mac80211: Add support for connection quality monitoring

Add support for the set_cqm_config op. This op function configures the
requested connection quality monitor rssi threshold and rssi hysteresis
values to the hardware  if the hardware supports
IEEE80211_HW_SUPPORTS_CQM.

For unsupported hardware, currently -EOPNOTSUPP is returned, so the mac80211
is currently not doing connection quality monitoring on the host. This could be
added later, if needed.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 72 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d14226f29ff..1a8f50af49a 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -144,6 +144,7 @@ struct ieee80211_low_level_stats {
  *      new beacon (beaconing modes)
  * @BSS_CHANGED_BEACON_ENABLED: Beaconing should be
  *      enabled/disabled (beaconing modes)
+ * @BSS_CHANGED_CQM: Connection quality monitor config changed
  */
 enum ieee80211_bss_change {
         BSS_CHANGED_ASSOC               = 1<<0,
@@ -156,6 +157,7 @@ enum ieee80211_bss_change {
         BSS_CHANGED_BSSID               = 1<<7,
         BSS_CHANGED_BEACON              = 1<<8,
         BSS_CHANGED_BEACON_ENABLED      = 1<<9,
+        BSS_CHANGED_CQM                 = 1<<10,
 };
 
 /**
@@ -185,6 +187,9 @@ enum ieee80211_bss_change {
  * @enable_beacon: whether beaconing should be enabled or not
  * @ht_operation_mode: HT operation mode (like in &struct ieee80211_ht_info).
  *      This field is only valid when the channel type is one of the HT types.
+ * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
+ *      implies disabled
+ * @cqm_rssi_hyst: Connection quality monitor RSSI hysteresis
  */
 struct ieee80211_bss_conf {
         const u8 *bssid;
@@ -202,6 +207,8 @@ struct ieee80211_bss_conf {
         u64 timestamp;
         u32 basic_rates;
         u16 ht_operation_mode;
+        s32 cqm_rssi_thold;
+        u32 cqm_rssi_hyst;
 };
 
 /**
@@ -959,6 +966,12 @@ enum ieee80211_tkip_key_type {
  *      periodic keep-alives to the AP and probing the AP on beacon loss.
  *      When this flag is set, signaling beacon-loss will cause an immediate
  *      change to disassociated state.
+ *
+ * @IEEE80211_HW_SUPPORTS_CQM_RSSI:
+ *      Hardware can do connection quality monitoring - i.e. it can monitor
+ *      connection quality related parameters, such as the RSSI level and
+ *      provide notifications if configured trigger levels are reached.
+ *
  */
 enum ieee80211_hw_flags {
         IEEE80211_HW_HAS_RATE_CONTROL                   = 1<<0,
@@ -981,6 +994,7 @@ enum ieee80211_hw_flags {
         IEEE80211_HW_SUPPORTS_UAPSD                     = 1<<17,
         IEEE80211_HW_REPORTS_TX_ACK_STATUS              = 1<<18,
         IEEE80211_HW_CONNECTION_MONITOR                 = 1<<19,
+        IEEE80211_HW_SUPPORTS_CQM_RSSI                  = 1<<20,
 };
 
 /**
@@ -2390,6 +2404,22 @@ void ieee80211_beacon_loss(struct ieee80211_vif *vif);
  */
 void ieee80211_connection_loss(struct ieee80211_vif *vif);
 
+/**
+ * ieee80211_cqm_rssi_notify - inform a configured connection quality monitoring
+ *      rssi threshold triggered
+ *
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ * @rssi_event: the RSSI trigger event type
+ * @gfp: context flags
+ *
+ * When the %IEEE80211_HW_SUPPORTS_CQM_RSSI is set, and a connection quality
+ * monitoring is configured with an rssi threshold, the driver will inform
+ * whenever the rssi level reaches the threshold.
+ */
+void ieee80211_cqm_rssi_notify(struct ieee80211_vif *vif,
+                               enum nl80211_cqm_rssi_threshold_event rssi_event,
+                               gfp_t gfp);
+
 /* Rate control API */
 
 /**
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b7116ef84a3..c8f520529ee 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1402,6 +1402,32 @@ static int ieee80211_set_power_mgmt(struct wiphy *wiphy, struct net_device *dev,
         return 0;
 }
 
+static int ieee80211_set_cqm_rssi_config(struct wiphy *wiphy,
+                                         struct net_device *dev,
+                                         s32 rssi_thold, u32 rssi_hyst)
+{
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct ieee80211_vif *vif = &sdata->vif;
+        struct ieee80211_bss_conf *bss_conf = &vif->bss_conf;
+
+        if (!(local->hw.flags & IEEE80211_HW_SUPPORTS_CQM_RSSI))
+                return -EOPNOTSUPP;
+
+        if (rssi_thold == bss_conf->cqm_rssi_thold &&
+            rssi_hyst == bss_conf->cqm_rssi_hyst)
+                return 0;
+
+        bss_conf->cqm_rssi_thold = rssi_thold;
+        bss_conf->cqm_rssi_hyst = rssi_hyst;
+
+        /* tell the driver upon association, unless already associated */
+        if (sdata->u.mgd.associated)
+                ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_CQM);
+
+        return 0;
+}
+
 static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
                                       struct net_device *dev,
                                       const u8 *addr,
@@ -1506,4 +1532,5 @@ struct cfg80211_ops mac80211_config_ops = {
         .remain_on_channel = ieee80211_remain_on_channel,
         .cancel_remain_on_channel = ieee80211_cancel_remain_on_channel,
         .action = ieee80211_action,
+        .set_cqm_rssi_config = ieee80211_set_cqm_rssi_config,
 };
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 865ea1cfb7b..65eafda5738 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -750,6 +750,11 @@ static void ieee80211_set_associated(struct ieee80211_sub_if_data *sdata,
         /* And the BSSID changed - we're associated now */
         bss_info_changed |= BSS_CHANGED_BSSID;
 
+        /* Tell the driver to monitor connection quality (if supported) */
+        if ((local->hw.flags & IEEE80211_HW_SUPPORTS_CQM_RSSI) &&
+            sdata->vif.bss_conf.cqm_rssi_thold)
+                bss_info_changed |= BSS_CHANGED_CQM;
+
         ieee80211_bss_info_change_notify(sdata, bss_info_changed);
 
         mutex_lock(&local->iflist_mtx);
@@ -2182,3 +2187,13 @@ int ieee80211_mgd_action(struct ieee80211_sub_if_data *sdata,
         *cookie = (unsigned long) skb;
         return 0;
 }
+
+void ieee80211_cqm_rssi_notify(struct ieee80211_vif *vif,
+                               enum nl80211_cqm_rssi_threshold_event rssi_event,
+                               gfp_t gfp)
+{
+        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+
+        cfg80211_cqm_rssi_notify(sdata->dev, rssi_event, gfp);
+}
+EXPORT_SYMBOL(ieee80211_cqm_rssi_notify);