SAFE public projects git trees. - safe/jmp/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
  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_RWLOCK(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 static unsigned int nf_conntrack_next_id;
  67
  68 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  69 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  70
  71 static int nf_conntrack_hash_rnd_initted;
  72 static unsigned int nf_conntrack_hash_rnd;
  73
  74 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
  75                                   unsigned int size, unsigned int rnd)
  76 {
  77         unsigned int a, b;
  78
  79         a = jhash2(tuple->src.u3.all, ARRAY_SIZE(tuple->src.u3.all),
  80                    (tuple->src.l3num << 16) | tuple->dst.protonum);
  81         b = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
  82                    ((__force __u16)tuple->src.u.all << 16) |
  83                     (__force __u16)tuple->dst.u.all);
  84
  85         return jhash_2words(a, b, rnd) % size;
  86 }
  87
  88 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
  89 {
  90         return __hash_conntrack(tuple, nf_conntrack_htable_size,
  91                                 nf_conntrack_hash_rnd);
  92 }
  93
  94 int
  95 nf_ct_get_tuple(const struct sk_buff *skb,
  96                 unsigned int nhoff,
  97                 unsigned int dataoff,
  98                 u_int16_t l3num,
  99                 u_int8_t protonum,
 100                 struct nf_conntrack_tuple *tuple,
 101                 const struct nf_conntrack_l3proto *l3proto,
 102                 const struct nf_conntrack_l4proto *l4proto)
 103 {
 104         NF_CT_TUPLE_U_BLANK(tuple);
 105
 106         tuple->src.l3num = l3num;
 107         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 108                 return 0;
 109
 110         tuple->dst.protonum = protonum;
 111         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 112
 113         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 114 }
 115 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 116
 117 int nf_ct_get_tuplepr(const struct sk_buff *skb,
 118                       unsigned int nhoff,
 119                       u_int16_t l3num,
 120                       struct nf_conntrack_tuple *tuple)
 121 {
 122         struct nf_conntrack_l3proto *l3proto;
 123         struct nf_conntrack_l4proto *l4proto;
 124         unsigned int protoff;
 125         u_int8_t protonum;
 126         int ret;
 127
 128         rcu_read_lock();
 129
 130         l3proto = __nf_ct_l3proto_find(l3num);
 131         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 132         if (ret != NF_ACCEPT) {
 133                 rcu_read_unlock();
 134                 return 0;
 135         }
 136
 137         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 138
 139         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 140                               l3proto, l4proto);
 141
 142         rcu_read_unlock();
 143         return ret;
 144 }
 145 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 146
 147 int
 148 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 149                    const struct nf_conntrack_tuple *orig,
 150                    const struct nf_conntrack_l3proto *l3proto,
 151                    const struct nf_conntrack_l4proto *l4proto)
 152 {
 153         NF_CT_TUPLE_U_BLANK(inverse);
 154
 155         inverse->src.l3num = orig->src.l3num;
 156         if (l3proto->invert_tuple(inverse, orig) == 0)
 157                 return 0;
 158
 159         inverse->dst.dir = !orig->dst.dir;
 160
 161         inverse->dst.protonum = orig->dst.protonum;
 162         return l4proto->invert_tuple(inverse, orig);
 163 }
 164 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 165
 166 static void
 167 clean_from_lists(struct nf_conn *ct)
 168 {
 169         pr_debug("clean_from_lists(%p)\n", ct);
 170         hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
 171         hlist_del(&ct->tuplehash[IP_CT_DIR_REPLY].hnode);
 172
 173         /* Destroy all pending expectations */
 174         nf_ct_remove_expectations(ct);
 175 }
 176
 177 static void
 178 destroy_conntrack(struct nf_conntrack *nfct)
 179 {
 180         struct nf_conn *ct = (struct nf_conn *)nfct;
 181         struct nf_conntrack_l4proto *l4proto;
 182
 183         pr_debug("destroy_conntrack(%p)\n", ct);
 184         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 185         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 186
 187         nf_conntrack_event(IPCT_DESTROY, ct);
 188         set_bit(IPS_DYING_BIT, &ct->status);
 189
 190         /* To make sure we don't get any weird locking issues here:
 191          * destroy_conntrack() MUST NOT be called with a write lock
 192          * to nf_conntrack_lock!!! -HW */
 193         rcu_read_lock();
 194         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num,
 195                                        ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 196         if (l4proto && l4proto->destroy)
 197                 l4proto->destroy(ct);
 198
 199         nf_ct_ext_destroy(ct);
 200
 201         rcu_read_unlock();
 202
 203         write_lock_bh(&nf_conntrack_lock);
 204         /* Expectations will have been removed in clean_from_lists,
 205          * except TFTP can create an expectation on the first packet,
 206          * before connection is in the list, so we need to clean here,
 207          * too. */
 208         nf_ct_remove_expectations(ct);
 209
 210         /* We overload first tuple to link into unconfirmed list. */
 211         if (!nf_ct_is_confirmed(ct)) {
 212                 BUG_ON(hlist_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode));
 213                 hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
 214         }
 215
 216         NF_CT_STAT_INC(delete);
 217         write_unlock_bh(&nf_conntrack_lock);
 218
 219         if (ct->master)
 220                 nf_ct_put(ct->master);
 221
 222         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 223         nf_conntrack_free(ct);
 224 }
 225
 226 static void death_by_timeout(unsigned long ul_conntrack)
 227 {
 228         struct nf_conn *ct = (void *)ul_conntrack;
 229         struct nf_conn_help *help = nfct_help(ct);
 230         struct nf_conntrack_helper *helper;
 231
 232         if (help) {
 233                 rcu_read_lock();
 234                 helper = rcu_dereference(help->helper);
 235                 if (helper && helper->destroy)
 236                         helper->destroy(ct);
 237                 rcu_read_unlock();
 238         }
 239
 240         write_lock_bh(&nf_conntrack_lock);
 241         /* Inside lock so preempt is disabled on module removal path.
