From 8071eae6b92f00f001af7eef89ee6ac129e45af6 Mon Sep 17 00:00:00 2001 From: Willy Tarreau Date: Fri, 19 May 2017 18:14:51 +0200 Subject: [PATCH] CONTRIB: hpack: implement a reverse huffman table generator for hpack This one was built by studying the HPACK Huffman table (RFC7541 appendix B). It creates 5 small tables (4*512 bytes, 1*64 bytes) to map one byte at a time from the input stream based on the following observations : * rht_bit31_24[256] is indexed on bits 31..24 when < 0xfe * rht_bit24_17[256] is indexed on bits 24..17 when 31..24 >= 0xfe * rht_bit15_11_fe[32] is indexed on bits 15..11 when 24..17 == 0xfe * rht_bit15_8[256] is indexed on bits 15..8 when 24..17 == 0xff * rht_bit11_4[256] is indexed on bits 11..4 when 15..8 == 0xff * when 11..4 == 0xff, 3..2 provide the following mapping : * 00 => 0x0a, 01 => 0x0d, 10 => 0x16, 11 => EOS --- contrib/hpack/Makefile | 9 + contrib/hpack/gen-rht.c | 369 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 378 insertions(+) create mode 100644 contrib/hpack/Makefile create mode 100644 contrib/hpack/gen-rht.c diff --git a/contrib/hpack/Makefile b/contrib/hpack/Makefile new file mode 100644 index 0000000000..1ecc4e482e --- /dev/null +++ b/contrib/hpack/Makefile @@ -0,0 +1,9 @@ +CFLAGS = -O2 -W -Wall -Wextra -g +OBJS = gen-rht + +all: $(OBJS) + +%: %.c + +clean: + -rm -vf $(OBJS) *.o *.a *~ diff --git a/contrib/hpack/gen-rht.c b/contrib/hpack/gen-rht.c new file mode 100644 index 0000000000..b1b9031725 --- /dev/null +++ b/contrib/hpack/gen-rht.c @@ -0,0 +1,369 @@ +/* Reverse Huffman table generator for HPACK decoder - 2017-05-19 Willy Tarreau + * + * rht_bit31_24[256] is indexed on bits 31..24 when < 0xfe + * rht_bit24_17[256] is indexed on bits 24..17 when 31..24 >= 0xfe + * rht_bit15_11_fe[32] is indexed on bits 15..11 when 24..17 == 0xfe + * rht_bit15_8[256] is indexed on bits 15..8 when 24..17 == 0xff + * rht_bit11_4[256] is indexed on bits 11..4 when 15..8 == 0xff + * when 11..4 == 0xff, 3..2 provide the following mapping : + * 00 => 0x0a, 01 => 0x0d, 10 => 0x16, 11 => EOS + */ + +#include +#include +#include +#include + +/* from RFC7541 Appendix B */ +static const struct huff { + uint32_t c; /* code point */ + int b; /* bits */ +} ht[257] = { + [0] = { .c = 0x00001ff8, .b = 13 }, + [1] = { .c = 0x007fffd8, .b = 23 }, + [2] = { .c = 0x0fffffe2, .b = 28 }, + [3] = { .c = 0x0fffffe3, .b = 28 }, + [4] = { .c = 0x0fffffe4, .b = 28 }, + [5] = { .c = 0x0fffffe5, .b = 28 }, + [6] = { .c = 0x0fffffe6, .b = 28 }, + [7] = { .c = 0x0fffffe7, .b = 28 }, + [8] = { .c = 0x0fffffe8, .b = 28 }, + [9] = { .c = 0x00ffffea, .b = 24 }, + [10] = { .c = 0x3ffffffc, .b = 30 }, + [11] = { .c = 0x0fffffe9, .b = 28 }, + [12] = { .c = 0x0fffffea, .b = 28 }, + [13] = { .c = 0x3ffffffd, .b = 30 }, + [14] = { .c = 0x0fffffeb, .b = 28 }, + [15] = { .c = 0x0fffffec, .b = 28 }, + [16] = { .c = 0x0fffffed, .b = 28 }, + [17] = { .c = 0x0fffffee, .b = 28 }, + [18] = { .c = 0x0fffffef, .b = 28 }, + [19] = { .c = 0x0ffffff0, .b = 28 }, + [20] = { .c = 0x0ffffff1, .b = 28 }, + [21] = { .c = 0x0ffffff2, .b = 28 }, + [22] = { .c = 0x3ffffffe, .b = 30 }, + [23] = { .c = 0x0ffffff3, .b = 28 }, + [24] = { .c = 0x0ffffff4, .b = 28 }, + [25] = { .c = 0x0ffffff5, .b = 28 }, + [26] = { .c = 0x0ffffff6, .b = 28 }, + [27] = { .c = 0x0ffffff7, .b = 28 }, + [28] = { .c = 0x0ffffff8, .b = 28 }, + [29] = { .c = 0x0ffffff9, .b = 28 }, + [30] = { .c = 0x0ffffffa, .b = 28 }, + [31] = { .c = 0x0ffffffb, .b = 28 }, + [32] = { .c = 0x00000014, .b = 6 }, + [33] = { .c = 0x000003f8, .b = 10 }, + [34] = { .c = 0x000003f9, .b = 10 }, + [35] = { .c = 0x00000ffa, .b = 12 }, + [36] = { .c = 0x00001ff9, .b = 13 }, + [37] = { .c = 0x00000015, .b = 6 }, + [38] = { .c = 0x000000f8, .b = 8 }, + [39] = { .c = 0x000007fa, .b = 11 }, + [40] = { .c = 0x000003fa, .b = 10 }, + [41] = { .c = 0x000003fb, .b = 10 }, + [42] = { .c = 0x000000f9, .b = 8 }, + [43] = { .c = 0x000007fb, .b = 11 }, + [44] = { .c = 0x000000fa, .b = 8 }, + [45] = { .c = 0x00000016, .b = 6 }, + [46] = { .c = 0x00000017, .b = 6 }, + [47] = { .c = 0x00000018, .b = 6 }, + [48] = { .c = 0x00000000, .b = 5 }, + [49] = { .c = 0x00000001, .b = 5 }, + [50] = { .c = 0x00000002, .b = 5 }, + [51] = { .c = 0x00000019, .b = 6 }, + [52] = { .c = 0x0000001a, .b = 6 }, + [53] = { .c = 0x0000001b, .b = 6 }, + [54] = { .c = 0x0000001c, .b = 6 }, + [55] = { .c = 0x0000001d, .b = 6 }, + [56] = { .c = 0x0000001e, .b = 6 }, + [57] = { .c = 0x0000001f, .b = 6 }, + [58] = { .c = 0x0000005c, .b = 7 }, + [59] = { .c = 0x000000fb, .b = 8 }, + [60] = { .c = 0x00007ffc, .b = 15 }, + [61] = { .c = 0x00000020, .b = 6 }, + [62] = { .c = 0x00000ffb, .b = 12 }, + [63] = { .c = 0x000003fc, .b = 10 }, + [64] = { .c = 0x00001ffa, .b = 13 }, + [65] = { .c = 0x00000021, .b = 6 }, + [66] = { .c = 0x0000005d, .b = 7 }, + [67] = { .c = 0x0000005e, .b = 7 }, + [68] = { .c = 0x0000005f, .b = 7 }, + [69] = { .c = 0x00000060, .b = 7 }, + [70] = { .c = 