1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C)2003,2004 USAGI/WIDE Project
4 *
5 * Authors	Mitsuru KANDA  <mk@linux-ipv6.org>
6 *		YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
7 */
8
9#define pr_fmt(fmt) "IPv6: " fmt
10
11#include <linux/icmpv6.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/mutex.h>
15#include <linux/netdevice.h>
16#include <linux/skbuff.h>
17#include <linux/slab.h>
18#include <net/ipv6.h>
19#include <net/protocol.h>
20#include <net/xfrm.h>
21
22static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
23static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
24static struct xfrm6_tunnel __rcu *tunnelmpls6_handlers __read_mostly;
25static DEFINE_MUTEX(tunnel6_mutex);
26
27static inline int xfrm6_tunnel_mpls_supported(void)
28{
29	return IS_ENABLED(CONFIG_MPLS);
30}
31
32int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
33{
34	struct xfrm6_tunnel __rcu **pprev;
35	struct xfrm6_tunnel *t;
36	int ret = -EEXIST;
37	int priority = handler->priority;
38
39	mutex_lock(&tunnel6_mutex);
40
41	switch (family) {
42	case AF_INET6:
43		pprev = &tunnel6_handlers;
44		break;
45	case AF_INET:
46		pprev = &tunnel46_handlers;
47		break;
48	case AF_MPLS:
49		pprev = &tunnelmpls6_handlers;
50		break;
51	default:
52		goto err;
53	}
54
55	for (; (t = rcu_dereference_protected(*pprev,
56			lockdep_is_held(&tunnel6_mutex))) != NULL;
57	     pprev = &t->next) {
58		if (t->priority > priority)
59			break;
60		if (t->priority == priority)
61			goto err;
62	}
63
64	handler->next = *pprev;
65	rcu_assign_pointer(*pprev, handler);
66
67	ret = 0;
68
69err:
70	mutex_unlock(&tunnel6_mutex);
71
72	return ret;
73}
74EXPORT_SYMBOL(xfrm6_tunnel_register);
75
76int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
77{
78	struct xfrm6_tunnel __rcu **pprev;
79	struct xfrm6_tunnel *t;
80	int ret = -ENOENT;
81
82	mutex_lock(&tunnel6_mutex);
83
84	switch (family) {
85	case AF_INET6:
86		pprev = &tunnel6_handlers;
87		break;
88	case AF_INET:
89		pprev = &tunnel46_handlers;
90		break;
91	case AF_MPLS:
92		pprev = &tunnelmpls6_handlers;
93		break;
94	default:
95		goto err;
96	}
97
98	for (; (t = rcu_dereference_protected(*pprev,
99			lockdep_is_held(&tunnel6_mutex))) != NULL;
100	     pprev = &t->next) {
101		if (t == handler) {
102			*pprev = handler->next;
103			ret = 0;
104			break;
105		}
106	}
107
108err:
109	mutex_unlock(&tunnel6_mutex);
110
111	synchronize_net();
112
113	return ret;
114}
115EXPORT_SYMBOL(xfrm6_tunnel_deregister);
116
117#define for_each_tunnel_rcu(head, handler)		\
118	for (handler = rcu_dereference(head);		\
119	     handler != NULL;				\
120	     handler = rcu_dereference(handler->next))	\
121
122static int tunnelmpls6_rcv(struct sk_buff *skb)
123{
124	struct xfrm6_tunnel *handler;
125
126	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
127		goto drop;
128
129	for_each_tunnel_rcu(tunnelmpls6_handlers, handler)
130		if (!handler->handler(skb))
131			return 0;
132
133	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
134
135drop:
136	kfree_skb(skb);
137	return 0;
138}
139
140static int tunnel6_rcv(struct sk_buff *skb)
141{
142	struct xfrm6_tunnel *handler;
143
144	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
145		goto drop;
146
147	for_each_tunnel_rcu(tunnel6_handlers, handler)
148		if (!handler->handler(skb))
149			return 0;
150
151	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
152
153drop:
154	kfree_skb(skb);
155	return 0;
156}
157
158#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
159static int tunnel6_rcv_cb(struct sk_buff *skb, u8 proto, int err)
160{
161	struct xfrm6_tunnel __rcu *head;
162	struct xfrm6_tunnel *handler;
163	int ret;
164
165	head = (proto == IPPROTO_IPV6) ? tunnel6_handlers : tunnel46_handlers;
166
167	for_each_tunnel_rcu(head, handler) {
168		if (handler->cb_handler) {
169			ret = handler->cb_handler(skb, err);
170			if (ret <= 0)
171				return ret;
172		}
173	}
174
175	return 0;
176}
177
178static const struct xfrm_input_afinfo tunnel6_input_afinfo = {
