xref: /openbmc/linux/net/netfilter/xt_recent.c (revision 84ed8a99) 
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 <linux/vmalloc.h>
33 #include <net/net_namespace.h>
34 #include <net/netns/generic.h>
35 
36 #include <linux/netfilter/x_tables.h>
37 #include <linux/netfilter/xt_recent.h>
38 
39 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
40 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
41 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
42 MODULE_LICENSE("GPL");
43 MODULE_ALIAS("ipt_recent");
44 MODULE_ALIAS("ip6t_recent");
45 
46 static unsigned int ip_list_tot = 100;
47 static unsigned int ip_pkt_list_tot = 20;
48 static unsigned int ip_list_hash_size = 0;
49 static unsigned int ip_list_perms = 0644;
50 static unsigned int ip_list_uid = 0;
51 static unsigned int ip_list_gid = 0;
52 module_param(ip_list_tot, uint, 0400);
53 module_param(ip_pkt_list_tot, uint, 0400);
54 module_param(ip_list_hash_size, uint, 0400);
55 module_param(ip_list_perms, uint, 0400);
56 module_param(ip_list_uid, uint, S_IRUGO | S_IWUSR);
57 module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR);
58 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
59 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)");
60 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
61 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
62 MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
63 MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
64 
65 struct recent_entry {
66 	struct list_head	list;
67 	struct list_head	lru_list;
68 	union nf_inet_addr	addr;
69 	u_int16_t		family;
70 	u_int8_t		ttl;
71 	u_int8_t		index;
72 	u_int16_t		nstamps;
73 	unsigned long		stamps[0];
74 };
75 
76 struct recent_table {
77 	struct list_head	list;
78 	char			name[XT_RECENT_NAME_LEN];
79 	union nf_inet_addr	mask;
80 	unsigned int		refcnt;
81 	unsigned int		entries;
82 	struct list_head	lru_list;
83 	struct list_head	iphash[0];
84 };
85 
86 struct recent_net {
87 	struct list_head	tables;
88 #ifdef CONFIG_PROC_FS
89 	struct proc_dir_entry	*xt_recent;
90 #endif
91 };
92 
93 static int recent_net_id;
94 static inline struct recent_net *recent_pernet(struct net *net)
95 {
96 	return net_generic(net, recent_net_id);
97 }
98 
99 static DEFINE_SPINLOCK(recent_lock);
100 static DEFINE_MUTEX(recent_mutex);
101 
102 #ifdef CONFIG_PROC_FS
103 static const struct file_operations recent_old_fops, recent_mt_fops;
104 #endif
105 
106 static u_int32_t hash_rnd __read_mostly;
107 static bool hash_rnd_inited __read_mostly;
108 
109 static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
110 {
111 	return jhash_1word((__force u32)addr->ip, hash_rnd) &
112 	       (ip_list_hash_size - 1);
113 }
114 
115 static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
116 {
117 	return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
118 	       (ip_list_hash_size - 1);
119 }
120 
121 static struct recent_entry *
122 recent_entry_lookup(const struct recent_table *table,
123 		    const union nf_inet_addr *addrp, u_int16_t family,
124 		    u_int8_t ttl)
125 {
126 	struct recent_entry *e;
127 	unsigned int h;
128 
129 	if (family == NFPROTO_IPV4)
130 		h = recent_entry_hash4(addrp);
131 	else
132 		h = recent_entry_hash6(addrp);
133 
134 	list_for_each_entry(e, &table->iphash[h], list)
135 		if (e->family == family &&
136 		    memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
137 		    (ttl == e->ttl || ttl == 0 || e->ttl == 0))
138 			return e;
139 	return NULL;
140 }
141 
142 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
143 {
144 	list_del(&e->list);
145 	list_del(&e->lru_list);
146 	kfree(e);
147 	t->entries--;
148 }
149 
150 /*
151  * Drop entries with timestamps older then 'time'.
152  */
153 static void recent_entry_reap(struct recent_table *t, unsigned long time)
154 {
155 	struct recent_entry *e;
156 
157 	/*
158 	 * The head of the LRU list is always the oldest entry.
159 	 */
160 	e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
161 
162 	/*
163 	 * The last time stamp is the most recent.
