net/netfilter/nf_conntrack_expect.c

   1 /* Expectation handling for nf_conntrack. */
   2
   3 /* (C) 1999-2001 Paul `Rusty' Russell
   4  * (C) 2002-2006 Netfilter Core Team <[email protected]>
   5  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   6  * (c) 2005-2012 Patrick McHardy <[email protected]>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/netfilter.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/stddef.h>
  19 #include <linux/slab.h>
  20 #include <linux/err.h>
  21 #include <linux/percpu.h>
  22 #include <linux/kernel.h>
  23 #include <linux/jhash.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/export.h>
  26 #include <net/net_namespace.h>
  27
  28 #include <net/netfilter/nf_conntrack.h>
  29 #include <net/netfilter/nf_conntrack_core.h>
  30 #include <net/netfilter/nf_conntrack_expect.h>
  31 #include <net/netfilter/nf_conntrack_helper.h>
  32 #include <net/netfilter/nf_conntrack_tuple.h>
  33 #include <net/netfilter/nf_conntrack_zones.h>
  34
  35 unsigned int nf_ct_expect_hsize __read_mostly;
  36 EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);
  37
  38 unsigned int nf_ct_expect_max __read_mostly;
  39
  40 static struct kmem_cache *nf_ct_expect_cachep __read_mostly;
  41
  42 /* nf_conntrack_expect helper functions */
  43 void nf_ct_unlink_expect_report(struct nf_conntrack_expect *exp,
  44                                 u32 portid, int report)
  45 {
  46         struct nf_conn_help *master_help = nfct_help(exp->master);
  47         struct net *net = nf_ct_exp_net(exp);
  48
  49         NF_CT_ASSERT(master_help);
  50         NF_CT_ASSERT(!timer_pending(&exp->timeout));
  51
  52         hlist_del_rcu(&exp->hnode);
  53         net->ct.expect_count--;
  54
  55         hlist_del(&exp->lnode);
  56         master_help->expecting[exp->class]--;
  57
  58         nf_ct_expect_event_report(IPEXP_DESTROY, exp, portid, report);
  59         nf_ct_expect_put(exp);
  60
  61         NF_CT_STAT_INC(net, expect_delete);
  62 }
  63 EXPORT_SYMBOL_GPL(nf_ct_unlink_expect_report);
  64
  65 static void nf_ct_expectation_timed_out(unsigned long ul_expect)
  66 {
  67         struct nf_conntrack_expect *exp = (void *)ul_expect;
  68
  69         spin_lock_bh(&nf_conntrack_lock);
  70         nf_ct_unlink_expect(exp);
  71         spin_unlock_bh(&nf_conntrack_lock);
  72         nf_ct_expect_put(exp);
  73 }
  74
  75 static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple)
  76 {
  77         unsigned int hash;
  78
  79         if (unlikely(!nf_conntrack_hash_rnd)) {
  80                 init_nf_conntrack_hash_rnd();
  81         }
  82
  83         hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
  84                       (((tuple->dst.protonum ^ tuple->src.l3num) << 16) |
  85                        (__force __u16)tuple->dst.u.all) ^ nf_conntrack_hash_rnd);
  86         return ((u64)hash * nf_ct_expect_hsize) >> 32;
  87 }
  88
  89 struct nf_conntrack_expect *
  90 __nf_ct_expect_find(struct net *net, u16 zone,
  91                     const struct nf_conntrack_tuple *tuple)
  92 {
  93         struct nf_conntrack_expect *i;
  94         unsigned int h;
  95
  96         if (!net->ct.expect_count)
  97                 return NULL;
  98
  99         h = nf_ct_expect_dst_hash(tuple);
 100         hlist_for_each_entry_rcu(i, &net->ct.expect_hash[h], hnode) {
 101                 if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) &&
 102                     nf_ct_zone(i->master) == zone)
 103                         return i;
 104         }
 105         return NULL;
 106 }
 107 EXPORT_SYMBOL_GPL(__nf_ct_expect_find);
 108
 109 /* Just find a expectation corresponding to a tuple. */
 110 struct nf_conntrack_expect *
 111 nf_ct_expect_find_get(struct net *net, u16 zone,
 112                       const struct nf_conntrack_tuple *tuple)
 113 {
 114         struct nf_conntrack_expect *i;
 115
 116         rcu_read_lock();
 117         i = __nf_ct_expect_find(net, zone, tuple);
