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  * 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 #include <linux/mm.h>
  50
  51 #include <net/netfilter/nf_conntrack.h>
  52 #include <net/netfilter/nf_conntrack_l3proto.h>
  53 #include <net/netfilter/nf_conntrack_l4proto.h>
  54 #include <net/netfilter/nf_conntrack_expect.h>
  55 #include <net/netfilter/nf_conntrack_helper.h>
  56 #include <net/netfilter/nf_conntrack_core.h>
  57
  58 #define NF_CONNTRACK_VERSION    "0.5.0"
  59
  60 #if 0
  61 #define DEBUGP printk
  62 #else
  63 #define DEBUGP(format, args...)
  64 #endif
  65
  66 DEFINE_RWLOCK(nf_conntrack_lock);
  67 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  68
  69 /* nf_conntrack_standalone needs this */
  70 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  71 EXPORT_SYMBOL_GPL(nf_conntrack_count);
  72
  73 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
  74 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed);
  75
  76 unsigned int nf_conntrack_htable_size __read_mostly;
  77 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  78
  79 int nf_conntrack_max __read_mostly;
  80 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  81
  82 struct list_head *nf_conntrack_hash __read_mostly;
  83 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  84
  85 struct nf_conn nf_conntrack_untracked __read_mostly;
  86 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
  87
  88 unsigned int nf_ct_log_invalid __read_mostly;
  89 LIST_HEAD(unconfirmed);
  90 static int nf_conntrack_vmalloc __read_mostly;
  91
  92 static unsigned int nf_conntrack_next_id;
  93
  94 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  95 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  96
  97 /*
  98  * This scheme offers various size of "struct nf_conn" dependent on
  99  * features(helper, nat, ...)
 100  */
 101
 102 #define NF_CT_FEATURES_NAMELEN  256
 103 static struct {
 104         /* name of slab cache. printed in /proc/slabinfo */
 105         char *name;
 106
 107         /* size of slab cache */
 108         size_t size;
 109
 110         /* slab cache pointer */
 111         kmem_cache_t *cachep;
 112
 113         /* allocated slab cache + modules which uses this slab cache */
 114         int use;
 115
 116 } nf_ct_cache[NF_CT_F_NUM];
 117
 118 /* protect members of nf_ct_cache except of "use" */
 119 DEFINE_RWLOCK(nf_ct_cache_lock);
 120
 121 /* This avoids calling kmem_cache_create() with same name simultaneously */
 122 static DEFINE_MUTEX(nf_ct_cache_mutex);
 123
 124 static int nf_conntrack_hash_rnd_initted;
 125 static unsigned int nf_conntrack_hash_rnd;
 126
 127 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 128                                   unsigned int size, unsigned int rnd)
 129 {
 130         unsigned int a, b;
 131         a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
 132                   ((tuple->src.l3num) << 16) | tuple->dst.protonum);
 133         b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
 134                         (tuple->src.u.all << 16) | tuple->dst.u.all);
 135
 136         return jhash_2words(a, b, rnd) % size;
 137 }
 138
 139 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
 140 {
 141         return __hash_conntrack(tuple, nf_conntrack_htable_size,
 142                                 nf_conntrack_hash_rnd);
 143 }
 144
 145 int nf_conntrack_register_cache(u_int32_t features, const char *name,
 146                                 size_t size)
 147 {
 148         int ret = 0;
 149         char *cache_name;
 150         kmem_cache_t *cachep;
 151
 152         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
 153                features, name, size);
 154
 155         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
 156                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
 157                         features);
 158                 return -EINVAL;
 159         }
 160
 161         mutex_lock(&nf_ct_cache_mutex);
 162
 163         write_lock_bh(&nf_ct_cache_lock);
 164         /* e.g: multiple helpers are loaded */
 165         if (nf_ct_cache[features].use > 0) {
 166                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
 167                 if ((!strncmp(nf_ct_cache[features].name, name,
 168                               NF_CT_FEATURES_NAMELEN))
 169                     && nf_ct_cache[features].size == size) {
 170                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
 171                         nf_ct_cache[features].use++;
 172                         ret = 0;
 173                 } else
 174                         ret = -EBUSY;
 175
 176                 write_unlock_bh(&nf_ct_cache_lock);
 177                 mutex_unlock(&nf_ct_cache_mutex);
 178                 return ret;
 179         }
 180         write_unlock_bh(&nf_ct_cache_lock);
 181
 182         /*
 183          * The memory space for name of slab cache must be alive until
 184          * cache is destroyed.
