--- /dev/null
+/*
+ * HPACK header table management (RFC7541) - type definitions and prototypes
+ *
+ * Copyright (C) 2014-2017 Willy Tarreau <willy@haproxy.org>
+ * Copyright (C) 2017 HAProxy Technologies
+ *
+ * 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.
+ */
+#ifndef _COMMON_HPACK_TBL_H
+#define _COMMON_HPACK_TBL_H
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <common/config.h>
+#include <common/http-hdr.h>
+#include <common/ist.h>
+
+/* Dynamic Headers Table, usable for tables up to 4GB long and values of 64kB-1.
+ * The model can be improved by using offsets relative to the table entry's end
+ * or to the end of the area, or by moving the descriptors at the end of the
+ * table and the data at the beginning. This entry is 8 bytes long, which is 1/4
+ * of the bookkeeping planned by the HPACK spec. Thus it saves 24 bytes per
+ * header field, meaning that even with a single header, 24 extra bytes can be
+ * stored (ie one such descriptor). At 29.2 average bytes per header field as
+ * found in the hpack test case, that's slightly more than 1.5kB of space saved
+ * from a 4kB block, resulting in contiguous space almost always being
+ * available.
+ *
+ * Principle: the table is stored in a contiguous array containing both the
+ * descriptors and the contents. Descriptors are stored at the beginning of the
+ * array while contents are stored starting from the end. Most of the time there
+ * is enough room left in the table to insert a new header field, thanks to the
+ * savings on the descriptor size. Thus by inserting headers from the end it's
+ * possible to maximize the delay before a collision of DTEs and data. In order
+ * to always insert from the right, we need to keep a reference to the latest
+ * inserted element and look before it. The last inserted cell's address defines
+ * the lowest konwn address still in use, unless the area wraps in which case
+ * the available space lies between the end of the tail and the beginning of the
+ * head.
+ *
+ * In order to detect collisions between data blocks and DTEs, we also maintain
+ * an index to the lowest element facing the DTE table, called "front". This one
+ * is updated each time an element is inserted before it. Once the buffer wraps,
+ * this element doesn't have to be updated anymore until it is released, in
+ * which case the buffer doesn't wrap anymore and the front element becomes the
+ * head again.
+ *
+ * Various heuristics are possible concerning the opportunity to wrap the
+ * entries to limit the risk of collisions with the DTE, but experimentation
+ * shows that thanks to the important savings made on the descriptors, the
+ * likeliness of finding a large amount of free space at the end of the area is
+ * much higher than the risk of colliding, so in the end the most naive
+ * algorithms work pretty fine. Typical ratios of 1 collision per 2000 requests
+ * have been observed.
+ *
+ * The defragmentation should be rare ; a study on live data shows on average
+ * 29.2 bytes used per header field. This plus the 32 bytes overhead fix an
+ * average of 66.9 header fields per 4kB table. This brings a 1606 bytes saving
+ * using the current storage description, ensuring that oldest headers are
+ * linearly removed by the sender before fragmentation occurs. This means that
+ * for all smaller header fields there will not be any requirement to defragment
+ * the area and most of the time it will even be possible to copy the old values
+ * directly within the buffer after creating a new entry. On average within the
+ * available space there will be enough room to store 1606/(29.2+8)=43 extra
+ * header fields without switching to another place.
+ *
+ * The table header fits in the table itself, it only takes 16 bytes, so in the
+ * worst case (1 single header) it's possible to store 4096 - 16 - 8 = 4072
+ * data bytes, which is larger than the 4064 the protocol requires (4096 - 32).
+ */
+
+/* One dynamic table entry descriptor */
+struct hpack_dte {
+ uint32_t addr; /* storage address, relative to the dte address */
+ uint16_t nlen; /* header name length */
+ uint16_t vlen; /* header value length */
+};
+
+/* Note: the table's head plus a struct hpack_dte must be smaller than or equal to 32
+ * bytes so that a single large header can always fit. Here that's 16 bytes for
+ * the header, plus 8 bytes per slot.
+ * Note that when <used> == 0, front, head, and wrap are undefined.
