Commit | Line | Data |
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0a69452c DB |
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 | */ | |
30 | static 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; | |
c5027c9a | 45 | skb->h.raw += sizeof(*iph) - hdrlen; |
0a69452c | 46 | |
c5027c9a | 47 | memmove(top_iph, iph, sizeof(*iph)); |
0a69452c DB |
48 | if (unlikely(optlen)) { |
49 | struct ip_beet_phdr *ph; | |
50 | ||
51 | BUG_ON(optlen < 0); | |
52 | ||
53 | ph = (struct ip_beet_phdr *)skb->h.raw; | |
54 | ph->padlen = 4 - (optlen & 4); | |
55 | ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8; | |
56 | ph->nexthdr = top_iph->protocol; | |
04fef989 PM |
57 | if (ph->padlen) |
58 | memset(ph + 1, IPOPT_NOP, ph->padlen); | |
0a69452c DB |
59 | |
60 | top_iph->protocol = IPPROTO_BEETPH; | |
61 | top_iph->ihl = sizeof(struct iphdr) / 4; | |
62 | } | |
63 | ||
64 | top_iph->saddr = x->props.saddr.a4; | |
65 | top_iph->daddr = x->id.daddr.a4; | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
70 | static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb) | |
71 | { | |
72 | struct iphdr *iph = skb->nh.iph; | |
73 | int phlen = 0; | |
74 | int optlen = 0; | |
75 | __u8 ph_nexthdr = 0, protocol = 0; | |
76 | int err = -EINVAL; | |
77 | ||
78 | protocol = iph->protocol; | |
79 | ||
80 | if (unlikely(iph->protocol == IPPROTO_BEETPH)) { | |
254d0d24 | 81 | struct ip_beet_phdr *ph; |
0a69452c DB |
82 | |
83 | if (!pskb_may_pull(skb, sizeof(*ph))) | |
84 | goto out; | |
254d0d24 | 85 | ph = (struct ip_beet_phdr *)(skb->h.ipiph + 1); |
0a69452c | 86 | |
d4b1e840 PM |
87 | phlen = sizeof(*ph) + ph->padlen; |
88 | optlen = ph->hdrlen * 8 - phlen; | |
0a69452c DB |
89 | if (optlen < 0 || optlen & 3 || optlen > 250) |
90 | goto out; | |
91 | ||
d4b1e840 | 92 | if (!pskb_may_pull(skb, phlen + optlen)) |
0a69452c | 93 | goto out; |
254d0d24 | 94 | skb->len -= phlen + optlen; |
0a69452c DB |
95 | |
96 | ph_nexthdr = ph->nexthdr; | |
97 | } | |
98 | ||
d4b1e840 PM |
99 | skb->nh.raw = skb->data + (phlen - sizeof(*iph)); |
100 | memmove(skb->nh.raw, iph, sizeof(*iph)); | |
101 | skb->h.raw = skb->data + (phlen + optlen); | |
254d0d24 | 102 | skb->data = skb->h.raw; |
0a69452c DB |
103 | |
104 | iph = skb->nh.iph; | |
105 | iph->ihl = (sizeof(*iph) + optlen) / 4; | |
d4b1e840 | 106 | iph->tot_len = htons(skb->len + iph->ihl * 4); |
0a69452c DB |
107 | iph->daddr = x->sel.daddr.a4; |
108 | iph->saddr = x->sel.saddr.a4; | |
109 | if (ph_nexthdr) | |
110 | iph->protocol = ph_nexthdr; | |
111 | else | |
112 | iph->protocol = protocol; | |
113 | iph->check = 0; | |
114 | iph->check = ip_fast_csum(skb->nh.raw, iph->ihl); | |
115 | err = 0; | |
116 | out: | |
117 | return err; | |
118 | } | |
119 | ||
120 | static struct xfrm_mode xfrm4_beet_mode = { | |
121 | .input = xfrm4_beet_input, | |
122 | .output = xfrm4_beet_output, | |
123 | .owner = THIS_MODULE, | |
124 | .encap = XFRM_MODE_BEET, | |
125 | }; | |
126 | ||
127 | static int __init xfrm4_beet_init(void) | |
128 | { | |
129 | return xfrm_register_mode(&xfrm4_beet_mode, AF_INET); | |
130 | } | |
131 | ||
132 | static void __exit xfrm4_beet_exit(void) | |
133 | { | |
134 | int err; | |
135 | ||
136 | err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET); | |
137 | BUG_ON(err); | |
138 | } | |
139 | ||
140 | module_init(xfrm4_beet_init); | |
141 | module_exit(xfrm4_beet_exit); | |
142 | MODULE_LICENSE("GPL"); | |
143 | MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET); |