1 /* L3/L4 protocol support for nf_conntrack. */
2
3 /* (C) 1999-2001 Paul `Rusty' Russell
4 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
5 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/types.h>
14 #include <linux/netfilter.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/mutex.h>
18 #include <linux/vmalloc.h>
19 #include <linux/stddef.h>
20 #include <linux/err.h>
21 #include <linux/percpu.h>
22 #include <linux/notifier.h>
23 #include <linux/kernel.h>
24 #include <linux/netdevice.h>
25
26 #include <net/netfilter/nf_conntrack.h>
27 #include <net/netfilter/nf_conntrack_l3proto.h>
28 #include <net/netfilter/nf_conntrack_l4proto.h>
29 #include <net/netfilter/nf_conntrack_core.h>
30
31 static struct nf_conntrack_l4proto __rcu **nf_ct_protos[PF_MAX] __read_mostly;
32 struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX] __read_mostly;
33 EXPORT_SYMBOL_GPL(nf_ct_l3protos);
34
35 static DEFINE_MUTEX(nf_ct_proto_mutex);
36
37 #ifdef CONFIG_SYSCTL
38 static int
nf_ct_register_sysctl(struct net * net,struct ctl_table_header ** header,const char * path,struct ctl_table * table)39 nf_ct_register_sysctl(struct net *net,
40 struct ctl_table_header **header,
41 const char *path,
42 struct ctl_table *table)
43 {
44 if (*header == NULL) {
45 *header = register_net_sysctl(net, path, table);
46 if (*header == NULL)
47 return -ENOMEM;
48 }
49
50 return 0;
51 }
52
53 static void
nf_ct_unregister_sysctl(struct ctl_table_header ** header,struct ctl_table ** table,unsigned int users)54 nf_ct_unregister_sysctl(struct ctl_table_header **header,
55 struct ctl_table **table,
56 unsigned int users)
57 {
58 if (users > 0)
59 return;
60
61 unregister_net_sysctl_table(*header);
62 kfree(*table);
63 *header = NULL;
64 *table = NULL;
65 }
66 #endif
67
68 struct nf_conntrack_l4proto *
__nf_ct_l4proto_find(u_int16_t l3proto,u_int8_t l4proto)69 __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
70 {
71 if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
72 return &nf_conntrack_l4proto_generic;
73
74 return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
75 }
76 EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
77
78 /* this is guaranteed to always return a valid protocol helper, since
79 * it falls back to generic_protocol */
80 struct nf_conntrack_l3proto *
nf_ct_l3proto_find_get(u_int16_t l3proto)81 nf_ct_l3proto_find_get(u_int16_t l3proto)
82 {
83 struct nf_conntrack_l3proto *p;
84
85 rcu_read_lock();
86 p = __nf_ct_l3proto_find(l3proto);
87 if (!try_module_get(p->me))
88 p = &nf_conntrack_l3proto_generic;
89 rcu_read_unlock();
90
91 return p;
92 }
93 EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
94
nf_ct_l3proto_put(struct nf_conntrack_l3proto * p)95 void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
96 {
97 module_put(p->me);
98 }
99 EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
100
101 int
nf_ct_l3proto_try_module_get(unsigned short l3proto)102 nf_ct_l3proto_try_module_get(unsigned short l3proto)
103 {
104 int ret;
105 struct nf_conntrack_l3proto *p;
