hostap: bgscan support in Zephyr

include/zephyr/net/wifi_mgmt.h

@@ -137,6 +137,8 @@ enum net_request_wifi_cmd {
 	NET_REQUEST_WIFI_CMD_AP_WPS_CONFIG,
 	/** Configure BSS maximum idle period */
 	NET_REQUEST_WIFI_CMD_BSS_MAX_IDLE_PERIOD,
+	/** Configure background scanning */
+	NET_REQUEST_WIFI_CMD_BGSCAN,
 	/** @cond INTERNAL_HIDDEN */
 	NET_REQUEST_WIFI_CMD_MAX
 	/** @endcond */
@@ -332,6 +334,11 @@ NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_WIFI_NEIGHBOR_REP_COMPLETE);
 
 NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_WIFI_BSS_MAX_IDLE_PERIOD);
 
+#define NET_REQUEST_WIFI_BGSCAN					\
+	(NET_WIFI_BASE | NET_REQUEST_WIFI_CMD_BGSCAN)
+
+NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_WIFI_BGSCAN);
+
 /** @cond INTERNAL_HIDDEN */
 
 enum {
@@ -1393,6 +1400,32 @@ enum wifi_sap_iface_state {
 	WIFI_SAP_IFACE_ENABLED
 };
 
+#if defined(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN) || defined(__DOXYGEN__)
+/** @brief Wi-Fi background scan implementation */
+enum wifi_bgscan_type {
+	/** None, background scan is disabled */
+	WIFI_BGSCAN_NONE = 0,
+	/** Simple, periodic scan based on signal strength */
+	WIFI_BGSCAN_SIMPLE,
+	/** Learn channels used by the network (experimental) */
+	WIFI_BGSCAN_LEARN,
+};
+
+/** @brief Wi-Fi background scan parameters */
+struct wifi_bgscan_params {
+	/** The type of background scanning */
+	enum wifi_bgscan_type type;
+	/** Short scan interval in seconds */
+	uint16_t short_interval;
+	/** Long scan interval in seconds */
+	uint16_t long_interval;
+	/** Signal strength threshold in dBm */
+	int8_t rssi_threshold;
+	/** Number of BSS Transition Management (BTM) queries */
+	uint16_t btm_queries;
+};
+#endif
+
 /* Extended Capabilities */
 enum wifi_ext_capab {
 	WIFI_EXT_CAPAB_20_40_COEX = 0,
@@ -1732,6 +1765,16 @@ struct wifi_mgmt_ops {
 	 */
 	int (*set_bss_max_idle_period)(const struct device *dev,
 			unsigned short bss_max_idle_period);
+#if defined(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN) || defined(__DOXYGEN__)
+	/** Configure background scanning
+	 *
+	 * @param dev Pointer to the device structure for the driver instance.
+	 * @param params Background scanning configuration parameters
+	 *
+	 * @return 0 if ok, < 0 if error
+	 */
+	int (*set_bgscan)(const struct device *dev, struct wifi_bgscan_params *params);
+#endif
 };
 
 /** Wi-Fi management offload API */

modules/hostap/CMakeLists.txt

@@ -78,6 +78,16 @@ zephyr_library_compile_definitions_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_WNM
   CONFIG_WNM
 )
 
+zephyr_library_compile_definitions_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN
+  CONFIG_BGSCAN
+)
+zephyr_library_compile_definitions_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_SIMPLE
+  CONFIG_BGSCAN_SIMPLE
+)
+zephyr_library_compile_definitions_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_LEARN
+  CONFIG_BGSCAN_LEARN
+)
+
 zephyr_library_include_directories(
   ${CMAKE_CURRENT_SOURCE_DIR}/src
   ${HOSTAP_BASE}/
@@ -156,6 +166,16 @@ zephyr_library_sources_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_WNM
   ${WIFI_NM_WPA_SUPPLICANT_BASE}/wnm_sta.c
 )
 
