1 /* Redirect. Simple mapping which alters dst to a local IP address. */
2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/types.h>
12 #include <linux/timer.h>
13 #include <linux/module.h>
14 #include <linux/netfilter.h>
15 #include <linux/netdevice.h>
17 #include <linux/inetdevice.h>
18 #include <net/protocol.h>
19 #include <net/checksum.h>
20 #include <linux/netfilter_ipv4.h>
21 #include <linux/netfilter/x_tables.h>
22 #include <net/netfilter/nf_nat_rule.h>
24 MODULE_LICENSE("GPL");
25 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
26 MODULE_DESCRIPTION("iptables REDIRECT target module");
31 #define DEBUGP(format, args...)
34 /* FIXME: Take multiple ranges --RR */
36 redirect_check(const char *tablename
,
38 const struct xt_target
*target
,
40 unsigned int hook_mask
)
42 const struct nf_nat_multi_range_compat
*mr
= targinfo
;
44 if (mr
->range
[0].flags
& IP_NAT_RANGE_MAP_IPS
) {
45 DEBUGP("redirect_check: bad MAP_IPS.\n");
48 if (mr
->rangesize
!= 1) {
49 DEBUGP("redirect_check: bad rangesize %u.\n", mr
->rangesize
);
56 redirect_target(struct sk_buff
**pskb
,
57 const struct net_device
*in
,
58 const struct net_device
*out
,
60 const struct xt_target
*target
,
64 enum ip_conntrack_info ctinfo
;
66 const struct nf_nat_multi_range_compat
*mr
= targinfo
;
67 struct nf_nat_range newrange
;
69 NF_CT_ASSERT(hooknum
== NF_IP_PRE_ROUTING
70 || hooknum
== NF_IP_LOCAL_OUT
);
72 ct
= nf_ct_get(*pskb
, &ctinfo
);
73 NF_CT_ASSERT(ct
&& (ctinfo
== IP_CT_NEW
|| ctinfo
== IP_CT_RELATED
));
75 /* Local packets: make them go to loopback */
76 if (hooknum
== NF_IP_LOCAL_OUT
)
77 newdst
= htonl(0x7F000001);
79 struct in_device
*indev
;
80 struct in_ifaddr
*ifa
;
85 indev
= __in_dev_get_rcu((*pskb
)->dev
);
86 if (indev
&& (ifa
= indev
->ifa_list
))
87 newdst
= ifa
->ifa_local
;
94 /* Transfer from original range. */
95 newrange
= ((struct nf_nat_range
)
96 { mr
->range
[0].flags
| IP_NAT_RANGE_MAP_IPS
,
98 mr
->range
[0].min
, mr
->range
[0].max
});
100 /* Hand modified range to generic setup. */
101 return nf_nat_setup_info(ct
, &newrange
, hooknum
);
104 static struct xt_target redirect_reg
= {
107 .target
= redirect_target
,
108 .targetsize
= sizeof(struct nf_nat_multi_range_compat
),
110 .hooks
= (1 << NF_IP_PRE_ROUTING
) | (1 << NF_IP_LOCAL_OUT
),
111 .checkentry
= redirect_check
,
115 static int __init
ipt_redirect_init(void)
117 return xt_register_target(&redirect_reg
);
120 static void __exit
ipt_redirect_fini(void)
122 xt_unregister_target(&redirect_reg
);
125 module_init(ipt_redirect_init
);
126 module_exit(ipt_redirect_fini
);