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   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
  14  *      - new API and handling of conntrack/nat helpers
  15  *      - now capable of multiple expectations for one master
  16  * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
  17  *      - add usage/reference counts to ip_conntrack_expect
  18  *      - export ip_conntrack[_expect]_{find_get,put} functions
  19  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  20  *      - generalize L3 protocol denendent part.
  21  * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  22  *      - add support various size of conntrack structures.
  23  * 26 Jan 2006: Harald Welte <laforge@netfilter.org>
  24  *      - restructure nf_conn (introduce nf_conn_help)
  25  *      - redesign 'features' how they were originally intended
  26  * 26 Feb 2006: Pablo Neira Ayuso <pablo@eurodev.net>
  27  *      - add support for L3 protocol module load on demand.
  28  *
  29  * Derived from net/ipv4/netfilter/ip_conntrack_core.c
  30  */
  31
  32 #include <linux/types.h>
  33 #include <linux/netfilter.h>
  34 #include <linux/module.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/vmalloc.h>
  38 #include <linux/stddef.h>
  39 #include <linux/slab.h>
  40 #include <linux/random.h>
  41 #include <linux/jhash.h>
  42 #include <linux/err.h>
  43 #include <linux/percpu.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/notifier.h>
  46 #include <linux/kernel.h>
  47 #include <linux/netdevice.h>
  48 #include <linux/socket.h>
  49
  50 /* This rwlock protects the main hash table, protocol/helper/expected
  51    registrations, conntrack timers*/
  52 #define ASSERT_READ_LOCK(x)
  53 #define ASSERT_WRITE_LOCK(x)
  54
  55 #include <net/netfilter/nf_conntrack.h>
  56 #include <net/netfilter/nf_conntrack_l3proto.h>
  57 #include <net/netfilter/nf_conntrack_protocol.h>
  58 #include <net/netfilter/nf_conntrack_expect.h>
  59 #include <net/netfilter/nf_conntrack_helper.h>
  60 #include <net/netfilter/nf_conntrack_core.h>
  61
  62 #define NF_CONNTRACK_VERSION    "0.5.0"
  63
  64 #if 0
  65 #define DEBUGP printk
  66 #else
  67 #define DEBUGP(format, args...)
  68 #endif
  69
  70 DEFINE_RWLOCK(nf_conntrack_lock);
  71
  72 /* nf_conntrack_standalone needs this */
  73 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  74
  75 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack) = NULL;
  76 unsigned int nf_conntrack_htable_size __read_mostly = 0;
  77 int nf_conntrack_max __read_mostly;
  78 struct list_head *nf_conntrack_hash __read_mostly;
  79 struct nf_conn nf_conntrack_untracked;
  80 unsigned int nf_ct_log_invalid __read_mostly;
  81 LIST_HEAD(unconfirmed);
  82 static int nf_conntrack_vmalloc __read_mostly;
  83
  84 static unsigned int nf_conntrack_next_id;
  85
  86 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  87 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  88
  89 /*
  90  * This scheme offers various size of "struct nf_conn" dependent on
  91  * features(helper, nat, ...)
  92  */
  93
  94 #define NF_CT_FEATURES_NAMELEN  256
  95 static struct {
  96         /* name of slab cache. printed in /proc/slabinfo */
  97         char *name;
  98
  99         /* size of slab cache */
 100         size_t size;
 101
 102         /* slab cache pointer */
 103         kmem_cache_t *cachep;
 104
 105         /* allocated slab cache + modules which uses this slab cache */
 106         int use;
 107
 108 } nf_ct_cache[NF_CT_F_NUM];
 109
 110 /* protect members of nf_ct_cache except of "use" */
 111 DEFINE_RWLOCK(nf_ct_cache_lock);
 112
 113 /* This avoids calling kmem_cache_create() with same name simultaneously */
 114 static DEFINE_MUTEX(nf_ct_cache_mutex);
 115
 116 static int nf_conntrack_hash_rnd_initted;
 117 static unsigned int nf_conntrack_hash_rnd;
 118
 119 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 120                                   unsigned int size, unsigned int rnd)
 121 {
 122         unsigned int a, b;
 123         a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
 124                   ((tuple->src.l3num) << 16) | tuple->dst.protonum);
 125         b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
 126                         (tuple->src.u.all << 16) | tuple->dst.u.all);
 127
 128         return jhash_2words(a, b, rnd) % size;
 129 }
 130
 131 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
 132 {
 133         return __hash_conntrack(tuple, nf_conntrack_htable_size,
 134                                 nf_conntrack_hash_rnd);
 135 }
 136
 137 int nf_conntrack_register_cache(u_int32_t features, const char *name,
 138                                 size_t size)
 139 {
 140         int ret = 0;
 141         char *cache_name;
 142         kmem_cache_t *cachep;
 143
 144         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
 145                features, name, size);
 146
 147         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
 148                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
 149                         features);
 150                 return -EINVAL;
 151         }
 152
 153         mutex_lock(&nf_ct_cache_mutex);
 154
 155         write_lock_bh(&nf_ct_cache_lock);
 156         /* e.g: multiple helpers are loaded */
 157         if (nf_ct_cache[features].use > 0) {
 158                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
 159                 if ((!strncmp(nf_ct_cache[features].name, name,
 160                               NF_CT_FEATURES_NAMELEN))
 161                     && nf_ct_cache[features].size == size) {
 162                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
 163                         nf_ct_cache[features].use++;
 164                         ret = 0;
 165                 } else
 166                         ret = -EBUSY;
 167
 168                 write_unlock_bh(&nf_ct_cache_lock);
 169                 mutex_unlock(&nf_ct_cache_mutex);
 170                 return ret;
 171         }
 172         write_unlock_bh(&nf_ct_cache_lock);
 173
 174         /*
 175          * The memory space for name of slab cache must be alive until
 176          * cache is destroyed.
