c346dca108
Introduce per-net_device inlines: dev_net(), dev_net_set(). Without CONFIG_NET_NS, no namespace other than &init_net exists. Let's explicitly define them to help compiler optimizations. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
190 lines
4.9 KiB
C
190 lines
4.9 KiB
C
/* Masquerade. Simple mapping which alters range to a local IP address
|
|
(depending on route). */
|
|
|
|
/* (C) 1999-2001 Paul `Rusty' Russell
|
|
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/inetdevice.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/module.h>
|
|
#include <linux/netfilter.h>
|
|
#include <net/protocol.h>
|
|
#include <net/ip.h>
|
|
#include <net/checksum.h>
|
|
#include <net/route.h>
|
|
#include <net/netfilter/nf_nat_rule.h>
|
|
#include <linux/netfilter_ipv4.h>
|
|
#include <linux/netfilter/x_tables.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
|
|
MODULE_DESCRIPTION("Xtables: automatic-address SNAT");
|
|
|
|
/* Lock protects masq region inside conntrack */
|
|
static DEFINE_RWLOCK(masq_lock);
|
|
|
|
/* FIXME: Multiple targets. --RR */
|
|
static bool
|
|
masquerade_tg_check(const char *tablename, const void *e,
|
|
const struct xt_target *target, void *targinfo,
|
|
unsigned int hook_mask)
|
|
{
|
|
const struct nf_nat_multi_range_compat *mr = targinfo;
|
|
|
|
if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) {
|
|
pr_debug("masquerade_check: bad MAP_IPS.\n");
|
|
return false;
|
|
}
|
|
if (mr->rangesize != 1) {
|
|
pr_debug("masquerade_check: bad rangesize %u\n", mr->rangesize);
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static unsigned int
|
|
masquerade_tg(struct sk_buff *skb, const struct net_device *in,
|
|
const struct net_device *out, unsigned int hooknum,
|
|
const struct xt_target *target, const void *targinfo)
|
|
{
|
|
struct nf_conn *ct;
|
|
struct nf_conn_nat *nat;
|
|
enum ip_conntrack_info ctinfo;
|
|
struct nf_nat_range newrange;
|
|
const struct nf_nat_multi_range_compat *mr;
|
|
const struct rtable *rt;
|
|
__be32 newsrc;
|
|
|
|
NF_CT_ASSERT(hooknum == NF_INET_POST_ROUTING);
|
|
|
|
ct = nf_ct_get(skb, &ctinfo);
|
|
nat = nfct_nat(ct);
|
|
|
|
NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED
|
|
|| ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY));
|
|
|
|
/* Source address is 0.0.0.0 - locally generated packet that is
|
|
* probably not supposed to be masqueraded.
|
|
*/
|
|
if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0)
|
|
return NF_ACCEPT;
|
|
|
|
mr = targinfo;
|
|
rt = skb->rtable;
|
|
newsrc = inet_select_addr(out, rt->rt_gateway, RT_SCOPE_UNIVERSE);
|
|
if (!newsrc) {
|
|
printk("MASQUERADE: %s ate my IP address\n", out->name);
|
|
return NF_DROP;
|
|
}
|
|
|
|
write_lock_bh(&masq_lock);
|
|
nat->masq_index = out->ifindex;
|
|
write_unlock_bh(&masq_lock);
|
|
|
|
/* Transfer from original range. */
|
|
newrange = ((struct nf_nat_range)
|
|
{ mr->range[0].flags | IP_NAT_RANGE_MAP_IPS,
|
|
newsrc, newsrc,
|
|
mr->range[0].min, mr->range[0].max });
|
|
|
|
/* Hand modified range to generic setup. */
|
|
return nf_nat_setup_info(ct, &newrange, IP_NAT_MANIP_SRC);
|
|
}
|
|
|
|
static int
|
|
device_cmp(struct nf_conn *i, void *ifindex)
|
|
{
|
|
const struct nf_conn_nat *nat = nfct_nat(i);
|
|
int ret;
|
|
|
|
if (!nat)
|
|
return 0;
|
|
|
|
read_lock_bh(&masq_lock);
|
|
ret = (nat->masq_index == (int)(long)ifindex);
|
|
read_unlock_bh(&masq_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int masq_device_event(struct notifier_block *this,
|
|
unsigned long event,
|
|
void *ptr)
|
|
{
|
|
const struct net_device *dev = ptr;
|
|
|
|
if (dev_net(dev) != &init_net)
|
|
return NOTIFY_DONE;
|
|
|
|
if (event == NETDEV_DOWN) {
|
|
/* Device was downed. Search entire table for
|
|
conntracks which were associated with that device,
|
|
and forget them. */
|
|
NF_CT_ASSERT(dev->ifindex != 0);
|
|
|
|
nf_ct_iterate_cleanup(device_cmp, (void *)(long)dev->ifindex);
|
|
}
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static int masq_inet_event(struct notifier_block *this,
|
|
unsigned long event,
|
|
void *ptr)
|
|
{
|
|
struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
|
|
return masq_device_event(this, event, dev);
|
|
}
|
|
|
|
static struct notifier_block masq_dev_notifier = {
|
|
.notifier_call = masq_device_event,
|
|
};
|
|
|
|
static struct notifier_block masq_inet_notifier = {
|
|
.notifier_call = masq_inet_event,
|
|
};
|
|
|
|
static struct xt_target masquerade_tg_reg __read_mostly = {
|
|
.name = "MASQUERADE",
|
|
.family = AF_INET,
|
|
.target = masquerade_tg,
|
|
.targetsize = sizeof(struct nf_nat_multi_range_compat),
|
|
.table = "nat",
|
|
.hooks = 1 << NF_INET_POST_ROUTING,
|
|
.checkentry = masquerade_tg_check,
|
|
.me = THIS_MODULE,
|
|
};
|
|
|
|
static int __init masquerade_tg_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = xt_register_target(&masquerade_tg_reg);
|
|
|
|
if (ret == 0) {
|
|
/* Register for device down reports */
|
|
register_netdevice_notifier(&masq_dev_notifier);
|
|
/* Register IP address change reports */
|
|
register_inetaddr_notifier(&masq_inet_notifier);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void __exit masquerade_tg_exit(void)
|
|
{
|
|
xt_unregister_target(&masquerade_tg_reg);
|
|
unregister_netdevice_notifier(&masq_dev_notifier);
|
|
unregister_inetaddr_notifier(&masq_inet_notifier);
|
|
}
|
|
|
|
module_init(masquerade_tg_init);
|
|
module_exit(masquerade_tg_exit);
|