SAFE public projects git trees. - safe/jmp/linux-2.6/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/rculist_nulls.h>
  34
  35 #include <net/netfilter/nf_conntrack.h>
  36 #include <net/netfilter/nf_conntrack_l3proto.h>
  37 #include <net/netfilter/nf_conntrack_l4proto.h>
  38 #include <net/netfilter/nf_conntrack_expect.h>
  39 #include <net/netfilter/nf_conntrack_helper.h>
  40 #include <net/netfilter/nf_conntrack_core.h>
  41 #include <net/netfilter/nf_conntrack_extend.h>
  42 #include <net/netfilter/nf_conntrack_acct.h>
  43 #include <net/netfilter/nf_conntrack_ecache.h>
  44 #include <net/netfilter/nf_nat.h>
  45 #include <net/netfilter/nf_nat_core.h>
  46
  47 #define NF_CONNTRACK_VERSION    "0.5.0"
  48
  49 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
  50                                       enum nf_nat_manip_type manip,
  51                                       const struct nlattr *attr) __read_mostly;
  52 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
  53
  54 DEFINE_SPINLOCK(nf_conntrack_lock);
  55 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
  56
  57 unsigned int nf_conntrack_htable_size __read_mostly;
  58 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
  59
  60 unsigned int nf_conntrack_max __read_mostly;
  61 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  62
  63 struct nf_conn nf_conntrack_untracked __read_mostly;
  64 EXPORT_SYMBOL_GPL(nf_conntrack_untracked);
  65
  66 static struct kmem_cache *nf_conntrack_cachep __read_mostly;
  67
  68 static int nf_conntrack_hash_rnd_initted;
  69 static unsigned int nf_conntrack_hash_rnd;
  70
  71 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
  72                                   unsigned int size, unsigned int rnd)
  73 {
  74         unsigned int n;
  75         u_int32_t h;
  76
  77         /* The direction must be ignored, so we hash everything up to the
  78          * destination ports (which is a multiple of 4) and treat the last
  79          * three bytes manually.
  80          */
  81         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
  82         h = jhash2((u32 *)tuple, n,
  83                    rnd ^ (((__force __u16)tuple->dst.u.all << 16) |
  84                           tuple->dst.protonum));
  85
  86         return ((u64)h * size) >> 32;
  87 }
  88
  89 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
  90 {
  91         return __hash_conntrack(tuple, nf_conntrack_htable_size,
  92                                 nf_conntrack_hash_rnd);
  93 }
  94
  95 bool
  96 nf_ct_get_tuple(const struct sk_buff *skb,
  97                 unsigned int nhoff,
  98                 unsigned int dataoff,
  99                 u_int16_t l3num,
 100                 u_int8_t protonum,
 101                 struct nf_conntrack_tuple *tuple,
 102                 const struct nf_conntrack_l3proto *l3proto,
 103                 const struct nf_conntrack_l4proto *l4proto)
 104 {
 105         memset(tuple, 0, sizeof(*tuple));
 106
 107         tuple->src.l3num = l3num;
 108         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 109                 return false;
 110
 111         tuple->dst.protonum = protonum;
 112         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 113
 114         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 115 }
 116 EXPORT_SYMBOL_GPL(nf_ct_get_tuple);
 117
 118 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 119                        u_int16_t l3num, struct nf_conntrack_tuple *tuple)
 120 {
 121         struct nf_conntrack_l3proto *l3proto;
 122         struct nf_conntrack_l4proto *l4proto;
 123         unsigned int protoff;
 124         u_int8_t protonum;
 125         int ret;
 126
 127         rcu_read_lock();
 128
 129         l3proto = __nf_ct_l3proto_find(l3num);
 130         ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum);
 131         if (ret != NF_ACCEPT) {
 132                 rcu_read_unlock();
 133                 return false;
 134         }
 135
 136         l4proto = __nf_ct_l4proto_find(l3num, protonum);
 137
 138         ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple,
 139                               l3proto, l4proto);
 140
 141         rcu_read_unlock();
 142         return ret;
 143 }
 144 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 145
 146 bool
 147 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 148                    const struct nf_conntrack_tuple *orig,
 149                    const struct nf_conntrack_l3proto *l3proto,
 150                    const struct nf_conntrack_l4proto *l4proto)
 151 {
 152         memset(inverse, 0, sizeof(*inverse));
 153
 154         inverse->src.l3num = orig->src.l3num;
 155         if (l3proto->invert_tuple(inverse, orig) == 0)
 156                 return false;
 157
 158         inverse->dst.dir = !orig->dst.dir;
 159
 160         inverse->dst.protonum = orig->dst.protonum;
 161         return l4proto->invert_tuple(inverse, orig);
 162 }
 163 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 164
 165 static void
 166 clean_from_lists(struct nf_conn *ct)
 167 {
 168         pr_debug("clean_from_lists(%p)\n", ct);
 169         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 170         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 171
 172         /* Destroy all pending expectations */
 173         nf_ct_remove_expectations(ct);
 174 }
 175
 176 static void
 177 destroy_conntrack(struct nf_conntrack *nfct)
 178 {
 179         struct nf_conn *ct = (struct nf_conn *)nfct;
 180         struct net *net = nf_ct_net(ct);
 181         struct nf_conntrack_l4proto *l4proto;
 182
 183         pr_debug("destroy_conntrack(%p)\n", ct);
 184         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 185         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 186
 187         /* To make sure we don't get any weird locking issues here:
 188          * destroy_conntrack() MUST NOT be called with a write lock
 189          * to nf_conntrack_lock!!! -HW */
 190         rcu_read_lock();
 191         l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 192         if (l4proto && l4proto->destroy)
 193                 l4proto->destroy(ct);
 194
 195         rcu_read_unlock();
 196
 197         spin_lock_bh(&nf_conntrack_lock);
 198         /* Expectations will have been removed in clean_from_lists,
 199          * except TFTP can create an expectation on the first packet,
 200          * before connection is in the list, so we need to clean here,
 201          * too. */
 202         nf_ct_remove_expectations(ct);
 203
 204         /* We overload first tuple to link into unconfirmed list. */
 205         if (!nf_ct_is_confirmed(ct)) {
 206                 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 207                 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 208         }
 209
 210         NF_CT_STAT_INC(net, delete);
 211         spin_unlock_bh(&nf_conntrack_lock);
 212
 213         if (ct->master)
 214                 nf_ct_put(ct->master);
 215
 216         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 217         nf_conntrack_free(ct);
 218 }
 219
 220 void nf_ct_delete_from_lists(struct nf_conn *ct)
 221 {
 222         struct net *net = nf_ct_net(ct);
 223
 224         nf_ct_helper_destroy(ct);
 225         spin_lock_bh(&nf_conntrack_lock);
 226         /* Inside lock so preempt is disabled on module removal path.
 227          * Otherwise we can get spurious warnings. */
 228         NF_CT_STAT_INC(net, delete_list);
 229         clean_from_lists(ct);
 230         spin_unlock_bh(&nf_conntrack_lock);
 231 }
 232 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
 233
 234 static void death_by_event(unsigned long ul_conntrack)
 235 {
 236         struct nf_conn *ct = (void *)ul_conntrack;
 237         struct net *net = nf_ct_net(ct);
 238
 239         if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
 240                 /* bad luck, let's retry again */
 241                 ct->timeout.expires = jiffies +
 242                         (random32() % net->ct.sysctl_events_retry_timeout);
 243                 add_timer(&ct->timeout);
 244                 return;
 245         }
 246         /* we've got the event delivered, now it's dying */
 247         set_bit(IPS_DYING_BIT, &ct->status);
 248         spin_lock(&nf_conntrack_lock);
 249         hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 250         spin_unlock(&nf_conntrack_lock);
 251         nf_ct_put(ct);
 252 }
 253
 254 void nf_ct_insert_dying_list(struct nf_conn *ct)
 255 {
 256         struct net *net = nf_ct_net(ct);
 257
 258         /* add this conntrack to the dying list */
 259         spin_lock_bh(&nf_conntrack_lock);
 260         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 261                              &net->ct.dying);
 262         spin_unlock_bh(&nf_conntrack_lock);
 263         /* set a new timer to retry event delivery */
 264         setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
 265         ct->timeout.expires = jiffies +
 266                 (random32() % net->ct.sysctl_events_retry_timeout);
 267         add_timer(&ct->timeout);
 268 }
 269 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
 270
 271 static void death_by_timeout(unsigned long ul_conntrack)
 272 {
 273         struct nf_conn *ct = (void *)ul_conntrack;
 274
 275         if (!test_bit(IPS_DYING_BIT, &ct->status) &&
 276             unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
 277                 /* destroy event was not delivered */
 278                 nf_ct_delete_from_lists(ct);
 279                 nf_ct_insert_dying_list(ct);
 280                 return;
 281         }
 282         set_bit(IPS_DYING_BIT, &ct->status);
 283         nf_ct_delete_from_lists(ct);
 284         nf_ct_put(ct);
 285 }
 286
 287 /*
 288  * Warning :
 289  * - Caller must take a reference on returned object
 290  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 291  * OR
 292  * - Caller must lock nf_conntrack_lock before calling this function
 293  */
 294 struct nf_conntrack_tuple_hash *
 295 __nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple)
 296 {
 297         struct nf_conntrack_tuple_hash *h;
 298         struct hlist_nulls_node *n;
 299         unsigned int hash = hash_conntrack(tuple);
 300
 301         /* Disable BHs the entire time since we normally need to disable them
 302          * at least once for the stats anyway.
 303          */
 304         local_bh_disable();
 305 begin:
 306         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 307                 if (nf_ct_tuple_equal(tuple, &h->tuple)) {
 308                         NF_CT_STAT_INC(net, found);
 309                         local_bh_enable();
 310                         return h;
 311                 }
 312                 NF_CT_STAT_INC(net, searched);
 313         }
 314         /*
 315          * if the nulls value we got at the end of this lookup is
 316          * not the expected one, we must restart lookup.
 317          * We probably met an item that was moved to another chain.
