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From: Jakub Kicinski <kuba@kernel.org>
To: Victor Nogueira <victor@mojatatu.com>
Cc: davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
	jhs@mojatatu.com, jiri@resnulli.us, horms@kernel.org,
	yotam.gi@gmail.com, edragain@163.com, vega@nebusec.ai,
	netdev@vger.kernel.org
Subject: Re: [PATCH net] net/sched: act_ife: use mac_len for ingress header offset
Date: Tue, 11 Aug 2026 17:45:52 -0700	[thread overview]
Message-ID: <20260811174552.21d08728@kernel.org> (raw)
In-Reply-To: <20260810144201.1563259-1-victor@mojatatu.com>

On Mon, 10 Aug 2026 11:42:01 -0300 Victor Nogueira wrote:
> On ingress, the L2 header stripped from the frame is skb->mac_len, not
> skb->dev->hard_header_len. Use it for the skb_push/skb_pull offsets in
> tcf_ife_encode()/tcf_ife_decode() and the matching header length inside
> ife_encode()/ife_decode(). On egress keep hard_header_len.
> 
> For devices where hard_header_len differs from mac_len (e.g. PPP, which
> reports 4 vs 0), the previous code pushed/pulled the wrong amount and
> could hit skb_under_panic on ingress when headroom was tight.

Clashiko points out that act_ife operates on Ethernet headers
pretty explicitly. IOW we're fixing a crash in a case that
functionally won't work, anyway.

Should we not simply drop all the packets if they are are destined 
for a non ARPHRD_ETHER device?

      reply	other threads:[~2026-08-12  0:45 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-10 14:42 [PATCH net] net/sched: act_ife: use mac_len for ingress header offset Victor Nogueira
2026-08-12  0:45 ` Jakub Kicinski [this message]

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