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   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
  14  *      - new API and handling of conntrack/nat helpers
  15  *      - now capable of multiple expectations for one master
  16  * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
  17  *      - add usage/reference counts to ip_conntrack_expect
  18  *      - export ip_conntrack[_expect]_{find_get,put} functions
  19  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  20  *      - generalize L3 protocol denendent part.
  21  * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  22  *      - add support various size of conntrack structures.
  23  * 26 Jan 2006: Harald Welte <laforge@netfilter.org>
  24  *      - restructure nf_conn (introduce nf_conn_help)
  25  *      - redesign 'features' how they were originally intended
  26  * 26 Feb 2006: Pablo Neira Ayuso <pablo@eurodev.net>
  27  *      - add support for L3 protocol module load on demand.
  28  *
  29  * Derived from net/ipv4/netfilter/ip_conntrack_core.c
  30  */
  31
  32 #include <linux/types.h>
  33 #include <linux/netfilter.h>
  34 #include <linux/module.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/vmalloc.h>
  38 #include <linux/stddef.h>
  39 #include <linux/slab.h>
  40 #include <linux/random.h>
  41 #include <linux/jhash.h>
  42 #include <linux/err.h>
  43 #include <linux/percpu.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/notifier.h>
  46 #include <linux/kernel.h>
  47 #include <linux/netdevice.h>
  48 #include <linux/socket.h>
  49
  50 #include <net/netfilter/nf_conntrack.h>
  51 #include <net/netfilter/nf_conntrack_l3proto.h>
  52 #include <net/netfilter/nf_conntrack_l4proto.h>
  53 #include <net/netfilter/nf_conntrack_expect.h>
  54 #include <net/netfilter/nf_conntrack_helper.h>
  55 #include <net/netfilter/nf_conntrack_core.h>
  56
  57 #define NF_CONNTRACK_VERSION    "0.5.0"
  58
  59 #if 0
  60 #define DEBUGP printk
  61 #else
  62 #define DEBUGP(format, args...)
  63 #endif
  64
  65 DEFINE_RWLOCK(nf_conntrack_lock);
  66 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  67
  68 /* nf_conntrack_standalone needs this */
  69 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  70 EXPORT_SYMBOL_GPL(nf_conntrack_count);
  71
  72 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
  73 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed);
  74
  75 unsigned int nf_conntrack_htable_size __read_mostly;
  76 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  77
  78 int nf_conntrack_max __read_mostly;
  79 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  80
  81 struct list_head *nf_conntrack_hash __read_mostly;
  82 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  83
  84 struct nf_conn nf_conntrack_untracked __read_mostly;
  85 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
  86
  87 unsigned int nf_ct_log_invalid __read_mostly;
  88 LIST_HEAD(unconfirmed);
  89 static int nf_conntrack_vmalloc __read_mostly;
  90
  91 static unsigned int nf_conntrack_next_id;
  92
  93 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  94 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  95
  96 /*
  97  * This scheme offers various size of "struct nf_conn" dependent on
  98  * features(helper, nat, ...)
  99  */
 100
 101 #define NF_CT_FEATURES_NAMELEN  256
 102 static struct {
 103         /* name of slab cache. printed in /proc/slabinfo */
 104         char *name;
 105
 106         /* size of slab cache */
 107         size_t size;
 108
 109         /* slab cache pointer */
 110         kmem_cache_t *cachep;
 111
 112         /* allocated slab cache + modules which uses this slab cache */
 113         int use;
 114
 115 } nf_ct_cache[NF_CT_F_NUM];
 116
 117 /* protect members of nf_ct_cache except of "use" */
 118 DEFINE_RWLOCK(nf_ct_cache_lock);
 119
 120 /* This avoids calling kmem_cache_create() with same name simultaneously */
 121 static DEFINE_MUTEX(nf_ct_cache_mutex);
 122
 123 static int nf_conntrack_hash_rnd_initted;
 124 static unsigned int nf_conntrack_hash_rnd;
 125
 126 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 127                                   unsigned int size, unsigned int rnd)
 128 {
 129         unsigned int a, b;
 130         a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
 131                   ((tuple->src.l3num) << 16) | tuple->dst.protonum);
 132         b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
 133                         (tuple->src.u.all << 16) | tuple->dst.u.all);
 134
 135         return jhash_2words(a, b, rnd) % size;
 136 }
 137
 138 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
 139 {
 140         return __hash_conntrack(tuple, nf_conntrack_htable_size,
 141                                 nf_conntrack_hash_rnd);
 142 }
 143
 144 int nf_conntrack_register_cache(u_int32_t features, const char *name,
 145                                 size_t size)
 146 {
 147         int ret = 0;
 148         char *cache_name;
 149         kmem_cache_t *cachep;
 150
 151         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
 152                features, name, size);
 153
 154         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
 155                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
 156                         features);
 157                 return -EINVAL;
 158         }
 159
 160         mutex_lock(&nf_ct_cache_mutex);
 161
 162         write_lock_bh(&nf_ct_cache_lock);
 163         /* e.g: multiple helpers are loaded */
 164         if (nf_ct_cache[features].use > 0) {
 165                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
 166                 if ((!strncmp(nf_ct_cache[features].name, name,
 167                               NF_CT_FEATURES_NAMELEN))
 168                     && nf_ct_cache[features].size == size) {
 169                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
 170                         nf_ct_cache[features].use++;
 171                         ret = 0;
 172                 } else
 173                         ret = -EBUSY;
 174
 175                 write_unlock_bh(&nf_ct_cache_lock);
 176                 mutex_unlock(&nf_ct_cache_mutex);
 177                 return ret;
 178         }
 179         write_unlock_bh(&nf_ct_cache_lock);
 180
 181         /*
 182          * The memory space for name of slab cache must be alive until
 183          * cache is destroyed.
