2 * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
4 * Copyright (C) 2002 USAGI/WIDE Project
5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
12 #include <linux/stringify.h>
17 /* Add encapsulation header.
19 * The IP header and mutable extension headers will be moved forward to make
20 * space for the encapsulation header.
22 * On exit, skb->h will be set to the start of the encapsulation header to be
23 * filled in by x->type->output and the mac header will be set to the
24 * nextheader field of the extension header directly preceding the
25 * encapsulation header, or in its absence, that of the top IP header.
26 * The value of skb->data and the network header will always point to the
29 static int xfrm6_transport_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
35 skb_push(skb
, x
->props
.header_len
);
38 hdr_len
= x
->type
->hdr_offset(x
, skb
, &prevhdr
);
39 skb_set_mac_header(skb
, (prevhdr
- x
->props
.header_len
) - skb
->data
);
40 skb_reset_network_header(skb
);
41 skb_set_transport_header(skb
, hdr_len
);
42 memmove(skb
->data
, iph
, hdr_len
);
46 /* Remove encapsulation header.
48 * The IP header will be moved over the top of the encapsulation header.
50 * On entry, skb->h shall point to where the IP header should be and skb->nh
51 * shall be set to where the IP header currently is. skb->data shall point
52 * to the start of the payload.
54 static int xfrm6_transport_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
56 int ihl
= skb
->data
- skb_transport_header(skb
);
58 if (skb
->transport_header
!= skb
->network_header
) {
59 memmove(skb_transport_header(skb
),
60 skb_network_header(skb
), ihl
);
61 skb
->network_header
= skb
->transport_header
;
63 ipv6_hdr(skb
)->payload_len
= htons(skb
->len
+ ihl
-
64 sizeof(struct ipv6hdr
));
65 skb_reset_transport_header(skb
);
69 static struct xfrm_mode xfrm6_transport_mode
= {
70 .input
= xfrm6_transport_input
,
71 .output
= xfrm6_transport_output
,
73 .encap
= XFRM_MODE_TRANSPORT
,
76 static int __init
xfrm6_transport_init(void)
78 return xfrm_register_mode(&xfrm6_transport_mode
, AF_INET6
);
81 static void __exit
xfrm6_transport_exit(void)
85 err
= xfrm_unregister_mode(&xfrm6_transport_mode
, AF_INET6
);
89 module_init(xfrm6_transport_init
);
90 module_exit(xfrm6_transport_exit
);
91 MODULE_LICENSE("GPL");
92 MODULE_ALIAS_XFRM_MODE(AF_INET6
, XFRM_MODE_TRANSPORT
);