net/netfilter/nf_conntrack_core.c

   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/types.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/module.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/stddef.h>
  21 #include <linux/slab.h>
  22 #include <linux/random.h>
  23 #include <linux/jhash.h>
  24 #include <linux/err.h>
  25 #include <linux/percpu.h>
  26 #include <linux/moduleparam.h>
  27 #include <linux/notifier.h>
  28 #include <linux/kernel.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/socket.h>
  31 #include <linux/mm.h>
  32
  33 #include <net/netfilter/nf_conntrack.h>
  34 #include <net/netfilter/nf_conntrack_l3proto.h>
  35 #include <net/netfilter/nf_conntrack_l4proto.h>
  36 #include <net/netfilter/nf_conntrack_expect.h>
  37 #include <net/netfilter/nf_conntrack_helper.h>
  38 #include <net/netfilter/nf_conntrack_core.h>
  39 #include <net/netfilter/nf_conntrack_extend.h>
  40
  41 #define NF_CONNTRACK_VERSION    "0.5.0"
  42
  43 DEFINE_SPINLOCK(nf_conntrack_lock);
  44 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  45
  46 /* nf_conntrack_standalone needs this */
  47 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  48 EXPORT_SYMBOL_GPL(nf_conntrack_count);
  49
  50 unsigned int nf_conntrack_htable_size __read_mostly;
  51 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  52
  53 int nf_conntrack_max __read_mostly;
  54 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  55
  56 struct hlist_head *nf_conntrack_hash __read_mostly;
  57 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  58
  59 struct nf_conn nf_conntrack_untracked __read_mostly;
  60 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
  61
  62 unsigned int nf_ct_log_invalid __read_mostly;
  63 HLIST_HEAD(unconfirmed);
  64 static int nf_conntrack_vmalloc __read_mostly;
  65 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
  66
  67 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  68 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  69
  70 static int nf_conntrack_hash_rnd_initted;
  71 static unsigned int nf_conntrack_hash_rnd;
  72
  73 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
  74                                   unsigned int size, unsigned int rnd)
  75 {
  76         unsigned int a, b;
  77
  78         a = jhash2(tuple->src.u3.all, ARRAY_SIZE(tuple->src.u3.all),
  79                    (tuple->src.l3num << 16) | tuple->dst.protonum);
  80         b = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
  81                    ((__force __u16)tuple->src.u.all << 16) |
  82                     (__force __u16)tuple->dst.u.all);
  83
  84         return ((u64)jhash_2words(a, b, rnd) * size) >> 32;
  85 }
  86
  87 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
  88 {
  89         return __hash_conntrack(tuple, nf_conntrack_htable_size,
  90                                 nf_conntrack_hash_rnd);
  91 }
  92
  93 int
  94 nf_ct_get_tuple(const struct sk_buff *skb,
  95                 unsigned int nhoff,
  96                 unsigned int dataoff,
  97                 u_int16_t l3num,
  98                 u_int8_t protonum,
  99                 struct nf_conntrack_tuple *tuple,
 100                 const struct nf_conntrack_l3proto *l3proto,
 101                 const struct nf_conntrack_l4proto *l4proto)
 102 {
 103         NF_CT_TUPLE_U_BLANK(tuple);
 104
 105         tuple->src.l3num = l3num;
 106         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 107                 return 0;
 108
 109         tuple->dst.protonum = protonum;
 110         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 111
 112         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 113 }
 114 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 115
 116 int nf_ct_get_tuplepr(const struct sk_buff *skb,
 117                       unsigned int nhoff,
 118                       u_int16_t l3num,
 119                       struct nf_conntrack_tuple *tuple)
 120 {
 121         struct nf_conntrack_l3proto *l3proto;
 122         struct nf_conntrack_l4proto *l4proto;
 123         unsigned int protoff;
 124         u_int8_t protonum;
 125         int ret;
 126
 127         rcu_read_lock();
 128
 129         l3proto = __nf_ct_l3proto_find(l3num);
 130         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 131         if (ret != NF_ACCEPT) {
 132                 rcu_read_unlock();
 133                 return 0;
 134         }
 135
 136         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 137
 138         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 139                               l3proto, l4proto);
 140
 141         rcu_read_unlock();
 142         return ret;
 143 }
 144 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 145
 146 int
 147 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 148                    const struct nf_conntrack_tuple *orig,
 149                    const struct nf_conntrack_l3proto *l3proto,
 150                    const struct nf_conntrack_l4proto *l4proto)
 151 {
 152         NF_CT_TUPLE_U_BLANK(inverse);
 153
 154         inverse->src.l3num = orig->src.l3num;
 155         if (l3proto->invert_tuple(inverse, orig) == 0)
 156                 return 0;
 157
 158         inverse->dst.dir = !orig->dst.dir;
 159
