net/netfilter/xt_recent.c

   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
  36 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  37 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
  38 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
  39 MODULE_LICENSE("GPL");
  40 MODULE_ALIAS("ipt_recent");
  41 MODULE_ALIAS("ip6t_recent");
  42
  43 static unsigned int ip_list_tot __read_mostly = 100;
  44 static unsigned int ip_list_hash_size __read_mostly;
  45 static unsigned int ip_list_perms __read_mostly = 0644;
  46 static unsigned int ip_list_uid __read_mostly;
  47 static unsigned int ip_list_gid __read_mostly;
  48 module_param(ip_list_tot, uint, 0400);
  49 module_param(ip_list_hash_size, uint, 0400);
  50 module_param(ip_list_perms, uint, 0400);
  51 module_param(ip_list_uid, uint, 0644);
  52 module_param(ip_list_gid, uint, 0644);
  53 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
  54 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
  55 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
  56 MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
  57 MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
  58
  59 /* retained for backwards compatibility */
  60 static unsigned int ip_pkt_list_tot __read_mostly;
  61 module_param(ip_pkt_list_tot, uint, 0400);
  62 MODULE_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
  66 struct 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
  77 struct 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
  88 struct recent_net {
  89         struct list_head        tables;
  90 #ifdef CONFIG_PROC_FS
  91         struct proc_dir_entry   *xt_recent;
  92 #endif
  93 };
  94
  95 static unsigned int recent_net_id __read_mostly;
  96
  97 static inline struct recent_net *recent_pernet(struct net *net)
  98 {
  99         return net_generic(net, recent_net_id);
 100 }
 101
 102 static DEFINE_SPINLOCK(recent_lock);
 103 static DEFINE_MUTEX(recent_mutex);
 104
 105 #ifdef CONFIG_PROC_FS
 106 static const struct proc_ops recent_mt_proc_ops;
 107 #endif
 108
 109 static u_int32_t hash_rnd __read_mostly;
 110
 111 static 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
 117 static 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
 123 static struct recent_entry *
 124 recent_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
 144 static 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  */
 155 static void recent_entry_reap(struct recent_table *t, unsigned long time)
 156 {
 157         struct recent_entry *e;
 158
 159         /*
 160          * The head of the LRU list is always the oldest entry.
 161          */
 162         e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 163
 164         /*
 165          * The last time stamp is the most recent.
 166          */
 167         if (time_after(time, e->stamps[e->index-1]))
 168                 recent_entry_remove(t, e);
 169 }
 170
 171 static struct recent_entry *
 172 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
 173                   u_int16_t family, u_int8_t ttl)
 174 {
 175         struct recent_entry *e;
 176         unsigned int nstamps_max = t->nstamps_max_mask;
 177
 178         if (t->entries >= ip_list_tot) {
 179                 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 180                 recent_entry_remove(t, e);
 181         }
 182
 183         nstamps_max += 1;
 184         e = kmalloc(struct_size(e, stamps, nstamps_max), GFP_ATOMIC);
 185         if (e == NULL)
 186                 return NULL;
 187         memcpy(&e->addr, addr, sizeof(e->addr));
 188         e->ttl       = ttl;
 189         e->stamps[0] = jiffies;
 190         e->nstamps   = 1;
 191         e->index     = 1;
 192         e->family    = family;
 193         if (family == NFPROTO_IPV4)
 194                 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
 195         else
 196                 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
 197         list_add_tail(&e->lru_list, &t->lru_list);
 198         t->entries++;
 199         return e;
 200 }
 201
 202 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
 203 {
 204         e->index &= t->nstamps_max_mask;
 205         e->stamps[e->index++] = jiffies;
 206         if (e->index > e->nstamps)
 207                 e->nstamps = e->index;
 208         list_move_tail(&e->lru_list, &t->lru_list);
 209 }
 210
 211 static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
 212                                                 const char *name)
 213 {
 214         struct recent_table *t;
 215
 216         list_for_each_entry(t, &recent_net->tables, list)
 217                 if (!strcmp(t->name, name))
 218                         return t;
 219         return NULL;
 220 }
 221
 222 static void recent_table_flush(struct recent_table *t)
 223 {
 224         struct recent_entry *e, *next;
 225         unsigned int i;
 226
 227         for (i = 0; i < ip_list_hash_size; i++)
 228                 list_for_each_entry_safe(e, next, &t->iphash[i], list)
 229                         recent_entry_remove(t, e);
 230 }
 231
 232 static bool
 233 recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
 234 {
