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Versions: 00 01

QUIC Working Group                                             M. Piraux
Internet-Draft                                            O. Bonaventure
Intended status: Experimental                                  UCLouvain
Expires: January 14, 2021                                  July 13, 2020


                       Tunneling TCP inside QUIC
                    draft-piraux-quic-tunnel-tcp-01

Abstract

   This document specifies a new operating mode for a QUIC tunnel to
   efficiently convey TCP bytestreams.

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 https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   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 January 14, 2021.

Copyright Notice

   Copyright (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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.






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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  The stream mode . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Connection establishment  . . . . . . . . . . . . . . . . . .   4
   5.  Messages format . . . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  QUIC tunnel stream TLVs . . . . . . . . . . . . . . . . .   5
       5.1.1.  TCP Connect TLV . . . . . . . . . . . . . . . . . . .   6
       5.1.2.  TCP Connect OK TLV  . . . . . . . . . . . . . . . . .   6
       5.1.3.  Error TLV . . . . . . . . . . . . . . . . . . . . . .   6
       5.1.4.  End TLV . . . . . . . . . . . . . . . . . . . . . . .   8
   6.  Example flows . . . . . . . . . . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
     7.1.  Denial of Service . . . . . . . . . . . . . . . . . . . .   9
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Registration of QUIC tunnel Identification String . . . .   9
     8.2.  QUIC tunnel stream TLVs . . . . . . . . . . . . . . . . .   9
       8.2.1.  QUIC tunnel stream TLVs Types . . . . . . . . . . . .   9
       8.2.2.  QUIC tunnel streams TLVs Error Types  . . . . . . . .  10
     8.3.  QUIC Transport Parameter Registry . . . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  12
     A.1.  Since draft-piraux-quic-tunnel-tcp-00 . . . . . . . . . .  12
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  12

1.  Introduction

   The recently proposed QUIC tunnel protocol [I-D.piraux-quic-tunnel]
   supports the exchange of IP packets or Ethernet frames over a QUIC
   connection.  Its first operating mode, the datagram mode, transports
   plain packets inside QUIC frames.  Its main advantage is that it
   supports any network-layer protocol.  However, this advantage comes
   with a large per-packet overhead since each packet contains both a
   network and a transport header.  All these headers must be
   transmitted in addition to the IP/UDP/QUIC headers of the QUIC
   connection.  For TCP connections for instance, the per-packet
   overhead can be large.

   In this document, we propose a new operating mode for the QUIC tunnel
   protocol, called the stream mode.  It takes advantage of the QUIC
   streams to efficiently transport TCP bytestreams over a QUIC
   connection.  Section 3 describes this new mode.  Section 5 specifies
   the format of the messages introduced by this document.  Section 6
   contains example flows.



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2.  Conventions and Definitions

   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.

3.  The stream mode

   Since QUIC supports multiple streams, another possibility to carry
   the data exchanged over TCP connections between the client and the
   concentrator is to transport the bytestream of each TCP connection as
   one of the bidirectional streams of the QUIC connection.  For this,
   we base our approach on the 0-RTT Convert protocol
   [I-D.ietf-tcpm-converters] that was proposed to ease the deployment
   of TCP extensions.  In a nutshell, it is an application proxy that
   converts TCP connections, allowing the use of new TCP extensions
   through an intermediate relay.

   We use a similar approach in our stream mode.  When a client opens a
   stream, it sends at the beginning of the bytestream one or more TLV
   messages indicating the IP address and port number of the remote
   destination of the bytestream.  Their format is detailed in section
   Section 5.1.  Upon reception of such a TLV message, the concentrator
   opens a TCP connection towards the specified destination and connects
   the incoming bytestream of the QUIC connection to the bytestream of
   the new TCP connection (and similarly in the opposite direction).

   Figure 1 summarizes how the new TCP connection is mapped to the QUIC
   stream.  Actions and events of a TCP connection are translated to
   actions and events of the associated QUIC stream, so that a state
   transition on one is translated to the other.


















