nf_conntrack_core.c revision 4481374ce88ba8f460c8b89f2572027bd27057d0
1/* Connection state tracking for netfilter. This is separated from, 2 but required by, the NAT layer; it can also be used by an iptables 3 extension. */ 4 5/* (C) 1999-2001 Paul `Rusty' Russell 6 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> 7 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14#include <linux/types.h> 15#include <linux/netfilter.h> 16#include <linux/module.h> 17#include <linux/skbuff.h> 18#include <linux/proc_fs.h> 19#include <linux/vmalloc.h> 20#include <linux/stddef.h> 21#include <linux/slab.h> 22#include <linux/random.h> 23#include <linux/jhash.h> 24#include <linux/err.h> 25#include <linux/percpu.h> 26#include <linux/moduleparam.h> 27#include <linux/notifier.h> 28#include <linux/kernel.h> 29#include <linux/netdevice.h> 30#include <linux/socket.h> 31#include <linux/mm.h> 32#include <linux/rculist_nulls.h> 33 34#include <net/netfilter/nf_conntrack.h> 35#include <net/netfilter/nf_conntrack_l3proto.h> 36#include <net/netfilter/nf_conntrack_l4proto.h> 37#include <net/netfilter/nf_conntrack_expect.h> 38#include <net/netfilter/nf_conntrack_helper.h> 39#include <net/netfilter/nf_conntrack_core.h> 40#include <net/netfilter/nf_conntrack_extend.h> 41#include <net/netfilter/nf_conntrack_acct.h> 42#include <net/netfilter/nf_conntrack_ecache.h> 43#include <net/netfilter/nf_nat.h> 44#include <net/netfilter/nf_nat_core.h> 45 46#define NF_CONNTRACK_VERSION "0.5.0" 47 48int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 49 enum nf_nat_manip_type manip, 50 const struct nlattr *attr) __read_mostly; 51EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 52 53DEFINE_SPINLOCK(nf_conntrack_lock); 54EXPORT_SYMBOL_GPL(nf_conntrack_lock); 55 56unsigned int nf_conntrack_htable_size __read_mostly; 57EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 58 59unsigned int nf_conntrack_max __read_mostly; 60EXPORT_SYMBOL_GPL(nf_conntrack_max); 61 62struct nf_conn nf_conntrack_untracked __read_mostly; 63EXPORT_SYMBOL_GPL(nf_conntrack_untracked); 64 65static struct kmem_cache *nf_conntrack_cachep __read_mostly; 66 67static int nf_conntrack_hash_rnd_initted; 68static unsigned int nf_conntrack_hash_rnd; 69 70static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 71 unsigned int size, unsigned int rnd) 72{ 73 unsigned int n; 74 u_int32_t h; 75 76 /* The direction must be ignored, so we hash everything up to the 77 * destination ports (which is a multiple of 4) and treat the last 78 * three bytes manually. 79 */ 80 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 81 h = jhash2((u32 *)tuple, n, 82 rnd ^ (((__force __u16)tuple->dst.u.all << 16) | 83 tuple->dst.protonum)); 84 85 return ((u64)h * size) >> 32; 86} 87 88static inline u_int32_t hash_conntrack(const struct nf_conntrack_tuple *tuple) 89{ 90 return __hash_conntrack(tuple, nf_conntrack_htable_size, 91 nf_conntrack_hash_rnd); 92} 93 94bool 95nf_ct_get_tuple(const struct sk_buff *skb, 96 unsigned int nhoff, 97 unsigned int dataoff, 98 u_int16_t l3num, 99 u_int8_t protonum, 100 struct nf_conntrack_tuple *tuple, 101 const struct nf_conntrack_l3proto *l3proto, 102 const struct nf_conntrack_l4proto *l4proto) 103{ 104 memset(tuple, 0, sizeof(*tuple)); 105 106 tuple->src.l3num = l3num; 107 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 108 return false; 109 110 tuple->dst.protonum = protonum; 111 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 112 113 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 114} 115EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 116 117bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 118 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 119{ 120 struct nf_conntrack_l3proto *l3proto; 121 struct nf_conntrack_l4proto *l4proto; 122 unsigned int protoff; 123 u_int8_t protonum; 124 int ret; 125 126 rcu_read_lock(); 127 128 l3proto = __nf_ct_l3proto_find(l3num); 129 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 130 if (ret != NF_ACCEPT) { 131 rcu_read_unlock(); 132 return false; 133 } 134 135 l4proto = __nf_ct_l4proto_find(l3num, protonum); 136 137 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 138 l3proto, l4proto); 139 140 rcu_read_unlock(); 141 return ret; 142} 143EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 144 145bool 146nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 147 const struct nf_conntrack_tuple *orig, 148 const struct nf_conntrack_l3proto *l3proto, 149 const struct nf_conntrack_l4proto *l4proto) 150{ 151 memset(inverse, 0, sizeof(*inverse)); 152 153 inverse->src.l3num = orig->src.l3num; 154 if (l3proto->invert_tuple(inverse, orig) == 0) 155 return false; 156 157 inverse->dst.dir = !orig->dst.dir; 158 159 inverse->dst.protonum = orig->dst.protonum; 160 return l4proto->invert_tuple(inverse, orig); 161} 162EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 163 164static void 165clean_from_lists(struct nf_conn *ct) 166{ 167 pr_debug("clean_from_lists(%p)\n", ct); 168 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 169 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 170 171 /* Destroy all pending expectations */ 172 nf_ct_remove_expectations(ct); 