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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/types.h>
  18 #include <linux/netfilter.h>
  19 #include <linux/module.h>
  20 #include <linux/sched.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/stddef.h>
  25 #include <linux/slab.h>
  26 #include <linux/random.h>
  27 #include <linux/jhash.h>
  28 #include <linux/err.h>
  29 #include <linux/percpu.h>
  30 #include <linux/moduleparam.h>
  31 #include <linux/notifier.h>
  32 #include <linux/kernel.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/socket.h>
  35 #include <linux/mm.h>
  36 #include <linux/nsproxy.h>
  37 #include <linux/rculist_nulls.h>
  38
  39 #include <net/netfilter/nf_conntrack.h>
  40 #include <net/netfilter/nf_conntrack_l3proto.h>
  41 #include <net/netfilter/nf_conntrack_l4proto.h>
  42 #include <net/netfilter/nf_conntrack_expect.h>
  43 #include <net/netfilter/nf_conntrack_helper.h>
  44 #include <net/netfilter/nf_conntrack_seqadj.h>
  45 #include <net/netfilter/nf_conntrack_core.h>
  46 #include <net/netfilter/nf_conntrack_extend.h>
  47 #include <net/netfilter/nf_conntrack_acct.h>
  48 #include <net/netfilter/nf_conntrack_ecache.h>
  49 #include <net/netfilter/nf_conntrack_zones.h>
  50 #include <net/netfilter/nf_conntrack_timestamp.h>
  51 #include <net/netfilter/nf_conntrack_timeout.h>
  52 #include <net/netfilter/nf_conntrack_labels.h>
  53 #include <net/netfilter/nf_conntrack_synproxy.h>
  54 #include <net/netfilter/nf_nat.h>
  55 #include <net/netfilter/nf_nat_core.h>
  56 #include <net/netfilter/nf_nat_helper.h>
  57 #include <net/netns/hash.h>
  58
  59 #define NF_CONNTRACK_VERSION    "0.5.0"
  60
  61 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
  62                                       enum nf_nat_manip_type manip,
  63                                       const struct nlattr *attr) __read_mostly;
  64 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
  65
  66 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
  67 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
  68
  69 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
  70 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
  71
  72 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
  73 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  74
  75 struct conntrack_gc_work {
  76         struct delayed_work     dwork;
  77         u32                     last_bucket;
  78         bool                    exiting;
  79         long                    next_gc_run;
  80 };
  81
  82 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
  83 static __read_mostly spinlock_t nf_conntrack_locks_all_lock;
  84 static __read_mostly DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
  85 static __read_mostly bool nf_conntrack_locks_all;
  86
  87 /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */
  88 #define GC_MAX_BUCKETS_DIV      128u
  89 /* upper bound of full table scan */
  90 #define GC_MAX_SCAN_JIFFIES     (16u * HZ)
  91 /* desired ratio of entries found to be expired */
  92 #define GC_EVICT_RATIO  50u
  93
  94 static struct conntrack_gc_work conntrack_gc_work;
  95
  96 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
  97 {
  98         spin_lock(lock);
  99         while (unlikely(nf_conntrack_locks_all)) {
 100                 spin_unlock(lock);
 101
 102                 /*
 103                  * Order the 'nf_conntrack_locks_all' load vs. the
 104                  * spin_unlock_wait() loads below, to ensure
 105                  * that 'nf_conntrack_locks_all_lock' is indeed held:
 106                  */
 107                 smp_rmb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
 108                 spin_unlock_wait(&nf_conntrack_locks_all_lock);
 109                 spin_lock(lock);
 110         }
 111 }
 112 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
 113
 114 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
 115 {
 116         h1 %= CONNTRACK_LOCKS;
 117         h2 %= CONNTRACK_LOCKS;
 118         spin_unlock(&nf_conntrack_locks[h1]);
 119         if (h1 != h2)
 120                 spin_unlock(&nf_conntrack_locks[h2]);
 121 }
 122
 123 /* return true if we need to recompute hashes (in case hash table was resized) */
 124 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
 125                                      unsigned int h2, unsigned int sequence)
 126 {
 127         h1 %= CONNTRACK_LOCKS;
 128         h2 %= CONNTRACK_LOCKS;
 129         if (h1 <= h2) {
 130                 nf_conntrack_lock(&nf_conntrack_locks[h1]);
 131                 if (h1 != h2)
 132                         spin_lock_nested(&nf_conntrack_locks[h2],
 133                                          SINGLE_DEPTH_NESTING);
 134         } else {
 135                 nf_conntrack_lock(&nf_conntrack_locks[h2]);
 136                 spin_lock_nested(&nf_conntrack_locks[h1],
 137                                  SINGLE_DEPTH_NESTING);
 138         }
 139         if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
 140                 nf_conntrack_double_unlock(h1, h2);
 141                 return true;
 142         }
 143         return false;
 144 }
 145
 146 static void nf_conntrack_all_lock(void)
 147 {
 148         int i;
 149
 150         spin_lock(&nf_conntrack_locks_all_lock);
 151         nf_conntrack_locks_all = true;
 152
 153         /*
 154          * Order the above store of 'nf_conntrack_locks_all' against
 155          * the spin_unlock_wait() loads below, such that if
 156          * nf_conntrack_lock() observes 'nf_conntrack_locks_all'
 157          * we must observe nf_conntrack_locks[] held:
 158          */
 159         smp_mb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
 160
 161         for (i = 0; i < CONNTRACK_LOCKS; i++) {
 162                 spin_unlock_wait(&nf_conntrack_locks[i]);
 163         }
 164 }
 165
 166 static void nf_conntrack_all_unlock(void)
 167 {
 168         /*
 169          * All prior stores must be complete before we clear
 170          * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
 171          * might observe the false value but not the entire
 172          * critical section:
 173          */
 174         smp_store_release(&nf_conntrack_locks_all, false);
 175         spin_unlock(&nf_conntrack_locks_all_lock);
 176 }
 177
 178 unsigned int nf_conntrack_htable_size __read_mostly;
 179 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
 180
 181 unsigned int nf_conntrack_max __read_mostly;
 182 seqcount_t nf_conntrack_generation __read_mostly;
 183
 184 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
 185 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
 186
 187 static unsigned int nf_conntrack_hash_rnd __read_mostly;
 188
 189 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
 190                               const struct net *net)
 191 {
 192         unsigned int n;
 193         u32 seed;
 194
 195         get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
 196
 197         /* The direction must be ignored, so we hash everything up to the
 198          * destination ports (which is a multiple of 4) and treat the last
 199          * three bytes manually.
