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linux-next/net/ipv4/xfrm4_mode_beet.c
Herbert Xu 227620e295 [IPSEC]: Separate inner/outer mode processing on input
With inter-family transforms the inner mode differs from the outer
mode.  Attempting to handle both sides from the same function means
that it needs to handle both IPv4 and IPv6 which creates duplication
and confusion.

This patch separates the two parts on the input path so that each
function deals with one family only.

In particular, the functions xfrm4_extract_inut/xfrm6_extract_inut
moves the pertinent fields from the IPv4/IPv6 IP headers into a
neutral format stored in skb->cb.  This is then used by the inner mode
input functions to modify the inner IP header.  In this way the input
function no longer has to know about the outer address family.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:53:46 -08:00

159 lines
3.7 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 *iph, *top_iph;
int hdrlen, optlen;
iph = ip_hdr(skb);
hdrlen = 0;
optlen = iph->ihl * 4 - sizeof(*iph);
if (unlikely(optlen))
hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
hdrlen);
skb->mac_header = skb->network_header +
offsetof(struct iphdr, protocol);
skb->transport_header = skb->network_header + sizeof(*iph);
xfrm4_beet_make_header(skb);
ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - 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);