net/ipv6/tunnel6.c

   1 /*
   2  * Copyright (C)2003,2004 USAGI/WIDE Project
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  * Authors      Mitsuru KANDA  <mk@linux-ipv6.org>
  19  *              YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
  20  */
  21
  22 #include <linux/icmpv6.h>
  23 #include <linux/init.h>
  24 #include <linux/module.h>
  25 #include <linux/mutex.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/skbuff.h>
  28 #include <net/ipv6.h>
  29 #include <net/protocol.h>
  30 #include <net/xfrm.h>
  31
  32 static struct xfrm6_tunnel *tunnel6_handlers;
  33 static DEFINE_MUTEX(tunnel6_mutex);
  34
  35 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler)
  36 {
  37         struct xfrm6_tunnel **pprev;
  38         int ret = -EEXIST;
  39         int priority = handler->priority;
  40
  41         mutex_lock(&tunnel6_mutex);
  42
  43         for (pprev = &tunnel6_handlers; *pprev; pprev = &(*pprev)->next) {
  44                 if ((*pprev)->priority > priority)
  45                         break;
  46                 if ((*pprev)->priority == priority)
  47                         goto err;
  48         }
  49
  50         handler->next = *pprev;
  51         *pprev = handler;
  52
  53         ret = 0;
  54
  55 err:
  56         mutex_unlock(&tunnel6_mutex);
  57
  58         return ret;
  59 }
  60
  61 EXPORT_SYMBOL(xfrm6_tunnel_register);
  62
  63 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler)
  64 {
  65         struct xfrm6_tunnel **pprev;
  66         int ret = -ENOENT;
  67
  68         mutex_lock(&tunnel6_mutex);
  69
  70         for (pprev = &tunnel6_handlers; *pprev; pprev = &(*pprev)->next) {
  71                 if (*pprev == handler) {
  72                         *pprev = handler->next;
  73                         ret = 0;
  74                         break;
  75                 }
  76         }
  77
  78         mutex_unlock(&tunnel6_mutex);
  79
  80         synchronize_net();
  81
  82         return ret;
  83 }
  84
  85 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
  86
  87 static int tunnel6_rcv(struct sk_buff **pskb)
  88 {
  89         struct sk_buff *skb = *pskb;
  90         struct xfrm6_tunnel *handler;
  91
  92         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  93                 goto drop;
  94
  95         for (handler = tunnel6_handlers; handler; handler = handler->next)
  96                 if (!handler->handler(skb))
  97                         return 0;
  98
  99         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0, skb->dev);
 100
 101 drop:
 102         kfree_skb(skb);
 103         return 0;
 104 }
 105
 106 static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 107                         int type, int code, int offset, __be32 info)
 108 {
 109         struct xfrm6_tunnel *handler;
 110
 111         for (handler = tunnel6_handlers; handler; handler = handler->next)
 112                 if (!handler->err_handler(skb, opt, type, code, offset, info))
 113                         break;
 114 }
 115
 116 static struct inet6_protocol tunnel6_protocol = {
 117         .handler        = tunnel6_rcv,
 118         .err_handler    = tunnel6_err,
 119         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 120 };
 121
 122 static int __init tunnel6_init(void)
 123 {
 124         if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
 125                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 126                 return -EAGAIN;
 127         }
 128         return 0;
 129 }
 130
 131 static void __exit tunnel6_fini(void)
 132 {
 133         if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
 134                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 135 }
 136
 137 module_init(tunnel6_init);
 138 module_exit(tunnel6_fini);
 139 MODULE_LICENSE("GPL");