clat: enable PACKET_VNET_HDR on v6 ingress

We need the checksum information this 10-byte extra header provides.

Note: this must be merged in combination with a change to userspace
clatd to at least skip over the new 10 byte header (and increase
the read buffer size).

Test: TreeHugger, ping 1.1.1.1 on v6-only wifi
Bug: 265591307
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I35948a7ac463473300e45f37bc16b5b8d629d63c
1 file changed