1/*
2 * Copyright (C)2003,2004 USAGI/WIDE Project
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 *
17 * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
18 *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
19 */
20
21#define pr_fmt(fmt) "IPv6: " fmt
22
23#include <linux/icmpv6.h>
24#include <linux/init.h>
25#include <linux/module.h>
26#include <linux/mutex.h>
27#include <linux/netdevice.h>
28#include <linux/skbuff.h>
29#include <linux/slab.h>
30#include <net/ipv6.h>
31#include <net/protocol.h>
32#include <net/xfrm.h>
33
34static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
35static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
36static DEFINE_MUTEX(tunnel6_mutex);
37
38int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
39{
40	struct xfrm6_tunnel __rcu **pprev;
41	struct xfrm6_tunnel *t;
42	int ret = -EEXIST;
43	int priority = handler->priority;
44
45	mutex_lock(&tunnel6_mutex);
46
47	for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
48	     (t = rcu_dereference_protected(*pprev,
49			lockdep_is_held(&tunnel6_mutex))) != NULL;
50	     pprev = &t->next) {
51		if (t->priority > priority)
52			break;
53		if (t->priority == priority)
54			goto err;
55	}
56
57	handler->next = *pprev;
58	rcu_assign_pointer(*pprev, handler);
59
60	ret = 0;
61
62err:
63	mutex_unlock(&tunnel6_mutex);
64
65	return ret;
66}
67EXPORT_SYMBOL(xfrm6_tunnel_register);
68
69int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
70{
71	struct xfrm6_tunnel __rcu **pprev;
72	struct xfrm6_tunnel *t;
73	int ret = -ENOENT;
74
75	mutex_lock(&tunnel6_mutex);
76
77	for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
78	     (t = rcu_dereference_protected(*pprev,
79			lockdep_is_held(&tunnel6_mutex))) != NULL;
80	     pprev = &t->next) {
81		if (t == handler) {
82			*pprev = handler->next;
83			ret = 0;
84			break;
85		}
86	}
87
88	mutex_unlock(&tunnel6_mutex);
89
90	synchronize_net();
91
92	return ret;
93}
94EXPORT_SYMBOL(xfrm6_tunnel_deregister);
95
96#define for_each_tunnel_rcu(head, handler)		\
97	for (handler = rcu_dereference(head);		\
98	     handler != NULL;				\
99	     handler = rcu_dereference(handler->next))	\
100
101static int tunnel6_rcv(struct sk_buff *skb)
102{
103	struct xfrm6_tunnel *handler;
104
105	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
106		goto drop;
107
108	for_each_tunnel_rcu(tunnel6_handlers, handler)
109		if (!handler->handler(skb))
110			return 0;
111
112	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
113
114drop:
115	kfree_skb(skb);
116	return 0;
117}
118
119static int tunnel46_rcv(struct sk_buff *skb)
120{
121	struct xfrm6_tunnel *handler;
122
123	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
124		goto drop;
125
126	for_each_tunnel_rcu(tunnel46_handlers, handler)
127		if (!handler->handler(skb))
128			return 0;
129
130	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
131
132drop:
133	kfree_skb(skb);
134	return 0;
135}
136
137static void tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
138			u8 type, u8 code, int offset, __be32 info)
139{
140	struct xfrm6_tunnel *handler;
141
142	for_each_tunnel_rcu(tunnel6_handlers, handler)
143		if (!handler->err_handler(skb, opt, type, code, offset, info))
144			break;
145}
146
147static const struct inet6_protocol tunnel6_protocol = {
148	.handler	= tunnel6_rcv,
149	.err_handler	= tunnel6_err,
150	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
151};
152
153static const struct inet6_protocol tunnel46_protocol = {
154	.handler	= tunnel46_rcv,
155	.err_handler	= tunnel6_err,
156	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
157};
158
159static int __init tunnel6_init(void)
160{
161	if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
162		pr_err("%s: can't add protocol\n", __func__);
163		return -EAGAIN;
164	}
165	if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
166		pr_err("%s: can't add protocol\n", __func__);
167		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
168		return -EAGAIN;
169	}
170	return 0;
171}
172
173static void __exit tunnel6_fini(void)
174{
175	if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
176		pr_err("%s: can't remove protocol\n", __func__);
177	if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
178		pr_err("%s: can't remove protocol\n", __func__);
179}
180
181module_init(tunnel6_init);
182module_exit(tunnel6_fini);
183MODULE_LICENSE("GPL");
184