[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>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 9ab9d534fbac..78dd3443016c 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -103,6 +103,7 @@
 #include <linux/sysctl.h>
 #endif
 
+#include <net/net_namespace.h>
 #include <net/ip.h>
 #include <net/icmp.h>
 #include <net/route.h>
@@ -1400,7 +1401,7 @@ static const struct file_operations arp_seq_fops = {
 
 static int __init arp_proc_init(void)
 {
-        if (!proc_net_fops_create("arp", S_IRUGO, &arp_seq_fops))
+        if (!proc_net_fops_create(&init_net, "arp", S_IRUGO, &arp_seq_fops))
                 return -ENOMEM;
         return 0;
 }