164 	 */
165 	if (time_after(time, e->stamps[e->index-1]))
166 		recent_entry_remove(t, e);
167 }
168 
169 static struct recent_entry *
170 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
171 		  u_int16_t family, u_int8_t ttl)
172 {
173 	struct recent_entry *e;
174 
175 	if (t->entries >= ip_list_tot) {
176 		e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
177 		recent_entry_remove(t, e);
178 	}
179 	e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
180 		    GFP_ATOMIC);
181 	if (e == NULL)
182 		return NULL;
183 	memcpy(&e->addr, addr, sizeof(e->addr));
184 	e->ttl       = ttl;
185 	e->stamps[0] = jiffies;
186 	e->nstamps   = 1;
187 	e->index     = 1;
188 	e->family    = family;
189 	if (family == NFPROTO_IPV4)
190 		list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
191 	else
192 		list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
193 	list_add_tail(&e->lru_list, &t->lru_list);
194 	t->entries++;
195 	return e;
196 }
197 
198 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
199 {
200 	e->index %= ip_pkt_list_tot;
201 	e->stamps[e->index++] = jiffies;
202 	if (e->index > e->nstamps)
203 		e->nstamps = e->index;
204 	list_move_tail(&e->lru_list, &t->lru_list);
205 }
206 
207 static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
208 						const char *name)
209 {
210 	struct recent_table *t;
211 
212 	list_for_each_entry(t, &recent_net->tables, list)
213 		if (!strcmp(t->name, name))
214 			return t;
215 	return NULL;
216 }
217 
218 static void recent_table_flush(struct recent_table *t)
219 {
220 	struct recent_entry *e, *next;
221 	unsigned int i;
222 
223 	for (i = 0; i < ip_list_hash_size; i++)
224 		list_for_each_entry_safe(e, next, &t->iphash[i], list)
225 			recent_entry_remove(t, e);
226 }
227 
228 static bool
229 recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
230 {
231 	struct net *net = dev_net(par->in ? par->in : par->out);
232 	struct recent_net *recent_net = recent_pernet(net);
233 	const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
234 	struct recent_table *t;
235 	struct recent_entry *e;
236 	union nf_inet_addr addr = {}, addr_mask;
237 	u_int8_t ttl;
238 	bool ret = info->invert;
239 
240 	if (par->family == NFPROTO_IPV4) {
241 		const struct iphdr *iph = ip_hdr(skb);
242 
243 		if (info->side == XT_RECENT_DEST)
244 			addr.ip = iph->daddr;
245 		else
246 			addr.ip = iph->saddr;
247 
248 		ttl = iph->ttl;
249 	} else {
250 		const struct ipv6hdr *iph = ipv6_hdr(skb);
251 
252 		if (info->side == XT_RECENT_DEST)
253 			memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
254 		else
255 			memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
256 
257 		ttl = iph->hop_limit;
258 	}
259 
260 	/* use TTL as seen before forwarding */
261 	if (par->out != NULL && skb->sk == NULL)
262 		ttl++;
263 
264 	spin_lock_bh(&recent_lock);
265 	t = recent_table_lookup(recent_net, info->name);
266 
267 	nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
268 
269 	e = recent_entry_lookup(t, &addr_mask, par->family,
270 				(info->check_set & XT_RECENT_TTL) ? ttl : 0);
271 	if (e == NULL) {
272 		if (!(info->check_set & XT_RECENT_SET))
273 			goto out;
274 		e = recent_entry_init(t, &addr_mask, par->family, ttl);
275 		if (e == NULL)
276 			par->hotdrop = true;
277 		ret = !ret;
278 		goto out;
279 	}
280 
281 	if (info->check_set & XT_RECENT_SET)
282 		ret = !ret;
283 	else if (info->check_set & XT_RECENT_REMOVE) {
284 		recent_entry_remove(t, e);
285 		ret = !ret;
286 	} else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
287 		unsigned long time = jiffies - info->seconds * HZ;
288 		unsigned int i, hits = 0;
289 
290 		for (i = 0; i < e->nstamps; i++) {
291 			if (info->seconds && time_after(time, e->stamps[i]))
292 				continue;
293 			if (!info->hit_count || ++hits >= info->hit_count) {
294 				ret = !ret;
295 				break;
296 			}
297 		}
298 
299 		/* info->seconds must be non-zero */
300 		if (info->check_set & XT_RECENT_REAP)
301 			recent_entry_reap(t, time);
302 	}
303 
304 	if (info->check_set & XT_RECENT_SET ||
305 	    (info->check_set & XT_RECENT_UPDATE && ret)) {
306 		recent_entry_update(t, e);
307 		e->ttl = ttl;
308 	}
309 out:
310 	spin_unlock_bh(&recent_lock);
311 	return ret;
312 }
313 
314 static void recent_table_free(void *addr)
315 {
316 	if (is_vmalloc_addr(addr))
317 		vfree(addr);
318 	else
319 		kfree(addr);
320 }
321 
322 static int recent_mt_check(const struct xt_mtchk_param *par,
