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 __read_mostly;
  18 static struct xfrm_tunnel *tunnel64_handlers __read_mostly;
  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         rcu_assign_pointer(*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 #define for_each_tunnel_rcu(head, handler)              \
  77         for (handler = rcu_dereference(head);           \
  78              handler != NULL;                           \
  79              handler = rcu_dereference(handler->next))  \
  80
  81 static int tunnel4_rcv(struct sk_buff *skb)
  82 {
  83         struct xfrm_tunnel *handler;
  84
  85         if (!pskb_may_pull(skb, sizeof(struct iphdr)))
  86                 goto drop;
  87
  88         for_each_tunnel_rcu(tunnel4_handlers, handler)
  89                 if (!handler->handler(skb))
  90                         return 0;
  91
  92         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
  93
  94 drop:
  95         kfree_skb(skb);
  96         return 0;
  97 }
  98
  99 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 100 static int tunnel64_rcv(struct sk_buff *skb)
 101 {
 102         struct xfrm_tunnel *handler;
 103
 104         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 105                 goto drop;
 106
 107         for_each_tunnel_rcu(tunnel64_handlers, handler)
 108                 if (!handler->handler(skb))
 109                         return 0;
 110
 111         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 112
 113 drop:
 114         kfree_skb(skb);
 115         return 0;
 116 }
 117 #endif
 118
 119 static void tunnel4_err(struct sk_buff *skb, u32 info)
 120 {
 121         struct xfrm_tunnel *handler;
 122
 123         for_each_tunnel_rcu(tunnel4_handlers, handler)
 124                 if (!handler->err_handler(skb, info))
 125                         break;
 126 }
 127
 128 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 129 static void tunnel64_err(struct sk_buff *skb, u32 info)
 130 {
 131         struct xfrm_tunnel *handler;
 132
 133         for_each_tunnel_rcu(tunnel64_handlers, handler)
 134                 if (!handler->err_handler(skb, info))
 135                         break;
 136 }
 137 #endif
 138
 139 static const struct net_protocol tunnel4_protocol = {
 140         .handler        =       tunnel4_rcv,
 141         .err_handler    =       tunnel4_err,
 142         .no_policy      =       1,
 143         .netns_ok       =       1,
 144 };
 145
 146 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 147 static const struct net_protocol tunnel64_protocol = {
 148         .handler        =       tunnel64_rcv,
 149         .err_handler    =       tunnel64_err,
 150         .no_policy      =       1,
 151         .netns_ok       =       1,
 152 };
 153 #endif
 154
 155 static int __init tunnel4_init(void)
 156 {
 157         if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
 158                 printk(KERN_ERR "tunnel4 init: can't add protocol\n");
 159                 return -EAGAIN;
 160         }
 161 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 162         if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
 163                 printk(KERN_ERR "tunnel64 init: can't add protocol\n");
 164                 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
 165                 return -EAGAIN;
 166         }
 167 #endif
 168         return 0;
 169 }
 170
 171 static void __exit tunnel4_fini(void)
 172 {
 173 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 174         if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
 175                 printk(KERN_ERR "tunnel64 close: can't remove protocol\n");
 176 #endif
 177         if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
 178                 printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
 179 }
 180
 181 module_init(tunnel4_init);
 182 module_exit(tunnel4_fini);
 183 MODULE_LICENSE("GPL");