Pileus Git - ~andy/linux/blob - net/netfilter/nf_conntrack_core.c

   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  * (C) 2005-2012 Patrick McHardy <kaber@trash.net>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/types.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/stddef.h>
  23 #include <linux/slab.h>
  24 #include <linux/random.h>
  25 #include <linux/jhash.h>
  26 #include <linux/err.h>
  27 #include <linux/percpu.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/notifier.h>
  30 #include <linux/kernel.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/socket.h>
  33 #include <linux/mm.h>
  34 #include <linux/nsproxy.h>
  35 #include <linux/rculist_nulls.h>
  36
  37 #include <net/netfilter/nf_conntrack.h>
  38 #include <net/netfilter/nf_conntrack_l3proto.h>
  39 #include <net/netfilter/nf_conntrack_l4proto.h>
  40 #include <net/netfilter/nf_conntrack_expect.h>
  41 #include <net/netfilter/nf_conntrack_helper.h>
  42 #include <net/netfilter/nf_conntrack_seqadj.h>
  43 #include <net/netfilter/nf_conntrack_core.h>
  44 #include <net/netfilter/nf_conntrack_extend.h>
  45 #include <net/netfilter/nf_conntrack_acct.h>
  46 #include <net/netfilter/nf_conntrack_ecache.h>
  47 #include <net/netfilter/nf_conntrack_zones.h>
  48 #include <net/netfilter/nf_conntrack_timestamp.h>
  49 #include <net/netfilter/nf_conntrack_timeout.h>
  50 #include <net/netfilter/nf_conntrack_labels.h>
  51 #include <net/netfilter/nf_conntrack_synproxy.h>
  52 #include <net/netfilter/nf_nat.h>
  53 #include <net/netfilter/nf_nat_core.h>
  54 #include <net/netfilter/nf_nat_helper.h>
  55
  56 #define NF_CONNTRACK_VERSION    "0.5.0"
  57
  58 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
  59                                       enum nf_nat_manip_type manip,
  60                                       const struct nlattr *attr) __read_mostly;
  61 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
  62
  63 int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
  64                               struct nf_conn *ct,
  65                               enum ip_conntrack_info ctinfo,
  66                               unsigned int protoff);
  67 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
  68
  69 DEFINE_SPINLOCK(nf_conntrack_lock);
  70 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  71
  72 unsigned int nf_conntrack_htable_size __read_mostly;
  73 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  74
  75 unsigned int nf_conntrack_max __read_mostly;
  76 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  77
  78 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
  79 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
  80
  81 unsigned int nf_conntrack_hash_rnd __read_mostly;
  82 EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd);
  83
  84 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone)
  85 {
  86         unsigned int n;
  87
  88         /* The direction must be ignored, so we hash everything up to the
  89          * destination ports (which is a multiple of 4) and treat the last
  90          * three bytes manually.
  91          */
  92         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
  93         return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^
  94                       (((__force __u16)tuple->dst.u.all << 16) |
  95                       tuple->dst.protonum));
  96 }
  97
  98 static u32 __hash_bucket(u32 hash, unsigned int size)
  99 {
 100         return ((u64)hash * size) >> 32;
 101 }
 102
 103 static u32 hash_bucket(u32 hash, const struct net *net)
 104 {
 105         return __hash_bucket(hash, net->ct.htable_size);
 106 }
 107
 108 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 109                                   u16 zone, unsigned int size)
 110 {
 111         return __hash_bucket(hash_conntrack_raw(tuple, zone), size);
 112 }
 113
 114 static inline u_int32_t hash_conntrack(const struct net *net, u16 zone,
 115                                        const struct nf_conntrack_tuple *tuple)
 116 {
 117         return __hash_conntrack(tuple, zone, net->ct.htable_size);
 118 }
 119
 120 bool
 121 nf_ct_get_tuple(const struct sk_buff *skb,
 122                 unsigned int nhoff,
 123                 unsigned int dataoff,
 124                 u_int16_t l3num,
 125                 u_int8_t protonum,
 126                 struct nf_conntrack_tuple *tuple,
 127                 const struct nf_conntrack_l3proto *l3proto,
 128                 const struct nf_conntrack_l4proto *l4proto)
 129 {
 130         memset(tuple, 0, sizeof(*tuple));
 131
 132         tuple->src.l3num = l3num;
 133         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 134                 return false;
 135
 136         tuple->dst.protonum = protonum;
 137         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 138
 139         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 140 }
 141 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 142
 143 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 144                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
 145 {
 146         struct nf_conntrack_l3proto *l3proto;
 147         struct nf_conntrack_l4proto *l4proto;
 148         unsigned int protoff;
 149         u_int8_t protonum;
 150         int ret;
 151
 152         rcu_read_lock();
 153
 154         l3proto = __nf_ct_l3proto_find(l3num);
 155         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 156         if (ret != NF_ACCEPT) {
 157                 rcu_read_unlock();
 158                 return false;
 159         }
 160
 161         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 162
 163         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 164                               l3proto, l4proto);
 165
 166         rcu_read_unlock();
 167         return ret;
 168 }
 169 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 170
 171 bool
 172 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 173                    const struct nf_conntrack_tuple *orig,
 174                    const struct nf_conntrack_l3proto *l3proto,
 175                    const struct nf_conntrack_l4proto *l4proto)
 176 {
 177         memset(inverse, 0, sizeof(*inverse));
 178
 179         inverse->src.l3num = orig->src.l3num;
 180         if (l3proto->invert_tuple(inverse, orig) == 0)
 181                 return false;
 182
 183         inverse->dst.dir = !orig->dst.dir;
 184
 185         inverse->dst.protonum = orig->dst.protonum;
 186         return l4proto->invert_tuple(inverse, orig);
 187 }
 188 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 189
 190 static void
 191 clean_from_lists(struct nf_conn *ct)
 192 {
 193         pr_debug("clean_from_lists(%p)\n", ct);
 194         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 195         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 196
 197         /* Destroy all pending expectations */
 198         nf_ct_remove_expectations(ct);
 199 }
 200
 201 static void
 202 destroy_conntrack(struct nf_conntrack *nfct)
 203 {
 204         struct nf_conn *ct = (struct nf_conn *)nfct;
 205         struct net *net = nf_ct_net(ct);
 206         struct nf_conntrack_l4proto *l4proto;
 207
 208         pr_debug("destroy_conntrack(%p)\n", ct);
 209         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 210         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 211
 212         /* To make sure we don't get any weird locking issues here:
 213          * destroy_conntrack() MUST NOT be called with a write lock
 214          * to nf_conntrack_lock!!! -HW */
 215         rcu_read_lock();
 216         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 217         if (l4proto && l4proto->destroy)
 218                 l4proto->destroy(ct);
 219
 220         rcu_read_unlock();
 221
 222         spin_lock_bh(&nf_conntrack_lock);
 223         /* Expectations will have been removed in clean_from_lists,
 224          * except TFTP can create an expectation on the first packet,
 225          * before connection is in the list, so we need to clean here,
 226          * too. */
 227         nf_ct_remove_expectations(ct);
 228
 229         /* We overload first tuple to link into unconfirmed or dying list.*/
 230         BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 231         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 232
 233         NF_CT_STAT_INC(net, delete);
 234         spin_unlock_bh(&nf_conntrack_lock);
 235
 236         if (ct->master)
 237                 nf_ct_put(ct->master);
 238
 239         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 240         nf_conntrack_free(ct);
 241 }
 242
 243 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 244 {
 245         struct net *net = nf_ct_net(ct);
 246
 247         nf_ct_helper_destroy(ct);
 248         spin_lock_bh(&nf_conntrack_lock);
 249         /* Inside lock so preempt is disabled on module removal path.
