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 
22 static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
23 static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
24 static struct xfrm6_tunnel __rcu *tunnelmpls6_handlers __read_mostly;
25 static DEFINE_MUTEX(tunnel6_mutex);
26 
xfrm6_tunnel_mpls_supported(void)27 static inline int xfrm6_tunnel_mpls_supported(void)
28 {
29 	return IS_ENABLED(CONFIG_MPLS);
30 }
31 
xfrm6_tunnel_register(struct xfrm6_tunnel * handler,unsigned short family)32 int 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 
69 err:
70 	mutex_unlock(&tunnel6_mutex);
71 
72 	return ret;
73 }
74 EXPORT_SYMBOL(xfrm6_tunnel_register);
75 
xfrm6_tunnel_deregister(struct xfrm6_tunnel * handler,unsigned short family)76 int 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 
108 err:
109 	mutex_unlock(&tunnel6_mutex);
110 
111 	synchronize_net();
112 
113 	return ret;
114 }
115 EXPORT_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 
tunnelmpls6_rcv(struct sk_buff * skb)122 static 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 
135 drop:
136 	kfree_skb(skb);
137 	return 0;
138 }
139 
tunnel6_rcv(struct sk_buff * skb)140 static 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 
153 drop:
154 	kfree_skb(skb);
155 	return 0;
156 }
157 
158 #if IS_ENABLED(CONFIG_INET6_XFRM_TUNNEL)
tunnel6_rcv_cb(struct sk_buff * skb,u8 proto,int err)159 static 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 
178 static 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 
tunnel46_rcv(struct sk_buff * skb)185 static 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 
198 drop:
199 	kfree_skb(skb);
200 	return 0;
201 }
202 
tunnel6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)203 static 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 
tunnel46_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)215 static 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 
tunnelmpls6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)227 static 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 
239 static 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 
245 static 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 
251 static 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 
tunnel6_init(void)257 static 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 
tunnel6_fini(void)288 static 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 
303 module_init(tunnel6_init);
304 module_exit(tunnel6_fini);
305 MODULE_LICENSE("GPL");
306