nf_conntrack_core.c revision c317428644c0af137d80069ab178cd797da3be45
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/sched.h> 18#include <linux/skbuff.h> 19#include <linux/proc_fs.h> 20#include <linux/vmalloc.h> 21#include <linux/stddef.h> 22#include <linux/slab.h> 23#include <linux/random.h> 24#include <linux/jhash.h> 25#include <linux/err.h> 26#include <linux/percpu.h> 27#include <linux/moduleparam.h> 28#include <linux/notifier.h> 29#include <linux/kernel.h> 30#include <linux/netdevice.h> 31#include <linux/socket.h> 32#include <linux/mm.h> 33#include <linux/nsproxy.h> 34#include <linux/rculist_nulls.h> 35 36#include <net/netfilter/nf_conntrack.h> 37#include <net/netfilter/nf_conntrack_l3proto.h> 38#include <net/netfilter/nf_conntrack_l4proto.h> 39#include <net/netfilter/nf_conntrack_expect.h> 40#include <net/netfilter/nf_conntrack_helper.h> 41#include <net/netfilter/nf_conntrack_core.h> 42#include <net/netfilter/nf_conntrack_extend.h> 43#include <net/netfilter/nf_conntrack_acct.h> 44#include <net/netfilter/nf_conntrack_ecache.h> 45#include <net/netfilter/nf_conntrack_zones.h> 46#include <net/netfilter/nf_nat.h> 47#include <net/netfilter/nf_nat_core.h> 48 49#define NF_CONNTRACK_VERSION "0.5.0" 50 51int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 52 enum nf_nat_manip_type manip, 53 const struct nlattr *attr) __read_mostly; 54EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 55 56DEFINE_SPINLOCK(nf_conntrack_lock); 57EXPORT_SYMBOL_GPL(nf_conntrack_lock); 58 59unsigned int nf_conntrack_htable_size __read_mostly; 60EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 61 62unsigned int nf_conntrack_max __read_mostly; 63EXPORT_SYMBOL_GPL(nf_conntrack_max); 64 65DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 66EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 67 68unsigned int nf_conntrack_hash_rnd __read_mostly; 69 70static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 71{ 72 unsigned int n; 73 74 /* The direction must be ignored, so we hash everything up to the 75 * destination ports (which is a multiple of 4) and treat the last 76 * three bytes manually. 77 */ 78 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 79 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 80 (((__force __u16)tuple->dst.u.all << 16) | 81 tuple->dst.protonum)); 82} 83 84static u32 __hash_bucket(u32 hash, unsigned int size) 85{ 86 return ((u64)hash * size) >> 32; 87} 88 89static u32 hash_bucket(u32 hash, const struct net *net) 90{ 91 return __hash_bucket(hash, net->ct.htable_size); 92} 93 94static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 95 u16 zone, unsigned int size) 96{ 97 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 98} 99 100static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 101 const struct nf_conntrack_tuple *tuple) 102{ 103 return __hash_conntrack(tuple, zone, net->ct.htable_size); 104} 105 106bool 107nf_ct_get_tuple(const struct sk_buff *skb, 108 unsigned int nhoff, 109 unsigned int dataoff, 110 u_int16_t l3num, 111 u_int8_t protonum, 112 struct nf_conntrack_tuple *tuple, 113 const struct nf_conntrack_l3proto *l3proto, 114 const struct nf_conntrack_l4proto *l4proto) 115{ 116 memset(tuple, 0, sizeof(*tuple)); 117 118 tuple->src.l3num = l3num; 119 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 120 return false; 121 122 tuple->dst.protonum = protonum; 123 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 124 125 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 126} 127EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 128 129bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 130 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 131{ 132 struct nf_conntrack_l3proto *l3proto; 133 struct nf_conntrack_l4proto *l4proto; 134 unsigned int protoff; 135 u_int8_t protonum; 136 int ret; 137 138 rcu_read_lock(); 139 140 l3proto = __nf_ct_l3proto_find(l3num); 141 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 142 if (ret != NF_ACCEPT) { 143 rcu_read_unlock(); 144 return false; 145 } 146 147 l4proto = __nf_ct_l4proto_find(l3num, protonum); 148 149 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 150 l3proto, l4proto); 151 152 rcu_read_unlock(); 153 return ret; 154} 155EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 156 157bool 158nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 159 const struct nf_conntrack_tuple *orig, 160 const struct nf_conntrack_l3proto *l3proto, 161 const struct nf_conntrack_l4proto *l4proto) 162{ 163 memset(inverse, 0, sizeof(*inverse)); 164 165 inverse->src.l3num = orig->src.l3num; 166 if (l3proto->invert_tuple(inverse, orig) == 0) 167 return false; 168 169 inverse->dst.dir = !orig->dst.dir; 170 171 inverse->dst.protonum = orig->dst.protonum; 172 return l4proto->invert_tuple(inverse, orig); 173} 174EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 175 176static void 177clean_from_lists(struct nf_conn *ct) 178{ 179 pr_debug("clean_from_lists(%p)\n", ct); 180 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 181 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 182 183 /* Destroy all pending expectations */ 184 nf_ct_remove_expectations(ct); 185} 186 187static void 188destroy_conntrack(struct nf_conntrack *nfct) 189{ 190 struct nf_conn *ct = (struct nf_conn *)nfct; 191 struct net *net = nf_ct_net(ct); 192 struct nf_conntrack_l4proto *l4proto; 193 194 pr_debug("destroy_conntrack(%p)\n", ct); 195 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 196 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 197 198 /* To make sure we don't get any weird locking issues here: 199 * destroy_conntrack() MUST NOT be called with a write lock 200 * to nf_conntrack_lock!!! -HW */ 201 rcu_read_lock(); 202 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 203 if (l4proto && l4proto->destroy) 204 