Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/cpufreq
[linux-2.6] / net / ipv4 / xfrm4_mode_beet.c
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  */
24 static 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
66 static 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;
108 out:
109         return err;
110 }
111
112 static 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
120 static int __init xfrm4_beet_init(void)
121 {
122         return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
123 }
124
125 static 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
133 module_init(xfrm4_beet_init);
134 module_exit(xfrm4_beet_exit);
135 MODULE_LICENSE("GPL");
136 MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);