nf_conntrack_core.c revision 493763684fefca54502e2d95b057075ac8e279ea
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_conntrack_timeout.h> 48#include <net/netfilter/nf_conntrack_labels.h> 49#include <net/netfilter/nf_nat.h> 50#include <net/netfilter/nf_nat_core.h> 51#include <net/netfilter/nf_nat_helper.h> 52 53#define NF_CONNTRACK_VERSION "0.5.0" 54 55int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 56 enum nf_nat_manip_type manip, 57 const struct nlattr *attr) __read_mostly; 58EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 59 60int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb, 61 struct nf_conn *ct, 62 enum ip_conntrack_info ctinfo, 63 unsigned int protoff); 64EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook); 65 66DEFINE_SPINLOCK(nf_conntrack_lock); 67EXPORT_SYMBOL_GPL(nf_conntrack_lock); 68 69unsigned int nf_conntrack_htable_size __read_mostly; 70EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 71 72unsigned int nf_conntrack_max __read_mostly; 73EXPORT_SYMBOL_GPL(nf_conntrack_max); 74 75DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 76EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 77 78unsigned int nf_conntrack_hash_rnd __read_mostly; 79EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd); 80 81static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 82{ 83 unsigned int n; 84 85 /* The direction must be ignored, so we hash everything up to the 86 * destination ports (which is a multiple of 4) and treat the last 87 * three bytes manually. 88 */ 89 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 90 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 91 (((__force __u16)tuple->dst.u.all << 16) | 92 tuple->dst.protonum)); 93} 94 95static u32 __hash_bucket(u32 hash, unsigned int size) 96{ 97 return ((u64)hash * size) >> 32; 98} 99 100static u32 hash_bucket(u32 hash, const struct net *net) 101{ 102 return __hash_bucket(hash, net->ct.htable_size); 103} 104 105static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 106 u16 zone, unsigned int size) 107{ 108 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 109} 110 111static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 112 const struct nf_conntrack_tuple *tuple) 113{ 114 return __hash_conntrack(tuple, zone, net->ct.htable_size); 115} 116 117bool 118nf_ct_get_tuple(const struct sk_buff *skb, 119 unsigned int nhoff, 120 unsigned int dataoff, 121 u_int16_t l3num, 122 u_int8_t protonum, 123 struct nf_conntrack_tuple *tuple, 124 const struct nf_conntrack_l3proto *l3proto, 125 const struct nf_conntrack_l4proto *l4proto) 126{ 127 memset(tuple, 0, sizeof(*tuple)); 128 129 tuple->src.l3num = l3num; 130 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 131 return false; 132 133 tuple->dst.protonum = protonum; 134 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 135 136 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 137} 138EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 139 140bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 141 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 142{ 143 struct nf_conntrack_l3proto *l3proto; 144 struct nf_conntrack_l4proto *l4proto; 145 unsigned int protoff; 146 u_int8_t protonum; 147 int ret; 148 149 rcu_read_lock(); 150 151 l3proto = __nf_ct_l3proto_find(l3num); 152 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 153 if (ret != NF_ACCEPT) { 154 rcu_read_unlock(); 155 return false; 156 } 157 158 l4proto = __nf_ct_l4proto_find(l3num, protonum); 159 160 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 161 l3proto, l4proto); 162 163 rcu_read_unlock(); 164 return ret; 165} 166EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 167 168bool 169nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 170 const struct nf_conntrack_tuple *orig, 171 const struct nf_conntrack_l3proto *l3proto, 172 const struct nf_conntrack_l4proto *l4proto) 173{ 174 memset(inverse, 0, sizeof(*inverse)); 175 176 inverse->src.l3num = orig->src.l3num; 177 if (l3proto->invert_tuple(inverse, orig) == 0) 178 return false; 179 180 inverse->dst.dir = !orig->dst.dir; 181 182 inverse->dst.protonum = orig->dst.protonum; 183 return l4proto->invert_tuple(inverse, orig); 184} 185EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 186 187static void 188clean_from_lists(struct nf_conn *ct) 189{ 190 pr_debug("clean_from_lists(%p)\n", ct); 191 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 