nl80211: add support for BSSIDs in scheduled scan matchsets

This patch allows for the scheduled scan request to specify matchsets
for specific BSSIDs.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
[docs, netlink policy fix]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -1613,11 +1613,15 @@ static inline void get_random_mask_addr(u8 *buf, const u8 *addr, const u8 *mask)
 /**
  * struct cfg80211_match_set - sets of attributes to match
  *
- * @ssid: SSID to be matched; may be zero-length for no match (RSSI only)
+ * @ssid: SSID to be matched; may be zero-length in case of BSSID match
+ *	or no match (RSSI only)
+ * @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)
  */
 struct cfg80211_match_set {
 	struct cfg80211_ssid ssid;
+	u8 bssid[ETH_ALEN];
 	s32 rssi_thold;
 };
 

include/uapi/linux/nl80211.h

@@ -3194,6 +3194,7 @@ enum nl80211_reg_rule_attr {
  * @__NL80211_SCHED_SCAN_MATCH_ATTR_INVALID: attribute number 0 is reserved
  * @NL80211_SCHED_SCAN_MATCH_ATTR_SSID: SSID to be used for matching,
  *	only report BSS with matching SSID.
+ *	(This cannot be used together with BSSID.)
  * @NL80211_SCHED_SCAN_MATCH_ATTR_RSSI: RSSI threshold (in dBm) for reporting a
  *	BSS in scan results. Filtering is turned off if not specified. Note that
  *	if this attribute is in a match set of its own, then it is treated as
@@ -3209,6 +3210,8 @@ enum nl80211_reg_rule_attr {
  *	BSS-es in the specified band is to be adjusted before doing
  *	RSSI-based BSS selection. The attribute value is a packed structure
  *	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_ATTR_MAX: highest scheduled scan filter
  *	attribute number currently defined
  * @__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST: internal use
@@ -3220,6 +3223,7 @@ enum nl80211_sched_scan_match_attr {
 	NL80211_SCHED_SCAN_MATCH_ATTR_RSSI,
 	NL80211_SCHED_SCAN_MATCH_ATTR_RELATIVE_RSSI,
 	NL80211_SCHED_SCAN_MATCH_ATTR_RSSI_ADJUST,
+	NL80211_SCHED_SCAN_MATCH_ATTR_BSSID,
 
 	/* keep last */
 	__NL80211_SCHED_SCAN_MATCH_ATTR_AFTER_LAST,

net/wireless/nl80211.c

@@ -497,6 +497,7 @@ 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 },
 };
 
@@ -7036,8 +7037,15 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 					       NULL);
 			if (err)
 				return ERR_PTR(err);
+
+			/* SSID and BSSID are mutually exclusive */
+			if (tb[NL80211_SCHED_SCAN_MATCH_ATTR_SSID] &&
+			    tb[NL80211_SCHED_SCAN_MATCH_ATTR_BSSID])
+				return ERR_PTR(-EINVAL);
+
 			/* add other standalone attributes here */
-			if (tb[NL80211_SCHED_SCAN_MATCH_ATTR_SSID]) {
+			if (tb[NL80211_SCHED_SCAN_MATCH_ATTR_SSID] ||
+			    tb[NL80211_SCHED_SCAN_MATCH_ATTR_BSSID]) {
 				n_match_sets++;
 				continue;
 			}
@@ -7208,7 +7216,7 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 		nla_for_each_nested(attr,
 				    attrs[NL80211_ATTR_SCHED_SCAN_MATCH],
 				    tmp) {
-			struct nlattr *ssid, *rssi;
+			struct nlattr *ssid, *bssid, *rssi;
 
 			err = nla_parse_nested(tb,
 					       NL80211_SCHED_SCAN_MATCH_ATTR_MAX,
@@ -7217,7 +7225,8 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 			if (err)
 				goto out_free;
 			ssid = tb[NL80211_SCHED_SCAN_MATCH_ATTR_SSID];
-			if (ssid) {
+			bssid = tb[NL80211_SCHED_SCAN_MATCH_ATTR_BSSID];
+			if (ssid || bssid) {
 				if (WARN_ON(i >= n_match_sets)) {
 					/* this indicates a programming error,
 					 * the loop above should have verified
@@ -7227,14 +7236,25 @@ nl80211_parse_sched_scan(struct wiphy *wiphy, struct wireless_dev *wdev,
 					goto out_free;
 				}
 
-				if (nla_len(ssid) > IEEE80211_MAX_SSID_LEN) {
-					err = -EINVAL;
-					goto out_free;
+				if (ssid) {
+					if (nla_len(ssid) > IEEE80211_MAX_SSID_LEN) {
+						err = -EINVAL;
+						goto out_free;
+					}
+					memcpy(request->match_sets[i].ssid.ssid,
+					       nla_data(ssid), nla_len(ssid));
+					request->match_sets[i].ssid.ssid_len =
+						nla_len(ssid);
 				}
-				memcpy(request->match_sets[i].ssid.ssid,
-				       nla_data(ssid), nla_len(ssid));
-				request->match_sets[i].ssid.ssid_len =
-					nla_len(ssid);
+				if (bssid) {
+					if (nla_len(bssid) != ETH_ALEN) {
+						err = -EINVAL;
+						goto out_free;
+					}
+					memcpy(request->match_sets[i].bssid,
+					       nla_data(bssid), ETH_ALEN);
+				}
+
 				/* special attribute - old implementation w/a */
 				request->match_sets[i].rssi_thold =
 					default_match_rssi;