net/ipv4/netfilter/ip_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) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   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  * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
  13  *      - new API and handling of conntrack/nat helpers
  14  *      - now capable of multiple expectations for one master
  15  * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
  16  *      - add usage/reference counts to ip_conntrack_expect
  17  *      - export ip_conntrack[_expect]_{find_get,put} functions
  18  * */
  19
  20 #include <linux/config.h>
  21 #include <linux/types.h>
  22 #include <linux/icmp.h>
  23 #include <linux/ip.h>
  24 #include <linux/netfilter.h>
  25 #include <linux/netfilter_ipv4.h>
  26 #include <linux/module.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/proc_fs.h>
  29 #include <linux/vmalloc.h>
  30 #include <net/checksum.h>
  31 #include <net/ip.h>
  32 #include <linux/stddef.h>
  33 #include <linux/sysctl.h>
  34 #include <linux/slab.h>
  35 #include <linux/random.h>
  36 #include <linux/jhash.h>
  37 #include <linux/err.h>
  38 #include <linux/percpu.h>
  39 #include <linux/moduleparam.h>
  40
  41 /* ip_conntrack_lock protects the main hash table, protocol/helper/expected
  42    registrations, conntrack timers*/
  43 #define ASSERT_READ_LOCK(x)
  44 #define ASSERT_WRITE_LOCK(x)
  45
  46 #include <linux/netfilter_ipv4/ip_conntrack.h>
  47 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
  48 #include <linux/netfilter_ipv4/ip_conntrack_helper.h>
  49 #include <linux/netfilter_ipv4/ip_conntrack_core.h>
  50 #include <linux/netfilter_ipv4/listhelp.h>
  51
  52 #define IP_CONNTRACK_VERSION    "2.1"
  53
  54 #if 0
  55 #define DEBUGP printk
  56 #else
  57 #define DEBUGP(format, args...)
  58 #endif
  59
  60 DEFINE_RWLOCK(ip_conntrack_lock);
  61
  62 /* ip_conntrack_standalone needs this */
  63 atomic_t ip_conntrack_count = ATOMIC_INIT(0);
  64
  65 void (*ip_conntrack_destroyed)(struct ip_conntrack *conntrack) = NULL;
  66 LIST_HEAD(ip_conntrack_expect_list);
  67 struct ip_conntrack_protocol *ip_ct_protos[MAX_IP_CT_PROTO];
  68 static LIST_HEAD(helpers);
  69 unsigned int ip_conntrack_htable_size = 0;
  70 int ip_conntrack_max;
  71 struct list_head *ip_conntrack_hash;
  72 static kmem_cache_t *ip_conntrack_cachep;
  73 static kmem_cache_t *ip_conntrack_expect_cachep;
  74 struct ip_conntrack ip_conntrack_untracked;
  75 unsigned int ip_ct_log_invalid;
  76 static LIST_HEAD(unconfirmed);
  77 static int ip_conntrack_vmalloc;
  78
  79 DEFINE_PER_CPU(struct ip_conntrack_stat, ip_conntrack_stat);
  80
  81 void
  82 ip_conntrack_put(struct ip_conntrack *ct)
  83 {
  84         IP_NF_ASSERT(ct);
  85         nf_conntrack_put(&ct->ct_general);
  86 }
  87
  88 static int ip_conntrack_hash_rnd_initted;
  89 static unsigned int ip_conntrack_hash_rnd;
  90
  91 static u_int32_t
  92 hash_conntrack(const struct ip_conntrack_tuple *tuple)
  93 {
  94 #if 0
  95         dump_tuple(tuple);
  96 #endif
  97         return (jhash_3words(tuple->src.ip,
  98                              (tuple->dst.ip ^ tuple->dst.protonum),
  99                              (tuple->src.u.all | (tuple->dst.u.all << 16)),
 100                              ip_conntrack_hash_rnd) % ip_conntrack_htable_size);
 101 }
 102
 103 int
 104 ip_ct_get_tuple(const struct iphdr *iph,
 105                 const struct sk_buff *skb,
 106                 unsigned int dataoff,
 107                 struct ip_conntrack_tuple *tuple,
 108                 const struct ip_conntrack_protocol *protocol)
 109 {
 110         /* Never happen */
 111         if (iph->frag_off & htons(IP_OFFSET)) {
 112                 printk("ip_conntrack_core: Frag of proto %u.\n",
 113                        iph->protocol);
 114                 return 0;
 115         }
 116
 117         tuple->src.ip = iph->saddr;
 118         tuple->dst.ip = iph->daddr;
 119         tuple->dst.protonum = iph->protocol;
 120         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 121
 122         return protocol->pkt_to_tuple(skb, dataoff, tuple);
 123 }
 124
 125 int
 126 ip_ct_invert_tuple(struct ip_conntrack_tuple *inverse,
 127                    const struct ip_conntrack_tuple *orig,
 128                    const struct ip_conntrack_protocol *protocol)
 129 {
 130         inverse->src.ip = orig->dst.ip;
 131         inverse->dst.ip = orig->src.ip;
 132         inverse->dst.protonum = orig->dst.protonum;
 133         inverse->dst.dir = !orig->dst.dir;
 134
 135         return protocol->invert_tuple(inverse, orig);
 136 }
 137
 138
 139 /* ip_conntrack_expect helper functions */
 140 static void unlink_expect(struct ip_conntrack_expect *exp)
 141 {
 142         ASSERT_WRITE_LOCK(&ip_conntrack_lock);
 143         IP_NF_ASSERT(!timer_pending(&exp->timeout));
 144         list_del(&exp->list);
 145         CONNTRACK_STAT_INC(expect_delete);
 146         exp->master->expecting--;
 147 }
 148
 149 static void expectation_timed_out(unsigned long ul_expect)
 150 {
 151         struct ip_conntrack_expect *exp = (void *)ul_expect;
 152
 153         write_lock_bh(&ip_conntrack_lock);
 154         unlink_expect(exp);
 155         write_unlock_bh(&ip_conntrack_lock);
 156         ip_conntrack_expect_put(exp);
 157 }
 158
 159 /* If an expectation for this connection is found, it gets delete from
 160  * global list then returned. */
 161 static struct ip_conntrack_expect *
 162 find_expectation(const struct ip_conntrack_tuple *tuple)
 163 {
 164         struct ip_conntrack_expect *i;
 165
 166         list_for_each_entry(i, &ip_conntrack_expect_list, list) {
 167                 /* If master is not in hash table yet (ie. packet hasn't left
 168                    this machine yet), how can other end know about expected?