 250          * Otherwise we can get spurious warnings. */
 251         NF_CT_STAT_INC(net, delete_list);
 252         clean_from_lists(ct);
 253         /* add this conntrack to the dying list */
 254         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 255                              &net->ct.dying);
 256         spin_unlock_bh(&nf_conntrack_lock);
 257 }
 258
 259 static void death_by_event(unsigned long ul_conntrack)
 260 {
 261         struct nf_conn *ct = (void *)ul_conntrack;
 262         struct net *net = nf_ct_net(ct);
 263         struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct);
 264
 265         BUG_ON(ecache == NULL);
 266
 267         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
 268                 /* bad luck, let's retry again */
 269                 ecache->timeout.expires = jiffies +
 270                         (prandom_u32() % net->ct.sysctl_events_retry_timeout);
 271                 add_timer(&ecache->timeout);
 272                 return;
 273         }
 274         /* we've got the event delivered, now it's dying */
 275         set_bit(IPS_DYING_BIT, &ct->status);
 276         nf_ct_put(ct);
 277 }
 278
 279 static void nf_ct_dying_timeout(struct nf_conn *ct)
 280 {
 281         struct net *net = nf_ct_net(ct);
 282         struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct);
 283
 284         BUG_ON(ecache == NULL);
 285
 286         /* set a new timer to retry event delivery */
 287         setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct);
 288         ecache->timeout.expires = jiffies +
 289                 (prandom_u32() % net->ct.sysctl_events_retry_timeout);
 290         add_timer(&ecache->timeout);
 291 }
 292
 293 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 294 {
 295         struct nf_conn_tstamp *tstamp;
 296
 297         tstamp = nf_conn_tstamp_find(ct);
 298         if (tstamp && tstamp->stop == 0)
 299                 tstamp->stop = ktime_to_ns(ktime_get_real());
 300
 301         if (!nf_ct_is_dying(ct) &&
 302             unlikely(nf_conntrack_event_report(IPCT_DESTROY, ct,
 303             portid, report) < 0)) {
 304                 /* destroy event was not delivered */
 305                 nf_ct_delete_from_lists(ct);
 306                 nf_ct_dying_timeout(ct);
 307                 return false;
 308         }
 309         set_bit(IPS_DYING_BIT, &ct->status);
 310         nf_ct_delete_from_lists(ct);
 311         nf_ct_put(ct);
 312         return true;
 313 }
 314 EXPORT_SYMBOL_GPL(nf_ct_delete);
 315
 316 static void death_by_timeout(unsigned long ul_conntrack)
 317 {
 318         nf_ct_delete((struct nf_conn *)ul_conntrack, 0, 0);
 319 }
 320
 321 /*
 322  * Warning :
 323  * - Caller must take a reference on returned object
 324  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 325  * OR
 326  * - Caller must lock nf_conntrack_lock before calling this function
 327  */
 328 static struct nf_conntrack_tuple_hash *
 329 ____nf_conntrack_find(struct net *net, u16 zone,
 330                       const struct nf_conntrack_tuple *tuple, u32 hash)
 331 {
 332         struct nf_conntrack_tuple_hash *h;
 333         struct hlist_nulls_node *n;
 334         unsigned int bucket = hash_bucket(hash, net);
 335
 336         /* Disable BHs the entire time since we normally need to disable them
 337          * at least once for the stats anyway.
 338          */
 339         local_bh_disable();
 340 begin:
 341         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
 342                 if (nf_ct_tuple_equal(tuple, &h->tuple) &&
 343                     nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) {
 344                         NF_CT_STAT_INC(net, found);
 345                         local_bh_enable();
 346                         return h;
 347                 }
 348                 NF_CT_STAT_INC(net, searched);
 349         }
 350         /*
 351          * if the nulls value we got at the end of this lookup is
 352          * not the expected one, we must restart lookup.
 353          * We probably met an item that was moved to another chain.
 354          */
 355         if (get_nulls_value(n) != bucket) {
 356                 NF_CT_STAT_INC(net, search_restart);
 357                 goto begin;
 358         }
 359         local_bh_enable();
 360
 361         return NULL;
 362 }
 363
 364 struct nf_conntrack_tuple_hash *
 365 __nf_conntrack_find(struct net *net, u16 zone,
 366                     const struct nf_conntrack_tuple *tuple)
 367 {
 368         return ____nf_conntrack_find(net, zone, tuple,
 369                                      hash_conntrack_raw(tuple, zone));
 370 }
 371 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 372
 373 /* Find a connection corresponding to a tuple. */
 374 static struct nf_conntrack_tuple_hash *
 375 __nf_conntrack_find_get(struct net *net, u16 zone,
 376                         const struct nf_conntrack_tuple *tuple, u32 hash)
 377 {
 378         struct nf_conntrack_tuple_hash *h;
 379         struct nf_conn *ct;
 380
 381         rcu_read_lock();
 382 begin:
 383         h = ____nf_conntrack_find(net, zone, tuple, hash);
 384         if (h) {
 385                 ct = nf_ct_tuplehash_to_ctrack(h);
 386                 if (unlikely(nf_ct_is_dying(ct) ||
 387                              !atomic_inc_not_zero(&ct->ct_general.use)))
 388                         h = NULL;
 389                 else {
 390                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) ||
 391                                      nf_ct_zone(ct) != zone)) {
 392                                 nf_ct_put(ct);
 393                                 goto begin;
 394                         }
 395                 }
 396         }
 397         rcu_read_unlock();
 398
 399         return h;
 400 }
 401
 402 struct nf_conntrack_tuple_hash *
 403 nf_conntrack_find_get(struct net *net, u16 zone,
 404                       const struct nf_conntrack_tuple *tuple)
 405 {
 406         return __nf_conntrack_find_get(net, zone, tuple,
 407                                        hash_conntrack_raw(tuple, zone));
 408 }
 409 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 410
 411 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 412                                        unsigned int hash,
 413                                        unsigned int repl_hash)
 414 {
 415         struct net *net = nf_ct_net(ct);
 416
 417         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 418                            &net->ct.hash[hash]);
 419         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 420                            &net->ct.hash[repl_hash]);
 421 }
 422
 423 int
 424 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 425 {
 426         struct net *net = nf_ct_net(ct);
 427         unsigned int hash, repl_hash;
 428         struct nf_conntrack_tuple_hash *h;
 429         struct hlist_nulls_node *n;
 430         u16 zone;
 431
