Version:  2.0.40 2.2.26 2.4.37 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19

Linux/net/netfilter/xt_recent.c

  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 __read_mostly = 100;
 47 static unsigned int ip_list_hash_size __read_mostly;
 48 static unsigned int ip_list_perms __read_mostly = 0644;
 49 static unsigned int ip_list_uid __read_mostly;
 50 static unsigned int ip_list_gid __read_mostly;
 51 module_param(ip_list_tot, uint, 0400);
 52 module_param(ip_list_hash_size, uint, 0400);
 53 module_param(ip_list_perms, uint, 0400);
 54 module_param(ip_list_uid, uint, S_IRUGO | S_IWUSR);
 55 module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR);
 56 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
 57 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
 58 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
 59 MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
 60 MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
 61 
 62 /* retained for backwards compatibility */
 63 static unsigned int ip_pkt_list_tot __read_mostly;
 64 module_param(ip_pkt_list_tot, uint, 0400);
 65 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP address to remember (max. 255)");
 66 
 67 #define XT_RECENT_MAX_NSTAMPS   256
 68 
 69 struct recent_entry {
 70         struct list_head        list;
 71         struct list_head        lru_list;
 72         union nf_inet_addr      addr;
 73         u_int16_t               family;
 74         u_int8_t                ttl;
 75         u_int8_t                index;
 76         u_int16_t               nstamps;
 77         unsigned long           stamps[0];
 78 };
 79 
 80 struct recent_table {
 81         struct list_head        list;
 82         char                    name[XT_RECENT_NAME_LEN];
 83         union nf_inet_addr      mask;
 84         unsigned int            refcnt;
 85         unsigned int            entries;
 86         u8                      nstamps_max_mask;
 87         struct list_head        lru_list;
 88         struct list_head        iphash[0];
 89 };
 90 
 91 struct recent_net {
 92         struct list_head        tables;
 93 #ifdef CONFIG_PROC_FS
 94         struct proc_dir_entry   *xt_recent;
 95 #endif
 96 };
 97 
 98 static int recent_net_id __read_mostly;
 99 
100 static inline struct recent_net *recent_pernet(struct net *net)
101 {
102         return net_generic(net, recent_net_id);
103 }
104 
105 static DEFINE_SPINLOCK(recent_lock);
106 static DEFINE_MUTEX(recent_mutex);
107 
108 #ifdef CONFIG_PROC_FS
109 static const struct file_operations recent_old_fops, recent_mt_fops;
110 #endif
111 
112 static u_int32_t hash_rnd __read_mostly;
113 static bool hash_rnd_inited __read_mostly;
114 
115 static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
116 {
117         return jhash_1word((__force u32)addr->ip, hash_rnd) &
118                (ip_list_hash_size - 1);
119 }
120 
121 static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
122 {
123         return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
124                (ip_list_hash_size - 1);
125 }
126 
127 static struct recent_entry *
128 recent_entry_lookup(const struct recent_table *table,
129                     const union nf_inet_addr *addrp, u_int16_t family,
130                     u_int8_t ttl)
131 {
132         struct recent_entry *e;
133         unsigned int h;
134 
135         if (family == NFPROTO_IPV4)
136                 h = recent_entry_hash4(addrp);
137         else
138                 h = recent_entry_hash6(addrp);
139 
140         list_for_each_entry(e, &table->iphash[h], list)
141                 if (e->family == family &&
142                     memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
143                     (ttl == e->ttl || ttl == 0 || e->ttl == 0))
144                         return e;
145         return NULL;
146 }
147 
148 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
149 {
150         list_del(&e->list);
151         list_del(&e->lru_list);
152         kfree(e);
153         t->entries--;
154 }
155 
156 /*
157  * Drop entries with timestamps older then 'time'.
158  */
159 static void recent_entry_reap(struct recent_table *t, unsigned long time)
160 {
161         struct recent_entry *e;
162 
163         /*
164          * The head of the LRU list is always the oldest entry.
165          */
166         e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
167 
168         /*
169          * The last time stamp is the most recent.
