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  *
   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         struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct);
 259
 260         BUG_ON(ecache == NULL);
 261
 262         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
 263                 /* bad luck, let's retry again */
 264                 ecache->timeout.expires = jiffies +
 265                         (random32() % net->ct.sysctl_events_retry_timeout);
 266                 add_timer(&ecache->timeout);
 267                 return;
 268         }
 269         /* we've got the event delivered, now it's dying */
 270         set_bit(IPS_DYING_BIT, &ct->status);
 271         spin_lock(&nf_conntrack_lock);
 272         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 273         spin_unlock(&nf_conntrack_lock);
 274         nf_ct_put(ct);
 275 }
 276
 277 void nf_ct_insert_dying_list(struct nf_conn *ct)
 278 {
 279         struct net *net = nf_ct_net(ct);
 280         struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct);
 281
 282         BUG_ON(ecache == NULL);
 283
 284         /* add this conntrack to the dying list */
 285         spin_lock_bh(&nf_conntrack_lock);
 286         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 287                              &net->ct.dying);
 288         spin_unlock_bh(&nf_conntrack_lock);
 289         /* set a new timer to retry event delivery */
 290         setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct);
 291         ecache->timeout.expires = jiffies +
 292                 (random32() % net->ct.sysctl_events_retry_timeout);
 293         add_timer(&ecache->timeout);
 294 }
 295 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
 296
 297 static void death_by_timeout(unsigned long ul_conntrack)
 298 {
 299         struct nf_conn *ct = (void *)ul_conntrack;
 300         struct nf_conn_tstamp *tstamp;
 301
 302         tstamp = nf_conn_tstamp_find(ct);
 303         if (tstamp && tstamp->stop == 0)
 304                 tstamp->stop = ktime_to_ns(ktime_get_real());
 305
 306         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
 307             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
 308                 /* destroy event was not delivered */
 309                 nf_ct_delete_from_lists(ct);
 310                 nf_ct_insert_dying_list(ct);
 311                 return;
 312         }
 313         set_bit(IPS_DYING_BIT, &ct->status);
 314         nf_ct_delete_from_lists(ct);
 315         nf_ct_put(ct);
 316 }
 317
 318 /*
 319  * Warning :
 320  * - Caller must take a reference on returned object
 321  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 322  * OR
 323  * - Caller must lock nf_conntrack_lock before calling this function
 324  */
 325 static struct nf_conntrack_tuple_hash *
 326 ____nf_conntrack_find(struct net *net, u16 zone,
 327                       const struct nf_conntrack_tuple *tuple, u32 hash)
 328 {
 329         struct nf_conntrack_tuple_hash *h;
 330         struct hlist_nulls_node *n;
 331         unsigned int bucket = hash_bucket(hash, net);
 332
 333         /* Disable BHs the entire time since we normally need to disable them
 334          * at least once for the stats anyway.
 335          */
 336         local_bh_disable();
 337 begin:
 338         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) {
 339                 if (nf_ct_tuple_equal(tuple, &h->tuple) &&
 340                     nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) {
 341                         NF_CT_STAT_INC(net, found);
 342                         local_bh_enable();
 343                         return h;
 344                 }
 345                 NF_CT_STAT_INC(net, searched);
 346         }
 347         /*
 348          * if the nulls value we got at the end of this lookup is
 349          * not the expected one, we must restart lookup.
 350          * We probably met an item that was moved to another chain.
 351          */
 352         if (get_nulls_value(n) != bucket) {
 353                 NF_CT_STAT_INC(net, search_restart);
 354                 goto begin;
 355         }
 356         local_bh_enable();
 357
 358         return NULL;
 359 }
 360
 361 struct nf_conntrack_tuple_hash *
 362 __nf_conntrack_find(struct net *net, u16 zone,
 363                     const struct nf_conntrack_tuple *tuple)
 364 {
 365         return ____nf_conntrack_find(net, zone, tuple,
 366                                      hash_conntrack_raw(tuple, zone));
 367 }
 368 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 369
 370 /* Find a connection corresponding to a tuple. */
 371 static struct nf_conntrack_tuple_hash *
 372 __nf_conntrack_find_get(struct net *net, u16 zone,
 373                         const struct nf_conntrack_tuple *tuple, u32 hash)
 374 {
 375         struct nf_conntrack_tuple_hash *h;
 376         struct nf_conn *ct;
 377
 378         rcu_read_lock();
 379 begin:
 380         h = ____nf_conntrack_find(net, zone, tuple, hash);
 381         if (h) {
 382                 ct = nf_ct_tuplehash_to_ctrack(h);
 383                 if (unlikely(nf_ct_is_dying(ct) ||
 384                              !atomic_inc_not_zero(&ct->ct_general.use)))
 385                         h = NULL;
 386                 else {
 387                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) ||
 388                                      nf_ct_zone(ct) != zone)) {
 389                                 nf_ct_put(ct);
 390                                 goto begin;
 391                         }
 392                 }
 393         }
 394         rcu_read_unlock();
 395
 396         return h;
 397 }
 398
 399 struct nf_conntrack_tuple_hash *
 400 nf_conntrack_find_get(struct net *net, u16 zone,
 401                       const struct nf_conntrack_tuple *tuple)
 402 {
 403         return __nf_conntrack_find_get(net, zone, tuple,
 404                                        hash_conntrack_raw(tuple, zone));
 405 }
 406 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 407
 408 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 409                                        unsigned int hash,
 410                                        unsigned int repl_hash)
 411 {
 412         struct net *net = nf_ct_net(ct);
 413
 414         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 415                            &net->ct.hash[hash]);