 118         if (i && !atomic_inc_not_zero(&i->use))
 119                 i = NULL;
 120         rcu_read_unlock();
 121
 122         return i;
 123 }
 124 EXPORT_SYMBOL_GPL(nf_ct_expect_find_get);
 125
 126 /* If an expectation for this connection is found, it gets delete from
 127  * global list then returned. */
 128 struct nf_conntrack_expect *
 129 nf_ct_find_expectation(struct net *net, u16 zone,
 130                        const struct nf_conntrack_tuple *tuple)
 131 {
 132         struct nf_conntrack_expect *i, *exp = NULL;
 133         unsigned int h;
 134
 135         if (!net->ct.expect_count)
 136                 return NULL;
 137
 138         h = nf_ct_expect_dst_hash(tuple);
 139         hlist_for_each_entry(i, &net->ct.expect_hash[h], hnode) {
 140                 if (!(i->flags & NF_CT_EXPECT_INACTIVE) &&
 141                     nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) &&
 142                     nf_ct_zone(i->master) == zone) {
 143                         exp = i;
 144                         break;
 145                 }
 146         }
 147         if (!exp)
 148                 return NULL;
 149
 150         /* If master is not in hash table yet (ie. packet hasn't left
 151            this machine yet), how can other end know about expected?
 152            Hence these are not the droids you are looking for (if
 153            master ct never got confirmed, we'd hold a reference to it
 154            and weird things would happen to future packets). */
 155         if (!nf_ct_is_confirmed(exp->master))
 156                 return NULL;
 157
 158         if (exp->flags & NF_CT_EXPECT_PERMANENT) {
 159                 atomic_inc(&exp->use);
 160                 return exp;
 161         } else if (del_timer(&exp->timeout)) {
 162                 nf_ct_unlink_expect(exp);
 163                 return exp;
 164         }
 165
 166         return NULL;
 167 }
 168
 169 /* delete all expectations for this conntrack */
 170 void nf_ct_remove_expectations(struct nf_conn *ct)
 171 {
 172         struct nf_conn_help *help = nfct_help(ct);
 173         struct nf_conntrack_expect *exp;
 174         struct hlist_node *next;
 175
 176         /* Optimization: most connection never expect any others. */
 177         if (!help)
 178                 return;
 179
 180         hlist_for_each_entry_safe(exp, next, &help->expectations, lnode) {
 181                 if (del_timer(&exp->timeout)) {
 182                         nf_ct_unlink_expect(exp);
 183                         nf_ct_expect_put(exp);
 184                 }
 185         }
 186 }
 187 EXPORT_SYMBOL_GPL(nf_ct_remove_expectations);
 188
 189 /* Would two expected things clash? */
 190 static inline int expect_clash(const struct nf_conntrack_expect *a,
 191                                const struct nf_conntrack_expect *b)
 192 {
 193         /* Part covered by intersection of masks must be unequal,
 194            otherwise they clash */
 195         struct nf_conntrack_tuple_mask intersect_mask;
 196         int count;
 197
 198         intersect_mask.src.u.all = a->mask.src.u.all & b->mask.src.u.all;
 199
 200         for (count = 0; count < NF_CT_TUPLE_L3SIZE; count++){
 201                 intersect_mask.src.u3.all[count] =
 202                         a->mask.src.u3.all[count] & b->mask.src.u3.all[count];
 203         }
 204
 205         return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask);
 206 }
 207
 208 static inline int expect_matches(const struct nf_conntrack_expect *a,
 209                                  const struct nf_conntrack_expect *b)
 210 {
 211         return a->master == b->master && a->class == b->class &&
 212                 nf_ct_tuple_equal(&a->tuple, &b->tuple) &&
 213                 nf_ct_tuple_mask_equal(&a->mask, &b->mask) &&
 214                 nf_ct_zone(a->master) == nf_ct_zone(b->master);
 215 }
 216
 217 /* Generally a bad idea to call this: could have matched already. */
