QUIC                                                             R. Marx
Internet-Draft                                                 KU Leuven
Intended status: Standards Track                       L. Niccolini, Ed.
Expires: 12 December 2021                                       Facebook
                                                         M. Seemann, Ed.
                                                           Protocol Labs
                                                            10 June 2021


              HTTP/3 and QPACK event definitions for qlog
                   draft-ietf-quic-qlog-h3-events-00

Abstract

   This document describes concrete qlog event definitions and their
   metadata for HTTP/3 and QPACK-related events.  These events can then
   be embedded in the higher level schema defined in [QLOG-MAIN].

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 12 December 2021.

Copyright Notice

   Copyright (c) 2021 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 (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 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.



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Usage with QUIC . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  Links to the main schema  . . . . . . . . . . . . . . . .   4
       2.2.1.  Raw packet and frame information  . . . . . . . . . .   4
   3.  HTTP/3 and QPACK event definitions  . . . . . . . . . . . . .   5
     3.1.  http  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
       3.1.1.  parameters_set  . . . . . . . . . . . . . . . . . . .   5
       3.1.2.  parameters_restored . . . . . . . . . . . . . . . . .   6
       3.1.3.  stream_type_set . . . . . . . . . . . . . . . . . . .   6
       3.1.4.  frame_created . . . . . . . . . . . . . . . . . . . .   7
       3.1.5.  frame_parsed  . . . . . . . . . . . . . . . . . . . .   8
       3.1.6.  push_resolved . . . . . . . . . . . . . . . . . . . .   8
     3.2.  qpack . . . . . . . . . . . . . . . . . . . . . . . . . .   9
       3.2.1.  state_updated . . . . . . . . . . . . . . . . . . . .   9
       3.2.2.  stream_state_updated  . . . . . . . . . . . . . . . .   9
       3.2.3.  dynamic_table_updated . . . . . . . . . . . . . . . .  10
       3.2.4.  headers_encoded . . . . . . . . . . . . . . . . . . .  10
       3.2.5.  headers_decoded . . . . . . . . . . . . . . . . . . .  11
       3.2.6.  instruction_created . . . . . . . . . . . . . . . . .  11
       3.2.7.  instruction_parsed  . . . . . . . . . . . . . . . . .  12
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Appendix A.  HTTP/3 data field definitions  . . . . . . . . . . .  13
     A.1.  HTTP/3 Frames . . . . . . . . . . . . . . . . . . . . . .  13
       A.1.1.  DataFrame . . . . . . . . . . . . . . . . . . . . . .  13
       A.1.2.  HeadersFrame  . . . . . . . . . . . . . . . . . . . .  14
       A.1.3.  CancelPushFrame . . . . . . . . . . . . . . . . . . .  14
       A.1.4.  SettingsFrame . . . . . . . . . . . . . . . . . . . .  14
       A.1.5.  PushPromiseFrame  . . . . . . . . . . . . . . . . . .  14
       A.1.6.  GoAwayFrame . . . . . . . . . . . . . . . . . . . . .  15
       A.1.7.  MaxPushIDFrame  . . . . . . . . . . . . . . . . . . .  15
       A.1.8.  DuplicatePushFrame  . . . . . . . . . . . . . . . . .  15
       A.1.9.  ReservedFrame . . . . . . . . . . . . . . . . . . . .  15
       A.1.10. UnknownFrame  . . . . . . . . . . . . . . . . . . . .  15
     A.2.  ApplicationError  . . . . . . . . . . . . . . . . . . . .  15
   Appendix B.  QPACK DATA type definitions  . . . . . . . . . . . .  16
     B.1.  QPACK Instructions  . . . . . . . . . . . . . . . . . . .  16
       B.1.1.  SetDynamicTableCapacityInstruction  . . . . . . . . .  16
       B.1.2.  InsertWithNameReferenceInstruction  . . . . . . . . .  16
       B.1.3.  InsertWithoutNameReferenceInstruction . . . . . . . .  17
       B.1.4.  DuplicateInstruction  . . . . . . . . . . . . . . . .  17