 416         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 417                            &net->ct.hash[repl_hash]);
 418 }
 419
 420 int
 421 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 422 {
 423         struct net *net = nf_ct_net(ct);
 424         unsigned int hash, repl_hash;
 425         struct nf_conntrack_tuple_hash *h;
 426         struct hlist_nulls_node *n;
 427         u16 zone;
 428
 429         zone = nf_ct_zone(ct);
 430         hash = hash_conntrack(net, zone,
 431                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 432         repl_hash = hash_conntrack(net, zone,
 433                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 434
 435         spin_lock_bh(&nf_conntrack_lock);
 436
 437         /* See if there's one in the list already, including reverse */
 438         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 439                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 440                                       &h->tuple) &&
 441                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 442                         goto out;
 443         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 444                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 445                                       &h->tuple) &&
 446                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 447                         goto out;
 448
 449         add_timer(&ct->timeout);
 450         nf_conntrack_get(&ct->ct_general);
 451         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 452         NF_CT_STAT_INC(net, insert);
 453         spin_unlock_bh(&nf_conntrack_lock);
 454
 455         return 0;
 456
 457 out:
 458         NF_CT_STAT_INC(net, insert_failed);
 459         spin_unlock_bh(&nf_conntrack_lock);
 460         return -EEXIST;
 461 }
 462 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 463
 464 /* Confirm a connection given skb; places it in hash table */
 465 int
 466 __nf_conntrack_confirm(struct sk_buff *skb)
 467 {
 468         unsigned int hash, repl_hash;
 469         struct nf_conntrack_tuple_hash *h;
 470         struct nf_conn *ct;
 471         struct nf_conn_help *help;
 472         struct nf_conn_tstamp *tstamp;
 473         struct hlist_nulls_node *n;
 474         enum ip_conntrack_info ctinfo;
 475         struct net *net;
 476         u16 zone;
 477
 478         ct = nf_ct_get(skb, &ctinfo);
 479         net = nf_ct_net(ct);
 480
 481         /* ipt_REJECT uses nf_conntrack_attach to attach related
 482            ICMP/TCP RST packets in other direction.  Actual packet
 483            which created connection will be IP_CT_NEW or for an
 484            expected connection, IP_CT_RELATED. */
 485         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 486                 return NF_ACCEPT;
 487
 488         zone = nf_ct_zone(ct);
 489         /* reuse the hash saved before */
 490         hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 491         hash = hash_bucket(hash, net);
 492         repl_hash = hash_conntrack(net, zone,
 493                                    &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 494
 495         /* We're not in hash table, and we refuse to set up related
 496            connections for unconfirmed conns.  But packet copies and
 497            REJECT will give spurious warnings here. */
 498         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 499
 500         /* No external references means no one else could have
 501            confirmed us. */
 502         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 503         pr_debug("Confirming conntrack %p\n", ct);
 504
 505         spin_lock_bh(&nf_conntrack_lock);
 506
 507         /* We have to check the DYING flag inside the lock to prevent
 508            a race against nf_ct_get_next_corpse() possibly called from
 509            user context, else we insert an already 'dead' hash, blocking
 510            further use of that particular connection -JM */
 511
 512         if (unlikely(nf_ct_is_dying(ct))) {
 513                 spin_unlock_bh(&nf_conntrack_lock);
 514                 return NF_ACCEPT;
 515         }
 516
 517         /* See if there's one in the list already, including reverse:
 518            NAT could have grabbed it without realizing, since we're
 519            not in the hash.  If there is, we lost race. */
 520         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 521                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 522                                       &h->tuple) &&
 523                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 524                         goto out;
 525         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 526                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 527                                       &h->tuple) &&
 528                     zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
 529                         goto out;
 530
 531         /* Remove from unconfirmed list */
 532         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 533
 534         /* Timer relative to confirmation time, not original
 535            setting time, otherwise we'd get timer wrap in
 536            weird delay cases. */
 537         ct->timeout.expires += jiffies;
 538         add_timer(&ct->timeout);
 539         atomic_inc(&ct->ct_general.use);
 540         ct->status |= IPS_CONFIRMED;
 541
 542         /* set conntrack timestamp, if enabled. */
 543         tstamp = nf_conn_tstamp_find(ct);
 544         if (tstamp) {
 545                 if (skb->tstamp.tv64 == 0)
 546                         __net_timestamp(skb);
 547
 548                 tstamp->start = ktime_to_ns(skb->tstamp);
 549         }
 550         /* Since the lookup is lockless, hash insertion must be done after
 551          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 552          * guarantee that no other CPU can find the conntrack before the above
 553          * stores are visible.
 554          */
 555         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 556         NF_CT_STAT_INC(net, insert);
 557         spin_unlock_bh(&nf_conntrack_lock);
 558
 559         help = nfct_help(ct);
 560         if (help && help->helper)
 561                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 562
 563         nf_conntrack_event_cache(master_ct(ct) ?
