net/netfilter/nf_conntrack_core.c

   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
  14 #include <linux/types.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/stddef.h>
  21 #include <linux/slab.h>
  22 #include <linux/random.h>
  23 #include <linux/jhash.h>
  24 #include <linux/err.h>
  25 #include <linux/percpu.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/notifier.h>
  28 #include <linux/kernel.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/socket.h>
  31 #include <linux/mm.h>
  32
  33 #include <net/netfilter/nf_conntrack.h>
  34 #include <net/netfilter/nf_conntrack_l3proto.h>
  35 #include <net/netfilter/nf_conntrack_l4proto.h>
  36 #include <net/netfilter/nf_conntrack_expect.h>
  37 #include <net/netfilter/nf_conntrack_helper.h>
  38 #include <net/netfilter/nf_conntrack_core.h>
  39 #include <net/netfilter/nf_conntrack_extend.h>
  40
  41 #define NF_CONNTRACK_VERSION    "0.5.0"
  42
  43 #if 0
  44 #define DEBUGP printk
  45 #else
  46 #define DEBUGP(format, args...)
  47 #endif
  48
  49 DEFINE_RWLOCK(nf_conntrack_lock);
  50 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  51
  52 /* nf_conntrack_standalone needs this */
  53 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  54 EXPORT_SYMBOL_GPL(nf_conntrack_count);
  55
  56 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
  57 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed);
  58
  59 unsigned int nf_conntrack_htable_size __read_mostly;
  60 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  61
  62 int nf_conntrack_max __read_mostly;
  63 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  64
  65 struct list_head *nf_conntrack_hash __read_mostly;
  66 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  67
  68 struct nf_conn nf_conntrack_untracked __read_mostly;
  69 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
  70
  71 unsigned int nf_ct_log_invalid __read_mostly;
  72 LIST_HEAD(unconfirmed);
  73 static int nf_conntrack_vmalloc __read_mostly;
  74
  75 static unsigned int nf_conntrack_next_id;
  76
  77 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  78 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  79
  80 /*
  81  * This scheme offers various size of "struct nf_conn" dependent on
  82  * features(helper, nat, ...)
  83  */
  84
  85 #define NF_CT_FEATURES_NAMELEN  256
  86 static struct {
  87         /* name of slab cache. printed in /proc/slabinfo */
  88         char *name;
  89
  90         /* size of slab cache */
  91         size_t size;
  92
  93         /* slab cache pointer */
  94         struct kmem_cache *cachep;
  95
  96         /* allocated slab cache + modules which uses this slab cache */
  97         int use;
  98
  99 } nf_ct_cache[NF_CT_F_NUM];
 100
 101 /* protect members of nf_ct_cache except of "use" */
 102 DEFINE_RWLOCK(nf_ct_cache_lock);
 103
 104 /* This avoids calling kmem_cache_create() with same name simultaneously */
 105 static DEFINE_MUTEX(nf_ct_cache_mutex);
 106
 107 static int nf_conntrack_hash_rnd_initted;
 108 static unsigned int nf_conntrack_hash_rnd;
 109
 110 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 111                                   unsigned int size, unsigned int rnd)
 112 {
 113         unsigned int a, b;
 114
 115         a = jhash2(tuple->src.u3.all, ARRAY_SIZE(tuple->src.u3.all),
 116                    (tuple->src.l3num << 16) | tuple->dst.protonum);
 117         b = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
 118                    (tuple->src.u.all << 16) | tuple->dst.u.all);
 119
 120         return jhash_2words(a, b, rnd) % size;
 121 }
 122
 123 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
 124 {
 125         return __hash_conntrack(tuple, nf_conntrack_htable_size,
 126                                 nf_conntrack_hash_rnd);
 127 }
 128
 129 int nf_conntrack_register_cache(u_int32_t features, const char *name,
 130                                 size_t size)
 131 {
 132         int ret = 0;
 133         char *cache_name;
 134         struct kmem_cache *cachep;
 135
 136         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
 137                features, name, size);
 138
 139         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
 140                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
 141                         features);
 142                 return -EINVAL;
 143         }
 144
 145         mutex_lock(&nf_ct_cache_mutex);
 146
 147         write_lock_bh(&nf_ct_cache_lock);
 148         /* e.g: multiple helpers are loaded */
 149         if (nf_ct_cache[features].use > 0) {
 150                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
 151                 if ((!strncmp(nf_ct_cache[features].name, name,
 152                               NF_CT_FEATURES_NAMELEN))
 153                     && nf_ct_cache[features].size == size) {
 154                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
 155                         nf_ct_cache[features].use++;
 156                         ret = 0;
 157                 } else
 158                         ret = -EBUSY;
 159
 160                 write_unlock_bh(&nf_ct_cache_lock);
 161                 mutex_unlock(&nf_ct_cache_mutex);
 162                 return ret;
 163         }
 164         write_unlock_bh(&nf_ct_cache_lock);
 165
 166         /*
 167          * The memory space for name of slab cache must be alive until
 168          * cache is destroyed.