173} 174 175static void 176destroy_conntrack(struct nf_conntrack *nfct) 177{ 178 struct nf_conn *ct = (struct nf_conn *)nfct; 179 struct net *net = nf_ct_net(ct); 180 struct nf_conntrack_l4proto *l4proto; 181 182 pr_debug("destroy_conntrack(%p)\n", ct); 183 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 184 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 185 186 /* To make sure we don't get any weird locking issues here: 187 * destroy_conntrack() MUST NOT be called with a write lock 188 * to nf_conntrack_lock!!! -HW */ 189 rcu_read_lock(); 190 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 191 if (l4proto && l4proto->destroy) 192 l4proto->destroy(ct); 193 194 rcu_read_unlock(); 195 196 spin_lock_bh(&nf_conntrack_lock); 197 /* Expectations will have been removed in clean_from_lists, 198 * except TFTP can create an expectation on the first packet, 199 * before connection is in the list, so we need to clean here, 200 * too. */ 201 nf_ct_remove_expectations(ct); 202 203 /* We overload first tuple to link into unconfirmed list. */ 204 if (!nf_ct_is_confirmed(ct)) { 205 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 206 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 207 } 208 209 NF_CT_STAT_INC(net, delete); 210 spin_unlock_bh(&nf_conntrack_lock); 211 212 if (ct->master) 213 nf_ct_put(ct->master); 214 215 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 216 nf_conntrack_free(ct); 217} 218 219void nf_ct_delete_from_lists(struct nf_conn *ct) 220{ 221 struct net *net = nf_ct_net(ct); 222 223 nf_ct_helper_destroy(ct); 224 spin_lock_bh(&nf_conntrack_lock); 225 /* Inside lock so preempt is disabled on module removal path. 226 * Otherwise we can get spurious warnings. */ 227 NF_CT_STAT_INC(net, delete_list); 228 clean_from_lists(ct); 229 spin_unlock_bh(&nf_conntrack_lock); 230} 231EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 232 233static void death_by_event(unsigned long ul_conntrack) 234{ 235 struct nf_conn *ct = (void *)ul_conntrack; 236 struct net *net = nf_ct_net(ct); 237 238 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 239 /* bad luck, let's retry again */ 240 ct->timeout.expires = jiffies + 241 (random32() % net->ct.sysctl_events_retry_timeout); 242 add_timer(&ct->timeout); 243 return; 244 } 245 /* we've got the event delivered, now it's dying */ 246 set_bit(IPS_DYING_BIT, &ct->status); 247 spin_lock(&nf_conntrack_lock); 248 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 249 spin_unlock(&nf_conntrack_lock); 250 nf_ct_put(ct); 251} 252 253void nf_ct_insert_dying_list(struct nf_conn *ct) 254{ 255 struct net *net = nf_ct_net(ct); 256 257 /* add this conntrack to the dying list */ 258 spin_lock_bh(&nf_conntrack_lock); 259 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 260 &net->ct.dying); 261 spin_unlock_bh(&nf_conntrack_lock); 262 /* set a new timer to retry event delivery */ 263 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); 264 ct->timeout.expires = jiffies + 265 (random32() % net->ct.sysctl_events_retry_timeout); 266 add_timer(&ct->timeout); 267} 268EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); 269 270static void death_by_timeout(unsigned long ul_conntrack) 271{ 272 struct nf_conn *ct = (void *)ul_conntrack; 273 274 if (!test_bit(IPS_DYING_BIT, &ct->status) && 275 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 276 /* destroy event was not delivered */ 277 nf_ct_delete_from_lists(ct); 278 nf_ct_insert_dying_list(ct); 279 return; 280 } 281 set_bit(IPS_DYING_BIT, &ct->status); 282 nf_ct_delete_from_lists(ct); 283 nf_ct_put(ct); 284} 285 286/* 287 * Warning : 288 * - Caller must take a reference on returned object 289 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 290 * OR 291 * - Caller must lock nf_conntrack_lock before calling this function 292 */ 293struct nf_conntrack_tuple_hash * 294__nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple) 295{ 296 struct nf_conntrack_tuple_hash *h; 297 struct hlist_nulls_node *n; 298 unsigned int hash = hash_conntrack(tuple); 299 300 /* Disable BHs the entire time since we normally need to disable them 301 * at least once for the stats anyway. 302 */ 303 local_bh_disable(); 304begin: 305 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 306 if (nf_ct_tuple_equal(tuple, &h->tuple)) { 307 NF_CT_STAT_INC(net, found); 308 local_bh_enable(); 309 return h; 310 } 311 NF_CT_STAT_INC(net, searched); 312 } 313 /* 314 * if the nulls value we got at the end of this lookup is 315 * not the expected one, we must restart lookup. 316 * We probably met an item that was moved to another chain. 