106
107 retry: p = nf_ct_l3proto_find_get(l3proto);
108 if (p == &nf_conntrack_l3proto_generic) {
109 ret = request_module("nf_conntrack-%d", l3proto);
110 if (!ret)
111 goto retry;
112
113 return -EPROTOTYPE;
114 }
115
116 return 0;
117 }
118 EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
119
nf_ct_l3proto_module_put(unsigned short l3proto)120 void nf_ct_l3proto_module_put(unsigned short l3proto)
121 {
122 struct nf_conntrack_l3proto *p;
123
124 /* rcu_read_lock not necessary since the caller holds a reference, but
125 * taken anyways to avoid lockdep warnings in __nf_ct_l3proto_find()
126 */
127 rcu_read_lock();
128 p = __nf_ct_l3proto_find(l3proto);
129 module_put(p->me);
130 rcu_read_unlock();
131 }
132 EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
133
134 struct nf_conntrack_l4proto *
nf_ct_l4proto_find_get(u_int16_t l3num,u_int8_t l4num)135 nf_ct_l4proto_find_get(u_int16_t l3num, u_int8_t l4num)
136 {
137 struct nf_conntrack_l4proto *p;
138
139 rcu_read_lock();
140 p = __nf_ct_l4proto_find(l3num, l4num);
141 if (!try_module_get(p->me))
142 p = &nf_conntrack_l4proto_generic;
143 rcu_read_unlock();
144
145 return p;
146 }
147 EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
148
nf_ct_l4proto_put(struct nf_conntrack_l4proto * p)149 void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
150 {
151 module_put(p->me);
152 }
153 EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
154
kill_l3proto(struct nf_conn * i,void * data)155 static int kill_l3proto(struct nf_conn *i, void *data)
156 {
157 return nf_ct_l3num(i) == ((struct nf_conntrack_l3proto *)data)->l3proto;
158 }
159
kill_l4proto(struct nf_conn * i,void * data)160 static int kill_l4proto(struct nf_conn *i, void *data)
161 {
162 struct nf_conntrack_l4proto *l4proto;
163 l4proto = (struct nf_conntrack_l4proto *)data;
164 return nf_ct_protonum(i) == l4proto->l4proto &&
165 nf_ct_l3num(i) == l4proto->l3proto;
166 }
167
nf_ct_l3proto_net(struct net * net,struct nf_conntrack_l3proto * l3proto)168 static struct nf_ip_net *nf_ct_l3proto_net(struct net *net,
169 struct nf_conntrack_l3proto *l3proto)
170 {
171 if (l3proto->l3proto == PF_INET)
172 return &net->ct.nf_ct_proto;
173 else
174 return NULL;
175 }
176
nf_ct_l3proto_register_sysctl(struct net * net,struct nf_conntrack_l3proto * l3proto)177 static int nf_ct_l3proto_register_sysctl(struct net *net,
178 struct nf_conntrack_l3proto *l3proto)
179 {
180 int err = 0;
181 struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto);
182 /* nf_conntrack_l3proto_ipv6 doesn't support sysctl */
183 if (in == NULL)
184 return 0;
185
186 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
187 if (in->ctl_table != NULL) {
188 err = nf_ct_register_sysctl(net,
189 &in->ctl_table_header,
190 l3proto->ctl_table_path,
191 in->ctl_table);
192 if (err < 0) {
193 kfree(in->ctl_table);
194 in->ctl_table = NULL;
195 }
196 }
197 #endif
198 return err;
199 }
200
nf_ct_l3proto_unregister_sysctl(struct net * net,struct nf_conntrack_l3proto * l3proto)201 static void nf_ct_l3proto_unregister_sysctl(struct net *net,
