doc/designs/quic-design/rx-depacketizer.md - third_party/openssl - Git at Google

 RX depacketizer
 ===============

 This component takes a QUIC packet and parses the frames contained therein,
 to be forwarded to appropriate other components for further processing.

 In the [overview], this is called the "RX Frame Handler".  The name "RX
 depacketizer" was chosen to reflect the kinship with the [TX packetizer].

 Main structures
 ---------------

 ### Connection

 Represented by an `QUIC_CONNECTION` object, defined in
 [`include/internal/quic_ssl.h`](../../../include/internal/quic_ssl.h).

 ### Stream

 Represented by an `QUIC_STREAM` object (yet to be defined).

 ### Packets

 Represented by the `OSSL_QRX_PKT` structure, defined in
 `include/internal/quic_record_rx.h` in [QUIC Demuxer and Record Layer (RX+TX)].

 Interactions
 ------------

 The RX depacketizer receives a packet from the QUIC Read Record Layer, and
 then processes frames in two phases:

 1.  [Collect information for the ACK Manager](#collect-information-for-the-ack-manager)
 2.  [Pass frame data](#pass-frame-data)

 ### Other components

 There are a number of other components that the RX depacketizer wants to
 interact with:

 -   [ACK manager]
 -   Handshake manager, which is currently unspecified.  It's assumed that
     this will wrap around what is called the "TLS Handshake Record Layer",
     in the [overview]
 -   Session manager, which is currently unspecified for QUIC, but may very
     well be the existing `SSL_SESSION` functionality, extended to fit QUIC
     purposes.
 -   Flow control, which is currently unspecified.  In the [overview], it's
     called the "Flow Controller And Statistics Collector"
 -   Connection manager, which is currently unspecified.  In the [overview],
     there's a "Connection State Machine" that the "RX Frame Handler" isn't
     talking directly with, so it's possible that the Connection manager will
     turn out to be the Handshake manager.
 -   Stream SSL objects, to pass the stream data to.

 ### Read and process a packet

 Following how things are designed elsewhere, the depacketizer is assumed to
 be called "from above" using the following function:

 ``` C
 __owur int ossl_quic_depacketize(QUIC_CONNECTION *connection);
 ```

 This function would create an `OSSL_QRX_PKT` and call the QUIC Read Record
 Layer with a pointer to it, leaving it to the QUIC Read Record Layer to fill
 in the data.

 This uses the `ossl_qrx_read_pkt()` packet reading function from
 [QUIC Demuxer and Record Layer (RX+TX)].
 (the `OSSL_QRX_PKT` structure / sub-structure needs to be extended to take
 an `OSSL_TIME`, possibly by reference, which should be filled in with the
 packet reception time)

 ### Collect information for the [ACK manager]

 This collects appropriate data into a `QUIC_ACKM_RX_PKT` structure:

 -   The packet number (`packet->packet_number`)
 -   The packet receive time (`received`)
 -   The packet space, which is always:
     -   `QUIC_PN_SPACE_INITIAL` when `packet->packet_type == pkt_initial`
     -   `QUIC_PN_SPACE_HANDSHAKE` when `packet->packet_type == pkt_handshake`
     -   `QUIC_PN_SPACE_APP` for all other packet types
 -   The ACK eliciting flag.  This is calculated by looping through all
     frames and noting those that are ACK eliciting, as determined from
     [Table 1](#table-1) below)

 ### Passing frame data

 This loops through all the frames, extracts data where there is any
 and calls diverse other components as shown in the Passed to column in
 [Table 1](#table-1) below.

 #### Table 1

 Taken from [RFC 9000 12.4 Frames and Frame Types]

