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>
19 int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
21 return xfrm4_extract_header(skb);
24 #ifdef CONFIG_NETFILTER
25 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
27 if (skb->dst == NULL) {
28 const struct iphdr *iph = ip_hdr(skb);
30 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
34 return dst_input(skb);
41 int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
46 struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
50 unsigned int nhoff = offsetof(struct iphdr, protocol);
53 if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
57 const struct iphdr *iph = ip_hdr(skb);
59 if (xfrm_nr == XFRM_MAX_DEPTH)
62 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi,
68 if (unlikely(x->km.state != XFRM_STATE_VALID))
71 if ((x->encap ? x->encap->encap_type : 0) != encap_type)
74 if (x->props.replay_window && xfrm_replay_check(x, seq))
77 if (xfrm_state_check_expire(x))
80 nexthdr = x->type->input(x, skb);
84 skb_network_header(skb)[nhoff] = nexthdr;
86 /* only the first xfrm gets the encap type */
89 if (x->props.replay_window)
90 xfrm_replay_advance(x, seq);
92 x->curlft.bytes += skb->len;
95 spin_unlock(&x->lock);
97 xfrm_vec[xfrm_nr++] = x;
99 if (x->inner_mode->input(x, skb))
102 if (x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL) {
107 err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
112 /* Allocate new secpath or COW existing one. */
114 if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
116 sp = secpath_dup(skb->sp);
120 secpath_put(skb->sp);
123 if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
126 memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
127 xfrm_nr * sizeof(xfrm_vec[0]));
128 skb->sp->len += xfrm_nr;
133 dst_release(skb->dst);
138 #ifdef CONFIG_NETFILTER
139 __skb_push(skb, skb->data - skb_network_header(skb));
140 ip_hdr(skb)->tot_len = htons(skb->len);
141 ip_send_check(ip_hdr(skb));
143 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
144 xfrm4_rcv_encap_finish);
147 return -ip_hdr(skb)->protocol;
152 spin_unlock(&x->lock);
155 while (--xfrm_nr >= 0)
156 xfrm_state_put(xfrm_vec[xfrm_nr]);
161 EXPORT_SYMBOL(xfrm4_rcv_encap);
163 /* If it's a keepalive packet, then just eat it.
164 * If it's an encapsulated packet, then pass it to the
166 * Returns 0 if skb passed to xfrm or was dropped.
167 * Returns >0 if skb should be passed to UDP.
168 * Returns <0 if skb should be resubmitted (-ret is protocol)
170 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
172 struct udp_sock *up = udp_sk(sk);
180 __u16 encap_type = up->encap_type;
182 /* if this is not encapsulated socket, then just return now */
186 /* If this is a paged skb, make sure we pull up
187 * whatever data we need to look at. */
188 len = skb->len - sizeof(struct udphdr);
189 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
192 /* Now we can get the pointers */
194 udpdata = (__u8 *)uh + sizeof(struct udphdr);
195 udpdata32 = (__be32 *)udpdata;
197 switch (encap_type) {
199 case UDP_ENCAP_ESPINUDP:
200 /* Check if this is a keepalive packet. If so, eat it. */
201 if (len == 1 && udpdata[0] == 0xff) {
203 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
204 /* ESP Packet without Non-ESP header */
205 len = sizeof(struct udphdr);
207 /* Must be an IKE packet.. pass it through */
210 case UDP_ENCAP_ESPINUDP_NON_IKE:
211 /* Check if this is a keepalive packet. If so, eat it. */
212 if (len == 1 && udpdata[0] == 0xff) {
214 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
215 udpdata32[0] == 0 && udpdata32[1] == 0) {
217 /* ESP Packet with Non-IKE marker */
218 len = sizeof(struct udphdr) + 2 * sizeof(u32);
220 /* Must be an IKE packet.. pass it through */
225 /* At this point we are sure that this is an ESPinUDP packet,
226 * so we need to remove 'len' bytes from the packet (the UDP
227 * header and optional ESP marker bytes) and then modify the
228 * protocol to ESP, and then call into the transform receiver.
230 if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
233 /* Now we can update and verify the packet length... */
235 iphlen = iph->ihl << 2;
236 iph->tot_len = htons(ntohs(iph->tot_len) - len);
237 if (skb->len < iphlen + len) {
238 /* packet is too small!?! */
242 /* pull the data buffer up to the ESP header and set the
243 * transport header to point to ESP. Keep UDP on the stack
246 __skb_pull(skb, len);
247 skb_reset_transport_header(skb);
250 ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
258 int xfrm4_rcv(struct sk_buff *skb)
260 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
263 EXPORT_SYMBOL(xfrm4_rcv);