WNM: Ignore WNM-Sleep Mode Response without pending request

Commit 03ed0a52393710be6bdae657d1b36efa146520e5 ('WNM: Ignore WNM-Sleep
Mode Response if WNM-Sleep Mode has not been used') started ignoring the
response when no WNM-Sleep Mode Request had been used during the
association. This can be made tighter by clearing the used flag when
successfully processing a response. This adds an additional layer of
protection against unexpected retransmissions of the response frame.

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

wpa_supplicant/wnm_sta.c

@@ -260,7 +260,7 @@ static void ieee802_11_rx_wnmsleep_resp(struct wpa_supplicant *wpa_s,
 
 	if (!wpa_s->wnmsleep_used) {
 		wpa_printf(MSG_DEBUG,
-			   "WNM: Ignore WNM-Sleep Mode Response frame since WNM-Sleep Mode has not been used in this association");
+			   "WNM: Ignore WNM-Sleep Mode Response frame since WNM-Sleep Mode operation has not been requested");
 		return;
 	}
 
@@ -299,6 +299,8 @@ static void ieee802_11_rx_wnmsleep_resp(struct wpa_supplicant *wpa_s,
 		return;
 	}
 
+	wpa_s->wnmsleep_used = 0;
+
 	if (wnmsleep_ie->status == WNM_STATUS_SLEEP_ACCEPT ||
 	    wnmsleep_ie->status == WNM_STATUS_SLEEP_EXIT_ACCEPT_GTK_UPDATE) {
 		wpa_printf(MSG_DEBUG, "Successfully recv WNM-Sleep Response "