/* * QPACK header table management (draft-ietf-quic-qpack-20) * * Copyright 2020 HAProxy Technologies, Frederic Lecaille * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #include #include #include #include #include /* static header table as in draft-ietf-quic-qpack-20 Appendix A. */ const struct http_hdr qpack_sht[QPACK_SHT_SIZE] = { [ 0] = { .n = IST(":authority"), .v = IST("") }, [ 1] = { .n = IST(":path"), .v = IST("/") }, [ 2] = { .n = IST("age"), .v = IST("0") }, [ 3] = { .n = IST("content-disposition"), .v = IST("") }, [ 4] = { .n = IST("content-length"), .v = IST("0") }, [ 5] = { .n = IST("cookie"), .v = IST("") }, [ 6] = { .n = IST("date"), .v = IST("") }, [ 7] = { .n = IST("etag"), .v = IST("") }, [ 8] = { .n = IST("if-modified-since"), .v = IST("") }, [ 9] = { .n = IST("if-none-match"), .v = IST("") }, [10] = { .n = IST("last-modified"), .v = IST("") }, [11] = { .n = IST("link"), .v = IST("") }, [12] = { .n = IST("location"), .v = IST("") }, [13] = { .n = IST("referer"), .v = IST("") }, [14] = { .n = IST("set-cookie"), .v = IST("") }, [15] = { .n = IST(":method"), .v = IST("CONNECT") }, [16] = { .n = IST(":method"), .v = IST("DELETE") }, [17] = { .n = IST(":method"), .v = IST("GET") }, [18] = { .n = IST(":method"), .v = IST("HEAD") }, [19] = { .n = IST(":method"), .v = IST("OPTIONS") }, [20] = { .n = IST(":method"), .v = IST("POST") }, [21] = { .n = IST(":method"), .v = IST("PUT") }, [22] = { .n = IST(":scheme"), .v = IST("http") }, [23] = { .n = IST(":scheme"), .v = IST("https") }, [24] = { .n = IST(":status"), .v = IST("103") }, [25] = { .n = IST(":status"), .v = IST("200") }, [26] = { .n = IST(":status"), .v = IST("304") }, [27] = { .n = IST(":status"), .v = IST("404") }, [28] = { .n = IST(":status"), .v = IST("503") }, [29] = { .n = IST("accept"), .v = IST("*/*") }, [30] = { .n = IST("accept"), .v = IST("application/dns-message") }, [31] = { .n = IST("accept-encoding"), .v = IST("gzip, deflate, br") }, [32] = { .n = IST("accept-ranges"), .v = IST("bytes") }, [33] = { .n = IST("access-control-allow-headers"), .v = IST("cache-control") }, [34] = { .n = IST("access-control-allow-headers"), .v = IST("content-type") }, [35] = { .n = IST("access-control-allow-origin"), .v = IST("*") }, [36] = { .n = IST("cache-control"), .v = IST("max-age=0") }, [37] = { .n = IST("cache-control"), .v = IST("max-age=2592000") }, [38] = { .n = IST("cache-control"), .v = IST("max-age=604800") }, [39] = { .n = IST("cache-control"), .v = IST("no-cache") }, [40] = { .n = IST("cache-control"), .v = IST("no-store") }, [41] = { .n = IST("cache-control"), .v = IST("public, max-age=31536000") }, [42] = { .n = IST("content-encoding"), .v = IST("br") }, [43] = { .n = IST("content-encoding"), .v = IST("gzip") }, [44] = { .n = IST("content-type"), .v = IST("application/dns-message") }, [45] = { .n = IST("content-type"), .v = IST("application/javascript") }, [46] = { .n = IST("content-type"), .v = IST("application/json") }, [47] = { .n = IST("content-type"), .v = IST("application/" "x-www-form-urlencoded") }, [48] = { .n = IST("content-type"), .v = IST("image/gif") }, [49] = { .n = IST("content-type"), .v = IST("image/jpeg") }, [50] = { .n = IST("content-type"), .v = IST("image/png") }, [51] = { .n = IST("content-type"), .v = IST("text/css") }, [52] = { .n = IST("content-type"), .v = IST("text/html;" " charset=utf-8") }, [53] = { .n = IST("content-type"), .v = IST("text/plain") }, [54] = { .n = IST("content-type"), .v = IST("text/plain;" "charset=utf-8") }, [55] = { .n = IST("range"), .v = IST("bytes=0-") }, [56] = { .n = IST("strict-transport-security"), .v = IST("max-age=31536000") }, [57] = { .n = IST("strict-transport-security"), .v = IST("max-age=31536000;" " includesubdomains") }, [58] = { .n = IST("strict-transport-security"), .v = IST("max-age=31536000;" " includesubdomains;" " preload") }, [59] = { .n = IST("vary"), .v = IST("accept-encoding") }, [60] = { .n = IST("vary"), .v = IST("origin") }, [61] = { .n = IST("x-content-type-options"), .v = IST("nosniff") }, [62] = { .n = IST("x-xss-protection"), .v = IST("1; mode=block") }, [63] = { .n = IST(":status"), .v = IST("100") }, [64] = { .n = IST(":status"), .v = IST("204") }, [65] = { .n = IST(":status"), .v = IST("206") }, [66] = { .n = IST(":status"), .v = IST("302") }, [67] = { .n = IST(":status"), .v = IST("400") }, [68] = { .n = IST(":status"), .v = IST("403") }, [69] = { .n = IST(":status"), .v = IST("421") }, [70] = { .n = IST(":status"), .v = IST("425") }, [71] = { .n = IST(":status"), .v = IST("500") }, [72] = { .n = IST("accept-language"), .v = IST("") }, [73] = { .n = IST("access-control-allow-credentials"), .v = IST("FALSE") }, [74] = { .n = IST("access-control-allow-credentials"), .v = IST("TRUE") }, [75] = { .n = IST("access-control-allow-headers"), .v = IST("*") }, [76] = { .n = IST("access-control-allow-methods"), .v = IST("get") }, [77] = { .n = IST("access-control-allow-methods"), .v = IST("get, post, options") }, [78] = { .n = IST("access-control-allow-methods"), .v = IST("options") }, [79] = { .n = IST("access-control-expose-headers"), .v = IST("content-length") }, [80] = { .n = IST("access-control-request-headers"), .v = IST("content-type") }, [81] = { .n = IST("access-control-request-method"), .v = IST("get") }, [82] = { .n = IST("access-control-request-method"), .v = IST("post") }, [83] = { .n = IST("alt-svc"), .v = IST("clear") }, [84] = { .n = IST("authorization"), .v = IST("") }, [85] = { .n = IST("content-security-policy"), .v = IST("script-src 'none';" " object-src 'none';" " base-uri 'none'") }, [86] = { .n = IST("early-data"), .v = IST("1") }, [87] = { .n = IST("expect-ct"), .v = IST("") }, [88] = { .n = IST("forwarded"), .v = IST("") }, [89] = { .n = IST("if-range"), .v = IST("") }, [90] = { .n = IST("origin"), .v = IST("") }, [91] = { .n = IST("purpose"), .v = IST("prefetch") }, [92] = { .n = IST("server"), .v = IST("") }, [93] = { .n = IST("timing-allow-origin"), .v = IST("*") }, [94] = { .n = IST("upgrade-insecure-requests"), .v = IST("1") }, [95] = { .n = IST("user-agent"), .v = IST("") }, [96] = { .n = IST("x-forwarded-for"), .v = IST("") }, [97] = { .n = IST("x-frame-options"), .v = IST("deny") }, [98] = { .n = IST("x-frame-options"), .v = IST("sameorigin") }, }; struct pool_head *pool_head_qpack_tbl = NULL; #ifdef DEBUG_QPACK /* dump the whole dynamic header table */ void qpack_dht_dump(FILE *out, const struct qpack_dht *dht) { unsigned int i; unsigned int slot; char name[4096], value[4096]; for (i = QPACK_SHT_SIZE; i < QPACK_SHT_SIZE + dht->used; i++) { slot = (qpack_get_dte(dht, i - QPACK_SHT_SIZE + 1) - dht->dte); fprintf(out, "idx=%u slot=%u name=<%s> value=<%s> addr=%u-%u\n", i, slot, istpad(name, qpack_idx_to_name(dht, i)).ptr, istpad(value, qpack_idx_to_value(dht, i)).ptr, dht->dte[slot].addr, dht->dte[slot].addr+dht->dte[slot].nlen+dht->dte[slot].vlen-1); } } /* check