tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
3 * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation (or any later at your option).
8 */
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/rculist.h>
13#include <linux/rculist_nulls.h>
14#include <linux/types.h>
15#include <linux/timer.h>
16#include <linux/security.h>
17#include <linux/skbuff.h>
18#include <linux/errno.h>
19#include <linux/netlink.h>
20#include <linux/spinlock.h>
21#include <linux/interrupt.h>
22#include <linux/slab.h>
23
24#include <linux/netfilter.h>
25#include <net/netlink.h>
26#include <net/sock.h>
27#include <net/netfilter/nf_conntrack.h>
28#include <net/netfilter/nf_conntrack_core.h>
29#include <net/netfilter/nf_conntrack_l3proto.h>
30#include <net/netfilter/nf_conntrack_l4proto.h>
31#include <net/netfilter/nf_conntrack_tuple.h>
32#include <net/netfilter/nf_conntrack_timeout.h>
33
34#include <linux/netfilter/nfnetlink.h>
35#include <linux/netfilter/nfnetlink_cttimeout.h>
36
37MODULE_LICENSE("GPL");
38MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
39MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
40
41static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
42 [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING,
43 .len = CTNL_TIMEOUT_NAME_MAX - 1},
44 [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 },
45 [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 },
46 [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED },
47};
48
49static int
50ctnl_timeout_parse_policy(void *timeouts,
51 const struct nf_conntrack_l4proto *l4proto,
52 struct net *net, const struct nlattr *attr)
53{
54 struct nlattr **tb;
55 int ret = 0;
56
57 if (!l4proto->ctnl_timeout.nlattr_to_obj)
58 return 0;
59
60 tb = kcalloc(l4proto->ctnl_timeout.nlattr_max + 1, sizeof(*tb),
61 GFP_KERNEL);
62
63 if (!tb)
64 return -ENOMEM;
65
66 ret = nla_parse_nested(tb, l4proto->ctnl_timeout.nlattr_max, attr,
67 l4proto->ctnl_timeout.nla_policy, NULL);
68 if (ret < 0)
69 goto err;
70
71 ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeouts);
72
73err:
74 kfree(tb);
75 return ret;
76}
77
78static int cttimeout_new_timeout(struct net *net, struct sock *ctnl,
79 struct sk_buff *skb,
80 const struct nlmsghdr *nlh,
81 const struct nlattr * const cda[],
82 struct netlink_ext_ack *extack)
83{
84 __u16 l3num;
85 __u8 l4num;
86 const struct nf_conntrack_l4proto *l4proto;
87 struct ctnl_timeout *timeout, *matching = NULL;
88 char *name;
89 int ret;
90
91 if (!cda[CTA_TIMEOUT_NAME] ||
92 !cda[CTA_TIMEOUT_L3PROTO] ||
93 !cda[CTA_TIMEOUT_L4PROTO] ||
94 !cda[CTA_TIMEOUT_DATA])
95 return -EINVAL;
96
97 name = nla_data(cda[CTA_TIMEOUT_NAME]);
98 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
99 l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
100
101 list_for_each_entry(timeout, &net->nfct_timeout_list, head) {
102 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
103 continue;
104
105 if (nlh->nlmsg_flags & NLM_F_EXCL)
106 return -EEXIST;
107
108 matching = timeout;
109 break;
110 }
111
112 if (matching) {
113 if (nlh->nlmsg_flags & NLM_F_REPLACE) {
114 /* You cannot replace one timeout policy by another of
115 * different kind, sorry.
