[CRYPTO] twofish: Merge common glue code
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / ipv4 / xfrm4_input.c
blob5e95c8a07efbad59809f5370c62b317b58e1fe9c
1 /*
2 * xfrm4_input.c
4 * Changes:
5 * YOSHIFUJI Hideaki @USAGI
6 * Split up af-specific portion
7 * Derek Atkins <derek@ihtfp.com>
8 * Add Encapsulation support
12 #include <linux/module.h>
13 #include <linux/string.h>
14 #include <linux/netfilter.h>
15 #include <linux/netfilter_ipv4.h>
16 #include <net/ip.h>
17 #include <net/xfrm.h>
19 #ifdef CONFIG_NETFILTER
20 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
22 if (skb->dst == NULL) {
23 const struct iphdr *iph = ip_hdr(skb);
25 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
26 skb->dev))
27 goto drop;
29 return dst_input(skb);
30 drop:
31 kfree_skb(skb);
32 return NET_RX_DROP;
34 #endif
36 int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
37 int encap_type)
39 int err;
40 __be32 seq;
41 struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
42 struct xfrm_state *x;
43 int xfrm_nr = 0;
44 int decaps = 0;
45 unsigned int nhoff = offsetof(struct iphdr, protocol);
47 seq = 0;
48 if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
49 goto drop;
51 do {
52 const struct iphdr *iph = ip_hdr(skb);
54 if (xfrm_nr == XFRM_MAX_DEPTH)
55 goto drop;
57 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi,
58 nexthdr, AF_INET);
59 if (x == NULL)
60 goto drop;
62 spin_lock(&x->lock);
63 if (unlikely(x->km.state != XFRM_STATE_VALID))
64 goto drop_unlock;
66 if ((x->encap ? x->encap->encap_type : 0) != encap_type)
67 goto drop_unlock;
69 if (x->props.replay_window && xfrm_replay_check(x, seq))
70 goto drop_unlock;
72 if (xfrm_state_check_expire(x))
73 goto drop_unlock;
75 nexthdr = x->type->input(x, skb);
76 if (nexthdr <= 0)
77 goto drop_unlock;
79 skb_network_header(skb)[nhoff] = nexthdr;
81 /* only the first xfrm gets the encap type */
82 encap_type = 0;
84 if (x->props.replay_window)
85 xfrm_replay_advance(x, seq);
87 x->curlft.bytes += skb->len;
88 x->curlft.packets++;
90 spin_unlock(&x->lock);
92 xfrm_vec[xfrm_nr++] = x;
94 if (x->outer_mode->input(x, skb))
95 goto drop;
97 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
98 decaps = 1;
99 break;
102 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
103 if (err < 0)
104 goto drop;
105 } while (!err);
107 /* 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;
118 if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
119 goto drop;
121 memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
122 xfrm_nr * sizeof(xfrm_vec[0]));
123 skb->sp->len += xfrm_nr;
125 nf_reset(skb);
127 if (decaps) {
128 dst_release(skb->dst);
129 skb->dst = NULL;
130 netif_rx(skb);
131 return 0;
132 } else {
133 #ifdef CONFIG_NETFILTER
134 __skb_push(skb, skb->data - skb_network_header(skb));
135 ip_hdr(skb)->tot_len = htons(skb->len);
136 ip_send_check(ip_hdr(skb));
138 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
139 xfrm4_rcv_encap_finish);
140 return 0;
141 #else
142 return -ip_hdr(skb)->protocol;
143 #endif
146 drop_unlock:
147 spin_unlock(&x->lock);
148 xfrm_state_put(x);
149 drop:
150 while (--xfrm_nr >= 0)
151 xfrm_state_put(xfrm_vec[xfrm_nr]);
153 kfree_skb(skb);
154 return 0;
156 EXPORT_SYMBOL(xfrm4_rcv_encap);
158 /* If it's a keepalive packet, then just eat it.
159 * If it's an encapsulated packet, then pass it to the
160 * IPsec xfrm input.
161 * Returns 0 if skb passed to xfrm or was dropped.
162 * Returns >0 if skb should be passed to UDP.
163 * Returns <0 if skb should be resubmitted (-ret is protocol)
165 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
167 struct udp_sock *up = udp_sk(sk);
168 struct udphdr *uh;
169 struct iphdr *iph;
170 int iphlen, len;
171 int ret;
173 __u8 *udpdata;
174 __be32 *udpdata32;
175 __u16 encap_type = up->encap_type;
177 /* if this is not encapsulated socket, then just return now */
178 if (!encap_type)
179 return 1;
181 /* If this is a paged skb, make sure we pull up
182 * whatever data we need to look at. */
183 len = skb->len - sizeof(struct udphdr);
184 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
185 return 1;
187 /* Now we can get the pointers */
188 uh = udp_hdr(skb);
189 udpdata = (__u8 *)uh + sizeof(struct udphdr);
190 udpdata32 = (__be32 *)udpdata;
192 switch (encap_type) {
193 default:
194 case UDP_ENCAP_ESPINUDP:
195 /* Check if this is a keepalive packet. If so, eat it. */
196 if (len == 1 && udpdata[0] == 0xff) {
197 goto drop;
198 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
199 /* ESP Packet without Non-ESP header */
200 len = sizeof(struct udphdr);
201 } else
202 /* Must be an IKE packet.. pass it through */
203 return 1;
204 break;
205 case UDP_ENCAP_ESPINUDP_NON_IKE:
206 /* Check if this is a keepalive packet. If so, eat it. */
207 if (len == 1 && udpdata[0] == 0xff) {
208 goto drop;
209 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
210 udpdata32[0] == 0 && udpdata32[1] == 0) {
212 /* ESP Packet with Non-IKE marker */
213 len = sizeof(struct udphdr) + 2 * sizeof(u32);
214 } else
215 /* Must be an IKE packet.. pass it through */
216 return 1;
217 break;
220 /* At this point we are sure that this is an ESPinUDP packet,
221 * so we need to remove 'len' bytes from the packet (the UDP
222 * header and optional ESP marker bytes) and then modify the
223 * protocol to ESP, and then call into the transform receiver.
225 if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
226 goto drop;
228 /* Now we can update and verify the packet length... */
229 iph = ip_hdr(skb);
230 iphlen = iph->ihl << 2;
231 iph->tot_len = htons(ntohs(iph->tot_len) - len);
232 if (skb->len < iphlen + len) {
233 /* packet is too small!?! */
234 goto drop;
237 /* pull the data buffer up to the ESP header and set the
238 * transport header to point to ESP. Keep UDP on the stack
239 * for later.
241 __skb_pull(skb, len);
242 skb_reset_transport_header(skb);
244 /* process ESP */
245 ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
246 return ret;
248 drop:
249 kfree_skb(skb);
250 return 0;
253 int xfrm4_rcv(struct sk_buff *skb)
255 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
258 EXPORT_SYMBOL(xfrm4_rcv);