With this systemd buffers netlink messages in early boot from the kernel
itself; and passes them on to networkd for processing once it's started.
Makes sure no routing messages are missed.
Also makes an alias so that dbus can activate this unit. Upstream has
this too.
This follows upstreams change in documentation. While the `[DHCP]`
section might still work it is undocumented and we should probably not
be using it anymore. Users can just upgrade to the new option without
much hassle.
I had to create a bit of custom module deprecation code since the usual
approach doesn't support wildcards in the path.
You can now specify option for the `[DHCPv6]` section with
`systemd.network.<name>.dhcpV6Config.…`. Previously you could only use
the combined legacy DHCP configuration.
Systemd upstream has deprecated CriticalConnection with v244 in favor of
KeepConnection as that seems to be more flexible:
The CriticalConnection= setting in .network files is now deprecated,
and replaced by a new KeepConfiguration= setting which allows more
detailed configuration of the IP configuration to keep in place.
1d61efb7f1 accidentially changed the
restartTriggers of systemd-networkd.service` to point to the attribute
name (in this case, a location relative to `/etc`), instead of the
location of the network-related unit files in the nix store.
This caused systemd-networkd to not get restarted on activation of new
networking config, if the file name hasn't changed.
Fix this, by pointing this back to the location in the nix store.
This mirrors the behaviour of systemd - It's udev that parses `.link`
files, not `systemd-networkd`.
This was originally applied in 36ef112a47,
but was reverted due to 1115959a8d causing
evaluation errors on hydra.
...even when networkd is disabled
This reverts commit ce78f3ac70, reversing
changes made to dc34da0755.
I'm sorry; Hydra has been unable to evaluate, always returning
> error: unexpected EOF reading a line
and I've been unable to reproduce the problem locally. Bisecting
pointed to this merge, but I still can't see what exactly was wrong.
The options at `systemd.network` (`links`, `netdevs` and `networks`) are
directly mapped to the three different unit types of `systemd-networkd(8)`.
However there's also the option `systemd.network.units` which is
basically used as a container for generated unit-configs that are linked
to `/etc/systemd/networkd`[1].
This should not be exposed to the user as it's unclear whether or not it
should be used directly which can be pretty confusing which is why I decided to
declare this option as internal (including all sub-options as `internal`
doesn't seem to be propagated to submodules).
[1] 9db75ed88f/nixos/modules/system/boot/networkd.nix (L933-L937)
This has been there since v209 [1]
```
The interface name to use. This option has lower precedence than NamePolicy=, so for this setting to take effect, NamePolicy= must either be unset, empty, disabled, or all policies configured there must fail. Also see the example below with "Name=dmz0".
Note that specifying a name that the kernel might use for another interface (for example "eth0") is dangerous because the name assignment done by udev will race with the assignment done by the kernel, and only one interface may use the name. Depending on the order of operations, either udev or the kernel will win, making the naming unpredictable. It is best to use some different prefix, for example "internal0"/"external0" or "lan0"/"lan1"/"lan3".
```
[1] 43b3a5ef61
Both options were introduced in systemd v243[1]. Those options can be
used to ensure that LinkLocalAddressing is only configured for a given
interface if DHCPv4 fails. To quote `systemd.network(5)`:
```
If "fallback" or "ipv4-fallback" is specified, then an IPv4
link-local address is configured only when DHCPv4 fails. If "fallback", an IPv6 link-local
address is always configured, and if "ipv4-fallback", the address is not configured. Note
that, the fallback mechanism works only when DHCPv4 client is enabled, that is, it requires
"DHCP=yes" or "DHCP=ipv4".
```
[1] 8bc17bb3f7