192 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 193 194 /* Destroy all pending expectations */ 195 nf_ct_remove_expectations(ct); 196} 197 198static void 199destroy_conntrack(struct nf_conntrack *nfct) 200{ 201 struct nf_conn *ct = (struct nf_conn *)nfct; 202 struct net *net = nf_ct_net(ct); 203 struct nf_conntrack_l4proto *l4proto; 204 205 pr_debug("destroy_conntrack(%p)\n", ct); 206 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 207 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 208 209 /* To make sure we don't get any weird locking issues here: 210 * destroy_conntrack() MUST NOT be called with a write lock 211 * to nf_conntrack_lock!!! -HW */ 212 rcu_read_lock(); 213 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 214 if (l4proto && l4proto->destroy) 215 l4proto->destroy(ct); 216 217 rcu_read_unlock(); 218 219 spin_lock_bh(&nf_conntrack_lock); 220 /* Expectations will have been removed in clean_from_lists, 221 * except TFTP can create an expectation on the first packet, 222 * before connection is in the list, so we need to clean here, 223 * too. */ 224 nf_ct_remove_expectations(ct); 225 226 /* We overload first tuple to link into unconfirmed or dying list.*/ 227 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 228 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 229 230 NF_CT_STAT_INC(net, delete); 231 spin_unlock_bh(&nf_conntrack_lock); 232 233 if (ct->master) 234 nf_ct_put(ct->master); 235 236 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 237 nf_conntrack_free(ct); 238} 239 240void nf_ct_delete_from_lists(struct nf_conn *ct) 241{ 242 struct net *net = nf_ct_net(ct); 243 244 nf_ct_helper_destroy(ct); 245 spin_lock_bh(&nf_conntrack_lock); 246 /* Inside lock so preempt is disabled on module removal path. 247 * Otherwise we can get spurious warnings. */ 248 NF_CT_STAT_INC(net, delete_list); 249 clean_from_lists(ct); 250 /* add this conntrack to the dying list */ 251 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 252 &net->ct.dying); 253 spin_unlock_bh(&nf_conntrack_lock); 254} 255EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 256 257static void death_by_event(unsigned long ul_conntrack) 258{ 259 struct nf_conn *ct = (void *)ul_conntrack; 260 struct net *net = nf_ct_net(ct); 261 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 262 263 BUG_ON(ecache == NULL); 264 265 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 266 /* bad luck, let's retry again */ 267 ecache->timeout.expires = jiffies + 268 (random32() % net->ct.sysctl_events_retry_timeout); 269 add_timer(&ecache->timeout); 270 return; 271 } 272 /* we've got the event delivered, now it's dying */ 273 set_bit(IPS_DYING_BIT, &ct->status); 274 nf_ct_put(ct); 275} 276 277void nf_ct_dying_timeout(struct nf_conn *ct) 278{ 279 struct net *net = nf_ct_net(ct); 280 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 281 282 BUG_ON(ecache == NULL); 283 284 /* set a new timer to retry event delivery */ 285 setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct); 286 ecache->timeout.expires = jiffies + 287 (random32() % net->ct.sysctl_events_retry_timeout); 288 add_timer(&ecache->timeout); 289} 290EXPORT_SYMBOL_GPL(nf_ct_dying_timeout); 291 292static void death_by_timeout(unsigned long ul_conntrack) 293{ 294 struct nf_conn *ct = (void *)ul_conntrack; 295 struct nf_conn_tstamp *tstamp; 296 297 tstamp = nf_conn_tstamp_find(ct); 298 if (tstamp && tstamp->stop == 0) 299 tstamp->stop = ktime_to_ns(ktime_get_real()); 300 301 if (!test_bit(IPS_DYING_BIT, &ct->status) && 302 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 303 /* destroy event was not delivered */ 304 nf_ct_delete_from_lists(ct); 305 nf_ct_dying_timeout(ct); 306 return; 307 } 308 set_bit(IPS_DYING_BIT, &ct->status); 309 nf_ct_delete_from_lists(ct); 310 nf_ct_put(ct); 311} 312 313/* 314 * Warning : 315 * - Caller must take a reference on returned object 316 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 317 * OR 318 * - Caller must lock nf_conntrack_lock before calling this function 319 */ 320static struct nf_conntrack_tuple_hash * 321____nf_conntrack_find(struct net *net, u16 zone, 322 const struct nf_conntrack_tuple *tuple, u32 hash) 323{ 324 struct nf_conntrack_tuple_hash *h; 325 struct hlist_nulls_node *n; 326 unsigned int bucket = hash_bucket(hash, net); 327 328 /* Disable BHs the entire time since we normally need to disable them 329 * at least once for the stats anyway. 