170          */
171         if (time_after(time, e->stamps[e->index-1]))
172                 recent_entry_remove(t, e);
173 }
174 
175 static struct recent_entry *
176 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
177                   u_int16_t family, u_int8_t ttl)
178 {
179         struct recent_entry *e;
180         unsigned int nstamps_max = t->nstamps_max_mask;
181 
182         if (t->entries >= ip_list_tot) {
183                 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
184                 recent_entry_remove(t, e);
185         }
186 
187         nstamps_max += 1;
188         e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * nstamps_max,
189                     GFP_ATOMIC);
190         if (e == NULL)
191                 return NULL;
192         memcpy(&e->addr, addr, sizeof(e->addr));
193         e->ttl       = ttl;
194         e->stamps[0] = jiffies;
195         e->nstamps   = 1;
196         e->index     = 1;
197         e->family    = family;
198         if (family == NFPROTO_IPV4)
199                 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
200         else
201                 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
202         list_add_tail(&e->lru_list, &t->lru_list);
203         t->entries++;
204         return e;
205 }
206 
207 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
208 {
209         e->index &= t->nstamps_max_mask;
210         e->stamps[e->index++] = jiffies;
211         if (e->index > e->nstamps)
212                 e->nstamps = e->index;
213         list_move_tail(&e->lru_list, &t->lru_list);
214 }
215 
216 static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
217                                                 const char *name)
218 {
219         struct recent_table *t;
220 
221         list_for_each_entry(t, &recent_net->tables, list)
222                 if (!strcmp(t->name, name))
223                         return t;
224         return NULL;
225 }
226 
227 static void recent_table_flush(struct recent_table *t)
228 {
229         struct recent_entry *e, *next;
230         unsigned int i;
231 
232         for (i = 0; i < ip_list_hash_size; i++)
233                 list_for_each_entry_safe(e, next, &t->iphash[i], list)
234                         recent_entry_remove(t, e);
235 }
236 
237 static bool
238 recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
239 {
240         struct net *net = dev_net(par->in ? par->in : par->out);
241         struct recent_net *recent_net = recent_pernet(net);
242         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
243         struct recent_table *t;
244         struct recent_entry *e;
245         union nf_inet_addr addr = {}, addr_mask;
246         u_int8_t ttl;
247         bool ret = info->invert;
248 
249         if (par->family == NFPROTO_IPV4) {
250                 const struct iphdr *iph = ip_hdr(skb);
251 
252                 if (info->side == XT_RECENT_DEST)
253                         addr.ip = iph->daddr;
254                 else
255                         addr.ip = iph->saddr;
256 
257                 ttl = iph->ttl;
258         } else {
259                 const struct ipv6hdr *iph = ipv6_hdr(skb);
260 
261                 if (info->side == XT_RECENT_DEST)
262                         memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
263                 else
264                         memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
265 
266                 ttl = iph->hop_limit;
267         }
268 
269         /* use TTL as seen before forwarding */
270         if (par->out != NULL && skb->sk == NULL)
271                 ttl++;
272 
273         spin_lock_bh(&recent_lock);
274         t = recent_table_lookup(recent_net, info->name);
275 
276         nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
277 
278         e = recent_entry_lookup(t, &addr_mask, par->family,
279                                 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
280         if (e == NULL) {
281                 if (!(info->check_set & XT_RECENT_SET))
282                         goto out;
283                 e = recent_entry_init(t, &addr_mask, par->family, ttl);
284                 if (e == NULL)
285                         par->hotdrop = true;
286                 ret = !ret;
287                 goto out;
288         }
289 
290         if (info->check_set & XT_RECENT_SET)
291                 ret = !ret;
292         else if (info->check_set & XT_RECENT_REMOVE) {
293                 recent_entry_remove(t, e);
294                 ret = !ret;
295         } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
296                 unsigned long time = jiffies - info->seconds * HZ;
297                 unsigned int i, hits = 0;
298 
299                 for (i = 0; i < e->nstamps; i++) {
300                         if (info->seconds && time_after(time, e->stamps[i]))
301                                 continue;
302                         if (!info->hit_count || ++hits >= info->hit_count) {
303                                 ret = !ret;
304                                 break;
305                         }
306                 }
307 
308                 /* info->seconds must be non-zero */
309                 if (info->check_set & XT_RECENT_REAP)
310                         recent_entry_reap(t, time);
311         }
312 
313         if (info->check_set & XT_RECENT_SET ||
314             (info->check_set & XT_RECENT_UPDATE && ret)) {
315                 recent_entry_update(t, e);
316                 e->ttl = ttl;
317         }
318 out:
319         spin_unlock_bh(&recent_lock);
320         return ret;
321 }
322 
323 static void recent_table_free(void *addr)
324 {
325         kvfree(addr);
326 }
327 
328 static int recent_mt_check(const struct xt_mtchk_param *par,
329                            const struct xt_recent_mtinfo_v1 *info)
330 {
331         struct recent_net *recent_net = recent_pernet(par->net);
332         struct recent_table *t;
333 #ifdef CONFIG_PROC_FS
