From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>

Date: Thu, 11 Jun 2015 14:04:21 +0200

Subject: [PATCH] Add cowboy_http2 with initial HTTP/2 suppport

diff --git a/src/cow_http2.erl b/src/cow_http2.erl

new file mode 100644

index 0000000..a4d2e23

--- /dev/null

+++ b/src/cow_http2.erl

@@ -0,0 +1,337 @@

+%% Copyright (c) 2015, Loïc Hoguin <essen@ninenines.eu>

+%%

+%% Permission to use, copy, modify, and/or distribute this software for any

+%% purpose with or without fee is hereby granted, provided that the above

+%% copyright notice and this permission notice appear in all copies.

+%%

+%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

+%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

+%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

+%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

+%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

+%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

+%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

+

+-module(cow_http2).

+

+%% Parsing.

+-export([parse/1]).

+

+%% Building.

+-export([data/3]).

+-export([headers/3]).

+-export([rst_stream/2]).

+-export([settings/1]).

+-export([push_promise/3]).

+-export([ping_ack/1]).

+

+-type streamid() :: pos_integer().

+-type fin() :: fin | nofin.

+-type head_fin() :: head_fin | head_nofin.

+-type exclusive() :: exclusive | shared.

+-type weight() :: 1..256.

+-type settings() :: map().

+

+-type error() :: no_error

+	| protocol_error

+	| internal_error

+	| flow_control_error

+	| settings_timeout

+	| stream_closed

+	| frame_size_error

+	| refused_stream

+	| cancel

+	| compression_error

+	| connect_error

+	| enhance_your_calm

+	| inadequate_security

+	| http_1_1_required

+	| unknown_error.

+-export_type([error/0]).

+

+-type frame() :: {data, streamid(), fin(), binary()}

+	| {headers, streamid(), fin(), head_fin(), binary()}

+	| {headers, streamid(), fin(), head_fin(), exclusive(), streamid(), weight(), binary()}

+	| {priority, streamid(), exclusive(), streamid(), weight()}

+	| {rst_stream, streamid(), error()}

+	| {settings, settings()}

+	| settings_ack

+	| {push_promise, streamid(), head_fin(), streamid(), binary()}

+	| {ping, integer()}

+	| {ping_ack, integer()}

+	| {goaway, streamid(), error(), binary()}

+	| {window_update, non_neg_integer()}

+	| {window_update, streamid(), non_neg_integer()}

+	| {continuation, streamid(), head_fin(), binary()}.

+-export_type([frame/0]).

+

+%% Parsing.

+

+%%

+%% DATA frames.

+%%

+parse(<< _:24, 0:8, _:9, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'DATA frames MUST be associated with a stream. (RFC7540 6.1)'};

+parse(<< Len0:24, 0:8, _:4, 1:1, _:35, PadLen:8, _/bits >>) when PadLen >= Len0 ->

+	{connection_error, protocol_error, 'Length of padding MUST be less than length of payload. (RFC7540 6.1)'};

+%% No padding.

+parse(<< Len:24, 0:8, _:4, 0:1, _:2, FlagEndStream:1, _:1, StreamID:31, Data:Len/binary, Rest/bits >>) ->

+	{ok, {data, StreamID, parse_fin(FlagEndStream), Data}, Rest};

+%% Padding.

+parse(<< Len0:24, 0:8, _:4, 1:1, _:2, FlagEndStream:1, _:1, StreamID:31, PadLen:8, Rest0/bits >>)

+		when byte_size(Rest0) >= Len0 - 1 ->

+	Len = Len0 - PadLen,

+	case Rest0 of

+		<< Data:Len/binary, 0:PadLen/binary, Rest/bits >> ->

+			{ok, {data, StreamID, parse_fin(FlagEndStream), Data}, Rest};

+		_ ->

+			{connection_error, protocol_error, 'Padding octets MUST be set to zero. (RFC7540 6.1)'}

+	end;

+%%

+%% HEADERS frames.

