distinguish an IP proxying session
from regular encrypted HTTP Web traffic. Specifically, any data sent
unencrypted (such as headers, or parts of the handshake) should look
like the same unencrypted data that would be present for Web traffic.
Traffic analysis is out of scope for this requirement.
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3.12. Support HTTP/2 and HTTP/3
The IP proxying protocol discussed in this document will run over
HTTP. The protocol SHOULD strongly prefer to use HTTP/3 [H3] and
SHOULD use the QUIC DATAGRAM frames [DGRAM] when available to improve
performance. The protocol SHOULD also support HTTP/2 [H2] as a
fallback when UDP is blocked on the network path. Proxying IP over
HTTP/2 MAY result in lower performance than over HTTP/3.
3.13. Multiplexing
Since recent HTTP versions support concurrently running multiple
requests over the same connection, the protocol SHOULD support
multiple independent instances of IP proxying over a given HTTP
connection.
3.14. Load balancing
Clients and servers should each be able to instantiate new Data
Transports. This facilitates multi-threaded servers being able to
handle a higher bandwidth of IP proxied packets.
The IP proxying mechanisms need to support load balancing of the
traffic sent across the session, such as to another server. The
document defining the new protocol should provide guidance for when
additional connections and/or sessions should be opened, as opposed
to reusing existing ones.
3.15. Extensibility
The protocol will provide a mechanism by which clients and servers
can add extension information to the exchange that establishes the IP
session. If the solution uses an HTTP request and response, this
could be accomplished using HTTP headers.
Once the session is established, the protocol will provide a
mechanism that allows reliably exchanging vendor-specific messages in
both directions at any point in the lifetime of the IP Session.
4. Non-requirements
This section discusses topics that are explicitly out of scope for
the IP Proxying protocol. These topics MAY be handled by
implementers or future extensions.
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4.1. Addressing Architecture
This document only describes the requirements for a protocol that
allows IP proxying. It does not discuss how the IPs assigned are
determined, managed, or translated. While these details are
important for producing a functional system, they do not need to be
handled by the protocol beyond the ability to convey those
assignments.
4.2. Translation
Some servers may wish to perform Network Address Translation (NAT) or
any other modification to packets they forward. Doing so is out of
scope for the proxying protocol. In particular, the ability to
discover the presence of a NAT, negotiate NAT bindings, or check
connectivity through a NAT is explicitly out of scope and left to
future extensions.
Servers that do not perform NAT will commonly forward packets
similarly to how a traditionnal IP router would, but the specific of
that are considered out of scope. In particular, decrementing the
Hop Limit (or TTL) field of the IP header is out of scope for MASQUE
and expected to be performed by a router behind the MASQUE server, or
collocated with it.
4.3. IP Packet Extraction
How packets are forwarded between the IP proxying connection and the
physical network is out of scope. This is deliberately not specified
and will be left to individual implementations.
5. Security Considerations
This document only discusses requirements on a protocol that allows
IP proxying. That protocol will need to document its security
considerations.
6. IANA Considerations
This document requests no actions from IANA.
Acknowledgments
The authors would like to thank participants of the MASQUE working
group for their feedback.
References
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Normative References
[DGRAM] Pauly, T., Kinnear, E., and D. Schinazi, "An Unreliable
Datagram Extension to QUIC", Work in Progress, Internet-
Draft, draft-ietf-quic-datagram-00, 26 February 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
datagram-00.txt>.
[H2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
DOI 10.17487/RFC7540, May 2015,
<https://www.rfc-editor.org/info/rfc7540>.
[H3] Bishop, M., "Hypertext Transfer Protocol Version 3
(HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
quic-http-29, 9 June 2020, <http://www.ietf.org/internet-
drafts/draft-ietf-quic-http-29.txt>.
[IPV4] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
[IPV6] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[QUIC] Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
and Secure Transport", Work in Progress, Internet-Draft,
draft-ietf-quic-transport-29, 9 June 2020,
<http://www.ietf.org/internet-drafts/draft-ietf-quic-
transport-29.txt>.
[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>.
[TLS] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
Informative References
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[CONNECT-UDP]
Schinazi, D., "The CONNECT-UDP HTTP Method", Work in
Progress, Internet-Draft, draft-schinazi-masque-connect-
udp-00, 16 April 2020, <http://www.ietf.org/internet-
drafts/draft-schinazi-masque-connect-udp-00.txt>.
[IKEV2] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[OAUTH] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/info/rfc6749>.
Authors' Addresses
Alex Chernyakhovsky
Google LLC
1600 Amphitheatre Parkway
Mountain View, California 94043,
United States of America
Email: achernya@google.com
Dallas McCall
Google LLC
1600 Amphitheatre Parkway
Mountain View, California 94043,
United States of America
Email: dallasmccall@google.com
David Schinazi
Google LLC
1600 Amphitheatre Parkway
Mountain View, California 94043,
United States of America
Email: dschinazi.ietf@gmail.com
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