cfg80211: Accept multiple RSSI thresholds for CQM

Change the SET CQM command's RSSI threshold attribute to accept any
number of thresholds as a sorted array.  The API should be backwards
compatible so that if one s32 threshold value is passed, the old
mechanism is enabled.  The netlink event generated is the same in both
cases.

cfg80211 handles an arbitrary number of RSSI thresholds but drivers have
to provide a method (set_cqm_rssi_range_config) that configures a range
set by a high and a low value.  Drivers have to call back when the RSSI
goes out of that range and there's no additional event for each time the
range is reconfigured as there was with the current one-threshold API.

This method doesn't have a hysteresis parameter because there's no
benefit to the cfg80211 code from having the hysteresis be handled by
hardware/driver in terms of the number of wakeups.  At the same time
it would likely be less consistent between drivers if offloaded or
done in the drivers.

Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

5 files changed, 177 insertions, 13 deletions

diff --git a/net/wireless/core.c b/net/wireless/core.c
index e55e05bc4805..04143df20f7f 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -954,6 +954,12 @@ void wiphy_rfkill_set_hw_state(struct wiphy *wiphy, bool blocked)
 }
 EXPORT_SYMBOL(wiphy_rfkill_set_hw_state);
 
+void cfg80211_cqm_config_free(struct wireless_dev *wdev)
+{
+	kfree(wdev->cqm_config);
+	wdev->cqm_config = NULL;
+}
+
 void cfg80211_unregister_wdev(struct wireless_dev *wdev)
 {
 	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
@@ -980,6 +986,8 @@ void cfg80211_unregister_wdev(struct wireless_dev *wdev)
 		WARN_ON_ONCE(1);
 		break;
 	}
+
+	cfg80211_cqm_config_free(wdev);
 }
 EXPORT_SYMBOL(cfg80211_unregister_wdev);
 
@@ -1234,6 +1242,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 			kzfree(wdev->wext.keys);
 #endif
 			flush_work(&wdev->disconnect_wk);
+			cfg80211_cqm_config_free(wdev);
 		}
 		/*
 		 * synchronise (so that we won't find this netdev
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 58ca206982fe..efa690a7ef8d 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -272,6 +272,13 @@ struct cfg80211_iface_destroy {
 	u32 nlportid;
 };
 
+struct cfg80211_cqm_config {
+	u32 rssi_hyst;
+	s32 last_rssi_event_value;
+	int n_rssi_thresholds;
+	s32 rssi_thresholds[0];
+};
+
 void cfg80211_destroy_ifaces(struct cfg80211_registered_device *rdev);
 
 /* free object */
@@ -512,4 +519,6 @@ void cfg80211_stop_nan(struct cfg80211_registered_device *rdev,
 #define CFG80211_DEV_WARN_ON(cond)	({bool __r = (cond); __r; })
 #endif
 
+void cfg80211_cqm_config_free(struct wireless_dev *wdev);
+
 #endif /* __NET_WIRELESS_CORE_H */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d7f8be4e321a..d516527fcb8e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -9473,7 +9473,7 @@ static int nl80211_get_power_save(struct sk_buff *skb, struct genl_info *info)
 
 static const struct nla_policy
 nl80211_attr_cqm_policy[NL80211_ATTR_CQM_MAX + 1] = {
-	[NL80211_ATTR_CQM_RSSI_THOLD] = { .type = NLA_U32 },
+	[NL80211_ATTR_CQM_RSSI_THOLD] = { .type = NLA_BINARY },
 	[NL80211_ATTR_CQM_RSSI_HYST] = { .type = NLA_U32 },
 	[NL80211_ATTR_CQM_RSSI_THRESHOLD_EVENT] = { .type = NLA_U32 },
 	[NL80211_ATTR_CQM_TXE_RATE] = { .type = NLA_U32 },
@@ -9502,28 +9502,123 @@ static int nl80211_set_cqm_txe(struct genl_info *info,
 	return rdev_set_cqm_txe_config(rdev, dev, rate, pkts, intvl);
 }
 