 432         zone = nf_ct_zone(ct);
 433         hash = hash_conntrack(net, zone,
 434                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 435         repl_hash = hash_conntrack(net, zone,
 436                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 437
 438         spin_lock_bh(&nf_conntrack_lock);
 439
 440         /* See if there's one in the list already, including reverse */
 441         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 442                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 443                                       &h->tuple) &&
 444                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 445                         goto out;
 446         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 447                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 448                                       &h->tuple) &&
 449                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 450                         goto out;
 451
 452         add_timer(&ct->timeout);
 453         nf_conntrack_get(&ct->ct_general);
 454         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 455         NF_CT_STAT_INC(net, insert);
 456         spin_unlock_bh(&nf_conntrack_lock);
 457
 458         return 0;
 459
 460 out:
 461         NF_CT_STAT_INC(net, insert_failed);
 462         spin_unlock_bh(&nf_conntrack_lock);
 463         return -EEXIST;
 464 }
 465 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 466
 467 /* Confirm a connection given skb; places it in hash table */
 468 int
 469 __nf_conntrack_confirm(struct sk_buff *skb)
 470 {
 471         unsigned int hash, repl_hash;
 472         struct nf_conntrack_tuple_hash *h;
 473         struct nf_conn *ct;
 474         struct nf_conn_help *help;
 475         struct nf_conn_tstamp *tstamp;
 476         struct hlist_nulls_node *n;
 477         enum ip_conntrack_info ctinfo;
 478         struct net *net;
 479         u16 zone;
 480
 481         ct = nf_ct_get(skb, &ctinfo);
 482         net = nf_ct_net(ct);
 483
 484         /* ipt_REJECT uses nf_conntrack_attach to attach related
 485            ICMP/TCP RST packets in other direction.  Actual packet
 486            which created connection will be IP_CT_NEW or for an
 487            expected connection, IP_CT_RELATED. */
 488         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 489                 return NF_ACCEPT;
 490
 491         zone = nf_ct_zone(ct);
 492         /* reuse the hash saved before */
 493         hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 494         hash = hash_bucket(hash, net);
 495         repl_hash = hash_conntrack(net, zone,
 496                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 497
 498         /* We're not in hash table, and we refuse to set up related
 499            connections for unconfirmed conns.  But packet copies and
 500            REJECT will give spurious warnings here. */
 501         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 502
 503         /* No external references means no one else could have
 504            confirmed us. */
 505         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 506         pr_debug("Confirming conntrack %p\n", ct);
 507
 508         spin_lock_bh(&nf_conntrack_lock);
 509
 510         /* We have to check the DYING flag inside the lock to prevent
 511            a race against nf_ct_get_next_corpse() possibly called from
 512            user context, else we insert an already 'dead' hash, blocking
 513            further use of that particular connection -JM */
 514
 515         if (unlikely(nf_ct_is_dying(ct))) {
 516                 spin_unlock_bh(&nf_conntrack_lock);
 517                 return NF_ACCEPT;
 518         }
 519
 520         /* See if there's one in the list already, including reverse:
 521            NAT could have grabbed it without realizing, since we're
 522            not in the hash.  If there is, we lost race. */
 523         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 524                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 525                                       &h->tuple) &&
 526                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 527                         goto out;
 528         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 529                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 530                                       &h->tuple) &&
 531                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 532                         goto out;
 533
 534         /* Remove from unconfirmed list */
 535         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 536
 537         /* Timer relative to confirmation time, not original
 538            setting time, otherwise we'd get timer wrap in
 539            weird delay cases. */
 540         ct->timeout.expires += jiffies;
 541         add_timer(&ct->timeout);
 542         atomic_inc(&ct->ct_general.use);
 543         ct->status |= IPS_CONFIRMED;
 544
 545         /* set conntrack timestamp, if enabled. */
 546         tstamp = nf_conn_tstamp_find(ct);
 547         if (tstamp) {
 548                 if (skb->tstamp.tv64 == 0)
 549                         __net_timestamp(skb);
 550
 551                 tstamp->start = ktime_to_ns(skb->tstamp);
 552         }
 553         /* Since the lookup is lockless, hash insertion must be done after
 554          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 555          * guarantee that no other CPU can find the conntrack before the above
 556          * stores are visible.
 557          */
 558         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 559         NF_CT_STAT_INC(net, insert);
 560         spin_unlock_bh(&nf_conntrack_lock);
 561
 562         help = nfct_help(ct);
 563         if (help && help->helper)
 564                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 565
 566         nf_conntrack_event_cache(master_ct(ct) ?
 567                                  IPCT_RELATED : IPCT_NEW, ct);
 568         return NF_ACCEPT;
 569
 570 out:
 571         NF_CT_STAT_INC(net, insert_failed);
 572         spin_unlock_bh(&nf_conntrack_lock);
 573         return NF_DROP;
 574 }
 575 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 576
 577 /* Returns true if a connection correspondings to the tuple (required
 578    for NAT). */
 579 int
 580 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 581                          const struct nf_conn *ignored_conntrack)
 582 {
 583         struct net *net = nf_ct_net(ignored_conntrack);
 584         struct nf_conntrack_tuple_hash *h;
 585         struct hlist_nulls_node *n;
 586         struct nf_conn *ct;
 587         u16 zone = nf_ct_zone(ignored_conntrack);
 588         unsigned int hash = hash_conntrack(net, zone, tuple);
 589
 590         /* Disable BHs the entire time since we need to disable them at
 591          * least once for the stats anyway.
