Requirements for a MASQUE Protocol to Proxy IP Traffic
draft-cms-masque-ip-proxy-reqs-01

Versions: 00 01                                                         
Network Working Group                                  A. Chernyakhovsky
Internet-Draft                                                 D. McCall
Intended status: Informational                               D. Schinazi
Expires: 14 January 2021                                      Google LLC
                                                            13 July 2020


         Requirements for a MASQUE Protocol to Proxy IP Traffic
                   draft-cms-masque-ip-proxy-reqs-00

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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   This Internet-Draft will expire on 14 January 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.










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   This document is subject to BCP 78 and the IETF Trust's Legal
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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.  Point to Point Connectivity . . . . . . . . . . . . . . .   4
     2.2.  Point to Network Connectivity . . . . . . . . . . . . . .   4
     2.3.  Network to Network Connectivity . . . . . . . . . . . . .   4
   3.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  IP Session Establishment  . . . . . . . . . . . . . . . .   4
     3.2.  Proxying of IP packets  . . . . . . . . . . . . . . . . .   4
     3.3.  Maximum Transmission Unit . . . . . . . . . . . . . . . .   5
     3.4.  IP Assignment . . . . . . . . . . . . . . . . . . . . . .   5
     3.5.  Route Negotiation . . . . . . . . . . . . . . . . . . . .   5
     3.6.  Identity  . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.7.  Transport Security  . . . . . . . . . . . . . . . . . . .   5
     3.8.  Authentication  . . . . . . . . . . . . . . . . . . . . .   5
     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 . . . . . . . . . . . . . . . .   6
     3.13. Multiplexing  . . . . . . . . . . . . . . . . . . . . . .   6
     3.14. Load balancing  . . . . . . . . . . . . . . . . . . . . .   6
     3.15. Extensibility . . . . . . . . . . . . . . . . . . . . . .   7
   4.  Non-requirements  . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Addressing Architecture . . . . . . . . . . . . . . . . .   7
     4.2.  Translation . . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  IP Packet Extraction  . . . . . . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   8
   References  . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     Normative References  . . . . . . . . . . . . . . . . . . . . .   8
     Informative References  . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9






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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.  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.

2.2.  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.

2.3.  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.

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].








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3.3.  Maximum Transmission Unit

   The protocol will allow endpoints to negotiate the Maximum
   Transmission Unit (MTU) in use over a given Data Transport.  This
   will allow avoiding IP fragmentation, especially as IPv6 does not
   allow IP fragmentation by nodes along the path.

3.4.  IP Assignment

   Both the client or server may request to be assigned an IP address
   range.  In response to the request, the peer will respond with an IP
   address range of its choosing.

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
   request routes to specific IP address ranges.  In response to this
   request, the peer will have the ability to respond with a subset of
   routes that it is willing to accept, or deny the request.

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.

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.








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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.

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.








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   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.

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.

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.





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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

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>.








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   [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

   [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






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   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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