 242          * Otherwise we can get spurious warnings. */
 243         NF_CT_STAT_INC(delete_list);
 244         clean_from_lists(ct);
 245         write_unlock_bh(&nf_conntrack_lock);
 246         nf_ct_put(ct);
 247 }
 248
 249 struct nf_conntrack_tuple_hash *
 250 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 251                     const struct nf_conn *ignored_conntrack)
 252 {
 253         struct nf_conntrack_tuple_hash *h;
 254         struct hlist_node *n;
 255         unsigned int hash = hash_conntrack(tuple);
 256
 257         hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode) {
 258                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 259                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 260                         NF_CT_STAT_INC(found);
 261                         return h;
 262                 }
 263                 NF_CT_STAT_INC(searched);
 264         }
 265
 266         return NULL;
 267 }
 268 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 269
 270 /* Find a connection corresponding to a tuple. */
 271 struct nf_conntrack_tuple_hash *
 272 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple)
 273 {
 274         struct nf_conntrack_tuple_hash *h;
 275
 276         read_lock_bh(&nf_conntrack_lock);
 277         h = __nf_conntrack_find(tuple, NULL);
 278         if (h)
 279                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 280         read_unlock_bh(&nf_conntrack_lock);
 281
 282         return h;
 283 }
 284 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 285
 286 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 287                                        unsigned int hash,
 288                                        unsigned int repl_hash)
 289 {
 290         ct->id = ++nf_conntrack_next_id;
 291         hlist_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
 292                        &nf_conntrack_hash[hash]);
 293         hlist_add_head(&ct->tuplehash[IP_CT_DIR_REPLY].hnode,
 294                        &nf_conntrack_hash[repl_hash]);
 295 }
 296
 297 void nf_conntrack_hash_insert(struct nf_conn *ct)
 298 {
 299         unsigned int hash, repl_hash;
 300
 301         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 302         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 303
 304         write_lock_bh(&nf_conntrack_lock);
 305         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 306         write_unlock_bh(&nf_conntrack_lock);
 307 }
 308 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 309
 310 /* Confirm a connection given skb; places it in hash table */
 311 int
 312 __nf_conntrack_confirm(struct sk_buff **pskb)
 313 {
 314         unsigned int hash, repl_hash;
 315         struct nf_conntrack_tuple_hash *h;
 316         struct nf_conn *ct;
 317         struct nf_conn_help *help;
 318         struct hlist_node *n;
 319         enum ip_conntrack_info ctinfo;
 320
 321         ct = nf_ct_get(*pskb, &ctinfo);
 322
 323         /* ipt_REJECT uses nf_conntrack_attach to attach related
 324            ICMP/TCP RST packets in other direction.  Actual packet
 325            which created connection will be IP_CT_NEW or for an
 326            expected connection, IP_CT_RELATED. */
 327         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 328                 return NF_ACCEPT;
 329
 330         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 331         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 332
 333         /* We're not in hash table, and we refuse to set up related
 334            connections for unconfirmed conns.  But packet copies and
 335            REJECT will give spurious warnings here. */
 336         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 337
 338         /* No external references means noone else could have
 339            confirmed us. */
 340         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 341         pr_debug("Confirming conntrack %p\n", ct);
 342
 343         write_lock_bh(&nf_conntrack_lock);
 344
 345         /* See if there's one in the list already, including reverse:
 346            NAT could have grabbed it without realizing, since we're
 347            not in the hash.  If there is, we lost race. */
 348         hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode)
 349                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 350                                       &h->tuple))
 351                         goto out;
 352         hlist_for_each_entry(h, n, &nf_conntrack_hash[repl_hash], hnode)
 353                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 354                                       &h->tuple))
 355                         goto out;
 356
 357         /* Remove from unconfirmed list */
 358         hlist_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnode);
 359
 360         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 361         /* Timer relative to confirmation time, not original
 362            setting time, otherwise we'd get timer wrap in
 363            weird delay cases. */
 364         ct->timeout.expires += jiffies;
 365         add_timer(&ct->timeout);
 366         atomic_inc(&ct->ct_general.use);
 367         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 368         NF_CT_STAT_INC(insert);
 369         write_unlock_bh(&nf_conntrack_lock);
 370         help = nfct_help(ct);
 371         if (help && help->helper)
 372                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 373 #ifdef CONFIG_NF_NAT_NEEDED
 374         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 375             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 376                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 377 #endif
 378         nf_conntrack_event_cache(master_ct(ct) ?