 592          */
 593         rcu_read_lock_bh();
 594         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 595                 ct = nf_ct_tuplehash_to_ctrack(h);
 596                 if (ct != ignored_conntrack &&
 597                     nf_ct_tuple_equal(tuple, &h->tuple) &&
 598                     nf_ct_zone(ct) == zone) {
 599                         NF_CT_STAT_INC(net, found);
 600                         rcu_read_unlock_bh();
 601                         return 1;
 602                 }
 603                 NF_CT_STAT_INC(net, searched);
 604         }
 605         rcu_read_unlock_bh();
 606
 607         return 0;
 608 }
 609 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 610
 611 #define NF_CT_EVICTION_RANGE    8
 612
 613 /* There's a small race here where we may free a just-assured
 614    connection.  Too bad: we're in trouble anyway. */
 615 static noinline int early_drop(struct net *net, unsigned int hash)
 616 {
 617         /* Use oldest entry, which is roughly LRU */
 618         struct nf_conntrack_tuple_hash *h;
 619         struct nf_conn *ct = NULL, *tmp;
 620         struct hlist_nulls_node *n;
 621         unsigned int i, cnt = 0;
 622         int dropped = 0;
 623
 624         rcu_read_lock();
 625         for (i = 0; i < net->ct.htable_size; i++) {
 626                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 627                                          hnnode) {
 628                         tmp = nf_ct_tuplehash_to_ctrack(h);
 629                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 630                                 ct = tmp;
 631                         cnt++;
 632                 }
 633
 634                 if (ct != NULL) {
 635                         if (likely(!nf_ct_is_dying(ct) &&
 636                                    atomic_inc_not_zero(&ct->ct_general.use)))
 637                                 break;
 638                         else
 639                                 ct = NULL;
 640                 }
 641
 642                 if (cnt >= NF_CT_EVICTION_RANGE)
 643                         break;
 644
 645                 hash = (hash + 1) % net->ct.htable_size;
 646         }
 647         rcu_read_unlock();
 648
 649         if (!ct)
 650                 return dropped;
 651
 652         if (del_timer(&ct->timeout)) {
 653                 if (nf_ct_delete(ct, 0, 0)) {
 654                         dropped = 1;
 655                         NF_CT_STAT_INC_ATOMIC(net, early_drop);
 656                 }
 657         }
 658         nf_ct_put(ct);
 659         return dropped;
 660 }
 661
 662 void init_nf_conntrack_hash_rnd(void)
 663 {
 664         unsigned int rand;
 665
 666         /*
 667          * Why not initialize nf_conntrack_rnd in a "init()" function ?
 668          * Because there isn't enough entropy when system initializing,
 669          * and we initialize it as late as possible.
 670          */
 671         do {
 672                 get_random_bytes(&rand, sizeof(rand));
 673         } while (!rand);
 674         cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
 675 }
 676
 677 static struct nf_conn *
 678 __nf_conntrack_alloc(struct net *net, u16 zone,
 679                      const struct nf_conntrack_tuple *orig,
 680                      const struct nf_conntrack_tuple *repl,
 681                      gfp_t gfp, u32 hash)
 682 {
 683         struct nf_conn *ct;
 684
 685         if (unlikely(!nf_conntrack_hash_rnd)) {
 686                 init_nf_conntrack_hash_rnd();
 687                 /* recompute the hash as nf_conntrack_hash_rnd is initialized */
 688                 hash = hash_conntrack_raw(orig, zone);
 689         }
 690
 691         /* We don't want any race condition at early drop stage */
 692         atomic_inc(&net->ct.count);
 693
 694         if (nf_conntrack_max &&
 695             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
 696                 if (!early_drop(net, hash_bucket(hash, net))) {
 697                         atomic_dec(&net->ct.count);
 698                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
 699                         return ERR_PTR(-ENOMEM);
 700                 }
 701         }
 702
 703         /*
 704          * Do not use kmem_cache_zalloc(), as this cache uses
 705          * SLAB_DESTROY_BY_RCU.
 706          */
 707         ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
 708         if (ct == NULL) {
 709                 atomic_dec(&net->ct.count);
 710                 return ERR_PTR(-ENOMEM);
 711         }
 712         /*
 713          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
 714          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
 715          */
 716         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
 717                offsetof(struct nf_conn, proto) -
 718                offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
 719         spin_lock_init(&ct->lock);
 720         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 721         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
 722         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 723         /* save hash for reusing when confirming */
 724         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
 725         /* Don't set timer yet: wait for confirmation */
 726         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 727         write_pnet(&ct->ct_net, net);
 728 #ifdef CONFIG_NF_CONNTRACK_ZONES
 729         if (zone) {
 730                 struct nf_conntrack_zone *nf_ct_zone;
 731
 732                 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC);
 733                 if (!nf_ct_zone)
 734                         goto out_free;
 735                 nf_ct_zone->id = zone;
 736         }
 737 #endif
 738         /*
 739          * changes to lookup keys must be done before setting refcnt to 1
 740          */
 741         smp_wmb();
 742         atomic_set(&ct->ct_general.use, 1);
 743         return ct;
 744
 745 #ifdef CONFIG_NF_CONNTRACK_ZONES
 746 out_free:
 747         atomic_dec(&net->ct.count);
 748         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 749         return ERR_PTR(-ENOMEM);
 750 #endif
 751 }
 752
 753 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
 754                                    const struct nf_conntrack_tuple *orig,
 755                                    const struct nf_conntrack_tuple *repl,
 756                                    gfp_t gfp)
 757 {
 758         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
 759 }
 760 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 761
 762 void nf_conntrack_free(struct nf_conn *ct)
 763 {
 764         struct net *net = nf_ct_net(ct);
 765
 766         nf_ct_ext_destroy(ct);
 767         nf_ct_ext_free(ct);
 768         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 769         smp_mb__before_atomic_dec();
 770         atomic_dec(&net->ct.count);
 771 }
 772 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 773
 774
 775 /* Allocate a new conntrack: we return -ENOMEM if classification
 776    failed due to stress.  Otherwise it really is unclassifiable. */
 777 static struct nf_conntrack_tuple_hash *
 778 init_conntrack(struct net *net, struct nf_conn *tmpl,
 779                const struct nf_conntrack_tuple *tuple,
 780                struct nf_conntrack_l3proto *l3proto,
 781                struct nf_conntrack_l4proto *l4proto,
 782                struct sk_buff *skb,
 783                unsigned int dataoff, u32 hash)
 784 {
 785         struct nf_conn *ct;
 786         struct nf_conn_help *help;
 787         struct nf_conntrack_tuple repl_tuple;
 788         struct nf_conntrack_ecache *ecache;
 789         struct nf_conntrack_expect *exp;
 790         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 791         struct nf_conn_timeout *timeout_ext;
