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 #define pr_fmt(fmt) "IPv6: " fmt
  23
  24 #include <linux/icmpv6.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/mutex.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/slab.h>
  31 #include <net/ipv6.h>
  32 #include <net/protocol.h>
  33 #include <net/xfrm.h>
  34
  35 static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
  36 static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
  37 static DEFINE_MUTEX(tunnel6_mutex);
  38
  39 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
  40 {
  41         struct xfrm6_tunnel __rcu **pprev;
  42         struct xfrm6_tunnel *t;
  43         int ret = -EEXIST;
  44         int priority = handler->priority;
  45
  46         mutex_lock(&tunnel6_mutex);
  47
  48         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
  49              (t = rcu_dereference_protected(*pprev,
  50                         lockdep_is_held(&tunnel6_mutex))) != NULL;
  51              pprev = &t->next) {
  52                 if (t->priority > priority)
  53                         break;
  54                 if (t->priority == priority)
  55                         goto err;
  56         }
  57
  58         handler->next = *pprev;
  59         rcu_assign_pointer(*pprev, handler);
  60
  61         ret = 0;
  62
  63 err:
  64         mutex_unlock(&tunnel6_mutex);
  65
  66         return ret;
  67 }
  68
  69 EXPORT_SYMBOL(xfrm6_tunnel_register);
  70
  71 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
  72 {
  73         struct xfrm6_tunnel __rcu **pprev;
  74         struct xfrm6_tunnel *t;
  75         int ret = -ENOENT;
  76
  77         mutex_lock(&tunnel6_mutex);
  78
  79         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
  80              (t = rcu_dereference_protected(*pprev,
  81                         lockdep_is_held(&tunnel6_mutex))) != NULL;
  82              pprev = &t->next) {
  83                 if (t == handler) {
  84                         *pprev = handler->next;
  85                         ret = 0;
  86                         break;
  87                 }
  88         }
  89
  90         mutex_unlock(&tunnel6_mutex);
  91
  92         synchronize_net();
  93
  94         return ret;
  95 }
  96
  97 EXPORT_SYMBOL(xfrm6_tunnel_deregister);
  98
  99 #define for_each_tunnel_rcu(head, handler)              \
 100         for (handler = rcu_dereference(head);           \
 101              handler != NULL;                           \
 102              handler = rcu_dereference(handler->next))  \
 103
 104 static int tunnel6_rcv(struct sk_buff *skb)
 105 {
 106         struct xfrm6_tunnel *handler;
 107
 108         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 109                 goto drop;
 110
 111         for_each_tunnel_rcu(tunnel6_handlers, handler)
 112                 if (!handler->handler(skb))
 113                         return 0;
 114
 115         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 116
 117 drop:
 118         kfree_skb(skb);
 119         return 0;
 120 }
 121
 122 static int tunnel46_rcv(struct sk_buff *skb)
 123 {
 124         struct xfrm6_tunnel *handler;
 125
 126         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 127                 goto drop;
 128
 129         for_each_tunnel_rcu(tunnel46_handlers, handler)
 130                 if (!handler->handler(skb))
 131                         return 0;
 132
 133         icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
 134
 135 drop:
 136         kfree_skb(skb);
 137         return 0;
 138 }
 139
 140 static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 141                         u8 type, u8 code, int offset, __be32 info)
 142 {
 143         struct xfrm6_tunnel *handler;
 144
 145         for_each_tunnel_rcu(tunnel6_handlers, handler)
 146                 if (!handler->err_handler(skb, opt, type, code, offset, info))
 147                         break;
 148 }
 149
 150 static const struct inet6_protocol tunnel6_protocol = {
 151         .handler        = tunnel6_rcv,
 152         .err_handler    = tunnel6_err,
 153         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 154 };
 155
 156 static const struct inet6_protocol tunnel46_protocol = {
 157         .handler        = tunnel46_rcv,
 158         .err_handler    = tunnel6_err,
 159         .flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
 160 };
 161
 162 static int __init tunnel6_init(void)
 163 {
 164         if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
 165                 pr_err("%s: can't add protocol\n", __func__);
 166                 return -EAGAIN;
 167         }
 168         if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
 169                 pr_err("%s: can't add protocol\n", __func__);
 170                 inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
 171                 return -EAGAIN;
 172         }
 173         return 0;
 174 }
 175
 176 static void __exit tunnel6_fini(void)
 177 {
 178         if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
 179                 pr_err("%s: can't remove protocol\n", __func__);
 180         if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
 181                 pr_err("%s: can't remove protocol\n", __func__);
 182 }
 183
 184 module_init(tunnel6_init);
 185 module_exit(tunnel6_fini);
 186 MODULE_LICENSE("GPL");