 177          */
 178         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
 179         if (cache_name == NULL) {
 180                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
 181                 ret = -ENOMEM;
 182                 goto out_up_mutex;
 183         }
 184
 185         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
 186                                                 >= NF_CT_FEATURES_NAMELEN) {
 187                 printk("nf_conntrack_register_cache: name too long\n");
 188                 ret = -EINVAL;
 189                 goto out_free_name;
 190         }
 191
 192         cachep = kmem_cache_create(cache_name, size, 0, 0,
 193                                    NULL, NULL);
 194         if (!cachep) {
 195                 printk("nf_conntrack_register_cache: Can't create slab cache "
 196                        "for the features = 0x%x\n", features);
 197                 ret = -ENOMEM;
 198                 goto out_free_name;
 199         }
 200
 201         write_lock_bh(&nf_ct_cache_lock);
 202         nf_ct_cache[features].use = 1;
 203         nf_ct_cache[features].size = size;
 204         nf_ct_cache[features].cachep = cachep;
 205         nf_ct_cache[features].name = cache_name;
 206         write_unlock_bh(&nf_ct_cache_lock);
 207
 208         goto out_up_mutex;
 209
 210 out_free_name:
 211         kfree(cache_name);
 212 out_up_mutex:
 213         mutex_unlock(&nf_ct_cache_mutex);
 214         return ret;
 215 }
 216
 217 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
 218 void nf_conntrack_unregister_cache(u_int32_t features)
 219 {
 220         kmem_cache_t *cachep;
 221         char *name;
 222
 223         /*
 224          * This assures that kmem_cache_create() isn't called before destroying
 225          * slab cache.
 226          */
 227         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
 228         mutex_lock(&nf_ct_cache_mutex);
 229
 230         write_lock_bh(&nf_ct_cache_lock);
 231         if (--nf_ct_cache[features].use > 0) {
 232                 write_unlock_bh(&nf_ct_cache_lock);
 233                 mutex_unlock(&nf_ct_cache_mutex);
 234                 return;
 235         }
 236         cachep = nf_ct_cache[features].cachep;
 237         name = nf_ct_cache[features].name;
 238         nf_ct_cache[features].cachep = NULL;
 239         nf_ct_cache[features].name = NULL;
 240         nf_ct_cache[features].size = 0;
 241         write_unlock_bh(&nf_ct_cache_lock);
 242
 243         synchronize_net();
 244
 245         kmem_cache_destroy(cachep);
 246         kfree(name);
 247
 248         mutex_unlock(&nf_ct_cache_mutex);
 249 }
 250
 251 int
 252 nf_ct_get_tuple(const struct sk_buff *skb,
 253                 unsigned int nhoff,
 254                 unsigned int dataoff,
 255                 u_int16_t l3num,
 256                 u_int8_t protonum,
 257                 struct nf_conntrack_tuple *tuple,
 258                 const struct nf_conntrack_l3proto *l3proto,
 259                 const struct nf_conntrack_protocol *protocol)
 260 {
 261         NF_CT_TUPLE_U_BLANK(tuple);
 262
 263         tuple->src.l3num = l3num;
 264         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 265                 return 0;
 266
 267         tuple->dst.protonum = protonum;
 268         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 269
 270         return protocol->pkt_to_tuple(skb, dataoff, tuple);
 271 }
 272
 273 int
 274 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 275                    const struct nf_conntrack_tuple *orig,
 276                    const struct nf_conntrack_l3proto *l3proto,
 277                    const struct nf_conntrack_protocol *protocol)
 278 {
 279         NF_CT_TUPLE_U_BLANK(inverse);
 280
 281         inverse->src.l3num = orig->src.l3num;
 282         if (l3proto->invert_tuple(inverse, orig) == 0)
 283                 return 0;
 284
 285         inverse->dst.dir = !orig->dst.dir;
 286
 287         inverse->dst.protonum = orig->dst.protonum;
 288         return protocol->invert_tuple(inverse, orig);
 289 }
 290
 291 static void
 292 clean_from_lists(struct nf_conn *ct)
 293 {
 294         DEBUGP("clean_from_lists(%p)\n", ct);
 295         ASSERT_WRITE_LOCK(&nf_conntrack_lock);
 296         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 297         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
 298
 299         /* Destroy all pending expectations */
 300         nf_ct_remove_expectations(ct);
 301 }
 302
 303 static void
 304 destroy_conntrack(struct nf_conntrack *nfct)
 305 {
 306         struct nf_conn *ct = (struct nf_conn *)nfct;
 307         struct nf_conntrack_l3proto *l3proto;
 308         struct nf_conntrack_protocol *proto;
 309
 310         DEBUGP("destroy_conntrack(%p)\n", ct);
 311         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 312         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 313
 314         nf_conntrack_event(IPCT_DESTROY, ct);
 315         set_bit(IPS_DYING_BIT, &ct->status);
 316
 317         /* To make sure we don't get any weird locking issues here:
 318          * destroy_conntrack() MUST NOT be called with a write lock
 319          * to nf_conntrack_lock!!! -HW */
 320         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
 321         if (l3proto && l3proto->destroy)
 322                 l3proto->destroy(ct);
 323
 324         proto = __nf_ct_proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 325         if (proto && proto->destroy)
 326                 proto->destroy(ct);
 327
 328         if (nf_conntrack_destroyed)
 329                 nf_conntrack_destroyed(ct);
 330
 331         write_lock_bh(&nf_conntrack_lock);
 332         /* Expectations will have been removed in clean_from_lists,
 333          * except TFTP can create an expectation on the first packet,
 334          * before connection is in the list, so we need to clean here,
 335          * too. */
 336         nf_ct_remove_expectations(ct);
 337
 338         /* We overload first tuple to link into unconfirmed list. */
 339         if (!nf_ct_is_confirmed(ct)) {
 340                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 341                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 342         }