 235         struct net *net = xt_net(par);
 236         struct recent_net *recent_net = recent_pernet(net);
 237         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 238         struct recent_table *t;
 239         struct recent_entry *e;
 240         union nf_inet_addr addr = {}, addr_mask;
 241         u_int8_t ttl;
 242         bool ret = info->invert;
 243
 244         if (xt_family(par) == NFPROTO_IPV4) {
 245                 const struct iphdr *iph = ip_hdr(skb);
 246
 247                 if (info->side == XT_RECENT_DEST)
 248                         addr.ip = iph->daddr;
 249                 else
 250                         addr.ip = iph->saddr;
 251
 252                 ttl = iph->ttl;
 253         } else {
 254                 const struct ipv6hdr *iph = ipv6_hdr(skb);
 255
 256                 if (info->side == XT_RECENT_DEST)
 257                         memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
 258                 else
 259                         memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
 260
 261                 ttl = iph->hop_limit;
 262         }
 263
 264         /* use TTL as seen before forwarding */
 265         if (xt_out(par) != NULL &&
 266             (!skb->sk || !net_eq(net, sock_net(skb->sk))))
 267                 ttl++;
 268
 269         spin_lock_bh(&recent_lock);
 270         t = recent_table_lookup(recent_net, info->name);
 271
 272         nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
 273
 274         e = recent_entry_lookup(t, &addr_mask, xt_family(par),
 275                                 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
 276         if (e == NULL) {
 277                 if (!(info->check_set & XT_RECENT_SET))
 278                         goto out;
 279                 e = recent_entry_init(t, &addr_mask, xt_family(par), ttl);
 280                 if (e == NULL)
 281                         par->hotdrop = true;
 282                 ret = !ret;
 283                 goto out;
 284         }
 285
 286         if (info->check_set & XT_RECENT_SET)
 287                 ret = !ret;
 288         else if (info->check_set & XT_RECENT_REMOVE) {
 289                 recent_entry_remove(t, e);
 290                 ret = !ret;
 291         } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
 292                 unsigned long time = jiffies - info->seconds * HZ;
 293                 unsigned int i, hits = 0;
 294
 295                 for (i = 0; i < e->nstamps; i++) {
 296                         if (info->seconds && time_after(time, e->stamps[i]))
 297                                 continue;
 298                         if (!info->hit_count || ++hits >= info->hit_count) {
 299                                 ret = !ret;
 300                                 break;
 301                         }
 302                 }
 303
 304                 /* info->seconds must be non-zero */
 305                 if (info->check_set & XT_RECENT_REAP)
 306                         recent_entry_reap(t, time);
 307         }
 308
 309         if (info->check_set & XT_RECENT_SET ||
 310             (info->check_set & XT_RECENT_UPDATE && ret)) {
 311                 recent_entry_update(t, e);
 312                 e->ttl = ttl;
 313         }
 314 out:
 315         spin_unlock_bh(&recent_lock);
 316         return ret;
 317 }
 318
 319 static void recent_table_free(void *addr)
 320 {
 321         kvfree(addr);
 322 }
 323
 324 static int recent_mt_check(const struct xt_mtchk_param *par,
 325                            const struct xt_recent_mtinfo_v1 *info)
 326 {
 327         struct recent_net *recent_net = recent_pernet(par->net);
 328         struct recent_table *t;
 329 #ifdef CONFIG_PROC_FS
 330         struct proc_dir_entry *pde;
 331         kuid_t uid;
 332         kgid_t gid;
 333 #endif
 334         unsigned int nstamp_mask;
 335         unsigned int i;
 336         int ret = -EINVAL;
 337
 338         net_get_random_once(&hash_rnd, sizeof(hash_rnd));
 339
 340         if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
 341                 pr_info_ratelimited("Unsupported userspace flags (%08x)\n",
 342                                     info->check_set);
 343                 return -EINVAL;
 344         }
 345         if (hweight8(info->check_set &
 346                      (XT_RECENT_SET | XT_RECENT_REMOVE |
 347                       XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
 348                 return -EINVAL;
 349         if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
 350             (info->seconds || info->hit_count ||
 351             (info->check_set & XT_RECENT_MODIFIERS)))
 352                 return -EINVAL;
 353         if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
 354                 return -EINVAL;
 355         if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
 356                 pr_info_ratelimited("hitcount (%u) is larger than allowed maximum (%u)\n",
 357                                     info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
 358                 return -EINVAL;
 359         }
 360         ret = xt_check_proc_name(info->name, sizeof(info->name));