 160         inverse->dst.protonum = orig->dst.protonum;
 161         return l4proto->invert_tuple(inverse, orig);
 162 }
 163 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 164
 165 static void
 166 clean_from_lists(struct nf_conn *ct)
 167 {
 168         pr_debug("clean_from_lists(%p)\n", ct);
 169         hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
 170         hlist_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
 171
 172         /* Destroy all pending expectations */
 173         nf_ct_remove_expectations(ct);
 174 }
 175
 176 static void
 177 destroy_conntrack(struct nf_conntrack *nfct)
 178 {
 179         struct nf_conn *ct = (struct nf_conn *)nfct;
 180         struct nf_conntrack_l4proto *l4proto;
 181
 182         pr_debug("destroy_conntrack(%p)\n", ct);
 183         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 184         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 185
 186         nf_conntrack_event(IPCT_DESTROY, ct);
 187         set_bit(IPS_DYING_BIT, &ct->status);
 188
 189         /* To make sure we don't get any weird locking issues here:
 190          * destroy_conntrack() MUST NOT be called with a write lock
 191          * to nf_conntrack_lock!!! -HW */
 192         rcu_read_lock();
 193         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
 194                                        ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 195         if (l4proto && l4proto->destroy)
 196                 l4proto->destroy(ct);
 197
 198         nf_ct_ext_destroy(ct);
 199
 200         rcu_read_unlock();
 201
 202         spin_lock_bh(&nf_conntrack_lock);
 203         /* Expectations will have been removed in clean_from_lists,
 204          * except TFTP can create an expectation on the first packet,
 205          * before connection is in the list, so we need to clean here,
 206          * too. */
 207         nf_ct_remove_expectations(ct);
 208
 209         /* We overload first tuple to link into unconfirmed list. */
 210         if (!nf_ct_is_confirmed(ct)) {
 211                 BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
 212                 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
 213         }
 214
 215         NF_CT_STAT_INC(delete);
 216         spin_unlock_bh(&nf_conntrack_lock);
 217
 218         if (ct->master)
 219                 nf_ct_put(ct->master);
 220
 221         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 222         nf_conntrack_free(ct);
 223 }
 224
 225 static void death_by_timeout(unsigned long ul_conntrack)
 226 {
 227         struct nf_conn *ct = (void *)ul_conntrack;
 228         struct nf_conn_help *help = nfct_help(ct);
 229         struct nf_conntrack_helper *helper;
 230
 231         if (help) {
 232                 rcu_read_lock();
 233                 helper = rcu_dereference(help->helper);
 234                 if (helper && helper->destroy)
 235                         helper->destroy(ct);
 236                 rcu_read_unlock();
 237         }
 238
 239         spin_lock_bh(&nf_conntrack_lock);
 240         /* Inside lock so preempt is disabled on module removal path.
 241          * Otherwise we can get spurious warnings. */
 242         NF_CT_STAT_INC(delete_list);
 243         clean_from_lists(ct);
 244         spin_unlock_bh(&nf_conntrack_lock);
 245         nf_ct_put(ct);
 246 }
 247
 248 struct nf_conntrack_tuple_hash *
 249 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 250                     const struct nf_conn *ignored_conntrack)
 251 {
 252         struct nf_conntrack_tuple_hash *h;
 253         struct hlist_node *n;
 254         unsigned int hash = hash_conntrack(tuple);
 255
 256         hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash], hnode) {
 257                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 258                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 259                         NF_CT_STAT_INC(found);
 260                         return h;
 261                 }
 262                 NF_CT_STAT_INC(searched);
 263         }
 264
 265         return NULL;
 266 }
 267 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 268
 269 /* Find a connection corresponding to a tuple. */
 270 struct nf_conntrack_tuple_hash *
 271 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple)
 272 {
 273         struct nf_conntrack_tuple_hash *h;
 274         struct nf_conn *ct;
 275
 276         rcu_read_lock();
 277         h = __nf_conntrack_find(tuple, NULL);
 278         if (h) {
 279                 ct = nf_ct_tuplehash_to_ctrack(h);
 280                 if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
 281                         h = NULL;
 282         }
 283         rcu_read_unlock();
 284
 285         return h;
 286 }
 287 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 288
 289 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 290                                        unsigned int hash,
 291                                        unsigned int repl_hash)
 292 {
 293         hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
 294                            &nf_conntrack_hash[hash]);
 295         hlist_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
 296                            &nf_conntrack_hash[repl_hash]);
 297 }
 298
 299 void nf_conntrack_hash_insert(struct nf_conn *ct)
 300 {
 301         unsigned int hash, repl_hash;
 302
 303         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 304         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 305
 306         spin_lock_bh(&nf_conntrack_lock);
 307         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 308         spin_unlock_bh(&nf_conntrack_lock);
 309 }
 310 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 311
 312 /* Confirm a connection given skb; places it in hash table */
 313 int
 314 __nf_conntrack_confirm(struct sk_buff *skb)
 315 {
 316         unsigned int hash, repl_hash;
 317         struct nf_conntrack_tuple_hash *h;
 318         struct nf_conn *ct;
 319         struct nf_conn_help *help;
 320         struct hlist_node *n;
 321         enum ip_conntrack_info ctinfo;
 322
 323         ct = nf_ct_get(skb, &ctinfo);
 324
 325         /* ipt_REJECT uses nf_conntrack_attach to attach related
 326            ICMP/TCP RST packets in other direction.  Actual packet
 327            which created connection will be IP_CT_NEW or for an
 328            expected connection, IP_CT_RELATED. */
 329         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 330                 return NF_ACCEPT;
 331
 332         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 333         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 334
 335         /* We're not in hash table, and we refuse to set up related
 336            connections for unconfirmed conns.  But packet copies and
 337            REJECT will give spurious warnings here. */
 338         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 339
 340         /* No external references means noone else could have
 341            confirmed us. */
 342         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 343         pr_debug("Confirming conntrack %p\n", ct);
 344
 345         spin_lock_bh(&nf_conntrack_lock);
 346
 347         /* See if there's one in the list already, including reverse:
 348            NAT could have grabbed it without realizing, since we're
 349            not in the hash.  If there is, we lost race. */
 350         hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode)
 351                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 352                                       &h->tuple))
 353                         goto out;
 354         hlist_for_each_entry(h, n, &nf_conntrack_hash[repl_hash], hnode)
 355                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 356                                       &h->tuple))
 357                         goto out;
 358
 359         /* Remove from unconfirmed list */
 360         hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
 361
 362         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 363         /* Timer relative to confirmation time, not original
 364            setting time, otherwise we'd get timer wrap in
 365            weird delay cases. */
 366         ct->timeout.expires += jiffies;
 367         add_timer(&ct->timeout);
 368         atomic_inc(&ct->ct_general.use);
 369         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 370         NF_CT_STAT_INC(insert);
 371         spin_unlock_bh(&nf_conntrack_lock);
 372         help = nfct_help(ct);
 373         if (help && help->helper)
 374                 nf_conntrack_event_cache(IPCT_HELPER, skb);
 375 #ifdef CONFIG_NF_NAT_NEEDED
 376         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 377             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 378                 nf_conntrack_event_cache(IPCT_NATINFO, skb);
 379 #endif
 380         nf_conntrack_event_cache(master_ct(ct) ?
 381                                  IPCT_RELATED : IPCT_NEW, skb);
 382         return NF_ACCEPT;
 383
 384 out:
 385         NF_CT_STAT_INC(insert_failed);
 386         spin_unlock_bh(&nf_conntrack_lock);
 387         return NF_DROP;
 388 }
 389 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 390
 391 /* Returns true if a connection correspondings to the tuple (required
 392    for NAT). */
 393 int
 394 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 395                          const struct nf_conn *ignored_conntrack)
 396 {
 397         struct nf_conntrack_tuple_hash *h;
 398
 399         rcu_read_lock();
 400         h = __nf_conntrack_find(tuple, ignored_conntrack);
 401         rcu_read_unlock();
 402
 403         return h != NULL;
 404 }
 405 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 406
 407 #define NF_CT_EVICTION_RANGE    8
 408
 409 /* There's a small race here where we may free a just-assured
 410    connection.  Too bad: we're in trouble anyway. */
 411 static int early_drop(unsigned int hash)
 412 {
 413         /* Use oldest entry, which is roughly LRU */
 414         struct nf_conntrack_tuple_hash *h;
 415         struct nf_conn *ct = NULL, *tmp;
 416         struct hlist_node *n;
 417         unsigned int i, cnt = 0;
 418         int dropped = 0;
 419
 420         rcu_read_lock();
 421         for (i = 0; i < nf_conntrack_htable_size; i++) {
 422                 hlist_for_each_entry_rcu(h, n, &nf_conntrack_hash[hash],
 423                                          hnode) {