 343
 344         NF_CT_STAT_INC(delete);
 345         write_unlock_bh(&nf_conntrack_lock);
 346
 347         if (ct->master)
 348                 nf_ct_put(ct->master);
 349
 350         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 351         nf_conntrack_free(ct);
 352 }
 353
 354 static void death_by_timeout(unsigned long ul_conntrack)
 355 {
 356         struct nf_conn *ct = (void *)ul_conntrack;
 357
 358         write_lock_bh(&nf_conntrack_lock);
 359         /* Inside lock so preempt is disabled on module removal path.
 360          * Otherwise we can get spurious warnings. */
 361         NF_CT_STAT_INC(delete_list);
 362         clean_from_lists(ct);
 363         write_unlock_bh(&nf_conntrack_lock);
 364         nf_ct_put(ct);
 365 }
 366
 367 struct nf_conntrack_tuple_hash *
 368 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 369                     const struct nf_conn *ignored_conntrack)
 370 {
 371         struct nf_conntrack_tuple_hash *h;
 372         unsigned int hash = hash_conntrack(tuple);
 373
 374         ASSERT_READ_LOCK(&nf_conntrack_lock);
 375         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
 376                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 377                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 378                         NF_CT_STAT_INC(found);
 379                         return h;
 380                 }
 381                 NF_CT_STAT_INC(searched);
 382         }
 383
 384         return NULL;
 385 }
 386
 387 /* Find a connection corresponding to a tuple. */
 388 struct nf_conntrack_tuple_hash *
 389 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
 390                       const struct nf_conn *ignored_conntrack)
 391 {
 392         struct nf_conntrack_tuple_hash *h;
 393
 394         read_lock_bh(&nf_conntrack_lock);
 395         h = __nf_conntrack_find(tuple, ignored_conntrack);
 396         if (h)
 397                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 398         read_unlock_bh(&nf_conntrack_lock);
 399
 400         return h;
 401 }
 402
 403 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 404                                        unsigned int hash,
 405                                        unsigned int repl_hash)
 406 {
 407         ct->id = ++nf_conntrack_next_id;
 408         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
 409                  &nf_conntrack_hash[hash]);
 410         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
 411                  &nf_conntrack_hash[repl_hash]);
 412 }
 413
 414 void nf_conntrack_hash_insert(struct nf_conn *ct)
 415 {
 416         unsigned int hash, repl_hash;
 417
 418         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 419         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 420
 421         write_lock_bh(&nf_conntrack_lock);
 422         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 423         write_unlock_bh(&nf_conntrack_lock);
 424 }
 425
 426 /* Confirm a connection given skb; places it in hash table */
 427 int
 428 __nf_conntrack_confirm(struct sk_buff **pskb)
 429 {
 430         unsigned int hash, repl_hash;
 431         struct nf_conntrack_tuple_hash *h;
 432         struct nf_conn *ct;
 433         struct nf_conn_help *help;
 434         enum ip_conntrack_info ctinfo;
 435
 436         ct = nf_ct_get(*pskb, &ctinfo);
 437
 438         /* ipt_REJECT uses nf_conntrack_attach to attach related
 439            ICMP/TCP RST packets in other direction.  Actual packet
 440            which created connection will be IP_CT_NEW or for an
 441            expected connection, IP_CT_RELATED. */
 442         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 443                 return NF_ACCEPT;
 444
 445         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 446         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 447
 448         /* We're not in hash table, and we refuse to set up related
 449            connections for unconfirmed conns.  But packet copies and
 450            REJECT will give spurious warnings here. */
 451         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 452
 453         /* No external references means noone else could have
 454            confirmed us. */
 455         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 456         DEBUGP("Confirming conntrack %p\n", ct);
 457
 458         write_lock_bh(&nf_conntrack_lock);
 459
 460         /* See if there's one in the list already, including reverse:
 461            NAT could have grabbed it without realizing, since we're
 462            not in the hash.  If there is, we lost race. */
 463         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
 464                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 465                                       &h->tuple))
 466                         goto out;
 467         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
 468                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 469                                       &h->tuple))
 470                         goto out;
 471
 472         /* Remove from unconfirmed list */
 473         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 474
 475         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 476         /* Timer relative to confirmation time, not original
 477            setting time, otherwise we'd get timer wrap in
 478            weird delay cases. */
 479         ct->timeout.expires += jiffies;
 480         add_timer(&ct->timeout);
 481         atomic_inc(&ct->ct_general.use);
 482         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 483         NF_CT_STAT_INC(insert);
 484         write_unlock_bh(&nf_conntrack_lock);
 485         help = nfct_help(ct);
 486         if (help && help->helper)
 487                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 488 #ifdef CONFIG_NF_NAT_NEEDED
 489         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 490             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 491                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 492 #endif
 493         nf_conntrack_event_cache(master_ct(ct) ?