 361         if (ret)
 362                 return ret;
 363
 364         if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
 365                 nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
 366         else if (info->hit_count)
 367                 nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
 368         else
 369                 nstamp_mask = 32 - 1;
 370
 371         mutex_lock(&recent_mutex);
 372         t = recent_table_lookup(recent_net, info->name);
 373         if (t != NULL) {
 374                 if (nstamp_mask > t->nstamps_max_mask) {
 375                         spin_lock_bh(&recent_lock);
 376                         recent_table_flush(t);
 377                         t->nstamps_max_mask = nstamp_mask;
 378                         spin_unlock_bh(&recent_lock);
 379                 }
 380
 381                 t->refcnt++;
 382                 ret = 0;
 383                 goto out;
 384         }
 385
 386         t = kvzalloc(struct_size(t, iphash, ip_list_hash_size), GFP_KERNEL);
 387         if (t == NULL) {
 388                 ret = -ENOMEM;
 389                 goto out;
 390         }
 391         t->refcnt = 1;
 392         t->nstamps_max_mask = nstamp_mask;
 393
 394         memcpy(&t->mask, &info->mask, sizeof(t->mask));
 395         strcpy(t->name, info->name);
 396         INIT_LIST_HEAD(&t->lru_list);
 397         for (i = 0; i < ip_list_hash_size; i++)
 398                 INIT_LIST_HEAD(&t->iphash[i]);
 399 #ifdef CONFIG_PROC_FS
 400         uid = make_kuid(&init_user_ns, ip_list_uid);
 401         gid = make_kgid(&init_user_ns, ip_list_gid);
 402         if (!uid_valid(uid) || !gid_valid(gid)) {
 403                 recent_table_free(t);
 404                 ret = -EINVAL;
 405                 goto out;
 406         }
 407         pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
 408                                &recent_mt_proc_ops, t);
 409         if (pde == NULL) {
 410                 recent_table_free(t);
 411                 ret = -ENOMEM;
 412                 goto out;
 413         }
 414         proc_set_user(pde, uid, gid);
 415 #endif
 416         spin_lock_bh(&recent_lock);
 417         list_add_tail(&t->list, &recent_net->tables);
 418         spin_unlock_bh(&recent_lock);
 419         ret = 0;
 420 out:
 421         mutex_unlock(&recent_mutex);
 422         return ret;
 423 }
 424
 425 static int recent_mt_check_v0(const struct xt_mtchk_param *par)
 426 {
 427         const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
 428         struct xt_recent_mtinfo_v1 info_v1;
 429
 430         /* Copy revision 0 structure to revision 1 */
 431         memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
 432         /* Set default mask to ensure backward compatible behaviour */
 433         memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
 434
 435         return recent_mt_check(par, &info_v1);
 436 }
 437
 438 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
 439 {
 440         return recent_mt_check(par, par->matchinfo);
 441 }
 442
 443 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
 444 {
 445         struct recent_net *recent_net = recent_pernet(par->net);
 446         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 447         struct recent_table *t;
 448
 449         mutex_lock(&recent_mutex);
 450         t = recent_table_lookup(recent_net, info->name);
 451         if (--t->refcnt == 0) {
 452                 spin_lock_bh(&recent_lock);
 453                 list_del(&t->list);
 454                 spin_unlock_bh(&recent_lock);
 455 #ifdef CONFIG_PROC_FS
 456                 if (recent_net->xt_recent != NULL)
 457                         remove_proc_entry(t->name, recent_net->xt_recent);
 458 #endif
 459                 recent_table_flush(t);
 460                 recent_table_free(t);
 461         }
 462         mutex_unlock(&recent_mutex);
 463 }
 464
 465 #ifdef CONFIG_PROC_FS
 466 struct recent_iter_state {
 467         const struct recent_table *table;
 468         unsigned int            bucket;
 469 };
 470
 471 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
 472         __acquires(recent_lock)
 473 {
 474         struct recent_iter_state *st = seq->private;
 475         const struct recent_table *t = st->table;
 476         struct recent_entry *e;
 477         loff_t p = *pos;
 478
 479         spin_lock_bh(&recent_lock);
 480
 481         for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
 482                 list_for_each_entry(e, &t->iphash[st->bucket], list)
 483                         if (p-- == 0)
 484                                 return e;
 485         return NULL;
 486 }
 487
 488 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 489 {
 490         struct recent_iter_state *st = seq->private;
 491         const struct recent_table *t = st->table;
 492         const struct recent_entry *e = v;
 493         const struct list_head *head = e->list.next;
 494
 495         (*pos)++;
 496         while (head == &t->iphash[st->bucket]) {
 497                 if (++st->bucket >= ip_list_hash_size)
 498                         return NULL;
 499                 head = t->iphash[st->bucket].next;