+%%

+parse(<< _:24, 1:8, _:9, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'HEADERS frames MUST be associated with a stream. (RFC7540 6.2)'};

+parse(<< Len0:24, 1:8, _:4, 1:1, _:35, PadLen:8, _/bits >>) when PadLen >= Len0 ->

+	{connection_error, protocol_error, 'Length of padding MUST be less than length of payload. (RFC7540 6.2)'};

+parse(<< Len0:24, 1:8, _:2, 1:1, _:1, 1:1, _:35, PadLen:8, _/bits >>) when PadLen >= Len0 - 5 ->

+	{connection_error, protocol_error, 'Length of padding MUST be less than length of payload. (RFC7540 6.2)'};

+%% No padding, no priority.

+parse(<< Len:24, 1:8, _:2, 0:1, _:1, 0:1, FlagEndHeaders:1, _:1, FlagEndStream:1, _:1, StreamID:31,

+		HeaderBlockFragment:Len/binary, Rest/bits >>) ->

+	{ok, {headers, StreamID, parse_fin(FlagEndStream), parse_head_fin(FlagEndHeaders), HeaderBlockFragment}, Rest};

+%% Padding, no priority.

+parse(<< Len0:24, 1:8, _:2, 0:1, _:1, 1:1, FlagEndHeaders:1, _:1, FlagEndStream:1, _:1, StreamID:31,

+		PadLen:8, Rest0/bits >>) when byte_size(Rest0) >= Len0 - 1 ->

+	Len = Len0 - PadLen - 1,

+	case Rest0 of

+		<< HeaderBlockFragment:Len/binary, 0:PadLen/binary, Rest/bits >> ->

+			{ok, {headers, StreamID, parse_fin(FlagEndStream), parse_head_fin(FlagEndHeaders), HeaderBlockFragment}, Rest};

+		_ ->

+			{connection_error, protocol_error, 'Padding octets MUST be set to zero. (RFC7540 6.2)'}

+	end;

+%% No padding, priority.

+parse(<< Len0:24, 1:8, _:2, 1:1, _:1, 0:1, FlagEndHeaders:1, _:1, FlagEndStream:1, _:1, StreamID:31,

+		E:1, DepStreamID:31, Weight:8, Rest0/bits >>) when byte_size(Rest0) >= Len0 - 5 ->

+	Len = Len0 - 5,

+	<< HeaderBlockFragment:Len/binary, Rest/bits >> = Rest0,

+	{ok, {headers, StreamID, parse_fin(FlagEndStream), parse_head_fin(FlagEndHeaders),

+		parse_exclusive(E), DepStreamID, Weight + 1, HeaderBlockFragment}, Rest};

+%% Padding, priority.

+parse(<< Len0:24, 1:8, _:2, 1:1, _:1, 1:1, FlagEndHeaders:1, _:1, FlagEndStream:1, _:1, StreamID:31,

+		PadLen:8, E:1, DepStreamID:31, Weight:8, Rest0/bits >>) when byte_size(Rest0) >= Len0 - 6 ->

+	Len = Len0 - PadLen - 6,

+	case Rest0 of

+		<< HeaderBlockFragment:Len/binary, 0:PadLen/binary, Rest/bits >> ->

+			{ok, {headers, StreamID, parse_fin(FlagEndStream), parse_head_fin(FlagEndHeaders),

+				parse_exclusive(E), DepStreamID, Weight + 1, HeaderBlockFragment}, Rest};

+		_ ->

+			{connection_error, protocol_error, 'Padding octets MUST be set to zero. (RFC7540 6.2)'}

+	end;

+%%

+%% PRIORITY frames.

+%%

+parse(<< 5:24, 2:8, _:9, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'PRIORITY frames MUST be associated with a stream. (RFC7540 6.3)'};

+parse(<< 5:24, 2:8, _:9, StreamID:31, E:1, DepStreamID:31, Weight:8, Rest/bits >>) ->

+	{ok, {priority, StreamID, parse_exclusive(E), DepStreamID, Weight + 1}, Rest};

+%% @todo figure out how to best deal with frame size errors; if we have everything fine

+%% if not we might want to inform the caller how much he should expect so that it can

+%% decide if it should just close the connection

+parse(<< BadLen:24, 2:8, _:9, StreamID:31, _:BadLen/binary, Rest/bits >>) ->

+	{stream_error, StreamID, frame_size_error, 'PRIORITY frames MUST be 5 bytes wide. (RFC7540 6.3)', Rest};

+%%

+%% RST_STREAM frames.