 184          */
 185         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
 186         if (cache_name == NULL) {
 187                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
 188                 ret = -ENOMEM;
 189                 goto out_up_mutex;
 190         }
 191
 192         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
 193                                                 >= NF_CT_FEATURES_NAMELEN) {
 194                 printk("nf_conntrack_register_cache: name too long\n");
 195                 ret = -EINVAL;
 196                 goto out_free_name;
 197         }
 198
 199         cachep = kmem_cache_create(cache_name, size, 0, 0,
 200                                    NULL, NULL);
 201         if (!cachep) {
 202                 printk("nf_conntrack_register_cache: Can't create slab cache "
 203                        "for the features = 0x%x\n", features);
 204                 ret = -ENOMEM;
 205                 goto out_free_name;
 206         }
 207
 208         write_lock_bh(&nf_ct_cache_lock);
 209         nf_ct_cache[features].use = 1;
 210         nf_ct_cache[features].size = size;
 211         nf_ct_cache[features].cachep = cachep;
 212         nf_ct_cache[features].name = cache_name;
 213         write_unlock_bh(&nf_ct_cache_lock);
 214
 215         goto out_up_mutex;
 216
 217 out_free_name:
 218         kfree(cache_name);
 219 out_up_mutex:
 220         mutex_unlock(&nf_ct_cache_mutex);
 221         return ret;
 222 }
 223 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache);
 224
 225 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
 226 void nf_conntrack_unregister_cache(u_int32_t features)
 227 {
 228         kmem_cache_t *cachep;
 229         char *name;
 230
 231         /*
 232          * This assures that kmem_cache_create() isn't called before destroying
 233          * slab cache.
 234          */
 235         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
 236         mutex_lock(&nf_ct_cache_mutex);
 237
 238         write_lock_bh(&nf_ct_cache_lock);
 239         if (--nf_ct_cache[features].use > 0) {
 240                 write_unlock_bh(&nf_ct_cache_lock);
 241                 mutex_unlock(&nf_ct_cache_mutex);
 242                 return;
 243         }
 244         cachep = nf_ct_cache[features].cachep;
 245         name = nf_ct_cache[features].name;
 246         nf_ct_cache[features].cachep = NULL;
 247         nf_ct_cache[features].name = NULL;
 248         nf_ct_cache[features].size = 0;
 249         write_unlock_bh(&nf_ct_cache_lock);
 250
 251         synchronize_net();
 252
 253         kmem_cache_destroy(cachep);
 254         kfree(name);
 255
 256         mutex_unlock(&nf_ct_cache_mutex);
 257 }
 258 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache);
 259
 260 int
 261 nf_ct_get_tuple(const struct sk_buff *skb,
 262                 unsigned int nhoff,
 263                 unsigned int dataoff,
 264                 u_int16_t l3num,
 265                 u_int8_t protonum,
 266                 struct nf_conntrack_tuple *tuple,
 267                 const struct nf_conntrack_l3proto *l3proto,
 268                 const struct nf_conntrack_l4proto *l4proto)
 269 {
 270         NF_CT_TUPLE_U_BLANK(tuple);
 271
 272         tuple->src.l3num = l3num;
 273         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 274                 return 0;
 275
 276         tuple->dst.protonum = protonum;
 277         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 278
 279         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 280 }
 281 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 282
 283 int
 284 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 285                    const struct nf_conntrack_tuple *orig,
 286                    const struct nf_conntrack_l3proto *l3proto,
 287                    const struct nf_conntrack_l4proto *l4proto)
 288 {
 289         NF_CT_TUPLE_U_BLANK(inverse);
 290
 291         inverse->src.l3num = orig->src.l3num;
 292         if (l3proto->invert_tuple(inverse, orig) == 0)
 293                 return 0;
 294
 295         inverse->dst.dir = !orig->dst.dir;
 296
 297         inverse->dst.protonum = orig->dst.protonum;
 298         return l4proto->invert_tuple(inverse, orig);
 299 }
 300 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 301
 302 static void
 303 clean_from_lists(struct nf_conn *ct)
 304 {
 305         DEBUGP("clean_from_lists(%p)\n", ct);
 306         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 307         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
 308
 309         /* Destroy all pending expectations */
 310         nf_ct_remove_expectations(ct);
 311 }
 312
 313 static void
 314 destroy_conntrack(struct nf_conntrack *nfct)
 315 {
 316         struct nf_conn *ct = (struct nf_conn *)nfct;
 317         struct nf_conn_help *help = nfct_help(ct);
 318         struct nf_conntrack_l3proto *l3proto;
 319         struct nf_conntrack_l4proto *l4proto;
 320
 321         DEBUGP("destroy_conntrack(%p)\n", ct);
 322         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 323         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 324
 325         nf_conntrack_event(IPCT_DESTROY, ct);
 326         set_bit(IPS_DYING_BIT, &ct->status);
 327
 328         if (help && help->helper && help->helper->destroy)
 329                 help->helper->destroy(ct);
 330
 331         /* To make sure we don't get any weird locking issues here:
 332          * destroy_conntrack() MUST NOT be called with a write lock
 333          * to nf_conntrack_lock!!! -HW */
 334         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
 335         if (l3proto && l3proto->destroy)
 336                 l3proto->destroy(ct);
 337
 338         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 339         if (l4proto && l4proto->destroy)
 340                 l4proto->destroy(ct);
 341
 342         if (nf_conntrack_destroyed)
 343                 nf_conntrack_destroyed(ct);
 344
 345         write_lock_bh(&nf_conntrack_lock);
 346         /* Expectations will have been removed in clean_from_lists,
 347          * except TFTP can create an expectation on the first packet,
 348          * before connection is in the list, so we need to clean here,
 349          * too. */
 350         nf_ct_remove_expectations(ct);
 351
 352         /* We overload first tuple to link into unconfirmed list. */
 353         if (!nf_ct_is_confirmed(ct)) {
