AVTCORE Working Group B. Aboba
INTERNET-DRAFT Microsoft Corporation
Category: Informational P. Thatcher
Expires: July 28, 2020 Google
C. Perkins
University of Glasgow
28 January 2020
QUIC Multiplexing draft-aboba-avtcore-quic-multiplexing-04.txtAbstract
If QUIC is to be used for peer-to-peer data transport with NAT traversal, then it is necessary to be able to demultiplex QUIC and other protocols used in WebRTC on a single UDP port. This memo discusses a proposed scheme for demultiplexing.
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 working documents as Internet-Drafts. The list of current Internet- 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."
This Internet-Draft will expire on 28 July 2020.
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Copyright NoticeCopyright (c) 2020 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 Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Security Considerations . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Informative references . . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
QUIC [I-D.ietf-quic-transport] is a new network transport protocol. While it is initially intended as a replacement for TCP in order to better support HTTP/2 [RFC7540], with the introduction of datagram support [I-D.pauly-quic-datagram] it will also support unreliable as well as reliable transport. HTTP is an asymmetric client-server protocol, but other uses of QUIC support peer-to-peer operation and so will need effective NAT traversal using ICE [RFC5245], which which makes use of STUN [RFC5389] and TURN [RFC5766] to discover NAT bindings. Therefore for QUIC to be utilized for peer-to-peer data transport, QUIC and STUN must be able to multiplex on the same port.In a WebRTC scenario where RTP is used to transport audio and video and QUIC is used for data exchange, SRTP [RFC3711] is keyed using DTLS-SRTP [RFC5764] and therefore SRTP/SRTCP [RFC3550], STUN, TURN, DTLS [RFC6347] and QUIC will need to be multiplexed on the same port.
Within the W3C, a Javascript API for the use of QUIC for peer-to-peer data exchange [WEBRTC-QUIC] is under development within the ORTC Community Group, and an Origin Trial [WEBRTC-QUIC-TRIAL] implementing an early version of this API shipped in the Chrome and Edge browsers. Due to lack of demultiplexing support, the Origin Trial could only support peer-to-peer use of QUIC over a standalone ICE transport, as defined in [WEBRTC-ICE].
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As noted in [RFC7983] Figure 3, protocol demultiplexing currently relies upon differentiation based on the first octet, as follows:
+----------------+
| [0..3] -+--> forward to STUN
| |
| [16..19] -+--> forward to ZRTP
| |
packet --> | [20..63] -+--> forward to DTLS
| |
| [64..79] -+--> forward to TURN Channel
| |
| [128..191] -+--> forward to RTP/RTCP
+----------------+
Figure 1: RFC 7983 packet demultiplexing algorithm.As noted by Colin Perkins and Lars Eggert in [QUIC-Issue][QUIC-MULTI] this created a potential conflict with the design of the QUIC headers described in versions of [I-D.ietf-quic-transport] prior to -08.
1.1. Terminology
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 [RFC2119].
2. Solution
As of draft 18, the QUIC Long Header packet type field defined in [I- D.ietf-quic-transport] Section 17.2 appears as follows:
+-+-+-+-+-+-+-+-+
|1|1|T T|X|X|X|X|
+-+-+-+-+-+-+-+-+
Where:T = Long Packet Type (0x0 - 0x3) X = Type-Specific Bits.
This potentially produces values of the first octet in the ranges 192-255. The QUIC Short Header packet type field defined in [I-D.ietf-quic- transport] Section 17.3 appears as follows:
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+-+-+-+-+-+-+-+-+
|0|1|S|R|R|K|P P|
+-+-+-+-+-+-+-+-+
Where:S = Spin Bit R = Reserved bits K = Key Phase bit P = Packet Number Length.
This potentially produces values of the first octet in the ranges 64-127 (assuming that the reserved bits may not always be set to zero).
As a result, the multiplexing scheme supported in -18 operates as follows:
+----------------+
| [0..3] -+--> forward to STUN
| |
| [16..19] -+--> forward to ZRTP
| |
packet --> | [20..63] -+--> forward to DTLS
| |
| [64..79] -+--> forward to TURN Channel
| [64..127] -+--> forward to QUIC (Short Header)
| |
| [128..191] -+--> forward to RTP/RTCP
| [192..255] +--> forward to QUIC (Long Header)
+----------------+
Figure 3: Packet demultiplexing algorithm in Draft 18.Note that while the above diagram has a potential conflict between packets sent in TURN Channels and the QUIC short header, this conflict is not considered serious for WebRTC where TURN Channels are rarely used.
