qcacmn: Fix Connection issue when AP change from hidden to non-hidden

If AP change its status from hidden to broadcasting SSID in its beacon
kernel drop the beacon entry as its confusing. Now during connection
driver try to update the entry in kernel and it fails and as kernel drop
the beacon the connection fails.

To fix this detect if AP changed its ssid type from hidden to
broadcasting and unlink the old bss from kernel in that case.

Change-Id: I10ec42749ebcd2ddea23f7f3a94d862124df156d
CRs-Fixed: 2410430

os_if/linux/scan/inc/wlan_cfg80211_scan.h

@@ -261,6 +261,34 @@ wlan_cfg80211_inform_bss_frame_data(struct wiphy *wiphy,
 void wlan_cfg80211_inform_bss_frame(struct wlan_objmgr_pdev *pdev,
 	struct scan_cache_entry *scan_params);
 
+/**
+ * wlan_cfg80211_get_bss() - Get the bss entry matching the chan, bssid and ssid
+ * @wiphy: wiphy
+ * @channel: channel of the BSS to find
+ * @bssid: bssid of the BSS to find
+ * @ssid: ssid of the BSS to find
+ * @ssid_len: ssid len of of the BSS to find
+ *
+ * The API is a wrapper to get bss from kernel matching the chan,
+ * bssid and ssid
+ *
+ * Return: bss structure if found else NULL
+ */
+struct cfg80211_bss *wlan_cfg80211_get_bss(struct wiphy *wiphy,
+					   struct ieee80211_channel *channel,
+					   const u8 *bssid,
+					   const u8 *ssid, size_t ssid_len);
+
+/*
+ * wlan_cfg80211_unlink_bss_list : flush bss from the kernel cache
+ * @pdev: Pointer to pdev
+ * @scan_entry: scan entry
+ *
+ * Return: bss which is unlinked from kernel cache
+ */
+void wlan_cfg80211_unlink_bss_list(struct wlan_objmgr_pdev *pdev,
+				   struct scan_cache_entry *scan_entry);
+
 /**
  * wlan_vendor_abort_scan() - API to vendor abort scan
  * @pdev: Pointer to pdev

os_if/linux/scan/src/wlan_cfg80211_scan.c

@@ -1936,6 +1936,57 @@ void wlan_cfg80211_inform_bss_frame(struct wlan_objmgr_pdev *pdev,
 	qdf_mem_free(bss_data.mgmt);
 }
 
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 1, 0)) && \
+	!defined(WITH_BACKPORTS) && !defined(IEEE80211_PRIVACY)
+struct cfg80211_bss *wlan_cfg80211_get_bss(struct wiphy *wiphy,
+					   struct ieee80211_channel *channel,
+					   const u8 *bssid, const u8 *ssid,
+					   size_t ssid_len)
+{
+	return cfg80211_get_bss(wiphy, channel, bssid,
+				ssid, ssid_len,
+				WLAN_CAPABILITY_ESS,
+				WLAN_CAPABILITY_ESS);
+}
+#else
+struct cfg80211_bss *wlan_cfg80211_get_bss(struct wiphy *wiphy,
+					   struct ieee80211_channel *channel,
+					   const u8 *bssid, const u8 *ssid,
+					   size_t ssid_len)
+{
+	return cfg80211_get_bss(wiphy, channel, bssid,
+				ssid, ssid_len,
+				IEEE80211_BSS_TYPE_ESS,
+				IEEE80211_PRIVACY_ANY);
+}
+#endif
+
+void wlan_cfg80211_unlink_bss_list(struct wlan_objmgr_pdev *pdev,
+				   struct scan_cache_entry *scan_entry)
+{
+	struct cfg80211_bss *bss = NULL;
+	struct pdev_osif_priv *pdev_ospriv = wlan_pdev_get_ospriv(pdev);
+	struct wiphy *wiphy;
+
+	if (!pdev_ospriv) {
+		cfg80211_err("os_priv is NULL");
+		return;
+	}
+
+	wiphy = pdev_ospriv->wiphy;
+	bss = wlan_cfg80211_get_bss(wiphy, NULL, scan_entry->bssid.bytes,
+				    scan_entry->ssid.ssid,
+				    scan_entry->ssid.length);
+	if (!bss) {
+		cfg80211_err("BSS %pM not found", scan_entry->bssid.bytes);
+	} else {
+		cfg80211_debug("cfg80211_unlink_bss called for BSSID %pM",
+			       scan_entry->bssid.bytes);
+		cfg80211_unlink_bss(wiphy, bss);
+		wlan_cfg80211_put_bss(wiphy, bss);
+	}
+}
+
 #if (LINUX_VERSION_CODE < KERNEL_VERSION(4, 12, 0))
 /*
  * wlan_scan_wiphy_set_max_sched_scans() - set maximum number of scheduled scans

