1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* Masquerade. Simple mapping which alters range to a local IP address |
3 | (depending on route). */ |
4 | |
5 | /* (C) 1999-2001 Paul `Rusty' Russell |
6 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> |
7 | */ |
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
9 | #include <linux/module.h> |
10 | #include <linux/netfilter/x_tables.h> |
11 | #include <net/netfilter/nf_nat.h> |
12 | #include <net/netfilter/nf_nat_masquerade.h> |
13 | |
14 | MODULE_LICENSE("GPL" ); |
15 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>" ); |
16 | MODULE_DESCRIPTION("Xtables: automatic-address SNAT" ); |
17 | |
18 | /* FIXME: Multiple targets. --RR */ |
19 | static int masquerade_tg_check(const struct xt_tgchk_param *par) |
20 | { |
21 | const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo; |
22 | |
23 | if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) { |
24 | pr_debug("bad MAP_IPS.\n" ); |
25 | return -EINVAL; |
26 | } |
27 | if (mr->rangesize != 1) { |
28 | pr_debug("bad rangesize %u\n" , mr->rangesize); |
29 | return -EINVAL; |
30 | } |
31 | return nf_ct_netns_get(net: par->net, nfproto: par->family); |
32 | } |
33 | |
34 | static unsigned int |
35 | masquerade_tg(struct sk_buff *skb, const struct xt_action_param *par) |
36 | { |
37 | struct nf_nat_range2 range; |
38 | const struct nf_nat_ipv4_multi_range_compat *mr; |
39 | |
40 | mr = par->targinfo; |
41 | range.flags = mr->range[0].flags; |
42 | range.min_proto = mr->range[0].min; |
43 | range.max_proto = mr->range[0].max; |
44 | |
45 | return nf_nat_masquerade_ipv4(skb, hooknum: xt_hooknum(par), range: &range, |
46 | out: xt_out(par)); |
47 | } |
48 | |
49 | static void masquerade_tg_destroy(const struct xt_tgdtor_param *par) |
50 | { |
51 | nf_ct_netns_put(net: par->net, nfproto: par->family); |
52 | } |
53 | |
54 | #if IS_ENABLED(CONFIG_IPV6) |
55 | static unsigned int |
56 | masquerade_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
57 | { |
58 | return nf_nat_masquerade_ipv6(skb, range: par->targinfo, out: xt_out(par)); |
59 | } |
60 | |
61 | static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par) |
62 | { |
63 | const struct nf_nat_range2 *range = par->targinfo; |
64 | |
65 | if (range->flags & NF_NAT_RANGE_MAP_IPS) |
66 | return -EINVAL; |
67 | |
68 | return nf_ct_netns_get(net: par->net, nfproto: par->family); |
69 | } |
70 | #endif |
71 | |
72 | static struct xt_target masquerade_tg_reg[] __read_mostly = { |
73 | { |
74 | #if IS_ENABLED(CONFIG_IPV6) |
75 | .name = "MASQUERADE" , |
76 | .family = NFPROTO_IPV6, |
77 | .target = masquerade_tg6, |
78 | .targetsize = sizeof(struct nf_nat_range), |
79 | .table = "nat" , |
80 | .hooks = 1 << NF_INET_POST_ROUTING, |
81 | .checkentry = masquerade_tg6_checkentry, |
82 | .destroy = masquerade_tg_destroy, |
83 | .me = THIS_MODULE, |
84 | }, { |
85 | #endif |
86 | .name = "MASQUERADE" , |
87 | .family = NFPROTO_IPV4, |
88 | .target = masquerade_tg, |
89 | .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat), |
90 | .table = "nat" , |
91 | .hooks = 1 << NF_INET_POST_ROUTING, |
92 | .checkentry = masquerade_tg_check, |
93 | .destroy = masquerade_tg_destroy, |
94 | .me = THIS_MODULE, |
95 | } |
96 | }; |
97 | |
98 | static int __init masquerade_tg_init(void) |
99 | { |
100 | int ret; |
101 | |
102 | ret = xt_register_targets(target: masquerade_tg_reg, |
103 | ARRAY_SIZE(masquerade_tg_reg)); |
104 | if (ret) |
105 | return ret; |
106 | |
107 | ret = nf_nat_masquerade_inet_register_notifiers(); |
108 | if (ret) { |
109 | xt_unregister_targets(target: masquerade_tg_reg, |
110 | ARRAY_SIZE(masquerade_tg_reg)); |
111 | return ret; |
112 | } |
113 | |
114 | return ret; |
115 | } |
116 | |
117 | static void __exit masquerade_tg_exit(void) |
118 | { |
119 | xt_unregister_targets(target: masquerade_tg_reg, ARRAY_SIZE(masquerade_tg_reg)); |
120 | nf_nat_masquerade_inet_unregister_notifiers(); |
121 | } |
122 | |
123 | module_init(masquerade_tg_init); |
124 | module_exit(masquerade_tg_exit); |
125 | #if IS_ENABLED(CONFIG_IPV6) |
126 | MODULE_ALIAS("ip6t_MASQUERADE" ); |
127 | #endif |
128 | MODULE_ALIAS("ipt_MASQUERADE" ); |
129 | |