OCE: Add RSSI based association rejection support (STA)

An AP might refuse to connect a STA if it has a low RSSI. In such case,
the AP informs the STA with the desired RSSI delta and a retry timeout.
Any subsequent association attempt with that AP (BSS) should be avoided,
unless the RSSI level improved by the desired delta or the timeout has
expired.

Defined in Wi-Fi Alliance Optimized Connectivity Experience technical
specification v1.0, section 3.14 (RSSI-based association rejection
information).

Signed-off-by: Beni Lev <beni.lev@intel.com>

src/common/ieee802_11_common.c

@@ -1538,6 +1538,24 @@ const u8 * get_ie_ext(const u8 *ies, size_t len, u8 ext)
 }
 
 
+const u8 * get_vendor_ie(const u8 *ies, size_t len, u32 vendor_type)
+{
+	const u8 *pos = ies, *end = ies + len;
+
+	while (end - pos > 1) {
+		if (2 + pos[1] > end - pos)
+			break;
+
+		if (pos[0] == WLAN_EID_VENDOR_SPECIFIC && pos[1] >= 4 &&
+		    vendor_type == WPA_GET_BE32(&pos[2]))
+			return pos;
+		pos += 2 + pos[1];
+	}
+
+	return NULL;
+}
+
+
 size_t mbo_add_ie(u8 *buf, size_t len, const u8 *attr, size_t attr_len)
 {
 	/*

src/common/ieee802_11_common.h

@@ -193,6 +193,7 @@ extern size_t global_op_class_size;
 
 const u8 * get_ie(const u8 *ies, size_t len, u8 eid);
 const u8 * get_ie_ext(const u8 *ies, size_t len, u8 ext);
+const u8 * get_vendor_ie(const u8 *ies, size_t len, u32 vendor_type);
 
 size_t mbo_add_ie(u8 *buf, size_t len, const u8 *attr, size_t attr_len);
 

wpa_supplicant/ctrl_iface.c

@@ -7959,6 +7959,8 @@ static void wpa_supplicant_ctrl_iface_flush(struct wpa_supplicant *wpa_s)
 	wpa_s->ric_ies = NULL;
 
 	wpa_supplicant_update_channel_list(wpa_s, NULL);
+
+	free_bss_tmp_disallowed(wpa_s);
 }
 
 

wpa_supplicant/events.c

@@ -1338,10 +1338,10 @@ struct wpa_ssid * wpa_scan_res_match(struct wpa_supplicant *wpa_s,
 			continue;
 		}
 
-		if (wpa_is_bss_tmp_disallowed(wpa_s, bss->bssid)) {
+		if (wpa_is_bss_tmp_disallowed(wpa_s, bss)) {
 			if (debug_print)
 				wpa_dbg(wpa_s, MSG_DEBUG,
-					"   skip - MBO retry delay has not passed yet");
+					"   skip - AP temporarily disallowed");
 			continue;
 		}
 #ifdef CONFIG_TESTING_OPTIONS
@@ -3060,7 +3060,7 @@ static void wpa_supplicant_event_disassoc_finish(struct wpa_supplicant *wpa_s,
 	    !disallowed_ssid(wpa_s, fast_reconnect->ssid,
 			     fast_reconnect->ssid_len) &&
 	    !wpas_temp_disabled(wpa_s, fast_reconnect_ssid) &&
-	    !wpa_is_bss_tmp_disallowed(wpa_s, fast_reconnect->bssid)) {
+	    !wpa_is_bss_tmp_disallowed(wpa_s, fast_reconnect)) {
 #ifndef CONFIG_NO_SCAN_PROCESSING
 		wpa_dbg(wpa_s, MSG_DEBUG, "Try to reconnect to the same BSS");
 		if (wpa_supplicant_connect(wpa_s, fast_reconnect,
@@ -4037,6 +4037,32 @@ static void wpas_event_assoc_reject(struct wpa_supplicant *wpa_s,
 	}
 #endif /* CONFIG_OWE */
 
