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 __rcu *tunnel6_handlers __read_mostly;
  34 static struct xfrm6_tunnel __rcu *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 __rcu **pprev;
  40         struct xfrm6_tunnel *t;
  41         int ret = -EEXIST;
  42         int priority = handler->priority;
  43
  44         mutex_lock(&tunnel6_mutex);
  45
  46         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
  47              (t = rcu_dereference_protected(*pprev,
  48                         lockdep_is_held(&tunnel6_mutex))) != NULL;
  49              pprev = &t->next) {
  50                 if (t->priority > priority)
  51                         break;
  52                 if (t->priority == priority)
  53                         goto err;
  54         }
  55
  56         handler->next = *pprev;
  57         rcu_assign_pointer(*pprev, handler);
  58
  59         ret = 0;
  60
  61 err:
  62         mutex_unlock(&tunnel6_mutex);
  63
  64         return ret;
  65 }
  66
  67 EXPORT_SYMBOL(xfrm6_tunnel_register);
  68
  69 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
  70 {
  71         struct xfrm6_tunnel __rcu **pprev;
  72         struct xfrm6_tunnel *t;
  73         int ret = -ENOENT;
  74
  75         mutex_lock(&tunnel6_mutex);
  76
  77         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
  78              (t = rcu_dereference_protected(*pprev,
  79                         lockdep_is_held(&tunnel6_mutex))) != NULL;
  80              pprev = &t->next) {
  81                 if (t == handler) {
  82                         *pprev = handler->next;
  83                         ret = 0;
  84                         break;
  85                 }
  86         }
  87
  88         mutex_unlock(&tunnel6_mutex);
  89
  90         synchronize_net();
  91
  92         return ret;
  93 }
  94
  95 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
  96
  97 #define for_each_tunnel_rcu(head, handler)              \
  98         for (handler = rcu_dereference(head);           \
  99              handler != NULL;                           \
 100              handler = rcu_dereference(handler->next))  \
 101
 102 static int tunnel6_rcv(struct sk_buff *skb)
 103 {
 104         struct xfrm6_tunnel *handler;
 105
 106         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 107                 goto drop;
 108
 109         for_each_tunnel_rcu(tunnel6_handlers, handler)
 110                 if (!handler->handler(skb))
 111                         return 0;
 112
 113         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 114
 115 drop:
 116         kfree_skb(skb);
 117         return 0;
 118 }
 119
 120 static int tunnel46_rcv(struct sk_buff *skb)
 121 {
 122         struct xfrm6_tunnel *handler;
 123
 124         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 125                 goto drop;
 126
 127         for_each_tunnel_rcu(tunnel46_handlers, handler)
 128                 if (!handler->handler(skb))
 129                         return 0;
 130
 131         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 132
 133 drop:
 134         kfree_skb(skb);
 135         return 0;
 136 }
 137
 138 static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 139                         u8 type, u8 code, int offset, __be32 info)
 140 {
 141         struct xfrm6_tunnel *handler;
 142
 143         for_each_tunnel_rcu(tunnel6_handlers, handler)
 144                 if (!handler->err_handler(skb, opt, type, code, offset, info))
 145                         break;
 146 }
 147
 148 static const struct inet6_protocol tunnel6_protocol = {
 149         .handler        = tunnel6_rcv,
 150         .err_handler    = tunnel6_err,
 151         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 152 };
 153
 154 static const struct inet6_protocol tunnel46_protocol = {
 155         .handler        = tunnel46_rcv,
 156         .err_handler    = tunnel6_err,
 157         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 158 };
 159
 160 static int __init tunnel6_init(void)
 161 {
 162         if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
 163                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 164                 return -EAGAIN;
 165         }
 166         if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
 167                 printk(KERN_ERR "tunnel6 init(): can't add protocol\n");
 168                 inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
 169                 return -EAGAIN;
 170         }
 171         return 0;
 172 }
 173
 174 static void __exit tunnel6_fini(void)
 175 {
 176         if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
 177                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 178         if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
 179                 printk(KERN_ERR "tunnel6 close: can't remove protocol\n");
 180 }
 181
 182 module_init(tunnel6_init);
 183 module_exit(tunnel6_fini);
 184 MODULE_LICENSE("GPL");