l4proto->destroy(ct); 205 206 rcu_read_unlock(); 207 208 spin_lock_bh(&nf_conntrack_lock); 209 /* Expectations will have been removed in clean_from_lists, 210 * except TFTP can create an expectation on the first packet, 211 * before connection is in the list, so we need to clean here, 212 * too. */ 213 nf_ct_remove_expectations(ct); 214 215 /* We overload first tuple to link into unconfirmed list. */ 216 if (!nf_ct_is_confirmed(ct)) { 217 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 218 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 219 } 220 221 NF_CT_STAT_INC(net, delete); 222 spin_unlock_bh(&nf_conntrack_lock); 223 224 if (ct->master) 225 nf_ct_put(ct->master); 226 227 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 228 nf_conntrack_free(ct); 229} 230 231void nf_ct_delete_from_lists(struct nf_conn *ct) 232{ 233 struct net *net = nf_ct_net(ct); 234 235 nf_ct_helper_destroy(ct); 236 spin_lock_bh(&nf_conntrack_lock); 237 /* Inside lock so preempt is disabled on module removal path. 238 * Otherwise we can get spurious warnings. */ 239 NF_CT_STAT_INC(net, delete_list); 240 clean_from_lists(ct); 241 spin_unlock_bh(&nf_conntrack_lock); 242} 243EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 244 245static void death_by_event(unsigned long ul_conntrack) 246{ 247 struct nf_conn *ct = (void *)ul_conntrack; 248 struct net *net = nf_ct_net(ct); 249 250 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 251 /* bad luck, let's retry again */ 252 ct->timeout.expires = jiffies + 253 (random32() % net->ct.sysctl_events_retry_timeout); 254 add_timer(&ct->timeout); 255 return; 256 } 257 /* we've got the event delivered, now it's dying */ 258 set_bit(IPS_DYING_BIT, &ct->status); 259 spin_lock(&nf_conntrack_lock); 260 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 261 spin_unlock(&nf_conntrack_lock); 262 nf_ct_put(ct); 263} 264 265void nf_ct_insert_dying_list(struct nf_conn *ct) 266{ 267 struct net *net = nf_ct_net(ct); 268 269 /* add this conntrack to the dying list */ 270 spin_lock_bh(&nf_conntrack_lock); 271 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 272 &net->ct.dying); 273 spin_unlock_bh(&nf_conntrack_lock); 274 /* set a new timer to retry event delivery */ 275 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); 276 ct->timeout.expires = jiffies + 277 (random32() % net->ct.sysctl_events_retry_timeout); 278 add_timer(&ct->timeout); 279} 280EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); 281 282static void death_by_timeout(unsigned long ul_conntrack) 283{ 284 struct nf_conn *ct = (void *)ul_conntrack; 285 286 if (!test_bit(IPS_DYING_BIT, &ct->status) && 287 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 288 /* destroy event was not delivered */ 289 nf_ct_delete_from_lists(ct); 290 nf_ct_insert_dying_list(ct); 291 return; 292 } 293 set_bit(IPS_DYING_BIT, &ct->status); 294 nf_ct_delete_from_lists(ct); 295 nf_ct_put(ct); 296} 297 298/* 299 * Warning : 300 * - Caller must take a reference on returned object 301 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 302 * OR 303 * - Caller must lock nf_conntrack_lock before calling this function 304 */ 305static struct nf_conntrack_tuple_hash * 306____nf_conntrack_find(struct net *net, u16 zone, 307 const struct nf_conntrack_tuple *tuple, u32 hash) 308{ 309 struct nf_conntrack_tuple_hash *h; 310 struct hlist_nulls_node *n; 311 unsigned int bucket = hash_bucket(hash, net); 312 313 /* Disable BHs the entire time since we normally need to disable them 314 * at least once for the stats anyway. 315 */ 316 local_bh_disable(); 317begin: 318 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) { 319 if (nf_ct_tuple_equal(tuple, &h->tuple) && 320 nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { 321 NF_CT_STAT_INC(net, found); 322 local_bh_enable(); 323 return h; 324 } 325 NF_CT_STAT_INC(net, searched); 326 } 327 /* 328 * if the nulls value we got at the end of this lookup is 329 * not the expected one, we must restart lookup. 330 * We probably met an item that was moved to another chain. 331 */ 332 if (get_nulls_value(n) != bucket) { 333 NF_CT_STAT_INC(net, search_restart); 334 goto begin; 335 } 336 local_bh_enable(); 337 338 return NULL; 339} 340 341struct nf_conntrack_tuple_hash * 342__nf_conntrack_find(struct net *net, u16 zone, 343 const struct nf_conntrack_tuple *tuple) 344{ 345 return ____nf_conntrack_find(net, zone, tuple, 346 hash_conntrack_raw(tuple, zone)); 347} 348EXPORT_SYMBOL_GPL(__nf_conntrack_find); 349 350/* Find a connection corresponding to a tuple. */ 351static struct nf_conntrack_tuple_hash * 352__nf_conntrack_find_get(struct net *net, u16 zone, 353 const struct nf_conntrack_tuple *tuple, u32 hash) 354{ 355 struct nf_conntrack_tuple_hash *h; 356 struct nf_conn *ct; 357 358 rcu_read_lock(); 359begin: 360 h = ____nf_conntrack_find(net, zone, tuple, hash); 361 if (h) { 362 ct = nf_ct_tuplehash_to_ctrack(h); 363 if (unlikely(nf_ct_is_dying(ct) || 364 !atomic_inc_not_zero(&ct->ct_general.use))) 365 h = NULL; 366 else { 367 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || 368 nf_ct_zone(ct) != zone)) { 369 nf_ct_put(ct); 370 goto begin; 371 } 372 } 373 } 374 rcu_read_unlock(); 375 376 return h; 377} 378 379struct nf_conntrack_tuple_hash * 380nf_conntrack_find_get(struct net *net, u16 zone, 381 const struct nf_conntrack_tuple *tuple) 382{ 383 return __nf_conntrack_find_get(net, zone, tuple, 384 hash_conntrack_raw(tuple, zone)); 385} 386EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 387 388static void __nf_conntrack_hash_insert(struct nf_conn *ct, 389 unsigned int hash, 390 unsigned int repl_hash) 391{ 392 struct net *net = nf_ct_net(ct); 393 394 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 395 &net->ct.hash[hash]); 396 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 397 &net->ct.hash[repl_hash]); 398} 399 400void nf_conntrack_hash_insert(struct nf_conn *ct) 401{ 402 struct net *net = nf_ct_net(ct); 403 unsigned int hash, repl_hash; 404 u16 zone; 405 406 zone = nf_ct_zone(ct); 407 hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 408 repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 409 410 __nf_conntrack_hash_insert(ct, hash, repl_hash); 411} 412EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert); 413 414/* Confirm a connection given skb; places it in hash table */ 415int 416__nf_conntrack_confirm(struct sk_buff *skb) 417{ 418 unsigned int hash, repl_hash; 419 struct nf_conntrack_tuple_hash *h; 420 struct nf_conn *ct; 421 struct nf_conn_help *help; 422 struct hlist_nulls_node *n; 423 enum ip_conntrack_info ctinfo; 424 struct net *net; 425 u16 zone; 426 427 ct = nf_ct_get(skb, &ctinfo); 428 net = nf_ct_net(ct); 429 430 /* ipt_REJECT uses nf_conntrack_attach to attach related 431 ICMP/TCP RST packets in other direction. Actual packet 432 which created connection will be IP_CT_NEW or for an 433 expected connection, IP_CT_RELATED. */ 434 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 435 return NF_ACCEPT; 436 437 zone = nf_ct_zone(ct); 438 /* reuse the hash saved before */ 439 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 440 hash = hash_bucket(hash, net); 441 repl_hash = hash_conntrack(net, zone, 442 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 443 444 /* We're not in hash table, and we refuse to set up related 445 connections for unconfirmed conns. But packet copies and 446 REJECT will give spurious warnings here. */ 447 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 448 449 /* No external references means noone else could have 450 confirmed us. */ 451 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 452 pr_debug("Confirming conntrack %p\n", ct); 453 454 spin_lock_bh(&nf_conntrack_lock); 455 456 /* We have to check the DYING flag inside the lock to prevent 457 a race against nf_ct_get_next_corpse() possibly called from 458 user context, else we insert an already 'dead' hash, blocking 459 further use of that particular connection -JM */ 460 461 if (unlikely(nf_ct_is_dying(ct))) { 462 spin_unlock_bh(&nf_conntrack_lock); 463 return NF_ACCEPT; 464 } 465 466 /* See if there's one in the list already, including reverse: 467 NAT could have grabbed it without realizing, since we're 468 not in the hash. If there is, we lost race. */ 469 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 470 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 471 &h->tuple) && 472 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 473 goto out; 474 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 475 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 476 &h->tuple) && 477 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 478 goto out; 479 480 /* Remove from unconfirmed list */ 481 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 482 483 /* Timer relative to confirmation time, not original 484 setting time, otherwise we'd get timer wrap in 485 weird delay cases. */ 486 ct->timeout.expires += jiffies; 487 add_timer(&ct->timeout); 488 atomic_inc(&ct->ct_general.use); 489 set_bit(IPS_CONFIRMED_BIT, &ct->status); 490 491 /* Since the lookup is lockless, hash insertion must be done after 492 * starting the timer and setting the CONFIRMED bit. The RCU barriers 493 * guarantee that no other CPU can find the conntrack before the above 494 * stores are visible. 495 */ 496 __nf_conntrack_hash_insert(ct, hash, repl_hash); 497 NF_CT_STAT_INC(net, insert); 498 spin_unlock_bh(&nf_conntrack_lock); 499 500 help = nfct_help(ct); 501 if (help && help->helper) 502 nf_conntrack_event_cache(IPCT_HELPER, ct); 503 504 nf_conntrack_event_cache(master_ct(ct) ? 505 IPCT_RELATED : IPCT_NEW, ct); 506 return NF_ACCEPT; 507 508out: 509 NF_CT_STAT_INC(net, insert_failed); 510 spin_unlock_bh(&nf_conntrack_lock); 511 return NF_DROP; 512} 513EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 514 515/* Returns true if a connection correspondings to the tuple (required 516 for NAT). */ 517int 518nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 519 const struct nf_conn *ignored_conntrack) 520{ 521 struct net *net = nf_ct_net(ignored_conntrack); 522 struct nf_conntrack_tuple_hash *h; 523 struct hlist_nulls_node *n; 524 struct nf_conn *ct; 525 u16 zone = nf_ct_zone(ignored_conntrack); 526 unsigned int hash = hash_conntrack(net, zone, tuple); 527 528 /* Disable BHs the entire time since we need to disable them at 529 * least once for the stats anyway. 530 */ 531 rcu_read_lock_bh(); 532 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 533 ct = nf_ct_tuplehash_to_ctrack(h); 534 if (ct != ignored_conntrack && 535 nf_ct_tuple_equal(tuple, &h->tuple) && 536 nf_ct_zone(ct) == zone) { 537 NF_CT_STAT_INC(net, found); 538 rcu_read_unlock_bh(); 539 return 1; 540 } 541 NF_CT_STAT_INC(net, searched); 542 } 543 rcu_read_unlock_bh(); 544 545 return 0; 546} 547EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 548 549#define NF_CT_EVICTION_RANGE 8 550 551/* There's a small race here where we may free a just-assured 552 connection. Too bad: we're in trouble anyway. */ 553static noinline int early_drop(struct net *net, unsigned int hash) 554{ 555 /* Use oldest entry, which is roughly LRU */ 556 struct nf_conntrack_tuple_hash *h; 557 struct nf_conn *ct = NULL, *tmp; 558 struct hlist_nulls_node *n; 559 unsigned int i, cnt = 0; 560 int dropped = 0; 561 562 rcu_read_lock(); 563 for (i = 0; i < net->ct.htable_size; i++) { 564 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 565 hnnode) { 566 tmp = nf_ct_tuplehash_to_ctrack(h); 567 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 568 ct = tmp; 569 cnt++; 570 } 571 572 if (ct != NULL) { 573 if (likely(!nf_ct_is_dying(ct) && 574 atomic_inc_not_zero(&ct->ct_general.use))) 575 break; 576 else 577 ct = NULL; 578 } 579 580 if (cnt >= NF_CT_EVICTION_RANGE) 581 break; 582 583 hash = (hash + 1) % net->ct.htable_size; 584 } 585 rcu_read_unlock(); 586 587 if (!ct) 588 return dropped; 589 590 if (del_timer(&ct->timeout)) { 591 death_by_timeout((unsigned long)ct); 592 dropped = 1; 593 NF_CT_STAT_INC_ATOMIC(net, early_drop); 594 } 595 nf_ct_put(ct); 596 return dropped; 597} 598 599void init_nf_conntrack_hash_rnd(void) 600{ 601 unsigned int rand; 602 603 /* 604 * Why not initialize nf_conntrack_rnd in a "init()" function ? 