[INET]: Introduce tunnel4/tunnel6
[linux-2.6.git] / 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 <net/protocol.h>
12 #include <net/xfrm.h>
13
14 static struct xfrm_tunnel *tunnel4_handlers;
15 static DEFINE_MUTEX(tunnel4_mutex);
16
17 int xfrm4_tunnel_register(struct xfrm_tunnel *handler)
18 {
19         struct xfrm_tunnel **pprev;
20         int ret = -EEXIST;
21         int priority = handler->priority;
22
23         mutex_lock(&tunnel4_mutex);
24
25         for (pprev = &tunnel4_handlers; *pprev; pprev = &(*pprev)->next) {
26                 if ((*pprev)->priority > priority)
27                         break;
28                 if ((*pprev)->priority == priority)
29                         goto err;
30         }
31
32         handler->next = *pprev;
33         *pprev = handler;
34
35         ret = 0;
36
37 err:
38         mutex_unlock(&tunnel4_mutex);
39
40         return ret;
41 }
42
43 EXPORT_SYMBOL(xfrm4_tunnel_register);
44
45 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler)
46 {
47         struct xfrm_tunnel **pprev;
48         int ret = -ENOENT;
49
50         mutex_lock(&tunnel4_mutex);
51
52         for (pprev = &tunnel4_handlers; *pprev; pprev = &(*pprev)->next) {
53                 if (*pprev == handler) {
54                         *pprev = handler->next;
55                         ret = 0;
56                         break;
57                 }
58         }
59
60         mutex_unlock(&tunnel4_mutex);
61
62         synchronize_net();
63
64         return ret;
65 }
66
67 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
68
69 static int tunnel4_rcv(struct sk_buff *skb)
70 {
71         struct xfrm_tunnel *handler;
72
73         for (handler = tunnel4_handlers; handler; handler = handler->next)
74                 if (!handler->handler(skb))
75                         return 0;
76
77         kfree_skb(skb);
78         return 0;
79 }
80
81 static void tunnel4_err(struct sk_buff *skb, u32 info)
82 {
83         struct xfrm_tunnel *handler;
84
85         for (handler = tunnel4_handlers; handler; handler = handler->next)
86                 if (!handler->err_handler(skb, info))
87                         break;
88 }
89
90 static struct net_protocol tunnel4_protocol = {
91         .handler        =       tunnel4_rcv,
92         .err_handler    =       tunnel4_err,
93         .no_policy      =       1,
94 };
95
96 static int __init tunnel4_init(void)
97 {
98         if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
99                 printk(KERN_ERR "tunnel4 init: can't add protocol\n");
100                 return -EAGAIN;
101         }
102         return 0;
103 }
104
105 static void __exit tunnel4_fini(void)
106 {
107         if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
108                 printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
109 }
110
111 module_init(tunnel4_init);
112 module_exit(tunnel4_fini);
113 MODULE_LICENSE("GPL");