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1/*
2 * lwtunnel Infrastructure for light weight tunnels like mpls
3 *
4 * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 */
12
13#include <linux/capability.h>
14#include <linux/module.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/slab.h>
18#include <linux/uaccess.h>
19#include <linux/skbuff.h>
20#include <linux/netdevice.h>
21#include <linux/lwtunnel.h>
22#include <linux/in.h>
23#include <linux/init.h>
24#include <linux/err.h>
25
26#include <net/lwtunnel.h>
27#include <net/rtnetlink.h>
28#include <net/ip6_fib.h>
29
30#ifdef CONFIG_MODULES
31
32static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type)
33{
34 /* Only lwt encaps implemented without using an interface for
35 * the encap need to return a string here.
36 */
37 switch (encap_type) {
38 case LWTUNNEL_ENCAP_MPLS:
39 return "MPLS";
40 case LWTUNNEL_ENCAP_ILA:
41 return "ILA";
42 case LWTUNNEL_ENCAP_IP6:
43 case LWTUNNEL_ENCAP_IP:
44 case LWTUNNEL_ENCAP_NONE:
45 case __LWTUNNEL_ENCAP_MAX:
46 /* should not have got here */
47 WARN_ON(1);
48 break;
49 }
50 return NULL;
51}
52
53#endif /* CONFIG_MODULES */
54
55struct lwtunnel_state *lwtunnel_state_alloc(int encap_len)
56{
57 struct lwtunnel_state *lws;
58
59 lws = kzalloc(sizeof(*lws) + encap_len, GFP_ATOMIC);
60
61 return lws;
62}
63EXPORT_SYMBOL(lwtunnel_state_alloc);
64
65static const struct lwtunnel_encap_ops __rcu *
66 lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly;
67
68int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops,
69 unsigned int num)
70{
71 if (num > LWTUNNEL_ENCAP_MAX)
72 return -ERANGE;
73
74 return !cmpxchg((const struct lwtunnel_encap_ops **)
75 &lwtun_encaps[num],
76 NULL, ops) ? 0 : -1;
77}
78EXPORT_SYMBOL(lwtunnel_encap_add_ops);
79
80int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *ops,
81 unsigned int encap_type)
82{
83 int ret;
84
85 if (encap_type == LWTUNNEL_ENCAP_NONE ||
86 encap_type > LWTUNNEL_ENCAP_MAX)
87 return -ERANGE;
88
89 ret = (cmpxchg((const struct lwtunnel_encap_ops **)
90 &lwtun_encaps[encap_type],
91 ops, NULL) == ops) ? 0 : -1;
92
93 synchronize_net();
94
95 return ret;
96}
97EXPORT_SYMBOL(lwtunnel_encap_del_ops);
98
99int lwtunnel_build_state(struct net_device *dev, u16 encap_type,
100 struct nlattr *encap, unsigned int family,
101 const void *cfg, struct lwtunnel_state **lws)
102{
103 const struct lwtunnel_encap_ops *ops;
104 int ret = -EINVAL;
105
106 if (encap_type == LWTUNNEL_ENCAP_NONE ||
107 encap_type > LWTUNNEL_ENCAP_MAX)
108 return ret;
109
110 ret = -EOPNOTSUPP;
111 rcu_read_lock();
112 ops = rcu_dereference(lwtun_encaps[encap_type]);
113#ifdef CONFIG_MODULES
114 if (!ops) {
115 const char *encap_type_str = lwtunnel_encap_str(encap_type);
116
117 if (encap_type_str) {
118 rcu_read_unlock();
119 request_module("rtnl-lwt-%s", encap_type_str);
120 rcu_read_lock();
121 ops = rcu_dereference(lwtun_encaps[encap_type]);
122 }
123 }
124#endif
125 if (likely(ops && ops->build_state))
126 ret = ops->build_state(dev, encap, family, cfg, lws);
127 rcu_read_unlock();
128
129 return ret;
130}
131EXPORT_SYMBOL(lwtunnel_build_state);
132
133int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate)
134{
135 const struct lwtunnel_encap_ops *ops;
136 struct nlattr *nest;
137 int ret = -EINVAL;
138
139 if (!lwtstate)
140 return 0;
141
142 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
143 lwtstate->type > LWTUNNEL_ENCAP_MAX)
144 return 0;
145
146 ret = -EOPNOTSUPP;
147 nest = nla_nest_start(skb, RTA_ENCAP);
148 rcu_read_lock();
149 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
150 if (likely(ops && ops->fill_encap))
151 ret = ops->fill_encap(skb, lwtstate);
152 rcu_read_unlock();
153
154 if (ret)
155 goto nla_put_failure;
156 nla_nest_end(skb, nest);
157 ret = nla_put_u16(skb, RTA_ENCAP_TYPE, lwtstate->type);
158 if (ret)
159 goto nla_put_failure;
160
161 return 0;
162
163nla_put_failure:
164 nla_nest_cancel(skb, nest);
165
166 return (ret == -EOPNOTSUPP ? 0 : ret);
167}
168EXPORT_SYMBOL(lwtunnel_fill_encap);
169
170int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
171{
172 const struct lwtunnel_encap_ops *ops;
173 int ret = 0;
174
175 if (!lwtstate)
176 return 0;
177
178 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
179 lwtstate->type > LWTUNNEL_ENCAP_MAX)
180 return 0;
181
182 rcu_read_lock();
183 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
184 if (likely(ops && ops->get_encap_size))
185 ret = nla_total_size(ops->get_encap_size(lwtstate));
186 rcu_read_unlock();
187
188 return ret;
189}
190EXPORT_SYMBOL(lwtunnel_get_encap_size);
191
192int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
193{
194 const struct lwtunnel_encap_ops *ops;
195 int ret = 0;
196
197 if (!a && !b)
198 return 0;
199
200 if (!a || !b)
201 return 1;
202
203 if (a->type != b->type)
204 return 1;
205
206 if (a->type == LWTUNNEL_ENCAP_NONE ||
207 a->type > LWTUNNEL_ENCAP_MAX)
208 return 0;
209
210 rcu_read_lock();
211 ops = rcu_dereference(lwtun_encaps[a->type]);
212 if (likely(ops && ops->cmp_encap))
213 ret = ops->cmp_encap(a, b);
214 rcu_read_unlock();
215
216 return ret;
217}
218EXPORT_SYMBOL(lwtunnel_cmp_encap);
219
220int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
221{
222 struct dst_entry *dst = skb_dst(skb);
223 const struct lwtunnel_encap_ops *ops;
224 struct lwtunnel_state *lwtstate;
225 int ret = -EINVAL;
226
227 if (!dst)
228 goto drop;
229 lwtstate = dst->lwtstate;
230
231 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
232 lwtstate->type > LWTUNNEL_ENCAP_MAX)
233 return 0;
234
235 ret = -EOPNOTSUPP;
236 rcu_read_lock();
237 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
238 if (likely(ops && ops->output))
239 ret = ops->output(net, sk, skb);
240 rcu_read_unlock();
241
242 if (ret == -EOPNOTSUPP)
243 goto drop;
244
245 return ret;
246
247drop:
248 kfree_skb(skb);
249
250 return ret;
251}
252EXPORT_SYMBOL(lwtunnel_output);
253
254int lwtunnel_input(struct sk_buff *skb)
255{
256 struct dst_entry *dst = skb_dst(skb);
257 const struct lwtunnel_encap_ops *ops;
258 struct lwtunnel_state *lwtstate;
259 int ret = -EINVAL;
260
261 if (!dst)
262 goto drop;
263 lwtstate = dst->lwtstate;
264
265 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
266 lwtstate->type > LWTUNNEL_ENCAP_MAX)
267 return 0;
268
269 ret = -EOPNOTSUPP;
270 rcu_read_lock();
271 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
272 if (likely(ops && ops->input))
273 ret = ops->input(skb);
274 rcu_read_unlock();
275
276 if (ret == -EOPNOTSUPP)
277 goto drop;
278
279 return ret;
280
281drop:
282 kfree_skb(skb);
283
284 return ret;
285}
286EXPORT_SYMBOL(lwtunnel_input);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * lwtunnel Infrastructure for light weight tunnels like mpls
4 *
5 * Authors: Roopa Prabhu, <roopa@cumulusnetworks.com>
6 */
7
8#include <linux/capability.h>
9#include <linux/module.h>
10#include <linux/types.h>
11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/uaccess.h>
14#include <linux/skbuff.h>
15#include <linux/netdevice.h>
16#include <linux/lwtunnel.h>
17#include <linux/in.h>
18#include <linux/init.h>
19#include <linux/err.h>
20
21#include <net/lwtunnel.h>
22#include <net/rtnetlink.h>
23#include <net/ip6_fib.h>
24#include <net/rtnh.h>
25
26DEFINE_STATIC_KEY_FALSE(nf_hooks_lwtunnel_enabled);
27EXPORT_SYMBOL_GPL(nf_hooks_lwtunnel_enabled);
28
29#ifdef CONFIG_MODULES
30
31static const char *lwtunnel_encap_str(enum lwtunnel_encap_types encap_type)
32{
33 /* Only lwt encaps implemented without using an interface for
34 * the encap need to return a string here.
