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_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         t = kvzalloc(sz, GFP_KERNEL);
 392         if (t == NULL) {
 393                 ret = -ENOMEM;
 394                 goto out;
 395         }
 396         t->refcnt = 1;
 397         t->nstamps_max_mask = nstamp_mask;
 398
 399         memcpy(&t->mask, &info->mask, sizeof(t->mask));
 400         strcpy(t->name, info->name);
 401         INIT_LIST_HEAD(&t->lru_list);
 402         for (i = 0; i < ip_list_hash_size; i++)
 403                 INIT_LIST_HEAD(&t->iphash[i]);
 404 #ifdef CONFIG_PROC_FS
 405         uid = make_kuid(&init_user_ns, ip_list_uid);
 406         gid = make_kgid(&init_user_ns, ip_list_gid);
 407         if (!uid_valid(uid) || !gid_valid(gid)) {
 408                 recent_table_free(t);
 409                 ret = -EINVAL;
 410                 goto out;
 411         }
 412         pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
 413                   &recent_mt_fops, t);
 414         if (pde == NULL) {
 415                 recent_table_free(t);
 416                 ret = -ENOMEM;
 417                 goto out;
 418         }
 419         proc_set_user(pde, uid, gid);
 420 #endif
 421         spin_lock_bh(&recent_lock);
 422         list_add_tail(&t->list, &recent_net->tables);
 423         spin_unlock_bh(&recent_lock);
 424         ret = 0;
 425 out:
 426         mutex_unlock(&recent_mutex);
 427         return ret;
 428 }
 429
 430 static int recent_mt_check_v0(const struct xt_mtchk_param *par)
 431 {
 432         const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
 433         struct xt_recent_mtinfo_v1 info_v1;
 434
 435         /* Copy revision 0 structure to revision 1 */
 436         memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
 437         /* Set default mask to ensure backward compatible behaviour */
 438         memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
 439
 440         return recent_mt_check(par, &info_v1);
 441 }
 442
 443 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
 444 {
 445         return recent_mt_check(par, par->matchinfo);
 446 }
 447
 448 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
 449 {
 450         struct recent_net *recent_net = recent_pernet(par->net);
 451         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 452         struct recent_table *t;
 453
 454         mutex_lock(&recent_mutex);
 455         t = recent_table_lookup(recent_net, info->name);
 456         if (--t->refcnt == 0) {
 457                 spin_lock_bh(&recent_lock);
 458                 list_del(&t->list);
 459                 spin_unlock_bh(&recent_lock);
 460 #ifdef CONFIG_PROC_FS
 461                 if (recent_net->xt_recent != NULL)
 462                         remove_proc_entry(t->name, recent_net->xt_recent);
 463 #endif
 464                 recent_table_flush(t);
 465                 recent_table_free(t);
 466         }
 467         mutex_unlock(&recent_mutex);
 468 }
 469
 470 #ifdef CONFIG_PROC_FS
 471 struct recent_iter_state {
 472         const struct recent_table *table;
 473         unsigned int            bucket;
 474 };
 475
 476 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
 477         __acquires(recent_lock)
 478 {
 479         struct recent_iter_state *st = seq->private;
 480         const struct recent_table *t = st->table;
 481         struct recent_entry *e;
 482         loff_t p = *pos;
 483
 484         spin_lock_bh(&recent_lock);
 485
 486         for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
 487                 list_for_each_entry(e, &t->iphash[st->bucket], list)
 488                         if (p-- == 0)
 489                                 return e;
 490         return NULL;
 491 }
 492
 493 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 494 {
 495         struct recent_iter_state *st = seq->private;
 496         const struct recent_table *t = st->table;
 497         const struct recent_entry *e = v;
 498         const struct list_head *head = e->list.next;
 499
 500         while (head == &t->iphash[st->bucket]) {
 501                 if (++st->bucket >= ip_list_hash_size)
 502                         return NULL;
 503                 head = t->iphash[st->bucket].next;
 504         }
 505         (*pos)++;
 506         return list_entry(head, struct recent_entry, list);
 507 }
 508
 509 static void recent_seq_stop(struct seq_file *s, void *v)
 510         __releases(recent_lock)
 511 {
 512         spin_unlock_bh(&recent_lock);
 513 }
 514
 515 static int recent_seq_show(struct seq_file *seq, void *v)
 516 {
 517         const struct recent_entry *e = v;
 518         struct recent_iter_state *st = seq->private;
 519         const struct recent_table *t = st->table;
 520         unsigned int i;
 521
 522         i = (e->index - 1) & t->nstamps_max_mask;
 523
