nl80211/cfg80211: Specify band specific min RSSI thresholds with sched scan

This commit adds the support to specify the RSSI thresholds per
band for each match set. This enhances the current behavior which
specifies a single rssi_threshold across all the bands by
introducing the rssi_threshold_per_band. These per band rssi
thresholds are referred through NL80211_BAND_* (enum nl80211_band)
variables  as attribute types. Such attributes/values per each
band are nested through NL80211_ATTR_SCHED_SCAN_MIN_RSSI.
These band specific rssi thresholds shall take precedence over
the current rssi_thold per match set.
Drivers indicate this support through
%NL80211_EXT_FEATURE_SCHED_SCAN_BAND_SPECIFIC_RSSI_THOLD.
These per band rssi attributes/values does not specify
"default RSSI filter" as done by
NL80211_SCHED_SCAN_MATCH_ATTR_RSSI to stay backward compatible.
That said, these per band rssi values have to be specified for
the corresponding matchset.
Signed-off-by: Nvamsi krishna <vamsin@codeaurora.org>
Signed-off-by: NSrinivas Dasari <dasaris@codeaurora.org>
[rebase on refactoring, add policy]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1832,11 +1832,19 @@ static inline void get_random_mask_addr(u8 *buf, const u8 *addr, const u8 *mask)
  * @bssid: BSSID to be matched; may be all-zero BSSID in case of SSID match
  *	or no match (RSSI only)
  * @rssi_thold: don't report scan results below this threshold (in s32 dBm)
+ * @per_band_rssi_thold: Minimum rssi threshold for each band to be applied
+ *	for filtering out scan results received. Drivers advertize this support
+ *	of band specific rssi based filtering through the feature capability
+ *	%NL80211_EXT_FEATURE_SCHED_SCAN_BAND_SPECIFIC_RSSI_THOLD. These band
+ *	specific rssi thresholds take precedence over rssi_thold, if specified.
+ *	If not specified for any band, it will be assigned with rssi_thold of
+ *	corresponding matchset.
  */
 struct cfg80211_match_set {
 	struct cfg80211_ssid ssid;
 	u8 bssid[ETH_ALEN];
 	s32 rssi_thold;
+	s32 per_band_rssi_thold[NUM_NL80211_BANDS];
 };
 
 /**

include/uapi/linux/nl80211.h

@@ -3638,6 +3638,14 @@ enum nl80211_reg_rule_attr {
  *	value as specified by &struct nl80211_bss_select_rssi_adjust.
  * @NL80211_SCHED_SCAN_MATCH_ATTR_BSSID: BSSID to be used for matching
  *	(this cannot be used together with SSID).
+ * @NL80211_SCHED_SCAN_MATCH_PER_BAND_RSSI: Nested attribute that carries the
+ *	band specific minimum rssi thresholds for the bands defined in
+ *	enum nl80211_band. The minimum rssi threshold value(s32) specific to a
+ *	band shall be encapsulated in attribute with type value equals to one
+ *	of the NL80211_BAND_* defined in enum nl80211_band. For example, the
+ *	minimum rssi threshold value for 2.4GHZ band shall be encapsulated
+ *	within an attribute of type NL80211_BAND_2GHZ. And one or more of such
+ *	attributes will be nested within this attribute.
  * @NL80211_SCHED_SCAN_MATCH_ATTR_MAX: highest scheduled scan filter
  *	attribute number currently defined
  * @__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST: internal use
@@ -3650,6 +3658,7 @@ enum nl80211_sched_scan_match_attr {
 	NL80211_SCHED_SCAN_MATCH_ATTR_RELATIVE_RSSI,
 	NL80211_SCHED_SCAN_MATCH_ATTR_RSSI_ADJUST,
 	NL80211_SCHED_SCAN_MATCH_ATTR_BSSID,
+	NL80211_SCHED_SCAN_MATCH_PER_BAND_RSSI,
 