0x00000061, .b = 7 }, + [71] = { .c = 0x00000062, .b = 7 }, + [72] = { .c = 0x00000063, .b = 7 }, + [73] = { .c = 0x00000064, .b = 7 }, + [74] = { .c = 0x00000065, .b = 7 }, + [75] = { .c = 0x00000066, .b = 7 }, + [76] = { .c = 0x00000067, .b = 7 }, + [77] = { .c = 0x00000068, .b = 7 }, + [78] = { .c = 0x00000069, .b = 7 }, + [79] = { .c = 0x0000006a, .b = 7 }, + [80] = { .c = 0x0000006b, .b = 7 }, + [81] = { .c = 0x0000006c, .b = 7 }, + [82] = { .c = 0x0000006d, .b = 7 }, + [83] = { .c = 0x0000006e, .b = 7 }, + [84] = { .c = 0x0000006f, .b = 7 }, + [85] = { .c = 0x00000070, .b = 7 }, + [86] = { .c = 0x00000071, .b = 7 }, + [87] = { .c = 0x00000072, .b = 7 }, + [88] = { .c = 0x000000fc, .b = 8 }, + [89] = { .c = 0x00000073, .b = 7 }, + [90] = { .c = 0x000000fd, .b = 8 }, + [91] = { .c = 0x00001ffb, .b = 13 }, + [92] = { .c = 0x0007fff0, .b = 19 }, + [93] = { .c = 0x00001ffc, .b = 13 }, + [94] = { .c = 0x00003ffc, .b = 14 }, + [95] = { .c = 0x00000022, .b = 6 }, + [96] = { .c = 0x00007ffd, .b = 15 }, + [97] = { .c = 0x00000003, .b = 5 }, + [98] = { .c = 0x00000023, .b = 6 }, + [99] = { .c = 0x00000004, .b = 5 }, + [100] = { .c = 0x00000024, .b = 6 }, + [101] = { .c = 0x00000005, .b = 5 }, + [102] = { .c = 0x00000025, .b = 6 }, + [103] = { .c = 0x00000026, .b = 6 }, + [104] = { .c = 0x00000027, .b = 6 }, + [105] = { .c = 0x00000006, .b = 5 }, + [106] = { .c = 0x00000074, .b = 7 }, + [107] = { .c = 0x00000075, .b = 7 }, + [108] = { .c = 0x00000028, .b = 6 }, + [109] = { .c = 0x00000029, .b = 6 }, + [110] = { .c = 0x0000002a, .b = 6 }, + [111] = { .c = 0x00000007, .b = 5 }, + [112] = { .c = 0x0000002b, .b = 6 }, + [113] = { .c = 0x00000076, .b = 7 }, + [114] = { .c = 0x0000002c, .b = 6 }, + [115] = { .c = 0x00000008, .b = 5 }, + [116] = { .c = 0x00000009, .b = 5 }, + [117] = { .c = 0x0000002d, .b = 6 }, + [118] = { .c = 0x00000077, .b = 7 }, + [119] = { .c = 0x00000078, .b = 7 }, + [120] = { .c = 0x00000079, .b = 7 }, + [121] = { .c = 0x0000007a, .b = 7 }, + [122] = { .c = 0x0000007b, .b = 7 }, + [123] = { .c = 0x00007ffe, .b = 15 }, + [124] = { .c = 0x000007fc, .b = 11 }, + [125] = { .c = 0x00003ffd, .b = 14 }, + [126] = { .c = 0x00001ffd, .b = 13 }, + [127] = { .c = 0x0ffffffc, .b = 28 }, + [128] = { .c = 0x000fffe6, .b = 20 }, + [129] = { .c = 0x003fffd2, .b = 22 }, + [130] = { .c = 0x000fffe7, .b = 20 }, + [131] = { .c = 0x000fffe8, .b = 20 }, + [132] = { .c = 0x003fffd3, .b = 22 }, + [133] = { .c = 0x003fffd4, .b = 22 }, + [134] = { .c = 