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 = par->net;
 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 (nstamp_mask > t->nstamps_max_mask) {
 382                         spin_lock_bh(&recent_lock);
 383                         recent_table_flush(t);
 384                         t->nstamps_max_mask = nstamp_mask;
 385                         spin_unlock_bh(&recent_lock);
 386                 }
 387
 388                 t->refcnt++;
 389                 ret = 0;
 390                 goto out;
 391         }
 392
 393         sz = sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size;
 394         if (sz <= PAGE_SIZE)
 395                 t = kzalloc(sz, GFP_KERNEL);
 396         else
 397                 t = vzalloc(sz);
 398         if (t == NULL) {
 399                 ret = -ENOMEM;
 400                 goto out;
 401         }
 402         t->refcnt = 1;
 403         t->nstamps_max_mask = nstamp_mask;
 404
 405         memcpy(&t->mask, &info->mask, sizeof(t->mask));
 406         strcpy(t->name, info->name);
 407         INIT_LIST_HEAD(&t->lru_list);
 408         for (i = 0; i < ip_list_hash_size; i++)
 409                 INIT_LIST_HEAD(&t->iphash[i]);
 410 #ifdef CONFIG_PROC_FS
 411         uid = make_kuid(&init_user_ns, ip_list_uid);
 412         gid = make_kgid(&init_user_ns, ip_list_gid);
 413         if (!uid_valid(uid) || !gid_valid(gid)) {
 414                 recent_table_free(t);
 415                 ret = -EINVAL;
 416                 goto out;
 417         }
 418         pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
 419                   &recent_mt_fops, t);
 420         if (pde == NULL) {
 421                 recent_table_free(t);
 422                 ret = -ENOMEM;
 423                 goto out;
 424         }
 425         proc_set_user(pde, uid, gid);
 426 #endif
 427         spin_lock_bh(&recent_lock);
 428         list_add_tail(&t->list, &recent_net->tables);
 429         spin_unlock_bh(&recent_lock);
 430         ret = 0;
 431 out:
 432         mutex_unlock(&recent_mutex);
 433         return ret;
 434 }
 435
 436 static int recent_mt_check_v0(const struct xt_mtchk_param *par)
 437 {
 438         const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
 439         struct xt_recent_mtinfo_v1 info_v1;
 440
 441         /* Copy revision 0 structure to revision 1 */
 442         memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
 443         /* Set default mask to ensure backward compatible behaviour */
 444         memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
 445
 446         return recent_mt_check(par, &info_v1);
 447 }
 448
 449 static int recent_mt_check_v1(const struct xt_mtchk_param *par)
 450 {
 451         return recent_mt_check(par, par->matchinfo);
 452 }
 453
 454 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
 455 {
 456         struct recent_net *recent_net = recent_pernet(par->net);
 457         const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 458         struct recent_table *t;
 459
 460         mutex_lock(&recent_mutex);
 461         t = recent_table_lookup(recent_net, info->name);
 462         if (--t->refcnt == 0) {
 463                 spin_lock_bh(&recent_lock);
 464                 list_del(&t->list);
 465                 spin_unlock_bh(&recent_lock);
 466 #ifdef CONFIG_PROC_FS
 467                 if (recent_net->xt_recent != NULL)
 468                         remove_proc_entry(t->name, recent_net->xt_recent);
 469 #endif
 470                 recent_table_flush(t);
 471                 recent_table_free(t);
 472         }
 473         mutex_unlock(&recent_mutex);
 474 }
 475
 476 #ifdef CONFIG_PROC_FS
 477 struct recent_iter_state {
 478         const struct recent_table *table;
 479         unsigned int            bucket;
 480 };
 481
 482 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
 483         __acquires(recent_lock)
 484 {
 485         struct recent_iter_state *st = seq->private;
 486         const struct recent_table *t = st->table;
 487         struct recent_entry *e;
 488         loff_t p = *pos;
 489
 490         spin_lock_bh(&recent_lock);
 491
 492         for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
 493                 list_for_each_entry(e, &t->iphash[st->bucket], list)
 494                         if (p-- == 0)
 495                                 return e;
 496         return NULL;
 497 }
 498
 499 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 500 {
 501         struct recent_iter_state *st = seq->private;
 502         const struct recent_table *t = st->table;
 503         const struct recent_entry *e = v;
 504         const struct list_head *head = e->list.next;
 505
 506         while (head == &t->iphash[st->bucket]) {
 507                 if (++st->bucket >= ip_list_hash_size)
 508                         return NULL;
 509                 head = t->iphash[st->bucket].next;
 510         }
 511         (*pos)++;
 512         return list_entry(head, struct recent_entry, list);
 513 }
 514
 515 static void recent_seq_stop(struct seq_file *s, void *v)