 185          */
 186         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
 187         if (cache_name == NULL) {
 188                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
 189                 ret = -ENOMEM;
 190                 goto out_up_mutex;
 191         }
 192
 193         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
 194                                                 >= NF_CT_FEATURES_NAMELEN) {
 195                 printk("nf_conntrack_register_cache: name too long\n");
 196                 ret = -EINVAL;
 197                 goto out_free_name;
 198         }
 199
 200         cachep = kmem_cache_create(cache_name, size, 0, 0,
 201                                    NULL, NULL);
 202         if (!cachep) {
 203                 printk("nf_conntrack_register_cache: Can't create slab cache "
 204                        "for the features = 0x%x\n", features);
 205                 ret = -ENOMEM;
 206                 goto out_free_name;
 207         }
 208
 209         write_lock_bh(&nf_ct_cache_lock);
 210         nf_ct_cache[features].use = 1;
 211         nf_ct_cache[features].size = size;
 212         nf_ct_cache[features].cachep = cachep;
 213         nf_ct_cache[features].name = cache_name;
 214         write_unlock_bh(&nf_ct_cache_lock);
 215
 216         goto out_up_mutex;
 217
 218 out_free_name:
 219         kfree(cache_name);
 220 out_up_mutex:
 221         mutex_unlock(&nf_ct_cache_mutex);
 222         return ret;
 223 }
 224 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache);
 225
 226 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
 227 void nf_conntrack_unregister_cache(u_int32_t features)
 228 {
 229         kmem_cache_t *cachep;
 230         char *name;
 231
 232         /*
 233          * This assures that kmem_cache_create() isn't called before destroying
 234          * slab cache.
 235          */
 236         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
 237         mutex_lock(&nf_ct_cache_mutex);
 238
 239         write_lock_bh(&nf_ct_cache_lock);
 240         if (--nf_ct_cache[features].use > 0) {
 241                 write_unlock_bh(&nf_ct_cache_lock);
 242                 mutex_unlock(&nf_ct_cache_mutex);
 243                 return;
 244         }
 245         cachep = nf_ct_cache[features].cachep;
 246         name = nf_ct_cache[features].name;
 247         nf_ct_cache[features].cachep = NULL;
 248         nf_ct_cache[features].name = NULL;
 249         nf_ct_cache[features].size = 0;
 250         write_unlock_bh(&nf_ct_cache_lock);
 251
 252         synchronize_net();
 253
 254         kmem_cache_destroy(cachep);
 255         kfree(name);
 256
 257         mutex_unlock(&nf_ct_cache_mutex);
 258 }
 259 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache);
 260
 261 int
 262 nf_ct_get_tuple(const struct sk_buff *skb,
 263                 unsigned int nhoff,
 264                 unsigned int dataoff,
 265                 u_int16_t l3num,
 266                 u_int8_t protonum,
 267                 struct nf_conntrack_tuple *tuple,
 268                 const struct nf_conntrack_l3proto *l3proto,
 269                 const struct nf_conntrack_l4proto *l4proto)
 270 {
 271         NF_CT_TUPLE_U_BLANK(tuple);
 272
 273         tuple->src.l3num = l3num;
 274         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 275                 return 0;
 276
 277         tuple->dst.protonum = protonum;
 278         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 279
 280         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 281 }
 282 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 283
 284 int
 285 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 286                    const struct nf_conntrack_tuple *orig,
 287                    const struct nf_conntrack_l3proto *l3proto,
 288                    const struct nf_conntrack_l4proto *l4proto)
 289 {
 290         NF_CT_TUPLE_U_BLANK(inverse);
 291
 292         inverse->src.l3num = orig->src.l3num;
 293         if (l3proto->invert_tuple(inverse, orig) == 0)
 294                 return 0;
 295
 296         inverse->dst.dir = !orig->dst.dir;
 297
 298         inverse->dst.protonum = orig->dst.protonum;
 299         return l4proto->invert_tuple(inverse, orig);
 300 }
 301 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 302
 303 static void
 304 clean_from_lists(struct nf_conn *ct)
 305 {
 306         DEBUGP("clean_from_lists(%p)\n", ct);
 307         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 308         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
 309
 310         /* Destroy all pending expectations */
 311         nf_ct_remove_expectations(ct);
 312 }
 313
 314 static void
 315 destroy_conntrack(struct nf_conntrack *nfct)
 316 {
 317         struct nf_conn *ct = (struct nf_conn *)nfct;
 318         struct nf_conn_help *help = nfct_help(ct);
 319         struct nf_conntrack_l3proto *l3proto;
 320         struct nf_conntrack_l4proto *l4proto;
 321
 322         DEBUGP("destroy_conntrack(%p)\n", ct);
 323         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 324         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 325
 326         nf_conntrack_event(IPCT_DESTROY, ct);
 327         set_bit(IPS_DYING_BIT, &ct->status);
 328
 329         if (help && help->helper && help->helper->destroy)
 330                 help->helper->destroy(ct);
 331
 332         /* To make sure we don't get any weird locking issues here:
 333          * destroy_conntrack() MUST NOT be called with a write lock
 334          * to nf_conntrack_lock!!! -HW */
 335         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
 336         if (l3proto && l3proto->destroy)
 337                 l3proto->destroy(ct);
 338
 339         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 340         if (l4proto && l4proto->destroy)
 341                 l4proto->destroy(ct);
 342
 343         if (nf_conntrack_destroyed)
 344                 nf_conntrack_destroyed(ct);
 345
 346         write_lock_bh(&nf_conntrack_lock);
 347         /* Expectations will have been removed in clean_from_lists,
 348          * except TFTP can create an expectation on the first packet,
 349          * before connection is in the list, so we need to clean here,
 350          * too. */
 351         nf_ct_remove_expectations(ct);
 352
 353         /* We overload first tuple to link into unconfirmed list. */
 354         if (!nf_ct_is_confirmed(ct)) {
 355                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 356                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 357         }
 358
 359         NF_CT_STAT_INC(delete);
 360         write_unlock_bh(&nf_conntrack_lock);
 361
 362         if (ct->master)
 363                 nf_ct_put(ct->master);
 364
 365         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 366         nf_conntrack_free(ct);
 367 }
 368
 369 static void death_by_timeout(unsigned long ul_conntrack)
 370 {
 371         struct nf_conn *ct = (void *)ul_conntrack;
 372
 373         write_lock_bh(&nf_conntrack_lock);
 374         /* Inside lock so preempt is disabled on module removal path.
