text: /* Common functions for protocol examples, to establish Wi-Fi or Ethernet connection.
  
     This example code is in the Public Domain (or CC0 licensed, at your option.)
  
     Unless required by applicable law or agreed to in writing, this
     software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
     CONDITIONS OF ANY KIND, either express or implied.
   */
  
  #include <string.h>
  #include "protocol_examples_common.h"
  #include "sdkconfig.h"
  #include "esp_event.h"
  #include "esp_wifi.h"
  #include "esp_wifi_default.h"
  #if CONFIG_EXAMPLE_CONNECT_ETHERNET
  #include "esp_eth.h"
  #if CONFIG_ETH_USE_SPI_ETHERNET
  #include "driver/spi_master.h"
  #endif // CONFIG_ETH_USE_SPI_ETHERNET
  #endif // CONFIG_EXAMPLE_CONNECT_ETHERNET
  #include "esp_log.h"
  #include "esp_netif.h"
  #include "driver/gpio.h"
  #include "freertos/FreeRTOS.h"
  #include "freertos/task.h"
  #include "freertos/event_groups.h"
  #include "lwip/err.h"
  #include "lwip/sys.h"
  
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
  #define MAX_IP6_ADDRS_PER_NETIF (5)
  #define NR_OF_IP_ADDRESSES_TO_WAIT_FOR (s_active_interfaces*2)
  
  #if defined(CONFIG_EXAMPLE_CONNECT_IPV6_PREF_LOCAL_LINK)
  #define EXAMPLE_CONNECT_PREFERRED_IPV6_TYPE ESP_IP6_ADDR_IS_LINK_LOCAL
  #elif defined(CONFIG_EXAMPLE_CONNECT_IPV6_PREF_GLOBAL)
  #define EXAMPLE_CONNECT_PREFERRED_IPV6_TYPE ESP_IP6_ADDR_IS_GLOBAL
  #elif defined(CONFIG_EXAMPLE_CONNECT_IPV6_PREF_SITE_LOCAL)
  #define EXAMPLE_CONNECT_PREFERRED_IPV6_TYPE ESP_IP6_ADDR_IS_SITE_LOCAL
  #elif defined(CONFIG_EXAMPLE_CONNECT_IPV6_PREF_UNIQUE_LOCAL)
  #define EXAMPLE_CONNECT_PREFERRED_IPV6_TYPE ESP_IP6_ADDR_IS_UNIQUE_LOCAL
  #endif // if-elif CONFIG_EXAMPLE_CONNECT_IPV6_PREF_...
  
  #else
  #define NR_OF_IP_ADDRESSES_TO_WAIT_FOR (s_active_interfaces)
  #endif
  
  #define EXAMPLE_DO_CONNECT CONFIG_EXAMPLE_CONNECT_WIFI || CONFIG_EXAMPLE_CONNECT_ETHERNET
  
  #if CONFIG_EXAMPLE_WIFI_SCAN_METHOD_FAST
  #define EXAMPLE_WIFI_SCAN_METHOD WIFI_FAST_SCAN
  #elif CONFIG_EXAMPLE_WIFI_SCAN_METHOD_ALL_CHANNEL
  #define EXAMPLE_WIFI_SCAN_METHOD WIFI_ALL_CHANNEL_SCAN
  #endif
  
  #if CONFIG_EXAMPLE_WIFI_CONNECT_AP_BY_SIGNAL
  #define EXAMPLE_WIFI_CONNECT_AP_SORT_METHOD WIFI_CONNECT_AP_BY_SIGNAL
  #elif CONFIG_EXAMPLE_WIFI_CONNECT_AP_BY_SECURITY
  #define EXAMPLE_WIFI_CONNECT_AP_SORT_METHOD WIFI_CONNECT_AP_BY_SECURITY
  #endif
  
  #if CONFIG_EXAMPLE_WIFI_AUTH_OPEN
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_OPEN
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WEP
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WEP
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WPA_PSK
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA_PSK
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WPA2_PSK
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA2_PSK
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WPA_WPA2_PSK
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA_WPA2_PSK
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WPA2_ENTERPRISE
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA2_ENTERPRISE
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WPA3_PSK
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA3_PSK
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WPA2_WPA3_PSK
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WPA2_WPA3_PSK
  #elif CONFIG_EXAMPLE_WIFI_AUTH_WAPI_PSK
  #define EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD WIFI_AUTH_WAPI_PSK
  #endif
  
  static int s_active_interfaces = 0;
  static xSemaphoreHandle s_semph_get_ip_addrs;
  static esp_netif_t *s_example_esp_netif = NULL;
  