 379                                  IPCT_RELATED : IPCT_NEW, *pskb);
 380         return NF_ACCEPT;
 381
 382 out:
 383         NF_CT_STAT_INC(insert_failed);
 384         write_unlock_bh(&nf_conntrack_lock);
 385         return NF_DROP;
 386 }
 387 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 388
 389 /* Returns true if a connection correspondings to the tuple (required
 390    for NAT). */
 391 int
 392 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 393                          const struct nf_conn *ignored_conntrack)
 394 {
 395         struct nf_conntrack_tuple_hash *h;
 396
 397         read_lock_bh(&nf_conntrack_lock);
 398         h = __nf_conntrack_find(tuple, ignored_conntrack);
 399         read_unlock_bh(&nf_conntrack_lock);
 400
 401         return h != NULL;
 402 }
 403 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 404
 405 #define NF_CT_EVICTION_RANGE    8
 406
 407 /* There's a small race here where we may free a just-assured
 408    connection.  Too bad: we're in trouble anyway. */
 409 static int early_drop(unsigned int hash)
 410 {
 411         /* Use oldest entry, which is roughly LRU */
 412         struct nf_conntrack_tuple_hash *h;
 413         struct nf_conn *ct = NULL, *tmp;
 414         struct hlist_node *n;
 415         unsigned int i, cnt = 0;
 416         int dropped = 0;
 417
 418         read_lock_bh(&nf_conntrack_lock);
 419         for (i = 0; i < nf_conntrack_htable_size; i++) {
 420                 hlist_for_each_entry(h, n, &nf_conntrack_hash[hash], hnode) {
 421                         tmp = nf_ct_tuplehash_to_ctrack(h);
 422                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 423                                 ct = tmp;
 424                         cnt++;
 425                 }
 426                 if (ct || cnt >= NF_CT_EVICTION_RANGE)
 427                         break;
 428                 hash = (hash + 1) % nf_conntrack_htable_size;
 429         }
 430         if (ct)
 431                 atomic_inc(&ct->ct_general.use);
 432         read_unlock_bh(&nf_conntrack_lock);
 433
 434         if (!ct)
 435                 return dropped;
 436
 437         if (del_timer(&ct->timeout)) {
 438                 death_by_timeout((unsigned long)ct);
 439                 dropped = 1;
 440                 NF_CT_STAT_INC_ATOMIC(early_drop);
 441         }
 442         nf_ct_put(ct);
 443         return dropped;
 444 }
 445
 446 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 447                                    const struct nf_conntrack_tuple *repl)
 448 {
 449         struct nf_conn *conntrack = NULL;
 450
 451         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 452                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 453                 nf_conntrack_hash_rnd_initted = 1;
 454         }
 455
 456         /* We don't want any race condition at early drop stage */
 457         atomic_inc(&nf_conntrack_count);
 458
 459         if (nf_conntrack_max
 460             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 461                 unsigned int hash = hash_conntrack(orig);
 462                 if (!early_drop(hash)) {
 463                         atomic_dec(&nf_conntrack_count);
 464                         if (net_ratelimit())
 465                                 printk(KERN_WARNING
 466                                        "nf_conntrack: table full, dropping"
 467                                        " packet.\n");
 468                         return ERR_PTR(-ENOMEM);
 469                 }
 470         }
 471
 472         conntrack = kmem_cache_zalloc(nf_conntrack_cachep, GFP_ATOMIC);
 473         if (conntrack == NULL) {
 474                 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
 475                 atomic_dec(&nf_conntrack_count);
 476                 return ERR_PTR(-ENOMEM);
 477         }
 478
 479         atomic_set(&conntrack->ct_general.use, 1);
 480         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 481         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 482         /* Don't set timer yet: wait for confirmation */
 483         setup_timer(&conntrack->timeout, death_by_timeout,
 484                     (unsigned long)conntrack);
 485
 486         return conntrack;
 487 }
 488 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 489
 490 void nf_conntrack_free(struct nf_conn *conntrack)
 491 {
 492         nf_ct_ext_free(conntrack);
 493         kmem_cache_free(nf_conntrack_cachep, conntrack);
 494         atomic_dec(&nf_conntrack_count);
 495 }
 496 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 497
 498 /* Allocate a new conntrack: we return -ENOMEM if classification
 499    failed due to stress.  Otherwise it really is unclassifiable. */
 500 static struct nf_conntrack_tuple_hash *
 501 init_conntrack(const struct nf_conntrack_tuple *tuple,
 502                struct nf_conntrack_l3proto *l3proto,
 503                struct nf_conntrack_l4proto *l4proto,
 504                struct sk_buff *skb,
 505                unsigned int dataoff)
 506 {
