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 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
26 if (skb->dst == NULL) {
27 const struct iphdr *iph = ip_hdr(skb);
29 if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
33 return dst_input(skb);
39 int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
42 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
43 return xfrm_input(skb, nexthdr, spi, encap_type);
45 EXPORT_SYMBOL(xfrm4_rcv_encap);
47 int xfrm4_transport_finish(struct sk_buff *skb, int async)
49 struct iphdr *iph = ip_hdr(skb);
51 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
53 #ifdef CONFIG_NETFILTER
54 __skb_push(skb, skb->data - skb_network_header(skb));
55 iph->tot_len = htons(skb->len);
58 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
59 xfrm4_rcv_encap_finish);
63 return xfrm4_rcv_encap_finish(skb);
65 return -iph->protocol;
69 /* If it's a keepalive packet, then just eat it.
70 * If it's an encapsulated packet, then pass it to the
72 * Returns 0 if skb passed to xfrm or was dropped.
73 * Returns >0 if skb should be passed to UDP.
74 * Returns <0 if skb should be resubmitted (-ret is protocol)
76 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
78 struct udp_sock *up = udp_sk(sk);
86 __u16 encap_type = up->encap_type;
88 /* if this is not encapsulated socket, then just return now */
92 /* If this is a paged skb, make sure we pull up
93 * whatever data we need to look at. */
94 len = skb->len - sizeof(struct udphdr);
95 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
98 /* Now we can get the pointers */
100 udpdata = (__u8 *)uh + sizeof(struct udphdr);
101 udpdata32 = (__be32 *)udpdata;
103 switch (encap_type) {
105 case UDP_ENCAP_ESPINUDP:
106 /* Check if this is a keepalive packet. If so, eat it. */
107 if (len == 1 && udpdata[0] == 0xff) {
109 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
110 /* ESP Packet without Non-ESP header */
111 len = sizeof(struct udphdr);
113 /* Must be an IKE packet.. pass it through */
116 case UDP_ENCAP_ESPINUDP_NON_IKE:
117 /* Check if this is a keepalive packet. If so, eat it. */
118 if (len == 1 && udpdata[0] == 0xff) {
120 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
121 udpdata32[0] == 0 && udpdata32[1] == 0) {
123 /* ESP Packet with Non-IKE marker */
124 len = sizeof(struct udphdr) + 2 * sizeof(u32);
126 /* Must be an IKE packet.. pass it through */
131 /* At this point we are sure that this is an ESPinUDP packet,
132 * so we need to remove 'len' bytes from the packet (the UDP
133 * header and optional ESP marker bytes) and then modify the
134 * protocol to ESP, and then call into the transform receiver.
136 if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
139 /* Now we can update and verify the packet length... */
141 iphlen = iph->ihl << 2;
142 iph->tot_len = htons(ntohs(iph->tot_len) - len);
143 if (skb->len < iphlen + len) {
144 /* packet is too small!?! */
148 /* pull the data buffer up to the ESP header and set the
149 * transport header to point to ESP. Keep UDP on the stack
152 __skb_pull(skb, len);
153 skb_reset_transport_header(skb);
156 ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
164 int xfrm4_rcv(struct sk_buff *skb)
166 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
169 EXPORT_SYMBOL(xfrm4_rcv);