xfrm6_mode_ro.c revision ca68145f16359f71cd62b2671aa3e8c58f45ef19 
1/*
2 * xfrm6_mode_ro.c - Route optimization mode for IPv6.
3 *
4 * Copyright (C)2003-2006 Helsinki University of Technology
5 * Copyright (C)2003-2006 USAGI/WIDE Project
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20 */
21/*
22 * Authors:
23 *	Noriaki TAKAMIYA @USAGI
24 *	Masahide NAKAMURA @USAGI
25 */
26
27#include <linux/init.h>
28#include <linux/kernel.h>
29#include <linux/module.h>
30#include <linux/skbuff.h>
31#include <linux/stringify.h>
32#include <linux/time.h>
33#include <net/ipv6.h>
34#include <net/xfrm.h>
35
36/* Add route optimization header space.
37 *
38 * The IP header and mutable extension headers will be moved forward to make
39 * space for the route optimization header.
40 */
41static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
42{
43	struct ipv6hdr *iph;
44	u8 *prevhdr;
45	int hdr_len;
46
47	iph = ipv6_hdr(skb);
48
49	hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
50	skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
51	skb_set_network_header(skb, -x->props.header_len);
52	skb->transport_header = skb->network_header + hdr_len;
53	__skb_pull(skb, hdr_len);
54	memmove(ipv6_hdr(skb), iph, hdr_len);
55
56	x->lastused = get_seconds();
57
58	return 0;
59}
60
61static struct xfrm_mode xfrm6_ro_mode = {
62	.output = xfrm6_ro_output,
63	.owner = THIS_MODULE,
64	.encap = XFRM_MODE_ROUTEOPTIMIZATION,
65};
66
67static int __init xfrm6_ro_init(void)
68{
69	return xfrm_register_mode(&xfrm6_ro_mode, AF_INET6);
70}
71
72static void __exit xfrm6_ro_exit(void)
73{
74	int err;
75
76	err = xfrm_unregister_mode(&xfrm6_ro_mode, AF_INET6);
77	BUG_ON(err);
78}
79
80module_init(xfrm6_ro_init);
81module_exit(xfrm6_ro_exit);
82MODULE_LICENSE("GPL");
83MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_ROUTEOPTIMIZATION);
84