Any virtual device created on top of a batman-adv mesh interface must be prevented to be used to create a new mesh network (this would lead to an unwanted batman-over-batman configuration)

Signed-off-by: Antonio Quartulli ordex@autistici.org ---

v2: - added check for !parent_dev with WARN_ON()

hard-interface.c | 41 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/hard-interface.c b/hard-interface.c index fab9e41..7967f14 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -58,6 +58,45 @@ out: 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) @@ -70,7 +109,7 @@ static int batadv_is_valid_iface(const struct net_device *net_dev) 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;