Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux...
[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 #include <net/netfilter/nf_queue.h>
12
13 int ip6_route_me_harder(struct sk_buff *skb)
14 {
15         struct ipv6hdr *iph = ipv6_hdr(skb);
16         struct dst_entry *dst;
17         struct flowi fl = {
18                 .oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
19                 .mark = skb->mark,
20                 .nl_u =
21                 { .ip6_u =
22                   { .daddr = iph->daddr,
23                     .saddr = iph->saddr, } },
24         };
25
26         dst = ip6_route_output(&init_net, skb->sk, &fl);
27
28 #ifdef CONFIG_XFRM
29         if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
30             xfrm_decode_session(skb, &fl, AF_INET6) == 0)
31                 if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0))
32                         return -1;
33 #endif
34
35         if (dst->error) {
36                 IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
37                 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
38                 dst_release(dst);
39                 return -EINVAL;
40         }
41
42         /* Drop old route. */
43         dst_release(skb->dst);
44
45         skb->dst = dst;
46         return 0;
47 }
48 EXPORT_SYMBOL(ip6_route_me_harder);
49
50 /*
51  * Extra routing may needed on local out, as the QUEUE target never
52  * returns control to the table.
53  */
54
55 struct ip6_rt_info {
56         struct in6_addr daddr;
57         struct in6_addr saddr;
58 };
59
60 static void nf_ip6_saveroute(const struct sk_buff *skb,
61                              struct nf_queue_entry *entry)
62 {
63         struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
64
65         if (entry->hook == NF_INET_LOCAL_OUT) {
66                 struct ipv6hdr *iph = ipv6_hdr(skb);
67
68                 rt_info->daddr = iph->daddr;
69                 rt_info->saddr = iph->saddr;
70         }
71 }
72
73 static int nf_ip6_reroute(struct sk_buff *skb,
74                           const struct nf_queue_entry *entry)
75 {
76         struct ip6_rt_info *rt_info = nf_queue_entry_reroute(entry);
77
78         if (entry->hook == NF_INET_LOCAL_OUT) {
79                 struct ipv6hdr *iph = ipv6_hdr(skb);
80                 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
81                     !ipv6_addr_equal(&iph->saddr, &rt_info->saddr))
82                         return ip6_route_me_harder(skb);
83         }
84         return 0;
85 }
86
87 static int nf_ip6_route(struct dst_entry **dst, struct flowi *fl)
88 {
89         *dst = ip6_route_output(&init_net, NULL, fl);
90         return (*dst)->error;
91 }
92
93 __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook,
94                              unsigned int dataoff, u_int8_t protocol)
95 {
96         struct ipv6hdr *ip6h = ipv6_hdr(skb);
97         __sum16 csum = 0;
98
99         switch (skb->ip_summed) {
100         case CHECKSUM_COMPLETE:
101                 if (hook != NF_INET_PRE_ROUTING && hook != NF_INET_LOCAL_IN)
102                         break;
103                 if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
104                                      skb->len - dataoff, protocol,
105                                      csum_sub(skb->csum,
106                                               skb_checksum(skb, 0,
107                                                            dataoff, 0)))) {
108                         skb->ip_summed = CHECKSUM_UNNECESSARY;
109                         break;
110                 }
111                 /* fall through */
112         case CHECKSUM_NONE:
113                 skb->csum = ~csum_unfold(
114                                 csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
115                                              skb->len - dataoff,
116                                              protocol,
117                                              csum_sub(0,
118                                                       skb_checksum(skb, 0,
119                                                                    dataoff, 0))));
120                 csum = __skb_checksum_complete(skb);
121         }
122         return csum;
123 }
124 EXPORT_SYMBOL(nf_ip6_checksum);
125
126 static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook,
127                                        unsigned int dataoff, unsigned int len,
128                                        u_int8_t protocol)
129 {
130         struct ipv6hdr *ip6h = ipv6_hdr(skb);
131         __wsum hsum;
132         __sum16 csum = 0;
133
134         switch (skb->ip_summed) {
135         case CHECKSUM_COMPLETE:
136                 if (len == skb->len - dataoff)
137                         return nf_ip6_checksum(skb, hook, dataoff, protocol);
138                 /* fall through */
139         case CHECKSUM_NONE:
140                 hsum = skb_checksum(skb, 0, dataoff, 0);
141                 skb->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
142                                                          &ip6h->daddr,
143                                                          skb->len - dataoff,
144                                                          protocol,
145                                                          csum_sub(0, hsum)));
146                 skb->ip_summed = CHECKSUM_NONE;
147                 csum = __skb_checksum_complete_head(skb, dataoff + len);
148                 if (!csum)
149                         skb->ip_summed = CHECKSUM_UNNECESSARY;
150         }
151         return csum;
152 };
153
154 static const struct nf_afinfo nf_ip6_afinfo = {
155         .family                 = AF_INET6,
156         .checksum               = nf_ip6_checksum,
157         .checksum_partial       = nf_ip6_checksum_partial,
158         .route                  = nf_ip6_route,
159         .saveroute              = nf_ip6_saveroute,
160         .reroute                = nf_ip6_reroute,
161         .route_key_size         = sizeof(struct ip6_rt_info),
162 };
163
164 int __init ipv6_netfilter_init(void)
165 {
166         return nf_register_afinfo(&nf_ip6_afinfo);
167 }
168
169 /* This can be called from inet6_init() on errors, so it cannot
170  * be marked __exit. -DaveM
171  */
172 void ipv6_netfilter_fini(void)
173 {
174         nf_unregister_afinfo(&nf_ip6_afinfo);
175 }