nf_conntrack_core.c revision b3e0bfa71b1db9d7a9fbea6965867784fd00ca3c
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_conntrack_timestamp.h> 47#include <net/netfilter/nf_nat.h> 48#include <net/netfilter/nf_nat_core.h> 49 50#define NF_CONNTRACK_VERSION "0.5.0" 51 52int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 53 enum nf_nat_manip_type manip, 54 const struct nlattr *attr) __read_mostly; 55EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 56 57DEFINE_SPINLOCK(nf_conntrack_lock); 58EXPORT_SYMBOL_GPL(nf_conntrack_lock); 59 60unsigned int nf_conntrack_htable_size __read_mostly; 61EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 62 63unsigned int nf_conntrack_max __read_mostly; 64EXPORT_SYMBOL_GPL(nf_conntrack_max); 65 66DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 67EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 68 69unsigned int nf_conntrack_hash_rnd __read_mostly; 70 71static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 72{ 73 unsigned int n; 74 75 /* The direction must be ignored, so we hash everything up to the 76 * destination ports (which is a multiple of 4) and treat the last 77 * three bytes manually. 78 */ 79 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 80 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 81 (((__force __u16)tuple->dst.u.all << 16) | 82 tuple->dst.protonum)); 83} 84 85static u32 __hash_bucket(u32 hash, unsigned int size) 86{ 87 return ((u64)hash * size) >> 32; 88} 89 90static u32 hash_bucket(u32 hash, const struct net *net) 91{ 92 return __hash_bucket(hash, net->ct.htable_size); 93} 94 95static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 96 u16 zone, unsigned int size) 97{ 98 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 99} 100 101static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 102 const struct nf_conntrack_tuple *tuple) 103{ 104 return __hash_conntrack(tuple, zone, net->ct.htable_size); 105} 106 107bool 108nf_ct_get_tuple(const struct sk_buff *skb, 109 unsigned int nhoff, 110 unsigned int dataoff, 111 u_int16_t l3num, 112 u_int8_t protonum, 113 struct nf_conntrack_tuple *tuple, 114 const struct nf_conntrack_l3proto *l3proto, 115 const struct nf_conntrack_l4proto *l4proto) 116{ 117 memset(tuple, 0, sizeof(*tuple)); 118 119 tuple->src.l3num = l3num; 120 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 121 return false; 122 123 tuple->dst.protonum = protonum; 124 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 125 126 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 127} 128EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 129 130bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 131 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 132{ 133 struct nf_conntrack_l3proto *l3proto; 134 struct nf_conntrack_l4proto *l4proto; 135 unsigned int protoff; 136 u_int8_t protonum; 137 int ret; 138 139 rcu_read_lock(); 140 141 l3proto = __nf_ct_l3proto_find(l3num); 142 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 143 if (ret != NF_ACCEPT) { 144 rcu_read_unlock(); 145 return false; 146 } 147 148 l4proto = __nf_ct_l4proto_find(l3num, protonum); 149 150 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 151 l3proto, l4proto); 152 153 rcu_read_unlock(); 154 return ret; 155} 156EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 157 158bool 159nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 160 const struct nf_conntrack_tuple *orig, 161 const struct nf_conntrack_l3proto *l3proto, 162 const struct nf_conntrack_l4proto *l4proto) 163{ 164 memset(inverse, 0, sizeof(*inverse)); 165 166 inverse->src.l3num = orig->src.l3num; 167 if (l3proto->invert_tuple(inverse, orig) == 0) 168 return false; 169 170 inverse->dst.dir = !orig->dst.dir; 171 172 inverse->dst.protonum = orig->dst.protonum; 173 return l4proto->invert_tuple(inverse, orig); 174} 175EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 176 177static void 178clean_from_lists(struct nf_conn *ct) 179{ 180 pr_debug("clean_from_lists(%p)\n", ct); 181 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 182 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 183 184 /* Destroy all pending expectations */ 185 nf_ct_remove_expectations(ct); 186} 187 188static void 189destroy_conntrack(struct nf_conntrack *nfct) 190{ 191 struct nf_conn *ct = (struct nf_conn *)nfct; 192 struct net *net = nf_ct_net(ct); 193 struct nf_conntrack_l4proto *l4proto; 194 195 pr_debug("destroy_conntrack(%p)\n", ct); 196 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 197 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 198 199 /* To make sure we don't get any weird locking issues here: 200 * destroy_conntrack() MUST NOT be called with a write lock 201 * to nf_conntrack_lock!!! -HW */ 202 rcu_read_lock(); 203 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 204 if (l4proto && l4proto->destroy) 205 l4proto->destroy(ct); 206 207 rcu_read_unlock(); 208 209 spin_lock_bh(&nf_conntrack_lock); 210 /* Expectations will have been removed in clean_from_lists, 211 * except TFTP can create an expectation on the first packet, 212 * before connection is in the list, so we need to clean here, 213 * too. */ 214 nf_ct_remove_expectations(ct); 215 216 /* We overload first tuple to link into unconfirmed list. */ 217 if (!nf_ct_is_confirmed(ct)) { 218 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 219 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 220 } 221 222 NF_CT_STAT_INC(net, delete); 223 spin_unlock_bh(&nf_conntrack_lock); 224 225 if (ct->master) 226 nf_ct_put(ct->master); 227 228 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 229 nf_conntrack_free(ct); 230} 231 232void nf_ct_delete_from_lists(struct nf_conn *ct) 233{ 234 struct net *net = nf_ct_net(ct); 235 236 nf_ct_helper_destroy(ct); 237 spin_lock_bh(&nf_conntrack_lock); 238 /* Inside lock so preempt is disabled on module removal path. 239 * Otherwise we can get spurious warnings. */ 240 NF_CT_STAT_INC(net, delete_list); 241 clean_from_lists(ct); 242 spin_unlock_bh(&nf_conntrack_lock); 243} 244EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 245 246static void death_by_event(unsigned long ul_conntrack) 247{ 248 struct nf_conn *ct = (void *)ul_conntrack; 249 struct net *net = nf_ct_net(ct); 250 251 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 252 /* bad luck, let's retry again */ 253 ct->timeout.expires = jiffies + 254 (random32() % net->ct.sysctl_events_retry_timeout); 255 add_timer(&ct->timeout); 256 return; 257 } 258 /* we've got the event delivered, now it's dying */ 259 set_bit(IPS_DYING_BIT, &ct->status); 260 spin_lock(&nf_conntrack_lock); 261 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 262 spin_unlock(&nf_conntrack_lock); 263 nf_ct_put(ct); 264} 265 266void nf_ct_insert_dying_list(struct nf_conn *ct) 267{ 268 struct net *net = nf_ct_net(ct); 269 270 /* add this conntrack to the dying list */ 271 spin_lock_bh(&nf_conntrack_lock); 272 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 273 &net->ct.dying); 274 spin_unlock_bh(&nf_conntrack_lock); 275 /* set a new timer to retry event delivery */ 276 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); 277 ct->timeout.expires = jiffies + 278 (random32() % net->ct.sysctl_events_retry_timeout); 279 add_timer(&ct->timeout); 280} 281EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); 282 283static void death_by_timeout(unsigned long ul_conntrack) 284{ 285 struct nf_conn *ct = (void *)ul_conntrack; 286 struct nf_conn_tstamp *tstamp; 287 288 tstamp = nf_conn_tstamp_find(ct); 289 if (tstamp && tstamp->stop == 0) 290 tstamp->stop = ktime_to_ns(ktime_get_real()); 291 292 if (!test_bit(IPS_DYING_BIT, &ct->status) && 293 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 294 /* destroy event was not delivered */ 295 nf_ct_delete_from_lists(ct); 296 nf_ct_insert_dying_list(ct); 297 return; 298 } 299 set_bit(IPS_DYING_BIT, &ct->status); 300 nf_ct_delete_from_lists(ct); 301 nf_ct_put(ct); 302} 303 304/* 305 * Warning : 306 * - Caller must take a reference on returned object 307 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 308 * OR 309 * - Caller must lock nf_conntrack_lock before calling this function 310 */ 311static struct nf_conntrack_tuple_hash * 312____nf_conntrack_find(struct net *net, u16 zone, 313 const struct nf_conntrack_tuple *tuple, u32 hash) 314{ 315 struct nf_conntrack_tuple_hash *h; 316 struct hlist_nulls_node *n; 317 unsigned int bucket = hash_bucket(hash, net); 318 319 /* Disable BHs the entire time since we normally need to disable them 320 * at least once for the stats anyway. 321 */ 322 local_bh_disable(); 323begin: 324 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) { 325 if (nf_ct_tuple_equal(tuple, &h->tuple) && 326 nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { 327 NF_CT_STAT_INC(net, found); 328 local_bh_enable(); 329 return h; 330 } 331 NF_CT_STAT_INC(net, searched); 332 } 333 /* 334 * if the nulls value we got at the end of this lookup is 335 * not the expected one, we must restart lookup. 336 * We probably met an item that was moved to another chain. 337 */ 338 if (get_nulls_value(n) != bucket) { 339 NF_CT_STAT_INC(net, search_restart); 340 goto begin; 341 } 342 local_bh_enable(); 343 344 return NULL; 345} 346 347struct nf_conntrack_tuple_hash * 348__nf_conntrack_find(struct net *net, u16 zone, 349 const struct nf_conntrack_tuple *tuple) 350{ 351 return ____nf_conntrack_find(net, zone, tuple, 352 hash_conntrack_raw(tuple, zone)); 353} 354EXPORT_SYMBOL_GPL(__nf_conntrack_find); 355 356/* Find a connection corresponding to a tuple. */ 357static struct nf_conntrack_tuple_hash * 358__nf_conntrack_find_get(struct net *net, u16 zone, 359 const struct nf_conntrack_tuple *tuple, u32 hash) 360{ 361 struct nf_conntrack_tuple_hash *h; 362 struct nf_conn *ct; 363 364 rcu_read_lock(); 365begin: 366 h = ____nf_conntrack_find(net, zone, tuple, hash); 367 if (h) { 368 ct = nf_ct_tuplehash_to_ctrack(h); 369 if (unlikely(nf_ct_is_dying(ct) || 370 !atomic_inc_not_zero(&ct->ct_general.use))) 371 h = NULL; 372 else { 373 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || 374 nf_ct_zone(ct) != zone)) { 375 nf_ct_put(ct); 376 goto begin; 377 } 378 } 379 } 380 rcu_read_unlock(); 381 382 return h; 383} 384 385struct nf_conntrack_tuple_hash * 386nf_conntrack_find_get(struct net *net, u16 zone, 387 const struct nf_conntrack_tuple *tuple) 388{ 389 return __nf_conntrack_find_get(net, zone, tuple, 390 hash_conntrack_raw(tuple, zone)); 391} 392EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 393 394static void __nf_conntrack_hash_insert(struct nf_conn *ct, 395 unsigned int hash, 396 unsigned int repl_hash) 397{ 398 struct net *net = nf_ct_net(ct); 399 400 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 401 &net->ct.hash[hash]); 402 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 403 &net->ct.hash[repl_hash]); 404} 405 406void nf_conntrack_hash_insert(struct nf_conn *ct) 407{ 408 struct net *net = nf_ct_net(ct); 409 unsigned int hash, repl_hash; 410 u16 zone; 411 412 zone = nf_ct_zone(ct); 413 hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 414 repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 415 416 __nf_conntrack_hash_insert(ct, hash, repl_hash); 417} 418EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert); 419 420/* Confirm a connection given skb; places it in hash table */ 421int 422__nf_conntrack_confirm(struct sk_buff *skb) 423{ 424 unsigned int hash, repl_hash; 