+%%

+parse(<< 4:24, 3:8, _:9, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'RST_STREAM frames MUST be associated with a stream. (RFC7540 6.4)'};

+parse(<< 4:24, 3:8, _:9, StreamID:31, ErrorCode:32, Rest/bits >>) ->

+	{ok, {rst_stream, StreamID, parse_error_code(ErrorCode)}, Rest};

+%% @todo same as priority

+parse(<< BadLen:24, 3:8, _:9, StreamID:31, _:BadLen/binary, Rest/bits >>) ->

+	{stream_error, StreamID, frame_size_error, 'RST_STREAM frames MUST be 4 bytes wide. (RFC7540 6.4)', Rest};

+%%

+%% SETTINGS frames.

+%%

+parse(<< 0:24, 4:8, _:7, 1:1, _:1, 0:31, Rest/bits >>) ->

+	{ok, settings_ack, Rest};

+parse(<< _:24, 4:8, _:7, 1:1, _:1, 0:31, _/bits >>) ->

+	{connection_error, frame_size_error, 'SETTINGS frames with the ACK flag set MUST have a length of 0. (RFC7540 6.5)'};

+parse(<< Len:24, 4:8, _:7, 0:1, _:1, 0:31, _/bits >>) when Len rem 6 =/= 0 ->

+	{connection_error, frame_size_error, 'SETTINGS frames MUST have a length multiple of 6. (RFC7540 6.5)'};

+parse(<< Len:24, 4:8, _:7, 0:1, _:1, 0:31, Rest/bits >>) when byte_size(Rest) >= Len ->

+	parse_settings(Rest, Len, #{});

+parse(<< _:24, 4:8, _/bits >>) ->

+	{connection_error, protocol_error, 'SETTINGS frames MUST NOT be associated with a stream. (RFC7540 6.5)'};

+%%

+%% PUSH_PROMISE frames.

+%%

+parse(<< _:24, 5:8, _:9, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'PUSH_PROMISE frames MUST be associated with a stream. (RFC7540 6.6)'};

+parse(<< Len0:24, 5:8, _:4, 0:1, FlagEndHeaders:1, _:3, StreamID:31, _:1, PromisedStreamID:31, Rest0/bits >>)

+		when byte_size(Rest0) >= Len0 - 4 ->

+	Len = Len0 - 4,

+	<< HeaderBlockFragment:Len/binary, Rest/bits >> = Rest0,

+	{ok, {push_promise, StreamID, parse_head_fin(FlagEndHeaders), PromisedStreamID, HeaderBlockFragment}, Rest};

+parse(<< Len0:24, 5:8, _:4, 1:1, FlagEndHeaders:1, _:2, StreamID:31, PadLen:8, _:1, PromisedStreamID:31, Rest0/bits >>)

+		when byte_size(Rest0) >= Len0 - 5 ->

+	Len = Len0 - 5,

+	case Rest0 of

+		<< HeaderBlockFragment:Len/binary, 0:PadLen/binary, Rest/bits >> ->

+			{ok, {push_promise, StreamID, parse_head_fin(FlagEndHeaders), PromisedStreamID, HeaderBlockFragment}, Rest};

+		_ ->

+			{connection_error, protocol_error, 'Padding octets MUST be set to zero. (RFC7540 6.6)'}

+	end;

+%%

+%% PING frames.

+%%

+parse(<< 8:24, 6:8, _:7, 1:1, _:1, 0:31, Opaque:64, Rest/bits >>) ->

+	{ok, {ping_ack, Opaque}, Rest};

+parse(<< 8:24, 6:8, _:7, 0:1, _:1, 0:31, Opaque:64, Rest/bits >>) ->

+	{ok, {ping, Opaque}, Rest};

+parse(<< 8:24, 6:8, _:104, _/bits >>) ->

+	{connection_error, protocol_error, 'PING frames MUST NOT be associated with a stream. (RFC7540 6.7)'};

+parse(<< _:24, 6:8, _/bits >>) ->

+	{connection_error, frame_size_error, 'PING frames MUST be 8 bytes wide. (RFC7540 6.7)'};

+%%

+%% GOAWAY frames.

