wifi: cfg80211: Handle specific BSSID in 6GHz scanning

When the scan parameters for a 6GHz scan specify a unicast
BSSID address, and the corresponding AP is found in the scan
list, add a corresponding entry in the collocated AP list,
so this AP would be directly probed even if it was not
advertised as a collocated AP.

This is needed for handling a scan request that is intended
for a ML probe flow, where user space can requests a scan
to retrieve information for other links in the AP MLD.
Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230928172905.54b954bc02ad.I1c072793d3d77a4c8fbbc64b4db5cce1bbb00382@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/scan.c

@@ -830,10 +830,47 @@ static int cfg80211_scan_6ghz(struct cfg80211_registered_device *rdev)
 		list_for_each_entry(intbss, &rdev->bss_list, list) {
 			struct cfg80211_bss *res = &intbss->pub;
 			const struct cfg80211_bss_ies *ies;
+			const struct element *ssid_elem;
+			struct cfg80211_colocated_ap *entry;
+			u32 s_ssid_tmp;
+			int ret;
 
 			ies = rcu_access_pointer(res->ies);
 			count += cfg80211_parse_colocated_ap(ies,
 							     &coloc_ap_list);
+
+			/* In case the scan request specified a specific BSSID
+			 * and the BSS is found and operating on 6GHz band then
+			 * add this AP to the collocated APs list.
+			 * This is relevant for ML probe requests when the lower
+			 * band APs have not been discovered.
+			 */
+			if (is_broadcast_ether_addr(rdev_req->bssid) ||
+			    !ether_addr_equal(rdev_req->bssid, res->bssid) ||
+			    res->channel->band != NL80211_BAND_6GHZ)
+				continue;
+
+			ret = cfg80211_calc_short_ssid(ies, &ssid_elem,
+						       &s_ssid_tmp);
+			if (ret)
+				continue;
+
+			entry = kzalloc(sizeof(*entry) + IEEE80211_MAX_SSID_LEN,
+					GFP_ATOMIC);
+
+			if (!entry)
+				continue;
+
+			memcpy(entry->bssid, res->bssid, ETH_ALEN);
+			entry->short_ssid = s_ssid_tmp;
+			memcpy(entry->ssid, ssid_elem->data,
+			       ssid_elem->datalen);
+			entry->ssid_len = ssid_elem->datalen;
+			entry->short_ssid_valid = true;
+			entry->center_freq = res->channel->center_freq;
+
+			list_add_tail(&entry->list, &coloc_ap_list);
+			count++;
 		}
 		spin_unlock_bh(&rdev->bss_lock);
 	}