net: Don't skip tun ifaddress

We're to support it.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
net: Support tun devices

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
net: Add dumping of tun/tap devices

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
files: Recognize tun files

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
net: Fixes for tun

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
net: tun -- Setup @sndbuf and @vnethdr

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
files: Fix file position conversion

There is no harm to set file positions to zero
for regular files, but when file refers to a
special device such as tun, we don't need criu
to set position here. So simply pass predefined
value which make criu happy.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>