 507         struct nf_conn *conntrack;
 508         struct nf_conn_help *help;
 509         struct nf_conntrack_tuple repl_tuple;
 510         struct nf_conntrack_expect *exp;
 511
 512         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 513                 pr_debug("Can't invert tuple.\n");
 514                 return NULL;
 515         }
 516
 517         conntrack = nf_conntrack_alloc(tuple, &repl_tuple);
 518         if (conntrack == NULL || IS_ERR(conntrack)) {
 519                 pr_debug("Can't allocate conntrack.\n");
 520                 return (struct nf_conntrack_tuple_hash *)conntrack;
 521         }
 522
 523         if (!l4proto->new(conntrack, skb, dataoff)) {
 524                 nf_conntrack_free(conntrack);
 525                 pr_debug("init conntrack: can't track with proto module\n");
 526                 return NULL;
 527         }
 528
 529         write_lock_bh(&nf_conntrack_lock);
 530         exp = nf_ct_find_expectation(tuple);
 531         if (exp) {
 532                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 533                          conntrack, exp);
 534                 /* Welcome, Mr. Bond.  We've been expecting you... */
 535                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 536                 conntrack->master = exp->master;
 537                 if (exp->helper) {
 538                         help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC);
 539                         if (help)
 540                                 rcu_assign_pointer(help->helper, exp->helper);
 541                 }
 542
 543 #ifdef CONFIG_NF_CONNTRACK_MARK
 544                 conntrack->mark = exp->master->mark;
 545 #endif
 546 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 547                 conntrack->secmark = exp->master->secmark;
 548 #endif
 549                 nf_conntrack_get(&conntrack->master->ct_general);
 550                 NF_CT_STAT_INC(expect_new);
 551         } else {
 552                 struct nf_conntrack_helper *helper;
 553
 554                 helper = __nf_ct_helper_find(&repl_tuple);
 555                 if (helper) {
 556                         help = nf_ct_helper_ext_add(conntrack, GFP_ATOMIC);
 557                         if (help)
 558                                 rcu_assign_pointer(help->helper, helper);
 559                 }
 560                 NF_CT_STAT_INC(new);
 561         }
 562
 563         /* Overload tuple linked list to put us in unconfirmed list. */
 564         hlist_add_head(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].hnode,
 565                        &unconfirmed);
 566
 567         write_unlock_bh(&nf_conntrack_lock);
 568
 569         if (exp) {
 570                 if (exp->expectfn)
 571                         exp->expectfn(conntrack, exp);
 572                 nf_ct_expect_put(exp);
 573         }
 574
 575         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 576 }
 577
 578 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 579 static inline struct nf_conn *
 580 resolve_normal_ct(struct sk_buff *skb,
 581                   unsigned int dataoff,
 582                   u_int16_t l3num,
 583                   u_int8_t protonum,
 584                   struct nf_conntrack_l3proto *l3proto,
 585                   struct nf_conntrack_l4proto *l4proto,
 586                   int *set_reply,
 587                   enum ip_conntrack_info *ctinfo)
 588 {
 589         struct nf_conntrack_tuple tuple;
 590         struct nf_conntrack_tuple_hash *h;
 591         struct nf_conn *ct;
 592
 593         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 594                              dataoff, l3num, protonum, &tuple, l3proto,
 595                              l4proto)) {
 596                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 597                 return NULL;
 598         }
 599
 600         /* look for tuple match */
 601         h = nf_conntrack_find_get(&tuple);
 602         if (!h) {
 603                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 604                 if (!h)
 605                         return NULL;
 606                 if (IS_ERR(h))
 607                         return (void *)h;
 608         }
 609         ct = nf_ct_tuplehash_to_ctrack(h);
 610
 611         /* It exists; we have (non-exclusive) reference. */
 612         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 613                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 614                 /* Please set reply bit if this packet OK */
 615                 *set_reply = 1;
 616         } else {
 617                 /* Once we've had two way comms, always ESTABLISHED. */
 618                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 619                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 620                         *ctinfo = IP_CT_ESTABLISHED;
 621                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 622                         pr_debug("nf_conntrack_in: related packet for %p\n",
 623                                  ct);