317 */ 318 if (get_nulls_value(n) != hash) 319 goto begin; 320 local_bh_enable(); 321 322 return NULL; 323} 324EXPORT_SYMBOL_GPL(__nf_conntrack_find); 325 326/* Find a connection corresponding to a tuple. */ 327struct nf_conntrack_tuple_hash * 328nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple) 329{ 330 struct nf_conntrack_tuple_hash *h; 331 struct nf_conn *ct; 332 333 rcu_read_lock(); 334begin: 335 h = __nf_conntrack_find(net, tuple); 336 if (h) { 337 ct = nf_ct_tuplehash_to_ctrack(h); 338 if (unlikely(nf_ct_is_dying(ct) || 339 !atomic_inc_not_zero(&ct->ct_general.use))) 340 h = NULL; 341 else { 342 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) { 343 nf_ct_put(ct); 344 goto begin; 345 } 346 } 347 } 348 rcu_read_unlock(); 349 350 return h; 351} 352EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 353 354static void __nf_conntrack_hash_insert(struct nf_conn *ct, 355 unsigned int hash, 356 unsigned int repl_hash) 357{ 358 struct net *net = nf_ct_net(ct); 359 360 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 361 &net->ct.hash[hash]); 362 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 363 &net->ct.hash[repl_hash]); 364} 365 366void nf_conntrack_hash_insert(struct nf_conn *ct) 367{ 368 unsigned int hash, repl_hash; 369 370 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 371 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); 372 373 __nf_conntrack_hash_insert(ct, hash, repl_hash); 374} 375EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert); 376 377/* Confirm a connection given skb; places it in hash table */ 378int 379__nf_conntrack_confirm(struct sk_buff *skb) 380{ 381 unsigned int hash, repl_hash; 382 struct nf_conntrack_tuple_hash *h; 383 struct nf_conn *ct; 384 struct nf_conn_help *help; 385 struct hlist_nulls_node *n; 386 enum ip_conntrack_info ctinfo; 387 struct net *net; 388 389 ct = nf_ct_get(skb, &ctinfo); 390 net = nf_ct_net(ct); 391 392 /* ipt_REJECT uses nf_conntrack_attach to attach related 393 ICMP/TCP RST packets in other direction. Actual packet 394 which created connection will be IP_CT_NEW or for an 395 expected connection, IP_CT_RELATED. */ 396 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 397 return NF_ACCEPT; 398 399 hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 400 repl_hash = hash_conntrack(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); 401 402 /* We're not in hash table, and we refuse to set up related 403 connections for unconfirmed conns. But packet copies and 404 REJECT will give spurious warnings here. */ 405 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 406 407 /* No external references means noone else could have 408 confirmed us. */ 409 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 410 pr_debug("Confirming conntrack %p\n", ct); 411 412 spin_lock_bh(&nf_conntrack_lock); 413 414 /* See if there's one in the list already, including reverse: 415 NAT could have grabbed it without realizing, since we're 416 not in the hash. If there is, we lost race. */ 417 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 418 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 419 &h->tuple)) 420 goto out; 421 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 422 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 423 &h->tuple)) 424 goto out; 425 426 /* Remove from unconfirmed list */ 427 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 428 429 /* Timer relative to confirmation time, not original 430 setting time, otherwise we'd get timer wrap in 431 weird delay cases. */ 432 ct->timeout.expires += jiffies; 433 add_timer(&ct->timeout); 434 atomic_inc(&ct->ct_general.use); 435 set_bit(IPS_CONFIRMED_BIT, &ct->status); 436 437 /* Since the lookup is lockless, hash insertion must be done after 438 * starting the timer and setting the CONFIRMED bit. The RCU barriers 439 * guarantee that no other CPU can find the conntrack before the above 440 * stores are visible. 441 */ 442 __nf_conntrack_hash_insert(ct, hash, repl_hash); 443 NF_CT_STAT_INC(net, insert); 444 spin_unlock_bh(&nf_conntrack_lock); 445 446 help = nfct_help(ct); 447 if (help && help->helper) 448 nf_conntrack_event_cache(IPCT_HELPER, ct); 449 450 nf_conntrack_event_cache(master_ct(ct) ? 451 IPCT_RELATED : IPCT_NEW, ct); 452 return NF_ACCEPT; 453 454out: 455 NF_CT_STAT_INC(net, insert_failed); 456 spin_unlock_bh(&nf_conntrack_lock); 457 return NF_DROP; 458} 459EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 460 461/* Returns true if a connection correspondings to the tuple (required 462 for NAT). */ 463int 464nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 465 const struct nf_conn *ignored_conntrack) 466{ 467 struct net *net = nf_ct_net(ignored_conntrack); 468 struct nf_conntrack_tuple_hash *h; 469 struct hlist_nulls_node *n; 470 unsigned int hash = hash_conntrack(tuple); 471 472 /* Disable BHs the entire time since we need to disable them at 473 * least once for the stats anyway. 