 375          * Otherwise we can get spurious warnings. */
 376         NF_CT_STAT_INC(delete_list);
 377         clean_from_lists(ct);
 378         write_unlock_bh(&nf_conntrack_lock);
 379         nf_ct_put(ct);
 380 }
 381
 382 struct nf_conntrack_tuple_hash *
 383 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 384                     const struct nf_conn *ignored_conntrack)
 385 {
 386         struct nf_conntrack_tuple_hash *h;
 387         unsigned int hash = hash_conntrack(tuple);
 388
 389         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
 390                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 391                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 392                         NF_CT_STAT_INC(found);
 393                         return h;
 394                 }
 395                 NF_CT_STAT_INC(searched);
 396         }
 397
 398         return NULL;
 399 }
 400 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 401
 402 /* Find a connection corresponding to a tuple. */
 403 struct nf_conntrack_tuple_hash *
 404 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
 405                       const struct nf_conn *ignored_conntrack)
 406 {
 407         struct nf_conntrack_tuple_hash *h;
 408
 409         read_lock_bh(&nf_conntrack_lock);
 410         h = __nf_conntrack_find(tuple, ignored_conntrack);
 411         if (h)
 412                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 413         read_unlock_bh(&nf_conntrack_lock);
 414
 415         return h;
 416 }
 417 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 418
 419 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 420                                        unsigned int hash,
 421                                        unsigned int repl_hash)
 422 {
 423         ct->id = ++nf_conntrack_next_id;
 424         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
 425                  &nf_conntrack_hash[hash]);
 426         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
 427                  &nf_conntrack_hash[repl_hash]);
 428 }
 429
 430 void nf_conntrack_hash_insert(struct nf_conn *ct)
 431 {
 432         unsigned int hash, repl_hash;
 433
 434         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 435         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 436
 437         write_lock_bh(&nf_conntrack_lock);
 438         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 439         write_unlock_bh(&nf_conntrack_lock);
 440 }
 441 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 442
 443 /* Confirm a connection given skb; places it in hash table */
 444 int
 445 __nf_conntrack_confirm(struct sk_buff **pskb)
 446 {
 447         unsigned int hash, repl_hash;
 448         struct nf_conntrack_tuple_hash *h;
 449         struct nf_conn *ct;
 450         struct nf_conn_help *help;
 451         enum ip_conntrack_info ctinfo;
 452
 453         ct = nf_ct_get(*pskb, &ctinfo);
 454
 455         /* ipt_REJECT uses nf_conntrack_attach to attach related
 456            ICMP/TCP RST packets in other direction.  Actual packet
 457            which created connection will be IP_CT_NEW or for an
 458            expected connection, IP_CT_RELATED. */
 459         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 460                 return NF_ACCEPT;
 461
 462         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 463         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 464
 465         /* We're not in hash table, and we refuse to set up related
 466            connections for unconfirmed conns.  But packet copies and
 467            REJECT will give spurious warnings here. */
 468         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 469
 470         /* No external references means noone else could have
 471            confirmed us. */
 472         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 473         DEBUGP("Confirming conntrack %p\n", ct);
 474
 475         write_lock_bh(&nf_conntrack_lock);
 476
 477         /* See if there's one in the list already, including reverse:
 478            NAT could have grabbed it without realizing, since we're
 479            not in the hash.  If there is, we lost race. */
 480         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
 481                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 482                                       &h->tuple))
 483                         goto out;
 484         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
 485                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 486                                       &h->tuple))
 487                         goto out;
 488
 489         /* Remove from unconfirmed list */
 490         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 491
 492         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 493         /* Timer relative to confirmation time, not original
 494            setting time, otherwise we'd get timer wrap in
 495            weird delay cases. */
 496         ct->timeout.expires += jiffies;
 497         add_timer(&ct->timeout);
 498         atomic_inc(&ct->ct_general.use);
 499         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 500         NF_CT_STAT_INC(insert);
 501         write_unlock_bh(&nf_conntrack_lock);
 502         help = nfct_help(ct);
 503         if (help && help->helper)
 504                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 505 #ifdef CONFIG_NF_NAT_NEEDED
 506         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 507             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 508                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 509 #endif
 510         nf_conntrack_event_cache(master_ct(ct) ?