202 struct nf_conntrack_l3proto *l3proto)
203 {
204 struct nf_ip_net *in = nf_ct_l3proto_net(net, l3proto);
205
206 if (in == NULL)
207 return;
208 #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
209 if (in->ctl_table_header != NULL)
210 nf_ct_unregister_sysctl(&in->ctl_table_header,
211 &in->ctl_table,
212 0);
213 #endif
214 }
215
nf_ct_l3proto_register(struct nf_conntrack_l3proto * proto)216 int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto)
217 {
218 int ret = 0;
219 struct nf_conntrack_l3proto *old;
220
221 if (proto->l3proto >= AF_MAX)
222 return -EBUSY;
223
224 if (proto->tuple_to_nlattr && !proto->nlattr_tuple_size)
225 return -EINVAL;
226
227 mutex_lock(&nf_ct_proto_mutex);
228 old = rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
229 lockdep_is_held(&nf_ct_proto_mutex));
230 if (old != &nf_conntrack_l3proto_generic) {
231 ret = -EBUSY;
232 goto out_unlock;
233 }
234
235 if (proto->nlattr_tuple_size)
236 proto->nla_size = 3 * proto->nlattr_tuple_size();
237
238 rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
239
240 out_unlock:
241 mutex_unlock(&nf_ct_proto_mutex);
242 return ret;
243
244 }
245 EXPORT_SYMBOL_GPL(nf_ct_l3proto_register);
246
nf_ct_l3proto_pernet_register(struct net * net,struct nf_conntrack_l3proto * proto)247 int nf_ct_l3proto_pernet_register(struct net *net,
248 struct nf_conntrack_l3proto *proto)
249 {
250 int ret = 0;
251
252 if (proto->init_net) {
253 ret = proto->init_net(net);
254 if (ret < 0)
255 return ret;
256 }
257
258 return nf_ct_l3proto_register_sysctl(net, proto);
259 }
260 EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_register);
261
nf_ct_l3proto_unregister(struct nf_conntrack_l3proto * proto)262 void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto)
263 {
264 BUG_ON(proto->l3proto >= AF_MAX);
265
266 mutex_lock(&nf_ct_proto_mutex);
267 BUG_ON(rcu_dereference_protected(nf_ct_l3protos[proto->l3proto],
268 lockdep_is_held(&nf_ct_proto_mutex)
269 ) != proto);
270 rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
271 &nf_conntrack_l3proto_generic);
272 mutex_unlock(&nf_ct_proto_mutex);
273
274 synchronize_rcu();
275 }
276 EXPORT_SYMBOL_GPL(nf_ct_l3proto_unregister);
277
nf_ct_l3proto_pernet_unregister(struct net * net,struct nf_conntrack_l3proto * proto)278 void nf_ct_l3proto_pernet_unregister(struct net *net,
279 struct nf_conntrack_l3proto *proto)
280 {
281 nf_ct_l3proto_unregister_sysctl(net, proto);
282
283 /* Remove all contrack entries for this protocol */
284 nf_ct_iterate_cleanup(net, kill_l3proto, proto);
285 }
286 EXPORT_SYMBOL_GPL(nf_ct_l3proto_pernet_unregister);
287
nf_ct_l4proto_net(struct net * net,struct nf_conntrack_l4proto * l4proto)288 static struct nf_proto_net *nf_ct_l4proto_net(struct net *net,
289 struct nf_conntrack_l4proto *l4proto)
290 {
291 if (l4proto->get_net_proto) {
292 /* statically built-in protocols use static per-net */
293 return l4proto->get_net_proto(net);
294 } else if (l4proto->net_id) {
295 /* ... and loadable protocols use dynamic per-net */