474 */ 475 rcu_read_lock_bh(); 476 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 477 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack && 478 nf_ct_tuple_equal(tuple, &h->tuple)) { 479 NF_CT_STAT_INC(net, found); 480 rcu_read_unlock_bh(); 481 return 1; 482 } 483 NF_CT_STAT_INC(net, searched); 484 } 485 rcu_read_unlock_bh(); 486 487 return 0; 488} 489EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 490 491#define NF_CT_EVICTION_RANGE 8 492 493/* There's a small race here where we may free a just-assured 494 connection. Too bad: we're in trouble anyway. */ 495static noinline int early_drop(struct net *net, unsigned int hash) 496{ 497 /* Use oldest entry, which is roughly LRU */ 498 struct nf_conntrack_tuple_hash *h; 499 struct nf_conn *ct = NULL, *tmp; 500 struct hlist_nulls_node *n; 501 unsigned int i, cnt = 0; 502 int dropped = 0; 503 504 rcu_read_lock(); 505 for (i = 0; i < nf_conntrack_htable_size; i++) { 506 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 507 hnnode) { 508 tmp = nf_ct_tuplehash_to_ctrack(h); 509 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 510 ct = tmp; 511 cnt++; 512 } 513 514 if (ct && unlikely(nf_ct_is_dying(ct) || 515 !atomic_inc_not_zero(&ct->ct_general.use))) 516 ct = NULL; 517 if (ct || cnt >= NF_CT_EVICTION_RANGE) 518 break; 519 hash = (hash + 1) % nf_conntrack_htable_size; 520 } 521 rcu_read_unlock(); 522 523 if (!ct) 524 return dropped; 525 526 if (del_timer(&ct->timeout)) { 527 death_by_timeout((unsigned long)ct); 528 dropped = 1; 529 NF_CT_STAT_INC_ATOMIC(net, early_drop); 530 } 531 nf_ct_put(ct); 532 return dropped; 533} 534 535struct nf_conn *nf_conntrack_alloc(struct net *net, 536 const struct nf_conntrack_tuple *orig, 537 const struct nf_conntrack_tuple *repl, 538 gfp_t gfp) 539{ 540 struct nf_conn *ct; 541 542 if (unlikely(!nf_conntrack_hash_rnd_initted)) { 543 get_random_bytes(&nf_conntrack_hash_rnd, 544 sizeof(nf_conntrack_hash_rnd)); 545 nf_conntrack_hash_rnd_initted = 1; 546 } 547 548 /* We don't want any race condition at early drop stage */ 549 atomic_inc(&net->ct.count); 550 551 if (nf_conntrack_max && 552 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 553 unsigned int hash = hash_conntrack(orig); 554 if (!early_drop(net, hash)) { 555 atomic_dec(&net->ct.count); 556 if (net_ratelimit()) 557 printk(KERN_WARNING 558 "nf_conntrack: table full, dropping" 559 " packet.\n"); 560 return ERR_PTR(-ENOMEM); 561 } 562 } 563 564 /* 565 * Do not use kmem_cache_zalloc(), as this cache uses 566 * SLAB_DESTROY_BY_RCU. 567 */ 568 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp); 569 if (ct == NULL) { 570 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); 571 atomic_dec(&net->ct.count); 572 return ERR_PTR(-ENOMEM); 573 } 574 /* 575 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 576 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 577 */ 578 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 579 sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 580 spin_lock_init(&ct->lock); 581 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 582 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 583 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 584 ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL; 585 /* Don't set timer yet: wait for confirmation */ 586 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 587#ifdef CONFIG_NET_NS 588 ct->ct_net = net; 589#endif 590 591 /* 592 * changes to lookup keys must be done before setting refcnt to 1 593 */ 594 smp_wmb(); 595 atomic_set(&ct->ct_general.use, 1); 596 return ct; 597} 598EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 599 600void nf_conntrack_free(struct nf_conn *ct) 601{ 602 struct net *net = nf_ct_net(ct); 603 604 nf_ct_ext_destroy(ct); 605 atomic_dec(&net->ct.count); 606 nf_ct_ext_free(ct); 607 kmem_cache_free(nf_conntrack_cachep, ct); 608} 609EXPORT_SYMBOL_GPL(nf_conntrack_free); 610 611/* Allocate a new conntrack: we return -ENOMEM if classification 612 failed due to stress. Otherwise it really is unclassifiable. */ 613static struct nf_conntrack_tuple_hash * 614init_conntrack(struct net *net, 615 const struct nf_conntrack_tuple *tuple, 616 struct nf_conntrack_l3proto *l3proto, 617 struct nf_conntrack_l4proto *l4proto, 618 struct sk_buff *skb, 619 unsigned int dataoff) 620{ 621 struct nf_conn *ct; 622 struct nf_conn_help *help; 623 struct nf_conntrack_tuple repl_tuple; 624 struct nf_conntrack_expect *exp; 625 626 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 627 pr_debug("Can't invert tuple.\n"); 628 return NULL; 629 } 630 631 ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC); 632 if (IS_ERR(ct)) { 633 pr_debug("Can't allocate conntrack.\n"); 634 return (struct nf_conntrack_tuple_hash *)ct; 635 } 636 637 if (!l4proto->new(ct, skb, dataoff)) { 638 nf_conntrack_free(ct); 639 pr_debug("init conntrack: can't track with proto module\n"); 640 return NULL; 641 } 642 643 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 644 nf_ct_ecache_ext_add(ct, GFP_ATOMIC); 645 646 spin_lock_bh(&nf_conntrack_lock); 647 exp = nf_ct_find_expectation(net, tuple); 648 if (exp) { 649 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 650 ct, exp); 651 /* Welcome, Mr. Bond. We've been expecting you... */ 652 __set_bit(IPS_EXPECTED_BIT, &ct->status); 653 ct->master = exp->master; 654 if (exp->helper) { 655 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 656 if (help) 657 rcu_assign_pointer(help->helper, exp->helper); 658 } 659 660#ifdef CONFIG_NF_CONNTRACK_MARK 661 ct->mark = exp->master->mark; 662#endif 663#ifdef CONFIG_NF_CONNTRACK_SECMARK 664 ct->secmark = exp->master->secmark; 665#endif 666 nf_conntrack_get(&ct->master->ct_general); 667 NF_CT_STAT_INC(net, expect_new); 668 } else { 669 __nf_ct_try_assign_helper(ct, GFP_ATOMIC); 670 NF_CT_STAT_INC(net, new); 671 } 672 673 /* Overload tuple linked list to put us in unconfirmed list. */ 674 