SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/netfilter/nf_conntrack_core.c

   1 /* Connection state tracking for netfilter.  This is separated from,
   2    but required by, the NAT layer; it can also be used by an iptables
   3    extension. */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
   7  * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * 23 Apr 2001: Harald Welte <laforge@gnumonks.org>
  14  *      - new API and handling of conntrack/nat helpers
  15  *      - now capable of multiple expectations for one master
  16  * 16 Jul 2002: Harald Welte <laforge@gnumonks.org>
  17  *      - add usage/reference counts to ip_conntrack_expect
  18  *      - export ip_conntrack[_expect]_{find_get,put} functions
  19  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  20  *      - generalize L3 protocol denendent part.
  21  * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  22  *      - add support various size of conntrack structures.
  23  * 26 Jan 2006: Harald Welte <laforge@netfilter.org>
  24  *      - restructure nf_conn (introduce nf_conn_help)
  25  *      - redesign 'features' how they were originally intended
  26  * 26 Feb 2006: Pablo Neira Ayuso <pablo@eurodev.net>
  27  *      - add support for L3 protocol module load on demand.
  28  *
  29  * Derived from net/ipv4/netfilter/ip_conntrack_core.c
  30  */
  31
  32 #include <linux/types.h>
  33 #include <linux/netfilter.h>
  34 #include <linux/module.h>
  35 #include <linux/skbuff.h>
  36 #include <linux/proc_fs.h>
  37 #include <linux/vmalloc.h>
  38 #include <linux/stddef.h>
  39 #include <linux/slab.h>
  40 #include <linux/random.h>
  41 #include <linux/jhash.h>
  42 #include <linux/err.h>
  43 #include <linux/percpu.h>
  44 #include <linux/moduleparam.h>
  45 #include <linux/notifier.h>
  46 #include <linux/kernel.h>
  47 #include <linux/netdevice.h>
  48 #include <linux/socket.h>
  49
  50 #include <net/netfilter/nf_conntrack.h>
  51 #include <net/netfilter/nf_conntrack_l3proto.h>
  52 #include <net/netfilter/nf_conntrack_l4proto.h>
  53 #include <net/netfilter/nf_conntrack_expect.h>
  54 #include <net/netfilter/nf_conntrack_helper.h>
  55 #include <net/netfilter/nf_conntrack_core.h>
  56
  57 #define NF_CONNTRACK_VERSION    "0.5.0"
  58
  59 #if 0
  60 #define DEBUGP printk
  61 #else
  62 #define DEBUGP(format, args...)
  63 #endif
  64
  65 DEFINE_RWLOCK(nf_conntrack_lock);
  66
  67 /* nf_conntrack_standalone needs this */
  68 atomic_t nf_conntrack_count = ATOMIC_INIT(0);
  69 EXPORT_SYMBOL_GPL(nf_conntrack_count);
  70
  71 void (*nf_conntrack_destroyed)(struct nf_conn *conntrack) = NULL;
  72 unsigned int nf_conntrack_htable_size __read_mostly;
  73 int nf_conntrack_max __read_mostly;
  74 EXPORT_SYMBOL_GPL(nf_conntrack_max);
  75 struct list_head *nf_conntrack_hash __read_mostly;
  76 struct nf_conn nf_conntrack_untracked __read_mostly;
  77 unsigned int nf_ct_log_invalid __read_mostly;
  78 LIST_HEAD(unconfirmed);
  79 static int nf_conntrack_vmalloc __read_mostly;
  80
  81 static unsigned int nf_conntrack_next_id;
  82
  83 DEFINE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  84 EXPORT_PER_CPU_SYMBOL(nf_conntrack_stat);
  85
  86 /*
  87  * This scheme offers various size of "struct nf_conn" dependent on
  88  * features(helper, nat, ...)
  89  */
  90
  91 #define NF_CT_FEATURES_NAMELEN  256
  92 static struct {
  93         /* name of slab cache. printed in /proc/slabinfo */
  94         char *name;
  95
  96         /* size of slab cache */
  97         size_t size;
  98
  99         /* slab cache pointer */
 100         kmem_cache_t *cachep;
 101
 102         /* allocated slab cache + modules which uses this slab cache */
 103         int use;
 104
 105 } nf_ct_cache[NF_CT_F_NUM];
 106
 107 /* protect members of nf_ct_cache except of "use" */
 108 DEFINE_RWLOCK(nf_ct_cache_lock);
 109
 110 /* This avoids calling kmem_cache_create() with same name simultaneously */
 111 static DEFINE_MUTEX(nf_ct_cache_mutex);
 112
 113 static int nf_conntrack_hash_rnd_initted;
 114 static unsigned int nf_conntrack_hash_rnd;
 115
 116 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple,
 117                                   unsigned int size, unsigned int rnd)
 118 {
 119         unsigned int a, b;
 120         a = jhash((void *)tuple->src.u3.all, sizeof(tuple->src.u3.all),
 121                   ((tuple->src.l3num) << 16) | tuple->dst.protonum);
 122         b = jhash((void *)tuple->dst.u3.all, sizeof(tuple->dst.u3.all),
 123                         (tuple->src.u.all << 16) | tuple->dst.u.all);
 124
 125         return jhash_2words(a, b, rnd) % size;
 126 }
 127
 128 static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple)
 129 {
 130         return __hash_conntrack(tuple, nf_conntrack_htable_size,
 131                                 nf_conntrack_hash_rnd);
 132 }
 133
 134 int nf_conntrack_register_cache(u_int32_t features, const char *name,
 135                                 size_t size)
 136 {
 137         int ret = 0;
 138         char *cache_name;
 139         kmem_cache_t *cachep;
 140
 141         DEBUGP("nf_conntrack_register_cache: features=0x%x, name=%s, size=%d\n",
 142                features, name, size);
 143
 144         if (features < NF_CT_F_BASIC || features >= NF_CT_F_NUM) {
 145                 DEBUGP("nf_conntrack_register_cache: invalid features.: 0x%x\n",
 146                         features);
 147                 return -EINVAL;
 148         }
 149
 150         mutex_lock(&nf_ct_cache_mutex);
 151
 152         write_lock_bh(&nf_ct_cache_lock);
 153         /* e.g: multiple helpers are loaded */
 154         if (nf_ct_cache[features].use > 0) {
 155                 DEBUGP("nf_conntrack_register_cache: already resisterd.\n");
 156                 if ((!strncmp(nf_ct_cache[features].name, name,
 157                               NF_CT_FEATURES_NAMELEN))
 158                     && nf_ct_cache[features].size == size) {
 159                         DEBUGP("nf_conntrack_register_cache: reusing.\n");
 160                         nf_ct_cache[features].use++;
 161                         ret = 0;
 162                 } else
 163                         ret = -EBUSY;
 164
 165                 write_unlock_bh(&nf_ct_cache_lock);
 166                 mutex_unlock(&nf_ct_cache_mutex);
 167                 return ret;
 168         }
 169         write_unlock_bh(&nf_ct_cache_lock);
 170
 171         /*
 172          * The memory space for name of slab cache must be alive until
 173          * cache is destroyed.