 354                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 355                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 356         }
 357
 358         NF_CT_STAT_INC(delete);
 359         write_unlock_bh(&nf_conntrack_lock);
 360
 361         if (ct->master)
 362                 nf_ct_put(ct->master);
 363
 364         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 365         nf_conntrack_free(ct);
 366 }
 367
 368 static void death_by_timeout(unsigned long ul_conntrack)
 369 {
 370         struct nf_conn *ct = (void *)ul_conntrack;
 371
 372         write_lock_bh(&nf_conntrack_lock);
 373         /* Inside lock so preempt is disabled on module removal path.
 374          * Otherwise we can get spurious warnings. */
 375         NF_CT_STAT_INC(delete_list);
 376         clean_from_lists(ct);
 377         write_unlock_bh(&nf_conntrack_lock);
 378         nf_ct_put(ct);
 379 }
 380
 381 struct nf_conntrack_tuple_hash *
 382 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 383                     const struct nf_conn *ignored_conntrack)
 384 {
 385         struct nf_conntrack_tuple_hash *h;
 386         unsigned int hash = hash_conntrack(tuple);
 387
 388         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
 389                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 390                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 391                         NF_CT_STAT_INC(found);
 392                         return h;
 393                 }
 394                 NF_CT_STAT_INC(searched);
 395         }
 396
 397         return NULL;
 398 }
 399 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 400
 401 /* Find a connection corresponding to a tuple. */
 402 struct nf_conntrack_tuple_hash *
 403 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
 404                       const struct nf_conn *ignored_conntrack)
 405 {
 406         struct nf_conntrack_tuple_hash *h;
 407
 408         read_lock_bh(&nf_conntrack_lock);
 409         h = __nf_conntrack_find(tuple, ignored_conntrack);
 410         if (h)
 411                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 412         read_unlock_bh(&nf_conntrack_lock);
 413
 414         return h;
 415 }
 416 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 417
 418 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 419                                        unsigned int hash,
 420                                        unsigned int repl_hash)
 421 {
 422         ct->id = ++nf_conntrack_next_id;
 423         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
 424                  &nf_conntrack_hash[hash]);
 425         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
 426                  &nf_conntrack_hash[repl_hash]);
 427 }
 428
 429 void nf_conntrack_hash_insert(struct nf_conn *ct)
 430 {
 431         unsigned int hash, repl_hash;
 432
 433         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 434         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 435
 436         write_lock_bh(&nf_conntrack_lock);
 437         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 438         write_unlock_bh(&nf_conntrack_lock);
 439 }
 440 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 441
 442 /* Confirm a connection given skb; places it in hash table */
 443 int
 444 __nf_conntrack_confirm(struct sk_buff **pskb)
 445 {
 446         unsigned int hash, repl_hash;
 447         struct nf_conntrack_tuple_hash *h;
 448         struct nf_conn *ct;
 449         struct nf_conn_help *help;
 450         enum ip_conntrack_info ctinfo;
 451
 452         ct = nf_ct_get(*pskb, &ctinfo);
 453
 454         /* ipt_REJECT uses nf_conntrack_attach to attach related
 455            ICMP/TCP RST packets in other direction.  Actual packet
 456            which created connection will be IP_CT_NEW or for an
 457            expected connection, IP_CT_RELATED. */
 458         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 459                 return NF_ACCEPT;
 460
 461         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 462         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 463
 464         /* We're not in hash table, and we refuse to set up related
 465            connections for unconfirmed conns.  But packet copies and
 466            REJECT will give spurious warnings here. */
 467         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 468
 469         /* No external references means noone else could have
 470            confirmed us. */
 471         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 472         DEBUGP("Confirming conntrack %p\n", ct);
 473
 474         write_lock_bh(&nf_conntrack_lock);
 475
 476         /* See if there's one in the list already, including reverse:
 477            NAT could have grabbed it without realizing, since we're
 478            not in the hash.  If there is, we lost race. */
 479         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
 480                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 481                                       &h->tuple))
 482                         goto out;
 483         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
 484                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 485                                       &h->tuple))
 486                         goto out;
 487
 488         /* Remove from unconfirmed list */
 489         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 490
 491         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 492         /* Timer relative to confirmation time, not original
 493            setting time, otherwise we'd get timer wrap in
 494            weird delay cases. */
 495         ct->timeout.expires += jiffies;
 496         add_timer(&ct->timeout);
 497         atomic_inc(&ct->ct_general.use);
 498         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 499         NF_CT_STAT_INC(insert);
 500         write_unlock_bh(&nf_conntrack_lock);
 501         help = nfct_help(ct);
 502         if (help && help->helper)
 503                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 504 #ifdef CONFIG_NF_NAT_NEEDED
 505         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 506             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 507                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 508 #endif
 509         nf_conntrack_event_cache(master_ct(ct) ?
 510                                  IPCT_RELATED : IPCT_NEW, *pskb);
 511         return NF_ACCEPT;
 512
 513 out:
 514         NF_CT_STAT_INC(insert_failed);
 515         write_unlock_bh(&nf_conntrack_lock);
 516         return NF_DROP;
 517 }
 518 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 519
 520 /* Returns true if a connection correspondings to the tuple (required
 521    for NAT). */
 522 int
 523 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 524                          const struct nf_conn *ignored_conntrack)
 525 {
 526         struct nf_conntrack_tuple_hash *h;
 527
 528         read_lock_bh(&nf_conntrack_lock);
 529         h = __nf_conntrack_find(tuple, ignored_conntrack);
 530         read_unlock_bh(&nf_conntrack_lock);
 531
 532         return h != NULL;
 533 }
 534 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 535
 536 /* There's a small race here where we may free a just-assured
 537    connection.  Too bad: we're in trouble anyway. */
 538 static int early_drop(struct list_head *chain)
 539 {
 540         /* Traverse backwards: gives us oldest, which is roughly LRU */
 541         struct nf_conntrack_tuple_hash *h;
 542         struct nf_conn *ct = NULL, *tmp;
 543         int dropped = 0;
 544
 545         read_lock_bh(&nf_conntrack_lock);
 546         list_for_each_entry_reverse(h, chain, list) {
 547                 tmp = nf_ct_tuplehash_to_ctrack(h);
 548                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
 549                         ct = tmp;
 550                         atomic_inc(&ct->ct_general.use);
 551                         break;
 552                 }
 553         }
 554         read_unlock_bh(&nf_conntrack_lock);
 555
 556         if (!ct)
 557                 return dropped;
 558
 559         if (del_timer(&ct->timeout)) {
 560                 death_by_timeout((unsigned long)ct);
 561                 dropped = 1;
 562                 NF_CT_STAT_INC(early_drop);
 563         }
 564         nf_ct_put(ct);
 565         return dropped;
 566 }
 567
 568 static struct nf_conn *
 569 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 570                      const struct nf_conntrack_tuple *repl,
 571                      const struct nf_conntrack_l3proto *l3proto,
 572                      u_int32_t features)
 573 {
 574         struct nf_conn *conntrack = NULL;
 575         struct nf_conntrack_helper *helper;
 576
 577         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 578                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 579                 nf_conntrack_hash_rnd_initted = 1;
 580         }
 581
 582         /* We don't want any race condition at early drop stage */
 583         atomic_inc(&nf_conntrack_count);
 584
 585         if (nf_conntrack_max
 586             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 587                 unsigned int hash = hash_conntrack(orig);
 588                 /* Try dropping from this hash chain. */
 589                 if (!early_drop(&nf_conntrack_hash[hash])) {
 590                         atomic_dec(&nf_conntrack_count);
 591                         if (net_ratelimit())
 592                                 printk(KERN_WARNING
 593                                        "nf_conntrack: table full, dropping"
 594                                        " packet.\n");
 595                         return ERR_PTR(-ENOMEM);
 596                 }
 597         }
 598
 599         /*  find features needed by this conntrack. */
 600         features |= l3proto->get_features(orig);
 601
 602         /* FIXME: protect helper list per RCU */
 603         read_lock_bh(&nf_conntrack_lock);
 604         helper = __nf_ct_helper_find(repl);
 605         /* NAT might want to assign a helper later */
 606         if (helper || features & NF_CT_F_NAT)
 607                 features |= NF_CT_F_HELP;
 608         read_unlock_bh(&nf_conntrack_lock);
 609
 610         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 611
 612         read_lock_bh(&nf_ct_cache_lock);
 613
 614         if (unlikely(!nf_ct_cache[features].use)) {
 615                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
 616                         features);
 617                 goto out;
 618         }
 619
 620         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
 621         if (conntrack == NULL) {
 622                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
 623                 goto out;
 624         }
 625
 626         memset(conntrack, 0, nf_ct_cache[features].size);
 627         conntrack->features = features;
 628         atomic_set(&conntrack->ct_general.use, 1);
 629         conntrack->ct_general.destroy = destroy_conntrack;
 630         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 631         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 632         /* Don't set timer yet: wait for confirmation */
 633         init_timer(&conntrack->timeout);
 634         conntrack->timeout.data = (unsigned long)conntrack;
 635         conntrack->timeout.function = death_by_timeout;
 636         read_unlock_bh(&nf_ct_cache_lock);
 637
 638         return conntrack;
 639 out:
 640         read_unlock_bh(&nf_ct_cache_lock);
 641         atomic_dec(&nf_conntrack_count);
 642         return conntrack;
 643 }
 644
 645 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 646                                    const struct nf_conntrack_tuple *repl)
 647 {
 648         struct nf_conntrack_l3proto *l3proto;
 649
 650         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
 651         return __nf_conntrack_alloc(orig, repl, l3proto, 0);
 652 }
 653 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 654
 655 void nf_conntrack_free(struct nf_conn *conntrack)
 656 {
 657         u_int32_t features = conntrack->features;
 658         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
 659         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
 660                conntrack);
 661         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
 662         atomic_dec(&nf_conntrack_count);
 663 }
 664 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 665
 666 /* Allocate a new conntrack: we return -ENOMEM if classification
 667    failed due to stress.  Otherwise it really is unclassifiable. */
 668 static struct nf_conntrack_tuple_hash *
 669 init_conntrack(const struct nf_conntrack_tuple *tuple,
