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 int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
  59                               struct nf_conn *ct,
  60                               enum ip_conntrack_info ctinfo,
  61                               unsigned int protoff);
  62 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
  63
  64 DEFINE_SPINLOCK(nf_conntrack_lock);
  65 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  66
  67 unsigned int nf_conntrack_htable_size __read_mostly;
  68 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  69
  70 unsigned int nf_conntrack_max __read_mostly;
  71 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  72
  73 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
  74 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
  75
  76 unsigned int nf_conntrack_hash_rnd __read_mostly;
  77 EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd);
  78
  79 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone)
  80 {
  81         unsigned int n;
  82
  83         /* The direction must be ignored, so we hash everything up to the
  84          * destination ports (which is a multiple of 4) and treat the last
  85          * three bytes manually.
  86          */
  87         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
  88         return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^
  89                       (((__force __u16)tuple->dst.u.all << 16) |
  90                       tuple->dst.protonum));
  91 }
  92
  93 static u32 __hash_bucket(u32 hash, unsigned int size)
  94 {
  95         return ((u64)hash * size) >> 32;
  96 }
  97
  98 static u32 hash_bucket(u32 hash, const struct net *net)
  99 {
 100         return __hash_bucket(hash, net->ct.htable_size);
 101 }
 102
 103 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 104                                   u16 zone, unsigned int size)
 105 {
 106         return __hash_bucket(hash_conntrack_raw(tuple, zone), size);
 107 }
 108
 109 static inline u_int32_t hash_conntrack(const struct net *net, u16 zone,
 110                                        const struct nf_conntrack_tuple *tuple)
 111 {
 112         return __hash_conntrack(tuple, zone, net->ct.htable_size);
 113 }
 114
 115 bool
 116 nf_ct_get_tuple(const struct sk_buff *skb,
 117                 unsigned int nhoff,
 118                 unsigned int dataoff,
 119                 u_int16_t l3num,
 120                 u_int8_t protonum,
 121                 struct nf_conntrack_tuple *tuple,
 122                 const struct nf_conntrack_l3proto *l3proto,
 123                 const struct nf_conntrack_l4proto *l4proto)
 124 {
 125         memset(tuple, 0, sizeof(*tuple));
 126
 127         tuple->src.l3num = l3num;
 128         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 129                 return false;
 130
 131         tuple->dst.protonum = protonum;
 132         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 133
 134         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 135 }
 136 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 137
 138 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 139                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
 140 {
 141         struct nf_conntrack_l3proto *l3proto;
 142         struct nf_conntrack_l4proto *l4proto;
 143         unsigned int protoff;
 144         u_int8_t protonum;
 145         int ret;
 146
 147         rcu_read_lock();
 148
 149         l3proto = __nf_ct_l3proto_find(l3num);
 150         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 151         if (ret != NF_ACCEPT) {
 152                 rcu_read_unlock();
 153                 return false;
 154         }
 155
 156         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 157
 158         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 159                               l3proto, l4proto);
 160
 161         rcu_read_unlock();
 162         return ret;
 163 }
 164 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 165
 166 bool
 167 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 168                    const struct nf_conntrack_tuple *orig,
 169                    const struct nf_conntrack_l3proto *l3proto,
 170                    const struct nf_conntrack_l4proto *l4proto)
 171 {
 172         memset(inverse, 0, sizeof(*inverse));
 173
 174         inverse->src.l3num = orig->src.l3num;
 175         if (l3proto->invert_tuple(inverse, orig) == 0)
 176                 return false;
 177
 178         inverse->dst.dir = !orig->dst.dir;
 179
 180         inverse->dst.protonum = orig->dst.protonum;
 181         return l4proto->invert_tuple(inverse, orig);
 182 }
 183 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 184
 185 static void
 186 clean_from_lists(struct nf_conn *ct)
 187 {
 188         pr_debug("clean_from_lists(%p)\n", ct);
 189         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 190         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 191
 192         /* Destroy all pending expectations */
 193         nf_ct_remove_expectations(ct);
 194 }
 195
 196 static void
 197 destroy_conntrack(struct nf_conntrack *nfct)
 198 {
 199         struct nf_conn *ct = (struct nf_conn *)nfct;
 200         struct net *net = nf_ct_net(ct);
 201         struct nf_conntrack_l4proto *l4proto;
 202
 203         pr_debug("destroy_conntrack(%p)\n", ct);
 204         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 205         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 206
 207         /* To make sure we don't get any weird locking issues here:
 208          * destroy_conntrack() MUST NOT be called with a write lock
 209          * to nf_conntrack_lock!!! -HW */
 210         rcu_read_lock();
 211         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 212         if (l4proto && l4proto->destroy)
 213                 l4proto->destroy(ct);
 214
 215         rcu_read_unlock();
 216
 217         spin_lock_bh(&nf_conntrack_lock);
 218         /* Expectations will have been removed in clean_from_lists,
 219          * except TFTP can create an expectation on the first packet,
 220          * before connection is in the list, so we need to clean here,
 221          * too. */
 222         nf_ct_remove_expectations(ct);
 223
 224         /* We overload first tuple to link into unconfirmed list. */
 225         if (!nf_ct_is_confirmed(ct)) {
 226                 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 227                 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 228         }
 229
 230         NF_CT_STAT_INC(net, delete);
 231         spin_unlock_bh(&nf_conntrack_lock);
 232
 233         if (ct->master)
 234                 nf_ct_put(ct->master);
 235
 236         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 237         nf_conntrack_free(ct);
 238 }
 239
 240 void nf_ct_delete_from_lists(struct nf_conn *ct)
 241 {
 242         struct net *net = nf_ct_net(ct);
 243
 244         nf_ct_helper_destroy(ct);
 245         spin_lock_bh(&nf_conntrack_lock);
 246         /* Inside lock so preempt is disabled on module removal path.