 200          */
 201         seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
 202         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
 203         return jhash2((u32 *)tuple, n, seed ^
 204                       (((__force __u16)tuple->dst.u.all << 16) |
 205                       tuple->dst.protonum));
 206 }
 207
 208 static u32 scale_hash(u32 hash)
 209 {
 210         return reciprocal_scale(hash, nf_conntrack_htable_size);
 211 }
 212
 213 static u32 __hash_conntrack(const struct net *net,
 214                             const struct nf_conntrack_tuple *tuple,
 215                             unsigned int size)
 216 {
 217         return reciprocal_scale(hash_conntrack_raw(tuple, net), size);
 218 }
 219
 220 static u32 hash_conntrack(const struct net *net,
 221                           const struct nf_conntrack_tuple *tuple)
 222 {
 223         return scale_hash(hash_conntrack_raw(tuple, net));
 224 }
 225
 226 bool
 227 nf_ct_get_tuple(const struct sk_buff *skb,
 228                 unsigned int nhoff,
 229                 unsigned int dataoff,
 230                 u_int16_t l3num,
 231                 u_int8_t protonum,
 232                 struct net *net,
 233                 struct nf_conntrack_tuple *tuple,
 234                 const struct nf_conntrack_l3proto *l3proto,
 235                 const struct nf_conntrack_l4proto *l4proto)
 236 {
 237         memset(tuple, 0, sizeof(*tuple));
 238
 239         tuple->src.l3num = l3num;
 240         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 241                 return false;
 242
 243         tuple->dst.protonum = protonum;
 244         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 245
 246         return l4proto->pkt_to_tuple(skb, dataoff, net, tuple);
 247 }
 248 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 249
 250 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 251                        u_int16_t l3num,
 252                        struct net *net, struct nf_conntrack_tuple *tuple)
 253 {
 254         struct nf_conntrack_l3proto *l3proto;
 255         struct nf_conntrack_l4proto *l4proto;
 256         unsigned int protoff;
 257         u_int8_t protonum;
 258         int ret;
 259
 260         rcu_read_lock();
 261
 262         l3proto = __nf_ct_l3proto_find(l3num);
 263         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 264         if (ret != NF_ACCEPT) {
 265                 rcu_read_unlock();
 266                 return false;
 267         }
 268
 269         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 270
 271         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple,
 272                               l3proto, l4proto);
 273
 274         rcu_read_unlock();
 275         return ret;
 276 }
 277 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 278
 279 bool
 280 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 281                    const struct nf_conntrack_tuple *orig,
 282                    const struct nf_conntrack_l3proto *l3proto,
 283                    const struct nf_conntrack_l4proto *l4proto)
 284 {
 285         memset(inverse, 0, sizeof(*inverse));
 286
 287         inverse->src.l3num = orig->src.l3num;
 288         if (l3proto->invert_tuple(inverse, orig) == 0)
 289                 return false;
 290
 291         inverse->dst.dir = !orig->dst.dir;
 292
 293         inverse->dst.protonum = orig->dst.protonum;
 294         return l4proto->invert_tuple(inverse, orig);
 295 }
 296 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 297
 298 static void
 299 clean_from_lists(struct nf_conn *ct)
 300 {
 301         pr_debug("clean_from_lists(%p)\n", ct);
 302         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 303         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 304
 305         /* Destroy all pending expectations */
 306         nf_ct_remove_expectations(ct);
 307 }
 308
 309 /* must be called with local_bh_disable */
 310 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
 311 {
 312         struct ct_pcpu *pcpu;
 313
 314         /* add this conntrack to the (per cpu) dying list */
 315         ct->cpu = smp_processor_id();
 316         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 317
 318         spin_lock(&pcpu->lock);
 319         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 320                              &pcpu->dying);
 321         spin_unlock(&pcpu->lock);
 322 }
 323
 324 /* must be called with local_bh_disable */
 325 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
 326 {
 327         struct ct_pcpu *pcpu;
 328
 329         /* add this conntrack to the (per cpu) unconfirmed list */
 330         ct->cpu = smp_processor_id();
 331         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 332
 333         spin_lock(&pcpu->lock);
 334         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 335                              &pcpu->unconfirmed);
 336         spin_unlock(&pcpu->lock);
 337 }
 338
 339 /* must be called with local_bh_disable */
 340 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
 341 {
 342         struct ct_pcpu *pcpu;
 343
 344         /* We overload first tuple to link into unconfirmed or dying list.*/
 345         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 346
 347         spin_lock(&pcpu->lock);
 348         BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 349         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 350         spin_unlock(&pcpu->lock);
 351 }
 352
 353 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
 354
 355 /* Released via destroy_conntrack() */
 356 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 357                                  const struct nf_conntrack_zone *zone,
 358                                  gfp_t flags)
 359 {
 360         struct nf_conn *tmpl, *p;
 361
 362         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
 363                 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
 364                 if (!tmpl)
 365                         return NULL;
 366
 367                 p = tmpl;
 368                 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 369                 if (tmpl != p) {
 370                         tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 371                         tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
 372                 }
 373         } else {
 374                 tmpl = kzalloc(sizeof(*tmpl), flags);
 375                 if (!tmpl)
 376                         return NULL;
 377         }
 378
 379         tmpl->status = IPS_TEMPLATE;
 380         write_pnet(&tmpl->ct_net, net);
 381         nf_ct_zone_add(tmpl, zone);
 382         atomic_set(&tmpl->ct_general.use, 0);
 383
 384         return tmpl;
 385 }
 386 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
 387
 388 void nf_ct_tmpl_free(struct nf_conn *tmpl)
 389 {
 390         nf_ct_ext_destroy(tmpl);
 391         nf_ct_ext_free(tmpl);
 392
 393         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
 394                 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
 395         else
 396                 kfree(tmpl);
 397 }
 398 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
 399
 400 static void
 401 destroy_conntrack(struct nf_conntrack *nfct)
 402 {
 403         struct nf_conn *ct = (struct nf_conn *)nfct;
 404         struct nf_conntrack_l4proto *l4proto;
 405
 406         pr_debug("destroy_conntrack(%p)\n", ct);
 407         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 408
 409         if (unlikely(nf_ct_is_template(ct))) {
 410                 nf_ct_tmpl_free(ct);
 411                 return;
 412         }
 413         rcu_read_lock();
 414         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 415         if (l4proto->destroy)
 416                 l4proto->destroy(ct);
 417
 418         rcu_read_unlock();
 419
 420         local_bh_disable();
 421         /* Expectations will have been removed in clean_from_lists,
 422          * except TFTP can create an expectation on the first packet,
 423          * before connection is in the list, so we need to clean here,
 424          * too.
 425          */
 426         nf_ct_remove_expectations(ct);
 427
 428         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 429
 430         local_bh_enable();
 431
 432         if (ct->master)
 433                 nf_ct_put(ct->master);
 434
 435         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 436         nf_conntrack_free(ct);
 437 }
 438
 439 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 440 {
 441         struct net *net = nf_ct_net(ct);
 442         unsigned int hash, reply_hash;
 443         unsigned int sequence;
 444
 445         nf_ct_helper_destroy(ct);
 446
 447         local_bh_disable();
 448         do {
 449                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 450                 hash = hash_conntrack(net,
 451                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 452                 reply_hash = hash_conntrack(net,
 453                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 454         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 455
 456         clean_from_lists(ct);
 457         nf_conntrack_double_unlock(hash, reply_hash);
 458
 459         nf_ct_add_to_dying_list(ct);
 460
 461         local_bh_enable();
 462 }
 463
 464 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 465 {
 466         struct nf_conn_tstamp *tstamp;
 467
 468         if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
 469                 return false;
 470
 471         tstamp = nf_conn_tstamp_find(ct);
 472         if (tstamp && tstamp->stop == 0)
 473                 tstamp->stop = ktime_get_real_ns();
 474
 475         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 476                                     portid, report) < 0) {
 477                 /* destroy event was not delivered. nf_ct_put will
 478                  * be done by event cache worker on redelivery.
 479                  */
 480                 nf_ct_delete_from_lists(ct);
 481                 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
 482                 return false;
 483         }
 484
 485         nf_conntrack_ecache_work(nf_ct_net(ct));
 486         nf_ct_delete_from_lists(ct);
 487         nf_ct_put(ct);
 488         return true;
 489 }
 490 EXPORT_SYMBOL_GPL(nf_ct_delete);
 491
 492 static inline bool
 493 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 494                 const struct nf_conntrack_tuple *tuple,
 495                 const struct nf_conntrack_zone *zone,
 496                 const struct net *net)
 497 {
 498         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 499
 500         /* A conntrack can be recreated with the equal tuple,
 501          * so we need to check that the conntrack is confirmed
 502          */
 503         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 504                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 505                nf_ct_is_confirmed(ct) &&
 506                net_eq(net, nf_ct_net(ct));
 507 }
 508
 509 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
 510 static void nf_ct_gc_expired(struct nf_conn *ct)
 511 {
 512         if (!atomic_inc_not_zero(&ct->ct_general.use))
 513                 return;
 514
 515         if (nf_ct_should_gc(ct))
 516                 nf_ct_kill(ct);
 517
 518         nf_ct_put(ct);
 519 }
 520
 521 /*
 522  * Warning :
 523  * - Caller must take a reference on returned object
 524  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 525  */
 526 static struct nf_conntrack_tuple_hash *
 527 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 528                       const struct nf_conntrack_tuple *tuple, u32 hash)
 529 {
 530         struct nf_conntrack_tuple_hash *h;
 531         struct hlist_nulls_head *ct_hash;
 532         struct hlist_nulls_node *n;
 533         unsigned int bucket, hsize;
 534
 535 begin:
 536         nf_conntrack_get_ht(&ct_hash, &hsize);
 537         bucket = reciprocal_scale(hash, hsize);
 538
 539         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
 540                 struct nf_conn *ct;
 541
 542                 ct = nf_ct_tuplehash_to_ctrack(h);
 543                 if (nf_ct_is_expired(ct)) {
 544                         nf_ct_gc_expired(ct);
 545                         continue;
 546                 }
 547
 548                 if (nf_ct_is_dying(ct))
 549                         continue;
 550
 551                 if (nf_ct_key_equal(h, tuple, zone, net))
 552                         return h;
 553         }
 554         /*
 555          * if the nulls value we got at the end of this lookup is
 556          * not the expected one, we must restart lookup.
