174 lines
4.2 KiB
C
174 lines
4.2 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
/*
|
||
|
* xfrm4_input.c
|
||
|
*
|
||
|
* Changes:
|
||
|
* YOSHIFUJI Hideaki @USAGI
|
||
|
* Split up af-specific portion
|
||
|
* Derek Atkins <derek@ihtfp.com>
|
||
|
* Add Encapsulation support
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
#include <linux/slab.h>
|
||
|
#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>
|
||
|
|
||
|
static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
|
||
|
struct sk_buff *skb)
|
||
|
{
|
||
|
return dst_input(skb);
|
||
|
}
|
||
|
|
||
|
static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
|
||
|
struct sk_buff *skb)
|
||
|
{
|
||
|
if (!skb_dst(skb)) {
|
||
|
const struct iphdr *iph = ip_hdr(skb);
|
||
|
|
||
|
if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
|
||
|
iph->tos, skb->dev))
|
||
|
goto drop;
|
||
|
}
|
||
|
|
||
|
if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
|
||
|
goto drop;
|
||
|
|
||
|
return 0;
|
||
|
drop:
|
||
|
kfree_skb(skb);
|
||
|
return NET_RX_DROP;
|
||
|
}
|
||
|
|
||
|
int xfrm4_transport_finish(struct sk_buff *skb, int async)
|
||
|
{
|
||
|
struct xfrm_offload *xo = xfrm_offload(skb);
|
||
|
struct iphdr *iph = ip_hdr(skb);
|
||
|
|
||
|
iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
|
||
|
|
||
|
#ifndef CONFIG_NETFILTER
|
||
|
if (!async)
|
||
|
return -iph->protocol;
|
||
|
#endif
|
||
|
|
||
|
__skb_push(skb, skb->data - skb_network_header(skb));
|
||
|
iph->tot_len = htons(skb->len);
|
||
|
ip_send_check(iph);
|
||
|
|
||
|
if (xo && (xo->flags & XFRM_GRO)) {
|
||
|
skb_mac_header_rebuild(skb);
|
||
|
skb_reset_transport_header(skb);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
|
||
|
dev_net(skb->dev), NULL, skb, skb->dev, NULL,
|
||
|
xfrm4_rcv_encap_finish);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/* If it's a keepalive packet, then just eat it.
|
||
|
* If it's an encapsulated packet, then pass it to the
|
||
|
* IPsec xfrm input.
|
||
|
* Returns 0 if skb passed to xfrm or was dropped.
|
||
|
* Returns >0 if skb should be passed to UDP.
|
||
|
* Returns <0 if skb should be resubmitted (-ret is protocol)
|
||
|
*/
|
||
|
int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
|
||
|
{
|
||
|
struct udp_sock *up = udp_sk(sk);
|
||
|
struct udphdr *uh;
|
||
|
struct iphdr *iph;
|
||
|
int iphlen, len;
|
||
|
|
||
|
__u8 *udpdata;
|
||
|
__be32 *udpdata32;
|
||
|
__u16 encap_type = up->encap_type;
|
||
|
|
||
|
/* if this is not encapsulated socket, then just return now */
|
||
|
if (!encap_type)
|
||
|
return 1;
|
||
|
|
||
|
/* If this is a paged skb, make sure we pull up
|
||
|
* whatever data we need to look at. */
|
||
|
len = skb->len - sizeof(struct udphdr);
|
||
|
if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
|
||
|
return 1;
|
||
|
|
||
|
/* Now we can get the pointers */
|
||
|
uh = udp_hdr(skb);
|
||
|
udpdata = (__u8 *)uh + sizeof(struct udphdr);
|
||
|
udpdata32 = (__be32 *)udpdata;
|
||
|
|
||
|
switch (encap_type) {
|
||
|
default:
|
||
|
case UDP_ENCAP_ESPINUDP:
|
||
|
/* Check if this is a keepalive packet. If so, eat it. */
|
||
|
if (len == 1 && udpdata[0] == 0xff) {
|
||
|
goto drop;
|
||
|
} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
|
||
|
/* ESP Packet without Non-ESP header */
|
||
|
len = sizeof(struct udphdr);
|
||
|
} else
|
||
|
/* Must be an IKE packet.. pass it through */
|
||
|
return 1;
|
||
|
break;
|
||
|
case UDP_ENCAP_ESPINUDP_NON_IKE:
|
||
|
/* Check if this is a keepalive packet. If so, eat it. */
|
||
|
if (len == 1 && udpdata[0] == 0xff) {
|
||
|
goto drop;
|
||
|
} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
|
||
|
udpdata32[0] == 0 && udpdata32[1] == 0) {
|
||
|
|
||
|
/* ESP Packet with Non-IKE marker */
|
||
|
len = sizeof(struct udphdr) + 2 * sizeof(u32);
|
||
|
} else
|
||
|
/* Must be an IKE packet.. pass it through */
|
||
|
return 1;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
/* At this point we are sure that this is an ESPinUDP packet,
|
||
|
* so we need to remove 'len' bytes from the packet (the UDP
|
||
|
* header and optional ESP marker bytes) and then modify the
|
||
|
* protocol to ESP, and then call into the transform receiver.
|
||
|
*/
|
||
|
if (skb_unclone(skb, GFP_ATOMIC))
|
||
|
goto drop;
|
||
|
|
||
|
/* Now we can update and verify the packet length... */
|
||
|
iph = ip_hdr(skb);
|
||
|
iphlen = iph->ihl << 2;
|
||
|
iph->tot_len = htons(ntohs(iph->tot_len) - len);
|
||
|
if (skb->len < iphlen + len) {
|
||
|
/* packet is too small!?! */
|
||
|
goto drop;
|
||
|
}
|
||
|
|
||
|
/* pull the data buffer up to the ESP header and set the
|
||
|
* transport header to point to ESP. Keep UDP on the stack
|
||
|
* for later.
|
||
|
*/
|
||
|
__skb_pull(skb, len);
|
||
|
skb_reset_transport_header(skb);
|
||
|
|
||
|
/* process ESP */
|
||
|
return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
|
||
|
|
||
|
drop:
|
||
|
kfree_skb(skb);
|
||
|
return 0;
|
||
|
}
|
||
|
EXPORT_SYMBOL(xfrm4_udp_encap_rcv);
|
||
|
|
||
|
int xfrm4_rcv(struct sk_buff *skb)
|
||
|
{
|
||
|
return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
|
||
|
}
|
||
|
EXPORT_SYMBOL(xfrm4_rcv);
|