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Date: Wed, 10 Sep 2014 17:10:41 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 24/25] netfilter: nf_nat: generalize IPv6 masquerading support for nf_tables
From: Arturo Borrero <arturo.borrero.glez@...il.com>
Let's refactor the code so we can reach the masquerade functionality
from outside the xt context (ie. nftables).
The patch includes the addition of an atomic counter to the masquerade
notifier: the stuff to be done by the notifier is the same for xt and
nftables. Therefore, only one notification handler is needed.
This factorization only involves IPv6; a similar patch exists to
handle IPv4.
Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@...il.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/ipv6/nf_nat_masquerade.h | 10 ++
net/ipv6/netfilter/Kconfig | 7 ++
net/ipv6/netfilter/Makefile | 1 +
net/ipv6/netfilter/ip6t_MASQUERADE.c | 76 +--------------
net/ipv6/netfilter/nf_nat_masquerade_ipv6.c | 120 ++++++++++++++++++++++++
5 files changed, 143 insertions(+), 71 deletions(-)
create mode 100644 include/net/netfilter/ipv6/nf_nat_masquerade.h
create mode 100644 net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
diff --git a/include/net/netfilter/ipv6/nf_nat_masquerade.h b/include/net/netfilter/ipv6/nf_nat_masquerade.h
new file mode 100644
index 0000000..0a13396
--- /dev/null
+++ b/include/net/netfilter/ipv6/nf_nat_masquerade.h
@@ -0,0 +1,10 @@
+#ifndef _NF_NAT_MASQUERADE_IPV6_H_
+#define _NF_NAT_MASQUERADE_IPV6_H_
+
+unsigned int
+nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range *range,
+ const struct net_device *out);
+void nf_nat_masquerade_ipv6_register_notifier(void);
+void nf_nat_masquerade_ipv6_unregister_notifier(void);
+
+#endif /* _NF_NAT_MASQUERADE_IPV6_H_ */
diff --git a/net/ipv6/netfilter/Kconfig b/net/ipv6/netfilter/Kconfig
index ac93df1..6c8cfec 100644
--- a/net/ipv6/netfilter/Kconfig
+++ b/net/ipv6/netfilter/Kconfig
@@ -246,8 +246,15 @@ config NF_NAT_IPV6
if NF_NAT_IPV6
+config NF_NAT_MASQUERADE_IPV6
+ tristate "IPv6 masquerade support"
+ help
+ This is the kernel functionality to provide NAT in the masquerade
+ flavour (automatic source address selection) for IPv6.
+
config IP6_NF_TARGET_MASQUERADE
tristate "MASQUERADE target support"
+ select NF_NAT_MASQUERADE_IPV6
help
Masquerading is a special case of NAT: all outgoing connections are
changed to seem to come from a particular interface's address, and
diff --git a/net/ipv6/netfilter/Makefile b/net/ipv6/netfilter/Makefile
index c0b2631..89a0bd7 100644
--- a/net/ipv6/netfilter/Makefile
+++ b/net/ipv6/netfilter/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_NF_CONNTRACK_IPV6) += nf_conntrack_ipv6.o
nf_nat_ipv6-y := nf_nat_l3proto_ipv6.o nf_nat_proto_icmpv6.o
obj-$(CONFIG_NF_NAT_IPV6) += nf_nat_ipv6.o
+obj-$(CONFIG_NF_NAT_MASQUERADE_IPV6) += nf_nat_masquerade_ipv6.o
# defrag
nf_defrag_ipv6-y := nf_defrag_ipv6_hooks.o nf_conntrack_reasm.o
diff --git a/net/ipv6/netfilter/ip6t_MASQUERADE.c b/net/ipv6/netfilter/ip6t_MASQUERADE.c
index 3e4e92d..7f9f45d 100644
--- a/net/ipv6/netfilter/ip6t_MASQUERADE.c
+++ b/net/ipv6/netfilter/ip6t_MASQUERADE.c
@@ -19,33 +19,12 @@
#include <net/netfilter/nf_nat.h>
#include <net/addrconf.h>
#include <net/ipv6.h>
+#include <net/netfilter/ipv6/nf_nat_masquerade.h>
static unsigned int
masquerade_tg6(struct sk_buff *skb, const struct xt_action_param *par)
{
- const struct nf_nat_range *range = par->targinfo;
- enum ip_conntrack_info ctinfo;
- struct in6_addr src;
- struct nf_conn *ct;
- struct nf_nat_range newrange;
-
- ct = nf_ct_get(skb, &ctinfo);
- NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
- ctinfo == IP_CT_RELATED_REPLY));
-
- if (ipv6_dev_get_saddr(dev_net(par->out), par->out,
- &ipv6_hdr(skb)->daddr, 0, &src) < 0)
- return NF_DROP;
-
- nfct_nat(ct)->masq_index = par->out->ifindex;
-
- newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
- newrange.min_addr.in6 = src;
- newrange.max_addr.in6 = src;
- newrange.min_proto = range->min_proto;
- newrange.max_proto = range->max_proto;
-
- return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
+ return nf_nat_masquerade_ipv6(skb, par->targinfo, par->out);
}
static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par)
@@ -57,48 +36,6 @@ static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par)
return 0;
}
-static int device_cmp(struct nf_conn *ct, void *ifindex)
-{
- const struct nf_conn_nat *nat = nfct_nat(ct);
-
- if (!nat)
- return 0;
- if (nf_ct_l3num(ct) != NFPROTO_IPV6)
- return 0;
- return nat->masq_index == (int)(long)ifindex;
-}
-
-static int masq_device_event(struct notifier_block *this,
