[NETFILTER]: nf_conntrack: attach conntrack to locally generated ICMPv6 error
[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 **pskb, u32 spi)
32 {
33         struct sk_buff *skb = *pskb;
34         int err;
35         u32 seq;
36         struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
37         struct xfrm_state *x;
38         int xfrm_nr = 0;
39         int decaps = 0;
40         int nexthdr;
41         unsigned int nhoff;
42
43         nhoff = IP6CB(skb)->nhoff;
44         nexthdr = skb->nh.raw[nhoff];
45
46         seq = 0;
47         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
48                 goto drop;
49         
50         do {
51                 struct ipv6hdr *iph = skb->nh.ipv6h;
52
53                 if (xfrm_nr == XFRM_MAX_DEPTH)
54                         goto drop;
55
56                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, nexthdr, AF_INET6);
57                 if (x == NULL)
58                         goto drop;
59                 spin_lock(&x->lock);
60                 if (unlikely(x->km.state != XFRM_STATE_VALID))
61                         goto drop_unlock;
62
63                 if (x->props.replay_window && xfrm_replay_check(x, seq))
64                         goto drop_unlock;
65
66                 if (xfrm_state_check_expire(x))
67                         goto drop_unlock;
68
69                 nexthdr = x->type->input(x, &(xfrm_vec[xfrm_nr].decap), skb);
70                 if (nexthdr <= 0)
71                         goto drop_unlock;
72
73                 skb->nh.raw[nhoff] = nexthdr;
74
75                 if (x->props.replay_window)
76                         xfrm_replay_advance(x, seq);
77
78                 x->curlft.bytes += skb->len;
79                 x->curlft.packets++;
80
81                 spin_unlock(&x->lock);
82
83                 xfrm_vec[xfrm_nr++].xvec = x;
84
85                 if (x->props.mode) { /* XXX */
86                         if (nexthdr != IPPROTO_IPV6)
87                                 goto drop;
88                         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
89                                 goto drop;
90                         if (skb_cloned(skb) &&
91                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
92                                 goto drop;
93                         if (x->props.flags & XFRM_STATE_DECAP_DSCP)
94                                 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
95                         if (!(x->props.flags & XFRM_STATE_NOECN))
96                                 ipip6_ecn_decapsulate(skb);
97                         skb->mac.raw = memmove(skb->data - skb->mac_len,
98                                                skb->mac.raw, skb->mac_len);
99                         skb->nh.raw = skb->data;
100                         decaps = 1;
101                         break;
102                 }
103
104                 if ((err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) < 0)
105                         goto drop;
106         } while (!err);
107
108         /* Allocate new secpath or COW existing one. */
109         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
110                 struct sec_path *sp;
111                 sp = secpath_dup(skb->sp);
112                 if (!sp)
113                         goto drop;
114                 if (skb->sp)
115                         secpath_put(skb->sp);
116                 skb->sp = sp;
117         }
118
119         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
120                 goto drop;
121
122         memcpy(skb->sp->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
123         skb->sp->len += xfrm_nr;
124         skb->ip_summed = CHECKSUM_NONE;
125
126         nf_reset(skb);
127
128         if (decaps) {
129                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
130                         dst_release(skb->dst);
131                         skb->dst = NULL;
132                 }
133                 netif_rx(skb);
134                 return -1;
135         } else {
136 #ifdef CONFIG_NETFILTER
137                 skb->nh.ipv6h->payload_len = htons(skb->len);
138                 __skb_push(skb, skb->data - skb->nh.raw);
139
140                 NF_HOOK(PF_INET6, NF_IP6_PRE_ROUTING, skb, skb->dev, NULL,
141                         ip6_rcv_finish);
142                 return -1;
143 #else
144                 return 1;
145 #endif
146         }
147
148 drop_unlock:
149         spin_unlock(&x->lock);
150         xfrm_state_put(x);
151 drop:
152         while (--xfrm_nr >= 0)
153                 xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
154         kfree_skb(skb);
155         return -1;
156 }
157
158 EXPORT_SYMBOL(xfrm6_rcv_spi);
159
160 int xfrm6_rcv(struct sk_buff **pskb)
161 {
162         return xfrm6_rcv_spi(pskb, 0);
163 }