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