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 675 &net->ct.unconfirmed); 676 677 spin_unlock_bh(&nf_conntrack_lock); 678 679 if (exp) { 680 if (exp->expectfn) 681 exp->expectfn(ct, exp); 682 nf_ct_expect_put(exp); 683 } 684 685 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 686} 687 688/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 689static inline struct nf_conn * 690resolve_normal_ct(struct net *net, 691 struct sk_buff *skb, 692 unsigned int dataoff, 693 u_int16_t l3num, 694 u_int8_t protonum, 695 struct nf_conntrack_l3proto *l3proto, 696 struct nf_conntrack_l4proto *l4proto, 697 int *set_reply, 698 enum ip_conntrack_info *ctinfo) 699{ 700 struct nf_conntrack_tuple tuple; 701 struct nf_conntrack_tuple_hash *h; 702 struct nf_conn *ct; 703 704 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 705 dataoff, l3num, protonum, &tuple, l3proto, 706 l4proto)) { 707 pr_debug("resolve_normal_ct: Can't get tuple\n"); 708 return NULL; 709 } 710 711 /* look for tuple match */ 712 h = nf_conntrack_find_get(net, &tuple); 713 if (!h) { 714 h = init_conntrack(net, &tuple, l3proto, l4proto, skb, dataoff); 715 if (!h) 716 return NULL; 717 if (IS_ERR(h)) 718 return (void *)h; 719 } 720 ct = nf_ct_tuplehash_to_ctrack(h); 721 722 /* It exists; we have (non-exclusive) reference. */ 723 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 724 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY; 725 /* Please set reply bit if this packet OK */ 726 *set_reply = 1; 727 } else { 728 /* Once we've had two way comms, always ESTABLISHED. */ 729 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 730 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 731 *ctinfo = IP_CT_ESTABLISHED; 732 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 733 pr_debug("nf_conntrack_in: related packet for %p\n", 734 ct); 735 *ctinfo = IP_CT_RELATED; 736 } else { 737 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 738 *ctinfo = IP_CT_NEW; 739 } 740 *set_reply = 0; 741 } 742 skb->nfct = &ct->ct_general; 743 skb->nfctinfo = *ctinfo; 744 return ct; 745} 746 747unsigned int 748nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 749 struct sk_buff *skb) 750{ 751 struct nf_conn *ct; 752 enum ip_conntrack_info ctinfo; 753 struct nf_conntrack_l3proto *l3proto; 754 struct nf_conntrack_l4proto *l4proto; 755 unsigned int dataoff; 756 u_int8_t protonum; 757 int set_reply = 0; 758 int ret; 759 760 /* Previously seen (loopback or untracked)? Ignore. */ 761 if (skb->nfct) { 762 NF_CT_STAT_INC_ATOMIC(net, ignore); 763 return NF_ACCEPT; 764 } 765 766 /* rcu_read_lock()ed by nf_hook_slow */ 767 l3proto = __nf_ct_l3proto_find(pf); 768 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 769 &dataoff, &protonum); 770 if (ret <= 0) { 771 pr_debug("not prepared to track yet or error occured\n"); 772 NF_CT_STAT_INC_ATOMIC(net, error); 773 NF_CT_STAT_INC_ATOMIC(net, invalid); 774 return -ret; 775 } 776 777 l4proto = __nf_ct_l4proto_find(pf, protonum); 778 779 /* It may be an special packet, error, unclean... 780 * inverse of the return code tells to the netfilter 781 * core what to do with the packet. */ 782 if (l4proto->error != NULL) { 783 ret = l4proto->error(net, skb, dataoff, &ctinfo, pf, hooknum); 784 if (ret <= 0) { 785 NF_CT_STAT_INC_ATOMIC(net, error); 786 NF_CT_STAT_INC_ATOMIC(net, invalid); 787 return -ret; 788 } 789 } 790 791 ct = resolve_normal_ct(net, skb, dataoff, pf, protonum, 792 l3proto, l4proto, &set_reply, &ctinfo); 793 if (!ct) { 794 /* Not valid part of a connection */ 795 NF_CT_STAT_INC_ATOMIC(net, invalid); 796 return NF_ACCEPT; 797 } 798 799 if (IS_ERR(ct)) { 800 /* Too stressed to deal. */ 801 NF_CT_STAT_INC_ATOMIC(net, drop); 802 return NF_DROP; 803 } 804 805 NF_CT_ASSERT(skb->nfct); 806 807 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum); 808 if (ret <= 0) { 809 /* Invalid: inverse of the return code tells 810 * the netfilter core what to do */ 811 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 812 nf_conntrack_put(skb->nfct); 813 skb->nfct = NULL; 814 NF_CT_STAT_INC_ATOMIC(net, invalid); 815 if (ret == -NF_DROP) 816 NF_CT_STAT_INC_ATOMIC(net, drop); 817 return -ret; 818 } 819 820 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 821 nf_conntrack_event_cache(IPCT_STATUS, ct); 822 823 return ret; 824} 825EXPORT_SYMBOL_GPL(nf_conntrack_in); 826 827bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 828 const struct nf_conntrack_tuple *orig) 829{ 830 bool ret; 831 832 rcu_read_lock(); 833 ret = nf_ct_invert_tuple(inverse, orig, 834 __nf_ct_l3proto_find(orig->src.l3num), 835 __nf_ct_l4proto_find(orig->src.l3num, 836 orig->dst.protonum)); 837 rcu_read_unlock(); 838 return ret; 839} 840EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 841 842/* Alter reply tuple (maybe alter helper). This is for NAT, and is 843 implicitly racy: see __nf_conntrack_confirm */ 844void nf_conntrack_alter_reply(struct nf_conn *ct, 845 const struct nf_conntrack_tuple *newreply) 846{ 847 struct nf_conn_help *help = nfct_help(ct); 848 849 /* Should be unconfirmed, so not in hash table yet */ 850 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 851 852 pr_debug("Altering reply tuple of %p to ", ct); 