CHROMIUMOS: mac80211: send last 3/5 probe requests as unicast

chromeos/compat-wireless/net/mac80211/mlme.c

 /*
  * BSS client mode implementation
  * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
  * Copyright 2004, Instant802 Networks, Inc.
  * Copyright 2005, Devicescape Software, Inc.
  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ skipping 1009 matching lines @@
                 return;
 
         mod_timer(&sdata->u.mgd.conn_mon_timer,
                   round_jiffies_up(jiffies + IEEE80211_CONNECTION_IDLE_TIME));
 }
 
 static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
 {
         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
         const u8 *ssid;
+        u8 *dst = ifmgd->associated->bssid;
+        u8 unicast_limit = max(1, IEEE80211_MAX_PROBE_TRIES - 3);
+
+        /*
+         * Try sending broadcast probe requests for the last three
+         * probe requests after the first ones failed since some
+         * buggy APs only support broadcast probe requests.
+         */
+        if (ifmgd->probe_send_count >= unicast_limit)
+                dst = NULL;
 
         ssid = ieee80211_bss_get_ie(ifmgd->associated, WLAN_EID_SSID);
-        ieee80211_send_probe_req(sdata, ifmgd->associated->bssid,
-                                 ssid + 2, ssid[1], NULL, 0);
+        ieee80211_send_probe_req(sdata, dst, ssid + 2, ssid[1], NULL, 0);
 
         ifmgd->probe_send_count++;
         ifmgd->probe_timeout = jiffies + IEEE80211_PROBE_WAIT;
         run_again(ifmgd, ifmgd->probe_timeout);
 }
 
 static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
                                    bool beacon)
 {
         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
@@ skipping 1335 matching lines @@
                                enum nl80211_cqm_rssi_threshold_event rssi_event,
                                gfp_t gfp)
 {
         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 
         trace_api_cqm_rssi_notify(sdata, rssi_event);
 
         cfg80211_cqm_rssi_notify(sdata->dev, rssi_event, gfp);
 }
 EXPORT_SYMBOL(ieee80211_cqm_rssi_notify);