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 unsigned 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
 114 static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
 115 {
 116         return jhash_1word((__force u32)addr->ip, hash_rnd) &
 117                (ip_list_hash_size - 1);
 118 }
 119
 120 static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
 121 {
 122         return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
 123                (ip_list_hash_size - 1);
 124 }
 125
 126 static struct recent_entry *
 127 recent_entry_lookup(const struct recent_table *table,
 128                     const union nf_inet_addr *addrp, u_int16_t family,
 129                     u_int8_t ttl)
 130 {
 131         struct recent_entry *e;
 132         unsigned int h;
 133
 134         if (family == NFPROTO_IPV4)
 135                 h = recent_entry_hash4(addrp);
 136         else
 137                 h = recent_entry_hash6(addrp);
 138
 139         list_for_each_entry(e, &table->iphash[h], list)
 140                 if (e->family == family &&
 141                     memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
 142                     (ttl == e->ttl || ttl == 0 || e->ttl == 0))
 143                         return e;
 144         return NULL;
 145 }
 146
 147 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
 148 {
 149         list_del(&e->list);
 150         list_del(&e->lru_list);
 151         kfree(e);
 152         t->entries--;
 153 }
 154
 155 /*
 156  * Drop entries with timestamps older then 'time'.
 157  */
 158 static void recent_entry_reap(struct recent_table *t, unsigned long time)
 159 {
 160         struct recent_entry *e;
 161
 162         /*
 163          * The head of the LRU list is always the oldest entry.
 164          */
 165         e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 166
 167         /*
 168          * The last time stamp is the most recent.
 169          */
 170         if (time_after(time, e->stamps[e->index-1]))
 171                 recent_entry_remove(t, e);
 172 }
 173
 174 static struct recent_entry *
 175 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
 176                   u_int16_t family, u_int8_t ttl)
 177 {
 178         struct recent_entry *e;
 179         unsigned int nstamps_max = t->nstamps_max_mask;
 180
 181         if (t->entries >= ip_list_tot) {
 182                 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 183                 recent_entry_remove(t, e);
 184         }
 185
 186         nstamps_max += 1;
 187         e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * nstamps_max,
 188                     GFP_ATOMIC);
 189         if (e == NULL)
 190                 return NULL;
 191         memcpy(&e->addr, addr, sizeof(e->addr));
 192         e->ttl       = ttl;
 193         e->stamps[0] = jiffies;
 194         e->nstamps   = 1;
 195         e->index     = 1;
 196         e->family    = family;
 197         if (family == NFPROTO_IPV4)
 198                 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
 199         else
 200                 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
 201         list_add_tail(&e->lru_list, &t->lru_list);
 202         t->entries++;
 203         return e;
 204 }
 205
 206 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
 207 {
 208         e->index &= t->nstamps_max_mask;
 209         e->stamps[e->index++] = jiffies;
 210         if (e->index > e->nstamps)
 211                 e->nstamps = e->index;
 212         list_move_tail(&e->lru_list, &t->lru_list);
 213 }
 214
 215 static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
 216                                                 const char *name)
 217 {
 218         struct recent_table *t;
 219
 220         list_for_each_entry(t, &recent_net->tables, list)
 221                 if (!strcmp(t->name, name))
 222                         return t;
 223         return NULL;
 224 }
 225
 226 static void recent_table_flush(struct recent_table *t)
 227 {
 228         struct recent_entry *e, *next;
 229         unsigned int i;
 230
 231         for (i = 0; i < ip_list_hash_size; i++)
 232                 list_for_each_entry_safe(e, next, &t->iphash[i], list)
 233                         recent_entry_remove(t, e);
 234 }
 235
 236 static bool
 237 recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
 238 {
 239         struct net *net = xt_net(par);
 240         struct recent_net *recent_net = recent_pernet(net);
 241         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 242         struct recent_table *t;
 243         struct recent_entry *e;
 244         union nf_inet_addr addr = {}, addr_mask;
 245         u_int8_t ttl;
 246         bool ret = info->invert;
 247
 248         if (xt_family(par) == NFPROTO_IPV4) {
 249                 const struct iphdr *iph = ip_hdr(skb);
 250
 251                 if (info->side == XT_RECENT_DEST)
 252                         addr.ip = iph->daddr;
 253                 else
 254                         addr.ip = iph->saddr;
 255
 256                 ttl = iph->ttl;
 257         } else {
 258                 const struct ipv6hdr *iph = ipv6_hdr(skb);
 259
 260                 if (info->side == XT_RECENT_DEST)
 261                         memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
 262                 else
 263                         memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
 264
 265                 ttl = iph->hop_limit;
 266         }
 267
 268         /* use TTL as seen before forwarding */
 269         if (xt_out(par) != NULL && skb->sk == NULL)
 270                 ttl++;
 271
 272         spin_lock_bh(&recent_lock);
 273         t = recent_table_lookup(recent_net, info->name);
 274
 275         nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
 276
 277         e = recent_entry_lookup(t, &addr_mask, xt_family(par),
 278                                 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
 279         if (e == NULL) {
 280                 if (!(info->check_set & XT_RECENT_SET))
 281                         goto out;
 282                 e = recent_entry_init(t, &addr_mask, xt_family(par), ttl);
 283                 if (e == NULL)
 284                         par->hotdrop = true;
 285                 ret = !ret;
 286                 goto out;
 287         }
 288
 289         if (info->check_set & XT_RECENT_SET)
 290                 ret = !ret;
 291         else if (info->check_set & XT_RECENT_REMOVE) {
 292                 recent_entry_remove(t, e);
 293                 ret = !ret;
 294         } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
 295                 unsigned long time = jiffies - info->seconds * HZ;
 296                 unsigned int i, hits = 0;
 297
 298                 for (i = 0; i < e->nstamps; i++) {
 299                         if (info->seconds && time_after(time, e->stamps[i]))
 300                                 continue;
 301                         if (!info->hit_count || ++hits >= info->hit_count) {