 318          */
 319         if (get_nulls_value(n) != hash)
 320                 goto begin;
 321         local_bh_enable();
 322
 323         return NULL;
 324 }
 325 EXPORT_SYMBOL_GPL(__nf_conntrack_find);
 326
 327 /* Find a connection corresponding to a tuple. */
 328 struct nf_conntrack_tuple_hash *
 329 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple)
 330 {
 331         struct nf_conntrack_tuple_hash *h;
 332         struct nf_conn *ct;
 333
 334         rcu_read_lock();
 335 begin:
 336         h = __nf_conntrack_find(net, tuple);
 337         if (h) {
 338                 ct = nf_ct_tuplehash_to_ctrack(h);
 339                 if (unlikely(nf_ct_is_dying(ct) ||
 340                              !atomic_inc_not_zero(&ct->ct_general.use)))
 341                         h = NULL;
 342                 else {
 343                         if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
 344                                 nf_ct_put(ct);
 345                                 goto begin;
 346                         }
 347                 }
 348         }
 349         rcu_read_unlock();
 350
 351         return h;
 352 }
 353 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 354
 355 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 356                                        unsigned int hash,
 357                                        unsigned int repl_hash)
 358 {
 359         struct net *net = nf_ct_net(ct);
 360
 361         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 362                            &net->ct.hash[hash]);
 363         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 364                            &net->ct.hash[repl_hash]);
 365 }
 366
 367 void nf_conntrack_hash_insert(struct nf_conn *ct)
 368 {
 369         unsigned int hash, repl_hash;
 370
 371         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 372         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 373
 374         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 375 }
 376 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert);
 377
 378 /* Confirm a connection given skb; places it in hash table */
 379 int
 380 __nf_conntrack_confirm(struct sk_buff *skb)
 381 {
 382         unsigned int hash, repl_hash;
 383         struct nf_conntrack_tuple_hash *h;
 384         struct nf_conn *ct;
 385         struct nf_conn_help *help;
 386         struct hlist_nulls_node *n;
 387         enum ip_conntrack_info ctinfo;
 388         struct net *net;
 389
 390         ct = nf_ct_get(skb, &ctinfo);
 391         net = nf_ct_net(ct);
 392
 393         /* ipt_REJECT uses nf_conntrack_attach to attach related
 394            ICMP/TCP RST packets in other direction.  Actual packet
 395            which created connection will be IP_CT_NEW or for an
 396            expected connection, IP_CT_RELATED. */
 397         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 398                 return NF_ACCEPT;
 399
 400         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 401         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 402
 403         /* We're not in hash table, and we refuse to set up related
 404            connections for unconfirmed conns.  But packet copies and
 405            REJECT will give spurious warnings here. */
 406         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 407
 408         /* No external references means noone else could have
 409            confirmed us. */
 410         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 411         pr_debug("Confirming conntrack %p\n", ct);
 412
 413         spin_lock_bh(&nf_conntrack_lock);
 414
 415         /* See if there's one in the list already, including reverse:
 416            NAT could have grabbed it without realizing, since we're
 417            not in the hash.  If there is, we lost race. */
 418         hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode)
 419                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 420                                       &h->tuple))
 421                         goto out;
 422         hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
 423                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 424                                       &h->tuple))
 425                         goto out;
 426
 427         /* Remove from unconfirmed list */
 428         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 429
 430         /* Timer relative to confirmation time, not original
 431            setting time, otherwise we'd get timer wrap in
 432            weird delay cases. */
 433         ct->timeout.expires += jiffies;
 434         add_timer(&ct->timeout);
 435         atomic_inc(&ct->ct_general.use);
 436         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 437
 438         /* Since the lookup is lockless, hash insertion must be done after
 439          * starting the timer and setting the CONFIRMED bit. The RCU barriers
 440          * guarantee that no other CPU can find the conntrack before the above
 441          * stores are visible.
 442          */
 443         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 444         NF_CT_STAT_INC(net, insert);
 445         spin_unlock_bh(&nf_conntrack_lock);
 446
 447         help = nfct_help(ct);
 448         if (help && help->helper)
 449                 nf_conntrack_event_cache(IPCT_HELPER, ct);
 450
 451         nf_conntrack_event_cache(master_ct(ct) ?
 452                                  IPCT_RELATED : IPCT_NEW, ct);
 453         return NF_ACCEPT;
 454
 455 out:
 456         NF_CT_STAT_INC(net, insert_failed);
 457         spin_unlock_bh(&nf_conntrack_lock);
 458         return NF_DROP;
 459 }
 460 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
 461
 462 /* Returns true if a connection correspondings to the tuple (required
 463    for NAT). */
 464 int
 465 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 466                          const struct nf_conn *ignored_conntrack)
 467 {
 468         struct net *net = nf_ct_net(ignored_conntrack);
 469         struct nf_conntrack_tuple_hash *h;
 470         struct hlist_nulls_node *n;
 471         unsigned int hash = hash_conntrack(tuple);
 472
 473         /* Disable BHs the entire time since we need to disable them at
 474          * least once for the stats anyway.
 475          */
 476         rcu_read_lock_bh();
 477         hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) {
 478                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 479                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 480                         NF_CT_STAT_INC(net, found);
 481                         rcu_read_unlock_bh();
 482                         return 1;
 483                 }
 484                 NF_CT_STAT_INC(net, searched);
 485         }
 486         rcu_read_unlock_bh();
 487
 488         return 0;
 489 }
 490 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
 491
 492 #define NF_CT_EVICTION_RANGE    8
 493
 494 /* There's a small race here where we may free a just-assured
 495    connection.  Too bad: we're in trouble anyway. */
 496 static noinline int early_drop(struct net *net, unsigned int hash)
 497 {
 498         /* Use oldest entry, which is roughly LRU */
 499         struct nf_conntrack_tuple_hash *h;
 500         struct nf_conn *ct = NULL, *tmp;
 501         struct hlist_nulls_node *n;
 502         unsigned int i, cnt = 0;
 503         int dropped = 0;
 504
 505         rcu_read_lock();
 506         for (i = 0; i < nf_conntrack_htable_size; i++) {
 507                 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash],
 508                                          hnnode) {
 509                         tmp = nf_ct_tuplehash_to_ctrack(h);
 510                         if (!test_bit(IPS_ASSURED_BIT, &tmp->status))
 511                                 ct = tmp;
 512                         cnt++;
 513                 }
 514
 515                 if (ct && unlikely(nf_ct_is_dying(ct) ||
 516                                    !atomic_inc_not_zero(&ct->ct_general.use)))
 517                         ct = NULL;
 518                 if (ct || cnt >= NF_CT_EVICTION_RANGE)
 519                         break;
 520                 hash = (hash + 1) % nf_conntrack_htable_size;
 521         }
 522         rcu_read_unlock();
 523
 524         if (!ct)
 525                 return dropped;
 526
 527         if (del_timer(&ct->timeout)) {
 528                 death_by_timeout((unsigned long)ct);
 529                 dropped = 1;
 530                 NF_CT_STAT_INC_ATOMIC(net, early_drop);
 531         }
 532         nf_ct_put(ct);
 533         return dropped;
 534 }
 535
 536 struct nf_conn *nf_conntrack_alloc(struct net *net,
 537                                    const struct nf_conntrack_tuple *orig,
 538                                    const struct nf_conntrack_tuple *repl,
 539                                    gfp_t gfp)
 540 {
 541         struct nf_conn *ct;
 542
 543         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 544                 get_random_bytes(&nf_conntrack_hash_rnd,
 545                                 sizeof(nf_conntrack_hash_rnd));
 546                 nf_conntrack_hash_rnd_initted = 1;
 547         }
 548
 549         /* We don't want any race condition at early drop stage */
 550         atomic_inc(&net->ct.count);
 551
 552         if (nf_conntrack_max &&
 553             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
 554                 unsigned int hash = hash_conntrack(orig);
 555                 if (!early_drop(net, hash)) {
 556                         atomic_dec(&net->ct.count);
 557                         if (net_ratelimit())
 558                                 printk(KERN_WARNING
 559                                        "nf_conntrack: table full, dropping"
 560                                        " packet.\n");
 561                         return ERR_PTR(-ENOMEM);
 562                 }
 563         }
 564
 565         /*
 566          * Do not use kmem_cache_zalloc(), as this cache uses
 567          * SLAB_DESTROY_BY_RCU.
