Subject: patch netns-teach-network-device-kobjects-which-namespace-they-are-in.patch added to gregkh-2.6 tree

From: <[email-masked]>
Date: Thu, 20 May 2010 11:10:39 -0700

This is a note to let you know that I've just added the patch titled

    Subject: [PATCH 2/6] netns: Teach network device kobjects which namespace they are in.

to my gregkh-2.6 tree.  Its filename is

    netns-teach-network-device-kobjects-which-namespace-they-are-in.patch

This tree can be found at 
    http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/

>>From [email-masked]  Thu May 20 10:41:04 2010
From: "Eric W. Biederman" <[email-masked]>
Date: Tue,  4 May 2010 17:36:45 -0700
Subject: [PATCH 2/6] netns: Teach network device kobjects which namespace they are in.
To: Greg Kroah-Hartman <[email-masked]>
Cc: Kay Sievers <[email-masked]>, [email-masked], Tejun Heo <[email-masked]>, Cornelia Huck <[email-masked]>, Eric Dumazet <[email-masked]>, Benjamin LaHaise <[email-masked]>, Serge Hallyn <[email-masked]>, <[email-masked]>, David Miller <[email-masked]>, "Eric W. Biederman" <[email-masked]>
Message-ID: <[email-masked]>

From: Eric W. Biederman <[email-masked]>

The problem.  Network devices show up in sysfs and with the network
namespace active multiple devices with the same name can show up in
the same directory, ouch!

To avoid that problem and allow existing applications in network namespaces
to see the same interface that is currently presented in sysfs, this
patch enables the tagging directory support in sysfs.

By using the network namespace pointers as tags to separate out the
the sysfs directory entries we ensure that we don't have conflicts
in the directories and applications only see a limited set of
the network devices.

Signed-off-by: Eric W. Biederman <[email-masked]>
Acked-by: David S. Miller <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>

---
 include/linux/kobject.h |    1 +
 net/Kconfig             |    8 ++++++++
 net/core/net-sysfs.c    |   46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)

--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -142,6 +142,7 @@ extern const struct sysfs_ops kobj_sysfs
  */
 enum kobj_ns_type {
 	KOBJ_NS_TYPE_NONE = 0,
+	KOBJ_NS_TYPE_NET,
 	KOBJ_NS_TYPES
 };
 
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -45,6 +45,14 @@ config COMPAT_NETLINK_MESSAGES
 
 menu "Networking options"
 
+config NET_NS
+	bool "Network namespace support"
+	default n
+	depends on EXPERIMENTAL && NAMESPACES
+	help
+	  Allow user space to create what appear to be multiple instances
+	  of the network stack.
+
 source "net/packet/Kconfig"
 source "net/unix/Kconfig"
 source "net/xfrm/Kconfig"
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -14,7 +14,9 @@
 #include <linux/netdevice.h>
 #include <linux/if_arp.h>
 #include <linux/slab.h>
+#include <linux/nsproxy.h>
 #include <net/sock.h>
+#include <net/net_namespace.h>
 #include <linux/rtnetlink.h>
 #include <linux/wireless.h>
 #include <net/wext.h>
@@ -467,6 +469,37 @@ static struct attribute_group wireless_g
 };
 #endif
 
+static const void *net_current_ns(void)
+{
+	return current->nsproxy->net_ns;
+}
+
+static const void *net_initial_ns(void)
+{
+	return &init_net;
+}
+
+static const void *net_netlink_ns(struct sock *sk)
+{
+	return sock_net(sk);
+}
+
+static struct kobj_ns_type_operations net_ns_type_operations = {
+	.type = KOBJ_NS_TYPE_NET,
+	.current_ns = net_current_ns,
+	.netlink_ns = net_netlink_ns,
+	.initial_ns = net_initial_ns,
+};
+
+static void net_kobj_ns_exit(struct net *net)
+{
+	kobj_ns_exit(KOBJ_NS_TYPE_NET, net);
+}
+
+static struct pernet_operations sysfs_net_ops = {
+	.exit = net_kobj_ns_exit,
+};
+
 #endif /* CONFIG_SYSFS */
 
 #ifdef CONFIG_HOTPLUG
@@ -507,6 +540,13 @@ static void netdev_release(struct device
 	kfree((char *)dev - dev->padded);
 }
 
+static const void *net_namespace(struct device *d)
+{
+	struct net_device *dev;
+	dev = container_of(d, struct net_device, dev);
+	return dev_net(dev);
+}
+
 static struct class net_class = {
 	.name = "net",
 	.dev_release = netdev_release,
@@ -516,6 +556,8 @@ static struct class net_class = {
 #ifdef CONFIG_HOTPLUG
 	.dev_uevent = netdev_uevent,
 #endif
+	.ns_type = &net_ns_type_operations,
+	.namespace = net_namespace,
 };
 
 /* Delete sysfs entries but hold kobject reference until after all
@@ -588,5 +630,9 @@ void netdev_initialize_kobject(struct ne
 
 int netdev_kobject_init(void)
 {
+	kobj_ns_type_register(&net_ns_type_operations);
+#ifdef CONFIG_SYSFS
+	register_pernet_subsys(&sysfs_net_ops);
+#endif
 	return class_register(&net_class);
 }