Re: [PATCH net] net: enable interface alias removal via rtnl

Le 09/10/2017 à 16:02, David Ahern a écrit :

On 10/9/17 2:23 AM, Nicolas Dichtel wrote:

quoted

Le 06/10/2017 à 22:10, Oliver Hartkopp a écrit :

quoted

On 10/06/2017 08:18 PM, David Ahern wrote:

quoted

On 10/5/17 4:19 AM, Nicolas Dichtel wrote:

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IFLA_IFALIAS is defined as NLA_STRING. It means that the minimal length of
the attribute is 1 ("\0"). However, to remove an alias, the attribute
length must be 0 (see dev_set_alias()).

why not add a check in dev_set_alias that if len is 1 and the 1
character is '\0' it means remove the alias?

Because it requires an iproute2 patch. iproute2 doesn't send the '\0'. With the
command 'ip link set dummy0 alias ""', the attribute length is 0.

iproute2 needs the feature for 0-len strings or perhaps a 'noalias' option.

iproute2 needs nothing ...

You can reset the alias using the sysfs file. Given that there is a
workaround for existing kernels and userspace, upstream can get fixed
without changing the UAPI.

I don't get the point with the UAPI. What will be broken?
I don't see why allowing an attribute with no data is a problem.