NetworkInterface.cpp

/*
 * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#include "NetworkInterface.h"
#include "esp_netif.h"
#include "esp_netif_defaults.h"
#include "esp_system.h"
#include "lwip/ip_addr.h"
#include "lwip/err.h"
#include "lwip/netif.h"
#include "dhcpserver/dhcpserver.h"
#include "dhcpserver/dhcpserver_options.h"
#include "esp32-hal-log.h"

static NetworkInterface * _interfaces[ESP_NETIF_ID_MAX] = { NULL, NULL, NULL, NULL, NULL, NULL};
static esp_event_handler_instance_t _ip_ev_instance = NULL;

static NetworkInterface * getNetifByEspNetif(esp_netif_t *esp_netif){
    for (int i = 0; i < ESP_NETIF_ID_MAX; ++i){
        if(_interfaces[i] != NULL && _interfaces[i]->netif() == esp_netif){
            return _interfaces[i];
        }
    }
    return NULL;
}

NetworkInterface * getNetifByID(Network_Interface_ID id){
    if(id < ESP_NETIF_ID_MAX){
        return _interfaces[id];
    }
    return NULL;
}

static void _ip_event_cb(void* arg, esp_event_base_t event_base, int32_t event_id, void* event_data) {
    if (event_base == IP_EVENT){
        NetworkInterface * netif = NULL;
        if(event_id == IP_EVENT_STA_GOT_IP || event_id == IP_EVENT_ETH_GOT_IP || event_id == IP_EVENT_PPP_GOT_IP){
            ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
            netif = getNetifByEspNetif(event->esp_netif);
        } else if(event_id == IP_EVENT_STA_LOST_IP || event_id == IP_EVENT_PPP_LOST_IP || event_id == IP_EVENT_ETH_LOST_IP){
            ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
            netif = getNetifByEspNetif(event->esp_netif);
        } else if(event_id == IP_EVENT_GOT_IP6){
            ip_event_got_ip6_t* event = (ip_event_got_ip6_t*) event_data;
            netif = getNetifByEspNetif(event->esp_netif);
        } else if(event_id == IP_EVENT_AP_STAIPASSIGNED){
            ip_event_ap_staipassigned_t* event = (ip_event_ap_staipassigned_t*) event_data;
            netif = getNetifByEspNetif(event->esp_netif);
        }
        if(netif != NULL){
            netif->_onIpEvent(event_id, event_data);
        }
    }
}

