netfilter: nftables: add loop check helper function

This patch adds nft_check_loops() to reuse it in the new catch-all
element codebase.

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

net/netfilter/nf_tables_api.c

@@ -8626,26 +8626,38 @@ EXPORT_SYMBOL_GPL(nft_chain_validate_hooks);
 static int nf_tables_check_loops(const struct nft_ctx *ctx,
 				 const struct nft_chain *chain);
 
+static int nft_check_loops(const struct nft_ctx *ctx,
+			   const struct nft_set_ext *ext)
+{
+	const struct nft_data *data;
+	int ret;
+
+	data = nft_set_ext_data(ext);
+	switch (data->verdict.code) {
+	case NFT_JUMP:
+	case NFT_GOTO:
+		ret = nf_tables_check_loops(ctx, data->verdict.chain);
+		break;
+	default:
+		ret = 0;
+		break;
+	}
+
+	return ret;
+}
+
 static int nf_tables_loop_check_setelem(const struct nft_ctx *ctx,
 					struct nft_set *set,
 					const struct nft_set_iter *iter,
 					struct nft_set_elem *elem)
 {
 	const struct nft_set_ext *ext = nft_set_elem_ext(set, elem->priv);
-	const struct nft_data *data;
 
 	if (nft_set_ext_exists(ext, NFT_SET_EXT_FLAGS) &&
 	    *nft_set_ext_flags(ext) & NFT_SET_ELEM_INTERVAL_END)
 		return 0;
 
-	data = nft_set_ext_data(ext);
-	switch (data->verdict.code) {
-	case NFT_JUMP:
-	case NFT_GOTO:
-		return nf_tables_check_loops(ctx, data->verdict.chain);
-	default:
-		return 0;
-	}
+	return nft_check_loops(ctx, ext);
 }
 
 static int nf_tables_check_loops(const struct nft_ctx *ctx,