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From:   Menglong Dong <menglong8.dong@gmail.com>
Date:   Sun, 20 Mar 2022 21:27:52 +0800
Message-ID: <CADxym3b3T0V0zHkN36vusvSNL=Tk+b_Ahy9Tj8=kKm_gmuRS3A@mail.gmail.com>
Subject: Re: [PATCH net-next v3 3/3] net: icmp: add reasons of the skb drops
 to icmp protocol
To:     David Ahern <dsahern@kernel.org>
Cc:     Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>, xeb@mail.ru,
        David Miller <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Menglong Dong <imagedong@tencent.com>,
        Eric Dumazet <edumazet@google.com>, Martin Lau <kafai@fb.com>,
        Talal Ahmad <talalahmad@google.com>,
        Kees Cook <keescook@chromium.org>,
        Alexander Lobakin <alobakin@pm.me>,
        Hao Peng <flyingpeng@tencent.com>,
        Mengen Sun <mengensun@tencent.com>, dongli.zhang@oracle.com,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        Biao Jiang <benbjiang@tencent.com>
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On Sat, Mar 19, 2022 at 6:33 AM David Ahern <dsahern@kernel.org> wrote:
>
> On 3/18/22 1:26 AM, Menglong Dong wrote:
> > Yeah, PTYPE seems not suitable. I mean that replace SKB_DROP_REASON_PTYPE_ABSENT
> > that is used in __netif_receive_skb_core() with L3_PROTO, which means no L3
> > protocol handler (or other device handler) is not found for the
> > packet. This seems more
> > friendly and not code based.
> >
> >>> And use SKB_DROP_REASON_L4_PROTO for the L4 protocol problem,
> >>> such as GRE version not supported, ICMP type not supported, etc.
> > Is this L4_PROTO followed by anyone?
>
> how about just a generic
>         SKB_DROP_REASON_UNHANDLED_PROTO  /* protocol not implemented
>                                           * or not supported
>                                           */
>
> in place of current PTYPE_ABSENT (so a rename to remove a Linux code
> reference), and then use it for no L3 protocol handler, no L4 protocol
> handler, version extensions etc. The instruction pointer to symbol gives
> the context of the unsupported protocol.

Yeah, I think it's a good idea :)

Thanks!
Menglong Dong