[NETNS]: Create ipv6 devconf-s for namespaces

This is the core. Declare and register the pernet subsys for
addrconf. The init callback the will create the devconf-s.

The init_net will reuse the existing statically declared confs,
so that accessing them from inside the ipv6 code will still
work.

The register_pernet_subsys() is moved above the ipv6_add_dev()
call for loopback, because this function will need the
net->devconf_dflt pointer to be already set.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv6.h

@@ -28,5 +28,7 @@ struct netns_sysctl_ipv6 {
 
 struct netns_ipv6 {
 	struct netns_sysctl_ipv6 sysctl;
+	struct ipv6_devconf	*devconf_all;
+	struct ipv6_devconf	*devconf_dflt;
 };
 #endif

net/ipv6/addrconf.c

@@ -4135,6 +4135,70 @@ static void addrconf_sysctl_unregister(struct inet6_dev *idev)
 
 #endif
 
+static int addrconf_init_net(struct net *net)
+{
+	int err;
+	struct ipv6_devconf *all, *dflt;
+
+	err = -ENOMEM;
+	all = &ipv6_devconf;
+	dflt = &ipv6_devconf_dflt;
+
+	if (net != &init_net) {
+		all = kmemdup(all, sizeof(ipv6_devconf), GFP_KERNEL);
+		if (all == NULL)
+			goto err_alloc_all;
+
+		dflt = kmemdup(dflt, sizeof(ipv6_devconf_dflt), GFP_KERNEL);
+		if (dflt == NULL)
+			goto err_alloc_dflt;
+	}
+
+	net->ipv6.devconf_all = all;
+	net->ipv6.devconf_dflt = dflt;
+
+#ifdef CONFIG_SYSCTL
+	err = __addrconf_sysctl_register(net, "all", NET_PROTO_CONF_ALL,
+			NULL, all);
+	if (err < 0)
+		goto err_reg_all;
+
+	err = __addrconf_sysctl_register(net, "default", NET_PROTO_CONF_DEFAULT,
+			NULL, dflt);
+	if (err < 0)
+		goto err_reg_dflt;
+#endif
+	return 0;
+
+#ifdef CONFIG_SYSCTL
+err_reg_dflt:
+	__addrconf_sysctl_unregister(all);
+err_reg_all:
+	kfree(dflt);
+#endif
+err_alloc_dflt:
+	kfree(all);
+err_alloc_all:
+	return err;
+}
+
+static void addrconf_exit_net(struct net *net)
+{
+#ifdef CONFIG_SYSCTL
+	__addrconf_sysctl_unregister(net->ipv6.devconf_dflt);
+	__addrconf_sysctl_unregister(net->ipv6.devconf_all);
+#endif
+	if (net != &init_net) {
+		kfree(net->ipv6.devconf_dflt);
+		kfree(net->ipv6.devconf_all);
+	}
+}
+
+static struct pernet_operations addrconf_ops = {
+	.init = addrconf_init_net,
+	.exit = addrconf_exit_net,
+};
+
 /*
  *      Device notifier
  */
@@ -4167,6 +4231,8 @@ int __init addrconf_init(void)
 		return err;
 	}
 
+	register_pernet_subsys(&addrconf_ops);
+
 	/* The addrconf netdev notifier requires that loopback_dev
 	 * has it's ipv6 private information allocated and setup
 	 * before it can bring up and give link-local addresses
@@ -4190,7 +4256,7 @@ int __init addrconf_init(void)
 		err = -ENOMEM;
 	rtnl_unlock();
 	if (err)
-		return err;
+		goto errlo;
 
 	ip6_null_entry.u.dst.dev = init_net.loopback_dev;
 	ip6_null_entry.rt6i_idev = in6_dev_get(init_net.loopback_dev);
@@ -4218,16 +4284,11 @@ int __init addrconf_init(void)
 
 	ipv6_addr_label_rtnl_register();
 
-#ifdef CONFIG_SYSCTL
-	__addrconf_sysctl_register(&init_net, "all", NET_PROTO_CONF_ALL,
-			NULL, &ipv6_devconf);
-	__addrconf_sysctl_register(&init_net, "default", NET_PROTO_CONF_DEFAULT,
-			NULL, &ipv6_devconf_dflt);
-#endif
-
 	return 0;
 errout:
 	unregister_netdevice_notifier(&ipv6_dev_notf);
+errlo:
+	unregister_pernet_subsys(&addrconf_ops);
 
 	return err;
 }
@@ -4240,10 +4301,7 @@ void addrconf_cleanup(void)
 
 	unregister_netdevice_notifier(&ipv6_dev_notf);
 
-#ifdef CONFIG_SYSCTL
-	__addrconf_sysctl_unregister(&ipv6_devconf_dflt);
-	__addrconf_sysctl_unregister(&ipv6_devconf);
-#endif
+	unregister_pernet_subsys(&addrconf_ops);
 
 	rtnl_lock();