605 * Because there isn't enough entropy when system initializing, 606 * and we initialize it as late as possible. 607 */ 608 do { 609 get_random_bytes(&rand, sizeof(rand)); 610 } while (!rand); 611 cmpxchg(&nf_conntrack_hash_rnd, 0, rand); 612} 613 614static struct nf_conn * 615__nf_conntrack_alloc(struct net *net, u16 zone, 616 const struct nf_conntrack_tuple *orig, 617 const struct nf_conntrack_tuple *repl, 618 gfp_t gfp, u32 hash) 619{ 620 struct nf_conn *ct; 621 622 if (unlikely(!nf_conntrack_hash_rnd)) { 623 init_nf_conntrack_hash_rnd(); 624 /* recompute the hash as nf_conntrack_hash_rnd is initialized */ 625 hash = hash_conntrack_raw(orig, zone); 626 } 627 628 /* We don't want any race condition at early drop stage */ 629 atomic_inc(&net->ct.count); 630 631 if (nf_conntrack_max && 632 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 633 if (!early_drop(net, hash_bucket(hash, net))) { 634 atomic_dec(&net->ct.count); 635 if (net_ratelimit()) 636 printk(KERN_WARNING 637 "nf_conntrack: table full, dropping" 638 " packet.\n"); 639 return ERR_PTR(-ENOMEM); 640 } 641 } 642 643 /* 644 * Do not use kmem_cache_zalloc(), as this cache uses 645 * SLAB_DESTROY_BY_RCU. 646 */ 647 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 648 if (ct == NULL) { 649 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); 650 atomic_dec(&net->ct.count); 651 return ERR_PTR(-ENOMEM); 652 } 653 /* 654 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 655 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 656 */ 657 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 658 sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 659 spin_lock_init(&ct->lock); 660 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 661 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 662 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 663 /* save hash for reusing when confirming */ 664 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 665 /* Don't set timer yet: wait for confirmation */ 666 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 667 write_pnet(&ct->ct_net, net); 668#ifdef CONFIG_NF_CONNTRACK_ZONES 669 if (zone) { 670 struct nf_conntrack_zone *nf_ct_zone; 671 672 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); 673 if (!nf_ct_zone) 674 goto out_free; 675 nf_ct_zone->id = zone; 676 } 677#endif 678 /* 679 * changes to lookup keys must be done before setting refcnt to 1 680 */ 681 smp_wmb(); 682 atomic_set(&ct->ct_general.use, 1); 683 return ct; 684 685#ifdef CONFIG_NF_CONNTRACK_ZONES 686out_free: 687 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 688 return ERR_PTR(-ENOMEM); 689#endif 690} 691 692struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, 693 const struct nf_conntrack_tuple *orig, 694 const struct nf_conntrack_tuple *repl, 695 gfp_t gfp) 696{ 697 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 698} 699EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 700 701void nf_conntrack_free(struct nf_conn *ct) 702{ 703 struct net *net = nf_ct_net(ct); 704 705 nf_ct_ext_destroy(ct); 706 atomic_dec(&net->ct.count); 707 nf_ct_ext_free(ct); 708 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 709} 710EXPORT_SYMBOL_GPL(nf_conntrack_free); 711 712/* Allocate a new conntrack: we return -ENOMEM if classification 713 failed due to stress. Otherwise it really is unclassifiable. */ 714static struct nf_conntrack_tuple_hash * 715init_conntrack(struct net *net, struct nf_conn *tmpl, 716 const struct nf_conntrack_tuple *tuple, 717 struct nf_conntrack_l3proto *l3proto, 718 struct nf_conntrack_l4proto *l4proto, 719 struct sk_buff *skb, 720 unsigned int dataoff, u32 hash) 721{ 722 struct nf_conn *ct; 723 struct nf_conn_help *help; 724 struct nf_conntrack_tuple repl_tuple; 725 struct nf_conntrack_ecache *ecache; 726 struct nf_conntrack_expect *exp; 727 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 728 729 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 730 pr_debug("Can't invert tuple.\n"); 731 return NULL; 732 } 733 734 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 735 hash); 736 if (IS_ERR(ct)) { 737 pr_debug("Can't allocate conntrack.\n"); 738 return (struct nf_conntrack_tuple_hash *)ct; 739 } 740 741 if (!l4proto->new(ct, skb, dataoff)) { 742 nf_conntrack_free(ct); 743 pr_debug("init conntrack: can't track with proto module\n"); 744 return NULL; 745 } 746 747 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 748 749 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 750 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 751 ecache ? ecache->expmask : 0, 752 GFP_ATOMIC); 753 754 spin_lock_bh(&nf_conntrack_lock); 755 exp = nf_ct_find_expectation(net, zone, tuple); 756 if (exp) { 757 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 758 ct, exp); 759 /* Welcome, Mr. Bond. We've been expecting you... */ 760 __set_bit(IPS_EXPECTED_BIT, &ct->status); 761 ct->master = exp->master; 762 if (exp->helper) { 763 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 764 if (help) 765 rcu_assign_pointer(help->helper, exp->helper); 766 } 767 768#ifdef CONFIG_NF_CONNTRACK_MARK 769 ct->mark = exp->master->mark; 770#endif 771#ifdef CONFIG_NF_CONNTRACK_SECMARK 772 ct->secmark = exp->master->secmark; 