TDLS: Implement low-ack event for lost TDLS peers

Disable the direct connection when a TDLS peer stops responding
to packets, as indicated by the "LOW ACK" event coming from a driver.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Cc: Kalyan C Gaddam <chakkal@iit.edu>

src/rsn_supp/tdls.c

@@ -751,6 +751,22 @@ int wpa_tdls_teardown_link(struct wpa_sm *sm, const u8 *addr, u16 reason_code)
 }
 
 
+void wpa_tdls_disable_link(struct wpa_sm *sm, const u8 *addr)
+{
+	struct wpa_tdls_peer *peer;
+
+	for (peer = sm->tdls; peer; peer = peer->next) {
+		if (os_memcmp(peer->addr, addr, ETH_ALEN) == 0)
+			break;
+	}
+
+	if (peer) {
+		wpa_sm_tdls_oper(sm, TDLS_DISABLE_LINK, addr);
+		wpa_tdls_peer_free(sm, peer);
+	}
+}
+
+
 static int wpa_tdls_recv_teardown(struct wpa_sm *sm, const u8 *src_addr,
 				  const u8 *buf, size_t len)
 {

src/rsn_supp/wpa.h

@@ -366,5 +366,6 @@ int wpa_tdls_send_discovery_request(struct wpa_sm *sm, const u8 *addr);
 int wpa_tdls_init(struct wpa_sm *sm);
 void wpa_tdls_deinit(struct wpa_sm *sm);
 void wpa_tdls_enable(struct wpa_sm *sm, int enabled);
+void wpa_tdls_disable_link(struct wpa_sm *sm, const u8 *addr);
 
 #endif /* WPA_H */

wpa_supplicant/events.c

@@ -2410,6 +2410,10 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 			hostapd_event_sta_low_ack(wpa_s->ap_iface->bss[0],
 						  data->low_ack.addr);
 #endif /* CONFIG_AP */
+#ifdef CONFIG_TDLS
+		if (data)
+			wpa_tdls_disable_link(wpa_s->wpa, data->low_ack.addr);
+#endif /* CONFIG_TDLS */
 		break;
 	case EVENT_IBSS_PEER_LOST:
 #ifdef CONFIG_IBSS_RSN