[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/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c
index 702d94d..cb5e61a 100644
--- a/net/ipv4/netfilter/ip_queue.c
+++ b/net/ipv4/netfilter/ip_queue.c
@@ -24,6 +24,7 @@
 #include <linux/proc_fs.h>
 #include <linux/security.h>
 #include <linux/mutex.h>
+#include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/route.h>
 
@@ -674,7 +675,7 @@
 		goto cleanup_netlink_notifier;
 	}
 
-	proc = proc_net_create(IPQ_PROC_FS_NAME, 0, ipq_get_info);
+	proc = proc_net_create(&init_net, IPQ_PROC_FS_NAME, 0, ipq_get_info);
 	if (proc)
 		proc->owner = THIS_MODULE;
 	else {
@@ -695,8 +696,7 @@
 cleanup_sysctl:
 	unregister_sysctl_table(ipq_sysctl_header);
 	unregister_netdevice_notifier(&ipq_dev_notifier);
-	proc_net_remove(IPQ_PROC_FS_NAME);
-
+	proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
 cleanup_ipqnl:
 	sock_release(ipqnl->sk_socket);
 	mutex_lock(&ipqnl_mutex);
@@ -715,7 +715,7 @@
 
 	unregister_sysctl_table(ipq_sysctl_header);
 	unregister_netdevice_notifier(&ipq_dev_notifier);
-	proc_net_remove(IPQ_PROC_FS_NAME);
+	proc_net_remove(&init_net, IPQ_PROC_FS_NAME);
 
 	sock_release(ipqnl->sk_socket);
 	mutex_lock(&ipqnl_mutex);