Introduce a new revision for the set match with the counters support

The revision add the support of matching the packet/byte counters
if the set was defined with the extension. Also, a new flag is
introduced to suppress updating the packet/byte counters if required.

Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
ip[6]tables: Add locking to prevent concurrent instances

There have been numerous complaints and bug reports over the years when admins
attempt to run more than one instance of iptables simultaneously.  Currently
open bug reports which are related:

325: Parallel execution of the iptables is impossible
758: Retry iptables command on transient failure
764: Doing -Z twice in parallel breaks counters
822: iptables shows negative or other bad packet/byte counts

As Patrick notes in 325:  "Since this has been a problem people keep running
into, I'd suggest to simply add some locking to iptables to catch the most
common case."

I started looking into alternatives to add locking, and of course the most
common/obvious solution is to use a pidfile.  But this has various downsides,
such as if the application is terminated abnormally and the pidfile isn't
cleaned up.  And this also requires a writable filesystem.  Using a UNIX domain
socket file (e.g. in /var/run) has similar issues.

Starting in 2.2, Linux added support for abstract sockets.  These sockets
require no filesystem, and automatically disappear once the application
terminates.  This is the locking solution I chose to implement in ip[6]tables.
As an added bonus, since each network namespace has its own socket pool, an
ip[6]tables instance running in one namespace will not lock out an ip[6]tables
instance running in another namespace.  A filesystem approach would have
to recognize and handle multiple network namespaces.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
iptables: Fix connlabel.conf install location

As reported by Danny Rawlins in bug #828, connlabel.conf is
unconditionally installed in /etc/xtables instead of using
prefix set at configure time. Fix to use sysconfdir variable.

This closes bugzilla #828.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Merge branch 'stable'

Get c545933 iptables: Fix connlabel.conf install location