 511                                  IPCT_RELATED : IPCT_NEW, *pskb);
 512         return NF_ACCEPT;
 513
 514 out:
 515         NF_CT_STAT_INC(insert_failed);
 516         write_unlock_bh(&nf_conntrack_lock);
 517         return NF_DROP;
 518 }
 519 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 520
 521 /* Returns true if a connection correspondings to the tuple (required
 522    for NAT). */
 523 int
 524 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 525                          const struct nf_conn *ignored_conntrack)
 526 {
 527         struct nf_conntrack_tuple_hash *h;
 528
 529         read_lock_bh(&nf_conntrack_lock);
 530         h = __nf_conntrack_find(tuple, ignored_conntrack);
 531         read_unlock_bh(&nf_conntrack_lock);
 532
 533         return h != NULL;
 534 }
 535 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 536
 537 /* There's a small race here where we may free a just-assured
 538    connection.  Too bad: we're in trouble anyway. */
 539 static int early_drop(struct list_head *chain)
 540 {
 541         /* Traverse backwards: gives us oldest, which is roughly LRU */
 542         struct nf_conntrack_tuple_hash *h;
 543         struct nf_conn *ct = NULL, *tmp;
 544         int dropped = 0;
 545
 546         read_lock_bh(&nf_conntrack_lock);
 547         list_for_each_entry_reverse(h, chain, list) {
 548                 tmp = nf_ct_tuplehash_to_ctrack(h);
 549                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
 550                         ct = tmp;
 551                         atomic_inc(&ct->ct_general.use);
 552                         break;
 553                 }
 554         }
 555         read_unlock_bh(&nf_conntrack_lock);
 556
 557         if (!ct)
 558                 return dropped;
 559
 560         if (del_timer(&ct->timeout)) {
 561                 death_by_timeout((unsigned long)ct);
 562                 dropped = 1;
 563                 NF_CT_STAT_INC(early_drop);
 564         }
 565         nf_ct_put(ct);
 566         return dropped;
 567 }
 568
 569 static struct nf_conn *
 570 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 571                      const struct nf_conntrack_tuple *repl,
 572                      const struct nf_conntrack_l3proto *l3proto,
 573                      u_int32_t features)
 574 {
 575         struct nf_conn *conntrack = NULL;
 576         struct nf_conntrack_helper *helper;
 577
 578         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 579                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 580                 nf_conntrack_hash_rnd_initted = 1;
 581         }
 582
 583         /* We don't want any race condition at early drop stage */
 584         atomic_inc(&nf_conntrack_count);
 585
 586         if (nf_conntrack_max
 587             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 588                 unsigned int hash = hash_conntrack(orig);
 589                 /* Try dropping from this hash chain. */
 590                 if (!early_drop(&nf_conntrack_hash[hash])) {
 591                         atomic_dec(&nf_conntrack_count);
 592                         if (net_ratelimit())
 593                                 printk(KERN_WARNING
 594                                        "nf_conntrack: table full, dropping"
 595                                        " packet.\n");
 596                         return ERR_PTR(-ENOMEM);
 597                 }
 598         }
 599
 600         /*  find features needed by this conntrack. */
 601         features |= l3proto->get_features(orig);
 602
 603         /* FIXME: protect helper list per RCU */
 604         read_lock_bh(&nf_conntrack_lock);
 605         helper = __nf_ct_helper_find(repl);
 606         /* NAT might want to assign a helper later */
 607         if (helper || features & NF_CT_F_NAT)
 608                 features |= NF_CT_F_HELP;
 609         read_unlock_bh(&nf_conntrack_lock);
 610
 611         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 612
 613         read_lock_bh(&nf_ct_cache_lock);
 614
 615         if (unlikely(!nf_ct_cache[features].use)) {
 616                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
 617                         features);
 618                 goto out;
 619         }
 620
 621         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
 622         if (conntrack == NULL) {
 623                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
 624                 goto out;
 625         }
 626
 627         memset(conntrack, 0, nf_ct_cache[features].size);
 628         conntrack->features = features;
 629         atomic_set(&conntrack->ct_general.use, 1);
 630         conntrack->ct_general.destroy = destroy_conntrack;
 631         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 632         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 633         /* Don't set timer yet: wait for confirmation */
 634         init_timer(&conntrack->timeout);
 635         conntrack->timeout.data = (unsigned long)conntrack;
 636         conntrack->timeout.function = death_by_timeout;
 637         read_unlock_bh(&nf_ct_cache_lock);
 638
 639         return conntrack;
 640 out:
 641         read_unlock_bh(&nf_ct_cache_lock);
 642         atomic_dec(&nf_conntrack_count);
 643         return conntrack;
 644 }
 645
 646 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 647                                    const struct nf_conntrack_tuple *repl)
 648 {
 649         struct nf_conntrack_l3proto *l3proto;
 650
 651         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
 652         return __nf_conntrack_alloc(orig, repl, l3proto, 0);
 653 }
 654 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 655
 656 void nf_conntrack_free(struct nf_conn *conntrack)
 657 {
 658         u_int32_t features = conntrack->features;
 659         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
 660         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
 661                conntrack);
 662         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
 663         atomic_dec(&nf_conntrack_count);
 664 }
 665 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 666
 667 /* Allocate a new conntrack: we return -ENOMEM if classification
 668    failed due to stress.  Otherwise it really is unclassifiable. */
 669 static struct nf_conntrack_tuple_hash *
 670 init_conntrack(const struct nf_conntrack_tuple *tuple,
 671                struct nf_conntrack_l3proto *l3proto,
 672                struct nf_conntrack_l4proto *l4proto,
 673                struct sk_buff *skb,
 674                unsigned int dataoff)
 675 {
 676         struct nf_conn *conntrack;
 677         struct nf_conntrack_tuple repl_tuple;
 678         struct nf_conntrack_expect *exp;
 679         u_int32_t features = 0;
 680
 681         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 682                 DEBUGP("Can't invert tuple.\n");
 683                 return NULL;
 684         }
 685
 686         read_lock_bh(&nf_conntrack_lock);
 687         exp = __nf_conntrack_expect_find(tuple);
 688         if (exp && exp->helper)
 689                 features = NF_CT_F_HELP;
 690         read_unlock_bh(&nf_conntrack_lock);
 691
 692         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
 693         if (conntrack == NULL || IS_ERR(conntrack)) {
 694                 DEBUGP("Can't allocate conntrack.\n");
 695                 return (struct nf_conntrack_tuple_hash *)conntrack;
 696         }
 697
 698         if (!l4proto->new(conntrack, skb, dataoff)) {
 699                 nf_conntrack_free(conntrack);
 700                 DEBUGP("init conntrack: can't track with proto module\n");
 701                 return NULL;
 702         }
 703
 704         write_lock_bh(&nf_conntrack_lock);
 705         exp = find_expectation(tuple);
 706
 707         if (exp) {
 708                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 709                         conntrack, exp);
 710                 /* Welcome, Mr. Bond.  We've been expecting you... */
 711                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 712                 conntrack->master = exp->master;
 713                 if (exp->helper)
 714                         nfct_help(conntrack)->helper = exp->helper;
 715 #ifdef CONFIG_NF_CONNTRACK_MARK
 716                 conntrack->mark = exp->master->mark;
 717 #endif
 718 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 719                 conntrack->secmark = exp->master->secmark;
 720 #endif
 721                 nf_conntrack_get(&conntrack->master->ct_general);
 722                 NF_CT_STAT_INC(expect_new);
 723         } else {
 724                 struct nf_conn_help *help = nfct_help(conntrack);
 725
 726                 if (help)
 727                         help->helper = __nf_ct_helper_find(&repl_tuple);
 728                 NF_CT_STAT_INC(new);
 729         }
 730
 731         /* Overload tuple linked list to put us in unconfirmed list. */
 732         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 733
 734         write_unlock_bh(&nf_conntrack_lock);
 735
 736         if (exp) {
 737                 if (exp->expectfn)
 738                         exp->expectfn(conntrack, exp);
 739                 nf_conntrack_expect_put(exp);
 740         }
 741
 742         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 743 }
 744
 745 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 746 static inline struct nf_conn *
 747 resolve_normal_ct(struct sk_buff *skb,
 748                   unsigned int dataoff,
 749                   u_int16_t l3num,
 750                   u_int8_t protonum,
 751                   struct nf_conntrack_l3proto *l3proto,
 752                   struct nf_conntrack_l4proto *l4proto,
 753                   int *set_reply,
 754                   enum ip_conntrack_info *ctinfo)
 755 {
 756         struct nf_conntrack_tuple tuple;
 757         struct nf_conntrack_tuple_hash *h;
 758         struct nf_conn *ct;
 759
 760         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
 761                              dataoff, l3num, protonum, &tuple, l3proto,
 762                              l4proto)) {
 763                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
 764                 return NULL;
 765         }
 766
 767         /* look for tuple match */
 768         h = nf_conntrack_find_get(&tuple, NULL);
 769         if (!h) {
 770                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 771                 if (!h)
 772                         return NULL;
 773                 if (IS_ERR(h))
 774                         return (void *)h;
 775         }
 776         ct = nf_ct_tuplehash_to_ctrack(h);
 777
 778         /* It exists; we have (non-exclusive) reference. */
 779         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 780                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 781                 /* Please set reply bit if this packet OK */
 782                 *set_reply = 1;
 783         } else {
 784                 /* Once we've had two way comms, always ESTABLISHED. */
 785                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 786                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
 787                         *ctinfo = IP_CT_ESTABLISHED;
 788                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 789                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
 790                         *ctinfo = IP_CT_RELATED;
 791                 } else {
 792                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
 793                         *ctinfo = IP_CT_NEW;
 794                 }
 795                 *set_reply = 0;
 796         }
 797         skb->nfct = &ct->ct_general;
 798         skb->nfctinfo = *ctinfo;
 799         return ct;
 800 }
 801
 802 unsigned int
 803 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 804 {
 805         struct nf_conn *ct;
 806         enum ip_conntrack_info ctinfo;
 807         struct nf_conntrack_l3proto *l3proto;
 808         struct nf_conntrack_l4proto *l4proto;
 809         unsigned int dataoff;
 810         u_int8_t protonum;
 811         int set_reply = 0;
 812         int ret;
 813
 814         /* Previously seen (loopback or untracked)?  Ignore. */
 815         if ((*pskb)->nfct) {
 816                 NF_CT_STAT_INC(ignore);
 817                 return NF_ACCEPT;
 818         }
 819
 820         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 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(error);
 834                 NF_CT_STAT_INC(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(invalid);
 843                 return NF_ACCEPT;
 844         }
 845
 846         if (IS_ERR(ct)) {
 847                 /* Too stressed to deal. */
 848                 NF_CT_STAT_INC(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(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         return nf_ct_invert_tuple(inverse, orig,
 876                                   __nf_ct_l3proto_find(orig->src.l3num),
 877                                   __nf_ct_l4proto_find(orig->src.l3num,
 878                                                      orig->dst.protonum));
 879 }
 880 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 881
 882 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 883    implicitly racy: see __nf_conntrack_confirm */
 884 void nf_conntrack_alter_reply(struct nf_conn *ct,
 885                               const struct nf_conntrack_tuple *newreply)
 886 {
 887         struct nf_conn_help *help = nfct_help(ct);
 888
 889         write_lock_bh(&nf_conntrack_lock);
 890         /* Should be unconfirmed, so not in hash table yet */
 891         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 892
 893         DEBUGP("Altering reply tuple of %p to ", ct);
 894         NF_CT_DUMP_TUPLE(newreply);
 895
 896         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 897         if (!ct->master && help && help->expecting == 0)
 898                 help->helper = __nf_ct_helper_find(newreply);
 899         write_unlock_bh(&nf_conntrack_lock);
 900 }
 901 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 902
 903 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 904 void __nf_ct_refresh_acct(struct nf_conn *ct,
 905                           enum ip_conntrack_info ctinfo,
 906                           const struct sk_buff *skb,
 907                           unsigned long extra_jiffies,
 908                           int do_acct)
 909 {
 910         int event = 0;
 911
 912         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 913         NF_CT_ASSERT(skb);
 914
 915         write_lock_bh(&nf_conntrack_lock);
 916
 917         /* Only update if this is not a fixed timeout */
 918         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 919                 write_unlock_bh(&nf_conntrack_lock);
 920                 return;
 921         }
 922
 923         /* If not in hash table, timer will not be active yet */
 924         if (!nf_ct_is_confirmed(ct)) {
 925                 ct->timeout.expires = extra_jiffies;
 926                 event = IPCT_REFRESH;
 927         } else {
 928                 unsigned long newtime = jiffies + extra_jiffies;
 929
 930                 /* Only update the timeout if the new timeout is at least
 931                    HZ jiffies from the old timeout. Need del_timer for race
 932                    avoidance (may already be dying). */
 933                 if (newtime - ct->timeout.expires >= HZ
 934                     && del_timer(&ct->timeout)) {
 935                         ct->timeout.expires = newtime;
 936                         add_timer(&ct->timeout);
 937                         event = IPCT_REFRESH;
 938                 }
 939         }
 940
 941 #ifdef CONFIG_NF_CT_ACCT
 942         if (do_acct) {
 943                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 944                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 945                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
 946
 947                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 948                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 949                         event |= IPCT_COUNTER_FILLING;
 950         }
 951 #endif
 952
 953         write_unlock_bh(&nf_conntrack_lock);
 954
 955         /* must be unlocked when calling event cache */
 956         if (event)
 957                 nf_conntrack_event_cache(event, skb);
 958 }
 959 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 960
 961 #if defined(CONFIG_NF_CT_NETLINK) || \
 962     defined(CONFIG_NF_CT_NETLINK_MODULE)
 963
 964 #include <linux/netfilter/nfnetlink.h>
 965 #include <linux/netfilter/nfnetlink_conntrack.h>
 966 #include <linux/mutex.h>
 967
 968
 969 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 970  * in ip_conntrack_core, since we don't want the protocols to autoload
 971  * or depend on ctnetlink */
 972 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
 973                                const struct nf_conntrack_tuple *tuple)
 974 {
 975         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
 976                 &tuple->src.u.tcp.port);
 977         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
 978                 &tuple->dst.u.tcp.port);
 979         return 0;
 980
 981 nfattr_failure:
 982         return -1;
 983 }
 984 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
 985