773#endif 774 nf_conntrack_get(&ct->master->ct_general); 775 NF_CT_STAT_INC(net, expect_new); 776 } else { 777 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 778 NF_CT_STAT_INC(net, new); 779 } 780 781 /* Overload tuple linked list to put us in unconfirmed list. */ 782 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 783 &net->ct.unconfirmed); 784 785 spin_unlock_bh(&nf_conntrack_lock); 786 787 if (exp) { 788 if (exp->expectfn) 789 exp->expectfn(ct, exp); 790 nf_ct_expect_put(exp); 791 } 792 793 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 794} 795 796/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 797static inline struct nf_conn * 798resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 799 struct sk_buff *skb, 800 unsigned int dataoff, 801 u_int16_t l3num, 802 u_int8_t protonum, 803 struct nf_conntrack_l3proto *l3proto, 804 struct nf_conntrack_l4proto *l4proto, 805 int *set_reply, 806 enum ip_conntrack_info *ctinfo) 807{ 808 struct nf_conntrack_tuple tuple; 809 struct nf_conntrack_tuple_hash *h; 810 struct nf_conn *ct; 811 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 812 u32 hash; 813 814 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 815 dataoff, l3num, protonum, &tuple, l3proto, 816 l4proto)) { 817 pr_debug("resolve_normal_ct: Can't get tuple\n"); 818 return NULL; 819 } 820 821 /* look for tuple match */ 822 hash = hash_conntrack_raw(&tuple, zone); 823 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 824 if (!h) { 825 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 826 skb, dataoff, hash); 827 if (!h) 828 return NULL; 829 if (IS_ERR(h)) 830 return (void *)h; 831 } 832 ct = nf_ct_tuplehash_to_ctrack(h); 833 834 /* It exists; we have (non-exclusive) reference. */ 835 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 836 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY; 837 /* Please set reply bit if this packet OK */ 838 *set_reply = 1; 839 } else { 840 /* Once we've had two way comms, always ESTABLISHED. */ 841 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 842 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 843 *ctinfo = IP_CT_ESTABLISHED; 844 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 845 pr_debug("nf_conntrack_in: related packet for %p\n", 846 ct); 847 *ctinfo = IP_CT_RELATED; 848 } else { 849 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 850 *ctinfo = IP_CT_NEW; 851 } 852 *set_reply = 0; 853 } 854 skb->nfct = &ct->ct_general; 855 skb->nfctinfo = *ctinfo; 856 return ct; 857} 858 859unsigned int 860nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 861 struct sk_buff *skb) 862{ 863 struct nf_conn *ct, *tmpl = NULL; 864 enum ip_conntrack_info ctinfo; 865 struct nf_conntrack_l3proto *l3proto; 866 struct nf_conntrack_l4proto *l4proto; 867 unsigned int dataoff; 868 u_int8_t protonum; 869 int set_reply = 0; 870 int ret; 871 872 if (skb->nfct) { 873 /* Previously seen (loopback or untracked)? Ignore. */ 874 tmpl = (struct nf_conn *)skb->nfct; 875 if (!nf_ct_is_template(tmpl)) { 876 NF_CT_STAT_INC_ATOMIC(net, ignore); 877 return NF_ACCEPT; 878 } 879 skb->nfct = NULL; 880 } 881 882 /* rcu_read_lock()ed by nf_hook_slow */ 883 l3proto = __nf_ct_l3proto_find(pf); 884 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 885 &dataoff, &protonum); 886 if (ret <= 0) { 887 pr_debug("not prepared to track yet or error occured\n"); 888 NF_CT_STAT_INC_ATOMIC(net, error); 889 NF_CT_STAT_INC_ATOMIC(net, invalid); 890 ret = -ret; 891 goto out; 892 } 893 894 l4proto = __nf_ct_l4proto_find(pf, protonum); 895 896 /* It may be an special packet, error, unclean... 897 * inverse of the return code tells to the netfilter 898 * core what to do with the packet. */ 899 if (l4proto->error != NULL) { 900 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 901 pf, hooknum); 902 if (ret <= 0) { 903 NF_CT_STAT_INC_ATOMIC(net, error); 904 NF_CT_STAT_INC_ATOMIC(net, invalid); 905 ret = -ret; 906 goto out; 907 } 908 } 909 910 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 911 l3proto, l4proto, &set_reply, &ctinfo); 912 if (!ct) { 913 /* Not valid part of a connection */ 914 NF_CT_STAT_INC_ATOMIC(net, invalid); 915 ret = NF_ACCEPT; 916 goto out; 917 } 918 919 if (IS_ERR(ct)) { 920 /* Too stressed to deal. */ 921 NF_CT_STAT_INC_ATOMIC(net, drop); 922 ret = NF_DROP; 923 goto out; 924 } 925 926 NF_CT_ASSERT(skb->nfct); 927 928 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum); 929 if (ret <= 0) { 930 /* Invalid: inverse of the return code tells 931 * the netfilter core what to do */ 932 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 933 nf_conntrack_put(skb->nfct); 934 skb->nfct = NULL; 935 NF_CT_STAT_INC_ATOMIC(net, invalid); 936 if (ret == -NF_DROP) 937 NF_CT_STAT_INC_ATOMIC(net, drop); 938 ret = -ret; 939 goto out; 940 } 941 942 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 943 nf_conntrack_event_cache(IPCT_REPLY, ct); 944out: 945 if (tmpl) { 946 /* Special case: we have to repeat this hook, assign the 947 * template again to this packet. We assume that this packet 948 * has no conntrack assigned. This is used by nf_ct_tcp. */ 949 if (ret == NF_REPEAT) 950 skb->nfct = (struct nf_conntrack *)tmpl; 951 else 952 nf_ct_put(tmpl); 953 } 954 955 return ret; 956} 957EXPORT_SYMBOL_GPL(nf_conntrack_in); 958 959bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 960 const struct nf_conntrack_tuple *orig) 961{ 962 bool ret; 963 964 rcu_read_lock(); 965 ret = nf_ct_invert_tuple(inverse, orig, 966 __nf_ct_l3proto_find(orig->src.l3num), 967 __nf_ct_l4proto_find(orig->src.l3num, 968 orig->dst.protonum)); 969 rcu_read_unlock(); 970 return ret; 971} 972EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 973 974/* Alter reply tuple (maybe alter helper). This is for NAT, and is 975 implicitly racy: see __nf_conntrack_confirm */ 