net/netfilter/nf_conntrack_core.c

   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/types.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/module.h>
  17 #include <linux/sched.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/stddef.h>
  22 #include <linux/slab.h>
  23 #include <linux/random.h>
  24 #include <linux/jhash.h>
  25 #include <linux/err.h>
  26 #include <linux/percpu.h>
  27 #include <linux/moduleparam.h>
  28 #include <linux/notifier.h>
  29 #include <linux/kernel.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/socket.h>
  32 #include <linux/mm.h>
  33 #include <linux/nsproxy.h>
  34 #include <linux/rculist_nulls.h>
  35
  36 #include <net/netfilter/nf_conntrack.h>
  37 #include <net/netfilter/nf_conntrack_l3proto.h>
  38 #include <net/netfilter/nf_conntrack_l4proto.h>
  39 #include <net/netfilter/nf_conntrack_expect.h>
  40 #include <net/netfilter/nf_conntrack_helper.h>
  41 #include <net/netfilter/nf_conntrack_core.h>
  42 #include <net/netfilter/nf_conntrack_extend.h>
  43 #include <net/netfilter/nf_conntrack_acct.h>
  44 #include <net/netfilter/nf_conntrack_ecache.h>
  45 #include <net/netfilter/nf_conntrack_zones.h>
  46 #include <net/netfilter/nf_conntrack_timestamp.h>
  47 #include <net/netfilter/nf_conntrack_timeout.h>
  48 #include <net/netfilter/nf_nat.h>
  49 #include <net/netfilter/nf_nat_core.h>
  50
  51 #define NF_CONNTRACK_VERSION    "0.5.0"
  52
  53 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
  54                                       enum nf_nat_manip_type manip,
  55                                       const struct nlattr *attr) __read_mostly;
  56 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
  57
  58 DEFINE_SPINLOCK(nf_conntrack_lock);
  59 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  60
  61 unsigned int nf_conntrack_htable_size __read_mostly;
  62 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  63
  64 unsigned int nf_conntrack_max __read_mostly;
  65 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  66
  67 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
  68 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
  69
  70 unsigned int nf_conntrack_hash_rnd __read_mostly;
  71 EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd);
  72
  73 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone)
  74 {
  75         unsigned int n;
  76
  77         /* The direction must be ignored, so we hash everything up to the
  78          * destination ports (which is a multiple of 4) and treat the last
  79          * three bytes manually.
  80          */
  81         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
  82         return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^
  83                       (((__force __u16)tuple->dst.u.all << 16) |
  84                       tuple->dst.protonum));
  85 }
  86
  87 static u32 __hash_bucket(u32 hash, unsigned int size)
  88 {
  89         return ((u64)hash * size) >> 32;
  90 }
  91
  92 static u32 hash_bucket(u32 hash, const struct net *net)
  93 {
  94         return __hash_bucket(hash, net->ct.htable_size);
  95 }
  96
  97 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
  98                                   u16 zone, unsigned int size)
  99 {
 100         return __hash_bucket(hash_conntrack_raw(tuple, zone), size);
 101 }
 102
 103 static inline u_int32_t hash_conntrack(const struct net *net, u16 zone,
 104                                        const struct nf_conntrack_tuple *tuple)
 105 {
 106         return __hash_conntrack(tuple, zone, net->ct.htable_size);
 107 }
 108
 109 bool
 110 nf_ct_get_tuple(const struct sk_buff *skb,
 111                 unsigned int nhoff,
 112                 unsigned int dataoff,
 113                 u_int16_t l3num,
 114                 u_int8_t protonum,
 115                 struct nf_conntrack_tuple *tuple,
 116                 const struct nf_conntrack_l3proto *l3proto,
 117                 const struct nf_conntrack_l4proto *l4proto)
 118 {
 119         memset(tuple, 0, sizeof(*tuple));
 120
 121         tuple->src.l3num = l3num;
 122         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 123                 return false;
 124
 125         tuple->dst.protonum = protonum;
 126         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 127
 128         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 129 }
 130 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 131
 132 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 133                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
 134 {
 135         struct nf_conntrack_l3proto *l3proto;
 136         struct nf_conntrack_l4proto *l4proto;
 137         unsigned int protoff;
 138         u_int8_t protonum;
 139         int ret;
 140
 141         rcu_read_lock();
 142
 143         l3proto = __nf_ct_l3proto_find(l3num);
 144         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 145         if (ret != NF_ACCEPT) {
 146                 rcu_read_unlock();
 147                 return false;
 148         }
 149
 150         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 151
 152         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 153                               l3proto, l4proto);
 154
 155         rcu_read_unlock();
 156         return ret;
 157 }
 158 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 159
 160 bool
 161 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 162                    const struct nf_conntrack_tuple *orig,
 163                    const struct nf_conntrack_l3proto *l3proto,
 164                    const struct nf_conntrack_l4proto *l4proto)
 165 {
 166         memset(inverse, 0, sizeof(*inverse));
 167
 168         inverse->src.l3num = orig->src.l3num;
 169         if (l3proto->invert_tuple(inverse, orig) == 0)
 170                 return false;
 171
 172         inverse->dst.dir = !orig->dst.dir;
 173
 174         inverse->dst.protonum = orig->dst.protonum;
 175         return l4proto->invert_tuple(inverse, orig);
 176 }
 177 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 178
 179 static void
 180 clean_from_lists(struct nf_conn *ct)
 181 {
 182         pr_debug("clean_from_lists(%p)\n", ct);
 183         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 184         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 185
 186         /* Destroy all pending expectations */
 187         nf_ct_remove_expectations(ct);
 188 }
 189
 190 static void
 191 destroy_conntrack(struct nf_conntrack *nfct)
 192 {
 193         struct nf_conn *ct = (struct nf_conn *)nfct;
 194         struct net *net = nf_ct_net(ct);
 195         struct nf_conntrack_l4proto *l4proto;
 196
 197         pr_debug("destroy_conntrack(%p)\n", ct);
 198         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 199         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 200
 201         /* To make sure we don't get any weird locking issues here:
 202          * destroy_conntrack() MUST NOT be called with a write lock
 203          * to nf_conntrack_lock!!! -HW */
 204         rcu_read_lock();
 205         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 206         if (l4proto && l4proto->destroy)
 207                 l4proto->destroy(ct);
 208
 209         rcu_read_unlock();
 210
 211         spin_lock_bh(&nf_conntrack_lock);
 212         /* Expectations will have been removed in clean_from_lists,
 213          * except TFTP can create an expectation on the first packet,
 214          * before connection is in the list, so we need to clean here,
 215          * too. */
 216         nf_ct_remove_expectations(ct);
 217
 218         /* We overload first tuple to link into unconfirmed list. */
 219         if (!nf_ct_is_confirmed(ct)) {
 220                 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 221                 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 222         }
 223
 224         NF_CT_STAT_INC(net, delete);
 225         spin_unlock_bh(&nf_conntrack_lock);
 226
 227         if (ct->master)
 228                 nf_ct_put(ct->master);
 229
 230         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 231         nf_conntrack_free(ct);
 232 }
 233
 234 void nf_ct_delete_from_lists(struct nf_conn *ct)
 235 {
 236         struct net *net = nf_ct_net(ct);
 237
 238         nf_ct_helper_destroy(ct);
 239         spin_lock_bh(&nf_conntrack_lock);
 240         /* Inside lock so preempt is disabled on module removal path.
