linux/net/ipv6/xfrm6_mode_ro.c
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   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/spinlock.h>
  32#include <linux/stringify.h>
  33#include <linux/time.h>
  34#include <net/ipv6.h>
  35#include <net/xfrm.h>
  36
  37/* Add route optimization header space.
  38 *
  39 * The IP header and mutable extension headers will be moved forward to make
  40 * space for the route optimization header.
  41 */
  42static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
  43{
  44        struct ipv6hdr *iph;
  45        u8 *prevhdr;
  46        int hdr_len;
  47
  48        iph = ipv6_hdr(skb);
  49
  50        hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
  51        skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
  52        skb_set_network_header(skb, -x->props.header_len);
  53        skb->transport_header = skb->network_header + hdr_len;
  54        __skb_pull(skb, hdr_len);
  55        memmove(ipv6_hdr(skb), iph, hdr_len);
  56
  57        x->lastused = get_seconds();
  58
  59        return 0;
  60}
  61
  62static struct xfrm_mode xfrm6_ro_mode = {
  63        .output = xfrm6_ro_output,
  64        .owner = THIS_MODULE,
  65        .encap = XFRM_MODE_ROUTEOPTIMIZATION,
  66};
  67
  68static int __init xfrm6_ro_init(void)
  69{
  70        return xfrm_register_mode(&xfrm6_ro_mode, AF_INET6);
  71}
  72
  73static void __exit xfrm6_ro_exit(void)
  74{
  75        int err;
  76
  77        err = xfrm_unregister_mode(&xfrm6_ro_mode, AF_INET6);
  78        BUG_ON(err);
  79}
  80
  81module_init(xfrm6_ro_init);
  82module_exit(xfrm6_ro_exit);
  83MODULE_LICENSE("GPL");
  84MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_ROUTEOPTIMIZATION);
  85
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