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>

6 files changed, 33 insertions, 29 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 7d591816ed1..c484a882140 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -42,15 +42,6 @@ static bool nl80211_params_check(enum nl80211_iftype type,
 	if (!nl80211_type_check(type))
 		return false;
 
-	if (params->use_4addr > 0) {
-		switch(type) {
-		case NL80211_IFTYPE_AP_VLAN:
-		case NL80211_IFTYPE_STATION:
-			break;
-		default:
-			return false;
-		}
-	}
 	return true;
 }
 
@@ -107,12 +98,16 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
 					    params->mesh_id_len,
 					    params->mesh_id);
 
-	if (params->use_4addr >= 0)
-		sdata->use_4addr = !!params->use_4addr;
-
 	if (sdata->vif.type != NL80211_IFTYPE_MONITOR || !flags)
 		return 0;
 
+	if (type == NL80211_IFTYPE_AP_VLAN &&
+	    params && params->use_4addr == 0)
+		rcu_assign_pointer(sdata->u.vlan.sta, NULL);
+	else if (type == NL80211_IFTYPE_STATION &&
+		 params && params->use_4addr >= 0)
+		sdata->u.mgd.use_4addr = params->use_4addr;
+
 	sdata->u.mntr_flags = *flags;
 	return 0;
 }
@@ -827,7 +822,7 @@ static int ieee80211_change_station(struct wiphy *wiphy,
 			return -EINVAL;
 		}
 
-		if (vlansdata->use_4addr) {
+		if (params->vlan->ieee80211_ptr->use_4addr) {
 			if (vlansdata->u.vlan.sta)
 				return -EBUSY;
 
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 87d27f450a0..f13d76c9b57 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -312,6 +312,8 @@ struct ieee80211_if_managed {
 	} mfp; /* management frame protection */
 
 	int wmm_last_param_set;
+
+	u8 use_4addr;
 };
 
 enum ieee80211_ibss_request {
@@ -459,8 +461,6 @@ struct ieee80211_sub_if_data {
 	int force_unicast_rateidx; /* forced TX rateidx for unicast frames */
 	int max_ratectrl_rateidx; /* max TX rateidx for rate control */
 
-	bool use_4addr; /* use 4-address frames */
-
 	union {
 		struct ieee80211_if_ap ap;
 		struct ieee80211_if_wds wds;
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 1f02b0610e8..1bf12a26b45 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -752,7 +752,8 @@ int ieee80211_if_change_type(struct ieee80211_sub_if_data *sdata,
 		ieee80211_mandatory_rates(sdata->local,
 			sdata->local->hw.conf.channel->band);
 	sdata->drop_unencrypted = 0;
-	sdata->use_4addr = 0;
+	if (type == NL80211_IFTYPE_STATION)
+		sdata->u.mgd.use_4addr = false;
 
 	return 0;
 }
@@ -810,6 +811,12 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
 	/* setup type-dependent data */
 	ieee80211_setup_sdata(sdata, type);
 
+	if (params) {
+		ndev->ieee80211_ptr->use_4addr = params->use_4addr;
+		if (type == NL80211_IFTYPE_STATION)
+			sdata->u.mgd.use_4addr = params->use_4addr;
+	}
+
 	ret = register_netdevice(ndev);
 	if (ret)
 		goto fail;
@@ -820,9 +827,6 @@ int ieee80211_if_add(struct ieee80211_local *local, const char *name,
 					    params->mesh_id_len,
 					    params->mesh_id);
 
-	if (params && params->use_4addr >= 0)
-		sdata->use_4addr = !!params->use_4addr;
-
 	mutex_lock(&local->iflist_mtx);
 	list_add_tail_rcu(&sdata->list, &local->interfaces);
 	mutex_unlock(&local->iflist_mtx);
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 8084b622e97..dd8ec8d5e8b 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -328,7 +328,9 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	if (!wiphy)
 		return NULL;
 
-	wiphy->flags |= WIPHY_FLAG_NETNS_OK;
+	wiphy->flags |= WIPHY_FLAG_NETNS_OK |
+			WIPHY_FLAG_4ADDR_AP |
+			WIPHY_FLAG_4ADDR_STATION;
 	wiphy->privid = mac80211_wiphy_privid;
 
 	/* Yes, putting cfg80211_bss into ieee80211_bss is a hack */
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 775365f856c..96f13ad05d3 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1192,10 +1192,13 @@ __ieee80211_data_to_8023(struct ieee80211_rx_data *rx)
 	struct net_device *dev = sdata->dev;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
 
-	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN && !sdata->use_4addr &&
-	    ieee80211_has_a4(hdr->frame_control))
+	if (ieee80211_has_a4(hdr->frame_control) &&
+	    sdata->vif.type == NL80211_IFTYPE_AP_VLAN && !sdata->u.vlan.sta)
 		return -1;
-	if (sdata->use_4addr && is_multicast_ether_addr(hdr->addr1))
+
+	if (is_multicast_ether_addr(hdr->addr1) &&
+	    ((sdata->vif.type == NL80211_IFTYPE_AP_VLAN && sdata->u.vlan.sta) ||
+	     (sdata->vif.type == NL80211_IFTYPE_STATION && sdata->u.mgd.use_4addr)))
 		return -1;
 
 	return ieee80211_data_to_8023(rx->skb, dev->dev_addr, sdata->vif.type);
@@ -1245,7 +1248,8 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
 	if ((sdata->vif.type == NL80211_IFTYPE_AP ||
 	     sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
 	    !(sdata->flags & IEEE80211_SDATA_DONT_BRIDGE_PACKETS) &&
-	    (rx->flags & IEEE80211_RX_RA_MATCH) && !rx->sdata->use_4addr) {
+	    (rx->flags & IEEE80211_RX_RA_MATCH) &&
+	    (sdata->vif.type != NL80211_IFTYPE_AP_VLAN || !sdata->u.vlan.sta)) {
 		if (is_multicast_ether_addr(ehdr->h_dest)) {
 			/*
 			 * send multicast frames both to higher layers in
@@ -2007,7 +2011,7 @@ static int prepare_for_handlers(struct ieee80211_sub_if_data *sdata,
 
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_STATION:
-		if (!bssid && !sdata->use_4addr)
+		if (!bssid && !sdata->u.mgd.use_4addr)
 			return 0;
 		if (!multicast &&
 		    compare_ether_addr(sdata->dev->dev_addr, hdr->addr1) != 0) {
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index b3c1faeb592..5af2f40ea4d 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);