 174          */
 175         cache_name = kmalloc(sizeof(char)*NF_CT_FEATURES_NAMELEN, GFP_ATOMIC);
 176         if (cache_name == NULL) {
 177                 DEBUGP("nf_conntrack_register_cache: can't alloc cache_name\n");
 178                 ret = -ENOMEM;
 179                 goto out_up_mutex;
 180         }
 181
 182         if (strlcpy(cache_name, name, NF_CT_FEATURES_NAMELEN)
 183                                                 >= NF_CT_FEATURES_NAMELEN) {
 184                 printk("nf_conntrack_register_cache: name too long\n");
 185                 ret = -EINVAL;
 186                 goto out_free_name;
 187         }
 188
 189         cachep = kmem_cache_create(cache_name, size, 0, 0,
 190                                    NULL, NULL);
 191         if (!cachep) {
 192                 printk("nf_conntrack_register_cache: Can't create slab cache "
 193                        "for the features = 0x%x\n", features);
 194                 ret = -ENOMEM;
 195                 goto out_free_name;
 196         }
 197
 198         write_lock_bh(&nf_ct_cache_lock);
 199         nf_ct_cache[features].use = 1;
 200         nf_ct_cache[features].size = size;
 201         nf_ct_cache[features].cachep = cachep;
 202         nf_ct_cache[features].name = cache_name;
 203         write_unlock_bh(&nf_ct_cache_lock);
 204
 205         goto out_up_mutex;
 206
 207 out_free_name:
 208         kfree(cache_name);
 209 out_up_mutex:
 210         mutex_unlock(&nf_ct_cache_mutex);
 211         return ret;
 212 }
 213
 214 /* FIXME: In the current, only nf_conntrack_cleanup() can call this function. */
 215 void nf_conntrack_unregister_cache(u_int32_t features)
 216 {
 217         kmem_cache_t *cachep;
 218         char *name;
 219
 220         /*
 221          * This assures that kmem_cache_create() isn't called before destroying
 222          * slab cache.
 223          */
 224         DEBUGP("nf_conntrack_unregister_cache: 0x%04x\n", features);
 225         mutex_lock(&nf_ct_cache_mutex);
 226
 227         write_lock_bh(&nf_ct_cache_lock);
 228         if (--nf_ct_cache[features].use > 0) {
 229                 write_unlock_bh(&nf_ct_cache_lock);
 230                 mutex_unlock(&nf_ct_cache_mutex);
 231                 return;
 232         }
 233         cachep = nf_ct_cache[features].cachep;
 234         name = nf_ct_cache[features].name;
 235         nf_ct_cache[features].cachep = NULL;
 236         nf_ct_cache[features].name = NULL;
 237         nf_ct_cache[features].size = 0;
 238         write_unlock_bh(&nf_ct_cache_lock);
 239
 240         synchronize_net();
 241
 242         kmem_cache_destroy(cachep);
 243         kfree(name);
 244
 245         mutex_unlock(&nf_ct_cache_mutex);
 246 }
 247
 248 int
 249 nf_ct_get_tuple(const struct sk_buff *skb,
 250                 unsigned int nhoff,
 251                 unsigned int dataoff,
 252                 u_int16_t l3num,
 253                 u_int8_t protonum,
 254                 struct nf_conntrack_tuple *tuple,
 255                 const struct nf_conntrack_l3proto *l3proto,
 256                 const struct nf_conntrack_l4proto *l4proto)
 257 {
 258         NF_CT_TUPLE_U_BLANK(tuple);
 259
 260         tuple->src.l3num = l3num;
 261         if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0)
 262                 return 0;
 263
 264         tuple->dst.protonum = protonum;
 265         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 266
 267         return l4proto->pkt_to_tuple(skb, dataoff, tuple);
 268 }
 269
 270 int
 271 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 272                    const struct nf_conntrack_tuple *orig,
 273                    const struct nf_conntrack_l3proto *l3proto,
 274                    const struct nf_conntrack_l4proto *l4proto)
 275 {
 276         NF_CT_TUPLE_U_BLANK(inverse);
 277
 278         inverse->src.l3num = orig->src.l3num;
 279         if (l3proto->invert_tuple(inverse, orig) == 0)
 280                 return 0;
 281
 282         inverse->dst.dir = !orig->dst.dir;
 283
 284         inverse->dst.protonum = orig->dst.protonum;
 285         return l4proto->invert_tuple(inverse, orig);
 286 }
 287
 288 static void
 289 clean_from_lists(struct nf_conn *ct)
 290 {
 291         DEBUGP("clean_from_lists(%p)\n", ct);
 292         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 293         list_del(&ct->tuplehash[IP_CT_DIR_REPLY].list);
 294
 295         /* Destroy all pending expectations */
 296         nf_ct_remove_expectations(ct);
 297 }
 298
 299 static void
 300 destroy_conntrack(struct nf_conntrack *nfct)
 301 {
 302         struct nf_conn *ct = (struct nf_conn *)nfct;
 303         struct nf_conn_help *help = nfct_help(ct);
 304         struct nf_conntrack_l3proto *l3proto;
 305         struct nf_conntrack_l4proto *l4proto;
 306
 307         DEBUGP("destroy_conntrack(%p)\n", ct);
 308         NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
 309         NF_CT_ASSERT(!timer_pending(&ct->timeout));
 310
 311         nf_conntrack_event(IPCT_DESTROY, ct);
 312         set_bit(IPS_DYING_BIT, &ct->status);
 313
 314         if (help && help->helper && help->helper->destroy)
 315                 help->helper->destroy(ct);
 316
 317         /* To make sure we don't get any weird locking issues here:
 318          * destroy_conntrack() MUST NOT be called with a write lock
 319          * to nf_conntrack_lock!!! -HW */
 320         l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num);
 321         if (l3proto && l3proto->destroy)
 322                 l3proto->destroy(ct);
 323
 324         l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum);
 325         if (l4proto && l4proto->destroy)
 326                 l4proto->destroy(ct);
 327
 328         if (nf_conntrack_destroyed)
 329                 nf_conntrack_destroyed(ct);
 330
 331         write_lock_bh(&nf_conntrack_lock);
 332         /* Expectations will have been removed in clean_from_lists,
 333          * except TFTP can create an expectation on the first packet,
 334          * before connection is in the list, so we need to clean here,
 335          * too. */
 336         nf_ct_remove_expectations(ct);
 337
 338         /* We overload first tuple to link into unconfirmed list. */
 339         if (!nf_ct_is_confirmed(ct)) {
 340                 BUG_ON(list_empty(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list));