 247          * Otherwise we can get spurious warnings. */
 248         NF_CT_STAT_INC(net, delete_list);
 249         clean_from_lists(ct);
 250         spin_unlock_bh(&nf_conntrack_lock);
 251 }
 252 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
 253
 254 static void death_by_event(unsigned long ul_conntrack)
 255 {
 256         struct nf_conn *ct = (void *)ul_conntrack;
 257         struct net *net = nf_ct_net(ct);
 258
 259         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
 260                 /* bad luck, let's retry again */
 261                 ct->timeout.expires = jiffies +
 262                         (random32() % net->ct.sysctl_events_retry_timeout);
 263                 add_timer(&ct->timeout);
 264                 return;
 265         }
 266         /* we've got the event delivered, now it's dying */
 267         set_bit(IPS_DYING_BIT, &ct->status);
 268         spin_lock(&nf_conntrack_lock);
 269         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 270         spin_unlock(&nf_conntrack_lock);
 271         nf_ct_put(ct);
 272 }
 273
 274 void nf_ct_insert_dying_list(struct nf_conn *ct)
 275 {
 276         struct net *net = nf_ct_net(ct);
 277
 278         /* add this conntrack to the dying list */
 279         spin_lock_bh(&nf_conntrack_lock);
 280         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 281                              &net->ct.dying);
 282         spin_unlock_bh(&nf_conntrack_lock);
 283         /* set a new timer to retry event delivery */
 284         setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
 285         ct->timeout.expires = jiffies +
 286                 (random32() % net->ct.sysctl_events_retry_timeout);
 287         add_timer(&ct->timeout);
 288 }
 289 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
 290
 291 static void death_by_timeout(unsigned long ul_conntrack)
 292 {
 293         struct nf_conn *ct = (void *)ul_conntrack;
 294         struct nf_conn_tstamp *tstamp;
 295
 296         tstamp = nf_conn_tstamp_find(ct);
 297         if (tstamp && tstamp->stop == 0)
 298                 tstamp->stop = ktime_to_ns(ktime_get_real());
 299
 300         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
 301             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
 302                 /* destroy event was not delivered */
 303                 nf_ct_delete_from_lists(ct);
 304                 nf_ct_insert_dying_list(ct);
 305                 return;
 306         }
 307         set_bit(IPS_DYING_BIT, &ct->status);
 308         nf_ct_delete_from_lists(ct);
 309         nf_ct_put(ct);
 310 }
 311
 312 /*
 313  * Warning :
 314  * - Caller must take a reference on returned object
 315  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 316  * OR
 317  * - Caller must lock nf_conntrack_lock before calling this function
 318  */
 319 static struct nf_conntrack_tuple_hash *
 320 ____nf_conntrack_find(struct net *net, u16 zone,
 321                       const struct nf_conntrack_tuple *tuple, u32 hash)
 322 {
 323         struct nf_conntrack_tuple_hash *h;
 324         struct hlist_nulls_node *n;
 325         unsigned int bucket = hash_bucket(hash, net);
 326
 327         /* Disable BHs the entire time since we normally need to disable them
 328          * at least once for the stats anyway.
 329          */
 330         local_bh_disable();
 331 begin:
 332         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
 333                 if (nf_ct_tuple_equal(tuple, &h->tuple) &&
 334                     nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) {
 335                         NF_CT_STAT_INC(net, found);
 336                         local_bh_enable();
 337                         return h;
 338                 }
 339                 NF_CT_STAT_INC(net, searched);
 340         }
 341         /*
 342          * if the nulls value we got at the end of this lookup is
 343          * not the expected one, we must restart lookup.
 344          * We probably met an item that was moved to another chain.
 345          */
 346         if (get_nulls_value(n) != bucket) {
 347                 NF_CT_STAT_INC(net, search_restart);
 348                 goto begin;
 349         }
 350         local_bh_enable();
 351
 352         return NULL;
 353 }
 354
 355 struct nf_conntrack_tuple_hash *
 356 __nf_conntrack_find(struct net *net, u16 zone,
 357                     const struct nf_conntrack_tuple *tuple)
 358 {
 359         return ____nf_conntrack_find(net, zone, tuple,
 360                                      hash_conntrack_raw(tuple, zone));
 361 }
 362 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 363
 364 /* Find a connection corresponding to a tuple. */
 365 static struct nf_conntrack_tuple_hash *
 366 __nf_conntrack_find_get(struct net *net, u16 zone,
 367                         const struct nf_conntrack_tuple *tuple, u32 hash)
 368 {
 369         struct nf_conntrack_tuple_hash *h;
 370         struct nf_conn *ct;
 371
 372         rcu_read_lock();
 373 begin:
 374         h = ____nf_conntrack_find(net, zone, tuple, hash);
 375         if (h) {
 376                 ct = nf_ct_tuplehash_to_ctrack(h);
 377                 if (unlikely(nf_ct_is_dying(ct) ||
 378                              !atomic_inc_not_zero(&ct->ct_general.use)))
 379                         h = NULL;
 380                 else {
 381                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) ||
 382                                      nf_ct_zone(ct) != zone)) {
 383                                 nf_ct_put(ct);
 384                                 goto begin;
 385                         }
 386                 }
 387         }
 388         rcu_read_unlock();
 389
 390         return h;
 391 }
 392
 393 struct nf_conntrack_tuple_hash *
 394 nf_conntrack_find_get(struct net *net, u16 zone,
 395                       const struct nf_conntrack_tuple *tuple)
 396 {
 397         return __nf_conntrack_find_get(net, zone, tuple,
 398                                        hash_conntrack_raw(tuple, zone));
 399 }
 400 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 401
 402 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 403                                        unsigned int hash,
 404                                        unsigned int repl_hash)
 405 {
 406         struct net *net = nf_ct_net(ct);
 407
 408         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 409                            &net->ct.hash[hash]);
 410         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 411                            &net->ct.hash[repl_hash]);
 412 }
 413
 414 int
 415 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 416 {
 417         struct net *net = nf_ct_net(ct);
 418         unsigned int hash, repl_hash;
 419         struct nf_conntrack_tuple_hash *h;
 420         struct hlist_nulls_node *n;
 421         u16 zone;
 422
 423         zone = nf_ct_zone(ct);
 424         hash = hash_conntrack(net, zone,
 425                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 426         repl_hash = hash_conntrack(net, zone,
 427                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 428
 429         spin_lock_bh(&nf_conntrack_lock);
 430
 431         /* See if there's one in the list already, including reverse */
 432         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 433                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 434                                       &h->tuple) &&
 435                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 436                         goto out;
 437         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 438                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 439                                       &h->tuple) &&
 440                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 441                         goto out;
 442
 443         add_timer(&ct->timeout);
 444         nf_conntrack_get(&ct->ct_general);
 445         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 446         NF_CT_STAT_INC(net, insert);
 447         spin_unlock_bh(&nf_conntrack_lock);
 448
 449         return 0;