 624                         *ctinfo = IP_CT_RELATED;
 625                 } else {
 626                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 627                         *ctinfo = IP_CT_NEW;
 628                 }
 629                 *set_reply = 0;
 630         }
 631         skb->nfct = &ct->ct_general;
 632         skb->nfctinfo = *ctinfo;
 633         return ct;
 634 }
 635
 636 unsigned int
 637 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 638 {
 639         struct nf_conn *ct;
 640         enum ip_conntrack_info ctinfo;
 641         struct nf_conntrack_l3proto *l3proto;
 642         struct nf_conntrack_l4proto *l4proto;
 643         unsigned int dataoff;
 644         u_int8_t protonum;
 645         int set_reply = 0;
 646         int ret;
 647
 648         /* Previously seen (loopback or untracked)?  Ignore. */
 649         if ((*pskb)->nfct) {
 650                 NF_CT_STAT_INC_ATOMIC(ignore);
 651                 return NF_ACCEPT;
 652         }
 653
 654         /* rcu_read_lock()ed by nf_hook_slow */
 655         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 656         ret = l3proto->get_l4proto(*pskb, skb_network_offset(*pskb),
 657                                    &dataoff, &protonum);
 658         if (ret <= 0) {
 659                 pr_debug("not prepared to track yet or error occured\n");
 660                 NF_CT_STAT_INC_ATOMIC(error);
 661                 NF_CT_STAT_INC_ATOMIC(invalid);
 662                 return -ret;
 663         }
 664
 665         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
 666
 667         /* It may be an special packet, error, unclean...
 668          * inverse of the return code tells to the netfilter
 669          * core what to do with the packet. */
 670         if (l4proto->error != NULL &&
 671             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 672                 NF_CT_STAT_INC_ATOMIC(error);
 673                 NF_CT_STAT_INC_ATOMIC(invalid);
 674                 return -ret;
 675         }
 676
 677         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
 678                                &set_reply, &ctinfo);
 679         if (!ct) {
 680                 /* Not valid part of a connection */
 681                 NF_CT_STAT_INC_ATOMIC(invalid);
 682                 return NF_ACCEPT;
 683         }
 684
 685         if (IS_ERR(ct)) {
 686                 /* Too stressed to deal. */
 687                 NF_CT_STAT_INC_ATOMIC(drop);
 688                 return NF_DROP;
 689         }
 690
 691         NF_CT_ASSERT((*pskb)->nfct);
 692
 693         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
 694         if (ret < 0) {
 695                 /* Invalid: inverse of the return code tells
 696                  * the netfilter core what to do */
 697                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
 698                 nf_conntrack_put((*pskb)->nfct);
 699                 (*pskb)->nfct = NULL;
 700                 NF_CT_STAT_INC_ATOMIC(invalid);
 701                 return -ret;
 702         }
 703
 704         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 705                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
 706
 707         return ret;
 708 }
 709 EXPORT_SYMBOL_GPL(nf_conntrack_in);
 710
 711 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 712                          const struct nf_conntrack_tuple *orig)
 713 {
 714         int ret;
 715
 716         rcu_read_lock();
 717         ret = nf_ct_invert_tuple(inverse, orig,
 718                                  __nf_ct_l3proto_find(orig->src.l3num),
 719                                  __nf_ct_l4proto_find(orig->src.l3num,
 720                                                       orig->dst.protonum));
 721         rcu_read_unlock();
 722         return ret;
 723 }
 724 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 725
 726 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 727    implicitly racy: see __nf_conntrack_confirm */
 728 void nf_conntrack_alter_reply(struct nf_conn *ct,
 729                               const struct nf_conntrack_tuple *newreply)
 730 {
 731         struct nf_conn_help *help = nfct_help(ct);
 732         struct nf_conntrack_helper *helper;
 733
 734         write_lock_bh(&nf_conntrack_lock);
 735         /* Should be unconfirmed, so not in hash table yet */
 736         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 737
 738         pr_debug("Altering reply tuple of %p to ", ct);
 739         NF_CT_DUMP_TUPLE(newreply);
 740
 741         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 742         if (ct->master || (help && help->expecting != 0))
 743                 goto out;
 744
 745         helper = __nf_ct_helper_find(newreply);
 746         if (helper == NULL) {
 747                 if (help)
 748                         rcu_assign_pointer(help->helper, NULL);
 749                 goto out;
 750         }
 751
 752         if (help == NULL) {
 753                 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
 754                 if (help == NULL)