 494                                  IPCT_RELATED : IPCT_NEW, *pskb);
 495         return NF_ACCEPT;
 496
 497 out:
 498         NF_CT_STAT_INC(insert_failed);
 499         write_unlock_bh(&nf_conntrack_lock);
 500         return NF_DROP;
 501 }
 502
 503 /* Returns true if a connection correspondings to the tuple (required
 504    for NAT). */
 505 int
 506 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 507                          const struct nf_conn *ignored_conntrack)
 508 {
 509         struct nf_conntrack_tuple_hash *h;
 510
 511         read_lock_bh(&nf_conntrack_lock);
 512         h = __nf_conntrack_find(tuple, ignored_conntrack);
 513         read_unlock_bh(&nf_conntrack_lock);
 514
 515         return h != NULL;
 516 }
 517
 518 /* There's a small race here where we may free a just-assured
 519    connection.  Too bad: we're in trouble anyway. */
 520 static int early_drop(struct list_head *chain)
 521 {
 522         /* Traverse backwards: gives us oldest, which is roughly LRU */
 523         struct nf_conntrack_tuple_hash *h;
 524         struct nf_conn *ct = NULL, *tmp;
 525         int dropped = 0;
 526
 527         read_lock_bh(&nf_conntrack_lock);
 528         list_for_each_entry_reverse(h, chain, list) {
 529                 tmp = nf_ct_tuplehash_to_ctrack(h);
 530                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
 531                         ct = tmp;
 532                         atomic_inc(&ct->ct_general.use);
 533                         break;
 534                 }
 535         }
 536         read_unlock_bh(&nf_conntrack_lock);
 537
 538         if (!ct)
 539                 return dropped;
 540
 541         if (del_timer(&ct->timeout)) {
 542                 death_by_timeout((unsigned long)ct);
 543                 dropped = 1;
 544                 NF_CT_STAT_INC(early_drop);
 545         }
 546         nf_ct_put(ct);
 547         return dropped;
 548 }
 549
 550 static struct nf_conn *
 551 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 552                      const struct nf_conntrack_tuple *repl,
 553                      const struct nf_conntrack_l3proto *l3proto)
 554 {
 555         struct nf_conn *conntrack = NULL;
 556         u_int32_t features = 0;
 557         struct nf_conntrack_helper *helper;
 558
 559         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 560                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 561                 nf_conntrack_hash_rnd_initted = 1;
 562         }
 563
 564         /* We don't want any race condition at early drop stage */
 565         atomic_inc(&nf_conntrack_count);
 566
 567         if (nf_conntrack_max
 568             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 569                 unsigned int hash = hash_conntrack(orig);
 570                 /* Try dropping from this hash chain. */
 571                 if (!early_drop(&nf_conntrack_hash[hash])) {
 572                         atomic_dec(&nf_conntrack_count);
 573                         if (net_ratelimit())
 574                                 printk(KERN_WARNING
 575                                        "nf_conntrack: table full, dropping"
 576                                        " packet.\n");
 577                         return ERR_PTR(-ENOMEM);
 578                 }
 579         }
 580
 581         /*  find features needed by this conntrack. */
 582         features = l3proto->get_features(orig);
 583
 584         /* FIXME: protect helper list per RCU */
 585         read_lock_bh(&nf_conntrack_lock);
 586         helper = __nf_ct_helper_find(repl);
 587         if (helper)
 588                 features |= NF_CT_F_HELP;
 589         read_unlock_bh(&nf_conntrack_lock);
 590
 591         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 592
 593         read_lock_bh(&nf_ct_cache_lock);
 594
 595         if (unlikely(!nf_ct_cache[features].use)) {
 596                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
 597                         features);
 598                 goto out;
 599         }
 600
 601         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
 602         if (conntrack == NULL) {
 603                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
 604                 goto out;
 605         }
 606
 607         memset(conntrack, 0, nf_ct_cache[features].size);
 608         conntrack->features = features;
 609         atomic_set(&conntrack->ct_general.use, 1);
 610         conntrack->ct_general.destroy = destroy_conntrack;
 611         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 612         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 613         /* Don't set timer yet: wait for confirmation */
 614         init_timer(&conntrack->timeout);
 615         conntrack->timeout.data = (unsigned long)conntrack;
 616         conntrack->timeout.function = death_by_timeout;
 617         read_unlock_bh(&nf_ct_cache_lock);
 618
 619         return conntrack;
 620 out:
 621         read_unlock_bh(&nf_ct_cache_lock);
 622         atomic_dec(&nf_conntrack_count);
 623         return conntrack;
 624 }
 625
 626 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 627                                    const struct nf_conntrack_tuple *repl)
 628 {
 629         struct nf_conntrack_l3proto *l3proto;
 630
 631         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
 632         return __nf_conntrack_alloc(orig, repl, l3proto);
 633 }
 634
 635 void nf_conntrack_free(struct nf_conn *conntrack)
 636 {
 637         u_int32_t features = conntrack->features;
 638         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
 639         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