 169          */
 170         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
 171         if (cache_name == NULL) {
 172                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
 173                 ret = -ENOMEM;
 174                 goto out_up_mutex;
 175         }
 176
 177         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
 178                                                 >= NF_CT_FEATURES_NAMELEN) {
 179                 printk("nf_conntrack_register_cache: name too long\n");
 180                 ret = -EINVAL;
 181                 goto out_free_name;
 182         }
 183
 184         cachep = kmem_cache_create(cache_name, size, 0, 0,
 185                                    NULL, NULL);
 186         if (!cachep) {
 187                 printk("nf_conntrack_register_cache: Can't create slab cache "
 188                        "for the features = 0x%x\n", features);
 189                 ret = -ENOMEM;
 190                 goto out_free_name;
 191         }
 192
 193         write_lock_bh(&nf_ct_cache_lock);
 194         nf_ct_cache[features].use = 1;
 195         nf_ct_cache[features].size = size;
 196         nf_ct_cache[features].cachep = cachep;
 197         nf_ct_cache[features].name = cache_name;
 198         write_unlock_bh(&nf_ct_cache_lock);
 199
 200         goto out_up_mutex;
 201
 202 out_free_name:
 203         kfree(cache_name);
 204 out_up_mutex:
 205         mutex_unlock(&nf_ct_cache_mutex);
 206         return ret;
 207 }
 208 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache);
 209
 210 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
 211 void nf_conntrack_unregister_cache(u_int32_t features)
 212 {
 213         struct kmem_cache *cachep;
 214         char *name;
 215
 216         /*
 217          * This assures that kmem_cache_create() isn't called before destroying
 218          * slab cache.
 219          */
 220         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
 221         mutex_lock(&nf_ct_cache_mutex);
 222
 223         write_lock_bh(&nf_ct_cache_lock);
 224         if (--nf_ct_cache[features].use > 0) {
 225                 write_unlock_bh(&nf_ct_cache_lock);
 226                 mutex_unlock(&nf_ct_cache_mutex);
 227                 return;
 228         }
 229         cachep = nf_ct_cache[features].cachep;
 230         name = nf_ct_cache[features].name;
 231         nf_ct_cache[features].cachep = NULL;
 232         nf_ct_cache[features].name = NULL;
 233         nf_ct_cache[features].size = 0;
 234         write_unlock_bh(&nf_ct_cache_lock);
 235
 236         synchronize_net();
 237
 238         kmem_cache_destroy(cachep);
 239         kfree(name);
 240
 241         mutex_unlock(&nf_ct_cache_mutex);
 242 }
 243 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache);
 244
 245 int
 246 nf_ct_get_tuple(const struct sk_buff *skb,
 247                 unsigned int nhoff,
 248                 unsigned int dataoff,
 249                 u_int16_t l3num,
 250                 u_int8_t protonum,
 251                 struct nf_conntrack_tuple *tuple,
 252                 const struct nf_conntrack_l3proto *l3proto,
 253                 const struct nf_conntrack_l4proto *l4proto)
 254 {
 255         NF_CT_TUPLE_U_BLANK(tuple);
 256
 257         tuple->src.l3num = l3num;
 258         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 259                 return 0;
 260
 261         tuple->dst.protonum = protonum;
 262         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 263
 264         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 265 }
 266 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 267
 268 int
 269 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 270                    const struct nf_conntrack_tuple *orig,
 271                    const struct nf_conntrack_l3proto *l3proto,
 272                    const struct nf_conntrack_l4proto *l4proto)
 273 {
 274         NF_CT_TUPLE_U_BLANK(inverse);
 275
 276         inverse->src.l3num = orig->src.l3num;
 277         if (l3proto->invert_tuple(inverse, orig) == 0)
 278                 return 0;
 279
 280         inverse->dst.dir = !orig->dst.dir;
 281
 282         inverse->dst.protonum = orig->dst.protonum;
 283         return l4proto->invert_tuple(inverse, orig);
 284 }
 285 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 286
 287 static void
 288 clean_from_lists(struct nf_conn *ct)
 289 {
 290         DEBUGP("clean_from_lists(%p)\n", ct);
 291         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 292         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
 293
 294         /* Destroy all pending expectations */
 295         nf_ct_remove_expectations(ct);
 296 }
 297
 298 static void
 299 destroy_conntrack(struct nf_conntrack *nfct)
 300 {
 301         struct nf_conn *ct = (struct nf_conn *)nfct;
 302         struct nf_conntrack_l4proto *l4proto;
 303         typeof(nf_conntrack_destroyed) destroyed;
 304
 305         DEBUGP("destroy_conntrack(%p)\n", ct);
 306         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 307         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 308
 309         nf_conntrack_event(IPCT_DESTROY, ct);
 310         set_bit(IPS_DYING_BIT, &ct->status);
 311
 312         /* To make sure we don't get any weird locking issues here:
 313          * destroy_conntrack() MUST NOT be called with a write lock
 314          * to nf_conntrack_lock!!! -HW */
 315         rcu_read_lock();
 316         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
 317                                        ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 318         if (l4proto && l4proto->destroy)
 319                 l4proto->destroy(ct);
 320
 321         nf_ct_ext_destroy(ct);
 322
 323         destroyed = rcu_dereference(nf_conntrack_destroyed);
 324         if (destroyed)
 325                 destroyed(ct);
 326
 327         rcu_read_unlock();
 328
 329         write_lock_bh(&nf_conntrack_lock);
 330         /* Expectations will have been removed in clean_from_lists,
 331          * except TFTP can create an expectation on the first packet,
 332          * before connection is in the list, so we need to clean here,
 333          * too. */
 334         nf_ct_remove_expectations(ct);
 335
 336         /* We overload first tuple to link into unconfirmed list. */
 337         if (!nf_ct_is_confirmed(ct)) {
 338                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 339                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 340         }
 341
 342         NF_CT_STAT_INC(delete);
 343         write_unlock_bh(&nf_conntrack_lock);
 344
 345         if (ct->master)
 346                 nf_ct_put(ct->master);
 347
 348         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 349         nf_conntrack_free(ct);
 350 }
 351
 352 static void death_by_timeout(unsigned long ul_conntrack)
 353 {
 354         struct nf_conn *ct = (void *)ul_conntrack;
 355         struct nf_conn_help *help = nfct_help(ct);
 356         struct nf_conntrack_helper *helper;
 357
 358         if (help) {
 359                 rcu_read_lock();
 360                 helper = rcu_dereference(help->helper);
 361                 if (helper && helper->destroy)
 362                         helper->destroy(ct);
 363                 rcu_read_unlock();
 364         }
 365
 366         write_lock_bh(&nf_conntrack_lock);
 367         /* Inside lock so preempt is disabled on module removal path.
