ESP32-C3 esp-idf 4.3.5 连入指定无线网后向指定ip发送数据

在 ESP32-C3 的 STA 模式下，可以通过 ESP-IDF 中提供的 Wi-Fi 库连接到指定的无线网络，然后向指定 IP 发送数据。具体步骤如下：

1. 配置 Wi-Fi 连接：

#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"

#define WIFI_SSID "无线网络名称"
#define WIFI_PASS "无线网络密码"

static esp_err_t wifi_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_CONNECTED:
            ESP_LOGI(TAG, "Connected to AP");
            break;
        case SYSTEM_EVENT_STA_GOT_IP:
            ESP_LOGI(TAG, "Got IP address");
            break;
        case SYSTEM_EVENT_STA_DISCONNECTED:
            ESP_LOGI(TAG, "Disconnected from AP");
            esp_wifi_connect();
            break;
        default:
            break;
    }
    return ESP_OK;
}

void wifi_init_sta(void)
{
    tcpip_adapter_init();
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    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, &wifi_event_handler, NULL));
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = WIFI_SSID,
            .password = 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());
}

2. 创建一个 TCP 连接并连接到指定 IP：

#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

void send_data_to_ip(void)
{
    // 创建目标地址
    struct sockaddr_in dest_addr;
    dest_addr.sin_addr.s_addr = inet_addr("目标IP地址");
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port = htons(目标端口);

    // 创建 socket
    int socket_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (socket_fd < 0) {
        printf("Failed to create socket\n");
        return;
    }

    // 连接到目标地址
    if (connect(socket_fd, (struct sockaddr *)&dest_addr, sizeof(dest_addr)) != 0) {
        printf("Failed to connect to server\n");
        close(socket_fd);
        return;
    }

    // 发送数据
    const char *data = "要发送的数据";
    if (send(socket_fd, data, strlen(data), 0) < 0) {
        printf("Failed to send data\n");
        close(socket_fd);
        return;
    }

    // 关闭连接
    close(socket_fd);
}

3. 完整的代码示例：

#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define WIFI_SSID "无线网络名称"
#define WIFI_PASS "无线网络密码"

static esp_err_t wifi_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_CONNECTED:
            ESP_LOGI(TAG, "Connected to AP");
            break;
        case SYSTEM_EVENT_STA_GOT_IP:
            ESP_LOGI(TAG, "Got IP address");
            send_data_to_ip();
            break;
        case SYSTEM_EVENT_STA_DISCONNECTED:
            ESP_LOGI(TAG, "Disconnected from AP");
            esp_wifi_connect();
            break;
        default:
            break;
    }
    return ESP_OK;
}

void wifi_init_sta(void)
{
    tcpip_adapter_init();
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    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, &wifi_event_handler, NULL));
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = WIFI_SSID,
            .password = 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());
}

void send_data_to_ip(void)
{
    // 创建目标地址
    struct sockaddr_in dest_addr;
    dest_addr.sin_addr.s_addr = inet_addr("目标IP地址");
    dest_addr.sin_family = AF_INET;
    dest_addr.sin_port = htons(目标端口);

    // 创建 socket
    int socket_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (socket_fd < 0) {
        printf("Failed to create socket\n");
        return;
    }

    // 连接到目标地址
    if (connect(socket_fd, (struct sockaddr *)&dest_addr, sizeof(dest_addr)) != 0) {
        printf("Failed to connect to server\n");
        close(socket_fd);
        return;
    }

    // 发送数据
    const char *data = "要发送的数据";
    if (send(socket_fd, data, strlen(data), 0) < 0) {
        printf("Failed to send data\n");
        close(socket_fd);
        return;
    }

    // 关闭连接
    close(socket_fd);
}

需要注意的是，以上代码仅提供了一个示例，实际应用中需要根据具体需求进行修改和完善。