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/*
* xfrm4_input.c
*
* Changes:
* YOSHIFUJI Hideaki @USAGI
* Split up af-specific portion
* Derek Atkins <derek@ihtfp.com>
* Add Encapsulation support
*
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <net/ip.h>
#include <net/xfrm.h>
int xfrm4_rcv(struct sk_buff *skb)
{
return xfrm4_rcv_encap(skb, 0);
}
EXPORT_SYMBOL(xfrm4_rcv);
static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
{
switch (nexthdr) {
case IPPROTO_IPIP:
case IPPROTO_IPV6:
*spi = ip_hdr(skb)->saddr;
*seq = 0;
return 0;
}
return xfrm_parse_spi(skb, nexthdr, spi, seq);
}
#ifdef CONFIG_NETFILTER
static inline int xfrm4_rcv_encap_finish(struct sk_buff *skb)
{
if (skb->dst == NULL) {
const struct iphdr *iph = ip_hdr(skb);
if (ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
skb->dev))
goto drop;
}
return dst_input(skb);
drop:
kfree_skb(skb);
return NET_RX_DROP;
}
#endif
int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
{
__be32 spi, seq;
struct xfrm_state *xfrm_vec[XFRM_MAX_DEPTH];
struct xfrm_state *x;
int xfrm_nr = 0;
int decaps = 0;
int err = xfrm4_parse_spi(skb, ip_hdr(skb)->protocol, &spi, &seq);
if (err != 0)
goto drop;
do {
const struct iphdr *iph = ip_hdr(skb);
if (xfrm_nr == XFRM_MAX_DEPTH)
goto drop;
x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi,
iph->protocol != IPPROTO_IPV6 ? iph->protocol : IPPROTO_IPIP, AF_INET);
if (x == NULL)
goto drop;
spin_lock(&x->lock);
if (unlikely(x->km.state != XFRM_STATE_VALID))
goto drop_unlock;
if ((x->encap ? x->encap->encap_type : 0) != encap_type)
goto drop_unlock;
if (x->props.replay_window && xfrm_replay_check(x, seq))
goto drop_unlock;
if (xfrm_state_check_expire(x))
goto drop_unlock;
if (x->type->input(x, skb))
goto drop_unlock;
/* only the first xfrm gets the encap type */
encap_type = 0;
if (x->props.replay_window)
xfrm_replay_advance(x, seq);
x->curlft.bytes += skb->len;
x->curlft.packets++;
spin_unlock(&x->lock);
xfrm_vec[xfrm_nr++] = x;
if (x->mode->input(x, skb))
goto drop;
if (x->props.mode == XFRM_MODE_TUNNEL) {
decaps = 1;
break;
}
err = xfrm_parse_spi(skb, ip_hdr(skb)->protocol, &spi, &seq);
if (err < 0)
goto drop;
} while (!err);
/* Allocate new secpath or COW existing one. */
if (!skb->sp || atomic_read(&skb->sp->refcnt) != 1) {
struct sec_path *sp;
sp = secpath_dup(skb->sp);
if (!sp)
goto drop;
if (skb->sp)
secpath_put(skb->sp);
skb->sp = sp;
}
if (xfrm_nr + skb->sp->len > XFRM_MAX_DEPTH)
goto drop;
memcpy(skb->sp->xvec + skb->sp->len, xfrm_vec,
xfrm_nr * sizeof(xfrm_vec[0]));
skb->sp->len += xfrm_nr;
nf_reset(skb);
if (decaps) {
dst_release(skb->dst);
skb->dst = NULL;
netif_rx(skb);
return 0;
} else {
#ifdef CONFIG_NETFILTER
__skb_push(skb, skb->data - skb_network_header(skb));
ip_hdr(skb)->tot_len = htons(skb->len);
ip_send_check(ip_hdr(skb));
NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
xfrm4_rcv_encap_finish);
return 0;
#else
return -ip_hdr(skb)->protocol;
#endif
}
drop_unlock:
spin_unlock(&x->lock);
xfrm_state_put(x);
drop:
while (--xfrm_nr >= 0)
xfrm_state_put(xfrm_vec[xfrm_nr]);
kfree_skb(skb);
return 0;
}
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