0x003fffd5, .b = 22 }, + [135] = { .c = 0x007fffd9, .b = 23 }, + [136] = { .c = 0x003fffd6, .b = 22 }, + [137] = { .c = 0x007fffda, .b = 23 }, + [138] = { .c = 0x007fffdb, .b = 23 }, + [139] = { .c = 0x007fffdc, .b = 23 }, + [140] = { .c = 0x007fffdd, .b = 23 }, + [141] = { .c = 0x007fffde, .b = 23 }, + [142] = { .c = 0x00ffffeb, .b = 24 }, + [143] = { .c = 0x007fffdf, .b = 23 }, + [144] = { .c = 0x00ffffec, .b = 24 }, + [145] = { .c = 0x00ffffed, .b = 24 }, + [146] = { .c = 0x003fffd7, .b = 22 }, + [147] = { .c = 0x007fffe0, .b = 23 }, + [148] = { .c = 0x00ffffee, .b = 24 }, + [149] = { .c = 0x007fffe1, .b = 23 }, + [150] = { .c = 0x007fffe2, .b = 23 }, + [151] = { .c = 0x007fffe3, .b = 23 }, + [152] = { .c = 0x007fffe4, .b = 23 }, + [153] = { .c = 0x001fffdc, .b = 21 }, + [154] = { .c = 0x003fffd8, .b = 22 }, + [155] = { .c = 0x007fffe5, .b = 23 }, + [156] = { .c = 0x003fffd9, .b = 22 }, + [157] = { .c = 0x007fffe6, .b = 23 }, + [158] = { .c = 0x007fffe7, .b = 23 }, + [159] = { .c = 0x00ffffef, .b = 24 }, + [160] = { .c = 0x003fffda, .b = 22 }, + [161] = { .c = 0x001fffdd, .b = 21 }, + [162] = { .c = 0x000fffe9, .b = 20 }, + [163] = { .c = 0x003fffdb, .b = 22 }, + [164] = { .c = 0x003fffdc, .b = 22 }, + [165] = { .c = 0x007fffe8, .b = 23 }, + [166] = { .c = 0x007fffe9, .b = 23 }, + [167] = { .c = 0x001fffde, .b = 21 }, + [168] = { .c = 0x007fffea, .b = 23 }, + [169] = { .c = 0x003fffdd, .b = 22 }, + [170] = { .c = 0x003fffde, .b = 22 }, + [171] = { .c = 0x00fffff0, .b = 24 }, + [172] = { .c = 0x001fffdf, .b = 21 }, + [173] = { .c = 0x003fffdf, .b = 22 }, + [174] = { .c = 0x007fffeb, .b = 23 }, + [175] = { .c = 0x007fffec, .b = 23 }, + [176] = { .c = 0x001fffe0, .b = 21 }, + [177] = { .c = 0x001fffe1, .b = 21 }, + [178] = { .c = 0x003fffe0, .b = 22 }, + [179] = { .c = 0x001fffe2, .b = 21 }, + [180] = { .c = 0x007fffed, .b = 23 }, + [181] = { .c = 0x003fffe1, .b = 22 }, + [182] = { .c = 0x007fffee, .b = 23 }, + [183] = { .c = 0x007fffef, .b = 23 }, + [184] = { .c = 0x000fffea, .b = 20 }, + [185] = { .c = 0x003fffe2, .b = 22 }, + [186] = { .c = 0x003fffe3, .b = 22 }, + [187] = { .c = 0x003fffe4, .b = 22 }, + [188] = { .c = 0x007ffff0, .b = 23 }, + [189] = { .c = 0x003fffe5, .b = 22 }, + [190] = { .c = 0x003fffe6, .b = 22 }, + [191] = { .c = 0x007ffff1, .b = 23 }, + [192] = { .c = 0x03ffffe0, .b = 26 }, + [193] = { .c = 0x03ffffe1, .b = 26 }, + [194] = { .c = 0x000fffeb, .b = 20 }, + [195] = { .c = 0x0007fff1, .b = 19 }, + [196] = { .c = 0x003fffe7, .b = 22 }, + [197] = { .c = 0x007ffff2, .b = 23 }, + [198] = { .c = 0x003fffe8, .b = 22 }, + [199] = { .c = 0x01ffffec, .b = 25 }, + [200] = { .c = 0x03ffffe2, .b = 26 }, + [201] = { .c = 0x03ffffe3, .b = 26 }, + [202] = { .c = 0x03ffffe4, .b = 26 }, + [203] = { .c = 0x07ffffde, .b = 27 }, + [204] = { .c = 0x07ffffdf, .b = 27 }, + [205] = { .c = 0x03ffffe5, .b = 26 }, + [206] = { .c = 0x00fffff1, .b = 24 }, + [207] = { .c = 0x01ffffed, .b = 25 }, + [208] = { .c = 0x0007fff2, .b = 19 }, + [209] = { .c = 0x001fffe3, .b = 21 }, + [210] = { .c = 0x03ffffe6, .b = 26 }, + [211] = { .c = 0x07ffffe0, .b = 27 }, + [212] = { .c = 0x07ffffe1, .b = 27 }, + [213] = { .c = 0x03ffffe7, .b = 26 }, + [214] = { .c = 0x07ffffe2, .b = 27 }, + [215] = { .c = 0x00fffff2, .b = 24 }, + [216] = { .c = 0x001fffe4, .b = 21 }, + [217] = { .c = 0x001fffe5, .b = 21 }, + [218] = { .c = 0x03ffffe8, .b = 26 }, + [219] = { .c = 0x03ffffe9, .b = 26 }, + [220] = { .c = 0x0ffffffd, .b = 28 }, + [221] = { .c = 0x07ffffe3, .b = 27 }, + [222] = { .c = 0x07ffffe4, .b = 27 }, + [223] = { .c = 0x07ffffe5, .b = 27 }, + [224] = { .c = 0x000fffec, .b = 20 }, + [225] = { .c = 0x00fffff3, .b = 24 }, + [226] = { .c = 0x000fffed, .b = 20 }, + [227] = { .c = 0x001fffe6, .b = 21 }, + [228] = { .c = 0x003fffe9, .b = 22 }, + [229] = { .c = 0x001fffe7, .b = 21 }, + [230] = { .c = 0x001fffe8, .b = 21 }, + [231] = { .c = 0x007ffff3, .b = 23 }, + [232] = { .c = 0x003fffea, .b = 22 }, + [233] = { .c = 0x003fffeb, .b = 22 }, + [234] = { .c = 0x01ffffee, .b = 25 }, + [235] = { .c = 0x01ffffef, .b = 25 }, + [236] = { .c = 0x00fffff4, .b = 24 }, + [237] = { .c = 0x00fffff5, .b = 24 }, + [238] = { .c = 0x03ffffea, .b = 26 }, + [239] = { .c = 0x007ffff4, .b = 23 }, + [240] = { .c = 0x03ffffeb, .b = 26 }, + [241] = { .c = 0x07ffffe6, .b = 27 }, + [242] = { .c = 0x03ffffec, .b = 26 }, + [243] = { .c = 0x03ffffed, .b = 26 }, + [244] = { .c = 0x07ffffe7, .b = 27 }, + [245] = { .c = 0x07ffffe8, .b = 27 }, + [246] = { .c = 0x07ffffe9, .b = 27 }, + [247] = { .c = 0x07ffffea, .b = 27 }, + [248] = { .c = 0x07ffffeb, .b = 27 }, + [249] = { .c = 0x0ffffffe, .b = 28 }, + [250] = { .c = 0x07ffffec, .b = 27 }, + [251] = { .c = 0x07ffffed, .b = 27 }, + [252] = { .c = 0x07ffffee, .b = 27 }, + [253] = { .c = 0x07ffffef, .b = 27 }, + [254] = { .c = 0x07fffff0, .b = 27 }, + [255] = { .c = 0x03ffffee, .b = 26 }, + [256] = { .c = 0x3fffffff, .b = 30 }, /* EOS */ +}; + + +int main(int argc, char **argv) +{ + uint32_t c, i, j; + + /* fill first byte */ + printf("struct rht rht_bit31_24[256] = {\n"); + for (j = 0; j < 256; j++) { + for (i = 0; i < sizeof(ht)/sizeof(ht[0]); i++) { + if (ht[i].b > 8) + continue; + c = ht[i].c << (32 - ht[i].b); + + if (((c ^ (j << 24)) & -(1 << (32 - ht[i].b)) & 0xff000000) == 0) { + printf("\t[0x%02x] = { .c = 0x%02x, .l = %d },\n", j, i, ht[i].b); + break; + } + } + } + printf("};\n\n"); + + printf("struct rht rht_bit24_17[256] = {\n"); + for (j = 0; j < 256; j++) { + for (i = 0; i < sizeof(ht)/sizeof(ht[0]); i++) { + if (ht[i].b <= 8 || ht[i].b > 16) + continue; + c = ht[i].c << (32 - ht[i].b); + + if (((c ^ (j << 17)) & -(1 << (32 - ht[i].b)) & 0x01fe0000) == 0) { + printf("\t[0x%02x] = { .c = 0x%02x, .l = %d },\n", j, i, ht[i].b); + break; + } + } + } + printf("};\n\n"); + + printf("struct rht rht_bit15_11_fe[32] = {\n"); + for (j = 0; j < 32; j++) { + for (i = 0; i < sizeof(ht)/sizeof(ht[0]); i++) { + if (ht[i].b <= 16 || ht[i].b > 21) + continue; + c = ht[i].c << (32 - ht[i].b); + if ((c & 0x00ff0000) != 0x00fe0000) + continue; + + if (((c ^ (j << 11)) & -(1 << (32 - ht[i].b)) & 0x0000f800) == 0) { + printf("\t[0x%02x] = { .c = 0x%02x, .l = %d },\n", j, i, ht[i].b); + break; + } + } + } + printf("};\n\n"); + + printf("struct rht rht_bit15_8[256] = {\n"); + for (j = 0; j < 256; j++) { + for (i = 0; i < sizeof(ht)/sizeof(ht[0]); i++) { + if (ht[i].b <= 16 || ht[i].b > 24) + continue; + c = ht[i].c << (32 - ht[i].b); + if ((c & 0x00ff0000) != 0x00ff0000) + continue; + + if (((c ^ (j << 8)) & -(1 << (32 - ht[i].b)) & 0x0000ff00) == 0) { + printf("\t[0x%02x] = { .c = 0x%02x, .l = %d },\n", j, i, ht[i].b); + break; + } + } + } + printf("};\n\n"); + + printf("struct rht rht_bit11_4[256] = {\n"); + /* fill fourth byte after 0xff 0xff 0xf6-0xff. Only 0xfffffffx are not distinguished */ + for (j = 0; j < 256; j++) { + for (i = 0; i < sizeof(ht)/sizeof(ht[0]); i++) { + if (ht[i].b <= 24) + continue; + c = ht[i].c << (32 - ht[i].b); + + if (((c ^ (j << 4)) & -(1 << (32 - ht[i].b)) & 0x00000ff0) == 0) { + //printf("\tj=%02x i=%02x c=%08x l=%d c/l=%08x j/l=%08x xor=%08x\n", j, i, c, ht[i].b, c & -(1 << (32 - ht[i].b)), ((j << 4) & -(1 << (32 - ht[i].b))), (c ^ (j << 4)) & -(1 << (32 - ht[i].b))); + printf("\t[0x%02x] = { .c = 0x%02x, .l = %d },\n", j, i, ht[i].b); + break; + } + } + } + printf("\t/* Note, when l==30, bits 3..2 give 00:0x0a, 01:0x0d, 10:0x16, 11:EOS */\n"); + printf("};\n\n"); + return 0; +}