netfilter: nf_tables: add nft_set_lookup()

This new function consolidates set lookup via either name or ID by
introducing a new nft_set_lookup() function. Replace existing spots
where we can use this too.

Signed-off-by: Pablo Neira Ayuso <[e-mail]>

include/net/netfilter/nf_tables.h

···
 	return (void *)priv - offsetof(struct nft_set, data);
 }
 
-struct nft_set *nf_tables_set_lookup(const struct nft_table *table,
-				     const struct nlattr *nla, u8 genmask);
-struct nft_set *nf_tables_set_lookup_byid(const struct net *net,
-					  const struct nlattr *nla, u8 genmask);
+struct nft_set *nft_set_lookup(const struct net *net,
+			       const struct nft_table *table,
+			       const struct nlattr *nla_set_name,
+			       const struct nlattr *nla_set_id,
+			       u8 genmask);
 
 static inline unsigned long nft_set_gc_interval(const struct nft_set *set)
 {

net/netfilter/nf_tables_api.c

···
 	return 0;
 }
 
-struct nft_set *nf_tables_set_lookup(const struct nft_table *table,
-				     const struct nlattr *nla, u8 genmask)
+static struct nft_set *nf_tables_set_lookup(const struct nft_table *table,
+					    const struct nlattr *nla, u8 genmask)
 {
 	struct nft_set *set;
 
···
 	}
 	return ERR_PTR(-ENOENT);
 }
-EXPORT_SYMBOL_GPL(nf_tables_set_lookup);
 
-struct nft_set *nf_tables_set_lookup_byid(const struct net *net,
-					  const struct nlattr *nla,
-					  u8 genmask)
+static struct nft_set *nf_tables_set_lookup_byid(const struct net *net,
+						 const struct nlattr *nla,
+						 u8 genmask)
 {
 	struct nft_trans *trans;
 	u32 id = ntohl(nla_get_be32(nla));
···
 	}
 	return ERR_PTR(-ENOENT);
 }
-EXPORT_SYMBOL_GPL(nf_tables_set_lookup_byid);
+
+struct nft_set *nft_set_lookup(const struct net *net,
+			       const struct nft_table *table,
+			       const struct nlattr *nla_set_name,
+			       const struct nlattr *nla_set_id,
+			       u8 genmask)
+{
+	struct nft_set *set;
+
+	set = nf_tables_set_lookup(table, nla_set_name, genmask);
+	if (IS_ERR(set)) {
+		if (!nla_set_id)
+			return set;
+
+		set = nf_tables_set_lookup_byid(net, nla_set_id, genmask);
+	}
+	return set;
+}
+EXPORT_SYMBOL_GPL(nft_set_lookup);
 
 static int nf_tables_set_alloc_name(struct nft_ctx *ctx, struct nft_set *set,
 				    const char *name)

net/netfilter/nft_dynset.c

···
 			priv->invert = true;
 	}
 
-	set = nf_tables_set_lookup(ctx->table, tb[NFTA_DYNSET_SET_NAME],
-				   genmask);
-	if (IS_ERR(set)) {
-		if (tb[NFTA_DYNSET_SET_ID])
-			set = nf_tables_set_lookup_byid(ctx->net,
-							tb[NFTA_DYNSET_SET_ID],
-							genmask);
-		if (IS_ERR(set))
-			return PTR_ERR(set);
-	}
+	set = nft_set_lookup(ctx->net, ctx->table, tb[NFTA_DYNSET_SET_NAME],
+			     tb[NFTA_DYNSET_SET_ID], genmask);
+	if (IS_ERR(set))
+		return PTR_ERR(set);
 
 	if (set->ops->update == NULL)
 		return -EOPNOTSUPP;

net/netfilter/nft_lookup.c

···
 	    tb[NFTA_LOOKUP_SREG] == NULL)
 		return -EINVAL;
 
-	set = nf_tables_set_lookup(ctx->table, tb[NFTA_LOOKUP_SET], genmask);
-	if (IS_ERR(set)) {
-		if (tb[NFTA_LOOKUP_SET_ID]) {
-			set = nf_tables_set_lookup_byid(ctx->net,
-							tb[NFTA_LOOKUP_SET_ID],
-							genmask);
-		}
-		if (IS_ERR(set))
-			return PTR_ERR(set);
-	}
+	set = nft_set_lookup(ctx->net, ctx->table, tb[NFTA_LOOKUP_SET],
+			     tb[NFTA_LOOKUP_SET_ID], genmask);
+	if (IS_ERR(set))
+		return PTR_ERR(set);
 
 	if (set->flags & NFT_SET_EVAL)
 		return -EOPNOTSUPP;

net/netfilter/nft_objref.c

···
 	struct nft_set *set;
 	int err;
 
-	set = nf_tables_set_lookup(ctx->table, tb[NFTA_OBJREF_SET_NAME], genmask);
-	if (IS_ERR(set)) {
-		if (tb[NFTA_OBJREF_SET_ID]) {
-			set = nf_tables_set_lookup_byid(ctx->net,
-							tb[NFTA_OBJREF_SET_ID],
-							genmask);
-		}
-		if (IS_ERR(set))
-			return PTR_ERR(set);
-	}
+	set = nft_set_lookup(ctx->net, ctx->table, tb[NFTA_OBJREF_SET_NAME],
+			     tb[NFTA_OBJREF_SET_ID], genmask);
+	if (IS_ERR(set))
+		return PTR_ERR(set);
 
 	if (!(set->flags & NFT_SET_OBJECT))
 		return -EINVAL;