summaryrefslogtreecommitdiffstats
path: root/net/netfilter/xt_recent.c
blob: d2ff15a2412b3335b016e2598d10cb9e2d31eabe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
/*
 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This is a replacement of the old ipt_recent module, which carried the
 * following copyright notice:
 *
 * Author: Stephen Frost <sfrost@snowman.net>
 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <linux/slab.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_recent.h>

MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_recent");
MODULE_ALIAS("ip6t_recent");

static unsigned int ip_list_tot = 100;
static unsigned int ip_pkt_list_tot = 20;
static unsigned int ip_list_hash_size = 0;
static unsigned int ip_list_perms = 0644;
static unsigned int ip_list_uid = 0;
static unsigned int ip_list_gid = 0;
module_param(ip_list_tot, uint, 0400);
module_param(ip_pkt_list_tot, uint, 0400);
module_param(ip_list_hash_size, uint, 0400);
module_param(ip_list_perms, uint, 0400);
module_param(ip_list_uid, uint, S_IRUGO | S_IWUSR);
module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)");
MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");

struct recent_entry {
	struct list_head	list;
	struct list_head	lru_list;
	union nf_inet_addr	addr;
	u_int16_t		family;
	u_int8_t		ttl;
	u_int8_t		index;
	u_int16_t		nstamps;
	unsigned long		stamps[0];
};

struct recent_table {
	struct list_head	list;
	char			name[XT_RECENT_NAME_LEN];
	unsigned int		refcnt;
	unsigned int		entries;
	struct list_head	lru_list;
	struct list_head	iphash[0];
};

struct recent_net {
	struct list_head	tables;
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry	*xt_recent;
#endif
};

static int recent_net_id;
static inline struct recent_net *recent_pernet(struct net *net)
{
	return net_generic(net, recent_net_id);
}

static DEFINE_SPINLOCK(recent_lock);
static DEFINE_MUTEX(recent_mutex);

#ifdef CONFIG_PROC_FS
static const struct file_operations recent_old_fops, recent_mt_fops;
#endif

static u_int32_t hash_rnd __read_mostly;
static bool hash_rnd_inited __read_mostly;

static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
{
	return jhash_1word((__force u32)addr->ip, hash_rnd) &
	       (ip_list_hash_size - 1);
}

static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
{
	return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
	       (ip_list_hash_size - 1);
}

static struct recent_entry *
recent_entry_lookup(const struct recent_table *table,
		    const union nf_inet_addr *addrp, u_int16_t family,
		    u_int8_t ttl)
{
	struct recent_entry *e;
	unsigned int h;

	if (family == NFPROTO_IPV4)
		h = recent_entry_hash4(addrp);
	else
		h = recent_entry_hash6(addrp);

	list_for_each_entry(e, &table->iphash[h], list)
		if (e->family == family &&
		    memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
		    (ttl == e->ttl || ttl == 0 || e->ttl == 0))
			return e;
	return NULL;
}

static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
{
	list_del(&e->list);
	list_del(&e->lru_list);
	kfree(e);
	t->entries--;
}

/*
 * Drop entries with timestamps older then 'time'.
 */
static void recent_entry_reap(struct recent_table *t, unsigned long time)
{
	struct recent_entry *e;

	/*
	 * The head of the LRU list is always the oldest entry.
	 */
	e = list_entry(t->lru_list.next, struct recent_entry, lru_list);

	/*
	 * The last time stamp is the most recent.
	 */
	if (time_after(time, e->stamps[e->index-1]))
		recent_entry_remove(t, e);
}

static struct recent_entry *
recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
		  u_int16_t family, u_int8_t ttl)
{
	struct recent_entry *e;

	if (t->entries >= ip_list_tot) {
		e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
		recent_entry_remove(t, e);
	}
	e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
		    GFP_ATOMIC);
	if (e == NULL)
		return NULL;
	memcpy(&e->addr, addr, sizeof(e->addr));
	e->ttl       = ttl;
	e->stamps[0] = jiffies;
	e->nstamps   = 1;
	e->index     = 1;
	e->family    = family;
	if (family == NFPROTO_IPV4)
		list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
	else
		list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
	list_add_tail(&e->lru_list, &t->lru_list);
	t->entries++;
	return e;
}

static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
{
	e->index %= ip_pkt_list_tot;
	e->stamps[e->index++] = jiffies;
	if (e->index > e->nstamps)
		e->nstamps = e->index;
	list_move_tail(&e->lru_list, &t->lru_list);
}

static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
						const char *name)
{
	struct recent_table *t;

	list_for_each_entry(t, &recent_net->tables, list)
		if (!strcmp(t->name, name))
			return t;
	return NULL;
}

static void recent_table_flush(struct recent_table *t)
{
	struct recent_entry *e, *next;
	unsigned int i;

	for (i = 0; i < ip_list_hash_size; i++)
		list_for_each_entry_safe(e, next, &t->iphash[i], list)
			recent_entry_remove(t, e);
}

static bool
recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	struct net *net = dev_net(par->in ? par->in : par->out);
	struct recent_net *recent_net = recent_pernet(net);
	const struct xt_recent_mtinfo *info = par->matchinfo;
	struct recent_table *t;
	struct recent_entry *e;
	union nf_inet_addr addr = {};
	u_int8_t ttl;
	bool ret = info->invert;

	if (par->family == NFPROTO_IPV4) {
		const struct iphdr *iph = ip_hdr(skb);

		if (info->side == XT_RECENT_DEST)
			addr.ip = iph->daddr;
		else
			addr.ip = iph->saddr;

		ttl = iph->ttl;
	} else {
		const struct ipv6hdr *iph = ipv6_hdr(skb);

		if (info->side == XT_RECENT_DEST)
			memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
		else
			memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));

		ttl = iph->hop_limit;
	}

	/* use TTL as seen before forwarding */
	if (par->out != NULL && skb->sk == NULL)
		ttl++;

	spin_lock_bh(&recent_lock);
	t = recent_table_lookup(recent_net, info->name);
	e = recent_entry_lookup(t, &addr, par->family,
				(info->check_set & XT_RECENT_TTL) ? ttl : 0);
	if (e == NULL) {
		if (!(info->check_set & XT_RECENT_SET))
			goto out;
		e = recent_entry_init(t, &addr, par->family, ttl);
		if (e == NULL)
			par->hotdrop = true;
		ret = !ret;
		goto out;
	}

	if (info->check_set & XT_RECENT_SET)
		ret = !ret;
	else if (info->check_set & XT_RECENT_REMOVE) {
		recent_entry_remove(t, e);
		ret = !ret;
	} else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
		unsigned long time = jiffies - info->seconds * HZ;
		unsigned int i, hits = 0;

		for (i = 0; i < e->nstamps; i++) {
			if (info->seconds && time_after(time, e->stamps[i]))
				continue;
			if (!info->hit_count || ++hits >= info->hit_count) {
				ret = !ret;
				break;
			}
		}

		/* info->seconds must be non-zero */
		if (info->check_set & XT_RECENT_REAP)
			recent_entry_reap(t, time);
	}

	if (info->check_set & XT_RECENT_SET ||
	    (info->check_set & XT_RECENT_UPDATE && ret)) {
		recent_entry_update(t, e);
		e->ttl = ttl;
	}
out:
	spin_unlock_bh(&recent_lock);
	return ret;
}

static int recent_mt_check(const struct xt_mtchk_param *par)
{
	struct recent_net *recent_net = recent_pernet(par->net);
	const struct xt_recent_mtinfo *info = par->matchinfo;
	struct recent_table *t;
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry *pde;
#endif
	unsigned i;
	int ret = -EINVAL;

	if (unlikely(!hash_rnd_inited)) {
		get_random_bytes(&hash_rnd, sizeof(hash_rnd));
		hash_rnd_inited = true;
	}
	if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
		pr_info("Unsupported user space flags (%08x)\n",
			info->check_set);
		return -EINVAL;
	}
	if (hweight8(info->check_set &
		     (XT_RECENT_SET | XT_RECENT_REMOVE |
		      XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
		return -EINVAL;
	if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
	    (info->seconds || info->hit_count ||
	    (info->check_set & XT_RECENT_MODIFIERS)))
		return -EINVAL;
	if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
		return -EINVAL;
	if (info->hit_count > ip_pkt_list_tot) {
		pr_info("hitcount (%u) is larger than "
			"packets to be remembered (%u)\n",
			info->hit_count, ip_pkt_list_tot);
		return -EINVAL;
	}
	if (info->name[0] == '\0' ||
	    strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
		return -EINVAL;

