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

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

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

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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.
A kernel patch is probably enough for this problem. Updating iproute2 on old
distributions is not always easy.

Yes. That looks indeed better than changing NLA_STRING to NLA_BINARY which does
not really hit the point.

Nicolas, can you send an updated patch picking up David's suggestion?

Tnx & best regards,
Oliver

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Let's define the type to NLA_BINARY, so that the alias can be removed.

that changes the uapi

I don't understand what will be broken.