This fixes a race where dhcp4 started before netconfigd had a chance to change
the hardware address on the uplink0 interface.
fiber7’s port security feature may result in an about hour-long internet outage
without this commit.
All existing DHCPv4 packages I looked at were unappealing for one reason or
another, so we’re now using a little helper to glue github.com/google/gopacket
and github.com/mdlayher/raw together, which suffices for our use-case and gives
us more control.
