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 * 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.
30 static int xfrm4_beet_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
32 struct iphdr
*iph
, *top_iph
;
36 skb
->transport_header
= skb
->network_header
;
39 optlen
= iph
->ihl
* 4 - sizeof(*iph
);
41 hdrlen
+= IPV4_BEET_PHMAXLEN
- (optlen
& 4);
43 skb_set_network_header(skb
, IPV4_BEET_PHMAXLEN
- x
->props
.header_len
-
45 top_iph
= ip_hdr(skb
);
46 skb
->transport_header
+= sizeof(*iph
) - hdrlen
;
47 __skb_pull(skb
, sizeof(*iph
) - hdrlen
);
49 memmove(top_iph
, iph
, sizeof(*iph
));
50 if (unlikely(optlen
)) {
51 struct ip_beet_phdr
*ph
;
55 ph
= (struct ip_beet_phdr
*)skb_transport_header(skb
);
56 ph
->padlen
= 4 - (optlen
& 4);
57 ph
->hdrlen
= optlen
/ 8;
58 ph
->nexthdr
= top_iph
->protocol
;
60 memset(ph
+ 1, IPOPT_NOP
, ph
->padlen
);
62 top_iph
->protocol
= IPPROTO_BEETPH
;
63 top_iph
->ihl
= sizeof(struct iphdr
) / 4;
66 top_iph
->saddr
= x
->props
.saddr
.a4
;
67 top_iph
->daddr
= x
->id
.daddr
.a4
;
72 static int xfrm4_beet_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
74 struct iphdr
*iph
= ip_hdr(skb
);
80 if (unlikely(iph
->protocol
== IPPROTO_BEETPH
)) {
81 struct ip_beet_phdr
*ph
;
83 if (!pskb_may_pull(skb
, sizeof(*ph
)))
85 ph
= (struct ip_beet_phdr
*)(ipip_hdr(skb
) + 1);
87 phlen
= sizeof(*ph
) + ph
->padlen
;
88 optlen
= ph
->hdrlen
* 8 + (IPV4_BEET_PHMAXLEN
- phlen
);
89 if (optlen
< 0 || optlen
& 3 || optlen
> 250)
92 if (!pskb_may_pull(skb
, phlen
+ optlen
))
94 skb
->len
-= phlen
+ optlen
;
96 ph_nexthdr
= ph
->nexthdr
;
99 skb_set_network_header(skb
, phlen
- sizeof(*iph
));
100 memmove(skb_network_header(skb
), iph
, sizeof(*iph
));
101 skb_set_transport_header(skb
, phlen
+ optlen
);
102 skb
->data
= skb_transport_header(skb
);
105 iph
->ihl
= (sizeof(*iph
) + optlen
) / 4;
106 iph
->tot_len
= htons(skb
->len
+ iph
->ihl
* 4);
107 iph
->daddr
= x
->sel
.daddr
.a4
;
108 iph
->saddr
= x
->sel
.saddr
.a4
;
110 iph
->protocol
= ph_nexthdr
;
112 iph
->check
= ip_fast_csum(skb_network_header(skb
), iph
->ihl
);
118 static struct xfrm_mode xfrm4_beet_mode
= {
119 .input
= xfrm4_beet_input
,
120 .output
= xfrm4_beet_output
,
121 .owner
= THIS_MODULE
,
122 .encap
= XFRM_MODE_BEET
,
125 static int __init
xfrm4_beet_init(void)
127 return xfrm_register_mode(&xfrm4_beet_mode
, AF_INET
);
130 static void __exit
xfrm4_beet_exit(void)
134 err
= xfrm_unregister_mode(&xfrm4_beet_mode
, AF_INET
);
138 module_init(xfrm4_beet_init
);
139 module_exit(xfrm4_beet_exit
);
140 MODULE_LICENSE("GPL");
141 MODULE_ALIAS_XFRM_MODE(AF_INET
, XFRM_MODE_BEET
);