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 */
24static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
25{
26 struct ip_beet_phdr *ph;
27 struct iphdr *iph, *top_iph;
28 int hdrlen, optlen;
29
30 iph = ip_hdr(skb);
31
32 hdrlen = 0;
33 optlen = iph->ihl * 4 - sizeof(*iph);
34 if (unlikely(optlen))
35 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
36
37 skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
38 hdrlen);
39 skb->mac_header = skb->network_header +
40 offsetof(struct iphdr, protocol);
41 skb->transport_header = skb->network_header + sizeof(*iph);
42
43 ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);
44
45 top_iph = ip_hdr(skb);
46 memmove(top_iph, iph, sizeof(*iph));
47 if (unlikely(optlen)) {
48 BUG_ON(optlen < 0);
49
50 ph->padlen = 4 - (optlen & 4);
51 ph->hdrlen = optlen / 8;
52 ph->nexthdr = top_iph->protocol;
53 if (ph->padlen)
54 memset(ph + 1, IPOPT_NOP, ph->padlen);
55
56 top_iph->protocol = IPPROTO_BEETPH;
57 top_iph->ihl = sizeof(struct iphdr) / 4;
58 }
59
60 top_iph->saddr = x->props.saddr.a4;
61 top_iph->daddr = x->id.daddr.a4;
62
63 return 0;
64}
65
66static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
67{
68 struct iphdr *iph = ip_hdr(skb);
69 int phlen = 0;
70 int optlen = 0;
71 u8 ph_nexthdr = 0;
72 int err = -EINVAL;
73
74 if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
75 struct ip_beet_phdr *ph;
76
77 if (!pskb_may_pull(skb, sizeof(*ph)))
78 goto out;
79 ph = (struct ip_beet_phdr *)(ipip_hdr(skb) + 1);
80
81 phlen = sizeof(*ph) + ph->padlen;
82 optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
83 if (optlen < 0 || optlen & 3 || optlen > 250)
84 goto out;
85
86 if (!pskb_may_pull(skb, phlen + optlen))
87 goto out;
88 skb->len -= phlen + optlen;
89
90 ph_nexthdr = ph->nexthdr;
91 }
92
93 skb_set_network_header(skb, phlen - sizeof(*iph));
94 memmove(skb_network_header(skb), iph, sizeof(*iph));
95 skb_set_transport_header(skb, phlen + optlen);
96 skb->data = skb_transport_header(skb);
97
98 iph = ip_hdr(skb);
99 iph->ihl = (sizeof(*iph) + optlen) / 4;
100 iph->tot_len = htons(skb->len + iph->ihl * 4);
101 iph->daddr = x->sel.daddr.a4;
102 iph->saddr = x->sel.saddr.a4;
103 if (ph_nexthdr)
104 iph->protocol = ph_nexthdr;
105 iph->check = 0;
106 iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
107 err = 0;
108out:
109 return err;
110}
111
112static struct xfrm_mode xfrm4_beet_mode = {
113 .input = xfrm4_beet_input,
114 .output = xfrm4_beet_output,
115 .owner = THIS_MODULE,
116 .encap = XFRM_MODE_BEET,
117 .flags = XFRM_MODE_FLAG_TUNNEL,
118};
119
120static int __init xfrm4_beet_init(void)
121{
122 return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
123}
124
125static void __exit xfrm4_beet_exit(void)
126{
127 int err;
128
129 err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
130 BUG_ON(err);
131}
132
133module_init(xfrm4_beet_init);
134module_exit(xfrm4_beet_exit);
135MODULE_LICENSE("GPL");
136MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);