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Date: Thu, 17 Apr 2025 16:12:13 +0200
From: Florian Westphal <fw@strlen.de>
To: Huajian Yang <huajianyang@asrmicro.com>
Cc: pablo@netfilter.org, kadlec@netfilter.org, razor@blackwall.org,
	idosch@nvidia.com, davem@davemloft.net, dsahern@kernel.org,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	horms@kernel.org, netfilter-devel@vger.kernel.org,
	coreteam@netfilter.org, bridge@lists.linux.dev,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: Move specific fragmented packet to slow_path
 instead of dropping it
Message-ID: <aAEMPbbOGZDRygwr@strlen.de>
References: <20250417092953.8275-1-huajianyang@asrmicro.com>
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In-Reply-To: <20250417092953.8275-1-huajianyang@asrmicro.com>

Huajian Yang <huajianyang@asrmicro.com> wrote:
> The config NF_CONNTRACK_BRIDGE will change the bridge forwarding for
> fragmented packets.
> 
> The original bridge does not know that it is a fragmented packet and
> forwards it directly, after NF_CONNTRACK_BRIDGE is enabled, function
> nf_br_ip_fragment and br_ip6_fragment will check the headroom.
> 
> In original br_forward, insufficient headroom of skb may indeed exist,
> but there's still a way to save the skb in the device driver after
> dev_queue_xmit.So droping the skb will change the original bridge
> forwarding in some cases.

Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system")
Reviewed-by: Florian Westphal <fw@strlen.de>

This should probably be routed via Pablo.

Pablo, feel free to route this via nf-next if you think its not an
urgent fix, its been like this since bridge conntrack was added.