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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
4 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
5 *
6 * This is a replacement of the old ipt_recent module, which carried the
7 * following copyright notice:
8 *
9 * Author: Stephen Frost <sfrost@snowman.net>
10 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
11 */
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13#include <linux/init.h>
14#include <linux/ip.h>
15#include <linux/ipv6.h>
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/proc_fs.h>
19#include <linux/seq_file.h>
20#include <linux/string.h>
21#include <linux/ctype.h>
22#include <linux/list.h>
23#include <linux/random.h>
24#include <linux/jhash.h>
25#include <linux/bitops.h>
26#include <linux/skbuff.h>
27#include <linux/inet.h>
28#include <linux/slab.h>
29#include <linux/vmalloc.h>
30#include <net/net_namespace.h>
31#include <net/netns/generic.h>
32
33#include <linux/netfilter/x_tables.h>
34#include <linux/netfilter/xt_recent.h>
35
36MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
37MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
38MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
39MODULE_LICENSE("GPL");
40MODULE_ALIAS("ipt_recent");
41MODULE_ALIAS("ip6t_recent");
42
43static unsigned int ip_list_tot __read_mostly = 100;
44static unsigned int ip_list_hash_size __read_mostly;
45static unsigned int ip_list_perms __read_mostly = 0644;
46static unsigned int ip_list_uid __read_mostly;
47static unsigned int ip_list_gid __read_mostly;
48module_param(ip_list_tot, uint, 0400);
49module_param(ip_list_hash_size, uint, 0400);
50module_param(ip_list_perms, uint, 0400);
51module_param(ip_list_uid, uint, 0644);
52module_param(ip_list_gid, uint, 0644);
53MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
54MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
55MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
56MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
57MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
58
59/* retained for backwards compatibility */
60static unsigned int ip_pkt_list_tot __read_mostly;
61module_param(ip_pkt_list_tot, uint, 0400);
62MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)");
63
64#define XT_RECENT_MAX_NSTAMPS 256
65
66struct recent_entry {
67 struct list_head list;
68 struct list_head lru_list;
69 union nf_inet_addr addr;
70 u_int16_t family;
71 u_int8_t ttl;
72 u_int8_t index;
73 u_int16_t nstamps;
74 unsigned long stamps[];
75};
76
77struct recent_table {
78 struct list_head list;
79 char name[XT_RECENT_NAME_LEN];
80 union nf_inet_addr mask;
81 unsigned int refcnt;
82 unsigned int entries;
83 u8 nstamps_max_mask;
84 struct list_head lru_list;
85 struct list_head iphash[];
86};
87
88struct recent_net {
89 struct list_head tables;
90#ifdef CONFIG_PROC_FS
91 struct proc_dir_entry *xt_recent;
92#endif
93};
94
95static unsigned int recent_net_id __read_mostly;
96
97static inline struct recent_net *recent_pernet(struct net *net)
98{
99 return net_generic(net, recent_net_id);
100}
101
102static DEFINE_SPINLOCK(recent_lock);
103static DEFINE_MUTEX(recent_mutex);
104
105#ifdef CONFIG_PROC_FS
106static const struct proc_ops recent_mt_proc_ops;
107#endif
108
109static u_int32_t hash_rnd __read_mostly;
110
111static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
112{
113 return jhash_1word((__force u32)addr->ip, hash_rnd) &
114 (ip_list_hash_size - 1);
115}
116
117static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
118{
119 return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
120 (ip_list_hash_size - 1);
121}
122
123static struct recent_entry *
124recent_entry_lookup(const struct recent_table *table,
125 const union nf_inet_addr *addrp, u_int16_t family,
126 u_int8_t ttl)
127{
128 struct recent_entry *e;
129 unsigned int h;
130
131 if (family == NFPROTO_IPV4)
132 h = recent_entry_hash4(addrp);
133 else
134 h = recent_entry_hash6(addrp);
135
136 list_for_each_entry(e, &table->iphash[h], list)
137 if (e->family == family &&
138 memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
139 (ttl == e->ttl || ttl == 0 || e->ttl == 0))
140 return e;
141 return NULL;
142}
143
144static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
145{
146 list_del(&e->list);
147 list_del(&e->lru_list);
148 kfree(e);
149 t->entries--;
150}
151
152/*
153 * Drop entries with timestamps older then 'time'.
154 */
155static void recent_entry_reap(struct recent_table *t, unsigned long time,
156 struct recent_entry *working, bool update)
157{
158 struct recent_entry *e;
159
160 /*
161 * The head of the LRU list is always the oldest entry.
162 */
163 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
164
165 /*
166 * Do not reap the entry which are going to be updated.
167 */
168 if (e == working && update)
169 return;
170
171 /*
172 * The last time stamp is the most recent.