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       B.1.5.  HeaderAcknowledgementInstruction  . . . . . . . . . .  17
       B.1.6.  StreamCancellationInstruction . . . . . . . . . . . .  17
       B.1.7.  InsertCountIncrementInstruction . . . . . . . . . . .  18
     B.2.  QPACK Header compression  . . . . . . . . . . . . . . . .  18
       B.2.1.  IndexedHeaderField  . . . . . . . . . . . . . . . . .  18
       B.2.2.  LiteralHeaderFieldWithName  . . . . . . . . . . . . .  18
       B.2.3.  LiteralHeaderFieldWithoutName . . . . . . . . . . . .  19
       B.2.4.  QPackHeaderBlockPrefix  . . . . . . . . . . . . . . .  19
   Appendix C.  Change Log . . . . . . . . . . . . . . . . . . . . .  19
     C.1.  Since draft-marx-qlog-event-definitions-quic-h3-02: . . .  19
     C.2.  Since draft-marx-qlog-event-definitions-quic-h3-01: . . .  20
     C.3.  Since draft-marx-qlog-event-definitions-quic-h3-00: . . .  21
   Appendix D.  Design Variations  . . . . . . . . . . . . . . . . .  22
   Appendix E.  Acknowledgements . . . . . . . . . . . . . . . . . .  22
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22

1.  Introduction

   This document describes the values of the qlog name ("category" +
   "event") and "data" fields and their semantics for the HTTP/3 and
   QPACK protocols.  This document is based on draft-34 of the HTTP/3
   I-D [QUIC-HTTP] and draft-21 of the QPACK I-D [QUIC-QPACK].  QUIC
   events are defined in a separate document [QLOG-QUIC].

   Feedback and discussion are welcome at https://github.com/quicwg/qlog
   (https://github.com/quicwg/qlog).  Readers are advised to refer to
   the "editor's draft" at that URL for an up-to-date version of this
   document.

   Concrete examples of integrations of this schema in various
   programming languages can be found at https://github.com/quiclog/
   qlog/ (https://github.com/quiclog/qlog/).

1.1.  Notational Conventions

   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].

   The examples and data definitions in ths document are expressed in a
   custom data definition language, inspired by JSON and TypeScript, and
   described in [QLOG-MAIN].

2.  Overview

   This document describes the values of the qlog "name" ("category" +
   "event") and "data" fields and their semantics for the HTTP/3 and
   QPACK protocols.



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   This document assumes the usage of the encompassing main qlog schema
   defined in [QLOG-MAIN].  Each subsection below defines a separate
   category (for example http, qpack) and each subsubsection is an event
   type (for example "frame_created").

   For each event type, its importance and data definition is laid out,
   often accompanied by possible values for the optional "trigger"
   field.  For the definition and semantics of "importance" and
   "trigger", see the main schema document.

   Most of the complex datastructures, enums and re-usable definitions
   are grouped together on the bottom of this document for clarity.

2.1.  Usage with QUIC

   The events described in this document can be used with or without
   logging the related QUIC events defined in [QLOG-QUIC].  If used with
   QUIC events, the QUIC document takes precedence in terms of
   recommended filenames and trace separation setups.

   If used without QUIC events, it is recommended that the
   implementation assign a globally unique identifier to each HTTP/3
   connection.  This ID can then be used as the value of the qlog
   "group_id" field, as well as the qlog filename or file identifier,
   potentially suffixed by the vantagepoint type (For example,
   abcd1234_server.qlog would contain the server-side trace of the
   connection with GUID abcd1234).

2.2.  Links to the main schema

   This document re-uses all the fields defined in the main qlog schema
   (e.g., name, category, type, data, group_id, protocol_type, the time-
   related fields, importance, RawInfo, etc.).

   One entry in the "protocol_type" qlog array field MUST be "HTTP3" if
   events from this document are included in a qlog trace.

2.2.1.  Raw packet and frame information

   This document re-uses the definition of the RawInfo data class from
   [QLOG-MAIN].

   Note:  As HTTP/3 does not use trailers in frames, each HTTP/3 frame
      header_length can be calculated as header_length = RawInfo:length
      - RawInfo:payload_length

   Note:  In some cases, the length fields are also explicitly reflected




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      inside of frame headers.  For example, all HTTP/3 frames include
      their explicit payload lengths in the frame header.  In these
      cases, those fields are intentionally preserved in the event
      definitions.  Even though this can lead to duplicate data when the
      full RawInfo is logged, it allows a more direct mapping of the
      HTTP/3 specifications to qlog, making it easier for users to
      interpret.  In this case, both fields MUST have the same value.