 450
 451 out:
 452         NF_CT_STAT_INC(net, insert_failed);
 453         spin_unlock_bh(&nf_conntrack_lock);
 454         return -EEXIST;
 455 }
 456 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 457
 458 /* Confirm a connection given skb; places it in hash table */
 459 int
 460 __nf_conntrack_confirm(struct sk_buff *skb)
 461 {
 462         unsigned int hash, repl_hash;
 463         struct nf_conntrack_tuple_hash *h;
 464         struct nf_conn *ct;
 465         struct nf_conn_help *help;
 466         struct nf_conn_tstamp *tstamp;
 467         struct hlist_nulls_node *n;
 468         enum ip_conntrack_info ctinfo;
 469         struct net *net;
 470         u16 zone;
 471
 472         ct = nf_ct_get(skb, &ctinfo);
 473         net = nf_ct_net(ct);
 474
 475         /* ipt_REJECT uses nf_conntrack_attach to attach related
 476            ICMP/TCP RST packets in other direction.  Actual packet
 477            which created connection will be IP_CT_NEW or for an
 478            expected connection, IP_CT_RELATED. */
 479         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 480                 return NF_ACCEPT;
 481
 482         zone = nf_ct_zone(ct);
 483         /* reuse the hash saved before */
 484         hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 485         hash = hash_bucket(hash, net);
 486         repl_hash = hash_conntrack(net, zone,
 487                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 488
 489         /* We're not in hash table, and we refuse to set up related
 490            connections for unconfirmed conns.  But packet copies and
 491            REJECT will give spurious warnings here. */
 492         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 493
 494         /* No external references means no one else could have
 495            confirmed us. */
 496         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 497         pr_debug("Confirming conntrack %p\n", ct);
 498
 499         spin_lock_bh(&nf_conntrack_lock);
 500
 501         /* We have to check the DYING flag inside the lock to prevent
 502            a race against nf_ct_get_next_corpse() possibly called from
 503            user context, else we insert an already 'dead' hash, blocking
 504            further use of that particular connection -JM */
 505
 506         if (unlikely(nf_ct_is_dying(ct))) {
 507                 spin_unlock_bh(&nf_conntrack_lock);
 508                 return NF_ACCEPT;
 509         }
 510
 511         /* See if there's one in the list already, including reverse:
 512            NAT could have grabbed it without realizing, since we're
 513            not in the hash.  If there is, we lost race. */
 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[repl_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         /* Remove from unconfirmed list */
 526         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 527
 528         /* Timer relative to confirmation time, not original
 529            setting time, otherwise we'd get timer wrap in
 530            weird delay cases. */
 531         ct->timeout.expires += jiffies;
 532         add_timer(&ct->timeout);
 533         atomic_inc(&ct->ct_general.use);
 534         ct->status |= IPS_CONFIRMED;
 535
 536         /* set conntrack timestamp, if enabled. */
 537         tstamp = nf_conn_tstamp_find(ct);
 538         if (tstamp) {
 539                 if (skb->tstamp.tv64 == 0)
 540                         __net_timestamp(skb);
 541
 542                 tstamp->start = ktime_to_ns(skb->tstamp);
 543         }
 544         /* Since the lookup is lockless, hash insertion must be done after
 545          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 546          * guarantee that no other CPU can find the conntrack before the above
 547          * stores are visible.
 548          */
 549         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 550         NF_CT_STAT_INC(net, insert);
 551         spin_unlock_bh(&nf_conntrack_lock);
 552
 553         help = nfct_help(ct);
 554         if (help && help->helper)
 555                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 556
 557         nf_conntrack_event_cache(master_ct(ct) ?
 558                                  IPCT_RELATED : IPCT_NEW, ct);
 559         return NF_ACCEPT;
 560
 561 out:
 562         NF_CT_STAT_INC(net, insert_failed);
 563         spin_unlock_bh(&nf_conntrack_lock);
 564         return NF_DROP;
 565 }
 566 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 567
 568 /* Returns true if a connection correspondings to the tuple (required
 569    for NAT). */
 570 int
 571 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 572                          const struct nf_conn *ignored_conntrack)
 573 {
 574         struct net *net = nf_ct_net(ignored_conntrack);
 575         struct nf_conntrack_tuple_hash *h;
 576         struct hlist_nulls_node *n;
 577         struct nf_conn *ct;
 578         u16 zone = nf_ct_zone(ignored_conntrack);
 579         unsigned int hash = hash_conntrack(net, zone, tuple);
 580
 581         /* Disable BHs the entire time since we need to disable them at
 582          * least once for the stats anyway.
 583          */
 584         rcu_read_lock_bh();
 585         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 586                 ct = nf_ct_tuplehash_to_ctrack(h);
 587                 if (ct != ignored_conntrack &&
 588                     nf_ct_tuple_equal(tuple, &h->tuple) &&
 589                     nf_ct_zone(ct) == zone) {
 590                         NF_CT_STAT_INC(net, found);
 591                         rcu_read_unlock_bh();
 592                         return 1;
 593                 }
 594                 NF_CT_STAT_INC(net, searched);
 595         }
 596         rcu_read_unlock_bh();
 597
 598         return 0;
 599 }
 600 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 601
 602 #define NF_CT_EVICTION_RANGE    8
 603
 604 /* There's a small race here where we may free a just-assured
 605    connection.  Too bad: we're in trouble anyway. */
 606 static noinline int early_drop(struct net *net, unsigned int hash)
 607 {
 608         /* Use oldest entry, which is roughly LRU */
 609         struct nf_conntrack_tuple_hash *h;
 610         struct nf_conn *ct = NULL, *tmp;
 611         struct hlist_nulls_node *n;
 612         unsigned int i, cnt = 0;
 613         int dropped = 0;
 614
 615         rcu_read_lock();
 616         for (i = 0; i < net->ct.htable_size; i++) {
 617                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 618                                          hnnode) {
 619                         tmp = nf_ct_tuplehash_to_ctrack(h);
 620                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 621                                 ct = tmp;
 622                         cnt++;
 623                 }
 624
 625                 if (ct != NULL) {
 626                         if (likely(!nf_ct_is_dying(ct) &&
 627                                    atomic_inc_not_zero(&ct->ct_general.use)))
 628                                 break;
 629                         else
 630                                 ct = NULL;
 631                 }
 632
 633                 if (cnt >= NF_CT_EVICTION_RANGE)
 634                         break;
 635
 636                 hash = (hash + 1) % net->ct.htable_size;
 637         }
 638         rcu_read_unlock();
 639
 640         if (!ct)
 641                 return dropped;
 642
 643         if (del_timer(&ct->timeout)) {
 644                 death_by_timeout((unsigned long)ct);
 645                 /* Check if we indeed killed this entry. Reliable event
 646                    delivery may have inserted it into the dying list. */
 647                 if (test_bit(IPS_DYING_BIT, &ct->status)) {
 648                         dropped = 1;
 649                         NF_CT_STAT_INC_ATOMIC(net, early_drop);
 650                 }
 651         }
 652         nf_ct_put(ct);
 653         return dropped;
 654 }
 655
 656 void init_nf_conntrack_hash_rnd(void)
 657 {
 658         unsigned int rand;
 659
 660         /*
 661          * Why not initialize nf_conntrack_rnd in a "init()" function ?
