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Commit | Line | Data |
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1da177e4 LT |
1 | /* Redirect. Simple mapping which alters dst to a local IP address. */ |
2 | /* (C) 1999-2001 Paul `Rusty' Russell | |
5b1158e9 | 3 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
1da177e4 LT |
4 | * |
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. | |
8 | */ | |
ff67e4e4 | 9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
1da177e4 LT |
10 | #include <linux/types.h> |
11 | #include <linux/ip.h> | |
12 | #include <linux/timer.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/netfilter.h> | |
15 | #include <linux/netdevice.h> | |
16 | #include <linux/if.h> | |
17 | #include <linux/inetdevice.h> | |
18 | #include <net/protocol.h> | |
19 | #include <net/checksum.h> | |
20 | #include <linux/netfilter_ipv4.h> | |
6709dbbb | 21 | #include <linux/netfilter/x_tables.h> |
5b1158e9 | 22 | #include <net/netfilter/nf_nat_rule.h> |
1da177e4 LT |
23 | |
24 | MODULE_LICENSE("GPL"); | |
25 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
2ae15b64 | 26 | MODULE_DESCRIPTION("Xtables: Connection redirection to localhost"); |
1da177e4 | 27 | |
1da177e4 | 28 | /* FIXME: Take multiple ranges --RR */ |
135367b8 | 29 | static int redirect_tg_check(const struct xt_tgchk_param *par) |
1da177e4 | 30 | { |
af5d6dc2 | 31 | const struct nf_nat_multi_range_compat *mr = par->targinfo; |
1da177e4 | 32 | |
1da177e4 | 33 | if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) { |
ff67e4e4 | 34 | pr_debug("bad MAP_IPS.\n"); |
d6b00a53 | 35 | return -EINVAL; |
1da177e4 LT |
36 | } |
37 | if (mr->rangesize != 1) { | |
ff67e4e4 | 38 | pr_debug("bad rangesize %u.\n", mr->rangesize); |
d6b00a53 | 39 | return -EINVAL; |
1da177e4 | 40 | } |
d6b00a53 | 41 | return 0; |
1da177e4 LT |
42 | } |
43 | ||
44 | static unsigned int | |
4b560b44 | 45 | redirect_tg(struct sk_buff *skb, const struct xt_action_param *par) |
1da177e4 | 46 | { |
587aa641 | 47 | struct nf_conn *ct; |
1da177e4 | 48 | enum ip_conntrack_info ctinfo; |
a144ea4b | 49 | __be32 newdst; |
7eb35586 | 50 | const struct nf_nat_multi_range_compat *mr = par->targinfo; |
587aa641 | 51 | struct nf_nat_range newrange; |
1da177e4 | 52 | |
7eb35586 JE |
53 | NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING || |
54 | par->hooknum == NF_INET_LOCAL_OUT); | |
1da177e4 | 55 | |
3db05fea | 56 | ct = nf_ct_get(skb, &ctinfo); |
587aa641 | 57 | NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED)); |
1da177e4 LT |
58 | |
59 | /* Local packets: make them go to loopback */ | |
7eb35586 | 60 | if (par->hooknum == NF_INET_LOCAL_OUT) |
1da177e4 LT |
61 | newdst = htonl(0x7F000001); |
62 | else { | |
63 | struct in_device *indev; | |
cd0bf2d7 | 64 | struct in_ifaddr *ifa; |
1da177e4 | 65 | |
cd0bf2d7 | 66 | newdst = 0; |
e905a9ed | 67 | |
cd0bf2d7 | 68 | rcu_read_lock(); |
3db05fea | 69 | indev = __in_dev_get_rcu(skb->dev); |
cd0bf2d7 PM |
70 | if (indev && (ifa = indev->ifa_list)) |
71 | newdst = ifa->ifa_local; | |
72 | rcu_read_unlock(); | |
1da177e4 | 73 | |
cd0bf2d7 PM |
74 | if (!newdst) |
75 | return NF_DROP; | |
1da177e4 LT |
76 | } |
77 | ||
78 | /* Transfer from original range. */ | |
587aa641 | 79 | newrange = ((struct nf_nat_range) |
1da177e4 LT |
80 | { mr->range[0].flags | IP_NAT_RANGE_MAP_IPS, |
81 | newdst, newdst, | |
82 | mr->range[0].min, mr->range[0].max }); | |
83 | ||
84 | /* Hand modified range to generic setup. */ | |
cc01dcbd | 85 | return nf_nat_setup_info(ct, &newrange, IP_NAT_MANIP_DST); |
1da177e4 LT |
86 | } |
87 | ||
d3c5ee6d | 88 | static struct xt_target redirect_tg_reg __read_mostly = { |
1da177e4 | 89 | .name = "REDIRECT", |
ee999d8b | 90 | .family = NFPROTO_IPV4, |
d3c5ee6d | 91 | .target = redirect_tg, |
587aa641 | 92 | .targetsize = sizeof(struct nf_nat_multi_range_compat), |
1d5cd909 | 93 | .table = "nat", |
6e23ae2a | 94 | .hooks = (1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT), |
d3c5ee6d | 95 | .checkentry = redirect_tg_check, |
1da177e4 LT |
96 | .me = THIS_MODULE, |
97 | }; | |
98 | ||
d3c5ee6d | 99 | static int __init redirect_tg_init(void) |
1da177e4 | 100 | { |
d3c5ee6d | 101 | return xt_register_target(&redirect_tg_reg); |
1da177e4 LT |
102 | } |
103 | ||
d3c5ee6d | 104 | static void __exit redirect_tg_exit(void) |
1da177e4 | 105 | { |
d3c5ee6d | 106 | xt_unregister_target(&redirect_tg_reg); |
1da177e4 LT |
107 | } |
108 | ||
d3c5ee6d JE |
109 | module_init(redirect_tg_init); |
110 | module_exit(redirect_tg_exit); |