cfg80211: allow userspace to take ownership of interfaces

When dynamically creating interfaces from userspace, e.g. for P2P usage,
such interfaces are usually owned by the process that created them, i.e.
wpa_supplicant. Should wpa_supplicant crash, such interfaces will often
cease operating properly and cause problems on restarting the process.

To avoid this problem, introduce an ownership concept for interfaces. If
an interface is owned by a netlink socket, then it will be destroyed if
the netlink socket is closed for any reason, including if the process it
belongs to crashed. This gives us a race-free way to get rid of any such
interfaces.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/net/wireless/core.h b/net/wireless/core.h
index 5b1fdca..6f6f756 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -80,6 +80,10 @@ struct cfg80211_registered_device {
 
 	struct cfg80211_coalesce *coalesce;
 
+	spinlock_t destroy_list_lock;
+	struct list_head destroy_list;
+	struct work_struct destroy_work;
+
 	/* must be last because of the way we do wiphy_priv(),
 	 * and it should at least be aligned to NETDEV_ALIGN */
 	struct wiphy wiphy __aligned(NETDEV_ALIGN);
@@ -232,6 +236,13 @@ struct cfg80211_beacon_registration {
 	u32 nlportid;
 };
 
+struct cfg80211_iface_destroy {
+	struct list_head list;
+	u32 nlportid;
+};
+
+void cfg80211_destroy_ifaces(struct cfg80211_registered_device *rdev);
+
 /* free object */
 void cfg80211_dev_free(struct cfg80211_registered_device *rdev);