 640                conntrack);
 641         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
 642         atomic_dec(&nf_conntrack_count);
 643 }
 644
 645 /* Allocate a new conntrack: we return -ENOMEM if classification
 646    failed due to stress.  Otherwise it really is unclassifiable. */
 647 static struct nf_conntrack_tuple_hash *
 648 init_conntrack(const struct nf_conntrack_tuple *tuple,
 649                struct nf_conntrack_l3proto *l3proto,
 650                struct nf_conntrack_protocol *protocol,
 651                struct sk_buff *skb,
 652                unsigned int dataoff)
 653 {
 654         struct nf_conn *conntrack;
 655         struct nf_conntrack_tuple repl_tuple;
 656         struct nf_conntrack_expect *exp;
 657
 658         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, protocol)) {
 659                 DEBUGP("Can't invert tuple.\n");
 660                 return NULL;
 661         }
 662
 663         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto);
 664         if (conntrack == NULL || IS_ERR(conntrack)) {
 665                 DEBUGP("Can't allocate conntrack.\n");
 666                 return (struct nf_conntrack_tuple_hash *)conntrack;
 667         }
 668
 669         if (!protocol->new(conntrack, skb, dataoff)) {
 670                 nf_conntrack_free(conntrack);
 671                 DEBUGP("init conntrack: can't track with proto module\n");
 672                 return NULL;
 673         }
 674
 675         write_lock_bh(&nf_conntrack_lock);
 676         exp = find_expectation(tuple);
 677
 678         if (exp) {
 679                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 680                         conntrack, exp);
 681                 /* Welcome, Mr. Bond.  We've been expecting you... */
 682                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 683                 conntrack->master = exp->master;
 684 #ifdef CONFIG_NF_CONNTRACK_MARK
 685                 conntrack->mark = exp->master->mark;
 686 #endif
 687 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 688                 conntrack->secmark = exp->master->secmark;
 689 #endif
 690                 nf_conntrack_get(&conntrack->master->ct_general);
 691                 NF_CT_STAT_INC(expect_new);
 692         } else {
 693                 struct nf_conn_help *help = nfct_help(conntrack);
 694
 695                 if (help)
 696                         help->helper = __nf_ct_helper_find(&repl_tuple);
 697                 NF_CT_STAT_INC(new);
 698         }
 699
 700         /* Overload tuple linked list to put us in unconfirmed list. */
 701         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 702
 703         write_unlock_bh(&nf_conntrack_lock);
 704
 705         if (exp) {
 706                 if (exp->expectfn)
 707                         exp->expectfn(conntrack, exp);
 708                 nf_conntrack_expect_put(exp);
 709         }
 710
 711         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 712 }
 713
 714 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 715 static inline struct nf_conn *
 716 resolve_normal_ct(struct sk_buff *skb,
 717                   unsigned int dataoff,
 718                   u_int16_t l3num,
 719                   u_int8_t protonum,
 720                   struct nf_conntrack_l3proto *l3proto,
 721                   struct nf_conntrack_protocol *proto,
 722                   int *set_reply,
 723                   enum ip_conntrack_info *ctinfo)
 724 {
 725         struct nf_conntrack_tuple tuple;
 726         struct nf_conntrack_tuple_hash *h;
 727         struct nf_conn *ct;
 728
 729         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
 730                              dataoff, l3num, protonum, &tuple, l3proto,
 731                              proto)) {
 732                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
 733                 return NULL;
 734         }
 735
 736         /* look for tuple match */
 737         h = nf_conntrack_find_get(&tuple, NULL);
 738         if (!h) {
 739                 h = init_conntrack(&tuple, l3proto, proto, skb, dataoff);
 740                 if (!h)
 741                         return NULL;
 742                 if (IS_ERR(h))
 743                         return (void *)h;
 744         }
 745         ct = nf_ct_tuplehash_to_ctrack(h);
 746
 747         /* It exists; we have (non-exclusive) reference. */
 748         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 749                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 750                 /* Please set reply bit if this packet OK */
 751                 *set_reply = 1;
 752         } else {
 753                 /* Once we've had two way comms, always ESTABLISHED. */
 754                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 755                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
 756                         *ctinfo = IP_CT_ESTABLISHED;
 757                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 758                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
 759                         *ctinfo = IP_CT_RELATED;
 760                 } else {
 761                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
 762                         *ctinfo = IP_CT_NEW;
 763                 }
 764                 *set_reply = 0;
 765         }
 766         skb->nfct = &ct->ct_general;
 767         skb->nfctinfo = *ctinfo;
 768         return ct;
 769 }
 770
 771 unsigned int
 772 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 773 {
 774         struct nf_conn *ct;
 775         enum ip_conntrack_info ctinfo;
