linux/net/ipv4/xfrm4_mode_beet.c
Joakim Koskela eb49e63093 ipsec: Interfamily IPSec BEET
Here's a revised version, based on Herbert's comments, of a fix for
the ipv6-inner, ipv4-outer interfamily ipsec beet mode. It fixes the
network header adjustment in interfamily, and doesn't reserve space
for the pseudo header anymore when we have ipv6 as the inner family.

Signed-off-by: Joakim Koskela <jookos@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-08-06 02:39:30 -07:00

159 lines
3.8 KiB
C

/*
* 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 = (struct ip_beet_phdr *)
__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 int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct iphdr *iph;
int optlen = 0;
int err = -EINVAL;
if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
struct ip_beet_phdr *ph;
int phlen;
if (!pskb_may_pull(skb, sizeof(*ph)))
goto out;
ph = (struct ip_beet_phdr *)skb->data;
phlen = sizeof(*ph) + ph->padlen;
optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
if (optlen < 0 || optlen & 3 || optlen > 250)
goto out;
XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;
if (!pskb_may_pull(skb, phlen))
goto out;
__skb_pull(skb, phlen);
}
skb_push(skb, sizeof(*iph));
skb_reset_network_header(skb);
memmove(skb->data - skb->mac_len, skb_mac_header(skb),
skb->mac_len);
skb_set_mac_header(skb, -skb->mac_len);
xfrm4_beet_make_header(skb);
iph = ip_hdr(skb);
iph->ihl += optlen / 4;
iph->tot_len = htons(skb->len);
iph->daddr = x->sel.daddr.a4;
iph->saddr = x->sel.saddr.a4;
iph->check = 0;
iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
err = 0;
out:
return err;
}
static struct xfrm_mode xfrm4_beet_mode = {
.input2 = xfrm4_beet_input,
.input = xfrm_prepare_input,
.output2 = xfrm4_beet_output,
.output = xfrm4_prepare_output,
.owner = THIS_MODULE,
.encap = XFRM_MODE_BEET,
.flags = XFRM_MODE_FLAG_TUNNEL,
};
static int __init xfrm4_beet_init(void)
{
return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
}
static void __exit xfrm4_beet_exit(void)
{
int err;
err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
BUG_ON(err);
}
module_init(xfrm4_beet_init);
module_exit(xfrm4_beet_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);