+ */
+struct hpack_dht {
+ uint32_t size; /* allocated table size in bytes */
+ uint32_t total; /* sum of nlen + vlen in bytes */
+ uint16_t front; /* slot number of the first node after the idx table */
+ uint16_t wrap; /* number of allocated slots, wraps here */
+ uint16_t head; /* last inserted slot number */
+ uint16_t used; /* number of slots in use */
+ struct hpack_dte dte[0]; /* dynamic table entries */
+};
+
+/* supported hpack encoding/decoding errors */
+enum {
+ HPACK_ERR_NONE = 0, /* no error */
+ HPACK_ERR_ALLOC_FAIL, /* memory allocation error */
+ HPACK_ERR_UNKNOWN_OPCODE, /* invalid first byte */
+ HPACK_ERR_TRUNCATED, /* truncated stream */
+ HPACK_ERR_HUFFMAN, /* huffman decoding error */
+ HPACK_ERR_INVALID_PHDR, /* invalid pseudo header field name */
+ HPACK_ERR_MISPLACED_PHDR, /* pseudo header field after a regular header field */
+ HPACK_ERR_DUPLICATE_PHDR, /* duplicate pseudo header field */
+ HPACK_ERR_DHT_INSERT_FAIL, /* failed to insert into DHT */
+ HPACK_ERR_TOO_LARGE, /* decoded request/response is too large */
+ HPACK_ERR_MISSING_METHOD, /* :method is missing */
+ HPACK_ERR_MISSING_SCHEME, /* :scheme is missing */
+ HPACK_ERR_MISSING_PATH, /* :path is missing */
+ HPACK_ERR_MISSING_AUTHORITY, /* :authority is missing with CONNECT */
+ HPACK_ERR_SCHEME_NOT_ALLOWED, /* :scheme not allowed with CONNECT */
+ HPACK_ERR_PATH_NOT_ALLOWED, /* :path not allowed with CONNECT */
+};
+
+/* static header table as in RFC7541 Appendix A. [0] unused. */
+#define HPACK_SHT_SIZE 62
+extern const struct http_hdr hpack_sht[HPACK_SHT_SIZE];
+
+extern int __hpack_dht_make_room(struct hpack_dht *dht, unsigned int needed);
+extern int hpack_dht_insert(struct hpack_dht *dht, struct ist name, struct ist value);
+
+/* return a pointer to the entry designated by index <idx> (starting at 1) or
+ * NULL if this index is not there.
+ */
+static inline const struct hpack_dte *hpack_get_dte(const struct hpack_dht *dht, uint16_t idx)
+{
+ idx--;
+
+ if (idx >= dht->used)
+ return NULL;
+
+ if (idx <= dht->head)
+ idx = dht->head - idx;
+ else
+ idx = dht->head - idx + dht->wrap;
+
+ return &dht->dte[idx];
+}
+
+/* return a pointer to the header name for entry <dte>. */
+static inline struct ist hpack_get_name(const struct hpack_dht *dht, const struct hpack_dte *dte)
+{
+ struct ist ret = {
+ .ptr = (void *)dht + dte->addr,
+ .len = dte->nlen,
+ };
+ return ret;
+}
+
+/* return a pointer to the header value for entry <dte>. */
+static inline struct ist hpack_get_value(const struct hpack_dht *dht, const struct hpack_dte *dte)
+{
+ struct ist ret = {
+ .ptr = (void *)dht + dte->addr + dte->nlen,
+ .len = dte->vlen,
+ };
+ return ret;
+}
+
+/* takes an idx, returns the associated name */
+static inline struct ist hpack_idx_to_name(const struct hpack_dht *dht, int idx)
+{
+ const struct hpack_dte *dte;
+
+ if (idx < HPACK_SHT_SIZE)
+ return hpack_sht[idx].n;
+
+ dte = hpack_get_dte(dht, idx - HPACK_SHT_SIZE + 1);
+ if (!dte)
+ return ist("### ERR ###"); // error
+
+ return hpack_get_name(dht, dte);
+}
+
+/* takes an idx, returns the associated value */
+static inline struct ist hpack_idx_to_value(const struct hpack_dht *dht, int idx)
+{
+ const struct hpack_dte *dte;
+
+ if (idx < HPACK_SHT_SIZE)
+ return hpack_sht[idx].v;
+
+ dte = hpack_get_dte(dht, idx - HPACK_SHT_SIZE + 1);
+ if (!dte)
+ return ist("### ERR ###"); // error
+
+ return hpack_get_value(dht, dte);
+}
+
+/* Purges table dht until a header field of <needed> 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).