 241          * Otherwise we can get spurious warnings. */
 242         NF_CT_STAT_INC(net, delete_list);
 243         clean_from_lists(ct);
 244         spin_unlock_bh(&nf_conntrack_lock);
 245 }
 246 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
 247
 248 static void death_by_event(unsigned long ul_conntrack)
 249 {
 250         struct nf_conn *ct = (void *)ul_conntrack;
 251         struct net *net = nf_ct_net(ct);
 252
 253         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
 254                 /* bad luck, let's retry again */
 255                 ct->timeout.expires = jiffies +
 256                         (random32() % net->ct.sysctl_events_retry_timeout);
 257                 add_timer(&ct->timeout);
 258                 return;
 259         }
 260         /* we've got the event delivered, now it's dying */
 261         set_bit(IPS_DYING_BIT, &ct->status);
 262         spin_lock(&nf_conntrack_lock);
 263         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 264         spin_unlock(&nf_conntrack_lock);
 265         nf_ct_put(ct);
 266 }
 267
 268 void nf_ct_insert_dying_list(struct nf_conn *ct)
 269 {
 270         struct net *net = nf_ct_net(ct);
 271
 272         /* add this conntrack to the dying list */
 273         spin_lock_bh(&nf_conntrack_lock);
 274         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 275                              &net->ct.dying);
 276         spin_unlock_bh(&nf_conntrack_lock);
 277         /* set a new timer to retry event delivery */
 278         setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
 279         ct->timeout.expires = jiffies +
 280                 (random32() % net->ct.sysctl_events_retry_timeout);
 281         add_timer(&ct->timeout);
 282 }
 283 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
 284
 285 static void death_by_timeout(unsigned long ul_conntrack)
 286 {
 287         struct nf_conn *ct = (void *)ul_conntrack;
 288         struct nf_conn_tstamp *tstamp;
 289
 290         tstamp = nf_conn_tstamp_find(ct);
 291         if (tstamp && tstamp->stop == 0)
 292                 tstamp->stop = ktime_to_ns(ktime_get_real());
 293
 294         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
 295             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
 296                 /* destroy event was not delivered */
 297                 nf_ct_delete_from_lists(ct);
 298                 nf_ct_insert_dying_list(ct);
 299                 return;
 300         }
 301         set_bit(IPS_DYING_BIT, &ct->status);
 302         nf_ct_delete_from_lists(ct);
 303         nf_ct_put(ct);
 304 }
 305
 306 /*
 307  * Warning :
 308  * - Caller must take a reference on returned object
 309  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 310  * OR
 311  * - Caller must lock nf_conntrack_lock before calling this function
 312  */
 313 static struct nf_conntrack_tuple_hash *
 314 ____nf_conntrack_find(struct net *net, u16 zone,
 315                       const struct nf_conntrack_tuple *tuple, u32 hash)
 316 {
 317         struct nf_conntrack_tuple_hash *h;
 318         struct hlist_nulls_node *n;
 319         unsigned int bucket = hash_bucket(hash, net);
 320
 321         /* Disable BHs the entire time since we normally need to disable them
 322          * at least once for the stats anyway.
 323          */
 324         local_bh_disable();
 325 begin:
 326         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
 327                 if (nf_ct_tuple_equal(tuple, &h->tuple) &&
 328                     nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) {
 329                         NF_CT_STAT_INC(net, found);
 330                         local_bh_enable();
 331                         return h;
 332                 }
 333                 NF_CT_STAT_INC(net, searched);
 334         }
 335         /*
 336          * if the nulls value we got at the end of this lookup is
 337          * not the expected one, we must restart lookup.
 338          * We probably met an item that was moved to another chain.
 339          */
 340         if (get_nulls_value(n) != bucket) {
 341                 NF_CT_STAT_INC(net, search_restart);
 342                 goto begin;
 343         }
 344         local_bh_enable();
 345
 346         return NULL;
 347 }
 348
 349 struct nf_conntrack_tuple_hash *
 350 __nf_conntrack_find(struct net *net, u16 zone,
 351                     const struct nf_conntrack_tuple *tuple)
 352 {
 353         return ____nf_conntrack_find(net, zone, tuple,
 354                                      hash_conntrack_raw(tuple, zone));
 355 }
 356 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 357
 358 /* Find a connection corresponding to a tuple. */
 359 static struct nf_conntrack_tuple_hash *
 360 __nf_conntrack_find_get(struct net *net, u16 zone,
 361                         const struct nf_conntrack_tuple *tuple, u32 hash)
 362 {
 363         struct nf_conntrack_tuple_hash *h;
 364         struct nf_conn *ct;
 365
 366         rcu_read_lock();
 367 begin:
 368         h = ____nf_conntrack_find(net, zone, tuple, hash);
 369         if (h) {
 370                 ct = nf_ct_tuplehash_to_ctrack(h);
 371                 if (unlikely(nf_ct_is_dying(ct) ||
 372                              !atomic_inc_not_zero(&ct->ct_general.use)))
 373                         h = NULL;
 374                 else {
 375                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) ||
 376                                      nf_ct_zone(ct) != zone)) {
 377                                 nf_ct_put(ct);
 378                                 goto begin;
 379                         }
 380                 }
 381         }
 382         rcu_read_unlock();
 383
 384         return h;
 385 }
 386
 387 struct nf_conntrack_tuple_hash *
 388 nf_conntrack_find_get(struct net *net, u16 zone,
 389                       const struct nf_conntrack_tuple *tuple)
 390 {
 391         return __nf_conntrack_find_get(net, zone, tuple,
 392                                        hash_conntrack_raw(tuple, zone));
 393 }
 394 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 395
 396 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 397                                        unsigned int hash,
 398                                        unsigned int repl_hash)
 399 {
 400         struct net *net = nf_ct_net(ct);
 401
 402         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 403                            &net->ct.hash[hash]);
 404         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 405                            &net->ct.hash[repl_hash]);
 406 }
 407
 408 int
 409 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 410 {
 411         struct net *net = nf_ct_net(ct);
 412         unsigned int hash, repl_hash;
 413         struct nf_conntrack_tuple_hash *h;
 414         struct hlist_nulls_node *n;
 415         u16 zone;
 416
 417         zone = nf_ct_zone(ct);