 218 void nf_ct_unexpect_related(struct nf_conntrack_expect *exp)
 219 {
 220         spin_lock_bh(&nf_conntrack_lock);
 221         if (del_timer(&exp->timeout)) {
 222                 nf_ct_unlink_expect(exp);
 223                 nf_ct_expect_put(exp);
 224         }
 225         spin_unlock_bh(&nf_conntrack_lock);
 226 }
 227 EXPORT_SYMBOL_GPL(nf_ct_unexpect_related);
 228
 229 /* We don't increase the master conntrack refcount for non-fulfilled
 230  * conntracks. During the conntrack destruction, the expectations are
 231  * always killed before the conntrack itself */
 232 struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me)
 233 {
 234         struct nf_conntrack_expect *new;
 235
 236         new = kmem_cache_alloc(nf_ct_expect_cachep, GFP_ATOMIC);
 237         if (!new)
 238                 return NULL;
 239
 240         new->master = me;
 241         atomic_set(&new->use, 1);
 242         return new;
 243 }
 244 EXPORT_SYMBOL_GPL(nf_ct_expect_alloc);
 245
 246 void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class,
 247                        u_int8_t family,
 248                        const union nf_inet_addr *saddr,
 249                        const union nf_inet_addr *daddr,
 250                        u_int8_t proto, const __be16 *src, const __be16 *dst)
 251 {
 252         int len;
 253
 254         if (family == AF_INET)
 255                 len = 4;
 256         else
 257                 len = 16;
 258
 259         exp->flags = 0;
 260         exp->class = class;
 261         exp->expectfn = NULL;
 262         exp->helper = NULL;
 263         exp->tuple.src.l3num = family;
 264         exp->tuple.dst.protonum = proto;
 265
 266         if (saddr) {
 267                 memcpy(&exp->tuple.src.u3, saddr, len);
 268                 if (sizeof(exp->tuple.src.u3) > len)
 269                         /* address needs to be cleared for nf_ct_tuple_equal */
 270                         memset((void *)&exp->tuple.src.u3 + len, 0x00,
 271                                sizeof(exp->tuple.src.u3) - len);
 272                 memset(&exp->mask.src.u3, 0xFF, len);
 273                 if (sizeof(exp->mask.src.u3) > len)
 274                         memset((void *)&exp->mask.src.u3 + len, 0x00,
 275                                sizeof(exp->mask.src.u3) - len);
 276         } else {
 277                 memset(&exp->tuple.src.u3, 0x00, sizeof(exp->tuple.src.u3));
 278                 memset(&exp->mask.src.u3, 0x00, sizeof(exp->mask.src.u3));
 279         }
 280
 281         if (src) {
 282                 exp->tuple.src.u.all = *src;
 283                 exp->mask.src.u.all = htons(0xFFFF);
 284         } else {
 285                 exp->tuple.src.u.all = 0;
 286                 exp->mask.src.u.all = 0;
 287         }
 288
 289         memcpy(&exp->tuple.dst.u3, daddr, len);
 290         if (sizeof(exp->tuple.dst.u3) > len)
 291                 /* address needs to be cleared for nf_ct_tuple_equal */
 292                 memset((void *)&exp->tuple.dst.u3 + len, 0x00,
 293                        sizeof(exp->tuple.dst.u3) - len);
 294
 295         exp->tuple.dst.u.all = *dst;
 296
 297 #ifdef CONFIG_NF_NAT_NEEDED
 298         memset(&exp->saved_addr, 0, sizeof(exp->saved_addr));
 299         memset(&exp->saved_proto, 0, sizeof(exp->saved_proto));
 300 #endif
 301 }
 302 EXPORT_SYMBOL_GPL(nf_ct_expect_init);
 303
 304 static void nf_ct_expect_free_rcu(struct rcu_head *head)
 305 {
 306         struct nf_conntrack_expect *exp;
 307
 308         exp = container_of(head, struct nf_conntrack_expect, rcu);
 309         kmem_cache_free(nf_ct_expect_cachep, exp);
 310 }
 311
 312 void nf_ct_expect_put(struct nf_conntrack_expect *exp)
 313 {
 314         if (atomic_dec_and_test(&exp->use))
 315                 call_rcu(&exp->rcu, nf_ct_expect_free_rcu);
 316 }
 317 EXPORT_SYMBOL_GPL(nf_ct_expect_put);
 318
 319 static int nf_ct_expect_insert(struct nf_conntrack_expect *exp)
 320 {
