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, u16 zone)
 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, zone ^ 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                                   u16 zone, unsigned int size)
 155 {
 156         return __hash_bucket(hash_conntrack_raw(tuple, zone), size);
 157 }
 158
 159 static inline u_int32_t hash_conntrack(const struct net *net, u16 zone,
 160                                        const struct nf_conntrack_tuple *tuple)
 161 {
 162         return __hash_conntrack(tuple, zone, 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 static void
 291 destroy_conntrack(struct nf_conntrack *nfct)
 292 {
 293         struct nf_conn *ct = (struct nf_conn *)nfct;
 294         struct net *net = nf_ct_net(ct);
 295         struct nf_conntrack_l4proto *l4proto;
 296
 297         pr_debug("destroy_conntrack(%p)\n", ct);
 298         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 299         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 300
 301         rcu_read_lock();
 302         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 303         if (l4proto && l4proto->destroy)
 304                 l4proto->destroy(ct);
 305
 306         rcu_read_unlock();
 307
 308         local_bh_disable();
 309         /* Expectations will have been removed in clean_from_lists,
 310          * except TFTP can create an expectation on the first packet,
 311          * before connection is in the list, so we need to clean here,
 312          * too.
 313          */
 314         nf_ct_remove_expectations(ct);
 315
 316         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 317
 318         NF_CT_STAT_INC(net, delete);
 319         local_bh_enable();
 320
 321         if (ct->master)
 322                 nf_ct_put(ct->master);
 323
 324         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 325         nf_conntrack_free(ct);
 326 }
 327
 328 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 329 {
 330         struct net *net = nf_ct_net(ct);
 331         unsigned int hash, reply_hash;
 332         u16 zone = nf_ct_zone(ct);
 333         unsigned int sequence;
 334
 335         nf_ct_helper_destroy(ct);
 336
 337         local_bh_disable();
 338         do {
 339                 sequence = read_seqcount_begin(&net->ct.generation);
 340                 hash = hash_conntrack(net, zone,
 341                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 342                 reply_hash = hash_conntrack(net, zone,
 343                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 344         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 345
 346         clean_from_lists(ct);
 347         nf_conntrack_double_unlock(hash, reply_hash);
 348
 349         nf_ct_add_to_dying_list(ct);
 350
 351         NF_CT_STAT_INC(net, delete_list);
 352         local_bh_enable();
 353 }
 354
 355 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 356 {
 357         struct nf_conn_tstamp *tstamp;
 358
 359         tstamp = nf_conn_tstamp_find(ct);
 360         if (tstamp && tstamp->stop == 0)
 361                 tstamp->stop = ktime_get_real_ns();
 362
 363         if (nf_ct_is_dying(ct))
 364                 goto delete;
 365
 366         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 367                                     portid, report) < 0) {
 368                 /* destroy event was not delivered */
 369                 nf_ct_delete_from_lists(ct);
 370                 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
 371                 return false;
 372         }
 373
 374         nf_conntrack_ecache_work(nf_ct_net(ct));
 375         set_bit(IPS_DYING_BIT, &ct->status);
 376  delete:
 377         nf_ct_delete_from_lists(ct);
 378         nf_ct_put(ct);
 379         return true;
 380 }
 381 EXPORT_SYMBOL_GPL(nf_ct_delete);
 382
 383 static void death_by_timeout(unsigned long ul_conntrack)
 384 {
 385         nf_ct_delete((struct nf_conn *)ul_conntrack, 0, 0);
 386 }
 387
 388 static inline bool
 389 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 390                         const struct nf_conntrack_tuple *tuple,
 391                         u16 zone)
 392 {
 393         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 394
 395         /* A conntrack can be recreated with the equal tuple,
 396          * so we need to check that the conntrack is confirmed
 397          */
 398         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 399                 nf_ct_zone(ct) == zone &&
 400                 nf_ct_is_confirmed(ct);
 401 }
 402
 403 /*
 404  * Warning :
 405  * - Caller must take a reference on returned object
 406  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 407  */
 408 static struct nf_conntrack_tuple_hash *
 409 ____nf_conntrack_find(struct net *net, u16 zone,
 410                       const struct nf_conntrack_tuple *tuple, u32 hash)
 411 {
 412         struct nf_conntrack_tuple_hash *h;
 413         struct hlist_nulls_node *n;
 414         unsigned int bucket = hash_bucket(hash, net);
 415
 416         /* Disable BHs the entire time since we normally need to disable them
 417          * at least once for the stats anyway.
 418          */
 419         local_bh_disable();
 420 begin:
 421         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
 422                 if (nf_ct_key_equal(h, tuple, zone)) {
 423                         NF_CT_STAT_INC(net, found);
 424                         local_bh_enable();
 425                         return h;
 426                 }
 427                 NF_CT_STAT_INC(net, searched);
 428         }
 429         /*
 430          * if the nulls value we got at the end of this lookup is
 431          * not the expected one, we must restart lookup.
 432          * We probably met an item that was moved to another chain.