334         struct proc_dir_entry *pde;
335         kuid_t uid;
336         kgid_t gid;
337 #endif
338         unsigned int nstamp_mask;
339         unsigned int i;
340         int ret = -EINVAL;
341         size_t sz;
342 
343         if (unlikely(!hash_rnd_inited)) {
344                 get_random_bytes(&hash_rnd, sizeof(hash_rnd));
345                 hash_rnd_inited = true;
346         }
347         if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
348                 pr_info("Unsupported user space flags (%08x)\n",
349                         info->check_set);
350                 return -EINVAL;
351         }
352         if (hweight8(info->check_set &
353                      (XT_RECENT_SET | XT_RECENT_REMOVE |
354                       XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
355                 return -EINVAL;
356         if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
357             (info->seconds || info->hit_count ||
358             (info->check_set & XT_RECENT_MODIFIERS)))
359                 return -EINVAL;
360         if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
361                 return -EINVAL;
362         if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
363                 pr_info("hitcount (%u) is larger than allowed maximum (%u)\n",
364                         info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
365                 return -EINVAL;
366         }
367         if (info->name[0] == '\0' ||
368             strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
369                 return -EINVAL;
370 
371         if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
372                 nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
373         else if (info->hit_count)
374                 nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
375         else
376                 nstamp_mask = 32 - 1;
377 
378         mutex_lock(&recent_mutex);
379         t = recent_table_lookup(recent_net, info->name);
380         if (t != NULL) {
381                 if (info->hit_count > t->nstamps_max_mask) {
382                         pr_info("hitcount (%u) is larger than packets to be remembered (%u) for table %s\n",
383                                 info->hit_count, t->nstamps_max_mask + 1,
384                                 info->name);
385                         ret = -EINVAL;
386                         goto out;
387                 }
388 
389                 t->refcnt++;
390                 ret = 0;
391                 goto out;
392         }
393 
394         sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
395         if (sz <= PAGE_SIZE)
396                 t = kzalloc(sz, GFP_KERNEL);
397         else
398                 t = vzalloc(sz);
399         if (t == NULL) {
400                 ret = -ENOMEM;
401                 goto out;
402         }
403         t->refcnt = 1;
404         t->nstamps_max_mask = nstamp_mask;
405 
406         memcpy(&t->mask, &info->mask, sizeof(t->mask));
407         strcpy(t->name, info->name);
408         INIT_LIST_HEAD(&t->lru_list);
409         for (i = 0; i < ip_list_hash_size; i++)
410                 INIT_LIST_HEAD(&t->iphash[i]);
411 #ifdef CONFIG_PROC_FS
412         uid = make_kuid(&init_user_ns, ip_list_uid);
413         gid = make_kgid(&init_user_ns, ip_list_gid);
414         if (!uid_valid(uid) || !gid_valid(gid)) {
415                 recent_table_free(t);
416                 ret = -EINVAL;
417                 goto out;
418         }
419         pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
420                   &recent_mt_fops, t);
421         if (pde == NULL) {
422                 recent_table_free(t);
423                 ret = -ENOMEM;
424                 goto out;
425         }
426         proc_set_user(pde, uid, gid);
427 #endif
428         spin_lock_bh(&recent_lock);
429         list_add_tail(&t->list, &recent_net->tables);
430         spin_unlock_bh(&recent_lock);
431         ret = 0;
432 out:
433         mutex_unlock(&recent_mutex);
434         return ret;
435 }
436 
437 static int recent_mt_check_v0(const struct xt_mtchk_param *par)
438 {
439         const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
440         struct xt_recent_mtinfo_v1 info_v1;
441 
442         /* Copy revision 0 structure to revision 1 */
443         memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
444         /* Set default mask to ensure backward compatible behaviour */
445         memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
446 
447         return recent_mt_check(par, &info_v1);
448 }
449 
450 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
451 {
452         return recent_mt_check(par, par->matchinfo);
453 }
454 
455 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
456 {
457         struct recent_net *recent_net = recent_pernet(par->net);
458         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
459         struct recent_table *t;
460 
461         mutex_lock(&recent_mutex);
462         t = recent_table_lookup(recent_net, info->name);
463         if (--t->refcnt == 0) {
464                 spin_lock_bh(&recent_lock);
465                 list_del(&t->list);
466                 spin_unlock_bh(&recent_lock);
467 #ifdef CONFIG_PROC_FS
468                 if (recent_net->xt_recent != NULL)
469                         remove_proc_entry(t->name, recent_net->xt_recent);
470 #endif
471                 recent_table_flush(t);
472                 recent_table_free(t);
473         }
474         mutex_unlock(&recent_mutex);
475 }
476 
477 #ifdef CONFIG_PROC_FS
478 struct recent_iter_state {
479         const struct recent_table *table;
480         unsigned int            bucket;
481 };
482 
483 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
484         __acquires(recent_lock)
485 {
486         struct recent_iter_state *st = seq->private;
487         const struct recent_table *t = st->table;
488         struct recent_entry *e;