853 nf_ct_dump_tuple(newreply); 854 855 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 856 if (ct->master || (help && !hlist_empty(&help->expectations))) 857 return; 858 859 rcu_read_lock(); 860 __nf_ct_try_assign_helper(ct, GFP_ATOMIC); 861 rcu_read_unlock(); 862} 863EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 864 865/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 866void __nf_ct_refresh_acct(struct nf_conn *ct, 867 enum ip_conntrack_info ctinfo, 868 const struct sk_buff *skb, 869 unsigned long extra_jiffies, 870 int do_acct) 871{ 872 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 873 NF_CT_ASSERT(skb); 874 875 /* Only update if this is not a fixed timeout */ 876 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 877 goto acct; 878 879 /* If not in hash table, timer will not be active yet */ 880 if (!nf_ct_is_confirmed(ct)) { 881 ct->timeout.expires = extra_jiffies; 882 } else { 883 unsigned long newtime = jiffies + extra_jiffies; 884 885 /* Only update the timeout if the new timeout is at least 886 HZ jiffies from the old timeout. Need del_timer for race 887 avoidance (may already be dying). */ 888 if (newtime - ct->timeout.expires >= HZ) 889 mod_timer_pending(&ct->timeout, newtime); 890 } 891 892acct: 893 if (do_acct) { 894 struct nf_conn_counter *acct; 895 896 acct = nf_conn_acct_find(ct); 897 if (acct) { 898 spin_lock_bh(&ct->lock); 899 acct[CTINFO2DIR(ctinfo)].packets++; 900 acct[CTINFO2DIR(ctinfo)].bytes += 901 skb->len - skb_network_offset(skb); 902 spin_unlock_bh(&ct->lock); 903 } 904 } 905} 906EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 907 908bool __nf_ct_kill_acct(struct nf_conn *ct, 909 enum ip_conntrack_info ctinfo, 910 const struct sk_buff *skb, 911 int do_acct) 912{ 913 if (do_acct) { 914 struct nf_conn_counter *acct; 915 916 acct = nf_conn_acct_find(ct); 917 if (acct) { 918 spin_lock_bh(&ct->lock); 919 acct[CTINFO2DIR(ctinfo)].packets++; 920 acct[CTINFO2DIR(ctinfo)].bytes += 921 skb->len - skb_network_offset(skb); 922 spin_unlock_bh(&ct->lock); 923 } 924 } 925 926 if (del_timer(&ct->timeout)) { 927 ct->timeout.function((unsigned long)ct); 928 return true; 929 } 930 return false; 931} 932EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 933 934#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 935 936#include <linux/netfilter/nfnetlink.h> 937#include <linux/netfilter/nfnetlink_conntrack.h> 938#include <linux/mutex.h> 939 940/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 941 * in ip_conntrack_core, since we don't want the protocols to autoload 942 * or depend on ctnetlink */ 943int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 944 const struct nf_conntrack_tuple *tuple) 945{ 946 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port); 947 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port); 948 return 0; 949 950nla_put_failure: 951 return -1; 952} 953EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 954 955const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 956 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 957 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 958}; 959EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 960 961int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 962 struct nf_conntrack_tuple *t) 963{ 964 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 965 return -EINVAL; 966 967 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 968 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 969 970 return 0; 971} 972EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 973 974int nf_ct_port_nlattr_tuple_size(void) 975{ 976 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 977} 978EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 979#endif 980 981/* Used by ipt_REJECT and ip6t_REJECT. */ 982static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 983{ 984 struct nf_conn *ct; 985 enum ip_conntrack_info ctinfo; 986 987 /* This ICMP is in reverse direction to the packet which caused it */ 988 ct = nf_ct_get(skb, &ctinfo); 989 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 990 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY; 991 else 992 ctinfo = IP_CT_RELATED; 993 994 /* Attach to new skbuff, and increment count */ 995 nskb->nfct = &ct->ct_general; 996 nskb->nfctinfo = ctinfo; 997 nf_conntrack_get(nskb->nfct); 998} 999 1000/* Bring out ya dead! */ 1001static struct nf_conn * 1002get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1003 void *data, unsigned int *bucket) 1004{ 1005 struct nf_conntrack_tuple_hash *h; 1006 struct nf_conn *ct; 1007 struct hlist_nulls_node *n; 1008 1009 spin_lock_bh(&nf_conntrack_lock); 1010 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) { 1011 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1012 ct = nf_ct_tuplehash_to_ctrack(h); 1013 if (iter(ct, data)) 1014 goto found; 1015 } 1016 } 1017 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1018 ct = nf_ct_tuplehash_to_ctrack(h); 1019 if (iter(ct, data)) 1020 set_bit(IPS_DYING_BIT, &ct->status); 1021 } 1022 spin_unlock_bh(&nf_conntrack_lock); 1023 return NULL; 1024found: 1025 atomic_inc(&ct->ct_general.use); 1026 