116 */
117 if (matching->l3num != l3num ||
118 matching->l4proto->l4proto != l4num)
119 return -EINVAL;
120
121 return ctnl_timeout_parse_policy(&matching->data,
122 matching->l4proto, net,
123 cda[CTA_TIMEOUT_DATA]);
124 }
125
126 return -EBUSY;
127 }
128
129 l4proto = nf_ct_l4proto_find_get(l3num, l4num);
130
131 /* This protocol is not supportted, skip. */
132 if (l4proto->l4proto != l4num) {
133 ret = -EOPNOTSUPP;
134 goto err_proto_put;
135 }
136
137 timeout = kzalloc(sizeof(struct ctnl_timeout) +
138 l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
139 if (timeout == NULL) {
140 ret = -ENOMEM;
141 goto err_proto_put;
142 }
143
144 ret = ctnl_timeout_parse_policy(&timeout->data, l4proto, net,
145 cda[CTA_TIMEOUT_DATA]);
146 if (ret < 0)
147 goto err;
148
149 strcpy(timeout->name, nla_data(cda[CTA_TIMEOUT_NAME]));
150 timeout->l3num = l3num;
151 timeout->l4proto = l4proto;
152 refcount_set(&timeout->refcnt, 1);
153 list_add_tail_rcu(&timeout->head, &net->nfct_timeout_list);
154
155 return 0;
156err:
157 kfree(timeout);
158err_proto_put:
159 nf_ct_l4proto_put(l4proto);
160 return ret;
161}
162
163static int
164ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
165 int event, struct ctnl_timeout *timeout)
166{
167 struct nlmsghdr *nlh;
168 struct nfgenmsg *nfmsg;
169 unsigned int flags = portid ? NLM_F_MULTI : 0;
170 const struct nf_conntrack_l4proto *l4proto = timeout->l4proto;
171
172 event = nfnl_msg_type(NFNL_SUBSYS_CTNETLINK_TIMEOUT, event);
173 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
174 if (nlh == NULL)
175 goto nlmsg_failure;
176
177 nfmsg = nlmsg_data(nlh);
178 nfmsg->nfgen_family = AF_UNSPEC;
179 nfmsg->version = NFNETLINK_V0;
180 nfmsg->res_id = 0;
181
182 if (nla_put_string(skb, CTA_TIMEOUT_NAME, timeout->name) ||
183 nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(timeout->l3num)) ||
184 nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, timeout->l4proto->l4proto) ||
185 nla_put_be32(skb, CTA_TIMEOUT_USE,
186 htonl(refcount_read(&timeout->refcnt))))
187 goto nla_put_failure;
188
189 if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
190 struct nlattr *nest_parms;
191 int ret;
192
193 nest_parms = nla_nest_start(skb,
194 CTA_TIMEOUT_DATA | NLA_F_NESTED);
195 if (!nest_parms)
196 goto nla_put_failure;
197
198 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->data);
199 if (ret < 0)
200 goto nla_put_failure;
201
202 nla_nest_end(skb, nest_parms);
203 }
204
205 nlmsg_end(skb, nlh);
206 return skb->len;
207
208nlmsg_failure:
209nla_put_failure:
210 nlmsg_cancel(skb, nlh);
211 return -1;
212}
213
214static int
215ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
216{
217 struct net *net = sock_net(skb->sk);
218 struct ctnl_timeout *cur, *last;
219
220 if (cb->args[2])
221 return 0;
222
223 last = (struct ctnl_timeout *)cb->args[1];
224 if (cb->args[1])
225 cb->args[1] = 0;
226
227 rcu_read_lock();
228 list_for_each_entry_rcu(cur, &net->nfct_timeout_list, head) {
229 if (last) {
230 if (cur != last)
231 continue;
232
233 last = NULL;
234 }
235 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid,
236 cb->nlh->nlmsg_seq,
237 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
238 IPCTNL_MSG_TIMEOUT_NEW, cur) < 0) {
239 cb->args[1] = (unsigned long)cur;
240 break;
241 }
242 }
243 if (!cb->args[1])
244 cb->args[2] = 1;
245 rcu_read_unlock();
246 return skb->len;
247}
248
249static int cttimeout_get_timeout(struct net *net, struct sock *ctnl,
250 struct sk_buff *skb,
251 const struct nlmsghdr *nlh,
