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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 static inline struct xfrm_tunnel **fam_handlers(unsigned short family)
  21 {
  22         return (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
  23 }
  24
  25 int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
  26 {
  27         struct xfrm_tunnel **pprev;
  28         int ret = -EEXIST;
  29         int priority = handler->priority;
  30
  31         mutex_lock(&tunnel4_mutex);
  32
  33         for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
  34                 if ((*pprev)->priority > priority)
  35                         break;
  36                 if ((*pprev)->priority == priority)
  37                         goto err;
  38         }
  39
  40         handler->next = *pprev;
  41         *pprev = handler;
  42
  43         ret = 0;
  44
  45 err:
  46         mutex_unlock(&tunnel4_mutex);
  47
  48         return ret;
  49 }
  50
  51 EXPORT_SYMBOL(xfrm4_tunnel_register);
  52
  53 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
  54 {
  55         struct xfrm_tunnel **pprev;
  56         int ret = -ENOENT;
  57
  58         mutex_lock(&tunnel4_mutex);
  59
  60         for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
  61                 if (*pprev == handler) {
  62                         *pprev = handler->next;
  63                         ret = 0;
  64                         break;
  65                 }
  66         }
  67
  68         mutex_unlock(&tunnel4_mutex);
  69
  70         synchronize_net();
  71
  72         return ret;
  73 }
  74
  75 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
  76
  77 static int tunnel4_rcv(struct sk_buff *skb)
  78 {
  79         struct xfrm_tunnel *handler;
  80
  81         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
  82                 goto drop;
  83
  84         for (handler = tunnel4_handlers; handler; handler = handler->next)
  85                 if (!handler->handler(skb))
  86                         return 0;
  87
  88         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
  89
  90 drop:
  91         kfree_skb(skb);
  92         return 0;
  93 }
  94
  95 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  96 static int tunnel64_rcv(struct sk_buff *skb)
  97 {
  98         struct xfrm_tunnel *handler;
  99
 100         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 101                 goto drop;
 102
 103         for (handler = tunnel64_handlers; handler; handler = handler->next)
 104                 if (!handler->handler(skb))
 105                         return 0;
 106
 107         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 108
 109 drop:
 110         kfree_skb(skb);
 111         return 0;
 112 }
 113 #endif
 114
 115 static void tunnel4_err(struct sk_buff *skb, u32 info)
 116 {
 117         struct xfrm_tunnel *handler;
 118
 119         for (handler = tunnel4_handlers; handler; handler = handler->next)
 120                 if (!handler->err_handler(skb, info))
 121                         break;
 122 }
 123
 124 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 125 static void tunnel64_err(struct sk_buff *skb, u32 info)
 126 {
 127         struct xfrm_tunnel *handler;
 128
 129         for (handler = tunnel64_handlers; handler; handler = handler->next)
 130                 if (!handler->err_handler(skb, info))
 131                         break;
 132 }
 133 #endif
 134
 135 static struct net_protocol tunnel4_protocol = {
 136         .handler        =       tunnel4_rcv,
 137         .err_handler    =       tunnel4_err,
 138         .no_policy      =       1,
 139         .netns_ok       =       1,
 140 };
 141
 142 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 143 static struct net_protocol tunnel64_protocol = {
 144         .handler        =       tunnel64_rcv,
 145         .err_handler    =       tunnel64_err,
 146         .no_policy      =       1,
 147         .netns_ok       =       1,
 148 };
 149 #endif
 150
 151 static int __init tunnel4_init(void)
 152 {
 153         if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
 154                 printk(KERN_ERR "tunnel4 init: can't add protocol\n");
 155                 return -EAGAIN;
 156         }
 157 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 158         if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
 159                 printk(KERN_ERR "tunnel64 init: can't add protocol\n");
 160                 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
 161                 return -EAGAIN;
 162         }
 163 #endif
 164         return 0;
 165 }
 166
 167 static void __exit tunnel4_fini(void)
 168 {
 169 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 170         if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
 171                 printk(KERN_ERR "tunnel64 close: can't remove protocol\n");
 172 #endif
 173         if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
 174                 printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
 175 }
 176
 177 module_init(tunnel4_init);
 178 module_exit(tunnel4_fini);
 179 MODULE_LICENSE("GPL");