mac80211: use nullfunc frames for 4-addr sta detection

@@ -312,6 +312,38 @@ void ieee80211_send_nullfunc(struct ieee
 	ieee80211_tx_skb(sdata, skb);
 }
 
+static void ieee80211_send_4addr_nullfunc(struct ieee80211_local *local,
+					  struct ieee80211_sub_if_data *sdata)
+{
+	struct sk_buff *skb;
+	struct ieee80211_hdr *nullfunc;
+	__le16 fc;
+
+	if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
+		return;
+
+	skb = dev_alloc_skb(local->hw.extra_tx_headroom + 30);
+	if (!skb) {
+		printk(KERN_DEBUG "%s: failed to allocate buffer for 4addr "
+		       "nullfunc frame\n", sdata->name);
+		return;
+	}
+	skb_reserve(skb, local->hw.extra_tx_headroom);
+
+	nullfunc = (struct ieee80211_hdr *) skb_put(skb, 30);
+	memset(nullfunc, 0, 30);
+	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
+			 IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
+	nullfunc->frame_control = fc;
+	memcpy(nullfunc->addr1, sdata->u.mgd.bssid, ETH_ALEN);
+	memcpy(nullfunc->addr2, sdata->vif.addr, ETH_ALEN);
+	memcpy(nullfunc->addr3, sdata->u.mgd.bssid, ETH_ALEN);
+	memcpy(nullfunc->addr4, sdata->vif.addr, ETH_ALEN);
+
+	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
+	ieee80211_tx_skb(sdata, skb);
+}
+
 /* spectrum management related things */
 static void ieee80211_chswitch_work(struct work_struct *work)
 {

@@ -1120,6 +1152,13 @@ static bool ieee80211_assoc_success(stru
 	ieee80211_set_associated(sdata, cbss, changed);
 
 	/*
+	 * If we're using 4-addr mode, let the AP know that we're
+	 * doing so, so that it can create the STA VLAN on its side
+	 */
+	if (ifmgd->use_4addr)
+		ieee80211_send_4addr_nullfunc(local, sdata);
+
+	/*
 	 * Start timer to probe the connection to the AP now.
 	 * Also start the timer that will detect beacon loss.
 	 */

@@ -1111,6 +1111,18 @@ ieee80211_rx_h_sta_process(struct ieee80
 	if (ieee80211_is_nullfunc(hdr->frame_control) ||
 	    ieee80211_is_qos_nullfunc(hdr->frame_control)) {
 		I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
+
+		/*
+		 * If we receive a 4-addr nullfunc frame from a STA
+		 * that was not moved to a 4-addr STA vlan yet, drop
+		 * the frame to the monitor interface, to make sure
+		 * that hostapd sees it
+		 */
+		if (ieee80211_has_a4(hdr->frame_control) &&
+		    (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
+		     (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
+		      !rx->sdata->u.vlan.sta)))
+			return RX_DROP_MONITOR;
 		/*
 		 * Update counter and free packet here to avoid
 		 * counting this as a dropped packed.

@@ -119,6 +119,27 @@ struct sta_info *sta_info_get(struct iee
 	return sta;
 }
 
+/*
+ * Get sta info either from the specified interface
+ * or from one of its vlans
+ */
+struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
+				  const u8 *addr)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct sta_info *sta;
+
+	sta = rcu_dereference(local->sta_hash[STA_HASH(addr)]);
+	while (sta) {
+		if ((sta->sdata == sdata ||
+		     sta->sdata->bss == sdata->bss) &&
+		    memcmp(sta->sta.addr, addr, ETH_ALEN) == 0)
+			break;
+		sta = rcu_dereference(sta->hnext);
+	}
+	return sta;
+}
+
 struct sta_info *sta_info_get_by_idx(struct ieee80211_sub_if_data *sdata,
 				     int idx)
 {

@@ -408,6 +408,9 @@ static inline u32 get_sta_flags(struct s
 struct sta_info *sta_info_get(struct ieee80211_sub_if_data *sdata,
 			      const u8 *addr);
 
+struct sta_info *sta_info_get_bss(struct ieee80211_sub_if_data *sdata,
+				  const u8 *addr);
+
 static inline
 void for_each_sta_info_type_check(struct ieee80211_local *local,
 				  const u8 *addr,

@@ -148,7 +148,7 @@ static int ieee80211_add_key(struct wiph
 	rcu_read_lock();
 
 	if (mac_addr) {
-		sta = sta_info_get(sdata, mac_addr);
+		sta = sta_info_get_bss(sdata, mac_addr);
 		if (!sta) {
 			ieee80211_key_free(key);
 			err = -ENOENT;

@@ -179,7 +179,7 @@ static int ieee80211_del_key(struct wiph
 	if (mac_addr) {
 		ret = -ENOENT;
 
-		sta = sta_info_get(sdata, mac_addr);
+		sta = sta_info_get_bss(sdata, mac_addr);
 		if (!sta)
 			goto out_unlock;
 

@@ -226,7 +226,7 @@ static int ieee80211_get_key(struct wiph
 	rcu_read_lock();
 
 	if (mac_addr) {
-		sta = sta_info_get(sdata, mac_addr);
+		sta = sta_info_get_bss(sdata, mac_addr);
 		if (!sta)
 			goto out;
 

@@ -419,7 +419,7 @@ static int ieee80211_get_station(struct 
 
 	rcu_read_lock();
 
-	sta = sta_info_get(sdata, mac);
+	sta = sta_info_get_bss(sdata, mac);
 	if (sta) {
 		ret = 0;
 		sta_set_sinfo(sta, sinfo);

@@ -775,7 +775,7 @@ static int ieee80211_del_station(struct 
 	if (mac) {
 		rcu_read_lock();
 
-		sta = sta_info_get(sdata, mac);
+		sta = sta_info_get_bss(sdata, mac);
 		if (!sta) {
 			rcu_read_unlock();
 			return -ENOENT;

@@ -803,7 +803,7 @@ static int ieee80211_change_station(stru
 
 	rcu_read_lock();
 
-	sta = sta_info_get(sdata, mac);
+	sta = sta_info_get_bss(sdata, mac);
 	if (!sta) {
 		rcu_read_unlock();
 		return -ENOENT;

@@ -1051,8 +1051,11 @@ ieee80211_tx_prepare(struct ieee80211_su
 
 	hdr = (struct ieee80211_hdr *) skb->data;
 
-	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
 		tx->sta = rcu_dereference(sdata->u.vlan.sta);
+		if (!tx->sta && sdata->dev->ieee80211_ptr->use_4addr)
+			return TX_DROP;
+	}
 	if (!tx->sta)
 		tx->sta = sta_info_get(sdata, hdr->addr1);