[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>
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index a4ce5e8..2a19c5f 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -14,6 +14,7 @@
 #include <linux/seq_file.h>
 #include <linux/percpu.h>
 #include <linux/netdevice.h>
+#include <net/net_namespace.h>
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
 #endif
@@ -420,10 +421,10 @@
 		return ret;
 
 #ifdef CONFIG_PROC_FS
-	proc = proc_net_fops_create("nf_conntrack", 0440, &ct_file_ops);
+	proc = proc_net_fops_create(&init_net, "nf_conntrack", 0440, &ct_file_ops);
 	if (!proc) goto cleanup_init;
 
-	proc_stat = create_proc_entry("nf_conntrack", S_IRUGO, proc_net_stat);
+	proc_stat = create_proc_entry("nf_conntrack", S_IRUGO, init_net.proc_net_stat);
 	if (!proc_stat)
 		goto cleanup_proc;
 
@@ -444,9 +445,9 @@
  cleanup_proc_stat:
 #endif
 #ifdef CONFIG_PROC_FS
-	remove_proc_entry("nf_conntrack", proc_net_stat);
+	remove_proc_entry("nf_conntrack", init_net. proc_net_stat);
  cleanup_proc:
-	proc_net_remove("nf_conntrack");
+	proc_net_remove(&init_net, "nf_conntrack");
  cleanup_init:
 #endif /* CNFIG_PROC_FS */
 	nf_conntrack_cleanup();
@@ -459,8 +460,8 @@
 	unregister_sysctl_table(nf_ct_sysctl_header);
 #endif
 #ifdef CONFIG_PROC_FS
-	remove_proc_entry("nf_conntrack", proc_net_stat);
-	proc_net_remove("nf_conntrack");
+	remove_proc_entry("nf_conntrack", init_net.proc_net_stat);
+	proc_net_remove(&init_net, "nf_conntrack");
 #endif /* CNFIG_PROC_FS */
 	nf_conntrack_cleanup();
 }