This is for 6d36464065. It turns out that this is causing more problems than
expected. Let's retroactively introduce naming scheme v241 to conditionalize
this change.
Follow-up for #12792 and 6d36464065. See also
https://bugzilla.suse.com/show_bug.cgi?id=1136600.
$ SYSTEMD_LOG_LEVEL=debug NET_NAMING_SCHEME=v240 build/udevadm test-builtin net_setup_link /sys/class/net/br11
$ SYSTEMD_LOG_LEVEL=debug NET_NAMING_SCHEME=v241 build/udevadm test-builtin net_setup_link /sys/class/net/br11
...
@@ -20,11 +20,13 @@
link_config: could not set ethtool features for br11
Could not set offload features of br11: Operation not permitted
br11: Device has name_assign_type=3
-Using interface naming scheme 'v240'.
+Using interface naming scheme 'v241'.
br11: Policy *keep*: keeping existing userspace name
br11: Device has addr_assign_type=1
-br11: No stable identifying information found
-br11: Could not generate persistent MAC: No data available
+br11: Using "br11" as stable identifying information
+br11: Using generated persistent MAC address
+Could not set Alias=, MACAddress= or MTU= on br11: Operation not permitted
+br11: Could not apply link config, ignoring: Operation not permitted
Unload module index
Unloaded link configuration context.
ID_NET_DRIVER=bridge
This suppress the following warning:
```
systemd-udevd[437]: Config file /usr/lib/systemd/network/99-default.link
applies to device based on potentially unpredictable interface name 'wlan0'
```
Follow-up for 84ea567eb4.
Fixes#3374. The problem is that we set MACPolicy=persistent (i.e. we would
like to generate persistent MAC addresses for interfaces which don't have a
fixed MAC address), but various virtual interfaces including bridges, tun/tap,
bonds, etc., do not not have the necessary ID_NET_NAME_* attributes and udev
would not assing the address and warn:
Could not generate persistent MAC address for $name: No such file or directory
Basic requirements which I think a solution for this needs to satisfy:
1. No changes to MAC address generation for those cases which are currently
handled successfully. This means that net_get_unique_predictable_data() must
keep returning the same answer, which in turn means net_get_name() must keep
returning the same answer. We can only add more things we look at with lower
priority so that we start to cover cases which were not covered before.
2. Like 1, but for IPvLL seed and DHCP IAD. This is less important, but "nice
to have".
3. Keep MACPolicy=persistent. If people don't want it, they can always apply
local configuration, but in general stable MACs are a good thing. I have never
seen anyone complain about that.
== Various approaches that have been proposed
=== https://github.com/systemd/systemd/issues/3374#issuecomment-223753264 (tomty89)
if !ID_BUS and INTERFACE, use INTERFACE
I think this almost does the good thing, but I don't see the reason to reject ID_BUS
(i.e. physical hardware). Stable MACs are very useful for physical hardware that has
no physical MAC.
=== https://github.com/systemd/systemd/issues/3374#issuecomment-224733069 (teg)
if (should_rename(device, true))
This means looking at name_assign_type. In particular for
NET_NAME_USER should_rename(..., true) returns true. It only returns false
for NET_NAME_PREDICTABLE. So this would cover stuff like br0, bond0, etc,
but would not cover lo and other devices with predictable names. That doesn't
make much sense.
But did teg mean should_rename() or !should_rename()?
=== https://github.com/systemd/systemd/issues/3374#issuecomment-234628502 (tomty89):
+ if (!should_rename(device, true))
+ return udev_device_get_sysname(device)
This covers only devices with NET_NAME_PREDICTABLE. Since the problem applies as
much to bridges and such, this isn't neough.
=== https://github.com/systemd/systemd/issues/3374#issuecomment-281745967 (grafi-tt)
+ /* if the machine doesn't provide data about the device, use the ifname specified by userspace
+ * (this is the case when the device is virtual, e.g., bridge or bond) */
+ s = udev_device_get_sysattr_value(device, "name_assign_type");
+ if (s && safe_atou(s, &type) >= 0 && type == NET_NAME_USER)
+ return udev_device_get_sysname(device);
This does not cover bond0, vnet0, tun/tap and similar.
grafi-tt also proposes patching the kernel, but *not* setting name_assign_type
seems intentional in those cases, because the device name is a result of
enumeration, not set by the userspace.
=== https://github.com/systemd/systemd/issues/3374#issuecomment-288882355 (tomty89)
(also PR #11372)
- MACAddressPolicy=persistent
This break requirement 3. above. It would solve the immediate problem, but I
think the disruption is too big.
=== This patch
This patch means that we will set a "stable" MAC for pretty much any virtual
device by default, where "stable" means keyed off the machine-id and interface
name.
It seems like a big change, but we already did this for most physical devices.
Doing it also for virtual devices doesn't seem like a big issue. It will make
the setup and monitoring of virtualized networks slightly nicer. I don't think
anyone is depending on having the MAC address changed when those devices are
destoryed and recreated. If they do, they'd have to change MACAddressPolicy=.
== Implementation
net_get_name() is called from dhcp_ident_set_iaid() so I didn't change
net_get_name() like in grafi-tt's patch, but net_get_unique_predictable_data().
net_get_unique_predictable_data() is called from get_mac() in link-config.c
and sd_ipv4ll_set_address_seed(), so both of those code paths are affected
and will now get data in some cases where they errored out previously.
The return code is changed to -ENODATA since that gives a nicer error string.
If "keep" policy is specified, and the interface has a name that is
NET_NAME_USER or NET_NAME_RENAMED, we stop processing rules. "keep" should
probably be specified either first or last depending on the preference.
This partially reimplements 55b6530baa, in the
sense that if the "keep" policy is not specified, and if the interface has
a NamingPolicy, it will be renamed, even if it had a name previously.
So this breaks backwards compatibility in this case, but that's more in line
with what users expect.
Closes#9006.
What policy we dicide to use it rather important, but this bit of information
wasn't logged. Let's always do that.
The code was also written in a confusing way, which probably contributed to the
unintended effects of 55b6530baa and other commits.
We would loop over all policies, and note if "kernel" was specified, and then
possibly unset the result at the end. Let's immediately log the result and cut
to the end if we can figure out the answer.
No functional change intended, except for the new log lines.
Using goto is not very elegant, but we can't use break because of the switch,
and there are multiple conditions to break the loop, so using goto is cleanest.
This reverts commit 55b6530baa.
This commit description says "Always rename an interface to its name specified
in config if no NamePolicy= is specified", but it does much more:
1. It completely changes the meaning of NamePolicy=kernel. Before, it meant that an interface
with type==NAMEPOLICY_KERNEL would not be renamed. After, the kernel name only works as
a fallback, if no policy matches.
2. The "if no NamePolicy= is specified" part is not true at all, the interface will be renamed
according to the specified NamePolicy=.
After 55b6530baa, the should_rename() function is named very misleadingly: it is only used
to mean "respect kernel predictable name if no naming policy matches".
Let's revert, and start with a clean slate. This fixes#11436.
The "features" fields is parsed as a tristate value. The values
are thus not of type NetDevFeature enum but int. The NetDevFeature
enum is instead the index for the features array.
Adjust the type. In practice, this had no impact because NetDevFeature
enum commonly has size of int.
Also, don't use memset() 0xFF to initilize the int with -1. While
it works correctly in practice, it feels ugly.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Yu Watanabe