nl80211: Prefer newer scan result over older during duplicate removal

Previously, it was possible for bss_info_handler() to end up dropping a
newer scan result entry if there were two entries with the same BSSID
and SSID (i.e., only frequency was different) and we were not associated
with either. This could happen, e.g., in some P2P use cases where device
discovery may happen on different channels. Fix this by checking the age
of the scan entries as well to prefer the most recent response.

Signed-hostap: Jouni Malinen <j@w1.fi>

diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
index fd4059c8388ef71c4bd7de0bf512d7f1619aabe8..58d6fd620874dfd1bb2556eadabe8201cf134573 100644 (file)
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -4996,7 +4996,8 @@ static int bss_info_handler(struct nl_msg *msg, void *arg)
         * BSSID,SSID pair is seen on multiple channels. wpa_supplicant does
         * not use frequency as a separate key in the BSS table, so filter out
         * duplicated entries. Prefer associated BSS entry in such a case in
-        * order to get the correct frequency into the BSS table.
+        * order to get the correct frequency into the BSS table. Similarly,
+        * prefer newer entries over older.
         */
        for (i = 0; i < res->num; i++) {
                const u8 *s1, *s2;
@@ -5014,8 +5015,9 @@ static int bss_info_handler(struct nl_msg *msg, void *arg)
                wpa_printf(MSG_DEBUG, "nl80211: Remove duplicated scan result "
                           "for " MACSTR, MAC2STR(r->bssid));
 
-               if ((r->flags & WPA_SCAN_ASSOCIATED) &&
-                   !(res->res[i]->flags & WPA_SCAN_ASSOCIATED)) {
+               if (((r->flags & WPA_SCAN_ASSOCIATED) &&
+                    !(res->res[i]->flags & WPA_SCAN_ASSOCIATED)) ||
+                   r->age < res->res[i]->age) {
                        os_free(res->res[i]);
                        res->res[i] = r;
                } else