173 */
174 if (time_after(time, e->stamps[e->index-1]))
175 recent_entry_remove(t, e);
176}
177
178static struct recent_entry *
179recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
180 u_int16_t family, u_int8_t ttl)
181{
182 struct recent_entry *e;
183 unsigned int nstamps_max = t->nstamps_max_mask;
184
185 if (t->entries >= ip_list_tot) {
186 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
187 recent_entry_remove(t, e);
188 }
189
190 nstamps_max += 1;
191 e = kmalloc(struct_size(e, stamps, nstamps_max), GFP_ATOMIC);
192 if (e == NULL)
193 return NULL;
194 memcpy(&e->addr, addr, sizeof(e->addr));
195 e->ttl = ttl;
196 e->stamps[0] = jiffies;
197 e->nstamps = 1;
198 e->index = 1;
199 e->family = family;
200 if (family == NFPROTO_IPV4)
201 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
202 else
203 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
204 list_add_tail(&e->lru_list, &t->lru_list);
205 t->entries++;
206 return e;
207}
208
209static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
210{
211 e->index &= t->nstamps_max_mask;
212 e->stamps[e->index++] = jiffies;
213 if (e->index > e->nstamps)
214 e->nstamps = e->index;
215 list_move_tail(&e->lru_list, &t->lru_list);
216}
217
218static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
219 const char *name)
220{
221 struct recent_table *t;
222
223 list_for_each_entry(t, &recent_net->tables, list)
224 if (!strcmp(t->name, name))
225 return t;
226 return NULL;
227}
228
229static void recent_table_flush(struct recent_table *t)
230{
231 struct recent_entry *e, *next;
232 unsigned int i;
233
234 for (i = 0; i < ip_list_hash_size; i++)
235 list_for_each_entry_safe(e, next, &t->iphash[i], list)
236 recent_entry_remove(t, e);
237}
238
239static bool
240recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
241{
242 struct net *net = xt_net(par);
243 struct recent_net *recent_net = recent_pernet(net);
244 const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
245 struct recent_table *t;
246 struct recent_entry *e;
247 union nf_inet_addr addr = {}, addr_mask;
248 u_int8_t ttl;
249 bool ret = info->invert;
250
251 if (xt_family(par) == NFPROTO_IPV4) {
252 const struct iphdr *iph = ip_hdr(skb);
253
254 if (info->side == XT_RECENT_DEST)
255 addr.ip = iph->daddr;
256 else
257 addr.ip = iph->saddr;
258
259 ttl = iph->ttl;
260 } else {
261 const struct ipv6hdr *iph = ipv6_hdr(skb);
262
263 if (info->side == XT_RECENT_DEST)
264 memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
265 else
266 memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
267
268 ttl = iph->hop_limit;
269 }
270
271 /* use TTL as seen before forwarding */
272 if (xt_out(par) != NULL &&
273 (!skb->sk || !net_eq(net, sock_net(skb->sk))))
274 ttl++;
275
276 spin_lock_bh(&recent_lock);
277 t = recent_table_lookup(recent_net, info->name);
278
279 nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
280
281 e = recent_entry_lookup(t, &addr_mask, xt_family(par),
282 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
283 if (e == NULL) {
284 if (!(info->check_set & XT_RECENT_SET))
285 goto out;
286 e = recent_entry_init(t, &addr_mask, xt_family(par), ttl);
287 if (e == NULL)
288 par->hotdrop = true;
289 ret = !ret;
290 goto out;
291 }
292
293 if (info->check_set & XT_RECENT_SET)
294 ret = !ret;
295 else if (info->check_set & XT_RECENT_REMOVE) {
296 recent_entry_remove(t, e);
297 ret = !ret;
298 } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
299 unsigned long time = jiffies - info->seconds * HZ;
300 unsigned int i, hits = 0;
301
302 for (i = 0; i < e->nstamps; i++) {
303 if (info->seconds && time_after(time, e->stamps[i]))
304 continue;
305 if (!info->hit_count || ++hits >= info->hit_count) {
306 ret = !ret;
307 break;
308 }
309 }
310
311 /* info->seconds must be non-zero */
312 if (info->check_set & XT_RECENT_REAP)
313 recent_entry_reap(t, time, e,
314 info->check_set & XT_RECENT_UPDATE && ret);
315 }
316
317 if (info->check_set & XT_RECENT_SET ||
318 (info->check_set & XT_RECENT_UPDATE && ret)) {
319 recent_entry_update(t, e);
320 e->ttl = ttl;
321 }
322out:
323 spin_unlock_bh(&recent_lock);
324 return ret;
325}
326
327static void recent_table_free(void *addr)
328{
329 kvfree(addr);
330}
331
332static int recent_mt_check(const struct xt_mtchk_param *par,
333 const struct xt_recent_mtinfo_v1 *info)
334{
335 struct recent_net *recent_net = recent_pernet(par->net);
336 struct recent_table *t;
337#ifdef CONFIG_PROC_FS
338 struct proc_dir_entry *pde;
339 kuid_t uid;
340 kgid_t gid;
341#endif
342 unsigned int nstamp_mask;
343 unsigned int i;
344 int ret = -EINVAL;
345
346 net_get_random_once(&hash_rnd, sizeof(hash_rnd));
347
348 if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
349 pr_info_ratelimited("Unsupported userspace flags (%08x)\n",
350 info->check_set);
351 return -EINVAL;
352 }
353 if (hweight8(info->check_set &
354 (XT_RECENT_SET | XT_RECENT_REMOVE |
355 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
356 return -EINVAL;
357 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
358 (info->seconds || info->hit_count ||