489         loff_t p = *pos;
490 
491         spin_lock_bh(&recent_lock);
492 
493         for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
494                 list_for_each_entry(e, &t->iphash[st->bucket], list)
495                         if (p-- == 0)
496                                 return e;
497         return NULL;
498 }
499 
500 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
501 {
502         struct recent_iter_state *st = seq->private;
503         const struct recent_table *t = st->table;
504         const struct recent_entry *e = v;
505         const struct list_head *head = e->list.next;
506 
507         while (head == &t->iphash[st->bucket]) {
508                 if (++st->bucket >= ip_list_hash_size)
509                         return NULL;
510                 head = t->iphash[st->bucket].next;
511         }
512         (*pos)++;
513         return list_entry(head, struct recent_entry, list);
514 }
515 
516 static void recent_seq_stop(struct seq_file *s, void *v)
517         __releases(recent_lock)
518 {
519         spin_unlock_bh(&recent_lock);
520 }
521 
522 static int recent_seq_show(struct seq_file *seq, void *v)
523 {
524         const struct recent_entry *e = v;
525         struct recent_iter_state *st = seq->private;
526         const struct recent_table *t = st->table;
527         unsigned int i;
528 
529         i = (e->index - 1) & t->nstamps_max_mask;
530 
531         if (e->family == NFPROTO_IPV4)
532                 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
533                            &e->addr.ip, e->ttl, e->stamps[i], e->index);
534         else
535                 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
536                            &e->addr.in6, e->ttl, e->stamps[i], e->index);
537         for (i = 0; i < e->nstamps; i++)
538                 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
539         seq_printf(seq, "\n");
540         return 0;
541 }
542 
543 static const struct seq_operations recent_seq_ops = {
544         .start          = recent_seq_start,
545         .next           = recent_seq_next,
546         .stop           = recent_seq_stop,
547         .show           = recent_seq_show,
548 };
549 
550 static int recent_seq_open(struct inode *inode, struct file *file)
551 {
552         struct recent_iter_state *st;
553 
554         st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
555         if (st == NULL)
556                 return -ENOMEM;
557 
558         st->table    = PDE_DATA(inode);
559         return 0;
560 }
561 
562 static ssize_t
563 recent_mt_proc_write(struct file *file, const char __user *input,
564                      size_t size, loff_t *loff)
565 {
566         struct recent_table *t = PDE_DATA(file_inode(file));
567         struct recent_entry *e;
568         char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
569         const char *c = buf;
570         union nf_inet_addr addr = {};
571         u_int16_t family;
572         bool add, succ;
573 
574         if (size == 0)
575                 return 0;
576         if (size > sizeof(buf))
577                 size = sizeof(buf);
578         if (copy_from_user(buf, input, size) != 0)
579                 return -EFAULT;
580 
581         /* Strict protocol! */
582         if (*loff != 0)
583                 return -ESPIPE;
584         switch (*c) {
585         case '/': /* flush table */
586                 spin_lock_bh(&recent_lock);
587                 recent_table_flush(t);
588                 spin_unlock_bh(&recent_lock);
589                 return size;
590         case '-': /* remove address */
591                 add = false;
592                 break;
593         case '+': /* add address */
594                 add = true;
595                 break;
596         default:
597                 pr_info("Need \"+ip\", \"-ip\" or \"/\"\n");
598                 return -EINVAL;
599         }
600 
601         ++c;
602         --size;
603         if (strnchr(c, size, ':') != NULL) {
604                 family = NFPROTO_IPV6;
605                 succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
606         } else {
607                 family = NFPROTO_IPV4;
608                 succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
609         }
610 
611         if (!succ) {
612                 pr_info("illegal address written to procfs\n");
613                 return -EINVAL;
614         }
615 
616         spin_lock_bh(&recent_lock);
617         e = recent_entry_lookup(t, &addr, family, 0);
618         if (e == NULL) {
619                 if (add)
620                         recent_entry_init(t, &addr, family, 0);
621         } else {
622                 if (add)
623                         recent_entry_update(t, e);
624                 else
625                         recent_entry_remove(t, e);
626         }
627         spin_unlock_bh(&recent_lock);
628         /* Note we removed one above */
629         *loff += size + 1;
630         return size + 1;
631 }
632 
633 static const struct file_operations recent_mt_fops = {
634         .open    = recent_seq_open,
635         .read    = seq_read,
636         .write   = recent_mt_proc_write,
637         .release = seq_release_private,
638         .owner   = THIS_MODULE,
639         .llseek = seq_lseek,
640 };
641 
642 static int __net_init recent_proc_net_init(struct net *net)
643 {
644         struct recent_net *recent_net = recent_pernet(net);
645 
646         recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
647         if (!recent_net->xt_recent)
648                 return -ENOMEM;
649         return 0;
650 }
651 
652 static void __net_exit recent_proc_net_exit(struct net *net)
653 {
654         struct recent_net *recent_net = recent_pernet(net);
655         struct recent_table *t;
656 
657         /* recent_net_exit() is called before recent_mt_destroy(). Make sure
658          * that the parent xt_recent proc entry is is empty before trying to
659          * remove it.