 755                         goto out;
 756         } else {
 757                 memset(&help->help, 0, sizeof(help->help));
 758         }
 759
 760         rcu_assign_pointer(help->helper, helper);
 761 out:
 762         write_unlock_bh(&nf_conntrack_lock);
 763 }
 764 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 765
 766 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 767 void __nf_ct_refresh_acct(struct nf_conn *ct,
 768                           enum ip_conntrack_info ctinfo,
 769                           const struct sk_buff *skb,
 770                           unsigned long extra_jiffies,
 771                           int do_acct)
 772 {
 773         int event = 0;
 774
 775         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 776         NF_CT_ASSERT(skb);
 777
 778         write_lock_bh(&nf_conntrack_lock);
 779
 780         /* Only update if this is not a fixed timeout */
 781         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 782                 write_unlock_bh(&nf_conntrack_lock);
 783                 return;
 784         }
 785
 786         /* If not in hash table, timer will not be active yet */
 787         if (!nf_ct_is_confirmed(ct)) {
 788                 ct->timeout.expires = extra_jiffies;
 789                 event = IPCT_REFRESH;
 790         } else {
 791                 unsigned long newtime = jiffies + extra_jiffies;
 792
 793                 /* Only update the timeout if the new timeout is at least
 794                    HZ jiffies from the old timeout. Need del_timer for race
 795                    avoidance (may already be dying). */
 796                 if (newtime - ct->timeout.expires >= HZ
 797                     && del_timer(&ct->timeout)) {
 798                         ct->timeout.expires = newtime;
 799                         add_timer(&ct->timeout);
 800                         event = IPCT_REFRESH;
 801                 }
 802         }
 803
 804 #ifdef CONFIG_NF_CT_ACCT
 805         if (do_acct) {
 806                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 807                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 808                         skb->len - skb_network_offset(skb);
 809
 810                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 811                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 812                         event |= IPCT_COUNTER_FILLING;
 813         }
 814 #endif
 815
 816         write_unlock_bh(&nf_conntrack_lock);
 817
 818         /* must be unlocked when calling event cache */
 819         if (event)
 820                 nf_conntrack_event_cache(event, skb);
 821 }
 822 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 823
 824 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 825
 826 #include <linux/netfilter/nfnetlink.h>
 827 #include <linux/netfilter/nfnetlink_conntrack.h>
 828 #include <linux/mutex.h>
 829
 830 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 831  * in ip_conntrack_core, since we don't want the protocols to autoload
 832  * or depend on ctnetlink */
 833 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
 834                                const struct nf_conntrack_tuple *tuple)
 835 {
 836         NLA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
 837                 &tuple->src.u.tcp.port);
 838         NLA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
 839                 &tuple->dst.u.tcp.port);
 840         return 0;
 841
 842 nla_put_failure:
 843         return -1;
 844 }
 845 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
 846
 847 static const size_t cta_min_proto[CTA_PROTO_MAX+1] = {
 848         [CTA_PROTO_SRC_PORT]  = sizeof(u_int16_t),
 849         [CTA_PROTO_DST_PORT]  = sizeof(u_int16_t)
 850 };
 851
 852 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
 853                                struct nf_conntrack_tuple *t)
 854 {
 855         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
 856                 return -EINVAL;
 857
 858         if (nlattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
 859                 return -EINVAL;
 860
 861         t->src.u.tcp.port = *(__be16 *)nla_data(tb[CTA_PROTO_SRC_PORT]);
 862         t->dst.u.tcp.port = *(__be16 *)nla_data(tb[CTA_PROTO_DST_PORT]);
 863
 864         return 0;
 865 }
 866 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
 867 #endif
 868
 869 /* Used by ipt_REJECT and ip6t_REJECT. */
 870 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
 871 {
 872         struct nf_conn *ct;
 873         enum ip_conntrack_info ctinfo;
 874
 875         /* This ICMP is in reverse direction to the packet which caused it */
 876         ct = nf_ct_get(skb, &ctinfo);
 877         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
 878                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
 879         else
 880                 ctinfo = IP_CT_RELATED;
 881
 882         /* Attach to new skbuff, and increment count */
 883         nskb->nfct = &ct->ct_general;
 884         nskb->nfctinfo = ctinfo;