spin_unlock_bh(&nf_conntrack_lock); 1027 return ct; 1028} 1029 1030void nf_ct_iterate_cleanup(struct net *net, 1031 int (*iter)(struct nf_conn *i, void *data), 1032 void *data) 1033{ 1034 struct nf_conn *ct; 1035 unsigned int bucket = 0; 1036 1037 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1038 /* Time to push up daises... */ 1039 if (del_timer(&ct->timeout)) 1040 death_by_timeout((unsigned long)ct); 1041 /* ... else the timer will get him soon. */ 1042 1043 nf_ct_put(ct); 1044 } 1045} 1046EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1047 1048struct __nf_ct_flush_report { 1049 u32 pid; 1050 int report; 1051}; 1052 1053static int kill_report(struct nf_conn *i, void *data) 1054{ 1055 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1056 1057 /* If we fail to deliver the event, death_by_timeout() will retry */ 1058 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1059 fr->pid, fr->report) < 0) 1060 return 1; 1061 1062 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1063 set_bit(IPS_DYING_BIT, &i->status); 1064 return 1; 1065} 1066 1067static int kill_all(struct nf_conn *i, void *data) 1068{ 1069 return 1; 1070} 1071 1072void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size) 1073{ 1074 if (vmalloced) 1075 vfree(hash); 1076 else 1077 free_pages((unsigned long)hash, 1078 get_order(sizeof(struct hlist_head) * size)); 1079} 1080EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1081 1082void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1083{ 1084 struct __nf_ct_flush_report fr = { 1085 .pid = pid, 1086 .report = report, 1087 }; 1088 nf_ct_iterate_cleanup(net, kill_report, &fr); 1089} 1090EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1091 1092static void nf_ct_release_dying_list(struct net *net) 1093{ 1094 struct nf_conntrack_tuple_hash *h; 1095 struct nf_conn *ct; 1096 struct hlist_nulls_node *n; 1097 1098 spin_lock_bh(&nf_conntrack_lock); 1099 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1100 ct = nf_ct_tuplehash_to_ctrack(h); 1101 /* never fails to remove them, no listeners at this point */ 1102 nf_ct_kill(ct); 1103 } 1104 spin_unlock_bh(&nf_conntrack_lock); 1105} 1106 1107static void nf_conntrack_cleanup_init_net(void) 1108{ 1109 nf_conntrack_helper_fini(); 1110 nf_conntrack_proto_fini(); 1111 kmem_cache_destroy(nf_conntrack_cachep); 1112} 1113 1114static void nf_conntrack_cleanup_net(struct net *net) 1115{ 1116 i_see_dead_people: 1117 nf_ct_iterate_cleanup(net, kill_all, NULL); 1118 nf_ct_release_dying_list(net); 1119 if (atomic_read(&net->ct.count) != 0) { 1120 schedule(); 1121 goto i_see_dead_people; 1122 } 1123 /* wait until all references to nf_conntrack_untracked are dropped */ 1124 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1) 1125 schedule(); 1126 1127 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1128 nf_conntrack_htable_size); 1129 nf_conntrack_ecache_fini(net); 1130 nf_conntrack_acct_fini(net); 1131 nf_conntrack_expect_fini(net); 1132 free_percpu(net->ct.stat); 1133} 1134 1135/* Mishearing the voices in his head, our hero wonders how he's 1136 supposed to kill the mall. */ 1137void nf_conntrack_cleanup(struct net *net) 1138{ 1139 if (net_eq(net, &init_net)) 1140 rcu_assign_pointer(ip_ct_attach, NULL); 1141 1142 /* This makes sure all current packets have passed through 1143 netfilter framework. Roll on, two-stage module 1144 delete... */ 1145 synchronize_net(); 1146 1147 nf_conntrack_cleanup_net(net); 1148 1149 if (net_eq(net, &init_net)) { 1150 rcu_assign_pointer(nf_ct_destroy, NULL); 1151 nf_conntrack_cleanup_init_net(); 1152 } 1153} 1154 1155void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls) 1156{ 1157 struct hlist_nulls_head *hash; 1158 unsigned int nr_slots, i; 1159 size_t sz; 1160 1161 *vmalloced = 0; 1162 1163 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1164 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1165 sz = nr_slots * sizeof(struct hlist_nulls_head); 1166 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1167 get_order(sz)); 1168 if (!hash) { 1169 *vmalloced = 1; 1170 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1171 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL); 1172 } 1173 1174 if (hash && nulls) 1175 for (i = 0; i < nr_slots; i++) 1176 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1177 1178 return hash; 1179} 1180EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1181 1182int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1183{ 1184 int i, bucket, vmalloced, old_vmalloced; 1185 unsigned int hashsize, old_size; 1186 int rnd; 1187 struct hlist_nulls_head *hash, *old_hash; 1188 struct nf_conntrack_tuple_hash *h; 1189 1190 /* On boot, we can set this without any fancy locking. */ 1191 if (!nf_conntrack_htable_size) 1192 return param_set_uint(val, kp); 1193 1194 hashsize = simple_strtoul(val, NULL, 0); 1195 if (!hashsize) 1196 return -EINVAL; 1197 1198 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1); 1199 if (!hash) 1200 return -ENOMEM; 1201 1202 /* We have to rehahs for the new table anyway, so we also can 1203 * use a newrandom seed */ 1204 get_random_bytes(&rnd, sizeof(rnd)); 1205 1206 /* Lookups in the old