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