With the announced EOL of the venerable ISC DHCP Server it is time to
migrate this test to Kea, it's successor.
The ISP has also received an upgrade to its interface configuration,
which now happens completely through networkd.
https://www.isc.org/blogs/isc-dhcp-eol/
Adapt to changes introduced in Systemd 250:
> The [DHCPv6PrefixDelegation] section in .network file is renamed to
> [DHCPPrefixDelegation], as now the prefix delegation is also
> supported with DHCPv4 protocol by enabling the Use6RD= setting.
Replaces the `dhcpV6PrefixDelegationConfig` with
`dhcpPrefixDelegationConfig` and throws an error if the old option is
used.
Also adapt the respective IPv6 prefix delegation test.
Since dhcpd has been hardened (DynamicUser → NoNewPrivileges) it can't
use a setcap wrapper. Instead, we add the net_admin capability to it's
ambient set and run `ip route` directly. This is also safer that giving
everyone permisison to change the routing table.
According to RFC4291[1], 2001:db8:: is the anycast address for the
prefix and will be answered by all routers responsible for this prefix.
This means that before the iputils bump, the ping from client to isp was
answered by the router and not by the ISP machine. Switching away from
the anycast address fixes this issue.
Credits for finding this go to @primeos.
[1]: https://tools.ietf.org/html/rfc4291#section-2.6.1Fixes#96188
This is a follow-up to the PR #82026 that contains the promised tests.
In this test I am testing if we can properly propagate prefixes received
via DHCPv6 PD with the networkd options in our module system.
The comments in the test should be sufficient to follow the idea and
what is going on.