252 const struct nlattr * const cda[],
253 struct netlink_ext_ack *extack)
254{
255 int ret = -ENOENT;
256 char *name;
257 struct ctnl_timeout *cur;
258
259 if (nlh->nlmsg_flags & NLM_F_DUMP) {
260 struct netlink_dump_control c = {
261 .dump = ctnl_timeout_dump,
262 };
263 return netlink_dump_start(ctnl, skb, nlh, &c);
264 }
265
266 if (!cda[CTA_TIMEOUT_NAME])
267 return -EINVAL;
268 name = nla_data(cda[CTA_TIMEOUT_NAME]);
269
270 list_for_each_entry(cur, &net->nfct_timeout_list, head) {
271 struct sk_buff *skb2;
272
273 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
274 continue;
275
276 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
277 if (skb2 == NULL) {
278 ret = -ENOMEM;
279 break;
280 }
281
282 ret = ctnl_timeout_fill_info(skb2, NETLINK_CB(skb).portid,
283 nlh->nlmsg_seq,
284 NFNL_MSG_TYPE(nlh->nlmsg_type),
285 IPCTNL_MSG_TIMEOUT_NEW, cur);
286 if (ret <= 0) {
287 kfree_skb(skb2);
288 break;
289 }
290 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid,
291 MSG_DONTWAIT);
292 if (ret > 0)
293 ret = 0;
294
295 /* this avoids a loop in nfnetlink. */
296 return ret == -EAGAIN ? -ENOBUFS : ret;
297 }
298 return ret;
299}
300
301static int untimeout(struct nf_conn *ct, void *timeout)
302{
303 struct nf_conn_timeout *timeout_ext = nf_ct_timeout_find(ct);
304
305 if (timeout_ext && (!timeout || timeout_ext->timeout == timeout))
306 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
307
308 /* We are not intended to delete this conntrack. */
309 return 0;
310}
311
312static void ctnl_untimeout(struct net *net, struct ctnl_timeout *timeout)
313{
314 nf_ct_iterate_cleanup_net(net, untimeout, timeout, 0, 0);
315}
316
317/* try to delete object, fail if it is still in use. */
318static int ctnl_timeout_try_del(struct net *net, struct ctnl_timeout *timeout)
319{
320 int ret = 0;
321
322 /* We want to avoid races with ctnl_timeout_put. So only when the
323 * current refcnt is 1, we decrease it to 0.
324 */
325 if (refcount_dec_if_one(&timeout->refcnt)) {
326 /* We are protected by nfnl mutex. */
327 list_del_rcu(&timeout->head);
328 nf_ct_l4proto_put(timeout->l4proto);
329 ctnl_untimeout(net, timeout);
330 kfree_rcu(timeout, rcu_head);
331 } else {
332 ret = -EBUSY;
333 }
334 return ret;
335}
336
337static int cttimeout_del_timeout(struct net *net, struct sock *ctnl,
338 struct sk_buff *skb,
339 const struct nlmsghdr *nlh,
340 const struct nlattr * const cda[],
341 struct netlink_ext_ack *extack)
342{
343 struct ctnl_timeout *cur, *tmp;
344 int ret = -ENOENT;
345 char *name;
346
347 if (!cda[CTA_TIMEOUT_NAME]) {
348 list_for_each_entry_safe(cur, tmp, &net->nfct_timeout_list,
349 head)
350 ctnl_timeout_try_del(net, cur);
351
352 return 0;
353 }
354 name = nla_data(cda[CTA_TIMEOUT_NAME]);
355
356 list_for_each_entry(cur, &net->nfct_timeout_list, head) {
357 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
358 continue;
359
360 ret = ctnl_timeout_try_del(net, cur);
361 if (ret < 0)
362 return ret;
363
364 break;
365 }
366 return ret;
367}
368
369static int cttimeout_default_set(struct net *net, struct sock *ctnl,
370 struct sk_buff *skb,
371 const struct nlmsghdr *nlh,
372 const struct nlattr * const cda[],
373 struct netlink_ext_ack *extack)
374{
375 const struct nf_conntrack_l4proto *l4proto;
376 unsigned int *timeouts;
377 __u16 l3num;
378 __u8 l4num;
379 int ret;
380
381 if (!cda[CTA_TIMEOUT_L3PROTO] ||
382 !cda[CTA_TIMEOUT_L4PROTO] ||
383 !cda[CTA_TIMEOUT_DATA])
384 return -EINVAL;
385