 564                                  IPCT_RELATED : IPCT_NEW, ct);
 565         return NF_ACCEPT;
 566
 567 out:
 568         NF_CT_STAT_INC(net, insert_failed);
 569         spin_unlock_bh(&nf_conntrack_lock);
 570         return NF_DROP;
 571 }
 572 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 573
 574 /* Returns true if a connection correspondings to the tuple (required
 575    for NAT). */
 576 int
 577 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 578                          const struct nf_conn *ignored_conntrack)
 579 {
 580         struct net *net = nf_ct_net(ignored_conntrack);
 581         struct nf_conntrack_tuple_hash *h;
 582         struct hlist_nulls_node *n;
 583         struct nf_conn *ct;
 584         u16 zone = nf_ct_zone(ignored_conntrack);
 585         unsigned int hash = hash_conntrack(net, zone, tuple);
 586
 587         /* Disable BHs the entire time since we need to disable them at
 588          * least once for the stats anyway.
 589          */
 590         rcu_read_lock_bh();
 591         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 592                 ct = nf_ct_tuplehash_to_ctrack(h);
 593                 if (ct != ignored_conntrack &&
 594                     nf_ct_tuple_equal(tuple, &h->tuple) &&
 595                     nf_ct_zone(ct) == zone) {
 596                         NF_CT_STAT_INC(net, found);
 597                         rcu_read_unlock_bh();
 598                         return 1;
 599                 }
 600                 NF_CT_STAT_INC(net, searched);
 601         }
 602         rcu_read_unlock_bh();
 603
 604         return 0;
 605 }
 606 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 607
 608 #define NF_CT_EVICTION_RANGE    8
 609
 610 /* There's a small race here where we may free a just-assured
 611    connection.  Too bad: we're in trouble anyway. */
 612 static noinline int early_drop(struct net *net, unsigned int hash)
 613 {
 614         /* Use oldest entry, which is roughly LRU */
 615         struct nf_conntrack_tuple_hash *h;
 616         struct nf_conn *ct = NULL, *tmp;
 617         struct hlist_nulls_node *n;
 618         unsigned int i, cnt = 0;
 619         int dropped = 0;
 620
 621         rcu_read_lock();
 622         for (i = 0; i < net->ct.htable_size; i++) {
 623                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 624                                          hnnode) {
 625                         tmp = nf_ct_tuplehash_to_ctrack(h);
 626                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 627                                 ct = tmp;
 628                         cnt++;
 629                 }
 630
 631                 if (ct != NULL) {
 632                         if (likely(!nf_ct_is_dying(ct) &&
 633                                    atomic_inc_not_zero(&ct->ct_general.use)))
 634                                 break;
 635                         else
 636                                 ct = NULL;
 637                 }
 638
 639                 if (cnt >= NF_CT_EVICTION_RANGE)
 640                         break;
 641
 642                 hash = (hash + 1) % net->ct.htable_size;
 643         }
 644         rcu_read_unlock();
 645
 646         if (!ct)
 647                 return dropped;
 648
 649         if (del_timer(&ct->timeout)) {
 650                 death_by_timeout((unsigned long)ct);
 651                 /* Check if we indeed killed this entry. Reliable event
 652                    delivery may have inserted it into the dying list. */
 653                 if (test_bit(IPS_DYING_BIT, &ct->status)) {
 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         atomic_dec(&net->ct.count);
 768         nf_ct_ext_free(ct);
 769         kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
 770 }
 771 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 772
 773 /* Allocate a new conntrack: we return -ENOMEM if classification
 774    failed due to stress.  Otherwise it really is unclassifiable. */
 775 static struct nf_conntrack_tuple_hash *
 776 init_conntrack(struct net *net, struct nf_conn *tmpl,
 777                const struct nf_conntrack_tuple *tuple,
 778                struct nf_conntrack_l3proto *l3proto,
 779                struct nf_conntrack_l4proto *l4proto,
 780                struct sk_buff *skb,
 781                unsigned int dataoff, u32 hash)
 782 {
 783         struct nf_conn *ct;
 784         struct nf_conn_help *help;
 785         struct nf_conntrack_tuple repl_tuple;
 786         struct nf_conntrack_ecache *ecache;
 787         struct nf_conntrack_expect *exp;
 788         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 789         struct nf_conn_timeout *timeout_ext;
 790         unsigned int *timeouts;
 791
 792         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 793                 pr_debug("Can't invert tuple.\n");
 794                 return NULL;
 795         }
 796
 797         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
 798                                   hash);
 799         if (IS_ERR(ct))
 800                 return (struct nf_conntrack_tuple_hash *)ct;
 801
 802         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
 803         if (timeout_ext)
 804                 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext);
 805         else
 806                 timeouts = l4proto->get_timeouts(net);
 807
 808         if (!l4proto->new(ct, skb, dataoff, timeouts)) {
 809                 nf_conntrack_free(ct);
 810                 pr_debug("init conntrack: can't track with proto module\n");
 811                 return NULL;
 812         }
 813
 814         if (timeout_ext)
 815                 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC);
 816
 817         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 818         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
 819
 820         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
 821         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
 822                                  ecache ? ecache->expmask : 0,
 823                              GFP_ATOMIC);
 824