void NetworkInterface::_onIpEvent(int32_t event_id, void* event_data){
    arduino_event_t arduino_event;
    arduino_event.event_id = ARDUINO_EVENT_MAX;
    if(event_id == _got_ip_event_id){
        setStatusBits(ESP_NETIF_HAS_IP_BIT);
#if ARDUHAL_LOG_LEVEL >= ARDUHAL_LOG_LEVEL_VERBOSE
        ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
        log_v("%s Got %sIP: " IPSTR " MASK: " IPSTR " GW: " IPSTR, desc(), event->ip_changed?"New ":"Same ", IP2STR(&event->ip_info.ip), IP2STR(&event->ip_info.netmask), IP2STR(&event->ip_info.gw));
#endif
        memcpy(&arduino_event.event_info.got_ip, event_data, sizeof(ip_event_got_ip_t));
#if SOC_WIFI_SUPPORTED
        if(_interface_id == ESP_NETIF_ID_STA){
            arduino_event.event_id = ARDUINO_EVENT_WIFI_STA_GOT_IP;
        } else
#endif
        // if(_interface_id == ESP_NETIF_ID_PPP){
        //     arduino_event.event_id = ARDUINO_EVENT_PPP_GOT_IP;
        // } else 
        if(_interface_id >= ESP_NETIF_ID_ETH && _interface_id < ESP_NETIF_ID_MAX){
            arduino_event.event_id = ARDUINO_EVENT_ETH_GOT_IP;
        }
    } else if(event_id == _lost_ip_event_id){
        clearStatusBits(ESP_NETIF_HAS_IP_BIT);
#if ARDUHAL_LOG_LEVEL >= ARDUHAL_LOG_LEVEL_VERBOSE
        log_v("%s Lost IP", desc());
#endif
#if SOC_WIFI_SUPPORTED
        if(_interface_id == ESP_NETIF_ID_STA){
            arduino_event.event_id = ARDUINO_EVENT_WIFI_STA_LOST_IP;
        } else 
#endif
        // if(_interface_id == ESP_NETIF_ID_PPP){
        //     arduino_event.event_id = ARDUINO_EVENT_PPP_LOST_IP;
        // } else 
        if(_interface_id >= ESP_NETIF_ID_ETH && _interface_id < ESP_NETIF_ID_MAX){
            arduino_event.event_id = ARDUINO_EVENT_ETH_LOST_IP;
        }
    } else if(event_id == IP_EVENT_GOT_IP6){
        ip_event_got_ip6_t* event = (ip_event_got_ip6_t*) event_data;
        esp_ip6_addr_type_t addr_type = esp_netif_ip6_get_addr_type(&event->ip6_info.ip);
        if(addr_type == ESP_IP6_ADDR_IS_GLOBAL){
            setStatusBits(ESP_NETIF_HAS_GLOBAL_IP6_BIT);
        } else if(addr_type == ESP_IP6_ADDR_IS_LINK_LOCAL){
            setStatusBits(ESP_NETIF_HAS_LOCAL_IP6_BIT);
        }
#if ARDUHAL_LOG_LEVEL >= ARDUHAL_LOG_LEVEL_VERBOSE        
        char if_name[NETIF_NAMESIZE] = {0,};
        netif_index_to_name(event->ip6_info.ip.zone, if_name);
        static const char * addr_types[] = { "UNKNOWN", "GLOBAL", "LINK_LOCAL", "SITE_LOCAL", "UNIQUE_LOCAL", "IPV4_MAPPED_IPV6" };
        log_v("IF %s Got IPv6: Interface: %d, IP Index: %d, Type: %s, Zone: %d (%s), Address: " IPV6STR, desc(), _interface_id, event->ip_index, addr_types[addr_type], event->ip6_info.ip.zone, if_name, IPV62STR(event->ip6_info.ip));
#endif
        memcpy(&arduino_event.event_info.got_ip6, event_data, sizeof(ip_event_got_ip6_t));
#if SOC_WIFI_SUPPORTED
        if(_interface_id == ESP_NETIF_ID_STA){
            arduino_event.event_id = ARDUINO_EVENT_WIFI_STA_GOT_IP6;
        } else if(_interface_id == ESP_NETIF_ID_AP){
            arduino_event.event_id = ARDUINO_EVENT_WIFI_AP_GOT_IP6;
        } else 
#endif
        // if(_interface_id == ESP_NETIF_ID_PPP){
        //     arduino_event.event_id = ARDUINO_EVENT_PPP_GOT_IP6;
        // } else 
        if(_interface_id >= ESP_NETIF_ID_ETH && _interface_id < ESP_NETIF_ID_MAX){
            arduino_event.event_id = ARDUINO_EVENT_ETH_GOT_IP6;
        }
#if SOC_WIFI_SUPPORTED
    } else if(event_id == IP_EVENT_AP_STAIPASSIGNED && _interface_id == ESP_NETIF_ID_AP){
        setStatusBits(ESP_NETIF_HAS_IP_BIT);
#if ARDUHAL_LOG_LEVEL >= ARDUHAL_LOG_LEVEL_VERBOSE
        ip_event_ap_staipassigned_t* event = (ip_event_ap_staipassigned_t*) event_data;
        log_v("%s Assigned IP: " IPSTR " to MAC: %02X:%02X:%02X:%02X:%02X:%02X", desc(), IP2STR(&event->ip), event->mac[0], event->mac[1], event->mac[2], event->mac[3], event->mac[4], event->mac[5]);
#endif
        arduino_event.event_id = ARDUINO_EVENT_WIFI_AP_STAIPASSIGNED;
        memcpy(&arduino_event.event_info.wifi_ap_staipassigned, event_data, sizeof(ip_event_ap_staipassigned_t));
#endif
    }
    
    if(arduino_event.event_id < ARDUINO_EVENT_MAX){
        Network.postEvent(&arduino_event);
    }
}