 | Type | Name                    | Passed to                | ACK eliciting | I        | H        | 0        | 1        |
 |------|-------------------------|--------------------------|---------------|----------|----------|----------|----------|
 | 0x00 | [padding]               | -                        |               | &#10004; | &#10004; | &#10004; | &#10004; |
 | 0x01 | [ping]                  | -                        | &#10004;      | &#10004; | &#10004; | &#10004; | &#10004; |
 | 0x02 | [ack 0x02]              | [ACK manager] [^1]       |               | &#10004; | &#10004; |          | &#10004; |
 | 0x03 | [ack 0x03]              | [ACK manager] [^1]       |               | &#10004; | &#10004; |          | &#10004; |
 | 0x04 | [reset_stream]          | - [^2]                   | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x05 | [stop_sending]          | - [^3]                   | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x06 | [crypto]                | Handshake manager        | &#10004;      | &#10004; | &#10004; |          | &#10004; |
 | 0x07 | [new_token]             | Session manager          | &#10004;      |          |          |          | &#10004; |
 | 0x08 | [stream 0x08]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x09 | [stream 0x09]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x0A | [stream 0x0A]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x0B | [stream 0x0B]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x0C | [stream 0x0C]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x0D | [stream 0x0D]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x0E | [stream 0x0E]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x0F | [stream 0x0F]           | Apprioriate stream [^4]  | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x10 | [max_data]              | Flow control [^5]        | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x11 | [max_stream_data]       | Flow control [^5]        | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x12 | [max_streams 0x12]      | Connection manager? [^6] | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x13 | [max_streams 0x13]      | Connection manager? [^6] | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x14 | [data_blocked]          | Flow control [^5]        | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x15 | [stream_data_blocked]   | Flow control [^5]        | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x16 | [streams_blocked 0x16]  | Connection manager? [^6] | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x17 | [streams_blocked 0x17]  | Connection manager? [^6] | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x18 | [new_connection_id]     | Connection manager       | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x19 | [retire_connection_id]  | Connection manager       | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x1A | [path_challenge]        | Connection manager? [^7] | &#10004;      |          |          | &#10004; | &#10004; |
 | 0x1B | [path_response]         | Connection manager? [^7] | &#10004;      |          |          |          | &#10004; |
 | 0x1C | [connection_close 0x1C] | Connection manager       |               | &#10004; | &#10004; | &#10004; | &#10004; |
 | 0x1D | [connection_close 0x1D] | Connection manager       |               |          |          | &#10004; | &#10004; |
 | 0x1E | [handshake_done]        | Handshake manager        | &#10004;      |          |          |          | &#10004; |
 | ???? | *[Extension Frames]*    | - [^8]                   | &#10004;      |          |          |          |          |

 The I, H, 0, and 1 columns are validity in different packet types, with this meaning:

 | Pkts | Description                |
 |:----:|----------------------------|
 | I    | Valid in Initial packets   |
 | H    | Valid in Handshake packets |
 | 0    | Valid in 0-RTT packets     |
 | 1    | Valid in 1-RTT packets     |

 Notes:

 [^1]: This creates and populates an `QUIC_ACKM_ACK` structure, then calls
     `QUIC_ACKM_on_rx_ack_frame()`, with the appropriate context
     (`QUIC_ACKM`, the created `QUIC_ACKM_ACK`, `pkt_space` and `rx_time`)
 [^2]: Immediately terminates the appropriate receiving stream `QUIC_STREAM`
     object.
     This includes discarding any buffered application data.
     For a stream that's send-only, the error `STREAM_STATE_ERROR` is raised,
     and the `QUIC_CONNECTION` object is terminated.
 [^3]: Immediately terminates the appropriate sending stream `QUIC_STREAM`
     object.
     For a stream that's receive-only, the error `STREAM_STATE_ERROR` is
     raised, and the `QUIC_CONNECTION` object is terminated.
 [^4]: The frame payload (Stream Data) is passed as is to the `QUIC_STREAM`
     object, along with available metadata (offset and length, as determined
     to be available from the lower 3 bits of the frame type).
 [^5]: The details of what flow control will need are yet to be determined
 [^6]: I imagine that `max_streams` and `streams_blocked` concern a Connection
     manager before anything else.
 [^7]: I imagine that path challenge/response concerns a Connection manager
     before anything else.
 [^8]: We have no idea what extension frames there will be.  However, we
     must at least acknowledge their presence, so much is clear from the RFC.

 [overview]: https://github.com/openssl/openssl/blob/master/doc/designs/quic-design/quic-overview.md
 [TX packetizer]: https://github.com/openssl/openssl/pull/18570
 [SSL object refactoring using SSL_CONNECTION object]: https://github.com/openssl/openssl/pull/18612
 [QUIC Demuxer and Record Layer (RX+TX)]: https://github.com/openssl/openssl/pull/18949
 [ACK manager]: https://github.com/openssl/openssl/pull/18564
 [RFC 9000 12.4 Frames and Frame Types]: https://datatracker.ietf.org/doc/html/rfc9000#section-12.4
 [padding]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.1
 [ping]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.2
 [ack 0x02]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.3
 [ack 0x03]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.3
 [reset_stream]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.4
 [stop_sending]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.5
 [crypto]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.6
 [new_token]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.7
 [stream 0x08]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x09]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x0A]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x0B]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x0C]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x0D]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x0E]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [stream 0x0F]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
 [max_data]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.9
 [max_stream_data]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.10
 [max_streams 0x12]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.11
 [max_streams 0x13]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.11
 [data_blocked]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.12
 [stream_data_blocked]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.13
 [streams_blocked 0x16]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.14
 [streams_blocked 0x17]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.14
 [new_connection_id]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.15
 [retire_connection_id]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.16
 [path_challenge]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.17
 [path_response]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.18
 [connection_close 0x1C]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.19
 [connection_close 0x1D]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.19
 [handshake_done]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.20
 [Extension Frames]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.21
	RX depacketizer
	===============

	This component takes a QUIC packet and parses the frames contained therein,
	to be forwarded to appropriate other components for further processing.