 368          * Otherwise we can get spurious warnings. */
 369         NF_CT_STAT_INC(delete_list);
 370         clean_from_lists(ct);
 371         write_unlock_bh(&nf_conntrack_lock);
 372         nf_ct_put(ct);
 373 }
 374
 375 struct nf_conntrack_tuple_hash *
 376 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 377                     const struct nf_conn *ignored_conntrack)
 378 {
 379         struct nf_conntrack_tuple_hash *h;
 380         unsigned int hash = hash_conntrack(tuple);
 381
 382         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
 383                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 384                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 385                         NF_CT_STAT_INC(found);
 386                         return h;
 387                 }
 388                 NF_CT_STAT_INC(searched);
 389         }
 390
 391         return NULL;
 392 }
 393 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 394
 395 /* Find a connection corresponding to a tuple. */
 396 struct nf_conntrack_tuple_hash *
 397 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
 398                       const struct nf_conn *ignored_conntrack)
 399 {
 400         struct nf_conntrack_tuple_hash *h;
 401
 402         read_lock_bh(&nf_conntrack_lock);
 403         h = __nf_conntrack_find(tuple, ignored_conntrack);
 404         if (h)
 405                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 406         read_unlock_bh(&nf_conntrack_lock);
 407
 408         return h;
 409 }
 410 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 411
 412 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 413                                        unsigned int hash,
 414                                        unsigned int repl_hash)
 415 {
 416         ct->id = ++nf_conntrack_next_id;
 417         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
 418                  &nf_conntrack_hash[hash]);
 419         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
 420                  &nf_conntrack_hash[repl_hash]);
 421 }
 422
 423 void nf_conntrack_hash_insert(struct nf_conn *ct)
 424 {
 425         unsigned int hash, repl_hash;
 426
 427         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 428         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 429
 430         write_lock_bh(&nf_conntrack_lock);
 431         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 432         write_unlock_bh(&nf_conntrack_lock);
 433 }
 434 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 435
 436 /* Confirm a connection given skb; places it in hash table */
 437 int
 438 __nf_conntrack_confirm(struct sk_buff **pskb)
 439 {
 440         unsigned int hash, repl_hash;
 441         struct nf_conntrack_tuple_hash *h;
 442         struct nf_conn *ct;
 443         struct nf_conn_help *help;
 444         enum ip_conntrack_info ctinfo;
 445
 446         ct = nf_ct_get(*pskb, &ctinfo);
 447
 448         /* ipt_REJECT uses nf_conntrack_attach to attach related
 449            ICMP/TCP RST packets in other direction.  Actual packet
 450            which created connection will be IP_CT_NEW or for an
 451            expected connection, IP_CT_RELATED. */
 452         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 453                 return NF_ACCEPT;
 454
 455         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 456         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 457
 458         /* We're not in hash table, and we refuse to set up related
 459            connections for unconfirmed conns.  But packet copies and
 460            REJECT will give spurious warnings here. */
 461         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 462
 463         /* No external references means noone else could have
 464            confirmed us. */
 465         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 466         DEBUGP("Confirming conntrack %p\n", ct);
 467
 468         write_lock_bh(&nf_conntrack_lock);
 469
 470         /* See if there's one in the list already, including reverse:
 471            NAT could have grabbed it without realizing, since we're
 472            not in the hash.  If there is, we lost race. */
 473         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
 474                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 475                                       &h->tuple))
 476                         goto out;
 477         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
 478                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 479                                       &h->tuple))
 480                         goto out;
 481
 482         /* Remove from unconfirmed list */
 483         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 484
 485         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 486         /* Timer relative to confirmation time, not original
 487            setting time, otherwise we'd get timer wrap in
 488            weird delay cases. */
 489         ct->timeout.expires += jiffies;
 490         add_timer(&ct->timeout);
 491         atomic_inc(&ct->ct_general.use);
 492         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 493         NF_CT_STAT_INC(insert);
 494         write_unlock_bh(&nf_conntrack_lock);
 495         help = nfct_help(ct);
 496         if (help && help->helper)
 497                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 498 #ifdef CONFIG_NF_NAT_NEEDED
 499         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 500             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 501                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 502 #endif
 503         nf_conntrack_event_cache(master_ct(ct) ?