 825         spin_lock_bh(&nf_conntrack_lock);
 826         exp = nf_ct_find_expectation(net, zone, tuple);
 827         if (exp) {
 828                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 829                          ct, exp);
 830                 /* Welcome, Mr. Bond.  We've been expecting you... */
 831                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
 832                 ct->master = exp->master;
 833                 if (exp->helper) {
 834                         help = nf_ct_helper_ext_add(ct, exp->helper,
 835                                                     GFP_ATOMIC);
 836                         if (help)
 837                                 rcu_assign_pointer(help->helper, exp->helper);
 838                 }
 839
 840 #ifdef CONFIG_NF_CONNTRACK_MARK
 841                 ct->mark = exp->master->mark;
 842 #endif
 843 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 844                 ct->secmark = exp->master->secmark;
 845 #endif
 846                 nf_conntrack_get(&ct->master->ct_general);
 847                 NF_CT_STAT_INC(net, expect_new);
 848         } else {
 849                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
 850                 NF_CT_STAT_INC(net, new);
 851         }
 852
 853         /* Overload tuple linked list to put us in unconfirmed list. */
 854         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 855                        &net->ct.unconfirmed);
 856
 857         spin_unlock_bh(&nf_conntrack_lock);
 858
 859         if (exp) {
 860                 if (exp->expectfn)
 861                         exp->expectfn(ct, exp);
 862                 nf_ct_expect_put(exp);
 863         }
 864
 865         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
 866 }
 867
 868 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 869 static inline struct nf_conn *
 870 resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
 871                   struct sk_buff *skb,
 872                   unsigned int dataoff,
 873                   u_int16_t l3num,
 874                   u_int8_t protonum,
 875                   struct nf_conntrack_l3proto *l3proto,
 876                   struct nf_conntrack_l4proto *l4proto,
 877                   int *set_reply,
 878                   enum ip_conntrack_info *ctinfo)
 879 {
 880         struct nf_conntrack_tuple tuple;
 881         struct nf_conntrack_tuple_hash *h;
 882         struct nf_conn *ct;
 883         u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
 884         u32 hash;
 885
 886         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 887                              dataoff, l3num, protonum, &tuple, l3proto,
 888                              l4proto)) {
 889                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 890                 return NULL;
 891         }
 892
 893         /* look for tuple match */
 894         hash = hash_conntrack_raw(&tuple, zone);
 895         h = __nf_conntrack_find_get(net, zone, &tuple, hash);
 896         if (!h) {
 897                 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto,
 898                                    skb, dataoff, hash);
 899                 if (!h)
 900                         return NULL;
 901                 if (IS_ERR(h))
 902                         return (void *)h;
 903         }
 904         ct = nf_ct_tuplehash_to_ctrack(h);
 905
 906         /* It exists; we have (non-exclusive) reference. */
 907         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 908                 *ctinfo = IP_CT_ESTABLISHED_REPLY;
 909                 /* Please set reply bit if this packet OK */
 910                 *set_reply = 1;
 911         } else {
 912                 /* Once we've had two way comms, always ESTABLISHED. */
 913                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 914                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 915                         *ctinfo = IP_CT_ESTABLISHED;
 916                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 917                         pr_debug("nf_conntrack_in: related packet for %p\n",
 918                                  ct);
 919                         *ctinfo = IP_CT_RELATED;
 920                 } else {
 921                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 922                         *ctinfo = IP_CT_NEW;
 923                 }
 924                 *set_reply = 0;
 925         }
 926         skb->nfct = &ct->ct_general;
 927         skb->nfctinfo = *ctinfo;
 928         return ct;
 929 }
 930
 931 unsigned int
 932 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 933                 struct sk_buff *skb)
 934 {
 935         struct nf_conn *ct, *tmpl = NULL;
 936         enum ip_conntrack_info ctinfo;
 937         struct nf_conntrack_l3proto *l3proto;
 938         struct nf_conntrack_l4proto *l4proto;
 939         unsigned int *timeouts;
 940         unsigned int dataoff;
 941         u_int8_t protonum;
 942         int set_reply = 0;
 943         int ret;
 944
 945         if (skb->nfct) {
 946                 /* Previously seen (loopback or untracked)?  Ignore. */
 947                 tmpl = (struct nf_conn *)skb->nfct;
 948                 if (!nf_ct_is_template(tmpl)) {
 949                         NF_CT_STAT_INC_ATOMIC(net, ignore);
 950                         return NF_ACCEPT;
 951                 }
 952                 skb->nfct = NULL;
 953         }
 954
 955         /* rcu_read_lock()ed by nf_hook_slow */
 956         l3proto = __nf_ct_l3proto_find(pf);
 957         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 958                                    &dataoff, &protonum);
 959         if (ret <= 0) {
 960                 pr_debug("not prepared to track yet or error occurred\n");
 961                 NF_CT_STAT_INC_ATOMIC(net, error);
 962                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 963                 ret = -ret;
 964                 goto out;
 965         }
 966
 967         l4proto = __nf_ct_l4proto_find(pf, protonum);
 968
 969         /* It may be an special packet, error, unclean...