35 */
36 switch (encap_type) {
37 case LWTUNNEL_ENCAP_MPLS:
38 return "MPLS";
39 case LWTUNNEL_ENCAP_ILA:
40 return "ILA";
41 case LWTUNNEL_ENCAP_SEG6:
42 return "SEG6";
43 case LWTUNNEL_ENCAP_BPF:
44 return "BPF";
45 case LWTUNNEL_ENCAP_SEG6_LOCAL:
46 return "SEG6LOCAL";
47 case LWTUNNEL_ENCAP_RPL:
48 return "RPL";
49 case LWTUNNEL_ENCAP_IOAM6:
50 return "IOAM6";
51 case LWTUNNEL_ENCAP_XFRM:
52 /* module autoload not supported for encap type */
53 return NULL;
54 case LWTUNNEL_ENCAP_IP6:
55 case LWTUNNEL_ENCAP_IP:
56 case LWTUNNEL_ENCAP_NONE:
57 case __LWTUNNEL_ENCAP_MAX:
58 /* should not have got here */
59 WARN_ON(1);
60 break;
61 }
62 return NULL;
63}
64
65#endif /* CONFIG_MODULES */
66
67struct lwtunnel_state *lwtunnel_state_alloc(int encap_len)
68{
69 struct lwtunnel_state *lws;
70
71 lws = kzalloc(sizeof(*lws) + encap_len, GFP_ATOMIC);
72
73 return lws;
74}
75EXPORT_SYMBOL_GPL(lwtunnel_state_alloc);
76
77static const struct lwtunnel_encap_ops __rcu *
78 lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly;
79
80int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops,
81 unsigned int num)
82{
83 if (num > LWTUNNEL_ENCAP_MAX)
84 return -ERANGE;
85
86 return !cmpxchg((const struct lwtunnel_encap_ops **)
87 &lwtun_encaps[num],
88 NULL, ops) ? 0 : -1;
89}
90EXPORT_SYMBOL_GPL(lwtunnel_encap_add_ops);
91
92int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *ops,
93 unsigned int encap_type)
94{
95 int ret;
96
97 if (encap_type == LWTUNNEL_ENCAP_NONE ||
98 encap_type > LWTUNNEL_ENCAP_MAX)
99 return -ERANGE;
100
101 ret = (cmpxchg((const struct lwtunnel_encap_ops **)
102 &lwtun_encaps[encap_type],
103 ops, NULL) == ops) ? 0 : -1;
104
105 synchronize_net();
106
107 return ret;
108}
109EXPORT_SYMBOL_GPL(lwtunnel_encap_del_ops);
110
111int lwtunnel_build_state(struct net *net, u16 encap_type,
112 struct nlattr *encap, unsigned int family,
113 const void *cfg, struct lwtunnel_state **lws,
114 struct netlink_ext_ack *extack)
115{
116 const struct lwtunnel_encap_ops *ops;
117 bool found = false;
118 int ret = -EINVAL;
119
120 if (encap_type == LWTUNNEL_ENCAP_NONE ||
121 encap_type > LWTUNNEL_ENCAP_MAX) {
122 NL_SET_ERR_MSG_ATTR(extack, encap,
123 "Unknown LWT encapsulation type");
124 return ret;
125 }
126
127 ret = -EOPNOTSUPP;
128 rcu_read_lock();
129 ops = rcu_dereference(lwtun_encaps[encap_type]);
130 if (likely(ops && ops->build_state && try_module_get(ops->owner)))
131 found = true;
132 rcu_read_unlock();
133
134 if (found) {
135 ret = ops->build_state(net, encap, family, cfg, lws, extack);
136 if (ret)
137 module_put(ops->owner);
138 } else {
139 /* don't rely on -EOPNOTSUPP to detect match as build_state
140 * handlers could return it
141 */
142 NL_SET_ERR_MSG_ATTR(extack, encap,
143 "LWT encapsulation type not supported");
144 }
145
146 return ret;
147}
148EXPORT_SYMBOL_GPL(lwtunnel_build_state);
149
150int lwtunnel_valid_encap_type(u16 encap_type, struct netlink_ext_ack *extack)
151{
152 const struct lwtunnel_encap_ops *ops;
153 int ret = -EINVAL;
154
155 if (encap_type == LWTUNNEL_ENCAP_NONE ||
156 encap_type > LWTUNNEL_ENCAP_MAX) {
