netfilter: annotate nf_tables base hook ops

This will allow a followup patch to treat the 'ops->priv' pointer
as nft_chain argument without having to first walk the table/chains
to check if there is a matching base chain pointer.

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

include/linux/netfilter.h

@@ -77,12 +77,18 @@ struct nf_hook_state {
 typedef unsigned int nf_hookfn(void *priv,
 			       struct sk_buff *skb,
 			       const struct nf_hook_state *state);
+enum nf_hook_ops_type {
+	NF_HOOK_OP_UNDEFINED,
+	NF_HOOK_OP_NF_TABLES,
+};
+
 struct nf_hook_ops {
 	/* User fills in from here down. */
 	nf_hookfn		*hook;
 	struct net_device	*dev;
 	void			*priv;
-	u_int8_t		pf;
+	u8			pf;
+	enum nf_hook_ops_type	hook_ops_type:8;
 	unsigned int		hooknum;
 	/* Hooks are ordered in ascending priority. */
 	int			priority;

net/netfilter/nf_tables_api.c

@@ -2168,8 +2168,10 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask,
 	}
 
 	nft_trans_chain_policy(trans) = NFT_CHAIN_POLICY_UNSET;
-	if (nft_is_base_chain(chain))
+	if (nft_is_base_chain(chain)) {
+		basechain->ops.hook_ops_type = NF_HOOK_OP_NF_TABLES;
 		nft_trans_chain_policy(trans) = policy;
+	}
 
 	err = nft_chain_add(table, chain);
 	if (err < 0) {