Get DHCP lease ips from /var/lib On Linux based operating systems

[AlonHaviv1]

On various Linux based network managers, the DHCP leases are stored on various files.

For example, in NetworkManager, The DHCP lease ip are stored in /var/lib/NetworkManager/\*.lease.
In dhclient, these are stored in /var/lib/dhcp/dhclient.leases.

Those are sample of a better solution to finding Target Ip, instead of parsing syslog, which in some cases could be a more resource intensive task.

[Horofic]

Hey @AlonHaviv1 thank you for opening this issue! This is indeed the the case. At the moment, we are carefully moving away from the current implementation in network_managers.py that has this behaviour.

I think this would be a good addition in the new Linux network manager implementation found here. Although you might still want to parse some lines in the syslog or messages as a fallback when the paths you named fail to reveal a DHCP lease.

Lastly, is this something you are willing to pick up in the form of a pull-request?

[JSCU-CNI]

We added a temporary solution for lease files in #965. We leave it up to you @Horofic to decide how this would fit in the new Linux network plugin structure. For now this adds support for target.ips.