 986 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
 987         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
 988         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
 989 };
 990
 991 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
 992                                struct nf_conntrack_tuple *t)
 993 {
 994         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
 995                 return -EINVAL;
 996
 997         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
 998                 return -EINVAL;
 999
1000         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1001         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1002
1003         return 0;
1004 }
1005 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1006 #endif
1007
1008 /* Used by ipt_REJECT and ip6t_REJECT. */
1009 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1010 {
1011         struct nf_conn *ct;
1012         enum ip_conntrack_info ctinfo;
1013
1014         /* This ICMP is in reverse direction to the packet which caused it */
1015         ct = nf_ct_get(skb, &ctinfo);
1016         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1017                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1018         else
1019                 ctinfo = IP_CT_RELATED;
1020
1021         /* Attach to new skbuff, and increment count */
1022         nskb->nfct = &ct->ct_general;
1023         nskb->nfctinfo = ctinfo;
1024         nf_conntrack_get(nskb->nfct);
1025 }
1026 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1027
1028 static inline int
1029 do_iter(const struct nf_conntrack_tuple_hash *i,
1030         int (*iter)(struct nf_conn *i, void *data),
1031         void *data)
1032 {
1033         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1034 }
1035
1036 /* Bring out ya dead! */
1037 static struct nf_conn *
1038 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1039                 void *data, unsigned int *bucket)
1040 {
1041         struct nf_conntrack_tuple_hash *h;
1042         struct nf_conn *ct;
1043
1044         write_lock_bh(&nf_conntrack_lock);
1045         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1046                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1047                         ct = nf_ct_tuplehash_to_ctrack(h);
1048                         if (iter(ct, data))
1049                                 goto found;
1050                 }
1051         }
1052         list_for_each_entry(h, &unconfirmed, list) {
1053                 ct = nf_ct_tuplehash_to_ctrack(h);
1054                 if (iter(ct, data))
1055                         goto found;
1056         }
1057         write_unlock_bh(&nf_conntrack_lock);
1058         return NULL;
1059 found:
1060         atomic_inc(&ct->ct_general.use);
1061         write_unlock_bh(&nf_conntrack_lock);
1062         return ct;
1063 }
1064
1065 void
1066 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1067 {
1068         struct nf_conn *ct;
1069         unsigned int bucket = 0;
1070
1071         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1072                 /* Time to push up daises... */
1073                 if (del_timer(&ct->timeout))
1074                         death_by_timeout((unsigned long)ct);
1075                 /* ... else the timer will get him soon. */
1076
1077                 nf_ct_put(ct);
1078         }
1079 }
1080 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1081
1082 static int kill_all(struct nf_conn *i, void *data)
1083 {
1084         return 1;
1085 }
1086
1087 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1088 {
1089         if (vmalloced)
1090                 vfree(hash);
1091         else
1092                 free_pages((unsigned long)hash,
1093                            get_order(sizeof(struct list_head) * size));
1094 }
1095
1096 void nf_conntrack_flush()
1097 {
1098         nf_ct_iterate_cleanup(kill_all, NULL);
1099 }
1100 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1101
1102 /* Mishearing the voices in his head, our hero wonders how he's
1103    supposed to kill the mall. */
1104 void nf_conntrack_cleanup(void)
1105 {
1106         int i;
1107
1108         ip_ct_attach = NULL;
1109
1110         /* This makes sure all current packets have passed through
1111            netfilter framework.  Roll on, two-stage module
1112            delete... */
1113         synchronize_net();
1114
1115         nf_ct_event_cache_flush();
1116  i_see_dead_people:
1117         nf_conntrack_flush();
1118         if (atomic_read(&nf_conntrack_count) != 0) {
1119                 schedule();
1120                 goto i_see_dead_people;
1121         }
1122         /* wait until all references to nf_conntrack_untracked are dropped */
1123         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1124                 schedule();
1125
1126         for (i = 0; i < NF_CT_F_NUM; i++) {
1127                 if (nf_ct_cache[i].use == 0)
1128                         continue;
1129
1130                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1131                 nf_ct_cache[i].use = 1;
1132                 nf_conntrack_unregister_cache(i);
1133         }
1134         kmem_cache_destroy(nf_conntrack_expect_cachep);
1135         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1136                             nf_conntrack_htable_size);
1137
1138         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1139
1140         /* free l3proto protocol tables */
1141         for (i = 0; i < PF_MAX; i++)
1142                 if (nf_ct_protos[i]) {
1143                         kfree(nf_ct_protos[i]);
1144                         nf_ct_protos[i] = NULL;
1145                 }
1146 }
1147
1148 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1149 {
1150         struct list_head *hash;
1151         unsigned int i;
