Internet DRAFT - draft-ietf-quic-reliable-stream-reset
draft-ietf-quic-reliable-stream-reset
QUIC M. Seemann
Internet-Draft
Intended status: Standards Track 奥一穂 (K. Oku)
Expires: 1 September 2024 Fastly
29 February 2024
QUIC Stream Resets with Partial Delivery
draft-ietf-quic-reliable-stream-reset-06
Abstract
QUIC defines a RESET_STREAM frame to abort sending on a stream. When
a sender resets a stream, it also stops retransmitting STREAM frames
for this stream in the event of packet loss. On the receiving side,
there is no guarantee that any data sent on that stream is delivered.
This document defines a new QUIC frame, the RESET_STREAM_AT frame,
that allows resetting a stream, while guaranteeing delivery of stream
data up to a certain byte offset.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://quicwg.github.io/reliable-stream-reset/draft-ietf-quic-
reliable-stream-reset.html. Status information for this document may
be found at https://datatracker.ietf.org/doc/draft-ietf-quic-
reliable-stream-reset/.
Discussion of this document takes place on the QUIC Working Group
mailing list (mailto:quic@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/quic/. Subscribe at
https://www.ietf.org/mailman/listinfo/quic/.
Source for this draft and an issue tracker can be found at
https://github.com/quicwg/reliable-stream-reset.
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/.
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This Internet-Draft will expire on 1 September 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Negotiating Extension Use . . . . . . . . . . . . . . . . . . 3
4. RESET_STREAM_AT Frame . . . . . . . . . . . . . . . . . . . . 4
5. Resetting Streams . . . . . . . . . . . . . . . . . . . . . . 5
5.1. Multiple RESET_STREAM_AT / RESET_STREAM frames . . . . . 5
5.2. Stream States . . . . . . . . . . . . . . . . . . . . . . 6
6. Implementation Guidance . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8.1. QUIC Transport Parameter . . . . . . . . . . . . . . . . 7
8.2. QUIC Frame Types . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
QUIC version 1 ([RFC9000]) allows streams to be reset. When a stream
is reset, the sender doesn't retransmit stream data for the
respective stream. On the receiving side, the QUIC stack is free to
surface the stream reset to the application immediately, without
providing any stream data it has received for that stream.
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Some applications running on top of QUIC use bytes at the beginning
of the stream to communicate critical information related to that
stream. For example, WebTransport ([WEBTRANSPORT]) uses a variable-
length encoded integer to associate a stream with a particular
WebTransport session.
Since QUIC does not provide guaranteed delivery of steam data for
reset streams, it is possible that a receiver is unable to read
critical information. In the example above, a reset stream can cause
the receiver to fail to associate incoming streams with their
respective subcomponent of the application. Therefore, it is
desirable that the receiver can rely on the delivery of critical
information to applications, even if the QUIC stream is reset before
data is read by the application.
Another use case is relaying data from an external data source. When
a relay is sending data being read from an external source and
encounters an error, it might want to use a stream reset to signal
that error, while at the same time guaranteeing that all data
received from the source is delivered to the peer.
This document extends QUIC with a variant of stream resets that
reliably delivers the beginning of a stream up to a sender-specified
offset, communicated using the RESET_STREAM_AT frame. It can be
considered a form of range-based partial reliability. As a variant
of reset, application protocols continue to treat this stream
function as an abrupt termination; see Section 2.4 of [RFC9000].
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. Negotiating Extension Use
Endpoints advertise their support of the extension described in this
document by sending the reliable_stream_reset (0x17f7586d2cb571)
transport parameter (Section 7.4 of [RFC9000]) with an empty value.
An implementation that understands this transport parameter MUST
treat the receipt of a non-empty value as a connection error of type
TRANSPORT_PARAMETER_ERROR.
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When using 0-RTT, both endpoints MUST remember the value of this
transport parameter. This allows use of this extension in 0-RTT
packets. When the server accepts 0-RTT data, the server MUST NOT
disable this extension on the resumed connection.
