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/[email protected]/ 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