 424                         tmp = nf_ct_tuplehash_to_ctrack(h);
 425                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 426                                 ct = tmp;
 427                         cnt++;
 428                 }
 429
 430                 if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
 431                         ct = NULL;
 432                 if (ct || cnt >= NF_CT_EVICTION_RANGE)
 433                         break;
 434                 hash = (hash + 1) % nf_conntrack_htable_size;
 435         }
 436         rcu_read_unlock();
 437
 438         if (!ct)
 439                 return dropped;
 440
 441         if (del_timer(&ct->timeout)) {
 442                 death_by_timeout((unsigned long)ct);
 443                 dropped = 1;
 444                 NF_CT_STAT_INC_ATOMIC(early_drop);
 445         }
 446         nf_ct_put(ct);
 447         return dropped;
 448 }
 449
 450 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 451                                    const struct nf_conntrack_tuple *repl)
 452 {
 453         struct nf_conn *conntrack = NULL;
 454
 455         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 456                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 457                 nf_conntrack_hash_rnd_initted = 1;
 458         }
 459
 460         /* We don't want any race condition at early drop stage */
 461         atomic_inc(&nf_conntrack_count);
 462
 463         if (nf_conntrack_max
 464             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 465                 unsigned int hash = hash_conntrack(orig);
 466                 if (!early_drop(hash)) {
 467                         atomic_dec(&nf_conntrack_count);
 468                         if (net_ratelimit())
 469                                 printk(KERN_WARNING
 470                                        "nf_conntrack: table full, dropping"
 471                                        " packet.\n");
 472                         return ERR_PTR(-ENOMEM);
 473                 }
 474         }
 475
 476         conntrack = kmem_cache_zalloc(nf_conntrack_cachep, GFP_ATOMIC);
 477         if (conntrack == NULL) {
 478                 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
 479                 atomic_dec(&nf_conntrack_count);
 480                 return ERR_PTR(-ENOMEM);
 481         }
 482
 483         atomic_set(&conntrack->ct_general.use, 1);
 484         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 485         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 486         /* Don't set timer yet: wait for confirmation */
 487         setup_timer(&conntrack->timeout, death_by_timeout,
 488                     (unsigned long)conntrack);
 489         INIT_RCU_HEAD(&conntrack->rcu);
 490
 491         return conntrack;
 492 }
 493 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 494
 495 static void nf_conntrack_free_rcu(struct rcu_head *head)
 496 {
 497         struct nf_conn *ct = container_of(head, struct nf_conn, rcu);
 498
 499         nf_ct_ext_free(ct);
 500         kmem_cache_free(nf_conntrack_cachep, ct);
 501         atomic_dec(&nf_conntrack_count);
 502 }
 503
 504 void nf_conntrack_free(struct nf_conn *conntrack)
 505 {
 506         call_rcu(&conntrack->rcu, nf_conntrack_free_rcu);
 507 }
 508 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 509
 510 /* Allocate a new conntrack: we return -ENOMEM if classification
 511    failed due to stress.  Otherwise it really is unclassifiable. */
 512 static struct nf_conntrack_tuple_hash *
 513 init_conntrack(const struct nf_conntrack_tuple *tuple,
 514                struct nf_conntrack_l3proto *l3proto,
 515                struct nf_conntrack_l4proto *l4proto,
 516                struct sk_buff *skb,
 517                unsigned int dataoff)
 518 {
 519         struct nf_conn *conntrack;
 520         struct nf_conn_help *help;
 521         struct nf_conntrack_tuple repl_tuple;
 522         struct nf_conntrack_expect *exp;
 523
 524         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 525                 pr_debug("Can't invert tuple.\n");
 526                 return NULL;
 527         }
 528
 529         conntrack = nf_conntrack_alloc(tuple, &repl_tuple);
 530         if (conntrack == NULL || IS_ERR(conntrack)) {
 531                 pr_debug("Can't allocate conntrack.\n");
 532                 return (struct nf_conntrack_tuple_hash *)conntrack;
 533         }
 534
 535         if (!l4proto->new(conntrack, skb, dataoff)) {
 536                 nf_conntrack_free(conntrack);
 537                 pr_debug("init conntrack: can't track with proto module\n");
 538                 return NULL;
 539         }
 540
 541         spin_lock_bh(&nf_conntrack_lock);
 542         exp = nf_ct_find_expectation(tuple);
 543         if (exp) {
 544                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 545                          conntrack, exp);
 546                 /* Welcome, Mr. Bond.  We've been expecting you... */
 547                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 548                 conntrack->master = exp->master;
 549                 if (exp->helper) {
 550                         help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC);
 551                         if (help)
 552                                 rcu_assign_pointer(help->helper, exp->helper);
 553                 }
 554
 555 #ifdef CONFIG_NF_CONNTRACK_MARK
 556                 conntrack->mark = exp->master->mark;
 557 #endif
 558 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 559                 conntrack->secmark = exp->master->secmark;
 560 #endif
 561                 nf_conntrack_get(&conntrack->master->ct_general);
 562                 NF_CT_STAT_INC(expect_new);
 563         } else {
 564                 struct nf_conntrack_helper *helper;
 565
 566                 helper = __nf_ct_helper_find(&repl_tuple);
 567                 if (helper) {
 568                         help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC);
 569                         if (help)
 570                                 rcu_assign_pointer(help->helper, helper);
 571                 }
 572                 NF_CT_STAT_INC(new);
 573         }
 574
 575         /* Overload tuple linked list to put us in unconfirmed list. */
 576         hlist_add_head(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
 577                        &unconfirmed);
 578
 579         spin_unlock_bh(&nf_conntrack_lock);
 580
 581         if (exp) {
 582                 if (exp->expectfn)
 583                         exp->expectfn(conntrack, exp);
 584                 nf_ct_expect_put(exp);
 585         }
 586
 587         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 588 }
 589
 590 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 591 static inline struct nf_conn *
 592 resolve_normal_ct(struct sk_buff *skb,
 593                   unsigned int dataoff,
 594                   u_int16_t l3num,
 595                   u_int8_t protonum,
 596                   struct nf_conntrack_l3proto *l3proto,
 597                   struct nf_conntrack_l4proto *l4proto,
 598                   int *set_reply,
 599                   enum ip_conntrack_info *ctinfo)
 600 {
 601         struct nf_conntrack_tuple tuple;
 602         struct nf_conntrack_tuple_hash *h;
 603         struct nf_conn *ct;
 604
 605         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 606                              dataoff, l3num, protonum, &tuple, l3proto,
 607                              l4proto)) {
 608                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 609                 return NULL;
 610         }
 611
 612         /* look for tuple match */
 613         h = nf_conntrack_find_get(&tuple);
 614         if (!h) {
 615                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 616                 if (!h)
 617                         return NULL;
 618                 if (IS_ERR(h))
 619                         return (void *)h;
 620         }
 621         ct = nf_ct_tuplehash_to_ctrack(h);
 622
 623         /* It exists; we have (non-exclusive) reference. */
 624         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 625                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 626                 /* Please set reply bit if this packet OK */
 627                 *set_reply = 1;
 628         } else {
 629                 /* Once we've had two way comms, always ESTABLISHED. */
 630                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 631                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 632                         *ctinfo = IP_CT_ESTABLISHED;
 633                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 634                         pr_debug("nf_conntrack_in: related packet for %p\n",
 635                                  ct);
 636                         *ctinfo = IP_CT_RELATED;
 637                 } else {
 638                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 639                         *ctinfo = IP_CT_NEW;
 640                 }
 641                 *set_reply = 0;
 642         }
 643         skb->nfct = &ct->ct_general;
 644         skb->nfctinfo = *ctinfo;
 645         return ct;
 646 }
 647
 648 unsigned int
 649 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff *skb)
 650 {
 651         struct nf_conn *ct;
 652         enum ip_conntrack_info ctinfo;
 653         struct nf_conntrack_l3proto *l3proto;
 654         struct nf_conntrack_l4proto *l4proto;
 655         unsigned int dataoff;
 656         u_int8_t protonum;
 657         int set_reply = 0;
 658         int ret;
 659
 660         /* Previously seen (loopback or untracked)?  Ignore. */
 661         if (skb->nfct) {
 662                 NF_CT_STAT_INC_ATOMIC(ignore);
 663                 return NF_ACCEPT;
 664         }
 665
 666         /* rcu_read_lock()ed by nf_hook_slow */
 667         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 668         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 669                                    &dataoff, &protonum);
 670         if (ret <= 0) {
 671                 pr_debug("not prepared to track yet or error occured\n");
 672                 NF_CT_STAT_INC_ATOMIC(error);
 673                 NF_CT_STAT_INC_ATOMIC(invalid);
 674                 return -ret;
 675         }
 676
 677         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
 678
 679         /* It may be an special packet, error, unclean...
 680          * inverse of the return code tells to the netfilter
 681          * core what to do with the packet. */
 682         if (l4proto->error != NULL &&
 683             (ret = l4proto->error(skb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 684                 NF_CT_STAT_INC_ATOMIC(error);
 685                 NF_CT_STAT_INC_ATOMIC(invalid);
 686                 return -ret;
 687         }
 688
 689         ct = resolve_normal_ct(skb, dataoff, pf, protonum, l3proto, l4proto,
 690                                &set_reply, &ctinfo);
 691         if (!ct) {
 692                 /* Not valid part of a connection */
 693                 NF_CT_STAT_INC_ATOMIC(invalid);
 694                 return NF_ACCEPT;
 695         }
 696
 697         if (IS_ERR(ct)) {
 698                 /* Too stressed to deal. */
 699                 NF_CT_STAT_INC_ATOMIC(drop);
 700                 return NF_DROP;
 701         }
 702
 703         NF_CT_ASSERT(skb->nfct);
 704
 705         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
 706         if (ret < 0) {
 707                 /* Invalid: inverse of the return code tells
 708                  * the netfilter core what to do */
 709                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
 710                 nf_conntrack_put(skb->nfct);
 711                 skb->nfct = NULL;
 712                 NF_CT_STAT_INC_ATOMIC(invalid);
 713                 return -ret;
 714         }
 715
 716         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 717                 nf_conntrack_event_cache(IPCT_STATUS, skb);
 718
 719         return ret;
 720 }
 721 EXPORT_SYMBOL_GPL(nf_conntrack_in);
 722
 723 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 724                          const struct nf_conntrack_tuple *orig)
 725 {
 726         int ret;
 727
 728         rcu_read_lock();
 729         ret = nf_ct_invert_tuple(inverse, orig,
 730                                  __nf_ct_l3proto_find(orig->src.l3num),
 731                                  __nf_ct_l4proto_find(orig->src.l3num,
 732                                                       orig->dst.protonum));
 733         rcu_read_unlock();
 734         return ret;
 735 }
 736 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 737
 738 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 739    implicitly racy: see __nf_conntrack_confirm */
 740 void nf_conntrack_alter_reply(struct nf_conn *ct,
 741                               const struct nf_conntrack_tuple *newreply)
 742 {
 743         struct nf_conn_help *help = nfct_help(ct);
 744         struct nf_conntrack_helper *helper;
 745
 746         /* Should be unconfirmed, so not in hash table yet */
 747         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 748
 749         pr_debug("Altering reply tuple of %p to ", ct);
 750         NF_CT_DUMP_TUPLE(newreply);
 751
 752         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 753         if (ct->master || (help && help->expecting != 0))
 754                 return;
 755
 756         rcu_read_lock();
 757         helper = __nf_ct_helper_find(newreply);
 758         if (helper == NULL) {
 759                 if (help)
 760                         rcu_assign_pointer(help->helper, NULL);
 761                 goto out;
 762         }
 763
 764         if (help == NULL) {
 765                 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
 766                 if (help == NULL)
 767                         goto out;
 768         } else {
 769                 memset(&help->help, 0, sizeof(help->help));
 770         }
 771
 772         rcu_assign_pointer(help->helper, helper);
 773 out:
 774         rcu_read_unlock();
 775 }
 776 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 777
 778 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 779 void __nf_ct_refresh_acct(struct nf_conn *ct,
 780                           enum ip_conntrack_info ctinfo,
 781                           const struct sk_buff *skb,
 782                           unsigned long extra_jiffies,
 783                           int do_acct)
 784 {
 785         int event = 0;
 786
 787         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 788         NF_CT_ASSERT(skb);
 789
 790         spin_lock_bh(&nf_conntrack_lock);
 791
 792         /* Only update if this is not a fixed timeout */
 793         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
 794                 goto acct;
 795
 796         /* If not in hash table, timer will not be active yet */
 797         if (!nf_ct_is_confirmed(ct)) {
 798                 ct->timeout.expires = extra_jiffies;
 799                 event = IPCT_REFRESH;
 800         } else {
 801                 unsigned long newtime = jiffies + extra_jiffies;
 802
 803                 /* Only update the timeout if the new timeout is at least
 804                    HZ jiffies from the old timeout. Need del_timer for race
 805                    avoidance (may already be dying). */
 806                 if (newtime - ct->timeout.expires >= HZ
 807                     && del_timer(&ct->timeout)) {
 808                         ct->timeout.expires = newtime;
 809                         add_timer(&ct->timeout);
 810                         event = IPCT_REFRESH;
 811                 }
 812         }
 813
 814 acct:
 815 #ifdef CONFIG_NF_CT_ACCT
 816         if (do_acct) {
 817                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 818                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 819                         skb->len - skb_network_offset(skb);
 820
 821                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 822                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 823                         event |= IPCT_COUNTER_FILLING;
 824         }
 825 #endif
 826
 827         spin_unlock_bh(&nf_conntrack_lock);
 828
 829         /* must be unlocked when calling event cache */
 830         if (event)
 831                 nf_conntrack_event_cache(event, skb);
 832 }
 833 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 834
 835 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 836
 837 #include <linux/netfilter/nfnetlink.h>
 838 #include <linux/netfilter/nfnetlink_conntrack.h>
 839 #include <linux/mutex.h>
 840
 841 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 842  * in ip_conntrack_core, since we don't want the protocols to autoload
 843  * or depend on ctnetlink */
 844 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
 845                                const struct nf_conntrack_tuple *tuple)
 846 {
 847         NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
 848         NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
 849         return 0;
 850
 851 nla_put_failure:
 852         return -1;
 853 }
 854 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
 855
 856 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
 857         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
 858         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
 859 };
 860 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
 861