 500         }
 501         return list_entry(head, struct recent_entry, list);
 502 }
 503
 504 static void recent_seq_stop(struct seq_file *s, void *v)
 505         __releases(recent_lock)
 506 {
 507         spin_unlock_bh(&recent_lock);
 508 }
 509
 510 static int recent_seq_show(struct seq_file *seq, void *v)
 511 {
 512         const struct recent_entry *e = v;
 513         struct recent_iter_state *st = seq->private;
 514         const struct recent_table *t = st->table;
 515         unsigned int i;
 516
 517         i = (e->index - 1) & t->nstamps_max_mask;
 518
 519         if (e->family == NFPROTO_IPV4)
 520                 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
 521                            &e->addr.ip, e->ttl, e->stamps[i], e->index);
 522         else
 523                 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
 524                            &e->addr.in6, e->ttl, e->stamps[i], e->index);
 525         for (i = 0; i < e->nstamps; i++)
 526                 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
 527         seq_putc(seq, '\n');
 528         return 0;
 529 }
 530
 531 static const struct seq_operations recent_seq_ops = {
 532         .start          = recent_seq_start,
 533         .next           = recent_seq_next,
 534         .stop           = recent_seq_stop,
 535         .show           = recent_seq_show,
 536 };
 537
 538 static int recent_seq_open(struct inode *inode, struct file *file)
 539 {
 540         struct recent_iter_state *st;
 541
 542         st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
 543         if (st == NULL)
 544                 return -ENOMEM;
 545
 546         st->table    = PDE_DATA(inode);
 547         return 0;
 548 }
 549
 550 static ssize_t
 551 recent_mt_proc_write(struct file *file, const char __user *input,
 552                      size_t size, loff_t *loff)
 553 {
 554         struct recent_table *t = PDE_DATA(file_inode(file));
 555         struct recent_entry *e;
 556         char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
 557         const char *c = buf;
 558         union nf_inet_addr addr = {};
 559         u_int16_t family;
 560         bool add, succ;
 561
 562         if (size == 0)
 563                 return 0;
 564         if (size > sizeof(buf))
 565                 size = sizeof(buf);
 566         if (copy_from_user(buf, input, size) != 0)
 567                 return -EFAULT;
 568
 569         /* Strict protocol! */
 570         if (*loff != 0)
 571                 return -ESPIPE;
 572         switch (*c) {
 573         case '/': /* flush table */
 574                 spin_lock_bh(&recent_lock);
 575                 recent_table_flush(t);
 576                 spin_unlock_bh(&recent_lock);
 577                 return size;
 578         case '-': /* remove address */
 579                 add = false;
 580                 break;
 581         case '+': /* add address */
 582                 add = true;
 583                 break;
 584         default:
 585                 pr_info_ratelimited("Need \"+ip\", \"-ip\" or \"/\"\n");
 586                 return -EINVAL;
 587         }
 588
 589         ++c;
 590         --size;
 591         if (strnchr(c, size, ':') != NULL) {
 592                 family = NFPROTO_IPV6;
 593                 succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
 594         } else {
 595                 family = NFPROTO_IPV4;
 596                 succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
 597         }
 598
 599         if (!succ)
 600                 return -EINVAL;
 601
 602         spin_lock_bh(&recent_lock);
 603         e = recent_entry_lookup(t, &addr, family, 0);
 604         if (e == NULL) {
 605                 if (add)
 606                         recent_entry_init(t, &addr, family, 0);
 607         } else {
 608                 if (add)
 609                         recent_entry_update(t, e);
 610                 else
 611                         recent_entry_remove(t, e);
 612         }
 613         spin_unlock_bh(&recent_lock);
 614         /* Note we removed one above */
 615         *loff += size + 1;
 616         return size + 1;
 617 }
 618
 619 static const struct proc_ops recent_mt_proc_ops = {
 620         .proc_open      = recent_seq_open,
 621         .proc_read      = seq_read,
 622         .proc_write     = recent_mt_proc_write,
 623         .proc_release   = seq_release_private,
 624         .proc_lseek     = seq_lseek,
 625 };
 626
 627 static int __net_init recent_proc_net_init(struct net *net)
 628 {
 629         struct recent_net *recent_net = recent_pernet(net);
 630
 631         recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
 632         if (!recent_net->xt_recent)
 633                 return -ENOMEM;
 634         return 0;
 635 }
 636
 637 static void __net_exit recent_proc_net_exit(struct net *net)
 638 {
 639         struct recent_net *recent_net = recent_pernet(net);
 640         struct recent_table *t;
 641
 642         /* recent_net_exit() is called before recent_mt_destroy(). Make sure
 643          * that the parent xt_recent proc entry is empty before trying to
 644          * remove it.
