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.
The SSID fills the role of the optional Network_ID input parameter
suggested by RFC7217. Including the SSID allows networkd to generate a
different pseudorandom address for different wireless networks, which
should help to obscure the host's identity when roaming between multiple
networks.
https://github.com/systemd/systemd/pull/29582 adds the "v254" name. This also
changes what the default is and what "latest" refers to. Without the name, the
code could be enabled via runtime configuration. Nevertheless, it could be
enabled at compilation time. In other words:
meson setup build -Ddefault-net-naming-scheme=v254
would work, but
net.naming-scheme=v254
would fail.
It is possible that people were using the compile-time override, so I think
we should allow "v254" scheme to stay and clearly document that it wasn't the
default.
Unfortunately, unless people manually introduced the compile-time override, we
were never actually testing the new code too. So all the pull request testing
was not useful.
But the directories are changed from /dev/loop/by-ref/ -> /dev/disk/by-loop-ref/
and /dev/loop/by-inode/ -> /dev/disk/by-loop-inode/.
As /dev/loop/ is used by losetup command for other purpose.
See issue #28475.
This effectively reverts commits 9915cc6086,
5022fab15f, and
c0d998248e.
This is clearly a change that can break existing units, and broke my
system in at least two different ways. For this reason this should have
been added to NEWS in #26458, specifically c2da3bf, but wasn't.
As mentioned in the NEWS entry, it seems to see very little use, but adds
complexity in our code. It was added mainly with the goal of making it easier
for people using grub2 to modify their boot configuration, but grub2 is gaining
support for BLS snippets. On the systemd side, we now have credentials. So
let's deprecate this, and if there's no outcry, remove it in a few releases.