 662          * Because there isn't enough entropy when system initializing,
 663          * and we initialize it as late as possible.
 664          */
 665         do {
 666                 get_random_bytes(&rand, sizeof(rand));
 667         } while (!rand);
 668         cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
 669 }
 670
 671 static struct nf_conn *
 672 __nf_conntrack_alloc(struct net *net, u16 zone,
 673                      const struct nf_conntrack_tuple *orig,
 674                      const struct nf_conntrack_tuple *repl,
 675                      gfp_t gfp, u32 hash)
 676 {
 677         struct nf_conn *ct;
 678
 679         if (unlikely(!nf_conntrack_hash_rnd)) {
 680                 init_nf_conntrack_hash_rnd();
 681                 /* recompute the hash as nf_conntrack_hash_rnd is initialized */
 682                 hash = hash_conntrack_raw(orig, zone);
 683         }
 684
 685         /* We don't want any race condition at early drop stage */
 686         atomic_inc(&net->ct.count);
 687
 688         if (nf_conntrack_max &&
 689             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
 690                 if (!early_drop(net, hash_bucket(hash, net))) {
 691                         atomic_dec(&net->ct.count);
 692                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
 693                         return ERR_PTR(-ENOMEM);
 694                 }
 695         }
 696
 697         /*
 698          * Do not use kmem_cache_zalloc(), as this cache uses
 699          * SLAB_DESTROY_BY_RCU.
 700          */
 701         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
 702         if (ct == NULL) {
 703                 atomic_dec(&net->ct.count);
 704                 return ERR_PTR(-ENOMEM);
 705         }
 706         /*
 707          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
 708          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
 709          */
 710         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
 711                offsetof(struct nf_conn, proto) -
 712                offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
 713         spin_lock_init(&ct->lock);
 714         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 715         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
 716         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 717         /* save hash for reusing when confirming */
 718         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
 719         /* Don't set timer yet: wait for confirmation */
 720         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 721         write_pnet(&ct->ct_net, net);
 722 #ifdef CONFIG_NF_CONNTRACK_ZONES
 723         if (zone) {
 724                 struct nf_conntrack_zone *nf_ct_zone;
 725
 726                 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC);
 727                 if (!nf_ct_zone)
 728                         goto out_free;
 729                 nf_ct_zone->id = zone;
 730         }
 731 #endif
 732         /*
 733          * changes to lookup keys must be done before setting refcnt to 1
 734          */
 735         smp_wmb();
 736         atomic_set(&ct->ct_general.use, 1);
 737         return ct;
 738
 739 #ifdef CONFIG_NF_CONNTRACK_ZONES
 740 out_free:
 741         atomic_dec(&net->ct.count);
 742         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 743         return ERR_PTR(-ENOMEM);
 744 #endif
 745 }
 746
 747 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 748                                    const struct nf_conntrack_tuple *orig,
 749                                    const struct nf_conntrack_tuple *repl,
 750                                    gfp_t gfp)
 751 {
 752         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
 753 }
 754 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 755
 756 void nf_conntrack_free(struct nf_conn *ct)
 757 {
 758         struct net *net = nf_ct_net(ct);
 759
 760         nf_ct_ext_destroy(ct);
 761         atomic_dec(&net->ct.count);
 762         nf_ct_ext_free(ct);
 763         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 764 }
 765 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 766
 767 /* Allocate a new conntrack: we return -ENOMEM if classification
 768    failed due to stress.  Otherwise it really is unclassifiable. */
 769 static struct nf_conntrack_tuple_hash *
 770 init_conntrack(struct net *net, struct nf_conn *tmpl,
 771                const struct nf_conntrack_tuple *tuple,
 772                struct nf_conntrack_l3proto *l3proto,
 773                struct nf_conntrack_l4proto *l4proto,
 774                struct sk_buff *skb,
 775                unsigned int dataoff, u32 hash)
 776 {
 777         struct nf_conn *ct;
 778         struct nf_conn_help *help;
 779         struct nf_conntrack_tuple repl_tuple;
 780         struct nf_conntrack_ecache *ecache;
 781         struct nf_conntrack_expect *exp;
 782         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 783         struct nf_conn_timeout *timeout_ext;
 784         unsigned int *timeouts;
 785
 786         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 787                 pr_debug("Can't invert tuple.\n");
 788                 return NULL;
 789         }
 790
 791         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
 792                                   hash);
 793         if (IS_ERR(ct))
 794                 return (struct nf_conntrack_tuple_hash *)ct;
 795
 796         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
 797         if (timeout_ext)
 798                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 799         else
 800                 timeouts = l4proto->get_timeouts(net);
 801
 802         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
 803                 nf_conntrack_free(ct);
 804                 pr_debug("init conntrack: can't track with proto module\n");
 805                 return NULL;
 806         }
 807
 808         if (timeout_ext)
 809                 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC);
 810
 811         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 812         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 813
 814         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
