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linux-next/net/ipv4/xfrm4_mode_beet.c
Herbert Xu 36cf9acf93 [IPSEC]: Separate inner/outer mode processing on output
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 output path so that each
function deals with one family only.

In particular, the functions xfrm4_extract_output/xfrm6_extract_output
moves the pertinent fields from the IPv4/IPv6 IP headers into a
neutral format stored in skb->cb.  This is then used by the outer mode
output functions to write the outer IP header.  In this way the output
function no longer has to know about the inner address family.

Since the extract functions are only called by tunnel modes (the only
modes that can support inter-family transforms), I've also moved the
xfrm*_tunnel_check_size calls into them.  This allows the correct ICMP
message to be sent as opposed to now where you might call icmp_send
with an IPv6 packet and vice versa.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:53:45 -08:00

148 lines
3.6 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>
/* 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);
ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);
top_iph = ip_hdr(skb);
top_iph->ihl = 5;
top_iph->version = 4;
top_iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
top_iph->id = XFRM_MODE_SKB_CB(skb)->id;
top_iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off;
top_iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl;
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 = ip_hdr(skb);
int phlen = 0;
int optlen = 0;
u8 ph_nexthdr = 0;
int err = -EINVAL;
if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
struct ip_beet_phdr *ph;
if (!pskb_may_pull(skb, sizeof(*ph)))
goto out;
ph = (struct ip_beet_phdr *)(ipip_hdr(skb) + 1);
phlen = sizeof(*ph) + ph->padlen;
optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
if (optlen < 0 || optlen & 3 || optlen > 250)
goto out;
if (!pskb_may_pull(skb, phlen + optlen))
goto out;
skb->len -= phlen + optlen;
ph_nexthdr = ph->nexthdr;
}
skb_set_network_header(skb, phlen - sizeof(*iph));
memmove(skb_network_header(skb), iph, sizeof(*iph));
skb_set_transport_header(skb, phlen + optlen);
skb->data = skb_transport_header(skb);
iph = ip_hdr(skb);
iph->ihl = (sizeof(*iph) + optlen) / 4;
iph->tot_len = htons(skb->len + iph->ihl * 4);
iph->daddr = x->sel.daddr.a4;
iph->saddr = x->sel.saddr.a4;
if (ph_nexthdr)
iph->protocol = ph_nexthdr;
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 = {
.input = xfrm4_beet_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);