+#ifdef CONFIG_MBO
+	if (data->assoc_reject.status_code ==
+	    WLAN_STATUS_DENIED_POOR_CHANNEL_CONDITIONS &&
+	    wpa_s->current_bss && data->assoc_reject.bssid &&
+	    data->assoc_reject.resp_ies) {
+		const u8 *rssi_rej;
+
+		rssi_rej = mbo_get_attr_from_ies(
+			data->assoc_reject.resp_ies,
+			data->assoc_reject.resp_ies_len,
+			OCE_ATTR_ID_RSSI_BASED_ASSOC_REJECT);
+		if (rssi_rej && rssi_rej[1] == 2) {
+			wpa_printf(MSG_DEBUG,
+				   "OCE: RSSI-based association rejection from "
+				   MACSTR " (Delta RSSI: %u, Retry Delay: %u)",
+				   MAC2STR(data->assoc_reject.bssid),
+				   rssi_rej[2], rssi_rej[3]);
+			wpa_bss_tmp_disallow(wpa_s,
+					     data->assoc_reject.bssid,
+					     rssi_rej[3],
+					     rssi_rej[2] +
+					     wpa_s->current_bss->level);
+		}
+	}
+#endif /* CONFIG_MBO */
+
 	if (wpa_s->drv_flags & WPA_DRIVER_FLAGS_SME) {
 		sme_event_assoc_reject(wpa_s, data);
 		return;

wpa_supplicant/mbo.c

@@ -51,6 +51,19 @@ const u8 * mbo_attr_from_mbo_ie(const u8 *mbo_ie, enum mbo_attr_id attr)
 }
 
 
+const u8 * mbo_get_attr_from_ies(const u8 *ies, size_t ies_len,
+				 enum mbo_attr_id attr)
+{
+	const u8 *mbo_ie;
+
+	mbo_ie = get_vendor_ie(ies, ies_len, MBO_IE_VENDOR_TYPE);
+	if (!mbo_ie)
+		return NULL;
+
+	return mbo_attr_from_mbo_ie(mbo_ie, attr);
+}
+
+
 const u8 * wpas_mbo_get_bss_attr(struct wpa_bss *bss, enum mbo_attr_id attr)
 {
 	const u8 *mbo, *end;
@@ -501,7 +514,7 @@ void wpas_mbo_ie_trans_req(struct wpa_supplicant *wpa_s, const u8 *mbo_ie,
 
 	if (disallowed_sec && wpa_s->current_bss)
 		wpa_bss_tmp_disallow(wpa_s, wpa_s->current_bss->bssid,
-				     disallowed_sec);
+				     disallowed_sec, 0);
 
 	return;
 fail:

wpa_supplicant/wnm_sta.c

@@ -770,7 +770,7 @@ compare_scan_neighbor_results(struct wpa_supplicant *wpa_s, os_time_t age_secs,
 			continue;
 		}
 
-		if (wpa_is_bss_tmp_disallowed(wpa_s, target->bssid)) {
+		if (wpa_is_bss_tmp_disallowed(wpa_s, target)) {
 			wpa_printf(MSG_DEBUG,
 				   "MBO: Candidate BSS " MACSTR
 				   " retry delay is not over yet",

wpa_supplicant/wpa_supplicant.c

@@ -444,7 +444,7 @@ void free_hw_features(struct wpa_supplicant *wpa_s)
 }
 
 
-static void free_bss_tmp_disallowed(struct wpa_supplicant *wpa_s)
+void free_bss_tmp_disallowed(struct wpa_supplicant *wpa_s)
 {
 	struct wpa_bss_tmp_disallowed *bss, *prev;
 