NetworkInterface::NetworkInterface()
    : _esp_netif(NULL)
    , _interface_event_group(NULL)
    , _initial_bits(0)
    , _got_ip_event_id(-1)
    , _lost_ip_event_id(-1)
    , _interface_id(ESP_NETIF_ID_MAX)
    , _is_server_if(false)
{}

NetworkInterface::~NetworkInterface(){
    destroyNetif();
}

IPAddress NetworkInterface::calculateNetworkID(IPAddress ip, IPAddress subnet) const {
	IPAddress networkID;

	for (size_t i = 0; i < 4; i++)
		networkID[i] = subnet[i] & ip[i];

	return networkID;
}

IPAddress NetworkInterface::calculateBroadcast(IPAddress ip, IPAddress subnet) const {
    IPAddress broadcastIp;
    
    for (int i = 0; i < 4; i++)
        broadcastIp[i] = ~subnet[i] | ip[i];

    return broadcastIp;
}

uint8_t NetworkInterface::calculateSubnetCIDR(IPAddress subnetMask) const {
	uint8_t CIDR = 0;

	for (uint8_t i = 0; i < 4; i++) {
		if (subnetMask[i] == 0x80)  // 128
			CIDR += 1;
		else if (subnetMask[i] == 0xC0)  // 192
			CIDR += 2;
		else if (subnetMask[i] == 0xE0)  // 224
			CIDR += 3;
		else if (subnetMask[i] == 0xF0)  // 242
			CIDR += 4;
		else if (subnetMask[i] == 0xF8)  // 248
			CIDR += 5;
		else if (subnetMask[i] == 0xFC)  // 252
			CIDR += 6;
		else if (subnetMask[i] == 0xFE)  // 254
			CIDR += 7;
		else if (subnetMask[i] == 0xFF)  // 255
			CIDR += 8;
	}

	return CIDR;
}

int NetworkInterface::setStatusBits(int bits) {
    if(!_interface_event_group){
        _initial_bits |= bits;
        return _initial_bits;
    }
    return xEventGroupSetBits(_interface_event_group, bits);
}

int NetworkInterface::clearStatusBits(int bits) {
    if(!_interface_event_group){
        _initial_bits &= ~bits;
        return _initial_bits;
    }
    return xEventGroupClearBits(_interface_event_group, bits) ;
}

int NetworkInterface::getStatusBits() const {
    if(!_interface_event_group){
        return _initial_bits;
    }
    return xEventGroupGetBits(_interface_event_group);
}

int NetworkInterface::waitStatusBits(int bits, uint32_t timeout_ms) const {
    if(!_interface_event_group){
        return 0;
    }
    bits = xEventGroupWaitBits(
        _interface_event_group, // The event group being tested.
        bits, // The bits within the event group to wait for.
        pdFALSE, // bits should be cleared before returning.
        pdTRUE, // Don't wait for all bits, any bit will do.
        timeout_ms / portTICK_PERIOD_MS ) & bits; // Wait a maximum of timeout_ms for any bit to be set.
    return bits;
}

void NetworkInterface::destroyNetif() {
    if(_ip_ev_instance != NULL){
        esp_event_handler_unregister(IP_EVENT, ESP_EVENT_ANY_ID, &_ip_event_cb);
        _ip_ev_instance = NULL;
    }
    if(_esp_netif != NULL){
        esp_netif_destroy(_esp_netif);
        _esp_netif = NULL;
    }
    if(_interface_event_group != NULL){
        vEventGroupDelete(_interface_event_group);
        _interface_event_group = NULL;
        _initial_bits = 0;
    }
}

bool NetworkInterface::initNetif(Network_Interface_ID interface_id, bool server_interface) {
    if(_esp_netif == NULL || interface_id >= ESP_NETIF_ID_MAX){
        return false;
    }
    _is_server_if = server_interface;
    _interface_id = interface_id;
    _got_ip_event_id = esp_netif_get_event_id(_esp_netif, ESP_NETIF_IP_EVENT_GOT_IP);
    _lost_ip_event_id = esp_netif_get_event_id(_esp_netif, ESP_NETIF_IP_EVENT_LOST_IP);
    _interfaces[_interface_id] = this;