+ */
+static inline int hpack_dht_make_room(struct hpack_dht *dht, unsigned int needed)
+{
+ if (!dht->used || dht->used * 32 + dht->total + needed + 32 <= dht->size)
+ return 1;
+
+ return __hpack_dht_make_room(dht, needed);
+}
+
+/* allocate a dynamic headers table of <size> bytes and return it initialized */
+static inline void hpack_dht_init(struct hpack_dht *dht, uint32_t size)
+{
+ dht->size = size;
+ dht->total = 0;
+ dht->used = 0;
+}
+
+/* allocate a dynamic headers table of <size> bytes and return it initialized */
+static inline struct hpack_dht *hpack_dht_alloc(uint32_t size)
+{
+ struct hpack_dht *dht;
+
+ dht = malloc(size);
+ if (!dht)
+ return dht;
+
+ hpack_dht_init(dht, size);
+ return dht;
+}
+
+/* free a dynamic headers table */
+static inline void hpack_dht_free(struct hpack_dht *dht)
+{
+ free(dht);
+}
+
+#endif /* _COMMON_HPACK_TBL_H */
--- /dev/null
+/*
+ * HPACK header table management (RFC7541)
+ *
+ * Copyright (C) 2014-2017 Willy Tarreau <willy@haproxy.org>
+ * Copyright (C) 2017 HAProxy Technologies
+ *
+ * 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 <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <common/hpack-huff.h>
+#include <common/hpack-tbl.h>
+#include <common/ist.h>
+
+#include <types/global.h>
+
+/* static header table as in RFC7541 Appendix A. [0] unused. */
+const struct http_hdr hpack_sht[HPACK_SHT_SIZE] = {
+ [ 1] = { .n = IST(":authority"), .v = IST("") },
+ [ 2] = { .n = IST(":method"), .v = IST("GET") },
+ [ 3] = { .n = IST(":method"), .v = IST("POST") },
+ [ 4] = { .n = IST(":path"), .v = IST("/") },
+ [ 5] = { .n = IST(":path"), .v = IST("/index.html") },
+ [ 6] = { .n = IST(":scheme"), .v = IST("http") },
+ [ 7] = { .n = IST(":scheme"), .v = IST("https") },
+ [ 8] = { .n = IST(":status"), .v = IST("200") },
+ [ 9] = { .n = IST(":status"), .v = IST("204") },
+ [10] = { .n = IST(":status"), .v = IST("206") },
+ [11] = { .n = IST(":status"), .v = IST("304") },
+ [12] = { .n = IST(":status"), .v = IST("400") },
+ [13] = { .n = IST(":status"), .v = IST("404") },
+ [14] = { .n = IST(":status"), .v = IST("500") },
+ [15] = { .n = IST("accept-charset"), .v = IST("") },
+ [16] = { .n = IST("accept-encoding"), .v = IST("gzip, deflate") },
+ [17] = { .n = IST("accept-language"), .v = IST("") },
+ [18] = { .n = IST("accept-ranges"), .v = IST("") },
+ [19] = { .n = IST("accept"), .v = IST("") },
+ [20] = { .n = IST("access-control-allow-origin"), .v = IST("") },
+ [21] = { .n = IST("age"), .v = IST("") },
+ [22] = { .n = IST("allow"), .v = IST("") },
+ [23] = { .n = IST("authorization"), .v = IST("") },
+ [24] = { .n = IST("cache-control"), .v = IST("") },
+ [25] = { .n = IST("content-disposition"), .v = IST("") },
+ [26] = { .n = IST("content-encoding"), .v = IST("") },
+ [27] = { .n = IST("content-language"), .v = IST("") },
+ [28] = { .n = IST("content-length"), .v = IST("") },
+ [29] = { .n = IST("content-location"), .v = IST("") },
+ [30] = { .n = IST("content-range"), .v = IST("") },
+ [31] = { .n = IST("content-type") , .v = IST("") },
+ [32] = { .n = IST("cookie"), .v = IST("") },
+ [33] = { .n = IST("date"), .v = IST("") },
+ [34] = { .n = IST("etag"), .v = IST("") },
+ [35] = { .n = IST("expect"), .v = IST("") },
+ [36] = { .n = IST("expires"), .v = IST("") },
+ [37] = { .n = IST("from"), .v = IST("") },
+ [38] = { .n = IST("host"), .v = IST("") },
+ [39] = { .n = IST("if-match"), .v = IST("") },
+ [40] = { .n = IST("if-modified-since"), .v = IST("") },
+ [41] = { .n = IST("if-none-match"), .v = IST("") },