 568          */
 569         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
 570         if (ct == NULL) {
 571                 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
 572                 atomic_dec(&net->ct.count);
 573                 return ERR_PTR(-ENOMEM);
 574         }
 575         /*
 576          * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
 577          * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
 578          */
 579         memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
 580                sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
 581         spin_lock_init(&ct->lock);
 582         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 583         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
 584         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 585         ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL;
 586         /* Don't set timer yet: wait for confirmation */
 587         setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 588 #ifdef CONFIG_NET_NS
 589         ct->ct_net = net;
 590 #endif
 591
 592         /*
 593          * changes to lookup keys must be done before setting refcnt to 1
 594          */
 595         smp_wmb();
 596         atomic_set(&ct->ct_general.use, 1);
 597         return ct;
 598 }
 599 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
 600
 601 void nf_conntrack_free(struct nf_conn *ct)
 602 {
 603         struct net *net = nf_ct_net(ct);
 604
 605         nf_ct_ext_destroy(ct);
 606         atomic_dec(&net->ct.count);
 607         nf_ct_ext_free(ct);
 608         kmem_cache_free(nf_conntrack_cachep, ct);
 609 }
 610 EXPORT_SYMBOL_GPL(nf_conntrack_free);
 611
 612 /* Allocate a new conntrack: we return -ENOMEM if classification
 613    failed due to stress.  Otherwise it really is unclassifiable. */
 614 static struct nf_conntrack_tuple_hash *
 615 init_conntrack(struct net *net,
 616                const struct nf_conntrack_tuple *tuple,
 617                struct nf_conntrack_l3proto *l3proto,
 618                struct nf_conntrack_l4proto *l4proto,
 619                struct sk_buff *skb,
 620                unsigned int dataoff)
 621 {
 622         struct nf_conn *ct;
 623         struct nf_conn_help *help;
 624         struct nf_conntrack_tuple repl_tuple;
 625         struct nf_conntrack_expect *exp;
 626
 627         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 628                 pr_debug("Can't invert tuple.\n");
 629                 return NULL;
 630         }
 631
 632         ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC);
 633         if (IS_ERR(ct)) {
 634                 pr_debug("Can't allocate conntrack.\n");
 635                 return (struct nf_conntrack_tuple_hash *)ct;
 636         }
 637
 638         if (!l4proto->new(ct, skb, dataoff)) {
 639                 nf_conntrack_free(ct);
 640                 pr_debug("init conntrack: can't track with proto module\n");
 641                 return NULL;
 642         }
 643
 644         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
 645         nf_ct_ecache_ext_add(ct, GFP_ATOMIC);
 646
 647         spin_lock_bh(&nf_conntrack_lock);
 648         exp = nf_ct_find_expectation(net, tuple);
 649         if (exp) {
 650                 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n",
 651                          ct, exp);
 652                 /* Welcome, Mr. Bond.  We've been expecting you... */
 653                 __set_bit(IPS_EXPECTED_BIT, &ct->status);
 654                 ct->master = exp->master;
 655                 if (exp->helper) {
 656                         help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
 657                         if (help)
 658                                 rcu_assign_pointer(help->helper, exp->helper);
 659                 }
 660
 661 #ifdef CONFIG_NF_CONNTRACK_MARK
 662                 ct->mark = exp->master->mark;
 663 #endif
 664 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 665                 ct->secmark = exp->master->secmark;
 666 #endif
 667                 nf_conntrack_get(&ct->master->ct_general);
 668                 NF_CT_STAT_INC(net, expect_new);
 669         } else {
 670                 __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
 671                 NF_CT_STAT_INC(net, new);
 672         }
 673
 674         /* Overload tuple linked list to put us in unconfirmed list. */
 675         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 676                        &net->ct.unconfirmed);
 677
 678         spin_unlock_bh(&nf_conntrack_lock);
 679
 680         if (exp) {
 681                 if (exp->expectfn)
 682                         exp->expectfn(ct, exp);
 683                 nf_ct_expect_put(exp);
 684         }
 685
 686         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
 687 }
 688
 689 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 690 static inline struct nf_conn *
 691 resolve_normal_ct(struct net *net,
 692                   struct sk_buff *skb,
 693                   unsigned int dataoff,
 694                   u_int16_t l3num,
 695                   u_int8_t protonum,
 696                   struct nf_conntrack_l3proto *l3proto,
 697                   struct nf_conntrack_l4proto *l4proto,
 698                   int *set_reply,
 699                   enum ip_conntrack_info *ctinfo)
 700 {
 701         struct nf_conntrack_tuple tuple;
 702         struct nf_conntrack_tuple_hash *h;
 703         struct nf_conn *ct;
 704
 705         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
 706                              dataoff, l3num, protonum, &tuple, l3proto,
 707                              l4proto)) {
 708                 pr_debug("resolve_normal_ct: Can't get tuple\n");
 709                 return NULL;
 710         }
 711
 712         /* look for tuple match */
 713         h = nf_conntrack_find_get(net, &tuple);
 714         if (!h) {
 715                 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff);
 716                 if (!h)
 717                         return NULL;
 718                 if (IS_ERR(h))
 719                         return (void *)h;
 720         }
 721         ct = nf_ct_tuplehash_to_ctrack(h);
 722
 723         /* It exists; we have (non-exclusive) reference. */
