blob: b47030ba162bc97df715d11fc779f59df1db16e5 [file] [log] [blame]
Diego Beltrami0a694522006-10-03 23:47:05 -07001/*
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
Herbert Xu227620e2007-11-13 21:41:28 -080020static void xfrm4_beet_make_header(struct sk_buff *skb)
21{
22 struct iphdr *iph = ip_hdr(skb);
23
24 iph->ihl = 5;
25 iph->version = 4;
26
27 iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
28 iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
29
30 iph->id = XFRM_MODE_SKB_CB(skb)->id;
31 iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off;
32 iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl;
33}
34
Diego Beltrami0a694522006-10-03 23:47:05 -070035/* Add encapsulation header.
36 *
37 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
Diego Beltrami0a694522006-10-03 23:47:05 -070038 */
39static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
40{
Herbert Xu37fedd32007-10-10 15:44:44 -070041 struct ip_beet_phdr *ph;
Patrick McHardyea2f10a2007-04-05 16:04:04 -070042 struct iphdr *iph, *top_iph;
Diego Beltrami0a694522006-10-03 23:47:05 -070043 int hdrlen, optlen;
44
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -070045 iph = ip_hdr(skb);
Diego Beltrami0a694522006-10-03 23:47:05 -070046
47 hdrlen = 0;
48 optlen = iph->ihl * 4 - sizeof(*iph);
49 if (unlikely(optlen))
50 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
51
Herbert Xu7b277b12007-10-10 15:44:06 -070052 skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
53 hdrlen);
Herbert Xu37fedd32007-10-10 15:44:44 -070054 skb->mac_header = skb->network_header +
55 offsetof(struct iphdr, protocol);
56 skb->transport_header = skb->network_header + sizeof(*iph);
Diego Beltrami0a694522006-10-03 23:47:05 -070057
Herbert Xu227620e2007-11-13 21:41:28 -080058 xfrm4_beet_make_header(skb);
59
Herbert Xu37fedd32007-10-10 15:44:44 -070060 ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);
61
62 top_iph = ip_hdr(skb);
Herbert Xu36cf9ac2007-11-13 21:40:52 -080063
Diego Beltrami0a694522006-10-03 23:47:05 -070064 if (unlikely(optlen)) {
Diego Beltrami0a694522006-10-03 23:47:05 -070065 BUG_ON(optlen < 0);
66
Diego Beltrami0a694522006-10-03 23:47:05 -070067 ph->padlen = 4 - (optlen & 4);
Patrick McHardy05d22442007-04-23 22:39:02 -070068 ph->hdrlen = optlen / 8;
Diego Beltrami0a694522006-10-03 23:47:05 -070069 ph->nexthdr = top_iph->protocol;
Patrick McHardy04fef982007-04-05 15:54:39 -070070 if (ph->padlen)
71 memset(ph + 1, IPOPT_NOP, ph->padlen);
Diego Beltrami0a694522006-10-03 23:47:05 -070072
73 top_iph->protocol = IPPROTO_BEETPH;
74 top_iph->ihl = sizeof(struct iphdr) / 4;
75 }
76
77 top_iph->saddr = x->props.saddr.a4;
78 top_iph->daddr = x->id.daddr.a4;
79
80 return 0;
81}
82
83static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
84{
Herbert Xu227620e2007-11-13 21:41:28 -080085 struct iphdr *iph;
Diego Beltrami0a694522006-10-03 23:47:05 -070086 int optlen = 0;
Diego Beltrami0a694522006-10-03 23:47:05 -070087 int err = -EINVAL;
88
Herbert Xu227620e2007-11-13 21:41:28 -080089 if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
Patrick McHardy254d0d22007-04-05 16:03:33 -070090 struct ip_beet_phdr *ph;
Herbert Xu227620e2007-11-13 21:41:28 -080091 int phlen;
Diego Beltrami0a694522006-10-03 23:47:05 -070092
93 if (!pskb_may_pull(skb, sizeof(*ph)))
94 goto out;
Herbert Xu227620e2007-11-13 21:41:28 -080095
96 ph = (struct ip_beet_phdr *)skb->data;
Diego Beltrami0a694522006-10-03 23:47:05 -070097
Patrick McHardyd4b1e842007-04-05 15:59:41 -070098 phlen = sizeof(*ph) + ph->padlen;
Patrick McHardy05d22442007-04-23 22:39:02 -070099 optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
Diego Beltrami0a694522006-10-03 23:47:05 -0700100 if (optlen < 0 || optlen & 3 || optlen > 250)
101 goto out;
102
Herbert Xu227620e2007-11-13 21:41:28 -0800103 XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;
Diego Beltrami0a694522006-10-03 23:47:05 -0700104
Adrian Bunk322c8a32008-02-05 02:51:39 -0800105 if (!pskb_may_pull(skb, phlen))
Herbert Xu227620e2007-11-13 21:41:28 -0800106 goto out;
107 __skb_pull(skb, phlen);
Diego Beltrami0a694522006-10-03 23:47:05 -0700108 }
109
Herbert Xu227620e2007-11-13 21:41:28 -0800110 skb_push(skb, sizeof(*iph));
111 skb_reset_network_header(skb);
112
113 memmove(skb->data - skb->mac_len, skb_mac_header(skb),
114 skb->mac_len);
115 skb_set_mac_header(skb, -skb->mac_len);
116
117 xfrm4_beet_make_header(skb);
Diego Beltrami0a694522006-10-03 23:47:05 -0700118
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700119 iph = ip_hdr(skb);
Herbert Xu227620e2007-11-13 21:41:28 -0800120
121 iph->ihl += optlen / 4;
122 iph->tot_len = htons(skb->len);
Diego Beltrami0a694522006-10-03 23:47:05 -0700123 iph->daddr = x->sel.daddr.a4;
124 iph->saddr = x->sel.saddr.a4;
Diego Beltrami0a694522006-10-03 23:47:05 -0700125 iph->check = 0;
Arnaldo Carvalho de Melod56f90a2007-04-10 20:50:43 -0700126 iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
Diego Beltrami0a694522006-10-03 23:47:05 -0700127 err = 0;
128out:
129 return err;
130}
131
132static struct xfrm_mode xfrm4_beet_mode = {
Herbert Xu227620e2007-11-13 21:41:28 -0800133 .input2 = xfrm4_beet_input,
134 .input = xfrm_prepare_input,
Herbert Xu36cf9ac2007-11-13 21:40:52 -0800135 .output2 = xfrm4_beet_output,
136 .output = xfrm4_prepare_output,
Diego Beltrami0a694522006-10-03 23:47:05 -0700137 .owner = THIS_MODULE,
138 .encap = XFRM_MODE_BEET,
Herbert Xu1bfcb102007-10-17 21:31:50 -0700139 .flags = XFRM_MODE_FLAG_TUNNEL,
Diego Beltrami0a694522006-10-03 23:47:05 -0700140};
141
142static int __init xfrm4_beet_init(void)
143{
144 return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
145}
146
147static void __exit xfrm4_beet_exit(void)
148{
149 int err;
150
151 err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
152 BUG_ON(err);
153}
154
155module_init(xfrm4_beet_init);
156module_exit(xfrm4_beet_exit);
157MODULE_LICENSE("GPL");
158MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);