5 * YOSHIFUJI Hideaki @USAGI
6 * Split up af-specific portion
7 * Derek Atkins <derek@ihtfp.com>
8 * Add Encapsulation support
12 #include <linux/slab.h>
13 #include <linux/module.h>
14 #include <linux/string.h>
15 #include <linux/netfilter.h>
16 #include <linux/netfilter_ipv4.h>
20 int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb)
22 return xfrm4_extract_header(skb);
25 static int xfrm4_rcv_encap_finish2(struct sk_buff *skb)
27 return dst_input(skb);
30 static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
32 if (skb_dst(skb) == NULL) {
33 const struct iphdr *iph = ip_hdr(skb);
35 if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
40 if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
49 int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
52 XFRM_SPI_SKB_CB(skb)->family = AF_INET;
53 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
54 return xfrm_input(skb, nexthdr, spi, encap_type);
56 EXPORT_SYMBOL(xfrm4_rcv_encap);
58 int xfrm4_transport_finish(struct sk_buff *skb, int async)
60 struct iphdr *iph = ip_hdr(skb);
62 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
64 #ifndef CONFIG_NETFILTER
66 return -iph->protocol;
69 __skb_push(skb, skb->data - skb_network_header(skb));
70 iph->tot_len = htons(skb->len);
73 NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
74 xfrm4_rcv_encap_finish);
78 /* If it's a keepalive packet, then just eat it.
79 * If it's an encapsulated packet, then pass it to the
81 * Returns 0 if skb passed to xfrm or was dropped.
82 * Returns >0 if skb should be passed to UDP.
83 * Returns <0 if skb should be resubmitted (-ret is protocol)
85 int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
87 struct udp_sock *up = udp_sk(sk);
94 __u16 encap_type = up->encap_type;
96 /* if this is not encapsulated socket, then just return now */
100 /* If this is a paged skb, make sure we pull up
101 * whatever data we need to look at. */
102 len = skb->len - sizeof(struct udphdr);
103 if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
106 /* Now we can get the pointers */
108 udpdata = (__u8 *)uh + sizeof(struct udphdr);
109 udpdata32 = (__be32 *)udpdata;
111 switch (encap_type) {
113 case UDP_ENCAP_ESPINUDP:
114 /* Check if this is a keepalive packet. If so, eat it. */
115 if (len == 1 && udpdata[0] == 0xff) {
117 } else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
118 /* ESP Packet without Non-ESP header */
119 len = sizeof(struct udphdr);
121 /* Must be an IKE packet.. pass it through */
124 case UDP_ENCAP_ESPINUDP_NON_IKE:
125 /* Check if this is a keepalive packet. If so, eat it. */
126 if (len == 1 && udpdata[0] == 0xff) {
128 } else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
129 udpdata32[0] == 0 && udpdata32[1] == 0) {
131 /* ESP Packet with Non-IKE marker */
132 len = sizeof(struct udphdr) + 2 * sizeof(u32);
134 /* Must be an IKE packet.. pass it through */
139 /* At this point we are sure that this is an ESPinUDP packet,
140 * so we need to remove 'len' bytes from the packet (the UDP
141 * header and optional ESP marker bytes) and then modify the
142 * protocol to ESP, and then call into the transform receiver.
144 if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
147 /* Now we can update and verify the packet length... */
149 iphlen = iph->ihl << 2;
150 iph->tot_len = htons(ntohs(iph->tot_len) - len);
151 if (skb->len < iphlen + len) {
152 /* packet is too small!?! */
156 /* pull the data buffer up to the ESP header and set the
157 * transport header to point to ESP. Keep UDP on the stack
160 __skb_pull(skb, len);
161 skb_reset_transport_header(skb);
164 return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
171 int xfrm4_rcv(struct sk_buff *skb)
173 return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
175 EXPORT_SYMBOL(xfrm4_rcv);