3. Security Considerations
The solution discussed in this document could potentially introduce some additional security considerations beyond those detailed in [RFC7983]. Due to the additional logic required, if mis-implemented, heuristics have the potential to mis-classify packets.
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When QUIC is used for only for data exchange, the TLS-within-QUIC exchange [I-D.ietf-quic-tls] derives keys used solely to protect the QUIC data packets. If properly implemented, this should not affect the transport of SRTP nor the derivation of SRTP keys via DTLS-SRTP, but if badly implemented, both transport and key derivation could be adversely impacted.
4. IANA Considerations
This document does not require actions by IANA.5. References 5.1. Informative References[I-D.ietf-quic-tls]
Thomson, M. and S. Turner, "Using Transport Layer Security (TLS) to Secure QUIC", draft-ietf-quic-tls-25 (work in progress), January 22, 2020.
[I-D.ietf-quic-transport]
Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed and Secure Transport", draft-ietf-quic-transport-25 (work in progress), January 22, 2020.
[I-D.pauly-quic-datagram]
Pauly, T., Kinnear, E. and D. Schinazi, "An Unreliable Datagram Extension to QUIC", draft-pauly-quic-datagram-05 (work in progress), November 04, 2019.
[QUIC-Issue] Perkins, C., "QUIC header format/demultiplexing",
https://github.com/quicwg/base-drafts/issues/426, March, 2017.
[QUIC-MULTI] Perkins, C., "QUIC Multiplexing and Peer-to-Peer",
presentation to IETF AVTCORE WG at IETF 100, <https://datatracker.ietf.org/meeting/100/materials/ slides-100-avtcore-quic-multiplexing-with-rtp-03>, November 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc- editor.org/info/rfc2119>.
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[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V.Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, July 2003, <http://www.rfc-editor.org/info/rfc3550>.
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, DOI 10.17487/RFC3711, March 2004, <http://www.rfc-editor.org/info/rfc3711>.
[RFC5245] Rosenberg, J., "Interactive Connectivity Establishment
(ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols", RFC 5245, DOI 10.17487/RFC5245, April 2010, <http://www.rfc- editor.org/info/rfc5245>.
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389, DOI 10.17487/RFC5389, October 2008, <http://www.rfc- editor.org/info/rfc5389>.
[RFC5764] McGrew, D. and E. Rescorla, "Datagram Transport Layer
Security (DTLS) Extension to Establish Keys for the Secure Real-time Transport Protocol (SRTP)", RFC 5764, DOI 10.17487/RFC5764, May 2010, <http://www.rfc- editor.org/info/rfc5764>.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session Traversal Utilities for NAT (STUN)", RFC 5766, DOI 10.17487/RFC5766, April 2010, <http://www.rfc- editor.org/info/rfc5766>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347, January 2012, <http://www.rfc-editor.org/info/rfc6347>.
[RFC7540] 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>.
[RFC7983] Petit-Huguenin, M. and G. Salgueiro, "Multiplexing Scheme
Updates for Secure Real-time Transport Protocol (SRTP) Extension for Datagram Transport Layer Security (DTLS)", RFC 7983, DOI 10.17487/RFC7983, September 2016, <https://www.rfc-editor.org/info/rfc7983>.
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[WEBRTC-ICE] Thatcher, P. and B. Aboba, "ICE Transport Extensions forWebRTC", W3C Editor's Draft (work in progress), January 2020, <https://w3c.github.io/webrtc-ice>
[WEBRTC-QUIC]
Thatcher, P. and B. Aboba, "QUIC API For Peer-to-Peer Connections", W3C Community Group Draft (work in progress), January 2020, <https://w3c.github.io/webrtc-quic>
[WEBRTC-QUIC-TRIAL]
Hampson, S., "RTCQuicTransport Coming to an Origin Trial Near You (Chrome 73)", January 2019, <https://developers.google.com/web/updates/ 2019/01/rtcquictransport-api>
Acknowledgments
We would like to thank Martin Thomson, Roni Even and other participants in the IETF QUIC and AVTCORE working groups for their discussion of the QUIC multiplexing issue, and their input relating to potential solutions.
Authors' Addresses
Bernard Aboba Microsoft Corporation One Microsoft Way Redmond, WA 98052 USA
Email: bernard.aboba@gmail.com
Peter Thatcher Google 747 6th St S Kirkland, WA 98033 USA
Email: pthatcher@google.com
Colin Perkins School of Computing Science University of Glasgow Glasgow G12 8QQ United Kingdom
Email: csp@csperkins.org
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