This changes offload setting behaviour to what I think is correct:
- offloads set via ethtool mean what admin wants to use (by default
he wants 'em all)
- offloads set via ioctl() mean what userspace is expecting to get
(this limits which admin wishes are granted)
- TUN_NOCHECKSUM is ignored, as it might cause broken packets when
forwarded (ip_summed == CHECKSUM_UNNECESSARY means that checksum
was verified, not that it can be ignored)
If TUN_NOCHECKSUM is implemented, it should set skb->csum_* and
skb->ip_summed (= CHECKSUM_PARTIAL) for known protocols and let others
be verified by kernel when necessary.
TUN_NOCHECKSUM handling was introduced by commit
f43798c276:
tun: Allow GSO using virtio_net_hdr
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
8825537521