976void nf_conntrack_alter_reply(struct nf_conn *ct, 977 const struct nf_conntrack_tuple *newreply) 978{ 979 struct nf_conn_help *help = nfct_help(ct); 980 981 /* Should be unconfirmed, so not in hash table yet */ 982 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 983 984 pr_debug("Altering reply tuple of %p to ", ct); 985 nf_ct_dump_tuple(newreply); 986 987 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 988 if (ct->master || (help && !hlist_empty(&help->expectations))) 989 return; 990 991 rcu_read_lock(); 992 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 993 rcu_read_unlock(); 994} 995EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 996 997/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 998void __nf_ct_refresh_acct(struct nf_conn *ct, 999 enum ip_conntrack_info ctinfo, 1000 const struct sk_buff *skb, 1001 unsigned long extra_jiffies, 1002 int do_acct) 1003{ 1004 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 1005 NF_CT_ASSERT(skb); 1006 1007 /* Only update if this is not a fixed timeout */ 1008 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 1009 goto acct; 1010 1011 /* If not in hash table, timer will not be active yet */ 1012 if (!nf_ct_is_confirmed(ct)) { 1013 ct->timeout.expires = extra_jiffies; 1014 } else { 1015 unsigned long newtime = jiffies + extra_jiffies; 1016 1017 /* Only update the timeout if the new timeout is at least 1018 HZ jiffies from the old timeout. Need del_timer for race 1019 avoidance (may already be dying). */ 1020 if (newtime - ct->timeout.expires >= HZ) 1021 mod_timer_pending(&ct->timeout, newtime); 1022 } 1023 1024acct: 1025 if (do_acct) { 1026 struct nf_conn_counter *acct; 1027 1028 acct = nf_conn_acct_find(ct); 1029 if (acct) { 1030 spin_lock_bh(&ct->lock); 1031 acct[CTINFO2DIR(ctinfo)].packets++; 1032 acct[CTINFO2DIR(ctinfo)].bytes += skb->len; 1033 spin_unlock_bh(&ct->lock); 1034 } 1035 } 1036} 1037EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1038 1039bool __nf_ct_kill_acct(struct nf_conn *ct, 1040 enum ip_conntrack_info ctinfo, 1041 const struct sk_buff *skb, 1042 int do_acct) 1043{ 1044 if (do_acct) { 1045 struct nf_conn_counter *acct; 1046 1047 acct = nf_conn_acct_find(ct); 1048 if (acct) { 1049 spin_lock_bh(&ct->lock); 1050 acct[CTINFO2DIR(ctinfo)].packets++; 1051 acct[CTINFO2DIR(ctinfo)].bytes += 1052 skb->len - skb_network_offset(skb); 1053 spin_unlock_bh(&ct->lock); 1054 } 1055 } 1056 1057 if (del_timer(&ct->timeout)) { 1058 ct->timeout.function((unsigned long)ct); 1059 return true; 1060 } 1061 return false; 1062} 1063EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1064 1065#ifdef CONFIG_NF_CONNTRACK_ZONES 1066static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1067 .len = sizeof(struct nf_conntrack_zone), 1068 .align = __alignof__(struct nf_conntrack_zone), 1069 .id = NF_CT_EXT_ZONE, 1070}; 1071#endif 1072 1073#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 1074 1075#include <linux/netfilter/nfnetlink.h> 1076#include <linux/netfilter/nfnetlink_conntrack.h> 1077#include <linux/mutex.h> 1078 1079/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1080 * in ip_conntrack_core, since we don't want the protocols to autoload 1081 * or depend on ctnetlink */ 1082int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1083 const struct nf_conntrack_tuple *tuple) 1084{ 1085 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port); 1086 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port); 1087 return 0; 1088 1089nla_put_failure: 1090 return -1; 1091} 1092EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1093 1094const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1095 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1096 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1097}; 1098EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1099 1100int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1101 struct nf_conntrack_tuple *t) 1102{ 1103 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1104 return -EINVAL; 1105 1106 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1107 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1108 1109 return 0; 1110} 1111EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1112 1113int nf_ct_port_nlattr_tuple_size(void) 1114{ 1115 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1116} 1117EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1118#endif 1119 1120/* Used by ipt_REJECT and ip6t_REJECT. */ 1121static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1122{ 1123 struct nf_conn *ct; 1124 enum ip_conntrack_info ctinfo; 1125 1126 /* This ICMP is in reverse direction to the packet which caused it */ 1127 ct = nf_ct_get(skb, &ctinfo); 1128 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1129 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY; 1130 else 1131 ctinfo = IP_CT_RELATED; 1132 1133 /* Attach to new skbuff, and increment count */ 1134 nskb->nfct = &ct->ct_general; 1135 nskb->nfctinfo = ctinfo; 1136 nf_conntrack_get(nskb->nfct); 1137} 1138 1139/* Bring out ya dead! */ 1140static struct nf_conn * 1141get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1142 void *data, unsigned int *bucket) 1143{ 1144 struct nf_conntrack_tuple_hash *h; 1145 struct nf_conn *ct; 1146 struct hlist_nulls_node *n; 1147 1148 spin_lock_bh(&nf_conntrack_lock); 1149 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1150 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1151 ct = nf_ct_tuplehash_to_ctrack(h); 1152 if (iter(ct, data)) 1153 goto found; 1154 } 1155 } 1156 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1157 ct = nf_ct_tuplehash_to_ctrack(h); 1158 if (iter(ct, data)) 1159 set_bit(IPS_DYING_BIT, &ct->status); 1160 } 1161 spin_unlock_bh(&nf_conntrack_lock); 1162 return NULL; 1163found: 1164 atomic_inc(&ct->ct_general.use); 