 341                 list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 342         }
 343
 344         NF_CT_STAT_INC(delete);
 345         write_unlock_bh(&nf_conntrack_lock);
 346
 347         if (ct->master)
 348                 nf_ct_put(ct->master);
 349
 350         DEBUGP("destroy_conntrack: returning ct=%p to slab\n", ct);
 351         nf_conntrack_free(ct);
 352 }
 353
 354 static void death_by_timeout(unsigned long ul_conntrack)
 355 {
 356         struct nf_conn *ct = (void *)ul_conntrack;
 357
 358         write_lock_bh(&nf_conntrack_lock);
 359         /* Inside lock so preempt is disabled on module removal path.
 360          * Otherwise we can get spurious warnings. */
 361         NF_CT_STAT_INC(delete_list);
 362         clean_from_lists(ct);
 363         write_unlock_bh(&nf_conntrack_lock);
 364         nf_ct_put(ct);
 365 }
 366
 367 struct nf_conntrack_tuple_hash *
 368 __nf_conntrack_find(const struct nf_conntrack_tuple *tuple,
 369                     const struct nf_conn *ignored_conntrack)
 370 {
 371         struct nf_conntrack_tuple_hash *h;
 372         unsigned int hash = hash_conntrack(tuple);
 373
 374         list_for_each_entry(h, &nf_conntrack_hash[hash], list) {
 375                 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack &&
 376                     nf_ct_tuple_equal(tuple, &h->tuple)) {
 377                         NF_CT_STAT_INC(found);
 378                         return h;
 379                 }
 380                 NF_CT_STAT_INC(searched);
 381         }
 382
 383         return NULL;
 384 }
 385
 386 /* Find a connection corresponding to a tuple. */
 387 struct nf_conntrack_tuple_hash *
 388 nf_conntrack_find_get(const struct nf_conntrack_tuple *tuple,
 389                       const struct nf_conn *ignored_conntrack)
 390 {
 391         struct nf_conntrack_tuple_hash *h;
 392
 393         read_lock_bh(&nf_conntrack_lock);
 394         h = __nf_conntrack_find(tuple, ignored_conntrack);
 395         if (h)
 396                 atomic_inc(&nf_ct_tuplehash_to_ctrack(h)->ct_general.use);
 397         read_unlock_bh(&nf_conntrack_lock);
 398
 399         return h;
 400 }
 401
 402 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 403                                        unsigned int hash,
 404                                        unsigned int repl_hash)
 405 {
 406         ct->id = ++nf_conntrack_next_id;
 407         list_add(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list,
 408                  &nf_conntrack_hash[hash]);
 409         list_add(&ct->tuplehash[IP_CT_DIR_REPLY].list,
 410                  &nf_conntrack_hash[repl_hash]);
 411 }
 412
 413 void nf_conntrack_hash_insert(struct nf_conn *ct)
 414 {
 415         unsigned int hash, repl_hash;
 416
 417         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 418         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 419
 420         write_lock_bh(&nf_conntrack_lock);
 421         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 422         write_unlock_bh(&nf_conntrack_lock);
 423 }
 424
 425 /* Confirm a connection given skb; places it in hash table */
 426 int
 427 __nf_conntrack_confirm(struct sk_buff **pskb)
 428 {
 429         unsigned int hash, repl_hash;
 430         struct nf_conntrack_tuple_hash *h;
 431         struct nf_conn *ct;
 432         struct nf_conn_help *help;
 433         enum ip_conntrack_info ctinfo;
 434
 435         ct = nf_ct_get(*pskb, &ctinfo);
 436
 437         /* ipt_REJECT uses nf_conntrack_attach to attach related
 438            ICMP/TCP RST packets in other direction.  Actual packet
 439            which created connection will be IP_CT_NEW or for an
 440            expected connection, IP_CT_RELATED. */
 441         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 442                 return NF_ACCEPT;
 443
 444         hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 445         repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 446
 447         /* We're not in hash table, and we refuse to set up related
 448            connections for unconfirmed conns.  But packet copies and
 449            REJECT will give spurious warnings here. */
 450         /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 451
 452         /* No external references means noone else could have
 453            confirmed us. */
 454         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 455         DEBUGP("Confirming conntrack %p\n", ct);
 456
 457         write_lock_bh(&nf_conntrack_lock);
 458
 459         /* See if there's one in the list already, including reverse:
 460            NAT could have grabbed it without realizing, since we're
 461            not in the hash.  If there is, we lost race. */
 462         list_for_each_entry(h, &nf_conntrack_hash[hash], list)
 463                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 464                                       &h->tuple))
 465                         goto out;
 466         list_for_each_entry(h, &nf_conntrack_hash[repl_hash], list)
 467                 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 468                                       &h->tuple))
 469                         goto out;
 470
 471         /* Remove from unconfirmed list */
 472         list_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].list);
 473
 474         __nf_conntrack_hash_insert(ct, hash, repl_hash);
 475         /* Timer relative to confirmation time, not original
 476            setting time, otherwise we'd get timer wrap in
 477            weird delay cases. */
 478         ct->timeout.expires += jiffies;
 479         add_timer(&ct->timeout);
 480         atomic_inc(&ct->ct_general.use);
 481         set_bit(IPS_CONFIRMED_BIT, &ct->status);
 482         NF_CT_STAT_INC(insert);
 483         write_unlock_bh(&nf_conntrack_lock);
 484         help = nfct_help(ct);
 485         if (help && help->helper)
 486                 nf_conntrack_event_cache(IPCT_HELPER, *pskb);
 487 #ifdef CONFIG_NF_NAT_NEEDED
 488         if (test_bit(IPS_SRC_NAT_DONE_BIT, &ct->status) ||
 489             test_bit(IPS_DST_NAT_DONE_BIT, &ct->status))
 490                 nf_conntrack_event_cache(IPCT_NATINFO, *pskb);
 491 #endif
 492         nf_conntrack_event_cache(master_ct(ct) ?
