ESP32接入网络后，循环扫描服务器IP及端口状态信息（ESP-IDF） 0、代码说明         本文使用的是ESP32系列的ESP32S3设备开发，ESP-IDF框架版本为ESP-IDF V5.1，在VScode下以ESP-IDF插件的形式对设备开发。后期经过对程序的测试发现，在ESP-IDF v4.4框架下编译开发，也可以实现循环扫描功能，实现功能的程序源码Demo见文末。 1、实现背景         在嵌入式物联网这一类的项目开发中，硬件设备常作为客户端，通过固定的或非固定的服务器IP地址和端口号向服务器进行通信，上传本地数据到服务器中或接收来自服务器的请求数据。本文主要解决当服务器IP地址并未固定或者因某种原因导致服务器的IP地址发生变动，而硬件设备产品可能已经上市交付等其它因素，并不能及时的通过OTA升级更新客户端的MCU硬件程序，但硬件产品依然需要连接服务器的端口，进行数据交互。         为了预防避免这些意外，在硬件设备程序的编写中，并不能和往常一样直接固定了服务器IP地址。本博客文章中提供了一种简单可行的方法，即：客户端固定了目标服务器的IP端口，但服务器的IP地址并不固定。当然，也可以先进行对某一固定了IP和端口的服务器进行连接，在多次或者一定时间都不能正常接入服务器后，开启循环扫描同一网段的服务器IP，连接该固定端口或备用端口。 2、开发资料参考 乐鑫官方的ESP-IDF编程API参考指南链接：API 指南 - ESP32-S3 - — ESP-IDF 编程指南 latest 文档 (espressif.com) 通过API编程参考，可以查看ESP32所需要的常用API及其使用的Demo案例。 3、程序效果图 ESP32接入WiFi网络后获取到的IP地址信息 ESP32扫描到在线的IP地址，但未扫描到对应的端口，如果服务器未开启，则ESP32会一直循环扫描服务器的IP及端口。 ESP32扫描到服务器的IP地址和端口 服务器的IP地址 ESP32接入服务器后，服务器端收到来自客户端发送的数据 4、程序源码  ①、main.c #include #include #include "esp_wifi.h" #include "esp_log.h" #include "nvs_flash.h" #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "network.h" //设备启动接入WiFi后，循环扫描服务器ip是否在线，通信端口是否打开 int app_main() { printf("Program starting...\n"); int ret = 0; char server_ip[128] = {0}; uint8_t wifi_ssid[] = "imi-12-1719"; uint8_t wifi_passwd[] = "imi?61415926"; device_connect_wifi_ap(wifi_ssid, wifi_passwd); vTaskDelay(500); while(1) { ret = device_scan_dest_server(server_ip); if(ret == 0) { printf("Server ip:%s\n", server_ip); break; } vTaskDelay(30000 / portTICK_PERIOD_MS); } //连接服务器 extern int tcp_sock; tcp_client_init(server_ip); char str[] = "hello server!"; send(tcp_sock, str, strlen(str)+1, 0); close(tcp_sock); return 0; } ②、network.c #include "network.h" //ESP-IDF v5.1 static const char *TAG = "wifi_station"; int tcp_sock = -1; int udp_sock = -1; esp_ping_handle_t ping; int ping_flag = -1; enum { PING_IP_OK = 0, PING_IP_ERR }; struct sockaddr_in dest_addr; / * @brief 连接WiFi事件处理器---处理WiFi和IP事件 * @param arg:用户定义的参数 * @param event_base:事件基类型 * @param event_id:事件具体ID * @param event_data:指向事件数据的指针 * @retval void */ void connect_wifi_ap_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) { esp_wifi_connect(); } 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; char addr_str[IP4ADDR_STRLEN_MAX]; ESP_LOGI(TAG, "got ip:%s", esp_ip4addr_ntoa(&event->ip_info.ip, addr_str, IP4ADDR_STRLEN_MAX)); } } / * @brief 设备连接WiFi AP热点 * @param wifi_ssid:WiFi 热点ID * @param wifi_passwd:WiFi密码 * @retval void */ void device_connect_wifi_ap(uint8_t *wifi_ssid, uint8_t *wifi_passwd) { 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_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_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &connect_wifi_ap_event_handler, NULL)); ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &connect_wifi_ap_event_handler, NULL)); wifi_config_t wifi_config; memcpy(wifi_config.sta.ssid, wifi_ssid, strlen((char *)wifi_ssid)+1); memcpy(wifi_config.sta.password, wifi_passwd, strlen((char *)wifi_passwd)+1); 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()); } / * @brief udp客户端初始化 * @param None * @retval 成功返回0，失败返回-1 */ int udp_client_init(void) { char host_ip[] = HOST_IP_ADDR; int addr_family = 0; int ip_protocol = 0; #if defined(CONFIG_EXAMPLE_IPV4) //struct sockaddr_in dest_addr; dest_addr.sin_addr.s_addr = inet_addr(host_ip); dest_addr.sin_family = AF_INET; dest_addr.sin_port = htons(PORT); addr_family = AF_INET; ip_protocol = IPPROTO_IP; #elif defined(CONFIG_EXAMPLE_IPV6) struct sockaddr_in6 dest_addr = {0}; inet6_aton(HOST_IP_ADDR, &dest_addr.sin6_addr); dest_addr.sin6_family = AF_INET6; dest_addr.sin6_port = htons(PORT); dest_addr.sin6_scope_id = esp_netif_get_netif_impl_index(EXAMPLE_INTERFACE); addr_family = AF_INET6; ip_protocol = IPPROTO_IPV6; #elif defined(CONFIG_EXAMPLE_SOCKET_IP_INPUT_STDIN) struct sockaddr_storage dest_addr = {0}; ESP_ERROR_CHECK(get_addr_from_stdin(PORT, SOCK_DGRAM, &ip_protocol, &addr_family, &dest_addr)); #endif extern int udp_sock; udp_sock = socket(addr_family, SOCK_DGRAM, ip_protocol); if (udp_sock < 0) { ESP_LOGE(TAG, "Unable to create socket: errno %d", errno); return -1; } ESP_LOGI(TAG, "Socket created, sending to %s:%d", HOST_IP_ADDR, PORT); return 0; } / * @brief tcp客户端初始化 * @param None * @retval 成功返回0，失败返回-1 */ int tcp_client_init(char ip_addr[]) { //char host_ip[128] = HOST_IP_ADDR; char host_ip[128] = {0}; memcpy(host_ip, ip_addr, strlen(ip_addr)); int addr_family = 0; int ip_protocol = 0; int err = 0; #if defined(CONFIG_EXAMPLE_IPV4) struct sockaddr_in dest_addr; dest_addr.sin_addr.s_addr = inet_addr(host_ip); dest_addr.sin_family = AF_INET; dest_addr.sin_port = htons(PORT); addr_family = AF_INET; ip_protocol = IPPROTO_IP; #elif defined(CONFIG_EXAMPLE_IPV6) struct sockaddr_in6 dest_addr = { 0 }; inet6_aton(host_ip, &dest_addr.sin6_addr); dest_addr.sin6_family = AF_INET6; dest_addr.sin6_port = htons(PORT); dest_addr.sin6_scope_id = esp_netif_get_netif_impl_index(EXAMPLE_INTERFACE); addr_family = AF_INET6; ip_protocol = IPPROTO_IPV6; #elif defined(CONFIG_EXAMPLE_SOCKET_IP_INPUT_STDIN) struct sockaddr_storage dest_addr = { 0 }; ESP_ERROR_CHECK(get_addr_from_stdin(PORT, SOCK_STREAM, &ip_protocol, &addr_family, &dest_addr)); #endif extern int tcp_sock; tcp_sock = socket(addr_family, SOCK_STREAM, ip_protocol); if (tcp_sock < 0) { ESP_LOGE(TAG, "Unable to create socket: errno %d", errno); return -1; } ESP_LOGI(TAG, "Socket created, connecting to server"); DPRINTF("Socket created, connecting to %s:%d\n", host_ip, PORT); err = connect(tcp_sock, (struct sockaddr *)&dest_addr, sizeof(struct sockaddr_in6)); if (err != 0) { ESP_LOGE(TAG, "Socket unable to connect: errno %d", errno); return -1; } ESP_LOGI(TAG, "Successfully connected"); return 0; } / * @brief 设备连接服务器 * @param target_ip:目标IP地址 * @retval 成功返回0，失败返回-1 */ int device_connect_to_server(char *target_ip) { int sock = 0; struct sockaddr_in serv_addr; //#define PORT 5005 DPRINTF("FUNCTION:%s\tLINE:%d\n", __FUNCTION__, __LINE__); if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) { DPRINTF("\n Socket creation error \n"); close(sock); return -1; } DPRINTF("FUNCTION:%s\tLINE:%d\n", __FUNCTION__, __LINE__); memset(&serv_addr, '0', sizeof(serv_addr)); serv_addr.sin_family = AF_INET; serv_addr.sin_port = htons(PORT); if(inet_pton(AF_INET, target_ip, &serv_addr.sin_addr)<=0) { DPRINTF("\nInvalid address/ Address not supported \n"); close(sock); return -1; } DPRINTF("FUNCTION:%s\tLINE:%d\n", __FUNCTION__, __LINE__); if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) { //send(sock, "hello", strlen("hello"), 0); DPRINTF("\nConnection Failed %s\t%d\n", target_ip, PORT); close(sock); return -1; } DPRINTF("Connected to %s:%d\n", target_ip, PORT); //char str[] = "hello server!"; //send(sock, str, strlen(str)+1, 0); close(sock); return 0; } / * @brief TCP扫描同一网段下的目标服务器设备 * @param target_ip:目标IP地址 * @retval 成功返回0， 失败返回-1 */ int device_scan_dest_server(char ip_addr[]) { char ip_local_addr[128] = {0}; char ip_search_addr[256] = {0}; esp_netif_t *netif = esp_netif_get_handle_from_ifkey("WIFI_STA_DEF"); esp_netif_ip_info_t ip_info; esp_netif_get_ip_info(netif, &ip_info); memcpy(ip_local_addr, ip4addr_ntoa((ip4_addr_t *)&ip_info.ip), strlen(ip4addr_ntoa((ip4_addr_t *)&ip_info.ip))); //char *ip4addr_ntoa(const ip4_addr_t *addr); printf("device ip:%s\n", ip_local_addr); //192.168.1.8 int i, self_ip_com = 0; int tok_cnt = 1; int ret = -1; for(i = 0; i < 128; i++) { if(ip_local_addr[i] == '.')