359 (info->check_set & XT_RECENT_MODIFIERS)))
360 return -EINVAL;
361 if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
362 return -EINVAL;
363 if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
364 pr_info_ratelimited("hitcount (%u) is larger than allowed maximum (%u)\n",
365 info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
366 return -EINVAL;
367 }
368 ret = xt_check_proc_name(info->name, sizeof(info->name));
369 if (ret)
370 return ret;
371
372 if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
373 nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
374 else if (info->hit_count)
375 nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
376 else
377 nstamp_mask = 32 - 1;
378
379 mutex_lock(&recent_mutex);
380 t = recent_table_lookup(recent_net, info->name);
381 if (t != NULL) {
382 if (nstamp_mask > t->nstamps_max_mask) {
383 spin_lock_bh(&recent_lock);
384 recent_table_flush(t);
385 t->nstamps_max_mask = nstamp_mask;
386 spin_unlock_bh(&recent_lock);
387 }
388
389 t->refcnt++;
390 ret = 0;
391 goto out;
392 }
393
394 t = kvzalloc(struct_size(t, iphash, ip_list_hash_size), GFP_KERNEL);
395 if (t == NULL) {
396 ret = -ENOMEM;
397 goto out;
398 }
399 t->refcnt = 1;
400 t->nstamps_max_mask = nstamp_mask;
401
402 memcpy(&t->mask, &info->mask, sizeof(t->mask));
403 strcpy(t->name, info->name);
404 INIT_LIST_HEAD(&t->lru_list);
405 for (i = 0; i < ip_list_hash_size; i++)
406 INIT_LIST_HEAD(&t->iphash[i]);
407#ifdef CONFIG_PROC_FS
408 uid = make_kuid(&init_user_ns, ip_list_uid);
409 gid = make_kgid(&init_user_ns, ip_list_gid);
410 if (!uid_valid(uid) || !gid_valid(gid)) {
411 recent_table_free(t);
412 ret = -EINVAL;
413 goto out;
414 }
415 pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
416 &recent_mt_proc_ops, t);
417 if (pde == NULL) {
418 recent_table_free(t);
419 ret = -ENOMEM;
420 goto out;
421 }
422 proc_set_user(pde, uid, gid);
423#endif
424 spin_lock_bh(&recent_lock);
425 list_add_tail(&t->list, &recent_net->tables);
426 spin_unlock_bh(&recent_lock);
427 ret = 0;
428out:
429 mutex_unlock(&recent_mutex);
430 return ret;
431}
432
433static int recent_mt_check_v0(const struct xt_mtchk_param *par)
434{
435 const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
436 struct xt_recent_mtinfo_v1 info_v1;
437
438 /* Copy revision 0 structure to revision 1 */
439 memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
440 /* Set default mask to ensure backward compatible behaviour */
441 memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
442
443 return recent_mt_check(par, &info_v1);
444}
445
446static int recent_mt_check_v1(const struct xt_mtchk_param *par)
447{
448 return recent_mt_check(par, par->matchinfo);
449}
450
451static void recent_mt_destroy(const struct xt_mtdtor_param *par)
452{
453 struct recent_net *recent_net = recent_pernet(par->net);
454 const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
455 struct recent_table *t;
456
457 mutex_lock(&recent_mutex);
458 t = recent_table_lookup(recent_net, info->name);
459 if (--t->refcnt == 0) {
460 spin_lock_bh(&recent_lock);
461 list_del(&t->list);
462 spin_unlock_bh(&recent_lock);
463#ifdef CONFIG_PROC_FS
464 if (recent_net->xt_recent != NULL)
465 remove_proc_entry(t->name, recent_net->xt_recent);
466#endif
467 recent_table_flush(t);
468 recent_table_free(t);
469 }
470 mutex_unlock(&recent_mutex);
471}
472
473#ifdef CONFIG_PROC_FS
474struct recent_iter_state {
475 const struct recent_table *table;
476 unsigned int bucket;
477};
478
479static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
480 __acquires(recent_lock)
481{
482 struct recent_iter_state *st = seq->private;
483 const struct recent_table *t = st->table;
484 struct recent_entry *e;
485 loff_t p = *pos;
486
487 spin_lock_bh(&recent_lock);
488
489 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
490 list_for_each_entry(e, &t->iphash[st->bucket], list)
491 if (p-- == 0)
492 return e;
493 return NULL;
494}
495
496static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
497{
498 struct recent_iter_state *st = seq->private;
499 const struct recent_table *t = st->table;
500 const struct recent_entry *e = v;
501 const struct list_head *head = e->list.next;
502
503 (*pos)++;
504 while (head == &t->iphash[st->bucket]) {
505 if (++st->bucket >= ip_list_hash_size)
506 return NULL;
507 head = t->iphash[st->bucket].next;
508 }
509 return list_entry(head, struct recent_entry, list);
510}
511
512static void recent_seq_stop(struct seq_file *s, void *v)
513 __releases(recent_lock)
514{
515 spin_unlock_bh(&recent_lock);
516}
517
518static int recent_seq_show(struct seq_file *seq, void *v)
519{
520 const struct recent_entry *e = v;
521 struct recent_iter_state *st = seq->private;
522 const struct recent_table *t = st->table;
523 unsigned int i;
524
525 i = (e->index - 1) & t->nstamps_max_mask;
526
527 if (e->family == NFPROTO_IPV4)
528 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
529 &e->addr.ip, e->ttl, e->stamps[i], e->index);
530 else
531 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