umac/scan/core/src/wlan_scan_cache_db.c

@@ -474,6 +474,8 @@ scm_update_mlme_info(struct scan_cache_entry *src,
 /**
  * scm_copy_info_from_dup_entry() - copy duplicate node info
  * to new scan entry
+ * @pdev: pdev ptr
+ * @scan_obj: scan obj ptr
  * @scan_db: scan database
  * @scan_params: new entry to be added
  * @scan_node: duplicate entry
@@ -483,7 +485,9 @@ scm_update_mlme_info(struct scan_cache_entry *src,
  * Return: void
  */
 static void
-scm_copy_info_from_dup_entry(struct scan_dbs *scan_db,
+scm_copy_info_from_dup_entry(struct wlan_objmgr_pdev *pdev,
+			     struct wlan_scan_obj *scan_obj,
+			     struct scan_dbs *scan_db,
 			     struct scan_cache_entry *scan_params,
 			     struct scan_cache_node *scan_node)
 {
@@ -491,6 +495,29 @@ scm_copy_info_from_dup_entry(struct scan_dbs *scan_db,
 	uint64_t time_gap;
 
 	scan_entry = scan_node->entry;
+
+	/* Update probe resp entry as well if AP is in hidden mode */
+	if (scan_params->frm_subtype == MGMT_SUBTYPE_PROBE_RESP &&
+	    scan_entry->is_hidden_ssid)
+		scan_params->is_hidden_ssid = true;
+
+	/*
+	 * If AP changed its beacon from not having an SSID to showing it the
+	 * kernel will drop the entry asumming that something is wrong with AP.
+	 * This can result in connection failure while updating the bss during
+	 * connection. So flush the hidden entry from kernel before indicating
+	 * the new entry.
+	 */
+	if (scan_entry->is_hidden_ssid &&
+	    scan_params->frm_subtype == MGMT_SUBTYPE_BEACON &&
+	    !util_scan_is_null_ssid(&scan_params->ssid)) {
+		if (scan_obj->cb.unlink_bss) {
+			scm_debug("Hidden AP %pM switch to non-hidden SSID, So unlink the entry",
+				  scan_entry->bssid.bytes);
+			scan_obj->cb.unlink_bss(pdev, scan_entry);
+		}
+	}
+
 	/* If old entry have the ssid but new entry does not */
 	if (util_scan_is_null_ssid(&scan_params->ssid) &&
 	    scan_entry->ssid.length) {
@@ -579,6 +606,8 @@ scm_copy_info_from_dup_entry(struct scan_dbs *scan_db,
  * scm_find_duplicate() - find duplicate entry,
  * if present, add input scan entry before it and delete
  * duplicate entry. otherwise add entry to tail
+ * @pdev: pdev ptr
+ * @scan_obj: scan obj ptr
  * @scan_db: scan db
  * @entry: input scan cache entry
  * @dup_node: node before which new entry to be added
@@ -589,7 +618,9 @@ scm_copy_info_from_dup_entry(struct scan_dbs *scan_db,
  * Return: bool
  */
 static bool
-scm_find_duplicate(struct scan_dbs *scan_db,
+scm_find_duplicate(struct wlan_objmgr_pdev *pdev,
+		   struct wlan_scan_obj *scan_obj,
+		   struct scan_dbs *scan_db,
 		   struct scan_cache_entry *entry,
 		   struct scan_cache_node **dup_node)
 {
@@ -606,7 +637,8 @@ scm_find_duplicate(struct scan_dbs *scan_db,
 	while (cur_node) {
 		if (util_is_scan_entry_match(entry,
 		   cur_node->entry)) {
-			scm_copy_info_from_dup_entry(scan_db, entry, cur_node);
+			scm_copy_info_from_dup_entry(pdev, scan_obj, scan_db,
+						     entry, cur_node);
 			*dup_node = cur_node;
 			return true;
 		}
@@ -661,7 +693,8 @@ static QDF_STATUS scm_add_update_entry(struct wlan_objmgr_psoc *psoc,
 		scm_debug("CSA IE present for BSSID: %pM",
 			  scan_params->bssid.bytes);
 
