Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* Masquerade. Simple mapping which alters range to a local IP address |
| 2 | (depending on route). */ |
| 3 | |
| 4 | /* (C) 1999-2001 Paul `Rusty' Russell |
Jozsef Kadlecsik | 5b1158e | 2006-12-02 22:07:13 -0800 | [diff] [blame] | 5 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/types.h> |
Arnaldo Carvalho de Melo | 14c8502 | 2005-12-27 02:43:12 -0200 | [diff] [blame] | 13 | #include <linux/inetdevice.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | #include <linux/ip.h> |
| 15 | #include <linux/timer.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/netfilter.h> |
| 18 | #include <net/protocol.h> |
| 19 | #include <net/ip.h> |
| 20 | #include <net/checksum.h> |
Arnaldo Carvalho de Melo | 14c8502 | 2005-12-27 02:43:12 -0200 | [diff] [blame] | 21 | #include <net/route.h> |
Jozsef Kadlecsik | 5b1158e | 2006-12-02 22:07:13 -0800 | [diff] [blame] | 22 | #include <net/netfilter/nf_nat_rule.h> |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 23 | #include <linux/netfilter_ipv4.h> |
Jan Engelhardt | 6709dbb | 2007-02-07 15:11:19 -0800 | [diff] [blame] | 24 | #include <linux/netfilter/x_tables.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | |
| 26 | MODULE_LICENSE("GPL"); |
| 27 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
Jan Engelhardt | 2ae15b6 | 2008-01-14 23:42:28 -0800 | [diff] [blame] | 28 | MODULE_DESCRIPTION("Xtables: automatic-address SNAT"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | /* FIXME: Multiple targets. --RR */ |
Jan Engelhardt | 135367b | 2010-03-19 17:16:42 +0100 | [diff] [blame^] | 31 | static int masquerade_tg_check(const struct xt_tgchk_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | { |
Jan Engelhardt | af5d6dc | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 33 | const struct nf_nat_multi_range_compat *mr = par->targinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 36 | pr_debug("bad MAP_IPS.\n"); |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 37 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | } |
| 39 | if (mr->rangesize != 1) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 40 | pr_debug("bad rangesize %u\n", mr->rangesize); |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 41 | return false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | } |
Jan Engelhardt | e1931b7 | 2007-07-07 22:16:26 -0700 | [diff] [blame] | 43 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | } |
| 45 | |
| 46 | static unsigned int |
Jan Engelhardt | 7eb3558 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 47 | masquerade_tg(struct sk_buff *skb, const struct xt_target_param *par) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | { |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 49 | struct nf_conn *ct; |
Jozsef Kadlecsik | 5b1158e | 2006-12-02 22:07:13 -0800 | [diff] [blame] | 50 | struct nf_conn_nat *nat; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | enum ip_conntrack_info ctinfo; |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 52 | struct nf_nat_range newrange; |
| 53 | const struct nf_nat_multi_range_compat *mr; |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 54 | const struct rtable *rt; |
Al Viro | a61ced5 | 2006-09-26 21:27:54 -0700 | [diff] [blame] | 55 | __be32 newsrc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | |
Jan Engelhardt | 7eb3558 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 57 | NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | |
Herbert Xu | 3db05fe | 2007-10-15 00:53:15 -0700 | [diff] [blame] | 59 | ct = nf_ct_get(skb, &ctinfo); |
Jozsef Kadlecsik | 5b1158e | 2006-12-02 22:07:13 -0800 | [diff] [blame] | 60 | nat = nfct_nat(ct); |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 61 | |
Joe Perches | 3666ed1 | 2009-11-23 23:17:06 +0100 | [diff] [blame] | 62 | NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || |
| 63 | ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
Patrick McHardy | adcb5ad | 2005-09-13 13:49:15 -0700 | [diff] [blame] | 65 | /* Source address is 0.0.0.0 - locally generated packet that is |
| 66 | * probably not supposed to be masqueraded. |
| 67 | */ |
Jozsef Kadlecsik | 5b1158e | 2006-12-02 22:07:13 -0800 | [diff] [blame] | 68 | if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0) |
Patrick McHardy | adcb5ad | 2005-09-13 13:49:15 -0700 | [diff] [blame] | 69 | return NF_ACCEPT; |
| 70 | |
Jan Engelhardt | 7eb3558 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 71 | mr = par->targinfo; |
Eric Dumazet | 511c3f9 | 2009-06-02 05:14:27 +0000 | [diff] [blame] | 72 | rt = skb_rtable(skb); |
Jan Engelhardt | 7eb3558 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 73 | newsrc = inet_select_addr(par->out, rt->rt_gateway, RT_SCOPE_UNIVERSE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | if (!newsrc) { |
Jan Engelhardt | ff67e4e | 2010-03-19 21:08:16 +0100 | [diff] [blame] | 75 | pr_info("%s ate my IP address\n", par->out->name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | return NF_DROP; |
| 77 | } |
| 78 | |
Jan Engelhardt | 7eb3558 | 2008-10-08 11:35:19 +0200 | [diff] [blame] | 79 | nat->masq_index = par->out->ifindex; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | |
| 81 | /* Transfer from original range. */ |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 82 | newrange = ((struct nf_nat_range) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 83 | { mr->range[0].flags | IP_NAT_RANGE_MAP_IPS, |
| 84 | newsrc, newsrc, |
| 85 | mr->range[0].min, mr->range[0].max }); |
| 86 | |
| 87 | /* Hand modified range to generic setup. */ |
Patrick McHardy | cc01dcb | 2007-12-17 22:38:20 -0800 | [diff] [blame] | 88 | return nf_nat_setup_info(ct, &newrange, IP_NAT_MANIP_SRC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | } |
| 90 | |
Jan Engelhardt | 170b197 | 2007-07-07 22:17:36 -0700 | [diff] [blame] | 91 | static int |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 92 | device_cmp(struct nf_conn *i, void *ifindex) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | { |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 94 | const struct nf_conn_nat *nat = nfct_nat(i); |
Martin Josefsson | bbdc176 | 2007-01-04 12:16:54 -0800 | [diff] [blame] | 95 | |
| 96 | if (!nat) |
| 97 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | |
Florian Westphal | 17f2f52 | 2009-06-05 13:26:21 +0200 | [diff] [blame] | 99 | return nat->masq_index == (int)(long)ifindex; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | } |
| 101 | |
| 102 | static int masq_device_event(struct notifier_block *this, |
| 103 | unsigned long event, |
| 104 | void *ptr) |
| 105 | { |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame] | 106 | const struct net_device *dev = ptr; |
Alexey Dobriyan | b8b8063 | 2008-10-08 11:35:10 +0200 | [diff] [blame] | 107 | struct net *net = dev_net(dev); |
Eric W. Biederman | e9dc865 | 2007-09-12 13:02:17 +0200 | [diff] [blame] | 108 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | if (event == NETDEV_DOWN) { |
| 110 | /* Device was downed. Search entire table for |
| 111 | conntracks which were associated with that device, |
| 112 | and forget them. */ |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 113 | NF_CT_ASSERT(dev->ifindex != 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | |
Alexey Dobriyan | b8b8063 | 2008-10-08 11:35:10 +0200 | [diff] [blame] | 115 | nf_ct_iterate_cleanup(net, device_cmp, |
Alexey Dobriyan | 400dad3 | 2008-10-08 11:35:03 +0200 | [diff] [blame] | 116 | (void *)(long)dev->ifindex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | } |
| 118 | |
| 119 | return NOTIFY_DONE; |
| 120 | } |
| 121 | |
| 122 | static int masq_inet_event(struct notifier_block *this, |
| 123 | unsigned long event, |
| 124 | void *ptr) |
| 125 | { |
Denis V. Lunev | 6fc6862 | 2008-02-28 20:45:41 -0800 | [diff] [blame] | 126 | struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev; |
| 127 | return masq_device_event(this, event, dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | } |
| 129 | |
| 130 | static struct notifier_block masq_dev_notifier = { |
| 131 | .notifier_call = masq_device_event, |
| 132 | }; |
| 133 | |
| 134 | static struct notifier_block masq_inet_notifier = { |
| 135 | .notifier_call = masq_inet_event, |
| 136 | }; |
| 137 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 138 | static struct xt_target masquerade_tg_reg __read_mostly = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | .name = "MASQUERADE", |
Jan Engelhardt | ee999d8 | 2008-10-08 11:35:01 +0200 | [diff] [blame] | 140 | .family = NFPROTO_IPV4, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 141 | .target = masquerade_tg, |
Patrick McHardy | 587aa641 | 2007-03-14 16:37:25 -0700 | [diff] [blame] | 142 | .targetsize = sizeof(struct nf_nat_multi_range_compat), |
Patrick McHardy | 1d5cd90 | 2006-03-20 18:01:14 -0800 | [diff] [blame] | 143 | .table = "nat", |
Patrick McHardy | 6e23ae2 | 2007-11-19 18:53:30 -0800 | [diff] [blame] | 144 | .hooks = 1 << NF_INET_POST_ROUTING, |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 145 | .checkentry = masquerade_tg_check, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | .me = THIS_MODULE, |
| 147 | }; |
| 148 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 149 | static int __init masquerade_tg_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | { |
| 151 | int ret; |
| 152 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 153 | ret = xt_register_target(&masquerade_tg_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | |
| 155 | if (ret == 0) { |
| 156 | /* Register for device down reports */ |
| 157 | register_netdevice_notifier(&masq_dev_notifier); |
| 158 | /* Register IP address change reports */ |
| 159 | register_inetaddr_notifier(&masq_inet_notifier); |
| 160 | } |
| 161 | |
| 162 | return ret; |
| 163 | } |
| 164 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 165 | static void __exit masquerade_tg_exit(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | { |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 167 | xt_unregister_target(&masquerade_tg_reg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | unregister_netdevice_notifier(&masq_dev_notifier); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 169 | unregister_inetaddr_notifier(&masq_inet_notifier); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } |
| 171 | |
Jan Engelhardt | d3c5ee6 | 2007-12-04 23:24:03 -0800 | [diff] [blame] | 172 | module_init(masquerade_tg_init); |
| 173 | module_exit(masquerade_tg_exit); |