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);