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| #include <string.h>
#include <sys/param.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "esp_netif.h"
#include "protocol_examples_common.h"
#include "lwip/err.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include <lwip/netdb.h>
#define WIFI_SSID "Your_AP_SSID"
#define WIFI_PASS "Your_AP_Password"
#define UDP_PORT 12345
static const char *TAG = "example";
void udp_server_task(void *pvParameters) {
struct sockaddr_in server_addr, client_addr;
int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
if (sock < 0) {
ESP_LOGE(TAG, "Unable to create socket: errno %d", errno);
vTaskDelete(NULL);
return;
}
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(UDP_PORT);
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
ESP_LOGE(TAG, "Socket unable to bind: errno %d", errno);
vTaskDelete(NULL);
return;
}
ESP_LOGI(TAG, "UDP server listening");
while (1) {
char rx_buffer[128];
int len = sizeof(client_addr);
int rx_len = recvfrom(sock, rx_buffer, sizeof(rx_buffer) - 1, 0, (struct sockaddr *)&client_addr, &len);
if (rx_len <= 0) {
ESP_LOGE(TAG, "recvfrom failed: errno %d", errno);
break;
} else {
rx_buffer[rx_len] = '\0';
ESP_LOGI(TAG, "Received %d bytes from %s:%d", rx_len, inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port));
ESP_LOGI(TAG, "%s", rx_buffer);
sendto(sock, rx_buffer, rx_len, 0, (struct sockaddr *)&client_addr, sizeof(client_addr));
}
}
if (sock != -1) {
ESP_LOGE(TAG, "Shutting down socket and restarting...");
shutdown(sock, 0);
close(sock);
}
vTaskDelete(NULL);
}
void app_main() {
nvs_flash_init();
ESP_ERROR_CHECK(esp_netif_init());
ESP_ERROR_CHECK(esp_event_loop_create_default());
esp_netif_create_default_wifi_ap();
wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
ESP_ERROR_CHECK(esp_wifi_init(&cfg));
wifi_config_t wifi_config = {
.ap = {
.ssid = WIFI_SSID,
.ssid_len = strlen(WIFI_SSID),
.password = WIFI_PASS,
.max_connection = 4,
.authmode = WIFI_AUTH_WPA_WPA2_PSK
},
};
ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &wifi_config));
ESP_ERROR_CHECK(esp_wifi_start());
xTaskCreate(udp_server_task, "udp_server_task", 4096, NULL, 5, NULL);
}
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