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[linux-2.6] / net / ipv6 / netfilter.c
1 #include <linux/kernel.h>
2 #include <linux/init.h>
3 #include <linux/ipv6.h>
4 #include <linux/netfilter.h>
5 #include <linux/netfilter_ipv6.h>
6 #include <net/dst.h>
7 #include <net/ipv6.h>
8 #include <net/ip6_route.h>
9 #include <net/xfrm.h>
10 #include <net/ip6_checksum.h>
11
12 int ip6_route_me_harder(struct sk_buff *skb)
13 {
14         struct ipv6hdr *iph = skb->nh.ipv6h;
15         struct dst_entry *dst;
16         struct flowi fl = {
17                 .oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
18                 .nl_u =
19                 { .ip6_u =
20                   { .daddr = iph->daddr,
21                     .saddr = iph->saddr, } },
22         };
23
24         dst = ip6_route_output(skb->sk, &fl);
25
26 #ifdef CONFIG_XFRM
27         if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
28             xfrm_decode_session(skb, &fl, AF_INET6) == 0)
29                 if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0))
30                         return -1;
31 #endif
32
33         if (dst->error) {
34                 IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
35                 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
36                 dst_release(dst);
37                 return -EINVAL;
38         }
39
40         /* Drop old route. */
41         dst_release(skb->dst);
42
43         skb->dst = dst;
44         return 0;
45 }
46 EXPORT_SYMBOL(ip6_route_me_harder);
47
48 /*
49  * Extra routing may needed on local out, as the QUEUE target never
50  * returns control to the table.
51  */
52
53 struct ip6_rt_info {
54         struct in6_addr daddr;
55         struct in6_addr saddr;
56 };
57
58 static void nf_ip6_saveroute(const struct sk_buff *skb, struct nf_info *info)
59 {
60         struct ip6_rt_info *rt_info = nf_info_reroute(info);
61
62         if (info->hook == NF_IP6_LOCAL_OUT) {
63                 struct ipv6hdr *iph = skb->nh.ipv6h;
64
65                 rt_info->daddr = iph->daddr;
66                 rt_info->saddr = iph->saddr;
67         }
68 }
69
70 static int nf_ip6_reroute(struct sk_buff **pskb, const struct nf_info *info)
71 {
72         struct ip6_rt_info *rt_info = nf_info_reroute(info);
73
74         if (info->hook == NF_IP6_LOCAL_OUT) {
75                 struct ipv6hdr *iph = (*pskb)->nh.ipv6h;
76                 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
77                     !ipv6_addr_equal(&iph->saddr, &rt_info->saddr))
78                         return ip6_route_me_harder(*pskb);
79         }
80         return 0;
81 }
82
83 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
84                              unsigned int dataoff, u_int8_t protocol)
85 {
86         struct ipv6hdr *ip6h = skb->nh.ipv6h;
87         __sum16 csum = 0;
88
89         switch (skb->ip_summed) {
90         case CHECKSUM_COMPLETE:
91                 if (hook != NF_IP6_PRE_ROUTING && hook != NF_IP6_LOCAL_IN)
92                         break;
93                 if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
94                                      skb->len - dataoff, protocol,
95                                      csum_sub(skb->csum,
96                                               skb_checksum(skb, 0,
97                                                            dataoff, 0)))) {
98                         skb->ip_summed = CHECKSUM_UNNECESSARY;
99                         break;
100                 }
101                 /* fall through */
102         case CHECKSUM_NONE:
103                 skb->csum = ~csum_unfold(
104                                 csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
105                                              skb->len - dataoff,
106                                              protocol,
107                                              csum_sub(0,
108                                                       skb_checksum(skb, 0,
109                                                                    dataoff, 0))));
110                 csum = __skb_checksum_complete(skb);
111         }
112         return csum;
113 }
114
115 EXPORT_SYMBOL(nf_ip6_checksum);
116
117 static struct nf_afinfo nf_ip6_afinfo = {
118         .family         = AF_INET6,
119         .checksum       = nf_ip6_checksum,
120         .saveroute      = nf_ip6_saveroute,
121         .reroute        = nf_ip6_reroute,
122         .route_key_size = sizeof(struct ip6_rt_info),
123 };
124
125 int __init ipv6_netfilter_init(void)
126 {
127         return nf_register_afinfo(&nf_ip6_afinfo);
128 }
129
130 /* This can be called from inet6_init() on errors, so it cannot
131  * be marked __exit. -DaveM
132  */
133 void ipv6_netfilter_fini(void)
134 {
135         nf_unregister_afinfo(&nf_ip6_afinfo);
136 }