netfilter: nf_tables: select set backend flavour depending on description

This patch adds the infrastructure to support several implementations of
the same set type. This selection will be based on the set description
and the features available for this set. This allow us to select set
backend implementation that will result in better performance numbers.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 36 insertions, 23 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index da314be0c048..c0b2b19607e1 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2377,64 +2377,77 @@ static int nf_tables_delrule(struct net *net, struct sock *nlsk,
  * Sets
  */
 
-static LIST_HEAD(nf_tables_set_ops);
+static LIST_HEAD(nf_tables_set_types);
 
-int nft_register_set(struct nft_set_ops *ops)
+int nft_register_set(struct nft_set_type *type)
 {
 	nfnl_lock(NFNL_SUBSYS_NFTABLES);
-	list_add_tail_rcu(&ops->list, &nf_tables_set_ops);
+	list_add_tail_rcu(&type->list, &nf_tables_set_types);
 	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(nft_register_set);
 
-void nft_unregister_set(struct nft_set_ops *ops)
+void nft_unregister_set(struct nft_set_type *type)
 {
 	nfnl_lock(NFNL_SUBSYS_NFTABLES);
-	list_del_rcu(&ops->list);
+	list_del_rcu(&type->list);
 	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 }
 EXPORT_SYMBOL_GPL(nft_unregister_set);
 
+#define NFT_SET_FEATURES	(NFT_SET_INTERVAL | NFT_SET_MAP | \
+				 NFT_SET_TIMEOUT | NFT_SET_OBJECT)
+
+static bool nft_set_ops_candidate(const struct nft_set_ops *ops, u32 flags)
+{
+	return (flags & ops->features) == (flags & NFT_SET_FEATURES);
+}
+
 /*
  * Select a set implementation based on the data characteristics and the
  * given policy. The total memory use might not be known if no size is
  * given, in that case the amount of memory per element is used.
  */
 static const struct nft_set_ops *
-nft_select_set_ops(const struct nlattr * const nla[],
+nft_select_set_ops(const struct nft_ctx *ctx,
+		   const struct nlattr * const nla[],
 		   const struct nft_set_desc *desc,
 		   enum nft_set_policies policy)
 {
 	const struct nft_set_ops *ops, *bops;
 	struct nft_set_estimate est, best;
-	u32 features;
+	const struct nft_set_type *type;
+	u32 flags = 0;
 
 #ifdef CONFIG_MODULES
-	if (list_empty(&nf_tables_set_ops)) {
+	if (list_empty(&nf_tables_set_types)) {
 		nfnl_unlock(NFNL_SUBSYS_NFTABLES);
 		request_module("nft-set");
 		nfnl_lock(NFNL_SUBSYS_NFTABLES);
-		if (!list_empty(&nf_tables_set_ops))
+		if (!list_empty(&nf_tables_set_types))
 			return ERR_PTR(-EAGAIN);
 	}
 #endif
-	features = 0;
-	if (nla[NFTA_SET_FLAGS] != NULL) {
-		features = ntohl(nla_get_be32(nla[NFTA_SET_FLAGS]));
-		features &= NFT_SET_INTERVAL | NFT_SET_MAP | NFT_SET_TIMEOUT |
-			    NFT_SET_OBJECT;
-	}
+	if (nla[NFTA_SET_FLAGS] != NULL)
+		flags = ntohl(nla_get_be32(nla[NFTA_SET_FLAGS]));
 
 	bops	    = NULL;
 	best.size   = ~0;
 	best.lookup = ~0;
 	best.space  = ~0;
 
-	list_for_each_entry(ops, &nf_tables_set_ops, list) {
-		if ((ops->features & features) != features)
+	list_for_each_entry(type, &nf_tables_set_types, list) {
+		if (!type->select_ops)
+			ops = type->ops;
+		else
+			ops = type->select_ops(ctx, desc, flags);
+		if (!ops)
+			continue;
+
+		if (!nft_set_ops_candidate(ops, flags))
 			continue;
-		if (!ops->estimate(desc, features, &est))
+		if (!ops->estimate(desc, flags, &est))
 			continue;
 
 		switch (policy) {
@@ -2465,10 +2478,10 @@ nft_select_set_ops(const struct nlattr * const nla[],
 			break;
 		}
 
-		if (!try_module_get(ops->owner))
+		if (!try_module_get(type->owner))
 			continue;
 		if (bops != NULL)
-			module_put(bops->owner);
+			module_put(bops->type->owner);
 
 		bops = ops;
 		best = est;
@@ -3029,7 +3042,7 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk,
 	if (!(nlh->nlmsg_flags & NLM_F_CREATE))
 		return -ENOENT;
 
-	ops = nft_select_set_ops(nla, &desc, policy);
+	ops = nft_select_set_ops(&ctx, nla, &desc, policy);
 	if (IS_ERR(ops))
 		return PTR_ERR(ops);
 
@@ -3089,14 +3102,14 @@ err3:
 err2:
 	kfree(set);
 err1:
-	module_put(ops->owner);
+	module_put(ops->type->owner);
 	return err;
 }
 
 static void nft_set_destroy(struct nft_set *set)
 {
 	set->ops->destroy(set);
-	module_put(set->ops->owner);
+	module_put(set->ops->type->owner);
 	kfree(set);
 }