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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 09:35:11 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 09:35:11 +0000 |
commit | da76459dc21b5af2449af2d36eb95226cb186ce2 (patch) | |
tree | 542ebb3c1e796fac2742495b8437331727bbbfa0 /dev/hpack/gen-enc.c | |
parent | Initial commit. (diff) | |
download | haproxy-upstream.tar.xz haproxy-upstream.zip |
Adding upstream version 2.6.12.upstream/2.6.12upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | dev/hpack/gen-enc.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/dev/hpack/gen-enc.c b/dev/hpack/gen-enc.c new file mode 100644 index 0000000..3fc5ef9 --- /dev/null +++ b/dev/hpack/gen-enc.c @@ -0,0 +1,205 @@ +/* + * HPACK encoding table generator. It produces a stream of + * <len><idx><name> and a table pointing to the first <len> of each series. + * The end of the stream is marked by <len>=0. In parallel, a length-indexed + * table is built to access the first entry of each length. + * + * Build like this : + * gcc -I../../include -o gen-enc gen-enc.c + */ +#define HPACK_STANDALONE + +#include <ctype.h> +#include <inttypes.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <import/ist.h> +#include <haproxy/hpack-tbl-t.h> +#include "../../src/hpack-tbl.c" + +struct idxhdr { + const char *ptr; + int len; + int idx; +}; + +struct idxhdr idxhdr[HPACK_SHT_SIZE]; +static int positions[32]; +static char known_hdr[1024]; + +/* preferred ordering of headers of similar size. Those not mentioned will be + * less prioritized. + */ +const struct { + const char *name; + const int rank; +} ranks[] = { + { .name = "age", .rank = 1 }, + { .name = "via", .rank = 2 }, + + { .name = "date", .rank = 1 }, + { .name = "host", .rank = 2 }, + + { .name = "accept", .rank = 1 }, + { .name = "server", .rank = 2 }, + { .name = "cookie", .rank = 3 }, + + { .name = "referer", .rank = 1 }, + { .name = "expires", .rank = 2 }, + + { .name = "location", .rank = 1 }, + + { .name = "user-agent", .rank = 1 }, + { .name = "set-cookie", .rank = 2 }, + + { .name = "content-type", .rank = 1 }, + + { .name = "cache-control", .rank = 1 }, + { .name = "last-modified", .rank = 2 }, + { .name = "accept-ranges", .rank = 3 }, + { .name = "if-none-match", .rank = 4 }, + + { .name = "content-length", .rank = 1 }, + + { .name = "accept-encoding", .rank = 1 }, + { .name = "accept-language", .rank = 2 }, + + { .name = "content-encoding", .rank = 1 }, + + { .name = "transfer-encoding", .rank = 1 }, + { .name = "if-modified-since", .rank = 2 }, + + { .name = "content-disposition", .rank = 1 }, +}; + +/* returns the rank of header <name> or 255 if not found */ +int get_hdr_rank(const char *name) +{ + int i; + + for (i = 0; i < sizeof(ranks) / sizeof(ranks[0]); i++) { + if (strcmp(ranks[i].name, name) == 0) + return ranks[i].rank; + } + return 255; +} + +/* sorts first on the length, second on the name, and third on the idx, so that + * headers which appear with multiple occurrences are always met first. + */ +int cmp_idx(const void *l, const void *r) +{ + const struct idxhdr *a = l, *b = r; + int ranka, rankb; + int ret; + + if (a->len < b->len) + return -1; + else if (a->len > b->len) + return 1; + + ranka = get_hdr_rank(a->ptr); + rankb = get_hdr_rank(b->ptr); + + if (ranka < rankb) + return -1; + else if (ranka > rankb) + return 1; + + /* same rank, check for duplicates and use index */ + ret = strcmp(a->ptr, b->ptr); + if (ret != 0) + return ret; + + if (a->idx < b->idx) + return -1; + else if (a->idx > b->idx) + return 1; + else + return 0; +} + +int main(int argc, char **argv) +{ + int pos; + int prev; + int len; + int i; + + for (len = 0; len < 32; len++) + positions[len] = -1; + + for (i = 0; i < HPACK_SHT_SIZE; i++) { + idxhdr[i].ptr = hpack_sht[i].n.ptr; + idxhdr[i].len = hpack_sht[i].n.len; + idxhdr[i].idx = i; + } + + /* sorts all header names by length first, then by name, and finally by + * idx so that we meet smaller headers first, that within a length they + * appear in frequency order, and that multiple occurrences appear with + * the smallest index first. + */ + qsort(&idxhdr[1], HPACK_SHT_SIZE - 1, sizeof(idxhdr[0]), cmp_idx); + + pos = 0; + prev = -1; + for (i = 1; i < HPACK_SHT_SIZE; i++) { + len = idxhdr[i].len; + if (len > 31) { + //printf("skipping %s (len=%d)\n", idxhdr[i].ptr, idxhdr[i].len); + continue; + } + + /* first occurrence of this length? */ + if (positions[len] == -1) + positions[len] = pos; + else if (prev >= 0 && + memcmp(&known_hdr[prev] + 2, idxhdr[i].ptr, len) == 0) { + /* duplicate header field */ + continue; + } + + /* store <len> <idx> <name> in the output array */ + + if (pos + 1 + len + 2 >= sizeof(known_hdr)) + abort(); + + prev = pos; + known_hdr[pos++] = len; + known_hdr[pos++] = idxhdr[i].idx; + memcpy(&known_hdr[pos], idxhdr[i].ptr, len); + pos += len; + //printf("%d %d %s\n", len, idxhdr[i].idx, idxhdr[i].ptr); + } + + if (pos + 1 >= sizeof(known_hdr)) + abort(); + known_hdr[pos++] = 0; // size zero ends the stream + + printf("const char hpack_enc_stream[%d] = {\n", pos); + for (i = 0; i < pos; i++) { + if ((i & 7) == 0) + printf("\t /* % 4d: */", i); + + printf(" 0x%02x,", known_hdr[i]); + + if ((i & 7) == 7 || (i == pos - 1)) + putchar('\n'); + } + printf("};\n\n"); + + printf("const signed short hpack_pos_len[32] = {\n"); + for (i = 0; i < 32; i++) { + if ((i & 7) == 0) + printf("\t /* % 4d: */", i); + + printf(" % 4d,", positions[i]); + + if ((i & 7) == 7 || (i == pos - 1)) + putchar('\n'); + } + printf("};\n\n"); + return 0; +} |