 557          * We probably met an item that was moved to another chain.
 558          */
 559         if (get_nulls_value(n) != bucket) {
 560                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 561                 goto begin;
 562         }
 563
 564         return NULL;
 565 }
 566
 567 /* Find a connection corresponding to a tuple. */
 568 static struct nf_conntrack_tuple_hash *
 569 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 570                         const struct nf_conntrack_tuple *tuple, u32 hash)
 571 {
 572         struct nf_conntrack_tuple_hash *h;
 573         struct nf_conn *ct;
 574
 575         rcu_read_lock();
 576 begin:
 577         h = ____nf_conntrack_find(net, zone, tuple, hash);
 578         if (h) {
 579                 ct = nf_ct_tuplehash_to_ctrack(h);
 580                 if (unlikely(nf_ct_is_dying(ct) ||
 581                              !atomic_inc_not_zero(&ct->ct_general.use)))
 582                         h = NULL;
 583                 else {
 584                         if (unlikely(!nf_ct_key_equal(h, tuple, zone, net))) {
 585                                 nf_ct_put(ct);
 586                                 goto begin;
 587                         }
 588                 }
 589         }
 590         rcu_read_unlock();
 591
 592         return h;
 593 }
 594
 595 struct nf_conntrack_tuple_hash *
 596 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 597                       const struct nf_conntrack_tuple *tuple)
 598 {
 599         return __nf_conntrack_find_get(net, zone, tuple,
 600                                        hash_conntrack_raw(tuple, net));
 601 }
 602 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 603
 604 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 605                                        unsigned int hash,
 606                                        unsigned int reply_hash)
 607 {
 608         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 609                            &nf_conntrack_hash[hash]);
 610         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 611                            &nf_conntrack_hash[reply_hash]);
 612 }
 613
 614 int
 615 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 616 {
 617         const struct nf_conntrack_zone *zone;
 618         struct net *net = nf_ct_net(ct);
 619         unsigned int hash, reply_hash;
 620         struct nf_conntrack_tuple_hash *h;
 621         struct hlist_nulls_node *n;
 622         unsigned int sequence;
 623
 624         zone = nf_ct_zone(ct);
 625
 626         local_bh_disable();
 627         do {
 628                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 629                 hash = hash_conntrack(net,
 630                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 631                 reply_hash = hash_conntrack(net,
 632                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 633         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 634
 635         /* See if there's one in the list already, including reverse */
 636         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
 637                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 638                                     zone, net))
 639                         goto out;
 640
 641         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
 642                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 643                                     zone, net))
 644                         goto out;
 645
 646         smp_wmb();
 647         /* The caller holds a reference to this object */
 648         atomic_set(&ct->ct_general.use, 2);
 649         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 650         nf_conntrack_double_unlock(hash, reply_hash);
 651         NF_CT_STAT_INC(net, insert);
 652         local_bh_enable();
 653         return 0;
 654
 655 out:
 656         nf_conntrack_double_unlock(hash, reply_hash);
 657         NF_CT_STAT_INC(net, insert_failed);
 658         local_bh_enable();
 659         return -EEXIST;
 660 }
 661 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 662
 663 static inline void nf_ct_acct_update(struct nf_conn *ct,
 664                                      enum ip_conntrack_info ctinfo,
 665                                      unsigned int len)
 666 {
 667         struct nf_conn_acct *acct;
 668
 669         acct = nf_conn_acct_find(ct);
 670         if (acct) {
 671                 struct nf_conn_counter *counter = acct->counter;
 672
 673                 atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
 674                 atomic64_add(len, &counter[CTINFO2DIR(ctinfo)].bytes);
 675         }
 676 }
 677
 678 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 679                              const struct nf_conn *loser_ct)
 680 {
 681         struct nf_conn_acct *acct;
 682
 683         acct = nf_conn_acct_find(loser_ct);
 684         if (acct) {
 685                 struct nf_conn_counter *counter = acct->counter;
 686                 unsigned int bytes;
 687
 688                 /* u32 should be fine since we must have seen one packet. */
 689                 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
 690                 nf_ct_acct_update(ct, ctinfo, bytes);
 691         }
 692 }
 693
 694 /* Resolve race on insertion if this protocol allows this. */
 695 static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb,
 696                                enum ip_conntrack_info ctinfo,
 697                                struct nf_conntrack_tuple_hash *h)
 698 {
 699         /* This is the conntrack entry already in hashes that won race. */
 700         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 701         struct nf_conntrack_l4proto *l4proto;
 702
 703         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 704         if (l4proto->allow_clash &&
 705             !nfct_nat(ct) &&
 706             !nf_ct_is_dying(ct) &&
 707             atomic_inc_not_zero(&ct->ct_general.use)) {
 708                 enum ip_conntrack_info oldinfo;
 709                 struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo);
 710
 711                 nf_ct_acct_merge(ct, ctinfo, loser_ct);
 712                 nf_conntrack_put(&loser_ct->ct_general);
 713                 nf_ct_set(skb, ct, oldinfo);
 714                 return NF_ACCEPT;
 715         }
 716         NF_CT_STAT_INC(net, drop);
 717         return NF_DROP;
 718 }
 719
 720 /* Confirm a connection given skb; places it in hash table */
 721 int
 722 __nf_conntrack_confirm(struct sk_buff *skb)
 723 {
 724         const struct nf_conntrack_zone *zone;
 725         unsigned int hash, reply_hash;
 726         struct nf_conntrack_tuple_hash *h;
 727         struct nf_conn *ct;
 728         struct nf_conn_help *help;
 729         struct nf_conn_tstamp *tstamp;
 730         struct hlist_nulls_node *n;
 731         enum ip_conntrack_info ctinfo;
 732         struct net *net;
 733         unsigned int sequence;
 734         int ret = NF_DROP;
 735
 736         ct = nf_ct_get(skb, &ctinfo);
 737         net = nf_ct_net(ct);
 738
 739         /* ipt_REJECT uses nf_conntrack_attach to attach related
 740            ICMP/TCP RST packets in other direction.  Actual packet
 741            which created connection will be IP_CT_NEW or for an
 742            expected connection, IP_CT_RELATED. */
 743         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 744                 return NF_ACCEPT;
 745
 746         zone = nf_ct_zone(ct);
 747         local_bh_disable();
 748
 749         do {
 750                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 751                 /* reuse the hash saved before */
 752                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 753                 hash = scale_hash(hash);
 754                 reply_hash = hash_conntrack(net,
 755                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 756
 757         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 758
 759         /* We're not in hash table, and we refuse to set up related
 760          * connections for unconfirmed conns.  But packet copies and
 761          * REJECT will give spurious warnings here.
 762          */
 763         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 764
 765         /* No external references means no one else could have
 766          * confirmed us.
 767          */
 768         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 769         pr_debug("Confirming conntrack %p\n", ct);
 770         /* We have to check the DYING flag after unlink to prevent
 771          * a race against nf_ct_get_next_corpse() possibly called from
 772          * user context, else we insert an already 'dead' hash, blocking
 773          * further use of that particular connection -JM.