+zephyr_library_sources_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN
+  ${WIFI_NM_WPA_SUPPLICANT_BASE}/bgscan.c
+)
+zephyr_library_sources_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_SIMPLE
+  ${WIFI_NM_WPA_SUPPLICANT_BASE}/bgscan_simple.c
+)
+zephyr_library_sources_ifdef(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_LEARN
+  ${WIFI_NM_WPA_SUPPLICANT_BASE}/bgscan_learn.c
+)
+
 zephyr_library_sources_ifdef(CONFIG_WPA_CLI
   src/wpa_cli.c
 )

modules/hostap/Kconfig

@@ -455,6 +455,27 @@ config WIFI_NM_WPA_SUPPLICANT_SKIP_DHCP_ON_ROAMING
 	  needs to get new IP address after roaming to new AP. Disable this to keep
 	  DHCP after roaming.
 
+config WIFI_NM_WPA_SUPPLICANT_BGSCAN
+	bool "Background scanning (for legacy roaming), recommended if 802.11r is not supported"
+	depends on WIFI_NM_WPA_SUPPLICANT_WNM
+	depends on !WIFI_NM_WPA_SUPPLICANT_ROAMING
+
+if WIFI_NM_WPA_SUPPLICANT_BGSCAN
+
+config WIFI_NM_WPA_SUPPLICANT_BGSCAN_SIMPLE
+	bool "Simple background scanning"
+	default y
+	help
+	  Periodic background scans based on signal strength.
+
+config WIFI_NM_WPA_SUPPLICANT_BGSCAN_LEARN
+	bool "Learning"
+	help
+	  Learn channels used by the network and try to avoid
+	  background scans on other channels (experimental).
+
+endif # WIFI_NM_WPA_SUPPLICANT_BGSCAN
+
 # Create hidden config options that are used in hostap. This way we do not need
 # to mark them as allowed for CI checks, and also someone else cannot use the
 # same name options.
@@ -486,6 +507,15 @@ config NO_RANDOM_POOL
 config WNM
 	bool
 
+config BGSCAN
+	bool
+
+config BGSCAN_SIMPLE
+	bool
+
+config BGSCAN_LEARN
+	bool
+
 config NO_WPA
 	bool
 	default y if WIFI_NM_WPA_SUPPLICANT_CRYPTO_NONE

modules/hostap/src/supp_api.c

@@ -1907,6 +1907,71 @@ int supplicant_set_bss_max_idle_period(const struct device *dev,
 	return wifi_mgmt_api->set_bss_max_idle_period(dev, bss_max_idle_period);
 }
 
+#ifdef CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN
+int supplicant_set_bgscan(const struct device *dev, struct wifi_bgscan_params *params)
+{
+	struct wpa_supplicant *wpa_s;
+	struct wpa_ssid *ssid;
+	int ret = -1;
+
+	k_mutex_lock(&wpa_supplicant_mutex, K_FOREVER);
+
+	wpa_s = get_wpa_s_handle(dev);
+	if (wpa_s == NULL) {
+		wpa_printf(MSG_ERROR, "Interface %s not found", dev->name);
+		goto out;
+	}
+
+	ssid = wpa_s->current_ssid;
+	if (ssid == NULL) {
+		wpa_printf(MSG_ERROR, "SSID for %s not found", dev->name);
+		goto out;
+	}
+
+	switch (params->type) {
+	case WIFI_BGSCAN_SIMPLE:
+		if (!IS_ENABLED(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_SIMPLE)) {
+			wpa_printf(MSG_ERROR, "Invalid bgscan type, enable "
+					      "CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_SIMPLE");
+			ret = -ENOTSUP;
+			goto out;
+		}
+		if (!wpa_cli_cmd_v("set_network %d bgscan \"simple:%d:%d:%d:%d\"", ssid->id,
+				   params->short_interval, params->rssi_threshold,
+				   params->long_interval, params->btm_queries)) {
+			goto out;
+		}
+		break;
+	case WIFI_BGSCAN_LEARN:
+		if (!IS_ENABLED(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_LEARN)) {
+			wpa_printf(MSG_ERROR, "Invalid bgscan type, enable "
+					      "CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN_LEARN");
+			ret = -ENOTSUP;
+			goto out;
+		}
+		if (!wpa_cli_cmd_v("set_network %d bgscan \"learn:%d:%d:%d\"", ssid->id,
+				   params->short_interval, params->rssi_threshold,
+				   params->long_interval)) {
+			goto out;
+		}
+		break;
+	case WIFI_BGSCAN_NONE:
+	default:
+		if (!wpa_cli_cmd_v("set_network %d bgscan \"\"", ssid->id)) {
+			goto out;
+		}
+		break;
+	}
+
+	ret = 0;
+
+out:
+	k_mutex_unlock(&wpa_supplicant_mutex);
+
+	return ret;
+}
+#endif
+
 #ifdef CONFIG_WIFI_NM_WPA_SUPPLICANT_WNM
 int supplicant_btm_query(const struct device *dev, uint8_t reason)
 {

