It would be useful to see support for RFC 6939 added to dhcrelay for DHCPv6.
Specifically, the insertion of OPTION_CLIENT_LINKLAYER_ADDR (79) , which provides the client MAC to dhcpd as a relay option.
It would be useful to see support for providing external programs information on DHCPv6-PD prefix assignments so that systems used as routers could then take action to add routes for delegated prefixes.
This could be as simple as (1) creating a log event with the needed information (prefix, expiry, and next-hop) that could be streamed to a specific file; or (2) adding support to call an external script with the information past as a list of as arguments; or (3) maintaining a prefix-delegation database that keeps track of active prefixes delegated.
My personal preference would be the second option to call an external script.
These two items are important for enabling IPv6 with DHCPv6 for open source network routers and firewall projects, such as VyOS.
They also compliment functionality already in DHCPd, and would provide a way to leverage these features without the use of proprietary relay agents.
I know that dhcrelay is not seen as a high priority for the project, but I hope I can convey how important this functionality is for both IPv6 adoption as well as open source router and firewall adoption.
Ray Patrick Soucy
Senior Cyber Security Engineer
Networkmaine, University of Maine System US:IT