1 // SPDX-License-Identifier: GPL-2.0-only
2 /* tunnel4.c: Generic IP tunnel transformer.
3 *
4 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
5 */
6
7 #include <linux/init.h>
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/mpls.h>
11 #include <linux/netdevice.h>
12 #include <linux/skbuff.h>
13 #include <linux/slab.h>
14 #include <net/icmp.h>
15 #include <net/ip.h>
16 #include <net/protocol.h>
17 #include <net/xfrm.h>
18
19 static struct xfrm_tunnel __rcu *tunnel4_handlers __read_mostly;
20 static struct xfrm_tunnel __rcu *tunnel64_handlers __read_mostly;
21 static struct xfrm_tunnel __rcu *tunnelmpls4_handlers __read_mostly;
22 static DEFINE_MUTEX(tunnel4_mutex);
23
fam_handlers(unsigned short family)24 static inline struct xfrm_tunnel __rcu **fam_handlers(unsigned short family)
25 {
26 return (family == AF_INET) ? &tunnel4_handlers :
27 (family == AF_INET6) ? &tunnel64_handlers :
28 &tunnelmpls4_handlers;
29 }
30
xfrm4_tunnel_register(struct xfrm_tunnel * handler,unsigned short family)31 int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
32 {
33 struct xfrm_tunnel __rcu **pprev;
34 struct xfrm_tunnel *t;
35
36 int ret = -EEXIST;
37 int priority = handler->priority;
38
39 mutex_lock(&tunnel4_mutex);
40
41 for (pprev = fam_handlers(family);
42 (t = rcu_dereference_protected(*pprev,
43 lockdep_is_held(&tunnel4_mutex))) != NULL;
44 pprev = &t->next) {
45 if (t->priority > priority)
46 break;
47 if (t->priority == priority)
48 goto err;
49 }
50
51 handler->next = *pprev;
52 rcu_assign_pointer(*pprev, handler);
53
54 ret = 0;
55
56 err:
57 mutex_unlock(&tunnel4_mutex);
58
59 return ret;
60 }
61 EXPORT_SYMBOL(xfrm4_tunnel_register);
62
xfrm4_tunnel_deregister(struct xfrm_tunnel * handler,unsigned short family)63 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
64 {
65 struct xfrm_tunnel __rcu **pprev;
66 struct xfrm_tunnel *t;
67 int ret = -ENOENT;
68
69 mutex_lock(&tunnel4_mutex);
70
71 for (pprev = fam_handlers(family);
72 (t = rcu_dereference_protected(*pprev,
73 lockdep_is_held(&tunnel4_mutex))) != NULL;
74 pprev = &t->next) {
75 if (t == handler) {
76 *pprev = handler->next;
77 ret = 0;
78 break;
79 }
80 }
81
82 mutex_unlock(&tunnel4_mutex);
83
84 synchronize_net();
85
86 return ret;
87 }
88 EXPORT_SYMBOL(xfrm4_tunnel_deregister);
89
90 #define for_each_tunnel_rcu(head, handler) \
91 for (handler = rcu_dereference(head); \
92 handler != NULL; \
93 handler = rcu_dereference(handler->next)) \
94
tunnel4_rcv(struct sk_buff * skb)95 static int tunnel4_rcv(struct sk_buff *skb)
96 {
97 struct xfrm_tunnel *handler;
98
99 if (!pskb_may_pull(skb, sizeof(struct iphdr)))
100 goto drop;
101
102 for_each_tunnel_rcu(tunnel4_handlers, handler)
103 if (!handler->handler(skb))
104 return 0;
105
106 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
107
108 drop:
109 kfree_skb(skb);
110 return 0;
111 }
112
113 #if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
tunnel4_rcv_cb(struct sk_buff * skb,u8 proto,int err)114 static int tunnel4_rcv_cb(struct sk_buff *skb, u8 proto, int err)
115 {
116 struct xfrm_tunnel __rcu *head;
117 struct xfrm_tunnel *handler;
118 int ret;
119
120 head = (proto == IPPROTO_IPIP) ? tunnel4_handlers : tunnel64_handlers;
121
122 for_each_tunnel_rcu(head, handler) {
123 if (handler->cb_handler) {
124 ret = handler->cb_handler(skb, err);
125 if (ret <= 0)
126 return ret;
127 }
128 }
129
130 return 0;
131 }
132
133 static const struct xfrm_input_afinfo tunnel4_input_afinfo = {
134 .family = AF_INET,
135 .is_ipip = true,
136 .callback = tunnel4_rcv_cb,
137 };
138 #endif
139
140 #if IS_ENABLED(CONFIG_IPV6)
tunnel64_rcv(struct sk_buff * skb)141 static int tunnel64_rcv(struct sk_buff *skb)
142 {
143 struct xfrm_tunnel *handler;
144
145 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
146 goto drop;
147
148 for_each_tunnel_rcu(tunnel64_handlers, handler)
149 if (!handler->handler(skb))
150 return 0;
151
152 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
153
154 drop:
155 kfree_skb(skb);
