219 lines
8.5 KiB
OCaml
219 lines
8.5 KiB
OCaml
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(*----------------------------------------------------------------------------
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* Copyright (c) 2019 António Nuno Monteiro
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*---------------------------------------------------------------------------*)
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let connection_preface = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
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module FrameType = struct
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type t =
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(* From RFC7540§6.1:
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* DATA frames (type=0x0) convey arbitrary, variable-length sequences
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* of octets associated with a stream. *)
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| Data
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(* From RFC7540§6.2:
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* The HEADERS frame (type=0x1) is used to open a stream (Section 5.1),
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* and additionally carries a header block fragment. *)
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| Headers
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(* From RFC7540§6.3:
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* The PRIORITY frame (type=0x2) specifies the sender-advised priority
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* of a stream (Section 5.3). *)
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| Priority
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(* From RFC7540§6.4:
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* The RST_STREAM frame (type=0x3) allows for immediate termination of
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* a stream. *)
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| RSTStream
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(* From RFC7540§6.5:
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* The SETTINGS frame (type=0x4) conveys configuration parameters that
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* affect how endpoints communicate, such as preferences and
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* constraints on peer behavior. *)
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| Settings
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(* From RFC7540§6.6:
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* The PUSH_PROMISE frame (type=0x5) is used to notify the peer
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* endpoint in advance of streams the sender intends to initiate. *)
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| PushPromise
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(* From RFC7540§6.7:
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* The PING frame (type=0x6) is a mechanism for measuring a minimal
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* round-trip time from the sender, as well as determining whether an
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* idle connection is still functional. *)
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| Ping
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(* From RFC7540§6.8:
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* The GOAWAY frame (type=0x7) is used to initiate shutdown of a
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* connection or to signal serious error conditions. *)
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| GoAway
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(* From RFC7540§6.9:
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* The WINDOW_UPDATE frame (type=0x8) is used to implement flow
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* control; [...]. *)
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| WindowUpdate
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(* From RFC7540§6.10:
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* The CONTINUATION frame (type=0x9) is used to continue a sequence of
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* header block fragments (Section 4.3). *)
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| Continuation
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(* From RFC7540§5.1:
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* Frames of unknown types are ignored. *)
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| Unknown of int
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let serialize = function
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| Data -> 0
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| Headers -> 1
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| Priority -> 2
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| RSTStream -> 3
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| Settings -> 4
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| PushPromise -> 5
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| Ping -> 6
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| GoAway -> 7
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| WindowUpdate -> 8
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| Continuation -> 9
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| Unknown x -> x
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let parse = function
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| 0 -> Data
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| 1 -> Headers
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| 2 -> Priority
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| 3 -> RSTStream
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| 4 -> Settings
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| 5 -> PushPromise
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| 6 -> Ping
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| 7 -> GoAway
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| 8 -> WindowUpdate
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| 9 -> Continuation
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| x -> Unknown x
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end
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(* From RFC7540§4.1:
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* The fields of the frame header are defined as:
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*
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* Length: The length of the frame payload expressed as an unsigned 24-bit
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* integer. [...]
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*
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* Type: The 8-bit type of the frame. [...]
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*
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* Flags: An 8-bit field reserved for boolean flags specific to the frame
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* type. [...]
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*
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* Stream Identifier: A stream identifier (see Section 5.1.1) expressed as
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* an unsigned 31-bit integer. [...] *)
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type frame_header =
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{ payload_length : int
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; flags : Flags.t
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; stream_id : Stream_identifier.t
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; frame_type : FrameType.t
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}
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(* From RFC7540§4.1:
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* The structure and content of the frame payload is dependent entirely on
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* the frame type. *)
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type frame_payload =
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(* From RFC7540§6.1:
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* The DATA frame contains the following fields:
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*
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* [...]
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*
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* Data: Application data. The amount of data is the remainder of the
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* frame payload after subtracting the length of the other fields
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* that are present. *)
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| Data of Bigstringaf.t
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(* From RFC7540§6.2:
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* The HEADERS frame payload has the following fields:
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*
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* E: A single-bit flag indicating that the stream dependency is
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* exclusive (see Section 5.3). [...]
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*
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* Stream Dependency: A 31-bit stream identifier for the stream that
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* this stream depends on (see Section 5.3). [...]
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*
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* Weight: An unsigned 8-bit integer representing a priority weight for
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* the stream (see Section 5.3). [...] This field is only
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* present if the PRIORITY flag is set.
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*
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* Header Block Fragment: A header block fragment (Section 4.3). *)
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| Headers of Priority.t * Bigstringaf.t
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(* From RFC7540§6.3:
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* The payload of a PRIORITY frame contains the following fields:
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*
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* E: A single-bit flag indicating that the stream dependency is
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* exclusive (see Section 5.3).
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*
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* Stream Dependency: A 31-bit stream identifier for the stream that this
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* stream depends on (see Section 5.3).
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*
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* Weight: An unsigned 8-bit integer representing a priority weight for
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* the stream (see Section 5.3). [...] *)
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| Priority of Priority.t
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(* From RFC7540§6.4:
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* The RST_STREAM frame contains a single unsigned, 32-bit integer
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* identifying the error code (Section 7). [...] *)
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| RSTStream of Error_code.t
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(* From RFC7540§6.5:
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* The payload of a SETTINGS frame consists of zero or more parameters,
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* each consisting of an unsigned 16-bit setting identifier and an
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* unsigned 32-bit value. *)
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| Settings of Settings.settings_list
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(* From RFC7540§6.6:
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* The PUSH_PROMISE frame includes the unsigned 31-bit identifier of the
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* stream the endpoint plans to create along with a set of headers that
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* provide additional context for the stream. *)
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| PushPromise of Stream_identifier.t * Bigstringaf.t
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(* From RFC7540§6.7:
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* In addition to the frame header, PING frames MUST contain 8 octets of
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* opaque data in the payload. A sender can include any value it chooses
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* and use those octets in any fashion. *)
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| Ping of Bigstringaf.t
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(* From RFC7540§6.8:
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* The last stream identifier in the GOAWAY frame contains the
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* highest-numbered stream identifier for which the sender of the GOAWAY
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* frame might have taken some action on or might yet take action on.
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*
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* [...] The GOAWAY frame also contains a 32-bit error code (Section 7)
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* that contains the reason for closing the connection.
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*
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* [...] Endpoints MAY append opaque data to the payload of any GOAWAY
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* frame. *)
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| GoAway of Stream_identifier.t * Error_code.t * Bigstringaf.t
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(* From RFC7540§6.9:
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* The payload of a WINDOW_UPDATE frame is one reserved bit plus an
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* unsigned 31-bit integer indicating the number of octets that the
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* sender can transmit in addition to the existing flow-control
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* window. *)
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| WindowUpdate of Settings.WindowSize.t
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(* From RFC7540§6.10:
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* The CONTINUATION frame payload contains a header block fragment
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* (Section 4.3). *)
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| Continuation of Bigstringaf.t
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| Unknown of int * Bigstringaf.t
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(* From RFC7540§4.1:
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* All frames begin with a fixed 9-octet header followed by a variable-length
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* payload. *)
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type t =
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{ frame_header : frame_header
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; frame_payload : frame_payload
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}
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