linux/net/ipv6/tunnel6.c
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   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
  35static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
  36static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
  37static DEFINE_MUTEX(tunnel6_mutex);
  38
  39int 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
  63err:
  64        mutex_unlock(&tunnel6_mutex);
  65
  66        return ret;
  67}
  68
  69EXPORT_SYMBOL(xfrm6_tunnel_register);
  70
  71int 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
  97EXPORT_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
 104static 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
 117drop:
 118        kfree_skb(skb);
 119        return 0;
 120}
 121
 122static 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
 135drop:
 136        kfree_skb(skb);
 137        return 0;
 138}
 139
 140static 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
 150static 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
 156static 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
 162static 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
 176static 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
 184module_init(tunnel6_init);
 185module_exit(tunnel6_fini);
 186MODULE_LICENSE("GPL");
 187
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