mac80211: add support for MU-MIMO air sniffer

add support to MU-MIMO air sniffer according groupID:
in monitor mode, use a given MU-MIMO groupID to monitor stations
that belongs to that group using MU-MIMO.

add support for following a station according to its MAC address
using VHT MU-MIMO sniffer:
the monitors wait until they get an action MU-MIMO notification
frame, then parses it in order to find the groupID that corresponds
to the given MAC address and monitors packets destined to that
groupID using VHT MU-MIMO.

Signed-off-by: Aviya Erenfeld <aviya.erenfeld@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 708c3b1e49a1..6a265aa73a46 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -485,6 +485,9 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
         struct net_device *prev_dev = NULL;
         int present_fcs_len = 0;
         unsigned int rtap_vendor_space = 0;
+        struct ieee80211_mgmt *mgmt;
+        struct ieee80211_sub_if_data *monitor_sdata =
+                rcu_dereference(local->monitor_sdata);
 
         if (unlikely(status->flag & RX_FLAG_RADIOTAP_VENDOR_DATA)) {
                 struct ieee80211_vendor_radiotap *rtap = (void *)origskb->data;
@@ -585,6 +588,23 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
                 ieee80211_rx_stats(sdata->dev, skb->len);
         }
 
+        mgmt = (void *)skb->data;
+        if (monitor_sdata &&
+            skb->len >= IEEE80211_MIN_ACTION_SIZE + 1 + VHT_MUMIMO_GROUPS_DATA_LEN &&
+            ieee80211_is_action(mgmt->frame_control) &&
+            mgmt->u.action.category == WLAN_CATEGORY_VHT &&
+            mgmt->u.action.u.vht_group_notif.action_code == WLAN_VHT_ACTION_GROUPID_MGMT &&
+            is_valid_ether_addr(monitor_sdata->u.mntr.mu_follow_addr) &&
+            ether_addr_equal(mgmt->da, monitor_sdata->u.mntr.mu_follow_addr)) {
+                struct sk_buff *mu_skb = skb_copy(skb, GFP_ATOMIC);
+
+                if (mu_skb) {
+                        mu_skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
+                        skb_queue_tail(&monitor_sdata->skb_queue, mu_skb);
+                        ieee80211_queue_work(&local->hw, &monitor_sdata->work);
+                }
+        }
+
         if (prev_dev) {
                 skb->dev = prev_dev;
                 netif_receive_skb(skb);