 169                    Hence these are not the droids you are looking for (if
 170                    master ct never got confirmed, we'd hold a reference to it
 171                    and weird things would happen to future packets). */
 172                 if (ip_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask)
 173                     && is_confirmed(i->master)
 174                     && del_timer(&i->timeout)) {
 175                         unlink_expect(i);
 176                         return i;
 177                 }
 178         }
 179         return NULL;
 180 }
 181
 182 /* delete all expectations for this conntrack */
 183 static void remove_expectations(struct ip_conntrack *ct)
 184 {
 185         struct ip_conntrack_expect *i, *tmp;
 186
 187         /* Optimization: most connection never expect any others. */
 188         if (ct->expecting == 0)
 189                 return;
 190
 191         list_for_each_entry_safe(i, tmp, &ip_conntrack_expect_list, list) {
 192                 if (i->master == ct && del_timer(&i->timeout)) {
 193                         unlink_expect(i);
 194                         ip_conntrack_expect_put(i);
 195                 }
 196         }
 197 }
 198
 199 static void
 200 clean_from_lists(struct ip_conntrack *ct)
 201 {
 202         unsigned int ho, hr;
 203
 204         DEBUGP("clean_from_lists(%p)\n", ct);
 205         ASSERT_WRITE_LOCK(&ip_conntrack_lock);
 206
 207         ho = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 208         hr = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 209         LIST_DELETE(&ip_conntrack_hash[ho], &ct->tuplehash[IP_CT_DIR_ORIGINAL]);
 210         LIST_DELETE(&ip_conntrack_hash[hr], &ct->tuplehash[IP_CT_DIR_REPLY]);
 211
 212         /* Destroy all pending expectations */
 213         remove_expectations(ct);
 214 }
 215
 216 static void
 217 destroy_conntrack(struct nf_conntrack *nfct)
 218 {
 219         struct ip_conntrack *ct = (struct ip_conntrack *)nfct;
 220         struct ip_conntrack_protocol *proto;
 221
 222         DEBUGP("destroy_conntrack(%p)\n", ct);
 223         IP_NF_ASSERT(atomic_read(&nfct->use) == 0);
 224         IP_NF_ASSERT(!timer_pending(&ct->timeout));
 225
 226         /* To make sure we don't get any weird locking issues here:
 227          * destroy_conntrack() MUST NOT be called with a write lock
 228          * to ip_conntrack_lock!!! -HW */
 229         proto = ip_ct_find_proto(ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 230         if (proto && proto->destroy)
 231                 proto->destroy(ct);
 232
 233         if (ip_conntrack_destroyed)
 234                 ip_conntrack_destroyed(ct);
 235
 236         write_lock_bh(&ip_conntrack_lock);
 237         /* Expectations will have been removed in clean_from_lists,
 238          * except TFTP can create an expectation on the first packet,
 239          * before connection is in the list, so we need to clean here,
 240          * too. */
 241         remove_expectations(ct);
 242
 243         /* We overload first tuple to link into unconfirmed list. */
 244         if (!is_confirmed(ct)) {
 245                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 246                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 247         }
 248
 249         CONNTRACK_STAT_INC(delete);
 250         write_unlock_bh(&ip_conntrack_lock);
 251
 252         if (ct->master)
 253                 ip_conntrack_put(ct->master);
 254
 255         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 256         kmem_cache_free(ip_conntrack_cachep, ct);
 257         atomic_dec(&ip_conntrack_count);
 258 }
 259
 260 static void death_by_timeout(unsigned long ul_conntrack)
 261 {
 262         struct ip_conntrack *ct = (void *)ul_conntrack;
 263
 264         write_lock_bh(&ip_conntrack_lock);
 265         /* Inside lock so preempt is disabled on module removal path.
 266          * Otherwise we can get spurious warnings. */
 267         CONNTRACK_STAT_INC(delete_list);
 268         clean_from_lists(ct);
 269         write_unlock_bh(&ip_conntrack_lock);
 270         ip_conntrack_put(ct);
 271 }
 272
 273 static inline int
 274 conntrack_tuple_cmp(const struct ip_conntrack_tuple_hash *i,
 275                     const struct ip_conntrack_tuple *tuple,
 276                     const struct ip_conntrack *ignored_conntrack)
 277 {
 278         ASSERT_READ_LOCK(&ip_conntrack_lock);
 279         return tuplehash_to_ctrack(i) != ignored_conntrack
 280                 && ip_ct_tuple_equal(tuple, &i->tuple);
 281 }
 282
 283 static struct ip_conntrack_tuple_hash *
 284 __ip_conntrack_find(const struct ip_conntrack_tuple *tuple,
 285                     const struct ip_conntrack *ignored_conntrack)
 286 {
 287         struct ip_conntrack_tuple_hash *h;
 288         unsigned int hash = hash_conntrack(tuple);
 289
 290         ASSERT_READ_LOCK(&ip_conntrack_lock);
 291         list_for_each_entry(h, &ip_conntrack_hash[hash], list) {
 292                 if (conntrack_tuple_cmp(h, tuple, ignored_conntrack)) {
 293                         CONNTRACK_STAT_INC(found);
 294                         return h;
 295                 }
 296                 CONNTRACK_STAT_INC(searched);
 297         }
 298
 299         return NULL;
 300 }
 301
 302 /* Find a connection corresponding to a tuple. */
 303 struct ip_conntrack_tuple_hash *
 304 ip_conntrack_find_get(const struct ip_conntrack_tuple *tuple,
 305                       const struct ip_conntrack *ignored_conntrack)
 306 {
 307         struct ip_conntrack_tuple_hash *h;
 308
 309         read_lock_bh(&ip_conntrack_lock);
 310         h = __ip_conntrack_find(tuple, ignored_conntrack);
 311         if (h)
 312                 atomic_inc(&tuplehash_to_ctrack(h)->ct_general.use);
 313         read_unlock_bh(&ip_conntrack_lock);
 314
 315         return h;
 316 }
 317
 318 /* Confirm a connection given skb; places it in hash table */
 319 int
 320 __ip_conntrack_confirm(struct sk_buff **pskb)
 321 {
 322         unsigned int hash, repl_hash;
 323         struct ip_conntrack *ct;
 324         enum ip_conntrack_info ctinfo;
 325
 326         ct = ip_conntrack_get(*pskb, &ctinfo);
 327
 328         /* ipt_REJECT uses ip_conntrack_attach to attach related
 329            ICMP/TCP RST packets in other direction.  Actual packet
 330            which created connection will be IP_CT_NEW or for an
 331            expected connection, IP_CT_RELATED. */
 332         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 333                 return NF_ACCEPT;
 334
 335         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 336         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 337
 338         /* We're not in hash table, and we refuse to set up related
 339            connections for unconfirmed conns.  But packet copies and
 340            REJECT will give spurious warnings here. */
 341         /* IP_NF_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 342
 343         /* No external references means noone else could have
 344            confirmed us. */
 345         IP_NF_ASSERT(!is_confirmed(ct));
 346         DEBUGP("Confirming conntrack %p\n", ct);
 347
 348         write_lock_bh(&ip_conntrack_lock);
 349
 350         /* See if there's one in the list already, including reverse:
 351            NAT could have grabbed it without realizing, since we're
 352            not in the hash.  If there is, we lost race. */
 353         if (!LIST_FIND(&ip_conntrack_hash[hash],
 354                        conntrack_tuple_cmp,
 355                        struct ip_conntrack_tuple_hash *,
 356                        &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, NULL)
 357             && !LIST_FIND(&ip_conntrack_hash[repl_hash],
 358                           conntrack_tuple_cmp,
 359                           struct ip_conntrack_tuple_hash *,
 360                           &ct->tuplehash[IP_CT_DIR_REPLY].tuple, NULL)) {
 361                 /* Remove from unconfirmed list */
 362                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 363
 364                 list_prepend(&ip_conntrack_hash[hash],
 365                              &ct->tuplehash[IP_CT_DIR_ORIGINAL]);
 366                 list_prepend(&ip_conntrack_hash[repl_hash],
 367                              &ct->tuplehash[IP_CT_DIR_REPLY]);
 368                 /* Timer relative to confirmation time, not original
 369                    setting time, otherwise we'd get timer wrap in
 370                    weird delay cases. */
 371                 ct->timeout.expires += jiffies;
 372                 add_timer(&ct->timeout);
 373                 atomic_inc(&ct->ct_general.use);
 374                 set_bit(IPS_CONFIRMED_BIT, &ct->status);
 375                 CONNTRACK_STAT_INC(insert);
 376                 write_unlock_bh(&ip_conntrack_lock);
 377                 return NF_ACCEPT;
 378         }
 379
 380         CONNTRACK_STAT_INC(insert_failed);
 381         write_unlock_bh(&ip_conntrack_lock);
 382
 383         return NF_DROP;
 384 }
 385
 386 /* Returns true if a connection correspondings to the tuple (required
 387    for NAT). */
 388 int
 389 ip_conntrack_tuple_taken(const struct ip_conntrack_tuple *tuple,
 390                          const struct ip_conntrack *ignored_conntrack)
 391 {
 392         struct ip_conntrack_tuple_hash *h;
 393
 394         read_lock_bh(&ip_conntrack_lock);
 395         h = __ip_conntrack_find(tuple, ignored_conntrack);
 396         read_unlock_bh(&ip_conntrack_lock);
 397
 398         return h != NULL;
 399 }
 400
 401 /* There's a small race here where we may free a just-assured
 402    connection.  Too bad: we're in trouble anyway. */
 403 static inline int unreplied(const struct ip_conntrack_tuple_hash *i)
 404 {
 405         return !(test_bit(IPS_ASSURED_BIT, &tuplehash_to_ctrack(i)->status));
 406 }
 407
 408 static int early_drop(struct list_head *chain)
 409 {
 410         /* Traverse backwards: gives us oldest, which is roughly LRU */
 411         struct ip_conntrack_tuple_hash *h;
 412         struct ip_conntrack *ct = NULL;
 413         int dropped = 0;
 414
 415         read_lock_bh(&ip_conntrack_lock);
 416         h = LIST_FIND_B(chain, unreplied, struct ip_conntrack_tuple_hash *);
 417         if (h) {
 418                 ct = tuplehash_to_ctrack(h);
 419                 atomic_inc(&ct->ct_general.use);
 420         }
 421         read_unlock_bh(&ip_conntrack_lock);
 422
 423         if (!ct)
 424                 return dropped;
 425
 426         if (del_timer(&ct->timeout)) {
 427                 death_by_timeout((unsigned long)ct);
 428                 dropped = 1;
 429                 CONNTRACK_STAT_INC(early_drop);
 430         }
 431         ip_conntrack_put(ct);
 432         return dropped;
 433 }
 434
 435 static inline int helper_cmp(const struct ip_conntrack_helper *i,
 436                              const struct ip_conntrack_tuple *rtuple)
 437 {
 438         return ip_ct_tuple_mask_cmp(rtuple, &i->tuple, &i->mask);
 439 }
 440
 441 static struct ip_conntrack_helper *ip_ct_find_helper(const struct ip_conntrack_tuple *tuple)
 442 {
 443         return LIST_FIND(&helpers, helper_cmp,
 444                          struct ip_conntrack_helper *,
 445                          tuple);
 446 }
 447
 448 /* Allocate a new conntrack: we return -ENOMEM if classification
 449    failed due to stress.  Otherwise it really is unclassifiable. */
 450 static struct ip_conntrack_tuple_hash *
 451 init_conntrack(const struct ip_conntrack_tuple *tuple,
 452                struct ip_conntrack_protocol *protocol,
 453                struct sk_buff *skb)
 454 {
 455         struct ip_conntrack *conntrack;
 456         struct ip_conntrack_tuple repl_tuple;
 457         size_t hash;
 458         struct ip_conntrack_expect *exp;
 459
 460         if (!ip_conntrack_hash_rnd_initted) {
 461                 get_random_bytes(&ip_conntrack_hash_rnd, 4);
 462                 ip_conntrack_hash_rnd_initted = 1;
 463         }
 464
 465         hash = hash_conntrack(tuple);
 466
 467         if (ip_conntrack_max
 468             && atomic_read(&ip_conntrack_count) >= ip_conntrack_max) {
 469                 /* Try dropping from this hash chain. */
 470                 if (!early_drop(&ip_conntrack_hash[hash])) {
 471                         if (net_ratelimit())
 472                                 printk(KERN_WARNING
 473                                        "ip_conntrack: table full, dropping"
 474                                        " packet.\n");
 475                         return ERR_PTR(-ENOMEM);
 476                 }
 477         }
 478
 479         if (!ip_ct_invert_tuple(&repl_tuple, tuple, protocol)) {
 480                 DEBUGP("Can't invert tuple.\n");
 481                 return NULL;
 482         }
 483
 484         conntrack = kmem_cache_alloc(ip_conntrack_cachep, GFP_ATOMIC);
 485         if (!conntrack) {
 486                 DEBUGP("Can't allocate conntrack.\n");
 487                 return ERR_PTR(-ENOMEM);
 488         }
 489
 490         memset(conntrack, 0, sizeof(*conntrack));
 491         atomic_set(&conntrack->ct_general.use, 1);
 492         conntrack->ct_general.destroy = destroy_conntrack;
 493         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *tuple;
 494         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = repl_tuple;
 495         if (!protocol->new(conntrack, skb)) {
 496                 kmem_cache_free(ip_conntrack_cachep, conntrack);
 497                 return NULL;
 498         }
 499         /* Don't set timer yet: wait for confirmation */
 500         init_timer(&conntrack->timeout);
 501         conntrack->timeout.data = (unsigned long)conntrack;
 502         conntrack->timeout.function = death_by_timeout;
 503
 504         write_lock_bh(&ip_conntrack_lock);
 505         exp = find_expectation(tuple);
 506
 507         if (exp) {
 508                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 509                         conntrack, exp);
 510                 /* Welcome, Mr. Bond.  We've been expecting you... */
 511                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 512                 conntrack->master = exp->master;
 513 #ifdef CONFIG_IP_NF_CONNTRACK_MARK
 514                 conntrack->mark = exp->master->mark;
 515 #endif
 516 #if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
 517     defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
 518                 /* this is ugly, but there is no other place where to put it */
 519                 conntrack->nat.masq_index = exp->master->nat.masq_index;
 520 #endif
 521                 nf_conntrack_get(&conntrack->master->ct_general);
 522                 CONNTRACK_STAT_INC(expect_new);
 523         } else {
 524                 conntrack->helper = ip_ct_find_helper(&repl_tuple);
 525
 526                 CONNTRACK_STAT_INC(new);
 527         }
 528
 529         /* Overload tuple linked list to put us in unconfirmed list. */
 530         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 531
 532         atomic_inc(&ip_conntrack_count);
 533         write_unlock_bh(&ip_conntrack_lock);
 534
 535         if (exp) {
 536                 if (exp->expectfn)
 537                         exp->expectfn(conntrack, exp);
 538                 ip_conntrack_expect_put(exp);
 539         }
 540
 541         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 542 }
 543
 544 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 545 static inline struct ip_conntrack *
 546 resolve_normal_ct(struct sk_buff *skb,
 547                   struct ip_conntrack_protocol *proto,
 548                   int *set_reply,
 549                   unsigned int hooknum,
 550                   enum ip_conntrack_info *ctinfo)
 551 {
 552         struct ip_conntrack_tuple tuple;
 553         struct ip_conntrack_tuple_hash *h;
 554         struct ip_conntrack *ct;
 555
 556         IP_NF_ASSERT((skb->nh.iph->frag_off & htons(IP_OFFSET)) == 0);
 557
 558         if (!ip_ct_get_tuple(skb->nh.iph, skb, skb->nh.iph->ihl*4,
 559                                 &tuple,proto))
 560                 return NULL;
 561
 562         /* look for tuple match */
 563         h = ip_conntrack_find_get(&tuple, NULL);
 564         if (!h) {
 565                 h = init_conntrack(&tuple, proto, skb);
 566                 if (!h)
 567                         return NULL;
 568                 if (IS_ERR(h))
 569                         return (void *)h;
 570         }
 571         ct = tuplehash_to_ctrack(h);
 572
 573         /* It exists; we have (non-exclusive) reference. */
 574         if (DIRECTION(h) == IP_CT_DIR_REPLY) {
 575                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 576                 /* Please set reply bit if this packet OK */
 577                 *set_reply = 1;
 578         } else {
 579                 /* Once we've had two way comms, always ESTABLISHED. */
 580                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 581                         DEBUGP("ip_conntrack_in: normal packet for %p\n",
 582                                ct);
 583                         *ctinfo = IP_CT_ESTABLISHED;
 584                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 585                         DEBUGP("ip_conntrack_in: related packet for %p\n",
 586                                ct);
 587                         *ctinfo = IP_CT_RELATED;
 588                 } else {
 589                         DEBUGP("ip_conntrack_in: new packet for %p\n",
 590                                ct);
 591                         *ctinfo = IP_CT_NEW;
 592                 }
 593                 *set_reply = 0;
 594         }
 595         skb->nfct = &ct->ct_general;
 596         skb->nfctinfo = *ctinfo;
 597         return ct;
 598 }
 599
 600 /* Netfilter hook itself. */
 601 unsigned int ip_conntrack_in(unsigned int hooknum,
 602                              struct sk_buff **pskb,
 603                              const struct net_device *in,
 604                              const struct net_device *out,
 605                              int (*okfn)(struct sk_buff *))
 606 {
 607         struct ip_conntrack *ct;
 608         enum ip_conntrack_info ctinfo;
 609         struct ip_conntrack_protocol *proto;
 610         int set_reply;
 611         int ret;
 612
 613         /* Previously seen (loopback or untracked)?  Ignore. */
 614         if ((*pskb)->nfct) {
 615                 CONNTRACK_STAT_INC(ignore);
 616                 return NF_ACCEPT;
 617         }
 618
 619         /* Never happen */
 620         if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) {
 621                 if (net_ratelimit()) {
 622                 printk(KERN_ERR "ip_conntrack_in: Frag of proto %u (hook=%u)\n",
 623                        (*pskb)->nh.iph->protocol, hooknum);
 624                 }
 625                 return NF_DROP;
 626         }
 627
 628 /* Doesn't cover locally-generated broadcast, so not worth it. */
 629 #if 0
 630         /* Ignore broadcast: no `connection'. */
 631         if ((*pskb)->pkt_type == PACKET_BROADCAST) {
 632                 printk("Broadcast packet!\n");
 633                 return NF_ACCEPT;
 634         } else if (((*pskb)->nh.iph->daddr & htonl(0x000000FF))
 635                    == htonl(0x000000FF)) {
 636                 printk("Should bcast: %u.%u.%u.%u->%u.%u.%u.%u (sk=%p, ptype=%u)\n",
 637                        NIPQUAD((*pskb)->nh.iph->saddr),
 638                        NIPQUAD((*pskb)->nh.iph->daddr),
 639                        (*pskb)->sk, (*pskb)->pkt_type);
 640         }
 641 #endif
 642
 643         proto = ip_ct_find_proto((*pskb)->nh.iph->protocol);
 644
 645         /* It may be an special packet, error, unclean...
 646          * inverse of the return code tells to the netfilter
 647          * core what to do with the packet. */
 648         if (proto->error != NULL
 649             && (ret = proto->error(*pskb, &ctinfo, hooknum)) <= 0) {
 650                 CONNTRACK_STAT_INC(error);
 651                 CONNTRACK_STAT_INC(invalid);
 652                 return -ret;
 653         }
 654
 655         if (!(ct = resolve_normal_ct(*pskb, proto,&set_reply,hooknum,&ctinfo))) {
 656                 /* Not valid part of a connection */
 657                 CONNTRACK_STAT_INC(invalid);
 658                 return NF_ACCEPT;
 659         }
 660
 661         if (IS_ERR(ct)) {
 662                 /* Too stressed to deal. */
 663                 CONNTRACK_STAT_INC(drop);
 664                 return NF_DROP;
 665         }
 666
 667         IP_NF_ASSERT((*pskb)->nfct);
 668
 669         ret = proto->packet(ct, *pskb, ctinfo);
 670         if (ret < 0) {
 671                 /* Invalid: inverse of the return code tells
 672                  * the netfilter core what to do*/
 673                 nf_conntrack_put((*pskb)->nfct);
 674                 (*pskb)->nfct = NULL;
 675                 CONNTRACK_STAT_INC(invalid);
 676                 return -ret;
 677         }
 678
 679         if (set_reply)
 680                 set_bit(IPS_SEEN_REPLY_BIT, &ct->status);
 681
 682         return ret;
 683 }
 684
 685 int invert_tuplepr(struct ip_conntrack_tuple *inverse,
 686                    const struct ip_conntrack_tuple *orig)
 687 {
 688         return ip_ct_invert_tuple(inverse, orig,
 689                                   ip_ct_find_proto(orig->dst.protonum));
 690 }
 691
 692 /* Would two expected things clash? */
 693 static inline int expect_clash(const struct ip_conntrack_expect *a,
 694                                const struct ip_conntrack_expect *b)
 695 {
 696         /* Part covered by intersection of masks must be unequal,
 697            otherwise they clash */
 698         struct ip_conntrack_tuple intersect_mask
 699                 = { { a->mask.src.ip & b->mask.src.ip,
 700                       { a->mask.src.u.all & b->mask.src.u.all } },
 701                     { a->mask.dst.ip & b->mask.dst.ip,
 702                       { a->mask.dst.u.all & b->mask.dst.u.all },
 703                       a->mask.dst.protonum & b->mask.dst.protonum } };
 704
 705         return ip_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask);
 706 }
 707
 708 static inline int expect_matches(const struct ip_conntrack_expect *a,
 709                                  const struct ip_conntrack_expect *b)
 710 {
 711         return a->master == b->master
 712                 && ip_ct_tuple_equal(&a->tuple, &b->tuple)
 713                 && ip_ct_tuple_equal(&a->mask, &b->mask);
 714 }
 715
 716 /* Generally a bad idea to call this: could have matched already. */
 717 void ip_conntrack_unexpect_related(struct ip_conntrack_expect *exp)
 718 {
 719         struct ip_conntrack_expect *i;
 720
 721         write_lock_bh(&ip_conntrack_lock);
 722         /* choose the the oldest expectation to evict */
 723         list_for_each_entry_reverse(i, &ip_conntrack_expect_list, list) {
 724                 if (expect_matches(i, exp) && del_timer(&i->timeout)) {
 725                         unlink_expect(i);
 726                         write_unlock_bh(&ip_conntrack_lock);
 727                         ip_conntrack_expect_put(i);
 728                         return;
 729                 }
 730         }
 731         write_unlock_bh(&ip_conntrack_lock);
 732 }
 733
 734 struct ip_conntrack_expect *ip_conntrack_expect_alloc(struct ip_conntrack *me)
 735 {
 736         struct ip_conntrack_expect *new;
 737
 738         new = kmem_cache_alloc(ip_conntrack_expect_cachep, GFP_ATOMIC);
 739         if (!new) {
 740                 DEBUGP("expect_related: OOM allocating expect\n");
 741                 return NULL;
 742         }
 743         new->master = me;
 744         atomic_inc(&new->master->ct_general.use);
 745         atomic_set(&new->use, 1);
 746         return new;
 747 }
 748
 749 void ip_conntrack_expect_put(struct ip_conntrack_expect *exp)
 750 {
 751         if (atomic_dec_and_test(&exp->use)) {
 752                 ip_conntrack_put(exp->master);
 753                 kmem_cache_free(ip_conntrack_expect_cachep, exp);
 754         }
 755 }
 756
 757 static void ip_conntrack_expect_insert(struct ip_conntrack_expect *exp)
 758 {
 759         atomic_inc(&exp->use);
 760         exp->master->expecting++;
 761         list_add(&exp->list, &ip_conntrack_expect_list);
 762
 763         init_timer(&exp->timeout);
 764         exp->timeout.data = (unsigned long)exp;
 765         exp->timeout.function = expectation_timed_out;
 766         exp->timeout.expires = jiffies + exp->master->helper->timeout * HZ;
 767         add_timer(&exp->timeout);
 768
 769         CONNTRACK_STAT_INC(expect_create);
 770 }
 771
 772 /* Race with expectations being used means we could have none to find; OK. */
 773 static void evict_oldest_expect(struct ip_conntrack *master)
 774 {
 775         struct ip_conntrack_expect *i;
 776
 777         list_for_each_entry_reverse(i, &ip_conntrack_expect_list, list) {
 778                 if (i->master == master) {
 779                         if (del_timer(&i->timeout)) {
 780                                 unlink_expect(i);
 781                                 ip_conntrack_expect_put(i);
 782                         }
 783                         break;
 784                 }
 785         }
 786 }
 787
 788 static inline int refresh_timer(struct ip_conntrack_expect *i)
 789 {
 790         if (!del_timer(&i->timeout))
 791                 return 0;
 792
 793         i->timeout.expires = jiffies + i->master->helper->timeout*HZ;