157 NL_SET_ERR_MSG(extack, "Unknown lwt encapsulation type");
158 return ret;
159 }
160
161 rcu_read_lock();
162 ops = rcu_dereference(lwtun_encaps[encap_type]);
163 rcu_read_unlock();
164#ifdef CONFIG_MODULES
165 if (!ops) {
166 const char *encap_type_str = lwtunnel_encap_str(encap_type);
167
168 if (encap_type_str) {
169 __rtnl_unlock();
170 request_module("rtnl-lwt-%s", encap_type_str);
171 rtnl_lock();
172
173 rcu_read_lock();
174 ops = rcu_dereference(lwtun_encaps[encap_type]);
175 rcu_read_unlock();
176 }
177 }
178#endif
179 ret = ops ? 0 : -EOPNOTSUPP;
180 if (ret < 0)
181 NL_SET_ERR_MSG(extack, "lwt encapsulation type not supported");
182
183 return ret;
184}
185EXPORT_SYMBOL_GPL(lwtunnel_valid_encap_type);
186
187int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int remaining,
188 struct netlink_ext_ack *extack)
189{
190 struct rtnexthop *rtnh = (struct rtnexthop *)attr;
191 struct nlattr *nla_entype;
192 struct nlattr *attrs;
193 u16 encap_type;
194 int attrlen;
195
196 while (rtnh_ok(rtnh, remaining)) {
197 attrlen = rtnh_attrlen(rtnh);
198 if (attrlen > 0) {
199 attrs = rtnh_attrs(rtnh);
200 nla_entype = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
201
202 if (nla_entype) {
203 if (nla_len(nla_entype) < sizeof(u16)) {
204 NL_SET_ERR_MSG(extack, "Invalid RTA_ENCAP_TYPE");
205 return -EINVAL;
206 }
207 encap_type = nla_get_u16(nla_entype);
208
209 if (lwtunnel_valid_encap_type(encap_type,
210 extack) != 0)
211 return -EOPNOTSUPP;
212 }
213 }
214 rtnh = rtnh_next(rtnh, &remaining);
215 }
216
217 return 0;
218}
219EXPORT_SYMBOL_GPL(lwtunnel_valid_encap_type_attr);
220
221void lwtstate_free(struct lwtunnel_state *lws)
222{
223 const struct lwtunnel_encap_ops *ops = lwtun_encaps[lws->type];
224
225 if (ops->destroy_state) {
226 ops->destroy_state(lws);
227 kfree_rcu(lws, rcu);
228 } else {
229 kfree(lws);
230 }
231 module_put(ops->owner);
232}
233EXPORT_SYMBOL_GPL(lwtstate_free);
234
235int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate,
236 int encap_attr, int encap_type_attr)
237{
238 const struct lwtunnel_encap_ops *ops;
239 struct nlattr *nest;
240 int ret;
241
242 if (!lwtstate)
243 return 0;
244
245 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
246 lwtstate->type > LWTUNNEL_ENCAP_MAX)
247 return 0;
248
249 nest = nla_nest_start_noflag(skb, encap_attr);
250 if (!nest)
251 return -EMSGSIZE;
252
253 ret = -EOPNOTSUPP;
254 rcu_read_lock();
255 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
256 if (likely(ops && ops->fill_encap))
257 ret = ops->fill_encap(skb, lwtstate);
258 rcu_read_unlock();
259
260 if (ret)
261 goto nla_put_failure;
262 nla_nest_end(skb, nest);
263 ret = nla_put_u16(skb, encap_type_attr, lwtstate->type);
264 if (ret)
265 goto nla_put_failure;
266
267 return 0;
268
269nla_put_failure:
270 nla_nest_cancel(skb, nest);
271
272 return (ret == -EOPNOTSUPP ? 0 : ret);
273}
274EXPORT_SYMBOL_GPL(lwtunnel_fill_encap);
275
276int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
277{
278 const struct lwtunnel_encap_ops *ops;
279 int ret = 0;
280
281 if (!lwtstate)
282 return 0;
283
284 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