 433          */
 434         if (get_nulls_value(n) != bucket) {
 435                 NF_CT_STAT_INC(net, search_restart);
 436                 goto begin;
 437         }
 438         local_bh_enable();
 439
 440         return NULL;
 441 }
 442
 443 /* Find a connection corresponding to a tuple. */
 444 static struct nf_conntrack_tuple_hash *
 445 __nf_conntrack_find_get(struct net *net, u16 zone,
 446                         const struct nf_conntrack_tuple *tuple, u32 hash)
 447 {
 448         struct nf_conntrack_tuple_hash *h;
 449         struct nf_conn *ct;
 450
 451         rcu_read_lock();
 452 begin:
 453         h = ____nf_conntrack_find(net, zone, tuple, hash);
 454         if (h) {
 455                 ct = nf_ct_tuplehash_to_ctrack(h);
 456                 if (unlikely(nf_ct_is_dying(ct) ||
 457                              !atomic_inc_not_zero(&ct->ct_general.use)))
 458                         h = NULL;
 459                 else {
 460                         if (unlikely(!nf_ct_key_equal(h, tuple, zone))) {
 461                                 nf_ct_put(ct);
 462                                 goto begin;
 463                         }
 464                 }
 465         }
 466         rcu_read_unlock();
 467
 468         return h;
 469 }
 470
 471 struct nf_conntrack_tuple_hash *
 472 nf_conntrack_find_get(struct net *net, u16 zone,
 473                       const struct nf_conntrack_tuple *tuple)
 474 {
 475         return __nf_conntrack_find_get(net, zone, tuple,
 476                                        hash_conntrack_raw(tuple, zone));
 477 }
 478 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 479
 480 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 481                                        unsigned int hash,
 482                                        unsigned int reply_hash)
 483 {
 484         struct net *net = nf_ct_net(ct);
 485
 486         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 487                            &net->ct.hash[hash]);
 488         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 489                            &net->ct.hash[reply_hash]);
 490 }
 491
 492 int
 493 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 494 {
 495         struct net *net = nf_ct_net(ct);
 496         unsigned int hash, reply_hash;
 497         struct nf_conntrack_tuple_hash *h;
 498         struct hlist_nulls_node *n;
 499         u16 zone;
 500         unsigned int sequence;
 501
 502         zone = nf_ct_zone(ct);
 503
 504         local_bh_disable();
 505         do {
 506                 sequence = read_seqcount_begin(&net->ct.generation);
 507                 hash = hash_conntrack(net, zone,
 508                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 509                 reply_hash = hash_conntrack(net, zone,
 510                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 511         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 512
 513         /* See if there's one in the list already, including reverse */
 514         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 515                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 516                                       &h->tuple) &&
 517                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 518                         goto out;
 519         hlist_nulls_for_each_entry(h, n, &net->ct.hash[reply_hash], hnnode)
 520                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 521                                       &h->tuple) &&
 522                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 523                         goto out;
 524
 525         add_timer(&ct->timeout);
 526         smp_wmb();
 527         /* The caller holds a reference to this object */
 528         atomic_set(&ct->ct_general.use, 2);
 529         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 530         nf_conntrack_double_unlock(hash, reply_hash);
 531         NF_CT_STAT_INC(net, insert);
 532         local_bh_enable();
 533         return 0;
 534
 535 out:
 536         nf_conntrack_double_unlock(hash, reply_hash);
 537         NF_CT_STAT_INC(net, insert_failed);
 538         local_bh_enable();
 539         return -EEXIST;
 540 }
 541 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 542
 543 /* deletion from this larval template list happens via nf_ct_put() */
 544 void nf_conntrack_tmpl_insert(struct net *net, struct nf_conn *tmpl)
 545 {
 546         struct ct_pcpu *pcpu;
 547
 548         __set_bit(IPS_TEMPLATE_BIT, &tmpl->status);
 549         __set_bit(IPS_CONFIRMED_BIT, &tmpl->status);
 550         nf_conntrack_get(&tmpl->ct_general);
 551
 552         /* add this conntrack to the (per cpu) tmpl list */
 553         local_bh_disable();
 554         tmpl->cpu = smp_processor_id();
 555         pcpu = per_cpu_ptr(nf_ct_net(tmpl)->ct.pcpu_lists, tmpl->cpu);
 556
 557         spin_lock(&pcpu->lock);
 558         /* Overload tuple linked list to put us in template list. */
 559         hlist_nulls_add_head_rcu(&tmpl->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 560                                  &pcpu->tmpl);
 561         spin_unlock_bh(&pcpu->lock);
 562 }
 563 EXPORT_SYMBOL_GPL(nf_conntrack_tmpl_insert);
 564
 565 /* Confirm a connection given skb; places it in hash table */
 566 int
 567 __nf_conntrack_confirm(struct sk_buff *skb)
 568 {
 569         unsigned int hash, reply_hash;
 570         struct nf_conntrack_tuple_hash *h;
 571         struct nf_conn *ct;
 572         struct nf_conn_help *help;
 573         struct nf_conn_tstamp *tstamp;
 574         struct hlist_nulls_node *n;
 575         enum ip_conntrack_info ctinfo;
 576         struct net *net;
 577         u16 zone;
 578         unsigned int sequence;
 579
 580         ct = nf_ct_get(skb, &ctinfo);
 581         net = nf_ct_net(ct);
 582
 583         /* ipt_REJECT uses nf_conntrack_attach to attach related
 584            ICMP/TCP RST packets in other direction.  Actual packet
 585            which created connection will be IP_CT_NEW or for an
 586            expected connection, IP_CT_RELATED. */
 587         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 588                 return NF_ACCEPT;
 589
 590         zone = nf_ct_zone(ct);
 591         local_bh_disable();
 592
 593         do {
 594                 sequence = read_seqcount_begin(&net->ct.generation);
 595                 /* reuse the hash saved before */
 596                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 597                 hash = hash_bucket(hash, net);
 598                 reply_hash = hash_conntrack(net, zone,
 599                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 600
 601         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 602
 603         /* We're not in hash table, and we refuse to set up related
 604          * connections for unconfirmed conns.  But packet copies and
 605          * REJECT will give spurious warnings here.
 606          */
 607         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 608
 609         /* No external references means no one else could have
 610          * confirmed us.
 611          */
 612         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 613         pr_debug("Confirming conntrack %p\n", ct);
 614
 615         /* We have to check the DYING flag after unlink to prevent
 616          * a race against nf_ct_get_next_corpse() possibly called from
 617          * user context, else we insert an already 'dead' hash, blocking
 618          * further use of that particular connection -JM.
 619          */
 620         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 621
 622         if (unlikely(nf_ct_is_dying(ct))) {
 623                 nf_ct_add_to_dying_list(ct);
 624                 nf_conntrack_double_unlock(hash, reply_hash);
 625                 local_bh_enable();
 626                 return NF_ACCEPT;
 627         }
 628
 629         /* See if there's one in the list already, including reverse:
 630            NAT could have grabbed it without realizing, since we're
 631            not in the hash.  If there is, we lost race. */
 632         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 633                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 634                                       &h->tuple) &&
 635                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 636                         goto out;
 637         hlist_nulls_for_each_entry(h, n, &net->ct.hash[reply_hash], hnnode)
 638                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 639                                       &h->tuple) &&
 640                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 641                         goto out;
 642
 643         /* Timer relative to confirmation time, not original
 644            setting time, otherwise we'd get timer wrap in
 645            weird delay cases. */
 646         ct->timeout.expires += jiffies;
 647         add_timer(&ct->timeout);
 648         atomic_inc(&ct->ct_general.use);
 649         ct->status |= IPS_CONFIRMED;
 650
 651         /* set conntrack timestamp, if enabled. */
 652         tstamp = nf_conn_tstamp_find(ct);
 653         if (tstamp) {
 654                 if (skb->tstamp.tv64 == 0)
 655                         __net_timestamp(skb);
 656
 657                 tstamp->start = ktime_to_ns(skb->tstamp);
 658         }
 659         /* Since the lookup is lockless, hash insertion must be done after
 660          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 661          * guarantee that no other CPU can find the conntrack before the above
 662          * stores are visible.
