2 * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * Based on Rusty Russell's IPv6 MASQUERADE target. Development of IPv6
9 * NAT funded by Astaro.
12 #include <linux/kernel.h>
13 #include <linux/atomic.h>
14 #include <linux/netdevice.h>
15 #include <linux/ipv6.h>
16 #include <linux/netfilter.h>
17 #include <linux/netfilter_ipv6.h>
18 #include <net/netfilter/nf_nat.h>
19 #include <net/addrconf.h>
21 #include <net/netfilter/ipv6/nf_nat_masquerade.h>
23 #define MAX_WORK_COUNT 16
25 static atomic_t v6_worker_count;
28 nf_nat_masquerade_ipv6(struct sk_buff *skb, const struct nf_nat_range2 *range,
29 const struct net_device *out)
31 enum ip_conntrack_info ctinfo;
32 struct nf_conn_nat *nat;
35 struct nf_nat_range2 newrange;
37 ct = nf_ct_get(skb, &ctinfo);
38 WARN_ON(!(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
39 ctinfo == IP_CT_RELATED_REPLY)));
41 if (ipv6_dev_get_saddr(nf_ct_net(ct), out,
42 &ipv6_hdr(skb)->daddr, 0, &src) < 0)
45 nat = nf_ct_nat_ext_add(ct);
47 nat->masq_index = out->ifindex;
49 newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
50 newrange.min_addr.in6 = src;
51 newrange.max_addr.in6 = src;
52 newrange.min_proto = range->min_proto;
53 newrange.max_proto = range->max_proto;
55 return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC);
57 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6);
59 static int device_cmp(struct nf_conn *ct, void *ifindex)
61 const struct nf_conn_nat *nat = nfct_nat(ct);
65 if (nf_ct_l3num(ct) != NFPROTO_IPV6)
67 return nat->masq_index == (int)(long)ifindex;
70 static int masq_device_event(struct notifier_block *this,
71 unsigned long event, void *ptr)
73 const struct net_device *dev = netdev_notifier_info_to_dev(ptr);
74 struct net *net = dev_net(dev);
76 if (event == NETDEV_DOWN)
77 nf_ct_iterate_cleanup_net(net, device_cmp,
78 (void *)(long)dev->ifindex, 0, 0);
83 static struct notifier_block masq_dev_notifier = {
84 .notifier_call = masq_device_event,
87 struct masq_dev_work {
88 struct work_struct work;
94 static int inet_cmp(struct nf_conn *ct, void *work)
96 struct masq_dev_work *w = (struct masq_dev_work *)work;
97 struct nf_conntrack_tuple *tuple;
99 if (!device_cmp(ct, (void *)(long)w->ifindex))
102 tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
104 return ipv6_addr_equal(&w->addr, &tuple->dst.u3.in6);
107 static void iterate_cleanup_work(struct work_struct *work)
109 struct masq_dev_work *w;
111 w = container_of(work, struct masq_dev_work, work);
113 nf_ct_iterate_cleanup_net(w->net, inet_cmp, (void *)w, 0, 0);
117 atomic_dec(&v6_worker_count);
118 module_put(THIS_MODULE);
121 /* ipv6 inet notifier is an atomic notifier, i.e. we cannot
124 * Unfortunately, nf_ct_iterate_cleanup_net can run for a long
125 * time if there are lots of conntracks and the system
126 * handles high softirq load, so it frequently calls cond_resched
127 * while iterating the conntrack table.
129 * So we defer nf_ct_iterate_cleanup_net walk to the system workqueue.
131 * As we can have 'a lot' of inet_events (depending on amount
132 * of ipv6 addresses being deleted), we also need to add an upper
133 * limit to the number of queued work items.
135 static int masq_inet6_event(struct notifier_block *this,
136 unsigned long event, void *ptr)
138 struct inet6_ifaddr *ifa = ptr;
139 const struct net_device *dev;
140 struct masq_dev_work *w;
143 if (event != NETDEV_DOWN ||
144 atomic_read(&v6_worker_count) >= MAX_WORK_COUNT)
147 dev = ifa->idev->dev;
148 net = maybe_get_net(dev_net(dev));
152 if (!try_module_get(THIS_MODULE))
155 w = kmalloc(sizeof(*w), GFP_ATOMIC);
157 atomic_inc(&v6_worker_count);
159 INIT_WORK(&w->work, iterate_cleanup_work);
160 w->ifindex = dev->ifindex;
163 schedule_work(&w->work);
168 module_put(THIS_MODULE);
174 static struct notifier_block masq_inet6_notifier = {
175 .notifier_call = masq_inet6_event,
178 static int masq_refcnt;
179 static DEFINE_MUTEX(masq_mutex);
181 int nf_nat_masquerade_ipv6_register_notifier(void)
185 mutex_lock(&masq_mutex);
186 /* check if the notifier is already set */
187 if (++masq_refcnt > 1)
190 ret = register_netdevice_notifier(&masq_dev_notifier);
194 ret = register_inet6addr_notifier(&masq_inet6_notifier);
198 mutex_unlock(&masq_mutex);
202 unregister_netdevice_notifier(&masq_dev_notifier);
206 mutex_unlock(&masq_mutex);
209 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier);
211 void nf_nat_masquerade_ipv6_unregister_notifier(void)
213 mutex_lock(&masq_mutex);
214 /* check if the notifier still has clients */
215 if (--masq_refcnt > 0)
218 unregister_inet6addr_notifier(&masq_inet6_notifier);
219 unregister_netdevice_notifier(&masq_dev_notifier);
221 mutex_unlock(&masq_mutex);
223 EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier);