GNU/Linux: getting value of option 15 of DHCP without using `getnameinfo`

Question

My GNU/Linux machine is connected to a DHCP. I want to retrieve the value of the option 015 of DHCP (DNS Domain Name), but without using getnameinfo, since it is using DNS in order to retrieve domain name.

How can I do that with C/C++?

Answer 1

My dhclient writes a pile of lease information into /var/lib/dhcp3/dhclient-[uuid]-[iface].lease files. I haven't got a clue what the uuid in those filenames represents, but it does report the different options from the dhcp server.

Answer 2

Fore SUSE: DHCP options are written in /var/lib/dhcpcd/dhcpcd-eth[x].info