[CRIU] [PATCH 0/10 v2] Dump and restore nested network namespaces

[Andrei Vagin]

From: Andrei Vagin <avagin at virtuozzo.com>

This is an initial support for nested network namespaces.

It was implemented to handle systemd services with private networks:

"""
When PrivateNetwork=yes is set in the [Service] section of a systemd service
unit file, the processes run for the service will run in a private network
namespace whith a private loopback network interface, and no other network
devices.
"""

How it works:
* All network devices are restored in the root task.
* A process sets an required network namespace to restore a socket
* Processes sets their network namespaces after restoring all sockets (files)

Known issues:
* veth devices between network namespaces are not supported

v2: * fix commetns from Pavel
    * improve the test to check that all processes are not restored
      in one netns
    * drop patches with a new ioctl to get netns for unconnected and
      unbound sockets, because it is not in the upstream kernel.

Andrei Vagin (8):
  net: save network namespaces for sockets
  net: bind and listen a parasite socket for each network namespace
  net: allow to dump and restore more than one network namespace
  net: set a proper network namespace to create a socket
  net: rename pid into nsid for prepare_net_ns()
  files: split collect_fd on allocate_fd and handle_fd
  files: add a function to reopen fd as an unused fd
  zdtm: add a test for nested network namespaces

 criu/cr-restore.c               |  40 ++++++--
 criu/files.c                    |  82 ++++++++++++++--
 criu/include/files.h            |   3 +
 criu/include/libnetlink.h       |   5 +-
 criu/include/namespaces.h       |   4 +-
 criu/include/net.h              |   6 +-
 criu/include/parasite.h         |   2 +
 criu/include/sk-packet.h        |   2 +-
 criu/include/sockets.h          |  11 ++-
 criu/libnetlink.c               |  13 +--
 criu/namespaces.c               |   6 +-
 criu/net.c                      | 187 +++++++++++++++++++++++++++++++-----
 criu/parasite-syscall.c         |  22 +----
 criu/pstree.c                   |   4 +
 criu/sk-inet.c                  |  21 ++++-
 criu/sk-netlink.c               |  19 +++-
 criu/sk-packet.c                |  10 +-
 criu/sk-unix.c                  |  17 +++-
 criu/sockets.c                  |  70 ++++++++++----
 images/packet-sock.proto        |   1 +
 images/sk-inet.proto            |   1 +
 images/sk-netlink.proto         |   1 +
 images/sk-packet.proto          |   1 +
 images/sk-unix.proto            |   2 +
 test/zdtm/static/Makefile       |   1 +
 test/zdtm/static/netns_sub.c    | 203 ++++++++++++++++++++++++++++++++++++++++
 test/zdtm/static/netns_sub.desc |   1 +
 27 files changed, 630 insertions(+), 105 deletions(-)
 create mode 100644 test/zdtm/static/netns_sub.c
 create mode 100644 test/zdtm/static/netns_sub.desc

-- 
2.7.4