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
  static esp_ip6_addr_t s_ipv6_addr;
  
  /* types of ipv6 addresses to be displayed on ipv6 events */
  static const char *s_ipv6_addr_types[] = {
      "ESP_IP6_ADDR_IS_UNKNOWN",
      "ESP_IP6_ADDR_IS_GLOBAL",
      "ESP_IP6_ADDR_IS_LINK_LOCAL",
      "ESP_IP6_ADDR_IS_SITE_LOCAL",
      "ESP_IP6_ADDR_IS_UNIQUE_LOCAL",
      "ESP_IP6_ADDR_IS_IPV4_MAPPED_IPV6"
  };
  #endif
  
  static const char *TAG = "example_connect";
  
  #if CONFIG_EXAMPLE_CONNECT_WIFI
  static esp_netif_t *wifi_start(void);
  static void wifi_stop(void);
  #endif
  #if CONFIG_EXAMPLE_CONNECT_ETHERNET
  static esp_netif_t *eth_start(void);
  static void eth_stop(void);
  #endif
  
  /**
   * @brief Checks the netif description if it contains specified prefix.
   * All netifs created withing common connect component are prefixed with the module TAG,
   * so it returns true if the specified netif is owned by this module
   */
  static bool is_our_netif(const char *prefix, esp_netif_t *netif)
  {
      return strncmp(prefix, esp_netif_get_desc(netif), strlen(prefix) - 1) == 0;
  }
  
  /* set up connection, Wi-Fi and/or Ethernet */
  static void start(void)
  {
  
  #if CONFIG_EXAMPLE_CONNECT_WIFI
      s_example_esp_netif = wifi_start();
      s_active_interfaces++;
  #endif
  
  #if CONFIG_EXAMPLE_CONNECT_ETHERNET
      s_example_esp_netif = eth_start();
      s_active_interfaces++;
  #endif
  
  #if CONFIG_EXAMPLE_CONNECT_WIFI && CONFIG_EXAMPLE_CONNECT_ETHERNET
      /* if both intefaces at once, clear out to indicate that multiple netifs are active */
      s_example_esp_netif = NULL;
  #endif
  
  #if EXAMPLE_DO_CONNECT
      /* create semaphore if at least one interface is active */
      s_semph_get_ip_addrs = xSemaphoreCreateCounting(NR_OF_IP_ADDRESSES_TO_WAIT_FOR, 0);
  #endif
  
  }
  
  /* tear down connection, release resources */
  static void stop(void)
  {
  #if CONFIG_EXAMPLE_CONNECT_WIFI
      wifi_stop();
      s_active_interfaces--;
  #endif
  
  #if CONFIG_EXAMPLE_CONNECT_ETHERNET
      eth_stop();
      s_active_interfaces--;
  #endif
  }
  
  #if EXAMPLE_DO_CONNECT
  static esp_ip4_addr_t s_ip_addr;
  
  static void on_got_ip(void *arg, esp_event_base_t event_base,
                        int32_t event_id, void *event_data)
  {
      ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
      if (!is_our_netif(TAG, event->esp_netif)) {
          ESP_LOGW(TAG, "Got IPv4 from another interface \"%s\": ignored", esp_netif_get_desc(event->esp_netif));
          return;
      }
      ESP_LOGI(TAG, "Got IPv4 event: Interface \"%s\" address: " IPSTR, esp_netif_get_desc(event->esp_netif), IP2STR(&event->ip_info.ip));
      memcpy(&s_ip_addr, &event->ip_info.ip, sizeof(s_ip_addr));
      xSemaphoreGive(s_semph_get_ip_addrs);
  }
  #endif
  
