net: mgmt: Support for forced Passive scan

Default scan mode is Active. User can force the scan mode to passive
through Kconfig option or using 'passive' option from shell.
Using either of this option will override regulatory settings and
forces all scan channels to be passive only.

Signed-off-by: Ajay Parida <[email protected]>

Author: ajayparida

drivers/wifi/esp32/src/esp_wifi_drv.c

@@ -388,7 +388,9 @@ static int esp32_wifi_connect(const struct device *dev,
 	return 0;
 }
 
-static int esp32_wifi_scan(const struct device *dev, scan_result_cb_t cb)
+static int esp32_wifi_scan(const struct device *dev,
+			   struct wifi_scan_params *params,
+			   scan_result_cb_t cb)
 {
 	struct esp32_wifi_runtime *data = dev->data;
 	int ret = 0;
@@ -402,6 +404,11 @@ static int esp32_wifi_scan(const struct device *dev, scan_result_cb_t cb)
 
 	wifi_scan_config_t scan_config = { 0 };
 
+	if (params) {
+		/* The enum values are same, so, no conversion needed */
+		scan_config->scan_type = params->scan_type;
+	}
+
 	ret = esp_wifi_set_mode(ESP32_WIFI_MODE_STA);
 	ret |= esp_wifi_scan_start(&scan_config, false);
 

drivers/wifi/esp_at/esp.c

@@ -899,10 +899,14 @@ static void esp_mgmt_scan_work(struct k_work *work)
 	dev->scan_cb = NULL;
 }
 
-static int esp_mgmt_scan(const struct device *dev, scan_result_cb_t cb)
+static int esp_mgmt_scan(const struct device *dev,
+			 struct wifi_scan_params *params,
+			 scan_result_cb_t cb)
 {
 	struct esp_data *data = dev->data;
 
+	ARG_UNUSED(params);
+
 	if (data->scan_cb != NULL) {
 		return -EINPROGRESS;
 	}

drivers/wifi/eswifi/eswifi_core.c

@@ -520,10 +520,14 @@ int eswifi_mgmt_iface_status(const struct device *dev,
 	return 0;
 }
 
-static int eswifi_mgmt_scan(const struct device *dev, scan_result_cb_t cb)
+static int eswifi_mgmt_scan(const struct device *dev,
+			    struct wifi_scan_params *params,
+			    scan_result_cb_t cb)
 {
 	struct eswifi_dev *eswifi = dev->data;
 
+	ARG_UNUSED(params);
+
 	LOG_DBG("");
 
 	eswifi_lock(eswifi);

drivers/wifi/simplelink/simplelink.c

@@ -136,11 +136,15 @@ static void simplelink_scan_work_handler(struct k_work *work)
 	}
 }
 
-static int simplelink_mgmt_scan(const struct device *dev, scan_result_cb_t cb)
+static int simplelink_mgmt_scan(const struct device *dev,
+				struct wifi_scan_params *params,
+				scan_result_cb_t cb)
 {
 	int err;
 	int status;
 
+	ARG_UNUSED(params);
+
 	/* Cancel any previous scan processing in progress: */
 	k_work_cancel_delayable(&simplelink_data.work);
 

drivers/wifi/winc1500/wifi_winc1500.c

@@ -976,8 +976,12 @@ static void winc1500_thread(void)
 	}
 }
 
-static int winc1500_mgmt_scan(const struct device *dev, scan_result_cb_t cb)
+static int winc1500_mgmt_scan(const struct device *dev,
+			      struct wifi_scan_params *params,
+			      scan_result_cb_t cb)
 {
+	ARG_UNUSED(params);
+
 	if (w1500_data.scan_cb) {
 		return -EALREADY;
 	}

include/zephyr/net/wifi.h

@@ -264,6 +264,11 @@ static inline const char *wifi_link_mode_txt(enum wifi_link_mode link_mode)
 	}
 }
 
+enum wifi_scan_type {
+	WIFI_SCAN_TYPE_ACTIVE = 0,
+	WIFI_SCAN_TYPE_PASSIVE,
+};
+
 enum wifi_ps {
 	WIFI_PS_DISABLED = 0,
 	WIFI_PS_ENABLED,