1165 spin_unlock_bh(&nf_conntrack_lock); 1166 return ct; 1167} 1168 1169void nf_ct_iterate_cleanup(struct net *net, 1170 int (*iter)(struct nf_conn *i, void *data), 1171 void *data) 1172{ 1173 struct nf_conn *ct; 1174 unsigned int bucket = 0; 1175 1176 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1177 /* Time to push up daises... */ 1178 if (del_timer(&ct->timeout)) 1179 death_by_timeout((unsigned long)ct); 1180 /* ... else the timer will get him soon. */ 1181 1182 nf_ct_put(ct); 1183 } 1184} 1185EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1186 1187struct __nf_ct_flush_report { 1188 u32 pid; 1189 int report; 1190}; 1191 1192static int kill_report(struct nf_conn *i, void *data) 1193{ 1194 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1195 1196 /* If we fail to deliver the event, death_by_timeout() will retry */ 1197 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1198 fr->pid, fr->report) < 0) 1199 return 1; 1200 1201 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1202 set_bit(IPS_DYING_BIT, &i->status); 1203 return 1; 1204} 1205 1206static int kill_all(struct nf_conn *i, void *data) 1207{ 1208 return 1; 1209} 1210 1211void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size) 1212{ 1213 if (vmalloced) 1214 vfree(hash); 1215 else 1216 free_pages((unsigned long)hash, 1217 get_order(sizeof(struct hlist_head) * size)); 1218} 1219EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1220 1221void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1222{ 1223 struct __nf_ct_flush_report fr = { 1224 .pid = pid, 1225 .report = report, 1226 }; 1227 nf_ct_iterate_cleanup(net, kill_report, &fr); 1228} 1229EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1230 1231static void nf_ct_release_dying_list(struct net *net) 1232{ 1233 struct nf_conntrack_tuple_hash *h; 1234 struct nf_conn *ct; 1235 struct hlist_nulls_node *n; 1236 1237 spin_lock_bh(&nf_conntrack_lock); 1238 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1239 ct = nf_ct_tuplehash_to_ctrack(h); 1240 /* never fails to remove them, no listeners at this point */ 1241 nf_ct_kill(ct); 1242 } 1243 spin_unlock_bh(&nf_conntrack_lock); 1244} 1245 1246static int untrack_refs(void) 1247{ 1248 int cnt = 0, cpu; 1249 1250 for_each_possible_cpu(cpu) { 1251 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1252 1253 cnt += atomic_read(&ct->ct_general.use) - 1; 1254 } 1255 return cnt; 1256} 1257 1258static void nf_conntrack_cleanup_init_net(void) 1259{ 1260 while (untrack_refs() > 0) 1261 schedule(); 1262 1263 nf_conntrack_helper_fini(); 1264 nf_conntrack_proto_fini(); 1265#ifdef CONFIG_NF_CONNTRACK_ZONES 1266 nf_ct_extend_unregister(&nf_ct_zone_extend); 1267#endif 1268} 1269 1270static void nf_conntrack_cleanup_net(struct net *net) 1271{ 1272 i_see_dead_people: 1273 nf_ct_iterate_cleanup(net, kill_all, NULL); 1274 nf_ct_release_dying_list(net); 1275 if (atomic_read(&net->ct.count) != 0) { 1276 schedule(); 1277 goto i_see_dead_people; 1278 } 1279 1280 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1281 net->ct.htable_size); 1282 nf_conntrack_ecache_fini(net); 1283 nf_conntrack_acct_fini(net); 1284 nf_conntrack_expect_fini(net); 1285 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1286 kfree(net->ct.slabname); 1287 free_percpu(net->ct.stat); 1288} 1289 1290/* Mishearing the voices in his head, our hero wonders how he's 1291 supposed to kill the mall. */ 1292void nf_conntrack_cleanup(struct net *net) 1293{ 1294 if (net_eq(net, &init_net)) 1295 rcu_assign_pointer(ip_ct_attach, NULL); 1296 1297 /* This makes sure all current packets have passed through 1298 netfilter framework. Roll on, two-stage module 1299 delete... */ 1300 synchronize_net(); 1301 1302 nf_conntrack_cleanup_net(net); 1303 1304 if (net_eq(net, &init_net)) { 1305 rcu_assign_pointer(nf_ct_destroy, NULL); 1306 nf_conntrack_cleanup_init_net(); 1307 } 1308} 1309 1310void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls) 1311{ 1312 struct hlist_nulls_head *hash; 1313 unsigned int nr_slots, i; 1314 size_t sz; 1315 1316 *vmalloced = 0; 1317 1318 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1319 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1320 sz = nr_slots * sizeof(struct hlist_nulls_head); 1321 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1322 get_order(sz)); 1323 if (!hash) { 1324 *vmalloced = 1; 1325 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1326 hash = __vmalloc(sz, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, 1327 PAGE_KERNEL); 1328 } 1329 1330 if (hash && nulls) 1331 for (i = 0; i < nr_slots; i++) 1332 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1333 1334 return hash; 1335} 1336EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1337 1338int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1339{ 1340 int i, bucket, vmalloced, old_vmalloced; 1341 unsigned int hashsize, old_size; 1342 struct hlist_nulls_head *hash, *old_hash; 1343 struct nf_conntrack_tuple_hash *h; 1344 struct nf_conn *ct; 1345 1346 if (current->nsproxy->net_ns != &init_net) 1347 return -EOPNOTSUPP; 1348 1349 /* On boot, we can set this without any fancy locking. */ 1350 if (!nf_conntrack_htable_size) 1351 return param_set_uint(val, kp); 1352 1353 hashsize = simple_strtoul(val, NULL, 0); 1354 if (!hashsize) 1355 return -EINVAL; 1356 1357 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1); 1358 if (!hash) 1359 return -ENOMEM; 1360 1361 /* Lookups in the old hash might happen in parallel, which means we 1362 * might get false negatives during connection lookup. New connections 1363 * created because of a false negative won't make it into the hash 1364 * though since that required taking the lock. 1365 */ 1366 spin_lock_bh(&nf_conntrack_lock); 1367 for (i = 0; i < init_net.ct.htable_size; i++) { 1368 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1369 