Zero Checksum for the Stream Control Transmission Protocol
draft-tuexen-tsvwg-sctp-zero-checksum-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Michael Tüxen , Victor Boivie , Florent Castelli , Randell Jesup | ||
| Last updated | 2022-10-24 | ||
| Replaced by | draft-ietf-tsvwg-sctp-zero-checksum | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-tuexen-tsvwg-sctp-zero-checksum-00
Network Working Group M. Tüxen
Internet-Draft Münster Univ. of Appl. Sciences
Intended status: Standards Track V. Boivie
Expires: 27 April 2023 F. Castelli
Google
R. Jesup
Mozilla
24 October 2022
Zero Checksum for the Stream Control Transmission Protocol
draft-tuexen-tsvwg-sctp-zero-checksum-00
Abstract
The Stream Control Transmission Protocol (SCTP) uses a 32-bit
checksum in the common header of each packet to provide some level of
data integrity. When the lower layer used by SCTP does already
provide the same or a higher level of data integrity, computing this
checksum does not provide any additional protection, but does require
computing resources. This document provides a simple extension to
SCTP allowing to save these computing resources by using the constant
0 as the checksum.
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
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 27 April 2023.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
Tüxen, et al. Expires 27 April 2023 [Page 1]
Internet-Draft Zero Checksum for SCTP October 2022
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. A New Chunk Parameter . . . . . . . . . . . . . . . . . . . . 3
4. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Socket API Considerations . . . . . . . . . . . . . . . . . . 4
5.1. Get or Set Accepting a Zero Checksum
(SCTP_ACCEPT_ZERO_CHECKSUM) . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
SCTP as specified in [RFC9260] uses a CRC32c to provide some level of
data integrity. When using, for example, Datagram Transport Layer
Security (DTLS) as the lower layer for SCTP as specified in
[RFC8261], using the CRC32c does not provide any additional
protection over the one already provided by DTLS. However, computing
the CRC32c at the sender and receiver side does require computational
resources for no benefit. This is in particular important for
computational limited end points using SCTP encapsulated in DTLS.
The extension described in this document allows an SCTP end point to
declare that it accepts SCTP packets with a checksum of zero. This
declaration happens during the setup of the SCTP association and
allows end points supporting this extension to be interoperable with
end points not supporting the extension described in this document.
End points using this extension still need to implement the CRC32c
checksum algorithms.
Tüxen, et al. Expires 27 April 2023 [Page 2]
Internet-Draft Zero Checksum for SCTP October 2022
2. 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.
3. A New Chunk Parameter
The Zero Checksum Acceptable Chunk Parameter is defined by the
following figure.
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 = 0x8001 | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Zero Checksum Acceptable Chunk Parameter
Type: 16 bits (unsigned integer)
This field holds the IANA defined parameter type for the "Zero
Checksum Acceptable" chunk parameter. IANA is requested to assign
the value 32769 (0x8001) for this parameter type.
Length: 16 bits (unsigned integer)
This field holds the length in bytes of the chunk parameter; the
value MUST be 4.
All transported integer numbers are in "network byte order" a.k.a.,
Big Endian.
The Zero Checksum Acceptable Chunk Parameter MAY appear in INIT and
INIT ACK chunks. It MUST NOT appear in any other chunk.
If an end point not supporting the extension described in this
document receives this parameter in an INIT or INIT ACK chunk, it
skips it and continues to process further parameters in the chunk.
This behaviour is REQUIRED by [RFC9260] because the highest-order 2
bits of the Type are 10.
4. Procedures
An end point willing to accept SCTP packets with a checksum of zero,
MAY include the Zero Checksum Acceptable Chunk Parameter in the INIT
or INIT ACK chunk it sends. An end point MUST do this consistently.
Tüxen, et al. Expires 27 April 2023 [Page 3]
Internet-Draft Zero Checksum for SCTP October 2022
If an end point has sent the Zero Checksum Acceptable Chunk Parameter
in an INIT or INIT ACK chunk, it MUST accept SCTP packets using a
checksum value of zero for this association. It MUST also accept
SCTP packets containing the correct CRC32c checksum field.
