src: allow flowtable definitions with no devices

The listing shows no devices:

 # nft list ruleset
 table ip x {
        flowtable y {
                hook ingress priority filter
        }
 }

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

1 files changed, 6 insertions, 4 deletions

diff --git a/src/mnl.c b/src/mnl.c
index 759ae41c..19f66641 100644
--- a/src/mnl.c
+++ b/src/mnl.c
@@ -1652,10 +1652,12 @@ int mnl_nft_flowtable_add(struct netlink_ctx *ctx, struct cmd *cmd,
 		nftnl_flowtable_set_u32(flo, NFTNL_FLOWTABLE_PRIO, 0);
 	}
 
-	dev_array = nft_flowtable_dev_array(cmd);
-	nftnl_flowtable_set_data(flo, NFTNL_FLOWTABLE_DEVICES,
-				 dev_array, 0);
-	nft_flowtable_dev_array_free(dev_array);
+	if (cmd->flowtable->dev_expr) {
+		dev_array = nft_flowtable_dev_array(cmd);
+		nftnl_flowtable_set_data(flo, NFTNL_FLOWTABLE_DEVICES,
+					 dev_array, 0);
+		nft_flowtable_dev_array_free(dev_array);
+	}
 
 	nftnl_flowtable_set_u32(flo, NFTNL_FLOWTABLE_FLAGS,
 				cmd->flowtable->flags);