netfilter: make /proc/net/netfilter pernet

This patch makes this proc dentry pernet. So far only init_net
had a /proc/net/netfilter directory.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/net_namespace.h

@@ -17,6 +17,7 @@
 #include <net/netns/ipv6.h>
 #include <net/netns/sctp.h>
 #include <net/netns/dccp.h>
+#include <net/netns/netfilter.h>
 #include <net/netns/x_tables.h>
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 #include <net/netns/conntrack.h>
@@ -94,6 +95,7 @@ struct net {
 	struct netns_dccp	dccp;
 #endif
 #ifdef CONFIG_NETFILTER
+	struct netns_nf		nf;
 	struct netns_xt		xt;
 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
 	struct netns_ct		ct;

include/net/netns/netfilter.h

+#ifndef __NETNS_NETFILTER_H
+#define __NETNS_NETFILTER_H
+
+#include <linux/proc_fs.h>
+
+struct netns_nf {
+#if defined CONFIG_PROC_FS
+	struct proc_dir_entry *proc_netfilter;
+#endif
+};
+#endif

net/netfilter/core.c

@@ -281,6 +281,34 @@ struct proc_dir_entry *proc_net_netfilter;
 EXPORT_SYMBOL(proc_net_netfilter);
 #endif
 
+static int __net_init netfilter_net_init(struct net *net)
+{
+#ifdef CONFIG_PROC_FS
+	net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",
+						net->proc_net);
+	if (net_eq(net, &init_net)) {
+		if (!net->nf.proc_netfilter)
+			return -ENOMEM;
+		else
+			proc_net_netfilter = net->nf.proc_netfilter;
+	} else if (!net->nf.proc_netfilter) {
+		pr_err("cannot create netfilter proc entry");
+		return -ENOMEM;
+	}
+#endif
+	return 0;
+}
+
+static void __net_exit netfilter_net_exit(struct net *net)
+{
+	remove_proc_entry("netfilter", net->proc_net);
+}
+
+static struct pernet_operations netfilter_net_ops = {
+	.init = netfilter_net_init,
+	.exit = netfilter_net_exit,
+};
+
 void __init netfilter_init(void)
 {
 	int i, h;
@@ -289,11 +317,8 @@ void __init netfilter_init(void)
 			INIT_LIST_HEAD(&nf_hooks[i][h]);
 	}
 
-#ifdef CONFIG_PROC_FS
-	proc_net_netfilter = proc_mkdir("netfilter", init_net.proc_net);
-	if (!proc_net_netfilter)
+	if (register_pernet_subsys(&netfilter_net_ops) < 0)
 		panic("cannot create netfilter proc entry");
-#endif
 
 	if (netfilter_log_init() < 0)
 		panic("cannot initialize nf_log");