netdev - Re: [net-next 08/15] net/mlx5e: CT: Preparation for offloading +trk+new ct rules

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Message-ID: <218258b2-3a86-2d87-dfc6-8b3c1e274b26@nvidia.com>
Date:   Sun, 10 Jan 2021 09:52:55 +0200
From:   Roi Dayan <roid@...dia.com>
To:     Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
        Saeed Mahameed <saeed@...nel.org>
CC:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, <netdev@...r.kernel.org>,
        Paul Blakey <paulb@...dia.com>,
        Saeed Mahameed <saeedm@...dia.com>, Oz Shlomo <ozsh@...dia.com>
Subject: Re: [net-next 08/15] net/mlx5e: CT: Preparation for offloading
 +trk+new ct rules



On 2021-01-10 9:45 AM, Roi Dayan wrote:
> 
> 
> On 2021-01-08 11:48 PM, Marcelo Ricardo Leitner wrote:
>> Hi,
>>
>> On Thu, Jan 07, 2021 at 09:30:47PM -0800, Saeed Mahameed wrote:
>>> From: Roi Dayan <roid@...dia.com>
>>>
>>> Connection tracking associates the connection state per packet. The
>>> first packet of a connection is assigned with the +trk+new state. The
>>> connection enters the established state once a packet is seen on the
>>> other direction.
>>>
>>> Currently we offload only the established flows. However, UDP traffic
>>> using source port entropy (e.g. vxlan, RoCE) will never enter the
>>> established state. Such protocols do not require stateful processing,
>>> and therefore could be offloaded.
>>
>> If it doesn't require stateful processing, please enlight me on why
>> conntrack is being used in the first place. What's the use case here?
>>
> 
> The use case for example is when we have vxlan traffic but we do
> conntrack on the inner packet (rules on the physical port) so
> we never get established but on miss we can still offload as normal
> vxlan traffic.
> 

my mistake about "inner packet". we do CT on the underlay network, i.e.
the outer header.

>>>
>>> The change in the model is that a miss on the CT table will be forwarded
>>> to a new +trk+new ct table and a miss there will be forwarded to the 
>>> slow
>>> path table.
>>
>> AFAICU this new +trk+new ct table is a wildcard match on sport with
>> specific dports. Also AFAICU, such entries will not be visible to the
>> userspace then. Is this right?
>>
>>    Marcelo
>>
> 
> right.