 970          * inverse of the return code tells to the netfilter
 971          * core what to do with the packet. */
 972         if (l4proto->error != NULL) {
 973                 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo,
 974                                      pf, hooknum);
 975                 if (ret <= 0) {
 976                         NF_CT_STAT_INC_ATOMIC(net, error);
 977                         NF_CT_STAT_INC_ATOMIC(net, invalid);
 978                         ret = -ret;
 979                         goto out;
 980                 }
 981                 /* ICMP[v6] protocol trackers may assign one conntrack. */
 982                 if (skb->nfct)
 983                         goto out;
 984         }
 985
 986         ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum,
 987                                l3proto, l4proto, &set_reply, &ctinfo);
 988         if (!ct) {
 989                 /* Not valid part of a connection */
 990                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 991                 ret = NF_ACCEPT;
 992                 goto out;
 993         }
 994
 995         if (IS_ERR(ct)) {
 996                 /* Too stressed to deal. */
 997                 NF_CT_STAT_INC_ATOMIC(net, drop);
 998                 ret = NF_DROP;
 999                 goto out;
1000         }
1001
1002         NF_CT_ASSERT(skb->nfct);
1003
1004         /* Decide what timeout policy we want to apply to this flow. */
1005         timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
1006
1007         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
1008         if (ret <= 0) {
1009                 /* Invalid: inverse of the return code tells
1010                  * the netfilter core what to do */
1011                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1012                 nf_conntrack_put(skb->nfct);
1013                 skb->nfct = NULL;
1014                 NF_CT_STAT_INC_ATOMIC(net, invalid);
1015                 if (ret == -NF_DROP)
1016                         NF_CT_STAT_INC_ATOMIC(net, drop);
1017                 ret = -ret;
1018                 goto out;
1019         }
1020
1021         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1022                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1023 out:
1024         if (tmpl) {
1025                 /* Special case: we have to repeat this hook, assign the
1026                  * template again to this packet. We assume that this packet
1027                  * has no conntrack assigned. This is used by nf_ct_tcp. */
1028                 if (ret == NF_REPEAT)
1029                         skb->nfct = (struct nf_conntrack *)tmpl;
1030                 else
1031                         nf_ct_put(tmpl);
1032         }
1033
1034         return ret;
1035 }
1036 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1037
1038 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
1039                           const struct nf_conntrack_tuple *orig)
1040 {
1041         bool ret;
1042
1043         rcu_read_lock();
1044         ret = nf_ct_invert_tuple(inverse, orig,
1045                                  __nf_ct_l3proto_find(orig->src.l3num),
1046                                  __nf_ct_l4proto_find(orig->src.l3num,
1047                                                       orig->dst.protonum));
1048         rcu_read_unlock();
1049         return ret;
1050 }
1051 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
1052
1053 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1054    implicitly racy: see __nf_conntrack_confirm */
1055 void nf_conntrack_alter_reply(struct nf_conn *ct,
1056                               const struct nf_conntrack_tuple *newreply)
1057 {
1058         struct nf_conn_help *help = nfct_help(ct);
1059
1060         /* Should be unconfirmed, so not in hash table yet */
1061         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
1062
1063         pr_debug("Altering reply tuple of %p to ", ct);
1064         nf_ct_dump_tuple(newreply);
1065
1066         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1067         if (ct->master || (help && !hlist_empty(&help->expectations)))
1068                 return;
1069
1070         rcu_read_lock();
1071         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1072         rcu_read_unlock();
1073 }
1074 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1075
1076 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1077 void __nf_ct_refresh_acct(struct nf_conn *ct,
1078                           enum ip_conntrack_info ctinfo,
1079                           const struct sk_buff *skb,
1080                           unsigned long extra_jiffies,
1081                           int do_acct)
1082 {
1083         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
1084         NF_CT_ASSERT(skb);
1085
1086         /* Only update if this is not a fixed timeout */
1087         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1088                 goto acct;
1089
1090         /* If not in hash table, timer will not be active yet */
1091         if (!nf_ct_is_confirmed(ct)) {
1092                 ct->timeout.expires = extra_jiffies;
1093         } else {
1094                 unsigned long newtime = jiffies + extra_jiffies;
1095
1096                 /* Only update the timeout if the new timeout is at least
1097                    HZ jiffies from the old timeout. Need del_timer for race
1098                    avoidance (may already be dying). */
1099                 if (newtime - ct->timeout.expires >= HZ)
1100                         mod_timer_pending(&ct->timeout, newtime);
1101         }
1102
1103 acct:
1104         if (do_acct) {
1105                 struct nf_conn_counter *acct;
1106
1107                 acct = nf_conn_acct_find(ct);
1108                 if (acct) {
1109                         atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1110                         atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes);
1111                 }
1112         }
1113 }
1114 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1115
1116 bool __nf_ct_kill_acct(struct nf_conn *ct,
1117                        enum ip_conntrack_info ctinfo,
1118                        const struct sk_buff *skb,
1119                        int do_acct)
1120 {
1121         if (do_acct) {
1122                 struct nf_conn_counter *acct;
1123
1124                 acct = nf_conn_acct_find(ct);
1125                 if (acct) {
1126                         atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets);
1127                         atomic64_add(skb->len - skb_network_offset(skb),
1128                                      &acct[CTINFO2DIR(ctinfo)].bytes);
1129                 }
1130         }
1131
1132         if (del_timer(&ct->timeout)) {
1133                 ct->timeout.function((unsigned long)ct);