+ [42] = { .n = IST("if-range"), .v = IST("") },
+ [43] = { .n = IST("if-unmodified-since"), .v = IST("") },
+ [44] = { .n = IST("last-modified"), .v = IST("") },
+ [45] = { .n = IST("link"), .v = IST("") },
+ [46] = { .n = IST("location"), .v = IST("") },
+ [47] = { .n = IST("max-forwards"), .v = IST("") },
+ [48] = { .n = IST("proxy-authenticate"), .v = IST("") },
+ [49] = { .n = IST("proxy-authorization"), .v = IST("") },
+ [50] = { .n = IST("range"), .v = IST("") },
+ [51] = { .n = IST("referer"), .v = IST("") },
+ [52] = { .n = IST("refresh"), .v = IST("") },
+ [53] = { .n = IST("retry-after"), .v = IST("") },
+ [54] = { .n = IST("server"), .v = IST("") },
+ [55] = { .n = IST("set-cookie"), .v = IST("") },
+ [56] = { .n = IST("strict-transport-security"), .v = IST("") },
+ [57] = { .n = IST("transfer-encoding"), .v = IST("") },
+ [58] = { .n = IST("user-agent"), .v = IST("") },
+ [59] = { .n = IST("vary"), .v = IST("") },
+ [60] = { .n = IST("via"), .v = IST("") },
+ [61] = { .n = IST("www-authenticate"), .v = IST("") },
+};
+
+/* returns the slot number of the oldest entry (tail). Must not be used on an
+ * empty table.
+ */
+static inline unsigned int hpack_dht_get_tail(const struct hpack_dht *dht)
+{
+ return ((dht->head + 1U < dht->used) ? dht->wrap : 0) + dht->head + 1U - dht->used;
+}
+
+#ifdef DEBUG_HPACK
+/* dump the whole dynamic header table */
+static void hpack_dht_dump(const struct hpack_dht *dht)
+{
+ int i;
+ unsigned int slot;
+ char name[4096], value[4096];
+
+ for (i = HPACK_SHT_SIZE; i < HPACK_SHT_SIZE + dht->used; i++) {
+ slot = (hpack_get_dte(dht, i - HPACK_SHT_SIZE + 1) - dht->dte);
+ fprintf(stderr, "idx=%d slot=%u name=<%s> value=<%s> addr=%u-%u\n",
+ i, slot,
+ istpad(name, hpack_idx_to_name(dht, i)).ptr,
+ istpad(value, hpack_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 */
+static void hpack_dht_check_consistency(const struct hpack_dht *dht)
+{
+ unsigned slot = hpack_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_HPACK
+
+/* rebuild a new dynamic header table from <dht> 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 hpack_dht *hpack_dht_defrag(struct hpack_dht *dht)
+{
+ struct hpack_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 = hpack_dht_alloc(dht->size);
+ 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 = hpack_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);
+ hpack_dht_free(alt_dht);
+
+ return dht;
+}
+
+/* Purges table dht until a header field of <needed> 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 __hpack_dht_make_room(struct hpack_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 <name>:<value> in front of the current head. A
+ * negative value is returned on error.
+ */
+int hpack_dht_insert(struct hpack_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 (!hpack_dht_make_room(dht, name.len + value.len))
+ return -1;
+
+ used = dht->used;
+ prev = head = dht->head;
+ wrap = dht->wrap;
+ tail = hpack_dht_get_tail(dht);
+
+ /* Now there is enough room in the table, that's guaranteed by the
+ * protocol, but not necessarily where we need it.
+ */
+
+ 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 */
+ 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 (!hpack_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 (!hpack_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.
+ */
+ if (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 = hpack_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;
+}
projects / thirdparty / haproxy.git / commitdiff