 504                                  IPCT_RELATED : IPCT_NEW, *pskb);
 505         return NF_ACCEPT;
 506
 507 out:
 508         NF_CT_STAT_INC(insert_failed);
 509         write_unlock_bh(&nf_conntrack_lock);
 510         return NF_DROP;
 511 }
 512 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 513
 514 /* Returns true if a connection correspondings to the tuple (required
 515    for NAT). */
 516 int
 517 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 518                          const struct nf_conn *ignored_conntrack)
 519 {
 520         struct nf_conntrack_tuple_hash *h;
 521
 522         read_lock_bh(&nf_conntrack_lock);
 523         h = __nf_conntrack_find(tuple, ignored_conntrack);
 524         read_unlock_bh(&nf_conntrack_lock);
 525
 526         return h != NULL;
 527 }
 528 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 529
 530 /* There's a small race here where we may free a just-assured
 531    connection.  Too bad: we're in trouble anyway. */
 532 static int early_drop(struct list_head *chain)
 533 {
 534         /* Traverse backwards: gives us oldest, which is roughly LRU */
 535         struct nf_conntrack_tuple_hash *h;
 536         struct nf_conn *ct = NULL, *tmp;
 537         int dropped = 0;
 538
 539         read_lock_bh(&nf_conntrack_lock);
 540         list_for_each_entry_reverse(h, chain, list) {
 541                 tmp = nf_ct_tuplehash_to_ctrack(h);
 542                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
 543                         ct = tmp;
 544                         atomic_inc(&ct->ct_general.use);
 545                         break;
 546                 }
 547         }
 548         read_unlock_bh(&nf_conntrack_lock);
 549
 550         if (!ct)
 551                 return dropped;
 552
 553         if (del_timer(&ct->timeout)) {
 554                 death_by_timeout((unsigned long)ct);
 555                 dropped = 1;
 556                 NF_CT_STAT_INC_ATOMIC(early_drop);
 557         }
 558         nf_ct_put(ct);
 559         return dropped;
 560 }
 561
 562 static struct nf_conn *
 563 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 564                      const struct nf_conntrack_tuple *repl,
 565                      const struct nf_conntrack_l3proto *l3proto,
 566                      u_int32_t features)
 567 {
 568         struct nf_conn *conntrack = NULL;
 569
 570         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 571                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 572                 nf_conntrack_hash_rnd_initted = 1;
 573         }
 574
 575         /* We don't want any race condition at early drop stage */
 576         atomic_inc(&nf_conntrack_count);
 577
 578         if (nf_conntrack_max
 579             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 580                 unsigned int hash = hash_conntrack(orig);
 581                 /* Try dropping from this hash chain. */
 582                 if (!early_drop(&nf_conntrack_hash[hash])) {
 583                         atomic_dec(&nf_conntrack_count);
 584                         if (net_ratelimit())
 585                                 printk(KERN_WARNING
 586                                        "nf_conntrack: table full, dropping"
 587                                        " packet.\n");
 588                         return ERR_PTR(-ENOMEM);
 589                 }
 590         }
 591
 592         /*  find features needed by this conntrack. */
 593         features |= l3proto->get_features(orig);
 594
 595         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 596
 597         read_lock_bh(&nf_ct_cache_lock);
 598
 599         if (unlikely(!nf_ct_cache[features].use)) {
 600                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
 601                         features);
 602                 goto out;
 603         }
 604
 605         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
 606         if (conntrack == NULL) {
 607                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
 608                 goto out;
 609         }
 610
 611         memset(conntrack, 0, nf_ct_cache[features].size);
 612         conntrack->features = features;
 613         atomic_set(&conntrack->ct_general.use, 1);
 614         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 615         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 616         /* Don't set timer yet: wait for confirmation */
 617         setup_timer(&conntrack->timeout, death_by_timeout,
 618                     (unsigned long)conntrack);
 619         read_unlock_bh(&nf_ct_cache_lock);
 620
 621         return conntrack;
 622 out:
 623         read_unlock_bh(&nf_ct_cache_lock);
 624         atomic_dec(&nf_conntrack_count);
 625         return conntrack;
 626 }
 627
 628 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 629                                    const struct nf_conntrack_tuple *repl)
 630 {
 631         struct nf_conntrack_l3proto *l3proto;
 632         struct nf_conn *ct;
 633
 634         rcu_read_lock();
 635         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
 636         ct = __nf_conntrack_alloc(orig, repl, l3proto, 0);
 637         rcu_read_unlock();
 638
 639         return ct;
 640 }
 641 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 642
 643 void nf_conntrack_free(struct nf_conn *conntrack)
 644 {
 645         u_int32_t features = conntrack->features;
 646         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
 647         nf_ct_ext_free(conntrack);
 648         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
 649                conntrack);
 650         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
 651         atomic_dec(&nf_conntrack_count);
 652 }
 653 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 654
 655 /* Allocate a new conntrack: we return -ENOMEM if classification
 656    failed due to stress.  Otherwise it really is unclassifiable. */
 657 static struct nf_conntrack_tuple_hash *
 658 init_conntrack(const struct nf_conntrack_tuple *tuple,
 659                struct nf_conntrack_l3proto *l3proto,
 660                struct nf_conntrack_l4proto *l4proto,
 661                struct sk_buff *skb,
 662                unsigned int dataoff)
 663 {
 664         struct nf_conn *conntrack;
 665         struct nf_conn_help *help;
 666         struct nf_conntrack_tuple repl_tuple;
 667         struct nf_conntrack_expect *exp;
 668         u_int32_t features = 0;
 669
 670         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 671                 DEBUGP("Can't invert tuple.\n");
