Re: [PATCH v5 net-next 1/6] net: bridge: add locked entry fdb flag to extend locked port feature

Ido Schimmel
2022-08-29T16:19:24Z

On Mon, Aug 29, 2022 at 04:02:46PM +0200, netdev@kapio-technology.com wrote:
> On 2022-08-27 13:30, Nikolay Aleksandrov wrote:
> > On 26/08/2022 14:45, Hans Schultz wrote:
> >
> > Hi,
> > Please add the blackhole flag in a separate patch.
> > A few more comments and questions below..
> >
>
> Hi,
> if userspace is to set this flag I think I need to change stuff in
> rtnetlink.c, as I will need to extent struct ndmsg with a new u32 entry as
> the old u8 flags is full.

You cannot extend 'struct ndmsg'. That's why 'NDA_FLAGS_EXT' was
introduced. See:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2c611ad97a82b51221bb0920cc6cac0b1d4c0e52

'NTF_EXT_BLACKHOLE' belongs in 'NDA_FLAGS_EXT' like you have it now, but
the kernel should not reject it in br_fdb_add().

> Maybe this is straight forward, but I am not so sure as I don't know that
> code too well. Maybe someone can give me a hint...?