- unsigned long event, void *ptr)
-{
- const struct net_device *dev = netdev_notifier_info_to_dev(ptr);
- struct net *net = dev_net(dev);
-
- if (event == NETDEV_DOWN)
- nf_ct_iterate_cleanup(net, device_cmp,
- (void *)(long)dev->ifindex, 0, 0);
-
- return NOTIFY_DONE;
-}
-
-static struct notifier_block masq_dev_notifier = {
- .notifier_call = masq_device_event,
-};
-
-static int masq_inet_event(struct notifier_block *this,
- unsigned long event, void *ptr)
-{
- struct inet6_ifaddr *ifa = ptr;
- struct netdev_notifier_info info;
-
- netdev_notifier_info_init(&info, ifa->idev->dev);
- return masq_device_event(this, event, &info);
-}
-
-static struct notifier_block masq_inet_notifier = {
- .notifier_call = masq_inet_event,
-};
-
static struct xt_target masquerade_tg6_reg __read_mostly = {
.name = "MASQUERADE",
.family = NFPROTO_IPV6,
@@ -115,17 +52,14 @@ static int __init masquerade_tg6_init(void)
int err;
err = xt_register_target(&masquerade_tg6_reg);
- if (err == 0) {
- register_netdevice_notifier(&masq_dev_notifier);
- register_inet6addr_notifier(&masq_inet_notifier);
- }
+ if (err == 0)
+ nf_nat_masquerade_ipv6_register_notifier();
return err;
}
static void __exit masquerade_tg6_exit(void)
{
- unregister_inet6addr_notifier(&masq_inet_notifier);
- unregister_netdevice_notifier(&masq_dev_notifier);
+ nf_nat_masquerade_ipv6_unregister_notifier();
xt_unregister_target(&masquerade_tg6_reg);
}
diff --git a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
new file mode 100644
index 0000000..7745609
--- /dev/null
+++ b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2011 Patrick McHardy <kaber@...sh.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Based on Rusty Russell's IPv6 MASQUERADE target. Development of IPv6
+ * NAT funded by Astaro.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/atomic.h>
+#include <linux/netdevice.h>
+#include <linux/ipv6.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/addrconf.h>
+#include <net/ipv6.h>
+#include <net/netfilter/ipv6/nf_nat_masquerade.h>
+
+unsigned int
+nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range *range,
+ const struct net_device *out)
+{
+ enum ip_conntrack_info ctinfo;
+ struct in6_addr src;
+ struct nf_conn *ct;
+ struct nf_nat_range newrange;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
+ ctinfo == IP_CT_RELATED_REPLY));
+
+ if (ipv6_dev_get_saddr(dev_net(out), out,
+ &ipv6_hdr(skb)->daddr, 0, &src) < 0)
+ return NF_DROP;
+
+ nfct_nat(ct)->masq_index = out->ifindex;
+
+ newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
+ newrange.min_addr.in6 = src;
+ newrange.max_addr.in6 = src;
+ newrange.min_proto = range->min_proto;
+ newrange.max_proto = range->max_proto;
+
+ return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6);
+
+static int device_cmp(struct nf_conn *ct, void *ifindex)
+{
+ const struct nf_conn_nat *nat = nfct_nat(ct);
+
+ if (!nat)
+ return 0;
+ if (nf_ct_l3num(ct) != NFPROTO_IPV6)
+ return 0;
+ return nat->masq_index == (int)(long)ifindex;
+}
+
+static int masq_device_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ const struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+ struct net *net = dev_net(dev);
+
+ if (event == NETDEV_DOWN)
+ nf_ct_iterate_cleanup(net, device_cmp,
+ (void *)(long)dev->ifindex, 0, 0);
+
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block masq_dev_notifier = {
+ .notifier_call = masq_device_event,
+};
+
+static int masq_inet_event(struct notifier_block *this,
+ unsigned long event, void *ptr)
+{
+ struct inet6_ifaddr *ifa = ptr;
+ struct netdev_notifier_info info;
+
+ netdev_notifier_info_init(&info, ifa->idev->dev);
+ return masq_device_event(this, event, &info);
+}
+
+static struct notifier_block masq_inet_notifier = {
+ .notifier_call = masq_inet_event,
+};
+
+static atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0);
+
+void nf_nat_masquerade_ipv6_register_notifier(void)
+{
+ /* check if the notifier is already set */
+ if (atomic_inc_return(&masquerade_notifier_refcount) > 1)
+ return;
+
+ register_netdevice_notifier(&masq_dev_notifier);
+ register_inet6addr_notifier(&masq_inet_notifier);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier);
+
+void nf_nat_masquerade_ipv6_unregister_notifier(void)
+{
+ /* check if the notifier still has clients */
+ if (atomic_dec_return(&masquerade_notifier_refcount) > 0)
+ return;
+
+ unregister_inet6addr_notifier(&masq_inet_notifier);
+ unregister_netdevice_notifier(&masq_dev_notifier);
+}
+EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@...sh.net>");
--
1.7.10.4
--
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