 524         if (e->family == NFPROTO_IPV4)
 525                 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
 526                            &e->addr.ip, e->ttl, e->stamps[i], e->index);
 527         else
 528                 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
 529                            &e->addr.in6, e->ttl, e->stamps[i], e->index);
 530         for (i = 0; i < e->nstamps; i++)
 531                 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
 532         seq_putc(seq, '\n');
 533         return 0;
 534 }
 535
 536 static const struct seq_operations recent_seq_ops = {
 537         .start          = recent_seq_start,
 538         .next           = recent_seq_next,
 539         .stop           = recent_seq_stop,
 540         .show           = recent_seq_show,
 541 };
 542
 543 static int recent_seq_open(struct inode *inode, struct file *file)
 544 {
 545         struct recent_iter_state *st;
 546
 547         st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
 548         if (st == NULL)
 549                 return -ENOMEM;
 550
 551         st->table    = PDE_DATA(inode);
 552         return 0;
 553 }
 554
 555 static ssize_t
 556 recent_mt_proc_write(struct file *file, const char __user *input,
 557                      size_t size, loff_t *loff)
 558 {
 559         struct recent_table *t = PDE_DATA(file_inode(file));
 560         struct recent_entry *e;
 561         char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
 562         const char *c = buf;
 563         union nf_inet_addr addr = {};
 564         u_int16_t family;
 565         bool add, succ;
 566
 567         if (size == 0)
 568                 return 0;
 569         if (size > sizeof(buf))
 570                 size = sizeof(buf);
 571         if (copy_from_user(buf, input, size) != 0)
 572                 return -EFAULT;
 573
 574         /* Strict protocol! */
 575         if (*loff != 0)
 576                 return -ESPIPE;
 577         switch (*c) {
 578         case '/': /* flush table */
 579                 spin_lock_bh(&recent_lock);
 580                 recent_table_flush(t);
 581                 spin_unlock_bh(&recent_lock);
 582                 return size;
 583         case '-': /* remove address */
 584                 add = false;
 585                 break;
 586         case '+': /* add address */
 587                 add = true;
 588                 break;
 589         default:
 590                 pr_info("Need \"+ip\", \"-ip\" or \"/\"\n");
 591                 return -EINVAL;
 592         }
 593
 594         ++c;
 595         --size;
 596         if (strnchr(c, size, ':') != NULL) {
 597                 family = NFPROTO_IPV6;
 598                 succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
 599         } else {
 600                 family = NFPROTO_IPV4;
 601                 succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
 602         }
 603
 604         if (!succ) {
 605                 pr_info("illegal address written to procfs\n");
 606                 return -EINVAL;
 607         }
 608
 609         spin_lock_bh(&recent_lock);
 610         e = recent_entry_lookup(t, &addr, family, 0);
 611         if (e == NULL) {
 612                 if (add)
 613                         recent_entry_init(t, &addr, family, 0);
 614         } else {
 615                 if (add)
 616                         recent_entry_update(t, e);
 617                 else
 618                         recent_entry_remove(t, e);
 619         }
 620         spin_unlock_bh(&recent_lock);
 621         /* Note we removed one above */
 622         *loff += size + 1;
 623         return size + 1;
 624 }
 625
 626 static const struct file_operations recent_mt_fops = {
 627         .open    = recent_seq_open,
 628         .read    = seq_read,
 629         .write   = recent_mt_proc_write,
 630         .release = seq_release_private,
 631         .owner   = THIS_MODULE,
 632         .llseek = seq_lseek,
 633 };
 634
 635 static 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
 645 static 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 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
 664 static inline int recent_proc_net_init(struct net *net)
 665 {
 666         return 0;
 667 }
 668
 669 static inline void recent_proc_net_exit(struct net *net)
 670 {
 671 }
 672 #endif /* CONFIG_PROC_FS */
 673
 674 static 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
 682 static void __net_exit recent_net_exit(struct net *net)
 683 {
 684         recent_proc_net_exit(net);
 685 }
 686
 687 static 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
 694 static 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
 737 static 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
 756 static 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
 762 module_init(recent_mt_init);
 763 module_exit(recent_mt_exit);