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   1 /* tunnel4.c: Generic IP tunnel transformer.
   2  *
   3  * Copyright (C) 2003 David S. Miller (davem@redhat.com)
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/module.h>
   8 #include <linux/mutex.h>
   9 #include <linux/netdevice.h>
  10 #include <linux/skbuff.h>
  11 #include <net/icmp.h>
  12 #include <net/ip.h>
  13 #include <net/protocol.h>
  14 #include <net/xfrm.h>
  15
  16 static struct xfrm_tunnel *tunnel4_handlers;
  17 static struct xfrm_tunnel *tunnel64_handlers;
  18 static DEFINE_MUTEX(tunnel4_mutex);
  19
  20 int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
  21 {
  22         struct xfrm_tunnel **pprev;
  23         int ret = -EEXIST;
  24         int priority = handler->priority;
  25
  26         mutex_lock(&tunnel4_mutex);
  27
  28         for (pprev = (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
  29              *pprev; pprev = &(*pprev)->next) {
  30                 if ((*pprev)->priority > priority)
  31                         break;
  32                 if ((*pprev)->priority == priority)
  33                         goto err;
  34         }
  35
  36         handler->next = *pprev;
  37         *pprev = handler;
  38
  39         ret = 0;
  40
  41 err:
  42         mutex_unlock(&tunnel4_mutex);
  43
  44         return ret;
  45 }
  46
  47 EXPORT_SYMBOL(xfrm4_tunnel_register);
  48
  49 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
  50 {
  51         struct xfrm_tunnel **pprev;
  52         int ret = -ENOENT;
  53
  54         mutex_lock(&tunnel4_mutex);
  55
  56         for (pprev = (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
  57              *pprev; pprev = &(*pprev)->next) {
  58                 if (*pprev == handler) {
  59                         *pprev = handler->next;
  60                         ret = 0;
  61                         break;
  62                 }
  63         }
  64
  65         mutex_unlock(&tunnel4_mutex);
  66
  67         synchronize_net();
  68
  69         return ret;
  70 }
  71
  72 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
  73
  74 static int tunnel4_rcv(struct sk_buff *skb)
  75 {
  76         struct xfrm_tunnel *handler;
  77
  78         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
  79                 goto drop;
  80
  81         for (handler = tunnel4_handlers; handler; handler = handler->next)
  82                 if (!handler->handler(skb))
  83                         return 0;
  84
  85         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
  86
  87 drop:
  88         kfree_skb(skb);
  89         return 0;
  90 }
  91
  92 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  93 static int tunnel64_rcv(struct sk_buff *skb)
  94 {
  95         struct xfrm_tunnel *handler;
  96
  97         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
  98                 goto drop;
  99
 100         for (handler = tunnel64_handlers; handler; handler = handler->next)
 101                 if (!handler->handler(skb))
 102                         return 0;
 103
 104         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 105
 106 drop:
 107         kfree_skb(skb);
 108         return 0;
 109 }
 110 #endif
 111
 112 static void tunnel4_err(struct sk_buff *skb, u32 info)
 113 {
 114         struct xfrm_tunnel *handler;
 115
 116         for (handler = tunnel4_handlers; handler; handler = handler->next)
 117                 if (!handler->err_handler(skb, info))
 118                         break;
 119 }
 120
 121 static struct net_protocol tunnel4_protocol = {
 122         .handler        =       tunnel4_rcv,
 123         .err_handler    =       tunnel4_err,
 124         .no_policy      =       1,
 125 };
 126
 127 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 128 static struct net_protocol tunnel64_protocol = {
 129         .handler        =       tunnel64_rcv,
 130         .err_handler    =       tunnel4_err,
 131         .no_policy      =       1,
 132 };
 133 #endif
 134
 135 static int __init tunnel4_init(void)
 136 {
 137         if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
 138                 printk(KERN_ERR "tunnel4 init: can't add protocol\n");
 139                 return -EAGAIN;
 140         }
 141 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 142         if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
 143                 printk(KERN_ERR "tunnel64 init: can't add protocol\n");
 144                 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
 145                 return -EAGAIN;
 146         }
 147 #endif
 148         return 0;
 149 }
 150
 151 static void __exit tunnel4_fini(void)
 152 {
 153 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 154         if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
 155                 printk(KERN_ERR "tunnel64 close: can't remove protocol\n");
 156 #endif
 157         if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
 158                 printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
 159 }
 160
 161 module_init(tunnel4_init);
 162 module_exit(tunnel4_fini);
 163 MODULE_LICENSE("GPL");