tunnel4.c
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/* tunnel4.c: Generic IP tunnel transformer.
*
* Copyright (C) 2003 David S. Miller (davem@redhat.com)
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/xfrm.h>
static struct xfrm_tunnel *tunnel4_handlers;
static DEFINE_MUTEX(tunnel4_mutex);
int xfrm4_tunnel_register(struct xfrm_tunnel *handler)
{
struct xfrm_tunnel **pprev;
int ret = -EEXIST;
int priority = handler->priority;
mutex_lock(&tunnel4_mutex);
for (pprev = &tunnel4_handlers; *pprev; pprev = &(*pprev)->next) {
if ((*pprev)->priority > priority)
break;
if ((*pprev)->priority == priority)
goto err;
}
handler->next = *pprev;
*pprev = handler;
ret = 0;
err:
mutex_unlock(&tunnel4_mutex);
return ret;
}
EXPORT_SYMBOL(xfrm4_tunnel_register);
int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler)
{
struct xfrm_tunnel **pprev;
int ret = -ENOENT;
mutex_lock(&tunnel4_mutex);
for (pprev = &tunnel4_handlers; *pprev; pprev = &(*pprev)->next) {
if (*pprev == handler) {
*pprev = handler->next;
ret = 0;
break;
}
}
mutex_unlock(&tunnel4_mutex);
synchronize_net();
return ret;
}
EXPORT_SYMBOL(xfrm4_tunnel_deregister);
static int tunnel4_rcv(struct sk_buff *skb)
{
struct xfrm_tunnel *handler;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto drop;
for (handler = tunnel4_handlers; handler; handler = handler->next)
if (!handler->handler(skb))
return 0;
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
drop:
kfree_skb(skb);
return 0;
}
static void tunnel4_err(struct sk_buff *skb, u32 info)
{
struct xfrm_tunnel *handler;
for (handler = tunnel4_handlers; handler; handler = handler->next)
if (!handler->err_handler(skb, info))
break;
}
static struct net_protocol tunnel4_protocol = {
.handler = tunnel4_rcv,
.err_handler = tunnel4_err,
.no_policy = 1,
};
static int __init tunnel4_init(void)
{
if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
printk(KERN_ERR "tunnel4 init: can't add protocol\n");
return -EAGAIN;
}
return 0;
}
static void __exit tunnel4_fini(void)
{
if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
}
module_init(tunnel4_init);
module_exit(tunnel4_fini);
MODULE_LICENSE("GPL");