ec7a96e9fa644f63402a10d804e5b8fd383b23c5
[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/dsfield.h>
17 #include <net/inet_ecn.h>
18 #include <net/ip.h>
19 #include <net/ipv6.h>
20 #include <net/xfrm.h>
21
22 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
23 {
24         struct ipv6hdr *outer_iph = skb->nh.ipv6h;
25         struct ipv6hdr *inner_iph = skb->h.ipv6h;
26
27         if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
28                 IP6_ECN_set_ce(inner_iph);
29 }
30
31 int xfrm6_rcv_spi(struct sk_buff *skb, u32 spi)
32 {
33         int err;
34         u32 seq;
35         struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
36         struct xfrm_state *x;
37         int xfrm_nr = 0;
38         int decaps = 0;
39         int nexthdr;
40         unsigned int nhoff;
41
42         nhoff = IP6CB(skb)->nhoff;
43         nexthdr = skb->nh.raw[nhoff];
44
45         seq = 0;
46         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
47                 goto drop;
48         
49         do {
50                 struct ipv6hdr *iph = skb->nh.ipv6h;
51
52                 if (xfrm_nr == XFRM_MAX_DEPTH)
53                         goto drop;
54
55                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
56                 if (x == NULL)
57                         goto drop;
58                 spin_lock(&x->lock);
59                 if (unlikely(x->km.state != XFRM_STATE_VALID))
60                         goto drop_unlock;
61
62                 if (x->props.replay_window && xfrm_replay_check(x, seq))
63                         goto drop_unlock;
64
65                 if (xfrm_state_check_expire(x))
66                         goto drop_unlock;
67
68                 nexthdr = x->type->input(x, skb);
69                 if (nexthdr <= 0)
70                         goto drop_unlock;
71
72                 skb->nh.raw[nhoff] = nexthdr;
73
74                 if (x->props.replay_window)
75                         xfrm_replay_advance(x, seq);
76
77                 x->curlft.bytes += skb->len;
78                 x->curlft.packets++;
79
80                 spin_unlock(&x->lock);
81
82                 xfrm_vec[xfrm_nr++].xvec = x;
83
84                 if (x->props.mode) { /* XXX */
85                         if (nexthdr != IPPROTO_IPV6)
86                                 goto drop;
87                         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
88                                 goto drop;
89                         if (skb_cloned(skb) &&
90                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
91                                 goto drop;
92                         if (x->props.flags & XFRM_STATE_DECAP_DSCP)
93                                 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
94                         if (!(x->props.flags & XFRM_STATE_NOECN))
95                                 ipip6_ecn_decapsulate(skb);
96                         skb->mac.raw = memmove(skb->data - skb->mac_len,
97                                                skb->mac.raw, skb->mac_len);
98                         skb->nh.raw = skb->data;
99                         decaps = 1;
100                         break;
101                 }
102
103                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
104                         goto drop;
105         } while (!err);
106
107         /* Allocate new secpath or COW existing one. */
108         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
109                 struct sec_path *sp;
110                 sp = secpath_dup(skb->sp);
111                 if (!sp)
112                         goto drop;
113                 if (skb->sp)
114                         secpath_put(skb->sp);
115                 skb->sp = sp;
116         }
117
118         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
119                 goto drop;
120
121         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
122         skb->sp->len += xfrm_nr;
123         skb->ip_summed = CHECKSUM_NONE;
124
125         nf_reset(skb);
126
127         if (decaps) {
128                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
129                         dst_release(skb->dst);
130                         skb->dst = NULL;
131                 }
132                 netif_rx(skb);
133                 return -1;
134         } else {
135 #ifdef CONFIG_NETFILTER
136                 skb->nh.ipv6h->payload_len = htons(skb->len);
137                 __skb_push(skb, skb->data - skb->nh.raw);
138
139                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
140                         ip6_rcv_finish);
141                 return -1;
142 #else
143                 return 1;
144 #endif
145         }
146
147 drop_unlock:
148         spin_unlock(&x->lock);
149         xfrm_state_put(x);
150 drop:
151         while (--xfrm_nr >= 0)
152                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
153         kfree_skb(skb);
154         return -1;
155 }
156
157 EXPORT_SYMBOL(xfrm6_rcv_spi);
158
159 int xfrm6_rcv(struct sk_buff **pskb)
160 {
161         return xfrm6_rcv_spi(*pskb, 0);
162 }