 663          */
 664         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 665         nf_conntrack_double_unlock(hash, reply_hash);
 666         NF_CT_STAT_INC(net, insert);
 667         local_bh_enable();
 668
 669         help = nfct_help(ct);
 670         if (help && help->helper)
 671                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 672
 673         nf_conntrack_event_cache(master_ct(ct) ?
 674                                  IPCT_RELATED : IPCT_NEW, ct);
 675         return NF_ACCEPT;
 676
 677 out:
 678         nf_conntrack_double_unlock(hash, reply_hash);
 679         NF_CT_STAT_INC(net, insert_failed);
 680         local_bh_enable();
 681         return NF_DROP;
 682 }
 683 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 684
 685 /* Returns true if a connection correspondings to the tuple (required
 686    for NAT). */
 687 int
 688 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 689                          const struct nf_conn *ignored_conntrack)
 690 {
 691         struct net *net = nf_ct_net(ignored_conntrack);
 692         struct nf_conntrack_tuple_hash *h;
 693         struct hlist_nulls_node *n;
 694         struct nf_conn *ct;
 695         u16 zone = nf_ct_zone(ignored_conntrack);
 696         unsigned int hash = hash_conntrack(net, zone, tuple);
 697
 698         /* Disable BHs the entire time since we need to disable them at
 699          * least once for the stats anyway.
 700          */
 701         rcu_read_lock_bh();
 702         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 703                 ct = nf_ct_tuplehash_to_ctrack(h);
 704                 if (ct != ignored_conntrack &&
 705                     nf_ct_tuple_equal(tuple, &h->tuple) &&
 706                     nf_ct_zone(ct) == zone) {
 707                         NF_CT_STAT_INC(net, found);
 708                         rcu_read_unlock_bh();
 709                         return 1;
 710                 }
 711                 NF_CT_STAT_INC(net, searched);
 712         }
 713         rcu_read_unlock_bh();
 714
 715         return 0;
 716 }
 717 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 718
 719 #define NF_CT_EVICTION_RANGE    8
 720
 721 /* There's a small race here where we may free a just-assured
 722    connection.  Too bad: we're in trouble anyway. */
 723 static noinline int early_drop(struct net *net, unsigned int _hash)
 724 {
 725         /* Use oldest entry, which is roughly LRU */
 726         struct nf_conntrack_tuple_hash *h;
 727         struct nf_conn *ct = NULL, *tmp;
 728         struct hlist_nulls_node *n;
 729         unsigned int i = 0, cnt = 0;
 730         int dropped = 0;
 731         unsigned int hash, sequence;
 732         spinlock_t *lockp;
 733
 734         local_bh_disable();
 735 restart:
 736         sequence = read_seqcount_begin(&net->ct.generation);
 737         hash = hash_bucket(_hash, net);
 738         for (; i < net->ct.htable_size; i++) {
 739                 lockp = &nf_conntrack_locks[hash % CONNTRACK_LOCKS];
 740                 spin_lock(lockp);
 741                 if (read_seqcount_retry(&net->ct.generation, sequence)) {
 742                         spin_unlock(lockp);
 743                         goto restart;
 744                 }
 745                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 746                                          hnnode) {
 747                         tmp = nf_ct_tuplehash_to_ctrack(h);
 748                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status) &&
 749                             !nf_ct_is_dying(tmp) &&
 750                             atomic_inc_not_zero(&tmp->ct_general.use)) {
 751                                 ct = tmp;
 752                                 break;
 753                         }
 754                         cnt++;
 755                 }
 756
 757                 hash = (hash + 1) % net->ct.htable_size;
 758                 spin_unlock(lockp);
 759
 760                 if (ct || cnt >= NF_CT_EVICTION_RANGE)
 761                         break;
 762
 763         }
 764         local_bh_enable();
 765
 766         if (!ct)
 767                 return dropped;
 768
 769         if (del_timer(&ct->timeout)) {
 770                 if (nf_ct_delete(ct, 0, 0)) {
 771                         dropped = 1;
 772                         NF_CT_STAT_INC_ATOMIC(net, early_drop);
 773                 }
 774         }
 775         nf_ct_put(ct);
 776         return dropped;
 777 }
 778
 779 void init_nf_conntrack_hash_rnd(void)
 780 {
 781         unsigned int rand;
 782
 783         /*
 784          * Why not initialize nf_conntrack_rnd in a "init()" function ?
 785          * Because there isn't enough entropy when system initializing,
 786          * and we initialize it as late as possible.
 787          */
 788         do {
 789                 get_random_bytes(&rand, sizeof(rand));
 790         } while (!rand);
 791         cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
 792 }
 793
 794 static struct nf_conn *
 795 __nf_conntrack_alloc(struct net *net, u16 zone,
 796                      const struct nf_conntrack_tuple *orig,
 797                      const struct nf_conntrack_tuple *repl,
 798                      gfp_t gfp, u32 hash)
 799 {
 800         struct nf_conn *ct;
 801
 802         if (unlikely(!nf_conntrack_hash_rnd)) {
 803                 init_nf_conntrack_hash_rnd();
 804                 /* recompute the hash as nf_conntrack_hash_rnd is initialized */
 805                 hash = hash_conntrack_raw(orig, zone);
 806         }
 807
 808         /* We don't want any race condition at early drop stage */
 809         atomic_inc(&net->ct.count);
 810
 811         if (nf_conntrack_max &&
 812             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
 813                 if (!early_drop(net, hash)) {
 814                         atomic_dec(&net->ct.count);
 815                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
 816                         return ERR_PTR(-ENOMEM);
 817                 }
 818         }
 819
 820         /*
 821          * Do not use kmem_cache_zalloc(), as this cache uses
 822          * SLAB_DESTROY_BY_RCU.