 815         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
 816                                  ecache ? ecache->expmask : 0,
 817                              GFP_ATOMIC);
 818
 819         spin_lock_bh(&nf_conntrack_lock);
 820         exp = nf_ct_find_expectation(net, zone, tuple);
 821         if (exp) {
 822                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 823                          ct, exp);
 824                 /* Welcome, Mr. Bond.  We've been expecting you... */
 825                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
 826                 ct->master = exp->master;
 827                 if (exp->helper) {
 828                         help = nf_ct_helper_ext_add(ct, exp->helper,
 829                                                     GFP_ATOMIC);
 830                         if (help)
 831                                 rcu_assign_pointer(help->helper, exp->helper);
 832                 }
 833
 834 #ifdef CONFIG_NF_CONNTRACK_MARK
 835                 ct->mark = exp->master->mark;
 836 #endif
 837 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 838                 ct->secmark = exp->master->secmark;
 839 #endif
 840                 nf_conntrack_get(&ct->master->ct_general);
 841                 NF_CT_STAT_INC(net, expect_new);
 842         } else {
 843                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
 844                 NF_CT_STAT_INC(net, new);
 845         }
 846
 847         /* Overload tuple linked list to put us in unconfirmed list. */
 848         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 849                        &net->ct.unconfirmed);
 850
 851         spin_unlock_bh(&nf_conntrack_lock);
 852
 853         if (exp) {
 854                 if (exp->expectfn)
 855                         exp->expectfn(ct, exp);
 856                 nf_ct_expect_put(exp);
 857         }
 858
 859         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
 860 }
 861
 862 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 863 static inline struct nf_conn *
 864 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
 865                   struct sk_buff *skb,
 866                   unsigned int dataoff,
 867                   u_int16_t l3num,
 868                   u_int8_t protonum,
 869                   struct nf_conntrack_l3proto *l3proto,
 870                   struct nf_conntrack_l4proto *l4proto,
 871                   int *set_reply,
 872                   enum ip_conntrack_info *ctinfo)
 873 {
 874         struct nf_conntrack_tuple tuple;
 875         struct nf_conntrack_tuple_hash *h;
 876         struct nf_conn *ct;
 877         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 878         u32 hash;
 879
 880         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 881                              dataoff, l3num, protonum, &tuple, l3proto,
 882                              l4proto)) {
 883                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 884                 return NULL;
 885         }
 886
 887         /* look for tuple match */
 888         hash = hash_conntrack_raw(&tuple, zone);
 889         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
 890         if (!h) {
 891                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
 892                                    skb, dataoff, hash);
 893                 if (!h)
 894                         return NULL;
 895                 if (IS_ERR(h))
 896                         return (void *)h;
 897         }
 898         ct = nf_ct_tuplehash_to_ctrack(h);
 899
 900         /* It exists; we have (non-exclusive) reference. */
 901         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 902                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
 903                 /* Please set reply bit if this packet OK */
 904                 *set_reply = 1;
 905         } else {
 906                 /* Once we've had two way comms, always ESTABLISHED. */
 907                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 908                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 909                         *ctinfo = IP_CT_ESTABLISHED;
 910                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 911                         pr_debug("nf_conntrack_in: related packet for %p\n",
 912                                  ct);
 913                         *ctinfo = IP_CT_RELATED;
 914                 } else {
 915                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 916                         *ctinfo = IP_CT_NEW;
 917                 }
 918                 *set_reply = 0;
 919         }
 920         skb->nfct = &ct->ct_general;
 921         skb->nfctinfo = *ctinfo;
 922         return ct;
 923 }
 924
 925 unsigned int
 926 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 927                 struct sk_buff *skb)
 928 {
 929         struct nf_conn *ct, *tmpl = NULL;
 930         enum ip_conntrack_info ctinfo;
 931         struct nf_conntrack_l3proto *l3proto;
 932         struct nf_conntrack_l4proto *l4proto;
 933         unsigned int *timeouts;
 934         unsigned int dataoff;
 935         u_int8_t protonum;
 936         int set_reply = 0;
 937         int ret;
 938
 939         if (skb->nfct) {
 940                 /* Previously seen (loopback or untracked)?  Ignore. */
 941                 tmpl = (struct nf_conn *)skb->nfct;
 942                 if (!nf_ct_is_template(tmpl)) {
 943                         NF_CT_STAT_INC_ATOMIC(net, ignore);
 944                         return NF_ACCEPT;
 945                 }
 946                 skb->nfct = NULL;
 947         }
 948
 949         /* rcu_read_lock()ed by nf_hook_slow */
 950         l3proto = __nf_ct_l3proto_find(pf);
 951         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 952                                    &dataoff, &protonum);
 953         if (ret <= 0) {
 954                 pr_debug("not prepared to track yet or error occurred\n");
 955                 NF_CT_STAT_INC_ATOMIC(net, error);
 956                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 957                 ret = -ret;
 958                 goto out;
 959         }
 960
 961         l4proto = __nf_ct_l4proto_find(pf, protonum);
 962
 963         /* It may be an special packet, error, unclean...