 672                 return NULL;
 673         }
 674
 675         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
 676         if (conntrack == NULL || IS_ERR(conntrack)) {
 677                 DEBUGP("Can't allocate conntrack.\n");
 678                 return (struct nf_conntrack_tuple_hash *)conntrack;
 679         }
 680
 681         if (!l4proto->new(conntrack, skb, dataoff)) {
 682                 nf_conntrack_free(conntrack);
 683                 DEBUGP("init conntrack: can't track with proto module\n");
 684                 return NULL;
 685         }
 686
 687         write_lock_bh(&nf_conntrack_lock);
 688         exp = find_expectation(tuple);
 689         if (exp) {
 690                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 691                         conntrack, exp);
 692                 /* Welcome, Mr. Bond.  We've been expecting you... */
 693                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 694                 conntrack->master = exp->master;
 695                 if (exp->helper) {
 696                         help = nf_ct_ext_add(conntrack, NF_CT_EXT_HELPER,
 697                                              GFP_ATOMIC);
 698                         if (help)
 699                                 rcu_assign_pointer(help->helper, exp->helper);
 700                         else
 701                                 DEBUGP("failed to add helper extension area");
 702                 }
 703
 704 #ifdef CONFIG_NF_CONNTRACK_MARK
 705                 conntrack->mark = exp->master->mark;
 706 #endif
 707 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 708                 conntrack->secmark = exp->master->secmark;
 709 #endif
 710                 nf_conntrack_get(&conntrack->master->ct_general);
 711                 NF_CT_STAT_INC(expect_new);
 712         } else {
 713                 struct nf_conntrack_helper *helper;
 714
 715                 helper = __nf_ct_helper_find(&repl_tuple);
 716                 if (helper) {
 717                         help = nf_ct_ext_add(conntrack, NF_CT_EXT_HELPER,
 718                                              GFP_ATOMIC);
 719                         if (help)
 720                                 /* not in hash table yet, so not strictly
 721                                    necessary */
 722                                 rcu_assign_pointer(help->helper, helper);
 723                         else
 724                                 DEBUGP("failed to add helper extension area");
 725                 }
 726                 NF_CT_STAT_INC(new);
 727         }
 728
 729         /* Overload tuple linked list to put us in unconfirmed list. */
 730         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 731
 732         write_unlock_bh(&nf_conntrack_lock);
 733
 734         if (exp) {
 735                 if (exp->expectfn)
 736                         exp->expectfn(conntrack, exp);
 737                 nf_conntrack_expect_put(exp);
 738         }
 739
 740         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 741 }
 742
 743 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 744 static inline struct nf_conn *
 745 resolve_normal_ct(struct sk_buff *skb,
 746                   unsigned int dataoff,
 747                   u_int16_t l3num,
 748                   u_int8_t protonum,
 749                   struct nf_conntrack_l3proto *l3proto,
 750                   struct nf_conntrack_l4proto *l4proto,
 751                   int *set_reply,
 752                   enum ip_conntrack_info *ctinfo)
 753 {
 754         struct nf_conntrack_tuple tuple;
 755         struct nf_conntrack_tuple_hash *h;
 756         struct nf_conn *ct;
 757
 758         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 759                              dataoff, l3num, protonum, &tuple, l3proto,
 760                              l4proto)) {
 761                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
 762                 return NULL;
 763         }
 764
 765         /* look for tuple match */
 766         h = nf_conntrack_find_get(&tuple, NULL);
 767         if (!h) {
 768                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 769                 if (!h)
 770                         return NULL;
 771                 if (IS_ERR(h))
 772                         return (void *)h;
 773         }
 774         ct = nf_ct_tuplehash_to_ctrack(h);
 775
 776         /* It exists; we have (non-exclusive) reference. */
 777         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 778                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 779                 /* Please set reply bit if this packet OK */
 780                 *set_reply = 1;
 781         } else {
 782                 /* Once we've had two way comms, always ESTABLISHED. */
 783                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 784                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
 785                         *ctinfo = IP_CT_ESTABLISHED;
 786                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 787                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
 788                         *ctinfo = IP_CT_RELATED;
 789                 } else {
 790                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
 791                         *ctinfo = IP_CT_NEW;
 792                 }
 793                 *set_reply = 0;
 794         }
 795         skb->nfct = &ct->ct_general;
 796         skb->nfctinfo = *ctinfo;
 797         return ct;
 798 }
 799
 800 unsigned int
 801 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 802 {
 803         struct nf_conn *ct;
 804         enum ip_conntrack_info ctinfo;
 805         struct nf_conntrack_l3proto *l3proto;
 806         struct nf_conntrack_l4proto *l4proto;
 807         unsigned int dataoff;
 808         u_int8_t protonum;
 809         int set_reply = 0;
 810         int ret;
 811
 812         /* Previously seen (loopback or untracked)?  Ignore. */
 813         if ((*pskb)->nfct) {
 814                 NF_CT_STAT_INC_ATOMIC(ignore);
 815                 return NF_ACCEPT;
 816         }
 817
 818         /* rcu_read_lock()ed by nf_hook_slow */
 819         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 820
 821         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
 822                 DEBUGP("not prepared to track yet or error occured\n");
 823                 return -ret;
 824         }
 825
 826         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
 827
 828         /* It may be an special packet, error, unclean...