 724         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 725                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 726                 /* Please set reply bit if this packet OK */
 727                 *set_reply = 1;
 728         } else {
 729                 /* Once we've had two way comms, always ESTABLISHED. */
 730                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 731                         pr_debug("nf_conntrack_in: normal packet for %p\n", ct);
 732                         *ctinfo = IP_CT_ESTABLISHED;
 733                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 734                         pr_debug("nf_conntrack_in: related packet for %p\n",
 735                                  ct);
 736                         *ctinfo = IP_CT_RELATED;
 737                 } else {
 738                         pr_debug("nf_conntrack_in: new packet for %p\n", ct);
 739                         *ctinfo = IP_CT_NEW;
 740                 }
 741                 *set_reply = 0;
 742         }
 743         skb->nfct = &ct->ct_general;
 744         skb->nfctinfo = *ctinfo;
 745         return ct;
 746 }
 747
 748 unsigned int
 749 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 750                 struct sk_buff *skb)
 751 {
 752         struct nf_conn *ct;
 753         enum ip_conntrack_info ctinfo;
 754         struct nf_conntrack_l3proto *l3proto;
 755         struct nf_conntrack_l4proto *l4proto;
 756         unsigned int dataoff;
 757         u_int8_t protonum;
 758         int set_reply = 0;
 759         int ret;
 760
 761         /* Previously seen (loopback or untracked)?  Ignore. */
 762         if (skb->nfct) {
 763                 NF_CT_STAT_INC_ATOMIC(net, ignore);
 764                 return NF_ACCEPT;
 765         }
 766
 767         /* rcu_read_lock()ed by nf_hook_slow */
 768         l3proto = __nf_ct_l3proto_find(pf);
 769         ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 770                                    &dataoff, &protonum);
 771         if (ret <= 0) {
 772                 pr_debug("not prepared to track yet or error occured\n");
 773                 NF_CT_STAT_INC_ATOMIC(net, error);
 774                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 775                 return -ret;
 776         }
 777
 778         l4proto = __nf_ct_l4proto_find(pf, protonum);
 779
 780         /* It may be an special packet, error, unclean...
 781          * inverse of the return code tells to the netfilter
 782          * core what to do with the packet. */
 783         if (l4proto->error != NULL) {
 784                 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum);
 785                 if (ret <= 0) {
 786                         NF_CT_STAT_INC_ATOMIC(net, error);
 787                         NF_CT_STAT_INC_ATOMIC(net, invalid);
 788                         return -ret;
 789                 }
 790         }
 791
 792         ct = resolve_normal_ct(net, skb, dataoff, pf, protonum,
 793                                l3proto, l4proto, &set_reply, &ctinfo);
 794         if (!ct) {
 795                 /* Not valid part of a connection */
 796                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 797                 return NF_ACCEPT;
 798         }
 799
 800         if (IS_ERR(ct)) {
 801                 /* Too stressed to deal. */
 802                 NF_CT_STAT_INC_ATOMIC(net, drop);
 803                 return NF_DROP;
 804         }
 805
 806         NF_CT_ASSERT(skb->nfct);
 807
 808         ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum);
 809         if (ret <= 0) {
 810                 /* Invalid: inverse of the return code tells
 811                  * the netfilter core what to do */
 812                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
 813                 nf_conntrack_put(skb->nfct);
 814                 skb->nfct = NULL;
 815                 NF_CT_STAT_INC_ATOMIC(net, invalid);
 816                 if (ret == -NF_DROP)
 817                         NF_CT_STAT_INC_ATOMIC(net, drop);
 818                 return -ret;
 819         }
 820
 821         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 822                 nf_conntrack_event_cache(IPCT_STATUS, ct);
 823
 824         return ret;
 825 }
 826 EXPORT_SYMBOL_GPL(nf_conntrack_in);
 827
 828 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 829                           const struct nf_conntrack_tuple *orig)
 830 {
 831         bool ret;
 832
 833         rcu_read_lock();
 834         ret = nf_ct_invert_tuple(inverse, orig,
 835                                  __nf_ct_l3proto_find(orig->src.l3num),
 836                                  __nf_ct_l4proto_find(orig->src.l3num,
 837                                                       orig->dst.protonum));
 838         rcu_read_unlock();
 839         return ret;
 840 }
 841 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr);
 842
 843 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 844    implicitly racy: see __nf_conntrack_confirm */
 845 void nf_conntrack_alter_reply(struct nf_conn *ct,
 846                               const struct nf_conntrack_tuple *newreply)
 847 {
 848         struct nf_conn_help *help = nfct_help(ct);
 849
 850         /* Should be unconfirmed, so not in hash table yet */
 851         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 852
 853         pr_debug("Altering reply tuple of %p to ", ct);
 854         nf_ct_dump_tuple(newreply);
 855
 856         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 857         if (ct->master || (help && !hlist_empty(&help->expectations)))
 858                 return;
 859
 860         rcu_read_lock();
 861         __nf_ct_try_assign_helper(ct, GFP_ATOMIC);
 862         rcu_read_unlock();
 863 }
 864 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
 865
 866 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 867 void __nf_ct_refresh_acct(struct nf_conn *ct,
 868                           enum ip_conntrack_info ctinfo,
 869                           const struct sk_buff *skb,
 870                           unsigned long extra_jiffies,
 871                           int do_acct)
 872 {
 873         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 874         NF_CT_ASSERT(skb);
 875