 776         struct nf_conntrack_l3proto *l3proto;
 777         struct nf_conntrack_protocol *proto;
 778         unsigned int dataoff;
 779         u_int8_t protonum;
 780         int set_reply = 0;
 781         int ret;
 782
 783         /* Previously seen (loopback or untracked)?  Ignore. */
 784         if ((*pskb)->nfct) {
 785                 NF_CT_STAT_INC(ignore);
 786                 return NF_ACCEPT;
 787         }
 788
 789         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 790         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
 791                 DEBUGP("not prepared to track yet or error occured\n");
 792                 return -ret;
 793         }
 794
 795         proto = __nf_ct_proto_find((u_int16_t)pf, protonum);
 796
 797         /* It may be an special packet, error, unclean...
 798          * inverse of the return code tells to the netfilter
 799          * core what to do with the packet. */
 800         if (proto->error != NULL &&
 801             (ret = proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 802                 NF_CT_STAT_INC(error);
 803                 NF_CT_STAT_INC(invalid);
 804                 return -ret;
 805         }
 806
 807         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, proto,
 808                                &set_reply, &ctinfo);
 809         if (!ct) {
 810                 /* Not valid part of a connection */
 811                 NF_CT_STAT_INC(invalid);
 812                 return NF_ACCEPT;
 813         }
 814
 815         if (IS_ERR(ct)) {
 816                 /* Too stressed to deal. */
 817                 NF_CT_STAT_INC(drop);
 818                 return NF_DROP;
 819         }
 820
 821         NF_CT_ASSERT((*pskb)->nfct);
 822
 823         ret = proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
 824         if (ret < 0) {
 825                 /* Invalid: inverse of the return code tells
 826                  * the netfilter core what to do */
 827                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
 828                 nf_conntrack_put((*pskb)->nfct);
 829                 (*pskb)->nfct = NULL;
 830                 NF_CT_STAT_INC(invalid);
 831                 return -ret;
 832         }
 833
 834         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 835                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
 836
 837         return ret;
 838 }
 839
 840 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 841                          const struct nf_conntrack_tuple *orig)
 842 {
 843         return nf_ct_invert_tuple(inverse, orig,
 844                                   __nf_ct_l3proto_find(orig->src.l3num),
 845                                   __nf_ct_proto_find(orig->src.l3num,
 846                                                      orig->dst.protonum));
 847 }
 848
 849 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 850 void __nf_ct_refresh_acct(struct nf_conn *ct,
 851                           enum ip_conntrack_info ctinfo,
 852                           const struct sk_buff *skb,
 853                           unsigned long extra_jiffies,
 854                           int do_acct)
 855 {
 856         int event = 0;
 857
 858         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 859         NF_CT_ASSERT(skb);
 860
 861         write_lock_bh(&nf_conntrack_lock);
 862
 863         /* Only update if this is not a fixed timeout */
 864         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 865                 write_unlock_bh(&nf_conntrack_lock);
 866                 return;
 867         }
 868
 869         /* If not in hash table, timer will not be active yet */
 870         if (!nf_ct_is_confirmed(ct)) {
 871                 ct->timeout.expires = extra_jiffies;
 872                 event = IPCT_REFRESH;
 873         } else {
 874                 /* Need del_timer for race avoidance (may already be dying). */
 875                 if (del_timer(&ct->timeout)) {
 876                         ct->timeout.expires = jiffies + extra_jiffies;
 877                         add_timer(&ct->timeout);
 878                         event = IPCT_REFRESH;
 879                 }
 880         }
 881
 882 #ifdef CONFIG_NF_CT_ACCT
 883         if (do_acct) {
 884                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 885                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 886                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
 887         if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 888             || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 889                 event |= IPCT_COUNTER_FILLING;
 890         }
 891 #endif
 892
 893         write_unlock_bh(&nf_conntrack_lock);
 894
 895         /* must be unlocked when calling event cache */
 896         if (event)
 897                 nf_conntrack_event_cache(event, skb);
 898 }
 899
 900 #if defined(CONFIG_NF_CT_NETLINK) || \
 901     defined(CONFIG_NF_CT_NETLINK_MODULE)
 902
 903 #include <linux/netfilter/nfnetlink.h>
 904 #include <linux/netfilter/nfnetlink_conntrack.h>
 905 #include <linux/mutex.h>
 906
 907
 908 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 909  * in ip_conntrack_core, since we don't want the protocols to autoload
 910  * or depend on ctnetlink */
 911 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
 912                                const struct nf_conntrack_tuple *tuple)
 913 {
 914         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
 915                 &tuple->src.u.tcp.port);
 916         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
 917                 &tuple->dst.u.tcp.port);
