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  * (C) 2005-2012 Patrick McHardy <kaber@trash.net>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/types.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/stddef.h>
  23 #include <linux/slab.h>
  24 #include <linux/random.h>
  25 #include <linux/jhash.h>
  26 #include <linux/err.h>
  27 #include <linux/percpu.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/notifier.h>
  30 #include <linux/kernel.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/socket.h>
  33 #include <linux/mm.h>
  34 #include <linux/nsproxy.h>
  35 #include <linux/rculist_nulls.h>
  36
  37 #include <net/netfilter/nf_conntrack.h>
  38 #include <net/netfilter/nf_conntrack_l3proto.h>
  39 #include <net/netfilter/nf_conntrack_l4proto.h>
  40 #include <net/netfilter/nf_conntrack_expect.h>
  41 #include <net/netfilter/nf_conntrack_helper.h>
  42 #include <net/netfilter/nf_conntrack_seqadj.h>
  43 #include <net/netfilter/nf_conntrack_core.h>
  44 #include <net/netfilter/nf_conntrack_extend.h>
  45 #include <net/netfilter/nf_conntrack_acct.h>
  46 #include <net/netfilter/nf_conntrack_ecache.h>
  47 #include <net/netfilter/nf_conntrack_zones.h>
  48 #include <net/netfilter/nf_conntrack_timestamp.h>
  49 #include <net/netfilter/nf_conntrack_timeout.h>
  50 #include <net/netfilter/nf_conntrack_labels.h>
  51 #include <net/netfilter/nf_conntrack_synproxy.h>
  52 #include <net/netfilter/nf_nat.h>
  53 #include <net/netfilter/nf_nat_core.h>
  54 #include <net/netfilter/nf_nat_helper.h>
  55
  56 #define NF_CONNTRACK_VERSION    "0.5.0"
  57
  58 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
  59                                       enum nf_nat_manip_type manip,
  60                                       const struct nlattr *attr) __read_mostly;
  61 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
  62
  63 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
  64 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
  65
  66 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
  67 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
  68
  69 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
  70 {
  71         h1 %= CONNTRACK_LOCKS;
  72         h2 %= CONNTRACK_LOCKS;
  73         spin_unlock(&nf_conntrack_locks[h1]);
  74         if (h1 != h2)
  75                 spin_unlock(&nf_conntrack_locks[h2]);
  76 }
  77
  78 /* return true if we need to recompute hashes (in case hash table was resized) */
  79 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
  80                                      unsigned int h2, unsigned int sequence)
  81 {
  82         h1 %= CONNTRACK_LOCKS;
  83         h2 %= CONNTRACK_LOCKS;
  84         if (h1 <= h2) {
  85                 spin_lock(&nf_conntrack_locks[h1]);
  86                 if (h1 != h2)
  87                         spin_lock_nested(&nf_conntrack_locks[h2],
  88                                          SINGLE_DEPTH_NESTING);
  89         } else {
  90                 spin_lock(&nf_conntrack_locks[h2]);
  91                 spin_lock_nested(&nf_conntrack_locks[h1],
  92                                  SINGLE_DEPTH_NESTING);
  93         }
  94         if (read_seqcount_retry(&net->ct.generation, sequence)) {
  95                 nf_conntrack_double_unlock(h1, h2);
  96                 return true;
  97         }
  98         return false;
  99 }
 100
 101 static void nf_conntrack_all_lock(void)
 102 {
 103         int i;
 104
 105         for (i = 0; i < CONNTRACK_LOCKS; i++)
 106                 spin_lock_nested(&nf_conntrack_locks[i], i);
 107 }
 108
 109 static void nf_conntrack_all_unlock(void)
 110 {
 111         int i;
 112
 113         for (i = 0; i < CONNTRACK_LOCKS; i++)
 114                 spin_unlock(&nf_conntrack_locks[i]);
 115 }
 116
 117 unsigned int nf_conntrack_htable_size __read_mostly;
 118 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
 119
 120 unsigned int nf_conntrack_max __read_mostly;
 121 EXPORT_SYMBOL_GPL(nf_conntrack_max);
 122
 123 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
 124 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
 125
 126 unsigned int nf_conntrack_hash_rnd __read_mostly;
 127 EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd);
 128
 129 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple)
 130 {
 131         unsigned int n;
 132
 133         /* The direction must be ignored, so we hash everything up to the
 134          * destination ports (which is a multiple of 4) and treat the last
 135          * three bytes manually.
 136          */
 137         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
 138         return jhash2((u32 *)tuple, n, nf_conntrack_hash_rnd ^
 139                       (((__force __u16)tuple->dst.u.all << 16) |
 140                       tuple->dst.protonum));
 141 }
 142
 143 static u32 __hash_bucket(u32 hash, unsigned int size)
 144 {
 145         return reciprocal_scale(hash, size);
 146 }
 147
 148 static u32 hash_bucket(u32 hash, const struct net *net)
 149 {
 150         return __hash_bucket(hash, net->ct.htable_size);
 151 }
 152
 153 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 154                                   unsigned int size)
 155 {
 156         return __hash_bucket(hash_conntrack_raw(tuple), size);
 157 }
 158
 159 static inline u_int32_t hash_conntrack(const struct net *net,
 160                                        const struct nf_conntrack_tuple *tuple)
 161 {
 162         return __hash_conntrack(tuple, net->ct.htable_size);
 163 }
 164
 165 bool
 166 nf_ct_get_tuple(const struct sk_buff *skb,
 167                 unsigned int nhoff,
 168                 unsigned int dataoff,
 169                 u_int16_t l3num,
 170                 u_int8_t protonum,
 171                 struct nf_conntrack_tuple *tuple,
 172                 const struct nf_conntrack_l3proto *l3proto,
 173                 const struct nf_conntrack_l4proto *l4proto)
 174 {
 175         memset(tuple, 0, sizeof(*tuple));
 176
 177         tuple->src.l3num = l3num;
 178         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 179                 return false;
 180
 181         tuple->dst.protonum = protonum;
 182         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 183
 184         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 185 }
 186 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 187
 188 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 189                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
 190 {
 191         struct nf_conntrack_l3proto *l3proto;
 192         struct nf_conntrack_l4proto *l4proto;
 193         unsigned int protoff;
 194         u_int8_t protonum;
 195         int ret;
 196
 197         rcu_read_lock();
 198
 199         l3proto = __nf_ct_l3proto_find(l3num);
 200         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 201         if (ret != NF_ACCEPT) {
 202                 rcu_read_unlock();
 203                 return false;
 204         }
 205
 206         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 207
 208         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 209                               l3proto, l4proto);
 210
 211         rcu_read_unlock();
 212         return ret;
 213 }
 214 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 215
 216 bool
 217 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 218                    const struct nf_conntrack_tuple *orig,
 219                    const struct nf_conntrack_l3proto *l3proto,
 220                    const struct nf_conntrack_l4proto *l4proto)
 221 {
 222         memset(inverse, 0, sizeof(*inverse));
 223
 224         inverse->src.l3num = orig->src.l3num;
 225         if (l3proto->invert_tuple(inverse, orig) == 0)
 226                 return false;
 227
 228         inverse->dst.dir = !orig->dst.dir;
 229
 230         inverse->dst.protonum = orig->dst.protonum;
 231         return l4proto->invert_tuple(inverse, orig);
 232 }
 233 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 234
 235 static void
 236 clean_from_lists(struct nf_conn *ct)
 237 {
 238         pr_debug("clean_from_lists(%p)\n", ct);
