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From: Kevin Mitchell <kevmitch@arista.com>
Date: Tue,  5 Apr 2022 16:51:15 -0700
Message-Id: <20220405235117.269511-1-kevmitch@arista.com>
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Subject: [Bridge] [PATCH v2 0/1] UDP traceroute packets with no checksum
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Cc: kevmitch@arista.com, Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>, netdev@vger.kernel.org, gal@nvidia.com, bridge@lists.linux-foundation.org, Florian Westphal <fw@strlen.de>, linux-kernel@vger.kernel.org, Jozsef Kadlecsik <kadlec@netfilter.org>, coreteam@netfilter.org, netfilter-devel@vger.kernel.org, Nikolay Aleksandrov <nikolay@nvidia.com>, Roopa Prabhu <roopa@nvidia.com>, Jakub Kicinski <kuba@kernel.org>, Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>, "David S. Miller" <davem@davemloft.net>, Pablo Neira Ayuso <pablo@netfilter.org>

This is v2 of https://lkml.org/lkml/2022/1/14/1060

That patch was discovered to cause problems with UDP tunnels as
described here:

https://lore.kernel.org/netdev/7eed8111-42d7-63e1-d289-346a596fc933@nvidia.com/

This version addresses the issue by instead explicitly handling zero UDP
checksum in the nf_reject_verify_csum() helper function.

Unlike the previous patch, this one only allows zero UDP checksum in
IPv4. I discovered that the non-netfilter IPv6 path would indeed drop
zero UDP checksum packets, so it's probably best to remain consistent.

-- 
2.35.1