    if(_interface_event_group == NULL){
        _interface_event_group = xEventGroupCreate();
        if(!_interface_event_group){
            log_e("Interface Event Group Create Failed!");
            return false;
        }
        setStatusBits(_initial_bits);
    }

    if(_ip_ev_instance == NULL && esp_event_handler_instance_register(IP_EVENT, ESP_EVENT_ANY_ID, &_ip_event_cb, NULL, &_ip_ev_instance)){
        log_e("event_handler_instance_register for IP_EVENT Failed!");
        return false;
    }
    return true;
}

bool NetworkInterface::started() const {
    return (getStatusBits() & ESP_NETIF_STARTED_BIT) != 0;
}

bool NetworkInterface::connected() const {
    return (getStatusBits() & ESP_NETIF_CONNECTED_BIT) != 0;
}

bool NetworkInterface::hasIP() const {
    return (getStatusBits() & (ESP_NETIF_HAS_IP_BIT | ESP_NETIF_HAS_STATIC_IP_BIT)) != 0;
}

bool NetworkInterface::hasLinkLocalIPv6() const {
    return (getStatusBits() & ESP_NETIF_HAS_LOCAL_IP6_BIT) != 0;
}

bool NetworkInterface::hasGlobalIPv6() const {
    return (getStatusBits() & ESP_NETIF_HAS_GLOBAL_IP6_BIT) != 0;
}

bool NetworkInterface::enableIPv6(bool en)
{
    if (en) {
        setStatusBits(ESP_NETIF_WANT_IP6_BIT);
    } else {
        clearStatusBits(ESP_NETIF_WANT_IP6_BIT);
    }
    return true;
}

bool NetworkInterface::dnsIP(uint8_t dns_no, IPAddress ip)
{
    if(_esp_netif == NULL || dns_no > 2){
        return false;
    }
    if(_is_server_if && dns_no > 0){
        log_e("Server interfaces can have only one DNS server.");
        return false;
    }
    esp_netif_dns_info_t d;
    // ToDo: can this work with IPv6 addresses?
    d.ip.type = IPADDR_TYPE_V4;
    if(static_cast<uint32_t>(ip) != 0){
        d.ip.u_addr.ip4.addr = static_cast<uint32_t>(ip);
    } else {
        d.ip.u_addr.ip4.addr = 0;
    }
    if(esp_netif_set_dns_info(_esp_netif, (esp_netif_dns_type_t)dns_no, &d) != ESP_OK){
        return false;
    }
    return true;
}

bool NetworkInterface::config(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dns1, IPAddress dns2, IPAddress dns3)
{
    if(_esp_netif == NULL){
        return false;
    }
    esp_err_t err = ESP_OK;
    esp_netif_ip_info_t info;
    esp_netif_dns_info_t d1;
    esp_netif_dns_info_t d2;
    esp_netif_dns_info_t d3;
    d1.ip.type = IPADDR_TYPE_V4;
    d2.ip.type = IPADDR_TYPE_V4;
    d3.ip.type = IPADDR_TYPE_V4;

    if(static_cast<uint32_t>(local_ip) != 0){
        info.ip.addr = static_cast<uint32_t>(local_ip);
        info.gw.addr = static_cast<uint32_t>(gateway);
        info.netmask.addr = static_cast<uint32_t>(subnet);
        d1.ip.u_addr.ip4.addr = static_cast<uint32_t>(dns1);
        d2.ip.u_addr.ip4.addr = static_cast<uint32_t>(dns2);
        d3.ip.u_addr.ip4.addr = static_cast<uint32_t>(dns3);
    } else {
        info.ip.addr = 0;
        info.gw.addr = 0;
        info.netmask.addr = 0;
        d1.ip.u_addr.ip4.addr = 0;
        d2.ip.u_addr.ip4.addr = 0;
        d3.ip.u_addr.ip4.addr = 0;
	}

    if(_is_server_if){
        // Stop DHCPS
        err = esp_netif_dhcps_stop(_esp_netif);
        if(err && err != ESP_ERR_ESP_NETIF_DHCP_ALREADY_STOPPED){
            log_e("DHCPS Stop Failed! 0x%04x: %s", err, esp_err_to_name(err));
            return false;
        }