 239         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 240         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 241
 242         /* Destroy all pending expectations */
 243         nf_ct_remove_expectations(ct);
 244 }
 245
 246 /* must be called with local_bh_disable */
 247 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
 248 {
 249         struct ct_pcpu *pcpu;
 250
 251         /* add this conntrack to the (per cpu) dying list */
 252         ct->cpu = smp_processor_id();
 253         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 254
 255         spin_lock(&pcpu->lock);
 256         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 257                              &pcpu->dying);
 258         spin_unlock(&pcpu->lock);
 259 }
 260
 261 /* must be called with local_bh_disable */
 262 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
 263 {
 264         struct ct_pcpu *pcpu;
 265
 266         /* add this conntrack to the (per cpu) unconfirmed list */
 267         ct->cpu = smp_processor_id();
 268         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 269
 270         spin_lock(&pcpu->lock);
 271         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 272                              &pcpu->unconfirmed);
 273         spin_unlock(&pcpu->lock);
 274 }
 275
 276 /* must be called with local_bh_disable */
 277 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
 278 {
 279         struct ct_pcpu *pcpu;
 280
 281         /* We overload first tuple to link into unconfirmed or dying list.*/
 282         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 283
 284         spin_lock(&pcpu->lock);
 285         BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 286         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 287         spin_unlock(&pcpu->lock);
 288 }
 289
 290 /* Released via destroy_conntrack() */
 291 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 292                                  const struct nf_conntrack_zone *zone,
 293                                  gfp_t flags)
 294 {
 295         struct nf_conn *tmpl;
 296
 297         tmpl = kzalloc(sizeof(*tmpl), flags);
 298         if (tmpl == NULL)
 299                 return NULL;
 300
 301         tmpl->status = IPS_TEMPLATE;
 302         write_pnet(&tmpl->ct_net, net);
 303
 304         if (nf_ct_zone_add(tmpl, flags, zone) < 0)
 305                 goto out_free;
 306
 307         atomic_set(&tmpl->ct_general.use, 0);
 308
 309         return tmpl;
 310 out_free:
 311         kfree(tmpl);
 312         return NULL;
 313 }
 314 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
 315
 316 static void nf_ct_tmpl_free(struct nf_conn *tmpl)
 317 {
 318         nf_ct_ext_destroy(tmpl);
 319         nf_ct_ext_free(tmpl);
 320         kfree(tmpl);
 321 }
 322
 323 static void
 324 destroy_conntrack(struct nf_conntrack *nfct)
 325 {
 326         struct nf_conn *ct = (struct nf_conn *)nfct;
 327         struct net *net = nf_ct_net(ct);
 328         struct nf_conntrack_l4proto *l4proto;
 329
 330         pr_debug("destroy_conntrack(%p)\n", ct);
 331         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 332         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 333
 334         if (unlikely(nf_ct_is_template(ct))) {
 335                 nf_ct_tmpl_free(ct);
 336                 return;
 337         }
 338         rcu_read_lock();
 339         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 340         if (l4proto && l4proto->destroy)
 341                 l4proto->destroy(ct);
 342
 343         rcu_read_unlock();
 344
 345         local_bh_disable();
 346         /* Expectations will have been removed in clean_from_lists,
 347          * except TFTP can create an expectation on the first packet,
 348          * before connection is in the list, so we need to clean here,
 349          * too.
 350          */
 351         nf_ct_remove_expectations(ct);
 352
 353         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 354
 355         NF_CT_STAT_INC(net, delete);
 356         local_bh_enable();
 357
 358         if (ct->master)
 359                 nf_ct_put(ct->master);
 360
 361         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 362         nf_conntrack_free(ct);
 363 }
 364
 365 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 366 {
 367         struct net *net = nf_ct_net(ct);
 368         unsigned int hash, reply_hash;
 369         unsigned int sequence;
 370
 371         nf_ct_helper_destroy(ct);
 372
 373         local_bh_disable();
 374         do {
 375                 sequence = read_seqcount_begin(&net->ct.generation);
 376                 hash = hash_conntrack(net,
 377                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 378                 reply_hash = hash_conntrack(net,
 379                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 380         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 381
 382         clean_from_lists(ct);
 383         nf_conntrack_double_unlock(hash, reply_hash);
 384
 385         nf_ct_add_to_dying_list(ct);
 386
 387         NF_CT_STAT_INC(net, delete_list);
 388         local_bh_enable();
 389 }
 390
 391 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 392 {
 393         struct nf_conn_tstamp *tstamp;
 394
 395         tstamp = nf_conn_tstamp_find(ct);
 396         if (tstamp && tstamp->stop == 0)
 397                 tstamp->stop = ktime_get_real_ns();
 398
 399         if (nf_ct_is_dying(ct))
 400                 goto delete;
 401
 402         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 403                                     portid, report) < 0) {
 404                 /* destroy event was not delivered */
 405                 nf_ct_delete_from_lists(ct);
 406                 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
 407                 return false;
 408         }
 409
 410         nf_conntrack_ecache_work(nf_ct_net(ct));
 411         set_bit(IPS_DYING_BIT, &ct->status);
 412  delete:
 413         nf_ct_delete_from_lists(ct);
 414         nf_ct_put(ct);
 415         return true;
 416 }
 417 EXPORT_SYMBOL_GPL(nf_ct_delete);
 418
 419 static void death_by_timeout(unsigned long ul_conntrack)
 420 {
 421         nf_ct_delete((struct nf_conn *)ul_conntrack, 0, 0);
 422 }
 423
 424 static inline bool
 425 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 426                 const struct nf_conntrack_tuple *tuple,
 427                 const struct nf_conntrack_zone *zone)
 428 {
 429         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 430
 431         /* A conntrack can be recreated with the equal tuple,
 432          * so we need to check that the conntrack is confirmed
 433          */
 434         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 435                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 436                nf_ct_is_confirmed(ct);
 437 }
 438
 439 /*
 440  * Warning :
 441  * - Caller must take a reference on returned object
 442  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 443  */
 444 static struct nf_conntrack_tuple_hash *
 445 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 446                       const struct nf_conntrack_tuple *tuple, u32 hash)
 447 {
 448         struct nf_conntrack_tuple_hash *h;
 449         struct hlist_nulls_node *n;
 450         unsigned int bucket = hash_bucket(hash, net);
 451
 452         /* Disable BHs the entire time since we normally need to disable them
 453          * at least once for the stats anyway.
 454          */
 455         local_bh_disable();
 456 begin:
 457         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
 458                 if (nf_ct_key_equal(h, tuple, zone)) {
 459                         NF_CT_STAT_INC(net, found);
 460                         local_bh_enable();
 461                         return h;
 462                 }
 463                 NF_CT_STAT_INC(net, searched);
 464         }
 465         /*
 466          * if the nulls value we got at the end of this lookup is
 467          * not the expected one, we must restart lookup.
 468          * We probably met an item that was moved to another chain.