296 return net_generic(net, *l4proto->net_id);
297 }
298 return NULL;
299 }
300
301 static
nf_ct_l4proto_register_sysctl(struct net * net,struct nf_proto_net * pn,struct nf_conntrack_l4proto * l4proto)302 int nf_ct_l4proto_register_sysctl(struct net *net,
303 struct nf_proto_net *pn,
304 struct nf_conntrack_l4proto *l4proto)
305 {
306 int err = 0;
307
308 #ifdef CONFIG_SYSCTL
309 if (pn->ctl_table != NULL) {
310 err = nf_ct_register_sysctl(net,
311 &pn->ctl_table_header,
312 "net/netfilter",
313 pn->ctl_table);
314 if (err < 0) {
315 if (!pn->users) {
316 kfree(pn->ctl_table);
317 pn->ctl_table = NULL;
318 }
319 }
320 }
321 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
322 if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_table != NULL) {
323 if (err < 0) {
324 nf_ct_kfree_compat_sysctl_table(pn);
325 goto out;
326 }
327 err = nf_ct_register_sysctl(net,
328 &pn->ctl_compat_header,
329 "net/ipv4/netfilter",
330 pn->ctl_compat_table);
331 if (err == 0)
332 goto out;
333
334 nf_ct_kfree_compat_sysctl_table(pn);
335 nf_ct_unregister_sysctl(&pn->ctl_table_header,
336 &pn->ctl_table,
337 pn->users);
338 }
339 out:
340 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
341 #endif /* CONFIG_SYSCTL */
342 return err;
343 }
344
345 static
nf_ct_l4proto_unregister_sysctl(struct net * net,struct nf_proto_net * pn,struct nf_conntrack_l4proto * l4proto)346 void nf_ct_l4proto_unregister_sysctl(struct net *net,
347 struct nf_proto_net *pn,
348 struct nf_conntrack_l4proto *l4proto)
349 {
350 #ifdef CONFIG_SYSCTL
351 if (pn->ctl_table_header != NULL)
352 nf_ct_unregister_sysctl(&pn->ctl_table_header,
353 &pn->ctl_table,
354 pn->users);
355
356 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
357 if (l4proto->l3proto != AF_INET6 && pn->ctl_compat_header != NULL)
358 nf_ct_unregister_sysctl(&pn->ctl_compat_header,
359 &pn->ctl_compat_table,
360 0);
361 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
362 #endif /* CONFIG_SYSCTL */
363 }
364
365 /* FIXME: Allow NULL functions and sub in pointers to generic for
366 them. --RR */
nf_ct_l4proto_register(struct nf_conntrack_l4proto * l4proto)367 int nf_ct_l4proto_register(struct nf_conntrack_l4proto *l4proto)
368 {
369 int ret = 0;
370
371 if (l4proto->l3proto >= PF_MAX)
372 return -EBUSY;
373
374 if ((l4proto->to_nlattr && !l4proto->nlattr_size)
375 || (l4proto->tuple_to_nlattr && !l4proto->nlattr_tuple_size))
376 return -EINVAL;
377
378 mutex_lock(&nf_ct_proto_mutex);
379 if (!nf_ct_protos[l4proto->l3proto]) {
380 /* l3proto may be loaded latter. */
381 struct nf_conntrack_l4proto __rcu **proto_array;
382 int i;
383
384 proto_array = kmalloc(MAX_NF_CT_PROTO *
385 sizeof(struct nf_conntrack_l4proto *),
386 GFP_KERNEL);
387 if (proto_array == NULL) {
388 ret = -ENOMEM;
389 goto out_unlock;
390 }
391
392 for (i = 0; i < MAX_NF_CT_PROTO; i++)
393 RCU_INIT_POINTER(proto_array[i], &nf_conntrack_l4proto_generic);
394
395 /* Before making proto_array visible to lockless readers,
396 * we must make sure its content is committed to memory.