When an end point sends a packet containing an INIT chunk, it MUST
include a CRC32c checksum in the packet containing the INIT chunk.
When an end point receives an "Out of the Blue" (OOTB) SCTP packet
and needs to send a response, it MUST include a CRC32c checksum in
the response.
If an end point has received an INIT or INIT ACK chunk from its peer
during the association setup, it MAY use zero as the checksum for all
packets sent in this association.
5. Socket API Considerations
This section describes how the socket API defined in [RFC6458] needs
to be extended to provide a way for the application to control the
UDP encapsulation.
Please note that this section is informational only.
A socket API implementation based on [RFC6458] is extended by
supporting one new read/write IPPROTO_SCTP level socket option.
5.1. Get or Set Accepting a Zero Checksum (SCTP_ACCEPT_ZERO_CHECKSUM)
This socket option can be used to control the acceptance of a zero
checksum. It applies only to future SCTP associations on the socket.
This option expects an integer boolean flag, where a non-zero value
turns on the option, and a zero value turns off the option.
This option is off by default.
6. IANA Considerations
[NOTE to RFC-Editor: "RFCXXXX" is to be replaced by the RFC number
you assign this document.]
[NOTE to RFC-Editor: The requested value for the parameter type is
tentative and to be confirmed by IANA.]
This document (RFCXXXX) is the reference for the registration
described in this section.
Tüxen, et al. Expires 27 April 2023 [Page 4]
Internet-Draft Zero Checksum for SCTP October 2022
A new chunk parameter type has to be assigned by IANA. This requires
an additional line in the "Chunk Parameter Types" registry for SCTP:
+==========+===================================+===========+
| ID Value | Chunk Parameter Type | Reference |
+==========+===================================+===========+
| 32769 | Zero Checksum Acceptable (0x8001) | [RFCXXXX] |
+----------+-----------------------------------+-----------+
Table 1: New entry in "Chunk Parameter Types" registry
7. Security Considerations
This document does not change the considerations given in [RFC9260].
8. References
8.1. Normative References
[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>.
[RFC8261] Tuexen, M., Stewart, R., Jesup, R., and S. Loreto,
"Datagram Transport Layer Security (DTLS) Encapsulation of
SCTP Packets", RFC 8261, DOI 10.17487/RFC8261, November
2017, <https://www.rfc-editor.org/info/rfc8261>.
[RFC9260] Stewart, R., Tüxen, M., and K. Nielsen, "Stream Control
Transmission Protocol", RFC 9260, DOI 10.17487/RFC9260,
June 2022, <https://www.rfc-editor.org/info/rfc9260>.
8.2. Informative References
[RFC6458] Stewart, R., Tuexen, M., Poon, K., Lei, P., and V.
Yasevich, "Sockets API Extensions for the Stream Control
Transmission Protocol (SCTP)", RFC 6458,
DOI 10.17487/RFC6458, December 2011,
<https://www.rfc-editor.org/info/rfc6458>.
Authors' Addresses
Tüxen, et al. Expires 27 April 2023 [Page 5]
Internet-Draft Zero Checksum for SCTP October 2022
Michael Tüxen
Münster University of Applied Sciences
Stegerwaldstrasse 39
48565 Steinfurt
Germany
Email: tuexen@fh-muenster.de
Victor Boivie
Google
Kungsbron 2
SE-11122 Stockholm
Sweden
Email: boivie@google.com
Florent Castelli
Google
Kungsbron 2
SE-11122 Stockholm
Sweden
Email: orphis@google.com
Randell Jesup
Mozilla Corporation
1835 Horse Shoe Trl
Malvern, PA 19355
United States of America
Email: randell-ietf@jesup.org
Tüxen, et al. Expires 27 April 2023 [Page 6]