netlink: quick sort array of devices

Provide an ordered list of devices for (netdev) chain and flowtable.

Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1525
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/netlink.c b/src/netlink.c
index 6b6fe277..e91b06e3 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -517,6 +517,14 @@ static int chain_parse_udata_cb(const struct nftnl_udata *attr, void *data)
 	return 0;
 }
 
+static int qsort_device_cmp(const void *a, const void *b)
+{
+	const char **x = (const char **)a;
+	const char **y = (const char **)b;
+
+	return strcmp(*x, *y);
+}
+
 struct chain *netlink_delinearize_chain(struct netlink_ctx *ctx,
 					const struct nftnl_chain *nlc)
 {
@@ -580,6 +588,11 @@ struct chain *netlink_delinearize_chain(struct netlink_ctx *ctx,
 			chain->dev_array_len = len;
 		}
 		chain->flags        |= CHAIN_F_BASECHAIN;
+
+		if (chain->dev_array_len) {
+			qsort(chain->dev_array, chain->dev_array_len,
+			      sizeof(char *), qsort_device_cmp);
+		}
 	}
 
 	if (nftnl_chain_is_set(nlc, NFTNL_CHAIN_USERDATA)) {
@@ -1582,6 +1595,11 @@ netlink_delinearize_flowtable(struct netlink_ctx *ctx,
 
 	flowtable->dev_array_len = len;
 
+	if (flowtable->dev_array_len) {
+		qsort(flowtable->dev_array, flowtable->dev_array_len,
+		      sizeof(char *), qsort_device_cmp);
+	}
+
 	priority = nftnl_flowtable_get_u32(nlo, NFTNL_FLOWTABLE_PRIO);
 	flowtable->priority.expr =
 				constant_expr_alloc(&netlink_location,