3.  HTTP/3 and QPACK event definitions

   Each subheading in this section is a qlog event category, while each
   sub-subheading is a qlog event type.

   For example, for the following two items, we have the category "http"
   and event type "parameters_set", resulting in a concatenated qlog
   "name" field value of "http:parameters_set".

3.1.  http

   Note: like all category values, the "http" category is written in
   lowercase.

3.1.1.  parameters_set

   Importance: Base

   This event contains HTTP/3 and QPACK-level settings, mostly those
   received from the HTTP/3 SETTINGS frame.  All these parameters are
   typically set once and never change.  However, they are typically set
   at different times during the connection, so there can be several
   instances of this event with different fields set.

   Note that some settings have two variations (one set locally, one
   requested by the remote peer).  This is reflected in the "owner"
   field.  As such, this field MUST be correct for all settings included
   a single event instance.  If you need to log settings from two sides,
   you MUST emit two separate event instances.

   Data:












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{
    owner?:"local" | "remote",

    max_header_list_size?:uint64, // from SETTINGS_MAX_HEADER_LIST_SIZE
    max_table_capacity?:uint64, // from SETTINGS_QPACK_MAX_TABLE_CAPACITY
    blocked_streams_count?:uint64, // from SETTINGS_QPACK_BLOCKED_STREAMS

    // qlog-defined
    waits_for_settings?:boolean // indicates whether this implementation waits for a SETTINGS frame before processing requests
}

   Note: enabling server push is not explicitly done in HTTP/3 by use of
   a setting or parameter.  Instead, it is communicated by use of the
   MAX_PUSH_ID frame, which should be logged using the frame_created and
   frame_parsed events below.

   Additionally, this event can contain any number of unspecified
   fields.  This is to reflect setting of for example unknown (greased)
   settings or parameters of (proprietary) extensions.

3.1.2.  parameters_restored

   Importance: Base

   When using QUIC 0-RTT, HTTP/3 clients are expected to remember and
   reuse the server's SETTINGs from the previous connection.  This event
   is used to indicate which HTTP/3 settings were restored and to which
   values when utilizing 0-RTT.

   Data:

   {
       max_header_list_size?:uint64,
       max_table_capacity?:uint64,
       blocked_streams_count?:uint64
   }

   Note that, like for parameters_set above, this event can contain any
   number of unspecified fields to allow for additional and custom
   settings.

3.1.3.  stream_type_set

   Importance: Base

   Emitted when a stream's type becomes known.  This is typically when a
   stream is opened and the stream's type indicator is sent or received.




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   Note: most of this information can also be inferred by looking at a
   stream's id, since id's are strictly partitioned at the QUIC level.
   Even so, this event has a "Base" importance because it helps a lot in
   debugging to have this information clearly spelled out.

   Data:

   {
       stream_id:uint64,

       owner?:"local"|"remote"

       old?:StreamType,
       new:StreamType,

       associated_push_id?:uint64 // only when new == "push"
   }

   enum StreamType {
       data, // bidirectional request-response streams
       control,
       push,
       reserved,
       qpack_encode,
       qpack_decode
   }

3.1.4.  frame_created

   Importance: Core

   HTTP equivalent to the packet_sent event.  This event is emitted when
   the HTTP/3 framing actually happens.  Note: this is not necessarily
   the same as when the HTTP/3 data is passed on to the QUIC layer.  For
   that, see the "data_moved" event in [QLOG-QUIC].

   Data:

   {
       stream_id:uint64,
       length?:uint64, // payload byte length of the frame
       frame:HTTP3Frame, // see appendix for the definitions,

       raw?:RawInfo
   }






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   Note: in HTTP/3, DATA frames can have arbitrarily large lengths to
   reduce frame header overhead.  As such, DATA frames can span many
   QUIC packets and can be created in a streaming fashion.  In this
   case, the frame_created event is emitted once for the frame header,
   and further streamed data is indicated using the data_moved event.

3.1.5.  frame_parsed

   Importance: Core

   HTTP equivalent to the packet_received event.  This event is emitted
   when we actually parse the HTTP/3 frame.  Note: this is not
   necessarily the same as when the HTTP/3 data is actually received on
   the QUIC layer.  For that, see the "data_moved" event in [QLOG-QUIC].

