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/init.h>
  23 #include <linux/module.h>
  24 #include <linux/mutex.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/skbuff.h>
  27 #include <net/protocol.h>
  28 #include <net/xfrm.h>
  29
  30 static struct xfrm6_tunnel *tunnel6_handlers;
  31 static DEFINE_MUTEX(tunnel6_mutex);
  32
  33 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler)
  34 {
  35         struct xfrm6_tunnel **pprev;
  36         int ret = -EEXIST;
  37         int priority = handler->priority;
  38
  39         mutex_lock(&tunnel6_mutex);
  40
  41         for (pprev = &tunnel6_handlers; *pprev; pprev = &(*pprev)->next) {
  42                 if ((*pprev)->priority > priority)
  43                         break;
  44                 if ((*pprev)->priority == priority)
  45                         goto err;
  46         }
  47
  48         handler->next = *pprev;
  49         *pprev = handler;
  50
  51         ret = 0;
  52
  53 err:
  54         mutex_unlock(&tunnel6_mutex);
  55
  56         return ret;
  57 }
  58
  59 EXPORT_SYMBOL(xfrm6_tunnel_register);
  60
  61 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler)
  62 {
  63         struct xfrm6_tunnel **pprev;
  64         int ret = -ENOENT;
  65
  66         mutex_lock(&tunnel6_mutex);
  67
  68         for (pprev = &tunnel6_handlers; *pprev; pprev = &(*pprev)->next) {
  69                 if (*pprev == handler) {
  70                         *pprev = handler->next;
  71                         ret = 0;
  72                         break;
  73                 }
  74         }
  75
  76         mutex_unlock(&tunnel6_mutex);
  77
  78         synchronize_net();
  79
  80         return ret;
  81 }
  82
  83 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
  84
  85 static int tunnel6_rcv(struct sk_buff **pskb)
  86 {
  87         struct sk_buff *skb = *pskb;
  88         struct xfrm6_tunnel *handler;
  89
  90         for (handler = tunnel6_handlers; handler; handler = handler->next)
  91                 if (!handler->handler(skb))
  92                         return 0;
  93
  94         kfree_skb(skb);
  95         return 0;
  96 }
  97
  98 static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  99                         int type, int code, int offset, __u32 info)
 100 {
 101         struct xfrm6_tunnel *handler;
 102
 103         for (handler = tunnel6_handlers; handler; handler = handler->next)
 104                 if (!handler->err_handler(skb, opt, type, code, offset, info))
 105                         break;
 106 }
 107
 108 static struct inet6_protocol tunnel6_protocol = {
 109         .handler        = tunnel6_rcv,
 110         .err_handler    = tunnel6_err,
 111         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 112 };
 113
 114 static int __init tunnel6_init(void)
 115 {
 116         if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
 117                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 118                 return -EAGAIN;
 119         }
 120         return 0;
 121 }
 122
 123 static void __exit tunnel6_fini(void)
 124 {
 125         if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
 126                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 127 }
 128
 129 module_init(tunnel6_init);
 130 module_exit(tunnel6_fini);
 131 MODULE_LICENSE("GPL");