 469          */
 470         if (get_nulls_value(n) != bucket) {
 471                 NF_CT_STAT_INC(net, search_restart);
 472                 goto begin;
 473         }
 474         local_bh_enable();
 475
 476         return NULL;
 477 }
 478
 479 /* Find a connection corresponding to a tuple. */
 480 static struct nf_conntrack_tuple_hash *
 481 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 482                         const struct nf_conntrack_tuple *tuple, u32 hash)
 483 {
 484         struct nf_conntrack_tuple_hash *h;
 485         struct nf_conn *ct;
 486
 487         rcu_read_lock();
 488 begin:
 489         h = ____nf_conntrack_find(net, zone, tuple, hash);
 490         if (h) {
 491                 ct = nf_ct_tuplehash_to_ctrack(h);
 492                 if (unlikely(nf_ct_is_dying(ct) ||
 493                              !atomic_inc_not_zero(&ct->ct_general.use)))
 494                         h = NULL;
 495                 else {
 496                         if (unlikely(!nf_ct_key_equal(h, tuple, zone))) {
 497                                 nf_ct_put(ct);
 498                                 goto begin;
 499                         }
 500                 }
 501         }
 502         rcu_read_unlock();
 503
 504         return h;
 505 }
 506
 507 struct nf_conntrack_tuple_hash *
 508 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 509                       const struct nf_conntrack_tuple *tuple)
 510 {
 511         return __nf_conntrack_find_get(net, zone, tuple,
 512                                        hash_conntrack_raw(tuple));
 513 }
 514 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 515
 516 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 517                                        unsigned int hash,
 518                                        unsigned int reply_hash)
 519 {
 520         struct net *net = nf_ct_net(ct);
 521
 522         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 523                            &net->ct.hash[hash]);
 524         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 525                            &net->ct.hash[reply_hash]);
 526 }
 527
 528 int
 529 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 530 {
 531         const struct nf_conntrack_zone *zone;
 532         struct net *net = nf_ct_net(ct);
 533         unsigned int hash, reply_hash;
 534         struct nf_conntrack_tuple_hash *h;
 535         struct hlist_nulls_node *n;
 536         unsigned int sequence;
 537
 538         zone = nf_ct_zone(ct);
 539
 540         local_bh_disable();
 541         do {
 542                 sequence = read_seqcount_begin(&net->ct.generation);
 543                 hash = hash_conntrack(net,
 544                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 545                 reply_hash = hash_conntrack(net,
 546                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 547         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 548
 549         /* See if there's one in the list already, including reverse */
 550         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 551                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 552                                       &h->tuple) &&
 553                     nf_ct_zone_equal(nf_ct_tuplehash_to_ctrack(h), zone,
 554                                      NF_CT_DIRECTION(h)))
 555                         goto out;
 556         hlist_nulls_for_each_entry(h, n, &net->ct.hash[reply_hash], hnnode)
 557                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 558                                       &h->tuple) &&
 559                     nf_ct_zone_equal(nf_ct_tuplehash_to_ctrack(h), zone,
 560                                      NF_CT_DIRECTION(h)))
 561                         goto out;
 562
 563         add_timer(&ct->timeout);
 564         smp_wmb();
 565         /* The caller holds a reference to this object */
 566         atomic_set(&ct->ct_general.use, 2);
 567         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 568         nf_conntrack_double_unlock(hash, reply_hash);
 569         NF_CT_STAT_INC(net, insert);
 570         local_bh_enable();
 571         return 0;
 572
 573 out:
 574         nf_conntrack_double_unlock(hash, reply_hash);
 575         NF_CT_STAT_INC(net, insert_failed);
 576         local_bh_enable();
 577         return -EEXIST;
 578 }
 579 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 580
 581 /* Confirm a connection given skb; places it in hash table */
 582 int
 583 __nf_conntrack_confirm(struct sk_buff *skb)
 584 {
 585         const struct nf_conntrack_zone *zone;
 586         unsigned int hash, reply_hash;
 587         struct nf_conntrack_tuple_hash *h;
 588         struct nf_conn *ct;
 589         struct nf_conn_help *help;
 590         struct nf_conn_tstamp *tstamp;
 591         struct hlist_nulls_node *n;
 592         enum ip_conntrack_info ctinfo;
 593         struct net *net;
 594         unsigned int sequence;
 595
 596         ct = nf_ct_get(skb, &ctinfo);
 597         net = nf_ct_net(ct);
 598
 599         /* ipt_REJECT uses nf_conntrack_attach to attach related
 600            ICMP/TCP RST packets in other direction.  Actual packet
 601            which created connection will be IP_CT_NEW or for an
 602            expected connection, IP_CT_RELATED. */
 603         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 604                 return NF_ACCEPT;
 605
 606         zone = nf_ct_zone(ct);
 607         local_bh_disable();
 608
 609         do {
 610                 sequence = read_seqcount_begin(&net->ct.generation);
 611                 /* reuse the hash saved before */
 612                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 613                 hash = hash_bucket(hash, net);
 614                 reply_hash = hash_conntrack(net,
 615                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 616
 617         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 618
 619         /* We're not in hash table, and we refuse to set up related
 620          * connections for unconfirmed conns.  But packet copies and
 621          * REJECT will give spurious warnings here.
 622          */
 623         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 624
 625         /* No external references means no one else could have
 626          * confirmed us.
 627          */
 628         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 629         pr_debug("Confirming conntrack %p\n", ct);
 630         /* We have to check the DYING flag after unlink to prevent
 631          * a race against nf_ct_get_next_corpse() possibly called from
 632          * user context, else we insert an already 'dead' hash, blocking
 633          * further use of that particular connection -JM.
 634          */
 635         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 636
 637         if (unlikely(nf_ct_is_dying(ct)))
 638                 goto out;
 639
 640         /* See if there's one in the list already, including reverse:
 641            NAT could have grabbed it without realizing, since we're
 642            not in the hash.  If there is, we lost race. */
 643         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 644                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 645                                       &h->tuple) &&
 646                     nf_ct_zone_equal(nf_ct_tuplehash_to_ctrack(h), zone,
 647                                      NF_CT_DIRECTION(h)))
 648                         goto out;
 649         hlist_nulls_for_each_entry(h, n, &net->ct.hash[reply_hash], hnnode)
 650                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 651                                       &h->tuple) &&
 652                     nf_ct_zone_equal(nf_ct_tuplehash_to_ctrack(h), zone,
 653                                      NF_CT_DIRECTION(h)))
 654                         goto out;
 655
 656         /* Timer relative to confirmation time, not original
 657            setting time, otherwise we'd get timer wrap in
 658            weird delay cases. */
 659         ct->timeout.expires += jiffies;
 660         add_timer(&ct->timeout);
 661         atomic_inc(&ct->ct_general.use);
 662         ct->status |= IPS_CONFIRMED;
 663
 664         /* set conntrack timestamp, if enabled. */
 665         tstamp = nf_conn_tstamp_find(ct);
 666         if (tstamp) {
 667                 if (skb->tstamp.tv64 == 0)
 668                         __net_timestamp(skb);
 669
 670                 tstamp->start = ktime_to_ns(skb->tstamp);
 671         }
 672         /* Since the lookup is lockless, hash insertion must be done after
 673          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 674          * guarantee that no other CPU can find the conntrack before the above
 675          * stores are visible.
 676          */
 677         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 678         nf_conntrack_double_unlock(hash, reply_hash);
 679         NF_CT_STAT_INC(net, insert);
 680         local_bh_enable();
 681
 682         help = nfct_help(ct);
 683         if (help && help->helper)
 684                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 685
 686         nf_conntrack_event_cache(master_ct(ct) ?
 687                                  IPCT_RELATED : IPCT_NEW, ct);
 688         return NF_ACCEPT;
 689
 690 out:
 691         nf_ct_add_to_dying_list(ct);
 692         nf_conntrack_double_unlock(hash, reply_hash);
 693         NF_CT_STAT_INC(net, insert_failed);
 694         local_bh_enable();
 695         return NF_DROP;
 696 }
 697 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 698
 699 /* Returns true if a connection correspondings to the tuple (required
 700    for NAT). */
 701 int
 702 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 703                          const struct nf_conn *ignored_conntrack)
 704 {
 705         struct net *net = nf_ct_net(ignored_conntrack);
 706         const struct nf_conntrack_zone *zone;
 707         struct nf_conntrack_tuple_hash *h;
 708         struct hlist_nulls_node *n;
 709         struct nf_conn *ct;
 710         unsigned int hash;
 711
 712         zone = nf_ct_zone(ignored_conntrack);
 713         hash = hash_conntrack(net, tuple);
 714
 715         /* Disable BHs the entire time since we need to disable them at
 716          * least once for the stats anyway.
 717          */
 718         rcu_read_lock_bh();
 719         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 720                 ct = nf_ct_tuplehash_to_ctrack(h);
 721                 if (ct != ignored_conntrack &&
 722                     nf_ct_tuple_equal(tuple, &h->tuple) &&
 723                     nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h))) {
 724                         NF_CT_STAT_INC(net, found);
 725                         rcu_read_unlock_bh();
 726                         return 1;
 727                 }
 728                 NF_CT_STAT_INC(net, searched);
 729         }
 730         rcu_read_unlock_bh();
 731
 732         return 0;
 733 }
 734 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 735
 736 #define NF_CT_EVICTION_RANGE    8
 737
 738 /* There's a small race here where we may free a just-assured
 739    connection.  Too bad: we're in trouble anyway. */
 740 static noinline int early_drop(struct net *net, unsigned int _hash)
 741 {
 742         /* Use oldest entry, which is roughly LRU */
 743         struct nf_conntrack_tuple_hash *h;
 744         struct nf_conn *ct = NULL, *tmp;
 745         struct hlist_nulls_node *n;
 746         unsigned int i = 0, cnt = 0;
 747         int dropped = 0;
 748         unsigned int hash, sequence;
 749         spinlock_t *lockp;
 750
 751         local_bh_disable();
 752 restart:
 753         sequence = read_seqcount_begin(&net->ct.generation);
 754         hash = hash_bucket(_hash, net);
 755         for (; i < net->ct.htable_size; i++) {
 756                 lockp = &nf_conntrack_locks[hash % CONNTRACK_LOCKS];
 757                 spin_lock(lockp);
 758                 if (read_seqcount_retry(&net->ct.generation, sequence)) {
 759                         spin_unlock(lockp);
 760                         goto restart;
 761                 }
 762                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 763                                          hnnode) {
 764                         tmp = nf_ct_tuplehash_to_ctrack(h);
 765                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status) &&
 766                             !nf_ct_is_dying(tmp) &&
 767                             atomic_inc_not_zero(&tmp->ct_general.use)) {
 768                                 ct = tmp;
 769                                 break;
 770                         }
 771                         cnt++;
 772                 }
 773
 774                 hash = (hash + 1) % net->ct.htable_size;
 775                 spin_unlock(lockp);
 776
 777                 if (ct || cnt >= NF_CT_EVICTION_RANGE)
 778                         break;
 779
 780         }
 781         local_bh_enable();
 782
 783         if (!ct)
 784                 return dropped;
 785
 786         if (del_timer(&ct->timeout)) {
 787                 if (nf_ct_delete(ct, 0, 0)) {
 788                         dropped = 1;
 789                         NF_CT_STAT_INC_ATOMIC(net, early_drop);
 790                 }
 791         }
 792         nf_ct_put(ct);
 793         return dropped;
 794 }
 795
 796 void init_nf_conntrack_hash_rnd(void)
 797 {
 798         unsigned int rand;
 799
 800         /*
 801          * Why not initialize nf_conntrack_rnd in a "init()" function ?
 802          * Because there isn't enough entropy when system initializing,
 803          * and we initialize it as late as possible.
 804          */
 805         do {
 806                 get_random_bytes(&rand, sizeof(rand));
 807         } while (!rand);
 808         cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
 809 }
 810
 811 static struct nf_conn *
 812 __nf_conntrack_alloc(struct net *net,
 813                      const struct nf_conntrack_zone *zone,
 814                      const struct nf_conntrack_tuple *orig,
 815                      const struct nf_conntrack_tuple *repl,
 816                      gfp_t gfp, u32 hash)
 817 {
 818         struct nf_conn *ct;
 819
 820         if (unlikely(!nf_conntrack_hash_rnd)) {
 821                 init_nf_conntrack_hash_rnd();
 822                 /* recompute the hash as nf_conntrack_hash_rnd is initialized */
 823                 hash = hash_conntrack_raw(orig);
 824         }
 825
 826         /* We don't want any race condition at early drop stage */
 827         atomic_inc(&net->ct.count);
 828
 829         if (nf_conntrack_max &&
 830             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
 831                 if (!early_drop(net, hash)) {
 832                         atomic_dec(&net->ct.count);
 833                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
 834                         return ERR_PTR(-ENOMEM);
 835                 }
 836         }
 837
 838         /*
 839          * Do not use kmem_cache_zalloc(), as this cache uses
 840          * SLAB_DESTROY_BY_RCU.
 841          */
 842         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
 843         if (ct == NULL)
 844                 goto out;
 845
 846         spin_lock_init(&ct->lock);
 847         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 848         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
 849         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 850         /* save hash for reusing when confirming */
 851         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
 852         ct->status = 0;
 853         /* Don't set timer yet: wait for confirmation */
 854         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 855         write_pnet(&ct->ct_net, net);
 856         memset(&ct->__nfct_init_offset[0], 0,
 857                offsetof(struct nf_conn, proto) -
 858                offsetof(struct nf_conn, __nfct_init_offset[0]));
 859
 860         if (zone && nf_ct_zone_add(ct, GFP_ATOMIC, zone) < 0)
 861                 goto out_free;
 862
 863         /* Because we use RCU lookups, we set ct_general.use to zero before
 864          * this is inserted in any list.