 516         __releases(recent_lock)
 517 {
 518         spin_unlock_bh(&recent_lock);
 519 }
 520
 521 static int recent_seq_show(struct seq_file *seq, void *v)
 522 {
 523         const struct recent_entry *e = v;
 524         struct recent_iter_state *st = seq->private;
 525         const struct recent_table *t = st->table;
 526         unsigned int i;
 527
 528         i = (e->index - 1) & t->nstamps_max_mask;
 529
 530         if (e->family == NFPROTO_IPV4)
 531                 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
 532                            &e->addr.ip, e->ttl, e->stamps[i], e->index);
 533         else
 534                 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
 535                            &e->addr.in6, e->ttl, e->stamps[i], e->index);
 536         for (i = 0; i < e->nstamps; i++)
 537                 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
 538         seq_printf(seq, "\n");
 539         return 0;
 540 }
 541
 542 static const struct seq_operations recent_seq_ops = {
 543         .start          = recent_seq_start,
 544         .next           = recent_seq_next,
 545         .stop           = recent_seq_stop,
 546         .show           = recent_seq_show,
 547 };
 548
 549 static int recent_seq_open(struct inode *inode, struct file *file)
 550 {
 551         struct recent_iter_state *st;
 552
 553         st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
 554         if (st == NULL)
 555                 return -ENOMEM;
 556
 557         st->table    = PDE_DATA(inode);
 558         return 0;
 559 }
 560
 561 static ssize_t
 562 recent_mt_proc_write(struct file *file, const char __user *input,
 563                      size_t size, loff_t *loff)
 564 {
 565         struct recent_table *t = PDE_DATA(file_inode(file));
 566         struct recent_entry *e;
 567         char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
 568         const char *c = buf;
 569         union nf_inet_addr addr = {};
 570         u_int16_t family;
 571         bool add, succ;
 572
 573         if (size == 0)
 574                 return 0;
 575         if (size > sizeof(buf))
 576                 size = sizeof(buf);
 577         if (copy_from_user(buf, input, size) != 0)
 578                 return -EFAULT;
 579
 580         /* Strict protocol! */
 581         if (*loff != 0)
 582                 return -ESPIPE;
 583         switch (*c) {
 584         case '/': /* flush table */
 585                 spin_lock_bh(&recent_lock);
 586                 recent_table_flush(t);
 587                 spin_unlock_bh(&recent_lock);
 588                 return size;
 589         case '-': /* remove address */
 590                 add = false;
 591                 break;
 592         case '+': /* add address */
 593                 add = true;
 594                 break;
 595         default:
 596                 pr_info("Need \"+ip\", \"-ip\" or \"/\"\n");
 597                 return -EINVAL;
 598         }
 599
 600         ++c;
 601         --size;
 602         if (strnchr(c, size, ':') != NULL) {
 603                 family = NFPROTO_IPV6;
 604                 succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
 605         } else {
 606                 family = NFPROTO_IPV4;
 607                 succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
 608         }
 609
 610         if (!succ) {
 611                 pr_info("illegal address written to procfs\n");
 612                 return -EINVAL;
 613         }
 614
 615         spin_lock_bh(&recent_lock);
 616         e = recent_entry_lookup(t, &addr, family, 0);
 617         if (e == NULL) {
 618                 if (add)
 619                         recent_entry_init(t, &addr, family, 0);
 620         } else {
 621                 if (add)
 622                         recent_entry_update(t, e);
 623                 else
 624                         recent_entry_remove(t, e);
 625         }
 626         spin_unlock_bh(&recent_lock);
 627         /* Note we removed one above */
 628         *loff += size + 1;
 629         return size + 1;
 630 }
 631
 632 static const struct file_operations recent_mt_fops = {
 633         .open    = recent_seq_open,
 634         .read    = seq_read,
 635         .write   = recent_mt_proc_write,
 636         .release = seq_release_private,
 637         .owner   = THIS_MODULE,
 638         .llseek = seq_lseek,
 639 };
 640
 641 static int __net_init recent_proc_net_init(struct net *net)
 642 {
 643         struct recent_net *recent_net = recent_pernet(net);
 644
 645         recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
 646         if (!recent_net->xt_recent)
 647                 return -ENOMEM;
 648         return 0;
 649 }
 650
 651 static void __net_exit recent_proc_net_exit(struct net *net)
 652 {
 653         struct recent_net *recent_net = recent_pernet(net);
 654         struct recent_table *t;
 655
 656         /* recent_net_exit() is called before recent_mt_destroy(). Make sure
 657          * that the parent xt_recent proc entry is is empty before trying to
 658          * remove it.