        // Set IPv4, Netmask, Gateway
        err = esp_netif_set_ip_info(_esp_netif, &info);
        if(err){
            log_e("Netif Set IP Failed! 0x%04x: %s", err, esp_err_to_name(err));
            return false;
        }
        
        // Set DNS Server
        if(d2.ip.u_addr.ip4.addr != 0){
            esp_netif_set_dns_info(_esp_netif, ESP_NETIF_DNS_MAIN, &d2);
        }

        dhcps_lease_t lease;
        lease.enable = true;
        uint8_t CIDR = calculateSubnetCIDR(subnet);
        log_v("SoftAP: %s | Gateway: %s | DHCP Start: %s | Netmask: %s", local_ip.toString().c_str(), gateway.toString().c_str(), dns1.toString().c_str(), subnet.toString().c_str());
        // netmask must have room for at least 12 IP addresses (AP + GW + 10 DHCP Leasing addresses)
        // netmask also must be limited to the last 8 bits of IPv4, otherwise this function won't work
        // IDF NETIF checks netmask for the 3rd byte: https://github.com/espressif/esp-idf/blob/master/components/esp_netif/lwip/esp_netif_lwip.c#L1857-L1862
        if (CIDR > 28 || CIDR < 24) {
            log_e("Bad netmask. It must be from /24 to /28 (255.255.255. 0<->240)");
            return false; //  ESP_FAIL if initializing failed
        }
        #define _byte_swap32(num) (((num>>24)&0xff) | ((num<<8)&0xff0000) | ((num>>8)&0xff00) | ((num<<24)&0xff000000))
        // The code below is ready for any netmask, not limited to 255.255.255.0
        uint32_t netmask = _byte_swap32(info.netmask.addr);
        uint32_t ap_ipaddr = _byte_swap32(info.ip.addr);
        uint32_t dhcp_ipaddr = _byte_swap32(static_cast<uint32_t>(dns1));
        dhcp_ipaddr = dhcp_ipaddr == 0 ? ap_ipaddr + 1 : dhcp_ipaddr;
        uint32_t leaseStartMax = ~netmask - 10;
        // there will be 10 addresses for DHCP to lease
        lease.start_ip.addr = dhcp_ipaddr;
        lease.end_ip.addr = lease.start_ip.addr + 10;
        // Check if local_ip is in the same subnet as the dhcp leasing range initial address
        if ((ap_ipaddr & netmask) != (dhcp_ipaddr & netmask)) {
            log_e("The AP IP address (%s) and the DHCP start address (%s) must be in the same subnet", 
                local_ip.toString().c_str(), IPAddress(_byte_swap32(dhcp_ipaddr)).toString().c_str());
            return false; //  ESP_FAIL if initializing failed
        }
        // prevents DHCP lease range to overflow subnet range
        if ((dhcp_ipaddr & ~netmask) >= leaseStartMax) {
            // make first DHCP lease addr stay in the begining of the netmask range
            lease.start_ip.addr = (dhcp_ipaddr & netmask) + 1;
            lease.end_ip.addr = lease.start_ip.addr + 10;
            log_w("DHCP Lease out of range - Changing DHCP leasing start to %s", IPAddress(_byte_swap32(lease.start_ip.addr)).toString().c_str());
        }
        // Check if local_ip is within DHCP range
        if (ap_ipaddr >= lease.start_ip.addr && ap_ipaddr <= lease.end_ip.addr) {
            log_e("The AP IP address (%s) can't be within the DHCP range (%s -- %s)", 
                local_ip.toString().c_str(), IPAddress(_byte_swap32(lease.start_ip.addr)).toString().c_str(), IPAddress(_byte_swap32(lease.end_ip.addr)).toString().c_str());
            return false; //  ESP_FAIL if initializing failed
        }
        // Check if gateway is within DHCP range
        uint32_t gw_ipaddr = _byte_swap32(info.gw.addr);
        bool gw_in_same_subnet = (gw_ipaddr & netmask) == (ap_ipaddr & netmask);
        if (gw_in_same_subnet && gw_ipaddr >= lease.start_ip.addr && gw_ipaddr <= lease.end_ip.addr) {
            log_e("The GatewayP address (%s) can't be within the DHCP range (%s -- %s)", 
                gateway.toString().c_str(), IPAddress(_byte_swap32(lease.start_ip.addr)).toString().c_str(), IPAddress(_byte_swap32(lease.end_ip.addr)).toString().c_str());
            return false; //  ESP_FAIL if initializing failed
        }
        // all done, just revert back byte order of DHCP lease range
        lease.start_ip.addr = _byte_swap32(lease.start_ip.addr);
        lease.end_ip.addr = _byte_swap32(lease.end_ip.addr);
        log_v("DHCP Server Range: %s to %s", IPAddress(lease.start_ip.addr).toString().c_str(), IPAddress(lease.end_ip.addr).toString().c_str());
        err = esp_netif_dhcps_option(
            _esp_netif,
            ESP_NETIF_OP_SET,
            ESP_NETIF_REQUESTED_IP_ADDRESS,
            (void*)&lease, sizeof(dhcps_lease_t)
        );
        if(err){
            log_e("DHCPS Set Lease Failed! 0x%04x: %s", err, esp_err_to_name(err));
            return false;
        }
        // Start DHCPS
        err = esp_netif_dhcps_start(_esp_netif);
        if(err){
            log_e("DHCPS Start Failed! 0x%04x: %s", err, esp_err_to_name(err));
            return false;
        }
    } else {
        // Stop DHCPC
        err = esp_netif_dhcpc_stop(_esp_netif);
        if(err != ESP_OK && err != ESP_ERR_ESP_NETIF_DHCP_ALREADY_STOPPED){
            log_e("DHCP could not be stopped! Error: 0x%04x: %s", err, esp_err_to_name(err));
            return false;
        }

