cfg80211: Add nl80211 event for deletion of a station entry

Indicate an NL80211_CMD_DEL_STATION event when a station entry in
mac80211 is deleted to match with the NL80211_CMD_NEW_STATION event
that is used when the entry was added. This is needed, e.g., to allow
user space to remove a peer from RSN IBSS Authenticator state machine
to avoid re-authentication and re-keying delays when the peer is not
reachable anymore.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/cfg80211.h

@@ -2666,6 +2666,15 @@ void cfg80211_remain_on_channel_expired(struct net_device *dev,
 void cfg80211_new_sta(struct net_device *dev, const u8 *mac_addr,
 		      struct station_info *sinfo, gfp_t gfp);
 
+/**
+ * cfg80211_del_sta - notify userspace about deletion of a station
+ *
+ * @dev: the netdev
+ * @mac_addr: the station's address
+ * @gfp: allocation flags
+ */
+void cfg80211_del_sta(struct net_device *dev, const u8 *mac_addr, gfp_t gfp);
+
 /**
  * cfg80211_rx_mgmt - notification of received, unprocessed management frame
  * @dev: network device

net/mac80211/sta_info.c

@@ -698,6 +698,8 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
 #endif /* CONFIG_MAC80211_VERBOSE_DEBUG */
 	cancel_work_sync(&sta->drv_unblock_wk);
 
+	cfg80211_del_sta(sdata->dev, sta->sta.addr, GFP_KERNEL);
+
 	rate_control_remove_sta_debugfs(sta);
 	ieee80211_sta_debugfs_remove(sta);
 

net/wireless/mlme.c

@@ -770,6 +770,15 @@ void cfg80211_new_sta(struct net_device *dev, const u8 *mac_addr,
 }
 EXPORT_SYMBOL(cfg80211_new_sta);
 
+void cfg80211_del_sta(struct net_device *dev, const u8 *mac_addr, gfp_t gfp)
+{
+	struct wiphy *wiphy = dev->ieee80211_ptr->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+
+	nl80211_send_sta_del_event(rdev, dev, mac_addr, gfp);
+}
+EXPORT_SYMBOL(cfg80211_del_sta);
+
 struct cfg80211_mgmt_registration {
 	struct list_head list;
 

net/wireless/nl80211.c

@@ -5966,6 +5966,40 @@ void nl80211_send_sta_event(struct cfg80211_registered_device *rdev,
 				nl80211_mlme_mcgrp.id, gfp);
 }
 
+void nl80211_send_sta_del_event(struct cfg80211_registered_device *rdev,
+				struct net_device *dev, const u8 *mac_addr,
+				gfp_t gfp)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_GOODSIZE, gfp);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_DEL_STATION);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, dev->ifindex);
+	NLA_PUT(msg, NL80211_ATTR_MAC, ETH_ALEN, mac_addr);
+
+	if (genlmsg_end(msg, hdr) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+				nl80211_mlme_mcgrp.id, gfp);
+	return;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	nlmsg_free(msg);
+}
+
 int nl80211_send_mgmt(struct cfg80211_registered_device *rdev,
 		      struct net_device *netdev, u32 nlpid,
 		      int freq, const u8 *buf, size_t len, gfp_t gfp)

net/wireless/nl80211.h

@@ -79,6 +79,9 @@ void nl80211_send_remain_on_channel_cancel(
 void nl80211_send_sta_event(struct cfg80211_registered_device *rdev,
 			    struct net_device *dev, const u8 *mac_addr,
 			    struct station_info *sinfo, gfp_t gfp);
+void nl80211_send_sta_del_event(struct cfg80211_registered_device *rdev,
+				struct net_device *dev, const u8 *mac_addr,
+				gfp_t gfp);
 
 int nl80211_send_mgmt(struct cfg80211_registered_device *rdev,
 		      struct net_device *netdev, u32 nlpid, int freq,