 876         /* Only update if this is not a fixed timeout */
 877         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
 878                 goto acct;
 879
 880         /* If not in hash table, timer will not be active yet */
 881         if (!nf_ct_is_confirmed(ct)) {
 882                 ct->timeout.expires = extra_jiffies;
 883         } else {
 884                 unsigned long newtime = jiffies + extra_jiffies;
 885
 886                 /* Only update the timeout if the new timeout is at least
 887                    HZ jiffies from the old timeout. Need del_timer for race
 888                    avoidance (may already be dying). */
 889                 if (newtime - ct->timeout.expires >= HZ)
 890                         mod_timer_pending(&ct->timeout, newtime);
 891         }
 892
 893 acct:
 894         if (do_acct) {
 895                 struct nf_conn_counter *acct;
 896
 897                 acct = nf_conn_acct_find(ct);
 898                 if (acct) {
 899                         spin_lock_bh(&ct->lock);
 900                         acct[CTINFO2DIR(ctinfo)].packets++;
 901                         acct[CTINFO2DIR(ctinfo)].bytes +=
 902                                 skb->len - skb_network_offset(skb);
 903                         spin_unlock_bh(&ct->lock);
 904                 }
 905         }
 906 }
 907 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 908
 909 bool __nf_ct_kill_acct(struct nf_conn *ct,
 910                        enum ip_conntrack_info ctinfo,
 911                        const struct sk_buff *skb,
 912                        int do_acct)
 913 {
 914         if (do_acct) {
 915                 struct nf_conn_counter *acct;
 916
 917                 acct = nf_conn_acct_find(ct);
 918                 if (acct) {
 919                         spin_lock_bh(&ct->lock);
 920                         acct[CTINFO2DIR(ctinfo)].packets++;
 921                         acct[CTINFO2DIR(ctinfo)].bytes +=
 922                                 skb->len - skb_network_offset(skb);
 923                         spin_unlock_bh(&ct->lock);
 924                 }
 925         }
 926
 927         if (del_timer(&ct->timeout)) {
 928                 ct->timeout.function((unsigned long)ct);
 929                 return true;
 930         }
 931         return false;
 932 }
 933 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct);
 934
 935 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
 936
 937 #include <linux/netfilter/nfnetlink.h>
 938 #include <linux/netfilter/nfnetlink_conntrack.h>
 939 #include <linux/mutex.h>
 940
 941 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 942  * in ip_conntrack_core, since we don't want the protocols to autoload
 943  * or depend on ctnetlink */
 944 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
 945                                const struct nf_conntrack_tuple *tuple)
 946 {
 947         NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port);
 948         NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port);
 949         return 0;
 950
 951 nla_put_failure:
 952         return -1;
 953 }
 954 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
 955
 956 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
 957         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
 958         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
 959 };
 960 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
 961
 962 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
 963                                struct nf_conntrack_tuple *t)
 964 {
 965         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
 966                 return -EINVAL;
 967
 968         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
 969         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
 970
 971         return 0;
 972 }
 973 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
 974
 975 int nf_ct_port_nlattr_tuple_size(void)
 976 {
 977         return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
 978 }
 979 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
 980 #endif
 981
 982 /* Used by ipt_REJECT and ip6t_REJECT. */
 983 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
 984 {
 985         struct nf_conn *ct;
 986         enum ip_conntrack_info ctinfo;
 987
 988         /* This ICMP is in reverse direction to the packet which caused it */
 989         ct = nf_ct_get(skb, &ctinfo);
 990         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
 991                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
 992         else
 993                 ctinfo = IP_CT_RELATED;
 994
 995         /* Attach to new skbuff, and increment count */
 996         nskb->nfct = &ct->ct_general;
 997         nskb->nfctinfo = ctinfo;
 998         nf_conntrack_get(nskb->nfct);
 999 }
1000
1001 /* Bring out ya dead! */
1002 static struct nf_conn *
1003 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data),
1004                 void *data, unsigned int *bucket)
1005 {
1006         struct nf_conntrack_tuple_hash *h;
1007         struct nf_conn *ct;
1008         struct hlist_nulls_node *n;
1009
1010         spin_lock_bh(&nf_conntrack_lock);
1011         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1012                 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) {
1013                         ct = nf_ct_tuplehash_to_ctrack(h);
1014                         if (iter(ct, data))
1015                                 goto found;
1016                 }
1017         }
1018         hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) {
1019                 ct = nf_ct_tuplehash_to_ctrack(h);
1020                 if (iter(ct, data))
1021                         set_bit(IPS_DYING_BIT, &ct->status);
1022         }
1023         spin_unlock_bh(&nf_conntrack_lock);
1024         return NULL;
1025 found:
1026         atomic_inc(&ct->ct_general.use);
1027         spin_unlock_bh(&nf_conntrack_lock);
1028         return ct;
1029 }
1030
1031 void nf_ct_iterate_cleanup(struct net *net,
1032                            int (*iter)(struct nf_conn *i, void *data),
1033                            void *data)
1034 {
1035         struct nf_conn *ct;
1036         unsigned int bucket = 0;
1037
1038         while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) {
