Let's use the new flag wherever we read key material/passphrases/hashes
off disk, so that people can plug in their own IPC service as backend if
they like, easily.
(My main goal was actually to support this for crypttab key files — i.e.
that you can specify AF_UNIX sockets as third column in crypttab — but
that's harder to implement, since the keys are read via libcryptsetup's
API, not ours.)
In NetworkdBridgeTests.test_bridge_configure_without_carrier of
systemd-networkd-tests.py
```
bridge99: MAC address: 2e:3a:ec:4d:d3:62
Assertion 'sd_ipv4ll_is_running(ll) == 0' failed at src/libsystemd-network/sd-ipv4ll.c:110, function int sd_ipv4ll_set_mac(sd_ipv4ll *, const struct ether_addr *)(). Ignoring.
bridge99: Could not update MAC address in IPv4LL client: Device or resource busy
```
sd_netlink_message_set_flags is called without NLM_F_ACK which results in
a timeout while networkd is waiting for an ACK that the kernel will never send.
If DHCP4 client lost a lease, and then soon acquire new lease, then
the removal of the old address may not be completed. If that happens,
and the new and old addresses are the same, then the new address will be
considered as a foreign address. Such a situation can occur when the
DHCP4 server is restarted.
This makes networkd wait for the removal of the old address when a new
lease is acquired.
This also makes the link in configuring state when renewing address.
When DHCP6 and RA are enabled, and RA does not provide any addresses,
then link may become configured state even if no address is assigned,
due to the time-lag between RA completion and DHCP reply.
This makes if DHCP is explicitly enabled, then link must have at least
one valid address to be in the configured state.
Add support for creating a MACVLAN interface in "source" mode by
specifying Mode=source in the [MACVLAN] section of a .netdev file.
A list of allowed MAC addresses for the corresponding MACVLAN can also
be specified with the SourceMACAddress= option of the [MACVLAN] section.
An example .netdev file:
[NetDev]
Name=macvlan0
Kind=macvlan
MACAddress=02:DE:AD:BE:EF:00
[MACVLAN]
Mode=source
SourceMACAddress=02:AB:AB:AB:AB:01 02:CD:CD:CD:CD:01
SourceMACAddress=02:EF:EF:EF:EF:01
The same keys can also be specified in [MACVTAP] for MACVTAP kinds of
interfaces, with the same semantics.