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Subject: Re: [PATCH net-next] net/sched: cls_flower: fix resetting of ether
 proto mask
To:     Boris Sukholitko <boris.sukholitko@broadcom.com>,
        Vladimir Oltean <olteanv@gmail.com>
Cc:     Vadym Kochan <vadym.kochan@plvision.eu>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Serhiy Boiko <serhiy.boiko@plvision.eu>,
        Volodymyr Mytnyk <volodymyr.mytnyk@plvision.eu>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        jiri@resnulli.us, idosch@idosch.org, ilya.lifshits@broadcom.com
References: <20210617161435.8853-1-vadym.kochan@plvision.eu>
 <20210617164155.li3fct6ad45a6j7h@skbuf>
 <20210617195102.h3bg6khvaogc2vwh@skbuf> <20210621083037.GA9665@builder>
From:   Jamal Hadi Salim <jhs@mojatatu.com>
Message-ID: <f18e6fee-8724-b246-adf9-53cc47f9520b@mojatatu.com>
Date:   Mon, 21 Jun 2021 10:04:41 -0400
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On 2021-06-21 4:32 a.m., Boris Sukholitko wrote:
> On Thu, Jun 17, 2021 at 10:51:02PM +0300, Vladimir Oltean wrote:
>> On Thu, Jun 17, 2021 at 07:41:55PM +0300, Vladimir Oltean wrote:
>>> On Thu, Jun 17, 2021 at 07:14:35PM +0300, Vadym Kochan wrote:
> 
> [snip excellent problem analysis]
> 
>> So maybe it is the flow dissector we need to fix, to make it give us an
>> additional pure EtherType if asked for, make tc-flower use that
>> dissector key instead, and then revert Jamal's user space patch, and we
>> should all install our tc filters as:
>>
>> tc filter add dev sw1p0 ingress handle 11 protocol all flower eth_type 0x8864 skip_hw action drop
>>
>> ?
> 
> I like this solution. To be more explicit, the plan becomes:
> 
> 1. Add FLOW_DISSECTOR_KEY_ETH_TYPE and struct flow_dissector_key_eth_type.
> 2. Have skb flow dissector use it.
> 3. Userspace does not set TCA_FLOWER_KEY_ETH_TYPE automagically
>     anymore. cls_flower takes basic.n_proto from struct tcf_proto.
> 4. Add eth_type to the userspace and use it to set TCA_FLOWER_KEY_ETH_TYPE
> 5. Existence of TCA_FLOWER_KEY_ETH_TYPE triggers new eth_type dissector.
> 
> IMHO this neatly solves non-vlan protocol match case.
> 
> What should we do with the VLANs then? Should we have vlan_pure_ethtype
> and cvlan_pure_ethtype as additional keys?
> 

I didnt see the original patch you sent until after it was applied
and the cursory 30 second glance didnt say much to me.

Vlans unfortunately are a speacial beast: You will have to retrieve
the proto differently.

Q: Was this always broken? Example look at Toke's change here:
commit d7bf2ebebc2bd61ab95e2a8e33541ef282f303d4

cheers,
jamal