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1370 struct nf_conntrack_tuple_hash, hnnode); 1371 ct = nf_ct_tuplehash_to_ctrack(h); 1372 hlist_nulls_del_rcu(&h->hnnode); 1373 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1374 hashsize); 1375 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1376 } 1377 } 1378 old_size = init_net.ct.htable_size; 1379 old_vmalloced = init_net.ct.hash_vmalloc; 1380 old_hash = init_net.ct.hash; 1381 1382 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1383 init_net.ct.hash_vmalloc = vmalloced; 1384 init_net.ct.hash = hash; 1385 spin_unlock_bh(&nf_conntrack_lock); 1386 1387 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size); 1388 return 0; 1389} 1390EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1391 1392module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1393 &nf_conntrack_htable_size, 0600); 1394 1395void nf_ct_untracked_status_or(unsigned long bits) 1396{ 1397 int cpu; 1398 1399 for_each_possible_cpu(cpu) 1400 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1401} 1402EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1403 1404static int nf_conntrack_init_init_net(void) 1405{ 1406 int max_factor = 8; 1407 int ret, cpu; 1408 1409 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1410 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1411 if (!nf_conntrack_htable_size) { 1412 nf_conntrack_htable_size 1413 = (((totalram_pages << PAGE_SHIFT) / 16384) 1414 / sizeof(struct hlist_head)); 1415 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1416 nf_conntrack_htable_size = 16384; 1417 if (nf_conntrack_htable_size < 32) 1418 nf_conntrack_htable_size = 32; 1419 1420 /* Use a max. factor of four by default to get the same max as 1421 * with the old struct list_heads. When a table size is given 1422 * we use the old value of 8 to avoid reducing the max. 1423 * entries. */ 1424 max_factor = 4; 1425 } 1426 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1427 1428 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1429 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1430 nf_conntrack_max); 1431 1432 ret = nf_conntrack_proto_init(); 1433 if (ret < 0) 1434 goto err_proto; 1435 1436 ret = nf_conntrack_helper_init(); 1437 if (ret < 0) 1438 goto err_helper; 1439 1440#ifdef CONFIG_NF_CONNTRACK_ZONES 1441 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1442 if (ret < 0) 1443 goto err_extend; 1444#endif 1445 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1446 for_each_possible_cpu(cpu) { 1447 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1448 write_pnet(&ct->ct_net, &init_net); 1449 atomic_set(&ct->ct_general.use, 1); 1450 } 1451 /* - and look it like as a confirmed connection */ 1452 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1453 return 0; 1454 1455#ifdef CONFIG_NF_CONNTRACK_ZONES 1456err_extend: 1457 nf_conntrack_helper_fini(); 1458#endif 1459err_helper: 1460 nf_conntrack_proto_fini(); 1461err_proto: 1462 return ret; 1463} 1464 1465/* 1466 * We need to use special "null" values, not used in hash table 1467 */ 1468#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1469#define DYING_NULLS_VAL ((1<<30)+1) 1470 1471static int nf_conntrack_init_net(struct net *net) 1472{ 1473 int ret; 1474 1475 atomic_set(&net->ct.count, 0); 1476 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1477 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1478 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1479 if (!net->ct.stat) { 1480 ret = -ENOMEM; 1481 goto err_stat; 1482 } 1483 1484 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1485 if (!net->ct.slabname) { 1486 ret = -ENOMEM; 1487 goto err_slabname; 1488 } 1489 1490 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1491 sizeof(struct nf_conn), 0, 1492 SLAB_DESTROY_BY_RCU, NULL); 1493 if (!net->ct.nf_conntrack_cachep) { 1494 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1495 ret = -ENOMEM; 1496 goto err_cache; 1497 } 1498 1499 net->ct.htable_size = nf_conntrack_htable_size; 1500 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1501 &net->ct.hash_vmalloc, 1); 1502 if (!net->ct.hash) { 1503 ret = -ENOMEM; 1504 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1505 goto err_hash; 1506 } 1507 ret = nf_conntrack_expect_init(net); 1508 if (ret < 0) 1509 goto err_expect; 1510 ret = nf_conntrack_acct_init(net); 1511 if (ret < 0) 1512 goto err_acct; 1513 ret = nf_conntrack_ecache_init(net); 1514 if (ret < 0) 1515 goto err_ecache; 1516 1517 return 0; 1518 1519err_ecache: 1520 nf_conntrack_acct_fini(net); 1521err_acct: 1522 nf_conntrack_expect_fini(net); 1523err_expect: 1524 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1525 net->ct.htable_size); 1526err_hash: 1527 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1528err_cache: 1529 kfree(net->ct.slabname); 1530err_slabname: 1531 free_percpu(net->ct.stat); 1532err_stat: 1533 return ret; 1534} 1535 1536s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1537 enum ip_conntrack_dir dir, 1538 u32 seq); 1539EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1540 1541int nf_conntrack_init(struct net *net) 1542{ 1543 int ret; 1544 1545 if (net_eq(net, &init_net)) { 1546 ret = nf_conntrack_init_init_net(); 1547 if (ret < 0) 1548 goto out_init_net; 1549 } 1550 ret = nf_conntrack_init_net(net); 1551 if (ret < 0) 1552 goto out_net; 1553 1554 if (net_eq(net, &init_net)) { 1555 /* For use by REJECT target */ 1556 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach); 1557 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack); 1558 1559 /* Howto get NAT offsets */ 1560 rcu_assign_pointer(nf_ct_nat_offset, NULL); 1561 } 1562 return 0; 1563 1564out_net: 1565 if (net_eq(net, &init_net)) 1566 nf_conntrack_cleanup_init_net(); 1567out_init_net: 1568 return ret; 1569} 1570