330 */ 331 local_bh_disable(); 332begin: 333 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) { 334 if (nf_ct_tuple_equal(tuple, &h->tuple) && 335 nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { 336 NF_CT_STAT_INC(net, found); 337 local_bh_enable(); 338 return h; 339 } 340 NF_CT_STAT_INC(net, searched); 341 } 342 /* 343 * if the nulls value we got at the end of this lookup is 344 * not the expected one, we must restart lookup. 345 * We probably met an item that was moved to another chain. 346 */ 347 if (get_nulls_value(n) != bucket) { 348 NF_CT_STAT_INC(net, search_restart); 349 goto begin; 350 } 351 local_bh_enable(); 352 353 return NULL; 354} 355 356struct nf_conntrack_tuple_hash * 357__nf_conntrack_find(struct net *net, u16 zone, 358 const struct nf_conntrack_tuple *tuple) 359{ 360 return ____nf_conntrack_find(net, zone, tuple, 361 hash_conntrack_raw(tuple, zone)); 362} 363EXPORT_SYMBOL_GPL(__nf_conntrack_find); 364 365/* Find a connection corresponding to a tuple. */ 366static struct nf_conntrack_tuple_hash * 367__nf_conntrack_find_get(struct net *net, u16 zone, 368 const struct nf_conntrack_tuple *tuple, u32 hash) 369{ 370 struct nf_conntrack_tuple_hash *h; 371 struct nf_conn *ct; 372 373 rcu_read_lock(); 374begin: 375 h = ____nf_conntrack_find(net, zone, tuple, hash); 376 if (h) { 377 ct = nf_ct_tuplehash_to_ctrack(h); 378 if (unlikely(nf_ct_is_dying(ct) || 379 !atomic_inc_not_zero(&ct->ct_general.use))) 380 h = NULL; 381 else { 382 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || 383 nf_ct_zone(ct) != zone)) { 384 nf_ct_put(ct); 385 goto begin; 386 } 387 } 388 } 389 rcu_read_unlock(); 390 391 return h; 392} 393 394struct nf_conntrack_tuple_hash * 395nf_conntrack_find_get(struct net *net, u16 zone, 396 const struct nf_conntrack_tuple *tuple) 397{ 398 return __nf_conntrack_find_get(net, zone, tuple, 399 hash_conntrack_raw(tuple, zone)); 400} 401EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 402 403static void __nf_conntrack_hash_insert(struct nf_conn *ct, 404 unsigned int hash, 405 unsigned int repl_hash) 406{ 407 struct net *net = nf_ct_net(ct); 408 409 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 410 &net->ct.hash[hash]); 411 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 412 &net->ct.hash[repl_hash]); 413} 414 415int 416nf_conntrack_hash_check_insert(struct nf_conn *ct) 417{ 418 struct net *net = nf_ct_net(ct); 419 unsigned int hash, repl_hash; 420 struct nf_conntrack_tuple_hash *h; 421 struct hlist_nulls_node *n; 422 u16 zone; 423 424 zone = nf_ct_zone(ct); 425 hash = hash_conntrack(net, zone, 426 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 427 repl_hash = hash_conntrack(net, zone, 428 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 429 430 spin_lock_bh(&nf_conntrack_lock); 431 432 /* See if there's one in the list already, including reverse */ 433 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 434 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 435 &h->tuple) && 436 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 437 goto out; 438 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 439 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 440 &h->tuple) && 441 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 442 goto out; 443 444 add_timer(&ct->timeout); 445 nf_conntrack_get(&ct->ct_general); 446 __nf_conntrack_hash_insert(ct, hash, repl_hash); 447 NF_CT_STAT_INC(net, insert); 448 spin_unlock_bh(&nf_conntrack_lock); 449 450 return 0; 451 452out: 453 NF_CT_STAT_INC(net, insert_failed); 454 spin_unlock_bh(&nf_conntrack_lock); 455 return -EEXIST; 456} 457EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); 458 459/* Confirm a connection given skb; places it in hash table */ 460int 461__nf_conntrack_confirm(struct sk_buff *skb) 462{ 463 unsigned int hash, repl_hash; 464 struct nf_conntrack_tuple_hash *h; 465 struct nf_conn *ct; 466 struct nf_conn_help *help; 467 struct nf_conn_tstamp *tstamp; 468 struct hlist_nulls_node *n; 469 enum ip_conntrack_info ctinfo; 470 struct net *net; 471 u16 zone; 472 473 ct = nf_ct_get(skb, &ctinfo); 474 net = nf_ct_net(ct); 475 476 /* ipt_REJECT uses nf_conntrack_attach to attach related 477 ICMP/TCP RST packets in other direction. Actual packet 478 which created connection will be IP_CT_NEW or for an 479 expected connection, IP_CT_RELATED. */ 480 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 