+static int cfg80211_cqm_rssi_update(struct cfg80211_registered_device *rdev,
+				    struct net_device *dev)
+{
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	s32 last, low, high;
+	u32 hyst;
+	int i, n;
+	int err;
+
+	/* RSSI reporting disabled? */
+	if (!wdev->cqm_config)
+		return rdev_set_cqm_rssi_range_config(rdev, dev, 0, 0);
+
+	/*
+	 * Obtain current RSSI value if possible, if not and no RSSI threshold
+	 * event has been received yet, we should receive an event after a
+	 * connection is established and enough beacons received to calculate
+	 * the average.
+	 */
+	if (!wdev->cqm_config->last_rssi_event_value && wdev->current_bss &&
+	    rdev->ops->get_station) {
+		struct station_info sinfo;
+		u8 *mac_addr;
+
+		mac_addr = wdev->current_bss->pub.bssid;
+
+		err = rdev_get_station(rdev, dev, mac_addr, &sinfo);
+		if (err)
+			return err;
+
+		if (sinfo.filled & BIT(NL80211_STA_INFO_BEACON_SIGNAL_AVG))
+			wdev->cqm_config->last_rssi_event_value =
+				(s8) sinfo.rx_beacon_signal_avg;
+	}
+
+	last = wdev->cqm_config->last_rssi_event_value;
+	hyst = wdev->cqm_config->rssi_hyst;
+	n = wdev->cqm_config->n_rssi_thresholds;
+
+	for (i = 0; i < n; i++)
+		if (last < wdev->cqm_config->rssi_thresholds[i])
+			break;
+
+	low = i > 0 ?
+		(wdev->cqm_config->rssi_thresholds[i - 1] - hyst) : S32_MIN;
+	high = i < n ?
+		(wdev->cqm_config->rssi_thresholds[i] + hyst - 1) : S32_MAX;
+
+	return rdev_set_cqm_rssi_range_config(rdev, dev, low, high);
+}
+
 static int nl80211_set_cqm_rssi(struct genl_info *info,
-				s32 threshold, u32 hysteresis)
+				const s32 *thresholds, int n_thresholds,
+				u32 hysteresis)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	int i, err;
+	s32 prev = S32_MIN;
 
-	if (threshold > 0)
-		return -EINVAL;
-
-	/* disabling - hysteresis should also be zero then */
-	if (threshold == 0)
-		hysteresis = 0;
+	/* Check all values negative and sorted */
+	for (i = 0; i < n_thresholds; i++) {
+		if (thresholds[i] > 0 || thresholds[i] <= prev)
+			return -EINVAL;
 
-	if (!rdev->ops->set_cqm_rssi_config)
-		return -EOPNOTSUPP;
+		prev = thresholds[i];
+	}
 
 	if (wdev->iftype != NL80211_IFTYPE_STATION &&
 	    wdev->iftype != NL80211_IFTYPE_P2P_CLIENT)
 		return -EOPNOTSUPP;
 
-	return rdev_set_cqm_rssi_config(rdev, dev, threshold, hysteresis);
+	wdev_lock(wdev);
+	cfg80211_cqm_config_free(wdev);
+	wdev_unlock(wdev);
+
+	if (n_thresholds <= 1 && rdev->ops->set_cqm_rssi_config) {
+		if (n_thresholds == 0 || thresholds[0] == 0) /* Disabling */
+			return rdev_set_cqm_rssi_config(rdev, dev, 0, 0);
+
+		return rdev_set_cqm_rssi_config(rdev, dev,
+						thresholds[0], hysteresis);
+	}
+
+	if (!wiphy_ext_feature_isset(&rdev->wiphy,
+				     NL80211_EXT_FEATURE_CQM_RSSI_LIST))
+		return -EOPNOTSUPP;
+
+	if (n_thresholds == 1 && thresholds[0] == 0) /* Disabling */
+		n_thresholds = 0;
+
+	wdev_lock(wdev);
+	if (n_thresholds) {
+		struct cfg80211_cqm_config *cqm_config;
+
+		cqm_config = kzalloc(sizeof(struct cfg80211_cqm_config) +
+				     n_thresholds * sizeof(s32), GFP_KERNEL);
+		if (!cqm_config) {
+			err = -ENOMEM;
+			goto unlock;
+		}
+
+		cqm_config->rssi_hyst = hysteresis;
+		cqm_config->n_rssi_thresholds = n_thresholds;
+		memcpy(cqm_config->rssi_thresholds, thresholds,
+		       n_thresholds * sizeof(s32));
+
+		wdev->cqm_config = cqm_config;
+	}
+
+	err = cfg80211_cqm_rssi_update(rdev, dev);
+
+unlock:
+	wdev_unlock(wdev);
+
+	return err;
 }
 
