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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 (par->hooknum == NF_INET_PRE_ROUTING ||
37 par->hooknum == 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(par->hooknum));
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 0;
64}
65
66static unsigned int
67netmap_tg4(struct sk_buff *skb, const struct xt_action_param *par)
68{
69 struct nf_conn *ct;
70 enum ip_conntrack_info ctinfo;
71 __be32 new_ip, netmask;
72 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
73 struct nf_nat_range newrange;
74
75 NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING ||
76 par->hooknum == NF_INET_POST_ROUTING ||
77 par->hooknum == NF_INET_LOCAL_OUT ||
78 par->hooknum == NF_INET_LOCAL_IN);
79 ct = nf_ct_get(skb, &ctinfo);
80
81 netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip);
82
83 if (par->hooknum == NF_INET_PRE_ROUTING ||
84 par->hooknum == NF_INET_LOCAL_OUT)
85 new_ip = ip_hdr(skb)->daddr & ~netmask;
86 else
87 new_ip = ip_hdr(skb)->saddr & ~netmask;
88 new_ip |= mr->range[0].min_ip & netmask;
89
90 memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
91 memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
92 newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
93 newrange.min_addr.ip = new_ip;
94 newrange.max_addr.ip = new_ip;
95 newrange.min_proto = mr->range[0].min;
96 newrange.max_proto = mr->range[0].max;
97
98
99 return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(par->hooknum));
100}
101
102static int netmap_tg4_check(const struct xt_tgchk_param *par)
103{
104 const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
105
106 if (!(mr->range[0].flags & NF_NAT_RANGE_MAP_IPS)) {
107 pr_debug("bad MAP_IPS.\n");
108 return -EINVAL;
109 }
110 if (mr->rangesize != 1) {
111 pr_debug("bad rangesize %u.\n", mr->rangesize);
112 return -EINVAL;
113 }
114 return 0;
115}
116
117static struct xt_target netmap_tg_reg[] __read_mostly = {
118 {
119 .name = "NETMAP",
120 .family = NFPROTO_IPV6,
121 .revision = 0,
122 .target = netmap_tg6,
123 .targetsize = sizeof(struct nf_nat_range),
124 .table = "nat",
125 .hooks = (1 << NF_INET_PRE_ROUTING) |
126 (1 << NF_INET_POST_ROUTING) |
127 (1 << NF_INET_LOCAL_OUT) |
128 (1 << NF_INET_LOCAL_IN),
129 .checkentry = netmap_tg6_checkentry,
130 .me = THIS_MODULE,
131 },
132 {
133 .name = "NETMAP",
134 .family = NFPROTO_IPV4,
135 .revision = 0,
136 .target = netmap_tg4,
137 .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
138 .table = "nat",
139 .hooks = (1 << NF_INET_PRE_ROUTING) |
140 (1 << NF_INET_POST_ROUTING) |
141 (1 << NF_INET_LOCAL_OUT) |
142 (1 << NF_INET_LOCAL_IN),
143 .checkentry = netmap_tg4_check,
144 .me = THIS_MODULE,
145 },
146};
147
148static int __init netmap_tg_init(void)
149{
150 return xt_register_targets(netmap_tg_reg, ARRAY_SIZE(netmap_tg_reg));
151}
152
153static void netmap_tg_exit(void)
154{
155 xt_unregister_targets(netmap_tg_reg, ARRAY_SIZE(netmap_tg_reg));
156}
157
158module_init(netmap_tg_init);
159module_exit(netmap_tg_exit);
160
161MODULE_LICENSE("GPL");
162MODULE_DESCRIPTION("Xtables: 1:1 NAT mapping of subnets");
163MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
164MODULE_ALIAS("ip6t_NETMAP");
165MODULE_ALIAS("ipt_NETMAP");
166