1039                 /* Time to push up daises... */
1040                 if (del_timer(&ct->timeout))
1041                         death_by_timeout((unsigned long)ct);
1042                 /* ... else the timer will get him soon. */
1043
1044                 nf_ct_put(ct);
1045         }
1046 }
1047 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup);
1048
1049 struct __nf_ct_flush_report {
1050         u32 pid;
1051         int report;
1052 };
1053
1054 static int kill_report(struct nf_conn *i, void *data)
1055 {
1056         struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
1057
1058         /* If we fail to deliver the event, death_by_timeout() will retry */
1059         if (nf_conntrack_event_report(IPCT_DESTROY, i,
1060                                       fr->pid, fr->report) < 0)
1061                 return 1;
1062
1063         /* Avoid the delivery of the destroy event in death_by_timeout(). */
1064         set_bit(IPS_DYING_BIT, &i->status);
1065         return 1;
1066 }
1067
1068 static int kill_all(struct nf_conn *i, void *data)
1069 {
1070         return 1;
1071 }
1072
1073 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size)
1074 {
1075         if (vmalloced)
1076                 vfree(hash);
1077         else
1078                 free_pages((unsigned long)hash,
1079                            get_order(sizeof(struct hlist_head) * size));
1080 }
1081 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable);
1082
1083 void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
1084 {
1085         struct __nf_ct_flush_report fr = {
1086                 .pid    = pid,
1087                 .report = report,
1088         };
1089         nf_ct_iterate_cleanup(net, kill_report, &fr);
1090 }
1091 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
1092
1093 static void nf_ct_release_dying_list(struct net *net)
1094 {
1095         struct nf_conntrack_tuple_hash *h;
1096         struct nf_conn *ct;
1097         struct hlist_nulls_node *n;
1098
1099         spin_lock_bh(&nf_conntrack_lock);
1100         hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) {
1101                 ct = nf_ct_tuplehash_to_ctrack(h);
1102                 /* never fails to remove them, no listeners at this point */
1103                 nf_ct_kill(ct);
1104         }
1105         spin_unlock_bh(&nf_conntrack_lock);
1106 }
1107
1108 static void nf_conntrack_cleanup_init_net(void)
1109 {
1110         nf_conntrack_helper_fini();
1111         nf_conntrack_proto_fini();
1112         kmem_cache_destroy(nf_conntrack_cachep);
1113 }
1114
1115 static void nf_conntrack_cleanup_net(struct net *net)
1116 {
1117  i_see_dead_people:
1118         nf_ct_iterate_cleanup(net, kill_all, NULL);
1119         nf_ct_release_dying_list(net);
1120         if (atomic_read(&net->ct.count) != 0) {
1121                 schedule();
1122                 goto i_see_dead_people;
1123         }
1124         /* wait until all references to nf_conntrack_untracked are dropped */
1125         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1126                 schedule();
1127
1128         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1129                              nf_conntrack_htable_size);
1130         nf_conntrack_ecache_fini(net);
1131         nf_conntrack_acct_fini(net);
1132         nf_conntrack_expect_fini(net);
1133         free_percpu(net->ct.stat);
1134 }
1135
1136 /* Mishearing the voices in his head, our hero wonders how he's
1137    supposed to kill the mall. */
1138 void nf_conntrack_cleanup(struct net *net)
1139 {
1140         if (net_eq(net, &init_net))
1141                 rcu_assign_pointer(ip_ct_attach, NULL);
1142
1143         /* This makes sure all current packets have passed through
1144            netfilter framework.  Roll on, two-stage module
1145            delete... */
1146         synchronize_net();
1147
1148         nf_conntrack_cleanup_net(net);
1149
1150         if (net_eq(net, &init_net)) {
1151                 rcu_assign_pointer(nf_ct_destroy, NULL);
1152                 nf_conntrack_cleanup_init_net();
1153         }
1154 }
1155
1156 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls)
1157 {
1158         struct hlist_nulls_head *hash;
1159         unsigned int nr_slots, i;
1160         size_t sz;
1161
1162         *vmalloced = 0;
1163
1164         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
1165         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
1166         sz = nr_slots * sizeof(struct hlist_nulls_head);
1167         hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO,
1168                                         get_order(sz));
1169         if (!hash) {
1170                 *vmalloced = 1;
1171                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1172                 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
1173         }
1174
1175         if (hash && nulls)
1176                 for (i = 0; i < nr_slots; i++)
1177                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
1178
1179         return hash;
1180 }
1181 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
1182
1183 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp)
1184 {
1185         int i, bucket, vmalloced, old_vmalloced;
1186         unsigned int hashsize, old_size;
1187         int rnd;
1188         struct hlist_nulls_head *hash, *old_hash;
1189         struct nf_conntrack_tuple_hash *h;
1190
1191         /* On boot, we can set this without any fancy locking. */
1192         if (!nf_conntrack_htable_size)
1193                 return param_set_uint(val, kp);
1194
1195         hashsize = simple_strtoul(val, NULL, 0);
1196         if (!hashsize)
1197                 return -EINVAL;
1198
1199         hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1);
1200         if (!hash)
1201                 return -ENOMEM;
1202
1203         /* We have to rehahs for the new table anyway, so we also can
1204          * use a newrandom seed */
1205         get_random_bytes(&rnd, sizeof(rnd));
1206
1207         /* Lookups in the old hash might happen in parallel, which means we
1208          * might get false negatives during connection lookup. New connections
1209          * created because of a false negative won't make it into the hash
1210          * though since that required taking the lock.
