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Date: Mon, 23 Feb 2026 07:49:52 +0100
From: Florian Westphal <fw@strlen.de>
To: Eric Woudstra <ericwouds@gmail.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>, Phil Sutter <phil@nwl.cc>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Simon Horman <horms@kernel.org>, netfilter-devel@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH RFC v1 nf-next] netfilter: nf_flow_table_ip: Introduce
 nf_flow_vlan_push()
Message-ID: <aZv4kLUYBSzbWIxO@strlen.de>
References: <20260222155251.76886-1-ericwouds@gmail.com>
 <aZs8atSEZTjkzzQ3@strlen.de>
 <a4af5ff8-7aff-454d-8990-2922f1b9bbf3@gmail.com>
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In-Reply-To: <a4af5ff8-7aff-454d-8990-2922f1b9bbf3@gmail.com>

Eric Woudstra <ericwouds@gmail.com> wrote:
> I have run into this, when testing my branch for implementing the
> bridge-fastpath, not in the forward-fastpath. But anyway, no matter how
> packets are handled in the original path (forwarding or bridged), once
> going through the fastpath it would not matter, so it is broken in any
> fastpath.

Agree, it cannot work as-is.

> > Ok, I see, this opencodes a variant of skb_vlan_push().
> > Would it be possible to correct skb->data so it points to the mac header
> > temporarily?  skb->data always points to network header so this cannot
> > have worked, ever.
> 
> The code here for the inner header is an almost exact copy of
> nf_flow_pppoe_push(), which was also implemented at the same time.

Ah, I see.  Makes sense to me.

What aobut this:
Wait for a day or so to give others to provide feedback. If no more
comments, re-send this patch, targetting nf.git, and amend the commit
message to mention that the new function is closedly modelled on
existing nf_flow_pppoe_push().

Makes sense to you?