@@ -7264,16 +7264,14 @@ static void wpa_bss_tmp_disallow_timeout(void *eloop_ctx, void *timeout_ctx)
 
 
 void wpa_bss_tmp_disallow(struct wpa_supplicant *wpa_s, const u8 *bssid,
-			  unsigned int sec)
+			  unsigned int sec, int rssi_threshold)
 {
 	struct wpa_bss_tmp_disallowed *bss;
 
 	bss = wpas_get_disallowed_bss(wpa_s, bssid);
 	if (bss) {
 		eloop_cancel_timeout(wpa_bss_tmp_disallow_timeout, wpa_s, bss);
-		eloop_register_timeout(sec, 0, wpa_bss_tmp_disallow_timeout,
+		goto finish;
-				       wpa_s, bss);
-		return;
 	}
 
 	bss = os_malloc(sizeof(*bss));
@@ -7286,23 +7284,31 @@ void wpa_bss_tmp_disallow(struct wpa_supplicant *wpa_s, const u8 *bssid,
 	os_memcpy(bss->bssid, bssid, ETH_ALEN);
 	dl_list_add(&wpa_s->bss_tmp_disallowed, &bss->list);
 	wpa_set_driver_tmp_disallow_list(wpa_s);
+
+finish:
+	bss->rssi_threshold = rssi_threshold;
 	eloop_register_timeout(sec, 0, wpa_bss_tmp_disallow_timeout,
 			       wpa_s, bss);
 }
 
 
-int wpa_is_bss_tmp_disallowed(struct wpa_supplicant *wpa_s, const u8 *bssid)
+int wpa_is_bss_tmp_disallowed(struct wpa_supplicant *wpa_s,
+			      struct wpa_bss *bss)
 {
-	struct wpa_bss_tmp_disallowed *bss = NULL, *tmp, *prev;
+	struct wpa_bss_tmp_disallowed *disallowed = NULL, *tmp, *prev;
 
 	dl_list_for_each_safe(tmp, prev, &wpa_s->bss_tmp_disallowed,
 			 struct wpa_bss_tmp_disallowed, list) {
-		if (os_memcmp(bssid, tmp->bssid, ETH_ALEN) == 0) {
+		if (os_memcmp(bss->bssid, tmp->bssid, ETH_ALEN) == 0) {
-			bss = tmp;
+			disallowed = tmp;
 			break;
 		}
 	}
-	if (!bss)
+	if (!disallowed)
+		return 0;
+
+	if (disallowed->rssi_threshold != 0 &&
+	    bss->level > disallowed->rssi_threshold)
 		return 0;
 
 	return 1;

wpa_supplicant/wpa_supplicant_i.h

@@ -451,6 +451,7 @@ struct icon_entry {
 struct wpa_bss_tmp_disallowed {
 	struct dl_list list;
 	u8 bssid[ETH_ALEN];
+	int rssi_threshold;
 };
 
 struct beacon_rep_data {
@@ -1371,6 +1372,8 @@ int wpas_mbo_ie(struct wpa_supplicant *wpa_s, u8 *buf, size_t len,
 		int add_oce_capa);
 const u8 * mbo_attr_from_mbo_ie(const u8 *mbo_ie, enum mbo_attr_id attr);
 const u8 * wpas_mbo_get_bss_attr(struct wpa_bss *bss, enum mbo_attr_id attr);
+const u8 * mbo_get_attr_from_ies(const u8 *ies, size_t ies_len,
+				 enum mbo_attr_id attr);
 int wpas_mbo_update_non_pref_chan(struct wpa_supplicant *wpa_s,
 				  const char *non_pref_chan);
 void wpas_mbo_scan_ie(struct wpa_supplicant *wpa_s, struct wpabuf *ie);
@@ -1481,8 +1484,10 @@ struct hostapd_hw_modes * get_mode(struct hostapd_hw_modes *modes,
 				   u16 num_modes, enum hostapd_hw_mode mode);
 
 void wpa_bss_tmp_disallow(struct wpa_supplicant *wpa_s, const u8 *bssid,
-			  unsigned int sec);
+			  unsigned int sec, int rssi_threshold);
-int wpa_is_bss_tmp_disallowed(struct wpa_supplicant *wpa_s, const u8 *bssid);
+int wpa_is_bss_tmp_disallowed(struct wpa_supplicant *wpa_s,
+			      struct wpa_bss *bss);
+void free_bss_tmp_disallowed(struct wpa_supplicant *wpa_s);
 
 struct wpa_ssid * wpa_scan_res_match(struct wpa_supplicant *wpa_s,
 				     int i, struct wpa_bss *bss,