mac80211: Retry probe request few times

Retry 5 times  (chosen arbitary ), before assuming
that station is out of range.

Fixes frequent disassociations while connected to weak,
and sometimes even strong access points.

Signed-off-by: Maxim Levitky <maximlevitsky@gmail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ieee80211_i.h

@@ -280,6 +280,7 @@ struct ieee80211_if_managed {
 	struct work_struct beacon_loss_work;
 
 	unsigned long probe_timeout;
+	int probe_send_count;
 
 	struct mutex mtx;
 	struct ieee80211_bss *associated;

net/mac80211/mlme.c

@@ -31,6 +31,7 @@
 #define IEEE80211_AUTH_MAX_TRIES 3
 #define IEEE80211_ASSOC_TIMEOUT (HZ / 5)
 #define IEEE80211_ASSOC_MAX_TRIES 3
+#define IEEE80211_MAX_PROBE_TRIES 5
 
 /*
  * beacon loss detection timeout
@@ -1153,11 +1154,24 @@ void ieee80211_sta_rx_notify(struct ieee80211_sub_if_data *sdata,
 		  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;
+
+	ssid = ieee80211_bss_get_ie(&ifmgd->associated->cbss, WLAN_EID_SSID);
+	ieee80211_send_probe_req(sdata, ifmgd->associated->cbss.bssid,
+				 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;
-	const u8 *ssid;
 	bool already = false;
 
 	if (!netif_running(sdata->dev))
@@ -1200,18 +1214,12 @@ static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
 	if (already)
 		goto out;
 
-	ifmgd->probe_timeout = jiffies + IEEE80211_PROBE_WAIT;
-
 	mutex_lock(&sdata->local->iflist_mtx);
 	ieee80211_recalc_ps(sdata->local, -1);
 	mutex_unlock(&sdata->local->iflist_mtx);
 
-	ssid = ieee80211_bss_get_ie(&ifmgd->associated->cbss, WLAN_EID_SSID);
-	ieee80211_send_probe_req(sdata, ifmgd->associated->cbss.bssid,
-				 ssid + 2, ssid[1], NULL, 0);
-
-	run_again(ifmgd, ifmgd->probe_timeout);
-
+	ifmgd->probe_send_count = 0;
+	ieee80211_mgd_probe_ap_send(sdata);
  out:
 	mutex_unlock(&ifmgd->mtx);
 }
@@ -2064,17 +2072,27 @@ static void ieee80211_sta_work(struct work_struct *work)
 	if (ifmgd->flags & (IEEE80211_STA_BEACON_POLL |
 			    IEEE80211_STA_CONNECTION_POLL) &&
 	    ifmgd->associated) {
+		u8 bssid[ETH_ALEN];
+
+		memcpy(bssid, ifmgd->associated->cbss.bssid, ETH_ALEN);
 		if (time_is_after_jiffies(ifmgd->probe_timeout))
 			run_again(ifmgd, ifmgd->probe_timeout);
-		else {
-			u8 bssid[ETH_ALEN];
+
+		else if (ifmgd->probe_send_count < IEEE80211_MAX_PROBE_TRIES) {
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+			printk(KERN_DEBUG "No probe response from AP %pM"
+				" after %dms, try %d\n", bssid,
+				(1000 * IEEE80211_PROBE_WAIT)/HZ,
+				ifmgd->probe_send_count);
+#endif
+			ieee80211_mgd_probe_ap_send(sdata);
+		} else {
 			/*
 			 * We actually lost the connection ... or did we?
 			 * Let's make sure!
 			 */
 			ifmgd->flags &= ~(IEEE80211_STA_CONNECTION_POLL |
 					  IEEE80211_STA_BEACON_POLL);
-			memcpy(bssid, ifmgd->associated->cbss.bssid, ETH_ALEN);
 			printk(KERN_DEBUG "No probe response from AP %pM"
 				" after %dms, disconnecting.\n",
 				bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ);