1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
4 * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
5 */
6#include <linux/init.h>
7#include <linux/module.h>
8#include <linux/kernel.h>
9#include <linux/rculist.h>
10#include <linux/rculist_nulls.h>
11#include <linux/types.h>
12#include <linux/timer.h>
13#include <linux/security.h>
14#include <linux/skbuff.h>
15#include <linux/errno.h>
16#include <linux/netlink.h>
17#include <linux/spinlock.h>
18#include <linux/interrupt.h>
19#include <linux/slab.h>
20
21#include <linux/netfilter.h>
22#include <net/netlink.h>
23#include <net/netns/generic.h>
24#include <net/sock.h>
25#include <net/netfilter/nf_conntrack.h>
26#include <net/netfilter/nf_conntrack_core.h>
27#include <net/netfilter/nf_conntrack_l4proto.h>
28#include <net/netfilter/nf_conntrack_tuple.h>
29#include <net/netfilter/nf_conntrack_timeout.h>
30
31#include <linux/netfilter/nfnetlink.h>
32#include <linux/netfilter/nfnetlink_cttimeout.h>
33
34static unsigned int nfct_timeout_id __read_mostly;
35
36struct ctnl_timeout {
37 struct list_head head;
38 struct list_head free_head;
39 struct rcu_head rcu_head;
40 refcount_t refcnt;
41 char name[CTNL_TIMEOUT_NAME_MAX];
42
43 /* must be at the end */
44 struct nf_ct_timeout timeout;
45};
46
47struct nfct_timeout_pernet {
48 struct list_head nfct_timeout_list;
49 struct list_head nfct_timeout_freelist;
50};
51
52MODULE_LICENSE("GPL");
53MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
54MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tuning");
55
56static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
57 [CTA_TIMEOUT_NAME] = { .type = NLA_NUL_STRING,
58 .len = CTNL_TIMEOUT_NAME_MAX - 1},
59 [CTA_TIMEOUT_L3PROTO] = { .type = NLA_U16 },
60 [CTA_TIMEOUT_L4PROTO] = { .type = NLA_U8 },
61 [CTA_TIMEOUT_DATA] = { .type = NLA_NESTED },
62};
63
64static struct nfct_timeout_pernet *nfct_timeout_pernet(struct net *net)
65{
66 return net_generic(net, id: nfct_timeout_id);
67}
68
69static int
70ctnl_timeout_parse_policy(void *timeout,
71 const struct nf_conntrack_l4proto *l4proto,
72 struct net *net, const struct nlattr *attr)
73{
74 struct nlattr **tb;
75 int ret = 0;
76
77 tb = kcalloc(l4proto->ctnl_timeout.nlattr_max + 1, sizeof(*tb),
78 GFP_KERNEL);
79
80 if (!tb)
81 return -ENOMEM;
82
83 ret = nla_parse_nested_deprecated(tb,
84 maxtype: l4proto->ctnl_timeout.nlattr_max,
85 nla: attr,
86 policy: l4proto->ctnl_timeout.nla_policy,
87 NULL);
88 if (ret < 0)
89 goto err;
90
91 ret = l4proto->ctnl_timeout.nlattr_to_obj(tb, net, timeout);
92
93err:
94 kfree(objp: tb);
95 return ret;
96}
97
98static int cttimeout_new_timeout(struct sk_buff *skb,
99 const struct nfnl_info *info,
100 const struct nlattr * const cda[])
101{
102 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net: info->net);
103 __u16 l3num;
104 __u8 l4num;
105 const struct nf_conntrack_l4proto *l4proto;
106 struct ctnl_timeout *timeout, *matching = NULL;
107 char *name;
108 int ret;
109
110 if (!cda[CTA_TIMEOUT_NAME] ||
111 !cda[CTA_TIMEOUT_L3PROTO] ||
112 !cda[CTA_TIMEOUT_L4PROTO] ||
113 !cda[CTA_TIMEOUT_DATA])
114 return -EINVAL;
115
116 name = nla_data(nla: cda[CTA_TIMEOUT_NAME]);
117 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
118 l4num = nla_get_u8(nla: cda[CTA_TIMEOUT_L4PROTO]);
119
120 list_for_each_entry(timeout, &pernet->nfct_timeout_list, head) {
121 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
122 continue;
123
124 if (info->nlh->nlmsg_flags & NLM_F_EXCL)
125 return -EEXIST;
126
127 matching = timeout;
128 break;
129 }
130
131 if (matching) {
132 if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
133 /* You cannot replace one timeout policy by another of
134 * different kind, sorry.
135 */
136 if (matching->timeout.l3num != l3num ||
137 matching->timeout.l4proto->l4proto != l4num)
138 return -EINVAL;
139
140 return ctnl_timeout_parse_policy(timeout: &matching->timeout.data,
141 l4proto: matching->timeout.l4proto,
142 net: info->net,
143 attr: cda[CTA_TIMEOUT_DATA]);
144 }
145
146 return -EBUSY;
147 }
148
149 l4proto = nf_ct_l4proto_find(l4proto: l4num);
150
151 /* This protocol is not supportted, skip. */
152 if (l4proto->l4proto != l4num) {
153 ret = -EOPNOTSUPP;
154 goto err_proto_put;
155 }
156
157 timeout = kzalloc(sizeof(struct ctnl_timeout) +
158 l4proto->ctnl_timeout.obj_size, GFP_KERNEL);
159 if (timeout == NULL) {
160 ret = -ENOMEM;
161 goto err_proto_put;
162 }
163
164 ret = ctnl_timeout_parse_policy(timeout: &timeout->timeout.data, l4proto,
165 net: info->net, attr: cda[CTA_TIMEOUT_DATA]);
166 if (ret < 0)
167 goto err;
168
169 strcpy(p: timeout->name, q: nla_data(nla: cda[CTA_TIMEOUT_NAME]));
170 timeout->timeout.l3num = l3num;
171 timeout->timeout.l4proto = l4proto;
172 refcount_set(r: &timeout->refcnt, n: 1);
173 __module_get(THIS_MODULE);
174 list_add_tail_rcu(new: &timeout->head, head: &pernet->nfct_timeout_list);
175
176 return 0;
177err:
178 kfree(objp: timeout);
179err_proto_put:
180 return ret;
181}
182
183static int
184ctnl_timeout_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
185 int event, struct ctnl_timeout *timeout)
186{
187 struct nlmsghdr *nlh;
188 unsigned int flags = portid ? NLM_F_MULTI : 0;
189 const struct nf_conntrack_l4proto *l4proto = timeout->timeout.l4proto;
190 struct nlattr *nest_parms;
191 int ret;
192
193 event = nfnl_msg_type(NFNL_SUBSYS_CTNETLINK_TIMEOUT, msg_type: event);
194 nlh = nfnl_msg_put(skb, portid, seq, type: event, flags, AF_UNSPEC,
195 NFNETLINK_V0, res_id: 0);
196 if (!nlh)
197 goto nlmsg_failure;
198
199 if (nla_put_string(skb, attrtype: CTA_TIMEOUT_NAME, str: timeout->name) ||
200 nla_put_be16(skb, attrtype: CTA_TIMEOUT_L3PROTO,
201 htons(timeout->timeout.l3num)) ||
202 nla_put_u8(skb, attrtype: CTA_TIMEOUT_L4PROTO, value: l4proto->l4proto) ||
203 nla_put_be32(skb, attrtype: CTA_TIMEOUT_USE,
204 htonl(refcount_read(&timeout->refcnt))))
205 goto nla_put_failure;
206
207 nest_parms = nla_nest_start(skb, attrtype: CTA_TIMEOUT_DATA);
208 if (!nest_parms)
209 goto nla_put_failure;
210
211 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, &timeout->timeout.data);
212 if (ret < 0)
213 goto nla_put_failure;
214
215 nla_nest_end(skb, start: nest_parms);
216
217 nlmsg_end(skb, nlh);
218 return skb->len;
219
220nlmsg_failure:
221nla_put_failure:
222 nlmsg_cancel(skb, nlh);
223 return -1;
224}
225
226static int
227ctnl_timeout_dump(struct sk_buff *skb, struct netlink_callback *cb)
228{
229 struct nfct_timeout_pernet *pernet;
230 struct net *net = sock_net(sk: skb->sk);
231 struct ctnl_timeout *cur, *last;
232
233 if (cb->args[2])
234 return 0;
235
236 last = (struct ctnl_timeout *)cb->args[1];
237 if (cb->args[1])
238 cb->args[1] = 0;
239
240 rcu_read_lock();
241 pernet = nfct_timeout_pernet(net);
242 list_for_each_entry_rcu(cur, &pernet->nfct_timeout_list, head) {
243 if (last) {
244 if (cur != last)
245 continue;
246
247 last = NULL;
248 }
249 if (ctnl_timeout_fill_info(skb, NETLINK_CB(cb->skb).portid,
250 seq: cb->nlh->nlmsg_seq,
251 NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
252 event: IPCTNL_MSG_TIMEOUT_NEW, timeout: cur) < 0) {
253 cb->args[1] = (unsigned long)cur;
254 break;
255 }
256 }
257 if (!cb->args[1])
258 cb->args[2] = 1;
259 rcu_read_unlock();
260 return skb->len;
261}
262
263static int cttimeout_get_timeout(struct sk_buff *skb,
264 const struct nfnl_info *info,
265 const struct nlattr * const cda[])
266{
267 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net: info->net);
268 int ret = -ENOENT;
269 char *name;
270 struct ctnl_timeout *cur;
271
272 if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
273 struct netlink_dump_control c = {
274 .dump = ctnl_timeout_dump,
275 };
276 return netlink_dump_start(ssk: info->sk, skb, nlh: info->nlh, control: &c);
277 }
278
279 if (!cda[CTA_TIMEOUT_NAME])
280 return -EINVAL;
281 name = nla_data(nla: cda[CTA_TIMEOUT_NAME]);
282
283 list_for_each_entry(cur, &pernet->nfct_timeout_list, head) {
284 struct sk_buff *skb2;
285
286 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
287 continue;
288
289 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
290 if (skb2 == NULL) {
291 ret = -ENOMEM;
292 break;
293 }
294
295 ret = ctnl_timeout_fill_info(skb: skb2, NETLINK_CB(skb).portid,
296 seq: info->nlh->nlmsg_seq,
297 NFNL_MSG_TYPE(info->nlh->nlmsg_type),
298 event: IPCTNL_MSG_TIMEOUT_NEW, timeout: cur);
299 if (ret <= 0) {
300 kfree_skb(skb: skb2);
301 break;
302 }
303
304 ret = nfnetlink_unicast(skb: skb2, net: info->net, NETLINK_CB(skb).portid);
305 break;
306 }
307
308 return ret;
309}
310
311/* try to delete object, fail if it is still in use. */
312static int ctnl_timeout_try_del(struct net *net, struct ctnl_timeout *timeout)
313{
314 int ret = 0;
315
316 /* We want to avoid races with ctnl_timeout_put. So only when the
317 * current refcnt is 1, we decrease it to 0.
318 */
319 if (refcount_dec_if_one(r: &timeout->refcnt)) {
320 /* We are protected by nfnl mutex. */
321 list_del_rcu(entry: &timeout->head);
322 nf_ct_untimeout(net, timeout: &timeout->timeout);
323 kfree_rcu(timeout, rcu_head);
324 } else {
325 ret = -EBUSY;
326 }
327 return ret;
328}
329
330static int cttimeout_del_timeout(struct sk_buff *skb,
331 const struct nfnl_info *info,
332 const struct nlattr * const cda[])
333{
334 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net: info->net);
335 struct ctnl_timeout *cur, *tmp;
336 int ret = -ENOENT;
337 char *name;
338
339 if (!cda[CTA_TIMEOUT_NAME]) {
340 list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_list,
341 head)
342 ctnl_timeout_try_del(net: info->net, timeout: cur);
343
344 return 0;
345 }
346 name = nla_data(nla: cda[CTA_TIMEOUT_NAME]);
347
348 list_for_each_entry(cur, &pernet->nfct_timeout_list, head) {
349 if (strncmp(cur->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
350 continue;
351
352 ret = ctnl_timeout_try_del(net: info->net, timeout: cur);
353 if (ret < 0)
354 return ret;
355
356 break;
357 }
358 return ret;
359}
360
361static int cttimeout_default_set(struct sk_buff *skb,
362 const struct nfnl_info *info,
363 const struct nlattr * const cda[])
364{
365 const struct nf_conntrack_l4proto *l4proto;
366 __u8 l4num;
367 int ret;
368
369 if (!cda[CTA_TIMEOUT_L4PROTO] ||
370 !cda[CTA_TIMEOUT_DATA])
371 return -EINVAL;
372
373 l4num = nla_get_u8(nla: cda[CTA_TIMEOUT_L4PROTO]);
374 l4proto = nf_ct_l4proto_find(l4proto: l4num);
375
376 /* This protocol is not supported, skip. */
377 if (l4proto->l4proto != l4num) {
378 ret = -EOPNOTSUPP;
379 goto err;
380 }
381
382 ret = ctnl_timeout_parse_policy(NULL, l4proto, net: info->net,
383 attr: cda[CTA_TIMEOUT_DATA]);
384 if (ret < 0)
385 goto err;
386
387 return 0;
388err:
389 return ret;
390}
391
392static int
393cttimeout_default_fill_info(struct net *net, struct sk_buff *skb, u32 portid,
394 u32 seq, u32 type, int event, u16 l3num,
395 const struct nf_conntrack_l4proto *l4proto,
396 const unsigned int *timeouts)
397{
398 struct nlmsghdr *nlh;
399 unsigned int flags = portid ? NLM_F_MULTI : 0;
400 struct nlattr *nest_parms;
401 int ret;
402
403 event = nfnl_msg_type(NFNL_SUBSYS_CTNETLINK_TIMEOUT, msg_type: event);
404 nlh = nfnl_msg_put(skb, portid, seq, type: event, flags, AF_UNSPEC,
405 NFNETLINK_V0, res_id: 0);
406 if (!nlh)
407 goto nlmsg_failure;
408
409 if (nla_put_be16(skb, attrtype: CTA_TIMEOUT_L3PROTO, htons(l3num)) ||
410 nla_put_u8(skb, attrtype: CTA_TIMEOUT_L4PROTO, value: l4proto->l4proto))
411 goto nla_put_failure;
412
413 nest_parms = nla_nest_start(skb, attrtype: CTA_TIMEOUT_DATA);
414 if (!nest_parms)
415 goto nla_put_failure;
416
417 ret = l4proto->ctnl_timeout.obj_to_nlattr(skb, timeouts);
418 if (ret < 0)
419 goto nla_put_failure;
420
421 nla_nest_end(skb, start: nest_parms);
422
423 nlmsg_end(skb, nlh);
424 return skb->len;
425
426nlmsg_failure:
427nla_put_failure:
428 nlmsg_cancel(skb, nlh);
429 return -1;
430}
431
432static int cttimeout_default_get(struct sk_buff *skb,
433 const struct nfnl_info *info,
434 const struct nlattr * const cda[])
435{
436 const struct nf_conntrack_l4proto *l4proto;
437 unsigned int *timeouts = NULL;
438 struct sk_buff *skb2;
439 __u16 l3num;