 865          */
 866         atomic_set(&ct->ct_general.use, 0);
 867         return ct;
 868 out_free:
 869         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 870 out:
 871         atomic_dec(&net->ct.count);
 872         return ERR_PTR(-ENOMEM);
 873 }
 874
 875 struct nf_conn *nf_conntrack_alloc(struct net *net,
 876                                    const struct nf_conntrack_zone *zone,
 877                                    const struct nf_conntrack_tuple *orig,
 878                                    const struct nf_conntrack_tuple *repl,
 879                                    gfp_t gfp)
 880 {
 881         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
 882 }
 883 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 884
 885 void nf_conntrack_free(struct nf_conn *ct)
 886 {
 887         struct net *net = nf_ct_net(ct);
 888
 889         /* A freed object has refcnt == 0, that's
 890          * the golden rule for SLAB_DESTROY_BY_RCU
 891          */
 892         NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 0);
 893
 894         nf_ct_ext_destroy(ct);
 895         nf_ct_ext_free(ct);
 896         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 897         smp_mb__before_atomic();
 898         atomic_dec(&net->ct.count);
 899 }
 900 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 901
 902
 903 /* Allocate a new conntrack: we return -ENOMEM if classification
 904    failed due to stress.  Otherwise it really is unclassifiable. */
 905 static struct nf_conntrack_tuple_hash *
 906 init_conntrack(struct net *net, struct nf_conn *tmpl,
 907                const struct nf_conntrack_tuple *tuple,
 908                struct nf_conntrack_l3proto *l3proto,
 909                struct nf_conntrack_l4proto *l4proto,
 910                struct sk_buff *skb,
 911                unsigned int dataoff, u32 hash)
 912 {
 913         struct nf_conn *ct;
 914         struct nf_conn_help *help;
 915         struct nf_conntrack_tuple repl_tuple;
 916         struct nf_conntrack_ecache *ecache;
 917         struct nf_conntrack_expect *exp = NULL;
 918         const struct nf_conntrack_zone *zone;
 919         struct nf_conn_timeout *timeout_ext;
 920         struct nf_conntrack_zone tmp;
 921         unsigned int *timeouts;
 922
 923         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 924                 pr_debug("Can't invert tuple.\n");
 925                 return NULL;
 926         }
 927
 928         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
 929         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
 930                                   hash);
 931         if (IS_ERR(ct))
 932                 return (struct nf_conntrack_tuple_hash *)ct;
 933
 934         if (tmpl && nfct_synproxy(tmpl)) {
 935                 nfct_seqadj_ext_add(ct);
 936                 nfct_synproxy_ext_add(ct);
 937         }
 938
 939         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
 940         if (timeout_ext)
 941                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 942         else
 943                 timeouts = l4proto->get_timeouts(net);
 944
 945         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
 946                 nf_conntrack_free(ct);
 947                 pr_debug("init conntrack: can't track with proto module\n");
 948                 return NULL;
 949         }
 950
 951         if (timeout_ext)
 952                 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC);
 953
 954         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 955         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 956         nf_ct_labels_ext_add(ct);
 957
 958         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
 959         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
 960                                  ecache ? ecache->expmask : 0,
 961                              GFP_ATOMIC);
 962
 963         local_bh_disable();
 964         if (net->ct.expect_count) {
 965                 spin_lock(&nf_conntrack_expect_lock);
 966                 exp = nf_ct_find_expectation(net, zone, tuple);
 967                 if (exp) {
 968                         pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 969                                  ct, exp);
 970                         /* Welcome, Mr. Bond.  We've been expecting you... */
 971                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
 972                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
 973                         ct->master = exp->master;
 974                         if (exp->helper) {
 975                                 help = nf_ct_helper_ext_add(ct, exp->helper,
 976                                                             GFP_ATOMIC);
 977                                 if (help)
 978                                         rcu_assign_pointer(help->helper, exp->helper);
 979                         }
 980
 981 #ifdef CONFIG_NF_CONNTRACK_MARK
 982                         ct->mark = exp->master->mark;
 983 #endif
 984 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 985                         ct->secmark = exp->master->secmark;
 986 #endif
 987                         NF_CT_STAT_INC(net, expect_new);
 988                 }
 989                 spin_unlock(&nf_conntrack_expect_lock);
 990         }
 991         if (!exp) {
 992                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
 993                 NF_CT_STAT_INC(net, new);
 994         }
 995
 996         /* Now it is inserted into the unconfirmed list, bump refcount */
 997         nf_conntrack_get(&ct->ct_general);
 998         nf_ct_add_to_unconfirmed_list(ct);
 999
1000         local_bh_enable();
1001
1002         if (exp) {
1003                 if (exp->expectfn)
1004                         exp->expectfn(ct, exp);
1005                 nf_ct_expect_put(exp);
1006         }
1007
1008         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1009 }
1010
1011 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
1012 static inline struct nf_conn *
1013 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
1014                   struct sk_buff *skb,
1015                   unsigned int dataoff,
1016                   u_int16_t l3num,
1017                   u_int8_t protonum,
1018                   struct nf_conntrack_l3proto *l3proto,
1019                   struct nf_conntrack_l4proto *l4proto,
1020                   int *set_reply,
1021                   enum ip_conntrack_info *ctinfo)
1022 {
1023         const struct nf_conntrack_zone *zone;
1024         struct nf_conntrack_tuple tuple;
1025         struct nf_conntrack_tuple_hash *h;
1026         struct nf_conntrack_zone tmp;
1027         struct nf_conn *ct;
1028         u32 hash;
1029
1030         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1031                              dataoff, l3num, protonum, &tuple, l3proto,
1032                              l4proto)) {
1033                 pr_debug("resolve_normal_ct: Can't get tuple\n");
1034                 return NULL;
1035         }
1036
1037         /* look for tuple match */
1038         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1039         hash = hash_conntrack_raw(&tuple);
1040         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
1041         if (!h) {
1042                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
1043                                    skb, dataoff, hash);
1044                 if (!h)
1045                         return NULL;
1046                 if (IS_ERR(h))
1047                         return (void *)h;
1048         }
1049         ct = nf_ct_tuplehash_to_ctrack(h);
1050
1051         /* It exists; we have (non-exclusive) reference. */
1052         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1053                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
1054                 /* Please set reply bit if this packet OK */
1055                 *set_reply = 1;
1056         } else {
1057                 /* Once we've had two way comms, always ESTABLISHED. */
1058                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1059                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
1060                         *ctinfo = IP_CT_ESTABLISHED;
1061                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1062                         pr_debug("nf_conntrack_in: related packet for %p\n",
1063                                  ct);
1064                         *ctinfo = IP_CT_RELATED;
1065                 } else {
1066                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
1067                         *ctinfo = IP_CT_NEW;
1068                 }
1069                 *set_reply = 0;
1070         }
1071         skb->nfct = &ct->ct_general;
1072         skb->nfctinfo = *ctinfo;
1073         return ct;
1074 }
1075
1076 unsigned int
1077 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
1078                 struct sk_buff *skb)
1079 {
1080         struct nf_conn *ct, *tmpl = NULL;
1081         enum ip_conntrack_info ctinfo;
1082         struct nf_conntrack_l3proto *l3proto;
1083         struct nf_conntrack_l4proto *l4proto;
1084         unsigned int *timeouts;
1085         unsigned int dataoff;
1086         u_int8_t protonum;
1087         int set_reply = 0;
1088         int ret;
1089
1090         if (skb->nfct) {
1091                 /* Previously seen (loopback or untracked)?  Ignore. */
1092                 tmpl = (struct nf_conn *)skb->nfct;
1093                 if (!nf_ct_is_template(tmpl)) {
1094                         NF_CT_STAT_INC_ATOMIC(net, ignore);
1095                         return NF_ACCEPT;
1096                 }
1097                 skb->nfct = NULL;
1098         }
1099
1100         /* rcu_read_lock()ed by nf_hook_slow */
1101         l3proto = __nf_ct_l3proto_find(pf);
1102         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
1103                                    &dataoff, &protonum);
1104         if (ret <= 0) {
1105                 pr_debug("not prepared to track yet or error occurred\n");
1106                 NF_CT_STAT_INC_ATOMIC(net, error);
1107                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1108                 ret = -ret;
1109                 goto out;
1110         }
1111
1112         l4proto = __nf_ct_l4proto_find(pf, protonum);
1113
1114         /* It may be an special packet, error, unclean...
