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10#include <linux/ip.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/netdevice.h>
14#include <linux/ipv6.h>
15#include <linux/netfilter.h>
16#include <linux/netfilter_ipv4.h>
17#include <linux/netfilter_ipv6.h>
18#include <linux/netfilter/x_tables.h>
19#include <net/netfilter/nf_nat.h>
20
21static unsigned int
22netmap_tg6(struct sk_buff *skb, const struct xt_action_param *par)
23{
24 const struct nf_nat_range *range = par->targinfo;
25 struct nf_nat_range newrange;
26 struct nf_conn *ct;
27 enum ip_conntrack_info ctinfo;
28 union nf_inet_addr new_addr, netmask;
29 unsigned int i;
30
31 ct = nf_ct_get(skb, &ctinfo);
32 for (i = 0; i < ARRAY_SIZE(range->min_addr.ip6); i++)
33 netmask.ip6[i] = ~(range->min_addr.ip6[i] ^
34 range->max_addr.ip6[i]);
35
36 if (xt_hooknum(par) == NF_INET_PRE_ROUTING ||
37 xt_hooknum(par) == NF_INET_LOCAL_OUT)
38 new_addr.in6 = ipv6_hdr(skb)->daddr;
39 else
40 new_addr.in6 = ipv6_hdr(skb)->saddr;
41
42 for (i = 0; i < ARRAY_SIZE(new_addr.ip6); i++) {
43 new_addr.ip6[i] &= ~netmask.ip6[i];
44 new_addr.ip6[i] |= range->min_addr.ip6[i] &
45 netmask.ip6[i];
46 }
47
48 newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS;
49 newrange.min_addr = new_addr;
50 newrange.max_addr = new_addr;
51 newrange.min_proto = range->min_proto;
52 newrange.max_proto = range->max_proto;
53
54 return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(xt_hooknum(par)));
55}
56
57static int netmap_tg6_checkentry(const struct xt_tgchk_param *par)
58{
59 const struct nf_nat_range *range = par->targinfo;
60
61 if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
62 return -EINVAL;
63 return nf_ct_netns_get(par->net, par->family);
64}
65
66static void netmap_tg_destroy(const struct xt_tgdtor_param *par)
67{
68 nf_ct_netns_put(par->net, par->family);
69}
70
71static unsigned int
72netmap_tg4(struct sk_buff *skb, const struct xt_action_param *par)
73{
74 struct nf_conn *ct;
75 enum ip_conntrack_info ctinfo;
76 __be32 new_ip, netmask;
77 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
78 struct nf_nat_range newrange;
79
80 WARN_ON(xt_hooknum(par) != NF_INET_PRE_ROUTING &&
81 xt_hooknum(par) != NF_INET_POST_ROUTING &&
82 xt_hooknum(par) != NF_INET_LOCAL_OUT &&
83 xt_hooknum(par) != NF_INET_LOCAL_IN);
84 ct = nf_ct_get(skb, &ctinfo);
85
86 netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);
87
88 if (xt_hooknum(par) == NF_INET_PRE_ROUTING ||
89 xt_hooknum(par) == NF_INET_LOCAL_OUT)
90 new_ip = ip_hdr(skb)->daddr & ~netmask;
91 else
92 new_ip = ip_hdr(skb)->saddr & ~netmask;
93 new_ip |= mr->range[0].min_ip & netmask;
94
95 memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
96 memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
97 newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
98 newrange.min_addr.ip = new_ip;
99 newrange.max_addr.ip = new_ip;
100 newrange.min_proto = mr->range[0].min;
101 newrange.max_proto = mr->range[0].max;
102
103
104 return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(xt_hooknum(par)));
105}
106
107static int netmap_tg4_check(const struct xt_tgchk_param *par)
108{
109 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
110
111 if (!(mr->range[0].flags & NF_NAT_RANGE_MAP_IPS)) {
112 pr_debug("bad MAP_IPS.\n");
113 return -EINVAL;
114 }
115 if (mr->rangesize != 1) {
116 pr_debug("bad rangesize %u.\n", mr->rangesize);
117 return -EINVAL;
118 }
119 return nf_ct_netns_get(par->net, par->family);
120}
121
122static struct xt_target netmap_tg_reg[] __read_mostly = {
123 {
124 .name = "NETMAP",
125 .family = NFPROTO_IPV6,
126 .revision = 0,
127 .target = netmap_tg6,
128 .targetsize = sizeof(struct nf_nat_range),
129 .table = "nat",
130 .hooks = (1 << NF_INET_PRE_ROUTING) |
131 (1 << NF_INET_POST_ROUTING) |
132 (1 << NF_INET_LOCAL_OUT) |
133 (1 << NF_INET_LOCAL_IN),
134 .checkentry = netmap_tg6_checkentry,
135 .destroy = netmap_tg_destroy,
136 .me = THIS_MODULE,
137 },
138 {
139 .name = "NETMAP",
140 .family = NFPROTO_IPV4,
141 .revision = 0,
142 .target = netmap_tg4,
143 .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
144 .table = "nat",
145 .hooks = (1 << NF_INET_PRE_ROUTING) |
146 (1 << NF_INET_POST_ROUTING) |
147 (1 << NF_INET_LOCAL_OUT) |
148 (1 << NF_INET_LOCAL_IN),
149 .checkentry = netmap_tg4_check,
150 .destroy = netmap_tg_destroy,
151 .me = THIS_MODULE,
152 },
153};
154
155static int __init netmap_tg_init(void)
156{
157 return xt_register_targets(netmap_tg_reg, ARRAY_SIZE(netmap_tg_reg));
158}
159
160static void netmap_tg_exit(void)
161{
162 xt_unregister_targets(netmap_tg_reg, ARRAY_SIZE(netmap_tg_reg));
163}
164
165module_init(netmap_tg_init);
166module_exit(netmap_tg_exit);
167
168MODULE_LICENSE("GPL");
169MODULE_DESCRIPTION("Xtables: 1:1 NAT mapping of subnets");
170MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
171MODULE_ALIAS("ip6t_NETMAP");
172MODULE_ALIAS("ipt_NETMAP");
173
