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 <or...@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;
--
1.7.12
