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/*
* xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
*
* Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
* Miika Komu <miika@iki.fi>
* Herbert Xu <herbert@gondor.apana.org.au>
* Abhinav Pathak <abhinav.pathak@hiit.fi>
* Jeff Ahrenholz <ahrenholz@gmail.com>
*/
#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>
static void xfrm4_beet_make_header(struct sk_buff *skb)
{
struct iphdr *iph = ip_hdr(skb);
iph->ihl = 5;
iph->version = 4;
iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
iph->id = XFRM_MODE_SKB_CB(skb)->id;
iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off;
iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl;
}
/* Add encapsulation header.
*
* The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
*/
static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_beet_phdr *ph;
struct iphdr *top_iph;
int hdrlen, optlen;
hdrlen = 0;
optlen = XFRM_MODE_SKB_CB(skb)->optlen;
if (unlikely(optlen))
hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
skb_set_network_header(skb, -x->props.header_len -
hdrlen + (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
if (x->sel.family != AF_INET6)
skb->network_header += IPV4_BEET_PHMAXLEN;
skb->mac_header = skb->network_header +
offsetof(struct iphdr, protocol);
skb->transport_header = skb->network_header + sizeof(*top_iph);
xfrm4_beet_make_header(skb);
ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
top_iph = ip_hdr(skb);
if (unlikely(optlen)) {
BUG_ON(optlen < 0);
ph->padlen = 4 - (optlen & 4);
ph->hdrlen = optlen / 8;
ph->nexthdr = top_iph->protocol;
if (ph->padlen)
memset(ph + 1, IPOPT_NOP, ph->padlen);
top_iph->protocol = IPPROTO_BEETPH;
top_iph->ihl = sizeof(struct iphdr) / 4;
}
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
return 0;
}
static struct xfrm_mode xfrm4_beet_mode = {
.output2 = xfrm4_beet_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_BEET,
.flags = XFRM_MODE_FLAG_TUNNEL,
.family = AF_INET,
};
static int __init xfrm4_beet_init(void)
{
return xfrm_register_mode(&xfrm4_beet_mode);
}
static void __exit xfrm4_beet_exit(void)
{
xfrm_unregister_mode(&xfrm4_beet_mode);
}
module_init(xfrm4_beet_init);
module_exit(xfrm4_beet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);
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