 918         return 0;
 919
 920 nfattr_failure:
 921         return -1;
 922 }
 923
 924 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
 925         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
 926         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
 927 };
 928
 929 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
 930                                struct nf_conntrack_tuple *t)
 931 {
 932         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
 933                 return -EINVAL;
 934
 935         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
 936                 return -EINVAL;
 937
 938         t->src.u.tcp.port =
 939                 *(u_int16_t *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
 940         t->dst.u.tcp.port =
 941                 *(u_int16_t *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
 942
 943         return 0;
 944 }
 945 #endif
 946
 947 /* Used by ipt_REJECT and ip6t_REJECT. */
 948 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
 949 {
 950         struct nf_conn *ct;
 951         enum ip_conntrack_info ctinfo;
 952
 953         /* This ICMP is in reverse direction to the packet which caused it */
 954         ct = nf_ct_get(skb, &ctinfo);
 955         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
 956                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
 957         else
 958                 ctinfo = IP_CT_RELATED;
 959
 960         /* Attach to new skbuff, and increment count */
 961         nskb->nfct = &ct->ct_general;
 962         nskb->nfctinfo = ctinfo;
 963         nf_conntrack_get(nskb->nfct);
 964 }
 965
 966 static inline int
 967 do_iter(const struct nf_conntrack_tuple_hash *i,
 968         int (*iter)(struct nf_conn *i, void *data),
 969         void *data)
 970 {
 971         return iter(nf_ct_tuplehash_to_ctrack(i), data);
 972 }
 973
 974 /* Bring out ya dead! */
 975 static struct nf_conn *
 976 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
 977                 void *data, unsigned int *bucket)
 978 {
 979         struct nf_conntrack_tuple_hash *h;
 980         struct nf_conn *ct;
 981
 982         write_lock_bh(&nf_conntrack_lock);
 983         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
 984                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
 985                         ct = nf_ct_tuplehash_to_ctrack(h);
 986                         if (iter(ct, data))
 987                                 goto found;
 988                 }
 989         }
 990         list_for_each_entry(h, &unconfirmed, list) {
 991                 ct = nf_ct_tuplehash_to_ctrack(h);
 992                 if (iter(ct, data))
 993                         goto found;
 994         }
 995         write_unlock_bh(&nf_conntrack_lock);
 996         return NULL;
 997 found:
 998         atomic_inc(&ct->ct_general.use);
 999         write_unlock_bh(&nf_conntrack_lock);
1000         return ct;
1001 }
1002
1003 void
1004 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1005 {
1006         struct nf_conn *ct;
1007         unsigned int bucket = 0;
1008
1009         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1010                 /* Time to push up daises... */
1011                 if (del_timer(&ct->timeout))
1012                         death_by_timeout((unsigned long)ct);
1013                 /* ... else the timer will get him soon. */
1014
1015                 nf_ct_put(ct);
1016         }
1017 }
1018
1019 static int kill_all(struct nf_conn *i, void *data)
1020 {
1021         return 1;
1022 }
1023
1024 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1025 {
1026         if (vmalloced)
1027                 vfree(hash);
1028         else
1029                 free_pages((unsigned long)hash,
1030                            get_order(sizeof(struct list_head) * size));
1031 }
1032
1033 void nf_conntrack_flush()
1034 {
1035         nf_ct_iterate_cleanup(kill_all, NULL);
1036 }
1037
1038 /* Mishearing the voices in his head, our hero wonders how he's
1039    supposed to kill the mall. */
1040 void nf_conntrack_cleanup(void)
1041 {
1042         int i;
1043
1044         ip_ct_attach = NULL;
1045
1046         /* This makes sure all current packets have passed through
1047            netfilter framework.  Roll on, two-stage module
1048            delete... */
1049         synchronize_net();
1050
1051         nf_ct_event_cache_flush();
1052  i_see_dead_people:
1053         nf_conntrack_flush();
1054         if (atomic_read(&nf_conntrack_count) != 0) {
1055                 schedule();
1056                 goto i_see_dead_people;
1057         }
1058         /* wait until all references to nf_conntrack_untracked are dropped */
1059         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1060                 schedule();
1061
1062         for (i = 0; i < NF_CT_F_NUM; i++) {
1063                 if (nf_ct_cache[i].use == 0)
1064                         continue;
1065
1066                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1067                 nf_ct_cache[i].use = 1;
1068                 nf_conntrack_unregister_cache(i);
1069         }
1070         kmem_cache_destroy(nf_conntrack_expect_cachep);
1071         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1072                             nf_conntrack_htable_size);
1073
1074         /* free l3proto protocol tables */
1075         for (i = 0; i < PF_MAX; i++)
1076                 if (nf_ct_protos[i]) {
1077                         kfree(nf_ct_protos[i]);
1078                         nf_ct_protos[i] = NULL;
1079                 }
1080 }
1081
1082 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1083 {
