linux/net/netfilter/xt_recent.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
   4 * Copyright \xC2\xA9 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
  36MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  37MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
  38MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
  39MODULE_LICENSE("GPL");
  40MODULE_ALIAS("ipt_recent");
  41MODULE_ALIAS("ip6t_recent");
  42
  43static unsigned int ip_list_tot __read_mostly = 100;
  44static unsigned int ip_list_hash_size __read_mostly;
  45static unsigned int ip_list_perms __read_mostly = 0644;
  46static unsigned int ip_list_uid __read_mostly;
  47static unsigned int ip_list_gid __read_mostly;
  48module_param(ip_list_tot, uint, 0400);
  49module_param(ip_list_hash_size, uint, 0400);
  50module_param(ip_list_perms, uint, 0400);
  51module_param(ip_list_uid, uint, 0644);
  52module_param(ip_list_gid, uint, 0644);
  53MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
  54MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
  55MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
  56MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
  57MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
  58
  59/* retained for backwards compatibility */
  60static unsigned int ip_pkt_list_tot __read_mostly;
  61module_param(ip_pkt_list_tot, uint, 0400);
  62MODULE_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
  66struct 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
  77struct 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
  88struct recent_net {
  89        struct list_head        tables;
  90#ifdef CONFIG_PROC_FS
  91        struct proc_dir_entry   *xt_recent;
  92#endif
  93};
  94
  95static unsigned int recent_net_id __read_mostly;
  96
  97static inline struct recent_net *recent_pernet(struct net *net)
  98{
  99        return net_generic(net, recent_net_id);
 100}
 101
 102static DEFINE_SPINLOCK(recent_lock);
 103static DEFINE_MUTEX(recent_mutex);
 104
 105#ifdef CONFIG_PROC_FS
 106static const struct proc_ops recent_mt_proc_ops;
 107#endif
 108
 109static u_int32_t hash_rnd __read_mostly;
 110
 111static 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
 117static 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
 123static struct recent_entry *
 124recent_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
 144static 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 */
 155static void recent_entry_reap(struct recent_table *t, unsigned long time,
 156                              struct recent_entry *working, bool update)
 157{
 158        struct recent_entry *e;
 159
 160        /*
 161         * The head of the LRU list is always the oldest entry.
 162         */
 163        e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 164
 165        /*
 166         * Do not reap the entry which are going to be updated.
 167         */
 168        if (e == working && update)
 169                return;
 170
 171        /*
 172         * The last time stamp is the most recent.
 173         */
 174        if (time_after(time, e->stamps[e->index-1]))
 175                recent_entry_remove(t, e);
 176}
 177
 178static struct recent_entry *
 179recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
 180                  u_int16_t family, u_int8_t ttl)
 181{
 182        struct recent_entry *e;
 183        unsigned int nstamps_max = t->nstamps_max_mask;
 184
 185        if (t->entries >= ip_list_tot) {
 186                e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
 187                recent_entry_remove(t, e);
 188        }
 189
 190        nstamps_max += 1;
 191        e = kmalloc(struct_size(e, stamps, nstamps_max), GFP_ATOMIC);
 192        if (e == NULL)
 193                return NULL;
 194        memcpy(&e->addr, addr, sizeof(e->addr));
 195        e->ttl       = ttl;
 196        e->stamps[0] = jiffies;
 197        e->nstamps   = 1;
 198        e->index     = 1;
 199        e->family    = family;
 200        if (family == NFPROTO_IPV4)
 201                list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
 202        else
 203                list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
