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