RFC net_cls for sys container

Hi guys,

Now, lxc created with veth can not be under control by cls_cgroup.

the former discussion:
http://lkml.indiana.edu/hypermail/linux/kernel/1312.1/00214.html

In short, because cls_cgroup relys classid attached to sock filter skb, but sock will be cleared inside dev_forward_skb() in veth_xmit().

so I add backup_classid in struct sk_buffer to save classid before dev_forward_skb(). In cls_cgroup_classify(), if skb->sk is NULL, we can try to restore classid form skb->bk_classid.

Libo Chen (4):
net: introduce bk_classid to struct sk_buff
cls_cgroup: introduce a helper: bk_cls_classid()
veth: backup classid befor switch net_ns
cls_cgroup: restore classid from skb->sk_classid

 drivers/net/veth.c       |  5 +++++
 include/linux/skbuff.h   |  3 +++
 include/net/cls_cgroup.h | 11 +++++++++++
 net/sched/cls_cgroup.c   |  8 ++++----
 4 files changed, 23 insertions(+), 4 deletions(-)