Register Ethernet netif in WiFiGeneric to

[s-hadinger]

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Description of Change

Register the ethernet netif object in WiFiGeneric esp_netifs. Without this registry, IP6 events are never sent back to event callback, because of the tests here:

arduino-esp32/libraries/WiFi/src/WiFiGeneric.cpp

Lines 453 to 464 in b63f947

	} else if (event_base == IP_EVENT && event_id == IP_EVENT_GOT_IP6) {
	ip_event_got_ip6_t * event = (ip_event_got_ip6_t*)event_data;
	esp_interface_t iface = get_esp_netif_interface(event->esp_netif);
	log_v("IF[%d] Got IPv6: IP Index: %d, Zone: %d, " IPV6STR, iface, event->ip_index, event->ip6_info.ip.zone, IPV62STR(event->ip6_info.ip));
	memcpy(&arduino_event.event_info.got_ip6, event_data, sizeof(ip_event_got_ip6_t));
	if(iface == ESP_IF_WIFI_STA){
	arduino_event.event_id = ARDUINO_EVENT_WIFI_STA_GOT_IP6;
	} else if(iface == ESP_IF_WIFI_AP){
	arduino_event.event_id = ARDUINO_EVENT_WIFI_AP_GOT_IP6;
	} else if(iface == ESP_IF_ETH){
	arduino_event.event_id = ARDUINO_EVENT_ETH_GOT_IP6;
	}

Tests scenarios

Tested on Olimex POE ESP32 board, now connecting Ethernet to a network supporting IPv6 SLAAC, ARDUINO_EVENT_ETH_GOT_IP6 is correctly sent to callbacks. Before this fix, no event was called.

Related links

[mrengineer7777]

Code analysis performed on arduino-esp32 v2.0.5. Disclaimer: I don't fully understand why WiFiGeneric tracks eth_netif_t entries, or how ETH module works.

Discussion:

add_esp_interface_netif() isn't used anywhere else in code. If used, it should probably be exported in WiFiGeneric.h.

WiFiGeneric.cpp keeps track of network interfaces in private array static esp_netif_t* esp_netifs[ESP_IF_MAX] = {NULL, NULL, NULL}. Entries for AP and STA interfaces appear to be directly created in wifiLowLevelInit(), but the ethernet entry is not setup(?).

Ethernet interface is created in ETH begin:

bool ETHClass::begin(uint8_t phy_addr, int power, int mdc, int mdio, eth_phy_type_t type, eth_clock_mode_t clock_mode, bool use_mac_from_efuse)
{
...
    esp_netif_config_t cfg = ESP_NETIF_DEFAULT_ETH();
    esp_netif_t *eth_netif = esp_netif_new(&cfg);
...
}

I agree eth_netif should be registered with WiFiGeneric. I also agree add_esp_interface_netif(ESP_IF_ETH, eth_netif); is the correct way to register it. Not sure on placement of add_esp_interface_netif(), but seems reasonable. Definitely needs to be before esp_eth_start(), and makes sense to not add it until after esp_netif_attach().

Note ETHClass::begin() creates a new eth_netif_t entry every time it is called. If ETHClass::end() [#5949] is added later, end() may need to unregister the ESP_IF_ETH entry.

Would it be better to create the ethernet entry in wifiLowLevelInit()? Side effects unknown.

[TD-er]

Yep, WiFi events also need to be unregistered, or else you will get them multiple times.

N.B. For WiFi events you need to register their callback function(s) each time you enable some interface that wasn't enabled before. e.g. AP only will not register STA events.

So it makes sense to register these events when you call begin() and unregister them when you call end().
However, if my memory serves me well, there wasn't an end() function for ETH.

If there still isn't an end() function, then you can register those events in the lowlevel init function (given it will only called once)

[mrengineer7777]

@TD-er

Yep, WiFi events also need to be unregistered, or else you will get them multiple times.

wifiLowLevelInit() checks for event handle before registering again. Looks safe.

N.B. For WiFi events you need to register their callback function(s) each time you enable some interface that wasn't enabled before. e.g. AP only will not register STA events.

AP and STA registered once in wifiLowLevelInit().

So it makes sense to register these events when you call begin() and unregister them when you call end(). However, if my memory serves me well, there wasn't an end() function for ETH.

Correct. Currently no ETH.end().

[TD-er]

AP and STA registered once in wifiLowLevelInit().

But when you add your own event callback functions, the ones meant for interfaces not being enabled, will not be registered.