 204        list_add_tail(&e->lru_list, &t->lru_list);
 205        t->entries++;
 206        return e;
 207}
 208
 209static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
 210{
 211        e->index &= t->nstamps_max_mask;
 212        e->stamps[e->index++] = jiffies;
 213        if (e->index > e->nstamps)
 214                e->nstamps = e->index;
 215        list_move_tail(&e->lru_list, &t->lru_list);
 216}
 217
 218static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
 219                                                const char *name)
 220{
 221        struct recent_table *t;
 222
 223        list_for_each_entry(t, &recent_net->tables, list)
 224                if (!strcmp(t->name, name))
 225                        return t;
 226        return NULL;
 227}
 228
 229static void recent_table_flush(struct recent_table *t)
 230{
 231        struct recent_entry *e, *next;
 232        unsigned int i;
 233
 234        for (i = 0; i < ip_list_hash_size; i++)
 235                list_for_each_entry_safe(e, next, &t->iphash[i], list)
 236                        recent_entry_remove(t, e);
 237}
 238
 239static bool
 240recent_mt(const struct sk_buff *skb, struct xt_action_param *par)
 241{
 242        struct net *net = xt_net(par);
 243        struct recent_net *recent_net = recent_pernet(net);
 244        const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 245        struct recent_table *t;
 246        struct recent_entry *e;
 247        union nf_inet_addr addr = {}, addr_mask;
 248        u_int8_t ttl;
 249        bool ret = info->invert;
 250
 251        if (xt_family(par) == NFPROTO_IPV4) {
 252                const struct iphdr *iph = ip_hdr(skb);
 253
 254                if (info->side == XT_RECENT_DEST)
 255                        addr.ip = iph->daddr;
 256                else
 257                        addr.ip = iph->saddr;
 258
 259                ttl = iph->ttl;
 260        } else {
 261                const struct ipv6hdr *iph = ipv6_hdr(skb);
 262
 263                if (info->side == XT_RECENT_DEST)
 264                        memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
 265                else
 266                        memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
 267
 268                ttl = iph->hop_limit;
 269        }
 270
 271        /* use TTL as seen before forwarding */
 272        if (xt_out(par) != NULL &&
 273            (!skb->sk || !net_eq(net, sock_net(skb->sk))))
 274                ttl++;
 275
 276        spin_lock_bh(&recent_lock);
 277        t = recent_table_lookup(recent_net, info->name);
 278
 279        nf_inet_addr_mask(&addr, &addr_mask, &t->mask);
 280
 281        e = recent_entry_lookup(t, &addr_mask, xt_family(par),
 282                                (info->check_set & XT_RECENT_TTL) ? ttl : 0);
 283        if (e == NULL) {
 284                if (!(info->check_set & XT_RECENT_SET))
 285                        goto out;
 286                e = recent_entry_init(t, &addr_mask, xt_family(par), ttl);
 287                if (e == NULL)
 288                        par->hotdrop = true;
 289                ret = !ret;
 290                goto out;
 291        }
 292
 293        if (info->check_set & XT_RECENT_SET)
 294                ret = !ret;
 295        else if (info->check_set & XT_RECENT_REMOVE) {
 296                recent_entry_remove(t, e);
 297                ret = !ret;
 298        } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
 299                unsigned long time = jiffies - info->seconds * HZ;
 300                unsigned int i, hits = 0;
 301
 302                for (i = 0; i < e->nstamps; i++) {
 303                        if (info->seconds && time_after(time, e->stamps[i]))
 304                                continue;
 305                        if (!info->hit_count || ++hits >= info->hit_count) {
 306                                ret = !ret;
 307                                break;
 308                        }
 309                }
 310
 311                /* info->seconds must be non-zero */
 312                if (info->check_set & XT_RECENT_REAP)
 313                        recent_entry_reap(t, time, e,
