main/task_wifi.c

/**
 * @file task_wifi.c
 * @brief WiFi task. Connect to the known AP with the strongest signal.
 */


#include "config.h"


static const char *TAG = "task_wifi";


SemaphoreHandle_t       	xSemaphoreWiFi = NULL;		///< Semaphore WiFi task.
EventGroupHandle_t		xEventGroupWifi;		///< Events WiFi task.
uint16_t			ap_num = MAX_AP_NUM;		///< Scan counter.
wifi_ap_record_t		*accessp_records;		///< [MAX_AP_NUM] records array with scan results.
wifi_config_t			*task_wifi_ConfigSTA = NULL;	///< Current STA configuration.
WIFI_State			*wifi_state = NULL;		///< Public state for other tasks.

wifi_scan_config_t scan_config = {				///< WiFi scanner configuration.
	.ssid = 0,
	.bssid = 0,
	.channel = 0,
	.show_hidden = false,
	.scan_time.passive = 130				///< Beacons are usually sent every 100 mSec.
};

uint8_t				_wifi_ssid[33];			///< Current SSID
bool				_wifi_ScanAPs = false;		///< Scanning
bool				_wifi_ScanDone = false;		///< Scan ready
uint16_t			_wifi_Scanned = 0;		///< Total scanned APs.

extern uint32_t			TimeSpent;			///< Counter that is increased each second.
extern bool			System_TimeOk;
extern time_t			now;
extern char			strftime_buf[64];
extern struct tm		timeinfo;

const int TASK_WIFI_REQUEST_WIFI_SCAN = BIT0;			///< When set, means a client requested to scan wireless networks.
const int TASK_WIFI_REQUEST_STA_DISCONNECT = BIT1;		///< When set, means a client requested to disconnect from currently connected AP.
const int TASK_WIFI_REQUEST_STA_CONNECT = BIT2;			///< When set, means a client requested to connect to an access point.

const int TASK_WIFI_HAS_IP = BIT3;				///< Indicate that we have an IP address
const int TASK_WIFI_STA_FAILED = BIT4;				///< Indicate that we could not get a connection to AP as station.
const int TASK_WIFI_STA_DISCONNECTED = BIT5;			///< Indicate that we are disconnected from an ap station.
const int TASK_WIFI_STA_CONNECTED = BIT6;			///< Indicate that we are connected to AP as station, flip of BIT6.

const int TASK_WIFI_REQUEST_SYSTEM = BIT8;			///< The system needs a connection
const int TASK_WIFI_REQUEST_USER = BIT9;			///< The user needs a connection


/**
 * @brief local callback function. Is called when the timesync is valid
 *        from a timeserver. Sets the global boolean System_TimeOk value. 
 * @param tv is the received time. Not used.
 */
//void time_sync_notification_cb(struct timeval *tv);

/**
 * @brief Array with AP security names
 */
const char *apsec[] = { "Open", "WEP", "WPA", "WPA2", "WPA WPA2", "Enterprise" };


/****************************************************************************/


void requestWiFi_system(bool state)
{
    if (state)
	xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_REQUEST_SYSTEM);
    else
        xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_REQUEST_SYSTEM);

    if (xEventGroupGetBits(xEventGroupWifi) & (TASK_WIFI_REQUEST_SYSTEM | TASK_WIFI_REQUEST_USER))
	xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_REQUEST_STA_CONNECT);
    else
	xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_REQUEST_STA_DISCONNECT);
}


void requestWiFi_user(bool state)
{
    if (state)
        xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_REQUEST_USER);
    else
        xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_REQUEST_USER);

    if (xEventGroupGetBits(xEventGroupWifi) & (TASK_WIFI_REQUEST_SYSTEM | TASK_WIFI_REQUEST_USER))
        xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_REQUEST_STA_CONNECT);
    else
        xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_REQUEST_STA_DISCONNECT);
}


bool ready_WiFi(void)
{
    if (wifi_state->STA_connected && wifi_state->STA_online)
        return true;
    return false;
}


static void wifi_event_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data)
{
    switch (event_id) {

	case WIFI_EVENT_SCAN_DONE:
            // Get the results so the memory used is freed.
            ESP_ERROR_CHECK(esp_wifi_scan_get_ap_records(&ap_num, accessp_records));
            _wifi_Scanned = ap_num;
            _wifi_ScanDone = true;
	    break;

	case WIFI_EVENT_STA_START:
	    ESP_LOGI(TAG, "Event wifi START");
            // Set the configured hostname for the dhcp client.
            ESP_ERROR_CHECK(tcpip_adapter_set_hostname(TCPIP_ADAPTER_IF_STA, config.hostname));
            esp_wifi_connect();
	    break;

