1 /*
2 * xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
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/dsfield.h>
17 #include <net/dst.h>
18 #include <net/inet_ecn.h>
19 #include <net/ipv6.h>
20 #include <net/xfrm.h>
21
22 static void xfrm6_beet_make_header(struct sk_buff *skb)
23 {
24 struct ipv6hdr *iph = ipv6_hdr(skb);
25
26 iph->version = 6;
27
28 memcpy(iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
29 sizeof(iph->flow_lbl));
30 iph->nexthdr = XFRM_MODE_SKB_CB(skb)->protocol;
31
32 ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
33 iph->hop_limit = XFRM_MODE_SKB_CB(skb)->ttl;
34 }
35
36 /* Add encapsulation header.
37 *
38 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
39 */
40 static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
41 {
42 struct ipv6hdr *top_iph;
43 struct ip_beet_phdr *ph;
44 int optlen, hdr_len;
45
46 hdr_len = 0;
47 optlen = XFRM_MODE_SKB_CB(skb)->optlen;
48 if (unlikely(optlen))
49 hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
50
51 skb_set_network_header(skb, -x->props.header_len - hdr_len);
52 if (x->sel.family != AF_INET6)
53 skb->network_header += IPV4_BEET_PHMAXLEN;
54 skb->mac_header = skb->network_header +
55 offsetof(struct ipv6hdr, nexthdr);
56 skb->transport_header = skb->network_header + sizeof(*top_iph);
57 ph = (struct ip_beet_phdr *)__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl-hdr_len);
58
59 xfrm6_beet_make_header(skb);
60
61 top_iph = ipv6_hdr(skb);
62 if (unlikely(optlen)) {
63
64 BUG_ON(optlen < 0);
65
66 ph->padlen = 4 - (optlen & 4);
67 ph->hdrlen = optlen / 8;
68 ph->nexthdr = top_iph->nexthdr;
69 if (ph->padlen)
70 memset(ph + 1, IPOPT_NOP, ph->padlen);
71
72 top_iph->nexthdr = IPPROTO_BEETPH;
73 }
74
75 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
76 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
77 return 0;
78 }
79
80 static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
81 {
82 struct ipv6hdr *ip6h;
83 int size = sizeof(struct ipv6hdr);
84 int err;
85
86 err = skb_cow_head(skb, size + skb->mac_len);
87 if (err)
88 goto out;
89
90 __skb_push(skb, size);
91 skb_reset_network_header(skb);
92 skb_mac_header_rebuild(skb);
93
94 xfrm6_beet_make_header(skb);
95
96 ip6h = ipv6_hdr(skb);
97 ip6h->payload_len = htons(skb->len - size);
98 ip6h->daddr = *(struct in6_addr *)&x->sel.daddr.a6;
99 ip6h->saddr = *(struct in6_addr *)&x->sel.saddr.a6;
100 err = 0;
101 out:
102 return err;
103 }
104
105 static struct xfrm_mode xfrm6_beet_mode = {
106 .input2 = xfrm6_beet_input,
107 .input = xfrm_prepare_input,
108 .output2 = xfrm6_beet_output,
109 .output = xfrm6_prepare_output,
110 .owner = THIS_MODULE,
111 .encap = XFRM_MODE_BEET,
112 .flags = XFRM_MODE_FLAG_TUNNEL,
113 };
114
115 static int __init xfrm6_beet_init(void)
116 {
117 return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
118 }
119
120 static void __exit xfrm6_beet_exit(void)
121 {
122 int err;
123
124 err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
125 BUG_ON(err);
126 }
127
128 module_init(xfrm6_beet_init);
129 module_exit(xfrm6_beet_exit);
130 MODULE_LICENSE("GPL");
131 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);
132
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