 321         struct nf_conn_help *master_help = nfct_help(exp->master);
 322         struct nf_conntrack_helper *helper;
 323         struct net *net = nf_ct_exp_net(exp);
 324         unsigned int h = nf_ct_expect_dst_hash(&exp->tuple);
 325
 326         /* two references : one for hash insert, one for the timer */
 327         atomic_add(2, &exp->use);
 328
 329         hlist_add_head(&exp->lnode, &master_help->expectations);
 330         master_help->expecting[exp->class]++;
 331
 332         hlist_add_head_rcu(&exp->hnode, &net->ct.expect_hash[h]);
 333         net->ct.expect_count++;
 334
 335         setup_timer(&exp->timeout, nf_ct_expectation_timed_out,
 336                     (unsigned long)exp);
 337         helper = rcu_dereference_protected(master_help->helper,
 338                                            lockdep_is_held(&nf_conntrack_lock));
 339         if (helper) {
 340                 exp->timeout.expires = jiffies +
 341                         helper->expect_policy[exp->class].timeout * HZ;
 342         }
 343         add_timer(&exp->timeout);
 344
 345         NF_CT_STAT_INC(net, expect_create);
 346         return 0;
 347 }
 348
 349 /* Race with expectations being used means we could have none to find; OK. */
 350 static void evict_oldest_expect(struct nf_conn *master,
 351                                 struct nf_conntrack_expect *new)
 352 {
 353         struct nf_conn_help *master_help = nfct_help(master);
 354         struct nf_conntrack_expect *exp, *last = NULL;
 355
 356         hlist_for_each_entry(exp, &master_help->expectations, lnode) {
 357                 if (exp->class == new->class)
 358                         last = exp;
 359         }
 360
 361         if (last && del_timer(&last->timeout)) {
 362                 nf_ct_unlink_expect(last);
 363                 nf_ct_expect_put(last);
 364         }
 365 }
 366
 367 static inline int __nf_ct_expect_check(struct nf_conntrack_expect *expect)
 368 {
 369         const struct nf_conntrack_expect_policy *p;
 370         struct nf_conntrack_expect *i;
 371         struct nf_conn *master = expect->master;
 372         struct nf_conn_help *master_help = nfct_help(master);
 373         struct nf_conntrack_helper *helper;
 374         struct net *net = nf_ct_exp_net(expect);
 375         struct hlist_node *next;
 376         unsigned int h;
 377         int ret = 1;
 378
 379         if (!master_help) {
 380                 ret = -ESHUTDOWN;
 381                 goto out;
 382         }
 383         h = nf_ct_expect_dst_hash(&expect->tuple);
 384         hlist_for_each_entry_safe(i, next, &net->ct.expect_hash[h], hnode) {
 385                 if (expect_matches(i, expect)) {
 386                         if (del_timer(&i->timeout)) {
 387                                 nf_ct_unlink_expect(i);
 388                                 nf_ct_expect_put(i);
 389                                 break;
 390                         }
 391                 } else if (expect_clash(i, expect)) {
 392                         ret = -EBUSY;
 393                         goto out;
 394                 }
 395         }
 396         /* Will be over limit? */
 397         helper = rcu_dereference_protected(master_help->helper,
 398                                            lockdep_is_held(&nf_conntrack_lock));
 399         if (helper) {
 400                 p = &helper->expect_policy[expect->class];
 401                 if (p->max_expected &&
 402                     master_help->expecting[expect->class] >= p->max_expected) {
 403                         evict_oldest_expect(master, expect);
 404                         if (master_help->expecting[expect->class]
 405                                                 >= p->max_expected) {
 406                                 ret = -EMFILE;
 407                                 goto out;
 408                         }
 409                 }
 410         }
 411
 412         if (net->ct.expect_count >= nf_ct_expect_max) {