 823          */
 824         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
 825         if (ct == NULL) {
 826                 atomic_dec(&net->ct.count);
 827                 return ERR_PTR(-ENOMEM);
 828         }
 829         /*
 830          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
 831          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
 832          */
 833         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
 834                offsetof(struct nf_conn, proto) -
 835                offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
 836         spin_lock_init(&ct->lock);
 837         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 838         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
 839         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 840         /* save hash for reusing when confirming */
 841         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
 842         /* Don't set timer yet: wait for confirmation */
 843         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 844         write_pnet(&ct->ct_net, net);
 845 #ifdef CONFIG_NF_CONNTRACK_ZONES
 846         if (zone) {
 847                 struct nf_conntrack_zone *nf_ct_zone;
 848
 849                 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC);
 850                 if (!nf_ct_zone)
 851                         goto out_free;
 852                 nf_ct_zone->id = zone;
 853         }
 854 #endif
 855         /* Because we use RCU lookups, we set ct_general.use to zero before
 856          * this is inserted in any list.
 857          */
 858         atomic_set(&ct->ct_general.use, 0);
 859         return ct;
 860
 861 #ifdef CONFIG_NF_CONNTRACK_ZONES
 862 out_free:
 863         atomic_dec(&net->ct.count);
 864         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 865         return ERR_PTR(-ENOMEM);
 866 #endif
 867 }
 868
 869 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 870                                    const struct nf_conntrack_tuple *orig,
 871                                    const struct nf_conntrack_tuple *repl,
 872                                    gfp_t gfp)
 873 {
 874         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
 875 }
 876 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 877
 878 void nf_conntrack_free(struct nf_conn *ct)
 879 {
 880         struct net *net = nf_ct_net(ct);
 881
 882         /* A freed object has refcnt == 0, that's
 883          * the golden rule for SLAB_DESTROY_BY_RCU
 884          */
 885         NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 0);
 886
 887         nf_ct_ext_destroy(ct);
 888         nf_ct_ext_free(ct);
 889         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 890         smp_mb__before_atomic();
 891         atomic_dec(&net->ct.count);
 892 }
 893 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 894
 895
 896 /* Allocate a new conntrack: we return -ENOMEM if classification
 897    failed due to stress.  Otherwise it really is unclassifiable. */
 898 static struct nf_conntrack_tuple_hash *
 899 init_conntrack(struct net *net, struct nf_conn *tmpl,
 900                const struct nf_conntrack_tuple *tuple,
 901                struct nf_conntrack_l3proto *l3proto,
 902                struct nf_conntrack_l4proto *l4proto,
 903                struct sk_buff *skb,
 904                unsigned int dataoff, u32 hash)
 905 {
 906         struct nf_conn *ct;
 907         struct nf_conn_help *help;
 908         struct nf_conntrack_tuple repl_tuple;
 909         struct nf_conntrack_ecache *ecache;
 910         struct nf_conntrack_expect *exp = NULL;
 911         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 912         struct nf_conn_timeout *timeout_ext;
 913         unsigned int *timeouts;
 914
 915         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 916                 pr_debug("Can't invert tuple.\n");
 917                 return NULL;
 918         }
 919
 920         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
 921                                   hash);
 922         if (IS_ERR(ct))
 923                 return (struct nf_conntrack_tuple_hash *)ct;
 924
 925         if (tmpl && nfct_synproxy(tmpl)) {
 926                 nfct_seqadj_ext_add(ct);
 927                 nfct_synproxy_ext_add(ct);
 928         }
 929
 930         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
 931         if (timeout_ext)
 932                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 933         else
 934                 timeouts = l4proto->get_timeouts(net);
 935
 936         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
 937                 nf_conntrack_free(ct);
 938                 pr_debug("init conntrack: can't track with proto module\n");
 939                 return NULL;
 940         }
 941
 942         if (timeout_ext)
 943                 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC);
 944
 945         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 946         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 947         nf_ct_labels_ext_add(ct);
 948
 949         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
 950         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
 951                                  ecache ? ecache->expmask : 0,
 952                              GFP_ATOMIC);
 953
 954         local_bh_disable();
 955         if (net->ct.expect_count) {
 956                 spin_lock(&nf_conntrack_expect_lock);
 957                 exp = nf_ct_find_expectation(net, zone, tuple);
 958                 if (exp) {
 959                         pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 960                                  ct, exp);
 961                         /* Welcome, Mr. Bond.  We've been expecting you... */
 962                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
 963                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
 964                         ct->master = exp->master;
 965                         if (exp->helper) {
 966                                 help = nf_ct_helper_ext_add(ct, exp->helper,
 967                                                             GFP_ATOMIC);
 968                                 if (help)
 969                                         rcu_assign_pointer(help->helper, exp->helper);
 970                         }
 971
 972 #ifdef CONFIG_NF_CONNTRACK_MARK
 973                         ct->mark = exp->master->mark;
 974 #endif
 975 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 976                         ct->secmark = exp->master->secmark;
 977 #endif
 978                         NF_CT_STAT_INC(net, expect_new);
 979                 }
 980                 spin_unlock(&nf_conntrack_expect_lock);
 981         }
 982         if (!exp) {
 983                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
 984                 NF_CT_STAT_INC(net, new);
 985         }
 986
 987         /* Now it is inserted into the unconfirmed list, bump refcount */
 988         nf_conntrack_get(&ct->ct_general);
 989         nf_ct_add_to_unconfirmed_list(ct);
 990
 991         local_bh_enable();
 992
 993         if (exp) {
 994                 if (exp->expectfn)
 995                         exp->expectfn(ct, exp);
 996                 nf_ct_expect_put(exp);
 997         }
 998
 999         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1000 }
1001
1002 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
1003 static inline struct nf_conn *
1004 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
1005                   struct sk_buff *skb,
1006                   unsigned int dataoff,
1007                   u_int16_t l3num,
1008                   u_int8_t protonum,
1009                   struct nf_conntrack_l3proto *l3proto,
1010                   struct nf_conntrack_l4proto *l4proto,
1011                   int *set_reply,
1012                   enum ip_conntrack_info *ctinfo)
1013 {
1014         struct nf_conntrack_tuple tuple;
1015         struct nf_conntrack_tuple_hash *h;
1016         struct nf_conn *ct;
1017         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
1018         u32 hash;
1019
1020         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1021                              dataoff, l3num, protonum, &tuple, l3proto,
1022                              l4proto)) {
1023                 pr_debug("resolve_normal_ct: Can't get tuple\n");
1024                 return NULL;
1025         }
1026
1027         /* look for tuple match */
1028         hash = hash_conntrack_raw(&tuple, zone);
1029         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
1030         if (!h) {
