ns proc: Add support for the network namespace.

Implementing file descriptors for the network namespace
is simple and straight forward.

Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

3 files changed, 35 insertions, 0 deletions

diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 6ae9f07d59ee..dcbd483e9915 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -16,6 +16,9 @@
 
 
 static const struct proc_ns_operations *ns_entries[] = {
+#ifdef CONFIG_NET_NS
+        &netns_operations,
+#endif
 };
 
 static const struct file_operations ns_file_operations = {
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index a6d2c6da5e5a..62126ec6ede9 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -265,6 +265,7 @@ struct proc_ns_operations {
         void (*put)(void *ns);
         int (*install)(struct nsproxy *nsproxy, void *ns);
 };
+extern const struct proc_ns_operations netns_operations;
 
 union proc_op {
         int (*proc_get_link)(struct inode *, struct path *);
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 3f860261c5ee..bf7707e09a80 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -573,3 +573,34 @@ void unregister_pernet_device(struct pernet_operations *ops)
         mutex_unlock(&net_mutex);
 }
 EXPORT_SYMBOL_GPL(unregister_pernet_device);
+
+#ifdef CONFIG_NET_NS
+static void *netns_get(struct task_struct *task)
+{
+        struct net *net;
+        rcu_read_lock();
+        net = get_net(task->nsproxy->net_ns);
+        rcu_read_unlock();
+        return net;
+}
+
+static void netns_put(void *ns)
+{
+        put_net(ns);
+}
+
+static int netns_install(struct nsproxy *nsproxy, void *ns)
+{
+        put_net(nsproxy->net_ns);
+        nsproxy->net_ns = get_net(ns);
+        return 0;
+}
+
+const struct proc_ns_operations netns_operations = {
+        .name           = "net",
+        .type           = CLONE_NEWNET,
+        .get            = netns_get,
+        .put            = netns_put,
+        .install        = netns_install,
+};
+#endif