net/ipv4/xfrm4_tunnel.c

   1 /* xfrm4_tunnel.c: Generic IP tunnel transformer.
   2  *
   3  * Copyright (C) 2003 David S. Miller (davem@redhat.com)
   4  */
   5
   6 #include <linux/skbuff.h>
   7 #include <linux/module.h>
   8 #include <net/xfrm.h>
   9 #include <net/ip.h>
  10 #include <net/protocol.h>
  11
  12 static int ipip_output(struct xfrm_state *x, struct sk_buff *skb)
  13 {
  14         struct iphdr *iph;
  15
  16         iph = skb->nh.iph;
  17         iph->tot_len = htons(skb->len);
  18         ip_send_check(iph);
  19
  20         return 0;
  21 }
  22
  23 static int ipip_xfrm_rcv(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
  24 {
  25         return 0;
  26 }
  27
  28 static struct xfrm_tunnel *ipip_handler;
  29 static DECLARE_MUTEX(xfrm4_tunnel_sem);
  30
  31 int xfrm4_tunnel_register(struct xfrm_tunnel *handler)
  32 {
  33         int ret;
  34
  35         down(&xfrm4_tunnel_sem);
  36         ret = 0;
  37         if (ipip_handler != NULL)
  38                 ret = -EINVAL;
  39         if (!ret)
  40                 ipip_handler = handler;
  41         up(&xfrm4_tunnel_sem);
  42
  43         return ret;
  44 }
  45
  46 EXPORT_SYMBOL(xfrm4_tunnel_register);
  47
  48 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler)
  49 {
  50         int ret;
  51
  52         down(&xfrm4_tunnel_sem);
  53         ret = 0;
  54         if (ipip_handler != handler)
  55                 ret = -EINVAL;
  56         if (!ret)
  57                 ipip_handler = NULL;
  58         up(&xfrm4_tunnel_sem);
  59
  60         synchronize_net();
  61
  62         return ret;
  63 }
  64
  65 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
  66
  67 static int ipip_rcv(struct sk_buff *skb)
  68 {
  69         struct xfrm_tunnel *handler = ipip_handler;
  70
  71         /* Tunnel devices take precedence.  */
  72         if (handler && handler->handler(skb) == 0)
  73                 return 0;
  74
  75         return xfrm4_rcv(skb);
  76 }
  77
  78 static void ipip_err(struct sk_buff *skb, u32 info)
  79 {
  80         struct xfrm_tunnel *handler = ipip_handler;
  81
  82         if (handler)
  83                 handler->err_handler(skb, info);
  84 }
  85
  86 static int ipip_init_state(struct xfrm_state *x)
  87 {
  88         if (!x->props.mode)
  89                 return -EINVAL;
  90
  91         if (x->encap)
  92                 return -EINVAL;
  93
  94         x->props.header_len = sizeof(struct iphdr);
  95
  96         return 0;
  97 }
  98
  99 static void ipip_destroy(struct xfrm_state *x)
 100 {
 101 }
 102
 103 static struct xfrm_type ipip_type = {
 104         .description    = "IPIP",
 105         .owner          = THIS_MODULE,
 106         .proto          = IPPROTO_IPIP,
 107         .init_state     = ipip_init_state,
 108         .destructor     = ipip_destroy,
 109         .input          = ipip_xfrm_rcv,
 110         .output         = ipip_output
 111 };
 112
 113 static struct net_protocol ipip_protocol = {
 114         .handler        =       ipip_rcv,
 115         .err_handler    =       ipip_err,
 116         .no_policy      =       1,
 117 };
 118
 119 static int __init ipip_init(void)
 120 {
 121         if (xfrm_register_type(&ipip_type, AF_INET) < 0) {
 122                 printk(KERN_INFO "ipip init: can't add xfrm type\n");
 123                 return -EAGAIN;
 124         }
 125         if (inet_add_protocol(&ipip_protocol, IPPROTO_IPIP) < 0) {
 126                 printk(KERN_INFO "ipip init: can't add protocol\n");
 127                 xfrm_unregister_type(&ipip_type, AF_INET);
 128                 return -EAGAIN;
 129         }
 130         return 0;
 131 }
 132
 133 static void __exit ipip_fini(void)
 134 {
 135         if (inet_del_protocol(&ipip_protocol, IPPROTO_IPIP) < 0)
 136                 printk(KERN_INFO "ipip close: can't remove protocol\n");
 137         if (xfrm_unregister_type(&ipip_type, AF_INET) < 0)
 138                 printk(KERN_INFO "ipip close: can't remove xfrm type\n");
 139 }
 140
 141 module_init(ipip_init);
 142 module_exit(ipip_fini);
 143 MODULE_LICENSE("GPL");