Add BSSID filter for testing purposes

wpa_supplicant can now be configured to filter out scan results based
on a BSSID filter. Space-separated set of allowed BSSIDs can be set
with wpa_cli set bssid_filter command. Filtering mechanism can be
disabled by setting this variable to an empty list. When set, only
the BSSes that have a matching entry in this list will be accepted
from scan results.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

wpa_supplicant/bss.c

@@ -61,6 +61,8 @@ struct wpa_bss * wpa_bss_get(struct wpa_supplicant *wpa_s, const u8 *bssid,
 			     const u8 *ssid, size_t ssid_len)
 {
 	struct wpa_bss *bss;
+	if (!wpa_supplicant_filter_bssid_match(wpa_s, bssid))
+		return NULL;
 	dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
 		if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0 &&
 		    bss->ssid_len == ssid_len &&
@@ -526,6 +528,8 @@ struct wpa_bss * wpa_bss_get_bssid(struct wpa_supplicant *wpa_s,
 				   const u8 *bssid)
 {
 	struct wpa_bss *bss;
+	if (!wpa_supplicant_filter_bssid_match(wpa_s, bssid))
+		return NULL;
 	dl_list_for_each_reverse(bss, &wpa_s->bss, struct wpa_bss, list) {
 		if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0)
 			return bss;

wpa_supplicant/ctrl_iface.c

@@ -114,6 +114,41 @@ static int pno_stop(struct wpa_supplicant *wpa_s)
 }
 
 
+static int set_bssid_filter(struct wpa_supplicant *wpa_s, char *val)
+{
+	char *pos;
+	u8 addr[ETH_ALEN], *filter = NULL, *n;
+	size_t count = 0;
+
+	pos = val;
+	while (pos) {
+		if (*pos == '\0')
+			break;
+		if (hwaddr_aton(pos, addr))
+			return -1;
+		n = os_realloc(filter, (count + 1) * ETH_ALEN);
+		if (n == NULL) {
+			os_free(filter);
+			return -1;
+		}
+		filter = n;
+		os_memcpy(filter + count * ETH_ALEN, addr, ETH_ALEN);
+		count++;
+
+		pos = os_strchr(pos, ' ');
+		if (pos)
+			pos++;
+	}
+
+	wpa_hexdump(MSG_DEBUG, "bssid_filter", filter, count * ETH_ALEN);
+	os_free(wpa_s->bssid_filter);
+	wpa_s->bssid_filter = filter;
+	wpa_s->bssid_filter_count = count;
+
+	return 0;
+}
+
+
 static int wpa_supplicant_ctrl_iface_set(struct wpa_supplicant *wpa_s,
 					 char *cmd)
 {
@@ -241,6 +276,8 @@ static int wpa_supplicant_ctrl_iface_set(struct wpa_supplicant *wpa_s,
 		}
 	} else if (os_strcasecmp(cmd, "ps") == 0) {
 		ret = wpa_drv_set_p2p_powersave(wpa_s, atoi(value), -1, -1);
+	} else if (os_strcasecmp(cmd, "bssid_filter") == 0) {
+		ret = set_bssid_filter(wpa_s, value);
 	} else {
 		value[-1] = '=';
 		ret = wpa_config_process_global(wpa_s->conf, cmd, -1);

wpa_supplicant/scan.c

@@ -1235,6 +1235,50 @@ static void dump_scan_res(struct wpa_scan_results *scan_res)
 }
 
 
+int wpa_supplicant_filter_bssid_match(struct wpa_supplicant *wpa_s,
+				      const u8 *bssid)
+{
+	size_t i;
+
+	if (wpa_s->bssid_filter == NULL)
+		return 1;
+
+	for (i = 0; i < wpa_s->bssid_filter_count; i++) {
+		if (os_memcmp(wpa_s->bssid_filter + i * ETH_ALEN, bssid,
+			      ETH_ALEN) == 0)
+			return 1;
+	}
+
+	return 0;
+}
+
+
+static void filter_scan_res(struct wpa_supplicant *wpa_s,
+			    struct wpa_scan_results *res)
+{
+	size_t i, j;
+
+	if (wpa_s->bssid_filter == NULL)
+		return;
+
+	for (i = 0, j = 0; i < res->num; i++) {
+		if (wpa_supplicant_filter_bssid_match(wpa_s,
+						      res->res[i]->bssid)) {
+			res->res[j++] = res->res[i];
+		} else {
+			os_free(res->res[i]);
+			res->res[i] = NULL;
+		}
+	}
+
+	if (res->num != j) {
+		wpa_printf(MSG_DEBUG, "Filtered out %d scan results",
+			   (int) (res->num - j));
+		res->num = j;
+	}
+}
+
+
 /**
  * wpa_supplicant_get_scan_results - Get scan results
  * @wpa_s: Pointer to wpa_supplicant data
@@ -1259,6 +1303,7 @@ wpa_supplicant_get_scan_results(struct wpa_supplicant *wpa_s,
 		wpa_dbg(wpa_s, MSG_DEBUG, "Failed to get scan results");
 		return NULL;
 	}
+	filter_scan_res(wpa_s, scan_res);
 
 #ifdef CONFIG_WPS
 	if (wpas_wps_in_progress(wpa_s)) {

wpa_supplicant/scan.h

@@ -32,5 +32,7 @@ struct wpabuf * wpa_scan_get_vendor_ie_multi(const struct wpa_scan_res *res,
 					     u32 vendor_type);
 struct wpabuf * wpa_scan_get_vendor_ie_multi_beacon(
 	const struct wpa_scan_res *res, u32 vendor_type);
+int wpa_supplicant_filter_bssid_match(struct wpa_supplicant *wpa_s,
+				      const u8 *bssid);
 
 #endif /* SCAN_H */

wpa_supplicant/wpa_supplicant.c

@@ -445,6 +445,9 @@ static void wpa_supplicant_cleanup(struct wpa_supplicant *wpa_s)
 	wpa_s->gas = NULL;
 
 	free_hw_features(wpa_s);
+
+	os_free(wpa_s->bssid_filter);
+	wpa_s->bssid_filter = NULL;
 }
 
 

wpa_supplicant/wpa_supplicant_i.h

@@ -280,6 +280,9 @@ struct wpa_supplicant {
 	void *drv_priv; /* private data used by driver_ops */
 	void *global_drv_priv;
 
+	u8 *bssid_filter;
+	size_t bssid_filter_count;
+
 	/* previous scan was wildcard when interleaving between
 	 * wildcard scans and specific SSID scan when max_ssids=1 */
 	int prev_scan_wildcard;