Fix regex parsing of lease file mixing up lease entries

[Gerrit91]

Description

The regex is erroneous and potentially dangerous. Sometimes the isc-dhcp-server can produce lease entries with a hardware ethernet line. For example:

lease 10.0.0.129 {
  starts 4 2026/01/08 14:43:55;
  ends 5 2026/01/09 14:43:55;
  cltt 4 2026/01/08 14:43:55;
  binding state abandoned;
  next binding state free;
  rewind binding state free;
}
lease 10.0.0.1 {
  starts 4 2026/01/08 14:44:02;
  ends 6 2026/01/10 14:44:02;
  cltt 4 2026/01/08 14:44:02;
  binding state active;
  next binding state free;
  rewind binding state free;
  hardware ethernet 00:00:00:00:00:01;
  uid "\001<\354\357\202\006 ";
}

The regex then parses in a lease with IP 10.0.0.129 and mac address 00:00:00:00:00:01. Potential lease entries between are dropped. The association is broken.

[majst01]

Was done once in the past here #52 but closed with the hope of migrating to kea.

Another option would be IMHO to integrate a dhcp server into metal-bmc, for example with the help of https://github.com/coredhcp/coredhcp. With this approach we would not have to parse anything and deployment could be potentially easier.

[Gerrit91]

I am not sure who should drive the kea migration. I would be better for sure but we have so many topics to work that I am not sure if we can do it.

Integrating the DHCP server into metal-bmc would mean that we cannot put the dhcp server and metal-bmc in different locations anymore, which might be an issue for some setups.

[majst01]

I am not sure who should drive the kea migration. I would be better for sure but we have so many topics to work that I am not sure if we can do it.

Integrating the DHCP server into metal-bmc would mean that we cannot put the dhcp server and metal-bmc in different locations anymore, which might be an issue for some setups.

Agreed with both