netdev - Re: [PATCH net 1/2] openvswitch: support asymmetric conntrack

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Message-ID: <eb0bdc35-7f29-77c7-c013-e88f74772c24@6wind.com>
Date:   Tue, 12 Nov 2019 09:52:45 +0100
From:   Nicolas Dichtel <nicolas.dichtel@...nd.com>
To:     Aaron Conole <aconole@...hat.com>, netdev@...r.kernel.org
Cc:     Pravin B Shelar <pshelar@....org>,
        "David S . Miller" <davem@...emloft.net>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>, dev@...nvswitch.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net 1/2] openvswitch: support asymmetric conntrack

Le 08/11/2019 à 22:07, Aaron Conole a écrit :
> The openvswitch module shares a common conntrack and NAT infrastructure
> exposed via netfilter.  It's possible that a packet needs both SNAT and
> DNAT manipulation, due to e.g. tuple collision.  Netfilter can support
> this because it runs through the NAT table twice - once on ingress and
> again after egress.  The openvswitch module doesn't have such capability.
> 
> Like netfilter hook infrastructure, we should run through NAT twice to
> keep the symmetry.
> 
> Fixes: 05752523e565 ("openvswitch: Interface with NAT.")
> Signed-off-by: Aaron Conole <aconole@...hat.com>
In this case, ovs_ct_find_existing() won't be able to find the conntrack, right?
Inverting the tuple to find the conntrack doesn't work anymore with double NAT.
Am I wrong?


Regards,
Nicolas