ZEP-55: Implemented WiFi.scan() functionality.

Author: bogdanarduino

libraries/WiFi/src/WiFi.cpp

@@ -2,6 +2,8 @@
 
 WiFiClass WiFi;
 
+WiFiClass *WiFiClass::instance = nullptr;
+
 String WiFiClass::firmwareVersion() {
 #if defined(ARDUINO_PORTENTA_C33)
 	return "v1.5.0";
@@ -18,21 +20,30 @@ int WiFiClass::begin(const char *ssid, const char *passphrase, wl_enc_type secur
 	sta_config.ssid_length = strlen(ssid);
 	sta_config.psk = (const uint8_t *)passphrase;
 	sta_config.psk_length = strlen(passphrase);
-	// TODO: change these fields with scan() results
-	sta_config.security = WIFI_SECURITY_TYPE_PSK;
-	sta_config.channel = WIFI_CHANNEL_ANY;
-	sta_config.band = WIFI_FREQ_BAND_2_4_GHZ;
-	sta_config.bandwidth = WIFI_FREQ_BANDWIDTH_20MHZ;
-	int ret = net_mgmt(NET_REQUEST_WIFI_CONNECT, sta_iface, &sta_config,
-					   sizeof(struct wifi_connect_req_params));
-	if (ret) {
-		return false;
-	}
-	NetworkInterface::begin(false, NET_EVENT_WIFI_MASK);
-	if (blocking) {
-		net_mgmt_event_wait_on_iface(sta_iface, NET_EVENT_WIFI_CONNECT_RESULT, NULL, NULL, NULL,
-									 K_FOREVER);
+
+	// Register the Wi-Fi event callback
+	net_mgmt_init_event_callback(&wifiCb, scanEventDispatcher,
+								 NET_EVENT_WIFI_SCAN_RESULT | NET_EVENT_WIFI_SCAN_DONE);
+
+	net_mgmt_add_event_callback(&wifiCb);
+
+	(void)scanNetworks();
+
+	// Check if the network we were seekin was found and attempt to connect to it
+	if (getSoughtNetworkFound() != true) {
+		int ret = net_mgmt(NET_REQUEST_WIFI_CONNECT, sta_iface, &sta_config,
+						   sizeof(struct wifi_connect_req_params));
+		if (ret) {
+			return false;
+		}
+
+		NetworkInterface::begin(false, NET_EVENT_WIFI_MASK);
+		if (blocking) {
+			net_mgmt_event_wait_on_iface(sta_iface, NET_EVENT_WIFI_CONNECT_RESULT, NULL, NULL, NULL,
+										 K_FOREVER);
+		}
 	}
+
 	return status();
 }
 
@@ -79,7 +90,18 @@ int WiFiClass::status() {
 }
 
 int8_t WiFiClass::scanNetworks() {
-	// TODO: borrow code from mbed core for scan results handling
+	resultCount = 0u;
+	setScanSequenceFinished(false);
+	setSoughtNetworkFound(false);
+
+	// Trigger a new scan
+	net_mgmt(NET_REQUEST_WIFI_SCAN, sta_iface, nullptr, 0u);
+
+	// Wait for the scan to finish. This is by design a blocking call
+	while (getScanSequenceFinished() != true)
+		;
+
+	return resultCount;
 }
 
 char *WiFiClass::SSID() {

libraries/WiFi/src/WiFi.h

@@ -3,6 +3,9 @@
 #include "utility/wl_definitions.h"
 #include <zephyr/net/wifi_mgmt.h>
 
+// Max number of scan results to store
+#define MAX_SCAN_RESULTS 20
+
 #define NET_EVENT_WIFI_MASK                                                                        \
 	(NET_EVENT_WIFI_CONNECT_RESULT | NET_EVENT_WIFI_DISCONNECT_RESULT |                            \
 	 NET_EVENT_WIFI_AP_ENABLE_RESULT | NET_EVENT_WIFI_AP_DISABLE_RESULT |                          \
@@ -31,6 +34,62 @@ class WiFiClass : public NetworkInterface {
 
 	String firmwareVersion();
 
+	static void scanEventDispatcher(struct net_mgmt_event_callback *cb, uint64_t mgmt_event,
+									struct net_if *iface) {
+		if (instance != nullptr) {
+			instance->handleScanEvent(cb, mgmt_event, iface);
+		}
+	}
+
+	void handleScanEvent(struct net_mgmt_event_callback *cb, uint64_t mgmt_event,
+						 struct net_if *iface) {
+		if (mgmt_event == NET_EVENT_WIFI_SCAN_RESULT) {
+			const struct wifi_scan_result *entry =
+				reinterpret_cast<const struct wifi_scan_result *>(cb->info);
+			if (resultCount < MAX_SCAN_RESULTS) {
+				memcpy(&scanResults[resultCount], entry, sizeof(struct wifi_scan_result));
+				resultCount++;
+
+				// for each new result found, compare network name with desired one
+				if (!memcmp(entry->ssid, sta_config.ssid, entry->ssid_length)) {
+					// if a match is found, add missing info to config before attempting to connect
+					sta_config.security = entry->security;
+					sta_config.channel = entry->channel;
+					sta_config.band = entry->band;
+					sta_config.bandwidth = WIFI_FREQ_BANDWIDTH_20MHZ;
+
+					setSoughtNetworkFound(true);
+				}
+			}
+		}
+
+		if (mgmt_event == NET_EVENT_WIFI_SCAN_DONE) {
+			setScanSequenceFinished(true);
+
+			if (resultCount = 0) {
+				printk("No networks found.\n");
+			}
+		}
+	}
+
+	void setScanSequenceFinished(bool scanFinished) {
+		scanSequenceFinished = scanFinished;
+	}
+
+	void setSoughtNetworkFound(bool networkFound) {
+		soughtNetworkFound = networkFound;
+	}
+
+	bool getScanSequenceFinished(void) {
+		return scanSequenceFinished;
+	}
+
+	bool getSoughtNetworkFound(void) {
+		return soughtNetworkFound;
+	}
+
+	static WiFiClass *instance;
+
 private:
 	struct net_if *sta_iface = nullptr;
 	struct net_if *ap_iface = nullptr;
@@ -39,6 +98,13 @@ class WiFiClass : public NetworkInterface {
 	struct wifi_connect_req_params sta_config;
 
 	struct wifi_iface_status sta_state = {0};
+
+	struct wifi_scan_result scanResults[MAX_SCAN_RESULTS];
+	uint8_t resultCount;
+	struct net_mgmt_event_callback wifiCb;
+
+	bool soughtNetworkFound = false;
+	bool scanSequenceFinished = false;
 };
 
 extern WiFiClass WiFi;

loader/llext_exports.c

@@ -113,6 +113,7 @@ FORCE_EXPORT_SYM(tls_credential_add);
 FORCE_EXPORT_SYM(net_if_get_wifi_sta);
 FORCE_EXPORT_SYM(net_if_get_wifi_sap);
 FORCE_EXPORT_SYM(net_mgmt_NET_REQUEST_WIFI_CONNECT);
+FORCE_EXPORT_SYM(net_mgmt_NET_REQUEST_WIFI_SCAN);
 FORCE_EXPORT_SYM(net_mgmt_NET_REQUEST_WIFI_IFACE_STATUS);
 FORCE_EXPORT_SYM(net_mgmt_NET_REQUEST_WIFI_AP_ENABLE);
 #endif