	case WIFI_EVENT_STA_CONNECTED:
	    {
		wifi_event_sta_connected_t* event = (wifi_event_sta_connected_t*) event_data;
                wifi_ap_record_t ap_info;
                esp_wifi_sta_get_ap_info(&ap_info);
		ESP_LOGI(TAG, "Event STA connected, ssid:%s, bssid:" MACSTR ", channel:%d, rssi: %d, authmode:%s",
                       ap_info.ssid, MAC2STR(ap_info.bssid), event->channel, ap_info.rssi, apsec[event->authmode]);
                if (xSemaphoreTake(xSemaphoreWiFi, 35) == pdTRUE) {
                    wifi_state->STA_connected = true;
                    wifi_state->STA_rssi = ap_info.rssi;
                    sprintf(wifi_state->STA_ssid, "%s", ap_info.ssid);
                    xSemaphoreGive(xSemaphoreWiFi);
                } else {
		    ESP_LOGE(TAG, "wifi_event_handler() lock error WIFI_EVENT_STA_CONNECTED");
		}
                xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_STA_CONNECTED);
                xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_STA_DISCONNECTED);
	    	break;
	    }

	case WIFI_EVENT_STA_DISCONNECTED:
	    {
		wifi_event_sta_disconnected_t* disconnected = (wifi_event_sta_disconnected_t*) event_data;

                ESP_LOGI(TAG, "Event STA disconnected, ssid:%s, ssid_len:%d, bssid:" MACSTR ", reason:%d",
                       disconnected->ssid, disconnected->ssid_len, MAC2STR(disconnected->bssid), disconnected->reason);
                if (xSemaphoreTake(xSemaphoreWiFi, 35) == pdTRUE) {
                    wifi_state->STA_connected = false;
                    wifi_state->STA_online = false;
                    wifi_state->STA_rssi = 0;
                    xSemaphoreGive(xSemaphoreWiFi);
                } else {
		    ESP_LOGE(TAG, "wifi_event_handler() lock error WIFI_EVENT_STA_DISCONNECTED");
		}
                xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_STA_CONNECTED);
                xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_STA_DISCONNECTED);
		break;
	    }

	default:
	    ESP_LOGW(TAG, "Unknown WiFi event %d", event_id);
	    break;
    }
}


static void got_ip_event_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data)
{
    switch (event_id) {

	case IP_EVENT_STA_GOT_IP:
            xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_HAS_IP);
	    ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
	    if (xSemaphoreTake(xSemaphoreWiFi, 25) == pdTRUE) {
            	wifi_state->STA_online = true;
		snprintf(wifi_state->STA_ip, 16, "%s", ip4addr_ntoa(&event->ip_info.ip));
                snprintf(wifi_state->STA_nm, 16, "%s", ip4addr_ntoa(&event->ip_info.netmask));
                snprintf(wifi_state->STA_gw, 16, "%s", ip4addr_ntoa(&event->ip_info.gw));
                xSemaphoreGive(xSemaphoreWiFi);
	    } else {
		ESP_LOGE(TAG, "got_ip_event_handler() lock error IP_EVENT_STA_GOT_IP");
	    }
	    break;

	case IP_EVENT_STA_LOST_IP:
            ESP_LOGW(TAG, "Lost IP address");
            xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_HAS_IP);
            if (xSemaphoreTake(xSemaphoreWiFi, 25) == pdTRUE) {
                wifi_state->STA_ip[0] = '\0';
                wifi_state->STA_nm[0] = '\0';
                wifi_state->STA_gw[0] = '\0';
                wifi_state->STA_online = false;
                xSemaphoreGive(xSemaphoreWiFi);
            } else {
                ESP_LOGE(TAG, "got_ip_event_handler() lock error IP_EVENT_STA_LOST_IP");
            }
	    break;

	default:
	    ESP_LOGW(TAG, "Unknown IP event %d", event_id);
	    break;
    }
}


void task_wifi( void * pvParameters )
{
    ESP_LOGI(TAG, "Starting WiFi");

    /* event handler and event group for the wifi driver */
    xEventGroupWifi = xEventGroupCreate();
    /* initialize the tcp stack */
    tcpip_adapter_init();
    ESP_ERROR_CHECK(esp_event_loop_create_default());

    /*
     * memory allocation of objects used by the task 
     */
    accessp_records = (wifi_ap_record_t*)malloc(sizeof(wifi_ap_record_t) * MAX_AP_NUM);
    task_wifi_ConfigSTA = (wifi_config_t*)malloc(sizeof(wifi_config_t));
    memset(task_wifi_ConfigSTA, 0x00, sizeof(wifi_config_t));

    xSemaphoreWiFi = xSemaphoreCreateMutex();
    wifi_state = malloc(sizeof(WIFI_State));
    memset(wifi_state, 0x00, sizeof(WIFI_State));

