Message-Id: <20170821171523.951260-1-equinox@diac24.net>
Date:   Mon, 21 Aug 2017 19:15:17 +0200
From:   David Lamparter <equinox@...c24.net>
To:     netdev@...r.kernel.org, bridge@...ts.linux-foundation.org
Cc:     amine.kherbouche@...nd.com, roopa@...ulusnetworks.com,
        stephen@...workplumber.org
Subject: [RFC net-next v2] bridge lwtunnel, VPLS & NVGRE

Hi all,


this is an update on the earlier "[RFC net-next] VPLS support".  Note
I've changed the subject lines on some of the patches to better reflect
what they really do (tbh the earlier subject lines were crap.)

As previously, iproute2 / FRR patches are at:
- https://github.com/eqvinox/vpls-iproute2
- https://github.com/opensourcerouting/frr/commits/vpls
while this patchset is also available at:
- https://github.com/eqvinox/vpls-linux-kernel
(but please be aware that I'm amending and rebasing commits)

The NVGRE implementation in the 3rd patch in this series is actually an
accident - I was just wiring up gretap as a reference;  only after I was
done I noticed that that sums up to NVGRE, more or less.  IMHO, it does
serve well to demonstrate the bridge changes are not VPLS-specific.

To refer some notes from the first announce mail:
> I've tested some basic setups, the chain from LDP down into the kernel
> works at least in these.  FRR has some testcases around from OpenBSD
> VPLS support, I haven't wired that up to run against Linux / this
> patchset yet.

Same as before (API didn't change).

> The patchset needs a lot of polishing (yes I left my TODO notes in the
> commit messages), for now my primary concern is overall design
> feedback.  Roopa has already provided a lot of input (Thanks!);  the
> major topic I'm expecting to get discussion on is the bridge FDB
> changes.

Got some useful input;  but still need feedback on the bridge FDB
changes (first 2 patches).  I don't believe it to have a significant
impact on existing bridge operation, and I believe a multipoint tunnel
driver without its own FDB (e.g. NVGRE in this set) should perform
better than one with its own FDB (e.g. existing VXLAN).

> P.S.: For a little context on the bridge FDB changes - I'm hoping to
> find some time to extend this to the MDB to allow aggregating dst
> metadata and handing down a list of dst metas on TX.  This isn't
> specifically for VPLS but rather to give sufficient information to the
> 802.11 stack to allow it to optimize selecting rates (or unicasting)
> for multicast traffic by having the multicast subscriber list known.
> This is done by major commercial wifi solutions (e.g. google "dynamic
> multicast optimization".)

You can find hacks at this on:
https://github.com/eqvinox/vpls-linux-kernel/tree/mdb-hack
Please note that the patches in that branch are not at an acceptable
quality level, but you can see the semantic relation to 802.11.

I would, however, like to point out that this branch has pseudo-working
IGMP/MLD snooping for VPLS, and it'd be 20-ish lines to add it to NVGRE
(I'll do that as soon as I get to it, it'll pop up on that branch too.)

This is relevant to the discussion because it's a feature which is
non-obvious (to me) on how to do with the VXLAN model of having an
entirely separate FDB.  Meanwhile, with this architecture, the proof of
concept / hack is coming in at a measly cost of:
8 files changed, 176 insertions(+), 15 deletions(-)


Cheers,

-David


--- diffstat:
include/linux/netdevice.h      |  18 ++++++
include/net/dst_metadata.h     |  51 ++++++++++++++---
include/net/ip_tunnels.h       |   5 ++
include/uapi/linux/lwtunnel.h  |   8 +++
include/uapi/linux/neighbour.h |   2 +
include/uapi/linux/rtnetlink.h |   5 ++
net/bridge/br.c                |   2 +-
net/bridge/br_device.c         |   4 ++
net/bridge/br_fdb.c            | 119 ++++++++++++++++++++++++++++++++--------
net/bridge/br_input.c          |   6 +-
net/bridge/br_private.h        |   6 +-
net/core/lwtunnel.c            |   1 +
net/ipv4/ip_gre.c              |  40 ++++++++++++--
net/ipv4/ip_tunnel.c           |   1 +
net/ipv4/ip_tunnel_core.c      |  87 +++++++++++++++++++++++------
net/mpls/Kconfig               |  11 ++++
net/mpls/Makefile              |   1 +
net/mpls/af_mpls.c             | 113 ++++++++++++++++++++++++++++++++------
net/mpls/internal.h            |  44 +++++++++++++--
net/mpls/vpls.c                | 550 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20 files changed, 990 insertions(+), 84 deletions(-)

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