linux/net/ipv4/xfrm4_mode_transport.c
Herbert Xu b59f45d0b2 [IPSEC] xfrm: Abstract out encapsulation modes
This patch adds the structure xfrm_mode.  It is meant to represent
the operations carried out by transport/tunnel modes.

By doing this we allow additional encapsulation modes to be added
without clogging up the xfrm_input/xfrm_output paths.

Candidate modes include 4-to-6 tunnel mode, 6-to-4 tunnel mode, and
BEET modes.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17 21:28:39 -07:00

70 lines
1.5 KiB
C

/*
* xfrm4_mode_transport.c - Transport mode encapsulation for IPv4.
*
* 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/ip.h>
#include <net/xfrm.h>
/* Add encapsulation header.
*
* The IP header will be moved forward to make space for the encapsulation
* header.
*
* On exit, skb->h will be set to the start of the payload to be processed
* by x->type->output and skb->nh will be set to the top IP header.
*/
static int xfrm4_transport_output(struct sk_buff *skb)
{
struct xfrm_state *x;
struct iphdr *iph;
int ihl;
iph = skb->nh.iph;
skb->h.ipiph = iph;
ihl = iph->ihl * 4;
skb->h.raw += ihl;
x = skb->dst->xfrm;
skb->nh.raw = memmove(skb_push(skb, x->props.header_len), iph, ihl);
return 0;
}
static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
{
return 0;
}
static struct xfrm_mode xfrm4_transport_mode = {
.input = xfrm4_transport_input,
.output = xfrm4_transport_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_TRANSPORT,
};
static int __init xfrm4_transport_init(void)
{
return xfrm_register_mode(&xfrm4_transport_mode, AF_INET);
}
static void __exit xfrm4_transport_exit(void)
{
int err;
err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET);
BUG_ON(err);
}
module_init(xfrm4_transport_init);
module_exit(xfrm4_transport_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT);