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,
44 XFRM_SPI_SKB_CB(skb)->nhoff = offsetof(struct iphdr, protocol);
45 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
46 return xfrm_input(skb, nexthdr, spi, encap_type);
48 EXPORT_SYMBOL(xfrm4_rcv_encap);
50 int xfrm4_transport_finish(struct sk_buff *skb, int async)
52 #ifdef CONFIG_NETFILTER
53 __skb_push(skb, skb->data - skb_network_header(skb));
54 ip_hdr(skb)->tot_len = htons(skb->len);
55 ip_send_check(ip_hdr(skb));
57 NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
58 xfrm4_rcv_encap_finish);
61 return -ip_hdr(skb)->protocol;
65 /* If it's a keepalive packet, then just eat it.
66 * If it's an encapsulated packet, then pass it to the
68 * Returns 0 if skb passed to xfrm or was dropped.
69 * Returns >0 if skb should be passed to UDP.
70 * Returns <0 if skb should be resubmitted (-ret is protocol)
72 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
74 struct udp_sock *up = udp_sk(sk);
82 __u16 encap_type = up->encap_type;
84 /* if this is not encapsulated socket, then just return now */
88 /* If this is a paged skb, make sure we pull up
89 * whatever data we need to look at. */
90 len = skb->len - sizeof(struct udphdr);
91 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
94 /* Now we can get the pointers */
96 udpdata = (__u8 *)uh + sizeof(struct udphdr);
97 udpdata32 = (__be32 *)udpdata;
101 case UDP_ENCAP_ESPINUDP:
102 /* Check if this is a keepalive packet. If so, eat it. */
103 if (len == 1 && udpdata[0] == 0xff) {
105 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
106 /* ESP Packet without Non-ESP header */
107 len = sizeof(struct udphdr);
109 /* Must be an IKE packet.. pass it through */
112 case UDP_ENCAP_ESPINUDP_NON_IKE:
113 /* Check if this is a keepalive packet. If so, eat it. */
114 if (len == 1 && udpdata[0] == 0xff) {
116 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
117 udpdata32[0] == 0 && udpdata32[1] == 0) {
119 /* ESP Packet with Non-IKE marker */
120 len = sizeof(struct udphdr) + 2 * sizeof(u32);
122 /* Must be an IKE packet.. pass it through */
127 /* At this point we are sure that this is an ESPinUDP packet,
128 * so we need to remove 'len' bytes from the packet (the UDP
129 * header and optional ESP marker bytes) and then modify the
130 * protocol to ESP, and then call into the transform receiver.
132 if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
135 /* Now we can update and verify the packet length... */
137 iphlen = iph->ihl << 2;
138 iph->tot_len = htons(ntohs(iph->tot_len) - len);
139 if (skb->len < iphlen + len) {
140 /* packet is too small!?! */
144 /* pull the data buffer up to the ESP header and set the
145 * transport header to point to ESP. Keep UDP on the stack
148 __skb_pull(skb, len);
149 skb_reset_transport_header(skb);
152 ret = xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
160 int xfrm4_rcv(struct sk_buff *skb)
162 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
165 EXPORT_SYMBOL(xfrm4_rcv);