Feature Request: [odhcpd] Add Authentication option (RFC 3118/8415)

[Kevin Vigouroux]

Hi!

I would have liked to add the authentication option in odhcpd. 

My network topology is constrained by my ISP. Indeed, I have to keep my ISP's
router in a subnet to be able to get VoIP (Unfortunately, their implementation
of the SIP protocol is proprietary. They don't want an open source solution).

The DHCPv4/v6 client on my ISP's CPE controls their messages with the ISP's
DHCPv4/v6 server with the "Configuration Token" protocol (RFC 3118). odhcpd uses
the RKAP protocol (RFC 8415) for its FORCERENEW (DHCPv4) and Reconfigure
(DHCPv6) messages.

I'm not sure how to go on. I'm still inexperienced in programming and don't know
many concepts. I started by reading the libubox (blob.c, blobmsg.c) and uci
(file.c, libuci.c, list.c...) sources.

My ISP uses the Configuration Token protocol for Discover, Offer, Request,
Acknowledge messages (DHCPv4). odhcpd uses the RKAP protocol for FORCERENEW
messages (DHCPv4). I would have liked to do something simple, because I'm not
competent. There could be a problem of priority in how to select the right
protocol. I would have thought of using the Configuration Token protocol for
DORA messages alongside the RKAP protocol for FORCENEW messages. I don't know
if this is a good idea?

To start with, I'd like to implement a solution for DHCPv4.

Note: dnsmasq is not an alternative because I also want to use unbound.
-- 
Best regards,
Kevin Vigouroux