netfilter: nf_tables: split set destruction in deactivate and destroy phase

Splits unbind_set into destroy_set and unbinding operation.

Unbinding removes set from lists (so new transaction would not
find it anymore) but keeps memory allocated (so packet path continues
to work).

Rebind function is added to allow unrolling in case transaction
that wants to remove set is aborted.

Destroy function is added to free the memory, but this could occur
outside of transaction in the future.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 25 insertions, 11 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 2cfb173cd0b2..220e6aab3fac 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -298,7 +298,7 @@ static int nft_delrule_by_chain(struct nft_ctx *ctx)
 	return 0;
 }
 
-static int nft_trans_set_add(struct nft_ctx *ctx, int msg_type,
+static int nft_trans_set_add(const struct nft_ctx *ctx, int msg_type,
 			     struct nft_set *set)
 {
 	struct nft_trans *trans;
@@ -318,7 +318,7 @@ static int nft_trans_set_add(struct nft_ctx *ctx, int msg_type,
 	return 0;
 }
 
-static int nft_delset(struct nft_ctx *ctx, struct nft_set *set)
+static int nft_delset(const struct nft_ctx *ctx, struct nft_set *set)
 {
 	int err;
 
@@ -3567,13 +3567,6 @@ static void nft_set_destroy(struct nft_set *set)
 	kvfree(set);
 }
 
-static void nf_tables_set_destroy(const struct nft_ctx *ctx, struct nft_set *set)
-{
-	list_del_rcu(&set->list);
-	nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_ATOMIC);
-	nft_set_destroy(set);
-}
-
 static int nf_tables_delset(struct net *net, struct sock *nlsk,
 			    struct sk_buff *skb, const struct nlmsghdr *nlh,
 			    const struct nlattr * const nla[],
@@ -3668,17 +3661,38 @@ bind:
 }
 EXPORT_SYMBOL_GPL(nf_tables_bind_set);
 
-void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
+void nf_tables_rebind_set(const struct nft_ctx *ctx, struct nft_set *set,
 			  struct nft_set_binding *binding)
 {
+	if (list_empty(&set->bindings) && nft_set_is_anonymous(set) &&
+	    nft_is_active(ctx->net, set))
+		list_add_tail_rcu(&set->list, &ctx->table->sets);
+
+	list_add_tail_rcu(&binding->list, &set->bindings);
+}
+EXPORT_SYMBOL_GPL(nf_tables_rebind_set);
+
+void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
+		          struct nft_set_binding *binding)
+{
 	list_del_rcu(&binding->list);
 
 	if (list_empty(&set->bindings) && nft_set_is_anonymous(set) &&
 	    nft_is_active(ctx->net, set))
-		nf_tables_set_destroy(ctx, set);
+		list_del_rcu(&set->list);
 }
 EXPORT_SYMBOL_GPL(nf_tables_unbind_set);
 
+void nf_tables_destroy_set(const struct nft_ctx *ctx, struct nft_set *set)
+{
+	if (list_empty(&set->bindings) && nft_set_is_anonymous(set) &&
+	    nft_is_active(ctx->net, set)) {
+		nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_ATOMIC);
+		nft_set_destroy(set);
+	}
+}
+EXPORT_SYMBOL_GPL(nf_tables_destroy_set);
+
 const struct nft_set_ext_type nft_set_ext_types[] = {
 	[NFT_SET_EXT_KEY]		= {
 		.align	= __alignof__(u32),