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1d71627d MN |
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 <net/ipv6.h> | |
33 | #include <net/xfrm.h> | |
34 | ||
35 | /* Add route optimization header space. | |
36 | * | |
37 | * The IP header and mutable extension headers will be moved forward to make | |
38 | * space for the route optimization header. | |
39 | * | |
40 | * On exit, skb->h will be set to the start of the encapsulation header to be | |
41 | * filled in by x->type->output and skb->nh will be set to the nextheader field | |
42 | * of the extension header directly preceding the encapsulation header, or in | |
43 | * its absence, that of the top IP header. The value of skb->data will always | |
44 | * point to the top IP header. | |
45 | */ | |
46 | static int xfrm6_ro_output(struct sk_buff *skb) | |
47 | { | |
48 | struct xfrm_state *x = skb->dst->xfrm; | |
49 | struct ipv6hdr *iph; | |
50 | u8 *prevhdr; | |
51 | int hdr_len; | |
52 | ||
53 | skb_push(skb, x->props.header_len); | |
54 | iph = skb->nh.ipv6h; | |
55 | ||
56 | hdr_len = x->type->hdr_offset(x, skb, &prevhdr); | |
57 | skb->nh.raw = prevhdr - x->props.header_len; | |
58 | skb->h.raw = skb->data + hdr_len; | |
59 | memmove(skb->data, iph, hdr_len); | |
60 | return 0; | |
61 | } | |
62 | ||
63 | /* | |
64 | * Do nothing about routing optimization header unlike IPsec. | |
65 | */ | |
66 | static int xfrm6_ro_input(struct xfrm_state *x, struct sk_buff *skb) | |
67 | { | |
68 | return 0; | |
69 | } | |
70 | ||
71 | static struct xfrm_mode xfrm6_ro_mode = { | |
72 | .input = xfrm6_ro_input, | |
73 | .output = xfrm6_ro_output, | |
74 | .owner = THIS_MODULE, | |
75 | .encap = XFRM_MODE_ROUTEOPTIMIZATION, | |
76 | }; | |
77 | ||
78 | static int __init xfrm6_ro_init(void) | |
79 | { | |
80 | return xfrm_register_mode(&xfrm6_ro_mode, AF_INET6); | |
81 | } | |
82 | ||
83 | static void __exit xfrm6_ro_exit(void) | |
84 | { | |
85 | int err; | |
86 | ||
87 | err = xfrm_unregister_mode(&xfrm6_ro_mode, AF_INET6); | |
88 | BUG_ON(err); | |
89 | } | |
90 | ||
91 | module_init(xfrm6_ro_init); | |
92 | module_exit(xfrm6_ro_exit); | |
93 | MODULE_LICENSE("GPL"); | |
94 | MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_ROUTEOPTIMIZATION); |