1134                 return true;
1135         }
1136         return false;
1137 }
1138 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
1139
1140 #ifdef CONFIG_NF_CONNTRACK_ZONES
1141 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = {
1142         .len    = sizeof(struct nf_conntrack_zone),
1143         .align  = __alignof__(struct nf_conntrack_zone),
1144         .id     = NF_CT_EXT_ZONE,
1145 };
1146 #endif
1147
1148 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1149
1150 #include <linux/netfilter/nfnetlink.h>
1151 #include <linux/netfilter/nfnetlink_conntrack.h>
1152 #include <linux/mutex.h>
1153
1154 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
1155  * in ip_conntrack_core, since we don't want the protocols to autoload
1156  * or depend on ctnetlink */
1157 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1158                                const struct nf_conntrack_tuple *tuple)
1159 {
1160         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1161             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1162                 goto nla_put_failure;
1163         return 0;
1164
1165 nla_put_failure:
1166         return -1;
1167 }
1168 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1169
1170 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1171         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1172         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1173 };
1174 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1175
1176 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1177                                struct nf_conntrack_tuple *t)
1178 {
1179         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1180                 return -EINVAL;
1181
1182         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1183         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1184
1185         return 0;
1186 }
1187 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1188
1189 int nf_ct_port_nlattr_tuple_size(void)
1190 {
1191         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1192 }
1193 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1194 #endif
1195
1196 /* Used by ipt_REJECT and ip6t_REJECT. */
1197 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
1198 {
1199         struct nf_conn *ct;
1200         enum ip_conntrack_info ctinfo;
1201
1202         /* This ICMP is in reverse direction to the packet which caused it */
1203         ct = nf_ct_get(skb, &ctinfo);
1204         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1205                 ctinfo = IP_CT_RELATED_REPLY;
1206         else
1207                 ctinfo = IP_CT_RELATED;
1208
1209         /* Attach to new skbuff, and increment count */
1210         nskb->nfct = &ct->ct_general;
1211         nskb->nfctinfo = ctinfo;
1212         nf_conntrack_get(nskb->nfct);
1213 }
1214
1215 /* Bring out ya dead! */
1216 static struct nf_conn *
1217 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1218                 void *data, unsigned int *bucket)
1219 {
1220         struct nf_conntrack_tuple_hash *h;
1221         struct nf_conn *ct;
1222         struct hlist_nulls_node *n;
1223
1224         spin_lock_bh(&nf_conntrack_lock);
1225         for (; *bucket < net->ct.htable_size; (*bucket)++) {
1226                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1227                         if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
1228                                 continue;
1229                         ct = nf_ct_tuplehash_to_ctrack(h);
1230                         if (iter(ct, data))
1231                                 goto found;
1232                 }
1233         }
1234         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1235                 ct = nf_ct_tuplehash_to_ctrack(h);
1236                 if (iter(ct, data))
1237                         set_bit(IPS_DYING_BIT, &ct->status);
1238         }
1239         spin_unlock_bh(&nf_conntrack_lock);
1240         return NULL;
1241 found:
1242         atomic_inc(&ct->ct_general.use);
1243         spin_unlock_bh(&nf_conntrack_lock);
1244         return ct;
1245 }
1246
1247 void nf_ct_iterate_cleanup(struct net *net,
1248                            int (*iter)(struct nf_conn *i, void *data),
1249                            void *data)
1250 {
1251         struct nf_conn *ct;
1252         unsigned int bucket = 0;
1253
1254         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1255                 /* Time to push up daises... */
1256                 if (del_timer(&ct->timeout))
1257                         death_by_timeout((unsigned long)ct);
1258                 /* ... else the timer will get him soon. */
1259
1260                 nf_ct_put(ct);
1261         }
1262 }
1263 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1264
1265 struct __nf_ct_flush_report {
1266         u32 pid;
1267         int report;
1268 };
1269
1270 static int kill_report(struct nf_conn *i, void *data)
1271 {
1272         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1273         struct nf_conn_tstamp *tstamp;
1274
1275         tstamp = nf_conn_tstamp_find(i);
1276         if (tstamp && tstamp->stop == 0)
1277                 tstamp->stop = ktime_to_ns(ktime_get_real());
1278
1279         /* If we fail to deliver the event, death_by_timeout() will retry */
1280         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1281                                       fr->pid, fr->report) < 0)
1282                 return 1;
1283
1284         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1285         set_bit(IPS_DYING_BIT, &i->status);
1286         return 1;
1287 }
1288
1289 static int kill_all(struct nf_conn *i, void *data)
1290 {
1291         return 1;
1292 }
1293
1294 void nf_ct_free_hashtable(void *hash, unsigned int size)
1295 {
1296         if (is_vmalloc_addr(hash))
1297                 vfree(hash);
1298         else
1299                 free_pages((unsigned long)hash,
1300                            get_order(sizeof(struct hlist_head) * size));
1301 }
1302 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1303
1304 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1305 {
1306         struct __nf_ct_flush_report fr = {
1307                 .pid    = pid,
1308                 .report = report,
1309         };
1310         nf_ct_iterate_cleanup(net, kill_report, &fr);
1311 }
1312 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1313
1314 static void nf_ct_release_dying_list(struct net *net)
1315 {
1316         struct nf_conntrack_tuple_hash *h;
1317         struct nf_conn *ct;
1318         struct hlist_nulls_node *n;
1319
1320         spin_lock_bh(&nf_conntrack_lock);
1321         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1322                 ct = nf_ct_tuplehash_to_ctrack(h);
