Subject: Re: [patch net-next rfc 7/7] net: rtnetlink: add possibility to use alternative names as message handle

From: Jiri Pirko <[email-masked]>
Date: Sat, 20 Jul 2019 09:22:50 +0200

Sat, Jul 20, 2019 at 05:59:27AM CEST, [email-masked] wrote:
>On Fri, 19 Jul 2019 13:00:29 +0200, Jiri Pirko wrote:
>> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
>> index 1fa30d514e3f..68ad12a7fc4d 100644
>> --- a/net/core/rtnetlink.c
>> +++ b/net/core/rtnetlink.c
>> @@ -1793,6 +1793,8 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
>>  	[IFLA_MAX_MTU]		= { .type = NLA_U32 },
>>  	[IFLA_ALT_IFNAME_MOD]	= { .type = NLA_STRING,
>>  				    .len = ALTIFNAMSIZ - 1 },
>> +	[IFLA_ALT_IFNAME]	= { .type = NLA_STRING,
>> +				    .len = ALTIFNAMSIZ - 1 },
>
>What's the disadvantage of just letting IFLA_IFNAME to get longer 
>on input? Is it just that the handling would be asymmetrical?

Hmm, that might work. But the problem is that sometimes the IFLA_IFNAME
is used as a handle, but sometimes it is used to carry the ifname
(newlink, changename). That might be a bit confusing and the code would
be harder to follow. I don't know...

>
>>  };
>>  
>>  static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
>