	mutex_lock(&recent_mutex);
	t = recent_table_lookup(recent_net, info->name);
	if (t != NULL) {
		t->refcnt++;
		ret = 0;
		goto out;
	}

	t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
		    GFP_KERNEL);
	if (t == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	t->refcnt = 1;
	strcpy(t->name, info->name);
	INIT_LIST_HEAD(&t->lru_list);
	for (i = 0; i < ip_list_hash_size; i++)
		INIT_LIST_HEAD(&t->iphash[i]);
#ifdef CONFIG_PROC_FS
	pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
		  &recent_mt_fops, t);
	if (pde == NULL) {
		kfree(t);
		ret = -ENOMEM;
		goto out;
	}
	pde->uid = ip_list_uid;
	pde->gid = ip_list_gid;
#endif
	spin_lock_bh(&recent_lock);
	list_add_tail(&t->list, &recent_net->tables);
	spin_unlock_bh(&recent_lock);
	ret = 0;
out:
	mutex_unlock(&recent_mutex);
	return ret;
}

static void recent_mt_destroy(const struct xt_mtdtor_param *par)
{
	struct recent_net *recent_net = recent_pernet(par->net);
	const struct xt_recent_mtinfo *info = par->matchinfo;
	struct recent_table *t;

	mutex_lock(&recent_mutex);
	t = recent_table_lookup(recent_net, info->name);
	if (--t->refcnt == 0) {
		spin_lock_bh(&recent_lock);
		list_del(&t->list);
		spin_unlock_bh(&recent_lock);
#ifdef CONFIG_PROC_FS
		remove_proc_entry(t->name, recent_net->xt_recent);
#endif
		recent_table_flush(t);
		kfree(t);
	}
	mutex_unlock(&recent_mutex);
}

#ifdef CONFIG_PROC_FS
struct recent_iter_state {
	const struct recent_table *table;
	unsigned int		bucket;
};

static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(recent_lock)
{
	struct recent_iter_state *st = seq->private;
	const struct recent_table *t = st->table;
	struct recent_entry *e;
	loff_t p = *pos;

	spin_lock_bh(&recent_lock);

	for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
		list_for_each_entry(e, &t->iphash[st->bucket], list)
			if (p-- == 0)
				return e;
	return NULL;
}

static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct recent_iter_state *st = seq->private;
	const struct recent_table *t = st->table;
	const struct recent_entry *e = v;
	const struct list_head *head = e->list.next;

	while (head == &t->iphash[st->bucket]) {
		if (++st->bucket >= ip_list_hash_size)
			return NULL;
		head = t->iphash[st->bucket].next;
	}
	(*pos)++;
	return list_entry(head, struct recent_entry, list);
}

static void recent_seq_stop(struct seq_file *s, void *v)
	__releases(recent_lock)
{
	spin_unlock_bh(&recent_lock);
}

static int recent_seq_show(struct seq_file *seq, void *v)
{
	const struct recent_entry *e = v;
	unsigned int i;

	i = (e->index - 1) % ip_pkt_list_tot;
	if (e->family == NFPROTO_IPV4)
		seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
			   &e->addr.ip, e->ttl, e->stamps[i], e->index);
	else
		seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
			   &e->addr.in6, e->ttl, e->stamps[i], e->index);
	for (i = 0; i < e->nstamps; i++)
		seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
	seq_printf(seq, "\n");
	return 0;
}

static const struct seq_operations recent_seq_ops = {
	.start		= recent_seq_start,
	.next		= recent_seq_next,
	.stop		= recent_seq_stop,
	.show		= recent_seq_show,
};

static int recent_seq_open(struct inode *inode, struct file *file)
{
	struct proc_dir_entry *pde = PDE(inode);
	struct recent_iter_state *st;

	st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
	if (st == NULL)
		return -ENOMEM;

	st->table    = pde->data;
	return 0;
}

static ssize_t
recent_mt_proc_write(struct file *file, const char __user *input,
		     size_t size, loff_t *loff)
{
	const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
	struct recent_table *t = pde->data;
	struct recent_entry *e;
	char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
	const char *c = buf;
	union nf_inet_addr addr = {};
	u_int16_t family;
	bool add, succ;

	if (size == 0)
		return 0;
	if (size > sizeof(buf))
		size = sizeof(buf);
	if (copy_from_user(buf, input, size) != 0)
		return -EFAULT;