1031                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
1032                                    skb, dataoff, hash);
1033                 if (!h)
1034                         return NULL;
1035                 if (IS_ERR(h))
1036                         return (void *)h;
1037         }
1038         ct = nf_ct_tuplehash_to_ctrack(h);
1039
1040         /* It exists; we have (non-exclusive) reference. */
1041         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1042                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
1043                 /* Please set reply bit if this packet OK */
1044                 *set_reply = 1;
1045         } else {
1046                 /* Once we've had two way comms, always ESTABLISHED. */
1047                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1048                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
1049                         *ctinfo = IP_CT_ESTABLISHED;
1050                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1051                         pr_debug("nf_conntrack_in: related packet for %p\n",
1052                                  ct);
1053                         *ctinfo = IP_CT_RELATED;
1054                 } else {
1055                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
1056                         *ctinfo = IP_CT_NEW;
1057                 }
1058                 *set_reply = 0;
1059         }
1060         skb->nfct = &ct->ct_general;
1061         skb->nfctinfo = *ctinfo;
1062         return ct;
1063 }
1064
1065 unsigned int
1066 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
1067                 struct sk_buff *skb)
1068 {
1069         struct nf_conn *ct, *tmpl = NULL;
1070         enum ip_conntrack_info ctinfo;
1071         struct nf_conntrack_l3proto *l3proto;
1072         struct nf_conntrack_l4proto *l4proto;
1073         unsigned int *timeouts;
1074         unsigned int dataoff;
1075         u_int8_t protonum;
1076         int set_reply = 0;
1077         int ret;
1078
1079         if (skb->nfct) {
1080                 /* Previously seen (loopback or untracked)?  Ignore. */
1081                 tmpl = (struct nf_conn *)skb->nfct;
1082                 if (!nf_ct_is_template(tmpl)) {
1083                         NF_CT_STAT_INC_ATOMIC(net, ignore);
1084                         return NF_ACCEPT;
1085                 }
1086                 skb->nfct = NULL;
1087         }
1088
1089         /* rcu_read_lock()ed by nf_hook_slow */
1090         l3proto = __nf_ct_l3proto_find(pf);
1091         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
1092                                    &dataoff, &protonum);
1093         if (ret <= 0) {
1094                 pr_debug("not prepared to track yet or error occurred\n");
1095                 NF_CT_STAT_INC_ATOMIC(net, error);
1096                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1097                 ret = -ret;
1098                 goto out;
1099         }
1100
1101         l4proto = __nf_ct_l4proto_find(pf, protonum);
1102
1103         /* It may be an special packet, error, unclean...
1104          * inverse of the return code tells to the netfilter
1105          * core what to do with the packet. */
1106         if (l4proto->error != NULL) {
1107                 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
1108                                      pf, hooknum);
1109                 if (ret <= 0) {
1110                         NF_CT_STAT_INC_ATOMIC(net, error);
1111                         NF_CT_STAT_INC_ATOMIC(net, invalid);
1112                         ret = -ret;
1113                         goto out;
1114                 }
1115                 /* ICMP[v6] protocol trackers may assign one conntrack. */
1116                 if (skb->nfct)
1117                         goto out;
1118         }
1119
1120         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
1121                                l3proto, l4proto, &set_reply, &ctinfo);
1122         if (!ct) {
1123                 /* Not valid part of a connection */
1124                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1125                 ret = NF_ACCEPT;
1126                 goto out;
1127         }
1128
1129         if (IS_ERR(ct)) {
1130                 /* Too stressed to deal. */
1131                 NF_CT_STAT_INC_ATOMIC(net, drop);
1132                 ret = NF_DROP;
1133                 goto out;
1134         }
1135
1136         NF_CT_ASSERT(skb->nfct);
1137
1138         /* Decide what timeout policy we want to apply to this flow. */
1139         timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1140
1141         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1142         if (ret <= 0) {
1143                 /* Invalid: inverse of the return code tells
1144                  * the netfilter core what to do */
1145                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1146                 nf_conntrack_put(skb->nfct);
1147                 skb->nfct = NULL;
1148                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1149                 if (ret == -NF_DROP)
1150                         NF_CT_STAT_INC_ATOMIC(net, drop);
1151                 ret = -ret;
1152                 goto out;
1153         }
1154
1155         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1156                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1157 out:
1158         if (tmpl) {
1159                 /* Special case: we have to repeat this hook, assign the
1160                  * template again to this packet. We assume that this packet
1161                  * has no conntrack assigned. This is used by nf_ct_tcp. */
1162                 if (ret == NF_REPEAT)
1163                         skb->nfct = (struct nf_conntrack *)tmpl;
1164                 else
1165                         nf_ct_put(tmpl);
1166         }
1167
1168         return ret;
1169 }
1170 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1171
1172 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1173                           const struct nf_conntrack_tuple *orig)
1174 {
1175         bool ret;
1176
1177         rcu_read_lock();
1178         ret = nf_ct_invert_tuple(inverse, orig,
1179                                  __nf_ct_l3proto_find(orig->src.l3num),
1180                                  __nf_ct_l4proto_find(orig->src.l3num,
1181                                                       orig->dst.protonum));
1182         rcu_read_unlock();
1183         return ret;
1184 }
1185 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1186
1187 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1188    implicitly racy: see __nf_conntrack_confirm */
1189 void nf_conntrack_alter_reply(struct nf_conn *ct,
1190                               const struct nf_conntrack_tuple *newreply)
1191 {
1192         struct nf_conn_help *help = nfct_help(ct);
1193
1194         /* Should be unconfirmed, so not in hash table yet */
1195         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1196
1197         pr_debug("Altering reply tuple of %p to ", ct);
1198         nf_ct_dump_tuple(newreply);
1199
1200         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1201         if (ct->master || (help && !hlist_empty(&help->expectations)))
1202                 return;
1203
1204         rcu_read_lock();
1205         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1206         rcu_read_unlock();
1207 }
1208 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1209
1210 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1211 void __nf_ct_refresh_acct(struct nf_conn *ct,
1212                           enum ip_conntrack_info ctinfo,
1213                           const struct sk_buff *skb,
1214                           unsigned long extra_jiffies,
1215                           int do_acct)
1216 {
1217         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1218         NF_CT_ASSERT(skb);
1219
1220         /* Only update if this is not a fixed timeout */
1221         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1222                 goto acct;
1223
1224         /* If not in hash table, timer will not be active yet */
1225         if (!nf_ct_is_confirmed(ct)) {
1226                 ct->timeout.expires = extra_jiffies;
1227         } else {
1228                 unsigned long newtime = jiffies + extra_jiffies;
1229
1230                 /* Only update the timeout if the new timeout is at least
1231                    HZ jiffies from the old timeout. Need del_timer for race
1232                    avoidance (may already be dying). */
1233                 if (newtime - ct->timeout.expires >= HZ)
1234                         mod_timer_pending(&ct->timeout, newtime);
