125 lines
2.9 KiB
C
125 lines
2.9 KiB
C
/*
|
|
* xfrm4_mode_tunnel.c - Tunnel mode encapsulation for IPv4.
|
|
*
|
|
* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
|
|
*/
|
|
|
|
#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/inet_ecn.h>
|
|
#include <net/ip.h>
|
|
#include <net/xfrm.h>
|
|
|
|
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);
|
|
}
|
|
|
|
/* Add encapsulation header.
|
|
*
|
|
* The top IP header will be constructed per RFC 2401. The following fields
|
|
* in it shall be filled in by x->type->output:
|
|
* tot_len
|
|
* check
|
|
*
|
|
* On exit, skb->h will be set to the start of the payload to be processed
|
|
* by x->type->output and skb->nh will be set to the top IP header.
|
|
*/
|
|
static int xfrm4_tunnel_output(struct sk_buff *skb)
|
|
{
|
|
struct dst_entry *dst = skb->dst;
|
|
struct xfrm_state *x = dst->xfrm;
|
|
struct iphdr *iph, *top_iph;
|
|
int flags;
|
|
|
|
iph = skb->nh.iph;
|
|
skb->h.ipiph = iph;
|
|
|
|
skb->nh.raw = skb_push(skb, x->props.header_len);
|
|
top_iph = skb->nh.iph;
|
|
|
|
top_iph->ihl = 5;
|
|
top_iph->version = 4;
|
|
|
|
/* DS disclosed */
|
|
top_iph->tos = INET_ECN_encapsulate(iph->tos, iph->tos);
|
|
|
|
flags = x->props.flags;
|
|
if (flags & XFRM_STATE_NOECN)
|
|
IP_ECN_clear(top_iph);
|
|
|
|
top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
|
|
0 : (iph->frag_off & htons(IP_DF));
|
|
if (!top_iph->frag_off)
|
|
__ip_select_ident(top_iph, dst->child, 0);
|
|
|
|
top_iph->ttl = dst_metric(dst->child, RTAX_HOPLIMIT);
|
|
|
|
top_iph->saddr = x->props.saddr.a4;
|
|
top_iph->daddr = x->id.daddr.a4;
|
|
top_iph->protocol = IPPROTO_IPIP;
|
|
|
|
memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
|
|
return 0;
|
|
}
|
|
|
|
static int xfrm4_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
|
|
{
|
|
struct iphdr *iph = skb->nh.iph;
|
|
int err = -EINVAL;
|
|
|
|
if (iph->protocol != IPPROTO_IPIP)
|
|
goto out;
|
|
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
|
|
goto out;
|
|
|
|
if (skb_cloned(skb) &&
|
|
(err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
|
|
goto out;
|
|
|
|
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;
|
|
err = 0;
|
|
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static struct xfrm_mode xfrm4_tunnel_mode = {
|
|
.input = xfrm4_tunnel_input,
|
|
.output = xfrm4_tunnel_output,
|
|
.owner = THIS_MODULE,
|
|
.encap = XFRM_MODE_TUNNEL,
|
|
};
|
|
|
|
static int __init xfrm4_tunnel_init(void)
|
|
{
|
|
return xfrm_register_mode(&xfrm4_tunnel_mode, AF_INET);
|
|
}
|
|
|
|
static void __exit xfrm4_tunnel_exit(void)
|
|
{
|
|
int err;
|
|
|
|
err = xfrm_unregister_mode(&xfrm4_tunnel_mode, AF_INET);
|
|
BUG_ON(err);
|
|
}
|
|
|
|
module_init(xfrm4_tunnel_init);
|
|
module_exit(xfrm4_tunnel_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TUNNEL);
|