   Data:

   {
       stream_id:uint64,
       length?:uint64, // payload byte length of the frame
       frame:HTTP3Frame, // see appendix for the definitions,

       raw?:RawInfo
   }

   Note: in HTTP/3, DATA frames can have arbitrarily large lengths to
   reduce frame header overhead.  As such, DATA frames can span many
   QUIC packets and can be processed in a streaming fashion.  In this
   case, the frame_parsed event is emitted once for the frame header,
   and further streamed data is indicated using the data_moved event.

3.1.6.  push_resolved

   Importance: Extra

   This event is emitted when a pushed resource is successfully claimed
   (used) or, conversely, abandoned (rejected) by the application on top
   of HTTP/3 (e.g., the web browser).  This event is added to help debug
   problems with unexpected PUSH behaviour, which is commonplace with
   HTTP/2.

{
    push_id?:uint64,
    stream_id?:uint64, // in case this is logged from a place that does not have access to the push_id

    decision:"claimed"|"abandoned"
}




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3.2.  qpack

   Note: like all category values, the "qpack" category is written in
   lowercase.

   The QPACK events mainly serve as an aid to debug low-level QPACK
   issues.  The higher-level, plaintext header values SHOULD (also) be
   logged in the http.frame_created and http.frame_parsed event data
   (instead).

   Note: qpack does not have its own parameters_set event.  This was
   merged with http.parameters_set for brevity, since qpack is a
   required extension for HTTP/3 anyway.  Other HTTP/3 extensions MAY
   also log their SETTINGS fields in http.parameters_set or MAY define
   their own events.

3.2.1.  state_updated

   Importance: Base

   This event is emitted when one or more of the internal QPACK
   variables changes value.  Note that some variables have two
   variations (one set locally, one requested by the remote peer).  This
   is reflected in the "owner" field.  As such, this field MUST be
   correct for all variables included a single event instance.  If you
   need to log settings from two sides, you MUST emit two separate event
   instances.

   Data:

{
    owner:"local" | "remote",

    dynamic_table_capacity?:uint64,
    dynamic_table_size?:uint64, // effective current size, sum of all the entries

    known_received_count?:uint64,
    current_insert_count?:uint64
}

3.2.2.  stream_state_updated

   Importance: Core

   This event is emitted when a stream becomes blocked or unblocked by
   header decoding requests or QPACK instructions.





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   Note: This event is of "Core" importance, as it might have a large
   impact on HTTP/3's observed performance.

   Data:

{
    stream_id:uint64,

    state:"blocked"|"unblocked" // streams are assumed to start "unblocked" until they become "blocked"
}

3.2.3.  dynamic_table_updated

   Importance: Extra

   This event is emitted when one or more entries are inserted or
   evicted from QPACK's dynamic table.

   Data:

{
    owner:"local" | "remote", // local = the encoder's dynamic table. remote = the decoder's dynamic table

    update_type:"inserted"|"evicted",

    entries:Array<DynamicTableEntry>
}

class DynamicTableEntry {
    index:uint64;
    name?:string | bytes;
    value?:string | bytes;
}

3.2.4.  headers_encoded

   Importance: Base

   This event is emitted when an uncompressed header block is encoded
   successfully.

   Note: this event has overlap with http.frame_created for the
   HeadersFrame type.  When outputting both events, implementers MAY
   omit the "headers" field in this event.

   Data:





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   {
       stream_id?:uint64,

       headers?:Array<HTTPHeader>,

       block_prefix:QPackHeaderBlockPrefix,
       header_block:Array<QPackHeaderBlockRepresentation>,

       length?:uint32,
       raw?:bytes
   }

3.2.5.  headers_decoded

   Importance: Base

   This event is emitted when a compressed header block is decoded
   successfully.

   Note: this event has overlap with http.frame_parsed for the
   HeadersFrame type.  When outputting both events, implementers MAY
   omit the "headers" field in this event.

