chrony is appears to keep the RTC open continuously these days which is
a bad idea, and /dev/rtc is a single-user device, which is a bad idea
too. Together both bad ideas mean that nobody else can access the RTC
anymore. That's something to fix, but in the meantime we should handle
this more gracefully.
We set it to 10 secs (as we are only communicating with the kernel,
it seems we should be able to bail out sooner than sd-bus, which
uses 25).
When passing timout 0, the default is used, use this in link-config.
Suggested by David Wilkins <dwilkins@maths.tcd.ie> in
https://bugzilla.redhat.com/show_bug.cgi?id=967521:
> [Specific boot ID is a] bit of a palaver to obtain. I consulted the
> verbose dump of the journal to discover the _BOOT_ID for the
> timestamp, and then generated the journal dump for that boot using
> journalctl _BOOT_ID=foo -o short-monotonic.
This introduces a new key MACAddressPolicy.
The possible policies are 'persistent' and 'random'.
'persistent' will do nothing if the current address is the hardware address,
but if the hardware does not have an address (or another address is set for
whatever reason), we will generate an address which will be random, but
persistent between boots (based on machineid and persistent netif name).
'random' will do nothing if the kernel already set a random address, otherwise
it will generate a random one and use that instead.
This patch sets MACAddressPolicy=persistent in the default .link file.
This introduces a new key NamePolicy, which takes an ordered list of naming
policies. The first successful one is applide. If all fail the value of Name
(if any) is used.
The possible policies are 'onboard', 'slot', 'path' and 'mac'.
This patch introduces a default link file, which replaces the equivalent udev
rule.
This is intentionally as similar to sd-bus as possible. While it
would be simple to export it, the intentions is to keep this
internal (at least for the forseeable future).
Currently only synchronous communication is implemented
This tool applies hardware specific settings to network devices before they
are announced via libudev.
Settings that will probably eventually be supported are MTU, Speed,
DuplexMode, WakeOnLan, MACAddress, MACAddressPolicy (e.g., 'hardware',
'synthetic' or 'random'), Name and NamePolicy (replacing our current
interface naming logic). This patch only introduces support for
Description, as a proof of concept.
Some of these settings may later be overriden by a network management
daemon/script. However, these tools should always listen and wait on libudev
before touching a device (listening on netlink is not enough). This is no
different from how things used to be, as we always supported changing the
network interface name from udev rules, which does not work if someone
has already started using it.
The tool is configured by .link files in /etc/net/links/ (with the usual
overriding logic in /run and /lib). The first (in lexicographical order)
matching .link file is applied to a given device, and all others are ignored.
The .link files contain a [Match] section with (currently) the keys
MACAddress, Driver, Type (see DEVTYPE in udevadm info) and Path (this
matches on the stable device path as exposed as ID_PATH, and not the
unstable DEVPATH). A .link file matches a given device if all of the
specified keys do. Currently the keys are treated as plain strings,
but some limited globbing may later be added to the keys where it
makes sense.
Example:
/etc/net/links/50-wireless.link
[Match]
MACAddress=98:f2:e4:42:c6:92
Path=pci-0000:02:00.0-bcma-0
Type=wlan
[Link]
Description=The wireless link
This matches the bcma support in the network device naming.
Eventually wa want to make sure ID_PATH is equivalent to ID_NET_NAME_PATH,
so we never need to match on the latter.
Lennart Poettering
Tom Gundersen
Zbigniew Jędrzejewski-Szmek
David Strauss
Martin Pitt
Daniel Buch
Dave Reisner
Thomas Hindoe Paaboel Andersen
Kay Sievers