 418         hash = hash_conntrack(net, zone,
 419                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 420         repl_hash = hash_conntrack(net, zone,
 421                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 422
 423         spin_lock_bh(&nf_conntrack_lock);
 424
 425         /* See if there's one in the list already, including reverse */
 426         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 427                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 428                                       &h->tuple) &&
 429                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 430                         goto out;
 431         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 432                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 433                                       &h->tuple) &&
 434                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 435                         goto out;
 436
 437         add_timer(&ct->timeout);
 438         nf_conntrack_get(&ct->ct_general);
 439         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 440         NF_CT_STAT_INC(net, insert);
 441         spin_unlock_bh(&nf_conntrack_lock);
 442
 443         return 0;
 444
 445 out:
 446         NF_CT_STAT_INC(net, insert_failed);
 447         spin_unlock_bh(&nf_conntrack_lock);
 448         return -EEXIST;
 449 }
 450 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 451
 452 /* Confirm a connection given skb; places it in hash table */
 453 int
 454 __nf_conntrack_confirm(struct sk_buff *skb)
 455 {
 456         unsigned int hash, repl_hash;
 457         struct nf_conntrack_tuple_hash *h;
 458         struct nf_conn *ct;
 459         struct nf_conn_help *help;
 460         struct nf_conn_tstamp *tstamp;
 461         struct hlist_nulls_node *n;
 462         enum ip_conntrack_info ctinfo;
 463         struct net *net;
 464         u16 zone;
 465
 466         ct = nf_ct_get(skb, &ctinfo);
 467         net = nf_ct_net(ct);
 468
 469         /* ipt_REJECT uses nf_conntrack_attach to attach related
 470            ICMP/TCP RST packets in other direction.  Actual packet
 471            which created connection will be IP_CT_NEW or for an
 472            expected connection, IP_CT_RELATED. */
 473         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 474                 return NF_ACCEPT;
 475
 476         zone = nf_ct_zone(ct);
 477         /* reuse the hash saved before */
 478         hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 479         hash = hash_bucket(hash, net);
 480         repl_hash = hash_conntrack(net, zone,
 481                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 482
 483         /* We're not in hash table, and we refuse to set up related
 484            connections for unconfirmed conns.  But packet copies and
 485            REJECT will give spurious warnings here. */
 486         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 487
 488         /* No external references means no one else could have
 489            confirmed us. */
 490         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 491         pr_debug("Confirming conntrack %p\n", ct);
 492
 493         spin_lock_bh(&nf_conntrack_lock);
 494
 495         /* We have to check the DYING flag inside the lock to prevent
 496            a race against nf_ct_get_next_corpse() possibly called from
 497            user context, else we insert an already 'dead' hash, blocking
 498            further use of that particular connection -JM */
 499
 500         if (unlikely(nf_ct_is_dying(ct))) {
 501                 spin_unlock_bh(&nf_conntrack_lock);
 502                 return NF_ACCEPT;
 503         }
 504
 505         /* See if there's one in the list already, including reverse:
 506            NAT could have grabbed it without realizing, since we're
 507            not in the hash.  If there is, we lost race. */
 508         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 509                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 510                                       &h->tuple) &&
 511                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 512                         goto out;
 513         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 514                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 515                                       &h->tuple) &&
 516                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 517                         goto out;
 518
 519         /* Remove from unconfirmed list */
 520         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 521
 522         /* Timer relative to confirmation time, not original
 523            setting time, otherwise we'd get timer wrap in
 524            weird delay cases. */
 525         ct->timeout.expires += jiffies;
 526         add_timer(&ct->timeout);
 527         atomic_inc(&ct->ct_general.use);
 528         ct->status |= IPS_CONFIRMED;
 529
 530         /* set conntrack timestamp, if enabled. */
 531         tstamp = nf_conn_tstamp_find(ct);
 532         if (tstamp) {
 533                 if (skb->tstamp.tv64 == 0)
 534                         __net_timestamp(skb);
 535
 536                 tstamp->start = ktime_to_ns(skb->tstamp);
 537         }
 538         /* Since the lookup is lockless, hash insertion must be done after
 539          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 540          * guarantee that no other CPU can find the conntrack before the above
 541          * stores are visible.
 542          */
 543         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 544         NF_CT_STAT_INC(net, insert);
 545         spin_unlock_bh(&nf_conntrack_lock);
 546
 547         help = nfct_help(ct);
 548         if (help && help->helper)
 549                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 550
 551         nf_conntrack_event_cache(master_ct(ct) ?
 552                                  IPCT_RELATED : IPCT_NEW, ct);
 553         return NF_ACCEPT;
 554
 555 out:
 556         NF_CT_STAT_INC(net, insert_failed);
 557         spin_unlock_bh(&nf_conntrack_lock);
 558         return NF_DROP;
 559 }
 560 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 561
 562 /* Returns true if a connection correspondings to the tuple (required
 563    for NAT). */
 564 int
 565 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 566                          const struct nf_conn *ignored_conntrack)
 567 {
 568         struct net *net = nf_ct_net(ignored_conntrack);
 569         struct nf_conntrack_tuple_hash *h;
 570         struct hlist_nulls_node *n;
 571         struct nf_conn *ct;
 572         u16 zone = nf_ct_zone(ignored_conntrack);
 573         unsigned int hash = hash_conntrack(net, zone, tuple);
 574
 575         /* Disable BHs the entire time since we need to disable them at
 576          * least once for the stats anyway.
 577          */
 578         rcu_read_lock_bh();
 579         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 580                 ct = nf_ct_tuplehash_to_ctrack(h);
 581                 if (ct != ignored_conntrack &&
 582                     nf_ct_tuple_equal(tuple, &h->tuple) &&
 583                     nf_ct_zone(ct) == zone) {
 584                         NF_CT_STAT_INC(net, found);
 585                         rcu_read_unlock_bh();
 586                         return 1;
 587                 }
 588                 NF_CT_STAT_INC(net, searched);
 589         }
 590         rcu_read_unlock_bh();
 591
 592         return 0;
 593 }
 594 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 595
 596 #define NF_CT_EVICTION_RANGE    8
 597
 598 /* There's a small race here where we may free a just-assured
 599    connection.  Too bad: we're in trouble anyway. */
 600 static noinline int early_drop(struct net *net, unsigned int hash)
 601 {
 602         /* Use oldest entry, which is roughly LRU */
 603         struct nf_conntrack_tuple_hash *h;
 604         struct nf_conn *ct = NULL, *tmp;
 605         struct hlist_nulls_node *n;
 606         unsigned int i, cnt = 0;
 607         int dropped = 0;
 608
 609         rcu_read_lock();
 610         for (i = 0; i < net->ct.htable_size; i++) {
 611                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 612                                          hnnode) {
 613                         tmp = nf_ct_tuplehash_to_ctrack(h);
 614                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 615                                 ct = tmp;
 616                         cnt++;
 617                 }
 618
 619                 if (ct != NULL) {
 620                         if (likely(!nf_ct_is_dying(ct) &&
 621                                    atomic_inc_not_zero(&ct->ct_general.use)))
 622                                 break;
 623                         else
 624                                 ct = NULL;
 625                 }
 626
 627                 if (cnt >= NF_CT_EVICTION_RANGE)
 628                         break;
 629
 630                 hash = (hash + 1) % net->ct.htable_size;
 631         }
 632         rcu_read_unlock();
 633
 634         if (!ct)
 635                 return dropped;
 636
 637         if (del_timer(&ct->timeout)) {
 638                 death_by_timeout((unsigned long)ct);
 639                 /* Check if we indeed killed this entry. Reliable event
 640                    delivery may have inserted it into the dying list. */
 641                 if (test_bit(IPS_DYING_BIT, &ct->status)) {
 642                         dropped = 1;
 643                         NF_CT_STAT_INC_ATOMIC(net, early_drop);
 644                 }
 645         }
 646         nf_ct_put(ct);
 647         return dropped;
 648 }
 649
 650 void init_nf_conntrack_hash_rnd(void)
 651 {
 652         unsigned int rand;
 653
 654         /*
 655          * Why not initialize nf_conntrack_rnd in a "init()" function ?
 656          * Because there isn't enough entropy when system initializing,
 657          * and we initialize it as late as possible.
 658          */
 659         do {
 660                 get_random_bytes(&rand, sizeof(rand));
 661         } while (!rand);
 662         cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
 663 }
 664
 665 static struct nf_conn *
 666 __nf_conntrack_alloc(struct net *net, u16 zone,
 667                      const struct nf_conntrack_tuple *orig,
 668                      const struct nf_conntrack_tuple *repl,
 669                      gfp_t gfp, u32 hash)
 670 {
 671         struct nf_conn *ct;
 672
 673         if (unlikely(!nf_conntrack_hash_rnd)) {
 674                 init_nf_conntrack_hash_rnd();
 675                 /* recompute the hash as nf_conntrack_hash_rnd is initialized */
 676                 hash = hash_conntrack_raw(orig, zone);
 677         }
 678
 679         /* We don't want any race condition at early drop stage */
 680         atomic_inc(&net->ct.count);
 681
 682         if (nf_conntrack_max &&
 683             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
 684                 if (!early_drop(net, hash_bucket(hash, net))) {
 685                         atomic_dec(&net->ct.count);
 686                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
 687                         return ERR_PTR(-ENOMEM);
 688                 }
 689         }
 690
 691         /*
 692          * Do not use kmem_cache_zalloc(), as this cache uses
 693          * SLAB_DESTROY_BY_RCU.
 694          */
 695         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
 696         if (ct == NULL) {
 697                 atomic_dec(&net->ct.count);
 698                 return ERR_PTR(-ENOMEM);
 699         }
 700         /*
 701          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
 702          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
 703          */
 704         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
 705                offsetof(struct nf_conn, proto) -
 706                offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
 707         spin_lock_init(&ct->lock);
 708         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 709         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
 710         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 711         /* save hash for reusing when confirming */
 712         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
 713         /* Don't set timer yet: wait for confirmation */
 714         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 715         write_pnet(&ct->ct_net, net);
 716 #ifdef CONFIG_NF_CONNTRACK_ZONES
 717         if (zone) {
 718                 struct nf_conntrack_zone *nf_ct_zone;
 719
 720                 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC);
 721                 if (!nf_ct_zone)
 722                         goto out_free;
 723                 nf_ct_zone->id = zone;
 724         }
 725 #endif
 726         /*
 727          * changes to lookup keys must be done before setting refcnt to 1
 728          */
 729         smp_wmb();
 730         atomic_set(&ct->ct_general.use, 1);
 731         return ct;
 732
 733 #ifdef CONFIG_NF_CONNTRACK_ZONES
 734 out_free:
 735         atomic_dec(&net->ct.count);
 736         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 737         return ERR_PTR(-ENOMEM);
 738 #endif
 739 }
 740
 741 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 742                                    const struct nf_conntrack_tuple *orig,
 743                                    const struct nf_conntrack_tuple *repl,
 744                                    gfp_t gfp)
 745 {
 746         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
 747 }
 748 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 749
 750 void nf_conntrack_free(struct nf_conn *ct)
 751 {
 752         struct net *net = nf_ct_net(ct);
 753
 754         nf_ct_ext_destroy(ct);
 755         atomic_dec(&net->ct.count);
 756         nf_ct_ext_free(ct);
 757         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 758 }
 759 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 760
 761 /* Allocate a new conntrack: we return -ENOMEM if classification
 762    failed due to stress.  Otherwise it really is unclassifiable. */
 763 static struct nf_conntrack_tuple_hash *
 764 init_conntrack(struct net *net, struct nf_conn *tmpl,
 765                const struct nf_conntrack_tuple *tuple,
 766                struct nf_conntrack_l3proto *l3proto,
 767                struct nf_conntrack_l4proto *l4proto,
 768                struct sk_buff *skb,
 769                unsigned int dataoff, u32 hash)
 770 {
 771         struct nf_conn *ct;
 772         struct nf_conn_help *help;