323 			   const struct xt_recent_mtinfo_v1 *info)
324 {
325 	struct recent_net *recent_net = recent_pernet(par->net);
326 	struct recent_table *t;
327 #ifdef CONFIG_PROC_FS
328 	struct proc_dir_entry *pde;
329 	kuid_t uid;
330 	kgid_t gid;
331 #endif
332 	unsigned int i;
333 	int ret = -EINVAL;
334 	size_t sz;
335 
336 	if (unlikely(!hash_rnd_inited)) {
337 		get_random_bytes(&hash_rnd, sizeof(hash_rnd));
338 		hash_rnd_inited = true;
339 	}
340 	if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
341 		pr_info("Unsupported user space flags (%08x)\n",
342 			info->check_set);
343 		return -EINVAL;
344 	}
345 	if (hweight8(info->check_set &
346 		     (XT_RECENT_SET | XT_RECENT_REMOVE |
347 		      XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
348 		return -EINVAL;
349 	if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
350 	    (info->seconds || info->hit_count ||
351 	    (info->check_set & XT_RECENT_MODIFIERS)))
352 		return -EINVAL;
353 	if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
354 		return -EINVAL;
355 	if (info->hit_count > ip_pkt_list_tot) {
356 		pr_info("hitcount (%u) is larger than "
357 			"packets to be remembered (%u)\n",
358 			info->hit_count, ip_pkt_list_tot);
359 		return -EINVAL;
360 	}
361 	if (info->name[0] == '\0' ||
362 	    strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
363 		return -EINVAL;
364 
365 	mutex_lock(&recent_mutex);
366 	t = recent_table_lookup(recent_net, info->name);
367 	if (t != NULL) {
368 		t->refcnt++;
369 		ret = 0;
370 		goto out;
371 	}
372 
373 	sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
374 	if (sz <= PAGE_SIZE)
375 		t = kzalloc(sz, GFP_KERNEL);
376 	else
377 		t = vzalloc(sz);
378 	if (t == NULL) {
379 		ret = -ENOMEM;
380 		goto out;
381 	}
382 	t->refcnt = 1;
383 
384 	memcpy(&t->mask, &info->mask, sizeof(t->mask));
385 	strcpy(t->name, info->name);
386 	INIT_LIST_HEAD(&t->lru_list);
387 	for (i = 0; i < ip_list_hash_size; i++)
388 		INIT_LIST_HEAD(&t->iphash[i]);
389 #ifdef CONFIG_PROC_FS
390 	uid = make_kuid(&init_user_ns, ip_list_uid);
391 	gid = make_kgid(&init_user_ns, ip_list_gid);
392 	if (!uid_valid(uid) || !gid_valid(gid)) {
393 		recent_table_free(t);
394 		ret = -EINVAL;
395 		goto out;
396 	}
397 	pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
398 		  &recent_mt_fops, t);
399 	if (pde == NULL) {
400 		recent_table_free(t);
401 		ret = -ENOMEM;
402 		goto out;
403 	}
404 	proc_set_user(pde, uid, gid);
405 #endif
406 	spin_lock_bh(&recent_lock);
407 	list_add_tail(&t->list, &recent_net->tables);
408 	spin_unlock_bh(&recent_lock);
409 	ret = 0;
410 out:
411 	mutex_unlock(&recent_mutex);
412 	return ret;
413 }
414 
415 static int recent_mt_check_v0(const struct xt_mtchk_param *par)
416 {
417 	const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
418 	struct xt_recent_mtinfo_v1 info_v1;
419 
420 	/* Copy revision 0 structure to revision 1 */
421 	memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
422 	/* Set default mask to ensure backward compatible behaviour */
423 	memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
424 
425 	return recent_mt_check(par, &info_v1);
426 }
427 
428 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
429 {
430 	return recent_mt_check(par, par->matchinfo);
431 }
432 
433 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
434 {
435 	struct recent_net *recent_net = recent_pernet(par->net);
436 	const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
437 	struct recent_table *t;
438 
439 	mutex_lock(&recent_mutex);
440 	t = recent_table_lookup(recent_net, info->name);
441 	if (--t->refcnt == 0) {
442 		spin_lock_bh(&recent_lock);
443 		list_del(&t->list);
444 		spin_unlock_bh(&recent_lock);
445 #ifdef CONFIG_PROC_FS
446 		if (recent_net->xt_recent != NULL)
447 			remove_proc_entry(t->name, recent_net->xt_recent);
448 #endif
449 		recent_table_flush(t);
450 		recent_table_free(t);
451 	}
452 	mutex_unlock(&recent_mutex);
453 }
454 
455 #ifdef CONFIG_PROC_FS
456 struct recent_iter_state {
457 	const struct recent_table *table;
458 	unsigned int		bucket;
459 };
460 
461 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
462 	__acquires(recent_lock)
463 {
464 	struct recent_iter_state *st = seq->private;
465 	const struct recent_table *t = st->table;
466 	struct recent_entry *e;
467 	loff_t p = *pos;
468 
469 	spin_lock_bh(&recent_lock);
470 
471 	for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
472 		list_for_each_entry(e, &t->iphash[st->bucket], list)
