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/*
* xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
*
* 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/dsfield.h>
#include <net/dst.h>
#include <net/inet_ecn.h>
#include <net/ipv6.h>
#include <net/xfrm.h>
static void xfrm6_beet_make_header(struct sk_buff *skb)
{
struct ipv6hdr *iph = ipv6_hdr(skb);
iph->version = 6;
memcpy(iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
sizeof(iph->flow_lbl));
iph->nexthdr = XFRM_MODE_SKB_CB(skb)->protocol;
ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
iph->hop_limit = 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 xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *top_iph;
struct ip_beet_phdr *ph;
int optlen, hdr_len;
hdr_len = 0;
optlen = XFRM_MODE_SKB_CB(skb)->optlen;
if (unlikely(optlen))
hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
skb_set_network_header(skb, -x->props.header_len - hdr_len);
if (x->sel.family != AF_INET6)
skb->network_header += IPV4_BEET_PHMAXLEN;
skb->mac_header = skb->network_header +
offsetof(struct ipv6hdr, nexthdr);
skb->transport_header = skb->network_header + sizeof(*top_iph);
ph = (struct ip_beet_phdr *)__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl-hdr_len);
xfrm6_beet_make_header(skb);
top_iph = ipv6_hdr(skb);
if (unlikely(optlen)) {
BUG_ON(optlen < 0);
ph->padlen = 4 - (optlen & 4);
ph->hdrlen = optlen / 8;
ph->nexthdr = top_iph->nexthdr;
if (ph->padlen)
memset(ph + 1, IPOPT_NOP, ph->padlen);
top_iph->nexthdr = IPPROTO_BEETPH;
}
top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
return 0;
}
static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *ip6h;
const unsigned char *old_mac;
int size = sizeof(struct ipv6hdr);
int err;
err = skb_cow_head(skb, size + skb->mac_len);
if (err)
goto out;
__skb_push(skb, size);
skb_reset_network_header(skb);
old_mac = skb_mac_header(skb);
skb_set_mac_header(skb, -skb->mac_len);
memmove(skb_mac_header(skb), old_mac, skb->mac_len);
xfrm6_beet_make_header(skb);
ip6h = ipv6_hdr(skb);
ip6h->payload_len = htons(skb->len - size);
ip6h->daddr = *(struct in6_addr *)&x->sel.daddr.a6;
ip6h->saddr = *(struct in6_addr *)&x->sel.saddr.a6;
err = 0;
out:
return err;
}
static struct xfrm_mode xfrm6_beet_mode = {
.input2 = xfrm6_beet_input,
.input = xfrm_prepare_input,
.output2 = xfrm6_beet_output,
.output = xfrm6_prepare_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_BEET,
.flags = XFRM_MODE_FLAG_TUNNEL,
};
static int __init xfrm6_beet_init(void)
{
return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
}
static void __exit xfrm6_beet_exit(void)
{
int err;
err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
BUG_ON(err);
}
module_init(xfrm6_beet_init);
module_exit(xfrm6_beet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);
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