1323                 /* never fails to remove them, no listeners at this point */
1324                 nf_ct_kill(ct);
1325         }
1326         spin_unlock_bh(&nf_conntrack_lock);
1327 }
1328
1329 static int untrack_refs(void)
1330 {
1331         int cnt = 0, cpu;
1332
1333         for_each_possible_cpu(cpu) {
1334                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1335
1336                 cnt += atomic_read(&ct->ct_general.use) - 1;
1337         }
1338         return cnt;
1339 }
1340
1341 static void nf_conntrack_cleanup_init_net(void)
1342 {
1343         while (untrack_refs() > 0)
1344                 schedule();
1345
1346 #ifdef CONFIG_NF_CONNTRACK_ZONES
1347         nf_ct_extend_unregister(&nf_ct_zone_extend);
1348 #endif
1349 }
1350
1351 static void nf_conntrack_cleanup_net(struct net *net)
1352 {
1353  i_see_dead_people:
1354         nf_ct_iterate_cleanup(net, kill_all, NULL);
1355         nf_ct_release_dying_list(net);
1356         if (atomic_read(&net->ct.count) != 0) {
1357                 schedule();
1358                 goto i_see_dead_people;
1359         }
1360
1361         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1362         nf_conntrack_helper_fini(net);
1363         nf_conntrack_timeout_fini(net);
1364         nf_conntrack_ecache_fini(net);
1365         nf_conntrack_tstamp_fini(net);
1366         nf_conntrack_acct_fini(net);
1367         nf_conntrack_expect_fini(net);
1368         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1369         kfree(net->ct.slabname);
1370         free_percpu(net->ct.stat);
1371 }
1372
1373 /* Mishearing the voices in his head, our hero wonders how he's
1374    supposed to kill the mall. */
1375 void nf_conntrack_cleanup(struct net *net)
1376 {
1377         if (net_eq(net, &init_net))
1378                 RCU_INIT_POINTER(ip_ct_attach, NULL);
1379
1380         /* This makes sure all current packets have passed through
1381            netfilter framework.  Roll on, two-stage module
1382            delete... */
1383         synchronize_net();
1384         nf_conntrack_proto_fini(net);
1385         nf_conntrack_cleanup_net(net);
1386
1387         if (net_eq(net, &init_net)) {
1388                 RCU_INIT_POINTER(nf_ct_destroy, NULL);
1389                 nf_conntrack_cleanup_init_net();
1390         }
1391 }
1392
1393 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
1394 {
1395         struct hlist_nulls_head *hash;
1396         unsigned int nr_slots, i;
1397         size_t sz;
1398
1399         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1400         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1401         sz = nr_slots * sizeof(struct hlist_nulls_head);
1402         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1403                                         get_order(sz));
1404         if (!hash) {
1405                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1406                 hash = vzalloc(sz);
1407         }
1408
1409         if (hash && nulls)
1410                 for (i = 0; i < nr_slots; i++)
1411                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1412
1413         return hash;
1414 }
1415 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1416
1417 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1418 {
1419         int i, bucket;
1420         unsigned int hashsize, old_size;
1421         struct hlist_nulls_head *hash, *old_hash;
1422         struct nf_conntrack_tuple_hash *h;
1423         struct nf_conn *ct;
1424
1425         if (current->nsproxy->net_ns != &init_net)
1426                 return -EOPNOTSUPP;
1427
1428         /* On boot, we can set this without any fancy locking. */
1429         if (!nf_conntrack_htable_size)
1430                 return param_set_uint(val, kp);
1431
1432         hashsize = simple_strtoul(val, NULL, 0);
1433         if (!hashsize)
1434                 return -EINVAL;
1435
1436         hash = nf_ct_alloc_hashtable(&hashsize, 1);
1437         if (!hash)
1438                 return -ENOMEM;
1439
1440         /* Lookups in the old hash might happen in parallel, which means we
1441          * might get false negatives during connection lookup. New connections
1442          * created because of a false negative won't make it into the hash
1443          * though since that required taking the lock.
1444          */
1445         spin_lock_bh(&nf_conntrack_lock);
1446         for (i = 0; i < init_net.ct.htable_size; i++) {
1447                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1448                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1449                                         struct nf_conntrack_tuple_hash, hnnode);
1450                         ct = nf_ct_tuplehash_to_ctrack(h);
1451                         hlist_nulls_del_rcu(&h->hnnode);
1452                         bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct),
1453                                                   hashsize);
1454                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1455                 }
1456         }
1457         old_size = init_net.ct.htable_size;
1458         old_hash = init_net.ct.hash;
1459
1460         init_net.ct.htable_size = nf_conntrack_htable_size = hashsize;
1461         init_net.ct.hash = hash;
1462         spin_unlock_bh(&nf_conntrack_lock);
1463
1464         nf_ct_free_hashtable(old_hash, old_size);
1465         return 0;
1466 }
1467 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1468
1469 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1470                   &nf_conntrack_htable_size, 0600);
1471
1472 void nf_ct_untracked_status_or(unsigned long bits)
1473 {
1474         int cpu;
1475
1476         for_each_possible_cpu(cpu)
1477                 per_cpu(nf_conntrack_untracked, cpu).status |= bits;
1478 }
1479 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
1480
1481 static int nf_conntrack_init_init_net(void)
1482 {
1483         int max_factor = 8;
1484         int ret, cpu;
1485
1486         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1487          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1488         if (!nf_conntrack_htable_size) {
1489                 nf_conntrack_htable_size
1490                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1491                            / sizeof(struct hlist_head));
1492                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1493                         nf_conntrack_htable_size = 16384;
1494                 if (nf_conntrack_htable_size < 32)
1495                         nf_conntrack_htable_size = 32;
1496
1497                 /* Use a max. factor of four by default to get the same max as
1498                  * with the old struct list_heads. When a table size is given
1499                  * we use the old value of 8 to avoid reducing the max.
