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Subject: Re: [PATCH bpf-next V3 4/6] bpf: make it possible to identify BPF
 redirected SKBs
To:     Jesper Dangaard Brouer <brouer@redhat.com>, bpf@vger.kernel.org
Cc:     netdev@vger.kernel.org, Daniel Borkmann <borkmann@iogearbox.net>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        maze@google.com, lmb@cloudflare.com, shaun@tigera.io,
        Lorenzo Bianconi <lorenzo@kernel.org>, marek@cloudflare.com,
        John Fastabend <john.fastabend@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>, eyal.birger@gmail.com
References: <160216609656.882446.16642490462568561112.stgit@firesoul>
 <160216615767.882446.7384364280837100311.stgit@firesoul>
From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <40d7af61-6840-5473-79d7-ea935f6889f4@iogearbox.net>
Date:   Fri, 9 Oct 2020 18:47:45 +0200
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On 10/8/20 4:09 PM, Jesper Dangaard Brouer wrote:
> This change makes it possible to identify SKBs that have been redirected
> by TC-BPF (cls_act). This is needed for a number of cases.
> 
> (1) For collaborating with driver ifb net_devices.
> (2) For avoiding starting generic-XDP prog on TC ingress redirect.
> 
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>

Not sure if anyone actually cares about ifb devices, but my worry is that the
generic XDP vs tc interaction has been as-is for quite some time so this change
in behavior could break in the wild.