 413                 net_warn_ratelimited("nf_conntrack: expectation table full\n");
 414                 ret = -EMFILE;
 415         }
 416 out:
 417         return ret;
 418 }
 419
 420 int nf_ct_expect_related_report(struct nf_conntrack_expect *expect,
 421                                 u32 portid, int report)
 422 {
 423         int ret;
 424
 425         spin_lock_bh(&nf_conntrack_lock);
 426         ret = __nf_ct_expect_check(expect);
 427         if (ret <= 0)
 428                 goto out;
 429
 430         ret = nf_ct_expect_insert(expect);
 431         if (ret < 0)
 432                 goto out;
 433         spin_unlock_bh(&nf_conntrack_lock);
 434         nf_ct_expect_event_report(IPEXP_NEW, expect, portid, report);
 435         return ret;
 436 out:
 437         spin_unlock_bh(&nf_conntrack_lock);
 438         return ret;
 439 }
 440 EXPORT_SYMBOL_GPL(nf_ct_expect_related_report);
 441
 442 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 443 struct ct_expect_iter_state {
 444         struct seq_net_private p;
 445         unsigned int bucket;
 446 };
 447
 448 static struct hlist_node *ct_expect_get_first(struct seq_file *seq)
 449 {
 450         struct net *net = seq_file_net(seq);
 451         struct ct_expect_iter_state *st = seq->private;
 452         struct hlist_node *n;
 453
 454         for (st->bucket = 0; st->bucket < nf_ct_expect_hsize; st->bucket++) {
 455                 n = rcu_dereference(hlist_first_rcu(&net->ct.expect_hash[st->bucket]));
 456                 if (n)
 457                         return n;
 458         }
 459         return NULL;
 460 }
 461
 462 static struct hlist_node *ct_expect_get_next(struct seq_file *seq,
 463                                              struct hlist_node *head)
 464 {
 465         struct net *net = seq_file_net(seq);
 466         struct ct_expect_iter_state *st = seq->private;
 467
 468         head = rcu_dereference(hlist_next_rcu(head));
 469         while (head == NULL) {
 470                 if (++st->bucket >= nf_ct_expect_hsize)
 471                         return NULL;
 472                 head = rcu_dereference(hlist_first_rcu(&net->ct.expect_hash[st->bucket]));
 473         }
 474         return head;
 475 }
 476
 477 static struct hlist_node *ct_expect_get_idx(struct seq_file *seq, loff_t pos)
 478 {
 479         struct hlist_node *head = ct_expect_get_first(seq);
 480
 481         if (head)
 482                 while (pos && (head = ct_expect_get_next(seq, head)))
 483                         pos--;
 484         return pos ? NULL : head;
 485 }
 486
 487 static void *exp_seq_start(struct seq_file *seq, loff_t *pos)
 488         __acquires(RCU)
 489 {
 490         rcu_read_lock();
 491         return ct_expect_get_idx(seq, *pos);
 492 }
 493
 494 static void *exp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 495 {
 496         (*pos)++;
 497         return ct_expect_get_next(seq, v);
 498 }
 499
 500 static void exp_seq_stop(struct seq_file *seq, void *v)
 501         __releases(RCU)
 502 {
 503         rcu_read_unlock();
 504 }
 505
 506 static int exp_seq_show(struct seq_file *s, void *v)
 507 {
 508         struct nf_conntrack_expect *expect;
 509         struct nf_conntrack_helper *helper;
 510         struct hlist_node *n = v;
 511         char *delim = "";
 512
 513         expect = hlist_entry(n, struct nf_conntrack_expect, hnode);
 514
 515         if (expect->timeout.function)
 516                 seq_printf(s, "%ld ", timer_pending(&expect->timeout)
 517                            ? (long)(expect->timeout.expires - jiffies)/HZ : 0);
 518         else
 519                 seq_printf(s, "- ");
 520         seq_printf(s, "l3proto = %u proto=%u ",
 521                    expect->tuple.src.l3num,
 522                    expect->tuple.dst.protonum);
 523         print_tuple(s, &expect->tuple,
 524                     __nf_ct_l3proto_find(expect->tuple.src.l3num),
 525                     __nf_ct_l4proto_find(expect->tuple.src.l3num,
