[ESP32][esp-idf] AP+STA实现无线桥接 中转wifi信号

引言：无线中继的主要作用是扩展WiFi信号，扩展WiFi后，令原本覆盖不到WiFi的地方也可以有WiFi，免去布线的烦恼。两个无线路由器桥接到一起，可以实现WiFi信号全覆盖。

实现的功能：WiFi模块能连接路由器，然后手机能连接WiFi模块，然后手机通过WiFi模块连接到路由器，能通过WiFi模块上网。

配置宏

# Set up wifi hotspot and share network

CONFIG_LWIP_IP_FORWARD=y

CONFIG_LWIP_IPV4_NAPT=y

demo.c代码如下：

#include

#include

#include "esp_event.h"

#include "esp_log.h"

#include "esp_system.h"

#include "nvs_flash.h"

#include "esp_wifi.h"

#include "esp_netif.h"

#include "lwip/inet.h"

#include "lwip/lwip_napt.h"

// 热点名称 密码  可连接数量

#define AP_WIFI_SSID "lisun"

#define AP_WIFI_PASS "xjq12345"

#define AP_MAX_STA_CONN 4

// 路由器wifi名称 密码

#define STA_WIFI_SSID "xjq"

#define STA_WIFI_PASS "xjq12345"

static const char *TAG = "LiSun";

static esp_netif_t* _esp_netif_sta = NULL;

static esp_netif_t* _esp_netif_ap = NULL;

static void wifi_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data) {

if (event_id == WIFI_EVENT_AP_STACONNECTED) {

wifi_event_ap_staconnected_t *event = (wifi_event_ap_staconnected_t *)event_data;

ESP_LOGI(TAG, "station " MACSTR " join, AID=%d",

MAC2STR(event->mac), event->aid);

} else if (event_id == WIFI_EVENT_AP_STADISCONNECTED) {

wifi_event_ap_stadisconnected_t *event = (wifi_event_ap_stadisconnected_t *)event_data;

ESP_LOGI(TAG, "station " MACSTR " leave, AID=%d",

MAC2STR(event->mac), event->aid);

}

}

static void sta_start_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data) {

esp_wifi_connect();

}

static void got_ip_handler(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data) {

//No need to log, wifi driver logs automatically

esp_netif_dns_info_t dns;

if (esp_netif_get_dns_info(_esp_netif_sta, ESP_NETIF_DNS_MAIN, &dns) == ESP_OK) {

dhcps_dns_setserver((const ip_addr_t *)&dns.ip);

ESP_LOGI(TAG, "set dns to:" IPSTR, IP2STR(&dns.ip.u_addr.ip4));

}

}

static void wifi_init_softap(void)

{

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, &wifi_event_handler, NULL));

wifi_config_t wifi_config = {

.ap = {

.ssid = AP_WIFI_SSID,

.ssid_len = strlen(AP_WIFI_SSID),

.password = AP_WIFI_PASS,

.max_connection = AP_MAX_STA_CONN,

.authmode = WIFI_AUTH_WPA_WPA2_PSK

},

};

if (strlen(AP_WIFI_PASS) == 0)

wifi_config.ap.authmode = WIFI_AUTH_OPEN;

ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_APSTA));

ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_AP, &wifi_config));

wifi_config_t cfg1 = {

.sta = {

.ssid = STA_WIFI_SSID,

.password = STA_WIFI_PASS,

.threshold = {.rssi=0, .authmode = WIFI_AUTH_WPA2_PSK},

.pmf_cfg = {

.capable = true,

.required = false

},

},

};

ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &cfg1));

ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, WIFI_EVENT_STA_START, sta_start_handler, NULL));

ESP_ERROR_CHECK(esp_wifi_start());

esp_netif_ip_info_t ip_info;

esp_netif_get_ip_info(esp_netif_get_handle_from_ifkey("WIFI_AP_DEF"), &ip_info);

char ip_addr[16];

inet_ntoa_r(ip_info.ip.addr, ip_addr, 16);

ESP_LOGI(TAG, "Set up softAP with IP: %s", ip_addr);

ESP_LOGI(TAG, "wifi_init_softap finished. SSID:'%s' password:'%s'", AP_WIFI_SSID, AP_WIFI_PASS);

}

void app_main(void)

{

// Initialize networking stack

ESP_ERROR_CHECK(esp_netif_init());

// Create default event loop needed by the  main app

ESP_ERROR_CHECK(esp_event_loop_create_default());

// Initialize NVS needed by Wi-Fi

ESP_ERROR_CHECK(nvs_flash_init());

// Initialize Wi-Fi including netif with default config

_esp_netif_ap = esp_netif_create_default_wifi_ap();

_esp_netif_sta = esp_netif_create_default_wifi_sta();

// Initialise ESP32 in SoftAP mode

wifi_init_softap();

ip_addr_t dnsserver;

// Enable DNS (offer) for dhcp server

dhcps_offer_t dhcps_dns_value = OFFER_DNS;

dhcps_set_option_info(6, &dhcps_dns_value, sizeof(dhcps_dns_value));

// Set custom dns server address for dhcp server 默认跟随路由器 【推荐换成国内DNS】

dnsserver.u_addr.ip4.addr = htonl(0xC0A80301);

dnsserver.type = IPADDR_TYPE_V4;

dhcps_dns_setserver(&dnsserver);

#if IP_NAPT

// !!! 必须启动sta后再设置，不然ap无网络 !!! Set to ip address of softAP netif (Default is 192.168.4.1)

u32_t napt_netif_ip = 0xC0A80401;

ip_napt_enable(htonl(napt_netif_ip), 1);

#endif

}