4. RESET_STREAM_AT Frame
Conceptually, the RESET_STREAM_AT frame is a RESET_STREAM frame with
an added Reliable Size field.
RESET_STREAM_AT Frame {
Type (i) = 0x24,
Stream ID (i),
Application Protocol Error Code (i),
Final Size (i),
Reliable Size (i),
}
Figure 1: RESET_STREAM_AT Frame Format
The RESET_STREAM_AT frame contains the following fields:
Stream ID: A variable-length integer encoding of the stream ID of
the stream being terminated.
Application Protocol Error Code: A variable-length integer
containing the application protocol error code (Section 20.2 of
[RFC9000]) that indicates why the stream is being closed.
Final Size: A variable-length integer indicating the final size of
the stream by the sender, in units of bytes; see Section 4.5 of
[RFC9000].
Reliable Size: A variable-length integer indicating the amount of
data that needs to be delivered to the application even though the
stream is reset.
If the Reliable Size is larger than the Final Size, the receiver MUST
close the connection with a connection error of type
FRAME_ENCODING_ERROR.
RESET_STREAM_AT frames are ack-eliciting, and MUST only be sent in
the application data packet number space. When lost, they MUST be
retransmitted, unless the stream state has transitioned to "Data
Recvd" or "Reset Recvd" due to transmission and acknowledgement of
other frames (see Section 5.1).
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5. Resetting Streams
A sender that wants to reset a stream but also deliver some bytes to
the receiver sends a RESET_STREAM_AT frame with the Reliable Size
field specifying the amount of data to be delivered.
When using a RESET_STREAM_AT frame, the initiator MUST guarantee
reliable delivery of stream data of at least Reliable Size bytes. If
STREAM frames containing data up to that byte offset are lost, the
initiator MUST retransmit this data, as described in Section 13.3 of
[RFC9000]. Data sent beyond that byte offset SHOULD NOT be
retransmitted.
As described in Section 3.2 of [RFC9000], a stream reset signal might
be suppressed or withheld, and the same applies to a stream reset
signal carried in a RESET_STREAM_AT frame. Similarly, the Reliable
Size of the RESET_STREAM_AT frame does not prevent a QUIC stack from
delivering data beyond the specified offset to the receiving
application.
Note that a Reliable Size value of zero is valid. A RESET_STREAM_AT
frame with this value is logically equivalent to a RESET_STREAM frame
(Section 3.2 of [RFC9000]). When resetting a stream without the
intent to deliver any data to the receiver, the sender MAY use either
RESET_STREAM or RESET_STREAM_AT with a Reliable Size of zero.
5.1. Multiple RESET_STREAM_AT / RESET_STREAM frames
The initiator MAY send multiple RESET_STREAM_AT frames for the same
stream in order to reduce the Reliable Size. It MAY also send a
RESET_STREAM frame, which is equivalent to sending a RESET_STREAM_AT
frame with a Reliable Size of 0. When reducing the Reliable Size,
the sender MUST retransmit the RESET_STREAM_AT frame carrying the
smallest Reliable Size as well as stream data up to that size, until
all acknowledgements for the stream data and the RESET_STREAM_AT
frame are received.
When sending multiple RESET_STREAM_AT or RESET_STREAM frames for the
same stream, the initiator MUST NOT increase the Reliable Size.
When receiving a RESET_STREAM_AT frame with a lower Reliable Size,
the receiver only needs to provide data up the lower Reliable Size to
the application. It MUST NOT expect the sender to deliver any data
beyond that byte offset.
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Reordering of packets might lead to a RESET_STREAM_AT frame with a
higher Reliable Size being received after a RESET_STREAM_AT frame
with a lower Reliable Size. The receiver MUST ignore any
RESET_STREAM_AT frame that increases the Reliable Size.
When sending another RESET_STREAM_AT, RESET_STREAM or STREAM frame
carrying a FIN bit for the same stream, the initiator MUST NOT change
the Application Error Code or the Final Size. If the receiver
detects a change in those fields, it MUST close the connection with a
connection error of type STREAM_STATE_ERROR.