473 			if (p-- == 0)
474 				return e;
475 	return NULL;
476 }
477 
478 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
479 {
480 	struct recent_iter_state *st = seq->private;
481 	const struct recent_table *t = st->table;
482 	const struct recent_entry *e = v;
483 	const struct list_head *head = e->list.next;
484 
485 	while (head == &t->iphash[st->bucket]) {
486 		if (++st->bucket >= ip_list_hash_size)
487 			return NULL;
488 		head = t->iphash[st->bucket].next;
489 	}
490 	(*pos)++;
491 	return list_entry(head, struct recent_entry, list);
492 }
493 
494 static void recent_seq_stop(struct seq_file *s, void *v)
495 	__releases(recent_lock)
496 {
497 	spin_unlock_bh(&recent_lock);
498 }
499 
500 static int recent_seq_show(struct seq_file *seq, void *v)
501 {
502 	const struct recent_entry *e = v;
503 	unsigned int i;
504 
505 	i = (e->index - 1) % ip_pkt_list_tot;
506 	if (e->family == NFPROTO_IPV4)
507 		seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
508 			   &e->addr.ip, e->ttl, e->stamps[i], e->index);
509 	else
510 		seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
511 			   &e->addr.in6, e->ttl, e->stamps[i], e->index);
512 	for (i = 0; i < e->nstamps; i++)
513 		seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
514 	seq_printf(seq, "\n");
515 	return 0;
516 }
517 
518 static const struct seq_operations recent_seq_ops = {
519 	.start		= recent_seq_start,
520 	.next		= recent_seq_next,
521 	.stop		= recent_seq_stop,
522 	.show		= recent_seq_show,
523 };
524 
525 static int recent_seq_open(struct inode *inode, struct file *file)
526 {
527 	struct recent_iter_state *st;
528 
529 	st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
530 	if (st == NULL)
531 		return -ENOMEM;
532 
533 	st->table    = PDE_DATA(inode);
534 	return 0;
535 }
536 
537 static ssize_t
538 recent_mt_proc_write(struct file *file, const char __user *input,
539 		     size_t size, loff_t *loff)
540 {
541 	struct recent_table *t = PDE_DATA(file_inode(file));
542 	struct recent_entry *e;
543 	char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
544 	const char *c = buf;
545 	union nf_inet_addr addr = {};
546 	u_int16_t family;
547 	bool add, succ;
548 
549 	if (size == 0)
550 		return 0;
551 	if (size > sizeof(buf))
552 		size = sizeof(buf);
553 	if (copy_from_user(buf, input, size) != 0)
554 		return -EFAULT;
555 
556 	/* Strict protocol! */
557 	if (*loff != 0)
558 		return -ESPIPE;
559 	switch (*c) {
560 	case '/': /* flush table */
561 		spin_lock_bh(&recent_lock);
562 		recent_table_flush(t);
563 		spin_unlock_bh(&recent_lock);
564 		return size;
565 	case '-': /* remove address */
566 		add = false;
567 		break;
568 	case '+': /* add address */
569 		add = true;
570 		break;
571 	default:
572 		pr_info("Need \"+ip\", \"-ip\" or \"/\"\n");
573 		return -EINVAL;
574 	}
575 
576 	++c;
577 	--size;
578 	if (strnchr(c, size, ':') != NULL) {
579 		family = NFPROTO_IPV6;
580 		succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
581 	} else {
582 		family = NFPROTO_IPV4;
583 		succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
584 	}
585 
586 	if (!succ) {
587 		pr_info("illegal address written to procfs\n");
588 		return -EINVAL;
589 	}
590 
591 	spin_lock_bh(&recent_lock);
592 	e = recent_entry_lookup(t, &addr, family, 0);
593 	if (e == NULL) {
594 		if (add)
595 			recent_entry_init(t, &addr, family, 0);
596 	} else {
597 		if (add)
598 			recent_entry_update(t, e);
599 		else
600 			recent_entry_remove(t, e);
601 	}
602 	spin_unlock_bh(&recent_lock);
603 	/* Note we removed one above */
604 	*loff += size + 1;
605 	return size + 1;
606 }
607 
608 static const struct file_operations recent_mt_fops = {
609 	.open    = recent_seq_open,
610 	.read    = seq_read,
611 	.write   = recent_mt_proc_write,
612 	.release = seq_release_private,
613 	.owner   = THIS_MODULE,
614 	.llseek = seq_lseek,
615 };
616 
617 static int __net_init recent_proc_net_init(struct net *net)
618 {
619 	struct recent_net *recent_net = recent_pernet(net);
620 
621 	recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
622 	if (!recent_net->xt_recent)
623 		return -ENOMEM;
624 	return 0;
625 }
626 
627 static void __net_exit recent_proc_net_exit(struct net *net)
628 {
629 	struct recent_net *recent_net = recent_pernet(net);
630 	struct recent_table *t;
631 
632 	/* recent_net_exit() is called before recent_mt_destroy(). Make sure
633 	 * that the parent xt_recent proc entry is is empty before trying to
634 	 * remove it.