        clearStatusBits(ESP_NETIF_HAS_IP_BIT | ESP_NETIF_HAS_STATIC_IP_BIT);

        // Set IPv4, Netmask, Gateway
        err = esp_netif_set_ip_info(_esp_netif, &info);
        if(err != ERR_OK){
            log_e("ETH IP could not be configured! Error: 0x%04x: %s", err, esp_err_to_name(err));
            return false;
        }
        
        // Set DNS Servers
        esp_netif_set_dns_info(_esp_netif, ESP_NETIF_DNS_MAIN, &d1);
        esp_netif_set_dns_info(_esp_netif, ESP_NETIF_DNS_BACKUP, &d2);
        esp_netif_set_dns_info(_esp_netif, ESP_NETIF_DNS_FALLBACK, &d3);

        // Start DHCPC if static IP was set
        if(info.ip.addr == 0){
            err = esp_netif_dhcpc_start(_esp_netif);
            if(err != ESP_OK && err != ESP_ERR_ESP_NETIF_DHCP_ALREADY_STARTED){
                log_w("DHCP could not be started! Error: 0x%04x: %s", err, esp_err_to_name(err));
                return false;
            }
        } else {
            setStatusBits(ESP_NETIF_HAS_STATIC_IP_BIT);
        }
    }

    return true;
}

const char * NetworkInterface::getHostname() const
{
    if(_esp_netif == NULL){
        return "";
    }
    const char * hostname;
    if(esp_netif_get_hostname(_esp_netif, &hostname)){
        return NULL;
    }
    return hostname;
}

bool NetworkInterface::setHostname(const char * hostname) const
{
    if(_esp_netif == NULL){
        return false;
    }
    return esp_netif_set_hostname(_esp_netif, hostname) == 0;
}

bool NetworkInterface::linkUp() const
{
    if(_esp_netif == NULL){
        return false;
    }
    return esp_netif_is_netif_up(_esp_netif);
}

const char * NetworkInterface::ifkey(void) const
{
    if(_esp_netif == NULL){
        return "";
    }
    return esp_netif_get_ifkey(_esp_netif);
}

const char * NetworkInterface::desc(void) const
{
    if(_esp_netif == NULL){
        return "";
    }
    return esp_netif_get_desc(_esp_netif);
}