 964          * inverse of the return code tells to the netfilter
 965          * core what to do with the packet. */
 966         if (l4proto->error != NULL) {
 967                 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
 968                                      pf, hooknum);
 969                 if (ret <= 0) {
 970                         NF_CT_STAT_INC_ATOMIC(net, error);
 971                         NF_CT_STAT_INC_ATOMIC(net, invalid);
 972                         ret = -ret;
 973                         goto out;
 974                 }
 975                 /* ICMP[v6] protocol trackers may assign one conntrack. */
 976                 if (skb->nfct)
 977                         goto out;
 978         }
 979
 980         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
 981                                l3proto, l4proto, &set_reply, &ctinfo);
 982         if (!ct) {
 983                 /* Not valid part of a connection */
 984                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 985                 ret = NF_ACCEPT;
 986                 goto out;
 987         }
 988
 989         if (IS_ERR(ct)) {
 990                 /* Too stressed to deal. */
 991                 NF_CT_STAT_INC_ATOMIC(net, drop);
 992                 ret = NF_DROP;
 993                 goto out;
 994         }
 995
 996         NF_CT_ASSERT(skb->nfct);
 997
 998         /* Decide what timeout policy we want to apply to this flow. */
 999         timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1000
1001         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1002         if (ret <= 0) {
1003                 /* Invalid: inverse of the return code tells
1004                  * the netfilter core what to do */
1005                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1006                 nf_conntrack_put(skb->nfct);
1007                 skb->nfct = NULL;
1008                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1009                 if (ret == -NF_DROP)
1010                         NF_CT_STAT_INC_ATOMIC(net, drop);
1011                 ret = -ret;
1012                 goto out;
1013         }
1014
1015         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1016                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1017 out:
1018         if (tmpl) {
1019                 /* Special case: we have to repeat this hook, assign the
1020                  * template again to this packet. We assume that this packet
1021                  * has no conntrack assigned. This is used by nf_ct_tcp. */
1022                 if (ret == NF_REPEAT)
1023                         skb->nfct = (struct nf_conntrack *)tmpl;
1024                 else
1025                         nf_ct_put(tmpl);
1026         }
1027
1028         return ret;
1029 }
1030 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1031
1032 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1033                           const struct nf_conntrack_tuple *orig)
1034 {
1035         bool ret;
1036
1037         rcu_read_lock();
1038         ret = nf_ct_invert_tuple(inverse, orig,
1039                                  __nf_ct_l3proto_find(orig->src.l3num),
1040                                  __nf_ct_l4proto_find(orig->src.l3num,
1041                                                       orig->dst.protonum));
1042         rcu_read_unlock();
1043         return ret;
1044 }
1045 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1046
1047 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1048    implicitly racy: see __nf_conntrack_confirm */
1049 void nf_conntrack_alter_reply(struct nf_conn *ct,
1050                               const struct nf_conntrack_tuple *newreply)
1051 {
1052         struct nf_conn_help *help = nfct_help(ct);
1053
1054         /* Should be unconfirmed, so not in hash table yet */
1055         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1056
1057         pr_debug("Altering reply tuple of %p to ", ct);
1058         nf_ct_dump_tuple(newreply);
1059
1060         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1061         if (ct->master || (help && !hlist_empty(&help->expectations)))
1062                 return;
1063
1064         rcu_read_lock();
1065         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1066         rcu_read_unlock();
1067 }
1068 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1069
1070 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1071 void __nf_ct_refresh_acct(struct nf_conn *ct,
1072                           enum ip_conntrack_info ctinfo,
1073                           const struct sk_buff *skb,
1074                           unsigned long extra_jiffies,
1075                           int do_acct)
1076 {
1077         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1078         NF_CT_ASSERT(skb);
1079
1080         /* Only update if this is not a fixed timeout */
1081         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1082                 goto acct;
1083
1084         /* If not in hash table, timer will not be active yet */
1085         if (!nf_ct_is_confirmed(ct)) {
1086                 ct->timeout.expires = extra_jiffies;
1087         } else {
1088                 unsigned long newtime = jiffies + extra_jiffies;
1089
1090                 /* Only update the timeout if the new timeout is at least
1091                    HZ jiffies from the old timeout. Need del_timer for race
1092                    avoidance (may already be dying). */
1093                 if (newtime - ct->timeout.expires >= HZ)
1094                         mod_timer_pending(&ct->timeout, newtime);
1095         }
1096
1097 acct:
1098         if (do_acct) {
1099                 struct nf_conn_counter *acct;
1100
1101                 acct = nf_conn_acct_find(ct);
1102                 if (acct) {
1103                         atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1104                         atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes);
1105                 }
1106         }
1107 }
1108 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1109
1110 bool __nf_ct_kill_acct(struct nf_conn *ct,
1111                        enum ip_conntrack_info ctinfo,
1112                        const struct sk_buff *skb,
1113                        int do_acct)
1114 {
1115         if (do_acct) {
1116                 struct nf_conn_counter *acct;
1117
1118                 acct = nf_conn_acct_find(ct);
1119                 if (acct) {
1120                         atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1121                         atomic64_add(skb->len - skb_network_offset(skb),
1122                                      &acct[CTINFO2DIR(ctinfo)].bytes);
1123                 }
1124         }
1125
1126         if (del_timer(&ct->timeout)) {
1127                 ct->timeout.function((unsigned long)ct);
1128                 return true;
1129         }
1130         return false;
1131 }
1132 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1133
1134 #ifdef CONFIG_NF_CONNTRACK_ZONES
1135 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1136         .len    = sizeof(struct nf_conntrack_zone),
1137         .align  = __alignof__(struct nf_conntrack_zone),
1138         .id     = NF_CT_EXT_ZONE,
1139 };
1140 #endif
1141
1142 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1143
1144 #include <linux/netfilter/nfnetlink.h>
1145 #include <linux/netfilter/nfnetlink_conntrack.h>
1146 #include <linux/mutex.h>
1147
1148 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1149  * in ip_conntrack_core, since we don't want the protocols to autoload
1150  * or depend on ctnetlink */
1151 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1152                                const struct nf_conntrack_tuple *tuple)
1153 {
1154         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1155             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1156                 goto nla_put_failure;
1157         return 0;
1158
1159 nla_put_failure:
1160         return -1;
1161 }
1162 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1163
1164 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1165         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1166         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1167 };
1168 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1169
1170 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1171                                struct nf_conntrack_tuple *t)
1172 {
1173         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1174                 return -EINVAL;
1175
1176         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1177         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1178
1179         return 0;
1180 }
1181 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1182
1183 int nf_ct_port_nlattr_tuple_size(void)
1184 {
1185         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1186 }
