[IPSEC]: Kill unused decap state structure
[linux-2.6.git] / net / ipv4 / xfrm4_input.c
1 /*
2  * xfrm4_input.c
3  *
4  * Changes:
5  *      YOSHIFUJI Hideaki @USAGI
6  *              Split up af-specific portion
7  *      Derek Atkins <derek@ihtfp.com>
8  *              Add Encapsulation support
9  *      
10  */
11
12 #include <linux/module.h>
13 #include <linux/string.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_ipv4.h>
16 #include <net/inet_ecn.h>
17 #include <net/ip.h>
18 #include <net/xfrm.h>
19
20 int xfrm4_rcv(struct sk_buff *skb)
21 {
22         return xfrm4_rcv_encap(skb, 0);
23 }
24
25 EXPORT_SYMBOL(xfrm4_rcv);
26
27 static inline void ipip_ecn_decapsulate(struct sk_buff *skb)
28 {
29         struct iphdr *outer_iph = skb->nh.iph;
30         struct iphdr *inner_iph = skb->h.ipiph;
31
32         if (INET_ECN_is_ce(outer_iph->tos))
33                 IP_ECN_set_ce(inner_iph);
34 }
35
36 static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq)
37 {
38         switch (nexthdr) {
39         case IPPROTO_IPIP:
40                 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
41                         return -EINVAL;
42                 *spi = skb->nh.iph->saddr;
43                 *seq = 0;
44                 return 0;
45         }
46
47         return xfrm_parse_spi(skb, nexthdr, spi, seq);
48 }
49
50 #ifdef CONFIG_NETFILTER
51 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
52 {
53         struct iphdr *iph = skb->nh.iph;
54
55         if (skb->dst == NULL) {
56                 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
57                                    skb->dev))
58                         goto drop;
59         }
60         return dst_input(skb);
61 drop:
62         kfree_skb(skb);
63         return NET_RX_DROP;
64 }
65 #endif
66
67 int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
68 {
69         int err;
70         u32 spi, seq;
71         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
72         struct xfrm_state *x;
73         int xfrm_nr = 0;
74         int decaps = 0;
75
76         if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
77                 goto drop;
78
79         do {
80                 struct iphdr *iph = skb->nh.iph;
81
82                 if (xfrm_nr == XFRM_MAX_DEPTH)
83                         goto drop;
84
85                 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, AF_INET);
86                 if (x == NULL)
87                         goto drop;
88
89                 spin_lock(&x->lock);
90                 if (unlikely(x->km.state != XFRM_STATE_VALID))
91                         goto drop_unlock;
92
93                 if (x->encap->encap_type != encap_type)
94                         goto drop_unlock;
95
96                 if (x->props.replay_window && xfrm_replay_check(x, seq))
97                         goto drop_unlock;
98
99                 if (xfrm_state_check_expire(x))
100                         goto drop_unlock;
101
102                 if (x->type->input(x, skb))
103                         goto drop_unlock;
104
105                 /* only the first xfrm gets the encap type */
106                 encap_type = 0;
107
108                 if (x->props.replay_window)
109                         xfrm_replay_advance(x, seq);
110
111                 x->curlft.bytes += skb->len;
112                 x->curlft.packets++;
113
114                 spin_unlock(&x->lock);
115
116                 xfrm_vec[xfrm_nr++] = x;
117
118                 iph = skb->nh.iph;
119
120                 if (x->props.mode) {
121                         if (iph->protocol != IPPROTO_IPIP)
122                                 goto drop;
123                         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
124                                 goto drop;
125                         if (skb_cloned(skb) &&
126                             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
127                                 goto drop;
128                         if (x->props.flags & XFRM_STATE_DECAP_DSCP)
129                                 ipv4_copy_dscp(iph, skb->h.ipiph);
130                         if (!(x->props.flags & XFRM_STATE_NOECN))
131                                 ipip_ecn_decapsulate(skb);
132                         skb->mac.raw = memmove(skb->data - skb->mac_len,
133                                                skb->mac.raw, skb->mac_len);
134                         skb->nh.raw = skb->data;
135                         memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
136                         decaps = 1;
137                         break;
138                 }
139
140                 if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 0)
141                         goto drop;
142         } while (!err);
143
144         /* Allocate new secpath or COW existing one. */
145
146         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
147                 struct sec_path *sp;
148                 sp = secpath_dup(skb->sp);
149                 if (!sp)
150                         goto drop;
151                 if (skb->sp)
152                         secpath_put(skb->sp);
153                 skb->sp = sp;
154         }
155         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
156                 goto drop;
157
158         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
159                xfrm_nr * sizeof(xfrm_vec[0]));
160         skb->sp->len += xfrm_nr;
161
162         nf_reset(skb);
163
164         if (decaps) {
165                 if (!(skb->dev->flags&IFF_LOOPBACK)) {
166                         dst_release(skb->dst);
167                         skb->dst = NULL;
168                 }
169                 netif_rx(skb);
170                 return 0;
171         } else {
172 #ifdef CONFIG_NETFILTER
173                 __skb_push(skb, skb->data - skb->nh.raw);
174                 skb->nh.iph->tot_len = htons(skb->len);
175                 ip_send_check(skb->nh.iph);
176
177                 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
178                         xfrm4_rcv_encap_finish);
179                 return 0;
180 #else
181                 return -skb->nh.iph->protocol;
182 #endif
183         }
184
185 drop_unlock:
186         spin_unlock(&x->lock);
187         xfrm_state_put(x);
188 drop:
189         while (--xfrm_nr >= 0)
190                 xfrm_state_put(xfrm_vec[xfrm_nr]);
191
192         kfree_skb(skb);
193         return 0;
194 }