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>

5 files changed, 51 insertions, 3 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index f2c8cd22d317..5d4afead804e 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -73,8 +73,29 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
                 sdata->u.mgd.use_4addr = params->use_4addr;
         }
 
-        if (sdata->vif.type == NL80211_IFTYPE_MONITOR && flags) {
+        if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
                 struct ieee80211_local *local = sdata->local;
+                struct ieee80211_sub_if_data *monitor_sdata;
+                u32 mu_mntr_cap_flag = NL80211_EXT_FEATURE_MU_MIMO_AIR_SNIFFER;
+
+                monitor_sdata = rtnl_dereference(local->monitor_sdata);
+                if (monitor_sdata &&
+                    wiphy_ext_feature_isset(wiphy, mu_mntr_cap_flag)) {
+                        memcpy(monitor_sdata->vif.bss_conf.mu_group.membership,
+                               params->vht_mumimo_groups, WLAN_MEMBERSHIP_LEN);
+                        memcpy(monitor_sdata->vif.bss_conf.mu_group.position,
+                               params->vht_mumimo_groups + WLAN_MEMBERSHIP_LEN,
+                               WLAN_USER_POSITION_LEN);
+                        monitor_sdata->vif.mu_mimo_owner = true;
+                        ieee80211_bss_info_change_notify(monitor_sdata,
+                                                         BSS_CHANGED_MU_GROUPS);
+
+                        ether_addr_copy(monitor_sdata->u.mntr.mu_follow_addr,
+                                        params->macaddr);
+                }
+
+                if (!flags)
+                        return 0;
 
                 if (ieee80211_sdata_running(sdata)) {
                         u32 mask = MONITOR_FLAG_COOK_FRAMES |
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 42a41ae405ba..c39f93b48791 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -162,7 +162,8 @@ static inline void drv_bss_info_changed(struct ieee80211_local *local,
                 return;
 
         if (WARN_ON_ONCE(sdata->vif.type == NL80211_IFTYPE_P2P_DEVICE ||
-                         sdata->vif.type == NL80211_IFTYPE_MONITOR))
+                         (sdata->vif.type == NL80211_IFTYPE_MONITOR &&
+                          !sdata->vif.mu_mimo_owner)))
                 return;
 
         if (!check_sdata_in_driver(sdata))
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9211cce10d3e..75761686a98b 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -3,7 +3,7 @@
  * Copyright 2005, Devicescape Software, Inc.
  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
  * Copyright 2007-2010  Johannes Berg <johannes@sipsolutions.net>
- * Copyright 2013-2014  Intel Mobile Communications GmbH
+ * Copyright 2013-2015  Intel Mobile Communications GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -826,6 +826,7 @@ struct txq_info {
 
 struct ieee80211_if_mntr {
         u32 flags;
+        u8 mu_follow_addr[ETH_ALEN] __aligned(2);
 };
 
 struct ieee80211_sub_if_data {
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index c8509d95e09d..b0abddc714ef 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -43,6 +43,8 @@
  * by either the RTNL, the iflist_mtx or RCU.
  */
 
+static void ieee80211_iface_work(struct work_struct *work);
+
 bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata)
 {
         struct ieee80211_chanctx_conf *chanctx_conf;
@@ -448,6 +450,9 @@ int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
                 return ret;
         }
 
+        skb_queue_head_init(&sdata->skb_queue);
+        INIT_WORK(&sdata->work, ieee80211_iface_work);
+
         return 0;
 }
 
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);