386 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
387 l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
388 l4proto = nf_ct_l4proto_find_get(l3num, l4num);
389
390 /* This protocol is not supported, skip. */
391 if (l4proto->l4proto != l4num) {
392 ret = -EOPNOTSUPP;
393 goto err;
394 }
395
396 timeouts = l4proto->get_timeouts(net);
397
398 ret = ctnl_timeout_parse_policy(timeouts, l4proto, net,
399 cda[CTA_TIMEOUT_DATA]);
400 if (ret < 0)
401 goto err;
402
403 nf_ct_l4proto_put(l4proto);
404 return 0;
405err:
406 nf_ct_l4proto_put(l4proto);
407 return ret;
408}
409
410static int
411cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid,
412 u32 seq, u32 type, int event,
413 const struct nf_conntrack_l4proto *l4proto)
414{
415 struct nlmsghdr *nlh;
416 struct nfgenmsg *nfmsg;
417 unsigned int flags = portid ? NLM_F_MULTI : 0;
418
419 event = nfnl_msg_type(NFNL_SUBSYS_CTNETLINK_TIMEOUT, event);
420 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
421 if (nlh == NULL)
422 goto nlmsg_failure;
423
424 nfmsg = nlmsg_data(nlh);
425 nfmsg->nfgen_family = AF_UNSPEC;
426 nfmsg->version = NFNETLINK_V0;
427 nfmsg->res_id = 0;
428
429 if (nla_put_be16(skb, CTA_TIMEOUT_L3PROTO, htons(l4proto->l3proto)) ||
430 nla_put_u8(skb, CTA_TIMEOUT_L4PROTO, l4proto->l4proto))
431 goto nla_put_failure;
432
433 if (likely(l4proto->ctnl_timeout.obj_to_nlattr)) {
434 struct nlattr *nest_parms;
435 unsigned int *timeouts = l4proto->get_timeouts(net);
436 int ret;
437
438 nest_parms = nla_nest_start(skb,
439 CTA_TIMEOUT_DATA | NLA_F_NESTED);
440 if (!nest_parms)
441 goto nla_put_failure;
442
443 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, timeouts);
444 if (ret < 0)
445 goto nla_put_failure;
446
447 nla_nest_end(skb, nest_parms);
448 }
449
450 nlmsg_end(skb, nlh);
451 return skb->len;
452
453nlmsg_failure:
454nla_put_failure:
455 nlmsg_cancel(skb, nlh);
456 return -1;
457}
458
459static int cttimeout_default_get(struct net *net, struct sock *ctnl,
460 struct sk_buff *skb,
461 const struct nlmsghdr *nlh,
462 const struct nlattr * const cda[],
463 struct netlink_ext_ack *extack)
464{
465 const struct nf_conntrack_l4proto *l4proto;
466 struct sk_buff *skb2;
467 int ret, err;
468 __u16 l3num;
469 __u8 l4num;
470
471 if (!cda[CTA_TIMEOUT_L3PROTO] || !cda[CTA_TIMEOUT_L4PROTO])
472 return -EINVAL;
473
474 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
475 l4num = nla_get_u8(cda[CTA_TIMEOUT_L4PROTO]);
476 l4proto = nf_ct_l4proto_find_get(l3num, l4num);
477
478 /* This protocol is not supported, skip. */
479 if (l4proto->l4proto != l4num) {
480 err = -EOPNOTSUPP;
481 goto err;
482 }
483
484 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
485 if (skb2 == NULL) {
486 err = -ENOMEM;
487 goto err;
488 }
489
490 ret = cttimeout_default_fill_info(net, skb2, NETLINK_CB(skb).portid,
491 nlh->nlmsg_seq,
492 NFNL_MSG_TYPE(nlh->nlmsg_type),
493 IPCTNL_MSG_TIMEOUT_DEFAULT_SET,
494 l4proto);
495 if (ret <= 0) {
496 kfree_skb(skb2);
497 err = -ENOMEM;
498 goto err;
499 }
500 ret = netlink_unicast(ctnl, skb2, NETLINK_CB(skb).portid, MSG_DONTWAIT);
501 if (ret > 0)
502 ret = 0;
503
504 /* this avoids a loop in nfnetlink. */
505 return ret == -EAGAIN ? -ENOBUFS : ret;
506err:
507 nf_ct_l4proto_put(l4proto);
508 return err;
509}
510
511#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
512static struct ctnl_timeout *
513ctnl_timeout_find_get(struct net *net, const char *name)
514{
515 struct ctnl_timeout *timeout, *matching = NULL;
516
517 list_for_each_entry_rcu(timeout, &net->nfct_timeout_list, head) {