425 struct nf_conntrack_tuple_hash *h; 426 struct nf_conn *ct; 427 struct nf_conn_help *help; 428 struct nf_conn_tstamp *tstamp; 429 struct hlist_nulls_node *n; 430 enum ip_conntrack_info ctinfo; 431 struct net *net; 432 u16 zone; 433 434 ct = nf_ct_get(skb, &ctinfo); 435 net = nf_ct_net(ct); 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 zone = nf_ct_zone(ct); 445 /* reuse the hash saved before */ 446 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 447 hash = hash_bucket(hash, net); 448 repl_hash = hash_conntrack(net, zone, 449 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 450 451 /* We're not in hash table, and we refuse to set up related 452 connections for unconfirmed conns. But packet copies and 453 REJECT will give spurious warnings here. */ 454 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 455 456 /* No external references means no one else could have 457 confirmed us. */ 458 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 459 pr_debug("Confirming conntrack %p\n", ct); 460 461 spin_lock_bh(&nf_conntrack_lock); 462 463 /* We have to check the DYING flag inside the lock to prevent 464 a race against nf_ct_get_next_corpse() possibly called from 465 user context, else we insert an already 'dead' hash, blocking 466 further use of that particular connection -JM */ 467 468 if (unlikely(nf_ct_is_dying(ct))) { 469 spin_unlock_bh(&nf_conntrack_lock); 470 return NF_ACCEPT; 471 } 472 473 /* See if there's one in the list already, including reverse: 474 NAT could have grabbed it without realizing, since we're 475 not in the hash. If there is, we lost race. */ 476 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 477 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 478 &h->tuple) && 479 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 480 goto out; 481 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 482 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 483 &h->tuple) && 484 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 485 goto out; 486 487 /* Remove from unconfirmed list */ 488 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 489 490 /* Timer relative to confirmation time, not original 491 setting time, otherwise we'd get timer wrap in 492 weird delay cases. */ 493 ct->timeout.expires += jiffies; 494 add_timer(&ct->timeout); 495 atomic_inc(&ct->ct_general.use); 496 ct->status |= IPS_CONFIRMED; 497 498 /* set conntrack timestamp, if enabled. */ 499 tstamp = nf_conn_tstamp_find(ct); 500 if (tstamp) { 501 if (skb->tstamp.tv64 == 0) 502 __net_timestamp((struct sk_buff *)skb); 503 504 tstamp->start = ktime_to_ns(skb->tstamp); 505 } 506 /* Since the lookup is lockless, hash insertion must be done after 507 * starting the timer and setting the CONFIRMED bit. The RCU barriers 508 * guarantee that no other CPU can find the conntrack before the above 509 * stores are visible. 510 */ 511 __nf_conntrack_hash_insert(ct, hash, repl_hash); 512 NF_CT_STAT_INC(net, insert); 513 spin_unlock_bh(&nf_conntrack_lock); 514 515 help = nfct_help(ct); 516 if (help && help->helper) 517 nf_conntrack_event_cache(IPCT_HELPER, ct); 518 519 nf_conntrack_event_cache(master_ct(ct) ? 520 IPCT_RELATED : IPCT_NEW, ct); 521 return NF_ACCEPT; 522 523out: 524 NF_CT_STAT_INC(net, insert_failed); 525 spin_unlock_bh(&nf_conntrack_lock); 526 return NF_DROP; 527} 528EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 529 530/* Returns true if a connection correspondings to the tuple (required 531 for NAT). */ 532int 533nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 534 const struct nf_conn *ignored_conntrack) 535{ 536 struct net *net = nf_ct_net(ignored_conntrack); 537 struct nf_conntrack_tuple_hash *h; 538 struct hlist_nulls_node *n; 539 struct nf_conn *ct; 540 u16 zone = nf_ct_zone(ignored_conntrack); 541 unsigned int hash = hash_conntrack(net, zone, tuple); 542 543 /* Disable BHs the entire time since we need to disable them at 544 * least once for the stats anyway. 545 */ 546 rcu_read_lock_bh(); 547 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 548 ct = nf_ct_tuplehash_to_ctrack(h); 549 if (ct != ignored_conntrack && 550 nf_ct_tuple_equal(tuple, &h->tuple) && 551 nf_ct_zone(ct) == zone) { 552 NF_CT_STAT_INC(net, found); 553 rcu_read_unlock_bh(); 554 return 1; 555 } 556 NF_CT_STAT_INC(net, searched); 557 } 558 rcu_read_unlock_bh(); 559 560 return 0; 561} 562EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 563 564#define NF_CT_EVICTION_RANGE 8 565 566/* There's a small race here where we may free a just-assured 567 connection. Too bad: we're in trouble anyway. */ 568static noinline int early_drop(struct net *net, unsigned int hash) 569{ 570 /* Use oldest entry, which is roughly LRU */ 571 struct nf_conntrack_tuple_hash *h; 572 struct nf_conn *ct = NULL, *tmp; 573 struct hlist_nulls_node *n; 574 unsigned int i, cnt = 0; 575 int dropped = 0; 576 577 rcu_read_lock(); 578 for (i = 0; i < net->ct.htable_size; i++) { 579 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 580 hnnode) { 581 tmp = nf_ct_tuplehash_to_ctrack(h); 582 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 583 ct = tmp; 584 cnt++; 585 } 586 587 if (ct != NULL) { 588 if (likely(!nf_ct_is_dying(ct) && 589 atomic_inc_not_zero(&ct->ct_general.use))) 590 break; 591 else 592 ct = NULL; 593 } 594 595 if (cnt >= NF_CT_EVICTION_RANGE) 596 break; 597 598 hash = (hash + 1) % net->ct.htable_size; 599 } 600 rcu_read_unlock(); 601 602 if (!ct) 603 return dropped; 604 605 if (del_timer(&ct->timeout)) { 606 death_by_timeout((unsigned long)ct); 607 dropped = 1; 608 NF_CT_STAT_INC_ATOMIC(net, early_drop); 609 } 610 nf_ct_put(ct); 611 return dropped; 612} 613 614void init_nf_conntrack_hash_rnd(void) 615{ 616 unsigned int rand; 617 618 /* 619 * Why not initialize nf_conntrack_rnd in a "init()" function ? 