static int dpif_netdev_open(const struct dpif_class *, const char *name,
bool create, struct dpif **);
static int dp_netdev_output_control(struct dp_netdev *, const struct ofpbuf *,
static int dpif_netdev_open(const struct dpif_class *, const char *name,
bool create, struct dpif **);
static int dp_netdev_output_control(struct dp_netdev *, const struct ofpbuf *,