esp-firewall/ESPTest/src/main.c

#include "theSecrets.h"
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include <esp_http_server.h>

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

static const char *WIFI_TAG = "wifi station";
static const char *SERVER_TAG = "http server";

int my_hook(struct pbuf *pbuf, struct netif *input_netif)
{
    ESP_LOGI(WIFI_TAG, "TESTING!");
    return ESP_OK;
}

#define LWIP_HOOK_IP4_INPUT(pbuf, input_netif) my_hook(pbuf, input_netif)

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

/* The event group allows multiple bits for each event, but we only care about two events:
 * - we are connected to the AP with an IP
 * - we failed to connect after the maximum amount of retries */
#define WIFI_CONNECTED_BIT BIT0
#define WIFI_FAIL_BIT BIT1

static int s_retry_num = 0;

static void event_handler(void *arg, esp_event_base_t event_base,
                          int32_t event_id, void *event_data)
{
    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START)
    {
        esp_wifi_connect();
    }
    else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED)
    {
        if (s_retry_num < 10)
        {
            esp_wifi_connect();
            s_retry_num++;
            ESP_LOGI(WIFI_TAG, "retry to connect to the AP");
        }
        else
        {
            xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
        }
        ESP_LOGI(WIFI_TAG, "connect to the AP fail");
    }
    else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP)
    {
        ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
        ESP_LOGI(WIFI_TAG, "got ip:" IPSTR, IP2STR(&event->ip_info.ip));
        s_retry_num = 0;
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
    }
}

void wifi_init_sta(void)
{
    s_wifi_event_group = xEventGroupCreate();

    ESP_ERROR_CHECK(esp_netif_init());

    ESP_ERROR_CHECK(esp_event_loop_create_default());
    esp_netif_create_default_wifi_sta();

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    esp_event_handler_instance_t instance_any_id;
    esp_event_handler_instance_t instance_got_ip;
    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
                                                        ESP_EVENT_ANY_ID,
                                                        &event_handler,
                                                        NULL,
                                                        &instance_any_id));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT,
                                                        IP_EVENT_STA_GOT_IP,
                                                        &event_handler,
                                                        NULL,
                                                        &instance_got_ip));

    wifi_config_t wifi_config = {
        .sta = {
            .ssid = SSID,
            .password = PSK,
        },
    };
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());

    ESP_LOGI(WIFI_TAG, "wifi_init_sta finished.");

    /* Waiting until either the connection is established (WIFI_CONNECTED_BIT) or connection failed for the maximum
     * number of re-tries (WIFI_FAIL_BIT). The bits are set by event_handler() (see above) */
    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
                                           WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
                                           pdFALSE,
                                           pdFALSE,
                                           portMAX_DELAY);

    /* xEventGroupWaitBits() returns the bits before the call returned, hence we can test which event actually
     * happened. */
    if (bits & WIFI_CONNECTED_BIT)
    {
        ESP_LOGI(WIFI_TAG, "connected to ap");
    }
    else if (bits & WIFI_FAIL_BIT)
    {
        ESP_LOGI(WIFI_TAG, "Failed to connect");
    }
    else
    {
        ESP_LOGE(WIFI_TAG, "UNEXPECTED EVENT");
    }
}

static esp_err_t hello_get_handler(httpd_req_t *req)
{
    /* Send response with custom headers and body set as the
     * string passed in user context*/
    const char *resp_str = (const char *)req->user_ctx;
    httpd_resp_send(req, resp_str, HTTPD_RESP_USE_STRLEN);
    return ESP_OK;
}

static const httpd_uri_t hello = {
    .uri = "/hello",
    .method = HTTP_GET,
    .handler = hello_get_handler,
    .user_ctx = "Hello World!"};

static httpd_handle_t start_webserver(void)
{
    httpd_handle_t server = NULL;
    httpd_config_t config = HTTPD_DEFAULT_CONFIG();
    config.lru_purge_enable = true;

    // Start the httpd server
    ESP_LOGI(SERVER_TAG, "Starting server on port: '%d'", config.server_port);
    if (httpd_start(&server, &config) == ESP_OK)
    {
        // Set URI handlers
        ESP_LOGI(SERVER_TAG, "Registering URI handlers");
        httpd_register_uri_handler(server, &hello);
        return server;
    }

    ESP_LOGI(SERVER_TAG, "Error starting server!");
    return NULL;
}

static esp_err_t stop_webserver(httpd_handle_t server)
{
    // Stop the httpd server
    return httpd_stop(server);
}

static void disconnect_handler(void *arg, esp_event_base_t event_base,
                               int32_t event_id, void *event_data)
{
    httpd_handle_t *server = (httpd_handle_t *)arg;
    if (*server)
    {
        ESP_LOGI(SERVER_TAG, "Stopping webserver");
        if (stop_webserver(*server) == ESP_OK)
        {
            *server = NULL;
        }
        else
        {
            ESP_LOGE(SERVER_TAG, "Failed to stop http server");
        }
    }
}

static void connect_handler(void *arg, esp_event_base_t event_base,
                            int32_t event_id, void *event_data)
{
    httpd_handle_t *server = (httpd_handle_t *)arg;
    if (*server == NULL)
    {
        ESP_LOGI(SERVER_TAG, "Starting webserver");
        *server = start_webserver();
    }
}

void app_main(void)
{
    static httpd_handle_t server = NULL;

    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND)
    {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK(ret);

    ESP_LOGI(WIFI_TAG, "ESP_WIFI_MODE_STA");
    wifi_init_sta();

    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &connect_handler, &server));
    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, WIFI_EVENT_STA_DISCONNECTED, &disconnect_handler, &server));
    server = start_webserver();
}