532 &e->addr.in6, e->ttl, e->stamps[i], e->index);
533 for (i = 0; i < e->nstamps; i++)
534 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
535 seq_putc(seq, '\n');
536 return 0;
537}
538
539static const struct seq_operations recent_seq_ops = {
540 .start = recent_seq_start,
541 .next = recent_seq_next,
542 .stop = recent_seq_stop,
543 .show = recent_seq_show,
544};
545
546static int recent_seq_open(struct inode *inode, struct file *file)
547{
548 struct recent_iter_state *st;
549
550 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
551 if (st == NULL)
552 return -ENOMEM;
553
554 st->table = PDE_DATA(inode);
555 return 0;
556}
557
558static ssize_t
559recent_mt_proc_write(struct file *file, const char __user *input,
560 size_t size, loff_t *loff)
561{
562 struct recent_table *t = PDE_DATA(file_inode(file));
563 struct recent_entry *e;
564 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
565 const char *c = buf;
566 union nf_inet_addr addr = {};
567 u_int16_t family;
568 bool add, succ;
569
570 if (size == 0)
571 return 0;
572 if (size > sizeof(buf))
573 size = sizeof(buf);
574 if (copy_from_user(buf, input, size) != 0)
575 return -EFAULT;
576
577 /* Strict protocol! */
578 if (*loff != 0)
579 return -ESPIPE;
580 switch (*c) {
581 case '/': /* flush table */
582 spin_lock_bh(&recent_lock);
583 recent_table_flush(t);
584 spin_unlock_bh(&recent_lock);
585 return size;
586 case '-': /* remove address */
587 add = false;
588 break;
589 case '+': /* add address */
590 add = true;
591 break;
592 default:
593 pr_info_ratelimited("Need \"+ip\", \"-ip\" or \"/\"\n");
594 return -EINVAL;
595 }
596
597 ++c;
598 --size;
599 if (strnchr(c, size, ':') != NULL) {
600 family = NFPROTO_IPV6;
601 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
602 } else {
603 family = NFPROTO_IPV4;
604 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
605 }
606
607 if (!succ)
608 return -EINVAL;
609
610 spin_lock_bh(&recent_lock);
611 e = recent_entry_lookup(t, &addr, family, 0);
612 if (e == NULL) {
613 if (add)
614 recent_entry_init(t, &addr, family, 0);
615 } else {
616 if (add)
617 recent_entry_update(t, e);
618 else
619 recent_entry_remove(t, e);
620 }
621 spin_unlock_bh(&recent_lock);
622 /* Note we removed one above */
623 *loff += size + 1;
624 return size + 1;
625}
626
627static const struct proc_ops recent_mt_proc_ops = {
628 .proc_open = recent_seq_open,
629 .proc_read = seq_read,
630 .proc_write = recent_mt_proc_write,
631 .proc_release = seq_release_private,
632 .proc_lseek = seq_lseek,
633};
634
635static int __net_init recent_proc_net_init(struct net *net)
636{
637 struct recent_net *recent_net = recent_pernet(net);
638
639 recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
640 if (!recent_net->xt_recent)
641 return -ENOMEM;
642 return 0;
643}
644
645static void __net_exit recent_proc_net_exit(struct net *net)
646{
647 struct recent_net *recent_net = recent_pernet(net);
648 struct recent_table *t;
649
650 /* recent_net_exit() is called before recent_mt_destroy(). Make sure
651 * that the parent xt_recent proc entry is empty before trying to
652 * remove it.
653 */
654 spin_lock_bh(&recent_lock);
655 list_for_each_entry(t, &recent_net->tables, list)
656 remove_proc_entry(t->name, recent_net->xt_recent);
657
658 recent_net->xt_recent = NULL;
659 spin_unlock_bh(&recent_lock);
660
661 remove_proc_entry("xt_recent", net->proc_net);
662}
663#else
664static inline int recent_proc_net_init(struct net *net)
665{
666 return 0;
667}
668
669static inline void recent_proc_net_exit(struct net *net)
670{
671}
672#endif /* CONFIG_PROC_FS */
673
674static int __net_init recent_net_init(struct net *net)
675{
676 struct recent_net *recent_net = recent_pernet(net);
677
678 INIT_LIST_HEAD(&recent_net->tables);
679 return recent_proc_net_init(net);
680}
681
682static void __net_exit recent_net_exit(struct net *net)
683{
684 recent_proc_net_exit(net);
685}
686
687static struct pernet_operations recent_net_ops = {
688 .init = recent_net_init,
689 .exit = recent_net_exit,
690 .id = &recent_net_id,
691 .size = sizeof(struct recent_net),
692};
693
694static struct xt_match recent_mt_reg[] __read_mostly = {
695 {
696 .name = "recent",
697 .revision = 0,
698 .family = NFPROTO_IPV4,
699 .match = recent_mt,
700 .matchsize = sizeof(struct xt_recent_mtinfo),
701 .checkentry = recent_mt_check_v0,
702 .destroy = recent_mt_destroy,
703 .me = THIS_MODULE,
704 },
705 {
706 .name = "recent",
707 .revision = 0,
708 .family = NFPROTO_IPV6,
709 .match = recent_mt,
710 .matchsize = sizeof(struct xt_recent_mtinfo),
711 .checkentry = recent_mt_check_v0,
712 .destroy = recent_mt_destroy,
713 .me = THIS_MODULE,
714 },
715 {
716 .name = "recent",
717 .revision = 1,
718 .family = NFPROTO_IPV4,
719 .match = recent_mt,
720 .matchsize = sizeof(struct xt_recent_mtinfo_v1),
721 .checkentry = recent_mt_check_v1,
722 .destroy = recent_mt_destroy,
723 .me = THIS_MODULE,
724 },
725 {
726 .name = "recent",
727 .revision = 1,
728 .family = NFPROTO_IPV6,
729 .match = recent_mt,
730 .matchsize = sizeof(struct xt_recent_mtinfo_v1),
731 .checkentry = recent_mt_check_v1,
732 .destroy = recent_mt_destroy,
733 .me = THIS_MODULE,
734 }
735};
736
737static int __init recent_mt_init(void)
738{
739 int err;
740
741 BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS);
742
743 if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS)
744 return -EINVAL;
745 ip_list_hash_size = 1 << fls(ip_list_tot);
746
747 err = register_pernet_subsys(&recent_net_ops);
748 if (err)
749 return err;
750 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
751 if (err)
752 unregister_pernet_subsys(&recent_net_ops);
753 return err;
754}
755
756static void __exit recent_mt_exit(void)
757{
758 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
759 unregister_pernet_subsys(&recent_net_ops);
760}
761
762module_init(recent_mt_init);
763module_exit(recent_mt_exit);
1/*
2 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
3 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
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.
8 *
9 * This is a replacement of the old ipt_recent module, which carried the
10 * following copyright notice:
11 *
12 * Author: Stephen Frost <sfrost@snowman.net>
13 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
14 */
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16#include <linux/init.h>
17#include <linux/ip.h>
18#include <linux/ipv6.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/proc_fs.h>
22#include <linux/seq_file.h>
23#include <linux/string.h>
24#include <linux/ctype.h>
25#include <linux/list.h>
26#include <linux/random.h>
27#include <linux/jhash.h>
28#include <linux/bitops.h>
29#include <linux/skbuff.h>
30#include <linux/inet.h>
31#include <linux/slab.h>
32#include <net/net_namespace.h>
33#include <net/netns/generic.h>
34
35#include <linux/netfilter/x_tables.h>
36#include <linux/netfilter/xt_recent.h>
37
38MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
39MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
40MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
41MODULE_LICENSE("GPL");
42MODULE_ALIAS("ipt_recent");
43MODULE_ALIAS("ip6t_recent");
44
45static unsigned int ip_list_tot = 100;
46static unsigned int ip_pkt_list_tot = 20;
47static unsigned int ip_list_hash_size = 0;
48static unsigned int ip_list_perms = 0644;
49static unsigned int ip_list_uid = 0;
50static unsigned int ip_list_gid = 0;
51module_param(ip_list_tot, uint, 0400);
52module_param(ip_pkt_list_tot, uint, 0400);
53module_param(ip_list_hash_size, uint, 0400);
54module_param(ip_list_perms, uint, 0400);
55module_param(ip_list_uid, uint, S_IRUGO | S_IWUSR);
56module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR);
57MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
58MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)");
59MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
60MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
61MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
62MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
63
64struct recent_entry {
65 struct list_head list;
66 struct list_head lru_list;
67 union nf_inet_addr addr;
68 u_int16_t family;
69 u_int8_t ttl;
70 u_int8_t index;
71 u_int16_t nstamps;
72 unsigned long stamps[0];
73};
74
75struct recent_table {
76 struct list_head list;
77 char name[XT_RECENT_NAME_LEN];
78 unsigned int refcnt;
79 unsigned int entries;
80 struct list_head lru_list;
81 struct list_head iphash[0];
82};
83
84struct recent_net {
85 struct list_head tables;
86#ifdef CONFIG_PROC_FS
87 struct proc_dir_entry *xt_recent;
88#endif
89};
90
91static int recent_net_id;
92static inline struct recent_net *recent_pernet(struct net *net)
93{
94 return net_generic(net, recent_net_id);
95}
96
97static DEFINE_SPINLOCK(recent_lock);
98static DEFINE_MUTEX(recent_mutex);
99
100#ifdef CONFIG_PROC_FS
101static const struct file_operations recent_old_fops, recent_mt_fops;
102#endif
103
104static u_int32_t hash_rnd __read_mostly;
105static bool hash_rnd_inited __read_mostly;
106
107static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
108{
109 return jhash_1word((__force u32)addr->ip, hash_rnd) &
110 (ip_list_hash_size - 1);
111}
112
113static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
114{
115 return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
116 (ip_list_hash_size - 1);
117}
118
119static struct recent_entry *
120recent_entry_lookup(const struct recent_table *table,
121 const union nf_inet_addr *addrp, u_int16_t family,
122 u_int8_t ttl)
123{
124 struct recent_entry *e;
125 unsigned int h;
126
127 if (family == NFPROTO_IPV4)
128 h = recent_entry_hash4(addrp);
129 else
130 h = recent_entry_hash6(addrp);
131
132 list_for_each_entry(e, &table->iphash[h], list)
133 if (e->family == family &&
134 memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
135 (ttl == e->ttl || ttl == 0 || e->ttl == 0))
136 return e;
137 return NULL;
138}
139
140static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
141{
142 list_del(&e->list);
143 list_del(&e->lru_list);
144 kfree(e);
145 t->entries--;
146}
147
148/*
149 * Drop entries with timestamps older then 'time'.
150 */
151static void recent_entry_reap(struct recent_table *t, unsigned long time)
152{
153 struct recent_entry *e;
154
155 /*
156 * The head of the LRU list is always the oldest entry.
157 */
158 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
159
160 /*
161 * The last time stamp is the most recent.
162 */
163 if (time_after(time, e->stamps[e->index-1]))
164 recent_entry_remove(t, e);
165}
166
167static struct recent_entry *
168recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
169 u_int16_t family, u_int8_t ttl)
170{
171 struct recent_entry *e;
172
173 if (t->entries >= ip_list_tot) {
174 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
175 recent_entry_remove(t, e);
176 }
177 e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
178 GFP_ATOMIC);
179 if (e == NULL)
180 return NULL;
181 memcpy(&e->addr, addr, sizeof(e->addr));
182 e->ttl = ttl;
183 e->stamps[0] = jiffies;
184 e->nstamps = 1;
185 e->index = 1;
186 e->family = family;
187 if (family == NFPROTO_IPV4)
188 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
189 else
190 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
191 list_add_tail(&e->lru_list, &t->lru_list);
192 t->entries++;
193 return e;
194}
195
196static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
197{
198 e->index %= ip_pkt_list_tot;
199 e->stamps[e->index++] = jiffies;
200 if (e->index > e->nstamps)
201 e->nstamps = e->index;
202 list_move_tail(&e->lru_list, &t->lru_list);
203}
204
205static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
206 const char *name)
207{
208 struct recent_table *t;
209
210 list_for_each_entry(t, &recent_net->tables, list)
211 if (!strcmp(t->name, name))
212 return t;
213 return NULL;
214}
215
216static void recent_table_flush(struct recent_table *t)
217{
218 struct recent_entry *e, *next;
219 unsigned int i;
220
221 for (i = 0; i < ip_list_hash_size; i++)
222 list_for_each_entry_safe(e, next, &t->iphash[i], list)
223 recent_entry_remove(t, e);
224}
225
226static bool
227recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
228{
229 struct net *net = dev_net(par->in ? par->in : par->out);
230 struct recent_net *recent_net = recent_pernet(net);
231 const struct xt_recent_mtinfo *info = par->matchinfo;
232 struct recent_table *t;
233 struct recent_entry *e;
234 union nf_inet_addr addr = {};
235 u_int8_t ttl;
236 bool ret = info->invert;
237
238 if (par->family == NFPROTO_IPV4) {
239 const struct iphdr *iph = ip_hdr(skb);
240
241 if (info->side == XT_RECENT_DEST)
242 addr.ip = iph->daddr;
243 else
244 addr.ip = iph->saddr;
245
246 ttl = iph->ttl;
247 } else {
248 const struct ipv6hdr *iph = ipv6_hdr(skb);
249
250 if (info->side == XT_RECENT_DEST)
251 memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
252 else
253 memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
254
255 ttl = iph->hop_limit;
256 }
257
258 /* use TTL as seen before forwarding */
259 if (par->out != NULL && skb->sk == NULL)
260 ttl++;
261
262 spin_lock_bh(&recent_lock);
263 t = recent_table_lookup(recent_net, info->name);
264 e = recent_entry_lookup(t, &addr, par->family,
265 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
266 if (e == NULL) {
267 if (!(info->check_set & XT_RECENT_SET))
268 goto out;
269 e = recent_entry_init(t, &addr, par->family, ttl);
270 if (e == NULL)
271 par->hotdrop = true;
272 ret = !ret;
273 goto out;
274 }
275
276 if (info->check_set & XT_RECENT_SET)
277 ret = !ret;
278 else if (info->check_set & XT_RECENT_REMOVE) {
279 recent_entry_remove(t, e);
280 ret = !ret;
281 } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
282 unsigned long time = jiffies - info->seconds * HZ;
283 unsigned int i, hits = 0;
284
285 for (i = 0; i < e->nstamps; i++) {
286 if (info->seconds && time_after(time, e->stamps[i]))
287 continue;
288 if (!info->hit_count || ++hits >= info->hit_count) {
289 ret = !ret;
290 break;
291 }
292 }
293
294 /* info->seconds must be non-zero */
295 if (info->check_set & XT_RECENT_REAP)
296 recent_entry_reap(t, time);
297 }
298
299 if (info->check_set & XT_RECENT_SET ||
300 (info->check_set & XT_RECENT_UPDATE && ret)) {
301 recent_entry_update(t, e);
302 e->ttl = ttl;
303 }
304out:
305 spin_unlock_bh(&recent_lock);
306 return ret;
307}
308
309static int recent_mt_check(const struct xt_mtchk_param *par)
310{
311 struct recent_net *recent_net = recent_pernet(par->net);
312 const struct xt_recent_mtinfo *info = par->matchinfo;
313 struct recent_table *t;
314#ifdef CONFIG_PROC_FS
315 struct proc_dir_entry *pde;
316#endif
317 unsigned i;
318 int ret = -EINVAL;
319
320 if (unlikely(!hash_rnd_inited)) {
321 get_random_bytes(&hash_rnd, sizeof(hash_rnd));
322 hash_rnd_inited = true;
323 }
324 if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
325 pr_info("Unsupported user space flags (%08x)\n",
326 info->check_set);
327 return -EINVAL;
328 }
329 if (hweight8(info->check_set &
330 (XT_RECENT_SET | XT_RECENT_REMOVE |
331 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
332 return -EINVAL;
333 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
334 (info->seconds || info->hit_count ||
335 (info->check_set & XT_RECENT_MODIFIERS)))
336 return -EINVAL;
337 if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
338 return -EINVAL;
339 if (info->hit_count > ip_pkt_list_tot) {
340 pr_info("hitcount (%u) is larger than "
341 "packets to be remembered (%u)\n",
342 info->hit_count, ip_pkt_list_tot);
343 return -EINVAL;
344 }
345 if (info->name[0] == '\0' ||
346 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
347 return -EINVAL;
348
349 mutex_lock(&recent_mutex);
350 t = recent_table_lookup(recent_net, info->name);
351 if (t != NULL) {
352 t->refcnt++;
353 ret = 0;
354 goto out;
355 }
356
357 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
358 GFP_KERNEL);
359 if (t == NULL) {
360 ret = -ENOMEM;
361 goto out;
362 }
363 t->refcnt = 1;
364 strcpy(t->name, info->name);
365 INIT_LIST_HEAD(&t->lru_list);
366 for (i = 0; i < ip_list_hash_size; i++)
367 INIT_LIST_HEAD(&t->iphash[i]);
368#ifdef CONFIG_PROC_FS
369 pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
370 &recent_mt_fops, t);
371 if (pde == NULL) {
372 kfree(t);
373 ret = -ENOMEM;
374 goto out;
375 }
376 pde->uid = ip_list_uid;
377 pde->gid = ip_list_gid;
378#endif
379 spin_lock_bh(&recent_lock);
380 list_add_tail(&t->list, &recent_net->tables);
381 spin_unlock_bh(&recent_lock);
382 ret = 0;
383out:
384 mutex_unlock(&recent_mutex);
385 return ret;
386}
387
388static void recent_mt_destroy(const struct xt_mtdtor_param *par)
389{
390 struct recent_net *recent_net = recent_pernet(par->net);
391 const struct xt_recent_mtinfo *info = par->matchinfo;
392 struct recent_table *t;
393
394 mutex_lock(&recent_mutex);
395 t = recent_table_lookup(recent_net, info->name);
396 if (--t->refcnt == 0) {
397 spin_lock_bh(&recent_lock);
398 list_del(&t->list);
399 spin_unlock_bh(&recent_lock);
400#ifdef CONFIG_PROC_FS
401 remove_proc_entry(t->name, recent_net->xt_recent);
402#endif
403 recent_table_flush(t);
404 kfree(t);
405 }
406 mutex_unlock(&recent_mutex);
407}
408
409#ifdef CONFIG_PROC_FS
410struct recent_iter_state {
411 const struct recent_table *table;
412 unsigned int bucket;
413};
414
415static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
416 __acquires(recent_lock)
417{
418 struct recent_iter_state *st = seq->private;
419 const struct recent_table *t = st->table;
420 struct recent_entry *e;
421 loff_t p = *pos;
422
423 spin_lock_bh(&recent_lock);
424
425 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
426 list_for_each_entry(e, &t->iphash[st->bucket], list)
427 if (p-- == 0)
428 return e;
429 return NULL;
430}
431
432static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
433{
434 struct recent_iter_state *st = seq->private;
435 const struct recent_table *t = st->table;
436 const struct recent_entry *e = v;
437 const struct list_head *head = e->list.next;
438
439 while (head == &t->iphash[st->bucket]) {
440 if (++st->bucket >= ip_list_hash_size)
441 return NULL;
442 head = t->iphash[st->bucket].next;
443 }
444 (*pos)++;
445 return list_entry(head, struct recent_entry, list);
446}
447
448static void recent_seq_stop(struct seq_file *s, void *v)
449 __releases(recent_lock)
450{
451 spin_unlock_bh(&recent_lock);
452}
453
454static int recent_seq_show(struct seq_file *seq, void *v)
455{
456 const struct recent_entry *e = v;
457 unsigned int i;
458
459 i = (e->index - 1) % ip_pkt_list_tot;
460 if (e->family == NFPROTO_IPV4)
461 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
462 &e->addr.ip, e->ttl, e->stamps[i], e->index);
463 else
464 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
465 &e->addr.in6, e->ttl, e->stamps[i], e->index);
466 for (i = 0; i < e->nstamps; i++)
467 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
468 seq_printf(seq, "\n");
469 return 0;
470}
471
472static const struct seq_operations recent_seq_ops = {
473 .start = recent_seq_start,
474 .next = recent_seq_next,
475 .stop = recent_seq_stop,
476 .show = recent_seq_show,
477};
478
479static int recent_seq_open(struct inode *inode, struct file *file)
480{
481 struct proc_dir_entry *pde = PDE(inode);