 670                struct nf_conntrack_l3proto *l3proto,
 671                struct nf_conntrack_l4proto *l4proto,
 672                struct sk_buff *skb,
 673                unsigned int dataoff)
 674 {
 675         struct nf_conn *conntrack;
 676         struct nf_conntrack_tuple repl_tuple;
 677         struct nf_conntrack_expect *exp;
 678         u_int32_t features = 0;
 679
 680         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 681                 DEBUGP("Can't invert tuple.\n");
 682                 return NULL;
 683         }
 684
 685         read_lock_bh(&nf_conntrack_lock);
 686         exp = __nf_conntrack_expect_find(tuple);
 687         if (exp && exp->helper)
 688                 features = NF_CT_F_HELP;
 689         read_unlock_bh(&nf_conntrack_lock);
 690
 691         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
 692         if (conntrack == NULL || IS_ERR(conntrack)) {
 693                 DEBUGP("Can't allocate conntrack.\n");
 694                 return (struct nf_conntrack_tuple_hash *)conntrack;
 695         }
 696
 697         if (!l4proto->new(conntrack, skb, dataoff)) {
 698                 nf_conntrack_free(conntrack);
 699                 DEBUGP("init conntrack: can't track with proto module\n");
 700                 return NULL;
 701         }
 702
 703         write_lock_bh(&nf_conntrack_lock);
 704         exp = find_expectation(tuple);
 705
 706         if (exp) {
 707                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 708                         conntrack, exp);
 709                 /* Welcome, Mr. Bond.  We've been expecting you... */
 710                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 711                 conntrack->master = exp->master;
 712                 if (exp->helper)
 713                         nfct_help(conntrack)->helper = exp->helper;
 714 #ifdef CONFIG_NF_CONNTRACK_MARK
 715                 conntrack->mark = exp->master->mark;
 716 #endif
 717 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 718                 conntrack->secmark = exp->master->secmark;
 719 #endif
 720                 nf_conntrack_get(&conntrack->master->ct_general);
 721                 NF_CT_STAT_INC(expect_new);
 722         } else {
 723                 struct nf_conn_help *help = nfct_help(conntrack);
 724
 725                 if (help)
 726                         help->helper = __nf_ct_helper_find(&repl_tuple);
 727                 NF_CT_STAT_INC(new);
 728         }
 729
 730         /* Overload tuple linked list to put us in unconfirmed list. */
 731         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 732
 733         write_unlock_bh(&nf_conntrack_lock);
 734
 735         if (exp) {
 736                 if (exp->expectfn)
 737                         exp->expectfn(conntrack, exp);
 738                 nf_conntrack_expect_put(exp);
 739         }
 740
 741         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 742 }
 743
 744 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 745 static inline struct nf_conn *
 746 resolve_normal_ct(struct sk_buff *skb,
 747                   unsigned int dataoff,
 748                   u_int16_t l3num,
 749                   u_int8_t protonum,
 750                   struct nf_conntrack_l3proto *l3proto,
 751                   struct nf_conntrack_l4proto *l4proto,
 752                   int *set_reply,
 753                   enum ip_conntrack_info *ctinfo)
 754 {
 755         struct nf_conntrack_tuple tuple;
 756         struct nf_conntrack_tuple_hash *h;
 757         struct nf_conn *ct;
 758
 759         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
 760                              dataoff, l3num, protonum, &tuple, l3proto,
 761                              l4proto)) {
 762                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
 763                 return NULL;
 764         }
 765
 766         /* look for tuple match */
 767         h = nf_conntrack_find_get(&tuple, NULL);
 768         if (!h) {
 769                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 770                 if (!h)
 771                         return NULL;
 772                 if (IS_ERR(h))
 773                         return (void *)h;
 774         }
 775         ct = nf_ct_tuplehash_to_ctrack(h);
 776
 777         /* It exists; we have (non-exclusive) reference. */
 778         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 779                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 780                 /* Please set reply bit if this packet OK */
 781                 *set_reply = 1;
 782         } else {
 783                 /* Once we've had two way comms, always ESTABLISHED. */
 784                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 785                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
 786                         *ctinfo = IP_CT_ESTABLISHED;
 787                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 788                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
 789                         *ctinfo = IP_CT_RELATED;
 790                 } else {
 791                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
 792                         *ctinfo = IP_CT_NEW;
 793                 }
 794                 *set_reply = 0;
 795         }
 796         skb->nfct = &ct->ct_general;
 797         skb->nfctinfo = *ctinfo;
 798         return ct;
 799 }
 800
 801 unsigned int
 802 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 803 {
 804         struct nf_conn *ct;
 805         enum ip_conntrack_info ctinfo;
 806         struct nf_conntrack_l3proto *l3proto;
 807         struct nf_conntrack_l4proto *l4proto;
 808         unsigned int dataoff;
 809         u_int8_t protonum;
 810         int set_reply = 0;
 811         int ret;
 812
 813         /* Previously seen (loopback or untracked)?  Ignore. */
 814         if ((*pskb)->nfct) {
 815                 NF_CT_STAT_INC(ignore);
 816                 return NF_ACCEPT;
 817         }
 818
 819         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 820         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
 821                 DEBUGP("not prepared to track yet or error occured\n");
 822                 return -ret;
 823         }
 824
 825         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
 826
 827         /* It may be an special packet, error, unclean...