1084         struct list_head *hash;
1085         unsigned int i;
1086
1087         *vmalloced = 0;
1088         hash = (void*)__get_free_pages(GFP_KERNEL,
1089                                        get_order(sizeof(struct list_head)
1090                                                  * size));
1091         if (!hash) {
1092                 *vmalloced = 1;
1093                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1094                 hash = vmalloc(sizeof(struct list_head) * size);
1095         }
1096
1097         if (hash)
1098                 for (i = 0; i < size; i++)
1099                         INIT_LIST_HEAD(&hash[i]);
1100
1101         return hash;
1102 }
1103
1104 int set_hashsize(const char *val, struct kernel_param *kp)
1105 {
1106         int i, bucket, hashsize, vmalloced;
1107         int old_vmalloced, old_size;
1108         int rnd;
1109         struct list_head *hash, *old_hash;
1110         struct nf_conntrack_tuple_hash *h;
1111
1112         /* On boot, we can set this without any fancy locking. */
1113         if (!nf_conntrack_htable_size)
1114                 return param_set_uint(val, kp);
1115
1116         hashsize = simple_strtol(val, NULL, 0);
1117         if (!hashsize)
1118                 return -EINVAL;
1119
1120         hash = alloc_hashtable(hashsize, &vmalloced);
1121         if (!hash)
1122                 return -ENOMEM;
1123
1124         /* We have to rehahs for the new table anyway, so we also can
1125          * use a newrandom seed */
1126         get_random_bytes(&rnd, 4);
1127
1128         write_lock_bh(&nf_conntrack_lock);
1129         for (i = 0; i < nf_conntrack_htable_size; i++) {
1130                 while (!list_empty(&nf_conntrack_hash[i])) {
1131                         h = list_entry(nf_conntrack_hash[i].next,
1132                                        struct nf_conntrack_tuple_hash, list);
1133                         list_del(&h->list);
1134                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1135                         list_add_tail(&h->list, &hash[bucket]);
1136                 }
1137         }
1138         old_size = nf_conntrack_htable_size;
1139         old_vmalloced = nf_conntrack_vmalloc;
1140         old_hash = nf_conntrack_hash;
1141
1142         nf_conntrack_htable_size = hashsize;
1143         nf_conntrack_vmalloc = vmalloced;
1144         nf_conntrack_hash = hash;
1145         nf_conntrack_hash_rnd = rnd;
1146         write_unlock_bh(&nf_conntrack_lock);
1147
1148         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1149         return 0;
1150 }
1151
1152 module_param_call(hashsize, set_hashsize, param_get_uint,
1153                   &nf_conntrack_htable_size, 0600);
1154
1155 int __init nf_conntrack_init(void)
1156 {
1157         unsigned int i;
1158         int ret;
1159
1160         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1161          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1162         if (!nf_conntrack_htable_size) {
1163                 nf_conntrack_htable_size
1164                         = (((num_physpages << PAGE_SHIFT) / 16384)
1165                            / sizeof(struct list_head));
1166                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1167                         nf_conntrack_htable_size = 8192;
1168                 if (nf_conntrack_htable_size < 16)
1169                         nf_conntrack_htable_size = 16;
1170         }
1171         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1172
1173         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1174                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1175                nf_conntrack_max);
1176
1177         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1178                                             &nf_conntrack_vmalloc);
1179         if (!nf_conntrack_hash) {
1180                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1181                 goto err_out;
1182         }
1183
1184         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1185                                           sizeof(struct nf_conn));
1186         if (ret < 0) {
1187                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1188                 goto err_free_hash;
1189         }
1190
1191         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1192                                         sizeof(struct nf_conntrack_expect),
1193                                         0, 0, NULL, NULL);
1194         if (!nf_conntrack_expect_cachep) {
1195                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1196                 goto err_free_conntrack_slab;
1197         }
1198
1199         /* Don't NEED lock here, but good form anyway. */
1200         write_lock_bh(&nf_conntrack_lock);
1201         for (i = 0; i < PF_MAX; i++)
1202                 nf_ct_l3protos[i] = &nf_conntrack_generic_l3proto;
1203         write_unlock_bh(&nf_conntrack_lock);
1204
1205         /* For use by REJECT target */
1206         ip_ct_attach = __nf_conntrack_attach;
1207
1208         /* Set up fake conntrack:
1209             - to never be deleted, not in any hashes */
1210         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1211         /*  - and look it like as a confirmed connection */
1212         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1213
1214         return ret;
1215
1216 err_free_conntrack_slab:
1217         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1218 err_free_hash:
1219         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1220                             nf_conntrack_htable_size);
1221 err_out:
1222         return -ENOMEM;
1223 }