 526                                        expect->tuple.dst.protonum));
 527
 528         if (expect->flags & NF_CT_EXPECT_PERMANENT) {
 529                 seq_printf(s, "PERMANENT");
 530                 delim = ",";
 531         }
 532         if (expect->flags & NF_CT_EXPECT_INACTIVE) {
 533                 seq_printf(s, "%sINACTIVE", delim);
 534                 delim = ",";
 535         }
 536         if (expect->flags & NF_CT_EXPECT_USERSPACE)
 537                 seq_printf(s, "%sUSERSPACE", delim);
 538
 539         helper = rcu_dereference(nfct_help(expect->master)->helper);
 540         if (helper) {
 541                 seq_printf(s, "%s%s", expect->flags ? " " : "", helper->name);
 542                 if (helper->expect_policy[expect->class].name)
 543                         seq_printf(s, "/%s",
 544                                    helper->expect_policy[expect->class].name);
 545         }
 546
 547         return seq_putc(s, '\n');
 548 }
 549
 550 static const struct seq_operations exp_seq_ops = {
 551         .start = exp_seq_start,
 552         .next = exp_seq_next,
 553         .stop = exp_seq_stop,
 554         .show = exp_seq_show
 555 };
 556
 557 static int exp_open(struct inode *inode, struct file *file)
 558 {
 559         return seq_open_net(inode, file, &exp_seq_ops,
 560                         sizeof(struct ct_expect_iter_state));
 561 }
 562
 563 static const struct file_operations exp_file_ops = {
 564         .owner   = THIS_MODULE,
 565         .open    = exp_open,
 566         .read    = seq_read,
 567         .llseek  = seq_lseek,
 568         .release = seq_release_net,
 569 };
 570 #endif /* CONFIG_NF_CONNTRACK_PROCFS */
 571
 572 static int exp_proc_init(struct net *net)
 573 {
 574 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 575         struct proc_dir_entry *proc;
 576
 577         proc = proc_create("nf_conntrack_expect", 0440, net->proc_net,
 578                            &exp_file_ops);
 579         if (!proc)
 580                 return -ENOMEM;
 581 #endif /* CONFIG_NF_CONNTRACK_PROCFS */
 582         return 0;
 583 }
 584
 585 static void exp_proc_remove(struct net *net)
 586 {
 587 #ifdef CONFIG_NF_CONNTRACK_PROCFS
 588         remove_proc_entry("nf_conntrack_expect", net->proc_net);
 589 #endif /* CONFIG_NF_CONNTRACK_PROCFS */
 590 }
 591
 592 module_param_named(expect_hashsize, nf_ct_expect_hsize, uint, 0400);
 593
 594 int nf_conntrack_expect_pernet_init(struct net *net)
 595 {
 596         int err = -ENOMEM;
 597
 598         net->ct.expect_count = 0;
 599         net->ct.expect_hash = nf_ct_alloc_hashtable(&nf_ct_expect_hsize, 0);
 600         if (net->ct.expect_hash == NULL)
 601                 goto err1;
 602
 603         err = exp_proc_init(net);
 604         if (err < 0)
 605                 goto err2;
 606
 607         return 0;
 608 err2:
 609         nf_ct_free_hashtable(net->ct.expect_hash, nf_ct_expect_hsize);
 610 err1:
 611         return err;
 612 }
 613
 614 void nf_conntrack_expect_pernet_fini(struct net *net)
 615 {
 616         exp_proc_remove(net);
 617         nf_ct_free_hashtable(net->ct.expect_hash, nf_ct_expect_hsize);
 618 }
 619
 620 int nf_conntrack_expect_init(void)
 621 {
 622         if (!nf_ct_expect_hsize) {
 623                 nf_ct_expect_hsize = nf_conntrack_htable_size / 256;
 624                 if (!nf_ct_expect_hsize)
 625                         nf_ct_expect_hsize = 1;
 626         }
 627         nf_ct_expect_max = nf_ct_expect_hsize * 4;
 628         nf_ct_expect_cachep = kmem_cache_create("nf_conntrack_expect",
 629                                 sizeof(struct nf_conntrack_expect),
 630                                 0, 0, NULL);
 631         if (!nf_ct_expect_cachep)
 632                 return -ENOMEM;
 633         return 0;
 634 }
 635
 636 void nf_conntrack_expect_fini(void)
 637 {
 638         rcu_barrier(); /* Wait for call_rcu() before destroy */
 639         kmem_cache_destroy(nf_ct_expect_cachep);
 640 }