 792         unsigned int *timeouts;
 793
 794         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 795                 pr_debug("Can't invert tuple.\n");
 796                 return NULL;
 797         }
 798
 799         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
 800                                   hash);
 801         if (IS_ERR(ct))
 802                 return (struct nf_conntrack_tuple_hash *)ct;
 803
 804         if (tmpl && nfct_synproxy(tmpl)) {
 805                 nfct_seqadj_ext_add(ct);
 806                 nfct_synproxy_ext_add(ct);
 807         }
 808
 809         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
 810         if (timeout_ext)
 811                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 812         else
 813                 timeouts = l4proto->get_timeouts(net);
 814
 815         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
 816                 nf_conntrack_free(ct);
 817                 pr_debug("init conntrack: can't track with proto module\n");
 818                 return NULL;
 819         }
 820
 821         if (timeout_ext)
 822                 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC);
 823
 824         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 825         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 826         nf_ct_labels_ext_add(ct);
 827
 828         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
 829         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
 830                                  ecache ? ecache->expmask : 0,
 831                              GFP_ATOMIC);
 832
 833         spin_lock_bh(&nf_conntrack_lock);
 834         exp = nf_ct_find_expectation(net, zone, tuple);
 835         if (exp) {
 836                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 837                          ct, exp);
 838                 /* Welcome, Mr. Bond.  We've been expecting you... */
 839                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
 840                 ct->master = exp->master;
 841                 if (exp->helper) {
 842                         help = nf_ct_helper_ext_add(ct, exp->helper,
 843                                                     GFP_ATOMIC);
 844                         if (help)
 845                                 rcu_assign_pointer(help->helper, exp->helper);
 846                 }
 847
 848 #ifdef CONFIG_NF_CONNTRACK_MARK
 849                 ct->mark = exp->master->mark;
 850 #endif
 851 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 852                 ct->secmark = exp->master->secmark;
 853 #endif
 854                 nf_conntrack_get(&ct->master->ct_general);
 855                 NF_CT_STAT_INC(net, expect_new);
 856         } else {
 857                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
 858                 NF_CT_STAT_INC(net, new);
 859         }
 860
 861         /* Overload tuple linked list to put us in unconfirmed list. */
 862         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 863                        &net->ct.unconfirmed);
 864
 865         spin_unlock_bh(&nf_conntrack_lock);
 866
 867         if (exp) {
 868                 if (exp->expectfn)
 869                         exp->expectfn(ct, exp);
 870                 nf_ct_expect_put(exp);
 871         }
 872
 873         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
 874 }
 875
 876 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 877 static inline struct nf_conn *
 878 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
 879                   struct sk_buff *skb,
 880                   unsigned int dataoff,
 881                   u_int16_t l3num,
 882                   u_int8_t protonum,
 883                   struct nf_conntrack_l3proto *l3proto,
 884                   struct nf_conntrack_l4proto *l4proto,
 885                   int *set_reply,
 886                   enum ip_conntrack_info *ctinfo)
 887 {
 888         struct nf_conntrack_tuple tuple;
 889         struct nf_conntrack_tuple_hash *h;
 890         struct nf_conn *ct;
 891         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 892         u32 hash;
 893
 894         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 895                              dataoff, l3num, protonum, &tuple, l3proto,
 896                              l4proto)) {
 897                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 898                 return NULL;
 899         }
 900
 901         /* look for tuple match */
 902         hash = hash_conntrack_raw(&tuple, zone);
 903         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
 904         if (!h) {
 905                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
 906                                    skb, dataoff, hash);
 907                 if (!h)
 908                         return NULL;
 909                 if (IS_ERR(h))
 910                         return (void *)h;
 911         }
 912         ct = nf_ct_tuplehash_to_ctrack(h);
 913
 914         /* It exists; we have (non-exclusive) reference. */
 915         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 916                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
 917                 /* Please set reply bit if this packet OK */
 918                 *set_reply = 1;
 919         } else {
 920                 /* Once we've had two way comms, always ESTABLISHED. */
 921                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 922                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 923                         *ctinfo = IP_CT_ESTABLISHED;
 924                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 925                         pr_debug("nf_conntrack_in: related packet for %p\n",
 926                                  ct);
 927                         *ctinfo = IP_CT_RELATED;
 928                 } else {
 929                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 930                         *ctinfo = IP_CT_NEW;
 931                 }
 932                 *set_reply = 0;
 933         }
 934         skb->nfct = &ct->ct_general;
 935         skb->nfctinfo = *ctinfo;
 936         return ct;
 937 }
 938
 939 unsigned int
 940 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 941                 struct sk_buff *skb)
 942 {
 943         struct nf_conn *ct, *tmpl = NULL;
 944         enum ip_conntrack_info ctinfo;
 945         struct nf_conntrack_l3proto *l3proto;
 946         struct nf_conntrack_l4proto *l4proto;
 947         unsigned int *timeouts;
 948         unsigned int dataoff;
 949         u_int8_t protonum;
 950         int set_reply = 0;
 951         int ret;
 952
 953         if (skb->nfct) {
 954                 /* Previously seen (loopback or untracked)?  Ignore. */
 955                 tmpl = (struct nf_conn *)skb->nfct;
 956                 if (!nf_ct_is_template(tmpl)) {
 957                         NF_CT_STAT_INC_ATOMIC(net, ignore);
 958                         return NF_ACCEPT;
 959                 }
 960                 skb->nfct = NULL;
 961         }
 962
 963         /* rcu_read_lock()ed by nf_hook_slow */
 964         l3proto = __nf_ct_l3proto_find(pf);
 965         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 966                                    &dataoff, &protonum);
 967         if (ret <= 0) {
 968                 pr_debug("not prepared to track yet or error occurred\n");
 969                 NF_CT_STAT_INC_ATOMIC(net, error);
 970                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 971                 ret = -ret;
 972                 goto out;
 973         }
 974
 975         l4proto = __nf_ct_l4proto_find(pf, protonum);
 976
 977         /* It may be an special packet, error, unclean...
