81 lines
2.1 KiB
C
81 lines
2.1 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.
|
||
|
|
*/
|
||
|
|
static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
|
||
|
|
{
|
||
|
|
struct iphdr *iph = ip_hdr(skb);
|
||
|
|
int ihl = iph->ihl * 4;
|
||
|
|
|
||
|
|
skb_set_network_header(skb, -x->props.header_len);
|
||
|
|
skb->mac_header = skb->network_header +
|
||
|
|
offsetof(struct iphdr, protocol);
|
||
|
|
skb->transport_header = skb->network_header + ihl;
|
||
|
|
__skb_pull(skb, ihl);
|
||
|
|
memmove(skb_network_header(skb), 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_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;
|
||
|
|
}
|
||
|
|
ip_hdr(skb)->tot_len = htons(skb->len + ihl);
|
||
|
|
skb_reset_transport_header(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);
|