mac80211: Track Beacon signal strength and implement cqm events

[safe/jmp/linux-2.6] / net / mac80211 / mlme.c

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index c686d1b..de7519e 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -46,6 +46,13 @@
  */
 #define IEEE80211_PROBE_WAIT           (HZ / 2)
 
+/*
+ * Weight given to the latest Beacon frame when calculating average signal
+ * strength for Beacon frames received in the current BSS. This must be
+ * between 1 and 15.
+ */
+#define IEEE80211_SIGNAL_AVE_WEIGHT    3
+
 #define TMR_RUNNING_TIMER      0
 #define TMR_RUNNING_CHANSW     1
 
@@ -732,6 +739,8 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
        sdata->u.mgd.associated = cbss;
        memcpy(sdata->u.mgd.bssid, cbss->bssid, ETH_ALEN);
 
+       sdata->u.mgd.flags |= IEEE80211_STA_RESET_SIGNAL_AVE;
+
        /* just to be sure */
        sdata->u.mgd.flags &= ~(IEEE80211_STA_CONNECTION_POLL |
                                IEEE80211_STA_BEACON_POLL);
@@ -1347,6 +1356,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
                                     struct ieee80211_rx_status *rx_status)
 {
        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
+       struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf;
        size_t baselen;
        struct ieee802_11_elems elems;
        struct ieee80211_local *local = sdata->local;
@@ -1382,6 +1392,41 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
        if (memcmp(bssid, mgmt->bssid, ETH_ALEN) != 0)
                return;
 
+       /* Track average RSSI from the Beacon frames of the current AP */
+       ifmgd->last_beacon_signal = rx_status->signal;
+       if (ifmgd->flags & IEEE80211_STA_RESET_SIGNAL_AVE) {
+               ifmgd->flags &= ~IEEE80211_STA_RESET_SIGNAL_AVE;
+               ifmgd->ave_beacon_signal = rx_status->signal;
+               ifmgd->last_cqm_event_signal = 0;
+       } else {
+               ifmgd->ave_beacon_signal =
+                       (IEEE80211_SIGNAL_AVE_WEIGHT * rx_status->signal * 16 +
+                        (16 - IEEE80211_SIGNAL_AVE_WEIGHT) *
+                        ifmgd->ave_beacon_signal) / 16;
+       }
+       if (bss_conf->cqm_rssi_thold &&
+           !(local->hw.flags & IEEE80211_HW_SUPPORTS_CQM_RSSI)) {
+               int sig = ifmgd->ave_beacon_signal / 16;
+               int last_event = ifmgd->last_cqm_event_signal;
+               int thold = bss_conf->cqm_rssi_thold;
+               int hyst = bss_conf->cqm_rssi_hyst;
+               if (sig < thold &&
+                   (last_event == 0 || sig < last_event - hyst)) {
+                       ifmgd->last_cqm_event_signal = sig;
+                       ieee80211_cqm_rssi_notify(
+                               &sdata->vif,
+                               NL80211_CQM_RSSI_THRESHOLD_EVENT_LOW,
+                               GFP_KERNEL);
+               } else if (sig > thold &&
+                          (last_event == 0 || sig > last_event + hyst)) {
+                       ifmgd->last_cqm_event_signal = sig;
+                       ieee80211_cqm_rssi_notify(
+                               &sdata->vif,
+                               NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH,
+                               GFP_KERNEL);
+               }
+       }
+
        if (ifmgd->flags & IEEE80211_STA_BEACON_POLL) {
 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
                if (net_ratelimit()) {