2 * xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
4 * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
5 * Miika Komu <miika@iki.fi>
6 * Herbert Xu <herbert@gondor.apana.org.au>
7 * Abhinav Pathak <abhinav.pathak@hiit.fi>
8 * Jeff Ahrenholz <ahrenholz@gmail.com>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/stringify.h>
16 #include <net/dsfield.h>
18 #include <net/inet_ecn.h>
22 /* Add encapsulation header.
24 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
25 * The following fields in it shall be filled in by x->type->output:
28 * On exit, skb->h will be set to the start of the encapsulation header to be
29 * filled in by x->type->output and the mac header will be set to the
30 * nextheader field of the extension header directly preceding the
31 * encapsulation header, or in its absence, that of the top IP header.
32 * The value of the network header will always point to the top IP header
33 * while skb->data will point to the payload.
35 static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
37 struct ipv6hdr *iph, *top_iph;
43 hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
45 skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
46 skb_set_network_header(skb, -x->props.header_len);
47 skb_set_transport_header(skb, hdr_len - x->props.header_len);
48 __skb_pull(skb, hdr_len);
50 top_iph = ipv6_hdr(skb);
51 memmove(top_iph, iph, hdr_len);
53 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
54 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
59 static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
62 const unsigned char *old_mac;
63 int size = sizeof(struct ipv6hdr);
66 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
70 memmove(skb->data, skb_network_header(skb), size);
71 skb_reset_network_header(skb);
73 old_mac = skb_mac_header(skb);
74 skb_set_mac_header(skb, -skb->mac_len);
75 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
78 ip6h->payload_len = htons(skb->len - size);
79 ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
80 ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
86 static struct xfrm_mode xfrm6_beet_mode = {
87 .input = xfrm6_beet_input,
88 .output = xfrm6_beet_output,
90 .encap = XFRM_MODE_BEET,
93 static int __init xfrm6_beet_init(void)
95 return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
98 static void __exit xfrm6_beet_exit(void)
102 err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
106 module_init(xfrm6_beet_init);
107 module_exit(xfrm6_beet_exit);
108 MODULE_LICENSE("GPL");
109 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);