The upstream commit, 71d8c47fc6
("netfilter: conntrack: introduce clash resolution on insertion race"),
sets allow_clash=true in the UDP/UDPLITE protocol handler
but does not set it in the generic protocol handler.
As a result, packets composed of connectionless protocols at each layer,
such as UDP over IP-in-IP, still drop packets due to conflicts during conntrack insertion.
To resolve this, this patch sets allow_clash in the nf_conntrack_l4proto_generic.
Signed-off-by: Yuto Hamaguchi <Hamaguchi.Yuto@da.MitsubishiElectric.co.jp>
Signed-off-by: Florian Westphal <fw@strlen.de>