1187 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1188 #endif
1189
1190 /* Used by ipt_REJECT and ip6t_REJECT. */
1191 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1192 {
1193         struct nf_conn *ct;
1194         enum ip_conntrack_info ctinfo;
1195
1196         /* This ICMP is in reverse direction to the packet which caused it */
1197         ct = nf_ct_get(skb, &ctinfo);
1198         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1199                 ctinfo = IP_CT_RELATED_REPLY;
1200         else
1201                 ctinfo = IP_CT_RELATED;
1202
1203         /* Attach to new skbuff, and increment count */
1204         nskb->nfct = &ct->ct_general;
1205         nskb->nfctinfo = ctinfo;
1206         nf_conntrack_get(nskb->nfct);
1207 }
1208
1209 /* Bring out ya dead! */
1210 static struct nf_conn *
1211 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1212                 void *data, unsigned int *bucket)
1213 {
1214         struct nf_conntrack_tuple_hash *h;
1215         struct nf_conn *ct;
1216         struct hlist_nulls_node *n;
1217
1218         spin_lock_bh(&nf_conntrack_lock);
1219         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1220                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1221                         ct = nf_ct_tuplehash_to_ctrack(h);
1222                         if (iter(ct, data))
1223                                 goto found;
1224                 }
1225         }
1226         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1227                 ct = nf_ct_tuplehash_to_ctrack(h);
1228                 if (iter(ct, data))
1229                         set_bit(IPS_DYING_BIT, &ct->status);
1230         }
1231         spin_unlock_bh(&nf_conntrack_lock);
1232         return NULL;
1233 found:
1234         atomic_inc(&ct->ct_general.use);
1235         spin_unlock_bh(&nf_conntrack_lock);
1236         return ct;
1237 }
1238
1239 void nf_ct_iterate_cleanup(struct net *net,
1240                            int (*iter)(struct nf_conn *i, void *data),
1241                            void *data)
1242 {
1243         struct nf_conn *ct;
1244         unsigned int bucket = 0;
1245
1246         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1247                 /* Time to push up daises... */
1248                 if (del_timer(&ct->timeout))
1249                         death_by_timeout((unsigned long)ct);
1250                 /* ... else the timer will get him soon. */
1251
1252                 nf_ct_put(ct);
1253         }
1254 }
1255 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1256
1257 struct __nf_ct_flush_report {
1258         u32 pid;
1259         int report;
1260 };
1261
1262 static int kill_report(struct nf_conn *i, void *data)
1263 {
1264         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1265         struct nf_conn_tstamp *tstamp;
1266
1267         tstamp = nf_conn_tstamp_find(i);
1268         if (tstamp && tstamp->stop == 0)
1269                 tstamp->stop = ktime_to_ns(ktime_get_real());
1270
1271         /* If we fail to deliver the event, death_by_timeout() will retry */
1272         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1273                                       fr->pid, fr->report) < 0)
1274                 return 1;
1275
1276         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1277         set_bit(IPS_DYING_BIT, &i->status);
1278         return 1;
1279 }
1280
1281 static int kill_all(struct nf_conn *i, void *data)
1282 {
1283         return 1;
1284 }
1285
1286 void nf_ct_free_hashtable(void *hash, unsigned int size)
1287 {
1288         if (is_vmalloc_addr(hash))
1289                 vfree(hash);
1290         else
1291                 free_pages((unsigned long)hash,
1292                            get_order(sizeof(struct hlist_head) * size));
1293 }
1294 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1295
1296 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1297 {
1298         struct __nf_ct_flush_report fr = {
1299                 .pid    = pid,
1300                 .report = report,
1301         };
1302         nf_ct_iterate_cleanup(net, kill_report, &fr);
1303 }
1304 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1305
1306 static void nf_ct_release_dying_list(struct net *net)
1307 {
1308         struct nf_conntrack_tuple_hash *h;
1309         struct nf_conn *ct;
1310         struct hlist_nulls_node *n;
1311
1312         spin_lock_bh(&nf_conntrack_lock);
1313         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1314                 ct = nf_ct_tuplehash_to_ctrack(h);
1315                 /* never fails to remove them, no listeners at this point */
1316                 nf_ct_kill(ct);
1317         }
1318         spin_unlock_bh(&nf_conntrack_lock);
1319 }
1320
1321 static int untrack_refs(void)
1322 {
1323         int cnt = 0, cpu;
1324
1325         for_each_possible_cpu(cpu) {
1326                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1327
1328                 cnt += atomic_read(&ct->ct_general.use) - 1;
1329         }
1330         return cnt;
1331 }
1332
1333 static void nf_conntrack_cleanup_init_net(void)
1334 {
1335         while (untrack_refs() > 0)
1336                 schedule();
1337
1338 #ifdef CONFIG_NF_CONNTRACK_ZONES
1339         nf_ct_extend_unregister(&nf_ct_zone_extend);
1340 #endif
1341 }
1342
1343 static void nf_conntrack_cleanup_net(struct net *net)
1344 {
1345  i_see_dead_people:
1346         nf_ct_iterate_cleanup(net, kill_all, NULL);
1347         nf_ct_release_dying_list(net);
1348         if (atomic_read(&net->ct.count) != 0) {
1349                 schedule();
1350                 goto i_see_dead_people;
1351         }
1352
1353         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1354         nf_conntrack_helper_fini(net);
1355         nf_conntrack_timeout_fini(net);
1356         nf_conntrack_ecache_fini(net);
1357         nf_conntrack_tstamp_fini(net);
1358         nf_conntrack_acct_fini(net);
1359         nf_conntrack_expect_fini(net);
1360         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1361         kfree(net->ct.slabname);
1362         free_percpu(net->ct.stat);
1363 }
1364
1365 /* Mishearing the voices in his head, our hero wonders how he's
1366    supposed to kill the mall. */
1367 void nf_conntrack_cleanup(struct net *net)
1368 {
1369         if (net_eq(net, &init_net))
1370                 RCU_INIT_POINTER(ip_ct_attach, NULL);
1371
1372         /* This makes sure all current packets have passed through
1373            netfilter framework.  Roll on, two-stage module
1374            delete... */
1375         synchronize_net();
1376         nf_conntrack_proto_fini(net);
1377         nf_conntrack_cleanup_net(net);
1378
1379         if (net_eq(net, &init_net)) {
1380                 RCU_INIT_POINTER(nf_ct_destroy, NULL);
1381                 nf_conntrack_cleanup_init_net();
1382         }
1383 }
1384
1385 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1386 {
1387         struct hlist_nulls_head *hash;
1388         unsigned int nr_slots, i;
1389         size_t sz;
1390
1391         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1392         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1393         sz = nr_slots * sizeof(struct hlist_nulls_head);
1394         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1395                                         get_order(sz));
1396         if (!hash) {
1397                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1398                 hash = vzalloc(sz);
1399         }
1400
1401         if (hash && nulls)
1402                 for (i = 0; i < nr_slots; i++)
1403                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1404
1405         return hash;
1406 }
1407 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1408
1409 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1410 {
1411         int i, bucket;
1412         unsigned int hashsize, old_size;
1413         struct hlist_nulls_head *hash, *old_hash;
1414         struct nf_conntrack_tuple_hash *h;
1415         struct nf_conn *ct;
1416
1417         if (current->nsproxy->net_ns != &init_net)
1418                 return -EOPNOTSUPP;
1419
1420         /* On boot, we can set this without any fancy locking. */
1421         if (!nf_conntrack_htable_size)
1422                 return param_set_uint(val, kp);
1423
1424         hashsize = simple_strtoul(val, NULL, 0);
1425         if (!hashsize)
1426                 return -EINVAL;
1427
1428         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1429         if (!hash)
1430                 return -ENOMEM;
1431
1432         /* Lookups in the old hash might happen in parallel, which means we
1433          * might get false negatives during connection lookup. New connections
1434          * created because of a false negative won't make it into the hash
1435          * though since that required taking the lock.
