From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Tobias Waldekranz <tobias@waldekranz.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
netfilter-devel@vger.kernel.org, davem@davemloft.net,
netdev@vger.kernel.org, razor@blackwall.org, jeremy@azazel.net
Subject: Re: [PATCH net-next,v3 0/9] netfilter: flowtable bridge and vlan enhancements
Date: Mon, 16 Nov 2020 23:31:14 +0100 [thread overview]
Message-ID: <20201116223114.GA6905@salvia> (raw)
In-Reply-To: <87sg9cjaxo.fsf@waldekranz.com>
On Sat, Nov 14, 2020 at 03:00:03PM +0100, Tobias Waldekranz wrote:
> On Sat, Nov 14, 2020 at 12:59, Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > If any of the flowtable device goes down / removed, the entries are
> > removed from the flowtable. This means packets of existing flows are
> > pushed up back to classic bridge / forwarding path to re-evaluate the
> > fast path.
> >
> > For each new flow, the fast path that is selected freshly, so they use
> > the up-to-date FDB to select a new bridge port.
> >
> > Existing flows still follow the old path. The same happens with FIB
> > currently.
> >
> > It should be possible to explore purging entries in the flowtable that
> > are stale due to changes in the topology (either in FDB or FIB).
> >
> > What scenario do you have specifically in mind? Something like VM
> > migrates from one bridge port to another?
>
> This should work in the case when the bridge ports are normal NICs or
> switchdev ports, right?
Yes.
> In that case, relying on link state is brittle as you can easily have a
> switch or a media converter between the bridge and the end-station:
>
> br0 br0
> / \ / \
> eth0 eth1 eth0 eth1
> / \ => / \
> [sw0] [sw1] [sw0] [sw1]
> / \ / \
> A A
>
> In a scenario like this, A has clearly moved. But neither eth0 nor eth1
> has seen any changes in link state.
>
> This particular example is a bit contrived. But this is essentially what
> happens in redundant topologies when reconfigurations occur (e.g. STP).
>
> These protocols will typically signal reconfigurations to all bridges
> though, so as long as the affected flows are flushed at the same time as
> the FDB it should work.
Yes, watching the FDB should allow to clean up stale flows immediately.
prev parent reply other threads:[~2020-11-16 22:31 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-11 19:37 [PATCH net-next,v3 0/9] netfilter: flowtable bridge and vlan enhancements Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 1/9] netfilter: flowtable: add hash offset field to tuple Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 2/9] netfilter: flowtable: add xmit path types Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 3/9] net: resolve forwarding path from virtual netdevice and HW destination address Pablo Neira Ayuso
2020-11-14 1:42 ` Jakub Kicinski
2020-11-14 12:00 ` Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 4/9] net: 8021q: resolve forwarding path for vlan devices Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 5/9] bridge: resolve forwarding path for bridge devices Pablo Neira Ayuso
2020-11-12 0:53 ` Nikolay Aleksandrov
2020-11-13 15:40 ` Nikolay Aleksandrov
2020-11-11 19:37 ` [PATCH net-next,v3 6/9] netfilter: flowtable: use dev_fill_forward_path() to obtain ingress device Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 7/9] netfilter: flowtable: use dev_fill_forward_path() to obtain egress device Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 8/9] netfilter: flowtable: add vlan support Pablo Neira Ayuso
2020-11-11 19:37 ` [PATCH net-next,v3 9/9] selftests: netfilter: flowtable bridge and VLAN support Pablo Neira Ayuso
2020-11-14 1:55 ` [PATCH net-next,v3 0/9] netfilter: flowtable bridge and vlan enhancements Jakub Kicinski
2020-11-14 11:59 ` Pablo Neira Ayuso
2020-11-14 14:00 ` Tobias Waldekranz
2020-11-14 17:03 ` Jakub Kicinski
2020-11-16 22:18 ` Pablo Neira Ayuso
2020-11-16 22:28 ` Jakub Kicinski
2020-11-16 22:36 ` Pablo Neira Ayuso
2020-11-16 22:45 ` Jakub Kicinski
2020-11-16 22:56 ` Pablo Neira Ayuso
2020-11-21 12:31 ` Pablo Neira Ayuso
2020-11-21 18:15 ` Jakub Kicinski
2020-11-21 18:56 ` Pablo Neira Ayuso
2020-11-21 19:23 ` Jakub Kicinski
2020-11-22 11:33 ` Pablo Neira Ayuso
2020-11-16 22:31 ` Pablo Neira Ayuso [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201116223114.GA6905@salvia \
--to=pablo@netfilter.org \
--cc=davem@davemloft.net \
--cc=jeremy@azazel.net \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=razor@blackwall.org \
--cc=tobias@waldekranz.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).