 493                                  IPCT_RELATED : IPCT_NEW, *pskb);
 494         return NF_ACCEPT;
 495
 496 out:
 497         NF_CT_STAT_INC(insert_failed);
 498         write_unlock_bh(&nf_conntrack_lock);
 499         return NF_DROP;
 500 }
 501
 502 /* Returns true if a connection correspondings to the tuple (required
 503    for NAT). */
 504 int
 505 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
 506                          const struct nf_conn *ignored_conntrack)
 507 {
 508         struct nf_conntrack_tuple_hash *h;
 509
 510         read_lock_bh(&nf_conntrack_lock);
 511         h = __nf_conntrack_find(tuple, ignored_conntrack);
 512         read_unlock_bh(&nf_conntrack_lock);
 513
 514         return h != NULL;
 515 }
 516
 517 /* There's a small race here where we may free a just-assured
 518    connection.  Too bad: we're in trouble anyway. */
 519 static int early_drop(struct list_head *chain)
 520 {
 521         /* Traverse backwards: gives us oldest, which is roughly LRU */
 522         struct nf_conntrack_tuple_hash *h;
 523         struct nf_conn *ct = NULL, *tmp;
 524         int dropped = 0;
 525
 526         read_lock_bh(&nf_conntrack_lock);
 527         list_for_each_entry_reverse(h, chain, list) {
 528                 tmp = nf_ct_tuplehash_to_ctrack(h);
 529                 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) {
 530                         ct = tmp;
 531                         atomic_inc(&ct->ct_general.use);
 532                         break;
 533                 }
 534         }
 535         read_unlock_bh(&nf_conntrack_lock);
 536
 537         if (!ct)
 538                 return dropped;
 539
 540         if (del_timer(&ct->timeout)) {
 541                 death_by_timeout((unsigned long)ct);
 542                 dropped = 1;
 543                 NF_CT_STAT_INC(early_drop);
 544         }
 545         nf_ct_put(ct);
 546         return dropped;
 547 }
 548
 549 static struct nf_conn *
 550 __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 551                      const struct nf_conntrack_tuple *repl,
 552                      const struct nf_conntrack_l3proto *l3proto,
 553                      u_int32_t features)
 554 {
 555         struct nf_conn *conntrack = NULL;
 556         struct nf_conntrack_helper *helper;
 557
 558         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
 559                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
 560                 nf_conntrack_hash_rnd_initted = 1;
 561         }
 562
 563         /* We don't want any race condition at early drop stage */
 564         atomic_inc(&nf_conntrack_count);
 565
 566         if (nf_conntrack_max
 567             && atomic_read(&nf_conntrack_count) > nf_conntrack_max) {
 568                 unsigned int hash = hash_conntrack(orig);
 569                 /* Try dropping from this hash chain. */
 570                 if (!early_drop(&nf_conntrack_hash[hash])) {
 571                         atomic_dec(&nf_conntrack_count);
 572                         if (net_ratelimit())
 573                                 printk(KERN_WARNING
 574                                        "nf_conntrack: table full, dropping"
 575                                        " packet.\n");
 576                         return ERR_PTR(-ENOMEM);
 577                 }
 578         }
 579
 580         /*  find features needed by this conntrack. */
 581         features |= l3proto->get_features(orig);
 582
 583         /* FIXME: protect helper list per RCU */
 584         read_lock_bh(&nf_conntrack_lock);
 585         helper = __nf_ct_helper_find(repl);
 586         /* NAT might want to assign a helper later */
 587         if (helper || features & NF_CT_F_NAT)
 588                 features |= NF_CT_F_HELP;
 589         read_unlock_bh(&nf_conntrack_lock);
 590
 591         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 592
 593         read_lock_bh(&nf_ct_cache_lock);
 594
 595         if (unlikely(!nf_ct_cache[features].use)) {
 596                 DEBUGP("nf_conntrack_alloc: not supported features = 0x%x\n",
 597                         features);
 598                 goto out;
 599         }
 600
 601         conntrack = kmem_cache_alloc(nf_ct_cache[features].cachep, GFP_ATOMIC);
 602         if (conntrack == NULL) {
 603                 DEBUGP("nf_conntrack_alloc: Can't alloc conntrack from cache\n");
 604                 goto out;
 605         }
 606
 607         memset(conntrack, 0, nf_ct_cache[features].size);
 608         conntrack->features = features;
 609         atomic_set(&conntrack->ct_general.use, 1);
 610         conntrack->ct_general.destroy = destroy_conntrack;
 611         conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
 612         conntrack->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
 613         /* Don't set timer yet: wait for confirmation */
 614         init_timer(&conntrack->timeout);
 615         conntrack->timeout.data = (unsigned long)conntrack;
 616         conntrack->timeout.function = death_by_timeout;
 617         read_unlock_bh(&nf_ct_cache_lock);
 618
 619         return conntrack;
 620 out:
 621         read_unlock_bh(&nf_ct_cache_lock);
 622         atomic_dec(&nf_conntrack_count);
 623         return conntrack;
 624 }
 625
 626 struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 627                                    const struct nf_conntrack_tuple *repl)
 628 {
 629         struct nf_conntrack_l3proto *l3proto;
 630
 631         l3proto = __nf_ct_l3proto_find(orig->src.l3num);
 632         return __nf_conntrack_alloc(orig, repl, l3proto, 0);
 633 }
 634
 635 void nf_conntrack_free(struct nf_conn *conntrack)
 636 {
 637         u_int32_t features = conntrack->features;
 638         NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
 639         DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
 640                conntrack);
 641         kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
 642         atomic_dec(&nf_conntrack_count);
 643 }
 644
 645 /* Allocate a new conntrack: we return -ENOMEM if classification
 646    failed due to stress.  Otherwise it really is unclassifiable. */
 647 static struct nf_conntrack_tuple_hash *
 648 init_conntrack(const struct nf_conntrack_tuple *tuple,
 649                struct nf_conntrack_l3proto *l3proto,
 650                struct nf_conntrack_l4proto *l4proto,