620 * Because there isn't enough entropy when system initializing, 621 * and we initialize it as late as possible. 622 */ 623 do { 624 get_random_bytes(&rand, sizeof(rand)); 625 } while (!rand); 626 cmpxchg(&nf_conntrack_hash_rnd, 0, rand); 627} 628 629static struct nf_conn * 630__nf_conntrack_alloc(struct net *net, u16 zone, 631 const struct nf_conntrack_tuple *orig, 632 const struct nf_conntrack_tuple *repl, 633 gfp_t gfp, u32 hash) 634{ 635 struct nf_conn *ct; 636 637 if (unlikely(!nf_conntrack_hash_rnd)) { 638 init_nf_conntrack_hash_rnd(); 639 /* recompute the hash as nf_conntrack_hash_rnd is initialized */ 640 hash = hash_conntrack_raw(orig, zone); 641 } 642 643 /* We don't want any race condition at early drop stage */ 644 atomic_inc(&net->ct.count); 645 646 if (nf_conntrack_max && 647 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 648 if (!early_drop(net, hash_bucket(hash, net))) { 649 atomic_dec(&net->ct.count); 650 if (net_ratelimit()) 651 printk(KERN_WARNING 652 "nf_conntrack: table full, dropping" 653 " packet.\n"); 654 return ERR_PTR(-ENOMEM); 655 } 656 } 657 658 /* 659 * Do not use kmem_cache_zalloc(), as this cache uses 660 * SLAB_DESTROY_BY_RCU. 661 */ 662 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 663 if (ct == NULL) { 664 atomic_dec(&net->ct.count); 665 return ERR_PTR(-ENOMEM); 666 } 667 /* 668 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 669 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 670 */ 671 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 672 offsetof(struct nf_conn, proto) - 673 offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 674 spin_lock_init(&ct->lock); 675 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 676 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 677 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 678 /* save hash for reusing when confirming */ 679 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 680 /* Don't set timer yet: wait for confirmation */ 681 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 682 write_pnet(&ct->ct_net, net); 683#ifdef CONFIG_NF_CONNTRACK_ZONES 684 if (zone) { 685 struct nf_conntrack_zone *nf_ct_zone; 686 687 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); 688 if (!nf_ct_zone) 689 goto out_free; 690 nf_ct_zone->id = zone; 691 } 692#endif 693 /* 694 * changes to lookup keys must be done before setting refcnt to 1 695 */ 696 smp_wmb(); 697 atomic_set(&ct->ct_general.use, 1); 698 return ct; 699 700#ifdef CONFIG_NF_CONNTRACK_ZONES 701out_free: 702 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 703 return ERR_PTR(-ENOMEM); 704#endif 705} 706 707struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, 708 const struct nf_conntrack_tuple *orig, 709 const struct nf_conntrack_tuple *repl, 710 gfp_t gfp) 711{ 712 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 713} 714EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 715 716void nf_conntrack_free(struct nf_conn *ct) 717{ 718 struct net *net = nf_ct_net(ct); 719 720 nf_ct_ext_destroy(ct); 721 atomic_dec(&net->ct.count); 722 nf_ct_ext_free(ct); 723 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 724} 725EXPORT_SYMBOL_GPL(nf_conntrack_free); 726 727/* Allocate a new conntrack: we return -ENOMEM if classification 728 failed due to stress. Otherwise it really is unclassifiable. */ 729static struct nf_conntrack_tuple_hash * 730init_conntrack(struct net *net, struct nf_conn *tmpl, 731 const struct nf_conntrack_tuple *tuple, 732 struct nf_conntrack_l3proto *l3proto, 733 struct nf_conntrack_l4proto *l4proto, 734 struct sk_buff *skb, 735 unsigned int dataoff, u32 hash) 736{ 737 struct nf_conn *ct; 738 struct nf_conn_help *help; 739 struct nf_conntrack_tuple repl_tuple; 740 struct nf_conntrack_ecache *ecache; 741 struct nf_conntrack_expect *exp; 742 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 743 744 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 745 pr_debug("Can't invert tuple.\n"); 746 return NULL; 747 } 748 749 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 750 hash); 751 if (IS_ERR(ct)) 752 return (struct nf_conntrack_tuple_hash *)ct; 753 754 if (!l4proto->new(ct, skb, dataoff)) { 755 nf_conntrack_free(ct); 756 pr_debug("init conntrack: can't track with proto module\n"); 757 return NULL; 758 } 759 760 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 761 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 762 763 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 764 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 765 ecache ? ecache->expmask : 0, 766 GFP_ATOMIC); 767 768 spin_lock_bh(&nf_conntrack_lock); 769 exp = nf_ct_find_expectation(net, zone, tuple); 770 if (exp) { 771 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 772 ct, exp); 773 /* Welcome, Mr. Bond. We've been expecting you... */ 774 __set_bit(IPS_EXPECTED_BIT, &ct->status); 775 ct->master = exp->master; 776 if (exp->helper) { 777 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 778 if (help) 779 RCU_INIT_POINTER(help->helper, exp->helper); 780 } 781 782#ifdef CONFIG_NF_CONNTRACK_MARK 783 ct->mark = exp->master->mark; 784#endif 785#ifdef CONFIG_NF_CONNTRACK_SECMARK 786 ct->secmark = exp->master->secmark; 787#endif 788 nf_conntrack_get(&ct->master->ct_general); 789 NF_CT_STAT_INC(net, expect_new); 790 } else { 791 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 792 NF_CT_STAT_INC(net, new); 793 } 794 795 /* Overload tuple linked list to put us in unconfirmed list. */ 796 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 797 &net->ct.unconfirmed); 798 799 spin_unlock_bh(&nf_conntrack_lock); 800 801 if (exp) { 802 if (exp->expectfn) 803 exp->expectfn(ct, exp); 804 nf_ct_expect_put(exp); 805 } 806 807 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 808} 809 810/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 811static inline struct nf_conn * 812resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 813 struct sk_buff *skb, 814 unsigned int dataoff, 815 u_int16_t l3num, 816 u_int8_t protonum, 817 struct nf_conntrack_l3proto *l3proto, 818 struct nf_conntrack_l4proto *l4proto, 819 int *set_reply, 820 enum ip_conntrack_info *ctinfo) 821{ 822 struct nf_conntrack_tuple tuple; 823 struct nf_conntrack_tuple_hash *h; 824 struct nf_conn *ct; 825 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 826 u32 hash; 827 828 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 829 dataoff, l3num, protonum, &tuple, l3proto, 830 l4proto)) { 831 pr_debug("resolve_normal_ct: Can't get tuple\n"); 832 return NULL; 833 } 834 835 /* look for tuple match */ 836 hash = hash_conntrack_raw(&tuple, zone); 837 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 838 if (!h) { 839 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 840 skb, dataoff, hash); 841 if (!h) 842 return NULL; 843 if (IS_ERR(h)) 844 return (void *)h; 845 } 846 ct = nf_ct_tuplehash_to_ctrack(h); 847 848 /* It exists; we have (non-exclusive) reference. */ 849 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 850 *ctinfo = IP_CT_ESTABLISHED_REPLY; 851 /* Please set reply bit if this packet OK */ 852 *set_reply = 1; 853 } else { 854 /* Once we've had two way comms, always ESTABLISHED. */ 855 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 856 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 857 *ctinfo = IP_CT_ESTABLISHED; 858 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 859 pr_debug("nf_conntrack_in: related packet for %p\n", 860 ct); 861 *ctinfo = IP_CT_RELATED; 862 } else { 863 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 864 *ctinfo = IP_CT_NEW; 865 } 866 *set_reply = 0; 867 } 868 skb->nfct = &ct->ct_general; 869 skb->nfctinfo = *ctinfo; 870 return ct; 871} 872 873unsigned int 874nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 875 struct sk_buff *skb) 876{ 877 struct nf_conn *ct, *tmpl = NULL; 878 enum ip_conntrack_info ctinfo; 879 struct nf_conntrack_l3proto *l3proto; 880 struct nf_conntrack_l4proto *l4proto; 881 unsigned int dataoff; 882 u_int8_t protonum; 883 int set_reply = 0; 884 int ret; 885 886 if (skb->nfct) { 887 /* Previously seen (loopback or untracked)? Ignore. */ 888 tmpl = (struct nf_conn *)skb->nfct; 889 if (!nf_ct_is_template(tmpl)) { 890 NF_CT_STAT_INC_ATOMIC(net, ignore); 891 return NF_ACCEPT; 892 } 893 skb->nfct = NULL; 894 } 895 896 /* rcu_read_lock()ed by nf_hook_slow */ 897 l3proto = __nf_ct_l3proto_find(pf); 898 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 899 &dataoff, &protonum); 900 if (ret <= 0) { 901 pr_debug("not prepared to track yet or error occurred\n"); 902 NF_CT_STAT_INC_ATOMIC(net, error); 903 NF_CT_STAT_INC_ATOMIC(net, invalid); 904 ret = -ret; 905 goto out; 906 } 907 908 l4proto = __nf_ct_l4proto_find(pf, protonum); 909 910 /* It may be an special packet, error, unclean... 911 * inverse of the return code tells to the netfilter 912 * core what to do with the packet. */ 913 if (l4proto->error != NULL) { 914 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 915 pf, hooknum); 916 if (ret <= 0) { 917 NF_CT_STAT_INC_ATOMIC(net, error); 918 NF_CT_STAT_INC_ATOMIC(net, invalid); 919 ret = -ret; 920 goto out; 921 } 922 /* ICMP[v6] protocol trackers may assign one conntrack. */ 923 if (skb->nfct) 924 goto out; 925 } 926 927 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 928 l3proto, l4proto, &set_reply, &ctinfo); 929 if (!ct) { 930 /* Not valid part of a connection */ 931 NF_CT_STAT_INC_ATOMIC(net, invalid); 932 ret = NF_ACCEPT; 933 goto out; 934 } 935 936 if (IS_ERR(ct)) { 937 /* Too stressed to deal. */ 938 NF_CT_STAT_INC_ATOMIC(net, drop); 939 ret = NF_DROP; 940 goto out; 941 } 942 943 NF_CT_ASSERT(skb->nfct); 944 945 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum); 946 if (ret <= 0) { 947 /* Invalid: inverse of the return code tells 948 * the netfilter core what to do */ 949 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 950 nf_conntrack_put(skb->nfct); 951 skb->nfct = NULL; 952 NF_CT_STAT_INC_ATOMIC(net, invalid); 953 if (ret == -NF_DROP) 954 NF_CT_STAT_INC_ATOMIC(net, drop); 955 ret = -ret; 956 goto out; 957 } 958 959 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 960 nf_conntrack_event_cache(IPCT_REPLY, ct); 961out: 962 if (tmpl) { 963 /* Special case: we have to repeat this hook, assign the 964 * template again to this packet. We assume that this packet 965 * has no conntrack assigned. This is used by nf_ct_tcp. */ 966 if (ret == NF_REPEAT) 967 skb->nfct = (struct nf_conntrack *)tmpl; 968 else 969 nf_ct_put(tmpl); 970 } 971 972 return ret; 973} 974EXPORT_SYMBOL_GPL(nf_conntrack_in); 975 976bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 977 const struct nf_conntrack_tuple *orig) 978{ 979 bool ret; 980 981 rcu_read_lock(); 982 ret = nf_ct_invert_tuple(inverse, orig, 983 __nf_ct_l3proto_find(orig->src.l3num), 984 __nf_ct_l4proto_find(orig->src.l3num, 985 orig->dst.protonum)); 986 rcu_read_unlock(); 987 return ret; 988} 989EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 990 991/* Alter reply tuple (maybe alter helper). This is for NAT, and is 992 implicitly racy: see __nf_conntrack_confirm */ 993void nf_conntrack_alter_reply(struct nf_conn *ct, 994 const struct nf_conntrack_tuple *newreply) 995{ 996 struct nf_conn_help *help = nfct_help(ct); 997 998 /* Should be unconfirmed, so not in hash table yet */ 999 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 