 302                                 ret = !ret;
 303                                 break;
 304                         }
 305                 }
 306
 307                 /* info->seconds must be non-zero */
 308                 if (info->check_set & XT_RECENT_REAP)
 309                         recent_entry_reap(t, time);
 310         }
 311
 312         if (info->check_set & XT_RECENT_SET ||
 313             (info->check_set & XT_RECENT_UPDATE && ret)) {
 314                 recent_entry_update(t, e);
 315                 e->ttl = ttl;
 316         }
 317 out:
 318         spin_unlock_bh(&recent_lock);
 319         return ret;
 320 }
 321
 322 static void recent_table_free(void *addr)
 323 {
 324         kvfree(addr);
 325 }
 326
 327 static int recent_mt_check(const struct xt_mtchk_param *par,
 328                            const struct xt_recent_mtinfo_v1 *info)
 329 {
 330         struct recent_net *recent_net = recent_pernet(par->net);
 331         struct recent_table *t;
 332 #ifdef CONFIG_PROC_FS
 333         struct proc_dir_entry *pde;
 334         kuid_t uid;
 335         kgid_t gid;
 336 #endif
 337         unsigned int nstamp_mask;
 338         unsigned int i;
 339         int ret = -EINVAL;
 340         size_t sz;
 341
 342         net_get_random_once(&hash_rnd, sizeof(hash_rnd));
 343
 344         if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
 345                 pr_info("Unsupported user space flags (%08x)\n",
 346                         info->check_set);
 347                 return -EINVAL;
 348         }
 349         if (hweight8(info->check_set &
 350                      (XT_RECENT_SET | XT_RECENT_REMOVE |
 351                       XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
 352                 return -EINVAL;
 353         if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
 354             (info->seconds || info->hit_count ||
 355             (info->check_set & XT_RECENT_MODIFIERS)))
 356                 return -EINVAL;
 357         if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
 358                 return -EINVAL;
 359         if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
 360                 pr_info("hitcount (%u) is larger than allowed maximum (%u)\n",
 361                         info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
 362                 return -EINVAL;
 363         }
 364         if (info->name[0] == '\0' ||
 365             strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
 366                 return -EINVAL;
 367
 368         if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
 369                 nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
 370         else if (info->hit_count)
 371                 nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
 372         else
 373                 nstamp_mask = 32 - 1;
 374
 375         mutex_lock(&recent_mutex);
 376         t = recent_table_lookup(recent_net, info->name);
 377         if (t != NULL) {
 378                 if (nstamp_mask > t->nstamps_max_mask) {
 379                         spin_lock_bh(&recent_lock);
 380                         recent_table_flush(t);
 381                         t->nstamps_max_mask = nstamp_mask;
 382                         spin_unlock_bh(&recent_lock);
 383                 }
 384
 385                 t->refcnt++;
 386                 ret = 0;
 387                 goto out;
 388         }
 389
 390         sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
 391         if (sz <= PAGE_SIZE)
 392                 t = kzalloc(sz, GFP_KERNEL);
 393         else
 394                 t = vzalloc(sz);
 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_fops, 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;
 428 out:
 429         mutex_unlock(&recent_mutex);
 430         return ret;
 431 }
 432
 433 static 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
 446 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
 447 {
 448         return recent_mt_check(par, par->matchinfo);
 449 }
 450
 451 static 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
 474 struct recent_iter_state {
 475         const struct recent_table *table;
 476         unsigned int            bucket;
 477 };
 478
 479 static 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
 496 static 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         while (head == &t->iphash[st->bucket]) {
 504                 if (++st->bucket >= ip_list_hash_size)
 505                         return NULL;
 506                 head = t->iphash[st->bucket].next;
 507         }
 508         (*pos)++;
 509         return list_entry(head, struct recent_entry, list);
 510 }
 511
 512 static void recent_seq_stop(struct seq_file *s, void *v)
 513         __releases(recent_lock)
 514 {
 515         spin_unlock_bh(&recent_lock);
 516 }
 517
 518 static 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_printf(seq, "\n");
 536         return 0;
 537 }
 538
 539 static 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
 546 static 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
 558 static ssize_t
 559 recent_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("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                 pr_info("illegal address written to procfs\n");
 609                 return -EINVAL;
 610         }
 611
 612         spin_lock_bh(&recent_lock);
 613         e = recent_entry_lookup(t, &addr, family, 0);
 614         if (e == NULL) {
 615                 if (add)
 616                         recent_entry_init(t, &addr, family, 0);
 617         } else {
 618                 if (add)
 619                         recent_entry_update(t, e);
 620                 else
 621                         recent_entry_remove(t, e);
 622         }
 623         spin_unlock_bh(&recent_lock);
 624         /* Note we removed one above */
 625         *loff += size + 1;
 626         return size + 1;
 627 }
 628
 629 static const struct file_operations recent_mt_fops = {
 630         .open    = recent_seq_open,
 631         .read    = seq_read,
 632         .write   = recent_mt_proc_write,
 633         .release = seq_release_private,
 634         .owner   = THIS_MODULE,
 635         .llseek = seq_lseek,
 636 };
 637
 638 static int __net_init recent_proc_net_init(struct net *net)
 639 {
 640         struct recent_net *recent_net = recent_pernet(net);
 641
 642         recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
 643         if (!recent_net->xt_recent)
 644                 return -ENOMEM;
 645         return 0;
 646 }
 647
 648 static void __net_exit recent_proc_net_exit(struct net *net)
 649 {
 650         struct recent_net *recent_net = recent_pernet(net);
 651         struct recent_table *t;
 652
 653         /* recent_net_exit() is called before recent_mt_destroy(). Make sure
 654          * that the parent xt_recent proc entry is is empty before trying to
 655          * remove it.