 651                struct sk_buff *skb,
 652                unsigned int dataoff)
 653 {
 654         struct nf_conn *conntrack;
 655         struct nf_conntrack_tuple repl_tuple;
 656         struct nf_conntrack_expect *exp;
 657         u_int32_t features = 0;
 658
 659         if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) {
 660                 DEBUGP("Can't invert tuple.\n");
 661                 return NULL;
 662         }
 663
 664         read_lock_bh(&nf_conntrack_lock);
 665         exp = __nf_conntrack_expect_find(tuple);
 666         if (exp && exp->helper)
 667                 features = NF_CT_F_HELP;
 668         read_unlock_bh(&nf_conntrack_lock);
 669
 670         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
 671         if (conntrack == NULL || IS_ERR(conntrack)) {
 672                 DEBUGP("Can't allocate conntrack.\n");
 673                 return (struct nf_conntrack_tuple_hash *)conntrack;
 674         }
 675
 676         if (!l4proto->new(conntrack, skb, dataoff)) {
 677                 nf_conntrack_free(conntrack);
 678                 DEBUGP("init conntrack: can't track with proto module\n");
 679                 return NULL;
 680         }
 681
 682         write_lock_bh(&nf_conntrack_lock);
 683         exp = find_expectation(tuple);
 684
 685         if (exp) {
 686                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
 687                         conntrack, exp);
 688                 /* Welcome, Mr. Bond.  We've been expecting you... */
 689                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
 690                 conntrack->master = exp->master;
 691                 if (exp->helper)
 692                         nfct_help(conntrack)->helper = exp->helper;
 693 #ifdef CONFIG_NF_CONNTRACK_MARK
 694                 conntrack->mark = exp->master->mark;
 695 #endif
 696 #ifdef CONFIG_NF_CONNTRACK_SECMARK
 697                 conntrack->secmark = exp->master->secmark;
 698 #endif
 699                 nf_conntrack_get(&conntrack->master->ct_general);
 700                 NF_CT_STAT_INC(expect_new);
 701         } else {
 702                 struct nf_conn_help *help = nfct_help(conntrack);
 703
 704                 if (help)
 705                         help->helper = __nf_ct_helper_find(&repl_tuple);
 706                 NF_CT_STAT_INC(new);
 707         }
 708
 709         /* Overload tuple linked list to put us in unconfirmed list. */
 710         list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);
 711
 712         write_unlock_bh(&nf_conntrack_lock);
 713
 714         if (exp) {
 715                 if (exp->expectfn)
 716                         exp->expectfn(conntrack, exp);
 717                 nf_conntrack_expect_put(exp);
 718         }
 719
 720         return &conntrack->tuplehash[IP_CT_DIR_ORIGINAL];
 721 }
 722
 723 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */
 724 static inline struct nf_conn *
 725 resolve_normal_ct(struct sk_buff *skb,
 726                   unsigned int dataoff,
 727                   u_int16_t l3num,
 728                   u_int8_t protonum,
 729                   struct nf_conntrack_l3proto *l3proto,
 730                   struct nf_conntrack_l4proto *l4proto,
 731                   int *set_reply,
 732                   enum ip_conntrack_info *ctinfo)
 733 {
 734         struct nf_conntrack_tuple tuple;
 735         struct nf_conntrack_tuple_hash *h;
 736         struct nf_conn *ct;
 737
 738         if (!nf_ct_get_tuple(skb, (unsigned int)(skb->nh.raw - skb->data),
 739                              dataoff, l3num, protonum, &tuple, l3proto,
 740                              l4proto)) {
 741                 DEBUGP("resolve_normal_ct: Can't get tuple\n");
 742                 return NULL;
 743         }
 744
 745         /* look for tuple match */
 746         h = nf_conntrack_find_get(&tuple, NULL);
 747         if (!h) {
 748                 h = init_conntrack(&tuple, l3proto, l4proto, skb, dataoff);
 749                 if (!h)
 750                         return NULL;
 751                 if (IS_ERR(h))
 752                         return (void *)h;
 753         }
 754         ct = nf_ct_tuplehash_to_ctrack(h);
 755
 756         /* It exists; we have (non-exclusive) reference. */
 757         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
 758                 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY;
 759                 /* Please set reply bit if this packet OK */
 760                 *set_reply = 1;
 761         } else {
 762                 /* Once we've had two way comms, always ESTABLISHED. */
 763                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
 764                         DEBUGP("nf_conntrack_in: normal packet for %p\n", ct);
 765                         *ctinfo = IP_CT_ESTABLISHED;
 766                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
 767                         DEBUGP("nf_conntrack_in: related packet for %p\n", ct);
 768                         *ctinfo = IP_CT_RELATED;
 769                 } else {
 770                         DEBUGP("nf_conntrack_in: new packet for %p\n", ct);
 771                         *ctinfo = IP_CT_NEW;
 772                 }
 773                 *set_reply = 0;
 774         }
 775         skb->nfct = &ct->ct_general;
 776         skb->nfctinfo = *ctinfo;
 777         return ct;
 778 }
 779
 780 unsigned int
 781 nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
 782 {
 783         struct nf_conn *ct;
 784         enum ip_conntrack_info ctinfo;
 785         struct nf_conntrack_l3proto *l3proto;
 786         struct nf_conntrack_l4proto *l4proto;
 787         unsigned int dataoff;
 788         u_int8_t protonum;
 789         int set_reply = 0;
 790         int ret;
 791
 792         /* Previously seen (loopback or untracked)?  Ignore. */
 793         if ((*pskb)->nfct) {
 794                 NF_CT_STAT_INC(ignore);
 795                 return NF_ACCEPT;
 796         }
 797
 798         l3proto = __nf_ct_l3proto_find((u_int16_t)pf);
 799         if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) {
 800                 DEBUGP("not prepared to track yet or error occured\n");
 801                 return -ret;
 802         }
 803
 804         l4proto = __nf_ct_l4proto_find((u_int16_t)pf, protonum);
 805
 806         /* It may be an special packet, error, unclean...