1235         }
1236
1237 acct:
1238         if (do_acct) {
1239                 struct nf_conn_acct *acct;
1240
1241                 acct = nf_conn_acct_find(ct);
1242                 if (acct) {
1243                         struct nf_conn_counter *counter = acct->counter;
1244
1245                         atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
1246                         atomic64_add(skb->len, &counter[CTINFO2DIR(ctinfo)].bytes);
1247                 }
1248         }
1249 }
1250 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1251
1252 bool __nf_ct_kill_acct(struct nf_conn *ct,
1253                        enum ip_conntrack_info ctinfo,
1254                        const struct sk_buff *skb,
1255                        int do_acct)
1256 {
1257         if (do_acct) {
1258                 struct nf_conn_acct *acct;
1259
1260                 acct = nf_conn_acct_find(ct);
1261                 if (acct) {
1262                         struct nf_conn_counter *counter = acct->counter;
1263
1264                         atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
1265                         atomic64_add(skb->len - skb_network_offset(skb),
1266                                      &counter[CTINFO2DIR(ctinfo)].bytes);
1267                 }
1268         }
1269
1270         if (del_timer(&ct->timeout)) {
1271                 ct->timeout.function((unsigned long)ct);
1272                 return true;
1273         }
1274         return false;
1275 }
1276 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1277
1278 #ifdef CONFIG_NF_CONNTRACK_ZONES
1279 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1280         .len    = sizeof(struct nf_conntrack_zone),
1281         .align  = __alignof__(struct nf_conntrack_zone),
1282         .id     = NF_CT_EXT_ZONE,
1283 };
1284 #endif
1285
1286 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1287
1288 #include <linux/netfilter/nfnetlink.h>
1289 #include <linux/netfilter/nfnetlink_conntrack.h>
1290 #include <linux/mutex.h>
1291
1292 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1293  * in ip_conntrack_core, since we don't want the protocols to autoload
1294  * or depend on ctnetlink */
1295 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1296                                const struct nf_conntrack_tuple *tuple)
1297 {
1298         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1299             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1300                 goto nla_put_failure;
1301         return 0;
1302
1303 nla_put_failure:
1304         return -1;
1305 }
1306 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1307
1308 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1309         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1310         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1311 };
1312 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1313
1314 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1315                                struct nf_conntrack_tuple *t)
1316 {
1317         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1318                 return -EINVAL;
1319
1320         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1321         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1322
1323         return 0;
1324 }
1325 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1326
1327 int nf_ct_port_nlattr_tuple_size(void)
1328 {
1329         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1330 }
1331 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1332 #endif
1333
1334 /* Used by ipt_REJECT and ip6t_REJECT. */
1335 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1336 {
1337         struct nf_conn *ct;
1338         enum ip_conntrack_info ctinfo;
1339
1340         /* This ICMP is in reverse direction to the packet which caused it */
1341         ct = nf_ct_get(skb, &ctinfo);
1342         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1343                 ctinfo = IP_CT_RELATED_REPLY;
1344         else
1345                 ctinfo = IP_CT_RELATED;
1346
1347         /* Attach to new skbuff, and increment count */
1348         nskb->nfct = &ct->ct_general;
1349         nskb->nfctinfo = ctinfo;
1350         nf_conntrack_get(nskb->nfct);
1351 }
1352
1353 /* Bring out ya dead! */
1354 static struct nf_conn *
1355 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1356                 void *data, unsigned int *bucket)
1357 {
1358         struct nf_conntrack_tuple_hash *h;
1359         struct nf_conn *ct;
1360         struct hlist_nulls_node *n;
1361         int cpu;
1362         spinlock_t *lockp;
1363
1364         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1365                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
1366                 local_bh_disable();
1367                 spin_lock(lockp);
1368                 if (*bucket < net->ct.htable_size) {
1369                         hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1370                                 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
1371                                         continue;
1372                                 ct = nf_ct_tuplehash_to_ctrack(h);
1373                                 if (iter(ct, data))
1374                                         goto found;
1375                         }
1376                 }
1377                 spin_unlock(lockp);
1378                 local_bh_enable();
1379         }
1380
1381         for_each_possible_cpu(cpu) {
1382                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1383
1384                 spin_lock_bh(&pcpu->lock);
1385                 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
1386                         ct = nf_ct_tuplehash_to_ctrack(h);
1387                         if (iter(ct, data))
1388                                 set_bit(IPS_DYING_BIT, &ct->status);
1389                 }
1390                 spin_unlock_bh(&pcpu->lock);
1391         }
1392         return NULL;
1393 found:
1394         atomic_inc(&ct->ct_general.use);
1395         spin_unlock(lockp);
1396         local_bh_enable();
1397         return ct;
1398 }
1399
1400 void nf_ct_iterate_cleanup(struct net *net,
1401                            int (*iter)(struct nf_conn *i, void *data),
1402                            void *data, u32 portid, int report)
1403 {
1404         struct nf_conn *ct;
1405         unsigned int bucket = 0;
1406
1407         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1408                 /* Time to push up daises... */
1409                 if (del_timer(&ct->timeout))
1410                         nf_ct_delete(ct, portid, report);
1411
1412                 /* ... else the timer will get him soon. */
1413
1414                 nf_ct_put(ct);
1415         }
1416 }
1417 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1418
1419 static int kill_all(struct nf_conn *i, void *data)
1420 {
1421         return 1;
1422 }
1423
1424 void nf_ct_free_hashtable(void *hash, unsigned int size)
1425 {
1426         if (is_vmalloc_addr(hash))
1427                 vfree(hash);
1428         else
1429                 free_pages((unsigned long)hash,
1430                            get_order(sizeof(struct hlist_head) * size));
1431 }
1432 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1433
1434 void nf_conntrack_flush_report(struct net *net, u32 portid, int report)
1435 {
1436         nf_ct_iterate_cleanup(net, kill_all, NULL, portid, report);
1437 }
1438 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1439
1440 static int untrack_refs(void)
1441 {
1442         int cnt = 0, cpu;
1443
1444         for_each_possible_cpu(cpu) {
1445                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1446
1447                 cnt += atomic_read(&ct->ct_general.use) - 1;
1448         }
1449         return cnt;
1450 }
1451
1452 void nf_conntrack_cleanup_start(void)
1453 {
1454         RCU_INIT_POINTER(ip_ct_attach, NULL);
1455 }
1456
1457 void nf_conntrack_cleanup_end(void)
1458 {
1459         RCU_INIT_POINTER(nf_ct_destroy, NULL);
1460         while (untrack_refs() > 0)
1461                 schedule();
1462
1463 #ifdef CONFIG_NF_CONNTRACK_ZONES
1464         nf_ct_extend_unregister(&nf_ct_zone_extend);
1465 #endif
1466         nf_conntrack_proto_fini();
1467         nf_conntrack_seqadj_fini();
1468         nf_conntrack_labels_fini();
1469         nf_conntrack_helper_fini();
1470         nf_conntrack_timeout_fini();
1471         nf_conntrack_ecache_fini();
1472         nf_conntrack_tstamp_fini();
1473         nf_conntrack_acct_fini();
1474         nf_conntrack_expect_fini();
1475 }
1476
1477 /*
1478  * Mishearing the voices in his head, our hero wonders how he's
1479  * supposed to kill the mall.
