97b75f9bfbcd6852bdff9ca2d2e218b3539a0f8b
[karo-tx-linux.git] / net / netfilter / nf_nat_redirect.c
1 /*
2  * (C) 1999-2001 Paul `Rusty' Russell
3  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
4  * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
11  * NAT funded by Astaro.
12  */
13
14 #include <linux/if.h>
15 #include <linux/inetdevice.h>
16 #include <linux/ip.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/netdevice.h>
20 #include <linux/netfilter.h>
21 #include <linux/types.h>
22 #include <linux/netfilter_ipv4.h>
23 #include <linux/netfilter_ipv6.h>
24 #include <linux/netfilter/x_tables.h>
25 #include <net/addrconf.h>
26 #include <net/checksum.h>
27 #include <net/protocol.h>
28 #include <net/netfilter/nf_nat.h>
29 #include <net/netfilter/nf_nat_redirect.h>
30
31 unsigned int
32 nf_nat_redirect_ipv4(struct sk_buff *skb,
33                      const struct nf_nat_ipv4_multi_range_compat *mr,
34                      unsigned int hooknum)
35 {
36         struct nf_conn *ct;
37         enum ip_conntrack_info ctinfo;
38         __be32 newdst;
39         struct nf_nat_range newrange;
40
41         NF_CT_ASSERT(hooknum == NF_INET_PRE_ROUTING ||
42                      hooknum == NF_INET_LOCAL_OUT);
43
44         ct = nf_ct_get(skb, &ctinfo);
45         NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
46
47         /* Local packets: make them go to loopback */
48         if (hooknum == NF_INET_LOCAL_OUT) {
49                 newdst = htonl(0x7F000001);
50         } else {
51                 struct in_device *indev;
52                 struct in_ifaddr *ifa;
53
54                 newdst = 0;
55
56                 rcu_read_lock();
57                 indev = __in_dev_get_rcu(skb->dev);
58                 if (indev != NULL) {
59                         ifa = indev->ifa_list;
60                         newdst = ifa->ifa_local;
61                 }
62                 rcu_read_unlock();
63
64                 if (!newdst)
65                         return NF_DROP;
66         }
67
68         /* Transfer from original range. */
69         memset(&newrange.min_addr, 0, sizeof(newrange.min_addr));
70         memset(&newrange.max_addr, 0, sizeof(newrange.max_addr));
71         newrange.flags       = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS;
72         newrange.min_addr.ip = newdst;
73         newrange.max_addr.ip = newdst;
74         newrange.min_proto   = mr->range[0].min;
75         newrange.max_proto   = mr->range[0].max;
76
77         /* Hand modified range to generic setup. */
78         return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
79 }
80 EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv4);
81
82 static const struct in6_addr loopback_addr = IN6ADDR_LOOPBACK_INIT;
83
84 unsigned int
85 nf_nat_redirect_ipv6(struct sk_buff *skb, const struct nf_nat_range *range,
86                      unsigned int hooknum)
87 {
88         struct nf_nat_range newrange;
89         struct in6_addr newdst;
90         enum ip_conntrack_info ctinfo;
91         struct nf_conn *ct;
92
93         ct = nf_ct_get(skb, &ctinfo);
94         if (hooknum == NF_INET_LOCAL_OUT) {
95                 newdst = loopback_addr;
96         } else {
97                 struct inet6_dev *idev;
98                 struct inet6_ifaddr *ifa;
99                 bool addr = false;
100
101                 rcu_read_lock();
102                 idev = __in6_dev_get(skb->dev);
103                 if (idev != NULL) {
104                         list_for_each_entry(ifa, &idev->addr_list, if_list) {
105                                 newdst = ifa->addr;
106                                 addr = true;
107                                 break;
108                         }
109                 }
110                 rcu_read_unlock();
111
112                 if (!addr)
113                         return NF_DROP;
114         }
115
116         newrange.flags          = range->flags | NF_NAT_RANGE_MAP_IPS;
117         newrange.min_addr.in6   = newdst;
118         newrange.max_addr.in6   = newdst;
119         newrange.min_proto      = range->min_proto;
120         newrange.max_proto      = range->max_proto;
121
122         return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_DST);
123 }
124 EXPORT_SYMBOL_GPL(nf_nat_redirect_ipv6);
125
126 MODULE_LICENSE("GPL");
127 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");