440 __u8 l4num;
441 int ret;
442
443 if (!cda[CTA_TIMEOUT_L3PROTO] || !cda[CTA_TIMEOUT_L4PROTO])
444 return -EINVAL;
445
446 l3num = ntohs(nla_get_be16(cda[CTA_TIMEOUT_L3PROTO]));
447 l4num = nla_get_u8(nla: cda[CTA_TIMEOUT_L4PROTO]);
448 l4proto = nf_ct_l4proto_find(l4proto: l4num);
449
450 if (l4proto->l4proto != l4num)
451 return -EOPNOTSUPP;
452
453 switch (l4proto->l4proto) {
454 case IPPROTO_ICMP:
455 timeouts = &nf_icmp_pernet(net: info->net)->timeout;
456 break;
457 case IPPROTO_TCP:
458 timeouts = nf_tcp_pernet(net: info->net)->timeouts;
459 break;
460 case IPPROTO_UDP:
461 case IPPROTO_UDPLITE:
462 timeouts = nf_udp_pernet(net: info->net)->timeouts;
463 break;
464 case IPPROTO_ICMPV6:
465 timeouts = &nf_icmpv6_pernet(net: info->net)->timeout;
466 break;
467 case IPPROTO_SCTP:
468#ifdef CONFIG_NF_CT_PROTO_SCTP
469 timeouts = nf_sctp_pernet(net: info->net)->timeouts;
470#endif
471 break;
472 case IPPROTO_GRE:
473#ifdef CONFIG_NF_CT_PROTO_GRE
474 timeouts = nf_gre_pernet(net: info->net)->timeouts;
475#endif
476 break;
477 case 255:
478 timeouts = &nf_generic_pernet(net: info->net)->timeout;
479 break;
480 default:
481 WARN_ONCE(1, "Missing timeouts for proto %d", l4proto->l4proto);
482 break;
483 }
484
485 if (!timeouts)
486 return -EOPNOTSUPP;
487
488 skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
489 if (!skb2)
490 return -ENOMEM;
491
492 ret = cttimeout_default_fill_info(net: info->net, skb: skb2,
493 NETLINK_CB(skb).portid,
494 seq: info->nlh->nlmsg_seq,
495 NFNL_MSG_TYPE(info->nlh->nlmsg_type),
496 event: IPCTNL_MSG_TIMEOUT_DEFAULT_SET,
497 l3num, l4proto, timeouts);
498 if (ret <= 0) {
499 kfree_skb(skb: skb2);
500 return -ENOMEM;
501 }
502
503 return nfnetlink_unicast(skb: skb2, net: info->net, NETLINK_CB(skb).portid);
504}
505
506static struct nf_ct_timeout *ctnl_timeout_find_get(struct net *net,
507 const char *name)
508{
509 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);
510 struct ctnl_timeout *timeout, *matching = NULL;
511
512 list_for_each_entry_rcu(timeout, &pernet->nfct_timeout_list, head) {
513 if (strncmp(timeout->name, name, CTNL_TIMEOUT_NAME_MAX) != 0)
514 continue;
515
516 if (!refcount_inc_not_zero(r: &timeout->refcnt))
517 goto err;
518 matching = timeout;
519 break;
520 }
521err:
522 return matching ? &matching->timeout : NULL;
523}
524
525static void ctnl_timeout_put(struct nf_ct_timeout *t)
526{
527 struct ctnl_timeout *timeout =
528 container_of(t, struct ctnl_timeout, timeout);
529
530 if (refcount_dec_and_test(r: &timeout->refcnt)) {
531 kfree_rcu(timeout, rcu_head);
532 module_put(THIS_MODULE);
533 }
534}
535
536static const struct nfnl_callback cttimeout_cb[IPCTNL_MSG_TIMEOUT_MAX] = {
537 [IPCTNL_MSG_TIMEOUT_NEW] = {
538 .call = cttimeout_new_timeout,
539 .type = NFNL_CB_MUTEX,
540 .attr_count = CTA_TIMEOUT_MAX,
541 .policy = cttimeout_nla_policy
542 },
543 [IPCTNL_MSG_TIMEOUT_GET] = {
544 .call = cttimeout_get_timeout,
545 .type = NFNL_CB_MUTEX,
546 .attr_count = CTA_TIMEOUT_MAX,
547 .policy = cttimeout_nla_policy
548 },
549 [IPCTNL_MSG_TIMEOUT_DELETE] = {
550 .call = cttimeout_del_timeout,
551 .type = NFNL_CB_MUTEX,
552 .attr_count = CTA_TIMEOUT_MAX,
553 .policy = cttimeout_nla_policy
554 },
555 [IPCTNL_MSG_TIMEOUT_DEFAULT_SET] = {
556 .call = cttimeout_default_set,
