mac80211: keep sending peer candidate events while in listen state

Instead of sending peer candidate events just once, send them as long
as the peer remains in the LISTEN state in the peering state machine,
when userspace is implementing the peering manager.
Userspace may silence the events from a peer by progressing the state
machine or by setting the link state to BLOCKED.

Fixes the problem that a mesh peering process won't be fired again after
the previous first peering trial fails due to like air propagation error
if the peering is managed by user space such as wpa_supplicant.

This patch works with another patch for wpa_supplicant described here
which fires a peering process again triggered by the notice from kernel.
http://lists.shmoo.com/pipermail/hostap/2014-November/031235.html

Signed-off-by: Kenzoh Nishikawa <Kenzoh.Nishikawa@jp.sony.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mesh_plink.c

@@ -523,6 +523,13 @@ void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata,
 	    sdata->u.mesh.mshcfg.auto_open_plinks &&
 	    rssi_threshold_check(sdata, sta))
 		changed = mesh_plink_open(sta);
+	else if (sta->plink_state == NL80211_PLINK_LISTEN &&
+		 (sdata->u.mesh.user_mpm ||
+		  sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED))
+		cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
+						   elems->ie_start,
+						   elems->total_len,
+						   GFP_ATOMIC);
 
 	ieee80211_mps_frame_release(sta, elems);
 out: