git.oblomov.eu Git - linux-2.6/blob - net/netfilter/nf_conntrack_core.c

   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
  14  *      - new API and handling of conntrack/nat helpers
  15  *      - now capable of multiple expectations for one master
  16  * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
  17  *      - add usage/reference counts to ip_conntrack_expect
  18  *      - export ip_conntrack[_expect]_{find_get,put} functions
  19  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  20  *      - generalize L3 protocol denendent part.
  21  * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  22  *      - add support various size of conntrack structures.
  23  * 26 Jan 2006: Harald Welte <laforge@netfilter.org>
  24  *      - restructure nf_conn (introduce nf_conn_help)
  25  *      - redesign 'features' how they were originally intended
  26  * 26 Feb 2006: Pablo Neira Ayuso <pablo@eurodev.net>
  27  *      - add support for L3 protocol module load on demand.
  28  *
  29  * Derived from net/ipv4/netfilter/ip_conntrack_core.c
  30  */
  31
  32 #include <linux/types.h>
  33 #include <linux/netfilter.h>
  34 #include <linux/module.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/vmalloc.h>
  38 #include <linux/stddef.h>
  39 #include <linux/slab.h>
  40 #include <linux/random.h>
  41 #include <linux/jhash.h>
  42 #include <linux/err.h>
  43 #include <linux/percpu.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/notifier.h>
  46 #include <linux/kernel.h>
  47 #include <linux/netdevice.h>
  48 #include <linux/socket.h>
  49 #include <linux/mm.h>
  50
  51 #include <net/netfilter/nf_conntrack.h>
  52 #include <net/netfilter/nf_conntrack_l3proto.h>
  53 #include <net/netfilter/nf_conntrack_l4proto.h>
  54 #include <net/netfilter/nf_conntrack_expect.h>
  55 #include <net/netfilter/nf_conntrack_helper.h>
  56 #include <net/netfilter/nf_conntrack_core.h>
  57
  58 #define NF_CONNTRACK_VERSION    "0.5.0"
  59
  60 #if 0
  61 #define DEBUGP printk
  62 #else
  63 #define DEBUGP(format, args...)
  64 #endif
  65
  66 DEFINE_RWLOCK(nf_conntrack_lock);
  67 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  68
  69 /* nf_conntrack_standalone needs this */
  70 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  71 EXPORT_SYMBOL_GPL(nf_conntrack_count);
  72
  73 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack);
  74 EXPORT_SYMBOL_GPL(nf_conntrack_destroyed);
  75
  76 unsigned int nf_conntrack_htable_size __read_mostly;
  77 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  78
  79 int nf_conntrack_max __read_mostly;
  80 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  81
  82 struct list_head *nf_conntrack_hash __read_mostly;
  83 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  84
  85 struct nf_conn nf_conntrack_untracked __read_mostly;
  86 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
  87
  88 unsigned int nf_ct_log_invalid __read_mostly;
  89 LIST_HEAD(unconfirmed);
  90 static int nf_conntrack_vmalloc __read_mostly;
  91
  92 static unsigned int nf_conntrack_next_id;
  93
  94 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  95 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  96
  97 /*
  98  * This scheme offers various size of "struct nf_conn" dependent on
  99  * features(helper, nat, ...)
 100  */
 101
 102 #define NF_CT_FEATURES_NAMELEN  256
 103 static struct {
 104         /* name of slab cache. printed in /proc/slabinfo */
 105         char *name;
 106
 107         /* size of slab cache */
 108         size_t size;
 109
 110         /* slab cache pointer */
 111         struct kmem_cache *cachep;
 112
 113         /* allocated slab cache + modules which uses this slab cache */
 114         int use;
 115
 116 } nf_ct_cache[NF_CT_F_NUM];
 117
 118 /* protect members of nf_ct_cache except of "use" */
 119 DEFINE_RWLOCK(nf_ct_cache_lock);
 120
 121 /* This avoids calling kmem_cache_create() with same name simultaneously */
 122 static DEFINE_MUTEX(nf_ct_cache_mutex);
 123
 124 static int nf_conntrack_hash_rnd_initted;
 125 static unsigned int nf_conntrack_hash_rnd;
 126
 127 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 128                                   unsigned int size, unsigned int rnd)
 129 {
 130         unsigned int a, b;
 131         a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
 132                   ((tuple->src.l3num) << 16) | tuple->dst.protonum);
 133         b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
 134                         (tuple->src.u.all << 16) | tuple->dst.u.all);
 135
 136         return jhash_2words(a, b, rnd) % size;
 137 }
 138
 139 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
 140 {
 141         return __hash_conntrack(tuple, nf_conntrack_htable_size,
 142                                 nf_conntrack_hash_rnd);
 143 }
 144
 145 int nf_conntrack_register_cache(u_int32_t features, const char *name,
 146                                 size_t size)
 147 {
 148         int ret = 0;
 149         char *cache_name;
 150         struct kmem_cache *cachep;
 151
 152         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
 153                features, name, size);
 154
 155         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
 156                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
 157                         features);
 158                 return -EINVAL;
 159         }
 160
 161         mutex_lock(&nf_ct_cache_mutex);
 162
 163         write_lock_bh(&nf_ct_cache_lock);
 164         /* e.g: multiple helpers are loaded */
 165         if (nf_ct_cache[features].use > 0) {
 166                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
 167                 if ((!strncmp(nf_ct_cache[features].name, name,
 168                               NF_CT_FEATURES_NAMELEN))
 169                     && nf_ct_cache[features].size == size) {
 170                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
 171                         nf_ct_cache[features].use++;
 172                         ret = 0;
 173                 } else
 174                         ret = -EBUSY;
 175
 176                 write_unlock_bh(&nf_ct_cache_lock);
 177                 mutex_unlock(&nf_ct_cache_mutex);
 178                 return ret;
 179         }
 180         write_unlock_bh(&nf_ct_cache_lock);
 181
 182         /*
 183          * The memory space for name of slab cache must be alive until
 184          * cache is destroyed.
 185          */
 186         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
 187         if (cache_name == NULL) {
 188                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
 189                 ret = -ENOMEM;
 190                 goto out_up_mutex;
 191         }
 192
 193         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
 194                                                 >= NF_CT_FEATURES_NAMELEN) {
 195                 printk("nf_conntrack_register_cache: name too long\n");
 196                 ret = -EINVAL;
 197                 goto out_free_name;
 198         }
 199
 200         cachep = kmem_cache_create(cache_name, size, 0, 0,
 201                                    NULL, NULL);
 202         if (!cachep) {
 203                 printk("nf_conntrack_register_cache: Can't create slab cache "
 204                        "for the features = 0x%x\n", features);
 205                 ret = -ENOMEM;
 206                 goto out_free_name;
 207         }
 208
 209         write_lock_bh(&nf_ct_cache_lock);
 210         nf_ct_cache[features].use = 1;
 211         nf_ct_cache[features].size = size;
 212         nf_ct_cache[features].cachep = cachep;
 213         nf_ct_cache[features].name = cache_name;
 214         write_unlock_bh(&nf_ct_cache_lock);
 215
 216         goto out_up_mutex;
 217
 218 out_free_name:
 219         kfree(cache_name);
 220 out_up_mutex:
 221         mutex_unlock(&nf_ct_cache_mutex);
 222         return ret;
 223 }
 224 EXPORT_SYMBOL_GPL(nf_conntrack_register_cache);
 225
 226 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
 227 void nf_conntrack_unregister_cache(u_int32_t features)
 228 {
 229         struct kmem_cache *cachep;
 230         char *name;
 231
 232         /*
 233          * This assures that kmem_cache_create() isn't called before destroying
 234          * slab cache.
 235          */
 236         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
 237         mutex_lock(&nf_ct_cache_mutex);
 238
 239         write_lock_bh(&nf_ct_cache_lock);
 240         if (--nf_ct_cache[features].use > 0) {
 241                 write_unlock_bh(&nf_ct_cache_lock);
 242                 mutex_unlock(&nf_ct_cache_mutex);
 243                 return;
 244         }
 245         cachep = nf_ct_cache[features].cachep;
 246         name = nf_ct_cache[features].name;
 247         nf_ct_cache[features].cachep = NULL;
 248         nf_ct_cache[features].name = NULL;
 249         nf_ct_cache[features].size = 0;
 250         write_unlock_bh(&nf_ct_cache_lock);
 251
 252         synchronize_net();
 253
 254         kmem_cache_destroy(cachep);
 255         kfree(name);
 256
 257         mutex_unlock(&nf_ct_cache_mutex);
 258 }
 259 EXPORT_SYMBOL_GPL(nf_conntrack_unregister_cache);
 260
 261 int
 262 nf_ct_get_tuple(const struct sk_buff *skb,
 263                 unsigned int nhoff,
 264                 unsigned int dataoff,
 265                 u_int16_t l3num,
 266                 u_int8_t protonum,
 267                 struct nf_conntrack_tuple *tuple,
 268                 const struct nf_conntrack_l3proto *l3proto,
 269                 const struct nf_conntrack_l4proto *l4proto)
 270 {
 271         NF_CT_TUPLE_U_BLANK(tuple);
 272
 273         tuple->src.l3num = l3num;
 274         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 275                 return 0;
 276
 277         tuple->dst.protonum = protonum;
 278         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 279
 280         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 281 }
 282 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 283
 284 int
 285 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 286                    const struct nf_conntrack_tuple *orig,
 287                    const struct nf_conntrack_l3proto *l3proto,
 288                    const struct nf_conntrack_l4proto *l4proto)
 289 {
 290         NF_CT_TUPLE_U_BLANK(inverse);
 291
 292         inverse->src.l3num = orig->src.l3num;
 293         if (l3proto->invert_tuple(inverse, orig) == 0)
 294                 return 0;
 295
 296         inverse->dst.dir = !orig->dst.dir;
 297
 298         inverse->dst.protonum = orig->dst.protonum;
 299         return l4proto->invert_tuple(inverse, orig);
 300 }
 301 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 302
 303 static void
 304 clean_from_lists(struct nf_conn *ct)
 305 {
 306         DEBUGP("clean_from_lists(%p)\n", ct);
 307         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 308         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
 309
 310         /* Destroy all pending expectations */
 311         nf_ct_remove_expectations(ct);
 312 }
 313
 314 static void
 315 destroy_conntrack(struct nf_conntrack *nfct)
 316 {
 317         struct nf_conn *ct = (struct nf_conn *)nfct;
 318         struct nf_conn_help *help = nfct_help(ct);
 319         struct nf_conntrack_l3proto *l3proto;
 320         struct nf_conntrack_l4proto *l4proto;
 321
 322         DEBUGP("destroy_conntrack(%p)\n", ct);
 323         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 324         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 325
 326         nf_conntrack_event(IPCT_DESTROY, ct);
 327         set_bit(IPS_DYING_BIT, &ct->status);
 328
 329         if (help && help->helper && help->helper->destroy)
 330                 help->helper->destroy(ct);
 331
 332         /* To make sure we don't get any weird locking issues here:
 333          * destroy_conntrack() MUST NOT be called with a write lock
 334          * to nf_conntrack_lock!!! -HW */
 335         rcu_read_lock();
 336         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
 337         if (l3proto && l3proto->destroy)
 338                 l3proto->destroy(ct);
 339
 340         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
 341                                        ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 342         if (l4proto && l4proto->destroy)
 343                 l4proto->destroy(ct);
 344         rcu_read_unlock();
 345
 346         if (nf_conntrack_destroyed)
 347                 nf_conntrack_destroyed(ct);
 348
 349         write_lock_bh(&nf_conntrack_lock);
 350         /* Expectations will have been removed in clean_from_lists,
 351          * except TFTP can create an expectation on the first packet,
 352          * before connection is in the list, so we need to clean here,
 353          * too. */
 354         nf_ct_remove_expectations(ct);
 355
 356         /* We overload first tuple to link into unconfirmed list. */
