From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH v1 net-next 1/5] drop_monitor: import netnamespace framework
Date: Wed, 12 Jul 2017 10:45:52 -0700
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Cc: Neil Horman <nhorman@tuxdriver.com>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        martinbj2008 <martinbj2008@gmail.com>,
        David Miller <davem@davemloft.net>
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        <zhangjunweimartin@didichuxing.com>
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On Wed, Jul 12, 2017 at 10:08 AM, =E5=BC=A0=E5=86=9B=E4=BC=9F(=E5=9F=BA=E7=
=A1=80=E5=B9=B3=E5=8F=B0=E9=83=A8)
<zhangjunweimartin@didichuxing.com> wrote:
> about skb->sk
> it is used as supplementary when skb->dev is empty=EF=BC=8Csuch as netlin=
k message=E3=80=82
>
> +       if (skb->dev)
> +               net =3D dev_net(skb->dev);
> +       else if (skb->sk)
> +               net =3D sock_net(skb->sk);
> +       else
> +               return;

Check udp_set_dev_scratch().

Again, as Neil mentioned, the idea is arguable, it is actually harder to tr=
ace
skb's with your patch when they across netns'es.