	In the [overview], this is called the "RX Frame Handler". The name "RX
	depacketizer" was chosen to reflect the kinship with the [TX packetizer].

	Main structures
	---------------

	### Connection

	Represented by an `QUIC_CONNECTION` object, defined in
	[`include/internal/quic_ssl.h`](../../../include/internal/quic_ssl.h).

	### Stream

	Represented by an `QUIC_STREAM` object (yet to be defined).

	### Packets

	Represented by the `OSSL_QRX_PKT` structure, defined in
	`include/internal/quic_record_rx.h` in [QUIC Demuxer and Record Layer (RX+TX)].

	Interactions
	------------

	The RX depacketizer receives a packet from the QUIC Read Record Layer, and
	then processes frames in two phases:

	1. [Collect information for the ACK Manager](#collect-information-for-the-ack-manager)
	2. [Pass frame data](#pass-frame-data)

	### Other components

	There are a number of other components that the RX depacketizer wants to
	interact with:

	- [ACK manager]
	- Handshake manager, which is currently unspecified. It's assumed that
	this will wrap around what is called the "TLS Handshake Record Layer",
	in the [overview]
	- Session manager, which is currently unspecified for QUIC, but may very
	well be the existing `SSL_SESSION` functionality, extended to fit QUIC
	purposes.
	- Flow control, which is currently unspecified. In the [overview], it's
	called the "Flow Controller And Statistics Collector"
	- Connection manager, which is currently unspecified. In the [overview],
	there's a "Connection State Machine" that the "RX Frame Handler" isn't
	talking directly with, so it's possible that the Connection manager will
	turn out to be the Handshake manager.
	- Stream SSL objects, to pass the stream data to.

	### Read and process a packet

	Following how things are designed elsewhere, the depacketizer is assumed to
	be called "from above" using the following function:

	``` C
	__owur int ossl_quic_depacketize(QUIC_CONNECTION *connection);
	```

	This function would create an `OSSL_QRX_PKT` and call the QUIC Read Record
	Layer with a pointer to it, leaving it to the QUIC Read Record Layer to fill
	in the data.

	This uses the `ossl_qrx_read_pkt()` packet reading function from
	[QUIC Demuxer and Record Layer (RX+TX)].
	(the `OSSL_QRX_PKT` structure / sub-structure needs to be extended to take
	an `OSSL_TIME`, possibly by reference, which should be filled in with the
	packet reception time)

	### Collect information for the [ACK manager]

	This collects appropriate data into a `QUIC_ACKM_RX_PKT` structure:

	- The packet number (`packet->packet_number`)
	- The packet receive time (`received`)
	- The packet space, which is always:
	- `QUIC_PN_SPACE_INITIAL` when `packet->packet_type == pkt_initial`
	- `QUIC_PN_SPACE_HANDSHAKE` when `packet->packet_type == pkt_handshake`
	- `QUIC_PN_SPACE_APP` for all other packet types
	- The ACK eliciting flag. This is calculated by looping through all
	frames and noting those that are ACK eliciting, as determined from
	[Table 1](#table-1) below)

	### Passing frame data

	This loops through all the frames, extracts data where there is any
	and calls diverse other components as shown in the Passed to column in
	[Table 1](#table-1) below.

	#### Table 1

	Taken from [RFC 9000 12.4 Frames and Frame Types]

