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>

1 files changed, 19 insertions, 0 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index ab369e2a5282..741fb8bbc4a0 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -317,6 +317,7 @@ enum ieee80211_sta_flags {
         IEEE80211_STA_MFP_ENABLED       = BIT(6),
         IEEE80211_STA_UAPSD_ENABLED     = BIT(7),
         IEEE80211_STA_NULLFUNC_ACKED    = BIT(8),
+        IEEE80211_STA_RESET_SIGNAL_AVE  = BIT(9),
 };
 
 struct ieee80211_if_managed {
@@ -359,6 +360,24 @@ struct ieee80211_if_managed {
         int wmm_last_param_set;
 
         u8 use_4addr;
+
+        /* Signal strength from the last Beacon frame in the current BSS. */
+        int last_beacon_signal;
+
+        /*
+         * Weighted average of the signal strength from Beacon frames in the
+         * current BSS. This is in units of 1/16 of the signal unit to maintain
+         * accuracy and to speed up calculations, i.e., the value need to be
+         * divided by 16 to get the actual value.
+         */
+        int ave_beacon_signal;
+
+        /*
+         * Last Beacon frame signal strength average (ave_beacon_signal / 16)
+         * that triggered a cqm event. 0 indicates that no event has been
+         * generated for the current association.
+         */
+        int last_cqm_event_signal;
 };
 
 enum ieee80211_ibss_request {