 794         add_timer(&i->timeout);
 795         return 1;
 796 }
 797
 798 int ip_conntrack_expect_related(struct ip_conntrack_expect *expect)
 799 {
 800         struct ip_conntrack_expect *i;
 801         int ret;
 802
 803         DEBUGP("ip_conntrack_expect_related %p\n", related_to);
 804         DEBUGP("tuple: "); DUMP_TUPLE(&expect->tuple);
 805         DEBUGP("mask:  "); DUMP_TUPLE(&expect->mask);
 806
 807         write_lock_bh(&ip_conntrack_lock);
 808         list_for_each_entry(i, &ip_conntrack_expect_list, list) {
 809                 if (expect_matches(i, expect)) {
 810                         /* Refresh timer: if it's dying, ignore.. */
 811                         if (refresh_timer(i)) {
 812                                 ret = 0;
 813                                 goto out;
 814                         }
 815                 } else if (expect_clash(i, expect)) {
 816                         ret = -EBUSY;
 817                         goto out;
 818                 }
 819         }
 820
 821         /* Will be over limit? */
 822         if (expect->master->helper->max_expected &&
 823             expect->master->expecting >= expect->master->helper->max_expected)
 824                 evict_oldest_expect(expect->master);
 825
 826         ip_conntrack_expect_insert(expect);
 827         ret = 0;
 828 out:
 829         write_unlock_bh(&ip_conntrack_lock);
 830         return ret;
 831 }
 832
 833 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 834    implicitly racy: see __ip_conntrack_confirm */
 835 void ip_conntrack_alter_reply(struct ip_conntrack *conntrack,
 836                               const struct ip_conntrack_tuple *newreply)
 837 {
 838         write_lock_bh(&ip_conntrack_lock);
 839         /* Should be unconfirmed, so not in hash table yet */
 840         IP_NF_ASSERT(!is_confirmed(conntrack));
 841
 842         DEBUGP("Altering reply tuple of %p to ", conntrack);
 843         DUMP_TUPLE(newreply);
 844
 845         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 846         if (!conntrack->master && conntrack->expecting == 0)
 847                 conntrack->helper = ip_ct_find_helper(newreply);
 848         write_unlock_bh(&ip_conntrack_lock);
 849 }
 850
 851 int ip_conntrack_helper_register(struct ip_conntrack_helper *me)
 852 {
 853         BUG_ON(me->timeout == 0);
 854         write_lock_bh(&ip_conntrack_lock);
 855         list_prepend(&helpers, me);
 856         write_unlock_bh(&ip_conntrack_lock);
 857
 858         return 0;
 859 }
 860
 861 static inline int unhelp(struct ip_conntrack_tuple_hash *i,
 862                          const struct ip_conntrack_helper *me)
 863 {
 864         if (tuplehash_to_ctrack(i)->helper == me)
 865                 tuplehash_to_ctrack(i)->helper = NULL;
 866         return 0;
 867 }
 868
 869 void ip_conntrack_helper_unregister(struct ip_conntrack_helper *me)
 870 {
 871         unsigned int i;
 872         struct ip_conntrack_expect *exp, *tmp;
 873
 874         /* Need write lock here, to delete helper. */
 875         write_lock_bh(&ip_conntrack_lock);
 876         LIST_DELETE(&helpers, me);
 877
 878         /* Get rid of expectations */
 879         list_for_each_entry_safe(exp, tmp, &ip_conntrack_expect_list, list) {
 880                 if (exp->master->helper == me && del_timer(&exp->timeout)) {
 881                         unlink_expect(exp);
 882                         ip_conntrack_expect_put(exp);
 883                 }
 884         }
 885         /* Get rid of expecteds, set helpers to NULL. */
 886         LIST_FIND_W(&unconfirmed, unhelp, struct ip_conntrack_tuple_hash*, me);
 887         for (i = 0; i < ip_conntrack_htable_size; i++)
 888                 LIST_FIND_W(&ip_conntrack_hash[i], unhelp,
 889                             struct ip_conntrack_tuple_hash *, me);
 890         write_unlock_bh(&ip_conntrack_lock);
 891
 892         /* Someone could be still looking at the helper in a bh. */
 893         synchronize_net();
 894 }
 895
 896 static inline void ct_add_counters(struct ip_conntrack *ct,
 897                                    enum ip_conntrack_info ctinfo,
 898                                    const struct sk_buff *skb)
 899 {
 900 #ifdef CONFIG_IP_NF_CT_ACCT
 901         if (skb) {
 902                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 903                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 904                                         ntohs(skb->nh.iph->tot_len);
 905         }
 906 #endif
 907 }
 908
 909 /* Refresh conntrack for this many jiffies and do accounting (if skb != NULL) */
 910 void ip_ct_refresh_acct(struct ip_conntrack *ct,
 911                         enum ip_conntrack_info ctinfo,
 912                         const struct sk_buff *skb,
 913                         unsigned long extra_jiffies)
 914 {
 915         IP_NF_ASSERT(ct->timeout.data == (unsigned long)ct);
 916
 917         /* If not in hash table, timer will not be active yet */
 918         if (!is_confirmed(ct)) {
 919                 ct->timeout.expires = extra_jiffies;
 920                 ct_add_counters(ct, ctinfo, skb);
 921         } else {
 922                 write_lock_bh(&ip_conntrack_lock);
 923                 /* Need del_timer for race avoidance (may already be dying). */
 924                 if (del_timer(&ct->timeout)) {
 925                         ct->timeout.expires = jiffies + extra_jiffies;
 926                         add_timer(&ct->timeout);
 927                 }
 928                 ct_add_counters(ct, ctinfo, skb);
 929                 write_unlock_bh(&ip_conntrack_lock);
 930         }
 931 }
 932
 933 /* Returns new sk_buff, or NULL */
 934 struct sk_buff *
 935 ip_ct_gather_frags(struct sk_buff *skb, u_int32_t user)
 936 {
