tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
3 *
4 * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
5 * Miika Komu <miika@iki.fi>
6 * Herbert Xu <herbert@gondor.apana.org.au>
7 * Abhinav Pathak <abhinav.pathak@hiit.fi>
8 * Jeff Ahrenholz <ahrenholz@gmail.com>
9 */
10
11#include <linux/init.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/skbuff.h>
15#include <linux/stringify.h>
16#include <net/dst.h>
17#include <net/ip.h>
18#include <net/xfrm.h>
19
20/* Add encapsulation header.
21 *
22 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
23 * The following fields in it shall be filled in by x->type->output:
24 * tot_len
25 * check
26 *
27 * On exit, skb->h will be set to the start of the payload to be processed
28 * by x->type->output and skb->nh will be set to the top IP header.
29 */
30static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
31{
32 struct iphdr *iph, *top_iph = NULL;
33 int hdrlen, optlen;
34
35 iph = skb->nh.iph;
36 skb->h.ipiph = iph;
37
38 hdrlen = 0;
39 optlen = iph->ihl * 4 - sizeof(*iph);
40 if (unlikely(optlen))
41 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
42
43 skb->nh.raw = skb_push(skb, x->props.header_len + hdrlen);
44 top_iph = skb->nh.iph;
45 hdrlen = iph->ihl * 4 - optlen;
46 skb->h.raw += hdrlen;
47
48 memmove(top_iph, iph, hdrlen);
49 if (unlikely(optlen)) {
50 struct ip_beet_phdr *ph;
51
52 BUG_ON(optlen < 0);
53
54 ph = (struct ip_beet_phdr *)skb->h.raw;
55 ph->padlen = 4 - (optlen & 4);
56 ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8;
57 ph->nexthdr = top_iph->protocol;
58
59 top_iph->protocol = IPPROTO_BEETPH;
60 top_iph->ihl = sizeof(struct iphdr) / 4;
61 }
62
63 top_iph->saddr = x->props.saddr.a4;
64 top_iph->daddr = x->id.daddr.a4;
65
66 return 0;
67}
68
69static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
70{
71 struct iphdr *iph = skb->nh.iph;
72 int phlen = 0;
73 int optlen = 0;
74 __u8 ph_nexthdr = 0, protocol = 0;
75 int err = -EINVAL;
76
77 protocol = iph->protocol;
78
79 if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
80 struct ip_beet_phdr *ph = (struct ip_beet_phdr*)(iph + 1);
81
82 if (!pskb_may_pull(skb, sizeof(*ph)))
83 goto out;
84
85 phlen = ph->hdrlen * 8;
86 optlen = phlen - ph->padlen - sizeof(*ph);
87 if (optlen < 0 || optlen & 3 || optlen > 250)
88 goto out;
89
90 if (!pskb_may_pull(skb, phlen))
91 goto out;
92
93 ph_nexthdr = ph->nexthdr;
94 }
95
96 skb_push(skb, sizeof(*iph) - phlen + optlen);
97 memmove(skb->data, skb->nh.raw, sizeof(*iph));
98 skb->nh.raw = skb->data;
99
100 iph = skb->nh.iph;
101 iph->ihl = (sizeof(*iph) + optlen) / 4;
102 iph->tot_len = htons(skb->len);
103 iph->daddr = x->sel.daddr.a4;
104 iph->saddr = x->sel.saddr.a4;
105 if (ph_nexthdr)
106 iph->protocol = ph_nexthdr;
107 else
108 iph->protocol = protocol;
109 iph->check = 0;
110 iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
111 err = 0;
112out:
113 return err;
114}
115
116static struct xfrm_mode xfrm4_beet_mode = {
117 .input = xfrm4_beet_input,
118 .output = xfrm4_beet_output,
119 .owner = THIS_MODULE,
120 .encap = XFRM_MODE_BEET,
121};
122
123static int __init xfrm4_beet_init(void)
124{
125 return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
126}
127
128static void __exit xfrm4_beet_exit(void)
129{
130 int err;
131
132 err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
133 BUG_ON(err);
134}
135
136module_init(xfrm4_beet_init);
137module_exit(xfrm4_beet_exit);
138MODULE_LICENSE("GPL");
139MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);