mac80211: filter multicast data packets on AP / AP_VLAN

This patch adds filtering for multicast data packets on AP_VLAN
interfaces that have no authorized station connected and changes
filtering on AP interfaces to not count stations assigned to
AP_VLAN interfaces.

This saves airtime and avoids waking up other stations currently
authorized in this BSS. When using WPA, the packets dropped could
not be decrypted by any station.

The behaviour when there are no AP_VLAN interfaces is left unchanged.

When there are AP_VLAN interfaces, this patch
1. adds filtering multicast data packets sent on AP_VLAN interfaces
   that have no authorized station connected.
   No filtering happens on 4addr AP_VLAN interfaces.
2. makes filtering of multicast data packets sent on AP interfaces
   depend on the number of authorized stations in this bss not
   assigned to an AP_VLAN interface.

Therefore, a new num_mcast_sta counter is added for AP_VLAN interfaces.
The existing one for AP interfaces is altered to not track stations
assigned to an AP_VLAN interface.

The new counter is exposed in debugfs.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
[reformat commit message a bit, unline ieee80211_vif_{inc,dec}_num_mcast]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index bcec1240f41d..1a05f85cb1f0 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -477,6 +477,7 @@ IEEE80211_IF_FILE_RW(tdls_wider_bw);
 IEEE80211_IF_FILE(num_mcast_sta, u.ap.num_mcast_sta, ATOMIC);
 IEEE80211_IF_FILE(num_sta_ps, u.ap.ps.num_sta_ps, ATOMIC);
 IEEE80211_IF_FILE(dtim_count, u.ap.ps.dtim_count, DEC);
+IEEE80211_IF_FILE(num_mcast_sta_vlan, u.vlan.num_mcast_sta, ATOMIC);
 
 static ssize_t ieee80211_if_fmt_num_buffered_multicast(
 	const struct ieee80211_sub_if_data *sdata, char *buf, int buflen)
@@ -684,6 +685,13 @@ static void add_ap_files(struct ieee80211_sub_if_data *sdata)
 	DEBUGFS_ADD_MODE(tkip_mic_test, 0200);
 }
 
+static void add_vlan_files(struct ieee80211_sub_if_data *sdata)
+{
+	/* add num_mcast_sta_vlan using name num_mcast_sta */
+	debugfs_create_file("num_mcast_sta", 0400, sdata->vif.debugfs_dir,
+			    sdata, &num_mcast_sta_vlan_ops);
+}
+
 static void add_ibss_files(struct ieee80211_sub_if_data *sdata)
 {
 	DEBUGFS_ADD_MODE(tsf, 0600);
@@ -787,6 +795,9 @@ static void add_files(struct ieee80211_sub_if_data *sdata)
 	case NL80211_IFTYPE_AP:
 		add_ap_files(sdata);
 		break;
+	case NL80211_IFTYPE_AP_VLAN:
+		add_vlan_files(sdata);
+		break;
 	case NL80211_IFTYPE_WDS:
 		add_wds_files(sdata);
 		break;