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:1715:255.255.255.255")];
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);
764