1115          * inverse of the return code tells to the netfilter
1116          * core what to do with the packet. */
1117         if (l4proto->error != NULL) {
1118                 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
1119                                      pf, hooknum);
1120                 if (ret <= 0) {
1121                         NF_CT_STAT_INC_ATOMIC(net, error);
1122                         NF_CT_STAT_INC_ATOMIC(net, invalid);
1123                         ret = -ret;
1124                         goto out;
1125                 }
1126                 /* ICMP[v6] protocol trackers may assign one conntrack. */
1127                 if (skb->nfct)
1128                         goto out;
1129         }
1130
1131         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
1132                                l3proto, l4proto, &set_reply, &ctinfo);
1133         if (!ct) {
1134                 /* Not valid part of a connection */
1135                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1136                 ret = NF_ACCEPT;
1137                 goto out;
1138         }
1139
1140         if (IS_ERR(ct)) {
1141                 /* Too stressed to deal. */
1142                 NF_CT_STAT_INC_ATOMIC(net, drop);
1143                 ret = NF_DROP;
1144                 goto out;
1145         }
1146
1147         NF_CT_ASSERT(skb->nfct);
1148
1149         /* Decide what timeout policy we want to apply to this flow. */
1150         timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1151
1152         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1153         if (ret <= 0) {
1154                 /* Invalid: inverse of the return code tells
1155                  * the netfilter core what to do */
1156                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1157                 nf_conntrack_put(skb->nfct);
1158                 skb->nfct = NULL;
1159                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1160                 if (ret == -NF_DROP)
1161                         NF_CT_STAT_INC_ATOMIC(net, drop);
1162                 ret = -ret;
1163                 goto out;
1164         }
1165
1166         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1167                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1168 out:
1169         if (tmpl) {
1170                 /* Special case: we have to repeat this hook, assign the
1171                  * template again to this packet. We assume that this packet
1172                  * has no conntrack assigned. This is used by nf_ct_tcp. */
1173                 if (ret == NF_REPEAT)
1174                         skb->nfct = (struct nf_conntrack *)tmpl;
1175                 else
1176                         nf_ct_put(tmpl);
1177         }
1178
1179         return ret;
1180 }
1181 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1182
1183 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1184                           const struct nf_conntrack_tuple *orig)
1185 {
1186         bool ret;
1187
1188         rcu_read_lock();
1189         ret = nf_ct_invert_tuple(inverse, orig,
1190                                  __nf_ct_l3proto_find(orig->src.l3num),
1191                                  __nf_ct_l4proto_find(orig->src.l3num,
1192                                                       orig->dst.protonum));
1193         rcu_read_unlock();
1194         return ret;
1195 }
1196 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1197
1198 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1199    implicitly racy: see __nf_conntrack_confirm */
1200 void nf_conntrack_alter_reply(struct nf_conn *ct,
1201                               const struct nf_conntrack_tuple *newreply)
1202 {
1203         struct nf_conn_help *help = nfct_help(ct);
1204
1205         /* Should be unconfirmed, so not in hash table yet */
1206         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1207
1208         pr_debug("Altering reply tuple of %p to ", ct);
1209         nf_ct_dump_tuple(newreply);
1210
1211         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1212         if (ct->master || (help && !hlist_empty(&help->expectations)))
1213                 return;
1214
1215         rcu_read_lock();
1216         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1217         rcu_read_unlock();
1218 }
1219 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1220
1221 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1222 void __nf_ct_refresh_acct(struct nf_conn *ct,
1223                           enum ip_conntrack_info ctinfo,
1224                           const struct sk_buff *skb,
1225                           unsigned long extra_jiffies,
1226                           int do_acct)
1227 {
1228         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1229         NF_CT_ASSERT(skb);
1230
1231         /* Only update if this is not a fixed timeout */
1232         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1233                 goto acct;
1234
1235         /* If not in hash table, timer will not be active yet */
1236         if (!nf_ct_is_confirmed(ct)) {
1237                 ct->timeout.expires = extra_jiffies;
1238         } else {
1239                 unsigned long newtime = jiffies + extra_jiffies;
1240
1241                 /* Only update the timeout if the new timeout is at least
1242                    HZ jiffies from the old timeout. Need del_timer for race
1243                    avoidance (may already be dying). */
1244                 if (newtime - ct->timeout.expires >= HZ)
1245                         mod_timer_pending(&ct->timeout, newtime);
1246         }
1247
1248 acct:
1249         if (do_acct) {
1250                 struct nf_conn_acct *acct;
1251
1252                 acct = nf_conn_acct_find(ct);
1253                 if (acct) {
1254                         struct nf_conn_counter *counter = acct->counter;
1255
1256                         atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
1257                         atomic64_add(skb->len, &counter[CTINFO2DIR(ctinfo)].bytes);
1258                 }
1259         }
1260 }
1261 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1262
1263 bool __nf_ct_kill_acct(struct nf_conn *ct,
1264                        enum ip_conntrack_info ctinfo,
1265                        const struct sk_buff *skb,
1266                        int do_acct)
1267 {
1268         if (do_acct) {
1269                 struct nf_conn_acct *acct;
1270
1271                 acct = nf_conn_acct_find(ct);
1272                 if (acct) {
1273                         struct nf_conn_counter *counter = acct->counter;
1274
1275                         atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
1276                         atomic64_add(skb->len - skb_network_offset(skb),
1277                                      &counter[CTINFO2DIR(ctinfo)].bytes);
1278                 }
1279         }
1280
1281         if (del_timer(&ct->timeout)) {
1282                 ct->timeout.function((unsigned long)ct);
1283                 return true;
1284         }
1285         return false;
1286 }
1287 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1288
1289 #ifdef CONFIG_NF_CONNTRACK_ZONES
1290 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1291         .len    = sizeof(struct nf_conntrack_zone),
1292         .align  = __alignof__(struct nf_conntrack_zone),
1293         .id     = NF_CT_EXT_ZONE,
1294 };
1295 #endif
1296
1297 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1298
1299 #include <linux/netfilter/nfnetlink.h>
1300 #include <linux/netfilter/nfnetlink_conntrack.h>
1301 #include <linux/mutex.h>
1302
1303 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1304  * in ip_conntrack_core, since we don't want the protocols to autoload
1305  * or depend on ctnetlink */
1306 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1307                                const struct nf_conntrack_tuple *tuple)
1308 {
1309         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1310             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1311                 goto nla_put_failure;
1312         return 0;
1313
1314 nla_put_failure:
1315         return -1;
1316 }
1317 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1318
1319 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1320         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1321         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1322 };
1323 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1324
1325 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1326                                struct nf_conntrack_tuple *t)
1327 {
1328         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1329                 return -EINVAL;
1330
1331         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1332         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1333
1334         return 0;
1335 }
1336 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1337
