netfilter: xt_qtaguid: fix ipv6 protocol lookup

When updating the stats for a given uid it would incorrectly assume
IPV4 and pick up the wrong protocol when IPV6.

Change-Id: Iea4a635012b4123bf7aa93809011b7b2040bb3d5
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_qtaguid: start tracking iface rx/tx at low level

qtaguid tracks the device stats by monitoring when it goes up and down,
then it gets the dev_stats().
But devs don't correctly report stats (either they don't count headers
symmetrically between rx/tx, or they count internal control messages).

Now qtaguid counts the rx/tx bytes/packets during raw:prerouting and
mangle:postrouting (nat is not available in ipv6).

The results are in
  /proc/net/xt_qtaguid/iface_stat_fmt
which outputs a format line (bash expansion):
  ifname  total_skb_{rx,tx}_{bytes,packets}

Added event counters for pre/post handling.
Added extra ctrl_*() pid/uid debugging.

Change-Id: Id84345d544ad1dd5f63e3842cab229e71d339297
Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: xt_IDLETIMER: Rename INTERFACE to LABEL in netlink notification.

Signed-off-by: Ashish Sharma <ashishsharma@google.com>
netfilter: xt_qtaguid: fix error exit that would keep a spinlock.

qtudev_open() could return with a uid_tag_data_tree_lock held
when an kzalloc(..., GFP_ATOMIC) would fail.
Very unlikely to get triggered AND survive the mayhem of running out of mem.

Signed-off-by: JP Abgrall <jpa@google.com>
netfilter: qtaguid: Don't BUG_ON if create_if_tag_stat fails

If create_if_tag_stat fails to allocate memory (GFP_ATOMIC) the
following will happen:

qtaguid: iface_stat: tag stat alloc failed
...
kernel BUG at xt_qtaguid.c:1482!

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>