	/* Strict protocol! */
	if (*loff != 0)
		return -ESPIPE;
	switch (*c) {
	case '/': /* flush table */
		spin_lock_bh(&recent_lock);
		recent_table_flush(t);
		spin_unlock_bh(&recent_lock);
		return size;
	case '-': /* remove address */
		add = false;
		break;
	case '+': /* add address */
		add = true;
		break;
	default:
		pr_info("Need \"+ip\", \"-ip\" or \"/\"\n");
		return -EINVAL;
	}

	++c;
	--size;
	if (strnchr(c, size, ':') != NULL) {
		family = NFPROTO_IPV6;
		succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
	} else {
		family = NFPROTO_IPV4;
		succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
	}

	if (!succ) {
		pr_info("illegal address written to procfs\n");
		return -EINVAL;
	}

	spin_lock_bh(&recent_lock);
	e = recent_entry_lookup(t, &addr, family, 0);
	if (e == NULL) {
		if (add)
			recent_entry_init(t, &addr, family, 0);
	} else {
		if (add)
			recent_entry_update(t, e);
		else
			recent_entry_remove(t, e);
	}
	spin_unlock_bh(&recent_lock);
	/* Note we removed one above */
	*loff += size + 1;
	return size + 1;
}

static const struct file_operations recent_mt_fops = {
	.open    = recent_seq_open,
	.read    = seq_read,
	.write   = recent_mt_proc_write,
	.release = seq_release_private,
	.owner   = THIS_MODULE,
	.llseek = seq_lseek,
};

static int __net_init recent_proc_net_init(struct net *net)
{
	struct recent_net *recent_net = recent_pernet(net);

	recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
	if (!recent_net->xt_recent)
		return -ENOMEM;
	return 0;
}

static void __net_exit recent_proc_net_exit(struct net *net)
{
	proc_net_remove(net, "xt_recent");
}
#else
static inline int recent_proc_net_init(struct net *net)
{
	return 0;
}

static inline void recent_proc_net_exit(struct net *net)
{
}
#endif /* CONFIG_PROC_FS */

static int __net_init recent_net_init(struct net *net)
{
	struct recent_net *recent_net = recent_pernet(net);

	INIT_LIST_HEAD(&recent_net->tables);
	return recent_proc_net_init(net);
}

static void __net_exit recent_net_exit(struct net *net)
{
	struct recent_net *recent_net = recent_pernet(net);

	BUG_ON(!list_empty(&recent_net->tables));
	recent_proc_net_exit(net);
}

static struct pernet_operations recent_net_ops = {
	.init	= recent_net_init,
	.exit	= recent_net_exit,
	.id	= &recent_net_id,
	.size	= sizeof(struct recent_net),
};

static struct xt_match recent_mt_reg[] __read_mostly = {
	{
		.name       = "recent",
		.revision   = 0,
		.family     = NFPROTO_IPV4,
		.match      = recent_mt,
		.matchsize  = sizeof(struct xt_recent_mtinfo),
		.checkentry = recent_mt_check,
		.destroy    = recent_mt_destroy,
		.me         = THIS_MODULE,
	},
	{
		.name       = "recent",
		.revision   = 0,
		.family     = NFPROTO_IPV6,
		.match      = recent_mt,
		.matchsize  = sizeof(struct xt_recent_mtinfo),
		.checkentry = recent_mt_check,
		.destroy    = recent_mt_destroy,
		.me         = THIS_MODULE,
	},
};

static int __init recent_mt_init(void)
{
	int err;

	if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
		return -EINVAL;
	ip_list_hash_size = 1 << fls(ip_list_tot);

	err = register_pernet_subsys(&recent_net_ops);
	if (err)
		return err;
	err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
	if (err)
		unregister_pernet_subsys(&recent_net_ops);
	return err;
}

static void __exit recent_mt_exit(void)
{
	xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
	unregister_pernet_subsys(&recent_net_ops);
}

module_init(recent_mt_init);
module_exit(recent_mt_exit);