 774          */
 775         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 776
 777         if (unlikely(nf_ct_is_dying(ct))) {
 778                 nf_ct_add_to_dying_list(ct);
 779                 goto dying;
 780         }
 781
 782         /* See if there's one in the list already, including reverse:
 783            NAT could have grabbed it without realizing, since we're
 784            not in the hash.  If there is, we lost race. */
 785         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
 786                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 787                                     zone, net))
 788                         goto out;
 789
 790         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
 791                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 792                                     zone, net))
 793                         goto out;
 794
 795         /* Timer relative to confirmation time, not original
 796            setting time, otherwise we'd get timer wrap in
 797            weird delay cases. */
 798         ct->timeout += nfct_time_stamp;
 799         atomic_inc(&ct->ct_general.use);
 800         ct->status |= IPS_CONFIRMED;
 801
 802         /* set conntrack timestamp, if enabled. */
 803         tstamp = nf_conn_tstamp_find(ct);
 804         if (tstamp) {
 805                 if (skb->tstamp == 0)
 806                         __net_timestamp(skb);
 807
 808                 tstamp->start = ktime_to_ns(skb->tstamp);
 809         }
 810         /* Since the lookup is lockless, hash insertion must be done after
 811          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 812          * guarantee that no other CPU can find the conntrack before the above
 813          * stores are visible.
 814          */
 815         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 816         nf_conntrack_double_unlock(hash, reply_hash);
 817         local_bh_enable();
 818
 819         help = nfct_help(ct);
 820         if (help && help->helper)
 821                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 822
 823         nf_conntrack_event_cache(master_ct(ct) ?
 824                                  IPCT_RELATED : IPCT_NEW, ct);
 825         return NF_ACCEPT;
 826
 827 out:
 828         nf_ct_add_to_dying_list(ct);
 829         ret = nf_ct_resolve_clash(net, skb, ctinfo, h);
 830 dying:
 831         nf_conntrack_double_unlock(hash, reply_hash);
 832         NF_CT_STAT_INC(net, insert_failed);
 833         local_bh_enable();
 834         return ret;
 835 }
 836 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 837
 838 /* Returns true if a connection correspondings to the tuple (required
 839    for NAT). */
 840 int
 841 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 842                          const struct nf_conn *ignored_conntrack)
 843 {
 844         struct net *net = nf_ct_net(ignored_conntrack);
 845         const struct nf_conntrack_zone *zone;
 846         struct nf_conntrack_tuple_hash *h;
 847         struct hlist_nulls_head *ct_hash;
 848         unsigned int hash, hsize;
 849         struct hlist_nulls_node *n;
 850         struct nf_conn *ct;
 851
 852         zone = nf_ct_zone(ignored_conntrack);
 853
 854         rcu_read_lock();
 855  begin:
 856         nf_conntrack_get_ht(&ct_hash, &hsize);
 857         hash = __hash_conntrack(net, tuple, hsize);
 858
 859         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
 860                 ct = nf_ct_tuplehash_to_ctrack(h);
 861
 862                 if (ct == ignored_conntrack)
 863                         continue;
 864
 865                 if (nf_ct_is_expired(ct)) {
 866                         nf_ct_gc_expired(ct);
 867                         continue;
 868                 }
 869
 870                 if (nf_ct_key_equal(h, tuple, zone, net)) {
 871                         NF_CT_STAT_INC_ATOMIC(net, found);
 872                         rcu_read_unlock();
 873                         return 1;
 874                 }
 875         }
 876
 877         if (get_nulls_value(n) != hash) {
 878                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 879                 goto begin;
 880         }
 881
 882         rcu_read_unlock();
 883
 884         return 0;
 885 }
 886 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 887
 888 #define NF_CT_EVICTION_RANGE    8
 889
 890 /* There's a small race here where we may free a just-assured
 891    connection.  Too bad: we're in trouble anyway. */
 892 static unsigned int early_drop_list(struct net *net,
 893                                     struct hlist_nulls_head *head)
 894 {
 895         struct nf_conntrack_tuple_hash *h;
 896         struct hlist_nulls_node *n;
 897         unsigned int drops = 0;
 898         struct nf_conn *tmp;
 899
 900         hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
 901                 tmp = nf_ct_tuplehash_to_ctrack(h);
 902
 903                 if (nf_ct_is_expired(tmp)) {
 904                         nf_ct_gc_expired(tmp);
 905                         continue;
 906                 }
 907
 908                 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
 909                     !net_eq(nf_ct_net(tmp), net) ||
 910                     nf_ct_is_dying(tmp))
 911                         continue;
 912
 913                 if (!atomic_inc_not_zero(&tmp->ct_general.use))
 914                         continue;
 915
 916                 /* kill only if still in same netns -- might have moved due to
 917                  * SLAB_DESTROY_BY_RCU rules.
 918                  *
 919                  * We steal the timer reference.  If that fails timer has
 920                  * already fired or someone else deleted it. Just drop ref
 921                  * and move to next entry.
 922                  */
 923                 if (net_eq(nf_ct_net(tmp), net) &&
 924                     nf_ct_is_confirmed(tmp) &&
 925                     nf_ct_delete(tmp, 0, 0))
 926                         drops++;
 927
 928                 nf_ct_put(tmp);
 929         }
 930
 931         return drops;
 932 }
 933
 934 static noinline int early_drop(struct net *net, unsigned int _hash)
 935 {
 936         unsigned int i;
 937
 938         for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
 939                 struct hlist_nulls_head *ct_hash;
 940                 unsigned int hash, hsize, drops;
 941
 942                 rcu_read_lock();
 943                 nf_conntrack_get_ht(&ct_hash, &hsize);
 944                 hash = reciprocal_scale(_hash++, hsize);
 945
 946                 drops = early_drop_list(net, &ct_hash[hash]);
 947                 rcu_read_unlock();
 948
 949                 if (drops) {
 950                         NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
 951                         return true;
 952                 }
 953         }
 954
 955         return false;
 956 }
 957
 958 static void gc_worker(struct work_struct *work)
 959 {
 960         unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
 961         unsigned int i, goal, buckets = 0, expired_count = 0;
 962         struct conntrack_gc_work *gc_work;
 963         unsigned int ratio, scanned = 0;
 964         unsigned long next_run;
 965
 966         gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
 967
 968         goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
 969         i = gc_work->last_bucket;
 970
 971         do {
 972                 struct nf_conntrack_tuple_hash *h;
 973                 struct hlist_nulls_head *ct_hash;
 974                 struct hlist_nulls_node *n;
 975                 unsigned int hashsz;
 976                 struct nf_conn *tmp;
 977
 978                 i++;
 979                 rcu_read_lock();
 980
 981                 nf_conntrack_get_ht(&ct_hash, &hashsz);
 982                 if (i >= hashsz)
 983                         i = 0;
 984
 985                 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
 986                         tmp = nf_ct_tuplehash_to_ctrack(h);
 987
 988                         scanned++;
 989                         if (nf_ct_is_expired(tmp)) {
 990                                 nf_ct_gc_expired(tmp);
 991                                 expired_count++;
 992                                 continue;
 993                         }
 994                 }
 995
 996                 /* could check get_nulls_value() here and restart if ct
 997                  * was moved to another chain.  But given gc is best-effort
 998                  * we will just continue with next hash slot.
 999                  */
1000                 rcu_read_unlock();
1001                 cond_resched_rcu_qs();
1002         } while (++buckets < goal);
1003
1004         if (gc_work->exiting)
1005                 return;
1006
1007         /*
1008          * Eviction will normally happen from the packet path, and not
1009          * from this gc worker.
1010          *
1011          * This worker is only here to reap expired entries when system went
1012          * idle after a busy period.
1013          *
1014          * The heuristics below are supposed to balance conflicting goals:
1015          *
1016          * 1. Minimize time until we notice a stale entry
1017          * 2. Maximize scan intervals to not waste cycles
1018          *
1019          * Normally, expire ratio will be close to 0.
1020          *
1021          * As soon as a sizeable fraction of the entries have expired
1022          * increase scan frequency.
1023          */
1024         ratio = scanned ? expired_count * 100 / scanned : 0;
1025         if (ratio > GC_EVICT_RATIO) {
1026                 gc_work->next_gc_run = min_interval;
1027         } else {
1028                 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1029
1030                 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1031
1032                 gc_work->next_gc_run += min_interval;
1033                 if (gc_work->next_gc_run > max)
1034                         gc_work->next_gc_run = max;
1035         }
1036
1037         next_run = gc_work->next_gc_run;
1038         gc_work->last_bucket = i;
1039         queue_delayed_work(system_long_wq, &gc_work->dwork, next_run);
1040 }
1041
1042 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1043 {
1044         INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
1045         gc_work->next_gc_run = HZ;
1046         gc_work->exiting = false;
1047 }
1048
1049 static struct nf_conn *
1050 __nf_conntrack_alloc(struct net *net,
1051                      const struct nf_conntrack_zone *zone,
1052                      const struct nf_conntrack_tuple *orig,
1053                      const struct nf_conntrack_tuple *repl,
1054                      gfp_t gfp, u32 hash)
1055 {
1056         struct nf_conn *ct;
1057
1058         /* We don't want any race condition at early drop stage */
1059         atomic_inc(&net->ct.count);
1060
1061         if (nf_conntrack_max &&
1062             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
1063                 if (!early_drop(net, hash)) {
1064                         atomic_dec(&net->ct.count);
1065                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1066                         return ERR_PTR(-ENOMEM);
1067                 }
1068         }
1069
1070         /*
1071          * Do not use kmem_cache_zalloc(), as this cache uses
1072          * SLAB_DESTROY_BY_RCU.
1073          */
1074         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1075         if (ct == NULL)
1076                 goto out;
1077
1078         spin_lock_init(&ct->lock);
1079         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1080         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1081         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1082         /* save hash for reusing when confirming */
1083         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1084         ct->status = 0;
1085         write_pnet(&ct->ct_net, net);
1086         memset(&ct->__nfct_init_offset[0], 0,
1087                offsetof(struct nf_conn, proto) -
1088                offsetof(struct nf_conn, __nfct_init_offset[0]));
1089
1090         nf_ct_zone_add(ct, zone);
1091
1092         /* Because we use RCU lookups, we set ct_general.use to zero before
1093          * this is inserted in any list.
1094          */
1095         atomic_set(&ct->ct_general.use, 0);
1096         return ct;
1097 out:
1098         atomic_dec(&net->ct.count);
1099         return ERR_PTR(-ENOMEM);
1100 }
1101
1102 struct nf_conn *nf_conntrack_alloc(struct net *net,
1103                                    const struct nf_conntrack_zone *zone,
1104                                    const struct nf_conntrack_tuple *orig,
1105                                    const struct nf_conntrack_tuple *repl,
1106                                    gfp_t gfp)
1107 {
1108         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1109 }
1110 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1111
1112 void nf_conntrack_free(struct nf_conn *ct)
1113 {
1114         struct net *net = nf_ct_net(ct);
1115
1116         /* A freed object has refcnt == 0, that's
1117          * the golden rule for SLAB_DESTROY_BY_RCU
1118          */
1119         NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 0);
1120
1121         nf_ct_ext_destroy(ct);
1122         nf_ct_ext_free(ct);
1123         kmem_cache_free(nf_conntrack_cachep, ct);
1124         smp_mb__before_atomic();
1125         atomic_dec(&net->ct.count);
1126 }
1127 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1128
1129
1130 /* Allocate a new conntrack: we return -ENOMEM if classification
1131    failed due to stress.  Otherwise it really is unclassifiable. */
1132 static struct nf_conntrack_tuple_hash *
1133 init_conntrack(struct net *net, struct nf_conn *tmpl,
1134                const struct nf_conntrack_tuple *tuple,
1135                struct nf_conntrack_l3proto *l3proto,
1136                struct nf_conntrack_l4proto *l4proto,
1137                struct sk_buff *skb,
1138                unsigned int dataoff, u32 hash)
1139 {
1140         struct nf_conn *ct;
1141         struct nf_conn_help *help;
1142         struct nf_conntrack_tuple repl_tuple;
1143         struct nf_conntrack_ecache *ecache;
1144         struct nf_conntrack_expect *exp = NULL;
1145         const struct nf_conntrack_zone *zone;
1146         struct nf_conn_timeout *timeout_ext;
1147         struct nf_conntrack_zone tmp;
1148         unsigned int *timeouts;
1149
1150         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
1151                 pr_debug("Can't invert tuple.\n");
1152                 return NULL;
1153         }
1154
1155         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1156         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1157                                   hash);
1158         if (IS_ERR(ct))
1159                 return (struct nf_conntrack_tuple_hash *)ct;
1160
1161         if (!nf_ct_add_synproxy(ct, tmpl)) {
1162                 nf_conntrack_free(ct);
1163                 return ERR_PTR(-ENOMEM);
1164         }
1165
1166         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1167         if (timeout_ext) {
1168                 timeouts = nf_ct_timeout_data(timeout_ext);
1169                 if (unlikely(!timeouts))
1170                         timeouts = l4proto->get_timeouts(net);
1171         } else {
1172                 timeouts = l4proto->get_timeouts(net);
1173         }
1174
1175         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
1176                 nf_conntrack_free(ct);
1177                 pr_debug("can't track with proto module\n");
1178                 return NULL;
1179         }
1180
1181         if (timeout_ext)
1182                 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1183                                       GFP_ATOMIC);
1184
1185         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1186         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1187         nf_ct_labels_ext_add(ct);
1188
1189         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1190         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1191                                  ecache ? ecache->expmask : 0,
1192                              GFP_ATOMIC);
1193
1194         local_bh_disable();
1195         if (net->ct.expect_count) {
1196                 spin_lock(&nf_conntrack_expect_lock);
1197                 exp = nf_ct_find_expectation(net, zone, tuple);
1198                 if (exp) {
1199                         pr_debug("expectation arrives ct=%p exp=%p\n",
1200                                  ct, exp);
1201                         /* Welcome, Mr. Bond.  We've been expecting you... */
1202                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
1203                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1204                         ct->master = exp->master;
1205                         if (exp->helper) {
1206                                 help = nf_ct_helper_ext_add(ct, exp->helper,
1207                                                             GFP_ATOMIC);
1208                                 if (help)
1209                                         rcu_assign_pointer(help->helper, exp->helper);
1210                         }
1211
1212 #ifdef CONFIG_NF_CONNTRACK_MARK
1213                         ct->mark = exp->master->mark;
1214 #endif
1215 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1216                         ct->secmark = exp->master->secmark;
1217 #endif
1218                         NF_CT_STAT_INC(net, expect_new);
1219                 }
1220                 spin_unlock(&nf_conntrack_expect_lock);
1221         }
1222         if (!exp)
1223                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1224
1225         /* Now it is inserted into the unconfirmed list, bump refcount */
1226         nf_conntrack_get(&ct->ct_general);
1227         nf_ct_add_to_unconfirmed_list(ct);
1228
1229         local_bh_enable();
1230
1231         if (exp) {
1232                 if (exp->expectfn)
1233                         exp->expectfn(ct, exp);
1234                 nf_ct_expect_put(exp);
1235         }
1236
1237         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1238 }
1239
1240 /* On success, returns conntrack ptr, sets skb->_nfct | ctinfo */
1241 static inline struct nf_conn *
1242 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
1243                   struct sk_buff *skb,
1244                   unsigned int dataoff,
1245                   u_int16_t l3num,
1246                   u_int8_t protonum,
1247                   struct nf_conntrack_l3proto *l3proto,
1248                   struct nf_conntrack_l4proto *l4proto,
1249                   int *set_reply,
1250                   enum ip_conntrack_info *ctinfo)
1251 {
1252         const struct nf_conntrack_zone *zone;
1253         struct nf_conntrack_tuple tuple;
1254         struct nf_conntrack_tuple_hash *h;
1255         struct nf_conntrack_zone tmp;
1256         struct nf_conn *ct;
1257         u32 hash;
1258
1259         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1260                              dataoff, l3num, protonum, net, &tuple, l3proto,