 978          * inverse of the return code tells to the netfilter
 979          * core what to do with the packet. */
 980         if (l4proto->error != NULL) {
 981                 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
 982                                      pf, hooknum);
 983                 if (ret <= 0) {
 984                         NF_CT_STAT_INC_ATOMIC(net, error);
 985                         NF_CT_STAT_INC_ATOMIC(net, invalid);
 986                         ret = -ret;
 987                         goto out;
 988                 }
 989                 /* ICMP[v6] protocol trackers may assign one conntrack. */
 990                 if (skb->nfct)
 991                         goto out;
 992         }
 993
 994         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
 995                                l3proto, l4proto, &set_reply, &ctinfo);
 996         if (!ct) {
 997                 /* Not valid part of a connection */
 998                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 999                 ret = NF_ACCEPT;
1000                 goto out;
1001         }
1002
1003         if (IS_ERR(ct)) {
1004                 /* Too stressed to deal. */
1005                 NF_CT_STAT_INC_ATOMIC(net, drop);
1006                 ret = NF_DROP;
1007                 goto out;
1008         }
1009
1010         NF_CT_ASSERT(skb->nfct);
1011
1012         /* Decide what timeout policy we want to apply to this flow. */
1013         timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1014
1015         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1016         if (ret <= 0) {
1017                 /* Invalid: inverse of the return code tells
1018                  * the netfilter core what to do */
1019                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1020                 nf_conntrack_put(skb->nfct);
1021                 skb->nfct = NULL;
1022                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1023                 if (ret == -NF_DROP)
1024                         NF_CT_STAT_INC_ATOMIC(net, drop);
1025                 ret = -ret;
1026                 goto out;
1027         }
1028
1029         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1030                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1031 out:
1032         if (tmpl) {
1033                 /* Special case: we have to repeat this hook, assign the
1034                  * template again to this packet. We assume that this packet
1035                  * has no conntrack assigned. This is used by nf_ct_tcp. */
1036                 if (ret == NF_REPEAT)
1037                         skb->nfct = (struct nf_conntrack *)tmpl;
1038                 else
1039                         nf_ct_put(tmpl);
1040         }
1041
1042         return ret;
1043 }
1044 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1045
1046 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1047                           const struct nf_conntrack_tuple *orig)
1048 {
1049         bool ret;
1050
1051         rcu_read_lock();
1052         ret = nf_ct_invert_tuple(inverse, orig,
1053                                  __nf_ct_l3proto_find(orig->src.l3num),
1054                                  __nf_ct_l4proto_find(orig->src.l3num,
1055                                                       orig->dst.protonum));
1056         rcu_read_unlock();
1057         return ret;
1058 }
1059 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1060
1061 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1062    implicitly racy: see __nf_conntrack_confirm */
1063 void nf_conntrack_alter_reply(struct nf_conn *ct,
1064                               const struct nf_conntrack_tuple *newreply)
1065 {
1066         struct nf_conn_help *help = nfct_help(ct);
1067
1068         /* Should be unconfirmed, so not in hash table yet */
1069         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1070
1071         pr_debug("Altering reply tuple of %p to ", ct);
1072         nf_ct_dump_tuple(newreply);
1073
1074         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1075         if (ct->master || (help && !hlist_empty(&help->expectations)))
1076                 return;
1077
1078         rcu_read_lock();
1079         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1080         rcu_read_unlock();
1081 }
1082 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1083
1084 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1085 void __nf_ct_refresh_acct(struct nf_conn *ct,
1086                           enum ip_conntrack_info ctinfo,
1087                           const struct sk_buff *skb,
1088                           unsigned long extra_jiffies,
1089                           int do_acct)
1090 {
1091         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1092         NF_CT_ASSERT(skb);
1093
1094         /* Only update if this is not a fixed timeout */
1095         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1096                 goto acct;
1097
1098         /* If not in hash table, timer will not be active yet */
1099         if (!nf_ct_is_confirmed(ct)) {
1100                 ct->timeout.expires = extra_jiffies;
1101         } else {
1102                 unsigned long newtime = jiffies + extra_jiffies;
1103
1104                 /* Only update the timeout if the new timeout is at least
1105                    HZ jiffies from the old timeout. Need del_timer for race
1106                    avoidance (may already be dying). */
1107                 if (newtime - ct->timeout.expires >= HZ)
1108                         mod_timer_pending(&ct->timeout, newtime);
1109         }
1110
1111 acct:
1112         if (do_acct) {
1113                 struct nf_conn_acct *acct;
1114
1115                 acct = nf_conn_acct_find(ct);
1116                 if (acct) {
1117                         struct nf_conn_counter *counter = acct->counter;
1118
1119                         atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
1120                         atomic64_add(skb->len, &counter[CTINFO2DIR(ctinfo)].bytes);
1121                 }
1122         }
1123 }
1124 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1125
1126 bool __nf_ct_kill_acct(struct nf_conn *ct,
1127                        enum ip_conntrack_info ctinfo,
1128                        const struct sk_buff *skb,
1129                        int do_acct)
1130 {
1131         if (do_acct) {
1132                 struct nf_conn_acct *acct;
1133
1134                 acct = nf_conn_acct_find(ct);
1135                 if (acct) {
1136                         struct nf_conn_counter *counter = acct->counter;
1137
1138                         atomic64_inc(&counter[CTINFO2DIR(ctinfo)].packets);
1139                         atomic64_add(skb->len - skb_network_offset(skb),
1140                                      &counter[CTINFO2DIR(ctinfo)].bytes);
1141                 }
1142         }
1143
1144         if (del_timer(&ct->timeout)) {
1145                 ct->timeout.function((unsigned long)ct);
1146                 return true;
1147         }
1148         return false;
1149 }
1150 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1151
1152 #ifdef CONFIG_NF_CONNTRACK_ZONES
1153 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1154         .len    = sizeof(struct nf_conntrack_zone),
1155         .align  = __alignof__(struct nf_conntrack_zone),
1156         .id     = NF_CT_EXT_ZONE,
1157 };
1158 #endif
1159
1160 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1161
1162 #include <linux/netfilter/nfnetlink.h>
1163 #include <linux/netfilter/nfnetlink_conntrack.h>
1164 #include <linux/mutex.h>
1165
1166 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1167  * in ip_conntrack_core, since we don't want the protocols to autoload
1168  * or depend on ctnetlink */
1169 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1170                                const struct nf_conntrack_tuple *tuple)
1171 {
1172         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1173             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1174                 goto nla_put_failure;
1175         return 0;
1176
1177 nla_put_failure:
1178         return -1;
1179 }
1180 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1181
1182 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1183         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1184         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1185 };
1186 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1187
1188 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1189                                struct nf_conntrack_tuple *t)
1190 {
1191         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1192                 return -EINVAL;
1193
1194         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1195         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1196
1197         return 0;
1198 }
1199 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1200
1201 int nf_ct_port_nlattr_tuple_size(void)
1202 {
