[NET]: Make /proc/net per network namespace

This patch makes /proc/net per network namespace.  It modifies the global
variables proc_net and proc_net_stat to be per network namespace.
The proc_net file helpers are modified to take a network namespace argument,
and all of their callers are fixed to pass &init_net for that argument.
This ensures that all of the /proc/net files are only visible and
usable in the initial network namespace until the code behind them
has been updated to be handle multiple network namespaces.

Making /proc/net per namespace is necessary as at least some files
in /proc/net depend upon the set of network devices which is per
network namespace, and even more files in /proc/net have contents
that are relevant to a single network namespace.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 24 insertions, 25 deletions

diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index cd13a78c5db..59646705f15 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -7,6 +7,7 @@
 #include <linux/magic.h>
 #include <asm/atomic.h>
 
+struct net;
 struct completion;
 
 /*
@@ -97,8 +98,6 @@ struct vmcore {
 
 extern struct proc_dir_entry proc_root;
 extern struct proc_dir_entry *proc_root_fs;
-extern struct proc_dir_entry *proc_net;
-extern struct proc_dir_entry *proc_net_stat;
 extern struct proc_dir_entry *proc_bus;
 extern struct proc_dir_entry *proc_root_driver;
 extern struct proc_dir_entry *proc_root_kcore;
@@ -192,36 +191,21 @@ static inline struct proc_dir_entry *create_proc_info_entry(const char *name,
         if (res) res->get_info=get_info;
         return res;
 }
- 
-static inline struct proc_dir_entry *proc_net_create(const char *name,
-        mode_t mode, get_info_t *get_info)
-{
-        return create_proc_info_entry(name,mode,proc_net,get_info);
-}
 
-static inline struct proc_dir_entry *proc_net_fops_create(const char *name,
-        mode_t mode, const struct file_operations *fops)
-{
-        struct proc_dir_entry *res = create_proc_entry(name, mode, proc_net);
-        if (res)
-                res->proc_fops = fops;
-        return res;
-}
-
-static inline void proc_net_remove(const char *name)
-{
-        remove_proc_entry(name,proc_net);
-}
+extern struct proc_dir_entry *proc_net_create(struct net *net,
+        const char *name, mode_t mode, get_info_t *get_info);
+extern struct proc_dir_entry *proc_net_fops_create(struct net *net,
+        const char *name, mode_t mode, const struct file_operations *fops);
+extern void proc_net_remove(struct net *net, const char *name);
 
 #else
 
 #define proc_root_driver NULL
-#define proc_net NULL
 #define proc_bus NULL
 
-#define proc_net_fops_create(name, mode, fops)  ({ (void)(mode), NULL; })
-#define proc_net_create(name, mode, info)       ({ (void)(mode), NULL; })
-static inline void proc_net_remove(const char *name) {}
+#define proc_net_fops_create(net, name, mode, fops)  ({ (void)(mode), NULL; })
+#define proc_net_create(net, name, mode, info)  ({ (void)(mode), NULL; })
+static inline void proc_net_remove(struct net *net, const char *name) {}
 
 static inline void proc_flush_task(struct task_struct *task) { }
 
@@ -281,6 +265,16 @@ static inline struct proc_dir_entry *PDE(const struct inode *inode)
         return PROC_I(inode)->pde;
 }
 
+static inline struct net *PDE_NET(struct proc_dir_entry *pde)
+{
+        return pde->parent->data;
+}
+
+static inline struct net *PROC_NET(const struct inode *inode)
+{
+        return PDE_NET(PDE(inode));
+}
+
 struct proc_maps_private {
         struct pid *pid;
         struct task_struct *task;
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 6344b77f81a..54724768134 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -8,6 +8,7 @@
 #include <linux/workqueue.h>
 #include <linux/list.h>
 
+struct proc_dir_entry;
 struct net {
         atomic_t                count;          /* To decided when the network
                                                  *  namespace should be freed.
@@ -17,6 +18,10 @@ struct net {
                                                  */
         struct list_head        list;           /* list of network namespaces */
         struct work_struct      work;           /* work struct for freeing */
+
+        struct proc_dir_entry   *proc_net;
+        struct proc_dir_entry   *proc_net_stat;
+        struct proc_dir_entry   *proc_net_root;
 };
 
 extern struct net init_net;