 807          * inverse of the return code tells to the netfilter
 808          * core what to do with the packet. */
 809         if (l4proto->error != NULL &&
 810             (ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
 811                 NF_CT_STAT_INC(error);
 812                 NF_CT_STAT_INC(invalid);
 813                 return -ret;
 814         }
 815
 816         ct = resolve_normal_ct(*pskb, dataoff, pf, protonum, l3proto, l4proto,
 817                                &set_reply, &ctinfo);
 818         if (!ct) {
 819                 /* Not valid part of a connection */
 820                 NF_CT_STAT_INC(invalid);
 821                 return NF_ACCEPT;
 822         }
 823
 824         if (IS_ERR(ct)) {
 825                 /* Too stressed to deal. */
 826                 NF_CT_STAT_INC(drop);
 827                 return NF_DROP;
 828         }
 829
 830         NF_CT_ASSERT((*pskb)->nfct);
 831
 832         ret = l4proto->packet(ct, *pskb, dataoff, ctinfo, pf, hooknum);
 833         if (ret < 0) {
 834                 /* Invalid: inverse of the return code tells
 835                  * the netfilter core what to do */
 836                 DEBUGP("nf_conntrack_in: Can't track with proto module\n");
 837                 nf_conntrack_put((*pskb)->nfct);
 838                 (*pskb)->nfct = NULL;
 839                 NF_CT_STAT_INC(invalid);
 840                 return -ret;
 841         }
 842
 843         if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
 844                 nf_conntrack_event_cache(IPCT_STATUS, *pskb);
 845
 846         return ret;
 847 }
 848
 849 int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
 850                          const struct nf_conntrack_tuple *orig)
 851 {
 852         return nf_ct_invert_tuple(inverse, orig,
 853                                   __nf_ct_l3proto_find(orig->src.l3num),
 854                                   __nf_ct_l4proto_find(orig->src.l3num,
 855                                                      orig->dst.protonum));
 856 }
 857
 858 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
 859    implicitly racy: see __nf_conntrack_confirm */
 860 void nf_conntrack_alter_reply(struct nf_conn *ct,
 861                               const struct nf_conntrack_tuple *newreply)
 862 {
 863         struct nf_conn_help *help = nfct_help(ct);
 864
 865         write_lock_bh(&nf_conntrack_lock);
 866         /* Should be unconfirmed, so not in hash table yet */
 867         NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
 868
 869         DEBUGP("Altering reply tuple of %p to ", ct);
 870         NF_CT_DUMP_TUPLE(newreply);
 871
 872         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
 873         if (!ct->master && help && help->expecting == 0)
 874                 help->helper = __nf_ct_helper_find(newreply);
 875         write_unlock_bh(&nf_conntrack_lock);
 876 }
 877
 878 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
 879 void __nf_ct_refresh_acct(struct nf_conn *ct,
 880                           enum ip_conntrack_info ctinfo,
 881                           const struct sk_buff *skb,
 882                           unsigned long extra_jiffies,
 883                           int do_acct)
 884 {
 885         int event = 0;
 886
 887         NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
 888         NF_CT_ASSERT(skb);
 889
 890         write_lock_bh(&nf_conntrack_lock);
 891
 892         /* Only update if this is not a fixed timeout */
 893         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) {
 894                 write_unlock_bh(&nf_conntrack_lock);
 895                 return;
 896         }
 897
 898         /* If not in hash table, timer will not be active yet */
 899         if (!nf_ct_is_confirmed(ct)) {
 900                 ct->timeout.expires = extra_jiffies;
 901                 event = IPCT_REFRESH;
 902         } else {
 903                 unsigned long newtime = jiffies + extra_jiffies;
 904
 905                 /* Only update the timeout if the new timeout is at least
 906                    HZ jiffies from the old timeout. Need del_timer for race
 907                    avoidance (may already be dying). */
 908                 if (newtime - ct->timeout.expires >= HZ
 909                     && del_timer(&ct->timeout)) {
 910                         ct->timeout.expires = newtime;
 911                         add_timer(&ct->timeout);
 912                         event = IPCT_REFRESH;
 913                 }
 914         }
 915
 916 #ifdef CONFIG_NF_CT_ACCT
 917         if (do_acct) {
 918                 ct->counters[CTINFO2DIR(ctinfo)].packets++;
 919                 ct->counters[CTINFO2DIR(ctinfo)].bytes +=
 920                         skb->len - (unsigned int)(skb->nh.raw - skb->data);
 921
 922                 if ((ct->counters[CTINFO2DIR(ctinfo)].packets & 0x80000000)
 923                     || (ct->counters[CTINFO2DIR(ctinfo)].bytes & 0x80000000))
 924                         event |= IPCT_COUNTER_FILLING;
 925         }
 926 #endif
 927
 928         write_unlock_bh(&nf_conntrack_lock);
 929
 930         /* must be unlocked when calling event cache */
 931         if (event)
 932                 nf_conntrack_event_cache(event, skb);
 933 }
 934
 935 #if defined(CONFIG_NF_CT_NETLINK) || \
 936     defined(CONFIG_NF_CT_NETLINK_MODULE)
 937
 938 #include <linux/netfilter/nfnetlink.h>
 939 #include <linux/netfilter/nfnetlink_conntrack.h>
 940 #include <linux/mutex.h>
 941
 942
 943 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be
 944  * in ip_conntrack_core, since we don't want the protocols to autoload
 945  * or depend on ctnetlink */
 946 int nf_ct_port_tuple_to_nfattr(struct sk_buff *skb,
 947                                const struct nf_conntrack_tuple *tuple)
 948 {
 949         NFA_PUT(skb, CTA_PROTO_SRC_PORT, sizeof(u_int16_t),
 950                 &tuple->src.u.tcp.port);