397 */
398 smp_wmb();
399
400 nf_ct_protos[l4proto->l3proto] = proto_array;
401 } else if (rcu_dereference_protected(
402 nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
403 lockdep_is_held(&nf_ct_proto_mutex)
404 ) != &nf_conntrack_l4proto_generic) {
405 ret = -EBUSY;
406 goto out_unlock;
407 }
408
409 l4proto->nla_size = 0;
410 if (l4proto->nlattr_size)
411 l4proto->nla_size += l4proto->nlattr_size();
412 if (l4proto->nlattr_tuple_size)
413 l4proto->nla_size += 3 * l4proto->nlattr_tuple_size();
414
415 rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
416 l4proto);
417 out_unlock:
418 mutex_unlock(&nf_ct_proto_mutex);
419 return ret;
420 }
421 EXPORT_SYMBOL_GPL(nf_ct_l4proto_register);
422
nf_ct_l4proto_pernet_register(struct net * net,struct nf_conntrack_l4proto * l4proto)423 int nf_ct_l4proto_pernet_register(struct net *net,
424 struct nf_conntrack_l4proto *l4proto)
425 {
426 int ret = 0;
427 struct nf_proto_net *pn = NULL;
428
429 if (l4proto->init_net) {
430 ret = l4proto->init_net(net, l4proto->l3proto);
431 if (ret < 0)
432 goto out;
433 }
434
435 pn = nf_ct_l4proto_net(net, l4proto);
436 if (pn == NULL)
437 goto out;
438
439 ret = nf_ct_l4proto_register_sysctl(net, pn, l4proto);
440 if (ret < 0)
441 goto out;
442
443 pn->users++;
444 out:
445 return ret;
446 }
447 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_register);
448
nf_ct_l4proto_unregister(struct nf_conntrack_l4proto * l4proto)449 void nf_ct_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
450 {
451 BUG_ON(l4proto->l3proto >= PF_MAX);
452
453 mutex_lock(&nf_ct_proto_mutex);
454 BUG_ON(rcu_dereference_protected(
455 nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
456 lockdep_is_held(&nf_ct_proto_mutex)
457 ) != l4proto);
458 rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
459 &nf_conntrack_l4proto_generic);
460 mutex_unlock(&nf_ct_proto_mutex);
461
462 synchronize_rcu();
463 }
464 EXPORT_SYMBOL_GPL(nf_ct_l4proto_unregister);
465
nf_ct_l4proto_pernet_unregister(struct net * net,struct nf_conntrack_l4proto * l4proto)466 void nf_ct_l4proto_pernet_unregister(struct net *net,
467 struct nf_conntrack_l4proto *l4proto)
468 {
469 struct nf_proto_net *pn = NULL;
470
471 pn = nf_ct_l4proto_net(net, l4proto);
472 if (pn == NULL)
473 return;
474
475 pn->users--;
476 nf_ct_l4proto_unregister_sysctl(net, pn, l4proto);
477
478 /* Remove all contrack entries for this protocol */
479 nf_ct_iterate_cleanup(net, kill_l4proto, l4proto);
480 }
481 EXPORT_SYMBOL_GPL(nf_ct_l4proto_pernet_unregister);
482
nf_conntrack_proto_pernet_init(struct net * net)483 int nf_conntrack_proto_pernet_init(struct net *net)
484 {
485 int err;
486 struct nf_proto_net *pn = nf_ct_l4proto_net(net,
487 &nf_conntrack_l4proto_generic);
488
489 err = nf_conntrack_l4proto_generic.init_net(net,
490 nf_conntrack_l4proto_generic.l3proto);
491 if (err < 0)
492 return err;
493 err = nf_ct_l4proto_register_sysctl(net,
494 pn,
495 &nf_conntrack_l4proto_generic);
496 if (err < 0)
497 return err;
498
499 pn->users++;
500 return 0;
501 }
502
nf_conntrack_proto_pernet_fini(struct net * net)503 void nf_conntrack_proto_pernet_fini(struct net *net)
504 {
505 struct nf_proto_net *pn = nf_ct_l4proto_net(net,
506 &nf_conntrack_l4proto_generic);
507
508 pn->users--;
509 nf_ct_l4proto_unregister_sysctl(net,
510 pn,
511 &nf_conntrack_l4proto_generic);
512 }
513
nf_conntrack_proto_init(void)514 int nf_conntrack_proto_init(void)
515 {
516 unsigned int i;
517 for (i = 0; i < AF_MAX; i++)
518 rcu_assign_pointer(nf_ct_l3protos[i],
519 &nf_conntrack_l3proto_generic);
520 return 0;
521 }
522
nf_conntrack_proto_fini(void)523 void nf_conntrack_proto_fini(void)
524 {
525 unsigned int i;
526 /* free l3proto protocol tables */
527 for (i = 0; i < PF_MAX; i++)
528 kfree(nf_ct_protos[i]);
529 }
530