String NetworkInterface::impl_name(void) const
{
    if(_esp_netif == NULL){
        return String("");
    }
    char netif_name[8];
    esp_err_t err = esp_netif_get_netif_impl_name(_esp_netif, netif_name);
    if(err != ESP_OK){
        log_e("Failed to get netif impl_name: %d", err);
        return String("");
    }
    return String(netif_name);
}

uint8_t * NetworkInterface::macAddress(uint8_t* mac) const
{
    if(!mac || _esp_netif == NULL){
        return NULL;
    }
    esp_err_t err = esp_netif_get_mac(_esp_netif, mac);
    if(err != ESP_OK){
        log_e("Failed to get netif mac: %d", err);
        return NULL;
    }
    // getMac(mac);
    return mac;
}

String NetworkInterface::macAddress(void) const
{
    uint8_t mac[6] = {0,0,0,0,0,0};
    char macStr[18] = { 0 };
    macAddress(mac);
    sprintf(macStr, "%02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
    return String(macStr);
}

IPAddress NetworkInterface::localIP() const
{
    if(_esp_netif == NULL){
        return IPAddress();
    }
    esp_netif_ip_info_t ip;
    if(esp_netif_get_ip_info(_esp_netif, &ip)){
        return IPAddress();
    }
    return IPAddress(ip.ip.addr);
}

IPAddress NetworkInterface::subnetMask() const
{
    if(_esp_netif == NULL){
        return IPAddress();
    }
    esp_netif_ip_info_t ip;
    if(esp_netif_get_ip_info(_esp_netif, &ip)){
        return IPAddress();
    }
    return IPAddress(ip.netmask.addr);
}

IPAddress NetworkInterface::gatewayIP() const
{
    if(_esp_netif == NULL){
        return IPAddress();
    }
    esp_netif_ip_info_t ip;
    if(esp_netif_get_ip_info(_esp_netif, &ip)){
        return IPAddress();
    }
    return IPAddress(ip.gw.addr);
}

IPAddress NetworkInterface::dnsIP(uint8_t dns_no) const
{
    if(_esp_netif == NULL){
        return IPAddress();
    }
    esp_netif_dns_info_t d;
    if(esp_netif_get_dns_info(_esp_netif, dns_no?ESP_NETIF_DNS_BACKUP:ESP_NETIF_DNS_MAIN, &d) != ESP_OK){
        return IPAddress();
    }
    if (d.ip.type == ESP_IPADDR_TYPE_V6){
        // IPv6 from 4x uint32_t; byte order based on IPV62STR() in esp_netif_ip_addr.h
        log_d("DNS got IPv6: " IPV6STR, IPV62STR(d.ip.u_addr.ip6));
        uint32_t addr0 esp_netif_htonl(d.ip.u_addr.ip6.addr[0]);
        uint32_t addr1 esp_netif_htonl(d.ip.u_addr.ip6.addr[1]);
        uint32_t addr2 esp_netif_htonl(d.ip.u_addr.ip6.addr[2]);
        uint32_t addr3 esp_netif_htonl(d.ip.u_addr.ip6.addr[3]);
        return IPAddress(
            (uint8_t)(addr0 >> 24) & 0xFF,
            (uint8_t)(addr0 >> 16) & 0xFF,
            (uint8_t)(addr0 >> 8) & 0xFF,
            (uint8_t)addr0 & 0xFF,
            (uint8_t)(addr1 >> 24) & 0xFF,
            (uint8_t)(addr1 >> 16) & 0xFF,
            (uint8_t)(addr1 >> 8) & 0xFF,
            (uint8_t)addr1 & 0xFF,
            (uint8_t)(addr2 >> 24) & 0xFF,
            (uint8_t)(addr2 >> 16) & 0xFF,
            (uint8_t)(addr2 >> 8) & 0xFF,
            (uint8_t)addr2 & 0xFF,
            (uint8_t)(addr3 >> 24) & 0xFF,
            (uint8_t)(addr3 >> 16) & 0xFF,
            (uint8_t)(addr3 >> 8) & 0xFF,
            (uint8_t)addr3 & 0xFF,
            d.ip.u_addr.ip6.zone
        );
    }
    // IPv4 from single uint32_t
    log_d("DNS IPv4: " IPSTR, IP2STR(&d.ip.u_addr.ip4));
    return IPAddress(d.ip.u_addr.ip4.addr);
}

