ESP32 Forum

Can the ESP32 send/receive wireless packets for an external lwIP stack (not running on this ESP-WROOM-32 module itself)? We are interested in using the USB serial bridge as a bi-directional network interface to the ESP-32 WiFi radio.

I have experimented with esp_wifi_internal_tx() function and it does return success error codes in my tests, but I haven't yet been able to sniff any actual data...

It is a legitimate commercial application, with some volume potential, and I don't see ANY reason why I shouldn't be able to send aribitrary 802.11 data frames without the overhead of the lwIP stack on the ESP32.

Hoping to hear from Espressif engineer ideally...

Thanks to anyone who has useful information on this issue.

Regards,

Paul Chapman
CTO, ASI Controls

Yes, that should be possible: esp-idf/components/lwip/port/netif/wlanif.c describes the interface used by the internal LWIP; you could disable lwip entirely and use the code there as an interface into the wireless subsystem.

Also, take note that this function does not let you send arbitrary 802.11 frames, but rather Ethernet frames. You need to make sure that connection to an AP or STA is established before you try to send anything using this API.

That said, this is still considered to be an internal API. If you wish that to be changed, please raise your request via Espressif sales channels.