net: l2tp: fix reversed udp6 checksum flags
authorWang Shanker <shankerwangmiao@gmail.com>
Thu, 28 Apr 2016 17:29:43 +0000 (01:29 +0800)
committerDavid S. Miller <davem@davemloft.net>
Sun, 1 May 2016 23:32:16 +0000 (19:32 -0400)
commit018f8258582381bcce484312f0e9ec2970d0383e
tree6688a00ddfbd30eaff6511d06f18d99fe5f55c94
parentf27337e16f2d0e52a8d05ea599ed13cd266ac291
net: l2tp: fix reversed udp6 checksum flags

This patch fixes a bug which causes the behavior of whether to ignore
udp6 checksum of udp6 encapsulated l2tp tunnel contrary to what
userspace program requests.

When the flag `L2TP_ATTR_UDP_ZERO_CSUM6_RX` is set by userspace, it is
expected that udp6 checksums of received packets of the l2tp tunnel
to create should be ignored. In `l2tp_netlink.c`:
`l2tp_nl_cmd_tunnel_create()`, `cfg.udp6_zero_rx_checksums` is set
according to the flag, and then passed to `l2tp_core.c`:
`l2tp_tunnel_create()` and then `l2tp_tunnel_sock_create()`. In
`l2tp_tunnel_sock_create()`, `udp_conf.use_udp6_rx_checksums` is set
the same to `cfg.udp6_zero_rx_checksums`. However, if we want the
checksum to be ignored, `udp_conf.use_udp6_rx_checksums` should be set
to `false`, i.e. be set to the contrary. Similarly, the same should be
done to `udp_conf.use_udp6_tx_checksums`.

Signed-off-by: Miao Wang <shankerwangmiao@gmail.com>
Acked-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/l2tp/l2tp_core.c