1338 int nf_ct_port_nlattr_tuple_size(void)
1339 {
1340         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1341 }
1342 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1343 #endif
1344
1345 /* Used by ipt_REJECT and ip6t_REJECT. */
1346 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1347 {
1348         struct nf_conn *ct;
1349         enum ip_conntrack_info ctinfo;
1350
1351         /* This ICMP is in reverse direction to the packet which caused it */
1352         ct = nf_ct_get(skb, &ctinfo);
1353         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1354                 ctinfo = IP_CT_RELATED_REPLY;
1355         else
1356                 ctinfo = IP_CT_RELATED;
1357
1358         /* Attach to new skbuff, and increment count */
1359         nskb->nfct = &ct->ct_general;
1360         nskb->nfctinfo = ctinfo;
1361         nf_conntrack_get(nskb->nfct);
1362 }
1363
1364 /* Bring out ya dead! */
1365 static struct nf_conn *
1366 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1367                 void *data, unsigned int *bucket)
1368 {
1369         struct nf_conntrack_tuple_hash *h;
1370         struct nf_conn *ct;
1371         struct hlist_nulls_node *n;
1372         int cpu;
1373         spinlock_t *lockp;
1374
1375         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1376                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
1377                 local_bh_disable();
1378                 spin_lock(lockp);
1379                 if (*bucket < net->ct.htable_size) {
1380                         hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1381                                 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
1382                                         continue;
1383                                 ct = nf_ct_tuplehash_to_ctrack(h);
1384                                 if (iter(ct, data))
1385                                         goto found;
1386                         }
1387                 }
1388                 spin_unlock(lockp);
1389                 local_bh_enable();
1390         }
1391
1392         for_each_possible_cpu(cpu) {
1393                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1394
1395                 spin_lock_bh(&pcpu->lock);
1396                 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
1397                         ct = nf_ct_tuplehash_to_ctrack(h);
1398                         if (iter(ct, data))
1399                                 set_bit(IPS_DYING_BIT, &ct->status);
1400                 }
1401                 spin_unlock_bh(&pcpu->lock);
1402         }
1403         return NULL;
1404 found:
1405         atomic_inc(&ct->ct_general.use);
1406         spin_unlock(lockp);
1407         local_bh_enable();
1408         return ct;
1409 }
1410
1411 void nf_ct_iterate_cleanup(struct net *net,
1412                            int (*iter)(struct nf_conn *i, void *data),
1413                            void *data, u32 portid, int report)
1414 {
1415         struct nf_conn *ct;
1416         unsigned int bucket = 0;
1417
1418         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1419                 /* Time to push up daises... */
1420                 if (del_timer(&ct->timeout))
1421                         nf_ct_delete(ct, portid, report);
1422
1423                 /* ... else the timer will get him soon. */
1424
1425                 nf_ct_put(ct);
1426         }
1427 }
1428 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1429
1430 static int kill_all(struct nf_conn *i, void *data)
1431 {
1432         return 1;
1433 }
1434
1435 void nf_ct_free_hashtable(void *hash, unsigned int size)
1436 {
1437         if (is_vmalloc_addr(hash))
1438                 vfree(hash);
1439         else
1440                 free_pages((unsigned long)hash,
1441                            get_order(sizeof(struct hlist_head) * size));
1442 }
1443 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1444
1445 static int untrack_refs(void)
1446 {
1447         int cnt = 0, cpu;
1448
1449         for_each_possible_cpu(cpu) {
1450                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1451
1452                 cnt += atomic_read(&ct->ct_general.use) - 1;
1453         }
1454         return cnt;
1455 }
1456
1457 void nf_conntrack_cleanup_start(void)
1458 {
1459         RCU_INIT_POINTER(ip_ct_attach, NULL);
1460 }
1461
1462 void nf_conntrack_cleanup_end(void)
1463 {
1464         RCU_INIT_POINTER(nf_ct_destroy, NULL);
1465         while (untrack_refs() > 0)
1466                 schedule();
1467
1468 #ifdef CONFIG_NF_CONNTRACK_ZONES
1469         nf_ct_extend_unregister(&nf_ct_zone_extend);
1470 #endif
1471         nf_conntrack_proto_fini();
1472         nf_conntrack_seqadj_fini();
1473         nf_conntrack_labels_fini();
1474         nf_conntrack_helper_fini();
1475         nf_conntrack_timeout_fini();
1476         nf_conntrack_ecache_fini();
1477         nf_conntrack_tstamp_fini();
1478         nf_conntrack_acct_fini();
1479         nf_conntrack_expect_fini();
1480 }
1481
1482 /*
1483  * Mishearing the voices in his head, our hero wonders how he's
1484  * supposed to kill the mall.
1485  */
1486 void nf_conntrack_cleanup_net(struct net *net)
1487 {
1488         LIST_HEAD(single);
1489
1490         list_add(&net->exit_list, &single);
1491         nf_conntrack_cleanup_net_list(&single);
1492 }
1493
1494 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
1495 {
1496         int busy;
1497         struct net *net;
1498
1499         /*
1500          * This makes sure all current packets have passed through
1501          *  netfilter framework.  Roll on, two-stage module
1502          *  delete...
1503          */
1504         synchronize_net();
1505 i_see_dead_people:
1506         busy = 0;
1507         list_for_each_entry(net, net_exit_list, exit_list) {
1508                 nf_ct_iterate_cleanup(net, kill_all, NULL, 0, 0);
1509                 if (atomic_read(&net->ct.count) != 0)
1510                         busy = 1;
1511         }
1512         if (busy) {
1513                 schedule();
1514                 goto i_see_dead_people;
1515         }
1516
1517         list_for_each_entry(net, net_exit_list, exit_list) {
1518                 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1519                 nf_conntrack_proto_pernet_fini(net);
1520                 nf_conntrack_helper_pernet_fini(net);
1521                 nf_conntrack_ecache_pernet_fini(net);
1522                 nf_conntrack_tstamp_pernet_fini(net);
1523                 nf_conntrack_acct_pernet_fini(net);
1524                 nf_conntrack_expect_pernet_fini(net);
1525                 kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1526                 kfree(net->ct.slabname);
1527                 free_percpu(net->ct.stat);
1528                 free_percpu(net->ct.pcpu_lists);
1529         }
1530 }
1531
1532 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1533 {
1534         struct hlist_nulls_head *hash;
1535         unsigned int nr_slots, i;
1536         size_t sz;
1537
1538         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1539         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1540         sz = nr_slots * sizeof(struct hlist_nulls_head);
1541         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1542                                         get_order(sz));
1543         if (!hash)
1544                 hash = vzalloc(sz);
1545
1546         if (hash && nulls)
1547                 for (i = 0; i < nr_slots; i++)
1548                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1549
1550         return hash;
1551 }
1552 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1553
1554 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1555 {
1556         int i, bucket, rc;
1557         unsigned int hashsize, old_size;
1558         struct hlist_nulls_head *hash, *old_hash;
1559         struct nf_conntrack_tuple_hash *h;
1560         struct nf_conn *ct;
1561
1562         if (current->nsproxy->net_ns != &init_net)
1563                 return -EOPNOTSUPP;
1564
1565         /* On boot, we can set this without any fancy locking. */
1566         if (!nf_conntrack_htable_size)
1567                 return param_set_uint(val, kp);
1568
1569         rc = kstrtouint(val, 0, &hashsize);
1570         if (rc)
1571                 return rc;
1572         if (!hashsize)
1573                 return -EINVAL;
1574
1575         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1576         if (!hash)
1577                 return -ENOMEM;
1578
1579         local_bh_disable();
1580         nf_conntrack_all_lock();
1581         write_seqcount_begin(&init_net.ct.generation);
1582
1583         /* Lookups in the old hash might happen in parallel, which means we
1584          * might get false negatives during connection lookup. New connections
1585          * created because of a false negative won't make it into the hash
1586          * though since that required taking the locks.
