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
16static struct xfrm_tunnel *tunnel4_handlers;
17static struct xfrm_tunnel *tunnel64_handlers;
18static DEFINE_MUTEX(tunnel4_mutex);
19
20int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
21{
22	struct xfrm_tunnel **pprev;
23	int ret = -EEXIST;
24	int priority = handler->priority;
25
26	mutex_lock(&tunnel4_mutex);
27
28	for (pprev = (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
29	     *pprev; pprev = &(*pprev)->next) {
30		if ((*pprev)->priority > priority)
31			break;
32		if ((*pprev)->priority == priority)
33			goto err;
34	}
35
36	handler->next = *pprev;
37	*pprev = handler;
38
39	ret = 0;
40
41err:
42	mutex_unlock(&tunnel4_mutex);
43
44	return ret;
45}
46
47EXPORT_SYMBOL(xfrm4_tunnel_register);
48
49int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
50{
51	struct xfrm_tunnel **pprev;
52	int ret = -ENOENT;
53
54	mutex_lock(&tunnel4_mutex);
55
56	for (pprev = (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
57	     *pprev; pprev = &(*pprev)->next) {
58		if (*pprev == handler) {
59			*pprev = handler->next;
60			ret = 0;
61			break;
62		}
63	}
64
65	mutex_unlock(&tunnel4_mutex);
66
67	synchronize_net();
68
69	return ret;
70}
71
72EXPORT_SYMBOL(xfrm4_tunnel_deregister);
73
74static int tunnel4_rcv(struct sk_buff *skb)
75{
76	struct xfrm_tunnel *handler;
77
78	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
79		goto drop;
80
81	for (handler = tunnel4_handlers; handler; handler = handler->next)
82		if (!handler->handler(skb))
83			return 0;
84
85	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
86
87drop:
88	kfree_skb(skb);
89	return 0;
90}
91
92#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
93static int tunnel64_rcv(struct sk_buff *skb)
94{
95	struct xfrm_tunnel *handler;
96
97	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
98		goto drop;
99
100	for (handler = tunnel64_handlers; handler; handler = handler->next)
101		if (!handler->handler(skb))
102			return 0;
103
104	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
105
106drop:
107	kfree_skb(skb);
108	return 0;
109}
110#endif
111
112static void tunnel4_err(struct sk_buff *skb, u32 info)
113{
114	struct xfrm_tunnel *handler;
115
116	for (handler = tunnel4_handlers; handler; handler = handler->next)
117		if (!handler->err_handler(skb, info))
118			break;
119}
120
121static struct net_protocol tunnel4_protocol = {
122	.handler	=	tunnel4_rcv,
123	.err_handler	=	tunnel4_err,
124	.no_policy	=	1,
125};
126
127#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
128static struct net_protocol tunnel64_protocol = {
129	.handler	=	tunnel64_rcv,
130	.err_handler	=	tunnel4_err,
131	.no_policy	=	1,
132};
133#endif
134
135static int __init tunnel4_init(void)
136{
137	if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP)) {
138		printk(KERN_ERR "tunnel4 init: can't add protocol\n");
139		return -EAGAIN;
140	}
141#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
142	if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
143		printk(KERN_ERR "tunnel64 init: can't add protocol\n");
144		inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
145		return -EAGAIN;
146	}
147#endif
148	return 0;
149}
150
151static void __exit tunnel4_fini(void)
152{
153#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
154	if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
155		printk(KERN_ERR "tunnel64 close: can't remove protocol\n");
156#endif
157	if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
158		printk(KERN_ERR "tunnel4 close: can't remove protocol\n");
159}
160
161module_init(tunnel4_init);
162module_exit(tunnel4_fini);
163MODULE_LICENSE("GPL");
164