 773         struct nf_conntrack_tuple repl_tuple;
 774         struct nf_conntrack_ecache *ecache;
 775         struct nf_conntrack_expect *exp;
 776         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 777         struct nf_conn_timeout *timeout_ext;
 778         unsigned int *timeouts;
 779
 780         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 781                 pr_debug("Can't invert tuple.\n");
 782                 return NULL;
 783         }
 784
 785         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
 786                                   hash);
 787         if (IS_ERR(ct))
 788                 return (struct nf_conntrack_tuple_hash *)ct;
 789
 790         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
 791         if (timeout_ext)
 792                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 793         else
 794                 timeouts = l4proto->get_timeouts(net);
 795
 796         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
 797                 nf_conntrack_free(ct);
 798                 pr_debug("init conntrack: can't track with proto module\n");
 799                 return NULL;
 800         }
 801
 802         if (timeout_ext)
 803                 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC);
 804
 805         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 806         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 807
 808         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
 809         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
 810                                  ecache ? ecache->expmask : 0,
 811                              GFP_ATOMIC);
 812
 813         spin_lock_bh(&nf_conntrack_lock);
 814         exp = nf_ct_find_expectation(net, zone, tuple);
 815         if (exp) {
 816                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 817                          ct, exp);
 818                 /* Welcome, Mr. Bond.  We've been expecting you... */
 819                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
 820                 ct->master = exp->master;
 821                 if (exp->helper) {
 822                         help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
 823                         if (help)
 824                                 rcu_assign_pointer(help->helper, exp->helper);
 825                 }
 826
 827 #ifdef CONFIG_NF_CONNTRACK_MARK
 828                 ct->mark = exp->master->mark;
 829 #endif
 830 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 831                 ct->secmark = exp->master->secmark;
 832 #endif
 833                 nf_conntrack_get(&ct->master->ct_general);
 834                 NF_CT_STAT_INC(net, expect_new);
 835         } else {
 836                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
 837                 NF_CT_STAT_INC(net, new);
 838         }
 839
 840         /* Overload tuple linked list to put us in unconfirmed list. */
 841         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 842                        &net->ct.unconfirmed);
 843
 844         spin_unlock_bh(&nf_conntrack_lock);
 845
 846         if (exp) {
 847                 if (exp->expectfn)
 848                         exp->expectfn(ct, exp);
 849                 nf_ct_expect_put(exp);
 850         }
 851
 852         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
 853 }
 854
 855 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 856 static inline struct nf_conn *
 857 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
 858                   struct sk_buff *skb,
 859                   unsigned int dataoff,
 860                   u_int16_t l3num,
 861                   u_int8_t protonum,
 862                   struct nf_conntrack_l3proto *l3proto,
 863                   struct nf_conntrack_l4proto *l4proto,
 864                   int *set_reply,
 865                   enum ip_conntrack_info *ctinfo)
 866 {
 867         struct nf_conntrack_tuple tuple;
 868         struct nf_conntrack_tuple_hash *h;
 869         struct nf_conn *ct;
 870         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 871         u32 hash;
 872
 873         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 874                              dataoff, l3num, protonum, &tuple, l3proto,
 875                              l4proto)) {
 876                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 877                 return NULL;
 878         }
 879
 880         /* look for tuple match */
 881         hash = hash_conntrack_raw(&tuple, zone);
 882         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
 883         if (!h) {
 884                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
 885                                    skb, dataoff, hash);
 886                 if (!h)
 887                         return NULL;
 888                 if (IS_ERR(h))
 889                         return (void *)h;
 890         }
 891         ct = nf_ct_tuplehash_to_ctrack(h);
 892
 893         /* It exists; we have (non-exclusive) reference. */
 894         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 895                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
 896                 /* Please set reply bit if this packet OK */
 897                 *set_reply = 1;
 898         } else {
 899                 /* Once we've had two way comms, always ESTABLISHED. */
 900                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 901                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 902                         *ctinfo = IP_CT_ESTABLISHED;
 903                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 904                         pr_debug("nf_conntrack_in: related packet for %p\n",
 905                                  ct);
 906                         *ctinfo = IP_CT_RELATED;
 907                 } else {
 908                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 909                         *ctinfo = IP_CT_NEW;
 910                 }
 911                 *set_reply = 0;
 912         }
 913         skb->nfct = &ct->ct_general;
 914         skb->nfctinfo = *ctinfo;
 915         return ct;
 916 }
 917
 918 unsigned int
 919 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 920                 struct sk_buff *skb)
 921 {
 922         struct nf_conn *ct, *tmpl = NULL;
 923         enum ip_conntrack_info ctinfo;
 924         struct nf_conntrack_l3proto *l3proto;
 925         struct nf_conntrack_l4proto *l4proto;
 926         struct nf_conn_timeout *timeout_ext;
 927         unsigned int *timeouts;
 928         unsigned int dataoff;
 929         u_int8_t protonum;
 930         int set_reply = 0;
 931         int ret;
 932
 933         if (skb->nfct) {
 934                 /* Previously seen (loopback or untracked)?  Ignore. */
 935                 tmpl = (struct nf_conn *)skb->nfct;
 936                 if (!nf_ct_is_template(tmpl)) {
 937                         NF_CT_STAT_INC_ATOMIC(net, ignore);
 938                         return NF_ACCEPT;
 939                 }
 940                 skb->nfct = NULL;
 941         }
 942
 943         /* rcu_read_lock()ed by nf_hook_slow */
 944         l3proto = __nf_ct_l3proto_find(pf);
 945         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 946                                    &dataoff, &protonum);
 947         if (ret <= 0) {
 948                 pr_debug("not prepared to track yet or error occurred\n");
 949                 NF_CT_STAT_INC_ATOMIC(net, error);
 950                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 951                 ret = -ret;
 952                 goto out;
 953         }
 954
 955         l4proto = __nf_ct_l4proto_find(pf, protonum);
 956
 957         /* It may be an special packet, error, unclean...