518 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
519 continue;
520
521 if (!try_module_get(THIS_MODULE))
522 goto err;
523
524 if (!refcount_inc_not_zero(&timeout->refcnt)) {
525 module_put(THIS_MODULE);
526 goto err;
527 }
528 matching = timeout;
529 break;
530 }
531err:
532 return matching;
533}
534
535static void ctnl_timeout_put(struct ctnl_timeout *timeout)
536{
537 if (refcount_dec_and_test(&timeout->refcnt))
538 kfree_rcu(timeout, rcu_head);
539
540 module_put(THIS_MODULE);
541}
542#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
543
544static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
545 [IPCTNL_MSG_TIMEOUT_NEW] = { .call = cttimeout_new_timeout,
546 .attr_count = CTA_TIMEOUT_MAX,
547 .policy = cttimeout_nla_policy },
548 [IPCTNL_MSG_TIMEOUT_GET] = { .call = cttimeout_get_timeout,
549 .attr_count = CTA_TIMEOUT_MAX,
550 .policy = cttimeout_nla_policy },
551 [IPCTNL_MSG_TIMEOUT_DELETE] = { .call = cttimeout_del_timeout,
552 .attr_count = CTA_TIMEOUT_MAX,
553 .policy = cttimeout_nla_policy },
554 [IPCTNL_MSG_TIMEOUT_DEFAULT_SET]= { .call = cttimeout_default_set,
555 .attr_count = CTA_TIMEOUT_MAX,
556 .policy = cttimeout_nla_policy },
557 [IPCTNL_MSG_TIMEOUT_DEFAULT_GET]= { .call = cttimeout_default_get,
558 .attr_count = CTA_TIMEOUT_MAX,
559 .policy = cttimeout_nla_policy },
560};
561
562static const struct nfnetlink_subsystem cttimeout_subsys = {
563 .name = "conntrack_timeout",
564 .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
565 .cb_count = IPCTNL_MSG_TIMEOUT_MAX,
566 .cb = cttimeout_cb,
567};
568
569MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
570
571static int __net_init cttimeout_net_init(struct net *net)
572{
573 INIT_LIST_HEAD(&net->nfct_timeout_list);
574
575 return 0;
576}
577
578static void __net_exit cttimeout_net_exit(struct net *net)
579{
580 struct ctnl_timeout *cur, *tmp;
581
582 nf_ct_unconfirmed_destroy(net);
583 ctnl_untimeout(net, NULL);
584
585 list_for_each_entry_safe(cur, tmp, &net->nfct_timeout_list, head) {
586 list_del_rcu(&cur->head);
587 nf_ct_l4proto_put(cur->l4proto);
588
589 if (refcount_dec_and_test(&cur->refcnt))
590 kfree_rcu(cur, rcu_head);
591 }
592}
593
594static struct pernet_operations cttimeout_ops = {
595 .init = cttimeout_net_init,
596 .exit = cttimeout_net_exit,
597};
598
599static int __init cttimeout_init(void)
600{
601 int ret;
602
603 ret = register_pernet_subsys(&cttimeout_ops);
604 if (ret < 0)
605 return ret;
606
607 ret = nfnetlink_subsys_register(&cttimeout_subsys);
608 if (ret < 0) {
609 pr_err("cttimeout_init: cannot register cttimeout with "
610 "nfnetlink.\n");
611 goto err_out;
612 }
613#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
614 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, ctnl_timeout_find_get);
615 RCU_INIT_POINTER(nf_ct_timeout_put_hook, ctnl_timeout_put);
616#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
617 return 0;
618
619err_out:
620 unregister_pernet_subsys(&cttimeout_ops);
621 return ret;
622}
623
624static void __exit cttimeout_exit(void)
625{
626 nfnetlink_subsys_unregister(&cttimeout_subsys);
627
628 unregister_pernet_subsys(&cttimeout_ops);
629#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
630 RCU_INIT_POINTER(nf_ct_timeout_find_get_hook, NULL);
631 RCU_INIT_POINTER(nf_ct_timeout_put_hook, NULL);
632 synchronize_rcu();
633#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
634}
635
636module_init(cttimeout_init);
637module_exit(cttimeout_exit);