While multiple RESET_STREAM_AT frames can reduce Reliable Size, some
applications might need to ensure that a minimum amount of data is
always delivered on a stream. Application protocols can establish
rules for streams that ensure that Reliable Size is not reduced below
a certain threshold if that is necessary to ensure correct operation
of the protocol.
5.2. Stream States
In terms of stream state transitions (Section 3 of [RFC9000]), the
effect of a RESET_STREAM_AT frame is equivalent to that of the FIN
bit. Both the RESET_STREAM_AT frame and the FIN bit on a STREAM
frame serve the same role: signaling the amount of data to be
delivered.
On the sending side, when the first RESET_STREAM_AT frame is sent,
the sending part of the stream enters the "Data Sent" state. Once
the RESET_STREAM_AT frame carrying the smallest Reliable Size and all
stream data up to that byte offset have been acknowledged, the
sending part of the stream enters the "Data Recvd" state. The
transition from "Data Sent" to "Data Recvd" happens immediately if
the application resets a stream and all bytes up to the specified
Reliable Size have already been sent and acknowledged. Conversely,
the transition might take multiple network roundtrips or require
additional flow control credit issued by the receiver.
On the receiving side, when a RESET_STREAM_AT frame is received, the
receiving part of the stream enters the "Size Known" state. Once all
data up to the smallest Reliable Size have been received, it enters
the "Data Recvd" state. Similarly to the sending side, transition
from "Size Known" to "Data Recvd" might happen immediately or involve
issuance of additional flow control credit.
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6. Implementation Guidance
In terms of transport machinery, the RESET_STREAM_AT frame is more
akin to the FIN bit than to the RESET_STREAM frame (see Section 5.2).
By sending a RESET_STREAM_AT frame, the sender commits to delivering
all bytes up to the Reliable Size.
To the endpoints, the main differences from closing a stream by using
the FIN bit are:
* the offset up to which the sender commits to sending might be
smaller than Final Size,
* this offset might get reduced by subsequent RESET_STREAM_AT
frames, and
* the closure is accompanied by an error code.
7. Security Considerations
As the RESET_STREAM_AT frame is an extension to the stream machinery
defined in QUIC version 1, the security considerations of [RFC9000]
apply accordingly. Specifically, given that RESET_STREAM_AT frames
indicate the offset up to which data is reliably transmitted,
endpoints SHOULD remain vigilant against resource commitment and
exhaustion attacks even after sending or receiving RESET_STREAM_AT
frames, until the stream reaches the terminal state.
8. IANA Considerations
8.1. QUIC Transport Parameter
This document registers the reliable_stream_reset transport parameter
in the "QUIC Transport Parameters" registry established in
Section 22.3 of [RFC9000]. The following fields are registered:
Value: 0x17f7586d2cb571
Parameter Name: reliable_stream_reset
Status: Provisional (note that, prior to publication, the value will
be replaced by a new value lower than 64)
Specification: This document
Change Controller: IETF (iesg@ietf.org)
Contact: QUIC Working Group (quic@ietf.org)
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8.2. QUIC Frame Types
This document registers one new value in the "QUIC Frame Types"
registry established in Section 22.4 of [RFC9000]. The following
fields are registered:
Value: 0x24
Frame Type Name: RESET_STREAM_AT
Status: Provisional (will become Permanent once this document is
approved)
Specification: This document
Change Controller: IETF (iesg@ietf.org)
Contact: QUIC Working Group (quic@ietf.org)
9. References
9.1. 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/rfc/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/rfc/rfc8174>.
[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/rfc/rfc9000>.
9.2. Informative References
[WEBTRANSPORT]
Frindell, A., Kinnear, E., and V. Vasiliev, "WebTransport
over HTTP/3", Work in Progress, Internet-Draft, draft-
ietf-webtrans-http3-08, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-
webtrans-http3-08>.
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Acknowledgments
TODO acknowledge.
Authors' Addresses
Marten Seemann
Email: martenseemann@gmail.com
Kazuho Oku
Fastly
Email: kazuhooku@gmail.com
Additional contact information:
奥一穂
Fastly
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