batman-adv: prevent using any virtual device created on batman-adv as hard-interface

	return hard_iface;

}

/**

 * batadv_is_on_batman_iface - check if a device is a batman iface descendant

 * @net_dev: the device to check

 *

 * If the user creates any virtual device on top of a batman-adv interface, it

 * is important to prevent this new interface to be used to create a new mesh

 * network (this behaviour would lead to a batman-over-batman configuration).

 * This function recursively checks all the fathers of the device passed as

 * argument looking for a batman-adv soft interface.

 *

 * Returns true if the device is descendant of a batman-adv mesh interface (or

 * if it is a batman-adv interface itself), false otherwise

 */

static bool batadv_is_on_batman_iface(const struct net_device *net_dev)

{

	struct net_device *parent_dev;

	bool ret;

	/* check if this is a batman-adv mesh interface */

	if (batadv_softif_is_valid(net_dev))

		return true;

	/* no more parents..stop recursion */

	if (net_dev->iflink == net_dev->ifindex)

		return false;

	/* recurse over the parent device */

	parent_dev = dev_get_by_index(&init_net, net_dev->iflink);

	/* if we got a NULL parent_dev there is something broken.. */

	if (WARN(!parent_dev, "Cannot find parent device"))

		return false;

	ret = batadv_is_on_batman_iface(parent_dev);

	if (parent_dev)

		dev_put(parent_dev);

	return ret;

}

static int batadv_is_valid_iface(const struct net_device *net_dev)

{

	if (net_dev->flags & IFF_LOOPBACK)

		return 0;

	/* no batman over batman */

	if (batadv_softif_is_valid(net_dev))

	if (batadv_is_on_batman_iface(net_dev))

		return 0;

	return 1;