482 struct recent_iter_state *st;
483
484 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
485 if (st == NULL)
486 return -ENOMEM;
487
488 st->table = pde->data;
489 return 0;
490}
491
492static ssize_t
493recent_mt_proc_write(struct file *file, const char __user *input,
494 size_t size, loff_t *loff)
495{
496 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
497 struct recent_table *t = pde->data;
498 struct recent_entry *e;
499 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
500 const char *c = buf;
501 union nf_inet_addr addr = {};
502 u_int16_t family;
503 bool add, succ;
504
505 if (size == 0)
506 return 0;
507 if (size > sizeof(buf))
508 size = sizeof(buf);
509 if (copy_from_user(buf, input, size) != 0)
510 return -EFAULT;
511
512 /* Strict protocol! */
513 if (*loff != 0)
514 return -ESPIPE;
515 switch (*c) {
516 case '/': /* flush table */
517 spin_lock_bh(&recent_lock);
518 recent_table_flush(t);
519 spin_unlock_bh(&recent_lock);
520 return size;
521 case '-': /* remove address */
522 add = false;
523 break;
524 case '+': /* add address */
525 add = true;
526 break;
527 default:
528 pr_info("Need \"+ip\", \"-ip\" or \"/\"\n");
529 return -EINVAL;
530 }
531
532 ++c;
533 --size;
534 if (strnchr(c, size, ':') != NULL) {
535 family = NFPROTO_IPV6;
536 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
537 } else {
538 family = NFPROTO_IPV4;
539 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
540 }
541
542 if (!succ) {
543 pr_info("illegal address written to procfs\n");
544 return -EINVAL;
545 }
546
547 spin_lock_bh(&recent_lock);
548 e = recent_entry_lookup(t, &addr, family, 0);
549 if (e == NULL) {
550 if (add)
551 recent_entry_init(t, &addr, family, 0);
552 } else {
553 if (add)
554 recent_entry_update(t, e);
555 else
556 recent_entry_remove(t, e);
557 }
558 spin_unlock_bh(&recent_lock);
559 /* Note we removed one above */
560 *loff += size + 1;
561 return size + 1;
562}
563
564static const struct file_operations recent_mt_fops = {
565 .open = recent_seq_open,
566 .read = seq_read,
567 .write = recent_mt_proc_write,
568 .release = seq_release_private,
569 .owner = THIS_MODULE,
570 .llseek = seq_lseek,
571};
572
573static int __net_init recent_proc_net_init(struct net *net)
574{
575 struct recent_net *recent_net = recent_pernet(net);
576
577 recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
578 if (!recent_net->xt_recent)
579 return -ENOMEM;
580 return 0;
581}
582
583static void __net_exit recent_proc_net_exit(struct net *net)
584{
585 proc_net_remove(net, "xt_recent");
586}
587#else
588static inline int recent_proc_net_init(struct net *net)
589{
590 return 0;
591}
592
593static inline void recent_proc_net_exit(struct net *net)
594{
595}
596#endif /* CONFIG_PROC_FS */
597
598static int __net_init recent_net_init(struct net *net)
599{
600 struct recent_net *recent_net = recent_pernet(net);
601
602 INIT_LIST_HEAD(&recent_net->tables);
603 return recent_proc_net_init(net);
604}
605
606static void __net_exit recent_net_exit(struct net *net)
607{
608 struct recent_net *recent_net = recent_pernet(net);
609
610 BUG_ON(!list_empty(&recent_net->tables));
611 recent_proc_net_exit(net);
612}
613
614static struct pernet_operations recent_net_ops = {
615 .init = recent_net_init,
616 .exit = recent_net_exit,
617 .id = &recent_net_id,
618 .size = sizeof(struct recent_net),
619};
620
621static struct xt_match recent_mt_reg[] __read_mostly = {
622 {
623 .name = "recent",
624 .revision = 0,
625 .family = NFPROTO_IPV4,
626 .match = recent_mt,
627 .matchsize = sizeof(struct xt_recent_mtinfo),
628 .checkentry = recent_mt_check,
629 .destroy = recent_mt_destroy,
630 .me = THIS_MODULE,
631 },
632 {
633 .name = "recent",
634 .revision = 0,
635 .family = NFPROTO_IPV6,
636 .match = recent_mt,
637 .matchsize = sizeof(struct xt_recent_mtinfo),
638 .checkentry = recent_mt_check,
639 .destroy = recent_mt_destroy,
640 .me = THIS_MODULE,
641 },
642};
643
644static int __init recent_mt_init(void)
645{
646 int err;
647
648 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
649 return -EINVAL;
650 ip_list_hash_size = 1 << fls(ip_list_tot);
651
652 err = register_pernet_subsys(&recent_net_ops);
653 if (err)
654 return err;
655 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
656 if (err)
657 unregister_pernet_subsys(&recent_net_ops);
658 return err;
659}
660
661static void __exit recent_mt_exit(void)
662{
663 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
664 unregister_pernet_subsys(&recent_net_ops);
665}
666
667module_init(recent_mt_init);
668module_exit(recent_mt_exit);