 862 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
 863                                struct nf_conntrack_tuple *t)
 864 {
 865         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
 866                 return -EINVAL;
 867
 868         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
 869         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
 870
 871         return 0;
 872 }
 873 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
 874 #endif
 875
 876 /* Used by ipt_REJECT and ip6t_REJECT. */
 877 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
 878 {
 879         struct nf_conn *ct;
 880         enum ip_conntrack_info ctinfo;
 881
 882         /* This ICMP is in reverse direction to the packet which caused it */
 883         ct = nf_ct_get(skb, &ctinfo);
 884         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
 885                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
 886         else
 887                 ctinfo = IP_CT_RELATED;
 888
 889         /* Attach to new skbuff, and increment count */
 890         nskb->nfct = &ct->ct_general;
 891         nskb->nfctinfo = ctinfo;
 892         nf_conntrack_get(nskb->nfct);
 893 }
 894
 895 static inline int
 896 do_iter(const struct nf_conntrack_tuple_hash *i,
 897         int (*iter)(struct nf_conn *i, void *data),
 898         void *data)
 899 {
 900         return iter(nf_ct_tuplehash_to_ctrack(i), data);
 901 }
 902
 903 /* Bring out ya dead! */
 904 static struct nf_conn *
 905 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
 906                 void *data, unsigned int *bucket)
 907 {
 908         struct nf_conntrack_tuple_hash *h;
 909         struct nf_conn *ct;
 910         struct hlist_node *n;
 911
 912         spin_lock_bh(&nf_conntrack_lock);
 913         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
 914                 hlist_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnode) {
 915                         ct = nf_ct_tuplehash_to_ctrack(h);
 916                         if (iter(ct, data))
 917                                 goto found;
 918                 }
 919         }
 920         hlist_for_each_entry(h, n, &unconfirmed, hnode) {
 921                 ct = nf_ct_tuplehash_to_ctrack(h);
 922                 if (iter(ct, data))
 923                         set_bit(IPS_DYING_BIT, &ct->status);
 924         }
 925         spin_unlock_bh(&nf_conntrack_lock);
 926         return NULL;
 927 found:
 928         atomic_inc(&ct->ct_general.use);
 929         spin_unlock_bh(&nf_conntrack_lock);
 930         return ct;
 931 }
 932
 933 void
 934 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
 935 {
 936         struct nf_conn *ct;
 937         unsigned int bucket = 0;
 938
 939         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
 940                 /* Time to push up daises... */
 941                 if (del_timer(&ct->timeout))
 942                         death_by_timeout((unsigned long)ct);
 943                 /* ... else the timer will get him soon. */
 944
 945                 nf_ct_put(ct);
 946         }
 947 }
 948 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
 949
 950 static int kill_all(struct nf_conn *i, void *data)
 951 {
 952         return 1;
 953 }
 954
 955 void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, unsigned int size)
 956 {
 957         if (vmalloced)
 958                 vfree(hash);
 959         else
 960                 free_pages((unsigned long)hash,
 961                            get_order(sizeof(struct hlist_head) * size));
 962 }
 963 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
 964
 965 void nf_conntrack_flush(void)
 966 {
 967         nf_ct_iterate_cleanup(kill_all, NULL);
 968 }
 969 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
 970
 971 /* Mishearing the voices in his head, our hero wonders how he's
 972    supposed to kill the mall. */
 973 void nf_conntrack_cleanup(void)
 974 {
 975         rcu_assign_pointer(ip_ct_attach, NULL);
 976
 977         /* This makes sure all current packets have passed through
 978            netfilter framework.  Roll on, two-stage module
 979            delete... */
 980         synchronize_net();
 981
 982         nf_ct_event_cache_flush();
 983  i_see_dead_people:
 984         nf_conntrack_flush();
 985         if (atomic_read(&nf_conntrack_count) != 0) {
 986                 schedule();
 987                 goto i_see_dead_people;
 988         }
 989         /* wait until all references to nf_conntrack_untracked are dropped */
 990         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
 991                 schedule();
 992
 993         rcu_assign_pointer(nf_ct_destroy, NULL);
 994
 995         kmem_cache_destroy(nf_conntrack_cachep);
 996         nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
 997                              nf_conntrack_htable_size);
 998
 999         nf_conntrack_proto_fini();
1000         nf_conntrack_helper_fini();
1001         nf_conntrack_expect_fini();
1002 }
1003
1004 struct hlist_head *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced)
1005 {
1006         struct hlist_head *hash;
1007         unsigned int size, i;
1008
1009         *vmalloced = 0;
1010
1011         size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
1012         hash = (void*)__get_free_pages(GFP_KERNEL|__GFP_NOWARN,
1013                                        get_order(sizeof(struct hlist_head)
1014                                                  * size));
1015         if (!hash) {
1016                 *vmalloced = 1;
1017                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1018                 hash = vmalloc(sizeof(struct hlist_head) * size);
1019         }
1020
1021         if (hash)
1022                 for (i = 0; i < size; i++)
1023                         INIT_HLIST_HEAD(&hash[i]);
1024
1025         return hash;
1026 }
1027 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1028
1029 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1030 {
1031         int i, bucket, vmalloced, old_vmalloced;
1032         unsigned int hashsize, old_size;
1033         int rnd;
1034         struct hlist_head *hash, *old_hash;
1035         struct nf_conntrack_tuple_hash *h;
1036
1037         /* On boot, we can set this without any fancy locking. */
1038         if (!nf_conntrack_htable_size)
1039                 return param_set_uint(val, kp);
1040
1041         hashsize = simple_strtoul(val, NULL, 0);
1042         if (!hashsize)
1043                 return -EINVAL;
1044
1045         hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
1046         if (!hash)
1047                 return -ENOMEM;
1048
1049         /* We have to rehahs for the new table anyway, so we also can
1050          * use a newrandom seed */
1051         get_random_bytes(&rnd, 4);
1052
1053         /* Lookups in the old hash might happen in parallel, which means we
1054          * might get false negatives during connection lookup. New connections
1055          * created because of a false negative won't make it into the hash
1056          * though since that required taking the lock.
