[IPSEC]: Merge most of the input path
[linux-2.6.git] / net / xfrm / xfrm_input.c
1 /*
2  * xfrm_input.c
3  *
4  * Changes:
5  *      YOSHIFUJI Hideaki @USAGI
6  *              Split up af-specific portion
7  *
8  */
9
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/netdevice.h>
13 #include <net/dst.h>
14 #include <net/ip.h>
15 #include <net/xfrm.h>
16
17 static struct kmem_cache *secpath_cachep __read_mostly;
18
19 void __secpath_destroy(struct sec_path *sp)
20 {
21         int i;
22         for (i = 0; i < sp->len; i++)
23                 xfrm_state_put(sp->xvec[i]);
24         kmem_cache_free(secpath_cachep, sp);
25 }
26 EXPORT_SYMBOL(__secpath_destroy);
27
28 struct sec_path *secpath_dup(struct sec_path *src)
29 {
30         struct sec_path *sp;
31
32         sp = kmem_cache_alloc(secpath_cachep, GFP_ATOMIC);
33         if (!sp)
34                 return NULL;
35
36         sp->len = 0;
37         if (src) {
38                 int i;
39
40                 memcpy(sp, src, sizeof(*sp));
41                 for (i = 0; i < sp->len; i++)
42                         xfrm_state_hold(sp->xvec[i]);
43         }
44         atomic_set(&sp->refcnt, 1);
45         return sp;
46 }
47 EXPORT_SYMBOL(secpath_dup);
48
49 /* Fetch spi and seq from ipsec header */
50
51 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
52 {
53         int offset, offset_seq;
54         int hlen;
55
56         switch (nexthdr) {
57         case IPPROTO_AH:
58                 hlen = sizeof(struct ip_auth_hdr);
59                 offset = offsetof(struct ip_auth_hdr, spi);
60                 offset_seq = offsetof(struct ip_auth_hdr, seq_no);
61                 break;
62         case IPPROTO_ESP:
63                 hlen = sizeof(struct ip_esp_hdr);
64                 offset = offsetof(struct ip_esp_hdr, spi);
65                 offset_seq = offsetof(struct ip_esp_hdr, seq_no);
66                 break;
67         case IPPROTO_COMP:
68                 if (!pskb_may_pull(skb, sizeof(struct ip_comp_hdr)))
69                         return -EINVAL;
70                 *spi = htonl(ntohs(*(__be16*)(skb_transport_header(skb) + 2)));
71                 *seq = 0;
72                 return 0;
73         default:
74                 return 1;
75         }
76
77         if (!pskb_may_pull(skb, hlen))
78                 return -EINVAL;
79
80         *spi = *(__be32*)(skb_transport_header(skb) + offset);
81         *seq = *(__be32*)(skb_transport_header(skb) + offset_seq);
82         return 0;
83 }
84 EXPORT_SYMBOL(xfrm_parse_spi);
85
86 int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
87 {
88         int err;
89
90         err = x->outer_mode->afinfo->extract_input(x, skb);
91         if (err)
92                 return err;
93
94         skb->protocol = x->inner_mode->afinfo->eth_proto;
95         return x->inner_mode->input2(x, skb);
96 }
97 EXPORT_SYMBOL(xfrm_prepare_input);
98
99 int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
100 {
101         int err;
102         __be32 seq;
103         struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
104         struct xfrm_state *x;
105         int xfrm_nr = 0;
106         int decaps = 0;
107         unsigned int nhoff = XFRM_SPI_SKB_CB(skb)->nhoff;
108         unsigned int daddroff = XFRM_SPI_SKB_CB(skb)->daddroff;
109
110         seq = 0;
111         if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
112                 goto drop;
113
114         do {
115                 if (xfrm_nr == XFRM_MAX_DEPTH)
116                         goto drop;
117
118                 x = xfrm_state_lookup((xfrm_address_t *)
119                                       (skb_network_header(skb) + daddroff),
120                                       spi, nexthdr, AF_INET);
121                 if (x == NULL)
122                         goto drop;
123
124                 spin_lock(&x->lock);
125                 if (unlikely(x->km.state != XFRM_STATE_VALID))
126                         goto drop_unlock;
127
128                 if ((x->encap ? x->encap->encap_type : 0) != encap_type)
129                         goto drop_unlock;
130
131                 if (x->props.replay_window && xfrm_replay_check(x, seq))
132                         goto drop_unlock;
133
134                 if (xfrm_state_check_expire(x))
135                         goto drop_unlock;
136
137                 nexthdr = x->type->input(x, skb);
138                 if (nexthdr <= 0)
139                         goto drop_unlock;
140
141                 skb_network_header(skb)[nhoff] = nexthdr;
142
143                 /* only the first xfrm gets the encap type */
144                 encap_type = 0;
145
146                 if (x->props.replay_window)
147                         xfrm_replay_advance(x, seq);
148
149                 x->curlft.bytes += skb->len;
150                 x->curlft.packets++;
151
152                 spin_unlock(&x->lock);
153
154                 xfrm_vec[xfrm_nr++] = x;
155
156                 if (x->inner_mode->input(x, skb))
157                         goto drop;
158
159                 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
160                         decaps = 1;
161                         break;
162                 }
163
164                 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
165                 if (err < 0)
166                         goto drop;
167         } while (!err);
168
169         /* Allocate new secpath or COW existing one. */
170
171         if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
172                 struct sec_path *sp;
173                 sp = secpath_dup(skb->sp);
174                 if (!sp)
175                         goto drop;
176                 if (skb->sp)
177                         secpath_put(skb->sp);
178                 skb->sp = sp;
179         }
180         if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
181                 goto drop;
182
183         memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
184                xfrm_nr * sizeof(xfrm_vec[0]));
185         skb->sp->len += xfrm_nr;
186
187         nf_reset(skb);
188
189         if (decaps) {
190                 dst_release(skb->dst);
191                 skb->dst = NULL;
192                 netif_rx(skb);
193                 return 0;
194         } else {
195                 return x->inner_mode->afinfo->transport_finish(skb, 0);
196         }
197
198 drop_unlock:
199         spin_unlock(&x->lock);
200         xfrm_state_put(x);
201 drop:
202         while (--xfrm_nr >= 0)
203                 xfrm_state_put(xfrm_vec[xfrm_nr]);
204
205         kfree_skb(skb);
206         return 0;
207 }
208 EXPORT_SYMBOL(xfrm_input);
209
210 void __init xfrm_input_init(void)
211 {
212         secpath_cachep = kmem_cache_create("secpath_cache",
213                                            sizeof(struct sec_path),
214                                            0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
215                                            NULL);
216 }