1000 1001 pr_debug("Altering reply tuple of %p to ", ct); 1002 nf_ct_dump_tuple(newreply); 1003 1004 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 1005 if (ct->master || (help && !hlist_empty(&help->expectations))) 1006 return; 1007 1008 rcu_read_lock(); 1009 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 1010 rcu_read_unlock(); 1011} 1012EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 1013 1014/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 1015void __nf_ct_refresh_acct(struct nf_conn *ct, 1016 enum ip_conntrack_info ctinfo, 1017 const struct sk_buff *skb, 1018 unsigned long extra_jiffies, 1019 int do_acct) 1020{ 1021 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 1022 NF_CT_ASSERT(skb); 1023 1024 /* Only update if this is not a fixed timeout */ 1025 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 1026 goto acct; 1027 1028 /* If not in hash table, timer will not be active yet */ 1029 if (!nf_ct_is_confirmed(ct)) { 1030 ct->timeout.expires = extra_jiffies; 1031 } else { 1032 unsigned long newtime = jiffies + extra_jiffies; 1033 1034 /* Only update the timeout if the new timeout is at least 1035 HZ jiffies from the old timeout. Need del_timer for race 1036 avoidance (may already be dying). */ 1037 if (newtime - ct->timeout.expires >= HZ) 1038 mod_timer_pending(&ct->timeout, newtime); 1039 } 1040 1041acct: 1042 if (do_acct) { 1043 struct nf_conn_counter *acct; 1044 1045 acct = nf_conn_acct_find(ct); 1046 if (acct) { 1047 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1048 atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes); 1049 } 1050 } 1051} 1052EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1053 1054bool __nf_ct_kill_acct(struct nf_conn *ct, 1055 enum ip_conntrack_info ctinfo, 1056 const struct sk_buff *skb, 1057 int do_acct) 1058{ 1059 if (do_acct) { 1060 struct nf_conn_counter *acct; 1061 1062 acct = nf_conn_acct_find(ct); 1063 if (acct) { 1064 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1065 atomic64_add(skb->len - skb_network_offset(skb), 1066 &acct[CTINFO2DIR(ctinfo)].bytes); 1067 } 1068 } 1069 1070 if (del_timer(&ct->timeout)) { 1071 ct->timeout.function((unsigned long)ct); 1072 return true; 1073 } 1074 return false; 1075} 1076EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1077 1078#ifdef CONFIG_NF_CONNTRACK_ZONES 1079static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1080 .len = sizeof(struct nf_conntrack_zone), 1081 .align = __alignof__(struct nf_conntrack_zone), 1082 .id = NF_CT_EXT_ZONE, 1083}; 1084#endif 1085 1086#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 1087 1088#include <linux/netfilter/nfnetlink.h> 1089#include <linux/netfilter/nfnetlink_conntrack.h> 1090#include <linux/mutex.h> 1091 1092/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1093 * in ip_conntrack_core, since we don't want the protocols to autoload 1094 * or depend on ctnetlink */ 1095int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1096 const struct nf_conntrack_tuple *tuple) 1097{ 1098 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port); 1099 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port); 1100 return 0; 1101 1102nla_put_failure: 1103 return -1; 1104} 1105EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1106 1107const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1108 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1109 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1110}; 1111EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1112 1113int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1114 struct nf_conntrack_tuple *t) 1115{ 1116 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1117 return -EINVAL; 1118 1119 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1120 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1121 1122 return 0; 1123} 1124EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1125 1126int nf_ct_port_nlattr_tuple_size(void) 1127{ 1128 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1129} 1130EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1131#endif 1132 1133/* Used by ipt_REJECT and ip6t_REJECT. */ 1134static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1135{ 1136 struct nf_conn *ct; 1137 enum ip_conntrack_info ctinfo; 1138 1139 /* This ICMP is in reverse direction to the packet which caused it */ 1140 ct = nf_ct_get(skb, &ctinfo); 1141 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1142 ctinfo = IP_CT_RELATED_REPLY; 1143 else 1144 ctinfo = IP_CT_RELATED; 1145 1146 /* Attach to new skbuff, and increment count */ 1147 nskb->nfct = &ct->ct_general; 1148 nskb->nfctinfo = ctinfo; 1149 nf_conntrack_get(nskb->nfct); 1150} 1151 1152/* Bring out ya dead! */ 1153static struct nf_conn * 1154get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1155 void *data, unsigned int *bucket) 1156{ 1157 struct nf_conntrack_tuple_hash *h; 1158 struct nf_conn *ct; 1159 struct hlist_nulls_node *n; 1160 1161 spin_lock_bh(&nf_conntrack_lock); 1162 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1163 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1164 ct = nf_ct_tuplehash_to_ctrack(h); 1165 if (iter(ct, data)) 1166 goto found; 1167 } 1168 } 1169 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1170 ct = nf_ct_tuplehash_to_ctrack(h); 1171 if (iter(ct, data)) 1172 set_bit(IPS_DYING_BIT, &ct->status); 1173 } 1174 spin_unlock_bh(&nf_conntrack_lock); 1175 return NULL; 1176found: 1177 atomic_inc(&ct->ct_general.use); 1178 spin_unlock_bh(&nf_conntrack_lock); 1179 return ct; 1180} 1181 1182void nf_ct_iterate_cleanup(struct net *net, 1183 int (*iter)(struct nf_conn *i, void *data), 1184 void *data) 1185{ 1186 struct nf_conn *ct; 1187 unsigned int bucket = 0; 