2 * xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
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>
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>
20 /* Add encapsulation header.
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:
27 static int xfrm4_beet_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
29 struct ip_beet_phdr
*ph
;
30 struct iphdr
*iph
, *top_iph
;
36 optlen
= iph
->ihl
* 4 - sizeof(*iph
);
38 hdrlen
+= IPV4_BEET_PHMAXLEN
- (optlen
& 4);
40 skb_set_network_header(skb
, IPV4_BEET_PHMAXLEN
- x
->props
.header_len
-
42 skb
->mac_header
= skb
->network_header
+
43 offsetof(struct iphdr
, protocol
);
44 skb
->transport_header
= skb
->network_header
+ sizeof(*iph
);
46 ph
= (struct ip_beet_phdr
*)__skb_pull(skb
, sizeof(*iph
) - hdrlen
);
48 top_iph
= ip_hdr(skb
);
49 memmove(top_iph
, iph
, sizeof(*iph
));
50 if (unlikely(optlen
)) {
53 ph
->padlen
= 4 - (optlen
& 4);
54 ph
->hdrlen
= optlen
/ 8;
55 ph
->nexthdr
= top_iph
->protocol
;
57 memset(ph
+ 1, IPOPT_NOP
, ph
->padlen
);
59 top_iph
->protocol
= IPPROTO_BEETPH
;
60 top_iph
->ihl
= sizeof(struct iphdr
) / 4;
63 top_iph
->saddr
= x
->props
.saddr
.a4
;
64 top_iph
->daddr
= x
->id
.daddr
.a4
;
69 static int xfrm4_beet_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
71 struct iphdr
*iph
= ip_hdr(skb
);
77 if (unlikely(iph
->protocol
== IPPROTO_BEETPH
)) {
78 struct ip_beet_phdr
*ph
;
80 if (!pskb_may_pull(skb
, sizeof(*ph
)))
82 ph
= (struct ip_beet_phdr
*)(ipip_hdr(skb
) + 1);
84 phlen
= sizeof(*ph
) + ph
->padlen
;
85 optlen
= ph
->hdrlen
* 8 + (IPV4_BEET_PHMAXLEN
- phlen
);
86 if (optlen
< 0 || optlen
& 3 || optlen
> 250)
89 if (!pskb_may_pull(skb
, phlen
+ optlen
))
91 skb
->len
-= phlen
+ optlen
;
93 ph_nexthdr
= ph
->nexthdr
;
96 skb_set_network_header(skb
, phlen
- sizeof(*iph
));
97 memmove(skb_network_header(skb
), iph
, sizeof(*iph
));
98 skb_set_transport_header(skb
, phlen
+ optlen
);
99 skb
->data
= skb_transport_header(skb
);
102 iph
->ihl
= (sizeof(*iph
) + optlen
) / 4;
103 iph
->tot_len
= htons(skb
->len
+ iph
->ihl
* 4);
104 iph
->daddr
= x
->sel
.daddr
.a4
;
105 iph
->saddr
= x
->sel
.saddr
.a4
;
107 iph
->protocol
= ph_nexthdr
;
109 iph
->check
= ip_fast_csum(skb_network_header(skb
), iph
->ihl
);
115 static struct xfrm_mode xfrm4_beet_mode
= {
116 .input
= xfrm4_beet_input
,
117 .output
= xfrm4_beet_output
,
118 .owner
= THIS_MODULE
,
119 .encap
= XFRM_MODE_BEET
,
122 static int __init
xfrm4_beet_init(void)
124 return xfrm_register_mode(&xfrm4_beet_mode
, AF_INET
);
127 static void __exit
xfrm4_beet_exit(void)
131 err
= xfrm_unregister_mode(&xfrm4_beet_mode
, AF_INET
);
135 module_init(xfrm4_beet_init
);
136 module_exit(xfrm4_beet_exit
);
137 MODULE_LICENSE("GPL");
138 MODULE_ALIAS_XFRM_MODE(AF_INET
, XFRM_MODE_BEET
);