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| -rw-r--r-- | src/cow_http2.erl | 337 |
1 files changed, 337 insertions, 0 deletions
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 <[email protected]> +%% +%% 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. |