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