 645          */
 646         spin_lock_bh(&recent_lock);
 647         list_for_each_entry(t, &recent_net->tables, list)
 648                 remove_proc_entry(t->name, recent_net->xt_recent);
 649
 650         recent_net->xt_recent = NULL;
 651         spin_unlock_bh(&recent_lock);
 652
 653         remove_proc_entry("xt_recent", net->proc_net);
 654 }
 655 #else
 656 static inline int recent_proc_net_init(struct net *net)
 657 {
 658         return 0;
 659 }
 660
 661 static inline void recent_proc_net_exit(struct net *net)
 662 {
 663 }
 664 #endif /* CONFIG_PROC_FS */
 665
 666 static int __net_init recent_net_init(struct net *net)
 667 {
 668         struct recent_net *recent_net = recent_pernet(net);
 669
 670         INIT_LIST_HEAD(&recent_net->tables);
 671         return recent_proc_net_init(net);
 672 }
 673
 674 static void __net_exit recent_net_exit(struct net *net)
 675 {
 676         recent_proc_net_exit(net);
 677 }
 678
 679 static struct pernet_operations recent_net_ops = {
 680         .init   = recent_net_init,
 681         .exit   = recent_net_exit,
 682         .id     = &recent_net_id,
 683         .size   = sizeof(struct recent_net),
 684 };
 685
 686 static struct xt_match recent_mt_reg[] __read_mostly = {
 687         {
 688                 .name       = "recent",
 689                 .revision   = 0,
 690                 .family     = NFPROTO_IPV4,
 691                 .match      = recent_mt,
 692                 .matchsize  = sizeof(struct xt_recent_mtinfo),
 693                 .checkentry = recent_mt_check_v0,
 694                 .destroy    = recent_mt_destroy,
 695                 .me         = THIS_MODULE,
 696         },
 697         {
 698                 .name       = "recent",
 699                 .revision   = 0,
 700                 .family     = NFPROTO_IPV6,
 701                 .match      = recent_mt,
 702                 .matchsize  = sizeof(struct xt_recent_mtinfo),
 703                 .checkentry = recent_mt_check_v0,
 704                 .destroy    = recent_mt_destroy,
 705                 .me         = THIS_MODULE,
 706         },
 707         {
 708                 .name       = "recent",
 709                 .revision   = 1,
 710                 .family     = NFPROTO_IPV4,
 711                 .match      = recent_mt,
 712                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
 713                 .checkentry = recent_mt_check_v1,
 714                 .destroy    = recent_mt_destroy,
 715                 .me         = THIS_MODULE,
 716         },
 717         {
 718                 .name       = "recent",
 719                 .revision   = 1,
 720                 .family     = NFPROTO_IPV6,
 721                 .match      = recent_mt,
 722                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
 723                 .checkentry = recent_mt_check_v1,
 724                 .destroy    = recent_mt_destroy,
 725                 .me         = THIS_MODULE,
 726         }
 727 };
 728
 729 static int __init recent_mt_init(void)
 730 {
 731         int err;
 732
 733         BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS);
 734
 735         if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS)
 736                 return -EINVAL;
 737         ip_list_hash_size = 1 << fls(ip_list_tot);
 738
 739         err = register_pernet_subsys(&recent_net_ops);
 740         if (err)
 741                 return err;
 742         err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 743         if (err)
 744                 unregister_pernet_subsys(&recent_net_ops);
 745         return err;
 746 }
 747
 748 static void __exit recent_mt_exit(void)
 749 {
 750         xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 751         unregister_pernet_subsys(&recent_net_ops);
 752 }
 753
 754 module_init(recent_mt_init);
 755 module_exit(recent_mt_exit);