 828          * inverse of the return code tells to the netfilter
 829          * core what to do with the packet. */
 830         if (l4proto->error != NULL &&
 831             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 832                 NF_CT_STAT_INC(error);
 833                 NF_CT_STAT_INC(invalid);
 834                 return -ret;
 835         }
 836
 837         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
 838                                &set_reply, &ctinfo);
 839         if (!ct) {
 840                 /* Not valid part of a connection */
 841                 NF_CT_STAT_INC(invalid);
 842                 return NF_ACCEPT;
 843         }
 844
 845         if (IS_ERR(ct)) {
 846                 /* Too stressed to deal. */
 847                 NF_CT_STAT_INC(drop);
 848                 return NF_DROP;
 849         }
 850
 851         NF_CT_ASSERT((*pskb)->nfct);
 852
 853         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
 854         if (ret < 0) {
 855                 /* Invalid: inverse of the return code tells
 856                  * the netfilter core what to do */
 857                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
 858                 nf_conntrack_put((*pskb)->nfct);
 859                 (*pskb)->nfct = NULL;
 860                 NF_CT_STAT_INC(invalid);
 861                 return -ret;
 862         }
 863
 864         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 865                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
 866
 867         return ret;
 868 }
 869 EXPORT_SYMBOL_GPL(nf_conntrack_in);
 870
 871 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 872                          const struct nf_conntrack_tuple *orig)
 873 {
 874         return nf_ct_invert_tuple(inverse, orig,
 875                                   __nf_ct_l3proto_find(orig->src.l3num),
 876                                   __nf_ct_l4proto_find(orig->src.l3num,
 877                                                      orig->dst.protonum));
 878 }
 879 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 880
 881 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 882    implicitly racy: see __nf_conntrack_confirm */
 883 void nf_conntrack_alter_reply(struct nf_conn *ct,
 884                               const struct nf_conntrack_tuple *newreply)
 885 {
 886         struct nf_conn_help *help = nfct_help(ct);
 887
 888         write_lock_bh(&nf_conntrack_lock);
 889         /* Should be unconfirmed, so not in hash table yet */
 890         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 891
 892         DEBUGP("Altering reply tuple of %p to ", ct);
 893         NF_CT_DUMP_TUPLE(newreply);
 894
 895         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 896         if (!ct->master && help && help->expecting == 0)
 897                 help->helper = __nf_ct_helper_find(newreply);
 898         write_unlock_bh(&nf_conntrack_lock);
 899 }
 900 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 901
 902 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 903 void __nf_ct_refresh_acct(struct nf_conn *ct,
 904                           enum ip_conntrack_info ctinfo,
 905                           const struct sk_buff *skb,
 906                           unsigned long extra_jiffies,
 907                           int do_acct)
 908 {
 909         int event = 0;
 910
 911         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 912         NF_CT_ASSERT(skb);
 913
 914         write_lock_bh(&nf_conntrack_lock);
 915
 916         /* Only update if this is not a fixed timeout */
 917         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 918                 write_unlock_bh(&nf_conntrack_lock);
 919                 return;
 920         }
 921
 922         /* If not in hash table, timer will not be active yet */
 923         if (!nf_ct_is_confirmed(ct)) {
 924                 ct->timeout.expires = extra_jiffies;
 925                 event = IPCT_REFRESH;
 926         } else {
 927                 unsigned long newtime = jiffies + extra_jiffies;
 928
 929                 /* Only update the timeout if the new timeout is at least
 930                    HZ jiffies from the old timeout. Need del_timer for race
 931                    avoidance (may already be dying). */
 932                 if (newtime - ct->timeout.expires >= HZ
 933                     && del_timer(&ct->timeout)) {
 934                         ct->timeout.expires = newtime;
 935                         add_timer(&ct->timeout);
 936                         event = IPCT_REFRESH;
 937                 }
 938         }
 939
 940 #ifdef CONFIG_NF_CT_ACCT
 941         if (do_acct) {
 942                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 943                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 944                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
 945
 946                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 947                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 948                         event |= IPCT_COUNTER_FILLING;
 949         }
 950 #endif
 951
 952         write_unlock_bh(&nf_conntrack_lock);
 953
 954         /* must be unlocked when calling event cache */
 955         if (event)
 956                 nf_conntrack_event_cache(event, skb);
 957 }
 958 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 959
 960 #if defined(CONFIG_NF_CT_NETLINK) || \
 961     defined(CONFIG_NF_CT_NETLINK_MODULE)
 962
 963 #include <linux/netfilter/nfnetlink.h>
 964 #include <linux/netfilter/nfnetlink_conntrack.h>
 965 #include <linux/mutex.h>
 966
 967
 968 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 969  * in ip_conntrack_core, since we don't want the protocols to autoload
 970  * or depend on ctnetlink */
 971 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
 972                                const struct nf_conntrack_tuple *tuple)
 973 {
 974         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
