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Mon, 22 Jun 2026 01:32:26 -0700 (PDT) Date: Mon, 22 Jun 2026 10:32:23 +0200 From: Beniamino Galvani To: Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= Cc: Ralf Lici , netdev@vger.kernel.org, Daniel =?iso-8859-1?Q?Gr=F6ber?= , Antonio Quartulli , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org Subject: Re: [RFC net-next 08/15] ipxlat: add translation engine and dispatch core Message-ID: References: <20260319151230.655687-1-ralf@mandelbit.com> <20260319151230.655687-9-ralf@mandelbit.com> <87a4tab1vs.fsf@toke.dk> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87a4tab1vs.fsf@toke.dk> On Thu, Jun 04, 2026 at 08:23:51PM +0200, Toke Høiland-Jørgensen wrote: > Ralf Lici writes: > > > This commit introduces the core start_xmit processing flow: validate, > > select action, translate, and forward. It centralizes action resolution > > in the dispatch layer and keeps per-direction translation logic separate > > from device glue. The result is a single data-path entry point with > > explicit control over drop/forward/emit behavior. > > > > Signed-off-by: Ralf Lici > > This is very cool! Going quickly through the series, this seems like > thorough work that will be cool to have available in the kernel, so > thanks for doing this! I'll be quite happy to retire my barebones > BPF-based implementation once this lands :) Hi, speaking as a maintainer of NetworkManager, I would also like to see this feature in the kernel! In NetworkManager currently we are using a BPF program [1] to implement the CLAT, but that approach comes with limitations: for example, we can't fragment v4->v6 packets if needed, and it's not possible to recompute checksums in certain cases (e.g. for v4->v6 UDP packets with zero checksum, and for fragmented ICMP). systemd-networkd is also adding CLAT support via BPF [2], with a fallback to userspace for the cases that can't be handled in kernel. It would be very useful to have a native in-kernel CLAT that solves the limitations of BPF-based solutions, and can be used by different tools without having to re-implement everything from scratch. Beniamino [1] https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/blob/1.57.2-dev/src/core/bpf/clat.bpf.c [2] https://github.com/systemd/systemd/pull/41412