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Commit 446a8268 authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso
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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: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 6c03ae21

net/netfilter/nft_set_hash.c

+58 −2
Original line number Diff line number Diff line
@@ -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)

	if (desc->size) {

		switch (desc->klen) {

		case 2:

		case 4:

			return &nft_hash_fast_ops;

		default:

			return &nft_hash_ops;

		}

	}



	return &nft_rhash_ops;

}