MINOR: cache: Improve accept_encoding_normalizer

Turn the "Accept-Encoding" value to lower case before processing it.
Calculate the CRC on every token instead of a sorted concatenation of
them all (in order to avoir copying them) then XOR all the CRCs into a
single hash (while ignoring duplicates).
This commit is contained in:
Remi Tricot-Le Breton 2020-11-30 17:06:03 +01:00 committed by William Lallemand
parent f67442efdb
commit 8bb72aa82f
2 changed files with 39 additions and 23 deletions

View File

@ -187,8 +187,9 @@ client c1 -connect ${h1_fe_sock} {
expect resp.http.content-type == "text/plain"
expect resp.http.X-Cache-Hit == 1
# The accept-encoding normalizer function sorts alphabeticaly the values
# before calculating the secondary key
# The accept-encoding normalizer function converts the header values
# to lower case then calculates the hash of every sub part before
# sorting the hashes and xor'ing them (while removing duplicates).
txreq -url "/accept-encoding-multiple" -hdr "Accept-Encoding: first,second"
rxresp
expect resp.status == 200
@ -207,6 +208,12 @@ client c1 -connect ${h1_fe_sock} {
expect resp.bodylen == 51
expect resp.http.X-Cache-Hit == 1
txreq -url "/accept-encoding-multiple" -hdr "Accept-Encoding: FirsT,SECOND,first"
rxresp
expect resp.status == 200
expect resp.bodylen == 51
expect resp.http.X-Cache-Hit == 1
# Unmanaged vary
txreq -url "/unmanaged" -hdr "Accept-Encoding: first_value"
rxresp
@ -270,7 +277,7 @@ client c1 -connect ${h1_fe_sock} {
expect resp.bodylen == 57
expect resp.http.X-Cache-Hit == 1
# The following requests are trated by a backend that does not cache
# The following requests are treated by a backend that does not cache
# responses containing a Vary header
txreq -url "/no_vary_support"
rxresp

View File

@ -1791,10 +1791,14 @@ struct flt_ops cache_ops = {
int accept_encoding_cmp(const void *a, const void *b)
{
const struct ist ist_a = *(const struct ist*)a;
const struct ist ist_b = *(const struct ist*)b;
unsigned int int_a = *(unsigned int*)a;
unsigned int int_b = *(unsigned int*)b;
return istdiff(ist_a, ist_b);
if (int_a < int_b)
return -1;
if (int_a > int_b)
return 1;
return 0;
}
#define ACCEPT_ENCODING_MAX_ENTRIES 16
@ -1804,33 +1808,38 @@ int accept_encoding_cmp(const void *a, const void *b)
* for the newly constructed buffer.
* Returns 0 in case of success.
*/
static int accept_encoding_normalizer(struct ist value, char *buf, unsigned int *buf_len)
static int accept_encoding_normalizer(struct ist full_value, char *buf, unsigned int *buf_len)
{
struct ist values[ACCEPT_ENCODING_MAX_ENTRIES] = {{}};
unsigned int values[ACCEPT_ENCODING_MAX_ENTRIES] = {};
size_t count = 0;
char *comma = NULL;
struct buffer *trash = get_trash_chunk();
int hash_value = 0;
unsigned int hash_value = 0;
unsigned int prev = 0, curr = 0;
/* Turn accept-encoding value to lower case */
full_value = ist2bin_lc(istptr(full_value), full_value);
/* The hash will be built out of a sorted list of accepted encodings. */
while (count < (ACCEPT_ENCODING_MAX_ENTRIES - 1) && (comma = istchr(value, ',')) != NULL) {
size_t length = comma - istptr(value);
while (count < (ACCEPT_ENCODING_MAX_ENTRIES - 1) && (comma = istchr(full_value, ',')) != NULL) {
size_t length = comma - istptr(full_value);
values[count++] = hash_crc32(istptr(full_value), length);
full_value = istadv(full_value, length + 1);
values[count++] = isttrim(value, length);
value = istadv(value, length + 1);
}
values[count++] = value;
if (count == ACCEPT_ENCODING_MAX_ENTRIES)
return 1;
values[count++] = hash_crc32(istptr(full_value), istlen(full_value));
/* Sort the values alphabetically. */
qsort(values, count, sizeof(struct ist), &accept_encoding_cmp);
qsort(values, count, sizeof(*values), &accept_encoding_cmp);
while (count)
chunk_istcat(trash, values[--count]);
hash_value = hash_crc32(b_orig(trash), b_data(trash));
while (count) {
curr = values[--count];
if (curr != prev) {
hash_value ^= curr;
}
prev = curr;
}
memcpy(buf, &hash_value, sizeof(hash_value));
*buf_len = sizeof(hash_value);