557 .type = NFNL_CB_MUTEX,
558 .attr_count = CTA_TIMEOUT_MAX,
559 .policy = cttimeout_nla_policy
560 },
561 [IPCTNL_MSG_TIMEOUT_DEFAULT_GET] = {
562 .call = cttimeout_default_get,
563 .type = NFNL_CB_MUTEX,
564 .attr_count = CTA_TIMEOUT_MAX,
565 .policy = cttimeout_nla_policy
566 },
567};
568
569static const struct nfnetlink_subsystem cttimeout_subsys = {
570 .name = "conntrack_timeout",
571 .subsys_id = NFNL_SUBSYS_CTNETLINK_TIMEOUT,
572 .cb_count = IPCTNL_MSG_TIMEOUT_MAX,
573 .cb = cttimeout_cb,
574};
575
576MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_CTNETLINK_TIMEOUT);
577
578static int __net_init cttimeout_net_init(struct net *net)
579{
580 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);
581
582 INIT_LIST_HEAD(list: &pernet->nfct_timeout_list);
583 INIT_LIST_HEAD(list: &pernet->nfct_timeout_freelist);
584
585 return 0;
586}
587
588static void __net_exit cttimeout_net_pre_exit(struct net *net)
589{
590 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);
591 struct ctnl_timeout *cur, *tmp;
592
593 list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_list, head) {
594 list_del_rcu(entry: &cur->head);
595 list_add(new: &cur->free_head, head: &pernet->nfct_timeout_freelist);
596 }
597
598 /* core calls synchronize_rcu() after this */
599}
600
601static void __net_exit cttimeout_net_exit(struct net *net)
602{
603 struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);
604 struct ctnl_timeout *cur, *tmp;
605
606 if (list_empty(head: &pernet->nfct_timeout_freelist))
607 return;
608
609 nf_ct_untimeout(net, NULL);
610
611 list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_freelist, free_head) {
612 list_del(entry: &cur->free_head);
613
614 if (refcount_dec_and_test(r: &cur->refcnt))
615 kfree_rcu(cur, rcu_head);
616 }
617}
618
619static struct pernet_operations cttimeout_ops = {
620 .init = cttimeout_net_init,
621 .pre_exit = cttimeout_net_pre_exit,
622 .exit = cttimeout_net_exit,
623 .id = &nfct_timeout_id,
624 .size = sizeof(struct nfct_timeout_pernet),
625};
626
627static const struct nf_ct_timeout_hooks hooks = {
628 .timeout_find_get = ctnl_timeout_find_get,
629 .timeout_put = ctnl_timeout_put,
630};
631
632static int __init cttimeout_init(void)
633{
634 int ret;
635
636 ret = register_pernet_subsys(&cttimeout_ops);
637 if (ret < 0)
638 return ret;
639
640 ret = nfnetlink_subsys_register(n: &cttimeout_subsys);
641 if (ret < 0) {
642 pr_err("cttimeout_init: cannot register cttimeout with "
643 "nfnetlink.\n");
644 goto err_out;
645 }
646 RCU_INIT_POINTER(nf_ct_timeout_hook, &hooks);
647 return 0;
648
649err_out:
650 unregister_pernet_subsys(&cttimeout_ops);
651 return ret;
652}
653
654static int untimeout(struct nf_conn *ct, void *timeout)
655{
656 struct nf_conn_timeout *timeout_ext = nf_ct_timeout_find(ct);
657
658 if (timeout_ext)
659 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
660
661 return 0;
662}
663
664static void __exit cttimeout_exit(void)
665{
666 nfnetlink_subsys_unregister(n: &cttimeout_subsys);
667
668 unregister_pernet_subsys(&cttimeout_ops);
669 RCU_INIT_POINTER(nf_ct_timeout_hook, NULL);
670
671 nf_ct_iterate_destroy(iter: untimeout, NULL);
672}
673
674module_init(cttimeout_init);
675module_exit(cttimeout_exit);
676

source code of linux/net/netfilter/nfnetlink_cttimeout.c