netfilter: nft_set_hash: add lookup variant for fixed size hashtable

This patch provides a faster variant of the lookup function for 2 and 4
byte keys. Optimizing the one byte case is not worth, as the set backend
selection will always select the bitmap set type for such case.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2017-05-22 17:48:09 +01:00
parent 6c03ae210c
commit 446a8268b7
1 changed files with 58 additions and 2 deletions

View File

@ -409,6 +409,38 @@ static bool nft_hash_lookup(const struct net *net, const struct nft_set *set,
return false;
}
/* nft_hash_select_ops() makes sure key size can be either 2 or 4 bytes . */
static inline u32 nft_hash_key(const u32 *key, u32 klen)
{
if (klen == 4)
return *key;
return *(u16 *)key;
}
static bool nft_hash_lookup_fast(const struct net *net,
const struct nft_set *set,
const u32 *key, const struct nft_set_ext **ext)
{
struct nft_hash *priv = nft_set_priv(set);
u8 genmask = nft_genmask_cur(net);
const struct nft_hash_elem *he;
u32 hash, k1, k2;
k1 = nft_hash_key(key, set->klen);
hash = jhash_1word(k1, priv->seed);
hash = reciprocal_scale(hash, priv->buckets);
hlist_for_each_entry_rcu(he, &priv->table[hash], node) {
k2 = nft_hash_key(nft_set_ext_key(&he->ext)->data, set->klen);
if (k1 == k2 &&
nft_set_elem_active(&he->ext, genmask)) {
*ext = &he->ext;
return true;
}
}
return false;
}
static int nft_hash_insert(const struct net *net, const struct nft_set *set,
const struct nft_set_elem *elem,
struct nft_set_ext **ext)
@ -588,12 +620,36 @@ static struct nft_set_ops nft_hash_ops __read_mostly = {
.features = NFT_SET_MAP | NFT_SET_OBJECT,
};
static struct nft_set_ops nft_hash_fast_ops __read_mostly = {
.type = &nft_hash_type,
.privsize = nft_hash_privsize,
.elemsize = offsetof(struct nft_hash_elem, ext),
.estimate = nft_hash_estimate,
.init = nft_hash_init,
.destroy = nft_hash_destroy,
.insert = nft_hash_insert,
.activate = nft_hash_activate,
.deactivate = nft_hash_deactivate,
.flush = nft_hash_flush,
.remove = nft_hash_remove,
.lookup = nft_hash_lookup_fast,
.walk = nft_hash_walk,
.features = NFT_SET_MAP | NFT_SET_OBJECT,
};
static const struct nft_set_ops *
nft_hash_select_ops(const struct nft_ctx *ctx, const struct nft_set_desc *desc,
u32 flags)
{
if (desc->size)
return &nft_hash_ops;
if (desc->size) {
switch (desc->klen) {
case 2:
case 4:
return &nft_hash_fast_ops;
default:
return &nft_hash_ops;
}
}
return &nft_rhash_ops;
}