1057          */
1058         spin_lock_bh(&nf_conntrack_lock);
1059         for (i = 0; i < nf_conntrack_htable_size; i++) {
1060                 while (!hlist_empty(&nf_conntrack_hash[i])) {
1061                         h = hlist_entry(nf_conntrack_hash[i].first,
1062                                         struct nf_conntrack_tuple_hash, hnode);
1063                         hlist_del_rcu(&h->hnode);
1064                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1065                         hlist_add_head(&h->hnode, &hash[bucket]);
1066                 }
1067         }
1068         old_size = nf_conntrack_htable_size;
1069         old_vmalloced = nf_conntrack_vmalloc;
1070         old_hash = nf_conntrack_hash;
1071
1072         nf_conntrack_htable_size = hashsize;
1073         nf_conntrack_vmalloc = vmalloced;
1074         nf_conntrack_hash = hash;
1075         nf_conntrack_hash_rnd = rnd;
1076         spin_unlock_bh(&nf_conntrack_lock);
1077
1078         nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1079         return 0;
1080 }
1081 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1082
1083 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1084                   &nf_conntrack_htable_size, 0600);
1085
1086 int __init nf_conntrack_init(void)
1087 {
1088         int max_factor = 8;
1089         int ret;
1090
1091         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1092          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1093         if (!nf_conntrack_htable_size) {
1094                 nf_conntrack_htable_size
1095                         = (((num_physpages << PAGE_SHIFT) / 16384)
1096                            / sizeof(struct hlist_head));
1097                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1098                         nf_conntrack_htable_size = 16384;
1099                 if (nf_conntrack_htable_size < 32)
1100                         nf_conntrack_htable_size = 32;
1101
1102                 /* Use a max. factor of four by default to get the same max as
1103                  * with the old struct list_heads. When a table size is given
1104                  * we use the old value of 8 to avoid reducing the max.
1105                  * entries. */
1106                 max_factor = 4;
1107         }
1108         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1109                                                   &nf_conntrack_vmalloc);
1110         if (!nf_conntrack_hash) {
1111                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1112                 goto err_out;
1113         }
1114
1115         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1116
1117         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1118                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1119                nf_conntrack_max);
1120
1121         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1122                                                 sizeof(struct nf_conn),
1123                                                 0, 0, NULL);
1124         if (!nf_conntrack_cachep) {
1125                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1126                 goto err_free_hash;
1127         }
1128
1129         ret = nf_conntrack_proto_init();
1130         if (ret < 0)
1131                 goto err_free_conntrack_slab;
1132
1133         ret = nf_conntrack_expect_init();
1134         if (ret < 0)
1135                 goto out_fini_proto;
1136
1137         ret = nf_conntrack_helper_init();
1138         if (ret < 0)
1139                 goto out_fini_expect;
1140
1141         /* For use by REJECT target */
1142         rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1143         rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1144
1145         /* Set up fake conntrack:
1146             - to never be deleted, not in any hashes */
1147         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1148         /*  - and look it like as a confirmed connection */
1149         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1150
1151         return ret;
1152
1153 out_fini_expect:
1154         nf_conntrack_expect_fini();
1155 out_fini_proto:
1156         nf_conntrack_proto_fini();
1157 err_free_conntrack_slab:
1158         kmem_cache_destroy(nf_conntrack_cachep);
1159 err_free_hash:
1160         nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1161                              nf_conntrack_htable_size);
1162 err_out:
1163         return -ENOMEM;
1164 }