 659          */
 660         spin_lock_bh(&recent_lock);
 661         list_for_each_entry(t, &recent_net->tables, list)
 662                 remove_proc_entry(t->name, recent_net->xt_recent);
 663
 664         recent_net->xt_recent = NULL;
 665         spin_unlock_bh(&recent_lock);
 666
 667         remove_proc_entry("xt_recent", net->proc_net);
 668 }
 669 #else
 670 static inline int recent_proc_net_init(struct net *net)
 671 {
 672         return 0;
 673 }
 674
 675 static inline void recent_proc_net_exit(struct net *net)
 676 {
 677 }
 678 #endif /* CONFIG_PROC_FS */
 679
 680 static int __net_init recent_net_init(struct net *net)
 681 {
 682         struct recent_net *recent_net = recent_pernet(net);
 683
 684         INIT_LIST_HEAD(&recent_net->tables);
 685         return recent_proc_net_init(net);
 686 }
 687
 688 static void __net_exit recent_net_exit(struct net *net)
 689 {
 690         recent_proc_net_exit(net);
 691 }
 692
 693 static struct pernet_operations recent_net_ops = {
 694         .init   = recent_net_init,
 695         .exit   = recent_net_exit,
 696         .id     = &recent_net_id,
 697         .size   = sizeof(struct recent_net),
 698 };
 699
 700 static struct xt_match recent_mt_reg[] __read_mostly = {
 701         {
 702                 .name       = "recent",
 703                 .revision   = 0,
 704                 .family     = NFPROTO_IPV4,
 705                 .match      = recent_mt,
 706                 .matchsize  = sizeof(struct xt_recent_mtinfo),
 707                 .checkentry = recent_mt_check_v0,
 708                 .destroy    = recent_mt_destroy,
 709                 .me         = THIS_MODULE,
 710         },
 711         {
 712                 .name       = "recent",
 713                 .revision   = 0,
 714                 .family     = NFPROTO_IPV6,
 715                 .match      = recent_mt,
 716                 .matchsize  = sizeof(struct xt_recent_mtinfo),
 717                 .checkentry = recent_mt_check_v0,
 718                 .destroy    = recent_mt_destroy,
 719                 .me         = THIS_MODULE,
 720         },
 721         {
 722                 .name       = "recent",
 723                 .revision   = 1,
 724                 .family     = NFPROTO_IPV4,
 725                 .match      = recent_mt,
 726                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
 727                 .checkentry = recent_mt_check_v1,
 728                 .destroy    = recent_mt_destroy,
 729                 .me         = THIS_MODULE,
 730         },
 731         {
 732                 .name       = "recent",
 733                 .revision   = 1,
 734                 .family     = NFPROTO_IPV6,
 735                 .match      = recent_mt,
 736                 .matchsize  = sizeof(struct xt_recent_mtinfo_v1),
 737                 .checkentry = recent_mt_check_v1,
 738                 .destroy    = recent_mt_destroy,
 739                 .me         = THIS_MODULE,
 740         }
 741 };
 742
 743 static int __init recent_mt_init(void)
 744 {
 745         int err;
 746
 747         BUILD_BUG_ON_NOT_POWER_OF_2(XT_RECENT_MAX_NSTAMPS);
 748
 749         if (!ip_list_tot || ip_pkt_list_tot >= XT_RECENT_MAX_NSTAMPS)
 750                 return -EINVAL;
 751         ip_list_hash_size = 1 << fls(ip_list_tot);
 752
 753         err = register_pernet_subsys(&recent_net_ops);
 754         if (err)
 755                 return err;
 756         err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 757         if (err)
 758                 unregister_pernet_subsys(&recent_net_ops);
 759         return err;
 760 }
 761
 762 static void __exit recent_mt_exit(void)
 763 {
 764         xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
 765         unregister_pernet_subsys(&recent_net_ops);
 766 }
 767
 768 module_init(recent_mt_init);
 769 module_exit(recent_mt_exit);