mac80211: Track Beacon signal strength and implement cqm events
Calculate a running average of the signal strength reported for Beacon
frames and indicate cqm events if the average value moves below or
above the configured threshold value (and filter out repetitive events
with by using the configured hysteresis).
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index c686d1b..de7519e 100644
--- 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 @@
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 @@
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 @@
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()) {