1261                              l4proto)) {
1262                 pr_debug("Can't get tuple\n");
1263                 return NULL;
1264         }
1265
1266         /* look for tuple match */
1267         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1268         hash = hash_conntrack_raw(&tuple, net);
1269         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
1270         if (!h) {
1271                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
1272                                    skb, dataoff, hash);
1273                 if (!h)
1274                         return NULL;
1275                 if (IS_ERR(h))
1276                         return (void *)h;
1277         }
1278         ct = nf_ct_tuplehash_to_ctrack(h);
1279
1280         /* It exists; we have (non-exclusive) reference. */
1281         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1282                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
1283                 /* Please set reply bit if this packet OK */
1284                 *set_reply = 1;
1285         } else {
1286                 /* Once we've had two way comms, always ESTABLISHED. */
1287                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1288                         pr_debug("normal packet for %p\n", ct);
1289                         *ctinfo = IP_CT_ESTABLISHED;
1290                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1291                         pr_debug("related packet for %p\n", ct);
1292                         *ctinfo = IP_CT_RELATED;
1293                 } else {
1294                         pr_debug("new packet for %p\n", ct);
1295                         *ctinfo = IP_CT_NEW;
1296                 }
1297                 *set_reply = 0;
1298         }
1299         nf_ct_set(skb, ct, *ctinfo);
1300         return ct;
1301 }
1302
1303 unsigned int
1304 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
1305                 struct sk_buff *skb)
1306 {
1307         struct nf_conn *ct, *tmpl;
1308         enum ip_conntrack_info ctinfo;
1309         struct nf_conntrack_l3proto *l3proto;
1310         struct nf_conntrack_l4proto *l4proto;
1311         unsigned int *timeouts;
1312         unsigned int dataoff;
1313         u_int8_t protonum;
1314         int set_reply = 0;
1315         int ret;
1316
1317         tmpl = nf_ct_get(skb, &ctinfo);
1318         if (tmpl) {
1319                 /* Previously seen (loopback or untracked)?  Ignore. */
1320                 if (!nf_ct_is_template(tmpl)) {
1321                         NF_CT_STAT_INC_ATOMIC(net, ignore);
1322                         return NF_ACCEPT;
1323                 }
1324                 skb->_nfct = 0;
1325         }
1326
1327         /* rcu_read_lock()ed by nf_hook_thresh */
1328         l3proto = __nf_ct_l3proto_find(pf);
1329         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
1330                                    &dataoff, &protonum);
1331         if (ret <= 0) {
1332                 pr_debug("not prepared to track yet or error occurred\n");
1333                 NF_CT_STAT_INC_ATOMIC(net, error);
1334                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1335                 ret = -ret;
1336                 goto out;
1337         }
1338
1339         l4proto = __nf_ct_l4proto_find(pf, protonum);
1340
1341         /* It may be an special packet, error, unclean...
1342          * inverse of the return code tells to the netfilter
1343          * core what to do with the packet. */
1344         if (l4proto->error != NULL) {
1345                 ret = l4proto->error(net, tmpl, skb, dataoff, pf, hooknum);
1346                 if (ret <= 0) {
1347                         NF_CT_STAT_INC_ATOMIC(net, error);
1348                         NF_CT_STAT_INC_ATOMIC(net, invalid);
1349                         ret = -ret;
1350                         goto out;
1351                 }
1352                 /* ICMP[v6] protocol trackers may assign one conntrack. */
1353                 if (skb->_nfct)
1354                         goto out;
1355         }
1356 repeat:
1357         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
1358                                l3proto, l4proto, &set_reply, &ctinfo);
1359         if (!ct) {
1360                 /* Not valid part of a connection */
1361                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1362                 ret = NF_ACCEPT;
1363                 goto out;
1364         }
1365
1366         if (IS_ERR(ct)) {
1367                 /* Too stressed to deal. */
1368                 NF_CT_STAT_INC_ATOMIC(net, drop);
1369                 ret = NF_DROP;
1370                 goto out;
1371         }
1372
1373         NF_CT_ASSERT(skb_nfct(skb));
1374
1375         /* Decide what timeout policy we want to apply to this flow. */
1376         timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1377
1378         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1379         if (ret <= 0) {
1380                 /* Invalid: inverse of the return code tells
1381                  * the netfilter core what to do */
1382                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1383                 nf_conntrack_put(&ct->ct_general);
1384                 skb->_nfct = 0;
1385                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1386                 if (ret == -NF_DROP)
1387                         NF_CT_STAT_INC_ATOMIC(net, drop);
1388                 /* Special case: TCP tracker reports an attempt to reopen a
1389                  * closed/aborted connection. We have to go back and create a
1390                  * fresh conntrack.
1391                  */
1392                 if (ret == -NF_REPEAT)
1393                         goto repeat;
1394                 ret = -ret;
1395                 goto out;
1396         }
1397
1398         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1399                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1400 out:
1401         if (tmpl)
1402                 nf_ct_put(tmpl);
1403
1404         return ret;
1405 }
1406 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1407
1408 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1409                           const struct nf_conntrack_tuple *orig)
1410 {
1411         bool ret;
1412
1413         rcu_read_lock();
1414         ret = nf_ct_invert_tuple(inverse, orig,
1415                                  __nf_ct_l3proto_find(orig->src.l3num),
1416                                  __nf_ct_l4proto_find(orig->src.l3num,
1417                                                       orig->dst.protonum));
1418         rcu_read_unlock();
1419         return ret;
1420 }
1421 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1422
1423 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1424    implicitly racy: see __nf_conntrack_confirm */
1425 void nf_conntrack_alter_reply(struct nf_conn *ct,
1426                               const struct nf_conntrack_tuple *newreply)
1427 {
1428         struct nf_conn_help *help = nfct_help(ct);
1429
1430         /* Should be unconfirmed, so not in hash table yet */
1431         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1432
1433         pr_debug("Altering reply tuple of %p to ", ct);
1434         nf_ct_dump_tuple(newreply);
1435
1436         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1437         if (ct->master || (help && !hlist_empty(&help->expectations)))
1438                 return;
1439
1440         rcu_read_lock();
1441         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1442         rcu_read_unlock();
1443 }
1444 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1445
1446 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1447 void __nf_ct_refresh_acct(struct nf_conn *ct,
1448                           enum ip_conntrack_info ctinfo,
1449                           const struct sk_buff *skb,
1450                           unsigned long extra_jiffies,
1451                           int do_acct)
1452 {
1453         NF_CT_ASSERT(skb);
1454
1455         /* Only update if this is not a fixed timeout */
1456         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1457                 goto acct;
1458
1459         /* If not in hash table, timer will not be active yet */
1460         if (nf_ct_is_confirmed(ct))
1461                 extra_jiffies += nfct_time_stamp;
1462
1463         ct->timeout = extra_jiffies;
1464 acct:
1465         if (do_acct)
1466                 nf_ct_acct_update(ct, ctinfo, skb->len);
1467 }
1468 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1469
1470 bool nf_ct_kill_acct(struct nf_conn *ct,
1471                      enum ip_conntrack_info ctinfo,
1472                      const struct sk_buff *skb)
1473 {
1474         nf_ct_acct_update(ct, ctinfo, skb->len);
1475
1476         return nf_ct_delete(ct, 0, 0);
1477 }
1478 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1479
1480 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1481
1482 #include <linux/netfilter/nfnetlink.h>
1483 #include <linux/netfilter/nfnetlink_conntrack.h>
1484 #include <linux/mutex.h>
1485
1486 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1487  * in ip_conntrack_core, since we don't want the protocols to autoload
1488  * or depend on ctnetlink */
1489 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1490                                const struct nf_conntrack_tuple *tuple)
1491 {
1492         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1493             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1494                 goto nla_put_failure;
1495         return 0;
1496
1497 nla_put_failure:
1498         return -1;
1499 }
1500 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1501
