/*
* Copyright (c) 2011 Patrick McHardy <kaber@trash.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/netdevice.h>
#include <linux/ipv6.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/x_tables.h>
#include <net/netfilter/nf_nat.h>
#include <net/addrconf.h>
#include <net/ipv6.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);
}
static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par)
{
const struct nf_nat_range *range = par->targinfo;
if (range->flags & NF_NAT_RANGE_MAP_IPS)
return -EINVAL;
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 = ptr;
struct net *net = dev_net(dev);
if (event == NETDEV_DOWN)
nf_ct_iterate_cleanup(net, device_cmp,
(void *)(long)dev->ifindex);
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;
return masq_device_event(this, event, ifa->idev->dev);
}
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,
.checkentry = masquerade_tg6_checkentry,
.target = masquerade_tg6,
.targetsize = sizeof(struct nf_nat_range),
.table = "nat",
.hooks = 1 << NF_INET_POST_ROUTING,
.me = THIS_MODULE,
};
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);
}
return err;
}
static void __exit masquerade_tg6_exit(void)
{
unregister_inet6addr_notifier(&masq_inet_notifier);
unregister_netdevice_notifier(&masq_dev_notifier);
xt_unregister_target(&masquerade_tg6_reg);
}
module_init(masquerade_tg6_init);
module_exit(masquerade_tg6_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Xtables: automatic address SNAT");