 	/* keep last */
 	__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST,
@@ -5343,6 +5352,9 @@ enum nl80211_feature_flags {
  * @NL80211_EXT_FEATURE_AP_PMKSA_CACHING: Driver/device supports PMKSA caching
  *	(set/del PMKSA operations) in AP mode.
  *
+ * @NL80211_EXT_FEATURE_SCHED_SCAN_BAND_SPECIFIC_RSSI_THOLD: Driver supports
+ *	filtering of sched scan results using band specific RSSI thresholds.
+ *
  * @NUM_NL80211_EXT_FEATURES: number of extended features.
  * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
  */
@@ -5384,6 +5396,7 @@ enum nl80211_ext_feature_index {
 	NL80211_EXT_FEATURE_ENABLE_FTM_RESPONDER,
 	NL80211_EXT_FEATURE_AIRTIME_FAIRNESS,
 	NL80211_EXT_FEATURE_AP_PMKSA_CACHING,
+	NL80211_EXT_FEATURE_SCHED_SCAN_BAND_SPECIFIC_RSSI_THOLD,
 
 	/* add new features before the definition below */
 	NUM_NL80211_EXT_FEATURES,

net/wireless/nl80211.c

@@ -617,12 +617,21 @@ nl80211_rekey_policy[NUM_NL80211_REKEY_DATA] = {
 	[NL80211_REKEY_DATA_REPLAY_CTR] = { .len = NL80211_REPLAY_CTR_LEN },
 };
 
+static const struct nla_policy
+nl80211_match_band_rssi_policy[NUM_NL80211_BANDS] = {
+	[NL80211_BAND_2GHZ] = { .type = NLA_S32 },
+	[NL80211_BAND_5GHZ] = { .type = NLA_S32 },
+	[NL80211_BAND_60GHZ] = { .type = NLA_S32 },
+};
+
 static const struct nla_policy
 nl80211_match_policy[NL80211_SCHED_SCAN_MATCH_ATTR_MAX + 1] = {
 	[NL80211_SCHED_SCAN_MATCH_ATTR_SSID] = { .type = NLA_BINARY,
 						 .len = IEEE80211_MAX_SSID_LEN },
 	[NL80211_SCHED_SCAN_MATCH_ATTR_BSSID] = { .len = ETH_ALEN },
 	[NL80211_SCHED_SCAN_MATCH_ATTR_RSSI] = { .type = NLA_U32 },
+	[NL80211_SCHED_SCAN_MATCH_PER_BAND_RSSI] =
+		NLA_POLICY_NESTED(nl80211_match_band_rssi_policy),
 };
 
 static const struct nla_policy
@@ -7537,6 +7546,41 @@ nl80211_parse_sched_scan_plans(struct wiphy *wiphy, int n_plans,
 	return 0;
 }
 
+static int
+nl80211_parse_sched_scan_per_band_rssi(struct wiphy *wiphy,
+				       struct cfg80211_match_set *match_sets,
+				       struct nlattr *tb_band_rssi,
+				       s32 rssi_thold)
+{
+	struct nlattr *attr;
+	int i, tmp, ret = 0;
+
+	if (!wiphy_ext_feature_isset(wiphy,
+		    NL80211_EXT_FEATURE_SCHED_SCAN_BAND_SPECIFIC_RSSI_THOLD)) {
+		if (tb_band_rssi)
+			ret = -EOPNOTSUPP;
+		else
+			for (i = 0; i < NUM_NL80211_BANDS; i++)
+				match_sets->per_band_rssi_thold[i] =
+					NL80211_SCAN_RSSI_THOLD_OFF;
+		return ret;
+	}
+
+	for (i = 0; i < NUM_NL80211_BANDS; i++)
+		match_sets->per_band_rssi_thold[i] = rssi_thold;
+
+	nla_for_each_nested(attr, tb_band_rssi, tmp) {
+		enum nl80211_band band = nla_type(attr);
+
+		if (band < 0 || band >= NUM_NL80211_BANDS)
+			return -EINVAL;
+
+		match_sets->per_band_rssi_thold[band] =	nla_get_s32(attr);
+	}
+
+	return 0;
+}
+
 static struct cfg80211_sched_scan_request *
 nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 			 struct nlattr **attrs, int max_match_sets)
@@ -7816,6 +7860,15 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 			if (rssi)
 				request->match_sets[i].rssi_thold =
 					nla_get_s32(rssi);
+
+			/* Parse per band RSSI attribute */
+			err = nl80211_parse_sched_scan_per_band_rssi(wiphy,
+				&request->match_sets[i],
+				tb[NL80211_SCHED_SCAN_MATCH_PER_BAND_RSSI],
+				request->match_sets[i].rssi_thold);
+			if (err)
+				goto out_free;
+
 			i++;
 		}