1211          */
1212         spin_lock_bh(&nf_conntrack_lock);
1213         for (i = 0; i < nf_conntrack_htable_size; i++) {
1214                 while (!hlist_nulls_empty(&init_net.ct.hash[i])) {
1215                         h = hlist_nulls_entry(init_net.ct.hash[i].first,
1216                                         struct nf_conntrack_tuple_hash, hnnode);
1217                         hlist_nulls_del_rcu(&h->hnnode);
1218                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1219                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
1220                 }
1221         }
1222         old_size = nf_conntrack_htable_size;
1223         old_vmalloced = init_net.ct.hash_vmalloc;
1224         old_hash = init_net.ct.hash;
1225
1226         nf_conntrack_htable_size = hashsize;
1227         init_net.ct.hash_vmalloc = vmalloced;
1228         init_net.ct.hash = hash;
1229         nf_conntrack_hash_rnd = rnd;
1230         spin_unlock_bh(&nf_conntrack_lock);
1231
1232         nf_ct_free_hashtable(old_hash, old_vmalloced, old_size);
1233         return 0;
1234 }
1235 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
1236
1237 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
1238                   &nf_conntrack_htable_size, 0600);
1239
1240 static int nf_conntrack_init_init_net(void)
1241 {
1242         int max_factor = 8;
1243         int ret;
1244
1245         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1246          * machine has 512 buckets. >= 1GB machines have 16384 buckets. */
1247         if (!nf_conntrack_htable_size) {
1248                 nf_conntrack_htable_size
1249                         = (((totalram_pages << PAGE_SHIFT) / 16384)
1250                            / sizeof(struct hlist_head));
1251                 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
1252                         nf_conntrack_htable_size = 16384;
1253                 if (nf_conntrack_htable_size < 32)
1254                         nf_conntrack_htable_size = 32;
1255
1256                 /* Use a max. factor of four by default to get the same max as
1257                  * with the old struct list_heads. When a table size is given
1258                  * we use the old value of 8 to avoid reducing the max.
1259                  * entries. */
1260                 max_factor = 4;
1261         }
1262         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
1263
1264         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1265                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1266                nf_conntrack_max);
1267
1268         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
1269                                                 sizeof(struct nf_conn),
1270                                                 0, SLAB_DESTROY_BY_RCU, NULL);
1271         if (!nf_conntrack_cachep) {
1272                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1273                 ret = -ENOMEM;
1274                 goto err_cache;
1275         }
1276
1277         ret = nf_conntrack_proto_init();
1278         if (ret < 0)
1279                 goto err_proto;
1280
1281         ret = nf_conntrack_helper_init();
1282         if (ret < 0)
1283                 goto err_helper;
1284
1285         return 0;
1286
1287 err_helper:
1288         nf_conntrack_proto_fini();
1289 err_proto:
1290         kmem_cache_destroy(nf_conntrack_cachep);
1291 err_cache:
1292         return ret;
1293 }
1294
1295 /*
1296  * We need to use special "null" values, not used in hash table
1297  */
1298 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
1299 #define DYING_NULLS_VAL         ((1<<30)+1)
1300
1301 static int nf_conntrack_init_net(struct net *net)
1302 {
1303         int ret;
1304
1305         atomic_set(&net->ct.count, 0);
1306         INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
1307         INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
1308         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
1309         if (!net->ct.stat) {
1310                 ret = -ENOMEM;
1311                 goto err_stat;
1312         }
1313         net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
1314                                              &net->ct.hash_vmalloc, 1);
1315         if (!net->ct.hash) {
1316                 ret = -ENOMEM;
1317                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1318                 goto err_hash;
1319         }
1320         ret = nf_conntrack_expect_init(net);
1321         if (ret < 0)
1322                 goto err_expect;
1323         ret = nf_conntrack_acct_init(net);
1324         if (ret < 0)
1325                 goto err_acct;
1326         ret = nf_conntrack_ecache_init(net);
1327         if (ret < 0)
1328                 goto err_ecache;
1329
1330         /* Set up fake conntrack:
1331             - to never be deleted, not in any hashes */
1332 #ifdef CONFIG_NET_NS
1333         nf_conntrack_untracked.ct_net = &init_net;
1334 #endif
1335         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1336         /*  - and look it like as a confirmed connection */
1337         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1338
1339         return 0;
1340
1341 err_ecache:
1342         nf_conntrack_acct_fini(net);
1343 err_acct:
1344         nf_conntrack_expect_fini(net);
1345 err_expect:
1346         nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
1347                              nf_conntrack_htable_size);
1348 err_hash:
1349         free_percpu(net->ct.stat);
1350 err_stat:
1351         return ret;
1352 }
1353
1354 int nf_conntrack_init(struct net *net)
1355 {
1356         int ret;
1357
1358         if (net_eq(net, &init_net)) {
1359                 ret = nf_conntrack_init_init_net();
1360                 if (ret < 0)
1361                         goto out_init_net;
1362         }
1363         ret = nf_conntrack_init_net(net);
1364         if (ret < 0)
1365                 goto out_net;
1366
1367         if (net_eq(net, &init_net)) {
1368                 /* For use by REJECT target */
1369                 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach);
1370                 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
1371         }
1372         return 0;
1373
1374 out_net:
1375         if (net_eq(net, &init_net))
1376                 nf_conntrack_cleanup_init_net();
1377 out_init_net:
1378         return ret;
1379 }