 314                                info->check_set & XT_RECENT_UPDATE && ret);
 315        }
 316
 317        if (info->check_set & XT_RECENT_SET ||
 318            (info->check_set & XT_RECENT_UPDATE && ret)) {
 319                recent_entry_update(t, e);
 320                e->ttl = ttl;
 321        }
 322out:
 323        spin_unlock_bh(&recent_lock);
 324        return ret;
 325}
 326
 327static void recent_table_free(void *addr)
 328{
 329        kvfree(addr);
 330}
 331
 332static int recent_mt_check(const struct xt_mtchk_param *par,
 333                           const struct xt_recent_mtinfo_v1 *info)
 334{
 335        struct recent_net *recent_net = recent_pernet(par->net);
 336        struct recent_table *t;
 337#ifdef CONFIG_PROC_FS
 338        struct proc_dir_entry *pde;
 339        kuid_t uid;
 340        kgid_t gid;
 341#endif
 342        unsigned int nstamp_mask;
 343        unsigned int i;
 344        int ret = -EINVAL;
 345
 346        net_get_random_once(&hash_rnd, sizeof(hash_rnd));
 347
 348        if (info->check_set & ~XT_RECENT_VALID_FLAGS) {
 349                pr_info_ratelimited("Unsupported userspace flags (%08x)\n",
 350                                    info->check_set);
 351                return -EINVAL;
 352        }
 353        if (hweight8(info->check_set &
 354                     (XT_RECENT_SET | XT_RECENT_REMOVE |
 355                      XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
 356                return -EINVAL;
 357        if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
 358            (info->seconds || info->hit_count ||
 359            (info->check_set & XT_RECENT_MODIFIERS)))
 360                return -EINVAL;
 361        if ((info->check_set & XT_RECENT_REAP) && !info->seconds)
 362                return -EINVAL;
 363        if (info->hit_count >= XT_RECENT_MAX_NSTAMPS) {
 364                pr_info_ratelimited("hitcount (%u) is larger than allowed maximum (%u)\n",
 365                                    info->hit_count, XT_RECENT_MAX_NSTAMPS - 1);
 366                return -EINVAL;
 367        }
 368        ret = xt_check_proc_name(info->name, sizeof(info->name));
 369        if (ret)
 370                return ret;
 371
 372        if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot)
 373                nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1;
 374        else if (info->hit_count)
 375                nstamp_mask = roundup_pow_of_two(info->hit_count) - 1;
 376        else
 377                nstamp_mask = 32 - 1;
 378
 379        mutex_lock(&recent_mutex);
 380        t = recent_table_lookup(recent_net, info->name);
 381        if (t != NULL) {
 382                if (nstamp_mask > t->nstamps_max_mask) {
 383                        spin_lock_bh(&recent_lock);
 384                        recent_table_flush(t);
 385                        t->nstamps_max_mask = nstamp_mask;
 386                        spin_unlock_bh(&recent_lock);
 387                }
 388
 389                t->refcnt++;
 390                ret = 0;
 391                goto out;
 392        }
 393
 394        t = kvzalloc(struct_size(t, iphash, ip_list_hash_size), GFP_KERNEL);
 395        if (t == NULL) {
 396                ret = -ENOMEM;
 397                goto out;
 398        }
 399        t->refcnt = 1;
 400        t->nstamps_max_mask = nstamp_mask;
 401
 402        memcpy(&t->mask, &info->mask, sizeof(t->mask));
 403        strcpy(t->name, info->name);
 404        INIT_LIST_HEAD(&t->lru_list);
 405        for (i = 0; i < ip_list_hash_size; i++)
 406                INIT_LIST_HEAD(&t->iphash[i]);
 407#ifdef CONFIG_PROC_FS
 408        uid = make_kuid(&init_user_ns, ip_list_uid);
 409        gid = make_kgid(&init_user_ns, ip_list_gid);
 410        if (!uid_valid(uid) || !gid_valid(gid)) {
 411                recent_table_free(t);
 412                ret = -EINVAL;
 413                goto out;
 414        }
 415        pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
 416                               &recent_mt_proc_ops, t);
 417        if (pde == NULL) {
 418                recent_table_free(t);
 419                ret = -ENOMEM;
 420                goto out;
