[XFRM]: Add XFRM_MODE_xxx for future use.
[linux-2.6.git] / net / ipv6 / xfrm6_input.c
1 /*
2  * xfrm6_input.c: based on net/ipv4/xfrm4_input.c
3  *
4  * Authors:
5  *      Mitsuru KANDA @USAGI
6  *      Kazunori MIYAZAWA @USAGI
7  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
8  *      YOSHIFUJI Hideaki @USAGI
9  *              IPv6 support
10  */
11
12 #include <linux/module.h>
13 #include <linux/string.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_ipv6.h>
16 #include <net/ipv6.h>
17 #include <net/xfrm.h>
18
19 int xfrm6_rcv_spi(struct sk_buff *skb, u32 spi)
20 {
21         int err;
22         u32 seq;
23         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
24         struct xfrm_state *x;
25         int xfrm_nr = 0;
26         int decaps = 0;
27         int nexthdr;
28         unsigned int nhoff;
29
30         nhoff = IP6CB(skb)->nhoff;
31         nexthdr = skb->nh.raw[nhoff];
32
33         seq = 0;
34         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
35                 goto drop;
36         
37         do {
38                 struct ipv6hdr *iph = skb->nh.ipv6h;
39
40                 if (xfrm_nr == XFRM_MAX_DEPTH)
41                         goto drop;
42
43                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
44                 if (x == NULL)
45                         goto drop;
46                 spin_lock(&x->lock);
47                 if (unlikely(x->km.state != XFRM_STATE_VALID))
48                         goto drop_unlock;
49
50                 if (x->props.replay_window && xfrm_replay_check(x, seq))
51                         goto drop_unlock;
52
53                 if (xfrm_state_check_expire(x))
54                         goto drop_unlock;
55
56                 nexthdr = x->type->input(x, skb);
57                 if (nexthdr <= 0)
58                         goto drop_unlock;
59
60                 skb->nh.raw[nhoff] = nexthdr;
61
62                 if (x->props.replay_window)
63                         xfrm_replay_advance(x, seq);
64
65                 x->curlft.bytes += skb->len;
66                 x->curlft.packets++;
67
68                 spin_unlock(&x->lock);
69
70                 xfrm_vec[xfrm_nr++] = x;
71
72                 if (x->mode->input(x, skb))
73                         goto drop;
74
75                 if (x->props.mode == XFRM_MODE_TUNNEL) { /* XXX */
76                         decaps = 1;
77                         break;
78                 }
79
80                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
81                         goto drop;
82         } while (!err);
83
84         /* Allocate new secpath or COW existing one. */
85         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
86                 struct sec_path *sp;
87                 sp = secpath_dup(skb->sp);
88                 if (!sp)
89                         goto drop;
90                 if (skb->sp)
91                         secpath_put(skb->sp);
92                 skb->sp = sp;
93         }
94
95         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
96                 goto drop;
97
98         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
99                xfrm_nr * sizeof(xfrm_vec[0]));
100         skb->sp->len += xfrm_nr;
101         skb->ip_summed = CHECKSUM_NONE;
102
103         nf_reset(skb);
104
105         if (decaps) {
106                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
107                         dst_release(skb->dst);
108                         skb->dst = NULL;
109                 }
110                 netif_rx(skb);
111                 return -1;
112         } else {
113 #ifdef CONFIG_NETFILTER
114                 skb->nh.ipv6h->payload_len = htons(skb->len);
115                 __skb_push(skb, skb->data - skb->nh.raw);
116
117                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
118                         ip6_rcv_finish);
119                 return -1;
120 #else
121                 return 1;
122 #endif
123         }
124
125 drop_unlock:
126         spin_unlock(&x->lock);
127         xfrm_state_put(x);
128 drop:
129         while (--xfrm_nr >= 0)
130                 xfrm_state_put(xfrm_vec[xfrm_nr]);
131         kfree_skb(skb);
132         return -1;
133 }
134
135 EXPORT_SYMBOL(xfrm6_rcv_spi);
136
137 int xfrm6_rcv(struct sk_buff **pskb)
138 {
139         return xfrm6_rcv_spi(*pskb, 0);
140 }