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
  
  static void on_got_ipv6(void *arg, esp_event_base_t event_base,
                          int32_t event_id, void *event_data)
  {
      ip_event_got_ip6_t *event = (ip_event_got_ip6_t *)event_data;
      if (!is_our_netif(TAG, event->esp_netif)) {
          ESP_LOGW(TAG, "Got IPv6 from another netif: ignored");
          return;
      }
      esp_ip6_addr_type_t ipv6_type = esp_netif_ip6_get_addr_type(&event->ip6_info.ip);
      ESP_LOGI(TAG, "Got IPv6 event: Interface \"%s\" address: " IPV6STR ", type: %s", esp_netif_get_desc(event->esp_netif),
               IPV62STR(event->ip6_info.ip), s_ipv6_addr_types[ipv6_type]);
      if (ipv6_type == EXAMPLE_CONNECT_PREFERRED_IPV6_TYPE) {
          memcpy(&s_ipv6_addr, &event->ip6_info.ip, sizeof(s_ipv6_addr));
          xSemaphoreGive(s_semph_get_ip_addrs);
      }
  }
  
  #endif // CONFIG_EXAMPLE_CONNECT_IPV6
  
  esp_err_t example_connect(void)
  {
  #if EXAMPLE_DO_CONNECT
      if (s_semph_get_ip_addrs != NULL) {
          return ESP_ERR_INVALID_STATE;
      }
  #endif
      start();
      ESP_ERROR_CHECK(esp_register_shutdown_handler(&stop));
      ESP_LOGI(TAG, "Waiting for IP(s)");
      for (int i = 0; i < NR_OF_IP_ADDRESSES_TO_WAIT_FOR; ++i) {
          xSemaphoreTake(s_semph_get_ip_addrs, portMAX_DELAY);
      }
      // iterate over active interfaces, and print out IPs of "our" netifs
      esp_netif_t *netif = NULL;
      esp_netif_ip_info_t ip;
      for (int i = 0; i < esp_netif_get_nr_of_ifs(); ++i) {
          netif = esp_netif_next(netif);
          if (is_our_netif(TAG, netif)) {
              ESP_LOGI(TAG, "Connected to %s", esp_netif_get_desc(netif));
              ESP_ERROR_CHECK(esp_netif_get_ip_info(netif, &ip));
  
              ESP_LOGI(TAG, "- IPv4 address: " IPSTR, IP2STR(&ip.ip));
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
              esp_ip6_addr_t ip6[MAX_IP6_ADDRS_PER_NETIF];
              int ip6_addrs = esp_netif_get_all_ip6(netif, ip6);
              for (int j = 0; j < ip6_addrs; ++j) {
                  esp_ip6_addr_type_t ipv6_type = esp_netif_ip6_get_addr_type(&(ip6[j]));
                  ESP_LOGI(TAG, "- IPv6 address: " IPV6STR ", type: %s", IPV62STR(ip6[j]), s_ipv6_addr_types[ipv6_type]);
              }
  #endif
  
          }
      }
      return ESP_OK;
  }
  
  esp_err_t example_disconnect(void)
  {
      if (s_semph_get_ip_addrs == NULL) {
          return ESP_ERR_INVALID_STATE;
      }
      vSemaphoreDelete(s_semph_get_ip_addrs);
      s_semph_get_ip_addrs = NULL;
      stop();
      ESP_ERROR_CHECK(esp_unregister_shutdown_handler(&stop));
      return ESP_OK;
  }
  
  #ifdef CONFIG_EXAMPLE_CONNECT_WIFI
  
  static void on_wifi_disconnect(void *arg, esp_event_base_t event_base,
                                 int32_t event_id, void *event_data)
  {
      ESP_LOGI(TAG, "Wi-Fi disconnected, trying to reconnect...");
      esp_err_t err = esp_wifi_connect();
      if (err == ESP_ERR_WIFI_NOT_STARTED) {
          return;
      }
      ESP_ERROR_CHECK(err);
  }
  
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
  
  static void on_wifi_connect(void *esp_netif, esp_event_base_t event_base,
                              int32_t event_id, void *event_data)
  {
      esp_netif_create_ip6_linklocal(esp_netif);
  }
  
