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 <linux/slab.h>
  29 #include <net/ipv6.h>
  30 #include <net/protocol.h>
  31 #include <net/xfrm.h>
  32
  33 static struct xfrm6_tunnel *tunnel6_handlers;
  34 static struct xfrm6_tunnel *tunnel46_handlers;
  35 static DEFINE_MUTEX(tunnel6_mutex);
  36
  37 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
  38 {
  39         struct xfrm6_tunnel **pprev;
  40         int ret = -EEXIST;
  41         int priority = handler->priority;
  42
  43         mutex_lock(&tunnel6_mutex);
  44
  45         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
  46              *pprev; pprev = &(*pprev)->next) {
  47                 if ((*pprev)->priority > priority)
  48                         break;
  49                 if ((*pprev)->priority == priority)
  50                         goto err;
  51         }
  52
  53         handler->next = *pprev;
  54         *pprev = handler;
  55
  56         ret = 0;
  57
  58 err:
  59         mutex_unlock(&tunnel6_mutex);
  60
  61         return ret;
  62 }
  63
  64 EXPORT_SYMBOL(xfrm6_tunnel_register);
  65
  66 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
  67 {
  68         struct xfrm6_tunnel **pprev;
  69         int ret = -ENOENT;
  70
  71         mutex_lock(&tunnel6_mutex);
  72
  73         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
  74              *pprev; pprev = &(*pprev)->next) {
  75                 if (*pprev == handler) {
  76                         *pprev = handler->next;
  77                         ret = 0;
  78                         break;
  79                 }
  80         }
  81
  82         mutex_unlock(&tunnel6_mutex);
  83
  84         synchronize_net();
  85
  86         return ret;
  87 }
  88
  89 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
  90
  91 static int tunnel6_rcv(struct sk_buff *skb)
  92 {
  93         struct xfrm6_tunnel *handler;
  94
  95         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  96                 goto drop;
  97
  98         for (handler = tunnel6_handlers; handler; handler = handler->next)
  99                 if (!handler->handler(skb))
 100                         return 0;
 101
 102         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 103
 104 drop:
 105         kfree_skb(skb);
 106         return 0;
 107 }
 108
 109 static int tunnel46_rcv(struct sk_buff *skb)
 110 {
 111         struct xfrm6_tunnel *handler;
 112
 113         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 114                 goto drop;
 115
 116         for (handler = tunnel46_handlers; handler; handler = handler->next)
 117                 if (!handler->handler(skb))
 118                         return 0;
 119
 120         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 121
 122 drop:
 123         kfree_skb(skb);
 124         return 0;
 125 }
 126
 127 static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 128                         u8 type, u8 code, int offset, __be32 info)
 129 {
 130         struct xfrm6_tunnel *handler;
 131
 132         for (handler = tunnel6_handlers; handler; handler = handler->next)
 133                 if (!handler->err_handler(skb, opt, type, code, offset, info))
 134                         break;
 135 }
 136
 137 static const struct inet6_protocol tunnel6_protocol = {
 138         .handler        = tunnel6_rcv,
 139         .err_handler    = tunnel6_err,
 140         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 141 };
 142
 143 static const struct inet6_protocol tunnel46_protocol = {
 144         .handler        = tunnel46_rcv,
 145         .err_handler    = tunnel6_err,
 146         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 147 };
 148
 149 static int __init tunnel6_init(void)
 150 {
 151         if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
 152                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 153                 return -EAGAIN;
 154         }
 155         if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
 156                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 157                 inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
 158                 return -EAGAIN;
 159         }
 160         return 0;
 161 }
 162
 163 static void __exit tunnel6_fini(void)
 164 {
 165         if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
 166                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 167         if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
 168                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 169 }
 170
 171 module_init(tunnel6_init);
 172 module_exit(tunnel6_fini);
 173 MODULE_LICENSE("GPL");