 357         if (!nf_ct_is_confirmed(ct)) {
 358                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 359                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 360         }
 361
 362         NF_CT_STAT_INC(delete);
 363         write_unlock_bh(&nf_conntrack_lock);
 364
 365         if (ct->master)
 366                 nf_ct_put(ct->master);
 367
 368         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 369         nf_conntrack_free(ct);
 370 }
 371
 372 static void death_by_timeout(unsigned long ul_conntrack)
 373 {
 374         struct nf_conn *ct = (void *)ul_conntrack;
 375
 376         write_lock_bh(&nf_conntrack_lock);
 377         /* Inside lock so preempt is disabled on module removal path.
 378          * Otherwise we can get spurious warnings. */
 379         NF_CT_STAT_INC(delete_list);
 380         clean_from_lists(ct);
 381         write_unlock_bh(&nf_conntrack_lock);
 382         nf_ct_put(ct);
 383 }
 384
 385 struct nf_conntrack_tuple_hash *
 386 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 387                     const struct nf_conn *ignored_conntrack)
 388 {
 389         struct nf_conntrack_tuple_hash *h;
 390         unsigned int hash = hash_conntrack(tuple);
 391
 392         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
 393                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 394                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 395                         NF_CT_STAT_INC(found);
 396                         return h;
 397                 }
 398                 NF_CT_STAT_INC(searched);
 399         }
 400
 401         return NULL;
 402 }
 403 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 404
 405 /* Find a connection corresponding to a tuple. */
 406 struct nf_conntrack_tuple_hash *
 407 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
 408                       const struct nf_conn *ignored_conntrack)
 409 {
 410         struct nf_conntrack_tuple_hash *h;
 411
 412         read_lock_bh(&nf_conntrack_lock);
 413         h = __nf_conntrack_find(tuple, ignored_conntrack);
 414         if (h)
 415                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 416         read_unlock_bh(&nf_conntrack_lock);
 417
 418         return h;
 419 }
 420 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 421
 422 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 423                                        unsigned int hash,
 424                                        unsigned int repl_hash)
 425 {
 426         ct->id = ++nf_conntrack_next_id;
 427         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
 428                  &nf_conntrack_hash[hash]);
 429         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
 430                  &nf_conntrack_hash[repl_hash]);
 431 }
 432
 433 void nf_conntrack_hash_insert(struct nf_conn *ct)
 434 {
 435         unsigned int hash, repl_hash;
 436
 437         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 438         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 439
 440         write_lock_bh(&nf_conntrack_lock);
 441         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 442         write_unlock_bh(&nf_conntrack_lock);
 443 }
 444 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 445
 446 /* Confirm a connection given skb; places it in hash table */
 447 int
 448 __nf_conntrack_confirm(struct sk_buff **pskb)
 449 {
 450         unsigned int hash, repl_hash;
 451         struct nf_conntrack_tuple_hash *h;
 452         struct nf_conn *ct;
 453         struct nf_conn_help *help;
 454         enum ip_conntrack_info ctinfo;
 455
 456         ct = nf_ct_get(*pskb, &ctinfo);
 457
 458         /* ipt_REJECT uses nf_conntrack_attach to attach related
 459            ICMP/TCP RST packets in other direction.  Actual packet
 460            which created connection will be IP_CT_NEW or for an
 461            expected connection, IP_CT_RELATED. */
 462         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 463                 return NF_ACCEPT;
 464
 465         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 466         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 467
 468         /* We're not in hash table, and we refuse to set up related
 469            connections for unconfirmed conns.  But packet copies and
 470            REJECT will give spurious warnings here. */
 471         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 472
 473         /* No external references means noone else could have
 474            confirmed us. */
 475         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 476         DEBUGP("Confirming conntrack %p\n", ct);
 477
 478         write_lock_bh(&nf_conntrack_lock);
 479
 480         /* See if there's one in the list already, including reverse:
 481            NAT could have grabbed it without realizing, since we're
 482            not in the hash.  If there is, we lost race. */
 483         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
 484                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 485                                       &h->tuple))
 486                         goto out;
 487         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
 488                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 489                                       &h->tuple))
 490                         goto out;
 491
 492         /* Remove from unconfirmed list */
 493         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 494
 495         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 496         /* Timer relative to confirmation time, not original
 497            setting time, otherwise we'd get timer wrap in
 498            weird delay cases. */
 499         ct->timeout.expires += jiffies;
 500         add_timer(&ct->timeout);
 501         atomic_inc(&ct->ct_general.use);
 502         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 503         NF_CT_STAT_INC(insert);
 504         write_unlock_bh(&nf_conntrack_lock);
 505         help = nfct_help(ct);
 506         if (help && help->helper)
 507                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 508 #ifdef CONFIG_NF_NAT_NEEDED
 509         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 510             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 511                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 512 #endif
 513         nf_conntrack_event_cache(master_ct(ct) ?
 514                                  IPCT_RELATED : IPCT_NEW, *pskb);
 515         return NF_ACCEPT;
 516
 517 out:
 518         NF_CT_STAT_INC(insert_failed);
 519         write_unlock_bh(&nf_conntrack_lock);
 520         return NF_DROP;
 521 }
 522 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 523
 524 /* Returns true if a connection correspondings to the tuple (required
 525    for NAT). */
 526 int
 527 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 528                          const struct nf_conn *ignored_conntrack)
 529 {
 530         struct nf_conntrack_tuple_hash *h;
 531
 532         read_lock_bh(&nf_conntrack_lock);
 533         h = __nf_conntrack_find(tuple, ignored_conntrack);
 534         read_unlock_bh(&nf_conntrack_lock);
 535
 536         return h != NULL;
 537 }
 538 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 539
 540 /* There's a small race here where we may free a just-assured
 541    connection.  Too bad: we're in trouble anyway. */
 542 static int early_drop(struct list_head *chain)
 543 {
 544         /* Traverse backwards: gives us oldest, which is roughly LRU */
 545         struct nf_conntrack_tuple_hash *h;
 546         struct nf_conn *ct = NULL, *tmp;
 547         int dropped = 0;
 548
 549         read_lock_bh(&nf_conntrack_lock);
 550         list_for_each_entry_reverse(h, chain, list) {
 551                 tmp = nf_ct_tuplehash_to_ctrack(h);
 552                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
 553                         ct = tmp;
 554                         atomic_inc(&ct->ct_general.use);
 555                         break;
 556                 }
 557         }
 558         read_unlock_bh(&nf_conntrack_lock);
 559
 560         if (!ct)
 561                 return dropped;
 562
 563         if (del_timer(&ct->timeout)) {
 564                 death_by_timeout((unsigned long)ct);
 565                 dropped = 1;
 566                 NF_CT_STAT_INC(early_drop);
 567         }
 568         nf_ct_put(ct);
 569         return dropped;
 570 }
 571
 572 static struct nf_conn *
 573 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 574                      const struct nf_conntrack_tuple *repl,
 575                      const struct nf_conntrack_l3proto *l3proto,
 576                      u_int32_t features)
 577 {
 578         struct nf_conn *conntrack = NULL;
 579         struct nf_conntrack_helper *helper;
 580
 581         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 582                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 583                 nf_conntrack_hash_rnd_initted = 1;
 584         }
 585
 586         /* We don't want any race condition at early drop stage */
 587         atomic_inc(&nf_conntrack_count);
 588
 589         if (nf_conntrack_max
 590             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 591                 unsigned int hash = hash_conntrack(orig);
 592                 /* Try dropping from this hash chain. */
 593                 if (!early_drop(&nf_conntrack_hash[hash])) {
 594                         atomic_dec(&nf_conntrack_count);
 595                         if (net_ratelimit())
 596                                 printk(KERN_WARNING
 597                                        "nf_conntrack: table full, dropping"
 598                                        " packet.\n");
 599                         return ERR_PTR(-ENOMEM);
 600                 }
 601         }
 602
 603         /*  find features needed by this conntrack. */
 604         features |= l3proto->get_features(orig);
 605
 606         /* FIXME: protect helper list per RCU */
 607         read_lock_bh(&nf_conntrack_lock);
 608         helper = __nf_ct_helper_find(repl);
 609         /* NAT might want to assign a helper later */
 610         if (helper || features & NF_CT_F_NAT)
 611                 features |= NF_CT_F_HELP;
 612         read_unlock_bh(&nf_conntrack_lock);
 613
 614         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 615
 616         read_lock_bh(&nf_ct_cache_lock);
 617
 618         if (unlikely(!nf_ct_cache[features].use)) {
 619                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
 620                         features);
 621                 goto out;
 622         }
 623
 624         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
 625         if (conntrack == NULL) {
 626                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
 627                 goto out;
 628         }
 629
 630         memset(conntrack, 0, nf_ct_cache[features].size);
 631         conntrack->features = features;
 632         atomic_set(&conntrack->ct_general.use, 1);
 633         conntrack->ct_general.destroy = destroy_conntrack;
 634         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 635         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 636         /* Don't set timer yet: wait for confirmation */
 637         init_timer(&conntrack->timeout);
 638         conntrack->timeout.data = (unsigned long)conntrack;
 639         conntrack->timeout.function = death_by_timeout;
 640         read_unlock_bh(&nf_ct_cache_lock);
 641
 642         return conntrack;
 643 out:
 644         read_unlock_bh(&nf_ct_cache_lock);
 645         atomic_dec(&nf_conntrack_count);
 646         return conntrack;
 647 }
 648
 649 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 650                                    const struct nf_conntrack_tuple *repl)
 651 {
 652         struct nf_conntrack_l3proto *l3proto;
 653         struct nf_conn *ct;
 654
 655         rcu_read_lock();
 656         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
 657         ct = __nf_conntrack_alloc(orig, repl, l3proto, 0);
 658         rcu_read_unlock();
 659
 660         return ct;
 661 }
 662 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 663
 664 void nf_conntrack_free(struct nf_conn *conntrack)
 665 {
 666         u_int32_t features = conntrack->features;
 667         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
 668         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
 669                conntrack);
 670         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
 671         atomic_dec(&nf_conntrack_count);
 672 }
 673 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 674
 675 /* Allocate a new conntrack: we return -ENOMEM if classification
 676    failed due to stress.  Otherwise it really is unclassifiable. */
 677 static struct nf_conntrack_tuple_hash *
 678 init_conntrack(const struct nf_conntrack_tuple *tuple,
 679                struct nf_conntrack_l3proto *l3proto,
 680                struct nf_conntrack_l4proto *l4proto,
 681                struct sk_buff *skb,
 682                unsigned int dataoff)
 683 {
 684         struct nf_conn *conntrack;
 685         struct nf_conntrack_tuple repl_tuple;
 686         struct nf_conntrack_expect *exp;
 687         u_int32_t features = 0;
 688
 689         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 690                 DEBUGP("Can't invert tuple.\n");
 691                 return NULL;
 692         }
 693
 694         read_lock_bh(&nf_conntrack_lock);
 695         exp = __nf_conntrack_expect_find(tuple);
 696         if (exp && exp->helper)
 697                 features = NF_CT_F_HELP;
 698         read_unlock_bh(&nf_conntrack_lock);
 699
 700         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
 701         if (conntrack == NULL || IS_ERR(conntrack)) {
 702                 DEBUGP("Can't allocate conntrack.\n");
 703                 return (struct nf_conntrack_tuple_hash *)conntrack;
 704         }
 705
 706         if (!l4proto->new(conntrack, skb, dataoff)) {
 707                 nf_conntrack_free(conntrack);
 708                 DEBUGP("init conntrack: can't track with proto module\n");
 709                 return NULL;
 710         }
 711
 712         write_lock_bh(&nf_conntrack_lock);
 713         exp = find_expectation(tuple);
 714
 715         if (exp) {
 716                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 717                         conntrack, exp);
 718                 /* Welcome, Mr. Bond.  We've been expecting you... */
 719                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 720                 conntrack->master = exp->master;
 721                 if (exp->helper)
 722                         nfct_help(conntrack)->helper = exp->helper;
 723 #ifdef CONFIG_NF_CONNTRACK_MARK
 724                 conntrack->mark = exp->master->mark;
 725 #endif
 726 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 727                 conntrack->secmark = exp->master->secmark;
 728 #endif
 729                 nf_conntrack_get(&conntrack->master->ct_general);
 730                 NF_CT_STAT_INC(expect_new);
 731         } else {
 732                 struct nf_conn_help *help = nfct_help(conntrack);
 733
 734                 if (help)
 735                         help->helper = __nf_ct_helper_find(&repl_tuple);
 736                 NF_CT_STAT_INC(new);
 737         }
 738
 739         /* Overload tuple linked list to put us in unconfirmed list. */
 740         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 741
 742         write_unlock_bh(&nf_conntrack_lock);
 743
 744         if (exp) {
 745                 if (exp->expectfn)
 746                         exp->expectfn(conntrack, exp);
 747                 nf_conntrack_expect_put(exp);
 748         }
 749
 750         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 751 }
 752
 753 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 754 static inline struct nf_conn *
 755 resolve_normal_ct(struct sk_buff *skb,
 756                   unsigned int dataoff,
 757                   u_int16_t l3num,
 758                   u_int8_t protonum,
 759                   struct nf_conntrack_l3proto *l3proto,
 760                   struct nf_conntrack_l4proto *l4proto,
 761                   int *set_reply,
 762                   enum ip_conntrack_info *ctinfo)
 763 {
 764         struct nf_conntrack_tuple tuple;
 765         struct nf_conntrack_tuple_hash *h;
 766         struct nf_conn *ct;
 767
 768         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
 769                              dataoff, l3num, protonum, &tuple, l3proto,
 770                              l4proto)) {
 771                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
 772                 return NULL;
 773         }
 774
 775         /* look for tuple match */
 776         h = nf_conntrack_find_get(&tuple, NULL);
 777         if (!h) {
 778                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 779                 if (!h)
 780                         return NULL;
 781                 if (IS_ERR(h))
 782                         return (void *)h;
 783         }
 784         ct = nf_ct_tuplehash_to_ctrack(h);
 785
 786         /* It exists; we have (non-exclusive) reference. */
 787         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 788                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 789                 /* Please set reply bit if this packet OK */
 790                 *set_reply = 1;
 791         } else {
 792                 /* Once we've had two way comms, always ESTABLISHED. */
 793                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 794                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
 795                         *ctinfo = IP_CT_ESTABLISHED;
 796                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 797                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
 798                         *ctinfo = IP_CT_RELATED;
 799                 } else {
 800                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
 801                         *ctinfo = IP_CT_NEW;
 802                 }
 803                 *set_reply = 0;
 804         }
 805         skb->nfct = &ct->ct_general;
 806         skb->nfctinfo = *ctinfo;
 807         return ct;
 808 }
 809
 810 unsigned int
 811 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 812 {
 813         struct nf_conn *ct;
 814         enum ip_conntrack_info ctinfo;
 815         struct nf_conntrack_l3proto *l3proto;
 816         struct nf_conntrack_l4proto *l4proto;
 817         unsigned int dataoff;
 818         u_int8_t protonum;
 819         int set_reply = 0;
 820         int ret;
 821
 822         /* Previously seen (loopback or untracked)?  Ignore. */
 823         if ((*pskb)->nfct) {
 824                 NF_CT_STAT_INC(ignore);
 825                 return NF_ACCEPT;
 826         }
 827
 828         /* rcu_read_lock()ed by nf_hook_slow */
 829         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 830
 831         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
 832                 DEBUGP("not prepared to track yet or error occured\n");
 833                 return -ret;
 834         }
 835
 836         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
 837
 838         /* It may be an special packet, error, unclean...
 839          * inverse of the return code tells to the netfilter
 840          * core what to do with the packet. */
 841         if (l4proto->error != NULL &&
 842             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 843                 NF_CT_STAT_INC(error);
 844                 NF_CT_STAT_INC(invalid);
 845                 return -ret;
 846         }
 847
 848         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
 849                                &set_reply, &ctinfo);
 850         if (!ct) {
 851                 /* Not valid part of a connection */
 852                 NF_CT_STAT_INC(invalid);
 853                 return NF_ACCEPT;
 854         }
 855
 856         if (IS_ERR(ct)) {
 857                 /* Too stressed to deal. */
 858                 NF_CT_STAT_INC(drop);
 859                 return NF_DROP;
 860         }
 861
 862         NF_CT_ASSERT((*pskb)->nfct);
 863
 864         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
 865         if (ret < 0) {
 866                 /* Invalid: inverse of the return code tells
 867                  * the netfilter core what to do */
 868                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
 869                 nf_conntrack_put((*pskb)->nfct);
 870                 (*pskb)->nfct = NULL;
 871                 NF_CT_STAT_INC(invalid);
 872                 return -ret;
 873         }
 874
 875         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 876                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
 877
 878         return ret;
 879 }
 880 EXPORT_SYMBOL_GPL(nf_conntrack_in);
 881
 882 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 883                          const struct nf_conntrack_tuple *orig)
 884 {
 885         int ret;
 886
 887         rcu_read_lock();
 888         ret = nf_ct_invert_tuple(inverse, orig,
 889                                  __nf_ct_l3proto_find(orig->src.l3num),
 890                                  __nf_ct_l4proto_find(orig->src.l3num,
 891                                                       orig->dst.protonum));
 892         rcu_read_unlock();
 893         return ret;
 894 }
 895 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 896
 897 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 898    implicitly racy: see __nf_conntrack_confirm */
 899 void nf_conntrack_alter_reply(struct nf_conn *ct,
 900                               const struct nf_conntrack_tuple *newreply)
 901 {
 902         struct nf_conn_help *help = nfct_help(ct);
 903
 904         write_lock_bh(&nf_conntrack_lock);
 905         /* Should be unconfirmed, so not in hash table yet */
 906         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 907
 908         DEBUGP("Altering reply tuple of %p to ", ct);
 909         NF_CT_DUMP_TUPLE(newreply);
 910
 911         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 912         if (!ct->master && help && help->expecting == 0)
 913                 help->helper = __nf_ct_helper_find(newreply);
 914         write_unlock_bh(&nf_conntrack_lock);
 915 }
 916 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 917
 918 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 919 void __nf_ct_refresh_acct(struct nf_conn *ct,
 920                           enum ip_conntrack_info ctinfo,
 921                           const struct sk_buff *skb,
 922                           unsigned long extra_jiffies,
 923                           int do_acct)
 924 {
 925         int event = 0;
 926
 927         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 928         NF_CT_ASSERT(skb);
 929
 930         write_lock_bh(&nf_conntrack_lock);
 931
 932         /* Only update if this is not a fixed timeout */
 933         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 934                 write_unlock_bh(&nf_conntrack_lock);
 935                 return;
 936         }
 937
 938         /* If not in hash table, timer will not be active yet */
 939         if (!nf_ct_is_confirmed(ct)) {
 940                 ct->timeout.expires = extra_jiffies;
 941                 event = IPCT_REFRESH;
 942         } else {
 943                 unsigned long newtime = jiffies + extra_jiffies;
 944
 945                 /* Only update the timeout if the new timeout is at least
 946                    HZ jiffies from the old timeout. Need del_timer for race
 947                    avoidance (may already be dying). */
 948                 if (newtime - ct->timeout.expires >= HZ
 949                     && del_timer(&ct->timeout)) {
 950                         ct->timeout.expires = newtime;
 951                         add_timer(&ct->timeout);
 952                         event = IPCT_REFRESH;
 953                 }
 954         }
 955
 956 #ifdef CONFIG_NF_CT_ACCT
 957         if (do_acct) {
 958                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 959                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 960                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
 961
 962                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 963                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 964                         event |= IPCT_COUNTER_FILLING;
 965         }
 966 #endif
 967
 968         write_unlock_bh(&nf_conntrack_lock);
 969
 970         /* must be unlocked when calling event cache */
 971         if (event)
 972                 nf_conntrack_event_cache(event, skb);
 973 }
 974 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 975
 976 #if defined(CONFIG_NF_CT_NETLINK) || \
 977     defined(CONFIG_NF_CT_NETLINK_MODULE)
 978
 979 #include <linux/netfilter/nfnetlink.h>
 980 #include <linux/netfilter/nfnetlink_conntrack.h>
 981 #include <linux/mutex.h>
 982
 983
 984 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 985  * in ip_conntrack_core, since we don't want the protocols to autoload
 986  * or depend on ctnetlink */
 987 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
 988                                const struct nf_conntrack_tuple *tuple)
 989 {
 990         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
 991                 &tuple->src.u.tcp.port);
 992         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
 993                 &tuple->dst.u.tcp.port);
 994         return 0;
 995
 996 nfattr_failure:
 997         return -1;
 998 }
 999 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nfattr);
1000
1001 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
1002         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
1003         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
1004 };
1005
1006 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
1007                                struct nf_conntrack_tuple *t)
1008 {
1009         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
1010                 return -EINVAL;
1011
1012         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
1013                 return -EINVAL;
1014
1015         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
1016         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
1017
1018         return 0;
1019 }
1020 EXPORT_SYMBOL_GPL(nf_ct_port_nfattr_to_tuple);
1021 #endif
1022
1023 /* Used by ipt_REJECT and ip6t_REJECT. */
1024 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1025 {
1026         struct nf_conn *ct;
1027         enum ip_conntrack_info ctinfo;
1028
1029         /* This ICMP is in reverse direction to the packet which caused it */
1030         ct = nf_ct_get(skb, &ctinfo);
1031         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1032                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
1033         else
1034                 ctinfo = IP_CT_RELATED;
1035
1036         /* Attach to new skbuff, and increment count */
1037         nskb->nfct = &ct->ct_general;
1038         nskb->nfctinfo = ctinfo;
1039         nf_conntrack_get(nskb->nfct);
1040 }
1041 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
1042
1043 static inline int
1044 do_iter(const struct nf_conntrack_tuple_hash *i,
1045         int (*iter)(struct nf_conn *i, void *data),
1046         void *data)
1047 {
1048         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1049 }
1050
1051 /* Bring out ya dead! */
1052 static struct nf_conn *
1053 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1054                 void *data, unsigned int *bucket)
1055 {
1056         struct nf_conntrack_tuple_hash *h;
1057         struct nf_conn *ct;
1058
1059         write_lock_bh(&nf_conntrack_lock);
1060         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1061                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1062                         ct = nf_ct_tuplehash_to_ctrack(h);
1063                         if (iter(ct, data))
1064                                 goto found;
1065                 }
1066         }
1067         list_for_each_entry(h, &unconfirmed, list) {
1068                 ct = nf_ct_tuplehash_to_ctrack(h);
1069                 if (iter(ct, data))
1070                         goto found;
1071         }
1072         write_unlock_bh(&nf_conntrack_lock);
1073         return NULL;
1074 found:
1075         atomic_inc(&ct->ct_general.use);
1076         write_unlock_bh(&nf_conntrack_lock);
1077         return ct;
1078 }
1079
1080 void
1081 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1082 {
1083         struct nf_conn *ct;
1084         unsigned int bucket = 0;
1085
1086         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1087                 /* Time to push up daises... */
1088                 if (del_timer(&ct->timeout))
1089                         death_by_timeout((unsigned long)ct);
1090                 /* ... else the timer will get him soon. */
1091
1092                 nf_ct_put(ct);
1093         }
1094 }
1095 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1096
1097 static int kill_all(struct nf_conn *i, void *data)
1098 {
1099         return 1;
1100 }
1101
1102 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1103 {
1104         if (vmalloced)
1105                 vfree(hash);
1106         else
1107                 free_pages((unsigned long)hash,
1108                            get_order(sizeof(struct list_head) * size));
1109 }
1110
1111 void nf_conntrack_flush(void)
1112 {
1113         nf_ct_iterate_cleanup(kill_all, NULL);
1114 }
1115 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
1116
1117 /* Mishearing the voices in his head, our hero wonders how he's
1118    supposed to kill the mall. */
1119 void nf_conntrack_cleanup(void)
1120 {
1121         int i;
1122
1123         rcu_assign_pointer(ip_ct_attach, NULL);
1124
1125         /* This makes sure all current packets have passed through
1126            netfilter framework.  Roll on, two-stage module
1127            delete... */
1128         synchronize_net();
1129
1130         nf_ct_event_cache_flush();
1131  i_see_dead_people:
1132         nf_conntrack_flush();
1133         if (atomic_read(&nf_conntrack_count) != 0) {
1134                 schedule();
1135                 goto i_see_dead_people;
1136         }
1137         /* wait until all references to nf_conntrack_untracked are dropped */
1138         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1139                 schedule();
1140
1141         for (i = 0; i < NF_CT_F_NUM; i++) {
1142                 if (nf_ct_cache[i].use == 0)
1143                         continue;
1144
1145                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1146                 nf_ct_cache[i].use = 1;
1147                 nf_conntrack_unregister_cache(i);
1148         }
1149         kmem_cache_destroy(nf_conntrack_expect_cachep);
1150         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1151                             nf_conntrack_htable_size);
1152
1153         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1154
1155         /* free l3proto protocol tables */
1156         for (i = 0; i < PF_MAX; i++)
1157                 if (nf_ct_protos[i]) {
1158                         kfree(nf_ct_protos[i]);
1159                         nf_ct_protos[i] = NULL;
1160                 }
1161 }
1162
1163 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1164 {
1165         struct list_head *hash;
1166         unsigned int i;
1167
1168         *vmalloced = 0;
1169         hash = (void*)__get_free_pages(GFP_KERNEL,
1170                                        get_order(sizeof(struct list_head)
1171                                                  * size));
1172         if (!hash) {
1173                 *vmalloced = 1;
1174                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1175                 hash = vmalloc(sizeof(struct list_head) * size);
1176         }
1177
1178         if (hash)
1179                 for (i = 0; i < size; i++)
1180                         INIT_LIST_HEAD(&hash[i]);
1181
1182         return hash;
1183 }
1184
1185 int set_hashsize(const char *val, struct kernel_param *kp)
1186 {
1187         int i, bucket, hashsize, vmalloced;
1188         int old_vmalloced, old_size;
1189         int rnd;
1190         struct list_head *hash, *old_hash;
1191         struct nf_conntrack_tuple_hash *h;
1192
1193         /* On boot, we can set this without any fancy locking. */
1194         if (!nf_conntrack_htable_size)
1195                 return param_set_uint(val, kp);
1196
1197         hashsize = simple_strtol(val, NULL, 0);
1198         if (!hashsize)
1199                 return -EINVAL;
1200
1201         hash = alloc_hashtable(hashsize, &vmalloced);
1202         if (!hash)
1203                 return -ENOMEM;
1204
1205         /* We have to rehahs for the new table anyway, so we also can
1206          * use a newrandom seed */
1207         get_random_bytes(&rnd, 4);
1208
1209         write_lock_bh(&nf_conntrack_lock);
1210         for (i = 0; i < nf_conntrack_htable_size; i++) {
1211                 while (!list_empty(&nf_conntrack_hash[i])) {
1212                         h = list_entry(nf_conntrack_hash[i].next,
1213                                        struct nf_conntrack_tuple_hash, list);
1214                         list_del(&h->list);
1215                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1216                         list_add_tail(&h->list, &hash[bucket]);
1217                 }
1218         }
1219         old_size = nf_conntrack_htable_size;
1220         old_vmalloced = nf_conntrack_vmalloc;
1221         old_hash = nf_conntrack_hash;
1222
1223         nf_conntrack_htable_size = hashsize;
1224         nf_conntrack_vmalloc = vmalloced;
1225         nf_conntrack_hash = hash;
1226         nf_conntrack_hash_rnd = rnd;
1227         write_unlock_bh(&nf_conntrack_lock);
1228
1229         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1230         return 0;
1231 }
1232
1233 module_param_call(hashsize, set_hashsize, param_get_uint,
1234                   &nf_conntrack_htable_size, 0600);
1235
1236 int __init nf_conntrack_init(void)
1237 {
1238         unsigned int i;
1239         int ret;
1240
1241         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1242          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1243         if (!nf_conntrack_htable_size) {
1244                 nf_conntrack_htable_size
1245                         = (((num_physpages << PAGE_SHIFT) / 16384)
1246                            / sizeof(struct list_head));
1247                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1248                         nf_conntrack_htable_size = 8192;
1249                 if (nf_conntrack_htable_size < 16)
1250                         nf_conntrack_htable_size = 16;
1251         }
1252         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1253
1254         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1255                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1256                nf_conntrack_max);
1257
1258         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1259                                             &nf_conntrack_vmalloc);
1260         if (!nf_conntrack_hash) {
1261                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1262                 goto err_out;
1263         }
1264
1265         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1266                                           sizeof(struct nf_conn));
1267         if (ret < 0) {
1268                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1269                 goto err_free_hash;
1270         }
1271
1272         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1273                                         sizeof(struct nf_conntrack_expect),
1274                                         0, 0, NULL, NULL);
1275         if (!nf_conntrack_expect_cachep) {
1276                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1277                 goto err_free_conntrack_slab;
1278         }
1279
1280         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1281         if (ret < 0)
1282                 goto out_free_expect_slab;
1283
1284         /* Don't NEED lock here, but good form anyway. */
1285         write_lock_bh(&nf_conntrack_lock);
1286         for (i = 0; i < AF_MAX; i++)
1287                 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1288         write_unlock_bh(&nf_conntrack_lock);
1289
1290         /* For use by REJECT target */
1291         rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
1292
1293         /* Set up fake conntrack:
1294             - to never be deleted, not in any hashes */
1295         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1296         /*  - and look it like as a confirmed connection */
1297         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1298
1299         return ret;
1300
1301 out_free_expect_slab:
1302         kmem_cache_destroy(nf_conntrack_expect_cachep);
1303 err_free_conntrack_slab:
1304         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1305 err_free_hash:
1306         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1307                             nf_conntrack_htable_size);
1308 err_out:
1309         return -ENOMEM;
1310 }