for the whole dynamic header table consistency, abort on failures */ void qpack_dht_check_consistency(const struct qpack_dht *dht) { unsigned slot = qpack_dht_get_tail(dht); unsigned used2 = dht->used; unsigned total = 0; if (!dht->used) return; if (dht->front >= dht->wrap) abort(); if (dht->used > dht->wrap) abort(); if (dht->head >= dht->wrap) abort(); while (used2--) { total += dht->dte[slot].nlen + dht->dte[slot].vlen; slot++; if (slot >= dht->wrap) slot = 0; } if (total != dht->total) { fprintf(stderr, "%d: total=%u dht=%u\n", __LINE__, total, dht->total); abort(); } } #endif // DEBUG_QPACK /* rebuild a new dynamic header table from with an unwrapped index and * contents at the end. The new table is returned, the caller must not use the * previous one anymore. NULL may be returned if no table could be allocated. */ static struct qpack_dht *qpack_dht_defrag(struct qpack_dht *dht) { struct qpack_dht *alt_dht; uint16_t old, new; uint32_t addr; /* Note: for small tables we could use alloca() instead but * portability especially for large tables can be problematic. */ alt_dht = qpack_dht_alloc(); if (!alt_dht) return NULL; alt_dht->total = dht->total; alt_dht->used = dht->used; alt_dht->wrap = dht->used; new = 0; addr = alt_dht->size; if (dht->used) { /* start from the tail */ old = qpack_dht_get_tail(dht); do { alt_dht->dte[new].nlen = dht->dte[old].nlen; alt_dht->dte[new].vlen = dht->dte[old].vlen; addr -= dht->dte[old].nlen + dht->dte[old].vlen; alt_dht->dte[new].addr = addr; memcpy((void *)alt_dht + alt_dht->dte[new].addr, (void *)dht + dht->dte[old].addr, dht->dte[old].nlen + dht->dte[old].vlen); old++; if (old >= dht->wrap) old = 0; new++; } while (new < dht->used); } alt_dht->front = alt_dht->head = new - 1; memcpy(dht, alt_dht, dht->size); qpack_dht_free(alt_dht); return dht; } /* Purges table dht until a header field of bytes fits according to * the protocol (adding 32 bytes overhead). Returns non-zero on success, zero * on failure (ie: table empty but still not sufficient). It must only be * called when the table is not large enough to suit the new entry and there * are some entries left. In case of doubt, use dht_make_room() instead. */ int __qpack_dht_make_room(struct qpack_dht *dht, unsigned int needed) { unsigned int used = dht->used; unsigned int wrap = dht->wrap; unsigned int tail; do { tail = ((dht->head + 1U < used) ? wrap : 0) + dht->head + 1U - used; dht->total -= dht->dte[tail].nlen + dht->dte[tail].vlen; if (tail == dht->front) dht->front = dht->head; used--; } while (used && used * 32 + dht->total + needed + 32 > dht->size); dht->used = used; /* realign if empty */ if (!used) dht->front = dht->head = 0; /* pack the table if it doesn't wrap anymore */ if (dht->head + 1U >= used) dht->wrap = dht->head + 1; /* no need to check for 'used' here as if it doesn't fit, used==0 */ return needed + 32 <= dht->size; } /* tries to insert a new header : in front of the current head. A * negative value is returned on error. */ int qpack_dht_insert(struct qpack_dht *dht, struct ist name, struct ist value) { unsigned int used; unsigned int head; unsigned int prev; unsigned int wrap; unsigned int tail; uint32_t headroom, tailroom; if (!qpack_dht_make_room(dht, name.len + value.len)) return 0; /* Now there is enough room in the table, that's guaranteed by the * protocol, but not necessarily where we need it. */ used = dht->used; if (!used) { /* easy, the table was empty */ dht->front = dht->head = 0; dht->wrap = dht->used = 1; dht->total = 0; head = 0; dht->dte[head].addr = dht->size - (name.len + value.len); goto copy; } /* compute the new head, used and wrap position */ prev = head = dht->head; wrap = dht->wrap; tail = qpack_dht_get_tail(dht); used++; head++; if (head >= wrap) { /* head is leading the entries, we either need to push the * table further or to loop back to released entries. We could * force to loop back when at least half of the allocatable * entries are free but in practice it never happens. */ if ((sizeof(*dht) + (wrap + 1) * sizeof(dht->dte[0]) <= dht->dte[dht->front].addr)) wrap++; else if (head >= used) /* there's a hole at the beginning */ head = 0; else { /* no more room, head hits tail and the index cannot be * extended, we have to realign the whole table. */ if (!qpack_dht_defrag(dht)) return -1; wrap = dht->wrap + 1; head = dht->head + 1; prev = head - 1; tail = 0; } } else if (used >= wrap) { /* we've hit the tail, we need to reorganize the index so that * the head is at the end (but not necessarily move the data). */ if (!qpack_dht_defrag(dht)) return -1; wrap = dht->wrap + 1; head = dht->head + 1; prev = head - 1; tail = 0; } /* Now we have updated head, used and wrap, we know that there is some * available room at least from the protocol's perspective. This space * is split in two areas : * * 1: if the previous head was the front cell, the space between the * end of the index table and the front cell's address. * 2: if the previous head was the front cell, the space between the * end of the tail and the end of the table ; or if the previous * head was not the front cell, the space between the end of the * tail and the head's address. */ if (prev == dht->front) { /* the area was contiguous */ headroom = dht->dte[dht->front].addr - (sizeof(*dht) + wrap * sizeof(dht->dte[0])); tailroom = dht->size - dht->dte[tail].addr - dht->dte[tail].nlen - dht->dte[tail].vlen; } else { /* it's already wrapped so we can't store anything in the headroom */ headroom = 0; tailroom = dht->dte[prev].addr - dht->dte[tail].addr - dht->dte[tail].nlen - dht->dte[tail].vlen; } /* We can decide to stop filling the headroom as soon as there's enough * room left in the tail to suit the protocol, but tests show that in * practice it almost never happens in other situations so the extra * test is useless and we simply fill the headroom as long as it's * available and we don't wrap. */ if (prev == dht->front && headroom >= name.len + value.len) { /* install upfront and update ->front */ dht->dte[head].addr = dht->dte[dht->front].addr - (name.len + value.len); dht->front = head; } else if (tailroom >= name.len + value.len) { dht->dte[head].addr = dht->dte[tail].addr + dht->dte[tail].nlen + dht->dte[tail].vlen + tailroom - (name.len + value.len); } else { /* need to defragment the table before inserting upfront */ dht = qpack_dht_defrag(dht); wrap = dht->wrap + 1; head = dht->head + 1; dht->dte[head].addr = dht->dte[dht->front].addr - (name.len + value.len); dht->front = head; } dht->wrap = wrap; dht->head = head; dht->used = used; copy: dht->total += name.len + value.len; dht->dte[head].nlen = name.len; dht->dte[head].vlen = value.len; memcpy((void *)dht + dht->dte[head].addr, name.ptr, name.len); memcpy((void *)dht + dht->dte[head].addr + name.len, value.ptr, value.len); return 0; }