285 lwtstate->type > LWTUNNEL_ENCAP_MAX)
286 return 0;
287
288 rcu_read_lock();
289 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
290 if (likely(ops && ops->get_encap_size))
291 ret = nla_total_size(ops->get_encap_size(lwtstate));
292 rcu_read_unlock();
293
294 return ret;
295}
296EXPORT_SYMBOL_GPL(lwtunnel_get_encap_size);
297
298int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
299{
300 const struct lwtunnel_encap_ops *ops;
301 int ret = 0;
302
303 if (!a && !b)
304 return 0;
305
306 if (!a || !b)
307 return 1;
308
309 if (a->type != b->type)
310 return 1;
311
312 if (a->type == LWTUNNEL_ENCAP_NONE ||
313 a->type > LWTUNNEL_ENCAP_MAX)
314 return 0;
315
316 rcu_read_lock();
317 ops = rcu_dereference(lwtun_encaps[a->type]);
318 if (likely(ops && ops->cmp_encap))
319 ret = ops->cmp_encap(a, b);
320 rcu_read_unlock();
321
322 return ret;
323}
324EXPORT_SYMBOL_GPL(lwtunnel_cmp_encap);
325
326int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
327{
328 struct dst_entry *dst = skb_dst(skb);
329 const struct lwtunnel_encap_ops *ops;
330 struct lwtunnel_state *lwtstate;
331 int ret = -EINVAL;
332
333 if (!dst)
334 goto drop;
335 lwtstate = dst->lwtstate;
336
337 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
338 lwtstate->type > LWTUNNEL_ENCAP_MAX)
339 return 0;
340
341 ret = -EOPNOTSUPP;
342 rcu_read_lock();
343 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
344 if (likely(ops && ops->output))
345 ret = ops->output(net, sk, skb);
346 rcu_read_unlock();
347
348 if (ret == -EOPNOTSUPP)
349 goto drop;
350
351 return ret;
352
353drop:
354 kfree_skb(skb);
355
356 return ret;
357}
358EXPORT_SYMBOL_GPL(lwtunnel_output);
359
360int lwtunnel_xmit(struct sk_buff *skb)
361{
362 struct dst_entry *dst = skb_dst(skb);
363 const struct lwtunnel_encap_ops *ops;
364 struct lwtunnel_state *lwtstate;
365 int ret = -EINVAL;
366
367 if (!dst)
368 goto drop;
369
370 lwtstate = dst->lwtstate;
371
372 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
373 lwtstate->type > LWTUNNEL_ENCAP_MAX)
374 return 0;
375
376 ret = -EOPNOTSUPP;
377 rcu_read_lock();
378 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
379 if (likely(ops && ops->xmit))
380 ret = ops->xmit(skb);
381 rcu_read_unlock();
382
383 if (ret == -EOPNOTSUPP)
384 goto drop;
385
386 return ret;
387
388drop:
389 kfree_skb(skb);
390
391 return ret;
392}
393EXPORT_SYMBOL_GPL(lwtunnel_xmit);
394
395int lwtunnel_input(struct sk_buff *skb)
396{
397 struct dst_entry *dst = skb_dst(skb);
398 const struct lwtunnel_encap_ops *ops;
399 struct lwtunnel_state *lwtstate;
400 int ret = -EINVAL;
401
402 if (!dst)
403 goto drop;
404 lwtstate = dst->lwtstate;
405
406 if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
407 lwtstate->type > LWTUNNEL_ENCAP_MAX)
408 return 0;
409
410 ret = -EOPNOTSUPP;
411 rcu_read_lock();
412 ops = rcu_dereference(lwtun_encaps[lwtstate->type]);
413 if (likely(ops && ops->input))
414 ret = ops->input(skb);
415 rcu_read_unlock();
416
417 if (ret == -EOPNOTSUPP)
418 goto drop;
419
420 return ret;
421
422drop:
423 kfree_skb(skb);
424
425 return ret;
426}
427EXPORT_SYMBOL_GPL(lwtunnel_input);