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 __read_mostly;
  34 static struct xfrm6_tunnel *tunnel46_handlers __read_mostly;
  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         rcu_assign_pointer(*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 #define for_each_tunnel_rcu(head, handler)              \
  92         for (handler = rcu_dereference(head);           \
  93              handler != NULL;                           \
  94              handler = rcu_dereference(handler->next))  \
  95
  96 static int tunnel6_rcv(struct sk_buff *skb)
  97 {
  98         struct xfrm6_tunnel *handler;
  99
 100         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 101                 goto drop;
 102
 103         for_each_tunnel_rcu(tunnel6_handlers, handler)
 104                 if (!handler->handler(skb))
 105                         return 0;
 106
 107         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 108
 109 drop:
 110         kfree_skb(skb);
 111         return 0;
 112 }
 113
 114 static int tunnel46_rcv(struct sk_buff *skb)
 115 {
 116         struct xfrm6_tunnel *handler;
 117
 118         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 119                 goto drop;
 120
 121         for_each_tunnel_rcu(tunnel46_handlers, handler)
 122                 if (!handler->handler(skb))
 123                         return 0;
 124
 125         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 126
 127 drop:
 128         kfree_skb(skb);
 129         return 0;
 130 }
 131
 132 static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 133                         u8 type, u8 code, int offset, __be32 info)
 134 {
 135         struct xfrm6_tunnel *handler;
 136
 137         for_each_tunnel_rcu(tunnel6_handlers, handler)
 138                 if (!handler->err_handler(skb, opt, type, code, offset, info))
 139                         break;
 140 }
 141
 142 static const struct inet6_protocol tunnel6_protocol = {
 143         .handler        = tunnel6_rcv,
 144         .err_handler    = tunnel6_err,
 145         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 146 };
 147
 148 static const struct inet6_protocol tunnel46_protocol = {
 149         .handler        = tunnel46_rcv,
 150         .err_handler    = tunnel6_err,
 151         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 152 };
 153
 154 static int __init tunnel6_init(void)
 155 {
 156         if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
 157                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 158                 return -EAGAIN;
 159         }
 160         if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
 161                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 162                 inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
 163                 return -EAGAIN;
 164         }
 165         return 0;
 166 }
 167
 168 static void __exit tunnel6_fini(void)
 169 {
 170         if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
 171                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 172         if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
 173                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 174 }
 175
 176 module_init(tunnel6_init);
 177 module_exit(tunnel6_fini);
 178 MODULE_LICENSE("GPL");