   Data:

   {
       stream_id?:uint64,

       headers?:Array<HTTPHeader>,

       block_prefix:QPackHeaderBlockPrefix,
       header_block:Array<QPackHeaderBlockRepresentation>,

       length?:uint32,
       raw?:bytes
   }

3.2.6.  instruction_created

   Importance: Base

   This event is emitted when a QPACK instruction (both decoder and
   encoder) is created and added to the encoder/decoder stream.

   Data:






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   {
       instruction:QPackInstruction // see appendix for the definitions,

       length?:uint32,
       raw?:bytes
   }

   Note: encoder/decoder semantics and stream_id's are implicit in
   either the instruction types or can be logged via other events (e.g.,
   http.stream_type_set)

3.2.7.  instruction_parsed

   Importance: Base

   This event is emitted when a QPACK instruction (both decoder and
   encoder) is read from the encoder/decoder stream.

   Data:

   {
       instruction:QPackInstruction // see appendix for the definitions,

       length?:uint32,
       raw?:bytes
   }

   Note: encoder/decoder semantics and stream_id's are implicit in
   either the instruction types or can be logged via other events (e.g.,
   http.stream_type_set)

4.  Security Considerations

   TBD

5.  IANA Considerations

   TBD

6.  References

6.1.  Normative References









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   [QLOG-MAIN]
              Marx, R., Ed., Niccolini, L., Ed., and M. Seemann, Ed.,
              "Main logging schema for qlog", Work in Progress,
              Internet-Draft, draft-ietf-quic-qlog-main-schema-00,
              <https://tools.ietf.org/html/draft-ietf-quic-qlog-main-
              schema-00>.

   [QLOG-QUIC]
              Marx, R., Ed., Niccolini, L., Ed., and M. Seemann, Ed.,
              "QUIC event definitions for qlog", Work in Progress,
              Internet-Draft, draft-ietf-quic-qlog-quic-events-00,
              <https://tools.ietf.org/html/draft-ietf-quic-qlog-quic-
              events-00>.

   [QUIC-HTTP]
              Bishop, M., Ed., "Hypertext Transfer Protocol Version 3
              (HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
              quic-http-latest,
              <https://tools.ietf.org/html/draft-ietf-quic-http-latest>.

   [QUIC-QPACK]
              Krasic, C., Bishop, M., and A. Frindell, Ed., "QPACK:
              Header Compression for HTTP over QUIC", Work in Progress,
              Internet-Draft, draft-ietf-quic-qpack-latest,
              <https://tools.ietf.org/html/draft-ietf-quic-qpack-
              latest>.

6.2.  Informative 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>.

Appendix A.  HTTP/3 data field definitions

A.1.  HTTP/3 Frames

type HTTP3Frame = DataFrame | HeadersFrame | PriorityFrame | CancelPushFrame | SettingsFrame | PushPromiseFrame | GoAwayFrame | MaxPushIDFrame | DuplicatePushFrame | ReservedFrame | UnknownFrame;

A.1.1.  DataFrame

   class DataFrame{
       frame_type:string = "data";

       raw?:bytes;
   }




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A.1.2.  HeadersFrame

   This represents an _uncompressed_, plaintext HTTP Headers frame
   (e.g., no QPACK compression is applied).

   For example:

headers: [{"name":":path","value":"/"},{"name":":method","value":"GET"},{"name":":authority","value":"127.0.0.1:4433"},{"name":":scheme","value":"https"}]

   class HeadersFrame{
       frame_type:string = "header";
       headers:Array<HTTPHeader>;
   }

   class HTTPHeader {
       name:string;
       value:string;
   }

A.1.3.  CancelPushFrame

   class CancelPushFrame{
       frame_type:string = "cancel_push";
       push_id:uint64;
   }

A.1.4.  SettingsFrame

   class SettingsFrame{
       frame_type:string = "settings";
       settings:Array<Setting>;
   }

   class Setting{
       name:string;
       value:string;
   }

A.1.5.  PushPromiseFrame

   class PushPromiseFrame{
       frame_type:string = "push_promise";
       push_id:uint64;

       headers:Array<HTTPHeader>;
   }





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A.1.6.  GoAwayFrame

   class GoAwayFrame{
       frame_type:string = "goaway";
       stream_id:uint64;
   }

A.1.7.  MaxPushIDFrame

   class MaxPushIDFrame{
       frame_type:string = "max_push_id";
       push_id:uint64;
   }

A.1.8.  DuplicatePushFrame

   class DuplicatePushFrame{
       frame_type:string = "duplicate_push";
       push_id:uint64;
   }

A.1.9.  ReservedFrame

   class ReservedFrame{
       frame_type:string = "reserved";
   }

A.1.10.  UnknownFrame

   HTTP/3 re-uses QUIC's UnknownFrame definition, since their values and
   usage overlaps.  See [QLOG-QUIC].