 951         NFA_PUT(skb, CTA_PROTO_DST_PORT, sizeof(u_int16_t),
 952                 &tuple->dst.u.tcp.port);
 953         return 0;
 954
 955 nfattr_failure:
 956         return -1;
 957 }
 958
 959 static const size_t cta_min_proto[CTA_PROTO_MAX] = {
 960         [CTA_PROTO_SRC_PORT-1]  = sizeof(u_int16_t),
 961         [CTA_PROTO_DST_PORT-1]  = sizeof(u_int16_t)
 962 };
 963
 964 int nf_ct_port_nfattr_to_tuple(struct nfattr *tb[],
 965                                struct nf_conntrack_tuple *t)
 966 {
 967         if (!tb[CTA_PROTO_SRC_PORT-1] || !tb[CTA_PROTO_DST_PORT-1])
 968                 return -EINVAL;
 969
 970         if (nfattr_bad_size(tb, CTA_PROTO_MAX, cta_min_proto))
 971                 return -EINVAL;
 972
 973         t->src.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_SRC_PORT-1]);
 974         t->dst.u.tcp.port = *(__be16 *)NFA_DATA(tb[CTA_PROTO_DST_PORT-1]);
 975
 976         return 0;
 977 }
 978 #endif
 979
 980 /* Used by ipt_REJECT and ip6t_REJECT. */
 981 void __nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb)
 982 {
 983         struct nf_conn *ct;
 984         enum ip_conntrack_info ctinfo;
 985
 986         /* This ICMP is in reverse direction to the packet which caused it */
 987         ct = nf_ct_get(skb, &ctinfo);
 988         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
 989                 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY;
 990         else
 991                 ctinfo = IP_CT_RELATED;
 992
 993         /* Attach to new skbuff, and increment count */
 994         nskb->nfct = &ct->ct_general;
 995         nskb->nfctinfo = ctinfo;
 996         nf_conntrack_get(nskb->nfct);
 997 }
 998
 999 static inline int
1000 do_iter(const struct nf_conntrack_tuple_hash *i,
1001         int (*iter)(struct nf_conn *i, void *data),
1002         void *data)
1003 {
1004         return iter(nf_ct_tuplehash_to_ctrack(i), data);
1005 }
1006
1007 /* Bring out ya dead! */
1008 static struct nf_conn *
1009 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
1010                 void *data, unsigned int *bucket)
1011 {
1012         struct nf_conntrack_tuple_hash *h;
1013         struct nf_conn *ct;
1014
1015         write_lock_bh(&nf_conntrack_lock);
1016         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
1017                 list_for_each_entry(h, &nf_conntrack_hash[*bucket], list) {
1018                         ct = nf_ct_tuplehash_to_ctrack(h);
1019                         if (iter(ct, data))
1020                                 goto found;
1021                 }
1022         }
1023         list_for_each_entry(h, &unconfirmed, list) {
1024                 ct = nf_ct_tuplehash_to_ctrack(h);
1025                 if (iter(ct, data))
1026                         goto found;
1027         }
1028         write_unlock_bh(&nf_conntrack_lock);
1029         return NULL;
1030 found:
1031         atomic_inc(&ct->ct_general.use);
1032         write_unlock_bh(&nf_conntrack_lock);
1033         return ct;
1034 }
1035
1036 void
1037 nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), void *data)
1038 {
1039         struct nf_conn *ct;
1040         unsigned int bucket = 0;
1041
1042         while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
1043                 /* Time to push up daises... */
1044                 if (del_timer(&ct->timeout))
1045                         death_by_timeout((unsigned long)ct);
1046                 /* ... else the timer will get him soon. */
1047
1048                 nf_ct_put(ct);
1049         }
1050 }
1051
1052 static int kill_all(struct nf_conn *i, void *data)
1053 {
1054         return 1;
1055 }
1056
1057 static void free_conntrack_hash(struct list_head *hash, int vmalloced, int size)
1058 {
1059         if (vmalloced)
1060                 vfree(hash);
1061         else
1062                 free_pages((unsigned long)hash,
1063                            get_order(sizeof(struct list_head) * size));
1064 }
1065
1066 void nf_conntrack_flush()
1067 {
1068         nf_ct_iterate_cleanup(kill_all, NULL);
1069 }
1070
1071 /* Mishearing the voices in his head, our hero wonders how he's
1072    supposed to kill the mall. */
1073 void nf_conntrack_cleanup(void)
1074 {
1075         int i;
1076
1077         ip_ct_attach = NULL;
1078
1079         /* This makes sure all current packets have passed through
1080            netfilter framework.  Roll on, two-stage module
1081            delete... */
1082         synchronize_net();
1083
1084         nf_ct_event_cache_flush();
1085  i_see_dead_people:
1086         nf_conntrack_flush();
1087         if (atomic_read(&nf_conntrack_count) != 0) {
1088                 schedule();
1089                 goto i_see_dead_people;
1090         }
1091         /* wait until all references to nf_conntrack_untracked are dropped */
1092         while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1)
1093                 schedule();
1094
1095         for (i = 0; i < NF_CT_F_NUM; i++) {
1096                 if (nf_ct_cache[i].use == 0)
1097                         continue;
1098
1099                 NF_CT_ASSERT(nf_ct_cache[i].use == 1);
1100                 nf_ct_cache[i].use = 1;
1101                 nf_conntrack_unregister_cache(i);
1102         }
1103         kmem_cache_destroy(nf_conntrack_expect_cachep);
1104         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1105                             nf_conntrack_htable_size);
1106
1107         nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_generic);
1108
1109         /* free l3proto protocol tables */
1110         for (i = 0; i < PF_MAX; i++)
1111                 if (nf_ct_protos[i]) {
1112                         kfree(nf_ct_protos[i]);
1113                         nf_ct_protos[i] = NULL;
1114                 }
1115 }
1116
1117 static struct list_head *alloc_hashtable(int size, int *vmalloced)
1118 {
1119         struct list_head *hash;
1120         unsigned int i;
1121
1122         *vmalloced = 0;
