[systemd-devel] systemd-networkd: setting the MAC address for a .netdev unit?

[Tom Gundersen]

On Mon, May 12, 2014 at 5:27 PM, poma <pomidorabelisima at gmail.com> wrote:
> On 12.05.2014 12:22, Tom Gundersen wrote:
>> On Mon, May 12, 2014 at 10:43 AM, Matthias Schiffer
>> <mschiffer at universe-factory.net> wrote:
>>>>>> This should really be added as AFAICT there is currently no way to match
>>>>>> on virtual devices like briges, TAP devices, batman-adv devices, etc...
>>>>>> which have neither a persistent MAC address nor an ID_PATH to match on.
>>>>>
>>>>> So I think what we should do here is to allow MAC address (and other
>>>>> things) to be set when creating the netdevs. I made an attempt at this
>>>>> by generating a "predictable" one based on the interface name and the
>>>>> machine-id. Would that do it for you, or are you after a _specific_
>>>>> mac address, rather than just one that is always the same? I had to
>>>>> revert the code doing this for now as there was a kernel bug, however
>>>>> we'll hopefully get that sorted soon and then get back to this.
>>>>>
>>>>> Cheers,
>>>>>
>>>>> Tom
>>>>>
>>>>
>>>> For my usecase, a predictable, but otherwise random MAC address would
>>>> do. But I also see that setting an arbitrary MAC address (or any other
>>>> link parameter) for a specific virtual device is useful as well
>>>> (especially as it is possible to do so with real devices). As virtual
>>>> devices are almost always created with specific names, a Name= match for
>>>> .link units would make the most sense in my opinion.
>>>>
>>>> As a workaround, I've added the following udev rule to
>>>> 80-net-setup-link.rules for now to allow matching for virtual devices
>>>> with Path= matches:
>>>>
>>>> ENV{DEVPATH}=="/devices/virtual/net/*", ENV{ID_PATH}=="",
>>>> ENV{ID_PATH}="virtual-$kernel"
>>>>
>>>> Thanks,
>>>> Matthias
>>>>
>>>
>>> Ping. There is still no way to match for virtual devices in .link units
>>> without my workaround. Is it planned to add something similar? Would a
>>> facility allowing to configure the MAC address of a virtual device be in
>>> the scope of the TODO point "add reduced [Link] support to .network files"?
>>
>> Yes. What we will do is that by default we will generate a MAC address
>> that will be stable between reboots and use that, but we will also
>> allow the MAC address to be set manually in the [NetDev] section (in
>> the same way as in the .link files).
>>
>> The kernel interface for doing this is currently broken, but a patch
>> has been submitted to fix it, and once that hits the stable kernels I
>> guess we can start using it (otherwise we are just going to get heaps
>> of weird bug reports).
>>
>> Cheers,
>>
>> Tom
>
> Ping.
> Care to paste link to a patch?

Sure: <http://www.spinics.net/lists/netdev/msg280477.html>

Cheers,

Tom