Linux Ethernet Bridging - Aug 2022 - [Bridge] [PATCH v5 net-next 1/6] net: bridge: add locked entry fdb flag to extend locked port feature

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.
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...?

On Mon, Aug 29, 2022 at 04:02:46PM +0200, netdev at 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...?