179	.family		=	AF_INET6,
180	.is_ipip	=	true,
181	.callback	=	tunnel6_rcv_cb,
182};
183#endif
184
185static int tunnel46_rcv(struct sk_buff *skb)
186{
187	struct xfrm6_tunnel *handler;
188
189	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
190		goto drop;
191
192	for_each_tunnel_rcu(tunnel46_handlers, handler)
193		if (!handler->handler(skb))
194			return 0;
195
196	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
197
198drop:
199	kfree_skb(skb);
200	return 0;
201}
202
203static int tunnel6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
204			u8 type, u8 code, int offset, __be32 info)
205{
206	struct xfrm6_tunnel *handler;
207
208	for_each_tunnel_rcu(tunnel6_handlers, handler)
209		if (!handler->err_handler(skb, opt, type, code, offset, info))
210			return 0;
211
212	return -ENOENT;
213}
214
215static int tunnel46_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
216			 u8 type, u8 code, int offset, __be32 info)
217{
218	struct xfrm6_tunnel *handler;
219
220	for_each_tunnel_rcu(tunnel46_handlers, handler)
221		if (!handler->err_handler(skb, opt, type, code, offset, info))
222			return 0;
223
224	return -ENOENT;
225}
226
227static int tunnelmpls6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
228			   u8 type, u8 code, int offset, __be32 info)
229{
230	struct xfrm6_tunnel *handler;
231
232	for_each_tunnel_rcu(tunnelmpls6_handlers, handler)
233		if (!handler->err_handler(skb, opt, type, code, offset, info))
234			return 0;
235
236	return -ENOENT;
237}
238
239static const struct inet6_protocol tunnel6_protocol = {
240	.handler	= tunnel6_rcv,
241	.err_handler	= tunnel6_err,
242	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
243};
244
245static const struct inet6_protocol tunnel46_protocol = {
246	.handler	= tunnel46_rcv,
247	.err_handler	= tunnel46_err,
248	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
249};
250
251static const struct inet6_protocol tunnelmpls6_protocol = {
252	.handler	= tunnelmpls6_rcv,
253	.err_handler	= tunnelmpls6_err,
254	.flags          = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
255};
256
257static int __init tunnel6_init(void)
258{
259	if (inet6_add_protocol(&tunnel6_protocol, IPPROTO_IPV6)) {
260		pr_err("%s: can't add protocol\n", __func__);
261		return -EAGAIN;
262	}
263	if (inet6_add_protocol(&tunnel46_protocol, IPPROTO_IPIP)) {
264		pr_err("%s: can't add protocol\n", __func__);
265		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
266		return -EAGAIN;
267	}
268	if (xfrm6_tunnel_mpls_supported() &&
269	    inet6_add_protocol(&tunnelmpls6_protocol, IPPROTO_MPLS)) {
270		pr_err("%s: can't add protocol\n", __func__);
271		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
272		inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP);
273		return -EAGAIN;
274	}
275#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
276	if (xfrm_input_register_afinfo(&tunnel6_input_afinfo)) {
277		pr_err("%s: can't add input afinfo\n", __func__);
278		inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6);
279		inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP);
280		if (xfrm6_tunnel_mpls_supported())
281			inet6_del_protocol(&tunnelmpls6_protocol, IPPROTO_MPLS);
282		return -EAGAIN;
283	}
284#endif
285	return 0;
286}
287
288static void __exit tunnel6_fini(void)
289{
290#if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
291	if (xfrm_input_unregister_afinfo(&tunnel6_input_afinfo))
292		pr_err("%s: can't remove input afinfo\n", __func__);
293#endif
294	if (inet6_del_protocol(&tunnel46_protocol, IPPROTO_IPIP))
295		pr_err("%s: can't remove protocol\n", __func__);
296	if (inet6_del_protocol(&tunnel6_protocol, IPPROTO_IPV6))
297		pr_err("%s: can't remove protocol\n", __func__);
298	if (xfrm6_tunnel_mpls_supported() &&
299	    inet6_del_protocol(&tunnelmpls6_protocol, IPPROTO_MPLS))
300		pr_err("%s: can't remove protocol\n", __func__);
301}
302
303module_init(tunnel6_init);
304module_exit(tunnel6_fini);
305MODULE_DESCRIPTION("IP-in-IPv6 tunnel driver");
306MODULE_LICENSE("GPL");
307