Re: [PATCH iproute2-next] ip nexthop: support fdb destination port

[Jack Ma <jack4it@gmail.com>]

On Wed, Jul 22, 2026 at 06:19:04PM +0300, Ido Schimmel wrote:
> FWIW, I don't post iproute2 changes before the kernel changes are
> accepted. I put a link in the kernel cover letter to the repo where I
> have the iproute2 patches.

Thanks, understood.  The kernel cover letter links this iproute2 series,
and I posted it here only to make the userspace half easy to review
alongside -- it shouldn't be applied before the kernel attribute is
accepted.

> You need to perform this change in a separate patch. Example:
> https://lore.kernel.org/netdev/20260320140847.1730633-2-justin.iurman@6wind.com/

Done in v2.  The uapi header sync is now its own patch ("uapi: add
NHA_DST_PORT"), matching that example, with the ip nexthop changes in a
second patch.

> Missing update to the man page

Done in v2.  ip-nexthop.8 now documents dst_port in the synopsis and the
attribute description, with an example.

> Assuming we go with "dst_port", you can drop "fdb". Only the kernel will
> validate that "dst_port" is provided together with "fdb".

Done.  We did go with "dst_port" (NHA_DST_PORT) on the kernel side, so
usage is now a standalone "[ dst_port PORT ]" -- the "fdb" nesting is
gone and the kernel enforces the dst_port + fdb pairing.

> The convention here is "port %u ", not " port %u". I think you added it
> like that because there's a missing space in "fdb" above. Fix it while
> you are at it.

Done in v2.  Printing is now "dst_port %u " with the trailing space, and
I fixed the pre-existing missing space in the "fdb" print above it too.

v2:
  https://lore.kernel.org/netdev/20260723-b4-vxlan-fdb-port-iproute2-v2-0-9012ac01b49e@gmail.com/

Thanks,
Jack