1123         hash = (void*)__get_free_pages(GFP_KERNEL,
1124                                        get_order(sizeof(struct list_head)
1125                                                  * size));
1126         if (!hash) {
1127                 *vmalloced = 1;
1128                 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n");
1129                 hash = vmalloc(sizeof(struct list_head) * size);
1130         }
1131
1132         if (hash)
1133                 for (i = 0; i < size; i++)
1134                         INIT_LIST_HEAD(&hash[i]);
1135
1136         return hash;
1137 }
1138
1139 int set_hashsize(const char *val, struct kernel_param *kp)
1140 {
1141         int i, bucket, hashsize, vmalloced;
1142         int old_vmalloced, old_size;
1143         int rnd;
1144         struct list_head *hash, *old_hash;
1145         struct nf_conntrack_tuple_hash *h;
1146
1147         /* On boot, we can set this without any fancy locking. */
1148         if (!nf_conntrack_htable_size)
1149                 return param_set_uint(val, kp);
1150
1151         hashsize = simple_strtol(val, NULL, 0);
1152         if (!hashsize)
1153                 return -EINVAL;
1154
1155         hash = alloc_hashtable(hashsize, &vmalloced);
1156         if (!hash)
1157                 return -ENOMEM;
1158
1159         /* We have to rehahs for the new table anyway, so we also can
1160          * use a newrandom seed */
1161         get_random_bytes(&rnd, 4);
1162
1163         write_lock_bh(&nf_conntrack_lock);
1164         for (i = 0; i < nf_conntrack_htable_size; i++) {
1165                 while (!list_empty(&nf_conntrack_hash[i])) {
1166                         h = list_entry(nf_conntrack_hash[i].next,
1167                                        struct nf_conntrack_tuple_hash, list);
1168                         list_del(&h->list);
1169                         bucket = __hash_conntrack(&h->tuple, hashsize, rnd);
1170                         list_add_tail(&h->list, &hash[bucket]);
1171                 }
1172         }
1173         old_size = nf_conntrack_htable_size;
1174         old_vmalloced = nf_conntrack_vmalloc;
1175         old_hash = nf_conntrack_hash;
1176
1177         nf_conntrack_htable_size = hashsize;
1178         nf_conntrack_vmalloc = vmalloced;
1179         nf_conntrack_hash = hash;
1180         nf_conntrack_hash_rnd = rnd;
1181         write_unlock_bh(&nf_conntrack_lock);
1182
1183         free_conntrack_hash(old_hash, old_vmalloced, old_size);
1184         return 0;
1185 }
1186
1187 module_param_call(hashsize, set_hashsize, param_get_uint,
1188                   &nf_conntrack_htable_size, 0600);
1189
1190 int __init nf_conntrack_init(void)
1191 {
1192         unsigned int i;
1193         int ret;
1194
1195         /* Idea from tcp.c: use 1/16384 of memory.  On i386: 32MB
1196          * machine has 256 buckets.  >= 1GB machines have 8192 buckets. */
1197         if (!nf_conntrack_htable_size) {
1198                 nf_conntrack_htable_size
1199                         = (((num_physpages << PAGE_SHIFT) / 16384)
1200                            / sizeof(struct list_head));
1201                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
1202                         nf_conntrack_htable_size = 8192;
1203                 if (nf_conntrack_htable_size < 16)
1204                         nf_conntrack_htable_size = 16;
1205         }
1206         nf_conntrack_max = 8 * nf_conntrack_htable_size;
1207
1208         printk("nf_conntrack version %s (%u buckets, %d max)\n",
1209                NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
1210                nf_conntrack_max);
1211
1212         nf_conntrack_hash = alloc_hashtable(nf_conntrack_htable_size,
1213                                             &nf_conntrack_vmalloc);
1214         if (!nf_conntrack_hash) {
1215                 printk(KERN_ERR "Unable to create nf_conntrack_hash\n");
1216                 goto err_out;
1217         }
1218
1219         ret = nf_conntrack_register_cache(NF_CT_F_BASIC, "nf_conntrack:basic",
1220                                           sizeof(struct nf_conn));
1221         if (ret < 0) {
1222                 printk(KERN_ERR "Unable to create nf_conn slab cache\n");
1223                 goto err_free_hash;
1224         }
1225
1226         nf_conntrack_expect_cachep = kmem_cache_create("nf_conntrack_expect",
1227                                         sizeof(struct nf_conntrack_expect),
1228                                         0, 0, NULL, NULL);
1229         if (!nf_conntrack_expect_cachep) {
1230                 printk(KERN_ERR "Unable to create nf_expect slab cache\n");
1231                 goto err_free_conntrack_slab;
1232         }
1233
1234         ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_generic);
1235         if (ret < 0)
1236                 goto out_free_expect_slab;
1237
1238         /* Don't NEED lock here, but good form anyway. */
1239         write_lock_bh(&nf_conntrack_lock);
1240         for (i = 0; i < AF_MAX; i++)
1241                 nf_ct_l3protos[i] = &nf_conntrack_l3proto_generic;
1242         write_unlock_bh(&nf_conntrack_lock);
1243
1244         /* For use by REJECT target */
1245         ip_ct_attach = __nf_conntrack_attach;
1246
1247         /* Set up fake conntrack:
1248             - to never be deleted, not in any hashes */
1249         atomic_set(&nf_conntrack_untracked.ct_general.use, 1);
1250         /*  - and look it like as a confirmed connection */
1251         set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status);
1252
1253         return ret;
1254
1255 out_free_expect_slab:
1256         kmem_cache_destroy(nf_conntrack_expect_cachep);
1257 err_free_conntrack_slab:
1258         nf_conntrack_unregister_cache(NF_CT_F_BASIC);
1259 err_free_hash:
1260         free_conntrack_hash(nf_conntrack_hash, nf_conntrack_vmalloc,
1261                             nf_conntrack_htable_size);
1262 err_out:
1263         return -ENOMEM;
1264 }