    /* stop dhcp server and start dhcp client */
    ESP_ERROR_CHECK(tcpip_adapter_dhcps_stop(TCPIP_ADAPTER_IF_AP));
    ESP_ERROR_CHECK(tcpip_adapter_dhcpc_start(TCPIP_ADAPTER_IF_STA));

    /*
     * init wifi as station
     */
    wifi_init_config_t wifi_init_config = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&wifi_init_config));

    ESP_ERROR_CHECK( esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &wifi_event_handler, NULL) );
    ESP_ERROR_CHECK( esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &got_ip_event_handler, NULL) );

    ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_start());

    xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_STA_DISCONNECTED);
    EventBits_t uxBits;

    for(;;) {

	/* actions that can trigger: request a connection, a scan, or a disconnection */
	uxBits = xEventGroupWaitBits(xEventGroupWifi, 
		                     TASK_WIFI_REQUEST_STA_CONNECT | TASK_WIFI_REQUEST_WIFI_SCAN | TASK_WIFI_REQUEST_STA_DISCONNECT,
		                     pdFALSE, pdFALSE, portMAX_DELAY );

	if (uxBits & TASK_WIFI_REQUEST_STA_DISCONNECT) {
	    /*
	     * user requested a disconnect, this will in effect disconnect the wifi
	     */
	    ESP_LOGD(TAG, "Request STA disconnect");
	    ESP_ERROR_CHECK(esp_wifi_disconnect());
	    xEventGroupWaitBits(xEventGroupWifi, TASK_WIFI_STA_DISCONNECTED, pdFALSE, pdTRUE, portMAX_DELAY );

	    /* finally: release the scan request bit */
	    xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_REQUEST_STA_DISCONNECT);

	} else if (uxBits & TASK_WIFI_REQUEST_STA_CONNECT) {

	    ESP_LOGD(TAG, "Request STA connect");
	    xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_STA_FAILED);
            _wifi_ScanAPs = true;
            _wifi_ScanDone = false;
            ap_num = MAX_AP_NUM;
            ESP_ERROR_CHECK(esp_wifi_scan_start(&scan_config, false));
	    while (_wifi_ScanDone == false) {
		vTaskDelay(10 / portTICK_PERIOD_MS);
            }
	    ESP_LOGI(TAG, "Scan done %d APs", _wifi_Scanned);
	    bool found = false;

            // Available Access Points.
            for (int i = 0; i < _wifi_Scanned; i++) {
		wifi_ap_record_t ap = accessp_records[i];
		// Check if we know this AP in the database.
		ESP_LOGD(TAG, "%d %-20s ch: %2d rssi: %d %s", i, ap.ssid, ap.primary, ap.rssi, apsec[ap.authmode]);
		if ((read_station(ap.ssid) >= 0)) {
		    /* ssid */
		    size_t sz = sizeof(task_wifi_ConfigSTA->sta.ssid);
		    memcpy(task_wifi_ConfigSTA->sta.ssid, wifiStation.SSID, sz);
		    /* password */
		    sz = sizeof(task_wifi_ConfigSTA->sta.password);
		    memcpy(task_wifi_ConfigSTA->sta.password, wifiStation.Password, sz);
		    found = true;
		    break;
		}
	    }
	    if (found) {
		/*
		 * Now connect to the known SSID
		 */
		ESP_LOGD(TAG, "Connecting to `%s'", task_wifi_ConfigSTA->sta.ssid);
		ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, task_wifi_ConfigSTA));
		esp_err_t wifierror = esp_wifi_connect();
		if (wifierror != ESP_OK) {
		    ESP_LOGE(TAG, "esp_wifi_connect() `%s' rc=%04x", task_wifi_ConfigSTA->sta.ssid, (int)wifierror);
		    xEventGroupSetBits(xEventGroupWifi, TASK_WIFI_STA_FAILED);
		}
		uxBits = xEventGroupWaitBits(xEventGroupWifi, TASK_WIFI_STA_CONNECTED | TASK_WIFI_STA_FAILED, pdFALSE, pdFALSE, 5000 / portTICK_PERIOD_MS);
		if (uxBits & TASK_WIFI_STA_CONNECTED)
		    xEventGroupClearBits(xEventGroupWifi, TASK_WIFI_REQUEST_STA_CONNECT); // Only clear when connected.
	    } else {
		ESP_LOGI(TAG, "No known AP found, scan again");
		vTaskDelay(3000 / portTICK_PERIOD_MS);
	    }
	}

    } /* for(;;) */
    vTaskDelay(10 / portTICK_PERIOD_MS);
}