1 /* Redirect. Simple mapping which alters dst to a local IP address. */
2 /* (C) 1999-2001 Paul `Rusty' Russell
3 * (C) 2002-2004 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_ipv4/ip_nat_rule.h>
23 MODULE_LICENSE("GPL");
24 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
25 MODULE_DESCRIPTION("iptables REDIRECT target module");
30 #define DEBUGP(format, args...)
33 /* FIXME: Take multiple ranges --RR */
35 redirect_check(const char *tablename
,
38 unsigned int targinfosize
,
39 unsigned int hook_mask
)
41 const struct ip_nat_multi_range_compat
*mr
= targinfo
;
43 if (strcmp(tablename
, "nat") != 0) {
44 DEBUGP("redirect_check: bad table `%s'.\n", table
);
47 if (targinfosize
!= IPT_ALIGN(sizeof(*mr
))) {
48 DEBUGP("redirect_check: size %u.\n", targinfosize
);
51 if (hook_mask
& ~((1 << NF_IP_PRE_ROUTING
) | (1 << NF_IP_LOCAL_OUT
))) {
52 DEBUGP("redirect_check: bad hooks %x.\n", hook_mask
);
55 if (mr
->range
[0].flags
& IP_NAT_RANGE_MAP_IPS
) {
56 DEBUGP("redirect_check: bad MAP_IPS.\n");
59 if (mr
->rangesize
!= 1) {
60 DEBUGP("redirect_check: bad rangesize %u.\n", mr
->rangesize
);
67 redirect_target(struct sk_buff
**pskb
,
68 const struct net_device
*in
,
69 const struct net_device
*out
,
74 struct ip_conntrack
*ct
;
75 enum ip_conntrack_info ctinfo
;
77 const struct ip_nat_multi_range_compat
*mr
= targinfo
;
78 struct ip_nat_range newrange
;
80 IP_NF_ASSERT(hooknum
== NF_IP_PRE_ROUTING
81 || hooknum
== NF_IP_LOCAL_OUT
);
83 ct
= ip_conntrack_get(*pskb
, &ctinfo
);
84 IP_NF_ASSERT(ct
&& (ctinfo
== IP_CT_NEW
|| ctinfo
== IP_CT_RELATED
));
86 /* Local packets: make them go to loopback */
87 if (hooknum
== NF_IP_LOCAL_OUT
)
88 newdst
= htonl(0x7F000001);
90 struct in_device
*indev
;
91 struct in_ifaddr
*ifa
;
96 indev
= __in_dev_get_rcu((*pskb
)->dev
);
97 if (indev
&& (ifa
= indev
->ifa_list
))
98 newdst
= ifa
->ifa_local
;
105 /* Transfer from original range. */
106 newrange
= ((struct ip_nat_range
)
107 { mr
->range
[0].flags
| IP_NAT_RANGE_MAP_IPS
,
109 mr
->range
[0].min
, mr
->range
[0].max
});
111 /* Hand modified range to generic setup. */
112 return ip_nat_setup_info(ct
, &newrange
, hooknum
);
115 static struct ipt_target redirect_reg
= {
117 .target
= redirect_target
,
118 .checkentry
= redirect_check
,
122 static int __init
init(void)
124 return ipt_register_target(&redirect_reg
);
127 static void __exit
fini(void)
129 ipt_unregister_target(&redirect_reg
);