hash might happen in parallel, which means we 1207 * might get false negatives during connection lookup. New connections 1208 * created because of a false negative won't make it into the hash 1209 * though since that required taking the lock. 1210 */ 1211 spin_lock_bh(&nf_conntrack_lock); 1212 for (i = 0; i < nf_conntrack_htable_size; i++) { 1213 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1214 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1215 struct nf_conntrack_tuple_hash, hnnode); 1216 hlist_nulls_del_rcu(&h->hnnode); 1217 bucket = __hash_conntrack(&h->tuple, hashsize, rnd); 1218 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1219 } 1220 } 1221 old_size = nf_conntrack_htable_size; 1222 old_vmalloced = init_net.ct.hash_vmalloc; 1223 old_hash = init_net.ct.hash; 1224 1225 nf_conntrack_htable_size = hashsize; 1226 init_net.ct.hash_vmalloc = vmalloced; 1227 init_net.ct.hash = hash; 1228 nf_conntrack_hash_rnd = rnd; 1229 spin_unlock_bh(&nf_conntrack_lock); 1230 1231 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size); 1232 return 0; 1233} 1234EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1235 1236module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1237 &nf_conntrack_htable_size, 0600); 1238 1239static int nf_conntrack_init_init_net(void) 1240{ 1241 int max_factor = 8; 1242 int ret; 1243 1244 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1245 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1246 if (!nf_conntrack_htable_size) { 1247 nf_conntrack_htable_size 1248 = (((totalram_pages << PAGE_SHIFT) / 16384) 1249 / sizeof(struct hlist_head)); 1250 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1251 nf_conntrack_htable_size = 16384; 1252 if (nf_conntrack_htable_size < 32) 1253 nf_conntrack_htable_size = 32; 1254 1255 /* Use a max. factor of four by default to get the same max as 1256 * with the old struct list_heads. When a table size is given 1257 * we use the old value of 8 to avoid reducing the max. 1258 * entries. */ 1259 max_factor = 4; 1260 } 1261 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1262 1263 printk("nf_conntrack version %s (%u buckets, %d max)\n", 1264 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1265 nf_conntrack_max); 1266 1267 nf_conntrack_cachep = kmem_cache_create("nf_conntrack", 1268 sizeof(struct nf_conn), 1269 0, SLAB_DESTROY_BY_RCU, NULL); 1270 if (!nf_conntrack_cachep) { 1271 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1272 ret = -ENOMEM; 1273 goto err_cache; 1274 } 1275 1276 ret = nf_conntrack_proto_init(); 1277 if (ret < 0) 1278 goto err_proto; 1279 1280 ret = nf_conntrack_helper_init(); 1281 if (ret < 0) 1282 goto err_helper; 1283 1284 return 0; 1285 1286err_helper: 1287 nf_conntrack_proto_fini(); 1288err_proto: 1289 kmem_cache_destroy(nf_conntrack_cachep); 1290err_cache: 1291 return ret; 1292} 1293 1294/* 1295 * We need to use special "null" values, not used in hash table 1296 */ 1297#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1298#define DYING_NULLS_VAL ((1<<30)+1) 1299 1300static int nf_conntrack_init_net(struct net *net) 1301{ 1302 int ret; 1303 1304 atomic_set(&net->ct.count, 0); 1305 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1306 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1307 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1308 if (!net->ct.stat) { 1309 ret = -ENOMEM; 1310 goto err_stat; 1311 } 1312 net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1313 &net->ct.hash_vmalloc, 1); 1314 if (!net->ct.hash) { 1315 ret = -ENOMEM; 1316 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1317 goto err_hash; 1318 } 1319 ret = nf_conntrack_expect_init(net); 1320 if (ret < 0) 1321 goto err_expect; 1322 ret = nf_conntrack_acct_init(net); 1323 if (ret < 0) 1324 goto err_acct; 1325 ret = nf_conntrack_ecache_init(net); 1326 if (ret < 0) 1327 goto err_ecache; 1328 1329 /* Set up fake conntrack: 1330 - to never be deleted, not in any hashes */ 1331#ifdef CONFIG_NET_NS 1332 nf_conntrack_untracked.ct_net = &init_net; 1333#endif 1334 atomic_set(&nf_conntrack_untracked.ct_general.use, 1); 1335 /* - and look it like as a confirmed connection */ 1336 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status); 1337 1338 return 0; 1339 1340err_ecache: 1341 nf_conntrack_acct_fini(net); 1342err_acct: 1343 nf_conntrack_expect_fini(net); 1344err_expect: 1345 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1346 nf_conntrack_htable_size); 1347err_hash: 1348 free_percpu(net->ct.stat); 1349err_stat: 1350 return ret; 1351} 1352 1353int nf_conntrack_init(struct net *net) 1354{ 1355 int ret; 1356 1357 if (net_eq(net, &init_net)) { 1358 ret = nf_conntrack_init_init_net(); 1359 if (ret < 0) 1360 goto out_init_net; 1361 } 1362 ret = nf_conntrack_init_net(net); 1363 if (ret < 0) 1364 goto out_net; 1365 1366 if (net_eq(net, &init_net)) { 1367 /* For use by REJECT target */ 1368 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach); 1369 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack); 1370 } 1371 return 0; 1372 1373out_net: 1374 if (net_eq(net, &init_net)) 1375 nf_conntrack_cleanup_init_net(); 1376out_init_net: 1377 return ret; 1378} 1379