1152
1153         *vmalloced = 0;
1154         hash = (void*)__get_free_pages(GFP_KERNEL,
1155                                        get_order(sizeof(struct list_head)
1156                                                  * size));
1157         if (!hash) {
1158                 *vmalloced = 1;
1159                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1160                 hash = vmalloc(sizeof(struct list_head) * size);
1161         }
1162
1163         if (hash)
1164                 for (i = 0; i < size; i++)
1165                         INIT_LIST_HEAD(&hash[i]);
1166
1167         return hash;
1168 }
1169
1170 int set_hashsize(const char *val, struct kernel_param *kp)
1171 {
1172         int i, bucket, hashsize, vmalloced;
1173         int old_vmalloced, old_size;
1174         int rnd;
1175         struct list_head *hash, *old_hash;
1176         struct nf_conntrack_tuple_hash *h;
1177
1178         /* On boot, we can set this without any fancy locking. */
1179         if (!nf_conntrack_htable_size)
1180                 return param_set_uint(val, kp);
1181
1182         hashsize = simple_strtol(val, NULL, 0);
1183         if (!hashsize)
1184                 return -EINVAL;
1185
1186         hash = alloc_hashtable(hashsize, &vmalloced);
1187         if (!hash)
1188                 return -ENOMEM;
1189
1190         /* We have to rehahs for the new table anyway, so we also can
1191          * use a newrandom seed */
1192         get_random_bytes(&rnd, 4);
1193
1194         write_lock_bh(&nf_conntrack_lock);
1195         for (i = 0; i < nf_conntrack_htable_size; i++) {
1196                 while (!list_empty(&nf_conntrack_hash[i])) {
1197                         h = list_entry(nf_conntrack_hash[i].next,
1198                                        struct nf_conntrack_tuple_hash, list);
1199                         list_del(&h->list);
1200                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1201                         list_add_tail(&h->list, &hash[bucket]);
1202                 }
1203         }
1204         old_size = nf_conntrack_htable_size;
1205         old_vmalloced = nf_conntrack_vmalloc;
1206         old_hash = nf_conntrack_hash;
1207
1208         nf_conntrack_htable_size = hashsize;
1209         nf_conntrack_vmalloc = vmalloced;
1210         nf_conntrack_hash = hash;
1211         nf_conntrack_hash_rnd = rnd;
1212         write_unlock_bh(&nf_conntrack_lock);
1213
1214         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1215         return 0;
1216 }
1217
1218 module_param_call(hashsize, set_hashsize, param_get_uint,
1219                   &nf_conntrack_htable_size, 0600);
1220
1221 int __init nf_conntrack_init(void)
1222 {
1223         unsigned int i;
1224         int ret;
1225
1226         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1227          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1228         if (!nf_conntrack_htable_size) {
1229                 nf_conntrack_htable_size
1230                         = (((num_physpages << PAGE_SHIFT) / 16384)
1231                            / sizeof(struct list_head));
1232                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1233                         nf_conntrack_htable_size = 8192;
1234                 if (nf_conntrack_htable_size < 16)
1235                         nf_conntrack_htable_size = 16;
1236         }
1237         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1238
1239         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1240                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1241                nf_conntrack_max);
1242
1243         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1244                                             &nf_conntrack_vmalloc);
1245         if (!nf_conntrack_hash) {
1246                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1247                 goto err_out;
1248         }
1249
1250         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1251                                           sizeof(struct nf_conn));
1252         if (ret < 0) {
1253                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1254                 goto err_free_hash;
1255         }
1256
1257         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1258                                         sizeof(struct nf_conntrack_expect),
1259                                         0, 0, NULL, NULL);
1260         if (!nf_conntrack_expect_cachep) {
1261                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1262                 goto err_free_conntrack_slab;
1263         }
1264
1265         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1266         if (ret < 0)
1267                 goto out_free_expect_slab;
1268
1269         /* Don't NEED lock here, but good form anyway. */
1270         write_lock_bh(&nf_conntrack_lock);
1271         for (i = 0; i < AF_MAX; i++)
1272                 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1273         write_unlock_bh(&nf_conntrack_lock);
1274
1275         /* For use by REJECT target */
1276         ip_ct_attach = __nf_conntrack_attach;
1277
1278         /* Set up fake conntrack:
1279             - to never be deleted, not in any hashes */
1280         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1281         /*  - and look it like as a confirmed connection */
1282         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1283
1284         return ret;
1285
1286 out_free_expect_slab:
1287         kmem_cache_destroy(nf_conntrack_expect_cachep);
1288 err_free_conntrack_slab:
1289         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1290 err_free_hash:
1291         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1292                             nf_conntrack_htable_size);
1293 err_out:
1294         return -ENOMEM;
1295 }