//获取所在网段 { if(tok_cnt == 3) { self_ip_com = ip_local_addr[i+1] - '0'; break; } tok_cnt++; } //DPRINTF("%c %d\n", ip_local_addr[i], i); } DPRINTF("self_ip_com:%d\n", self_ip_com); DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); char ip_addr_temp[128] = {0}; strncpy(ip_addr_temp, ip_local_addr, i+1); DPRINTF("%s\n", ip_addr_temp); int com; for(com = 1; com < 255; com++) { if(com == self_ip_com) continue; sprintf(ip_search_addr, "%s%d", ip_addr_temp, com); //DPRINTF("%s\n", ip_search_addr); DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); device_ping_ip_addr(ip_search_addr);//ping传入的ip地址 vTaskDelay(500 / portTICK_PERIOD_MS); //ping通ip地址后，继续判断是否能够连接端口(5005) if(ping_flag == PING_IP_OK) { esp_ping_stop(ping); esp_ping_delete_session(ping); DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); ret = device_connect_to_server(ip_search_addr); if (ret == 0) { DPRINTF("Found the target server.\n"); memcpy(ip_addr, ip_search_addr, strlen(ip_search_addr)); break; } }else{ DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); //vTaskDelay(300 / portTICK_PERIOD_MS); esp_ping_stop(ping); esp_ping_delete_session(ping); } DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); //DPRINTF("try again.\n"); memset(ip_search_addr, 0, sizeof(ip_search_addr)); } DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); printf("com = %d\n", com); if(com < 255) { DPRINTF("Device scan server success.\n"); return 0; }else{ DPRINTF("Device scan server failed.\n"); return -1; } } / * @brief ping ip地址成功的回调函数 * @param handle:ping ip句柄 * @param args:传入给回调函数的参数 * @retval None */ void ping_ip_success(esp_ping_handle_t handle, void *args) { // optionally, get callback arguments // const char* str = (const char*) args; // DPRINTF("%s\r\n", str); // "foo" ping_flag = PING_IP_OK; uint8_t ttl; uint16_t seqno; uint32_t elapsed_time, recv_len; ip_addr_t target_addr; esp_ping_get_profile(handle, ESP_PING_PROF_SEQNO, &seqno, sizeof(seqno)); esp_ping_get_profile(handle, ESP_PING_PROF_TTL, &ttl, sizeof(ttl)); esp_ping_get_profile(handle, ESP_PING_PROF_IPADDR, &target_addr, sizeof(target_addr)); esp_ping_get_profile(handle, ESP_PING_PROF_SIZE, &recv_len, sizeof(recv_len)); esp_ping_get_profile(handle, ESP_PING_PROF_TIMEGAP, &elapsed_time, sizeof(elapsed_time)); printf("%ld bytes from %s icmp_seq=%d ttl=%d time=%ld ms\n", recv_len, inet_ntoa(target_addr.u_addr.ip4), seqno, ttl, elapsed_time); } / * @brief ping ip地址超时的回调函数 * @param handle:ping ip句柄 * @param args:传入给回调函数的参数 * @retval None */ void ping_ip_timeout(esp_ping_handle_t handle, void *args) { ping_flag = PING_IP_ERR; uint16_t seqno; ip_addr_t target_addr; esp_ping_get_profile(handle, ESP_PING_PROF_SEQNO, &seqno, sizeof(seqno)); esp_ping_get_profile(handle, ESP_PING_PROF_IPADDR, &target_addr, sizeof(target_addr)); printf("From %s icmp_seq=%d timeout\n", inet_ntoa(target_addr.u_addr.ip4), seqno); } / * @brief ping ip地址结束的回调函数 * @param handle:ping ip句柄 * @param args:传入给回调函数的参数 * @retval None */ void ping_ip_end(esp_ping_handle_t handle, void *args) { uint32_t transmitted; uint32_t