[MAC80211]: implement ERP info change notifications

zd1211rw and bcm43xx are interested in being notified when ERP IE conditions
change, so that they can reprogram a register which affects how control frames
are transmitted.

This patch adds an interface similar to the one that can be found in softmac.
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Jiri Benc <jbenc@suse.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/mac80211.h

@@ -697,6 +697,14 @@ struct ieee80211_ops {
 	void (*sta_table_notification)(struct ieee80211_hw *hw,
 				       int num_sta);
 
+	/* Handle ERP IE change notifications. Must be atomic. */
+	void (*erp_ie_changed)(struct ieee80211_hw *hw, u8 changes,
+			       int cts_protection, int preamble);
+
+	/* Flags for the erp_ie_changed changes parameter */
+#define IEEE80211_ERP_CHANGE_PROTECTION (1<<0) /* protection flag changed */
+#define IEEE80211_ERP_CHANGE_PREAMBLE (1<<1) /* barker preamble mode changed */
+
 	/* Configure TX queue parameters (EDCF (aifs, cw_min, cw_max),
 	 * bursting) for a hardware TX queue.
 	 * queue = IEEE80211_TX_QUEUE_*.

net/mac80211/ieee80211.c

@@ -464,8 +464,10 @@ static int ieee80211_open(struct net_device *dev)
 	if (sdata->type == IEEE80211_IF_TYPE_MNTR) {
 		local->monitors++;
 		local->hw.conf.flags |= IEEE80211_CONF_RADIOTAP;
-	} else
+	} else {
 		ieee80211_if_config(dev);
+		ieee80211_reset_erp_info(dev);
+	}
 
 	if (sdata->type == IEEE80211_IF_TYPE_STA &&
 	    !local->user_space_mlme)
@@ -748,6 +750,27 @@ int ieee80211_hw_config(struct ieee80211_local *local)
 	return ret;
 }
 
+void ieee80211_erp_info_change_notify(struct net_device *dev, u8 changes)
+{
+	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	if (local->ops->erp_ie_changed)
+		local->ops->erp_ie_changed(local_to_hw(local), changes,
+					   sdata->use_protection,
+					   !sdata->short_preamble);
+}
+
+void ieee80211_reset_erp_info(struct net_device *dev)
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+	sdata->short_preamble = 0;
+	sdata->use_protection = 0;
+	ieee80211_erp_info_change_notify(dev,
+					 IEEE80211_ERP_CHANGE_PROTECTION |
+					 IEEE80211_ERP_CHANGE_PREAMBLE);
+}
+
 struct dev_mc_list *ieee80211_get_mc_list_item(struct ieee80211_hw *hw,
 					       struct dev_mc_list *prev,
 					       void **ptr)

net/mac80211/ieee80211_i.h

@@ -788,6 +788,8 @@ struct sta_info * ieee80211_ibss_add_sta(struct net_device *dev,
 					 u8 *addr);
 int ieee80211_sta_deauthenticate(struct net_device *dev, u16 reason);
 int ieee80211_sta_disassociate(struct net_device *dev, u16 reason);
+void ieee80211_erp_info_change_notify(struct net_device *dev, u8 changes);
+void ieee80211_reset_erp_info(struct net_device *dev);
 
 /* ieee80211_iface.c */
 int ieee80211_if_add(struct net_device *dev, const char *name,

net/mac80211/ieee80211_ioctl.c

@@ -1054,17 +1054,21 @@ static int ieee80211_ioctl_prism2_param(struct net_device *dev,
 		break;
 
 	case PRISM2_PARAM_CTS_PROTECT_ERP_FRAMES:
-		if (sdata->type != IEEE80211_IF_TYPE_AP)
+		if (sdata->type == IEEE80211_IF_TYPE_AP) {
+			sdata->use_protection = !!value;
+			ieee80211_erp_info_change_notify(dev, IEEE80211_ERP_CHANGE_PROTECTION);
+		} else {
 			ret = -ENOENT;
-		else
-			sdata->use_protection = value;
+		}
 		break;
 
 	case PRISM2_PARAM_PREAMBLE:
-		if (sdata->type != IEEE80211_IF_TYPE_AP)
+		if (sdata->type != IEEE80211_IF_TYPE_AP) {
+			sdata->short_preamble = !!value;
+			ieee80211_erp_info_change_notify(dev, IEEE80211_ERP_CHANGE_PREAMBLE);
+		} else {
 			ret = -ENOENT;
-		else
-			sdata->short_preamble = value;
+		}
 		break;
 
 	case PRISM2_PARAM_STAT_TIME:

net/mac80211/ieee80211_sta.c

@@ -319,6 +319,7 @@ static void ieee80211_handle_erp_ie(struct net_device *dev, u8 erp_value)
 	struct ieee80211_if_sta *ifsta = &sdata->u.sta;
 	int use_protection = (erp_value & WLAN_ERP_USE_PROTECTION) != 0;
 	int preamble_mode = (erp_value & WLAN_ERP_BARKER_PREAMBLE) != 0;
+	u8 changes = 0;
 
 	if (use_protection != sdata->use_protection) {
 		if (net_ratelimit()) {
@@ -329,6 +330,7 @@ static void ieee80211_handle_erp_ie(struct net_device *dev, u8 erp_value)
 			       MAC_ARG(ifsta->bssid));
 		}
 		sdata->use_protection = use_protection;
+		changes |= IEEE80211_ERP_CHANGE_PROTECTION;
 	}
 
 	if (!preamble_mode != sdata->short_preamble) {
@@ -341,7 +343,11 @@ static void ieee80211_handle_erp_ie(struct net_device *dev, u8 erp_value)
 			       MAC_ARG(ifsta->bssid));
 		}
 		sdata->short_preamble = !preamble_mode;
+		changes |= IEEE80211_ERP_CHANGE_PREAMBLE;
 	}
+
+	if (changes)
+		ieee80211_erp_info_change_notify(dev, changes);
 }
 
 
@@ -400,7 +406,6 @@ static void ieee80211_set_associated(struct net_device *dev,
 				     struct ieee80211_if_sta *ifsta, int assoc)
 {
 	union iwreq_data wrqu;
-	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
 	if (ifsta->associated == assoc)
 		return;
@@ -428,8 +433,7 @@ static void ieee80211_set_associated(struct net_device *dev,
 		ieee80211_sta_send_associnfo(dev, ifsta);
 	} else {
 		netif_carrier_off(dev);
-		sdata->short_preamble = 0;
-		sdata->use_protection = 0;
+		ieee80211_reset_erp_info(dev);
 		memset(wrqu.ap_addr.sa_data, 0, ETH_ALEN);
 	}
 	wrqu.ap_addr.sa_family = ARPHRD_ETHER;