Multiplexing Scheme Updates for QUIC
draft-ietf-avtcore-rfc7983bis-04

AVTCORE Working Group                                           B. Aboba
INTERNET-DRAFT                                     Microsoft Corporation
Updates: 7983, 5764                                         G. Salgueiro
Category: Standards Track                                  Cisco Systems
Expires: November 13, 2022                                    C. Perkins
                                                   University of Glasgow
                                                             12 May 2022

                  Multiplexing Scheme Updates for QUIC
                  draft-ietf-avtcore-rfc7983bis-04.txt

Abstract

   This document defines how QUIC, Datagram Transport Layer Security
   (DTLS), Real-time Transport Protocol (RTP), RTP Control Protocol
   (RTCP), Session Traversal Utilities for NAT (STUN), Traversal Using
   Relays around NAT (TURN), and ZRTP packets are multiplexed on a
   single receiving socket.

   This document updates RFC 7983 and RFC 5764.

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 November 13, 2022.

Aboba, et. al                Standards Track                    [Page 1]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

Copyright Notice

   Copyright (c) 2022 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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Multiplexing of TURN Channels . . . . . . . . . . . . . . . .   3
   3.  Updates to RFC 7983 . . . . . . . . . . . . . . . . . . . . .   4
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6. References . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

Aboba, et. al                Standards Track                    [Page 2]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

1.  Introduction

   "Multiplexing Scheme Updates for Secure Real-time Transport Protocol
   (SRTP) Extension for Datagram Transport Layer Security (DTLS)"
   [RFC7983] defines a scheme for a Real-time Transport Protocol (RTP)
   [RFC3550] receiver to demultiplex DTLS [RFC9147], Session Traversal
   Utilities for NAT (STUN) [RFC8489], Secure Real-time Transport
   Protocol (SRTP) / Secure Real-time Transport Control Protocol (SRTCP)
   [RFC3711], ZRTP [RFC6189] and TURN Channel packets arriving on a
   single port.  This document updates [RFC7983] and [RFC5764] to also
   allow QUIC [RFC9000] to also be multiplexed on the same port.

   The multiplexing scheme described in this document enables multiple
   usage scenarios. Peer-to-peer QUIC in WebRTC scenarios, described in
   [P2P-QUIC] [P2P-QUIC-TRIAL], uses RTP for transport of audio and
   video along with QUIC for data exchange.  For this use case, SRTP
   [RFC3711] is keyed using DTLS-SRTP [RFC5764] and therefore SRTP/SRTCP
   [RFC3550], STUN, TURN, DTLS and QUIC need to be multiplexed on the
   same port. Were SRTP to be keyed using QUIC-SRTP, SRTP/SRTCP, STUN,
   TURN and QUIC would need to be multiplexed on the same port.  Where
   QUIC is used for peer-to-peer transport of data as well as RTP
   [I-D.engelbart-rtp-over-quic] STUN, TURN and QUIC need to be
   multiplexed on the same port.

   The scheme described in this document is compatible with QUIC version
   2 [I-D.ietf-quic-v2]. However, it is not compatible with QUIC Bit
   greasing, as defined in [I-D.ietf-quic-bit-grease].  Therefore, in
   situations where multiplexing is desired, QUIC Bit greasing MUST NOT
   be negotiated.

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.  Multiplexing of TURN Channels

   TURN channels are an optimization where data packets are exchanged
   with a 4-byte prefix instead of the standard 36-byte STUN overhead
   (see Section 3.5 of [RFC8656]).  [RFC7983] allocated the values from
   64 to 79 in order to allow TURN channels to be demultiplexed when the
   TURN Client does the channel binding request in combination with the
   demultiplexing scheme described in [RFC7983].

   When QUIC Bit greasing is not negotiated, the first octet of a QUIC
   short header packet falls in the range 64 to 127, thereby overlapping
   with the allocated range for TURN channels of 64 to 79.

Aboba, et. al                Standards Track                    [Page 3]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

   Where QUIC Bit greating is not negotiated, the first octet of QUIC
   long header packets fall in the range 192 to 255.  Since QUIC long
   header packets preceed QUIC short header packets, if no packets with
   a first octet in the range of 192 to 255 have been received, a packet
   whose first octet is in the range of 64 to 79 can be demultplexed
   unambiguously as TURN Channel traffic.  Since WebRTC implementations
   supporting QUIC data exchange do not utilize TURN Channels, once
   packets with a first octet in the range of 192 to 255 have been
   received, a packet whose first octet is in the range of 64 to 127 can
   be demultiplexed as QUIC traffic.

3.  Updates to RFC 7983

   This document updates the text in Section 7 of [RFC7983] (which in
   turn updates [RFC5764]) as follows:

   OLD TEXT

   The process for demultiplexing a packet is as follows.  The receiver
   looks at the first byte of the packet.  If the value of this byte is
   in between 0 and 3 (inclusive), then the packet is STUN.  If the
   value is between 16 and 19 (inclusive), then the packet is ZRTP.  If
   the value is between 20 and 63 (inclusive), then the packet is DTLS.
   If the value is between 64 and 79 (inclusive), then the packet is
   TURN Channel.  If the value is in between 128 and 191 (inclusive),
   then the packet is RTP (or RTCP, if both RTCP and RTP are being
   multiplexed over the same destination port).  If the value does not
   match any known range, then the packet MUST be dropped and an alert
   MAY be logged.  This process is summarized in Figure 3.

