cfg80211: Add support to sched scan to report better BSSs

Enhance sched scan to support option of finding a better BSS while in
connected state. Firmware scans the medium and reports when it finds a
known BSS which has better RSSI than the current connected BSS. New
attributes to specify the relative RSSI (compared to the current BSS)
are added to the sched scan to implement this.

Signed-off-by: vamsi krishna <vamsin@qti.qualcomm.com>
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-commit: bf95ecdba93b98d27ac219e79f773f2074b4ca47
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211-next.git
CRs-Fixed: 1112378
Change-Id: I0e3cf69ff6e0a73e23080a2d1e8ab9f51bcaba96

1 files changed, 44 insertions, 0 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c013ddc008ed..5ec8e5cf8a8e 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -404,6 +404,10 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_PBSS] = { .type = NLA_FLAG },
 	[NL80211_ATTR_BSS_SELECT] = { .type = NLA_NESTED },
 	[NL80211_ATTR_BSSID] = { .len = ETH_ALEN },
+	[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] = { .type = NLA_S8 },
+	[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST] = {
+		.len = sizeof(struct nl80211_bss_select_rssi_adjust)
+	},
 };
 
 /* policy for the key attributes */
@@ -6653,6 +6657,12 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 	if (!n_plans || n_plans > wiphy->max_sched_scan_plans)
 		return ERR_PTR(-EINVAL);
 
+	if (!wiphy_ext_feature_isset(
+		    wiphy, NL80211_EXT_FEATURE_SCHED_SCAN_RELATIVE_RSSI) &&
+	    (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI] ||
+	     attrs[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST]))
+		return ERR_PTR(-EINVAL);
+
 	request = kzalloc(sizeof(*request)
 			+ sizeof(*request->ssids) * n_ssids
 			+ sizeof(*request->match_sets) * n_match_sets
@@ -6858,6 +6868,26 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 		request->delay =
 			nla_get_u32(attrs[NL80211_ATTR_SCHED_SCAN_DELAY]);
 
+	if (attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI]) {
+		request->relative_rssi = nla_get_s8(
+			attrs[NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI]);
+		request->relative_rssi_set = true;
+	}
+
+	if (request->relative_rssi_set &&
+	    attrs[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST]) {
+		struct nl80211_bss_select_rssi_adjust *rssi_adjust;
+
+		rssi_adjust = nla_data(
+			attrs[NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST]);
+		request->rssi_adjust.band = rssi_adjust->band;
+		request->rssi_adjust.delta = rssi_adjust->delta;
+		if (!is_band_valid(wiphy, request->rssi_adjust.band)) {
+			err = -EINVAL;
+			goto out_free;
+		}
+	}
+
 	err = nl80211_parse_sched_scan_plans(wiphy, n_plans, request, attrs);
 	if (err)
 		goto out_free;
@@ -9356,6 +9386,20 @@ static int nl80211_send_wowlan_nd(struct sk_buff *msg,
 	if (nla_put_u32(msg, NL80211_ATTR_SCHED_SCAN_DELAY, req->delay))
 		return -ENOBUFS;
 
+	if (req->relative_rssi_set) {
+		struct nl80211_bss_select_rssi_adjust rssi_adjust;
+
+		if (nla_put_s8(msg, NL80211_ATTR_SCHED_SCAN_RELATIVE_RSSI,
+			       req->relative_rssi))
+			return -ENOBUFS;
+
+		rssi_adjust.band = req->rssi_adjust.band;
+		rssi_adjust.delta = req->rssi_adjust.delta;
+		if (nla_put(msg, NL80211_ATTR_SCHED_SCAN_RSSI_ADJUST,
+			    sizeof(rssi_adjust), &rssi_adjust))
+			return -ENOBUFS;
+	}
+
 	freqs = nla_nest_start(msg, NL80211_ATTR_SCAN_FREQUENCIES);
 	if (!freqs)
 		return -ENOBUFS;