A.2.  ApplicationError


















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   enum ApplicationError{
       http_no_error,
       http_general_protocol_error,
       http_internal_error,
       http_stream_creation_error,
       http_closed_critical_stream,
       http_frame_unexpected,
       http_frame_error,
       http_excessive_load,
       http_id_error,
       http_settings_error,
       http_missing_settings,
       http_request_rejected,
       http_request_cancelled,
       http_request_incomplete,
       http_early_response,
       http_connect_error,
       http_version_fallback
   }

Appendix B.  QPACK DATA type definitions

B.1.  QPACK Instructions

   Note: the instructions do not have explicit encoder/decoder types,
   since there is no overlap between the insturctions of both types in
   neither name nor function.

type QPackInstruction = SetDynamicTableCapacityInstruction | InsertWithNameReferenceInstruction | InsertWithoutNameReferenceInstruction | DuplicateInstruction | HeaderAcknowledgementInstruction | StreamCancellationInstruction | InsertCountIncrementInstruction;

B.1.1.  SetDynamicTableCapacityInstruction

   class SetDynamicTableCapacityInstruction {
       instruction_type:string = "set_dynamic_table_capacity";

       capacity:uint32;
   }

B.1.2.  InsertWithNameReferenceInstruction












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   class InsertWithNameReferenceInstruction {
       instruction_type:string = "insert_with_name_reference";

       table_type:"static"|"dynamic";

       name_index:uint32;

       huffman_encoded_value:boolean;

       value_length?:uint32;
       value?:string;
   }

B.1.3.  InsertWithoutNameReferenceInstruction

   class InsertWithoutNameReferenceInstruction {
       instruction_type:string = "insert_without_name_reference";

       huffman_encoded_name:boolean;

       name_length?:uint32;
       name?:string;

       huffman_encoded_value:boolean;

       value_length?:uint32;
       value?:string;
   }

B.1.4.  DuplicateInstruction

   class DuplicateInstruction {
       instruction_type:string = "duplicate";

       index:uint32;
   }

B.1.5.  HeaderAcknowledgementInstruction

   class HeaderAcknowledgementInstruction {
       instruction_type:string = "header_acknowledgement";

       stream_id:uint64;
   }

B.1.6.  StreamCancellationInstruction





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   class StreamCancellationInstruction {
       instruction_type:string = "stream_cancellation";

       stream_id:uint64;
   }

B.1.7.  InsertCountIncrementInstruction

   class InsertCountIncrementInstruction {
       instruction_type:string = "insert_count_increment";

       increment:uint32;
   }

B.2.  QPACK Header compression

type QPackHeaderBlockRepresentation = IndexedHeaderField | LiteralHeaderFieldWithName | LiteralHeaderFieldWithoutName;

B.2.1.  IndexedHeaderField

   Note: also used for "indexed header field with post-base index"

class IndexedHeaderField {
    header_field_type:string = "indexed_header";

    table_type:"static"|"dynamic"; // MUST be "dynamic" if is_post_base is true
    index:uint32;

    is_post_base:boolean = false; // to represent the "indexed header field with post-base index" header field type
}

B.2.2.  LiteralHeaderFieldWithName

   Note: also used for "Literal header field with post-base name
   reference"
















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class LiteralHeaderFieldWithName {
    header_field_type:string = "literal_with_name";

    preserve_literal:boolean; // the 3rd "N" bit
    table_type:"static"|"dynamic"; // MUST be "dynamic" if is_post_base is true
    name_index:uint32;

    huffman_encoded_value:boolean;
    value_length?:uint32;
    value?:string;

    is_post_base:boolean = false; // to represent the "Literal header field with post-base name reference" header field type
}

