Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* NETMAP - static NAT mapping of IP network addresses (1:1). |
| 2 | * The mapping can be applied to source (POSTROUTING), |
| 3 | * destination (PREROUTING), or both (with separate rules). |
| 4 | */ |
| 5 | |
| 6 | /* (C) 2000-2001 Svenning Soerensen <svenning@post5.tele.dk> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 as |
| 10 | * published by the Free Software Foundation. |
| 11 | */ |
| 12 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | #include <linux/ip.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/netdevice.h> |
| 16 | #include <linux/netfilter.h> |
| 17 | #include <linux/netfilter_ipv4.h> |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 18 | #include <linux/netfilter/x_tables.h> |
Jozsef Kadlecsik | 5b1158e | 2006-12-02 22:07:13 -0800 | [diff] [blame] | 19 | #include <net/netfilter/nf_nat_rule.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
| 21 | #define MODULENAME "NETMAP" |
| 22 | MODULE_LICENSE("GPL"); |
| 23 | MODULE_AUTHOR("Svenning Soerensen <svenning@post5.tele.dk>"); |
| 24 | MODULE_DESCRIPTION("iptables 1:1 NAT mapping of IP networks target"); |
| 25 | |
| 26 | #if 0 |
| 27 | #define DEBUGP printk |
| 28 | #else |
| 29 | #define DEBUGP(format, args...) |
| 30 | #endif |
| 31 | |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame^] | 32 | static bool |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | check(const char *tablename, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 34 | const void *e, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 35 | const struct xt_target *target, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | void *targinfo, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | unsigned int hook_mask) |
| 38 | { |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 39 | const struct nf_nat_multi_range_compat *mr = targinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | if (!(mr->range[0].flags & IP_NAT_RANGE_MAP_IPS)) { |
| 42 | DEBUGP(MODULENAME":check: bad MAP_IPS.\n"); |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame^] | 43 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | } |
| 45 | if (mr->rangesize != 1) { |
| 46 | DEBUGP(MODULENAME":check: bad rangesize %u.\n", mr->rangesize); |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame^] | 47 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | } |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame^] | 49 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | } |
| 51 | |
| 52 | static unsigned int |
| 53 | target(struct sk_buff **pskb, |
| 54 | const struct net_device *in, |
| 55 | const struct net_device *out, |
| 56 | unsigned int hooknum, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 57 | const struct xt_target *target, |
Patrick McHardy | fe1cb10 | 2006-08-22 00:35:47 -0700 | [diff] [blame] | 58 | const void *targinfo) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | { |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 60 | struct nf_conn *ct; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | enum ip_conntrack_info ctinfo; |
Al Viro | 6a19d61 | 2006-09-28 14:22:24 -0700 | [diff] [blame] | 62 | __be32 new_ip, netmask; |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 63 | const struct nf_nat_multi_range_compat *mr = targinfo; |
| 64 | struct nf_nat_range newrange; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 66 | NF_CT_ASSERT(hooknum == NF_IP_PRE_ROUTING |
Gary Wayne Smith | 000efe1 | 2005-08-14 17:33:24 -0700 | [diff] [blame] | 67 | || hooknum == NF_IP_POST_ROUTING |
| 68 | || hooknum == NF_IP_LOCAL_OUT); |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 69 | ct = nf_ct_get(*pskb, &ctinfo); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | |
| 71 | netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip); |
| 72 | |
Gary Wayne Smith | 000efe1 | 2005-08-14 17:33:24 -0700 | [diff] [blame] | 73 | if (hooknum == NF_IP_PRE_ROUTING || hooknum == NF_IP_LOCAL_OUT) |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 74 | new_ip = ip_hdr(*pskb)->daddr & ~netmask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | else |
Arnaldo Carvalho de Melo | eddc9ec | 2007-04-20 22:47:35 -0700 | [diff] [blame] | 76 | new_ip = ip_hdr(*pskb)->saddr & ~netmask; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | new_ip |= mr->range[0].min_ip & netmask; |
| 78 | |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 79 | newrange = ((struct nf_nat_range) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | { mr->range[0].flags | IP_NAT_RANGE_MAP_IPS, |
| 81 | new_ip, new_ip, |
| 82 | mr->range[0].min, mr->range[0].max }); |
| 83 | |
| 84 | /* Hand modified range to generic setup. */ |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 85 | return nf_nat_setup_info(ct, &newrange, hooknum); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | } |
| 87 | |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 88 | static struct xt_target target_module = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | .name = MODULENAME, |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 90 | .family = AF_INET, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 91 | .target = target, |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 92 | .targetsize = sizeof(struct nf_nat_multi_range_compat), |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 93 | .table = "nat", |
| 94 | .hooks = (1 << NF_IP_PRE_ROUTING) | (1 << NF_IP_POST_ROUTING) | |
| 95 | (1 << NF_IP_LOCAL_OUT), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | .checkentry = check, |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 97 | .me = THIS_MODULE |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | }; |
| 99 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 100 | static int __init ipt_netmap_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | { |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 102 | return xt_register_target(&target_module); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | } |
| 104 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 105 | static void __exit ipt_netmap_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | { |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 107 | xt_unregister_target(&target_module); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | } |
| 109 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 110 | module_init(ipt_netmap_init); |
| 111 | module_exit(ipt_netmap_fini); |