how do I get link layer addresses from user-space?

[Fernando Anton <fernando.anton@xxxxxxxx>]

Hi all,

I want to ask you a simple question that I don't get answered by myself: 
how can I get a network address resolver to a link-layer address by the 
kernel ?

In other words...

I have an user-space application which receives IPv4 and IPv6 packets to be 
routed, and I must tell what will be the next hop.
Once I have the next hop (its IPv4 or IPv6 address) I will send it over a 
raw link-layer socket to the destination.. but I need to know its 
link-layer address to do it and.. I do not know how to get it.
I've seen iproute2 sources and walked a little through ipneigh.c sources, 
but I have only found ways to set an ARP entry inside the kernel and to get 
the current ARP cache, but..

how do I trigger an ARP resolution in the kernel from userspace ?

Thanks in advance



Un saludo:
Fernando Anton Alonso aka Mitra / Spanish Lords