 421        }
 422        proc_set_user(pde, uid, gid);
 423#endif
 424        spin_lock_bh(&recent_lock);
 425        list_add_tail(&t->list, &recent_net->tables);
 426        spin_unlock_bh(&recent_lock);
 427        ret = 0;
 428out:
 429        mutex_unlock(&recent_mutex);
 430        return ret;
 431}
 432
 433static int recent_mt_check_v0(const struct xt_mtchk_param *par)
 434{
 435        const struct xt_recent_mtinfo_v0 *info_v0 = par->matchinfo;
 436        struct xt_recent_mtinfo_v1 info_v1;
 437
 438        /* Copy revision 0 structure to revision 1 */
 439        memcpy(&info_v1, info_v0, sizeof(struct xt_recent_mtinfo));
 440        /* Set default mask to ensure backward compatible behaviour */
 441        memset(info_v1.mask.all, 0xFF, sizeof(info_v1.mask.all));
 442
 443        return recent_mt_check(par, &info_v1);
 444}
 445
 446static int recent_mt_check_v1(const struct xt_mtchk_param *par)
 447{
 448        return recent_mt_check(par, par->matchinfo);
 449}
 450
 451static void recent_mt_destroy(const struct xt_mtdtor_param *par)
 452{
 453        struct recent_net *recent_net = recent_pernet(par->net);
 454        const struct xt_recent_mtinfo_v1 *info = par->matchinfo;
 455        struct recent_table *t;
 456
 457        mutex_lock(&recent_mutex);
 458        t = recent_table_lookup(recent_net, info->name);
 459        if (--t->refcnt == 0) {
 460                spin_lock_bh(&recent_lock);
 461                list_del(&t->list);
 462                spin_unlock_bh(&recent_lock);
 463#ifdef CONFIG_PROC_FS
 464                if (recent_net->xt_recent != NULL)
 465                        remove_proc_entry(t->name, recent_net->xt_recent);
 466#endif
 467                recent_table_flush(t);
 468                recent_table_free(t);
 469        }
 470        mutex_unlock(&recent_mutex);
 471}
 472
 473#ifdef CONFIG_PROC_FS
 474struct recent_iter_state {
 475        const struct recent_table *table;
 476        unsigned int            bucket;
 477};
 478
 479static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
 480        __acquires(recent_lock)
 481{
 482        struct recent_iter_state *st = seq->private;
 483        const struct recent_table *t = st->table;
 484        struct recent_entry *e;
 485        loff_t p = *pos;
 486
 487        spin_lock_bh(&recent_lock);
 488
 489        for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
 490                list_for_each_entry(e, &t->iphash[st->bucket], list)
 491                        if (p-- == 0)
 492                                return e;
 493        return NULL;
 494}
 495
 496static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 497{
 498        struct recent_iter_state *st = seq->private;
 499        const struct recent_table *t = st->table;
 500        const struct recent_entry *e = v;
 501        const struct list_head *head = e->list.next;
 502
 503        (*pos)++;
 504        while (head == &t->iphash[st->bucket]) {
 505                if (++st->bucket >= ip_list_hash_size)
 506                        return NULL;
 507                head = t->iphash[st->bucket].next;
 508        }
 509        return list_entry(head, struct recent_entry, list);
 510}
 511
 512static void recent_seq_stop(struct seq_file *s, void *v)
 513        __releases(recent_lock)
 514{
 515        spin_unlock_bh(&recent_lock);
 516}
 517
 518static int recent_seq_show(struct seq_file *seq, void *v)
 519{
 520        const struct recent_entry *e = v;
 521        struct recent_iter_state *st = seq->private;
 522        const struct recent_table *t = st->table;
 523        unsigned int i;
 524
 525        i = (e->index - 1) & t->nstamps_max_mask;
 526
 527        if (e->family == NFPROTO_IPV4)
 528                seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
 529                           &e->addr.ip, e->ttl, e->stamps[i], e->index);
 530        else
 531                seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
 532                           &e->addr.in6, e->ttl, e->stamps[i], e->index);
 533        for (i = 0; i < e->nstamps; i++)
 534                seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
 535        seq_putc(seq, '\n');
