Re: [lwip-users] Question about DHCP server and 2nd layer delivery

[Sergio R. Caprile]

There is DHCP server code around, IIRC Axel Lin talked about one on this 
list. The people from Espressif has one for their ESP chips (they use 
lwIP...), though I don't know which API they use, as well as I don't 
either know which one you intend to use.
I guess by "2nd layer delivery" you mean sending layer-2 data, Ethernet 
frames... (or Wi-Fi...) Well, since lwIP understands IP, and the driver 
to get and send Ethernet frames is your business (though you might be 
using a vendor port and didn't notice this), you can actually do it. 
Getting frames back is a bit trickier 'cause you have to know when it is 
for you and when for lwIP, unless of course you use a non-IP layer-3.
There is some code for LLDP around in the list (and/or the repo ?), 
check it out. However, AFAIK DHCP runs on UDP and you can send UDP 
broadcasts from within lwIP (although I've never written a DHCP server 
and I might be missing something important here)