net: add ability to use tcp_repair_off from a restorer code

Use sys_setsockopt and declare a function in a header as "static inline"

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
tcp: unset TCP_REPAIR at the last moment after unlocking network (v2)

TCP_REPAIR should be droppet when a network is unlocked.
A network should be unlocked at the last moment, because
after this moment restore must not failed, otherwise a state of
a tcp connection can be changed and a state of one side in our image
will be invalid.

v2: use xremalloc instead of mmap and remmap

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
crtools: add ability to execute external scripts (v2)

Scripts are executed when external actions required.
CRTOOLS_SCRIPT_ACTION contains a required action.
If a script doesn't know a current action, it should exit with 0.

The first usecase will be lock/unlock network.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
tcp: split the list tcp_repair_sockets on rst and cpt parts

because here are two types of entries

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
util: add a function for running scripts

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
cd-dump: lock connection with iptables rules only in a current netns

For another netns we don't need to lock separate connections,
an external chanel can be locked.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
cr-dump: lock network before dump and unlock in case of errors

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
crtools: collect inet sockets to crtools

Early we moved prepare_shared() to a root task,
because several preparation actions should be executed
in a target namespace set (e.g.: ghost files).

TCP sockets are a subset of init sockets,
they should be unlocked before resume. It's convient to do
from crtools.
An image can't be read more than one time, because we want to
send it via network.

For this two reasons prepare_shared is spitted in two parts,
one for crtools and one for a root task.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
cr-restore: unlock connections at the last moment

Restore must not fail after unlocking connections.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
app-test: dump and restore a Linux Container

network-script.sh is used for locking and unlocking network in CT.

Here is an example of an LXC config:
lxc.console=none
lxc.utsname = test-lxc
lxc.network.type = veth
lxc.network.flags = up
lxc.network.link = br0
lxc.network.name = eth0
lxc.mount = /root/test-lxc/etc/fstab
lxc.rootfs = /root/test-lxc-root/

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
tcp: rename functions for unlocking tcp connections

One function is used on restoring and one is used on dumping,
so each function has own prefix rst or cpt.
The both functions have the same effect, so the main part of the names
is same and it describes "unlock_tcp_connections".

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
files-reg: Use global mutex to serialize ghost file creation

Otherwise there is a race between files with same names:

link(name -> ghost)                link(name->ghost)
open(name)
unlink(name)
                                   open(name) -> ENOENT

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
reg-files: No need for atomic @users

We're under lock anyway.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>