[lwip-users] Getting Raw ARP Packets

[David M. Zar]

I'm somewhat new to using LWIP (version 2.0.3) and am making great 
progress with my application which will include processing raw IP 
packets. One problem is that we also need to accept and pass on ARP 
packets. I don't see an easy way to do this without modifying code in 
etharp.c. Would this be the accepted method?

Some details... I am creating an application where my device will be a 
"bump-on-the-wire." My device will not have an IP address and will 
accept UDP/TCP packets (in raw mode) from the network and pass them on 
to a host connected at the other side. Likewise, I will accept UDP/TCP 
from the host and pass them on to the network side. I can do that. But I 
also need to handle ARP. When an ARP packet shows up from the network 
side, I need to pass it on to the host who will then respond. That 
response will then need to go back to the network.

Optionally, I could simply know the appropriate ARP response to send for 
my host and send it as soon as I see an ARP packet with my host's IP 
address, but that's a minor difference. I still need to accept ARP 
packets and process them, myself, and not expect the LWIP stack to do so.

Thanks for any insights/suggestions you may have.

Dave