[net-next-2.6.git] / net / ipv6 / xfrm6_mode_transport.c

/*
 * xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
 *
 * Copyright (C) 2002 USAGI/WIDE Project
 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/stringify.h>
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/xfrm.h>

/* Add encapsulation header.
 *
 * The IP header and mutable extension headers will be moved forward to make
 * space for the encapsulation header.
 *
 * On exit, skb->h will be set to the start of the encapsulation header to be
 * filled in by x->type->output and skb->nh will be set to the nextheader field
 * of the extension header directly preceding the encapsulation header, or in
 * its absence, that of the top IP header.  The value of skb->data will always
 * point to the top IP header.
 */
static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
{
	struct ipv6hdr *iph;
	u8 *prevhdr;
	int hdr_len;

	skb_push(skb, x->props.header_len);
	iph = ipv6_hdr(skb);

	hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
	skb->nh.raw = prevhdr - x->props.header_len;
	skb->h.raw = skb->data + hdr_len;
	memmove(skb->data, iph, hdr_len);
	return 0;
}

/* Remove encapsulation header.
 *
 * The IP header will be moved over the top of the encapsulation header.
 *
 * On entry, skb->h shall point to where the IP header should be and skb->nh
 * shall be set to where the IP header currently is.  skb->data shall point
 * to the start of the payload.
 */
static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
{
	int ihl = skb->data - skb->h.raw;

	if (skb->h.raw != skb->nh.raw) {
		memmove(skb->h.raw, skb_network_header(skb), ihl);
		skb->nh.raw = skb->h.raw;
	}
	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
					   sizeof(struct ipv6hdr));
	skb->h.raw = skb->data;
	return 0;
}

static struct xfrm_mode xfrm6_transport_mode = {
	.input = xfrm6_transport_input,
	.output = xfrm6_transport_output,
	.owner = THIS_MODULE,
	.encap = XFRM_MODE_TRANSPORT,
};

static int __init xfrm6_transport_init(void)
{
	return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
}

static void __exit xfrm6_transport_exit(void)
{
	int err;

	err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
	BUG_ON(err);
}

module_init(xfrm6_transport_init);
module_exit(xfrm6_transport_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);
Commit	Line	Data
b59f45d0 HX	1	/*
	2	* xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
	3	*
	4	* Copyright (C) 2002 USAGI/WIDE Project
	5	* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
	6	*/
	7
	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>
	13	#include <net/dst.h>
	14	#include <net/ipv6.h>
	15	#include <net/xfrm.h>
	16
	17	/* Add encapsulation header.
	18	*
	19	* The IP header and mutable extension headers will be moved forward to make
	20	* space for the encapsulation header.
	21	*
	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 skb->nh will be set to the nextheader field
	24	* of the extension header directly preceding the encapsulation header, or in
	25	* its absence, that of the top IP header. The value of skb->data will always
	26	* point to the top IP header.
	27	*/
eb878e84	28	static int xfrm6_transport_output(struct xfrm_state x, struct sk_buff skb)
b59f45d0	29	{
b59f45d0 HX	30	struct ipv6hdr *iph;
	31	u8 *prevhdr;
	32	int hdr_len;
	33
	34	skb_push(skb, x->props.header_len);
0660e03f	35	iph = ipv6_hdr(skb);
b59f45d0	36
aee5adb4	37	hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
b59f45d0 HX	38	skb->nh.raw = prevhdr - x->props.header_len;
	39	skb->h.raw = skb->data + hdr_len;
	40	memmove(skb->data, iph, hdr_len);
	41	return 0;
	42	}
	43
31a4ab93 HX	44	/* Remove encapsulation header.
	45	*
	46	* The IP header will be moved over the top of the encapsulation header.
	47	*
	48	* On entry, skb->h shall point to where the IP header should be and skb->nh
	49	* shall be set to where the IP header currently is. skb->data shall point
	50	* to the start of the payload.
	51	*/
b59f45d0 HX	52	static int xfrm6_transport_input(struct xfrm_state x, struct sk_buff skb)
b59f45d0 HX	53	{
31a4ab93 HX	54	int ihl = skb->data - skb->h.raw;
31a4ab93 HX	55
d56f90a7 ACM	56	if (skb->h.raw != skb->nh.raw) {
	57	memmove(skb->h.raw, skb_network_header(skb), ihl);
	58	skb->nh.raw = skb->h.raw;
	59	}
0660e03f	60	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
31a4ab93 HX	61	sizeof(struct ipv6hdr));
31a4ab93 HX	62	skb->h.raw = skb->data;
b59f45d0 HX	63	return 0;
	64	}
	65
	66	static struct xfrm_mode xfrm6_transport_mode = {
	67	.input = xfrm6_transport_input,
	68	.output = xfrm6_transport_output,
	69	.owner = THIS_MODULE,
	70	.encap = XFRM_MODE_TRANSPORT,
	71	};
	72
	73	static int __init xfrm6_transport_init(void)
	74	{
	75	return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
	76	}
	77
	78	static void __exit xfrm6_transport_exit(void)
	79	{
	80	int err;
	81
	82	err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
	83	BUG_ON(err);
	84	}
	85
	86	module_init(xfrm6_transport_init);
	87	module_exit(xfrm6_transport_exit);
	88	MODULE_LICENSE("GPL");
	89	MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);