int (*get_ifindex)(const struct netdev *netdev);
/* Sets 'carrier' to true if carrier is active (link light is on) on
- * 'netdev'. */
+ * 'netdev'.
+ *
+ * May be null if device does not provide carrier status (will be always
+ * up as long as device is up).
+ */
int (*get_carrier)(const struct netdev *netdev, bool *carrier);
/* Retrieves current device stats for 'netdev' into 'stats'.