1480  */
1481 void nf_conntrack_cleanup_net(struct net *net)
1482 {
1483         LIST_HEAD(single);
1484
1485         list_add(&net->exit_list, &single);
1486         nf_conntrack_cleanup_net_list(&single);
1487 }
1488
1489 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
1490 {
1491         int busy;
1492         struct net *net;
1493
1494         /*
1495          * This makes sure all current packets have passed through
1496          *  netfilter framework.  Roll on, two-stage module
1497          *  delete...
1498          */
1499         synchronize_net();
1500 i_see_dead_people:
1501         busy = 0;
1502         list_for_each_entry(net, net_exit_list, exit_list) {
1503                 nf_ct_iterate_cleanup(net, kill_all, NULL, 0, 0);
1504                 if (atomic_read(&net->ct.count) != 0)
1505                         busy = 1;
1506         }
1507         if (busy) {
1508                 schedule();
1509                 goto i_see_dead_people;
1510         }
1511
1512         list_for_each_entry(net, net_exit_list, exit_list) {
1513                 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1514                 nf_conntrack_proto_pernet_fini(net);
1515                 nf_conntrack_helper_pernet_fini(net);
1516                 nf_conntrack_ecache_pernet_fini(net);
1517                 nf_conntrack_tstamp_pernet_fini(net);
1518                 nf_conntrack_acct_pernet_fini(net);
1519                 nf_conntrack_expect_pernet_fini(net);
1520                 kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1521                 kfree(net->ct.slabname);
1522                 free_percpu(net->ct.stat);
1523                 free_percpu(net->ct.pcpu_lists);
1524         }
1525 }
1526
1527 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1528 {
1529         struct hlist_nulls_head *hash;
1530         unsigned int nr_slots, i;
1531         size_t sz;
1532
1533         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1534         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1535         sz = nr_slots * sizeof(struct hlist_nulls_head);
1536         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1537                                         get_order(sz));
1538         if (!hash) {
1539                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1540                 hash = vzalloc(sz);
1541         }
1542
1543         if (hash && nulls)
1544                 for (i = 0; i < nr_slots; i++)
1545                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1546
1547         return hash;
1548 }
1549 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1550
1551 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1552 {
1553         int i, bucket, rc;
1554         unsigned int hashsize, old_size;
1555         struct hlist_nulls_head *hash, *old_hash;
1556         struct nf_conntrack_tuple_hash *h;
1557         struct nf_conn *ct;
1558
1559         if (current->nsproxy->net_ns != &init_net)
1560                 return -EOPNOTSUPP;
1561
1562         /* On boot, we can set this without any fancy locking. */
1563         if (!nf_conntrack_htable_size)
1564                 return param_set_uint(val, kp);
1565
1566         rc = kstrtouint(val, 0, &hashsize);
1567         if (rc)
1568                 return rc;
1569         if (!hashsize)
1570                 return -EINVAL;
1571
1572         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1573         if (!hash)
1574                 return -ENOMEM;
1575
1576         local_bh_disable();
1577         nf_conntrack_all_lock();
1578         write_seqcount_begin(&init_net.ct.generation);
1579
1580         /* Lookups in the old hash might happen in parallel, which means we
1581          * might get false negatives during connection lookup. New connections
1582          * created because of a false negative won't make it into the hash
1583          * though since that required taking the locks.
1584          */
1585
1586         for (i = 0; i < init_net.ct.htable_size; i++) {
1587                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1588                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1589                                         struct nf_conntrack_tuple_hash, hnnode);
1590                         ct = nf_ct_tuplehash_to_ctrack(h);
1591                         hlist_nulls_del_rcu(&h->hnnode);
1592                         bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct),
1593                                                   hashsize);
1594                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1595                 }
1596         }
1597         old_size = init_net.ct.htable_size;
1598         old_hash = init_net.ct.hash;
1599
1600         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1601         init_net.ct.hash = hash;
1602
1603         write_seqcount_end(&init_net.ct.generation);
1604         nf_conntrack_all_unlock();
1605         local_bh_enable();
1606
1607         nf_ct_free_hashtable(old_hash, old_size);
1608         return 0;
1609 }
1610 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1611
1612 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1613                   &nf_conntrack_htable_size, 0600);
1614
1615 void nf_ct_untracked_status_or(unsigned long bits)
1616 {
1617         int cpu;
1618
1619         for_each_possible_cpu(cpu)
1620                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1621 }
1622 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1623
1624 int nf_conntrack_init_start(void)
1625 {
1626         int max_factor = 8;
1627         int i, ret, cpu;
1628
1629         for (i = 0; i < CONNTRACK_LOCKS; i++)
1630                 spin_lock_init(&nf_conntrack_locks[i]);
1631
1632         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1633          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1634         if (!nf_conntrack_htable_size) {
1635                 nf_conntrack_htable_size
1636                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1637                            / sizeof(struct hlist_head));
1638                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1639                         nf_conntrack_htable_size = 16384;
1640                 if (nf_conntrack_htable_size < 32)
1641                         nf_conntrack_htable_size = 32;
1642
1643                 /* Use a max. factor of four by default to get the same max as
1644                  * with the old struct list_heads. When a table size is given
1645                  * we use the old value of 8 to avoid reducing the max.
