[lwip-users] Sending frames without IP

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Hi,

I am using the "LWIP_IP_ACCEPT_UDP_PORT" feature to enable communication even when the device has not yet been configured with an IP-address.

This works as it should, I can receive broadcast UDP requests directed at a specific port.
I am however unable to respond to the request. (I use broadcast response of course)

udp_sendto() calls ip_route(), which takes a look at netif_is_up(netif_default) and figures that since the default netif is not up, the UDP frame should be dropped.

Is there a way around this? Or do I have to modify ip_route to allow broadcast traffic even when the netif is down?


Shouldn't netif_is_up() actually indicate if there is a physical link on the interface, and ip_addr=0x00000000 indicate that the interface is unconfigured? It looks like that was the intention in some places of the code.

Regards,
Timmy Brolin