 656          */
 657         spin_lock_bh(&recent_lock);
 658         list_for_each_entry(t, &recent_net->tables, list)
 659                 remove_proc_entry(t->name, recent_net->xt_recent);
 660
 661         recent_net->xt_recent = NULL;
 662         spin_unlock_bh(&recent_lock);
 663
 664         remove_proc_entry("xt_recent", net->proc_net);
 665 }
 666 #else
 667 static inline int recent_proc_net_init(struct net *net)
 668 {
 669         return 0;
 670 }
 671
 672 static inline void recent_proc_net_exit(struct net *net)
 673 {
 674 }
 675 #endif /* CONFIG_PROC_FS */
 676
 677 static int __net_init recent_net_init(struct net *net)
 678 {
 679         struct recent_net *recent_net = recent_pernet(net);
 680
 681         INIT_LIST_HEAD(&recent_net->tables);
 682         return recent_proc_net_init(net);
 683 }
 684
 685 static void __net_exit recent_net_exit(struct net *net)
 686 {
 687         recent_proc_net_exit(net);
 688 }
 689
 690 static struct pernet_operations recent_net_ops = {
 691         .init   = recent_net_init,
 692         .exit   = recent_net_exit,
 693         .id     = &recent_net_id,
 694         .size   = sizeof(struct recent_net),
 695 };
 696
 697 static struct xt_match recent_mt_reg[] __read_mostly = {
 698         {
 699                 .name       = "recent",
 700                 .revision   = 0,
 701                 .family     = NFPROTO_IPV4,
 702                 .match      = recent_mt,
 703                 .matchsize  = sizeof(struct xt_recent_mtinfo),
 704                 .checkentry = recent_mt_check_v0,
 705                 .destroy    = recent_mt_destroy,
 706                 .me         = THIS_MODULE,
 707         },
 708         {
 709                 .name       = "recent",
 710                 .revision   = 0,
 711                 .family     = NFPROTO_IPV6,
 712                 .match      = recent_mt,
 713                 .matchsize  = sizeof(struct xt_recent_mtinfo),
 714                 .checkentry = recent_mt_check_v0,
 715                 .destroy    = recent_mt_destroy,
 716                 .me         = THIS_MODULE,
 717         },
 718         {
 719                 .name       = "recent",
 720                 .revision   = 1,
 721                 .family     = NFPROTO_IPV4,
 722                 .match      = recent_mt,
 723                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
 724                 .checkentry = recent_mt_check_v1,
 725                 .destroy    = recent_mt_destroy,
 726                 .me         = THIS_MODULE,
 727         },
 728         {
 729                 .name       = "recent",
 730                 .revision   = 1,
 731                 .family     = NFPROTO_IPV6,
 732                 .match      = recent_mt,
 733                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
 734                 .checkentry = recent_mt_check_v1,
 735                 .destroy    = recent_mt_destroy,
 736                 .me         = THIS_MODULE,
 737         }
 738 };
 739
 740 static int __init recent_mt_init(void)
 741 {
 742         int err;
 743
 744         BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS);
 745
 746         if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS)
 747                 return -EINVAL;
 748         ip_list_hash_size = 1 << fls(ip_list_tot);
 749
 750         err = register_pernet_subsys(&recent_net_ops);
 751         if (err)
 752                 return err;
 753         err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 754         if (err)
 755                 unregister_pernet_subsys(&recent_net_ops);
 756         return err;
 757 }
 758
 759 static void __exit recent_mt_exit(void)
 760 {
 761         xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 762         unregister_pernet_subsys(&recent_net_ops);
 763 }
 764
 765 module_init(recent_mt_init);
 766 module_exit(recent_mt_exit);