+%%

+parse(<< Len0:24, 7:8, _:9, 0:31, _:1, LastStreamID:31, ErrorCode:32, Rest0/bits >>) when byte_size(Rest0) >= Len0 - 8 ->

+	Len = Len0 - 8,

+	<< DebugData:Len/binary, Rest/bits >> = Rest0,

+	{ok, {goaway, LastStreamID, parse_error_code(ErrorCode), DebugData}, Rest};

+parse(<< _:24, 7:8, _:40, _/bits >>) ->

+	{connection_error, protocol_error, 'GOAWAY frames MUST NOT be associated with a stream. (RFC7540 6.8)'};

+%%

+%% WINDOW_UPDATE frames.

+%%

+parse(<< 4:24, 8:8, _:9, 0:31, _:1, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'WINDOW_UPDATE frames MUST have a non-zero increment. (RFC7540 6.9)'};

+parse(<< 4:24, 8:8, _:9, 0:31, _:1, Increment:31, Rest/bits >>) ->

+	{ok, {window_update, Increment}, Rest};

+parse(<< 4:24, 8:8, _:9, StreamID:31, _:1, 0:31, _/bits >>) ->

+	{stream_error, StreamID, protocol_error, 'WINDOW_UPDATE frames MUST have a non-zero increment. (RFC7540 6.9)'};

+parse(<< 4:24, 8:8, _:9, StreamID:31, _:1, Increment:31, Rest/bits >>) ->

+	{ok, {window_update, StreamID, Increment}, Rest};

+parse(<< _:24, 8:8, _/bits >>) ->

+	{connection_error, frame_size_error, 'WINDOW_UPDATE frames MUST be 4 bytes wide. (RFC7540 6.9)'};

+%%

+%% CONTINUATION frames.

+%%

+parse(<< _:24, 9:8, _:9, 0:31, _/bits >>) ->

+	{connection_error, protocol_error, 'CONTINUATION frames MUST be associated with a stream. (RFC7540 6.10)'};

+parse(<< Len:24, 9:8, _:5, FlagEndHeaders:1, _:3, StreamID:31, HeaderBlockFragment:Len/binary, Rest/bits >>) ->

+	{ok, {continuation, StreamID, parse_head_fin(FlagEndHeaders), HeaderBlockFragment}, Rest};

+%%

+%% Incomplete frames.

+%%

+parse(_) ->

+	more.

+

+parse_fin(0) -> nofin;

+parse_fin(1) -> fin.

+

+parse_head_fin(0) -> head_nofin;

+parse_head_fin(1) -> head_fin.

+

+parse_exclusive(0) -> shared;

+parse_exclusive(1) -> exclusive.

+

+parse_error_code( 0) -> no_error;

+parse_error_code( 1) -> protocol_error;

+parse_error_code( 2) -> internal_error;

+parse_error_code( 3) -> flow_control_error;

+parse_error_code( 4) -> settings_timeout;

+parse_error_code( 5) -> stream_closed;

+parse_error_code( 6) -> frame_size_error;

+parse_error_code( 7) -> refused_stream;

+parse_error_code( 8) -> cancel;

+parse_error_code( 9) -> compression_error;

+parse_error_code(10) -> connect_error;

+parse_error_code(11) -> enhance_your_calm;

+parse_error_code(12) -> inadequate_security;

+parse_error_code(13) -> http_1_1_required;

+parse_error_code(_) -> unknown_error.

+

+parse_settings(Rest, 0, Settings) ->

+	{ok, {settings, Settings}, Rest};

+%% SETTINGS_HEADER_TABLE_SIZE.

+parse_settings(<< 1:16, Value:32, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings#{header_table_size => Value});

+%% SETTINGS_ENABLE_PUSH.

+parse_settings(<< 2:16, 0:32, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings#{enable_push => false});

+parse_settings(<< 2:16, 1:32, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings#{enable_push => true});

+parse_settings(<< 2:16, _:32, _/bits >>, _, _) ->

+	{connection_error, protocol_error, 'The SETTINGS_ENABLE_PUSH value MUST be 0 or 1. (RFC7540 6.5.2)'};

+%% SETTINGS_MAX_CONCURRENT_STREAMS.