 958          * inverse of the return code tells to the netfilter
 959          * core what to do with the packet. */
 960         if (l4proto->error != NULL) {
 961                 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
 962                                      pf, hooknum);
 963                 if (ret <= 0) {
 964                         NF_CT_STAT_INC_ATOMIC(net, error);
 965                         NF_CT_STAT_INC_ATOMIC(net, invalid);
 966                         ret = -ret;
 967                         goto out;
 968                 }
 969                 /* ICMP[v6] protocol trackers may assign one conntrack. */
 970                 if (skb->nfct)
 971                         goto out;
 972         }
 973
 974         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
 975                                l3proto, l4proto, &set_reply, &ctinfo);
 976         if (!ct) {
 977                 /* Not valid part of a connection */
 978                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 979                 ret = NF_ACCEPT;
 980                 goto out;
 981         }
 982
 983         if (IS_ERR(ct)) {
 984                 /* Too stressed to deal. */
 985                 NF_CT_STAT_INC_ATOMIC(net, drop);
 986                 ret = NF_DROP;
 987                 goto out;
 988         }
 989
 990         NF_CT_ASSERT(skb->nfct);
 991
 992         /* Decide what timeout policy we want to apply to this flow. */
 993         timeout_ext = nf_ct_timeout_find(ct);
 994         if (timeout_ext)
 995                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 996         else
 997                 timeouts = l4proto->get_timeouts(net);
 998
 999         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1000         if (ret <= 0) {
1001                 /* Invalid: inverse of the return code tells
1002                  * the netfilter core what to do */
1003                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1004                 nf_conntrack_put(skb->nfct);
1005                 skb->nfct = NULL;
1006                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1007                 if (ret == -NF_DROP)
1008                         NF_CT_STAT_INC_ATOMIC(net, drop);
1009                 ret = -ret;
1010                 goto out;
1011         }
1012
1013         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1014                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1015 out:
1016         if (tmpl) {
1017                 /* Special case: we have to repeat this hook, assign the
1018                  * template again to this packet. We assume that this packet
1019                  * has no conntrack assigned. This is used by nf_ct_tcp. */
1020                 if (ret == NF_REPEAT)
1021                         skb->nfct = (struct nf_conntrack *)tmpl;
1022                 else
1023                         nf_ct_put(tmpl);
1024         }
1025
1026         return ret;
1027 }
1028 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1029
1030 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1031                           const struct nf_conntrack_tuple *orig)
1032 {
1033         bool ret;
1034
1035         rcu_read_lock();
1036         ret = nf_ct_invert_tuple(inverse, orig,
1037                                  __nf_ct_l3proto_find(orig->src.l3num),
1038                                  __nf_ct_l4proto_find(orig->src.l3num,
1039                                                       orig->dst.protonum));
1040         rcu_read_unlock();
1041         return ret;
1042 }
1043 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1044
1045 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1046    implicitly racy: see __nf_conntrack_confirm */
1047 void nf_conntrack_alter_reply(struct nf_conn *ct,
1048                               const struct nf_conntrack_tuple *newreply)
1049 {
1050         struct nf_conn_help *help = nfct_help(ct);
1051
1052         /* Should be unconfirmed, so not in hash table yet */
1053         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1054
1055         pr_debug("Altering reply tuple of %p to ", ct);
1056         nf_ct_dump_tuple(newreply);
1057
1058         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1059         if (ct->master || (help && !hlist_empty(&help->expectations)))
1060                 return;
1061
1062         rcu_read_lock();
1063         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1064         rcu_read_unlock();
1065 }
1066 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1067
1068 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1069 void __nf_ct_refresh_acct(struct nf_conn *ct,
1070                           enum ip_conntrack_info ctinfo,
1071                           const struct sk_buff *skb,
1072                           unsigned long extra_jiffies,
1073                           int do_acct)
1074 {
1075         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1076         NF_CT_ASSERT(skb);
1077
1078         /* Only update if this is not a fixed timeout */
1079         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1080                 goto acct;
1081
1082         /* If not in hash table, timer will not be active yet */
1083         if (!nf_ct_is_confirmed(ct)) {
1084                 ct->timeout.expires = extra_jiffies;
1085         } else {
1086                 unsigned long newtime = jiffies + extra_jiffies;
1087
1088                 /* Only update the timeout if the new timeout is at least
1089                    HZ jiffies from the old timeout. Need del_timer for race
1090                    avoidance (may already be dying). */
1091                 if (newtime - ct->timeout.expires >= HZ)
1092                         mod_timer_pending(&ct->timeout, newtime);
1093         }
1094
1095 acct:
1096         if (do_acct) {
1097                 struct nf_conn_counter *acct;
1098
1099                 acct = nf_conn_acct_find(ct);
1100                 if (acct) {
1101                         atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1102                         atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes);
1103                 }
1104         }
1105 }
1106 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1107
1108 bool __nf_ct_kill_acct(struct nf_conn *ct,
1109                        enum ip_conntrack_info ctinfo,
1110                        const struct sk_buff *skb,
1111                        int do_acct)
1112 {
1113         if (do_acct) {
1114                 struct nf_conn_counter *acct;
1115
1116                 acct = nf_conn_acct_find(ct);
1117                 if (acct) {
1118                         atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1119                         atomic64_add(skb->len - skb_network_offset(skb),
1120                                      &acct[CTINFO2DIR(ctinfo)].bytes);
1121                 }
1122         }
1123
1124         if (del_timer(&ct->timeout)) {
1125                 ct->timeout.function((unsigned long)ct);
1126                 return true;
1127         }
1128         return false;
1129 }
1130 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1131
1132 #ifdef CONFIG_NF_CONNTRACK_ZONES
1133 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1134         .len    = sizeof(struct nf_conntrack_zone),
1135         .align  = __alignof__(struct nf_conntrack_zone),
1136         .id     = NF_CT_EXT_ZONE,
1137 };
1138 #endif
1139
1140 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1141
1142 #include <linux/netfilter/nfnetlink.h>
1143 #include <linux/netfilter/nfnetlink_conntrack.h>
1144 #include <linux/mutex.h>
1145
1146 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1147  * in ip_conntrack_core, since we don't want the protocols to autoload
1148  * or depend on ctnetlink */
1149 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1150                                const struct nf_conntrack_tuple *tuple)
1151 {
1152         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1153             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1154                 goto nla_put_failure;
1155         return 0;
1156
1157 nla_put_failure:
1158         return -1;
1159 }
1160 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1161
1162 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1163         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1164         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1165 };
1166 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1167
1168 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1169                                struct nf_conntrack_tuple *t)
1170 {
1171         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1172                 return -EINVAL;
1173
1174         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1175         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1176
1177         return 0;
1178 }
1179 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1180