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   +------------------+-------------------------+
   |        TCP       |      QUIC Stream        |
   +------------------+-------------------------+
   | SYN received     | Open Stream, send TLVs  |
   | FIN received     | Send Stream FIN         |
   | RST received     | Send STOP_SENDING       |
   |                  | Send RESET_STREAM       |
   | Data received    | Send Stream data        |
   +------------------+-------------------------+

   +-------------------------------+------------+
   |         QUIC Stream           |    TCP     |
   +-------------------------------+------------+
   | Stream opened, TLVs received  | Send SYN   |
   | Stream FIN received           | Send FIN   |
   | STOP_SENDING received         | Send RST   |
   | RESET_STREAM received         | Send RST   |
   | Stream data received          | Send data  |
   +-------------------------------+------------+

              Figure 1: TCP connection to QUIC stream mapping

   When sending STOP_SENDING or RESET_STREAM frames in response to the
   receipt of a TCP RST, QUIC tunnel peers MUST use the application
   protocol error code 0x00 (TCP_CONNECTION_RESET).

   The QUIC stream-level flow control can be tuned to match the receive
   window size of the corresponding TCP connection, so that no excessive
   data needs to be buffered.

4.  Connection establishment

   The connection establishment follows the requirements described in
   Section 5 of [I-D.piraux-quic-tunnel].

   In addition, the support of the stream mode is negotiated during the
   connection establishment by including the quic_tunnel_stream_mode
   transport parameter (value TBD).  The parameter value has no meaning
   and SHOULD be null.

   During the connection establishment, the concentrator can control the
   number of TCP bytestreams that can be opened initially by setting the
   initial_max_streams_bidi QUIC transport parameter as defined in
   [I-D.ietf-quic-transport].







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5.  Messages format

   In the following sections, we specify the format of each message
   introduced in this document.  They are encoded using the TLV format
   described in [I-D.piraux-quic-tunnel].

5.1.  QUIC tunnel stream TLVs

   When using the stream mode, one or more messages are used to trigger
   and confirm the establishment of a connection towards the final
   destination for a given stream.  Those messages are exchanged on this
   QUIC stream before the TCP connection bytestream.  This section
   describes the format of these messages.

   This document specifies the following QUIC tunnel stream TLVs:

   +------+----------+-----------------------------+
   | Type |     Size | Name                        |
   +------+----------+-----------------------------+
   | 0x00 | 20 bytes | TCP Connect TLV             |
   | 0x01 |  2 bytes | TCP Connect OK TLV          |
   | 0x02 | Variable | Error TLV                   |
   | 0xff |  2 bytes | End TLV                     |
   +------+----------+-----------------------------+

                     Figure 2: QUIC tunnel stream TLVs

   The TCP Connect TLV is used to request the establishment a TCP
   connection by the concentrator towards the final destination.  The
   TCP Connect OK TLV confirms the establishment of this TCP connection.
   The Error TLV is used to indicate any error that occurred during the
   establishment of a TCP connection.  Finally, the End TLV marks the
   end of the series of TLVs and the start of the bytestream on a given
   QUIC stream.  These TLVs are detailed in the following sections.

   Future versions of this document may define new TLVs.  The End TLV
   allows a QUIC tunnel peer to send several TLVs before the start of
   the bytestream.

         Offset 0         Offset 20   Offset 22
            |                 |         |
   Client   v                 v         v
            +-----------------+---------+----------------
   Stream 0 | TCP Connect TLV | End TLV | TCP bytestream ...
            +-----------------+---------+----------------

            Figure 3: Example of use of QUIC tunnel stream TLVs




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   Figure 3 illustrates an example of use of QUIC tunnel streams TLVs.
   In this example, the client opens Stream 0 and sends two TLVs.  The
   first one requests the concentrator to establish a new TCP
   connection.  The second TLV marks the end of the series of TLV and
   the start of the TCP bytestream.

5.1.1.  TCP Connect TLV

   The TCP Connect TLV indicates the final destination of the TCP
   connection associated to a given QUIC stream.  The fields Remote Peer
   Port and Remote Peer IP Address contain the destination port number
   and IP address of the final destination.

   The Remote Peer IP Address MUST be encoded as an IPv6 address.  IPv4
   addresses MUST be encoded using the IPv4-Mapped IPv6 Address format
   defined in [RFC4291].  Further, the Remote Peer IP address field MUST
   NOT include multicast, broadcast, and host loopback addresses
   [RFC6890].

   A QUIC tunnel peer MUST NOT send more than one TCP Connect TLV per
   QUIC stream.  A QUIC tunnel peer MUST NOT send a TCP Connect TLV on
   non-self initiated streams.

