STA: Update scan results when BSS entry with current SSID is not found

wpa_supplicant might use a wrong BSS entry with the SSID different from
the current SSID of the current BSS while processing a roam event from
the driver when wpa_supplicant has a stale BSS entry with the old SSID
and the driver roams to the same BSS after it is restarted with a new
SSID.

To avoid this, update scan results from the driver when a BSS entry is
not found with the current SSID and try to fetch the BSS entry again
with the current SSID after this.

Also, with this change wpa_supplicant_get_new_bss() itself will update
the BSS table and search for the current BSS entry if it is not found in
the BSS table. So, remove the BSS table update and search logic from the
callers of wpa_supplicant_get_new_bss().

Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>

diff --git a/wpa_supplicant/events.c b/wpa_supplicant/events.c
index 447fc8fd805fa70acf593b915a9a7f90f59924ff..4ab9f0b88600c75ce978df38db938e233f3a9159 100644 (file)
--- a/wpa_supplicant/events.c
+++ b/wpa_supplicant/events.c
@@ -137,6 +137,33 @@ void wpas_network_reenabled(void *eloop_ctx, void *timeout_ctx)
 }
 
 
+static struct wpa_bss * __wpa_supplicant_get_new_bss(
+       struct wpa_supplicant *wpa_s, const u8 *bssid, const u8 *ssid,
+       size_t ssid_len)
+{
+       if (ssid && ssid_len > 0)
+               return wpa_bss_get(wpa_s, bssid, ssid, ssid_len);
+       else
+               return wpa_bss_get_bssid(wpa_s, bssid);
+}
+
+
+static struct wpa_bss * _wpa_supplicant_get_new_bss(
+       struct wpa_supplicant *wpa_s, const u8 *bssid, const u8 *ssid,
+       size_t ssid_len, bool try_update_scan_results)
+{
+       struct wpa_bss *bss = __wpa_supplicant_get_new_bss(wpa_s, bssid, ssid,
+                                                          ssid_len);
+
+       if (bss || !try_update_scan_results)
+               return bss;
+
+       wpa_supplicant_update_scan_results(wpa_s, bssid);
+
+       return __wpa_supplicant_get_new_bss(wpa_s, bssid, ssid, ssid_len);
+}
+
+
 static struct wpa_bss * wpa_supplicant_get_new_bss(
        struct wpa_supplicant *wpa_s, const u8 *bssid)
 {
@@ -144,14 +171,23 @@ static struct wpa_bss * wpa_supplicant_get_new_bss(
        struct wpa_ssid *ssid = wpa_s->current_ssid;
        u8 drv_ssid[SSID_MAX_LEN];
        int res;
+       bool try_update_scan_results = true;
 
        res = wpa_drv_get_ssid(wpa_s, drv_ssid);
-       if (res > 0)
-               bss = wpa_bss_get(wpa_s, bssid, drv_ssid, res);
-       if (!bss && ssid && ssid->ssid_len > 0)
-               bss = wpa_bss_get(wpa_s, bssid, ssid->ssid, ssid->ssid_len);
+       if (res > 0) {
+               bss = _wpa_supplicant_get_new_bss(wpa_s, bssid, drv_ssid, res,
+                                                 try_update_scan_results);
+               try_update_scan_results = false;
+       }
+       if (!bss && ssid && ssid->ssid_len > 0) {
+               bss = _wpa_supplicant_get_new_bss(wpa_s, bssid, ssid->ssid,
+                                                 ssid->ssid_len,
+                                                 try_update_scan_results);
+               try_update_scan_results = false;
+       }
        if (!bss)
-               bss = wpa_bss_get_bssid(wpa_s, bssid);
+               bss = _wpa_supplicant_get_new_bss(wpa_s, bssid, NULL, 0,
+                                                 try_update_scan_results);
 
        return bss;
 }
@@ -162,13 +198,6 @@ wpa_supplicant_update_current_bss(struct wpa_supplicant *wpa_s, const u8 *bssid)
 {
        struct wpa_bss *bss = wpa_supplicant_get_new_bss(wpa_s, bssid);
 
-       if (!bss) {
-               wpa_supplicant_update_scan_results(wpa_s, bssid);
-
-               /* Get the BSS from the new scan results */
-               bss = wpa_supplicant_get_new_bss(wpa_s, bssid);
-       }
-
        if (bss)
                wpa_s->current_bss = bss;
 
@@ -181,11 +210,6 @@ static void wpa_supplicant_update_link_bss(struct wpa_supplicant *wpa_s,
 {
        struct wpa_bss *bss = wpa_supplicant_get_new_bss(wpa_s, bssid);
 
-       if (!bss) {
-               wpa_supplicant_update_scan_results(wpa_s, bssid);
-               bss = wpa_supplicant_get_new_bss(wpa_s, bssid);
-       }
-
        if (bss)
                wpa_s->links[link_id].bss = bss;
 }
@@ -4053,13 +4077,6 @@ static int wpa_sm_set_ml_info(struct wpa_supplicant *wpa_s)
                struct wpa_bss *bss;
 
                bss = wpa_supplicant_get_new_bss(wpa_s, drv_mlo.links[i].bssid);
-               if (!bss) {
-                       wpa_supplicant_update_scan_results(
-                               wpa_s, drv_mlo.links[i].bssid);
-                       bss = wpa_supplicant_get_new_bss(
-                               wpa_s, drv_mlo.links[i].bssid);
-               }
-
                if (!bss) {
                        wpa_dbg(wpa_s, MSG_INFO,
                                "Failed to get MLO link %d BSS", i);