[linux-2.6-block.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_set_network_header(skb,
			       (prevhdr - x->props.header_len) - skb->data);
	skb_set_transport_header(skb, 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_transport_header(skb);

	if (skb->transport_header != skb->network_header) {
		memmove(skb_transport_header(skb),
			skb_network_header(skb), ihl);
		skb->network_header = skb->transport_header;
	}
	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
					   sizeof(struct ipv6hdr));
	skb_reset_transport_header(skb);
	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);
ddc7b8e3 ACM	38	skb_set_network_header(skb,
ddc7b8e3 ACM	39	(prevhdr - x->props.header_len) - skb->data);
967b05f6	40	skb_set_transport_header(skb, hdr_len);
b59f45d0 HX	41	memmove(skb->data, iph, hdr_len);
	42	return 0;
	43	}
	44
31a4ab93 HX	45	/* Remove encapsulation header.
	46	*
	47	* The IP header will be moved over the top of the encapsulation header.
	48	*
	49	* On entry, skb->h shall point to where the IP header should be and skb->nh
	50	* shall be set to where the IP header currently is. skb->data shall point
	51	* to the start of the payload.
	52	*/
b59f45d0 HX	53	static int xfrm6_transport_input(struct xfrm_state x, struct sk_buff skb)
b59f45d0 HX	54	{
9c70220b	55	int ihl = skb->data - skb_transport_header(skb);
31a4ab93	56
b0e380b1	57	if (skb->transport_header != skb->network_header) {
9c70220b ACM	58	memmove(skb_transport_header(skb),
9c70220b ACM	59	skb_network_header(skb), ihl);
b0e380b1	60	skb->network_header = skb->transport_header;
d56f90a7	61	}
0660e03f	62	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
31a4ab93	63	sizeof(struct ipv6hdr));
badff6d0	64	skb_reset_transport_header(skb);
b59f45d0 HX	65	return 0;
	66	}
	67
	68	static struct xfrm_mode xfrm6_transport_mode = {
	69	.input = xfrm6_transport_input,
	70	.output = xfrm6_transport_output,
	71	.owner = THIS_MODULE,
	72	.encap = XFRM_MODE_TRANSPORT,
	73	};
	74
	75	static int __init xfrm6_transport_init(void)
	76	{
	77	return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
	78	}
	79
	80	static void __exit xfrm6_transport_exit(void)
	81	{
	82	int err;
	83
	84	err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
	85	BUG_ON(err);
	86	}
	87
	88	module_init(xfrm6_transport_init);
	89	module_exit(xfrm6_transport_exit);
	90	MODULE_LICENSE("GPL");
	91	MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);