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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/inet_ecn.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 inline void ipip_ecn_decapsulate(struct sk_buff *skb)
{
struct iphdr *outer_iph = skb->nh.iph;
struct iphdr *inner_iph = skb->h.ipiph;
if (INET_ECN_is_ce(outer_iph->tos))
IP_ECN_set_ce(inner_iph);
}
static int xfrm4_parse_spi(struct sk_buff *skb, u8 nexthdr, u32 *spi, u32 *seq)
{
switch (nexthdr) {
case IPPROTO_IPIP:
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
return -EINVAL;
*spi = skb->nh.iph->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)
{
struct iphdr *iph = skb->nh.iph;
if (skb->dst == NULL) {
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)
{
int err;
u32 spi, seq;
struct sec_decap_state xfrm_vec[XFRM_MAX_DEPTH];
struct xfrm_state *x;
int xfrm_nr = 0;
int decaps = 0;
if ((err = xfrm4_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) != 0)
goto drop;
do {
struct iphdr *iph = skb->nh.iph;
if (xfrm_nr == XFRM_MAX_DEPTH)
goto drop;
x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, spi, iph->protocol, 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->encap_type != 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;
xfrm_vec[xfrm_nr].decap.decap_type = encap_type;
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++].xvec = x;
iph = skb->nh.iph;
if (x->props.mode) {
if (iph->protocol != IPPROTO_IPIP)
goto drop;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto drop;
if (skb_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
goto drop;
if (x->props.flags & XFRM_STATE_DECAP_DSCP)
ipv4_copy_dscp(iph, skb->h.ipiph);
if (!(x->props.flags & XFRM_STATE_NOECN))
ipip_ecn_decapsulate(skb);
skb->mac.raw = memmove(skb->data - skb->mac_len,
skb->mac.raw, skb->mac_len);
skb->nh.raw = skb->data;
memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
decaps = 1;
break;
}
if ((err = xfrm_parse_spi(skb, skb->nh.iph->protocol, &spi, &seq)) < 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->x+skb->sp->len, xfrm_vec, xfrm_nr*sizeof(struct sec_decap_state));
skb->sp->len += xfrm_nr;
nf_reset(skb);
if (decaps) {
if (!(skb->dev->flags&IFF_LOOPBACK)) {
dst_release(skb->dst);
skb->dst = NULL;
}
netif_rx(skb);
return 0;
} else {
#ifdef CONFIG_NETFILTER
__skb_push(skb, skb->data - skb->nh.raw);
skb->nh.iph->tot_len = htons(skb->len);
ip_send_check(skb->nh.iph);
NF_HOOK(PF_INET, NF_IP_PRE_ROUTING, skb, skb->dev, NULL,
xfrm4_rcv_encap_finish);
return 0;
#else
return -skb->nh.iph->protocol;
#endif
}
drop_unlock:
spin_unlock(&x->lock);
xfrm_state_put(x);
drop:
while (--xfrm_nr >= 0)
xfrm_state_put(xfrm_vec[xfrm_nr].xvec);
kfree_skb(skb);
return 0;
}
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