 static int nl80211_set_cqm(struct sk_buff *skb, struct genl_info *info)
@@ -9543,10 +9638,16 @@ static int nl80211_set_cqm(struct sk_buff *skb, struct genl_info *info)
 
 	if (attrs[NL80211_ATTR_CQM_RSSI_THOLD] &&
 	    attrs[NL80211_ATTR_CQM_RSSI_HYST]) {
-		s32 threshold = nla_get_s32(attrs[NL80211_ATTR_CQM_RSSI_THOLD]);
+		const s32 *thresholds =
+			nla_data(attrs[NL80211_ATTR_CQM_RSSI_THOLD]);
+		int len = nla_len(attrs[NL80211_ATTR_CQM_RSSI_THOLD]);
 		u32 hysteresis = nla_get_u32(attrs[NL80211_ATTR_CQM_RSSI_HYST]);
 
-		return nl80211_set_cqm_rssi(info, threshold, hysteresis);
+		if (len % 4)
+			return -EINVAL;
+
+		return nl80211_set_cqm_rssi(info, thresholds, len / 4,
+					    hysteresis);
 	}
 
 	if (attrs[NL80211_ATTR_CQM_TXE_RATE] &&
@@ -13983,6 +14084,8 @@ void cfg80211_cqm_rssi_notify(struct net_device *dev,
 			      s32 rssi_level, gfp_t gfp)
 {
 	struct sk_buff *msg;
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
 
 	trace_cfg80211_cqm_rssi_notify(dev, rssi_event, rssi_level);
 
@@ -13990,6 +14093,15 @@ void cfg80211_cqm_rssi_notify(struct net_device *dev,
 		    rssi_event != NL80211_CQM_RSSI_THRESHOLD_EVENT_HIGH))
 		return;
 
+	if (wdev->cqm_config) {
+		wdev->cqm_config->last_rssi_event_value = rssi_level;
+
+		cfg80211_cqm_rssi_update(rdev, dev);
+
+		if (rssi_level == 0)
+			rssi_level = wdev->cqm_config->last_rssi_event_value;
+	}
+
 	msg = cfg80211_prepare_cqm(dev, NULL, gfp);
 	if (!msg)
 		return;
diff --git a/net/wireless/rdev-ops.h b/net/wireless/rdev-ops.h
index 2f425075ada8..f2baf5921091 100644
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -750,6 +750,18 @@ rdev_set_cqm_rssi_config(struct cfg80211_registered_device *rdev,
 }
 
 static inline int
+rdev_set_cqm_rssi_range_config(struct cfg80211_registered_device *rdev,
+			       struct net_device *dev, s32 low, s32 high)
+{
+	int ret;
+	trace_rdev_set_cqm_rssi_range_config(&rdev->wiphy, dev, low, high);
+	ret = rdev->ops->set_cqm_rssi_range_config(&rdev->wiphy, dev,
+						   low, high);
+	trace_rdev_return_int(&rdev->wiphy, ret);
+	return ret;
+}
+
+static inline int
 rdev_set_cqm_txe_config(struct cfg80211_registered_device *rdev,
 			struct net_device *dev, u32 rate, u32 pkts, u32 intvl)
 {
diff --git a/net/wireless/trace.h b/net/wireless/trace.h
index 776e80cef9b4..fd55786f0462 100644
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -1322,6 +1322,28 @@ TRACE_EVENT(rdev_set_cqm_rssi_config,
 		 __entry->rssi_thold, __entry->rssi_hyst)
 );
 
+TRACE_EVENT(rdev_set_cqm_rssi_range_config,
+	TP_PROTO(struct wiphy *wiphy,
+		 struct net_device *netdev, s32 low, s32 high),
+	TP_ARGS(wiphy, netdev, low, high),
+	TP_STRUCT__entry(
+		WIPHY_ENTRY
+		NETDEV_ENTRY
+		__field(s32, rssi_low)
+		__field(s32, rssi_high)
+	),
+	TP_fast_assign(
+		WIPHY_ASSIGN;
+		NETDEV_ASSIGN;
+		__entry->rssi_low = low;
+		__entry->rssi_high = high;
+	),
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT
+		  ", range: %d - %d ",
+		  WIPHY_PR_ARG, NETDEV_PR_ARG,
+		  __entry->rssi_low, __entry->rssi_high)
+);
+
 TRACE_EVENT(rdev_set_cqm_txe_config,
 	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev, u32 rate,
 		 u32 pkts, u32 intvl),