 937         skb_orphan(skb);
 938
 939         local_bh_disable();
 940         skb = ip_defrag(skb, user);
 941         local_bh_enable();
 942
 943         if (skb)
 944                 ip_send_check(skb->nh.iph);
 945         return skb;
 946 }
 947
 948 /* Used by ipt_REJECT. */
 949 static void ip_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
 950 {
 951         struct ip_conntrack *ct;
 952         enum ip_conntrack_info ctinfo;
 953
 954         /* This ICMP is in reverse direction to the packet which caused it */
 955         ct = ip_conntrack_get(skb, &ctinfo);
 956
 957         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
 958                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
 959         else
 960                 ctinfo = IP_CT_RELATED;
 961
 962         /* Attach to new skbuff, and increment count */
 963         nskb->nfct = &ct->ct_general;
 964         nskb->nfctinfo = ctinfo;
 965         nf_conntrack_get(nskb->nfct);
 966 }
 967
 968 static inline int
 969 do_iter(const struct ip_conntrack_tuple_hash *i,
 970         int (*iter)(struct ip_conntrack *i, void *data),
 971         void *data)
 972 {
 973         return iter(tuplehash_to_ctrack(i), data);
 974 }
 975
 976 /* Bring out ya dead! */
 977 static struct ip_conntrack_tuple_hash *
 978 get_next_corpse(int (*iter)(struct ip_conntrack *i, void *data),
 979                 void *data, unsigned int *bucket)
 980 {
 981         struct ip_conntrack_tuple_hash *h = NULL;
 982
 983         write_lock_bh(&ip_conntrack_lock);
 984         for (; *bucket < ip_conntrack_htable_size; (*bucket)++) {
 985                 h = LIST_FIND_W(&ip_conntrack_hash[*bucket], do_iter,
 986                                 struct ip_conntrack_tuple_hash *, iter, data);
 987                 if (h)
 988                         break;
 989         }
 990         if (!h)
 991                 h = LIST_FIND_W(&unconfirmed, do_iter,
 992                                 struct ip_conntrack_tuple_hash *, iter, data);
 993         if (h)
 994                 atomic_inc(&tuplehash_to_ctrack(h)->ct_general.use);
 995         write_unlock_bh(&ip_conntrack_lock);
 996
 997         return h;
 998 }
 999
1000 void
1001 ip_ct_iterate_cleanup(int (*iter)(struct ip_conntrack *i, void *), void *data)
1002 {
1003         struct ip_conntrack_tuple_hash *h;
1004         unsigned int bucket = 0;
1005
1006         while ((h = get_next_corpse(iter, data, &bucket)) != NULL) {
1007                 struct ip_conntrack *ct = tuplehash_to_ctrack(h);
1008                 /* Time to push up daises... */
1009                 if (del_timer(&ct->timeout))
1010                         death_by_timeout((unsigned long)ct);
1011                 /* ... else the timer will get him soon. */
1012
1013                 ip_conntrack_put(ct);
1014         }
1015 }
1016
1017 /* Fast function for those who don't want to parse /proc (and I don't
1018    blame them). */
1019 /* Reversing the socket's dst/src point of view gives us the reply
1020    mapping. */
1021 static int
1022 getorigdst(struct sock *sk, int optval, void __user *user, int *len)
1023 {
1024         struct inet_sock *inet = inet_sk(sk);
1025         struct ip_conntrack_tuple_hash *h;
1026         struct ip_conntrack_tuple tuple;
1027
1028         IP_CT_TUPLE_U_BLANK(&tuple);
1029         tuple.src.ip = inet->rcv_saddr;
1030         tuple.src.u.tcp.port = inet->sport;
1031         tuple.dst.ip = inet->daddr;
1032         tuple.dst.u.tcp.port = inet->dport;
1033         tuple.dst.protonum = IPPROTO_TCP;
1034
1035         /* We only do TCP at the moment: is there a better way? */
1036         if (strcmp(sk->sk_prot->name, "TCP")) {
1037                 DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
1038                 return -ENOPROTOOPT;
1039         }
1040
1041         if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
1042                 DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
1043                        *len, sizeof(struct sockaddr_in));
1044                 return -EINVAL;
1045         }
1046
1047         h = ip_conntrack_find_get(&tuple, NULL);
1048         if (h) {
1049                 struct sockaddr_in sin;
1050                 struct ip_conntrack *ct = tuplehash_to_ctrack(h);
1051
1052                 sin.sin_family = AF_INET;
1053                 sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
1054                         .tuple.dst.u.tcp.port;
1055                 sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
1056                         .tuple.dst.ip;
1057
1058                 DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
1059                        NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
1060                 ip_conntrack_put(ct);
1061                 if (copy_to_user(user, &sin, sizeof(sin)) != 0)
1062                         return -EFAULT;
1063                 else
1064                         return 0;
1065         }
1066         DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
1067                NIPQUAD(tuple.src.ip), ntohs(tuple.src.u.tcp.port),
1068                NIPQUAD(tuple.dst.ip), ntohs(tuple.dst.u.tcp.port));
1069         return -ENOENT;
1070 }
1071
1072 static struct nf_sockopt_ops so_getorigdst = {
1073         .pf             = PF_INET,
1074         .get_optmin     = SO_ORIGINAL_DST,
1075         .get_optmax     = SO_ORIGINAL_DST+1,
1076         .get            = &getorigdst,
1077 };
1078
1079 static int kill_all(struct ip_conntrack *i, void *data)
1080 {
1081         return 1;
1082 }
1083
1084 static void free_conntrack_hash(void)
1085 {
1086         if (ip_conntrack_vmalloc)
1087                 vfree(ip_conntrack_hash);
1088         else
1089                 free_pages((unsigned long)ip_conntrack_hash,