 829          * inverse of the return code tells to the netfilter
 830          * core what to do with the packet. */
 831         if (l4proto->error != NULL &&
 832             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 833                 NF_CT_STAT_INC_ATOMIC(error);
 834                 NF_CT_STAT_INC_ATOMIC(invalid);
 835                 return -ret;
 836         }
 837
 838         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
 839                                &set_reply, &ctinfo);
 840         if (!ct) {
 841                 /* Not valid part of a connection */
 842                 NF_CT_STAT_INC_ATOMIC(invalid);
 843                 return NF_ACCEPT;
 844         }
 845
 846         if (IS_ERR(ct)) {
 847                 /* Too stressed to deal. */
 848                 NF_CT_STAT_INC_ATOMIC(drop);
 849                 return NF_DROP;
 850         }
 851
 852         NF_CT_ASSERT((*pskb)->nfct);
 853
 854         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
 855         if (ret < 0) {
 856                 /* Invalid: inverse of the return code tells
 857                  * the netfilter core what to do */
 858                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
 859                 nf_conntrack_put((*pskb)->nfct);
 860                 (*pskb)->nfct = NULL;
 861                 NF_CT_STAT_INC_ATOMIC(invalid);
 862                 return -ret;
 863         }
 864
 865         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 866                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
 867
 868         return ret;
 869 }
 870 EXPORT_SYMBOL_GPL(nf_conntrack_in);
 871
 872 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 873                          const struct nf_conntrack_tuple *orig)
 874 {
 875         int ret;
 876
 877         rcu_read_lock();
 878         ret = nf_ct_invert_tuple(inverse, orig,
 879                                  __nf_ct_l3proto_find(orig->src.l3num),
 880                                  __nf_ct_l4proto_find(orig->src.l3num,
 881                                                       orig->dst.protonum));
 882         rcu_read_unlock();
 883         return ret;
 884 }
 885 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 886
 887 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 888    implicitly racy: see __nf_conntrack_confirm */
 889 void nf_conntrack_alter_reply(struct nf_conn *ct,
 890                               const struct nf_conntrack_tuple *newreply)
 891 {
 892         struct nf_conn_help *help = nfct_help(ct);
 893         struct nf_conntrack_helper *helper;
 894
 895         write_lock_bh(&nf_conntrack_lock);
 896         /* Should be unconfirmed, so not in hash table yet */
 897         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 898
 899         DEBUGP("Altering reply tuple of %p to ", ct);
 900         NF_CT_DUMP_TUPLE(newreply);
 901
 902         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 903         if (ct->master || (help && help->expecting != 0))
 904                 goto out;
 905
 906         helper = __nf_ct_helper_find(newreply);
 907         if (helper == NULL) {
 908                 if (help)
 909                         rcu_assign_pointer(help->helper, NULL);
 910                 goto out;
 911         }
 912
 913         if (help == NULL) {
 914                 help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, GFP_ATOMIC);
 915                 if (help == NULL) {
 916                         DEBUGP("failed to add helper extension area");
 917                         goto out;
 918                 }
 919         } else {
 920                 memset(&help->help, 0, sizeof(help->help));
 921         }
 922
 923         rcu_assign_pointer(help->helper, helper);
 924 out:
 925         write_unlock_bh(&nf_conntrack_lock);
 926 }
 927 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 928
 929 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 930 void __nf_ct_refresh_acct(struct nf_conn *ct,
 931                           enum ip_conntrack_info ctinfo,
 932                           const struct sk_buff *skb,
 933                           unsigned long extra_jiffies,
 934                           int do_acct)
 935 {
 936         int event = 0;
 937
 938         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 939         NF_CT_ASSERT(skb);
 940
 941         write_lock_bh(&nf_conntrack_lock);
 942
 943         /* Only update if this is not a fixed timeout */
 944         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 945                 write_unlock_bh(&nf_conntrack_lock);
 946                 return;
 947         }
 948
 949         /* If not in hash table, timer will not be active yet */
 950         if (!nf_ct_is_confirmed(ct)) {
 951                 ct->timeout.expires = extra_jiffies;
 952                 event = IPCT_REFRESH;
 953         } else {
 954                 unsigned long newtime = jiffies + extra_jiffies;
 955
 956                 /* Only update the timeout if the new timeout is at least
 957                    HZ jiffies from the old timeout. Need del_timer for race
 958                    avoidance (may already be dying). */
 959                 if (newtime - ct->timeout.expires >= HZ
 960                     && del_timer(&ct->timeout)) {
 961                         ct->timeout.expires = newtime;
 962                         add_timer(&ct->timeout);
 963                         event = IPCT_REFRESH;
 964                 }
 965         }
 966
 967 #ifdef CONFIG_NF_CT_ACCT
 968         if (do_acct) {
 969                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 970                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 971                         skb->len - skb_network_offset(skb);
 972
 973                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 974                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 975                         event |= IPCT_COUNTER_FILLING;
 976         }
 977 #endif
 978
 979         write_unlock_bh(&nf_conntrack_lock);
 980
 981         /* must be unlocked when calling event cache */
 982         if (event)
 983                 nf_conntrack_event_cache(event, skb);