  #endif // CONFIG_EXAMPLE_CONNECT_IPV6
  
  static esp_netif_t *wifi_start(void)
  {
      char *desc;
      wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
      ESP_ERROR_CHECK(esp_wifi_init(&cfg));
  
      esp_netif_inherent_config_t esp_netif_config = ESP_NETIF_INHERENT_DEFAULT_WIFI_STA();
      // Prefix the interface description with the module TAG
      // Warning: the interface desc is used in tests to capture actual connection details (IP, gw, mask)
      asprintf(&desc, "%s: %s", TAG, esp_netif_config.if_desc);
      esp_netif_config.if_desc = desc;
      esp_netif_config.route_prio = 128;
      esp_netif_t *netif = esp_netif_create_wifi(WIFI_IF_STA, &esp_netif_config);
      free(desc);
      esp_wifi_set_default_wifi_sta_handlers();
  
      ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, WIFI_EVENT_STA_DISCONNECTED, &on_wifi_disconnect, NULL));
      ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &on_got_ip, NULL));
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
      ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, WIFI_EVENT_STA_CONNECTED, &on_wifi_connect, netif));
      ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_GOT_IP6, &on_got_ipv6, NULL));
  #endif
  
      ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
      wifi_config_t wifi_config = {
          .sta = {
              .ssid = CONFIG_EXAMPLE_WIFI_SSID,
              .password = CONFIG_EXAMPLE_WIFI_PASSWORD,
              .scan_method = EXAMPLE_WIFI_SCAN_METHOD,
              .sort_method = EXAMPLE_WIFI_CONNECT_AP_SORT_METHOD,
              .threshold.rssi = CONFIG_EXAMPLE_WIFI_SCAN_RSSI_THRESHOLD,
              .threshold.authmode = EXAMPLE_WIFI_SCAN_AUTH_MODE_THRESHOLD,
          },
      };
      ESP_LOGI(TAG, "Connecting to %s...", wifi_config.sta.ssid);
      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_wifi_connect();
      return netif;
  }
  
  static void wifi_stop(void)
  {
      esp_netif_t *wifi_netif = get_example_netif_from_desc("sta");
      ESP_ERROR_CHECK(esp_event_handler_unregister(WIFI_EVENT, WIFI_EVENT_STA_DISCONNECTED, &on_wifi_disconnect));
      ESP_ERROR_CHECK(esp_event_handler_unregister(IP_EVENT, IP_EVENT_STA_GOT_IP, &on_got_ip));
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
      ESP_ERROR_CHECK(esp_event_handler_unregister(IP_EVENT, IP_EVENT_GOT_IP6, &on_got_ipv6));
      ESP_ERROR_CHECK(esp_event_handler_unregister(WIFI_EVENT, WIFI_EVENT_STA_CONNECTED, &on_wifi_connect));
  #endif
      esp_err_t err = esp_wifi_stop();
      if (err == ESP_ERR_WIFI_NOT_INIT) {
          return;
      }
      ESP_ERROR_CHECK(err);
      ESP_ERROR_CHECK(esp_wifi_deinit());
      ESP_ERROR_CHECK(esp_wifi_clear_default_wifi_driver_and_handlers(wifi_netif));
      esp_netif_destroy(wifi_netif);
      s_example_esp_netif = NULL;
  }
  #endif // CONFIG_EXAMPLE_CONNECT_WIFI
  
  #ifdef CONFIG_EXAMPLE_CONNECT_ETHERNET
  
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
  
  /** Event handler for Ethernet events */
  static void on_eth_event(void *esp_netif, esp_event_base_t event_base,
                           int32_t event_id, void *event_data)
  {
      switch (event_id) {
      case ETHERNET_EVENT_CONNECTED:
          ESP_LOGI(TAG, "Ethernet Link Up");
          ESP_ERROR_CHECK(esp_netif_create_ip6_linklocal(esp_netif));
          break;
      default:
          break;
      }
  }
  