 885         nf_conntrack_get(nskb->nfct);
 886 }
 887 EXPORT_SYMBOL_GPL(__nf_conntrack_attach);
 888
 889 static inline int
 890 do_iter(const struct nf_conntrack_tuple_hash *i,
 891         int (*iter)(struct nf_conn *i, void *data),
 892         void *data)
 893 {
 894         return iter(nf_ct_tuplehash_to_ctrack(i), data);
 895 }
 896
 897 /* Bring out ya dead! */
 898 static struct nf_conn *
 899 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
 900                 void *data, unsigned int *bucket)
 901 {
 902         struct nf_conntrack_tuple_hash *h;
 903         struct nf_conn *ct;
 904         struct hlist_node *n;
 905
 906         write_lock_bh(&nf_conntrack_lock);
 907         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
 908                 hlist_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnode) {
 909                         ct = nf_ct_tuplehash_to_ctrack(h);
 910                         if (iter(ct, data))
 911                                 goto found;
 912                 }
 913         }
 914         hlist_for_each_entry(h, n, &unconfirmed, hnode) {
 915                 ct = nf_ct_tuplehash_to_ctrack(h);
 916                 if (iter(ct, data))
 917                         set_bit(IPS_DYING_BIT, &ct->status);
 918         }
 919         write_unlock_bh(&nf_conntrack_lock);
 920         return NULL;
 921 found:
 922         atomic_inc(&ct->ct_general.use);
 923         write_unlock_bh(&nf_conntrack_lock);
 924         return ct;
 925 }
 926
 927 void
 928 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
 929 {
 930         struct nf_conn *ct;
 931         unsigned int bucket = 0;
 932
 933         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
 934                 /* Time to push up daises... */
 935                 if (del_timer(&ct->timeout))
 936                         death_by_timeout((unsigned long)ct);
 937                 /* ... else the timer will get him soon. */
 938
 939                 nf_ct_put(ct);
 940         }
 941 }
 942 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
 943
 944 static int kill_all(struct nf_conn *i, void *data)
 945 {
 946         return 1;
 947 }
 948
 949 void nf_ct_free_hashtable(struct hlist_head *hash, int vmalloced, int size)
 950 {
 951         if (vmalloced)
 952                 vfree(hash);
 953         else
 954                 free_pages((unsigned long)hash,
 955                            get_order(sizeof(struct hlist_head) * size));
 956 }
 957 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
 958
 959 void nf_conntrack_flush(void)
 960 {
 961         nf_ct_iterate_cleanup(kill_all, NULL);
 962 }
 963 EXPORT_SYMBOL_GPL(nf_conntrack_flush);
 964
 965 /* Mishearing the voices in his head, our hero wonders how he's
 966    supposed to kill the mall. */
 967 void nf_conntrack_cleanup(void)
 968 {
 969         rcu_assign_pointer(ip_ct_attach, NULL);
 970
 971         /* This makes sure all current packets have passed through
 972            netfilter framework.  Roll on, two-stage module
 973            delete... */
 974         synchronize_net();
 975
 976         nf_ct_event_cache_flush();
 977  i_see_dead_people:
 978         nf_conntrack_flush();
 979         if (atomic_read(&nf_conntrack_count) != 0) {
 980                 schedule();
 981                 goto i_see_dead_people;
 982         }
 983         /* wait until all references to nf_conntrack_untracked are dropped */
 984         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
 985                 schedule();
 986
 987         rcu_assign_pointer(nf_ct_destroy, NULL);
 988
 989         kmem_cache_destroy(nf_conntrack_cachep);
 990         nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
 991                              nf_conntrack_htable_size);
 992
 993         nf_conntrack_proto_fini();
 994         nf_conntrack_helper_fini();
 995         nf_conntrack_expect_fini();
 996 }
 997
 998 struct hlist_head *nf_ct_alloc_hashtable(int *sizep, int *vmalloced)
 999 {
1000         struct hlist_head *hash;
1001         unsigned int size, i;
1002
1003         *vmalloced = 0;
1004
1005         size = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_head));
1006         hash = (void*)__get_free_pages(GFP_KERNEL,
1007                                        get_order(sizeof(struct hlist_head)
1008                                                  * size));
1009         if (!hash) {
1010                 *vmalloced = 1;
1011                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1012                 hash = vmalloc(sizeof(struct hlist_head) * size);
1013         }
1014
1015         if (hash)
1016                 for (i = 0; i < size; i++)
1017                         INIT_HLIST_HEAD(&hash[i]);
1018
1019         return hash;
1020 }
1021 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1022
1023 int set_hashsize(const char *val, struct kernel_param *kp)
1024 {
1025         int i, bucket, hashsize, vmalloced;
1026         int old_vmalloced, old_size;
1027         int rnd;
1028         struct hlist_head *hash, *old_hash;
1029         struct nf_conntrack_tuple_hash *h;
1030
1031         /* On boot, we can set this without any fancy locking. */
1032         if (!nf_conntrack_htable_size)
1033                 return param_set_uint(val, kp);
1034
1035         hashsize = simple_strtol(val, NULL, 0);
1036         if (!hashsize)
1037                 return -EINVAL;
1038
1039         hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced);
1040         if (!hash)
1041                 return -ENOMEM;
1042
1043         /* We have to rehahs for the new table anyway, so we also can
1044          * use a newrandom seed */
1045         get_random_bytes(&rnd, 4);
1046
1047         write_lock_bh(&nf_conntrack_lock);
1048         for (i = 0; i < nf_conntrack_htable_size; i++) {
1049                 while (!hlist_empty(&nf_conntrack_hash[i])) {
1050                         h = hlist_entry(nf_conntrack_hash[i].first,
1051                                         struct nf_conntrack_tuple_hash, hnode);
1052                         hlist_del(&h->hnode);
1053                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1054                         hlist_add_head(&h->hnode, &hash[bucket]);
1055                 }
1056         }
1057         old_size = nf_conntrack_htable_size;
1058         old_vmalloced = nf_conntrack_vmalloc;
1059         old_hash = nf_conntrack_hash;
1060
1061         nf_conntrack_htable_size = hashsize;
1062         nf_conntrack_vmalloc = vmalloced;
1063         nf_conntrack_hash = hash;
1064         nf_conntrack_hash_rnd = rnd;
1065         write_unlock_bh(&nf_conntrack_lock);
1066
1067         nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1068         return 0;
1069 }
1070
1071 module_param_call(hashsize, set_hashsize, param_get_uint,
1072                   &nf_conntrack_htable_size, 0600);
1073
1074 int __init nf_conntrack_init(void)
1075 {
1076         int max_factor = 8;
1077         int ret;
1078
1079         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1080          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1081         if (!nf_conntrack_htable_size) {
1082                 nf_conntrack_htable_size
1083                         = (((num_physpages << PAGE_SHIFT) / 16384)
1084                            / sizeof(struct hlist_head));
1085                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1086                         nf_conntrack_htable_size = 16384;
1087                 if (nf_conntrack_htable_size < 32)
1088                         nf_conntrack_htable_size = 32;
1089
1090                 /* Use a max. factor of four by default to get the same max as
1091                  * with the old struct list_heads. When a table size is given
1092                  * we use the old value of 8 to avoid reducing the max.
1093                  * entries. */
1094                 max_factor = 4;
1095         }
1096         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1097                                                   &nf_conntrack_vmalloc);
1098         if (!nf_conntrack_hash) {
1099                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1100                 goto err_out;
1101         }
1102
1103         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1104
1105         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1106                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1107                nf_conntrack_max);
1108
1109         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1110                                                 sizeof(struct nf_conn),
1111                                                 0, 0, NULL);
1112         if (!nf_conntrack_cachep) {
1113                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1114                 goto err_free_hash;
1115         }
1116
1117         ret = nf_conntrack_proto_init();
1118         if (ret < 0)
1119                 goto err_free_conntrack_slab;
1120
1121         ret = nf_conntrack_expect_init();
1122         if (ret < 0)
1123                 goto out_fini_proto;
1124
1125         ret = nf_conntrack_helper_init();
1126         if (ret < 0)
1127                 goto out_fini_expect;
1128
1129         /* For use by REJECT target */
1130         rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
1131         rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1132
1133         /* Set up fake conntrack:
1134             - to never be deleted, not in any hashes */
1135         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1136         /*  - and look it like as a confirmed connection */
1137         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1138
1139         return ret;
1140
1141 out_fini_expect:
1142         nf_conntrack_expect_fini();
1143 out_fini_proto:
1144         nf_conntrack_proto_fini();
1145 err_free_conntrack_slab:
1146         kmem_cache_destroy(nf_conntrack_cachep);
1147 err_free_hash:
1148         nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_vmalloc,
1149                              nf_conntrack_htable_size);
1150 err_out:
1151         return -ENOMEM;
1152 }