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
27 static inline int xfrm6_tunnel_mpls_supported(void)
28 {
29 return IS_ENABLED(CONFIG_MPLS);
30 }
31
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
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
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
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)
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
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
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
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
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
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
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
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