[IPV6]: Move nextheader offset to the IP6CB
[linux-2.6] / 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 <net/dsfield.h>
15 #include <net/inet_ecn.h>
16 #include <net/ip.h>
17 #include <net/ipv6.h>
18 #include <net/xfrm.h>
19
20 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
21 {
22         struct ipv6hdr *outer_iph = skb->nh.ipv6h;
23         struct ipv6hdr *inner_iph = skb->h.ipv6h;
24
25         if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
26                 IP6_ECN_set_ce(inner_iph);
27 }
28
29 int xfrm6_rcv_spi(struct sk_buff **pskb, u32 spi)
30 {
31         struct sk_buff *skb = *pskb;
32         int err;
33         u32 seq;
34         struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
35         struct xfrm_state *x;
36         int xfrm_nr = 0;
37         int decaps = 0;
38         int nexthdr;
39         unsigned int nhoff;
40
41         nhoff = IP6CB(skb)->nhoff;
42         nexthdr = skb->nh.raw[nhoff];
43
44         seq = 0;
45         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
46                 goto drop;
47         
48         do {
49                 struct ipv6hdr *iph = skb->nh.ipv6h;
50
51                 if (xfrm_nr == XFRM_MAX_DEPTH)
52                         goto drop;
53
54                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
55                 if (x == NULL)
56                         goto drop;
57                 spin_lock(&x->lock);
58                 if (unlikely(x->km.state != XFRM_STATE_VALID))
59                         goto drop_unlock;
60
61                 if (x->props.replay_window && xfrm_replay_check(x, seq))
62                         goto drop_unlock;
63
64                 if (xfrm_state_check_expire(x))
65                         goto drop_unlock;
66
67                 nexthdr = x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb);
68                 if (nexthdr <= 0)
69                         goto drop_unlock;
70
71                 skb->nh.raw[nhoff] = nexthdr;
72
73                 if (x->props.replay_window)
74                         xfrm_replay_advance(x, seq);
75
76                 x->curlft.bytes += skb->len;
77                 x->curlft.packets++;
78
79                 spin_unlock(&x->lock);
80
81                 xfrm_vec[xfrm_nr++].xvec = x;
82
83                 if (x->props.mode) { /* XXX */
84                         if (nexthdr != IPPROTO_IPV6)
85                                 goto drop;
86                         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
87                                 goto drop;
88                         if (skb_cloned(skb) &&
89                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
90                                 goto drop;
91                         if (x->props.flags & XFRM_STATE_DECAP_DSCP)
92                                 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
93                         if (!(x->props.flags & XFRM_STATE_NOECN))
94                                 ipip6_ecn_decapsulate(skb);
95                         skb->mac.raw = memmove(skb->data - skb->mac_len,
96                                                skb->mac.raw, skb->mac_len);
97                         skb->nh.raw = skb->data;
98                         decaps = 1;
99                         break;
100                 }
101
102                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
103                         goto drop;
104         } while (!err);
105
106         /* Allocate new secpath or COW existing one. */
107         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
108                 struct sec_path *sp;
109                 sp = secpath_dup(skb->sp);
110                 if (!sp)
111                         goto drop;
112                 if (skb->sp)
113                         secpath_put(skb->sp);
114                 skb->sp = sp;
115         }
116
117         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
118                 goto drop;
119
120         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
121         skb->sp->len += xfrm_nr;
122         skb->ip_summed = CHECKSUM_NONE;
123
124         if (decaps) {
125                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
126                         dst_release(skb->dst);
127                         skb->dst = NULL;
128                 }
129                 netif_rx(skb);
130                 return -1;
131         } else {
132                 return 1;
133         }
134
135 drop_unlock:
136         spin_unlock(&x->lock);
137         xfrm_state_put(x);
138 drop:
139         while (--xfrm_nr >= 0)
140                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
141         kfree_skb(skb);
142         return -1;
143 }
144
145 EXPORT_SYMBOL(xfrm6_rcv_spi);
146
147 int xfrm6_rcv(struct sk_buff **pskb)
148 {
149         return xfrm6_rcv_spi(pskb, 0);
150 }