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11#include <linux/module.h>
12#include <linux/skbuff.h>
13#include <linux/netfilter.h>
14#include <linux/netfilter/x_tables.h>
15#include <net/netfilter/nf_nat_core.h>
16
17static int xt_nat_checkentry_v0(const struct xt_tgchk_param *par)
18{
19 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
20
21 if (mr->rangesize != 1) {
22 pr_info("%s: multiple ranges no longer supported\n",
23 par->target->name);
24 return -EINVAL;
25 }
26 return 0;
27}
28
29static void xt_nat_convert_range(struct nf_nat_range *dst,
30 const struct nf_nat_ipv4_range *src)
31{
32 memset(&dst->min_addr, 0, sizeof(dst->min_addr));
33 memset(&dst->max_addr, 0, sizeof(dst->max_addr));
34
35 dst->flags = src->flags;
36 dst->min_addr.ip = src->min_ip;
37 dst->max_addr.ip = src->max_ip;
38 dst->min_proto = src->min;
39 dst->max_proto = src->max;
40}
41
42static unsigned int
43xt_snat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
44{
45 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
46 struct nf_nat_range range;
47 enum ip_conntrack_info ctinfo;
48 struct nf_conn *ct;
49
50 ct = nf_ct_get(skb, &ctinfo);
51 NF_CT_ASSERT(ct != NULL &&
52 (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
53 ctinfo == IP_CT_RELATED_REPLY));
54
55 xt_nat_convert_range(&range, &mr->range[0]);
56 return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
57}
58
59static unsigned int
60xt_dnat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
61{
62 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
63 struct nf_nat_range range;
64 enum ip_conntrack_info ctinfo;
65 struct nf_conn *ct;
66
67 ct = nf_ct_get(skb, &ctinfo);
68 NF_CT_ASSERT(ct != NULL &&
69 (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
70
71 xt_nat_convert_range(&range, &mr->range[0]);
72 return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
73}
74
75static unsigned int
76xt_snat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
77{
78 const struct nf_nat_range *range = par->targinfo;
79 enum ip_conntrack_info ctinfo;
80 struct nf_conn *ct;
81
82 ct = nf_ct_get(skb, &ctinfo);
83 NF_CT_ASSERT(ct != NULL &&
84 (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
85 ctinfo == IP_CT_RELATED_REPLY));
86
87 return nf_nat_setup_info(ct, range, NF_NAT_MANIP_SRC);
88}
89
90static unsigned int
91xt_dnat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
92{
93 const struct nf_nat_range *range = par->targinfo;
94 enum ip_conntrack_info ctinfo;
95 struct nf_conn *ct;
96
97 ct = nf_ct_get(skb, &ctinfo);
98 NF_CT_ASSERT(ct != NULL &&
99 (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
100
101 return nf_nat_setup_info(ct, range, NF_NAT_MANIP_DST);
102}
103
104static struct xt_target xt_nat_target_reg[] __read_mostly = {
105 {
106 .name = "SNAT",
107 .revision = 0,
108 .checkentry = xt_nat_checkentry_v0,
109 .target = xt_snat_target_v0,
110 .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
111 .family = NFPROTO_IPV4,
112 .table = "nat",
113 .hooks = (1 << NF_INET_POST_ROUTING) |
114 (1 << NF_INET_LOCAL_IN),
115 .me = THIS_MODULE,
116 },
117 {
118 .name = "DNAT",
119 .revision = 0,
120 .checkentry = xt_nat_checkentry_v0,
121 .target = xt_dnat_target_v0,
122 .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
123 .family = NFPROTO_IPV4,
124 .table = "nat",
125 .hooks = (1 << NF_INET_PRE_ROUTING) |
126 (1 << NF_INET_LOCAL_OUT),
127 .me = THIS_MODULE,
128 },
129 {
130 .name = "SNAT",
131 .revision = 1,
132 .target = xt_snat_target_v1,
133 .targetsize = sizeof(struct nf_nat_range),
134 .table = "nat",
135 .hooks = (1 << NF_INET_POST_ROUTING) |
136 (1 << NF_INET_LOCAL_IN),
137 .me = THIS_MODULE,
138 },
139 {
140 .name = "DNAT",
141 .revision = 1,
142 .target = xt_dnat_target_v1,
143 .targetsize = sizeof(struct nf_nat_range),
144 .table = "nat",
145 .hooks = (1 << NF_INET_PRE_ROUTING) |
146 (1 << NF_INET_LOCAL_OUT),
147 .me = THIS_MODULE,
148 },
149};
150
151static int __init xt_nat_init(void)
152{
153 return xt_register_targets(xt_nat_target_reg,
154 ARRAY_SIZE(xt_nat_target_reg));
155}
156
157static void __exit xt_nat_exit(void)
158{
159 xt_unregister_targets(xt_nat_target_reg, ARRAY_SIZE(xt_nat_target_reg));
160}
161
162module_init(xt_nat_init);
163module_exit(xt_nat_exit);
164
165MODULE_LICENSE("GPL");
166MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
167MODULE_ALIAS("ipt_SNAT");
168MODULE_ALIAS("ipt_DNAT");
169MODULE_ALIAS("ip6t_SNAT");
170MODULE_ALIAS("ip6t_DNAT");
171
