/***************************************************************************** * hpackenc.c: HPACK Header Compression for HTTP/2 encoder ***************************************************************************** * Copyright (C) 2015 Rémi Denis-Courmont * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/ #ifdef HAVE_CONFIG_H # include #endif #ifdef ENC_TEST # undef NDEBUG #endif #include #include #include #include "hpack.h" /* * This is currently the simplest possible HPACK compressor: it does not * compress anything and is stateless. * TODO: * - use static Huffman compression when useful, * - use header names and values from the static HPACK table, * - become stateful and let the caller specify the indexed flag, * - let caller specify the never-indexed flag. */ static size_t hpack_encode_int(uint8_t *restrict buf, size_t size, uintmax_t value, unsigned n) { assert(n >= 1 && n <= 8); unsigned mask = (1 << n) - 1; size_t ret = 1; if (value < mask) { if (size > 0) buf[0] |= value; return 1; } if (size > 0) *(buf++) |= mask; value -= mask; while (value >= 128) { if (ret++ < size) *(buf++) = 0x80 | (value & 0x7F); value >>= 7; } if (ret++ < size) *(buf++) = value; return ret; } static size_t hpack_encode_str_raw(uint8_t *restrict buf, size_t size, const char *str) { size_t len = strlen(str); if (size > 0) *buf = 0; size_t ret = hpack_encode_int(buf, size, len, 7); if (ret < size) { buf += ret; size -= ret; memcpy(buf, str, (len <= size) ? len : size); } ret += len; return ret; } static size_t hpack_encode_str_raw_lower(uint8_t *restrict buf, size_t size, const char *str) { size_t len = strlen(str); if (size > 0) *buf = 0; size_t ret = hpack_encode_int(buf, size, len, 7); if (ret < size) { buf += ret; size -= ret; for (size_t i = 0; i < len && i < size; i++) if (str[i] < 'A' || str[i] > 'Z') buf[i] = str[i]; else buf[i] = str[i] - 'A' + 'a'; } ret += len; return ret; } size_t hpack_encode_hdr_neverindex(uint8_t *restrict buf, size_t size, const char *name, const char *value) { size_t ret = 1, val; if (size > 0) { *(buf++) = 0x10; size--; } val = hpack_encode_str_raw_lower(buf, size, name); if (size >= val) { buf += val; size -= val; } else size = 0; ret += val; val = hpack_encode_str_raw(buf, size, value); if (size >= val) { buf += val; size -= val; } else size = 0; ret += val; return ret; } size_t hpack_encode(uint8_t *restrict buf, size_t size, const char *const headers[][2], unsigned count) { size_t ret = 0; while (count > 0) { size_t val = hpack_encode_hdr_neverindex(buf, size, headers[0][0], headers[0][1]); if (size >= val) { buf += val; size -= val; } else size = 0; ret += val; headers++; count--; } return ret; } /*** Test cases ***/ #ifdef ENC_TEST # include # include # include static void test_integer(unsigned n, uintmax_t value) { uint8_t buf[3]; size_t ret; for (unsigned i = 0; i < 3; i++) { ret = hpack_encode_int(buf, sizeof (buf), value, n); assert(ret > 0); } } static void test_integers(void) { test_integer(5, 10); test_integer(5, 1337); test_integer(8, 42); } static void test_lowercase(const char *str) { char c; while ((c = *(str++)) != '\0') assert(c < 'A' || c > 'Z'); } static void test_block(const char *name, ...) { const char *headers[16][2]; unsigned count = 0; va_list ap; va_start(ap, name); while (name != NULL) { headers[count][0] = name; headers[count][1] = va_arg(ap, const char *); name = va_arg(ap, const char *); count++; } va_end(ap); printf(" %u header(s):\n", count); uint8_t buf[1024]; size_t length = hpack_encode(NULL, 0, headers, count); for (size_t i = 0; i < sizeof (buf); i++) assert(hpack_encode(buf, i, headers, count) == length); memset(buf, 0xAA, sizeof (buf)); assert(hpack_encode(buf, length, headers, count) == length); char *eheaders[16][2]; struct hpack_decoder *dec = hpack_decode_init(4096); assert(dec != NULL); int ecount = hpack_decode(dec, buf, length, eheaders, 16); assert((unsigned)ecount == count); hpack_decode_destroy(dec); for (unsigned i = 0; i < count; i++) { printf(" %s: %s\n", eheaders[i][0], eheaders[i][1]); test_lowercase(eheaders[i][0]); assert(!strcasecmp(eheaders[i][0], headers[i][0])); assert(!strcmp(eheaders[i][1], headers[i][1])); free(eheaders[i][1]); free(eheaders[i][0]); } } static void test_reqs(void) { test_block(NULL); test_block(":method", "GET", ":scheme", "http", ":path", "/", ":authority", "www.example.com", NULL); test_block(":method", "GET", ":scheme", "http", ":path", "/", ":authority", "www.example.com", "Cache-Control", "no-cache", NULL); test_block(":method", "GET", ":scheme", "https", ":path", "/index.html", ":authority", "www.example.com", "custom-key", "custom-value", NULL); } static void test_resps(void) { test_block(":status", "302", "Cache-Control", "private", "Date", "Mon, 21 Oct 2013 20:13:21 GMT", "Location", "https://www.example.com", NULL); test_block(":status", "307", "Cache-Control", "private", "Date", "Mon, 21 Oct 2013 20:13:21 GMT", "Location", "https://www.example.com", NULL); test_block(":status", "200", "Cache-Control", "private", "Date", "Mon, 21 Oct 2013 20:13:22 GMT", "Location", "https://www.example.com", "Content-Encoding", "gzip", "Set-Cookie", "foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; " "max-age=3600; version=1", NULL); } int main(void) { test_integers(); test_reqs(); test_resps(); } #endif /* TEST */