                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Type (8)   |   Length (8)  |     Remote Peer Port (16)     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                  Remote Peer IP Address (128)                 |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                         Figure 4: TCP Connect TLV

5.1.2.  TCP Connect OK TLV

   The TCP Connect OK TLV does not contain a value.  Its presence
   confirms the successful establishment of the requested TCP connection
   to the final destination.  A QUIC peer MUST NOT send a TCP Connect OK
   TLV on self-initiated streams.

5.1.3.  Error TLV

   The Error TLV indicates out-of-band errors that occurred during the
   establishment of the TCP connection to the final destination.  These
   errors can be ICMP Destination Unreachable messages for instance.  In



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   this case the ICMP packet received by the concentrator is copied
   inside the Error Payload field.

                        1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Type (8)   |   Length (8)  |        Error Code (16)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     [Error Payload (*)]                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                            Figure 5: Error TLV

   The following bytestream-level error codes are defined in this
   document:

   +------+---------------------------+
   | Code | Name                      |
   +------+---------------------------+
   |  0x0 | Protocol Violation        |
   |  0x1 | ICMP Packet Received      |
   |  0x2 | Malformed TLV             |
   |  0x3 | Network Failure           |
   +------+---------------------------+

                  Figure 6: Bytestream-level Error Codes

   o  Protocol Violation (0x0): A general error code for all non-
      conforming behaviors encountered.  A QUIC tunnel peer SHOULD use a
      more specific error code when possible.

   o  ICMP Packet Received (0x1): This code indicates that the
      concentrator received an ICMP packet while trying to create the
      associated TCP connection.  The Error Payload contains the packet.

   o  Malformed TLV (0x2): This code indicates that a received TLV was
      not successfully parsed or formed.  A peer receiving a TCP Connect
      TLV with an invalid IP address MUST send an Error TLV with this
      error code.

   o  Network Failure (0x3): This codes indicates that a network failure
      prevented the establishment of the connection.

   After sending one or more Error TLVs, the sender MUST send an End TLV
   and terminate the stream, i.e. set the FIN bit after the End TLV.






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5.1.4.  End TLV

   The End TLV does not contain a value.  Its existence signals the end
   of the series of TLVs.  The next byte in the QUIC stream after this
   TLV is part of of the tunneled bytestream.

6.  Example flows

   This section illustrates the different messages described previously
   and how they are used in a QUIC tunnel connection.  For QUIC STREAM
   frames, we use the following syntax: STREAM[ID, Stream Data [, FIN]].
   The first element is the Stream ID, the second is the Stream Data
   contained in the frame and the last one is optional and indicates
   that the FIN bit is set.

   Client                      Concentrator           Final Destination
    | STREAM[0, "TCP Connect, End"] ||                               |
    |------------------------------>||              SYN              |
    |                               ||==============================>|
    |                               ||            SYN+ACK            |
    |STREAM[0,"TCP Connect OK, End"]||<==============================|
    |<------------------------------||                               |
    | STREAM[0, "bytestream data"]  ||                               |
    |------------------------------>||     bytestream data, ACK      |
    |                               ||==============================>|
    |                               ||     bytestream data, ACK      |
    |  STREAM[0, "bytestream data"] ||<==============================|
    |<------------------------------||              FIN              |
    |      STREAM[0, "", FIN]       ||<==============================|
    |<------------------------------||              ACK              |
    |      STREAM[0, "", FIN]       ||==============================>|
    |------------------------------>||              FIN              |
    |                               ||==============================>|
    |                               ||              ACK              |
    |                               ||<==============================|

   Legend:
      --- QUIC connection
      === TCP connection

                Figure 7: Example flow for the stream mode

   On Figure 7, the client is initiating a TCP connection in stream mode
   to the Final Destination.  A request and a response are exchanged,
   then the connection is torn down gracefully.  A remote-initiated
   connection accepted by the concentrator on behalf of the client would
   have the order and the direction of all messages reversed.




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7.  Security Considerations

7.1.  Denial of Service

   There is a risk of an amplification attack when the Concentrator
   sends a TCP SYN in response of a TCP Connect TLV.  When a TCP SYN is
   larger than the client request, the Concentrator amplifies the client
   traffic.  To mitigate such attacks, the Concentrator SHOULD rate
   limit the number of pending TCP Connect from a given client.

8.  IANA Considerations

8.1.  Registration of QUIC tunnel Identification String

   This document creates a new registration for the identification of
   the QUIC tunnel protocol in the "Application Layer Protocol
   Negotiation (ALPN) Protocol IDs" registry established in [RFC7301].

