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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
* xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
*
* Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
* Miika Komu <miika@iki.fi>
* Herbert Xu <herbert@gondor.apana.org.au>
* Abhinav Pathak <abhinav.pathak@hiit.fi>
* Jeff Ahrenholz <ahrenholz@gmail.com>
*/
#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/ip.h>
#include <net/xfrm.h>
/* Add encapsulation header.
*
* The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
* The following fields in it shall be filled in by x->type->output:
* tot_len
* check
*
* On exit, skb->h will be set to the start of the payload to be processed
* by x->type->output and skb->nh will be set to the top IP header.
*/
static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct iphdr *iph, *top_iph = NULL;
int hdrlen, optlen;
iph = ip_hdr(skb);
skb->h.raw = skb->nh.raw;
hdrlen = 0;
optlen = iph->ihl * 4 - sizeof(*iph);
if (unlikely(optlen))
hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
skb_push(skb, x->props.header_len + hdrlen);
skb_reset_network_header(skb);
top_iph = ip_hdr(skb);
skb->h.raw += sizeof(*iph) - hdrlen;
memmove(top_iph, iph, sizeof(*iph));
if (unlikely(optlen)) {
struct ip_beet_phdr *ph;
BUG_ON(optlen < 0);
ph = (struct ip_beet_phdr *)skb->h.raw;
ph->padlen = 4 - (optlen & 4);
ph->hdrlen = optlen / 8;
ph->nexthdr = top_iph->protocol;
if (ph->padlen)
memset(ph + 1, IPOPT_NOP, ph->padlen);
top_iph->protocol = IPPROTO_BEETPH;
top_iph->ihl = sizeof(struct iphdr) / 4;
}
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
return 0;
}
static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct iphdr *iph = ip_hdr(skb);
int phlen = 0;
int optlen = 0;
__u8 ph_nexthdr = 0, protocol = 0;
int err = -EINVAL;
protocol = iph->protocol;
if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
struct ip_beet_phdr *ph;
if (!pskb_may_pull(skb, sizeof(*ph)))
goto out;
ph = (struct ip_beet_phdr *)(skb->h.ipiph + 1);
phlen = sizeof(*ph) + ph->padlen;
optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
if (optlen < 0 || optlen & 3 || optlen > 250)
goto out;
if (!pskb_may_pull(skb, phlen + optlen))
goto out;
skb->len -= phlen + optlen;
ph_nexthdr = ph->nexthdr;
}
skb->nh.raw = skb->data + (phlen - sizeof(*iph));
memmove(skb_network_header(skb), iph, sizeof(*iph));
skb->h.raw = skb->data + (phlen + optlen);
skb->data = skb->h.raw;
iph = ip_hdr(skb);
iph->ihl = (sizeof(*iph) + optlen) / 4;
iph->tot_len = htons(skb->len + iph->ihl * 4);
iph->daddr = x->sel.daddr.a4;
iph->saddr = x->sel.saddr.a4;
if (ph_nexthdr)
iph->protocol = ph_nexthdr;
else
iph->protocol = protocol;
iph->check = 0;
iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
err = 0;
out:
return err;
}
static struct xfrm_mode xfrm4_beet_mode = {
.input = xfrm4_beet_input,
.output = xfrm4_beet_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_BEET,
};
static int __init xfrm4_beet_init(void)
{
return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
}
static void __exit xfrm4_beet_exit(void)
{
int err;
err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
BUG_ON(err);
}
module_init(xfrm4_beet_init);
module_exit(xfrm4_beet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);
|