635 	 */
636 	spin_lock_bh(&recent_lock);
637 	list_for_each_entry(t, &recent_net->tables, list)
638 	        remove_proc_entry(t->name, recent_net->xt_recent);
639 
640 	recent_net->xt_recent = NULL;
641 	spin_unlock_bh(&recent_lock);
642 
643 	remove_proc_entry("xt_recent", net->proc_net);
644 }
645 #else
646 static inline int recent_proc_net_init(struct net *net)
647 {
648 	return 0;
649 }
650 
651 static inline void recent_proc_net_exit(struct net *net)
652 {
653 }
654 #endif /* CONFIG_PROC_FS */
655 
656 static int __net_init recent_net_init(struct net *net)
657 {
658 	struct recent_net *recent_net = recent_pernet(net);
659 
660 	INIT_LIST_HEAD(&recent_net->tables);
661 	return recent_proc_net_init(net);
662 }
663 
664 static void __net_exit recent_net_exit(struct net *net)
665 {
666 	recent_proc_net_exit(net);
667 }
668 
669 static struct pernet_operations recent_net_ops = {
670 	.init	= recent_net_init,
671 	.exit	= recent_net_exit,
672 	.id	= &recent_net_id,
673 	.size	= sizeof(struct recent_net),
674 };
675 
676 static struct xt_match recent_mt_reg[] __read_mostly = {
677 	{
678 		.name       = "recent",
679 		.revision   = 0,
680 		.family     = NFPROTO_IPV4,
681 		.match      = recent_mt,
682 		.matchsize  = sizeof(struct xt_recent_mtinfo),
683 		.checkentry = recent_mt_check_v0,
684 		.destroy    = recent_mt_destroy,
685 		.me         = THIS_MODULE,
686 	},
687 	{
688 		.name       = "recent",
689 		.revision   = 0,
690 		.family     = NFPROTO_IPV6,
691 		.match      = recent_mt,
692 		.matchsize  = sizeof(struct xt_recent_mtinfo),
693 		.checkentry = recent_mt_check_v0,
694 		.destroy    = recent_mt_destroy,
695 		.me         = THIS_MODULE,
696 	},
697 	{
698 		.name       = "recent",
699 		.revision   = 1,
700 		.family     = NFPROTO_IPV4,
701 		.match      = recent_mt,
702 		.matchsize  = sizeof(struct xt_recent_mtinfo_v1),
703 		.checkentry = recent_mt_check_v1,
704 		.destroy    = recent_mt_destroy,
705 		.me         = THIS_MODULE,
706 	},
707 	{
708 		.name       = "recent",
709 		.revision   = 1,
710 		.family     = NFPROTO_IPV6,
711 		.match      = recent_mt,
712 		.matchsize  = sizeof(struct xt_recent_mtinfo_v1),
713 		.checkentry = recent_mt_check_v1,
714 		.destroy    = recent_mt_destroy,
715 		.me         = THIS_MODULE,
716 	}
717 };
718 
719 static int __init recent_mt_init(void)
720 {
721 	int err;
722 
723 	if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
724 		return -EINVAL;
725 	ip_list_hash_size = 1 << fls(ip_list_tot);
726 
727 	err = register_pernet_subsys(&recent_net_ops);
728 	if (err)
729 		return err;
730 	err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
731 	if (err)
732 		unregister_pernet_subsys(&recent_net_ops);
733 	return err;
734 }
735 
736 static void __exit recent_mt_exit(void)
737 {
738 	xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
739 	unregister_pernet_subsys(&recent_net_ops);
740 }
741 
742 module_init(recent_mt_init);
743 module_exit(recent_mt_exit);
744