1502 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1503         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1504         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1505 };
1506 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1507
1508 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1509                                struct nf_conntrack_tuple *t)
1510 {
1511         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1512                 return -EINVAL;
1513
1514         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1515         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1516
1517         return 0;
1518 }
1519 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1520
1521 int nf_ct_port_nlattr_tuple_size(void)
1522 {
1523         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1524 }
1525 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1526 #endif
1527
1528 /* Used by ipt_REJECT and ip6t_REJECT. */
1529 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1530 {
1531         struct nf_conn *ct;
1532         enum ip_conntrack_info ctinfo;
1533
1534         /* This ICMP is in reverse direction to the packet which caused it */
1535         ct = nf_ct_get(skb, &ctinfo);
1536         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1537                 ctinfo = IP_CT_RELATED_REPLY;
1538         else
1539                 ctinfo = IP_CT_RELATED;
1540
1541         /* Attach to new skbuff, and increment count */
1542         nf_ct_set(nskb, ct, ctinfo);
1543         nf_conntrack_get(skb_nfct(nskb));
1544 }
1545
1546 /* Bring out ya dead! */
1547 static struct nf_conn *
1548 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1549                 void *data, unsigned int *bucket)
1550 {
1551         struct nf_conntrack_tuple_hash *h;
1552         struct nf_conn *ct;
1553         struct hlist_nulls_node *n;
1554         int cpu;
1555         spinlock_t *lockp;
1556
1557         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1558                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
1559                 local_bh_disable();
1560                 nf_conntrack_lock(lockp);
1561                 if (*bucket < nf_conntrack_htable_size) {
1562                         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
1563                                 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
1564                                         continue;
1565                                 ct = nf_ct_tuplehash_to_ctrack(h);
1566                                 if (net_eq(nf_ct_net(ct), net) &&
1567                                     iter(ct, data))
1568                                         goto found;
1569                         }
1570                 }
1571                 spin_unlock(lockp);
1572                 local_bh_enable();
1573                 cond_resched();
1574         }
1575
1576         for_each_possible_cpu(cpu) {
1577                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1578
1579                 spin_lock_bh(&pcpu->lock);
1580                 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
1581                         ct = nf_ct_tuplehash_to_ctrack(h);
1582                         if (iter(ct, data))
1583                                 set_bit(IPS_DYING_BIT, &ct->status);
1584                 }
1585                 spin_unlock_bh(&pcpu->lock);
1586                 cond_resched();
1587         }
1588         return NULL;
1589 found:
1590         atomic_inc(&ct->ct_general.use);
1591         spin_unlock(lockp);
1592         local_bh_enable();
1593         return ct;
1594 }
1595
1596 void nf_ct_iterate_cleanup(struct net *net,
1597                            int (*iter)(struct nf_conn *i, void *data),
1598                            void *data, u32 portid, int report)
1599 {
1600         struct nf_conn *ct;
1601         unsigned int bucket = 0;
1602
1603         might_sleep();
1604
1605         if (atomic_read(&net->ct.count) == 0)
1606                 return;
1607
1608         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1609                 /* Time to push up daises... */
1610
1611                 nf_ct_delete(ct, portid, report);
1612                 nf_ct_put(ct);
1613                 cond_resched();
1614         }
1615 }
1616 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1617
1618 static int kill_all(struct nf_conn *i, void *data)
1619 {
1620         return 1;
1621 }
1622
1623 void nf_ct_free_hashtable(void *hash, unsigned int size)
1624 {
1625         if (is_vmalloc_addr(hash))
1626                 vfree(hash);
1627         else
1628                 free_pages((unsigned long)hash,
1629                            get_order(sizeof(struct hlist_head) * size));
1630 }
1631 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1632
1633 static int untrack_refs(void)
1634 {
1635         int cnt = 0, cpu;
1636
1637         for_each_possible_cpu(cpu) {
1638                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1639
1640                 cnt += atomic_read(&ct->ct_general.use) - 1;
1641         }
1642         return cnt;
1643 }
1644
1645 void nf_conntrack_cleanup_start(void)
1646 {
1647         conntrack_gc_work.exiting = true;
1648         RCU_INIT_POINTER(ip_ct_attach, NULL);
1649 }
1650
1651 void nf_conntrack_cleanup_end(void)
1652 {
1653         RCU_INIT_POINTER(nf_ct_destroy, NULL);
1654         while (untrack_refs() > 0)
1655                 schedule();
1656
1657         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
1658         nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size);
1659
1660         nf_conntrack_proto_fini();
1661         nf_conntrack_seqadj_fini();
1662         nf_conntrack_labels_fini();
1663         nf_conntrack_helper_fini();
1664         nf_conntrack_timeout_fini();
1665         nf_conntrack_ecache_fini();
1666         nf_conntrack_tstamp_fini();
1667         nf_conntrack_acct_fini();
1668         nf_conntrack_expect_fini();
1669
1670         kmem_cache_destroy(nf_conntrack_cachep);
1671 }
1672
1673 /*
1674  * Mishearing the voices in his head, our hero wonders how he's
1675  * supposed to kill the mall.
1676  */
1677 void nf_conntrack_cleanup_net(struct net *net)
1678 {
1679         LIST_HEAD(single);
1680
1681         list_add(&net->exit_list, &single);
1682         nf_conntrack_cleanup_net_list(&single);
1683 }
1684
1685 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
1686 {
1687         int busy;
1688         struct net *net;
1689
1690         /*
1691          * This makes sure all current packets have passed through
1692          *  netfilter framework.  Roll on, two-stage module
1693          *  delete...
1694          */
1695         synchronize_net();
1696 i_see_dead_people:
1697         busy = 0;
1698         list_for_each_entry(net, net_exit_list, exit_list) {
1699                 nf_ct_iterate_cleanup(net, kill_all, NULL, 0, 0);
1700                 if (atomic_read(&net->ct.count) != 0)
1701                         busy = 1;
1702         }
1703         if (busy) {
1704                 schedule();
1705                 goto i_see_dead_people;
1706         }
1707
1708         list_for_each_entry(net, net_exit_list, exit_list) {
1709                 nf_conntrack_proto_pernet_fini(net);
1710                 nf_conntrack_helper_pernet_fini(net);
1711                 nf_conntrack_ecache_pernet_fini(net);
1712                 nf_conntrack_tstamp_pernet_fini(net);
1713                 nf_conntrack_acct_pernet_fini(net);
1714                 nf_conntrack_expect_pernet_fini(net);
1715                 free_percpu(net->ct.stat);
1716                 free_percpu(net->ct.pcpu_lists);
1717         }
1718 }
1719
1720 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1721 {
1722         struct hlist_nulls_head *hash;
1723         unsigned int nr_slots, i;
1724         size_t sz;
1725
1726         if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
1727                 return NULL;
1728
1729         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1730         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1731
1732         if (nr_slots > (UINT_MAX / sizeof(struct hlist_nulls_head)))
1733                 return NULL;
1734
1735         sz = nr_slots * sizeof(struct hlist_nulls_head);
1736         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1737                                         get_order(sz));
1738         if (!hash)
1739                 hash = vzalloc(sz);
1740
1741         if (hash && nulls)
1742                 for (i = 0; i < nr_slots; i++)
1743                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1744
1745         return hash;
1746 }
1747 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1748
1749 int nf_conntrack_hash_resize(unsigned int hashsize)
1750 {
1751         int i, bucket;
1752         unsigned int old_size;
1753         struct hlist_nulls_head *hash, *old_hash;
1754         struct nf_conntrack_tuple_hash *h;
1755         struct nf_conn *ct;
1756
1757         if (!hashsize)
1758                 return -EINVAL;
1759
1760         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1761         if (!hash)
1762                 return -ENOMEM;
1763
1764         old_size = nf_conntrack_htable_size;
1765         if (old_size == hashsize) {
1766                 nf_ct_free_hashtable(hash, hashsize);
1767                 return 0;
1768         }
1769
1770         local_bh_disable();
1771         nf_conntrack_all_lock();
1772         write_seqcount_begin(&nf_conntrack_generation);
1773
1774         /* Lookups in the old hash might happen in parallel, which means we
1775          * might get false negatives during connection lookup. New connections
1776          * created because of a false negative won't make it into the hash
1777          * though since that required taking the locks.
