From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Tobias Waldekranz <tobias@waldekranz.com>,
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 23:36:15 +0100 [thread overview]
Message-ID: <20201116223615.GA6967@salvia> (raw)
In-Reply-To: <20201116142844.7c492fb6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Mon, Nov 16, 2020 at 02:28:44PM -0800, Jakub Kicinski wrote:
> On Mon, 16 Nov 2020 23:18:15 +0100 Pablo Neira Ayuso wrote:
> > On Sat, Nov 14, 2020 at 09:03:47AM -0800, Jakub Kicinski wrote:
> > > On Sat, 14 Nov 2020 15:00:03 +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?
> > >
> > > Indeed, 2 VMs A and B, talking to each other, A is _outside_ the
> > > system (reachable via eth0), B is inside (veth1). When A moves inside
> > > and gets its veth. Neither B's veth1 not eth0 will change state, so
> > > cache wouldn't get flushed, right?
> >
> > The flow tuple includes the input interface as part of the hash key,
> > so packets will not match the existing entries in the flowtable after
> > the topology update.
>
> To be clear - the input interface for B -> A traffic remains B.
> So if B was talking to A before A moved it will keep hitting
> the cached entry.
Yes, Traffic for B -> A still hits the cached entry.
> Are you saying A -> B traffic won't match so it will update the cache,
> since conntrack flows are bi-directional?
Yes, Traffic for A -> B won't match the flowtable entry, this will
update the cache.
next prev parent reply other threads:[~2020-11-16 22:36 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 [this message]
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
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