1188 1189 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1190 /* Time to push up daises... */ 1191 if (del_timer(&ct->timeout)) 1192 death_by_timeout((unsigned long)ct); 1193 /* ... else the timer will get him soon. */ 1194 1195 nf_ct_put(ct); 1196 } 1197} 1198EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1199 1200struct __nf_ct_flush_report { 1201 u32 pid; 1202 int report; 1203}; 1204 1205static int kill_report(struct nf_conn *i, void *data) 1206{ 1207 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1208 struct nf_conn_tstamp *tstamp; 1209 1210 tstamp = nf_conn_tstamp_find(i); 1211 if (tstamp && tstamp->stop == 0) 1212 tstamp->stop = ktime_to_ns(ktime_get_real()); 1213 1214 /* If we fail to deliver the event, death_by_timeout() will retry */ 1215 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1216 fr->pid, fr->report) < 0) 1217 return 1; 1218 1219 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1220 set_bit(IPS_DYING_BIT, &i->status); 1221 return 1; 1222} 1223 1224static int kill_all(struct nf_conn *i, void *data) 1225{ 1226 return 1; 1227} 1228 1229void nf_ct_free_hashtable(void *hash, unsigned int size) 1230{ 1231 if (is_vmalloc_addr(hash)) 1232 vfree(hash); 1233 else 1234 free_pages((unsigned long)hash, 1235 get_order(sizeof(struct hlist_head) * size)); 1236} 1237EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1238 1239void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1240{ 1241 struct __nf_ct_flush_report fr = { 1242 .pid = pid, 1243 .report = report, 1244 }; 1245 nf_ct_iterate_cleanup(net, kill_report, &fr); 1246} 1247EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1248 1249static void nf_ct_release_dying_list(struct net *net) 1250{ 1251 struct nf_conntrack_tuple_hash *h; 1252 struct nf_conn *ct; 1253 struct hlist_nulls_node *n; 1254 1255 spin_lock_bh(&nf_conntrack_lock); 1256 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1257 ct = nf_ct_tuplehash_to_ctrack(h); 1258 /* never fails to remove them, no listeners at this point */ 1259 nf_ct_kill(ct); 1260 } 1261 spin_unlock_bh(&nf_conntrack_lock); 1262} 1263 1264static int untrack_refs(void) 1265{ 1266 int cnt = 0, cpu; 1267 1268 for_each_possible_cpu(cpu) { 1269 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1270 1271 cnt += atomic_read(&ct->ct_general.use) - 1; 1272 } 1273 return cnt; 1274} 1275 1276static void nf_conntrack_cleanup_init_net(void) 1277{ 1278 while (untrack_refs() > 0) 1279 schedule(); 1280 1281 nf_conntrack_helper_fini(); 1282 nf_conntrack_proto_fini(); 1283#ifdef CONFIG_NF_CONNTRACK_ZONES 1284 nf_ct_extend_unregister(&nf_ct_zone_extend); 1285#endif 1286} 1287 1288static void nf_conntrack_cleanup_net(struct net *net) 1289{ 1290 i_see_dead_people: 1291 nf_ct_iterate_cleanup(net, kill_all, NULL); 1292 nf_ct_release_dying_list(net); 1293 if (atomic_read(&net->ct.count) != 0) { 1294 schedule(); 1295 goto i_see_dead_people; 1296 } 1297 1298 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1299 nf_conntrack_ecache_fini(net); 1300 nf_conntrack_tstamp_fini(net); 1301 nf_conntrack_acct_fini(net); 1302 nf_conntrack_expect_fini(net); 1303 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1304 kfree(net->ct.slabname); 1305 free_percpu(net->ct.stat); 1306} 1307 1308/* Mishearing the voices in his head, our hero wonders how he's 1309 supposed to kill the mall. */ 1310void nf_conntrack_cleanup(struct net *net) 1311{ 1312 if (net_eq(net, &init_net)) 1313 RCU_INIT_POINTER(ip_ct_attach, NULL); 1314 1315 /* This makes sure all current packets have passed through 1316 netfilter framework. Roll on, two-stage module 1317 delete... */ 1318 synchronize_net(); 1319 1320 nf_conntrack_cleanup_net(net); 1321 1322 if (net_eq(net, &init_net)) { 1323 RCU_INIT_POINTER(nf_ct_destroy, NULL); 1324 nf_conntrack_cleanup_init_net(); 1325 } 1326} 1327 1328void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 1329{ 1330 struct hlist_nulls_head *hash; 1331 unsigned int nr_slots, i; 1332 size_t sz; 1333 1334 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1335 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1336 sz = nr_slots * sizeof(struct hlist_nulls_head); 1337 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1338 get_order(sz)); 1339 if (!hash) { 1340 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1341 hash = __vmalloc(sz, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, 1342 PAGE_KERNEL); 1343 } 1344 1345 if (hash && nulls) 1346 for (i = 0; i < nr_slots; i++) 1347 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1348 1349 return hash; 1350} 1351EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1352 1353int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1354{ 1355 int i, bucket; 1356 unsigned int hashsize, old_size; 1357 struct hlist_nulls_head *hash, *old_hash; 1358 struct nf_conntrack_tuple_hash *h; 1359 struct nf_conn *ct; 1360 1361 if (current->nsproxy->net_ns != &init_net) 1362 return -EOPNOTSUPP; 1363 1364 /* On boot, we can set this without any fancy locking. */ 1365 if (!nf_conntrack_htable_size) 1366 return param_set_uint(val, kp); 1367 1368 hashsize = simple_strtoul(val, NULL, 0); 1369 if (!hashsize) 1370 return -EINVAL; 1371 1372 hash = nf_ct_alloc_hashtable(&hashsize, 1); 1373 if (!hash) 1374 return -ENOMEM; 1375 1376 /* Lookups in the old hash might happen in parallel, which means we 1377 * might get false negatives during connection lookup. New connections 1378 * created because of a false negative won't make it into the hash 1379 * though since that required taking the lock. 1380 */ 1381 spin_lock_bh(&nf_conntrack_lock); 1382 for (i = 0; i < init_net.ct.htable_size; i++) { 1383 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1384 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1385 