netfilter: nf_tables: add helper functions for expression handling

Add helper functions for initializing, cloning, dumping and destroying
a single expression that is not part of a rule.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index cb42da1011ef..e21623cb7b20 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1,6 +1,7 @@
 #ifndef _NET_NF_TABLES_H
 #define _NET_NF_TABLES_H
 
+#include <linux/module.h>
 #include <linux/list.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nfnetlink.h>
@@ -641,6 +642,18 @@ static inline void *nft_expr_priv(const struct nft_expr *expr)
         return (void *)expr->data;
 }
 
+struct nft_expr *nft_expr_init(const struct nft_ctx *ctx,
+                               const struct nlattr *nla);
+void nft_expr_destroy(const struct nft_ctx *ctx, struct nft_expr *expr);
+int nft_expr_dump(struct sk_buff *skb, unsigned int attr,
+                  const struct nft_expr *expr);
+
+static inline void nft_expr_clone(struct nft_expr *dst, struct nft_expr *src)
+{
+        __module_get(src->ops->type->owner);
+        memcpy(dst, src, src->ops->size);
+}
+
 /**
  *      struct nft_rule - nf_tables rule
  *