156 return 0;
157 }
158 #endif
159
160 #if IS_ENABLED(CONFIG_MPLS)
tunnelmpls4_rcv(struct sk_buff * skb)161 static int tunnelmpls4_rcv(struct sk_buff *skb)
162 {
163 struct xfrm_tunnel *handler;
164
165 if (!pskb_may_pull(skb, sizeof(struct mpls_label)))
166 goto drop;
167
168 for_each_tunnel_rcu(tunnelmpls4_handlers, handler)
169 if (!handler->handler(skb))
170 return 0;
171
172 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
173
174 drop:
175 kfree_skb(skb);
176 return 0;
177 }
178 #endif
179
tunnel4_err(struct sk_buff * skb,u32 info)180 static int tunnel4_err(struct sk_buff *skb, u32 info)
181 {
182 struct xfrm_tunnel *handler;
183
184 for_each_tunnel_rcu(tunnel4_handlers, handler)
185 if (!handler->err_handler(skb, info))
186 return 0;
187
188 return -ENOENT;
189 }
190
191 #if IS_ENABLED(CONFIG_IPV6)
tunnel64_err(struct sk_buff * skb,u32 info)192 static int tunnel64_err(struct sk_buff *skb, u32 info)
193 {
194 struct xfrm_tunnel *handler;
195
196 for_each_tunnel_rcu(tunnel64_handlers, handler)
197 if (!handler->err_handler(skb, info))
198 return 0;
199
200 return -ENOENT;
201 }
202 #endif
203
204 #if IS_ENABLED(CONFIG_MPLS)
tunnelmpls4_err(struct sk_buff * skb,u32 info)205 static int tunnelmpls4_err(struct sk_buff *skb, u32 info)
206 {
207 struct xfrm_tunnel *handler;
208
209 for_each_tunnel_rcu(tunnelmpls4_handlers, handler)
210 if (!handler->err_handler(skb, info))
211 return 0;
212
213 return -ENOENT;
214 }
215 #endif
216
217 static const struct net_protocol tunnel4_protocol = {
218 .handler = tunnel4_rcv,
219 .err_handler = tunnel4_err,
220 .no_policy = 1,
221 .netns_ok = 1,
222 };
223
224 #if IS_ENABLED(CONFIG_IPV6)
225 static const struct net_protocol tunnel64_protocol = {
226 .handler = tunnel64_rcv,
227 .err_handler = tunnel64_err,
228 .no_policy = 1,
229 .netns_ok = 1,
230 };
231 #endif
232
233 #if IS_ENABLED(CONFIG_MPLS)
234 static const struct net_protocol tunnelmpls4_protocol = {
235 .handler = tunnelmpls4_rcv,
236 .err_handler = tunnelmpls4_err,
237 .no_policy = 1,
238 .netns_ok = 1,
239 };
240 #endif
241
tunnel4_init(void)242 static int __init tunnel4_init(void)
243 {
244 if (inet_add_protocol(&tunnel4_protocol, IPPROTO_IPIP))
245 goto err;
246 #if IS_ENABLED(CONFIG_IPV6)
247 if (inet_add_protocol(&tunnel64_protocol, IPPROTO_IPV6)) {
248 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
249 goto err;
250 }
251 #endif
252 #if IS_ENABLED(CONFIG_MPLS)
253 if (inet_add_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS)) {
254 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
255 #if IS_ENABLED(CONFIG_IPV6)
256 inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6);
257 #endif
258 goto err;
259 }
260 #endif
261 #if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
262 if (xfrm_input_register_afinfo(&tunnel4_input_afinfo)) {
263 inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP);
264 #if IS_ENABLED(CONFIG_IPV6)
265 inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6);
266 #endif
267 #if IS_ENABLED(CONFIG_MPLS)
268 inet_del_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS);
269 #endif
270 goto err;
271 }
272 #endif
273 return 0;
274
275 err:
276 pr_err("%s: can't add protocol\n", __func__);
277 return -EAGAIN;
278 }
279
tunnel4_fini(void)280 static void __exit tunnel4_fini(void)
281 {
282 #if IS_ENABLED(CONFIG_INET_XFRM_TUNNEL)
283 if (xfrm_input_unregister_afinfo(&tunnel4_input_afinfo))
284 pr_err("tunnel4 close: can't remove input afinfo\n");
285 #endif
286 #if IS_ENABLED(CONFIG_MPLS)
287 if (inet_del_protocol(&tunnelmpls4_protocol, IPPROTO_MPLS))
288 pr_err("tunnelmpls4 close: can't remove protocol\n");
289 #endif
290 #if IS_ENABLED(CONFIG_IPV6)
291 if (inet_del_protocol(&tunnel64_protocol, IPPROTO_IPV6))
292 pr_err("tunnel64 close: can't remove protocol\n");
293 #endif
294 if (inet_del_protocol(&tunnel4_protocol, IPPROTO_IPIP))
295 pr_err("tunnel4 close: can't remove protocol\n");
296 }
297
298 module_init(tunnel4_init);
299 module_exit(tunnel4_fini);
300 MODULE_LICENSE("GPL");
301