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