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Date:   Fri, 25 Feb 2022 08:48:00 -0700
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Subject: Re: [PATCH net-next v3 4/4] net: tun: track dropped skb via
 kfree_skb_reason()
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To:     Menglong Dong <menglong8.dong@gmail.com>, dongli.zhang@oracle.com
Cc:     andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
        daniel@iogearbox.net, davem@davemloft.net, edumazet@google.com,
        imagedong@tencent.com, joao.m.martins@oracle.com,
        joe.jin@oracle.com, kuba@kernel.org, linux-kernel@vger.kernel.org,
        mingo@redhat.com, netdev@vger.kernel.org, rostedt@goodmis.org
References: <edddb6f9-70d1-4fcf-5630-cbdfe175e8ee@oracle.com>
 <20220225055732.1830237-1-imagedong@tencent.com>
From:   David Ahern <dsahern@gmail.com>
In-Reply-To: <20220225055732.1830237-1-imagedong@tencent.com>
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On 2/24/22 10:57 PM, Menglong Dong wrote:
>>>
>>> For tun unique filters, how about using a shortened version of the ioctl
>>> name used to set the filter.
>>>
>>
>> Although TUN is widely used in virtualization environment, it is only one of
>> many drivers. I prefer to not introduce a reason that can be used only by a
>> specific driver.
>>
>> In order to make it more generic and more re-usable (e.g., perhaps people may
>> add ebpf filter to TAP driver as well), how about we create below reasons.
>>
>> SKB_DROP_REASON_DEV_FILTER,     /* dropped by filter attached to
>> 				 * or directly implemented by a
>> 				 * specific driver
>> 				 */
>> SKB_DROP_REASON_BPF_DEV,	/* dropped by bpf directly
>> 				 * attached to a specific device,
>> 				 * e.g., via TUNSETFILTEREBPF
>> 				 */
> 
> Aren't DEV_FILTER and BPF_DEV too generic? eBPF atached to netdev can
> be many kinds, such as XDP, TC, etc.

yes.

> 
> I think that use TAP_TXFILTER instaed of DEV_FILTER maybe better?
> and TAP_FILTER->BPF_DEV. Make them similar to the name in
> __tun_chr_ioctl() may be easier for user to understand.
> 

in this case given the unique attach points and API tap in the name
seems more appropriate