1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
/*
* xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
*
* Copyright (C) 2002 USAGI/WIDE Project
* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/xfrm.h>
/* Add encapsulation header.
*
* The IP header and mutable extension headers will be moved forward to make
* space for the encapsulation 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_transport_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);
return 0;
}
/* Remove encapsulation header.
*
* The IP header will be moved over the top of the encapsulation header.
*
* On entry, skb->h shall point to where the IP header should be and skb->nh
* shall be set to where the IP header currently is. skb->data shall point
* to the start of the payload.
*/
static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
{
int ihl = skb->data - skb_transport_header(skb);
if (skb->transport_header != skb->network_header) {
memmove(skb_transport_header(skb),
skb_network_header(skb), ihl);
skb->network_header = skb->transport_header;
}
ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
sizeof(struct ipv6hdr));
skb_reset_transport_header(skb);
return 0;
}
static struct xfrm_mode xfrm6_transport_mode = {
.input = xfrm6_transport_input,
.output = xfrm6_transport_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_TRANSPORT,
};
static int __init xfrm6_transport_init(void)
{
return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
}
static void __exit xfrm6_transport_exit(void)
{
int err;
err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
BUG_ON(err);
}
module_init(xfrm6_transport_init);
module_exit(xfrm6_transport_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);
|