IPAddress NetworkInterface::broadcastIP() const
{
    if(_esp_netif == NULL){
        return IPAddress();
    }
    esp_netif_ip_info_t ip;
    if(esp_netif_get_ip_info(_esp_netif, &ip)){
        return IPAddress();
    }
    return calculateBroadcast(IPAddress(ip.gw.addr), IPAddress(ip.netmask.addr));
}

IPAddress NetworkInterface::networkID() const
{
    if(_esp_netif == NULL){
        return IPAddress();
    }
    esp_netif_ip_info_t ip;
    if(esp_netif_get_ip_info(_esp_netif, &ip)){
        return IPAddress();
    }
    return calculateNetworkID(IPAddress(ip.gw.addr), IPAddress(ip.netmask.addr));
}

uint8_t NetworkInterface::subnetCIDR() const
{
    if(_esp_netif == NULL){
        return (uint8_t)0;
    }
    esp_netif_ip_info_t ip;
    if(esp_netif_get_ip_info(_esp_netif, &ip)){
        return (uint8_t)0;
    }
    return calculateSubnetCIDR(IPAddress(ip.netmask.addr));
}

IPAddress NetworkInterface::linkLocalIPv6() const
{
    if(_esp_netif == NULL){
        return IPAddress(IPv6);
    }
    static esp_ip6_addr_t addr;
    if(esp_netif_get_ip6_linklocal(_esp_netif, &addr)){
        return IPAddress(IPv6);
    }
    return IPAddress(IPv6, (const uint8_t *)addr.addr, addr.zone);
}

IPAddress NetworkInterface::globalIPv6() const
{
    if(_esp_netif == NULL){
        return IPAddress(IPv6);
    }
    static esp_ip6_addr_t addr;
    if(esp_netif_get_ip6_global(_esp_netif, &addr)){
        return IPAddress(IPv6);
    }
    return IPAddress(IPv6, (const uint8_t *)addr.addr, addr.zone);
}

size_t NetworkInterface::printTo(Print & out) const {
    size_t bytes = 0;
    const char * dscr = esp_netif_get_desc(_esp_netif);
    if(dscr != NULL){
        bytes += out.print(dscr);
    }
    bytes += out.print(":");
    if(esp_netif_is_netif_up(_esp_netif)){
        bytes += out.print(" <UP");
    } else {
        bytes += out.print(" <DOWN");
    }
    bytes += printDriverInfo(out);
    bytes += out.println(">");

    bytes += out.print("      ");
    bytes += out.print("ether ");
    bytes += out.print(macAddress());
    bytes += out.println();

    bytes += out.print("      ");
    bytes += out.print("inet ");
    bytes += out.print(localIP());
    bytes += out.print(" netmask ");
    bytes += out.print(subnetMask());
    bytes += out.print(" broadcast ");
    bytes += out.print(broadcastIP());
    bytes += out.println();

    bytes += out.print("      ");
    bytes += out.print("gateway ");
    bytes += out.print(gatewayIP());
    bytes += out.print(" dns ");
    bytes += out.print(dnsIP());
    bytes += out.println();

    static const char * types[] = { "UNKNOWN", "GLOBAL", "LINK_LOCAL", "SITE_LOCAL", "UNIQUE_LOCAL", "IPV4_MAPPED_IPV6" };
    esp_ip6_addr_t if_ip6[CONFIG_LWIP_IPV6_NUM_ADDRESSES];
    int v6addrs = esp_netif_get_all_ip6(_esp_netif, if_ip6);
    for (int i = 0; i < v6addrs; ++i){
        bytes += out.print("      ");
        bytes += out.print("inet6 ");
        bytes += IPAddress(IPv6, (const uint8_t *)if_ip6[i].addr, if_ip6[i].zone).printTo(out, true);
        bytes += out.print(" type ");
        bytes += out.print(types[esp_netif_ip6_get_addr_type(&if_ip6[i])]);
        bytes += out.println();
    }

    return bytes;
}