net/ipv4/tunnel4.c

   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 <linux/slab.h>
  12 #include <net/icmp.h>
  13 #include <net/ip.h>
  14 #include <net/protocol.h>
  15 #include <net/xfrm.h>
  16
  17 static struct xfrm_tunnel *tunnel4_handlers;
  18 static struct xfrm_tunnel *tunnel64_handlers;
  19 static DEFINE_MUTEX(tunnel4_mutex);
  20
  21 static inline struct xfrm_tunnel **fam_handlers(unsigned short family)
  22 {
  23         return (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
  24 }
  25
  26 int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
  27 {
  28         struct xfrm_tunnel **pprev;
  29         int ret = -EEXIST;
  30         int priority = handler->priority;
  31
  32         mutex_lock(&tunnel4_mutex);
  33
  34         for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
  35                 if ((*pprev)->priority > priority)
  36                         break;
  37                 if ((*pprev)->priority == priority)
  38                         goto err;
  39         }
  40
  41         handler->next = *pprev;
  42         *pprev = handler;
  43
  44         ret = 0;
  45
  46 err:
  47         mutex_unlock(&tunnel4_mutex);
  48
  49         return ret;
  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 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
  75
  76 static int tunnel4_rcv(struct sk_buff *skb)
  77 {
  78         struct xfrm_tunnel *handler;
  79
  80         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
  81                 goto drop;
  82
  83         for (handler = tunnel4_handlers; handler; handler = handler->next)
  84                 if (!handler->handler(skb))
  85                         return 0;
  86
  87         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
  88
  89 drop:
  90         kfree_skb(skb);
  91         return 0;
  92 }
  93
  94 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  95 static int tunnel64_rcv(struct sk_buff *skb)
  96 {
  97         struct xfrm_tunnel *handler;
  98
  99         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 100                 goto drop;
 101
 102         for (handler = tunnel64_handlers; handler; handler = handler->next)
 103                 if (!handler->handler(skb))
 104                         return 0;
 105
 106         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 107
 108 drop:
 109         kfree_skb(skb);
 110         return 0;
 111 }
 112 #endif
 113
 114 static void tunnel4_err(struct sk_buff *skb, u32 info)
 115 {
 116         struct xfrm_tunnel *handler;
 117
 118         for (handler = tunnel4_handlers; handler; handler = handler->next)
 119                 if (!handler->err_handler(skb, info))
 120                         break;
 121 }
 122
 123 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 124 static void tunnel64_err(struct sk_buff *skb, u32 info)
 125 {
 126         struct xfrm_tunnel *handler;
 127
 128         for (handler = tunnel64_handlers; handler; handler = handler->next)
 129                 if (!handler->err_handler(skb, info))
 130                         break;
 131 }
 132 #endif
 133
 134 static const struct net_protocol tunnel4_protocol = {
 135         .handler        =       tunnel4_rcv,
 136         .err_handler    =       tunnel4_err,
 137         .no_policy      =       1,
 138         .netns_ok       =       1,
 139 };
 140
 141 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 142 static const struct net_protocol tunnel64_protocol = {
 143         .handler        =       tunnel64_rcv,
 144         .err_handler    =       tunnel64_err,
 145         .no_policy      =       1,
 146         .netns_ok       =       1,
 147 };
 148 #endif
 149
 150 static int __init tunnel4_init(void)
 151 {
 152         if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
 153                 printk(KERN_ERR "tunnel4 init: can't add protocol\n");
 154                 return -EAGAIN;
 155         }
 156 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 157         if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
 158                 printk(KERN_ERR "tunnel64 init: can't add protocol\n");
 159                 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
 160                 return -EAGAIN;
 161         }
 162 #endif
 163         return 0;
 164 }
 165
 166 static void __exit tunnel4_fini(void)
 167 {
 168 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 169         if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
 170                 printk(KERN_ERR "tunnel64 close: can't remove protocol\n");
 171 #endif
 172         if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
 173                 printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
 174 }
 175
 176 module_init(tunnel4_init);
 177 module_exit(tunnel4_fini);
 178 MODULE_LICENSE("GPL");