netfilter: nftables: add nft_parse_register_store() and use it

This new function combines the netlink register attribute parser
and the store validation function.

This update requires to replace:

        enum nft_registers      dreg:8;

in many of the expression private areas otherwise compiler complains
with:

        error: cannot take address of bit-field ‘dreg’

when passing the register field as reference.

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

1 files changed, 29 insertions, 5 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 1e82ebba230d..c23163ffb5a1 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4438,6 +4438,12 @@ static int nf_tables_delset(struct net *net, struct sock *nlsk,
 	return nft_delset(&ctx, set);
 }
 
+static int nft_validate_register_store(const struct nft_ctx *ctx,
+				       enum nft_registers reg,
+				       const struct nft_data *data,
+				       enum nft_data_types type,
+				       unsigned int len);
+
 static int nf_tables_bind_check_setelem(const struct nft_ctx *ctx,
 					struct nft_set *set,
 					const struct nft_set_iter *iter,
@@ -8675,10 +8681,11 @@ EXPORT_SYMBOL_GPL(nft_parse_register_load);
  * 	A value of NULL for the data means that its runtime gathered
  * 	data.
  */
-int nft_validate_register_store(const struct nft_ctx *ctx,
-				enum nft_registers reg,
-				const struct nft_data *data,
-				enum nft_data_types type, unsigned int len)
+static int nft_validate_register_store(const struct nft_ctx *ctx,
+				       enum nft_registers reg,
+				       const struct nft_data *data,
+				       enum nft_data_types type,
+				       unsigned int len)
 {
 	int err;
 
@@ -8710,7 +8717,24 @@ int nft_validate_register_store(const struct nft_ctx *ctx,
 		return 0;
 	}
 }
-EXPORT_SYMBOL_GPL(nft_validate_register_store);
+
+int nft_parse_register_store(const struct nft_ctx *ctx,
+			     const struct nlattr *attr, u8 *dreg,
+			     const struct nft_data *data,
+			     enum nft_data_types type, unsigned int len)
+{
+	int err;
+	u32 reg;
+
+	reg = nft_parse_register(attr);
+	err = nft_validate_register_store(ctx, reg, data, type, len);
+	if (err < 0)
+		return err;
+
+	*dreg = reg;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nft_parse_register_store);
 
 static const struct nla_policy nft_verdict_policy[NFTA_VERDICT_MAX + 1] = {
 	[NFTA_VERDICT_CODE]	= { .type = NLA_U32 },