[kea-dev] Transitioning Openwrt to Kea

[Philip Prindeville]

Hi,

I am the maintainer for isc-dhcp on Openwrt, and I’m trying to add backend support to move users over to Kea while not breaking their configurations.

I had some questions about what the equivalent Kea configuration commands were.  I had started using the migration tool but there are some cases it doesn’t handle.

Looking at the documentation, for instance, it states that “renew-timer” can be applied globally or per subnet, but I can’t figure out where in the subnet4 declaration it would go.

ISC DHCP had the “always-broadcast” per-subnet or per-host directive, but I can’t figure out what the Kea equivalent is.

Similarly for “authoritative” (and “deny unknown-clients” vs. “ignore unknown-clients”) and “boot-unknown-clients”.

Also, if a host (say my MacBook Pro) can be docked to a docking station with Ethernet *and* roam around via WiFi, but I want it to have the same IP address in both cases, how to do that?  I’ve tried:

        "reservations": [
          {
            "hostname": "Philips-Laptop",
            "hw-address": "c8:89:f3:b3:c4:3c",
            "ip-address": "172.21.12.2",
            "option-data": [
              {
                "name": "host-name",
                "data": "Philips-Laptop"
              }
            ]
          },
          {
            "hostname": "Philips-Laptop",
            "hw-address": "00:e0:4c:08:25:2f",
            "ip-address": "172.21.12.2",
            "option-data": [
              {
                "name": "host-name",
                "data": "Philips-Laptop"
              }
            ]
          },
…

but this just makes it complain:

2024-07-29 22:11:52.549 ERROR [kea-dhcp4.dhcp4/25373.139806395011408] DHCP4_PARSER_FAIL failed to create or run parser for configuration element subnet4: failed to add new host using the HW address '00:e0:4c:08:25:2f and DUID '(null)' to the IPv4 subnet id ‘5' for the address 172.21.12.2: There's already a reservation for this address
Error encountered: failed to add new host using the HW address '00:e0:4c:08:25:2f and DUID '(null)' to the IPv4 subnet id ‘5' for the address 172.21.12.2: There's already a reservation for this address

Can I pass in an array for “hw-address”?

I’ve been working on this off and on for a few months now, and if I can resolve these last few issues then I think the migration tool will be good to go.

If anyone is curious I can post what I have so far, though it hasn’t been completely integrated into the new Kea framework (which requires manual configuration until I can get this frontend working).

Thanks,

-Philip