660          */
661         spin_lock_bh(&recent_lock);
662         list_for_each_entry(t, &recent_net->tables, list)
663                 remove_proc_entry(t->name, recent_net->xt_recent);
664 
665         recent_net->xt_recent = NULL;
666         spin_unlock_bh(&recent_lock);
667 
668         remove_proc_entry("xt_recent", net->proc_net);
669 }
670 #else
671 static inline int recent_proc_net_init(struct net *net)
672 {
673         return 0;
674 }
675 
676 static inline void recent_proc_net_exit(struct net *net)
677 {
678 }
679 #endif /* CONFIG_PROC_FS */
680 
681 static int __net_init recent_net_init(struct net *net)
682 {
683         struct recent_net *recent_net = recent_pernet(net);
684 
685         INIT_LIST_HEAD(&recent_net->tables);
686         return recent_proc_net_init(net);
687 }
688 
689 static void __net_exit recent_net_exit(struct net *net)
690 {
691         recent_proc_net_exit(net);
692 }
693 
694 static struct pernet_operations recent_net_ops = {
695         .init   = recent_net_init,
696         .exit   = recent_net_exit,
697         .id     = &recent_net_id,
698         .size   = sizeof(struct recent_net),
699 };
700 
701 static struct xt_match recent_mt_reg[] __read_mostly = {
702         {
703                 .name       = "recent",
704                 .revision   = 0,
705                 .family     = NFPROTO_IPV4,
706                 .match      = recent_mt,
707                 .matchsize  = sizeof(struct xt_recent_mtinfo),
708                 .checkentry = recent_mt_check_v0,
709                 .destroy    = recent_mt_destroy,
710                 .me         = THIS_MODULE,
711         },
712         {
713                 .name       = "recent",
714                 .revision   = 0,
715                 .family     = NFPROTO_IPV6,
716                 .match      = recent_mt,
717                 .matchsize  = sizeof(struct xt_recent_mtinfo),
718                 .checkentry = recent_mt_check_v0,
719                 .destroy    = recent_mt_destroy,
720                 .me         = THIS_MODULE,
721         },
722         {
723                 .name       = "recent",
724                 .revision   = 1,
725                 .family     = NFPROTO_IPV4,
726                 .match      = recent_mt,
727                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
728                 .checkentry = recent_mt_check_v1,
729                 .destroy    = recent_mt_destroy,
730                 .me         = THIS_MODULE,
731         },
732         {
733                 .name       = "recent",
734                 .revision   = 1,
735                 .family     = NFPROTO_IPV6,
736                 .match      = recent_mt,
737                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
738                 .checkentry = recent_mt_check_v1,
739                 .destroy    = recent_mt_destroy,
740                 .me         = THIS_MODULE,
741         }
742 };
743 
744 static int __init recent_mt_init(void)
745 {
746         int err;
747 
748         BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS);
749 
750         if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS)
751                 return -EINVAL;
752         ip_list_hash_size = 1 << fls(ip_list_tot);
753 
754         err = register_pernet_subsys(&recent_net_ops);
755         if (err)
756                 return err;
757         err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
758         if (err)
759                 unregister_pernet_subsys(&recent_net_ops);
760         return err;
761 }
762 
763 static void __exit recent_mt_exit(void)
764 {
765         xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
766         unregister_pernet_subsys(&recent_net_ops);
767 }
768 
769 module_init(recent_mt_init);
770 module_exit(recent_mt_exit);
771 

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