1500                  * entries. */
1501                 max_factor = 4;
1502         }
1503         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1504
1505         printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
1506                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1507                nf_conntrack_max);
1508 #ifdef CONFIG_NF_CONNTRACK_ZONES
1509         ret = nf_ct_extend_register(&nf_ct_zone_extend);
1510         if (ret < 0)
1511                 goto err_extend;
1512 #endif
1513         /* Set up fake conntrack: to never be deleted, not in any hashes */
1514         for_each_possible_cpu(cpu) {
1515                 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu);
1516                 write_pnet(&ct->ct_net, &init_net);
1517                 atomic_set(&ct->ct_general.use, 1);
1518         }
1519         /*  - and look it like as a confirmed connection */
1520         nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED);
1521         return 0;
1522
1523 #ifdef CONFIG_NF_CONNTRACK_ZONES
1524 err_extend:
1525 #endif
1526         return ret;
1527 }
1528
1529 /*
1530  * We need to use special "null" values, not used in hash table
1531  */
1532 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1533 #define DYING_NULLS_VAL         ((1<<30)+1)
1534
1535 static int nf_conntrack_init_net(struct net *net)
1536 {
1537         int ret;
1538
1539         atomic_set(&net->ct.count, 0);
1540         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1541         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1542         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1543         if (!net->ct.stat) {
1544                 ret = -ENOMEM;
1545                 goto err_stat;
1546         }
1547
1548         net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net);
1549         if (!net->ct.slabname) {
1550                 ret = -ENOMEM;
1551                 goto err_slabname;
1552         }
1553
1554         net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
1555                                                         sizeof(struct nf_conn), 0,
1556                                                         SLAB_DESTROY_BY_RCU, NULL);
1557         if (!net->ct.nf_conntrack_cachep) {
1558                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1559                 ret = -ENOMEM;
1560                 goto err_cache;
1561         }
1562
1563         net->ct.htable_size = nf_conntrack_htable_size;
1564         net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1);
1565         if (!net->ct.hash) {
1566                 ret = -ENOMEM;
1567                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1568                 goto err_hash;
1569         }
1570         ret = nf_conntrack_expect_init(net);
1571         if (ret < 0)
1572                 goto err_expect;
1573         ret = nf_conntrack_acct_init(net);
1574         if (ret < 0)
1575                 goto err_acct;
1576         ret = nf_conntrack_tstamp_init(net);
1577         if (ret < 0)
1578                 goto err_tstamp;
1579         ret = nf_conntrack_ecache_init(net);
1580         if (ret < 0)
1581                 goto err_ecache;
1582         ret = nf_conntrack_timeout_init(net);
1583         if (ret < 0)
1584                 goto err_timeout;
1585         ret = nf_conntrack_helper_init(net);
1586         if (ret < 0)
1587                 goto err_helper;
1588         return 0;
1589 err_helper:
1590         nf_conntrack_timeout_fini(net);
1591 err_timeout:
1592         nf_conntrack_ecache_fini(net);
1593 err_ecache:
1594         nf_conntrack_tstamp_fini(net);
1595 err_tstamp:
1596         nf_conntrack_acct_fini(net);
1597 err_acct:
1598         nf_conntrack_expect_fini(net);
1599 err_expect:
1600         nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
1601 err_hash:
1602         kmem_cache_destroy(net->ct.nf_conntrack_cachep);
1603 err_cache:
1604         kfree(net->ct.slabname);
1605 err_slabname:
1606         free_percpu(net->ct.stat);
1607 err_stat:
1608         return ret;
1609 }
1610
1611 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
1612                         enum ip_conntrack_dir dir,
1613                         u32 seq);
1614 EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
1615
1616 int nf_conntrack_init(struct net *net)
1617 {
1618         int ret;
1619
1620         if (net_eq(net, &init_net)) {
1621                 ret = nf_conntrack_init_init_net();
1622                 if (ret < 0)
1623                         goto out_init_net;
1624         }
1625         ret = nf_conntrack_proto_init(net);
1626         if (ret < 0)
1627                 goto out_proto;
1628         ret = nf_conntrack_init_net(net);
1629         if (ret < 0)
1630                 goto out_net;
1631
1632         if (net_eq(net, &init_net)) {
1633                 /* For use by REJECT target */
1634                 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
1635                 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
1636
1637                 /* Howto get NAT offsets */
1638                 RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
1639         }
1640         return 0;
1641
1642 out_net:
1643         nf_conntrack_proto_fini(net);
1644 out_proto:
1645         if (net_eq(net, &init_net))
1646                 nf_conntrack_cleanup_init_net();
1647 out_init_net:
1648         return ret;
1649 }