netfilter: nf_tables: expression ops overloading

Split the expression ops into two parts and support overloading of
the runtime expression ops based on the requested function through
a ->select_ops() callback.

This can be used to provide optimized implementations, for instance
for loading small aligned amounts of data from the packet or inlining
frequently used operations into the main evaluation loop.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 11 insertions, 5 deletions

diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 21c6a6b..8e0bb75 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -98,25 +98,31 @@ nla_put_failure:
 	return -1;
 }
 
-static struct nft_expr_ops exthdr_ops __read_mostly = {
-	.name		= "exthdr",
+static struct nft_expr_type nft_exthdr_type;
+static const struct nft_expr_ops nft_exthdr_ops = {
+	.type		= &nft_exthdr_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_exthdr)),
-	.owner		= THIS_MODULE,
 	.eval		= nft_exthdr_eval,
 	.init		= nft_exthdr_init,
 	.dump		= nft_exthdr_dump,
+};
+
+static struct nft_expr_type nft_exthdr_type __read_mostly = {
+	.name		= "exthdr",
+	.ops		= &nft_exthdr_ops,
 	.policy		= nft_exthdr_policy,
 	.maxattr	= NFTA_EXTHDR_MAX,
+	.owner		= THIS_MODULE,
 };
 
 static int __init nft_exthdr_module_init(void)
 {
-	return nft_register_expr(&exthdr_ops);
+	return nft_register_expr(&nft_exthdr_type);
 }
 
 static void __exit nft_exthdr_module_exit(void)
 {
-	nft_unregister_expr(&exthdr_ops);
+	nft_unregister_expr(&nft_exthdr_type);
 }
 
 module_init(nft_exthdr_module_init);