AllowList= and DenyList= filter only DHCPOFFER messages. So, if
RapidCommit= is enabled, then networkd unconditionally accepts a rapid
ACK message even if its sender is filtered out by the lists.
As AllowList=/DenyList= implemented earlier than RapidCommit=, so
enabling RapidCommit= unconditionally by default may break existing
setups that use AllowList=/DenyList=.
Let's disable RapidCommit= by default when AllowList=/DenyList= is
enabled. Still the setting can be enabled by setting explicitly even
AllowList=/DenyList= is also specified.
When an interface is being reconfigured with different bridge vlan
settings, this makes old vlan IDs on the interface removed.
This also makes the PVID= setting support negative boolean value, e.g. "no",
in which case, the currently assigned PVID (typically, assigned by the
kernel when an interface is joined to a bridge) is dropped.
This feature is requested by #15291.
Note, if a .network file has no settings about bridge vlan, networkd
keeps the currently assigned vlan IDs. That's intended, to make not
break existing setups.
When a .network file has only PVID=no line in [BridgeVLAN] section, then
all assigned vlan IDs are removed.
Fixes#29975.
Closes#15291.
This implements the DHCPv4 equivalent of the DHCPv6 Rapid Commit option,
enabling a lease to be selected in an accelerated 2-message exchange
instead of the typical 4-message exchange.
As I noticed a lot of missing information when trying to implement checking
for missing info. I reimplemented the version information script to be more
robust, and here is the result.
Follow up to ec07c3c80b
