mac80211: speed up AP probing using nullfunc frames

If the nullfunc frame used to probe the AP was not acked, there is no point
in waiting for the probe timeout, so advance to the next try (or disconnect)
immediately.
If we do reach the probe timeout without having received a tx status, the
connection is probably really bad and worth disconnecting.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 68 insertions, 25 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index f570801514f1..3a1dde3c7956 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1065,16 +1065,20 @@ static void ieee80211_reset_ap_probe(struct ieee80211_sub_if_data *sdata)
 }
 
 void ieee80211_sta_tx_notify(struct ieee80211_sub_if_data *sdata,
-                             struct ieee80211_hdr *hdr)
+                             struct ieee80211_hdr *hdr, bool ack)
 {
         if (!ieee80211_is_data(hdr->frame_control))
             return;
 
-        ieee80211_sta_reset_conn_monitor(sdata);
+        if (ack)
+                ieee80211_sta_reset_conn_monitor(sdata);
 
         if (ieee80211_is_nullfunc(hdr->frame_control) &&
             sdata->u.mgd.probe_send_count > 0) {
-                sdata->u.mgd.probe_send_count = 0;
+                if (ack)
+                        sdata->u.mgd.probe_send_count = 0;
+                else
+                        sdata->u.mgd.nullfunc_failed = true;
                 ieee80211_queue_work(&sdata->local->hw, &sdata->work);
         }
 }
@@ -1101,9 +1105,10 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata)
          * anymore. The timeout will be reset if the frame is ACKed by
          * the AP.
          */
-        if (sdata->local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS)
+        if (sdata->local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
+                ifmgd->nullfunc_failed = false;
                 ieee80211_send_nullfunc(sdata->local, sdata, 0);
-        else {
+        } else {
                 ssid = ieee80211_bss_get_ie(ifmgd->associated, WLAN_EID_SSID);
                 ieee80211_send_probe_req(sdata, dst, ssid + 2, ssid[1], NULL, 0);
         }
@@ -1912,6 +1917,31 @@ static void ieee80211_sta_timer(unsigned long data)
         ieee80211_queue_work(&local->hw, &sdata->work);
 }
 
+static void ieee80211_sta_connection_lost(struct ieee80211_sub_if_data *sdata,
+                                          u8 *bssid)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+
+        ifmgd->flags &= ~(IEEE80211_STA_CONNECTION_POLL |
+                          IEEE80211_STA_BEACON_POLL);
+
+        ieee80211_set_disassoc(sdata, true, true);
+        mutex_unlock(&ifmgd->mtx);
+        mutex_lock(&local->mtx);
+        ieee80211_recalc_idle(local);
+        mutex_unlock(&local->mtx);
+        /*
+         * must be outside lock due to cfg80211,
+         * but that's not a problem.
+         */
+        ieee80211_send_deauth_disassoc(sdata, bssid,
+                        IEEE80211_STYPE_DEAUTH,
+                        WLAN_REASON_DISASSOC_DUE_TO_INACTIVITY,
+                        NULL, true);
+        mutex_lock(&ifmgd->mtx);
+}
+
 void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
 {
         struct ieee80211_local *local = sdata->local;
@@ -1936,11 +1966,38 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
                 /* ACK received for nullfunc probing frame */
                 if (!ifmgd->probe_send_count)
                         ieee80211_reset_ap_probe(sdata);
-
-                else if (time_is_after_jiffies(ifmgd->probe_timeout))
+                else if (ifmgd->nullfunc_failed) {
+                        if (ifmgd->probe_send_count < max_tries) {
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+                                wiphy_debug(local->hw.wiphy,
+                                            "%s: No ack for nullfunc frame to"
+                                            " AP %pM, try %d\n",
+                                            sdata->name, bssid,
+                                            ifmgd->probe_send_count);
+#endif
+                                ieee80211_mgd_probe_ap_send(sdata);
+                        } else {
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+                                wiphy_debug(local->hw.wiphy,
+                                            "%s: No ack for nullfunc frame to"
+                                            " AP %pM, disconnecting.\n",
+                                            sdata->name, bssid,
+                                            ifmgd->probe_send_count);
+#endif
+                                ieee80211_sta_connection_lost(sdata, bssid);
+                        }
+                } else if (time_is_after_jiffies(ifmgd->probe_timeout))
                         run_again(ifmgd, ifmgd->probe_timeout);
-
-                else if (ifmgd->probe_send_count < max_tries) {
+                else if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+                        wiphy_debug(local->hw.wiphy,
+                                    "%s: Failed to send nullfunc to AP %pM"
+                                    " after %dms, disconnecting.\n",
+                                    sdata->name,
+                                    bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ);
+#endif
+                        ieee80211_sta_connection_lost(sdata, bssid);
+                } else if (ifmgd->probe_send_count < max_tries) {
 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
                         wiphy_debug(local->hw.wiphy,
                                     "%s: No probe response from AP %pM"
@@ -1955,27 +2012,13 @@ void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata)
                          * We actually lost the connection ... or did we?
                          * Let's make sure!
                          */
-                        ifmgd->flags &= ~(IEEE80211_STA_CONNECTION_POLL |
-                                          IEEE80211_STA_BEACON_POLL);
                         wiphy_debug(local->hw.wiphy,
                                     "%s: No probe response from AP %pM"
                                     " after %dms, disconnecting.\n",
                                     sdata->name,
                                     bssid, (1000 * IEEE80211_PROBE_WAIT)/HZ);
-                        ieee80211_set_disassoc(sdata, true, true);
-                        mutex_unlock(&ifmgd->mtx);
-                        mutex_lock(&local->mtx);
-                        ieee80211_recalc_idle(local);
-                        mutex_unlock(&local->mtx);
-                        /*
-                         * must be outside lock due to cfg80211,
-                         * but that's not a problem.
-                         */
-                        ieee80211_send_deauth_disassoc(sdata, bssid,
-                                        IEEE80211_STYPE_DEAUTH,
-                                        WLAN_REASON_DISASSOC_DUE_TO_INACTIVITY,
-                                        NULL, true);
-                        mutex_lock(&ifmgd->mtx);
+
+                        ieee80211_sta_connection_lost(sdata, bssid);
                 }
         }