1436          */
1437         spin_lock_bh(&nf_conntrack_lock);
1438         for (i = 0; i < init_net.ct.htable_size; i++) {
1439                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1440                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1441                                         struct nf_conntrack_tuple_hash, hnnode);
1442                         ct = nf_ct_tuplehash_to_ctrack(h);
1443                         hlist_nulls_del_rcu(&h->hnnode);
1444                         bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct),
1445                                                   hashsize);
1446                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1447                 }
1448         }
1449         old_size = init_net.ct.htable_size;
1450         old_hash = init_net.ct.hash;
1451
1452         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1453         init_net.ct.hash = hash;
1454         spin_unlock_bh(&nf_conntrack_lock);
1455
1456         nf_ct_free_hashtable(old_hash, old_size);
1457         return 0;
1458 }
1459 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1460
1461 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1462                   &nf_conntrack_htable_size, 0600);
1463
1464 void nf_ct_untracked_status_or(unsigned long bits)
1465 {
1466         int cpu;
1467
1468         for_each_possible_cpu(cpu)
1469                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1470 }
1471 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1472
1473 static int nf_conntrack_init_init_net(void)
1474 {
1475         int max_factor = 8;
1476         int ret, cpu;
1477
1478         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1479          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1480         if (!nf_conntrack_htable_size) {
1481                 nf_conntrack_htable_size
1482                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1483                            / sizeof(struct hlist_head));
1484                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1485                         nf_conntrack_htable_size = 16384;
1486                 if (nf_conntrack_htable_size < 32)
1487                         nf_conntrack_htable_size = 32;
1488
1489                 /* Use a max. factor of four by default to get the same max as
1490                  * with the old struct list_heads. When a table size is given
1491                  * we use the old value of 8 to avoid reducing the max.
1492                  * entries. */
1493                 max_factor = 4;
1494         }
1495         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1496
1497         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1498                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1499                nf_conntrack_max);
1500 #ifdef CONFIG_NF_CONNTRACK_ZONES
1501         ret = nf_ct_extend_register(&nf_ct_zone_extend);
1502         if (ret < 0)
1503                 goto err_extend;
1504 #endif
1505         /* Set up fake conntrack: to never be deleted, not in any hashes */
1506         for_each_possible_cpu(cpu) {
1507                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1508                 write_pnet(&ct->ct_net, &init_net);
1509                 atomic_set(&ct->ct_general.use, 1);
1510         }
1511         /*  - and look it like as a confirmed connection */
1512         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1513         return 0;
1514
1515 #ifdef CONFIG_NF_CONNTRACK_ZONES
1516 err_extend:
1517 #endif
1518         return ret;
1519 }
1520
1521 /*
1522  * We need to use special "null" values, not used in hash table
1523  */
1524 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1525 #define DYING_NULLS_VAL         ((1<<30)+1)
1526
1527 static int nf_conntrack_init_net(struct net *net)
1528 {
1529         int ret;
1530
1531         atomic_set(&net->ct.count, 0);
1532         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1533         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1534         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1535         if (!net->ct.stat) {
1536                 ret = -ENOMEM;
1537                 goto err_stat;
1538         }
1539
1540         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1541         if (!net->ct.slabname) {
1542                 ret = -ENOMEM;
1543                 goto err_slabname;
1544         }
1545
1546         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1547                                                         sizeof(struct nf_conn), 0,
1548                                                         SLAB_DESTROY_BY_RCU, NULL);
1549         if (!net->ct.nf_conntrack_cachep) {
1550                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1551                 ret = -ENOMEM;
1552                 goto err_cache;
1553         }
1554
1555         net->ct.htable_size = nf_conntrack_htable_size;
1556         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1557         if (!net->ct.hash) {
1558                 ret = -ENOMEM;
1559                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1560                 goto err_hash;
1561         }
1562         ret = nf_conntrack_expect_init(net);
1563         if (ret < 0)
1564                 goto err_expect;
1565         ret = nf_conntrack_acct_init(net);
1566         if (ret < 0)
1567                 goto err_acct;
1568         ret = nf_conntrack_tstamp_init(net);
1569         if (ret < 0)
1570                 goto err_tstamp;
1571         ret = nf_conntrack_ecache_init(net);
1572         if (ret < 0)
1573                 goto err_ecache;
1574         ret = nf_conntrack_timeout_init(net);
1575         if (ret < 0)
1576                 goto err_timeout;
1577         ret = nf_conntrack_helper_init(net);
1578         if (ret < 0)
1579                 goto err_helper;
1580         return 0;
1581 err_helper:
1582         nf_conntrack_timeout_fini(net);
1583 err_timeout:
1584         nf_conntrack_ecache_fini(net);
1585 err_ecache:
1586         nf_conntrack_tstamp_fini(net);
1587 err_tstamp:
1588         nf_conntrack_acct_fini(net);
1589 err_acct:
1590         nf_conntrack_expect_fini(net);
1591 err_expect:
1592         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1593 err_hash:
1594         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1595 err_cache:
1596         kfree(net->ct.slabname);
1597 err_slabname:
1598         free_percpu(net->ct.stat);
1599 err_stat:
1600         return ret;
1601 }
1602
1603 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1604                         enum ip_conntrack_dir dir,
1605                         u32 seq);
1606 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1607
1608 int nf_conntrack_init(struct net *net)
1609 {
1610         int ret;
1611
1612         if (net_eq(net, &init_net)) {
1613                 ret = nf_conntrack_init_init_net();
1614                 if (ret < 0)
1615                         goto out_init_net;
1616         }
1617         ret = nf_conntrack_proto_init(net);
1618         if (ret < 0)
1619                 goto out_proto;
1620         ret = nf_conntrack_init_net(net);
1621         if (ret < 0)
1622                 goto out_net;
1623
1624         if (net_eq(net, &init_net)) {
1625                 /* For use by REJECT target */
1626                 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1627                 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1628
1629                 /* Howto get NAT offsets */
1630                 RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
1631         }
1632         return 0;
1633
1634 out_net:
1635         nf_conntrack_proto_fini(net);
1636 out_proto:
1637         if (net_eq(net, &init_net))
1638                 nf_conntrack_cleanup_init_net();
1639 out_init_net:
1640         return ret;
1641 }