MEDIUM: cache: store sha1 for hashing the cache key
The cache was relying on the txn->uri for creating its key, which was a
big problem when there was no log activated.
This patch does a sha1 of the host + uri, and stores it in the txn.
When a object is stored, the eb32node uses the first 32 bits of the hash
as a key, and the whole hash is stored in the cache entry.
During a lookup, the truncated hash is used, and when it matches an
entry we check the real sha1.
diff --git a/include/types/proto_http.h b/include/types/proto_http.h
index cf0fdb6..9de1410 100644
--- a/include/types/proto_http.h
+++ b/include/types/proto_http.h
@@ -319,6 +319,7 @@
/* 1 unused byte here */
short status; /* HTTP status from the server, negative if from proxy */
+ char cache_hash[20]; /* Store the cache hash */
char *uri; /* first line if log needed, NULL otherwise */
char *cli_cookie; /* cookie presented by the client, in capture mode */
char *srv_cookie; /* cookie presented by the server, in capture mode */
diff --git a/src/cache.c b/src/cache.c
index 3491015..87c1da7 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -11,6 +11,7 @@
*/
#include <eb32tree.h>
+#include <import/sha1.h>
#include <types/action.h>
#include <types/cli.h>
@@ -63,6 +64,7 @@
unsigned int latest_validation; /* latest validation date */
unsigned int expire; /* expiration date */
struct eb32_node eb; /* ebtree node used to hold the cache object */
+ char hash[20];
unsigned char data[0];
};
@@ -71,16 +73,21 @@
static struct list caches = LIST_HEAD_INIT(caches);
static struct cache *tmp_cache_config = NULL;
-struct cache_entry *entry_exist(struct cache *cache, struct cache_entry *new_entry)
+struct cache_entry *entry_exist(struct cache *cache, char *hash)
{
struct eb32_node *node;
struct cache_entry *entry;
- node = eb32_lookup(&cache->entries, new_entry->eb.key);
+ node = eb32_lookup(&cache->entries, (*(unsigned int *)hash));
if (!node)
return NULL;
entry = eb32_entry(node, struct cache_entry, eb);
+
+ /* if that's not the right node */
+ if (memcmp(entry->hash, hash, sizeof(entry->hash)))
+ return NULL;
+
if (entry->expire > now.tv_sec) {
return entry;
} else {
@@ -443,11 +450,12 @@
cache_ctx->first_block = first;
object = (struct cache_entry *)first->data;
- object->eb.key = hash_djb2(txn->uri, strlen(txn->uri));
+ object->eb.key = (*(unsigned int *)&txn->cache_hash);
+ memcpy(object->hash, txn->cache_hash, sizeof(object->hash));
/* Insert the node later on caching success */
shctx_lock(shctx);
- if (entry_exist((struct cache *)rule->arg.act.p[0], object)) {
+ if (entry_exist((struct cache *)rule->arg.act.p[0], txn->cache_hash)) {
shctx_unlock(shctx);
if (filter->ctx) {
object->eb.key = 0;
@@ -592,19 +600,53 @@
return ACT_RET_PRS_ERR;
}
+/* This produces a sha1 hash of the concatenation of the first
+ * occurrence of the Host header followed by the path component if it
+ * begins with a slash ('/'). */
+int sha1_hosturi(struct http_txn *txn)
+{
+ struct hdr_ctx ctx;
+
+ blk_SHA_CTX sha1_ctx;
+ struct chunk *trash;
+ char *path;
+ char *end;
+ trash = get_trash_chunk();
+
+ /* retrive the host */
+ ctx.idx = 0;
+ if (!http_find_header2("Host", 4, txn->req.chn->buf->p, &txn->hdr_idx, &ctx))
+ return 0;
+ chunk_strncat(trash, ctx.line + ctx.val, ctx.vlen);
+
+ /* now retrieve the path */
+ end = txn->req.chn->buf->p + txn->req.sl.rq.u + txn->req.sl.rq.u_l;
+ path = http_get_path(txn);
+ if (!path)
+ return 0;
+ chunk_strncat(trash, path, end - path);
+
+ /* hash everything */
+ blk_SHA1_Init(&sha1_ctx);
+ blk_SHA1_Update(&sha1_ctx, trash->str, trash->len);
+ blk_SHA1_Final((unsigned char *)txn->cache_hash, &sha1_ctx);
+
+ return 1;
+}
+
+
enum act_return http_action_req_cache_use(struct act_rule *rule, struct proxy *px,
struct session *sess, struct stream *s, int flags)
{
- struct cache_entry search_entry;
struct cache_entry *res;
-
struct cache *cache = (struct cache *)rule->arg.act.p[0];
- search_entry.eb.key = hash_djb2(s->txn->uri, strlen(s->txn->uri));
+ sha1_hosturi(s->txn);
+
shctx_lock(shctx_ptr(cache));
- res = entry_exist(cache, &search_entry);
+ res = entry_exist(cache, s->txn->cache_hash);
if (res) {
struct appctx *appctx;
shctx_row_inc_hot(shctx_ptr(cache), block_ptr(res));
@@ -900,7 +942,7 @@
}
entry = container_of(node, struct cache_entry, eb);
- chunk_appendf(&trash, "%p (size: %u (%u blocks), refcount:%u, expire: %d)\n", entry, block_ptr(entry)->len, block_ptr(entry)->block_count, block_ptr(entry)->refcount, entry->expire - (int)now.tv_sec);
+ chunk_appendf(&trash, "%p hash:%u size:%u (%u blocks), refcount:%u, expire:%d\n", entry, (*(unsigned int *)entry->hash), block_ptr(entry)->len, block_ptr(entry)->block_count, block_ptr(entry)->refcount, entry->expire - (int)now.tv_sec);
next_key = node->key + 1;
appctx->ctx.cli.i0 = next_key;