cfg80211: introduce capability for 4addr mode

It's very likely that not many devices will support
four-address mode in station or AP mode so introduce
capability bits for both modes, set them in mac80211
and check them when userspace tries to use the mode.
Also, keep track of 4addr in cfg80211 (wireless_dev)
and not in mac80211 any more. mac80211 can also be
improved for the VLAN case by not looking at the
4addr flag but maintaining the station pointer for
it correctly. However, keep track of use_4addr for
station mode in mac80211 to avoid all the derefs.

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

1 files changed, 3 insertions, 4 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index b3c1faeb5927..5af2f40ea4db 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1051,7 +1051,7 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
 
         hdr = (struct ieee80211_hdr *) skb->data;
 
-        if ((sdata->vif.type == NL80211_IFTYPE_AP_VLAN) && sdata->use_4addr)
+        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
                 tx->sta = rcu_dereference(sdata->u.vlan.sta);
         if (!tx->sta)
                 tx->sta = sta_info_get(local, hdr->addr1);
@@ -1632,8 +1632,7 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
         switch (sdata->vif.type) {
         case NL80211_IFTYPE_AP_VLAN:
                 rcu_read_lock();
-                if (sdata->use_4addr)
-                        sta = rcu_dereference(sdata->u.vlan.sta);
+                sta = rcu_dereference(sdata->u.vlan.sta);
                 if (sta) {
                         fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
                         /* RA TA DA SA */
@@ -1727,7 +1726,7 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
 #endif
         case NL80211_IFTYPE_STATION:
                 memcpy(hdr.addr1, sdata->u.mgd.bssid, ETH_ALEN);
-                if (sdata->use_4addr && ethertype != ETH_P_PAE) {
+                if (sdata->u.mgd.use_4addr && ethertype != ETH_P_PAE) {
                         fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
                         /* RA TA DA SA */
                         memcpy(hdr.addr2, dev->dev_addr, ETH_ALEN);