1646                  * entries. */
1647                 max_factor = 4;
1648         }
1649         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1650
1651         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1652                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1653                nf_conntrack_max);
1654
1655         ret = nf_conntrack_expect_init();
1656         if (ret < 0)
1657                 goto err_expect;
1658
1659         ret = nf_conntrack_acct_init();
1660         if (ret < 0)
1661                 goto err_acct;
1662
1663         ret = nf_conntrack_tstamp_init();
1664         if (ret < 0)
1665                 goto err_tstamp;
1666
1667         ret = nf_conntrack_ecache_init();
1668         if (ret < 0)
1669                 goto err_ecache;
1670
1671         ret = nf_conntrack_timeout_init();
1672         if (ret < 0)
1673                 goto err_timeout;
1674
1675         ret = nf_conntrack_helper_init();
1676         if (ret < 0)
1677                 goto err_helper;
1678
1679         ret = nf_conntrack_labels_init();
1680         if (ret < 0)
1681                 goto err_labels;
1682
1683         ret = nf_conntrack_seqadj_init();
1684         if (ret < 0)
1685                 goto err_seqadj;
1686
1687 #ifdef CONFIG_NF_CONNTRACK_ZONES
1688         ret = nf_ct_extend_register(&nf_ct_zone_extend);
1689         if (ret < 0)
1690                 goto err_extend;
1691 #endif
1692         ret = nf_conntrack_proto_init();
1693         if (ret < 0)
1694                 goto err_proto;
1695
1696         /* Set up fake conntrack: to never be deleted, not in any hashes */
1697         for_each_possible_cpu(cpu) {
1698                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1699                 write_pnet(&ct->ct_net, &init_net);
1700                 atomic_set(&ct->ct_general.use, 1);
1701         }
1702         /*  - and look it like as a confirmed connection */
1703         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1704         return 0;
1705
1706 err_proto:
1707 #ifdef CONFIG_NF_CONNTRACK_ZONES
1708         nf_ct_extend_unregister(&nf_ct_zone_extend);
1709 err_extend:
1710 #endif
1711         nf_conntrack_seqadj_fini();
1712 err_seqadj:
1713         nf_conntrack_labels_fini();
1714 err_labels:
1715         nf_conntrack_helper_fini();
1716 err_helper:
1717         nf_conntrack_timeout_fini();
1718 err_timeout:
1719         nf_conntrack_ecache_fini();
1720 err_ecache:
1721         nf_conntrack_tstamp_fini();
1722 err_tstamp:
1723         nf_conntrack_acct_fini();
1724 err_acct:
1725         nf_conntrack_expect_fini();
1726 err_expect:
1727         return ret;
1728 }
1729
1730 void nf_conntrack_init_end(void)
1731 {
1732         /* For use by REJECT target */
1733         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1734         RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1735 }
1736
1737 /*
1738  * We need to use special "null" values, not used in hash table
1739  */
1740 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1741 #define DYING_NULLS_VAL         ((1<<30)+1)
1742 #define TEMPLATE_NULLS_VAL      ((1<<30)+2)
1743
1744 int nf_conntrack_init_net(struct net *net)
1745 {
1746         int ret = -ENOMEM;
1747         int cpu;
1748
1749         atomic_set(&net->ct.count, 0);
1750         seqcount_init(&net->ct.generation);
1751
1752         net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
1753         if (!net->ct.pcpu_lists)
1754                 goto err_stat;
1755
1756         for_each_possible_cpu(cpu) {
1757                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
1758
1759                 spin_lock_init(&pcpu->lock);
1760                 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
1761                 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
1762                 INIT_HLIST_NULLS_HEAD(&pcpu->tmpl, TEMPLATE_NULLS_VAL);
1763         }
1764
1765         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1766         if (!net->ct.stat)
1767                 goto err_pcpu_lists;
1768
1769         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1770         if (!net->ct.slabname)
1771                 goto err_slabname;
1772
1773         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1774                                                         sizeof(struct nf_conn), 0,
1775                                                         SLAB_DESTROY_BY_RCU, NULL);
1776         if (!net->ct.nf_conntrack_cachep) {
1777                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1778                 goto err_cache;
1779         }
1780
1781         net->ct.htable_size = nf_conntrack_htable_size;
1782         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1783         if (!net->ct.hash) {
1784                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1785                 goto err_hash;
1786         }
1787         ret = nf_conntrack_expect_pernet_init(net);
1788         if (ret < 0)
1789                 goto err_expect;
1790         ret = nf_conntrack_acct_pernet_init(net);
1791         if (ret < 0)
1792                 goto err_acct;
1793         ret = nf_conntrack_tstamp_pernet_init(net);
1794         if (ret < 0)
1795                 goto err_tstamp;
1796         ret = nf_conntrack_ecache_pernet_init(net);
1797         if (ret < 0)
1798                 goto err_ecache;
1799         ret = nf_conntrack_helper_pernet_init(net);
1800         if (ret < 0)
1801                 goto err_helper;
1802         ret = nf_conntrack_proto_pernet_init(net);
1803         if (ret < 0)
1804                 goto err_proto;
1805         return 0;
1806
1807 err_proto:
1808         nf_conntrack_helper_pernet_fini(net);
1809 err_helper:
1810         nf_conntrack_ecache_pernet_fini(net);
1811 err_ecache:
1812         nf_conntrack_tstamp_pernet_fini(net);
1813 err_tstamp:
1814         nf_conntrack_acct_pernet_fini(net);
1815 err_acct:
1816         nf_conntrack_expect_pernet_fini(net);
1817 err_expect:
1818         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1819 err_hash:
1820         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1821 err_cache:
1822         kfree(net->ct.slabname);
1823 err_slabname:
1824         free_percpu(net->ct.stat);
1825 err_pcpu_lists:
1826         free_percpu(net->ct.pcpu_lists);
1827 err_stat:
1828         return ret;
1829 }