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/*
* xfrm6_mode_ro.c - Route optimization mode for IPv6.
*
* Copyright (C)2003-2006 Helsinki University of Technology
* Copyright (C)2003-2006 USAGI/WIDE Project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Authors:
* Noriaki TAKAMIYA @USAGI
* Masahide NAKAMURA @USAGI
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <linux/time.h>
#include <net/ipv6.h>
#include <net/xfrm.h>
/* Add route optimization header space.
*
* The IP header and mutable extension headers will be moved forward to make
* space for the route optimization header.
*
* On exit, skb->h will be set to the start of the encapsulation header to be
* filled in by x->type->output and the mac header will be set to the
* nextheader field of the extension header directly preceding the
* encapsulation header, or in its absence, that of the top IP header.
* The value of the network header will always point to the top IP header
* while skb->data will point to the payload.
*/
static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *iph;
u8 *prevhdr;
int hdr_len;
iph = ipv6_hdr(skb);
hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
skb_set_network_header(skb, -x->props.header_len);
skb_set_transport_header(skb, hdr_len - x->props.header_len);
__skb_pull(skb, hdr_len);
memmove(ipv6_hdr(skb), iph, hdr_len);
x->lastused = get_seconds();
return 0;
}
/*
* Do nothing about routing optimization header unlike IPsec.
*/
static int xfrm6_ro_input(struct xfrm_state *x, struct sk_buff *skb)
{
return 0;
}
static struct xfrm_mode xfrm6_ro_mode = {
.input = xfrm6_ro_input,
.output = xfrm6_ro_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_ROUTEOPTIMIZATION,
};
static int __init xfrm6_ro_init(void)
{
return xfrm_register_mode(&xfrm6_ro_mode, AF_INET6);
}
static void __exit xfrm6_ro_exit(void)
{
int err;
err = xfrm_unregister_mode(&xfrm6_ro_mode, AF_INET6);
BUG_ON(err);
}
module_init(xfrm6_ro_init);
module_exit(xfrm6_ro_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_ROUTEOPTIMIZATION);
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