received; uint32_t total_time_ms; ping_flag = -1; esp_ping_get_profile(handle, ESP_PING_PROF_REQUEST, &transmitted, sizeof(transmitted)); esp_ping_get_profile(handle, ESP_PING_PROF_REPLY, &received, sizeof(received)); esp_ping_get_profile(handle, ESP_PING_PROF_DURATION, &total_time_ms, sizeof(total_time_ms)); DPRINTF("%ld packets transmitted, %ld received, time %ldms\n", transmitted, received, total_time_ms); } / * @brief ping ip地址 * @param ip_str:字符串格式的IP地址 "192.168.1.8" * @retval None */ void device_ping_ip_addr(char *ip_str) { DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); ip_addr_t target_addr; esp_ping_config_t ping_config = ESP_PING_DEFAULT_CONFIG(); ping_config.interval_ms = 400; ping_config.timeout_ms = 400; memset(&target_addr, 0, sizeof(ip_addr_t)); //字符串IP地址转换为ping_addr if (ipaddr_aton(ip_str, &target_addr)) { //DPRINTF("转换成功.\n"); ping_config.target_addr = target_addr; } else { DPRINTF("Invalid IP address\n"); return ; } DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); //ping_config.target_addr = target_addr; // target IP address ping_config.count = ESP_PING_COUNT_INFINITE; // ping in infinite mode, esp_ping_stop can stop it //设置回调函数 esp_ping_callbacks_t cbs; cbs.on_ping_success = ping_ip_success; cbs.on_ping_timeout = ping_ip_timeout; cbs.on_ping_end = ping_ip_end; cbs.cb_args = "ping ip"; // arguments that will feed to all callback functions, can be NULL DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); esp_ping_new_session(&ping_config, &cbs, &ping); DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); esp_ping_start(ping); DPRINTF("%s\t%d\n", __FUNCTION__,__LINE__); } ③、network.h #ifndef __NETWORK_H #define __NETWORK_H #include #include #include #include #include "sdkconfig.h" #include #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "freertos/event_groups.h" #include "freertos/queue.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 "lwip/err.h" #include "lwip/sockets.h" #include "lwip/inet.h" #include "lwip/ip4_addr.h" #include "lwip/sys.h" #include #include "esp_ping.h" #include "ping/ping_sock.h" #include "driver/gpio.h" #include #include #include #include // struct addrinfo #include //#define __DEBUG__ //宏定义调试打印开关 #ifdef __DEBUG__ #define DPRINTF(...) printf(__VA_ARGS__) //宏调试打印函数定义 #else #define DPRINTF(...) #endif #define WIFI_SSID "tony" #define WIFI_PASS "1008611123" #if defined(CONFIG_EXAMPLE_IPV4) #define HOST_IP_ADDR CONFIG_EXAMPLE_IPV4_ADDR #elif defined(CONFIG_EXAMPLE_IPV6) #define HOST_IP_ADDR CONFIG_EXAMPLE_IPV6_ADDR #else #define HOST_IP_ADDR "192.168.1.100" #endif #define PORT 6666 void connect_wifi_ap_event_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data); void device_connect_wifi_ap(uint8_t *wifi_ssid, uint8_t *wifi_passwd); int udp_client_init(void); int tcp_client_init(char ip_addr[]); void udp_client_task(void *pvParameters); void tcp_client_task(void *pvParameters); void key_udp_task(void *pvParameters); void key_tcp_task(void *pvParameters); int device_connect_to_server(char *target_ip); int device_scan_dest_server(char ip_addr[]); void ping_ip_success(esp_ping_handle_t handle, void *args); void ping_ip_timeout(esp_ping_handle_t handle, void *args); void ping_ip_end(esp_ping_handle_t handle, void *args); void device_ping_ip_addr(char *ip_str); extern esp_ping_handle_t ping; extern int ping_flag; extern int tcp_sock; extern int udp_sock; extern struct sockaddr_in dest_addr; #endif ④、完整工程源码     【免费】ESP32接入网络后，循环扫描服务器IP及端口是否在线的完整工程demo（ESP-IDF）资源-文库