1090                            get_order(sizeof(struct list_head)
1091                                      * ip_conntrack_htable_size));
1092 }
1093
1094 /* Mishearing the voices in his head, our hero wonders how he's
1095    supposed to kill the mall. */
1096 void ip_conntrack_cleanup(void)
1097 {
1098         ip_ct_attach = NULL;
1099         /* This makes sure all current packets have passed through
1100            netfilter framework.  Roll on, two-stage module
1101            delete... */
1102         synchronize_net();
1103
1104  i_see_dead_people:
1105         ip_ct_iterate_cleanup(kill_all, NULL);
1106         if (atomic_read(&ip_conntrack_count) != 0) {
1107                 schedule();
1108                 goto i_see_dead_people;
1109         }
1110         /* wait until all references to ip_conntrack_untracked are dropped */
1111         while (atomic_read(&ip_conntrack_untracked.ct_general.use) > 1)
1112                 schedule();
1113
1114         kmem_cache_destroy(ip_conntrack_cachep);
1115         kmem_cache_destroy(ip_conntrack_expect_cachep);
1116         free_conntrack_hash();
1117         nf_unregister_sockopt(&so_getorigdst);
1118 }
1119
1120 static int hashsize;
1121 module_param(hashsize, int, 0400);
1122
1123 int __init ip_conntrack_init(void)
1124 {
1125         unsigned int i;
1126         int ret;
1127
1128         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1129          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1130         if (hashsize) {
1131                 ip_conntrack_htable_size = hashsize;
1132         } else {
1133                 ip_conntrack_htable_size
1134                         = (((num_physpages << PAGE_SHIFT) / 16384)
1135                            / sizeof(struct list_head));
1136                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1137                         ip_conntrack_htable_size = 8192;
1138                 if (ip_conntrack_htable_size < 16)
1139                         ip_conntrack_htable_size = 16;
1140         }
1141         ip_conntrack_max = 8 * ip_conntrack_htable_size;
1142
1143         printk("ip_conntrack version %s (%u buckets, %d max)"
1144                " - %Zd bytes per conntrack\n", IP_CONNTRACK_VERSION,
1145                ip_conntrack_htable_size, ip_conntrack_max,
1146                sizeof(struct ip_conntrack));
1147
1148         ret = nf_register_sockopt(&so_getorigdst);
1149         if (ret != 0) {
1150                 printk(KERN_ERR "Unable to register netfilter socket option\n");
1151                 return ret;
1152         }
1153
1154         /* AK: the hash table is twice as big than needed because it
1155            uses list_head.  it would be much nicer to caches to use a
1156            single pointer list head here. */
1157         ip_conntrack_vmalloc = 0;
1158         ip_conntrack_hash
1159                 =(void*)__get_free_pages(GFP_KERNEL,
1160                                          get_order(sizeof(struct list_head)
1161                                                    *ip_conntrack_htable_size));
1162         if (!ip_conntrack_hash) {
1163                 ip_conntrack_vmalloc = 1;
1164                 printk(KERN_WARNING "ip_conntrack: falling back to vmalloc.\n");
1165                 ip_conntrack_hash = vmalloc(sizeof(struct list_head)
1166                                             * ip_conntrack_htable_size);
1167         }
1168         if (!ip_conntrack_hash) {
1169                 printk(KERN_ERR "Unable to create ip_conntrack_hash\n");
1170                 goto err_unreg_sockopt;
1171         }
1172
1173         ip_conntrack_cachep = kmem_cache_create("ip_conntrack",
1174                                                 sizeof(struct ip_conntrack), 0,
1175                                                 0, NULL, NULL);
1176         if (!ip_conntrack_cachep) {
1177                 printk(KERN_ERR "Unable to create ip_conntrack slab cache\n");
1178                 goto err_free_hash;
1179         }
1180
1181         ip_conntrack_expect_cachep = kmem_cache_create("ip_conntrack_expect",
1182                                         sizeof(struct ip_conntrack_expect),
1183                                         0, 0, NULL, NULL);
1184         if (!ip_conntrack_expect_cachep) {
1185                 printk(KERN_ERR "Unable to create ip_expect slab cache\n");
1186                 goto err_free_conntrack_slab;
1187         }
1188
1189         /* Don't NEED lock here, but good form anyway. */
1190         write_lock_bh(&ip_conntrack_lock);
1191         for (i = 0; i < MAX_IP_CT_PROTO; i++)
1192                 ip_ct_protos[i] = &ip_conntrack_generic_protocol;
1193         /* Sew in builtin protocols. */
1194         ip_ct_protos[IPPROTO_TCP] = &ip_conntrack_protocol_tcp;
1195         ip_ct_protos[IPPROTO_UDP] = &ip_conntrack_protocol_udp;
1196         ip_ct_protos[IPPROTO_ICMP] = &ip_conntrack_protocol_icmp;
1197         write_unlock_bh(&ip_conntrack_lock);
1198
1199         for (i = 0; i < ip_conntrack_htable_size; i++)
1200                 INIT_LIST_HEAD(&ip_conntrack_hash[i]);
1201
1202         /* For use by ipt_REJECT */
1203         ip_ct_attach = ip_conntrack_attach;
1204
1205         /* Set up fake conntrack:
1206             - to never be deleted, not in any hashes */
1207         atomic_set(&ip_conntrack_untracked.ct_general.use, 1);
1208         /*  - and look it like as a confirmed connection */
1209         set_bit(IPS_CONFIRMED_BIT, &ip_conntrack_untracked.status);
1210
1211         return ret;
1212
1213 err_free_conntrack_slab:
1214         kmem_cache_destroy(ip_conntrack_cachep);
1215 err_free_hash:
1216         free_conntrack_hash();
1217 err_unreg_sockopt:
1218         nf_unregister_sockopt(&so_getorigdst);
1219
1220         return -ENOMEM;
1221 }