include/zephyr/net/wifi_mgmt.h

@@ -143,6 +143,16 @@ enum net_event_wifi_cmd {
 
 #define NET_EVENT_WIFI_DISCONNECT_COMPLETE			\
 	(_NET_WIFI_EVENT | NET_EVENT_WIFI_CMD_DISCONNECT_COMPLETE)
+
+struct wifi_scan_params {
+	/* The scan_type is only a hint to the underlying Wi-Fi chip for the
+	 * preferred mode of scan. The actual mode of scan can depend on factors
+	 * such as the Wi-Fi chip implementation support, regulatory domain
+	 * restrictions etc.
+	 */
+	enum wifi_scan_type scan_type;
+};
+
 /* Each result is provided to the net_mgmt_event_callback
  * via its info attribute (see net_mgmt.h)
  */
@@ -321,7 +331,9 @@ struct net_wifi_mgmt_offload {
 	 * result by the driver. The wifi mgmt part will take care of
 	 * raising the necessary event etc...
 	 */
-	int (*scan)(const struct device *dev, scan_result_cb_t cb);
+	int (*scan)(const struct device *dev,
+		    struct wifi_scan_params *params,
+		    scan_result_cb_t cb);
 	int (*connect)(const struct device *dev,
 		       struct wifi_connect_req_params *params);
 	int (*disconnect)(const struct device *dev);

subsys/net/l2/wifi/Kconfig

@@ -38,3 +38,11 @@ config WIFI_MGMT_TWT_CHECK_IP
 	  being unreachable (IP Level) or unable to receive down link traffic
 	  even when it is awake intervals. Rejecting TWT setup till Wi-Fi
 	  interface has a valid IP address might be desirable in most scenarios.
+
+config WIFI_MGMT_FORCED_PASSIVE_SCAN
+	bool "Force Passive scan"
+	help
+	  Force passive scan (typically used to reduce power consumption),
+	  the scan type is always sent as passive.
+	  This doesn't guarantee that passive scan will be used, it depends
+	  on the underlying chip implementation to support and honour scan type.

subsys/net/l2/wifi/wifi_mgmt.c

@@ -84,12 +84,19 @@ static int wifi_scan(uint32_t mgmt_request, struct net_if *iface,
 	const struct device *dev = net_if_get_device(iface);
 	struct net_wifi_mgmt_offload *off_api =
 		(struct net_wifi_mgmt_offload *) dev->api;
+	struct wifi_scan_params *params = data;
 
 	if (off_api == NULL || off_api->scan == NULL) {
 		return -ENOTSUP;
 	}
 
-	return off_api->scan(dev, scan_result_cb);
+	if (data && (len == sizeof(*params))) {
+#ifdef CONFIG_WIFI_MGMT_FORCED_PASSIVE_SCAN
+		params->scan_type = WIFI_SCAN_TYPE_PASSIVE;
+#endif
+	}
+
+	return off_api->scan(dev, params, scan_result_cb);
 }
 
 NET_MGMT_REGISTER_REQUEST_HANDLER(NET_REQUEST_WIFI_SCAN, wifi_scan);

subsys/net/l2/wifi/wifi_shell.c

@@ -447,10 +447,29 @@ static int cmd_wifi_disconnect(const struct shell *sh, size_t argc,
 static int cmd_wifi_scan(const struct shell *sh, size_t argc, char *argv[])
 {
 	struct net_if *iface = net_if_get_first_wifi();
+	struct wifi_scan_params params = { 0 };
 
 	context.sh = sh;
 
-	if (net_mgmt(NET_REQUEST_WIFI_SCAN, iface, NULL, 0)) {
+	if (argc > 2) {
+		shell_fprintf(sh, SHELL_WARNING, "Invalid number of arguments\n");
+		return -ENOEXEC;
+	}
+
+	if (argc == 2) {
+		if (!strcmp(argv[1], "passive")) {
+			params.scan_type = WIFI_SCAN_TYPE_PASSIVE;
+		} else if (!strcmp(argv[1], "active")) {
+			params.scan_type = WIFI_SCAN_TYPE_ACTIVE;
+		} else {
+			shell_fprintf(sh, SHELL_WARNING, "Invalid argument\n");
+			shell_fprintf(sh, SHELL_INFO,
+				      "Valid argument : <active> / <passive>\n");
+			return -ENOEXEC;
+		}
+	}
+
+	if (net_mgmt(NET_REQUEST_WIFI_SCAN, iface, &params, sizeof(params))) {
 		shell_fprintf(sh, SHELL_WARNING, "Scan request failed\n");
 
 		return -ENOEXEC;
@@ -1114,7 +1133,10 @@ SHELL_STATIC_SUBCMD_SET_CREATE(wifi_commands,
 		      cmd_wifi_ps_mode,
 		      2,
 		      0),
-	SHELL_CMD(scan, NULL, "Scan for Wi-Fi APs", cmd_wifi_scan),
+	SHELL_CMD(scan, NULL,
+		  "Scan for Wi-Fi APs\n"
+		  "<scan type (optional): <active> : <passive>>\n",
+		  cmd_wifi_scan),
 	SHELL_CMD(statistics, NULL, "Wi-Fi interface statistics", cmd_wifi_stats),
 	SHELL_CMD(status, NULL, "Status of the Wi-Fi interface", cmd_wifi_status),
 	SHELL_CMD(twt, &wifi_twt_ops, "Manage TWT flows", NULL),