[PATCH v2 0/1] UDP traceroute packets with no checksum

[Kevin Mitchell]

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@xxxxxxxxxx/

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