	\| Type \| Name \| Passed to \| ACK eliciting \| I \| H \| 0 \| 1 \|
	\|------\|-------------------------\|--------------------------\|---------------\|----------\|----------\|----------\|----------\|
	\| 0x00 \| [padding] \| - \| \| ✔ \| ✔ \| ✔ \| ✔ \|
	\| 0x01 \| [ping] \| - \| ✔ \| ✔ \| ✔ \| ✔ \| ✔ \|
	\| 0x02 \| [ack 0x02] \| [ACK manager] [^1] \| \| ✔ \| ✔ \| \| ✔ \|
	\| 0x03 \| [ack 0x03] \| [ACK manager] [^1] \| \| ✔ \| ✔ \| \| ✔ \|
	\| 0x04 \| [reset_stream] \| - [^2] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x05 \| [stop_sending] \| - [^3] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x06 \| [crypto] \| Handshake manager \| ✔ \| ✔ \| ✔ \| \| ✔ \|
	\| 0x07 \| [new_token] \| Session manager \| ✔ \| \| \| \| ✔ \|
	\| 0x08 \| [stream 0x08] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x09 \| [stream 0x09] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x0A \| [stream 0x0A] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x0B \| [stream 0x0B] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x0C \| [stream 0x0C] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x0D \| [stream 0x0D] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x0E \| [stream 0x0E] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x0F \| [stream 0x0F] \| Apprioriate stream [^4] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x10 \| [max_data] \| Flow control [^5] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x11 \| [max_stream_data] \| Flow control [^5] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x12 \| [max_streams 0x12] \| Connection manager? [^6] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x13 \| [max_streams 0x13] \| Connection manager? [^6] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x14 \| [data_blocked] \| Flow control [^5] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x15 \| [stream_data_blocked] \| Flow control [^5] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x16 \| [streams_blocked 0x16] \| Connection manager? [^6] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x17 \| [streams_blocked 0x17] \| Connection manager? [^6] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x18 \| [new_connection_id] \| Connection manager \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x19 \| [retire_connection_id] \| Connection manager \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x1A \| [path_challenge] \| Connection manager? [^7] \| ✔ \| \| \| ✔ \| ✔ \|
	\| 0x1B \| [path_response] \| Connection manager? [^7] \| ✔ \| \| \| \| ✔ \|
	\| 0x1C \| [connection_close 0x1C] \| Connection manager \| \| ✔ \| ✔ \| ✔ \| ✔ \|
	\| 0x1D \| [connection_close 0x1D] \| Connection manager \| \| \| \| ✔ \| ✔ \|
	\| 0x1E \| [handshake_done] \| Handshake manager \| ✔ \| \| \| \| ✔ \|
	\| ???? \| [Extension Frames] \| - [^8] \| ✔ \| \| \| \| \|

	The I, H, 0, and 1 columns are validity in different packet types, with this meaning:

	\| Pkts \| Description \|
	\|:----:\|----------------------------\|
	\| I \| Valid in Initial packets \|
	\| H \| Valid in Handshake packets \|
	\| 0 \| Valid in 0-RTT packets \|
	\| 1 \| Valid in 1-RTT packets \|

	Notes:

	[^1]: This creates and populates an `QUIC_ACKM_ACK` structure, then calls
	`QUIC_ACKM_on_rx_ack_frame()`, with the appropriate context
	(`QUIC_ACKM`, the created `QUIC_ACKM_ACK`, `pkt_space` and `rx_time`)
	[^2]: Immediately terminates the appropriate receiving stream `QUIC_STREAM`
	object.
	This includes discarding any buffered application data.
	For a stream that's send-only, the error `STREAM_STATE_ERROR` is raised,
	and the `QUIC_CONNECTION` object is terminated.
	[^3]: Immediately terminates the appropriate sending stream `QUIC_STREAM`
	object.
	For a stream that's receive-only, the error `STREAM_STATE_ERROR` is
	raised, and the `QUIC_CONNECTION` object is terminated.
	[^4]: The frame payload (Stream Data) is passed as is to the `QUIC_STREAM`
	object, along with available metadata (offset and length, as determined
	to be available from the lower 3 bits of the frame type).
	[^5]: The details of what flow control will need are yet to be determined
	[^6]: I imagine that `max_streams` and `streams_blocked` concern a Connection
	manager before anything else.
	[^7]: I imagine that path challenge/response concerns a Connection manager
	before anything else.
	[^8]: We have no idea what extension frames there will be. However, we
	must at least acknowledge their presence, so much is clear from the RFC.

	[overview]: https://github.com/openssl/openssl/blob/master/doc/designs/quic-design/quic-overview.md
	[TX packetizer]: https://github.com/openssl/openssl/pull/18570
	[SSL object refactoring using SSL_CONNECTION object]: https://github.com/openssl/openssl/pull/18612
	[QUIC Demuxer and Record Layer (RX+TX)]: https://github.com/openssl/openssl/pull/18949
	[ACK manager]: https://github.com/openssl/openssl/pull/18564
	[RFC 9000 12.4 Frames and Frame Types]: https://datatracker.ietf.org/doc/html/rfc9000#section-12.4
	[padding]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.1
	[ping]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.2
	[ack 0x02]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.3
	[ack 0x03]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.3
	[reset_stream]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.4
	[stop_sending]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.5
	[crypto]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.6
	[new_token]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.7
	[stream 0x08]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x09]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x0A]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x0B]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x0C]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x0D]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x0E]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[stream 0x0F]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.8
	[max_data]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.9
	[max_stream_data]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.10
	[max_streams 0x12]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.11
	[max_streams 0x13]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.11
	[data_blocked]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.12
	[stream_data_blocked]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.13
	[streams_blocked 0x16]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.14
	[streams_blocked 0x17]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.14
	[new_connection_id]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.15
	[retire_connection_id]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.16
	[path_challenge]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.17
	[path_response]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.18
	[connection_close 0x1C]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.19
	[connection_close 0x1D]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.19
	[handshake_done]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.20
	[Extension Frames]: https://datatracker.ietf.org/doc/html/rfc9000#section-19.21