 984 }
 985 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 986
 987 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 988
 989 #include <linux/netfilter/nfnetlink.h>
 990 #include <linux/netfilter/nfnetlink_conntrack.h>
 991 #include <linux/mutex.h>
 992
 993
 994 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 995  * in ip_conntrack_core, since we don't want the protocols to autoload
 996  * or depend on ctnetlink */
 997 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
 998                                const struct nf_conntrack_tuple *tuple)
 999 {
1000         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
1001                 &tuple->src.u.tcp.port);
1002         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
1003                 &tuple->dst.u.tcp.port);
1004         return 0;
1005
1006 nfattr_failure:
1007         return -1;
1008 }
1009 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
1010
1011 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
1012         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
1013         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
1014 };
1015
1016 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
1017                                struct nf_conntrack_tuple *t)
1018 {
1019         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
1020                 return -EINVAL;
1021
1022         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
1023                 return -EINVAL;
1024
1025         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1026         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1027
1028         return 0;
1029 }
1030 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1031 #endif
1032
1033 /* Used by ipt_REJECT and ip6t_REJECT. */
1034 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1035 {
1036         struct nf_conn *ct;
1037         enum ip_conntrack_info ctinfo;
1038
1039         /* This ICMP is in reverse direction to the packet which caused it */
1040         ct = nf_ct_get(skb, &ctinfo);
1041         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1042                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1043         else
1044                 ctinfo = IP_CT_RELATED;
1045
1046         /* Attach to new skbuff, and increment count */
1047         nskb->nfct = &ct->ct_general;
1048         nskb->nfctinfo = ctinfo;
1049         nf_conntrack_get(nskb->nfct);
1050 }
1051 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1052
1053 static inline int
1054 do_iter(const struct nf_conntrack_tuple_hash *i,
1055         int (*iter)(struct nf_conn *i, void *data),
1056         void *data)
1057 {
1058         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1059 }
1060
1061 /* Bring out ya dead! */
1062 static struct nf_conn *
1063 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1064                 void *data, unsigned int *bucket)
1065 {
1066         struct nf_conntrack_tuple_hash *h;
1067         struct nf_conn *ct;
1068
1069         write_lock_bh(&nf_conntrack_lock);
1070         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1071                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1072                         ct = nf_ct_tuplehash_to_ctrack(h);
1073                         if (iter(ct, data))
1074                                 goto found;
1075                 }
1076         }
1077         list_for_each_entry(h, &unconfirmed, list) {
1078                 ct = nf_ct_tuplehash_to_ctrack(h);
1079                 if (iter(ct, data))
1080                         set_bit(IPS_DYING_BIT, &ct->status);
1081         }
1082         write_unlock_bh(&nf_conntrack_lock);
1083         return NULL;
1084 found:
1085         atomic_inc(&ct->ct_general.use);
1086         write_unlock_bh(&nf_conntrack_lock);
1087         return ct;
1088 }
1089
1090 void
1091 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1092 {
1093         struct nf_conn *ct;
1094         unsigned int bucket = 0;
1095
1096         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1097                 /* Time to push up daises... */
1098                 if (del_timer(&ct->timeout))
1099                         death_by_timeout((unsigned long)ct);
1100                 /* ... else the timer will get him soon. */
1101
1102                 nf_ct_put(ct);
1103         }
1104 }
1105 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1106
1107 static int kill_all(struct nf_conn *i, void *data)
1108 {
1109         return 1;
1110 }
1111
1112 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1113 {
1114         if (vmalloced)
1115                 vfree(hash);
1116         else
1117                 free_pages((unsigned long)hash,
1118                            get_order(sizeof(struct list_head) * size));
1119 }
1120
1121 void nf_conntrack_flush(void)
1122 {
1123         nf_ct_iterate_cleanup(kill_all, NULL);
1124 }
1125 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1126
1127 /* Mishearing the voices in his head, our hero wonders how he's
1128    supposed to kill the mall. */
1129 void nf_conntrack_cleanup(void)
1130 {
1131         int i;
1132
1133         rcu_assign_pointer(ip_ct_attach, NULL);
1134
1135         /* This makes sure all current packets have passed through
1136            netfilter framework.  Roll on, two-stage module
1137            delete... */
1138         synchronize_net();
1139
1140         nf_ct_event_cache_flush();
1141  i_see_dead_people:
1142         nf_conntrack_flush();
1143         if (atomic_read(&nf_conntrack_count) != 0) {
1144                 schedule();
1145                 goto i_see_dead_people;
1146         }
1147         /* wait until all references to nf_conntrack_untracked are dropped */
1148         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1149                 schedule();
1150
1151         rcu_assign_pointer(nf_ct_destroy, NULL);
1152
1153         for (i = 0; i < NF_CT_F_NUM; i++) {
1154                 if (nf_ct_cache[i].use == 0)
1155                         continue;
1156
1157                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1158                 nf_ct_cache[i].use = 1;
1159                 nf_conntrack_unregister_cache(i);