1203         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1204 }
1205 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1206 #endif
1207
1208 /* Used by ipt_REJECT and ip6t_REJECT. */
1209 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1210 {
1211         struct nf_conn *ct;
1212         enum ip_conntrack_info ctinfo;
1213
1214         /* This ICMP is in reverse direction to the packet which caused it */
1215         ct = nf_ct_get(skb, &ctinfo);
1216         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1217                 ctinfo = IP_CT_RELATED_REPLY;
1218         else
1219                 ctinfo = IP_CT_RELATED;
1220
1221         /* Attach to new skbuff, and increment count */
1222         nskb->nfct = &ct->ct_general;
1223         nskb->nfctinfo = ctinfo;
1224         nf_conntrack_get(nskb->nfct);
1225 }
1226
1227 /* Bring out ya dead! */
1228 static struct nf_conn *
1229 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1230                 void *data, unsigned int *bucket)
1231 {
1232         struct nf_conntrack_tuple_hash *h;
1233         struct nf_conn *ct;
1234         struct hlist_nulls_node *n;
1235
1236         spin_lock_bh(&nf_conntrack_lock);
1237         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1238                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1239                         if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
1240                                 continue;
1241                         ct = nf_ct_tuplehash_to_ctrack(h);
1242                         if (iter(ct, data))
1243                                 goto found;
1244                 }
1245         }
1246         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1247                 ct = nf_ct_tuplehash_to_ctrack(h);
1248                 if (iter(ct, data))
1249                         set_bit(IPS_DYING_BIT, &ct->status);
1250         }
1251         spin_unlock_bh(&nf_conntrack_lock);
1252         return NULL;
1253 found:
1254         atomic_inc(&ct->ct_general.use);
1255         spin_unlock_bh(&nf_conntrack_lock);
1256         return ct;
1257 }
1258
1259 void nf_ct_iterate_cleanup(struct net *net,
1260                            int (*iter)(struct nf_conn *i, void *data),
1261                            void *data, u32 portid, int report)
1262 {
1263         struct nf_conn *ct;
1264         unsigned int bucket = 0;
1265
1266         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1267                 /* Time to push up daises... */
1268                 if (del_timer(&ct->timeout))
1269                         nf_ct_delete(ct, portid, report);
1270
1271                 /* ... else the timer will get him soon. */
1272
1273                 nf_ct_put(ct);
1274         }
1275 }
1276 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1277
1278 static int kill_all(struct nf_conn *i, void *data)
1279 {
1280         return 1;
1281 }
1282
1283 void nf_ct_free_hashtable(void *hash, unsigned int size)
1284 {
1285         if (is_vmalloc_addr(hash))
1286                 vfree(hash);
1287         else
1288                 free_pages((unsigned long)hash,
1289                            get_order(sizeof(struct hlist_head) * size));
1290 }
1291 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1292
1293 void nf_conntrack_flush_report(struct net *net, u32 portid, int report)
1294 {
1295         nf_ct_iterate_cleanup(net, kill_all, NULL, portid, report);
1296 }
1297 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1298
1299 static void nf_ct_release_dying_list(struct net *net)
1300 {
1301         struct nf_conntrack_tuple_hash *h;
1302         struct nf_conn *ct;
1303         struct hlist_nulls_node *n;
1304
1305         spin_lock_bh(&nf_conntrack_lock);
1306         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1307                 ct = nf_ct_tuplehash_to_ctrack(h);
1308                 /* never fails to remove them, no listeners at this point */
1309                 nf_ct_kill(ct);
1310         }
1311         spin_unlock_bh(&nf_conntrack_lock);
1312 }
1313
1314 static int untrack_refs(void)
1315 {
1316         int cnt = 0, cpu;
1317
1318         for_each_possible_cpu(cpu) {
1319                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1320
1321                 cnt += atomic_read(&ct->ct_general.use) - 1;
1322         }
1323         return cnt;
1324 }
1325
1326 void nf_conntrack_cleanup_start(void)
1327 {
1328         RCU_INIT_POINTER(ip_ct_attach, NULL);
1329 }
1330
1331 void nf_conntrack_cleanup_end(void)
1332 {
1333         RCU_INIT_POINTER(nf_ct_destroy, NULL);
1334         while (untrack_refs() > 0)
1335                 schedule();
1336
1337 #ifdef CONFIG_NF_CONNTRACK_ZONES
1338         nf_ct_extend_unregister(&nf_ct_zone_extend);
1339 #endif
1340         nf_conntrack_proto_fini();
1341         nf_conntrack_seqadj_fini();
1342         nf_conntrack_labels_fini();
1343         nf_conntrack_helper_fini();
1344         nf_conntrack_timeout_fini();
1345         nf_conntrack_ecache_fini();
1346         nf_conntrack_tstamp_fini();
1347         nf_conntrack_acct_fini();
1348         nf_conntrack_expect_fini();
1349 }
1350
1351 /*
1352  * Mishearing the voices in his head, our hero wonders how he's
1353  * supposed to kill the mall.
1354  */
1355 void nf_conntrack_cleanup_net(struct net *net)
1356 {
1357         LIST_HEAD(single);
1358
1359         list_add(&net->exit_list, &single);
1360         nf_conntrack_cleanup_net_list(&single);
1361 }
1362
1363 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
1364 {
1365         int busy;
1366         struct net *net;
1367
1368         /*
1369          * This makes sure all current packets have passed through
1370          *  netfilter framework.  Roll on, two-stage module
1371          *  delete...
1372          */
1373         synchronize_net();
1374 i_see_dead_people:
1375         busy = 0;
1376         list_for_each_entry(net, net_exit_list, exit_list) {
1377                 nf_ct_iterate_cleanup(net, kill_all, NULL, 0, 0);
1378                 nf_ct_release_dying_list(net);
1379                 if (atomic_read(&net->ct.count) != 0)
1380                         busy = 1;
1381         }
1382         if (busy) {
1383                 schedule();
1384                 goto i_see_dead_people;
1385         }
1386
1387         list_for_each_entry(net, net_exit_list, exit_list) {
1388                 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1389                 nf_conntrack_proto_pernet_fini(net);
1390                 nf_conntrack_helper_pernet_fini(net);
1391                 nf_conntrack_ecache_pernet_fini(net);
1392                 nf_conntrack_tstamp_pernet_fini(net);
1393                 nf_conntrack_acct_pernet_fini(net);
1394                 nf_conntrack_expect_pernet_fini(net);
1395                 kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1396                 kfree(net->ct.slabname);
1397                 free_percpu(net->ct.stat);
1398         }
1399 }
1400
1401 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1402 {
1403         struct hlist_nulls_head *hash;
1404         unsigned int nr_slots, i;
1405         size_t sz;
1406
1407         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1408         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1409         sz = nr_slots * sizeof(struct hlist_nulls_head);
1410         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1411                                         get_order(sz));
1412         if (!hash) {
1413                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1414                 hash = vzalloc(sz);
1415         }
1416
1417         if (hash && nulls)
1418                 for (i = 0; i < nr_slots; i++)
1419                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1420
1421         return hash;
1422 }
1423 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1424
1425 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1426 {
1427         int i, bucket, rc;
1428         unsigned int hashsize, old_size;
1429         struct hlist_nulls_head *hash, *old_hash;
1430         struct nf_conntrack_tuple_hash *h;
1431         struct nf_conn *ct;
1432
1433         if (current->nsproxy->net_ns != &init_net)
1434                 return -EOPNOTSUPP;
1435
1436         /* On boot, we can set this without any fancy locking. */
1437         if (!nf_conntrack_htable_size)
1438                 return param_set_uint(val, kp);
1439
1440         rc = kstrtouint(val, 0, &hashsize);
1441         if (rc)
1442                 return rc;
1443         if (!hashsize)
1444                 return -EINVAL;
1445
1446         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1447         if (!hash)
1448                 return -ENOMEM;
1449
1450         /* Lookups in the old hash might happen in parallel, which means we
1451          * might get false negatives during connection lookup. New connections
1452          * created because of a false negative won't make it into the hash
1453          * though since that required taking the lock.