-	is_dup_found = scm_find_duplicate(scan_db, scan_params, &dup_node);
+	is_dup_found = scm_find_duplicate(pdev, scan_obj, scan_db, scan_params,
+					  &dup_node);
 
 	if (scan_obj->cb.inform_beacon)
 		scan_obj->cb.inform_beacon(pdev, scan_params);
@@ -1328,6 +1361,9 @@ QDF_STATUS scm_scan_register_bcn_cb(struct wlan_objmgr_psoc *psoc,
 	case SCAN_CB_TYPE_UPDATE_BCN:
 		scan_obj->cb.update_beacon = cb;
 		break;
+	case SCAN_CB_TYPE_UNLINK_BSS:
+		scan_obj->cb.unlink_bss = cb;
+		break;
 	default:
 		scm_err("invalid cb type %d", type);
 	}

umac/scan/core/src/wlan_scan_main.h

@@ -462,10 +462,12 @@ struct scan_default_params {
  * struct scan_cb - nif/sif function callbacks
  * @inform_beacon: cb to indicate frame to OS
  * @update_beacon: cb to indicate frame to MLME
+ * @unlink_bss: cb to unlink bss from kernel cache
  */
 struct scan_cb {
 	update_beacon_cb inform_beacon;
 	update_beacon_cb update_beacon;
+	update_beacon_cb unlink_bss;
 	/* Define nif/sif function callbacks here */
 };
 

umac/scan/dispatcher/inc/wlan_scan_public_structs.h

@@ -273,6 +273,7 @@ struct security_info {
  * @bssid: bssid
  * @mac_addr: mac address
  * @ssid: ssid
+ * @is_hidden_ssid: is AP having hidden ssid.
  * @seq_num: sequence number
  * @phy_mode: Phy mode of the AP
  * @avg_rssi: Average RSSI fof the AP
@@ -309,6 +310,7 @@ struct scan_cache_entry {
 	struct qdf_mac_addr bssid;
 	struct qdf_mac_addr mac_addr;
 	struct wlan_ssid ssid;
+	bool is_hidden_ssid;
 	uint16_t seq_num;
 	enum wlan_phymode phy_mode;
 	int32_t avg_rssi;
@@ -1139,12 +1141,14 @@ typedef void (*scan_event_handler) (struct wlan_objmgr_vdev *vdev,
  * enum scan_cb_type - update beacon cb type
  * @SCAN_CB_TYPE_INFORM_BCN: Calback to indicate beacon to OS
  * @SCAN_CB_TYPE_UPDATE_BCN: Calback to indicate beacon
+ * @SCAN_CB_TYPE_UNLINK_BSS: cb to unlink bss entry
  *                    to MLME and update MLME info
  *
  */
 enum scan_cb_type {
 	SCAN_CB_TYPE_INFORM_BCN,
 	SCAN_CB_TYPE_UPDATE_BCN,
+	SCAN_CB_TYPE_UNLINK_BSS,
 };
 
 /* Set PNO */

umac/scan/dispatcher/src/wlan_scan_utils_api.c

@@ -1097,6 +1097,7 @@ util_scan_gen_scan_entry(struct wlan_objmgr_pdev *pdev,
 
 	if (util_scan_is_hidden_ssid(ssid)) {
 		scan_entry->ie_list.ssid = NULL;
+		scan_entry->is_hidden_ssid = true;
 	} else {
 		qdf_mem_copy(scan_entry->ssid.ssid,
 				ssid->ssid, ssid->ssid_len);