 975                 &tuple->src.u.tcp.port);
 976         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
 977                 &tuple->dst.u.tcp.port);
 978         return 0;
 979
 980 nfattr_failure:
 981         return -1;
 982 }
 983 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
 984
 985 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
 986         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
 987         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
 988 };
 989
 990 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
 991                                struct nf_conntrack_tuple *t)
 992 {
 993         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
 994                 return -EINVAL;
 995
 996         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
 997                 return -EINVAL;
 998
 999         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1000         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1001
1002         return 0;
1003 }
1004 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1005 #endif
1006
1007 /* Used by ipt_REJECT and ip6t_REJECT. */
1008 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1009 {
1010         struct nf_conn *ct;
1011         enum ip_conntrack_info ctinfo;
1012
1013         /* This ICMP is in reverse direction to the packet which caused it */
1014         ct = nf_ct_get(skb, &ctinfo);
1015         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1016                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1017         else
1018                 ctinfo = IP_CT_RELATED;
1019
1020         /* Attach to new skbuff, and increment count */
1021         nskb->nfct = &ct->ct_general;
1022         nskb->nfctinfo = ctinfo;
1023         nf_conntrack_get(nskb->nfct);
1024 }
1025 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1026
1027 static inline int
1028 do_iter(const struct nf_conntrack_tuple_hash *i,
1029         int (*iter)(struct nf_conn *i, void *data),
1030         void *data)
1031 {
1032         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1033 }
1034
1035 /* Bring out ya dead! */
1036 static struct nf_conn *
1037 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1038                 void *data, unsigned int *bucket)
1039 {
1040         struct nf_conntrack_tuple_hash *h;
1041         struct nf_conn *ct;
1042
1043         write_lock_bh(&nf_conntrack_lock);
1044         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1045                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1046                         ct = nf_ct_tuplehash_to_ctrack(h);
1047                         if (iter(ct, data))
1048                                 goto found;
1049                 }
1050         }
1051         list_for_each_entry(h, &unconfirmed, list) {
1052                 ct = nf_ct_tuplehash_to_ctrack(h);
1053                 if (iter(ct, data))
1054                         goto found;
1055         }
1056         write_unlock_bh(&nf_conntrack_lock);
1057         return NULL;
1058 found:
1059         atomic_inc(&ct->ct_general.use);
1060         write_unlock_bh(&nf_conntrack_lock);
1061         return ct;
1062 }
1063
1064 void
1065 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1066 {
1067         struct nf_conn *ct;
1068         unsigned int bucket = 0;
1069
1070         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1071                 /* Time to push up daises... */
1072                 if (del_timer(&ct->timeout))
1073                         death_by_timeout((unsigned long)ct);
1074                 /* ... else the timer will get him soon. */
1075
1076                 nf_ct_put(ct);
1077         }
1078 }
1079 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1080
1081 static int kill_all(struct nf_conn *i, void *data)
1082 {
1083         return 1;
1084 }
1085
1086 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1087 {
1088         if (vmalloced)
1089                 vfree(hash);
1090         else
1091                 free_pages((unsigned long)hash,
1092                            get_order(sizeof(struct list_head) * size));
1093 }
1094
1095 void nf_conntrack_flush()
1096 {
1097         nf_ct_iterate_cleanup(kill_all, NULL);
1098 }
1099 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1100
1101 /* Mishearing the voices in his head, our hero wonders how he's
1102    supposed to kill the mall. */
1103 void nf_conntrack_cleanup(void)
1104 {
1105         int i;
1106
1107         ip_ct_attach = NULL;
1108
1109         /* This makes sure all current packets have passed through
1110            netfilter framework.  Roll on, two-stage module
1111            delete... */
1112         synchronize_net();
1113
1114         nf_ct_event_cache_flush();
1115  i_see_dead_people:
1116         nf_conntrack_flush();
1117         if (atomic_read(&nf_conntrack_count) != 0) {
1118                 schedule();
1119                 goto i_see_dead_people;
1120         }
1121         /* wait until all references to nf_conntrack_untracked are dropped */
1122         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1123                 schedule();
1124
1125         for (i = 0; i < NF_CT_F_NUM; i++) {
1126                 if (nf_ct_cache[i].use == 0)
1127                         continue;
1128
1129                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1130                 nf_ct_cache[i].use = 1;
1131                 nf_conntrack_unregister_cache(i);
1132         }
1133         kmem_cache_destroy(nf_conntrack_expect_cachep);
1134         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1135                             nf_conntrack_htable_size);
1136
1137         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1138
1139         /* free l3proto protocol tables */
1140         for (i = 0; i < PF_MAX; i++)
1141                 if (nf_ct_protos[i]) {
1142                         kfree(nf_ct_protos[i]);
1143                         nf_ct_protos[i] = NULL;
