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Commit | Line | Data |
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1da177e4 LT |
1 | /* Masquerade. Simple mapping which alters range to a local IP address |
2 | (depending on route). */ | |
3 | ||
4 | /* (C) 1999-2001 Paul `Rusty' Russell | |
5b1158e9 | 5 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
1da177e4 LT |
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 | */ | |
ff67e4e4 | 11 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
1da177e4 | 12 | #include <linux/types.h> |
14c85021 | 13 | #include <linux/inetdevice.h> |
1da177e4 LT |
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> | |
14c85021 | 21 | #include <net/route.h> |
5b1158e9 | 22 | #include <net/netfilter/nf_nat_rule.h> |
587aa641 | 23 | #include <linux/netfilter_ipv4.h> |
6709dbbb | 24 | #include <linux/netfilter/x_tables.h> |
1da177e4 LT |
25 | |
26 | MODULE_LICENSE("GPL"); | |
27 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
2ae15b64 | 28 | MODULE_DESCRIPTION("Xtables: automatic-address SNAT"); |
1da177e4 | 29 | |
1da177e4 | 30 | /* FIXME: Multiple targets. --RR */ |
135367b8 | 31 | static int masquerade_tg_check(const struct xt_tgchk_param *par) |
1da177e4 | 32 | { |
af5d6dc2 | 33 | const struct nf_nat_multi_range_compat *mr = par->targinfo; |
1da177e4 | 34 | |
1da177e4 | 35 | if (mr->range[0].flags & IP_NAT_RANGE_MAP_IPS) { |
ff67e4e4 | 36 | pr_debug("bad MAP_IPS.\n"); |
d6b00a53 | 37 | return -EINVAL; |
1da177e4 LT |
38 | } |
39 | if (mr->rangesize != 1) { | |
ff67e4e4 | 40 | pr_debug("bad rangesize %u\n", mr->rangesize); |
d6b00a53 | 41 | return -EINVAL; |
1da177e4 | 42 | } |
d6b00a53 | 43 | return 0; |
1da177e4 LT |
44 | } |
45 | ||
46 | static unsigned int | |
4b560b44 | 47 | masquerade_tg(struct sk_buff *skb, const struct xt_action_param *par) |
1da177e4 | 48 | { |
587aa641 | 49 | struct nf_conn *ct; |
5b1158e9 | 50 | struct nf_conn_nat *nat; |
1da177e4 | 51 | enum ip_conntrack_info ctinfo; |
587aa641 PM |
52 | struct nf_nat_range newrange; |
53 | const struct nf_nat_multi_range_compat *mr; | |
a47362a2 | 54 | const struct rtable *rt; |
a61ced5d | 55 | __be32 newsrc; |
1da177e4 | 56 | |
7eb35586 | 57 | NF_CT_ASSERT(par->hooknum == NF_INET_POST_ROUTING); |
1da177e4 | 58 | |
3db05fea | 59 | ct = nf_ct_get(skb, &ctinfo); |
5b1158e9 | 60 | nat = nfct_nat(ct); |
587aa641 | 61 | |
3666ed1c JP |
62 | NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || |
63 | ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)); | |
1da177e4 | 64 | |
adcb5ad1 PM |
65 | /* Source address is 0.0.0.0 - locally generated packet that is |
66 | * probably not supposed to be masqueraded. | |
67 | */ | |
5b1158e9 | 68 | if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip == 0) |
adcb5ad1 PM |
69 | return NF_ACCEPT; |
70 | ||
7eb35586 | 71 | mr = par->targinfo; |
511c3f92 | 72 | rt = skb_rtable(skb); |
7eb35586 | 73 | newsrc = inet_select_addr(par->out, rt->rt_gateway, RT_SCOPE_UNIVERSE); |
1da177e4 | 74 | if (!newsrc) { |
ff67e4e4 | 75 | pr_info("%s ate my IP address\n", par->out->name); |
1da177e4 LT |
76 | return NF_DROP; |
77 | } | |
78 | ||
7eb35586 | 79 | nat->masq_index = par->out->ifindex; |
1da177e4 LT |
80 | |
81 | /* Transfer from original range. */ | |
587aa641 | 82 | newrange = ((struct nf_nat_range) |
1da177e4 LT |
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. */ | |
cc01dcbd | 88 | return nf_nat_setup_info(ct, &newrange, IP_NAT_MANIP_SRC); |
1da177e4 LT |
89 | } |
90 | ||
170b197c | 91 | static int |
587aa641 | 92 | device_cmp(struct nf_conn *i, void *ifindex) |
1da177e4 | 93 | { |
a47362a2 | 94 | const struct nf_conn_nat *nat = nfct_nat(i); |
bbdc176a MJ |
95 | |
96 | if (!nat) | |
97 | return 0; | |
1da177e4 | 98 | |
17f2f52b | 99 | return nat->masq_index == (int)(long)ifindex; |
1da177e4 LT |
100 | } |
101 | ||
102 | static int masq_device_event(struct notifier_block *this, | |
103 | unsigned long event, | |
104 | void *ptr) | |
105 | { | |
a47362a2 | 106 | const struct net_device *dev = ptr; |
b8b8063e | 107 | struct net *net = dev_net(dev); |
e9dc8653 | 108 | |
1da177e4 LT |
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. */ | |
587aa641 | 113 | NF_CT_ASSERT(dev->ifindex != 0); |
1da177e4 | 114 | |
b8b8063e | 115 | nf_ct_iterate_cleanup(net, device_cmp, |
400dad39 | 116 | (void *)(long)dev->ifindex); |
1da177e4 LT |
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 | { | |
6fc68624 DL |
126 | struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev; |
127 | return masq_device_event(this, event, dev); | |
1da177e4 LT |
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 | ||
d3c5ee6d | 138 | static struct xt_target masquerade_tg_reg __read_mostly = { |
1da177e4 | 139 | .name = "MASQUERADE", |
ee999d8b | 140 | .family = NFPROTO_IPV4, |
d3c5ee6d | 141 | .target = masquerade_tg, |
587aa641 | 142 | .targetsize = sizeof(struct nf_nat_multi_range_compat), |
1d5cd909 | 143 | .table = "nat", |
6e23ae2a | 144 | .hooks = 1 << NF_INET_POST_ROUTING, |
d3c5ee6d | 145 | .checkentry = masquerade_tg_check, |
1da177e4 LT |
146 | .me = THIS_MODULE, |
147 | }; | |
148 | ||
d3c5ee6d | 149 | static int __init masquerade_tg_init(void) |
1da177e4 LT |
150 | { |
151 | int ret; | |
152 | ||
d3c5ee6d | 153 | ret = xt_register_target(&masquerade_tg_reg); |
1da177e4 LT |
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 | ||
d3c5ee6d | 165 | static void __exit masquerade_tg_exit(void) |
1da177e4 | 166 | { |
d3c5ee6d | 167 | xt_unregister_target(&masquerade_tg_reg); |
1da177e4 | 168 | unregister_netdevice_notifier(&masq_dev_notifier); |
e905a9ed | 169 | unregister_inetaddr_notifier(&masq_inet_notifier); |
1da177e4 LT |
170 | } |
171 | ||
d3c5ee6d JE |
172 | module_init(masquerade_tg_init); |
173 | module_exit(masquerade_tg_exit); |