1181 int nf_ct_port_nlattr_tuple_size(void)
1182 {
1183         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1184 }
1185 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1186 #endif
1187
1188 /* Used by ipt_REJECT and ip6t_REJECT. */
1189 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1190 {
1191         struct nf_conn *ct;
1192         enum ip_conntrack_info ctinfo;
1193
1194         /* This ICMP is in reverse direction to the packet which caused it */
1195         ct = nf_ct_get(skb, &ctinfo);
1196         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1197                 ctinfo = IP_CT_RELATED_REPLY;
1198         else
1199                 ctinfo = IP_CT_RELATED;
1200
1201         /* Attach to new skbuff, and increment count */
1202         nskb->nfct = &ct->ct_general;
1203         nskb->nfctinfo = ctinfo;
1204         nf_conntrack_get(nskb->nfct);
1205 }
1206
1207 /* Bring out ya dead! */
1208 static struct nf_conn *
1209 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1210                 void *data, unsigned int *bucket)
1211 {
1212         struct nf_conntrack_tuple_hash *h;
1213         struct nf_conn *ct;
1214         struct hlist_nulls_node *n;
1215
1216         spin_lock_bh(&nf_conntrack_lock);
1217         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1218                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1219                         ct = nf_ct_tuplehash_to_ctrack(h);
1220                         if (iter(ct, data))
1221                                 goto found;
1222                 }
1223         }
1224         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1225                 ct = nf_ct_tuplehash_to_ctrack(h);
1226                 if (iter(ct, data))
1227                         set_bit(IPS_DYING_BIT, &ct->status);
1228         }
1229         spin_unlock_bh(&nf_conntrack_lock);
1230         return NULL;
1231 found:
1232         atomic_inc(&ct->ct_general.use);
1233         spin_unlock_bh(&nf_conntrack_lock);
1234         return ct;
1235 }
1236
1237 void nf_ct_iterate_cleanup(struct net *net,
1238                            int (*iter)(struct nf_conn *i, void *data),
1239                            void *data)
1240 {
1241         struct nf_conn *ct;
1242         unsigned int bucket = 0;
1243
1244         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1245                 /* Time to push up daises... */
1246                 if (del_timer(&ct->timeout))
1247                         death_by_timeout((unsigned long)ct);
1248                 /* ... else the timer will get him soon. */
1249
1250                 nf_ct_put(ct);
1251         }
1252 }
1253 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1254
1255 struct __nf_ct_flush_report {
1256         u32 pid;
1257         int report;
1258 };
1259
1260 static int kill_report(struct nf_conn *i, void *data)
1261 {
1262         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1263         struct nf_conn_tstamp *tstamp;
1264
1265         tstamp = nf_conn_tstamp_find(i);
1266         if (tstamp && tstamp->stop == 0)
1267                 tstamp->stop = ktime_to_ns(ktime_get_real());
1268
1269         /* If we fail to deliver the event, death_by_timeout() will retry */
1270         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1271                                       fr->pid, fr->report) < 0)
1272                 return 1;
1273
1274         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1275         set_bit(IPS_DYING_BIT, &i->status);
1276         return 1;
1277 }
1278
1279 static int kill_all(struct nf_conn *i, void *data)
1280 {
1281         return 1;
1282 }
1283
1284 void nf_ct_free_hashtable(void *hash, unsigned int size)
1285 {
1286         if (is_vmalloc_addr(hash))
1287                 vfree(hash);
1288         else
1289                 free_pages((unsigned long)hash,
1290                            get_order(sizeof(struct hlist_head) * size));
1291 }
1292 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1293
1294 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1295 {
1296         struct __nf_ct_flush_report fr = {
1297                 .pid    = pid,
1298                 .report = report,
1299         };
1300         nf_ct_iterate_cleanup(net, kill_report, &fr);
1301 }
1302 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1303
1304 static void nf_ct_release_dying_list(struct net *net)
1305 {
1306         struct nf_conntrack_tuple_hash *h;
1307         struct nf_conn *ct;
1308         struct hlist_nulls_node *n;
1309
1310         spin_lock_bh(&nf_conntrack_lock);
1311         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1312                 ct = nf_ct_tuplehash_to_ctrack(h);
1313                 /* never fails to remove them, no listeners at this point */
1314                 nf_ct_kill(ct);
1315         }
1316         spin_unlock_bh(&nf_conntrack_lock);
1317 }
1318
1319 static int untrack_refs(void)
1320 {
1321         int cnt = 0, cpu;
1322
1323         for_each_possible_cpu(cpu) {
1324                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1325
1326                 cnt += atomic_read(&ct->ct_general.use) - 1;
1327         }
1328         return cnt;
1329 }
1330
1331 static void nf_conntrack_cleanup_init_net(void)
1332 {
1333         while (untrack_refs() > 0)
1334                 schedule();
1335
1336 #ifdef CONFIG_NF_CONNTRACK_ZONES
1337         nf_ct_extend_unregister(&nf_ct_zone_extend);
1338 #endif
1339 }
1340
1341 static void nf_conntrack_cleanup_net(struct net *net)
1342 {
1343  i_see_dead_people:
1344         nf_ct_iterate_cleanup(net, kill_all, NULL);
1345         nf_ct_release_dying_list(net);
1346         if (atomic_read(&net->ct.count) != 0) {
1347                 schedule();
1348                 goto i_see_dead_people;
1349         }
1350
1351         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1352         nf_conntrack_helper_fini(net);
1353         nf_conntrack_timeout_fini(net);
1354         nf_conntrack_ecache_fini(net);
1355         nf_conntrack_tstamp_fini(net);
1356         nf_conntrack_acct_fini(net);
1357         nf_conntrack_expect_fini(net);
1358         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1359         kfree(net->ct.slabname);
1360         free_percpu(net->ct.stat);
1361 }
1362
1363 /* Mishearing the voices in his head, our hero wonders how he's
1364    supposed to kill the mall. */
1365 void nf_conntrack_cleanup(struct net *net)
1366 {
1367         if (net_eq(net, &init_net))
1368                 RCU_INIT_POINTER(ip_ct_attach, NULL);
1369
1370         /* This makes sure all current packets have passed through
1371            netfilter framework.  Roll on, two-stage module
1372            delete... */
1373         synchronize_net();
1374         nf_conntrack_proto_fini(net);
1375         nf_conntrack_cleanup_net(net);
1376
1377         if (net_eq(net, &init_net)) {
1378                 RCU_INIT_POINTER(nf_ct_destroy, NULL);
1379                 nf_conntrack_cleanup_init_net();
1380         }
1381 }
1382
1383 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1384 {
1385         struct hlist_nulls_head *hash;
1386         unsigned int nr_slots, i;
1387         size_t sz;
1388
1389         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1390         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1391         sz = nr_slots * sizeof(struct hlist_nulls_head);
1392         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1393                                         get_order(sz));
1394         if (!hash) {
1395                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1396                 hash = vzalloc(sz);
1397         }
1398
1399         if (hash && nulls)
1400                 for (i = 0; i < nr_slots; i++)
1401                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1402
1403         return hash;
1404 }
1405 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1406
1407 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1408 {
1409         int i, bucket;
1410         unsigned int hashsize, old_size;
1411         struct hlist_nulls_head *hash, *old_hash;
1412         struct nf_conntrack_tuple_hash *h;
1413         struct nf_conn *ct;
1414
1415         if (current->nsproxy->net_ns != &init_net)
1416                 return -EOPNOTSUPP;
1417
1418         /* On boot, we can set this without any fancy locking. */
1419         if (!nf_conntrack_htable_size)
1420                 return param_set_uint(val, kp);
1421
1422         hashsize = simple_strtoul(val, NULL, 0);
1423         if (!hashsize)
1424                 return -EINVAL;
1425
1426         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1427         if (!hash)
1428                 return -ENOMEM;
1429
1430         /* Lookups in the old hash might happen in parallel, which means we
1431          * might get false negatives during connection lookup. New connections
1432          * created because of a false negative won't make it into the hash
1433          * though since that required taking the lock.