1587          */
1588
1589         for (i = 0; i < init_net.ct.htable_size; i++) {
1590                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1591                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1592                                         struct nf_conntrack_tuple_hash, hnnode);
1593                         ct = nf_ct_tuplehash_to_ctrack(h);
1594                         hlist_nulls_del_rcu(&h->hnnode);
1595                         bucket = __hash_conntrack(&h->tuple, hashsize);
1596                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1597                 }
1598         }
1599         old_size = init_net.ct.htable_size;
1600         old_hash = init_net.ct.hash;
1601
1602         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1603         init_net.ct.hash = hash;
1604
1605         write_seqcount_end(&init_net.ct.generation);
1606         nf_conntrack_all_unlock();
1607         local_bh_enable();
1608
1609         nf_ct_free_hashtable(old_hash, old_size);
1610         return 0;
1611 }
1612 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1613
1614 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1615                   &nf_conntrack_htable_size, 0600);
1616
1617 void nf_ct_untracked_status_or(unsigned long bits)
1618 {
1619         int cpu;
1620
1621         for_each_possible_cpu(cpu)
1622                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1623 }
1624 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1625
1626 int nf_conntrack_init_start(void)
1627 {
1628         int max_factor = 8;
1629         int i, ret, cpu;
1630
1631         for (i = 0; i < CONNTRACK_LOCKS; i++)
1632                 spin_lock_init(&nf_conntrack_locks[i]);
1633
1634         if (!nf_conntrack_htable_size) {
1635                 /* Idea from tcp.c: use 1/16384 of memory.
1636                  * On i386: 32MB machine has 512 buckets.
1637                  * >= 1GB machines have 16384 buckets.
1638                  * >= 4GB machines have 65536 buckets.
1639                  */
1640                 nf_conntrack_htable_size
1641                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1642                            / sizeof(struct hlist_head));
1643                 if (totalram_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
1644                         nf_conntrack_htable_size = 65536;
1645                 else if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1646                         nf_conntrack_htable_size = 16384;
1647                 if (nf_conntrack_htable_size < 32)
1648                         nf_conntrack_htable_size = 32;
1649
1650                 /* Use a max. factor of four by default to get the same max as
1651                  * with the old struct list_heads. When a table size is given
1652                  * we use the old value of 8 to avoid reducing the max.
1653                  * entries. */
1654                 max_factor = 4;
1655         }
1656         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1657
1658         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1659                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1660                nf_conntrack_max);
1661
1662         ret = nf_conntrack_expect_init();
1663         if (ret < 0)
1664                 goto err_expect;
1665
1666         ret = nf_conntrack_acct_init();
1667         if (ret < 0)
1668                 goto err_acct;
1669
1670         ret = nf_conntrack_tstamp_init();
1671         if (ret < 0)
1672                 goto err_tstamp;
1673
1674         ret = nf_conntrack_ecache_init();
1675         if (ret < 0)
1676                 goto err_ecache;
1677
1678         ret = nf_conntrack_timeout_init();
1679         if (ret < 0)
1680                 goto err_timeout;
1681
1682         ret = nf_conntrack_helper_init();
1683         if (ret < 0)
1684                 goto err_helper;
1685
1686         ret = nf_conntrack_labels_init();
1687         if (ret < 0)
1688                 goto err_labels;
1689
1690         ret = nf_conntrack_seqadj_init();
1691         if (ret < 0)
1692                 goto err_seqadj;
1693
1694 #ifdef CONFIG_NF_CONNTRACK_ZONES
1695         ret = nf_ct_extend_register(&nf_ct_zone_extend);
1696         if (ret < 0)
1697                 goto err_extend;
1698 #endif
1699         ret = nf_conntrack_proto_init();
1700         if (ret < 0)
1701                 goto err_proto;
1702
1703         /* Set up fake conntrack: to never be deleted, not in any hashes */
1704         for_each_possible_cpu(cpu) {
1705                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1706                 write_pnet(&ct->ct_net, &init_net);
1707                 atomic_set(&ct->ct_general.use, 1);
1708         }
1709         /*  - and look it like as a confirmed connection */
1710         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1711         return 0;
1712
1713 err_proto:
1714 #ifdef CONFIG_NF_CONNTRACK_ZONES
1715         nf_ct_extend_unregister(&nf_ct_zone_extend);
1716 err_extend:
1717 #endif
1718         nf_conntrack_seqadj_fini();
1719 err_seqadj:
1720         nf_conntrack_labels_fini();
1721 err_labels:
1722         nf_conntrack_helper_fini();
1723 err_helper:
1724         nf_conntrack_timeout_fini();
1725 err_timeout:
1726         nf_conntrack_ecache_fini();
1727 err_ecache:
1728         nf_conntrack_tstamp_fini();
1729 err_tstamp:
1730         nf_conntrack_acct_fini();
1731 err_acct:
1732         nf_conntrack_expect_fini();
1733 err_expect:
1734         return ret;
1735 }
1736
1737 void nf_conntrack_init_end(void)
1738 {
1739         /* For use by REJECT target */
1740         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1741         RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1742 }
1743
1744 /*
1745  * We need to use special "null" values, not used in hash table
1746  */
1747 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1748 #define DYING_NULLS_VAL         ((1<<30)+1)
1749 #define TEMPLATE_NULLS_VAL      ((1<<30)+2)
1750
1751 int nf_conntrack_init_net(struct net *net)
1752 {
1753         int ret = -ENOMEM;
1754         int cpu;
1755
1756         atomic_set(&net->ct.count, 0);
1757         seqcount_init(&net->ct.generation);
1758
1759         net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
1760         if (!net->ct.pcpu_lists)
1761                 goto err_stat;
1762
1763         for_each_possible_cpu(cpu) {
1764                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1765
1766                 spin_lock_init(&pcpu->lock);
1767                 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
1768                 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
1769         }
1770
1771         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1772         if (!net->ct.stat)
1773                 goto err_pcpu_lists;
1774
1775         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1776         if (!net->ct.slabname)
1777                 goto err_slabname;
1778
1779         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1780                                                         sizeof(struct nf_conn), 0,
1781                                                         SLAB_DESTROY_BY_RCU, NULL);
1782         if (!net->ct.nf_conntrack_cachep) {
1783                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1784                 goto err_cache;
1785         }
1786
1787         net->ct.htable_size = nf_conntrack_htable_size;
1788         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1789         if (!net->ct.hash) {
1790                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1791                 goto err_hash;
1792         }
1793         ret = nf_conntrack_expect_pernet_init(net);
1794         if (ret < 0)
1795                 goto err_expect;
1796         ret = nf_conntrack_acct_pernet_init(net);
1797         if (ret < 0)
1798                 goto err_acct;
1799         ret = nf_conntrack_tstamp_pernet_init(net);
1800         if (ret < 0)
1801                 goto err_tstamp;
1802         ret = nf_conntrack_ecache_pernet_init(net);
1803         if (ret < 0)
1804                 goto err_ecache;
1805         ret = nf_conntrack_helper_pernet_init(net);
1806         if (ret < 0)
1807                 goto err_helper;
1808         ret = nf_conntrack_proto_pernet_init(net);
1809         if (ret < 0)
1810                 goto err_proto;
1811         return 0;
1812
1813 err_proto:
1814         nf_conntrack_helper_pernet_fini(net);
1815 err_helper:
1816         nf_conntrack_ecache_pernet_fini(net);
1817 err_ecache:
1818         nf_conntrack_tstamp_pernet_fini(net);
1819 err_tstamp:
1820         nf_conntrack_acct_pernet_fini(net);
1821 err_acct:
1822         nf_conntrack_expect_pernet_fini(net);
1823 err_expect:
1824         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1825 err_hash:
1826         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1827 err_cache:
1828         kfree(net->ct.slabname);
1829 err_slabname:
1830         free_percpu(net->ct.stat);
1831 err_pcpu_lists:
1832         free_percpu(net->ct.pcpu_lists);
1833 err_stat:
1834         return ret;
1835 }