B.2.3.  LiteralHeaderFieldWithoutName

   class LiteralHeaderFieldWithoutName {
       header_field_type:string = "literal_without_name";

       preserve_literal:boolean; // the 3rd "N" bit

       huffman_encoded_name:boolean;
       name_length?:uint32;
       name?:string;

       huffman_encoded_value:boolean;
       value_length?:uint32;
       value?:string;
   }

B.2.4.  QPackHeaderBlockPrefix

   class QPackHeaderBlockPrefix {
       required_insert_count:uint32;
       sign_bit:boolean;
       delta_base:uint32;
   }

Appendix C.  Change Log

C.1.  Since draft-marx-qlog-event-definitions-quic-h3-02:

   *  These changes were done in preparation of the adoption of the
      drafts by the QUIC working group (#137)

   *  Split QUIC and HTTP/3 events into two separate documents





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   *  Moved RawInfo, Importance, Generic events and Simulation events to
      the main schema document.

C.2.  Since draft-marx-qlog-event-definitions-quic-h3-01:

   Major changes:

   *  Moved data_moved from http to transport.  Also made the "from" and
      "to" fields flexible strings instead of an enum (#111,#65)

   *  Moved packet_type fields to PacketHeader.  Moved packet_size field
      out of PacketHeader to RawInfo:length (#40)

   *  Made events that need to log packet_type and packet_number use a
      header field instead of logging these fields individually

   *  Added support for logging retry, stateless reset and initial
      tokens (#94,#86,#117)

   *  Moved separate general event categories into a single category
      "generic" (#47)

   *  Added "transport:connection_closed" event (#43,#85,#78,#49)

   *  Added version_information and alpn_information events
      (#85,#75,#28)

   *  Added parameters_restored events to help clarify 0-RTT behaviour
      (#88)

   Smaller changes:

   *  Merged loss_timer events into one loss_timer_updated event

   *  Field data types are now strongly defined (#10,#39,#36,#115)

   *  Renamed qpack instruction_received and instruction_sent to
      instruction_created and instruction_parsed (#114)

   *  Updated qpack:dynamic_table_updated.update_type.  It now has the
      value "inserted" instead of "added" (#113)

   *  Updated qpack:dynamic_table_updated.  It now has an "owner" field
      to differentiate encoder vs decoder state (#112)

   *  Removed push_allowed from http:parameters_set (#110)





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   *  Removed explicit trigger field indications from events, since this
      was moved to be a generic property of the "data" field (#80)

   *  Updated transport:connection_id_updated to be more in line with
      other similar events.  Also dropped importance from Core to Base
      (#45)

   *  Added length property to PaddingFrame (#34)

   *  Added packet_number field to transport:frames_processed (#74)

   *  Added a way to generically log packet header flags (first 8 bits)
      to PacketHeader

   *  Added additional guidance on which events to log in which
      situations (#53)

   *  Added "simulation:scenario" event to help indicate simulation
      details

   *  Added "packets_acked" event (#107)

   *  Added "datagram_ids" to the datagram_X and packet_X events to
      allow tracking of coalesced QUIC packets (#91)

   *  Extended connection_state_updated with more fine-grained states
      (#49)

C.3.  Since draft-marx-qlog-event-definitions-quic-h3-00:

   *  Event and category names are now all lowercase

   *  Added many new events and their definitions

   *  "type" fields have been made more specific (especially important
      for PacketType fields, which are now called packet_type instead of
      type)

   *  Events are given an importance indicator (issue #22)

   *  Event names are more consistent and use past tense (issue #21)

   *  Triggers have been redefined as properties of the "data" field and
      updated for most events (issue #23)







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Appendix D.  Design Variations

   TBD

Appendix E.  Acknowledgements

   Much of the initial work by Robin Marx was done at Hasselt
   University.

   Thanks to Marten Seemann, Jana Iyengar, Brian Trammell, Dmitri
   Tikhonov, Stephen Petrides, Jari Arkko, Marcus Ihlar, Victor
   Vasiliev, Mirja Kuehlewind, Jeremy Laine, Kazu Yamamoto, Christian
   Huitema, and Lucas Pardue for their feedback and suggestions.

Authors' Addresses

   Robin Marx
   KU Leuven

   Email: robin.marx@kuleuven.be


   Luca Niccolini (editor)
   Facebook

   Email: lniccolini@fb.com


   Marten Seemann (editor)
   Protocol Labs

   Email: marten@protocol.ai



















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