wifi: cfg80211: set correct param change count in ML element

The ML element generation code to create a BSS entry from a per-STA
profile was not overwriting the BSS parameter change count. This meant
that the incorrect parameter change count would be reported within the
multi-link element.

Fix this by returning the BSS parameter change count from the function
and placing it into the ML element. The returned tbtt info was never
used, so just drop that to simplify the code.

Fixes: 5f478adf ("wifi: cfg80211: generate an ML element for per-STA profiles")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240216135047.f2a507634692.I06b122c7a319a38b4e970f5e0bd3d3ef9cac4cbe@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/scan.c

@@ -2567,9 +2567,9 @@ cfg80211_defrag_mle(const struct element *mle, const u8 *ie, size_t ielen,
 }
 
 static u8
-cfg80211_tbtt_info_for_mld_ap(const u8 *ie, size_t ielen, u8 mld_id, u8 link_id,
-			      const struct ieee80211_neighbor_ap_info **ap_info,
-			      const u8 **tbtt_info)
+cfg80211_rnr_info_for_mld_ap(const u8 *ie, size_t ielen, u8 mld_id, u8 link_id,
+			     const struct ieee80211_neighbor_ap_info **ap_info,
+			     u8 *param_ch_count)
 {
 	const struct ieee80211_neighbor_ap_info *info;
 	const struct element *rnr;
@@ -2626,7 +2626,9 @@ cfg80211_tbtt_info_for_mld_ap(const u8 *ie, size_t ielen, u8 mld_id, u8 link_id,
 				if (mld_id == mld_params->mld_id &&
 				    link_id == lid) {
 					*ap_info = info;
-					*tbtt_info = pos;
+					*param_ch_count =
+						le16_get_bits(mld_params->params,
+							      IEEE80211_RNR_MLD_PARAMS_BSS_CHANGE_COUNT);
 
 					return use_for;
 				}
@@ -2836,8 +2838,8 @@ cfg80211_parse_ml_elem_sta_data(struct wiphy *wiphy,
 		enum nl80211_band band;
 		u32 freq;
 		const u8 *profile;
-		const u8 *tbtt_info;
 		ssize_t profile_len;
+		u8 param_ch_count;
 		u8 link_id, use_for;
 
 		if (!ieee80211_mle_basic_sta_prof_size_ok((u8 *)mle->sta_prof[i],
@@ -2880,10 +2882,11 @@ cfg80211_parse_ml_elem_sta_data(struct wiphy *wiphy,
 		profile_len -= 2;
 
 		/* Find in RNR to look up channel information */
-		use_for = cfg80211_tbtt_info_for_mld_ap(tx_data->ie,
-							tx_data->ielen,
-							mld_id, link_id,
-							&ap_info, &tbtt_info);
+		use_for = cfg80211_rnr_info_for_mld_ap(tx_data->ie,
+						       tx_data->ielen,
+						       mld_id, link_id,
+						       &ap_info,
+						       &param_ch_count);
 		if (!use_for)
 			continue;
 
@@ -2926,7 +2929,8 @@ cfg80211_parse_ml_elem_sta_data(struct wiphy *wiphy,
 			continue;
 
 		/* Copy the Basic Multi-Link element including the common
-		 * information, and then fix up the link ID.
+		 * information, and then fix up the link ID and BSS param
+		 * change count.
 		 * Note that the ML element length has been verified and we
 		 * also checked that it contains the link ID.
 		 */
@@ -2937,6 +2941,8 @@ cfg80211_parse_ml_elem_sta_data(struct wiphy *wiphy,
 		       sizeof(*ml_elem) + ml_common_len);
 
 		new_ie[data.ielen + sizeof(*ml_elem) + 1 + ETH_ALEN] = link_id;
+		new_ie[data.ielen + sizeof(*ml_elem) + 1 + ETH_ALEN + 1] =
+			param_ch_count;
 
 		data.ielen += sizeof(*ml_elem) + ml_common_len;