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// SPDX-License-Identifier: GPL-2.0
/*
* xfrm6_input.c: based on net/ipv4/xfrm4_input.c
*
* Authors:
* Mitsuru KANDA @USAGI
* Kazunori MIYAZAWA @USAGI
* Kunihiro Ishiguro <kunihiro@ipinfusion.com>
* YOSHIFUJI Hideaki @USAGI
* IPv6 support
*/
#include <linux/module.h>
#include <linux/string.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <net/ipv6.h>
#include <net/xfrm.h>
int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi,
struct ip6_tnl *t)
{
XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = t;
XFRM_SPI_SKB_CB(skb)->family = AF_INET6;
XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct ipv6hdr, daddr);
return xfrm_input(skb, nexthdr, spi, 0);
}
EXPORT_SYMBOL(xfrm6_rcv_spi);
static int xfrm6_transport_finish2(struct net *net, struct sock *sk,
struct sk_buff *skb)
{
if (xfrm_trans_queue(skb, ip6_rcv_finish)) {
kfree_skb(skb);
return NET_RX_DROP;
}
return 0;
}
int xfrm6_transport_finish(struct sk_buff *skb, int async)
{
struct xfrm_offload *xo = xfrm_offload(skb);
int nhlen = skb->data - skb_network_header(skb);
skb_network_header(skb)[IP6CB(skb)->nhoff] =
XFRM_MODE_SKB_CB(skb)->protocol;
#ifndef CONFIG_NETFILTER
if (!async)
return 1;
#endif
__skb_push(skb, nhlen);
ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
skb_postpush_rcsum(skb, skb_network_header(skb), nhlen);
if (xo && (xo->flags & XFRM_GRO)) {
skb_mac_header_rebuild(skb);
skb_reset_transport_header(skb);
return 0;
}
NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
dev_net(skb->dev), NULL, skb, skb->dev, NULL,
xfrm6_transport_finish2);
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 xfrm6_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
{
struct udp_sock *up = udp_sk(sk);
struct udphdr *uh;
struct ipv6hdr *ip6h;
int len;
int ip6hlen = sizeof(struct ipv6hdr);
__u8 *udpdata;
__be32 *udpdata32;
__u16 encap_type = up->encap_type;
if (skb->protocol == htons(ETH_P_IP))
return xfrm4_udp_encap_rcv(sk, skb);
/* 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... */
ip6h = ipv6_hdr(skb);
ip6h->payload_len = htons(ntohs(ip6h->payload_len) - len);
if (skb->len < ip6hlen + 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 xfrm6_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
drop:
kfree_skb(skb);
return 0;
}
int xfrm6_rcv_tnl(struct sk_buff *skb, struct ip6_tnl *t)
{
return xfrm6_rcv_spi(skb, skb_network_header(skb)[IP6CB(skb)->nhoff],
0, t);
}
EXPORT_SYMBOL(xfrm6_rcv_tnl);
int xfrm6_rcv(struct sk_buff *skb)
{
return xfrm6_rcv_tnl(skb, NULL);
}
EXPORT_SYMBOL(xfrm6_rcv);
int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
xfrm_address_t *saddr, u8 proto)
{
struct net *net = dev_net(skb->dev);
struct xfrm_state *x = NULL;
struct sec_path *sp;
int i = 0;
sp = secpath_set(skb);
if (!sp) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINERROR);
goto drop;
}
if (1 + sp->len == XFRM_MAX_DEPTH) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto drop;
}
for (i = 0; i < 3; i++) {
xfrm_address_t *dst, *src;
switch (i) {
case 0:
dst = daddr;
src = saddr;
break;
case 1:
/* lookup state with wild-card source address */
dst = daddr;
src = (xfrm_address_t *)&in6addr_any;
break;
default:
/* lookup state with wild-card addresses */
dst = (xfrm_address_t *)&in6addr_any;
src = (xfrm_address_t *)&in6addr_any;
break;
}
x = xfrm_state_lookup_byaddr(net, skb->mark, dst, src, proto, AF_INET6);
if (!x)
continue;
spin_lock(&x->lock);
if ((!i || (x->props.flags & XFRM_STATE_WILDRECV)) &&
likely(x->km.state == XFRM_STATE_VALID) &&
!xfrm_state_check_expire(x)) {
spin_unlock(&x->lock);
if (x->type->input(x, skb) > 0) {
/* found a valid state */
break;
}
} else
spin_unlock(&x->lock);
xfrm_state_put(x);
x = NULL;
}
if (!x) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOSTATES);
xfrm_audit_state_notfound_simple(skb, AF_INET6);
goto drop;
}
sp->xvec[sp->len++] = x;
spin_lock(&x->lock);
x->curlft.bytes += skb->len;
x->curlft.packets++;
spin_unlock(&x->lock);
return 1;
drop:
return -1;
}
EXPORT_SYMBOL(xfrm6_input_addr);
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