1454          */
1455         spin_lock_bh(&nf_conntrack_lock);
1456         for (i = 0; i < init_net.ct.htable_size; i++) {
1457                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1458                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1459                                         struct nf_conntrack_tuple_hash, hnnode);
1460                         ct = nf_ct_tuplehash_to_ctrack(h);
1461                         hlist_nulls_del_rcu(&h->hnnode);
1462                         bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct),
1463                                                   hashsize);
1464                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1465                 }
1466         }
1467         old_size = init_net.ct.htable_size;
1468         old_hash = init_net.ct.hash;
1469
1470         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1471         init_net.ct.hash = hash;
1472         spin_unlock_bh(&nf_conntrack_lock);
1473
1474         nf_ct_free_hashtable(old_hash, old_size);
1475         return 0;
1476 }
1477 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1478
1479 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1480                   &nf_conntrack_htable_size, 0600);
1481
1482 void nf_ct_untracked_status_or(unsigned long bits)
1483 {
1484         int cpu;
1485
1486         for_each_possible_cpu(cpu)
1487                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1488 }
1489 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1490
1491 int nf_conntrack_init_start(void)
1492 {
1493         int max_factor = 8;
1494         int ret, cpu;
1495
1496         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1497          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1498         if (!nf_conntrack_htable_size) {
1499                 nf_conntrack_htable_size
1500                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1501                            / sizeof(struct hlist_head));
1502                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1503                         nf_conntrack_htable_size = 16384;
1504                 if (nf_conntrack_htable_size < 32)
1505                         nf_conntrack_htable_size = 32;
1506
1507                 /* Use a max. factor of four by default to get the same max as
1508                  * with the old struct list_heads. When a table size is given
1509                  * we use the old value of 8 to avoid reducing the max.
1510                  * entries. */
1511                 max_factor = 4;
1512         }
1513         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1514
1515         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1516                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1517                nf_conntrack_max);
1518
1519         ret = nf_conntrack_expect_init();
1520         if (ret < 0)
1521                 goto err_expect;
1522
1523         ret = nf_conntrack_acct_init();
1524         if (ret < 0)
1525                 goto err_acct;
1526
1527         ret = nf_conntrack_tstamp_init();
1528         if (ret < 0)
1529                 goto err_tstamp;
1530
1531         ret = nf_conntrack_ecache_init();
1532         if (ret < 0)
1533                 goto err_ecache;
1534
1535         ret = nf_conntrack_timeout_init();
1536         if (ret < 0)
1537                 goto err_timeout;
1538
1539         ret = nf_conntrack_helper_init();
1540         if (ret < 0)
1541                 goto err_helper;
1542
1543         ret = nf_conntrack_labels_init();
1544         if (ret < 0)
1545                 goto err_labels;
1546
1547         ret = nf_conntrack_seqadj_init();
1548         if (ret < 0)
1549                 goto err_seqadj;
1550
1551 #ifdef CONFIG_NF_CONNTRACK_ZONES
1552         ret = nf_ct_extend_register(&nf_ct_zone_extend);
1553         if (ret < 0)
1554                 goto err_extend;
1555 #endif
1556         ret = nf_conntrack_proto_init();
1557         if (ret < 0)
1558                 goto err_proto;
1559
1560         /* Set up fake conntrack: to never be deleted, not in any hashes */
1561         for_each_possible_cpu(cpu) {
1562                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1563                 write_pnet(&ct->ct_net, &init_net);
1564                 atomic_set(&ct->ct_general.use, 1);
1565         }
1566         /*  - and look it like as a confirmed connection */
1567         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1568         return 0;
1569
1570 err_proto:
1571 #ifdef CONFIG_NF_CONNTRACK_ZONES
1572         nf_ct_extend_unregister(&nf_ct_zone_extend);
1573 err_extend:
1574 #endif
1575         nf_conntrack_seqadj_fini();
1576 err_seqadj:
1577         nf_conntrack_labels_fini();
1578 err_labels:
1579         nf_conntrack_helper_fini();
1580 err_helper:
1581         nf_conntrack_timeout_fini();
1582 err_timeout:
1583         nf_conntrack_ecache_fini();
1584 err_ecache:
1585         nf_conntrack_tstamp_fini();
1586 err_tstamp:
1587         nf_conntrack_acct_fini();
1588 err_acct:
1589         nf_conntrack_expect_fini();
1590 err_expect:
1591         return ret;
1592 }
1593
1594 void nf_conntrack_init_end(void)
1595 {
1596         /* For use by REJECT target */
1597         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1598         RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1599 }
1600
1601 /*
1602  * We need to use special "null" values, not used in hash table
1603  */
1604 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1605 #define DYING_NULLS_VAL         ((1<<30)+1)
1606 #define TEMPLATE_NULLS_VAL      ((1<<30)+2)
1607
1608 int nf_conntrack_init_net(struct net *net)
1609 {
1610         int ret;
1611
1612         atomic_set(&net->ct.count, 0);
1613         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1614         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1615         INIT_HLIST_NULLS_HEAD(&net->ct.tmpl, TEMPLATE_NULLS_VAL);
1616         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1617         if (!net->ct.stat) {
1618                 ret = -ENOMEM;
1619                 goto err_stat;
1620         }
1621
1622         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1623         if (!net->ct.slabname) {
1624                 ret = -ENOMEM;
1625                 goto err_slabname;
1626         }
1627
1628         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1629                                                         sizeof(struct nf_conn), 0,
1630                                                         SLAB_DESTROY_BY_RCU, NULL);
1631         if (!net->ct.nf_conntrack_cachep) {
1632                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1633                 ret = -ENOMEM;
1634                 goto err_cache;
1635         }
1636
1637         net->ct.htable_size = nf_conntrack_htable_size;
1638         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1639         if (!net->ct.hash) {
1640                 ret = -ENOMEM;
1641                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1642                 goto err_hash;
1643         }
1644         ret = nf_conntrack_expect_pernet_init(net);
1645         if (ret < 0)
1646                 goto err_expect;
1647         ret = nf_conntrack_acct_pernet_init(net);
1648         if (ret < 0)
1649                 goto err_acct;
1650         ret = nf_conntrack_tstamp_pernet_init(net);
1651         if (ret < 0)
1652                 goto err_tstamp;
1653         ret = nf_conntrack_ecache_pernet_init(net);
1654         if (ret < 0)
1655                 goto err_ecache;
1656         ret = nf_conntrack_helper_pernet_init(net);
1657         if (ret < 0)
1658                 goto err_helper;
1659         ret = nf_conntrack_proto_pernet_init(net);
1660         if (ret < 0)
1661                 goto err_proto;
1662         return 0;
1663
1664 err_proto:
1665         nf_conntrack_helper_pernet_fini(net);
1666 err_helper:
1667         nf_conntrack_ecache_pernet_fini(net);
1668 err_ecache:
1669         nf_conntrack_tstamp_pernet_fini(net);
1670 err_tstamp:
1671         nf_conntrack_acct_pernet_fini(net);
1672 err_acct:
1673         nf_conntrack_expect_pernet_fini(net);
1674 err_expect:
1675         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1676 err_hash:
1677         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1678 err_cache:
1679         kfree(net->ct.slabname);
1680 err_slabname:
1681         free_percpu(net->ct.stat);
1682 err_stat:
1683         return ret;
1684 }