   The "qt" string identifies the QUIC tunnel protocol.

   Protocol: QUIC tunnel

   Identification Sequence: 0x71 0x74 ("qt")

   Specification: This document

8.2.  QUIC tunnel stream TLVs

   IANA is requested to create a new "QUIC tunnel stream Parameters"
   registry.

   The following subsections detail new registries within "QUIC tunnel
   stream Parameters" registry.

8.2.1.  QUIC tunnel stream TLVs Types

   IANA is request to create the "QUIC tunnel stream TLVs Types" sub-
   registry.  New values are assigned via IETF Review (Section 4.8 of
   [RFC8126]).

   The initial values to be assigned at the creation of the registry are
   as follows:









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   +------+-----------------------------+------------+
   | Code | Name                        | Reference  |
   +------+-----------------------------+------------+
   |    0 | TCP Connect TLV             | [This-Doc] |
   |    1 | TCP Connect OK TLV          | [This-Doc] |
   |    2 | Error TLV                   | [This-Doc] |
   |  255 | End TLV                     | [This-Doc] |
   +------+-----------------------------+------------+

8.2.2.  QUIC tunnel streams TLVs Error Types

   IANA is request to create the "QUIC tunnel stream TLVs Error Types"
   sub-registry.  New values are assigned via IETF Review (Section 4.8
   of [RFC8126]).

   The initial values to be assigned at the creation of the registry are
   as follows:

   +------+---------------------------+------------+
   | Code | Name                      | Reference  |
   +------+---------------------------+------------+
   |    0 | Protocol Violation        | [This-Doc] |
   |    1 | ICMP packet received      | [This-Doc] |
   |    2 | Malformed TLV             | [This-Doc] |
   |    3 | Network Failure           | [This-Doc] |
   +------+---------------------------+------------+

8.3.  QUIC Transport Parameter Registry

   This document defines a new transport parameter for the negotiation
   of the stream mode.  The following entry in Table 1 should be added
   to the "QUIC Transport Parameters" registry under the "QUIC Protocol"
   heading.

            +-------+-------------------------+---------------+
            | Value | Parameter Name          | Specification |
            +-------+-------------------------+---------------+
            | TBD   | quic_tunnel_stream_mode | Section 4     |
            +-------+-------------------------+---------------+

          Table 1: Addition to QUIC Transport Parameters Entries

9.  References








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9.1.  Normative References

   [I-D.piraux-quic-tunnel]
              Piraux, M. and O. Bonaventure, "Tunneling Internet
              protocols inside QUIC", draft-piraux-quic-tunnel-01 (work
              in progress), March 2020.

   [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>.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, DOI 10.17487/RFC4291, February
              2006, <https://www.rfc-editor.org/info/rfc4291>.

   [RFC6890]  Cotton, M., Vegoda, L., Bonica, R., Ed., and B. Haberman,
              "Special-Purpose IP Address Registries", BCP 153,
              RFC 6890, DOI 10.17487/RFC6890, April 2013,
              <https://www.rfc-editor.org/info/rfc6890>.

   [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>.

9.2.  Informative References

   [I-D.ietf-quic-transport]
              Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed
              and Secure Transport", draft-ietf-quic-transport-29 (work
              in progress), June 2020.

   [I-D.ietf-tcpm-converters]
              Bonaventure, O., Boucadair, M., Gundavelli, S., Seo, S.,
              and B. Hesmans, "0-RTT TCP Convert Protocol", draft-ietf-
              tcpm-converters-19 (work in progress), March 2020.

   [RFC7301]  Friedl, S., Popov, A., Langley, A., and E. Stephan,
              "Transport Layer Security (TLS) Application-Layer Protocol
              Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
              July 2014, <https://www.rfc-editor.org/info/rfc7301>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.





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Appendix A.  Change Log

A.1.  Since draft-piraux-quic-tunnel-tcp-00

   o  Adds the quic_tunnel_stream_mode transport parameter for
      negotiation

Acknowledgments

   This documents draws heavily on the initial version of
   [I-D.piraux-quic-tunnel].  Their contributors are thanked again here.
   This work was partially supported by the MQUIC project.

Authors' Addresses

   Maxime Piraux
   UCLouvain

   Email: maxime.piraux@uclouvain.be


   Olivier Bonaventure
   UCLouvain

   Email: olivier.bonaventure@uclouvain.be


























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