[PATCH 01/10] NetTestSlave: remount sysfs in new net namespace

[Ondrej Lichtner]

From: Ondrej Lichtner <olichtne(a)redhat.com&gt;

Creating a new network namespace does not change the contents of the
sysfs filesystem which makes it unusable for network configuration
purposes. This patch fixes that by creating a new mount namespace and
remounting the sysfs filesystem.

This also means that we don't need to use iproute2 to create Bonding
interfaces anymore.

Signed-off-by: Ondrej Lichtner <olichtne(a)redhat.com&gt;
---
 lnst/Slave/NetConfigDevice.py | 28 +++++-----------------------
 lnst/Slave/NetTestSlave.py    | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/lnst/Slave/NetConfigDevice.py b/lnst/Slave/NetConfigDevice.py
index 338df67..86744db 100644
--- a/lnst/Slave/NetConfigDevice.py
+++ b/lnst/Slave/NetConfigDevice.py
@@ -14,8 +14,6 @@ jpirko(a)redhat.com (Jiri Pirko)
 import logging
 import re
 import sys
-from platform import release
-from distutils.version import LooseVersion
 from lnst.Common.ExecCmd import exec_cmd
 from lnst.Slave.NetConfigCommon import get_slaves, get_option, get_slave_option
 from lnst.Common.Utils import kmod_in_use, bool_it
@@ -88,16 +86,9 @@ class NetConfigDeviceBond(NetConfigDeviceGeneric):
     _moduleparams = "max_bonds=0"
 
     def _add_rm_bond(self, mark):
-        #3.10 works on rhel7, I didn't test which oldest version works...
-        if LooseVersion(release()) > LooseVersion('3.10'):
-            if mark == "+":
-                exec_cmd('ip link add %s type bond' %
self._dev_config["name"])
-            elif mark == "-":
-                exec_cmd('ip link del %s' % self._dev_config["name"])
-        else:
-            bond_masters = "/sys/class/net/bonding_masters"
-            exec_cmd('echo "%s%s" > %s' % (mark,
self._dev_config["name"],
-                                           bond_masters))
+        bond_masters = "/sys/class/net/bonding_masters"
+        exec_cmd('echo "%s%s" > %s' % (mark,
self._dev_config["name"],
+                                       bond_masters))
 
     def _get_bond_dir(self):
         return "/sys/class/net/%s/bonding" %
self._dev_config["name"]
@@ -123,20 +114,11 @@ class NetConfigDeviceBond(NetConfigDeviceGeneric):
             slave_dev = self._if_manager.get_mapped_device(slave_id)
             slave_conf = slave_dev.get_conf_dict()
             slave_name = slave_dev.get_name()
-            bond_name = self._dev_config["name"]
             if mark == "+":
                 slave_dev.down()
 
-            #3.10 works on rhel7, I didn't test which oldest version works...
-            if LooseVersion(release()) > LooseVersion('3.10'):
-                if mark == "+":
-                    exec_cmd('ip link set %s master %s' % (slave_name,
-                                                           bond_name))
-                elif mark == "-":
-                    exec_cmd('ip link set %s nomaster' % (slave_name))
-            else:
-                exec_cmd('echo "%s%s" > %s/slaves' % (mark,
slave_name,
-                                                      self._get_bond_dir()))
+            exec_cmd('echo "%s%s" > %s/slaves' % (mark, slave_name,
+                                                  self._get_bond_dir()))
 
     def configure(self):
         self._add_rm_bond("+")
diff --git a/lnst/Slave/NetTestSlave.py b/lnst/Slave/NetTestSlave.py
index 780cd9a..8db7b8f 100644
--- a/lnst/Slave/NetTestSlave.py
+++ b/lnst/Slave/NetTestSlave.py
@@ -402,9 +402,21 @@ class SlaveMethods:
             elif pid == 0:
                 #create new network namespace
                 libc_name = ctypes.util.find_library("c")
-                CLONE_NEWNET = 0x40000000 #from sched.h
+                #from sched.h
+                CLONE_NEWNET = 0x40000000
+                CLONE_NEWNS = 0x00020000
+                #based on ipnetns.c from the iproute2 project
+                MNT_DETACH = 0x00000002
+                MS_SLAVE = 1<<19
+                MS_REC = 16384
+
                 libc = ctypes.CDLL(libc_name)
                 libc.unshare(CLONE_NEWNET)
+                #based on ipnetns.c from the iproute2 project
+                libc.unshare(CLONE_NEWNS)
+                libc.mount("", "/", "none", MS_SLAVE |
MS_REC, 0)
+                libc.umount2("/sys", MNT_DETACH)
+                libc.mount(netns, "/sys", "sysfs", 0, 0)
 
                 #set ctl socket to pipe to main netns
                 self._server_handler.close_s_sock()
-- 
1.9.3