netdev - Re: [PATCH net-next 1/7] openvswitch: Use inverted tuple in ovs_ct_find

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Date:   Mon, 6 Feb 2017 16:45:06 -0800
From:   Joe Stringer <joe@....org>
To:     Jarno Rajahalme <jarno@....org>
Cc:     netdev <netdev@...r.kernel.org>, David Miller <davem@...emloft.net>
Subject: Re: [PATCH net-next 1/7] openvswitch: Use inverted tuple in
 ovs_ct_find_existing() if NATted.

On 5 February 2017 at 14:28, David Miller <davem@...emloft.net> wrote:
> From: Jarno Rajahalme <jarno@....org>
> Date: Thu,  2 Feb 2017 17:10:00 -0800
>
>> This does not match either of the conntrack tuples above.  Normally
>> this does not matter, as the conntrack lookup was already done using
>> the tuple (B,A), but if the current packet does not match any flow in
>> the OVS datapath, the packet is sent to userspace via an upcall,
>> during which the packet's skb is freed, and the conntrack entry
>> pointer in the skb is lost.
>
> This is the real bug.
>
> If the metadata for a packet is important, as it obviously is here,
> then upcalls should preserve that metadata across the upcall.  This
> is exactly how NF_QUEUE handles this problem and so should OVS.

Looks like the patch #5 provides this preservation across upcall, so
this patch can be converted to use the key->ct.orig_* from that patch
instead of doing the invert.