mac80211: fix allmulti/promisc behaviour

When an interface with promisc/allmulti bit is taken down,
the mac80211 state can become confused. This fixes it by
making mac80211 keep track of all *active* interfaces that
have the promisc/allmulti bit set in the sdata, we sync
the interface bit into sdata at set_multicast_list() time
so this works.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index c38e2cd4f7a7..59350b8727ec 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -267,6 +267,17 @@ static int ieee80211_open(struct net_device *dev)
                 tasklet_enable(&local->tasklet);
         }
 
+        /*
+         * set_multicast_list will be invoked by the networking core
+         * which will check whether any increments here were done in
+         * error and sync them down to the hardware as filter flags.
+         */
+        if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
+                atomic_inc(&local->iff_allmultis);
+
+        if (sdata->flags & IEEE80211_SDATA_PROMISC)
+                atomic_inc(&local->iff_promiscs);
+
         local->open_count++;
 
         netif_start_queue(dev);
@@ -284,6 +295,18 @@ static int ieee80211_stop(struct net_device *dev)
 
         netif_stop_queue(dev);
 
+        /*
+         * Don't count this interface for promisc/allmulti while it
+         * is down. dev_mc_unsync() will invoke set_multicast_list
+         * on the master interface which will sync these down to the
+         * hardware as filter flags.
+         */
+        if (sdata->flags & IEEE80211_SDATA_ALLMULTI)
+                atomic_dec(&local->iff_allmultis);
+
+        if (sdata->flags & IEEE80211_SDATA_PROMISC)
+                atomic_dec(&local->iff_promiscs);
+
         dev_mc_unsync(local->mdev, dev);
 
         /* down all dependent devices, that is VLANs */