1144                 }
1145 }
1146
1147 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1148 {
1149         struct list_head *hash;
1150         unsigned int i;
1151
1152         *vmalloced = 0;
1153         hash = (void*)__get_free_pages(GFP_KERNEL,
1154                                        get_order(sizeof(struct list_head)
1155                                                  * size));
1156         if (!hash) {
1157                 *vmalloced = 1;
1158                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1159                 hash = vmalloc(sizeof(struct list_head) * size);
1160         }
1161
1162         if (hash)
1163                 for (i = 0; i < size; i++)
1164                         INIT_LIST_HEAD(&hash[i]);
1165
1166         return hash;
1167 }
1168
1169 int set_hashsize(const char *val, struct kernel_param *kp)
1170 {
1171         int i, bucket, hashsize, vmalloced;
1172         int old_vmalloced, old_size;
1173         int rnd;
1174         struct list_head *hash, *old_hash;
1175         struct nf_conntrack_tuple_hash *h;
1176
1177         /* On boot, we can set this without any fancy locking. */
1178         if (!nf_conntrack_htable_size)
1179                 return param_set_uint(val, kp);
1180
1181         hashsize = simple_strtol(val, NULL, 0);
1182         if (!hashsize)
1183                 return -EINVAL;
1184
1185         hash = alloc_hashtable(hashsize, &vmalloced);
1186         if (!hash)
1187                 return -ENOMEM;
1188
1189         /* We have to rehahs for the new table anyway, so we also can
1190          * use a newrandom seed */
1191         get_random_bytes(&rnd, 4);
1192
1193         write_lock_bh(&nf_conntrack_lock);
1194         for (i = 0; i < nf_conntrack_htable_size; i++) {
1195                 while (!list_empty(&nf_conntrack_hash[i])) {
1196                         h = list_entry(nf_conntrack_hash[i].next,
1197                                        struct nf_conntrack_tuple_hash, list);
1198                         list_del(&h->list);
1199                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1200                         list_add_tail(&h->list, &hash[bucket]);
1201                 }
1202         }
1203         old_size = nf_conntrack_htable_size;
1204         old_vmalloced = nf_conntrack_vmalloc;
1205         old_hash = nf_conntrack_hash;
1206
1207         nf_conntrack_htable_size = hashsize;
1208         nf_conntrack_vmalloc = vmalloced;
1209         nf_conntrack_hash = hash;
1210         nf_conntrack_hash_rnd = rnd;
1211         write_unlock_bh(&nf_conntrack_lock);
1212
1213         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1214         return 0;
1215 }
1216
1217 module_param_call(hashsize, set_hashsize, param_get_uint,
1218                   &nf_conntrack_htable_size, 0600);
1219
1220 int __init nf_conntrack_init(void)
1221 {
1222         unsigned int i;
1223         int ret;
1224
1225         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1226          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1227         if (!nf_conntrack_htable_size) {
1228                 nf_conntrack_htable_size
1229                         = (((num_physpages << PAGE_SHIFT) / 16384)
1230                            / sizeof(struct list_head));
1231                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1232                         nf_conntrack_htable_size = 8192;
1233                 if (nf_conntrack_htable_size < 16)
1234                         nf_conntrack_htable_size = 16;
1235         }
1236         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1237
1238         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1239                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1240                nf_conntrack_max);
1241
1242         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1243                                             &nf_conntrack_vmalloc);
1244         if (!nf_conntrack_hash) {
1245                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1246                 goto err_out;
1247         }
1248
1249         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1250                                           sizeof(struct nf_conn));
1251         if (ret < 0) {
1252                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1253                 goto err_free_hash;
1254         }
1255
1256         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1257                                         sizeof(struct nf_conntrack_expect),
1258                                         0, 0, NULL, NULL);
1259         if (!nf_conntrack_expect_cachep) {
1260                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1261                 goto err_free_conntrack_slab;
1262         }
1263
1264         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1265         if (ret < 0)
1266                 goto out_free_expect_slab;
1267
1268         /* Don't NEED lock here, but good form anyway. */
1269         write_lock_bh(&nf_conntrack_lock);
1270         for (i = 0; i < AF_MAX; i++)
1271                 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1272         write_unlock_bh(&nf_conntrack_lock);
1273
1274         /* For use by REJECT target */
1275         ip_ct_attach = __nf_conntrack_attach;
1276
1277         /* Set up fake conntrack:
1278             - to never be deleted, not in any hashes */
1279         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1280         /*  - and look it like as a confirmed connection */
1281         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1282
1283         return ret;
1284
1285 out_free_expect_slab:
1286         kmem_cache_destroy(nf_conntrack_expect_cachep);
1287 err_free_conntrack_slab:
1288         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1289 err_free_hash:
1290         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1291                             nf_conntrack_htable_size);
1292 err_out:
1293         return -ENOMEM;
1294 }