esp-idf/examples/protocols/asio/tcp_echo_server/components/wifi_asio.cpp

/* Common WiFi Init as STA for ASIO examples

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event_loop.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "driver/uart.h"
#include "esp_console.h"
#include "esp_vfs_dev.h"

#include "lwip/err.h"
#include "lwip/sys.h"

#include <cstring>

/* The examples use simple WiFi configuration that you can set via
   'make menuconfig'.

   If you'd rather not, just change the below entries to strings with
   the config you want - ie #define EXAMPLE_WIFI_SSID "mywifissid"
*/
#define EXAMPLE_ESP_WIFI_SSID      CONFIG_ESP_WIFI_SSID
#define EXAMPLE_ESP_WIFI_PASS      CONFIG_ESP_WIFI_PASSWORD

/* FreeRTOS event group to signal when we are connected*/
static EventGroupHandle_t wifi_event_group;

/* The event group allows multiple bits for each event,
   but we only care about one event - are we connected
   to the AP with an IP? */
const int WIFI_CONNECTED_BIT = BIT0;

static const char *TAG = "asio example wifi init";

/**
 *  Definition of ASIO main method, which is called after network initialized
 */
void asio_main();

static esp_err_t event_handler(void *ctx, system_event_t *event)
{
    switch(event->event_id) {
    case SYSTEM_EVENT_STA_START:
        esp_wifi_connect();
        break;
    case SYSTEM_EVENT_STA_GOT_IP:
        ESP_LOGI(TAG, "got ip:%s",
                 ip4addr_ntoa(&event->event_info.got_ip.ip_info.ip));
        xEventGroupSetBits(wifi_event_group, WIFI_CONNECTED_BIT);
        break;
    case SYSTEM_EVENT_AP_STACONNECTED:
        ESP_LOGI(TAG, "station:" MACSTR " join, AID=%d",
                 MAC2STR(event->event_info.sta_connected.mac),
                 event->event_info.sta_connected.aid);
        break;
    case SYSTEM_EVENT_AP_STADISCONNECTED:
        ESP_LOGI(TAG, "station:" MACSTR "leave, AID=%d",
                 MAC2STR(event->event_info.sta_disconnected.mac),
                 event->event_info.sta_disconnected.aid);
        break;
    case SYSTEM_EVENT_STA_DISCONNECTED:
        esp_wifi_connect();
        xEventGroupClearBits(wifi_event_group, WIFI_CONNECTED_BIT);
        break;
    default:
        break;
    }
    return ESP_OK;
}

void wifi_init_sta()
{
    wifi_event_group = xEventGroupCreate();

    tcpip_adapter_init();
    ESP_ERROR_CHECK(esp_event_loop_init(event_handler, NULL) );

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
    wifi_config_t wifi_config;
    // zero out the config struct to ensure defaults are setup
    memset(&wifi_config, 0, sizeof(wifi_sta_config_t));
    // only copy ssid&password from example config
    strcpy((char*)(wifi_config.sta.ssid), EXAMPLE_ESP_WIFI_SSID);
    strcpy((char*)(wifi_config.sta.password), EXAMPLE_ESP_WIFI_PASS);

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA) );
    ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config) );
    ESP_ERROR_CHECK(esp_wifi_start() );

    ESP_LOGI(TAG, "wifi_init_sta finished.");
    ESP_LOGI(TAG, "connect to ap SSID:%s password:%s",
             EXAMPLE_ESP_WIFI_SSID, EXAMPLE_ESP_WIFI_PASS);
}

extern "C" void app_main()
{
    //Initialize NVS
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES) {
      ESP_ERROR_CHECK(nvs_flash_erase());
      ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK(ret);
    
    ESP_LOGI(TAG, "ESP_WIFI_MODE_AP");
    wifi_init_sta();

    // Initialize VFS & UART so we can use std::cout/cin
    setvbuf(stdin, NULL, _IONBF, 0);
    setvbuf(stdout, NULL, _IONBF, 0);
    /* Install UART driver for interrupt-driven reads and writes */
    ESP_ERROR_CHECK( uart_driver_install( (uart_port_t)CONFIG_CONSOLE_UART_NUM,
            256, 0, 0, NULL, 0) );
    /* Tell VFS to use UART driver */
    esp_vfs_dev_uart_use_driver(CONFIG_CONSOLE_UART_NUM);
    esp_vfs_dev_uart_set_rx_line_endings(ESP_LINE_ENDINGS_CR);
    /* Move the caret to the beginning of the next line on '\n' */
    esp_vfs_dev_uart_set_tx_line_endings(ESP_LINE_ENDINGS_CRLF);

    // wait till we receive IP, so asio realated code can be started
    xEventGroupWaitBits(wifi_event_group, WIFI_CONNECTED_BIT, 1, 1, portMAX_DELAY);

    // network is ready, let's proceed with ASIO example
    asio_main();
}