82 строки
2.0 KiB
C
82 строки
2.0 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 xfrm_state *x, struct sk_buff *skb)
|
|
{
|
|
struct iphdr *iph;
|
|
int ihl;
|
|
|
|
iph = skb->nh.iph;
|
|
skb->h.ipiph = iph;
|
|
|
|
ihl = iph->ihl * 4;
|
|
skb->h.raw += ihl;
|
|
|
|
skb->nh.raw = memmove(skb_push(skb, x->props.header_len), iph, ihl);
|
|
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 xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
|
|
{
|
|
int ihl = skb->data - skb->h.raw;
|
|
|
|
if (skb->h.raw != skb->nh.raw)
|
|
skb->nh.raw = memmove(skb->h.raw, skb->nh.raw, ihl);
|
|
skb->nh.iph->tot_len = htons(skb->len + ihl);
|
|
skb->h.raw = skb->data;
|
|
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);
|