  #endif // CONFIG_EXAMPLE_CONNECT_IPV6
  
  static esp_eth_handle_t s_eth_handle = NULL;
  static esp_eth_mac_t *s_mac = NULL;
  static esp_eth_phy_t *s_phy = NULL;
  static esp_eth_netif_glue_handle_t s_eth_glue = NULL;
  
  static esp_netif_t *eth_start(void)
  {
      char *desc;
      esp_netif_inherent_config_t esp_netif_config = ESP_NETIF_INHERENT_DEFAULT_ETH();
      // Prefix the interface description with the module TAG
      // Warning: the interface desc is used in tests to capture actual connection details (IP, gw, mask)
      asprintf(&desc, "%s: %s", TAG, esp_netif_config.if_desc);
      esp_netif_config.if_desc = desc;
      esp_netif_config.route_prio = 64;
      esp_netif_config_t netif_config = {
          .base = &esp_netif_config,
          .stack = ESP_NETIF_NETSTACK_DEFAULT_ETH
      };
      esp_netif_t *netif = esp_netif_new(&netif_config);
      assert(netif);
      free(desc);
  
      eth_mac_config_t mac_config = ETH_MAC_DEFAULT_CONFIG();
      eth_phy_config_t phy_config = ETH_PHY_DEFAULT_CONFIG();
      phy_config.phy_addr = CONFIG_EXAMPLE_ETH_PHY_ADDR;
      phy_config.reset_gpio_num = CONFIG_EXAMPLE_ETH_PHY_RST_GPIO;
  #if CONFIG_EXAMPLE_USE_INTERNAL_ETHERNET
      mac_config.smi_mdc_gpio_num = CONFIG_EXAMPLE_ETH_MDC_GPIO;
      mac_config.smi_mdio_gpio_num = CONFIG_EXAMPLE_ETH_MDIO_GPIO;
      s_mac = esp_eth_mac_new_esp32(&mac_config);
  #if CONFIG_EXAMPLE_ETH_PHY_IP101
      s_phy = esp_eth_phy_new_ip101(&phy_config);
  #elif CONFIG_EXAMPLE_ETH_PHY_RTL8201
      s_phy = esp_eth_phy_new_rtl8201(&phy_config);
  #elif CONFIG_EXAMPLE_ETH_PHY_LAN87XX
      s_phy = esp_eth_phy_new_lan87xx(&phy_config);
  #elif CONFIG_EXAMPLE_ETH_PHY_DP83848
      s_phy = esp_eth_phy_new_dp83848(&phy_config);
  #endif
  #elif CONFIG_EXAMPLE_USE_SPI_ETHERNET
      gpio_install_isr_service(0);
      spi_device_handle_t spi_handle = NULL;
      spi_bus_config_t buscfg = {
          .miso_io_num = CONFIG_EXAMPLE_ETH_SPI_MISO_GPIO,
          .mosi_io_num = CONFIG_EXAMPLE_ETH_SPI_MOSI_GPIO,
          .sclk_io_num = CONFIG_EXAMPLE_ETH_SPI_SCLK_GPIO,
          .quadwp_io_num = -1,
          .quadhd_io_num = -1,
      };
      ESP_ERROR_CHECK(spi_bus_initialize(CONFIG_EXAMPLE_ETH_SPI_HOST, &buscfg, 1));
  #if CONFIG_EXAMPLE_USE_DM9051
      spi_device_interface_config_t devcfg = {
          .command_bits = 1,
          .address_bits = 7,
          .mode = 0,
          .clock_speed_hz = CONFIG_EXAMPLE_ETH_SPI_CLOCK_MHZ * 1000 * 1000,
          .spics_io_num = CONFIG_EXAMPLE_ETH_SPI_CS_GPIO,
          .queue_size = 20
      };
      ESP_ERROR_CHECK(spi_bus_add_device(CONFIG_EXAMPLE_ETH_SPI_HOST, &devcfg, &spi_handle));
      /* dm9051 ethernet driver is based on spi driver */
      eth_dm9051_config_t dm9051_config = ETH_DM9051_DEFAULT_CONFIG(spi_handle);
      dm9051_config.int_gpio_num = CONFIG_EXAMPLE_ETH_SPI_INT_GPIO;
      s_mac = esp_eth_mac_new_dm9051(&dm9051_config, &mac_config);
      s_phy = esp_eth_phy_new_dm9051(&phy_config);
  #elif CONFIG_EXAMPLE_USE_W5500
      spi_device_interface_config_t devcfg = {
          .command_bits = 16, // Actually it's the address phase in W5500 SPI frame
          .address_bits = 8,  // Actually it's the control phase in W5500 SPI frame
          .mode = 0,
          .clock_speed_hz = CONFIG_EXAMPLE_ETH_SPI_CLOCK_MHZ * 1000 * 1000,
          .spics_io_num = CONFIG_EXAMPLE_ETH_SPI_CS_GPIO,
          .queue_size = 20
      };
      ESP_ERROR_CHECK(spi_bus_add_device(CONFIG_EXAMPLE_ETH_SPI_HOST, &devcfg, &spi_handle));
      /* w5500 ethernet driver is based on spi driver */
      eth_w5500_config_t w5500_config = ETH_W5500_DEFAULT_CONFIG(spi_handle);
      w5500_config.int_gpio_num = CONFIG_EXAMPLE_ETH_SPI_INT_GPIO;
      s_mac = esp_eth_mac_new_w5500(&w5500_config, &mac_config);
      s_phy = esp_eth_phy_new_w5500(&phy_config);
  #endif
  #elif CONFIG_EXAMPLE_USE_OPENETH
      phy_config.autonego_timeout_ms = 100;
      s_mac = esp_eth_mac_new_openeth(&mac_config);
      s_phy = esp_eth_phy_new_dp83848(&phy_config);
  #endif
  
      // Install Ethernet driver
      esp_eth_config_t config = ETH_DEFAULT_CONFIG(s_mac, s_phy);
      ESP_ERROR_CHECK(esp_eth_driver_install(&config, &s_eth_handle));
  #if !CONFIG_EXAMPLE_USE_INTERNAL_ETHERNET
      /* The SPI Ethernet module might doesn't have a burned factory MAC address, we cat to set it manually.
         02:00:00 is a Locally Administered OUI range so should not be used except when testing on a LAN under your control.
      */
      ESP_ERROR_CHECK(esp_eth_ioctl(s_eth_handle, ETH_CMD_S_MAC_ADDR, (uint8_t[]) {
          0x02, 0x00, 0x00, 0x12, 0x34, 0x56
      }));
  #endif
      // combine driver with netif
      s_eth_glue = esp_eth_new_netif_glue(s_eth_handle);
      esp_netif_attach(netif, s_eth_glue);
  
      // Register user defined event handers
      ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_ETH_GOT_IP, &on_got_ip, NULL));
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
      ESP_ERROR_CHECK(esp_event_handler_register(ETH_EVENT, ETHERNET_EVENT_CONNECTED, &on_eth_event, netif));
      ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_GOT_IP6, &on_got_ipv6, NULL));
  #endif
  
      esp_eth_start(s_eth_handle);
      return netif;
  }
  
  static void eth_stop(void)
  {
      esp_netif_t *eth_netif = get_example_netif_from_desc("eth");
      ESP_ERROR_CHECK(esp_event_handler_unregister(IP_EVENT, IP_EVENT_ETH_GOT_IP, &on_got_ip));
  #ifdef CONFIG_EXAMPLE_CONNECT_IPV6
      ESP_ERROR_CHECK(esp_event_handler_unregister(IP_EVENT, IP_EVENT_GOT_IP6, &on_got_ipv6));
      ESP_ERROR_CHECK(esp_event_handler_unregister(ETH_EVENT, ETHERNET_EVENT_CONNECTED, &on_eth_event));
  #endif
      ESP_ERROR_CHECK(esp_eth_stop(s_eth_handle));
      ESP_ERROR_CHECK(esp_eth_del_netif_glue(s_eth_glue));
      ESP_ERROR_CHECK(esp_eth_driver_uninstall(s_eth_handle));
      ESP_ERROR_CHECK(s_phy->del(s_phy));
      ESP_ERROR_CHECK(s_mac->del(s_mac));
  
      esp_netif_destroy(eth_netif);
      s_example_esp_netif = NULL;
  }
  
  #endif // CONFIG_EXAMPLE_CONNECT_ETHERNET
  
  esp_netif_t *get_example_netif(void)
  {
      return s_example_esp_netif;
  }
  
  esp_netif_t *get_example_netif_from_desc(const char *desc)
  {
      esp_netif_t *netif = NULL;
      char *expected_desc;
      asprintf(&expected_desc, "%s: %s", TAG, desc);
      while ((netif = esp_netif_next(netif)) != NULL) {
          if (strcmp(esp_netif_get_desc(netif), expected_desc) == 0) {
              free(expected_desc);
              return netif;
          }
      }
      free(expected_desc);
      return netif;
  }
  