 536        return 0;
 537}
 538
 539static const struct seq_operations recent_seq_ops = {
 540        .start          = recent_seq_start,
 541        .next           = recent_seq_next,
 542        .stop           = recent_seq_stop,
 543        .show           = recent_seq_show,
 544};
 545
 546static int recent_seq_open(struct inode *inode, struct file *file)
 547{
 548        struct recent_iter_state *st;
 549
 550        st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
 551        if (st == NULL)
 552                return -ENOMEM;
 553
 554        st->table    = PDE_DATA(inode);
 555        return 0;
 556}
 557
 558static ssize_t
 559recent_mt_proc_write(struct file *file, const char __user *input,
 560                     size_t size, loff_t *loff)
 561{
 562        struct recent_table *t = PDE_DATA(file_inode(file));
 563        struct recent_entry *e;
 564        char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
 565        const char *c = buf;
 566        union nf_inet_addr addr = {};
 567        u_int16_t family;
 568        bool add, succ;
 569
 570        if (size == 0)
 571                return 0;
 572        if (size > sizeof(buf))
 573                size = sizeof(buf);
 574        if (copy_from_user(buf, input, size) != 0)
 575                return -EFAULT;
 576
 577        /* Strict protocol! */
 578        if (*loff != 0)
 579                return -ESPIPE;
 580        switch (*c) {
 581        case '/': /* flush table */
 582                spin_lock_bh(&recent_lock);
 583                recent_table_flush(t);
 584                spin_unlock_bh(&recent_lock);
 585                return size;
 586        case '-': /* remove address */
 587                add = false;
 588                break;
 589        case '+': /* add address */
 590                add = true;
 591                break;
 592        default:
 593                pr_info_ratelimited("Need \"+ip\", \"-ip\" or \"/\"\n");
 594                return -EINVAL;
 595        }
 596
 597        ++c;
 598        --size;
 599        if (strnchr(c, size, ':') != NULL) {
 600                family = NFPROTO_IPV6;
 601                succ   = in6_pton(c, size, (void *)&addr, '\n', NULL);
 602        } else {
 603                family = NFPROTO_IPV4;
 604                succ   = in4_pton(c, size, (void *)&addr, '\n', NULL);
 605        }
 606
 607        if (!succ)
 608                return -EINVAL;
 609
 610        spin_lock_bh(&recent_lock);
 611        e = recent_entry_lookup(t, &addr, family, 0);
 612        if (e == NULL) {
 613                if (add)
 614                        recent_entry_init(t, &addr, family, 0);
 615        } else {
 616                if (add)
 617                        recent_entry_update(t, e);
 618                else
 619                        recent_entry_remove(t, e);
 620        }
 621        spin_unlock_bh(&recent_lock);
 622        /* Note we removed one above */
 623        *loff += size + 1;
 624        return size + 1;
 625}
 626
 627static const struct proc_ops recent_mt_proc_ops = {
 628        .proc_open      = recent_seq_open,
 629        .proc_read      = seq_read,
 630        .proc_write     = recent_mt_proc_write,
 631        .proc_release   = seq_release_private,
 632        .proc_lseek     = seq_lseek,
 633};
 634
 635static 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
 645static 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 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
 664static inline int recent_proc_net_init(struct net *net)
 665{
 666        return 0;
 667}
 668
 669static inline void recent_proc_net_exit(struct net *net)
 670{
 671}
 672#endif /* CONFIG_PROC_FS */
 673
 674static 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
 682static void __net_exit recent_net_exit(struct net *net)
 683{
 684        recent_proc_net_exit(net);
 685}
 686
 687static 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
 694static 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
 737static 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
 756static 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
 762module_init(recent_mt_init);
 763module_exit(recent_mt_exit);
 764