modules/hostap/src/supp_api.h

@@ -321,6 +321,17 @@ int supplicant_wps_config(const struct device *dev, struct wifi_wps_config_param
  */
 int supplicant_set_bss_max_idle_period(const struct device *dev,
 				       unsigned short bss_max_idle_period);
+
+#if defined(CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN) || defined(__DOXYGEN__)
+/** @ Set Wi-Fi background scanning parameters
+ *
+ * @param dev Wi-Fi interface handle to use
+ * @param params bgscan parameters
+ * @return 0 for OK; -1 for ERROR
+ */
+int supplicant_set_bgscan(const struct device *dev, struct wifi_bgscan_params *params);
+#endif
+
 #ifdef CONFIG_AP
 int set_ap_bandwidth(const struct device *dev, enum wifi_frequency_bandwidths bandwidth);
 

modules/hostap/src/supp_main.c

@@ -85,6 +85,9 @@ static const struct wifi_mgmt_ops mgmt_ops = {
 	.get_conn_params = supplicant_get_wifi_conn_params,
 	.wps_config = supplicant_wps_config,
 	.set_bss_max_idle_period = supplicant_set_bss_max_idle_period,
+#ifdef CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN
+	.set_bgscan = supplicant_set_bgscan,
+#endif /* CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN */
 #ifdef CONFIG_AP
 	.ap_enable = supplicant_ap_enable,
 	.ap_disable = supplicant_ap_disable,

subsys/net/l2/wifi/wifi_mgmt.c

@@ -1450,6 +1450,31 @@ static int wifi_set_bss_max_idle_period(uint64_t mgmt_request, struct net_if *if
 NET_MGMT_REGISTER_REQUEST_HANDLER(NET_REQUEST_WIFI_BSS_MAX_IDLE_PERIOD,
 				  wifi_set_bss_max_idle_period);
 
+#ifdef CONFIG_WIFI_NM_WPA_SUPPLICANT_BGSCAN
+static int wifi_set_bgscan(uint64_t mgmt_request, struct net_if *iface, void *data, size_t len)
+{
+	const struct device *dev = net_if_get_device(iface);
+	const struct wifi_mgmt_ops *const wifi_mgmt_api = get_wifi_api(iface);
+	struct wifi_bgscan_params *params = data;
+
+	if (wifi_mgmt_api == NULL || wifi_mgmt_api->set_bgscan == NULL) {
+		return -ENOTSUP;
+	}
+
+	if (!net_if_is_admin_up(iface)) {
+		return -ENETDOWN;
+	}
+
+	if (data == NULL || len != sizeof(*params)) {
+		return -EINVAL;
+	}
+
+	return wifi_mgmt_api->set_bgscan(dev, params);
+}
+
+NET_MGMT_REGISTER_REQUEST_HANDLER(NET_REQUEST_WIFI_BGSCAN, wifi_set_bgscan);
+#endif
+
 #ifdef CONFIG_WIFI_MGMT_RAW_SCAN_RESULTS
 void wifi_mgmt_raise_raw_scan_result_event(struct net_if *iface,
 					   struct wifi_raw_scan_result *raw_scan_result)