struct nf_conntrack_tuple_hash, hnnode); 1386 ct = nf_ct_tuplehash_to_ctrack(h); 1387 hlist_nulls_del_rcu(&h->hnnode); 1388 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1389 hashsize); 1390 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1391 } 1392 } 1393 old_size = init_net.ct.htable_size; 1394 old_hash = init_net.ct.hash; 1395 1396 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1397 init_net.ct.hash = hash; 1398 spin_unlock_bh(&nf_conntrack_lock); 1399 1400 nf_ct_free_hashtable(old_hash, old_size); 1401 return 0; 1402} 1403EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1404 1405module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1406 &nf_conntrack_htable_size, 0600); 1407 1408void nf_ct_untracked_status_or(unsigned long bits) 1409{ 1410 int cpu; 1411 1412 for_each_possible_cpu(cpu) 1413 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1414} 1415EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1416 1417static int nf_conntrack_init_init_net(void) 1418{ 1419 int max_factor = 8; 1420 int ret, cpu; 1421 1422 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1423 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1424 if (!nf_conntrack_htable_size) { 1425 nf_conntrack_htable_size 1426 = (((totalram_pages << PAGE_SHIFT) / 16384) 1427 / sizeof(struct hlist_head)); 1428 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1429 nf_conntrack_htable_size = 16384; 1430 if (nf_conntrack_htable_size < 32) 1431 nf_conntrack_htable_size = 32; 1432 1433 /* Use a max. factor of four by default to get the same max as 1434 * with the old struct list_heads. When a table size is given 1435 * we use the old value of 8 to avoid reducing the max. 1436 * entries. */ 1437 max_factor = 4; 1438 } 1439 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1440 1441 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1442 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1443 nf_conntrack_max); 1444 1445 ret = nf_conntrack_proto_init(); 1446 if (ret < 0) 1447 goto err_proto; 1448 1449 ret = nf_conntrack_helper_init(); 1450 if (ret < 0) 1451 goto err_helper; 1452 1453#ifdef CONFIG_NF_CONNTRACK_ZONES 1454 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1455 if (ret < 0) 1456 goto err_extend; 1457#endif 1458 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1459 for_each_possible_cpu(cpu) { 1460 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1461 write_pnet(&ct->ct_net, &init_net); 1462 atomic_set(&ct->ct_general.use, 1); 1463 } 1464 /* - and look it like as a confirmed connection */ 1465 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1466 return 0; 1467 1468#ifdef CONFIG_NF_CONNTRACK_ZONES 1469err_extend: 1470 nf_conntrack_helper_fini(); 1471#endif 1472err_helper: 1473 nf_conntrack_proto_fini(); 1474err_proto: 1475 return ret; 1476} 1477 1478/* 1479 * We need to use special "null" values, not used in hash table 1480 */ 1481#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1482#define DYING_NULLS_VAL ((1<<30)+1) 1483 1484static int nf_conntrack_init_net(struct net *net) 1485{ 1486 int ret; 1487 1488 atomic_set(&net->ct.count, 0); 1489 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1490 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1491 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1492 if (!net->ct.stat) { 1493 ret = -ENOMEM; 1494 goto err_stat; 1495 } 1496 1497 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1498 if (!net->ct.slabname) { 1499 ret = -ENOMEM; 1500 goto err_slabname; 1501 } 1502 1503 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1504 sizeof(struct nf_conn), 0, 1505 SLAB_DESTROY_BY_RCU, NULL); 1506 if (!net->ct.nf_conntrack_cachep) { 1507 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1508 ret = -ENOMEM; 1509 goto err_cache; 1510 } 1511 1512 net->ct.htable_size = nf_conntrack_htable_size; 1513 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1); 1514 if (!net->ct.hash) { 1515 ret = -ENOMEM; 1516 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1517 goto err_hash; 1518 } 1519 ret = nf_conntrack_expect_init(net); 1520 if (ret < 0) 1521 goto err_expect; 1522 ret = nf_conntrack_acct_init(net); 1523 if (ret < 0) 1524 goto err_acct; 1525 ret = nf_conntrack_tstamp_init(net); 1526 if (ret < 0) 1527 goto err_tstamp; 1528 ret = nf_conntrack_ecache_init(net); 1529 if (ret < 0) 1530 goto err_ecache; 1531 1532 return 0; 1533 1534err_ecache: 1535 nf_conntrack_tstamp_fini(net); 1536err_tstamp: 1537 nf_conntrack_acct_fini(net); 1538err_acct: 1539 nf_conntrack_expect_fini(net); 1540err_expect: 1541 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1542err_hash: 1543 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1544err_cache: 1545 kfree(net->ct.slabname); 1546err_slabname: 1547 free_percpu(net->ct.stat); 1548err_stat: 1549 return ret; 1550} 1551 1552s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1553 enum ip_conntrack_dir dir, 1554 u32 seq); 1555EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1556 1557int nf_conntrack_init(struct net *net) 1558{ 1559 int ret; 1560 1561 if (net_eq(net, &init_net)) { 1562 ret = nf_conntrack_init_init_net(); 1563 if (ret < 0) 1564 goto out_init_net; 1565 } 1566 ret = nf_conntrack_init_net(net); 1567 if (ret < 0) 1568 goto out_net; 1569 1570 if (net_eq(net, &init_net)) { 1571 /* For use by REJECT target */ 1572 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach); 1573 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack); 1574 1575 /* Howto get NAT offsets */ 1576 RCU_INIT_POINTER(nf_ct_nat_offset, NULL); 1577 } 1578 return 0; 1579 1580out_net: 1581 if (net_eq(net, &init_net)) 1582 nf_conntrack_cleanup_init_net(); 1583out_init_net: 1584 return ret; 1585} 1586