1434          */
1435         spin_lock_bh(&nf_conntrack_lock);
1436         for (i = 0; i < init_net.ct.htable_size; i++) {
1437                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1438                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1439                                         struct nf_conntrack_tuple_hash, hnnode);
1440                         ct = nf_ct_tuplehash_to_ctrack(h);
1441                         hlist_nulls_del_rcu(&h->hnnode);
1442                         bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct),
1443                                                   hashsize);
1444                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1445                 }
1446         }
1447         old_size = init_net.ct.htable_size;
1448         old_hash = init_net.ct.hash;
1449
1450         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1451         init_net.ct.hash = hash;
1452         spin_unlock_bh(&nf_conntrack_lock);
1453
1454         nf_ct_free_hashtable(old_hash, old_size);
1455         return 0;
1456 }
1457 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1458
1459 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1460                   &nf_conntrack_htable_size, 0600);
1461
1462 void nf_ct_untracked_status_or(unsigned long bits)
1463 {
1464         int cpu;
1465
1466         for_each_possible_cpu(cpu)
1467                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1468 }
1469 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1470
1471 static int nf_conntrack_init_init_net(void)
1472 {
1473         int max_factor = 8;
1474         int ret, cpu;
1475
1476         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1477          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1478         if (!nf_conntrack_htable_size) {
1479                 nf_conntrack_htable_size
1480                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1481                            / sizeof(struct hlist_head));
1482                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1483                         nf_conntrack_htable_size = 16384;
1484                 if (nf_conntrack_htable_size < 32)
1485                         nf_conntrack_htable_size = 32;
1486
1487                 /* Use a max. factor of four by default to get the same max as
1488                  * with the old struct list_heads. When a table size is given
1489                  * we use the old value of 8 to avoid reducing the max.
1490                  * entries. */
1491                 max_factor = 4;
1492         }
1493         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1494
1495         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1496                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1497                nf_conntrack_max);
1498 #ifdef CONFIG_NF_CONNTRACK_ZONES
1499         ret = nf_ct_extend_register(&nf_ct_zone_extend);
1500         if (ret < 0)
1501                 goto err_extend;
1502 #endif
1503         /* Set up fake conntrack: to never be deleted, not in any hashes */
1504         for_each_possible_cpu(cpu) {
1505                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1506                 write_pnet(&ct->ct_net, &init_net);
1507                 atomic_set(&ct->ct_general.use, 1);
1508         }
1509         /*  - and look it like as a confirmed connection */
1510         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1511         return 0;
1512
1513 #ifdef CONFIG_NF_CONNTRACK_ZONES
1514 err_extend:
1515 #endif
1516         return ret;
1517 }
1518
1519 /*
1520  * We need to use special "null" values, not used in hash table
1521  */
1522 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1523 #define DYING_NULLS_VAL         ((1<<30)+1)
1524
1525 static int nf_conntrack_init_net(struct net *net)
1526 {
1527         int ret;
1528
1529         atomic_set(&net->ct.count, 0);
1530         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1531         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1532         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1533         if (!net->ct.stat) {
1534                 ret = -ENOMEM;
1535                 goto err_stat;
1536         }
1537
1538         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1539         if (!net->ct.slabname) {
1540                 ret = -ENOMEM;
1541                 goto err_slabname;
1542         }
1543
1544         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1545                                                         sizeof(struct nf_conn), 0,
1546                                                         SLAB_DESTROY_BY_RCU, NULL);
1547         if (!net->ct.nf_conntrack_cachep) {
1548                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1549                 ret = -ENOMEM;
1550                 goto err_cache;
1551         }
1552
1553         net->ct.htable_size = nf_conntrack_htable_size;
1554         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1555         if (!net->ct.hash) {
1556                 ret = -ENOMEM;
1557                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1558                 goto err_hash;
1559         }
1560         ret = nf_conntrack_expect_init(net);
1561         if (ret < 0)
1562                 goto err_expect;
1563         ret = nf_conntrack_acct_init(net);
1564         if (ret < 0)
1565                 goto err_acct;
1566         ret = nf_conntrack_tstamp_init(net);
1567         if (ret < 0)
1568                 goto err_tstamp;
1569         ret = nf_conntrack_ecache_init(net);
1570         if (ret < 0)
1571                 goto err_ecache;
1572         ret = nf_conntrack_timeout_init(net);
1573         if (ret < 0)
1574                 goto err_timeout;
1575         ret = nf_conntrack_helper_init(net);
1576         if (ret < 0)
1577                 goto err_helper;
1578         return 0;
1579 err_helper:
1580         nf_conntrack_timeout_fini(net);
1581 err_timeout:
1582         nf_conntrack_ecache_fini(net);
1583 err_ecache:
1584         nf_conntrack_tstamp_fini(net);
1585 err_tstamp:
1586         nf_conntrack_acct_fini(net);
1587 err_acct:
1588         nf_conntrack_expect_fini(net);
1589 err_expect:
1590         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1591 err_hash:
1592         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1593 err_cache:
1594         kfree(net->ct.slabname);
1595 err_slabname:
1596         free_percpu(net->ct.stat);
1597 err_stat:
1598         return ret;
1599 }
1600
1601 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1602                         enum ip_conntrack_dir dir,
1603                         u32 seq);
1604 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1605
1606 int nf_conntrack_init(struct net *net)
1607 {
1608         int ret;
1609
1610         if (net_eq(net, &init_net)) {
1611                 ret = nf_conntrack_init_init_net();
1612                 if (ret < 0)
1613                         goto out_init_net;
1614         }
1615         ret = nf_conntrack_proto_init(net);
1616         if (ret < 0)
1617                 goto out_proto;
1618         ret = nf_conntrack_init_net(net);
1619         if (ret < 0)
1620                 goto out_net;
1621
1622         if (net_eq(net, &init_net)) {
1623                 /* For use by REJECT target */
1624                 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1625                 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1626
1627                 /* Howto get NAT offsets */
1628                 RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
1629         }
1630         return 0;
1631
1632 out_net:
1633         nf_conntrack_proto_fini(net);
1634 out_proto:
1635         if (net_eq(net, &init_net))
1636                 nf_conntrack_cleanup_init_net();
1637 out_init_net:
1638         return ret;
1639 }