1778          */
1779
1780         for (i = 0; i < nf_conntrack_htable_size; i++) {
1781                 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
1782                         h = hlist_nulls_entry(nf_conntrack_hash[i].first,
1783                                               struct nf_conntrack_tuple_hash, hnnode);
1784                         ct = nf_ct_tuplehash_to_ctrack(h);
1785                         hlist_nulls_del_rcu(&h->hnnode);
1786                         bucket = __hash_conntrack(nf_ct_net(ct),
1787                                                   &h->tuple, hashsize);
1788                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1789                 }
1790         }
1791         old_size = nf_conntrack_htable_size;
1792         old_hash = nf_conntrack_hash;
1793
1794         nf_conntrack_hash = hash;
1795         nf_conntrack_htable_size = hashsize;
1796
1797         write_seqcount_end(&nf_conntrack_generation);
1798         nf_conntrack_all_unlock();
1799         local_bh_enable();
1800
1801         synchronize_net();
1802         nf_ct_free_hashtable(old_hash, old_size);
1803         return 0;
1804 }
1805
1806 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1807 {
1808         unsigned int hashsize;
1809         int rc;
1810
1811         if (current->nsproxy->net_ns != &init_net)
1812                 return -EOPNOTSUPP;
1813
1814         /* On boot, we can set this without any fancy locking. */
1815         if (!nf_conntrack_htable_size)
1816                 return param_set_uint(val, kp);
1817
1818         rc = kstrtouint(val, 0, &hashsize);
1819         if (rc)
1820                 return rc;
1821
1822         return nf_conntrack_hash_resize(hashsize);
1823 }
1824 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1825
1826 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1827                   &nf_conntrack_htable_size, 0600);
1828
1829 void nf_ct_untracked_status_or(unsigned long bits)
1830 {
1831         int cpu;
1832
1833         for_each_possible_cpu(cpu)
1834                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1835 }
1836 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1837
1838 int nf_conntrack_init_start(void)
1839 {
1840         int max_factor = 8;
1841         int ret = -ENOMEM;
1842         int i, cpu;
1843
1844         seqcount_init(&nf_conntrack_generation);
1845
1846         for (i = 0; i < CONNTRACK_LOCKS; i++)
1847                 spin_lock_init(&nf_conntrack_locks[i]);
1848
1849         if (!nf_conntrack_htable_size) {
1850                 /* Idea from tcp.c: use 1/16384 of memory.
1851                  * On i386: 32MB machine has 512 buckets.
1852                  * >= 1GB machines have 16384 buckets.
1853                  * >= 4GB machines have 65536 buckets.
1854                  */
1855                 nf_conntrack_htable_size
1856                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1857                            / sizeof(struct hlist_head));
1858                 if (totalram_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
1859                         nf_conntrack_htable_size = 65536;
1860                 else if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1861                         nf_conntrack_htable_size = 16384;
1862                 if (nf_conntrack_htable_size < 32)
1863                         nf_conntrack_htable_size = 32;
1864
1865                 /* Use a max. factor of four by default to get the same max as
1866                  * with the old struct list_heads. When a table size is given
1867                  * we use the old value of 8 to avoid reducing the max.
1868                  * entries. */
1869                 max_factor = 4;
1870         }
1871
1872         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
1873         if (!nf_conntrack_hash)
1874                 return -ENOMEM;
1875
1876         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1877
1878         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1879                                                 sizeof(struct nf_conn),
1880                                                 NFCT_INFOMASK + 1,
1881                                                 SLAB_DESTROY_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
1882         if (!nf_conntrack_cachep)
1883                 goto err_cachep;
1884
1885         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1886                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1887                nf_conntrack_max);
1888
1889         ret = nf_conntrack_expect_init();
1890         if (ret < 0)
1891                 goto err_expect;
1892
1893         ret = nf_conntrack_acct_init();
1894         if (ret < 0)
1895                 goto err_acct;
1896
1897         ret = nf_conntrack_tstamp_init();
1898         if (ret < 0)
1899                 goto err_tstamp;
1900
1901         ret = nf_conntrack_ecache_init();
1902         if (ret < 0)
1903                 goto err_ecache;
1904
1905         ret = nf_conntrack_timeout_init();
1906         if (ret < 0)
1907                 goto err_timeout;
1908
1909         ret = nf_conntrack_helper_init();
1910         if (ret < 0)
1911                 goto err_helper;
1912
1913         ret = nf_conntrack_labels_init();
1914         if (ret < 0)
1915                 goto err_labels;
1916
1917         ret = nf_conntrack_seqadj_init();
1918         if (ret < 0)
1919                 goto err_seqadj;
1920
1921         ret = nf_conntrack_proto_init();
1922         if (ret < 0)
1923                 goto err_proto;
1924
1925         /* Set up fake conntrack: to never be deleted, not in any hashes */
1926         for_each_possible_cpu(cpu) {
1927                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1928                 write_pnet(&ct->ct_net, &init_net);
1929                 atomic_set(&ct->ct_general.use, 1);
1930         }
1931         /*  - and look it like as a confirmed connection */
1932         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1933
1934         conntrack_gc_work_init(&conntrack_gc_work);
1935         queue_delayed_work(system_long_wq, &conntrack_gc_work.dwork, HZ);
1936
1937         return 0;
1938
1939 err_proto:
1940         nf_conntrack_seqadj_fini();
1941 err_seqadj:
1942         nf_conntrack_labels_fini();
1943 err_labels:
1944         nf_conntrack_helper_fini();
1945 err_helper:
1946         nf_conntrack_timeout_fini();
1947 err_timeout:
1948         nf_conntrack_ecache_fini();
1949 err_ecache:
1950         nf_conntrack_tstamp_fini();
1951 err_tstamp:
1952         nf_conntrack_acct_fini();
1953 err_acct:
1954         nf_conntrack_expect_fini();
1955 err_expect:
1956         kmem_cache_destroy(nf_conntrack_cachep);
1957 err_cachep:
1958         nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size);
1959         return ret;
1960 }
1961
1962 void nf_conntrack_init_end(void)
1963 {
1964         /* For use by REJECT target */
1965         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1966         RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1967 }
1968
1969 /*
1970  * We need to use special "null" values, not used in hash table
1971  */
1972 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1973 #define DYING_NULLS_VAL         ((1<<30)+1)
1974 #define TEMPLATE_NULLS_VAL      ((1<<30)+2)
1975
1976 int nf_conntrack_init_net(struct net *net)
1977 {
1978         int ret = -ENOMEM;
1979         int cpu;
1980
1981         atomic_set(&net->ct.count, 0);
1982
1983         net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
1984         if (!net->ct.pcpu_lists)
1985                 goto err_stat;
1986
1987         for_each_possible_cpu(cpu) {
1988                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1989
1990                 spin_lock_init(&pcpu->lock);
1991                 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
1992                 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
1993         }
1994
1995         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1996         if (!net->ct.stat)
1997                 goto err_pcpu_lists;
1998
1999         ret = nf_conntrack_expect_pernet_init(net);
2000         if (ret < 0)
2001                 goto err_expect;
2002         ret = nf_conntrack_acct_pernet_init(net);
2003         if (ret < 0)
2004                 goto err_acct;
2005         ret = nf_conntrack_tstamp_pernet_init(net);
2006         if (ret < 0)
2007                 goto err_tstamp;
2008         ret = nf_conntrack_ecache_pernet_init(net);
2009         if (ret < 0)
2010                 goto err_ecache;
2011         ret = nf_conntrack_helper_pernet_init(net);
2012         if (ret < 0)
2013                 goto err_helper;
2014         ret = nf_conntrack_proto_pernet_init(net);
2015         if (ret < 0)
2016                 goto err_proto;
2017         return 0;
2018
2019 err_proto:
2020         nf_conntrack_helper_pernet_fini(net);
2021 err_helper:
2022         nf_conntrack_ecache_pernet_fini(net);
2023 err_ecache:
2024         nf_conntrack_tstamp_pernet_fini(net);
2025 err_tstamp:
2026         nf_conntrack_acct_pernet_fini(net);
2027 err_acct:
2028         nf_conntrack_expect_pernet_fini(net);
2029 err_expect:
2030         free_percpu(net->ct.stat);
2031 err_pcpu_lists:
2032         free_percpu(net->ct.pcpu_lists);
2033 err_stat:
2034         return ret;
2035 }