+parse_settings(<< 3:16, Value:32, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings#{max_concurrent_streams => Value});

+%% SETTINGS_INITIAL_WINDOW_SIZE.

+parse_settings(<< 4:16, Value:32, _/bits >>, _, _) when Value > 16#7fffffff ->

+	{connection_error, flow_control_error, 'The maximum SETTINGS_INITIAL_WINDOW_SIZE value is 0x7fffffff. (RFC7540 6.5.2)'};

+parse_settings(<< 4:16, Value:32, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings#{initial_window_size => Value});

+%% SETTINGS_MAX_FRAME_SIZE.

+parse_settings(<< 5:16, Value:32, _/bits >>, _, _) when Value =< 16#3fff ->

+	{connection_error, protocol_error, 'The SETTINGS_MAX_FRAME_SIZE value must be > 0x3fff. (RFC7540 6.5.2)'};

+parse_settings(<< 5:16, Value:32, Rest/bits >>, Len, Settings) when Value =< 16#ffffff ->

+	parse_settings(Rest, Len - 6, Settings#{max_frame_size => Value});

+parse_settings(<< 5:16, _:32, _/bits >>, _, _) ->

+	{connection_error, protocol_error, 'The SETTINGS_MAX_FRAME_SIZE value must be =< 0xffffff. (RFC7540 6.5.2)'};

+%% SETTINGS_MAX_HEADER_LIST_SIZE.

+parse_settings(<< 6:16, Value:32, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings#{max_header_list_size => Value});

+parse_settings(<< _:48, Rest/bits >>, Len, Settings) ->

+	parse_settings(Rest, Len - 6, Settings).

+

+%% Building.

+

+%% @todo Check size and create multiple frames if needed.

+data(StreamID, IsFin, Data) ->

+	Len = iolist_size(Data),

+	FlagEndStream = flag_fin(IsFin),

+	[<< Len:24, 0:15, FlagEndStream:1, 0:1, StreamID:31 >>, Data].

+

+%% @todo Check size of HeaderBlock and use CONTINUATION frames if needed.

+headers(StreamID, IsFin, HeaderBlock) ->

+	Len = iolist_size(HeaderBlock),

+	FlagEndStream = flag_fin(IsFin),

+	FlagEndHeaders = 1,

+	[<< Len:24, 1:8, 0:5, FlagEndHeaders:1, 0:1, FlagEndStream:1, 0:1, StreamID:31 >>, HeaderBlock].

+

+rst_stream(StreamID, Reason) ->

+	ErrorCode = error_code(Reason),

+	<< 4:24, 3:8, 0:9, StreamID:31, ErrorCode:32 >>.

+

+%% @todo Actually implement it. :-)

+settings(#{}) ->

+	<< 0:24, 4:8, 0:40 >>.

+

+%% @todo Check size of HeaderBlock and use CONTINUATION frames if needed.

+push_promise(StreamID, PromisedStreamID, HeaderBlock) ->

+	Len = iolist_size(HeaderBlock) + 4,

+	FlagEndHeaders = 1,

+	[<< Len:24, 5:8, 0:5, FlagEndHeaders:1, 0:3, StreamID:31, 0:1, PromisedStreamID:31 >>, HeaderBlock].

+

+ping_ack(Opaque) ->

+	<< 8:24, 6:8, 0:7, 1:1, 0:32, Opaque:64 >>.

+

+flag_fin(nofin) -> 0;

+flag_fin(fin) -> 1.

+

+error_code(no_error) -> 0;

+error_code(protocol_error) -> 1;

+error_code(internal_error) -> 2;

+error_code(flow_control_error) -> 3;

+error_code(settings_timeout) -> 4;

+error_code(stream_closed) -> 5;

+error_code(frame_size_error) -> 6;

+error_code(refused_stream) -> 7;

+error_code(cancel) -> 8;

+error_code(compression_error) -> 9;

+error_code(connect_error) -> 10;

+error_code(enhance_your_calm) -> 11;

+error_code(inadequate_security) -> 12;

+error_code(http_1_1_required) -> 13.