                    +----------------+
                    |        [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 3: The DTLS-SRTP receiver's packet demultiplexing algorithm.

   END OLD TEXT

Aboba, et. al                Standards Track                    [Page 4]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

   NEW TEXT

   The process for demultiplexing a packet is as follows.  The receiver
   looks at the first byte of the packet.  If the value of this byte is
   in between 0 and 3 (inclusive), then the packet is STUN.  If the
   value is between 16 and 19 (inclusive), then the packet is ZRTP.  If
   the value is between 20 and 63 (inclusive), then the packet is DTLS.
   If the value is in between 128 and 191 (inclusive) then the packet is
   RTP (or RTCP, if both RTCP and RTP are being multiplexed over the
   same destination port). If the value is between 80 and 127 or between
   192 and 255 (inclusive) then the packet is QUIC. If the value is
   between 64 and 79 inclusive, then if a packet has been previously
   forwarded that is in the range of 192 and 255, then the packet is
   QUIC, otherwise it is TURN Channel.

   If the value does not match any known range, then the packet MUST be
   dropped and an alert MAY be logged. This process is summarized in
   Figure 3.

                       +----------------+
                       |        [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: The receiver's packet demultiplexing algorithm.

   Note: The demultiplexing of QUIC packets requires that QUIC Bit
   greasing [I-D.ietf-quic-bit-grease] not be negotiated.

   END NEW TEXT

4.  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.

Aboba, et. al                Standards Track                    [Page 5]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

   When QUIC is used only for data exchange, the TLS-within-QUIC
   exchange [RFC9001] 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.
   However, were the TLS-within-QUIC exchange to be used to derive SRTP
   keys, both transport and SRTP key derivation could be aversely
   impacted by a vulnerability in the QUIC implementation.

5.  IANA Considerations

   This document does not require actions by IANA.

6.  References

6.1.  Normative References

[I-D.ietf-quic-bit-grease]
             Thomson, M., "Greasing the QUIC Bit", draft-ietf-quic-bit-
             grease (work in progress), November 10, 2021.

[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>.

[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>.

[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>.

[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>.

Aboba, et. al                Standards Track                    [Page 6]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

[RFC8489]    Petit-Huguenin, M., Salgueiro, G., Rosenberg, J., Wing, D.,
             Mahy, R. and P. Matthews, "Session Traversal Utilities for
             NAT (STUN), RFC 8489, DOI 10.17487/RFC8489, February 2020,
             <https://www.rfc-editor.org/info/rfc8489>.

[RFC8656]    Reddy, T., Johnston, A., Matthews, P. and J. Rosenberg,
             "Traversal Using Relays around NAT (TURN): Relay Extensions
             to Session Traversal Utilities for NAT (STUN)", RFC 8656,
             DOI 10.17487/RFC8656, February 2020, <https://www.rfc-
             editor.org/info/rfc8656>.

[RFC9000]    Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
             Multiplexed and Secure Transport", RFC 9000, DOI
             10.17487/RFC9000, May 2021, <https://www.rfc-
             editor.org/info/rfc9000>.

[RFC9001]    Thomson, M., Ed. and S. Turner, Ed., "Using TLS to Secure
             QUIC", RFC 9001, DOI 10.17487/RFC9001, May 2021,
             <https://www.rfc-editor.org/info/rfc9001>.

[RFC9147]    Rescorla, E., Tschofenig, H., and N. Modadugu, "The
             Datagram Transport Layer Security (DTLS) Protocol Version
             1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
             <https://www.rfc-editor.org/info/rfc9147>.

6.2.  Informative References

[I-D.engelbart-rtp-over-quic]
             Ott, J. and M. Engelbart, "RTP over QUIC", draft-engelbart-
             rtp-over-quic-02 (work in progress), March 7, 2022.

[I-D.ietf-quic-v2]
             Duke, M., "QUIC Version 2", draft-ietf-quic-v2 (work in
             progress), April 28, 2022.

[RFC6189]    Zimmermann, P., Johnston, A., Ed., and J. Callas, "ZRTP:
             Media Path Key Agreement for Unicast Secure RTP", RFC 6189,
             DOI 10.17487/RFC6189, April 2011, <http://www.rfc-
             editor.org/info/rfc6189>.

[P2P-QUIC]   Thatcher, P., Aboba, B. and R. Raymond, "QUIC API For Peer-
             to-Peer Connections", W3C ORTC Community Group Draft (work
             in progress), 23 May 2021, <https://github.com/w3c/p2p-
             webtransport>

[P2P-QUIC-TRIAL]
             Hampson, S., "RTCQuicTransport Coming to an Origin Trial
             Near You (Chrome 73)", January 2019,

Aboba, et. al                Standards Track                    [Page 7]
INTERNET-DRAFT    Multiplexing Scheme Updates for QUIC       12 May 2022

             <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

   Gonzalo Salgueiro
   Cisco Systems
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   United States of America

   Email: gsalguei@cisco.com

   Colin Perkins
   School of Computing Science
   University of Glasgow
   Glasgow  G12 8QQ
   United Kingdom

   Email: csp@csperkins.org

Aboba, et. al                Standards Track                    [Page 8]