1160         }
1161         kmem_cache_destroy(nf_conntrack_expect_cachep);
1162         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1163                             nf_conntrack_htable_size);
1164
1165         nf_conntrack_proto_fini();
1166         nf_conntrack_helper_fini();
1167 }
1168
1169 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1170 {
1171         struct list_head *hash;
1172         unsigned int i;
1173
1174         *vmalloced = 0;
1175         hash = (void*)__get_free_pages(GFP_KERNEL,
1176                                        get_order(sizeof(struct list_head)
1177                                                  * size));
1178         if (!hash) {
1179                 *vmalloced = 1;
1180                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1181                 hash = vmalloc(sizeof(struct list_head) * size);
1182         }
1183
1184         if (hash)
1185                 for (i = 0; i < size; i++)
1186                         INIT_LIST_HEAD(&hash[i]);
1187
1188         return hash;
1189 }
1190
1191 int set_hashsize(const char *val, struct kernel_param *kp)
1192 {
1193         int i, bucket, hashsize, vmalloced;
1194         int old_vmalloced, old_size;
1195         int rnd;
1196         struct list_head *hash, *old_hash;
1197         struct nf_conntrack_tuple_hash *h;
1198
1199         /* On boot, we can set this without any fancy locking. */
1200         if (!nf_conntrack_htable_size)
1201                 return param_set_uint(val, kp);
1202
1203         hashsize = simple_strtol(val, NULL, 0);
1204         if (!hashsize)
1205                 return -EINVAL;
1206
1207         hash = alloc_hashtable(hashsize, &vmalloced);
1208         if (!hash)
1209                 return -ENOMEM;
1210
1211         /* We have to rehahs for the new table anyway, so we also can
1212          * use a newrandom seed */
1213         get_random_bytes(&rnd, 4);
1214
1215         write_lock_bh(&nf_conntrack_lock);
1216         for (i = 0; i < nf_conntrack_htable_size; i++) {
1217                 while (!list_empty(&nf_conntrack_hash[i])) {
1218                         h = list_entry(nf_conntrack_hash[i].next,
1219                                        struct nf_conntrack_tuple_hash, list);
1220                         list_del(&h->list);
1221                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1222                         list_add_tail(&h->list, &hash[bucket]);
1223                 }
1224         }
1225         old_size = nf_conntrack_htable_size;
1226         old_vmalloced = nf_conntrack_vmalloc;
1227         old_hash = nf_conntrack_hash;
1228
1229         nf_conntrack_htable_size = hashsize;
1230         nf_conntrack_vmalloc = vmalloced;
1231         nf_conntrack_hash = hash;
1232         nf_conntrack_hash_rnd = rnd;
1233         write_unlock_bh(&nf_conntrack_lock);
1234
1235         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1236         return 0;
1237 }
1238
1239 module_param_call(hashsize, set_hashsize, param_get_uint,
1240                   &nf_conntrack_htable_size, 0600);
1241
1242 int __init nf_conntrack_init(void)
1243 {
1244         int ret;
1245
1246         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1247          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1248         if (!nf_conntrack_htable_size) {
1249                 nf_conntrack_htable_size
1250                         = (((num_physpages << PAGE_SHIFT) / 16384)
1251                            / sizeof(struct list_head));
1252                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1253                         nf_conntrack_htable_size = 8192;
1254                 if (nf_conntrack_htable_size < 16)
1255                         nf_conntrack_htable_size = 16;
1256         }
1257         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1258
1259         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1260                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1261                nf_conntrack_max);
1262
1263         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1264                                             &nf_conntrack_vmalloc);
1265         if (!nf_conntrack_hash) {
1266                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1267                 goto err_out;
1268         }
1269
1270         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1271                                           sizeof(struct nf_conn));
1272         if (ret < 0) {
1273                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1274                 goto err_free_hash;
1275         }
1276
1277         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1278                                         sizeof(struct nf_conntrack_expect),
1279                                         0, 0, NULL, NULL);
1280         if (!nf_conntrack_expect_cachep) {
1281                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1282                 goto err_free_conntrack_slab;
1283         }
1284
1285         ret = nf_conntrack_proto_init();
1286         if (ret < 0)
1287                 goto out_free_expect_slab;
1288
1289         ret = nf_conntrack_helper_init();
1290         if (ret < 0)
1291                 goto out_fini_proto;
1292
1293         /* For use by REJECT target */
1294         rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
1295         rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1296
1297         /* Set up fake conntrack:
1298             - to never be deleted, not in any hashes */
1299         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1300         /*  - and look it like as a confirmed connection */
1301         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1302
1303         return ret;
1304
1305 out_fini_proto:
1306         nf_conntrack_proto_fini();
1307 out_free_expect_slab:
1308         kmem_cache_destroy(nf_conntrack_expect_cachep);
1309 err_free_conntrack_slab:
1310         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1311 err_free_hash:
1312         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1313                             nf_conntrack_htable_size);
1314 err_out:
1315         return -ENOMEM;
1316 }