[PATCH nft 4/4] src: allow flowtable definitions with no devices

[Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>]

 # nft add flowtable x y { hook ingress priority 0\; }

The listing shows no devices:

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

Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
 src/mnl.c  | 10 ++++++----
 src/rule.c | 14 ++++++++------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/mnl.c b/src/mnl.c
index 759ae41ceb01..19f666416909 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);
diff --git a/src/rule.c b/src/rule.c
index 1f56faeb5c3c..21a52157391d 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -2272,13 +2272,15 @@ static void flowtable_print_declaration(const struct flowtable *flowtable,
 			   flowtable->hook.num, flowtable->priority.expr),
 		  opts->stmt_separator);
 
-	nft_print(octx, "%s%sdevices = { ", opts->tab, opts->tab);
-	for (i = 0; i < flowtable->dev_array_len; i++) {
-		nft_print(octx, "%s", flowtable->dev_array[i]);
-		if (i + 1 != flowtable->dev_array_len)
-			nft_print(octx, ", ");
+	if (flowtable->dev_array_len > 0) {
+		nft_print(octx, "%s%sdevices = { ", opts->tab, opts->tab);
+		for (i = 0; i < flowtable->dev_array_len; i++) {
+			nft_print(octx, "%s", flowtable->dev_array[i]);
+			if (i + 1 != flowtable->dev_array_len)
+				nft_print(octx, ", ");
+		}
+		nft_print(octx, " }%s", opts->stmt_separator);
 	}
-	nft_print(octx, " }%s", opts->stmt_separator);
 
 	if (flowtable->flags & NFT_FLOWTABLE_COUNTER)
 		nft_print(octx, "%s%scounter%s", opts->tab, opts->tab,
-- 
2.20.1