Re: [PATCH 3/3 net-next v4] selftests: net: add test for IPv4 devconf netlink notifications

[Fernando Fernandez Mancera <fmancera@suse.de>]

On 5/14/26 4:35 AM, Jakub Kicinski wrote:
> On Sun, 10 May 2026 10:15:28 +0200 Fernando Fernandez Mancera wrote:
>> Introduce a new test, `ipv4_devconf_notify`, to verify that the kernel
>> sends the appropriate netlink notifications when IPv4 devconf parameters
>> are modified.
>>
>> Since YNL currently has a bug where it declares an array of u32 values
>> instead of the nested attributes expected by the kernel for devconf set
>> operations, a temporary hack (`patched_add_attr`) is included to
>> pack the netlink attributes correctly.
> 
> Right, YNL doesn't really support the level or weirdness that netconf
> requires. Why use YNL? Can't we test this with iproute2?
> 

No, AFAIU, iproute2 does not expose devconf settings. The main user of 
IFLA_INET_CONF are netlink libraries and other userspace tools that 
heavily rely on netlink operations like NetworkManager, nmstate, nispor, 
rust-netlink..

FWIW, I plan to fix the YNL side of things so we have this fixed 
properly. But I would prefer if this isn't blocked. Another patchset 
introducing IFLA_INET6_CONF support is also coming.. being able to avoid 
sysctl usage is quite useful for these userspace tools.

> nit: sashiko found a typo in "notificiation"

Should I repost for this?

Thanks for the feedback Jakub, I know everyone is quite busy recently. 
So I really appreciate you took the time to look at it.

Thanks,
Fernando.