481 return NF_ACCEPT; 482 483 zone = nf_ct_zone(ct); 484 /* reuse the hash saved before */ 485 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 486 hash = hash_bucket(hash, net); 487 repl_hash = hash_conntrack(net, zone, 488 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 489 490 /* We're not in hash table, and we refuse to set up related 491 connections for unconfirmed conns. But packet copies and 492 REJECT will give spurious warnings here. */ 493 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 494 495 /* No external references means no one else could have 496 confirmed us. */ 497 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 498 pr_debug("Confirming conntrack %p\n", ct); 499 500 spin_lock_bh(&nf_conntrack_lock); 501 502 /* We have to check the DYING flag inside the lock to prevent 503 a race against nf_ct_get_next_corpse() possibly called from 504 user context, else we insert an already 'dead' hash, blocking 505 further use of that particular connection -JM */ 506 507 if (unlikely(nf_ct_is_dying(ct))) { 508 spin_unlock_bh(&nf_conntrack_lock); 509 return NF_ACCEPT; 510 } 511 512 /* See if there's one in the list already, including reverse: 513 NAT could have grabbed it without realizing, since we're 514 not in the hash. If there is, we lost race. */ 515 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 516 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 517 &h->tuple) && 518 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 519 goto out; 520 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 521 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 522 &h->tuple) && 523 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 524 goto out; 525 526 /* Remove from unconfirmed list */ 527 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 528 529 /* Timer relative to confirmation time, not original 530 setting time, otherwise we'd get timer wrap in 531 weird delay cases. */ 532 ct->timeout.expires += jiffies; 533 add_timer(&ct->timeout); 534 atomic_inc(&ct->ct_general.use); 535 ct->status |= IPS_CONFIRMED; 536 537 /* set conntrack timestamp, if enabled. */ 538 tstamp = nf_conn_tstamp_find(ct); 539 if (tstamp) { 540 if (skb->tstamp.tv64 == 0) 541 __net_timestamp(skb); 542 543 tstamp->start = ktime_to_ns(skb->tstamp); 544 } 545 /* Since the lookup is lockless, hash insertion must be done after 546 * starting the timer and setting the CONFIRMED bit. The RCU barriers 547 * guarantee that no other CPU can find the conntrack before the above 548 * stores are visible. 549 */ 550 __nf_conntrack_hash_insert(ct, hash, repl_hash); 551 NF_CT_STAT_INC(net, insert); 552 spin_unlock_bh(&nf_conntrack_lock); 553 554 help = nfct_help(ct); 555 if (help && help->helper) 556 nf_conntrack_event_cache(IPCT_HELPER, ct); 557 558 nf_conntrack_event_cache(master_ct(ct) ? 559 IPCT_RELATED : IPCT_NEW, ct); 560 return NF_ACCEPT; 561 562out: 563 NF_CT_STAT_INC(net, insert_failed); 564 spin_unlock_bh(&nf_conntrack_lock); 565 return NF_DROP; 566} 567EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 568 569/* Returns true if a connection correspondings to the tuple (required 570 for NAT). */ 571int 572nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 573 const struct nf_conn *ignored_conntrack) 574{ 575 struct net *net = nf_ct_net(ignored_conntrack); 576 struct nf_conntrack_tuple_hash *h; 577 struct hlist_nulls_node *n; 578 struct nf_conn *ct; 579 u16 zone = nf_ct_zone(ignored_conntrack); 580 unsigned int hash = hash_conntrack(net, zone, tuple); 581 582 /* Disable BHs the entire time since we need to disable them at 583 * least once for the stats anyway. 584 */ 585 rcu_read_lock_bh(); 586 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 587 ct = nf_ct_tuplehash_to_ctrack(h); 588 if (ct != ignored_conntrack && 589 nf_ct_tuple_equal(tuple, &h->tuple) && 590 nf_ct_zone(ct) == zone) { 591 NF_CT_STAT_INC(net, found); 592 rcu_read_unlock_bh(); 593 return 1; 594 } 595 NF_CT_STAT_INC(net, searched); 596 } 597 rcu_read_unlock_bh(); 598 599 return 0; 600} 601EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 602 603#define NF_CT_EVICTION_RANGE 8 604 605/* There's a small race here where we may free a just-assured 606 connection. Too bad: we're in trouble anyway. */ 607static noinline int early_drop(struct net *net, unsigned int hash) 608{ 609 /* Use oldest entry, which is roughly LRU */ 610 struct nf_conntrack_tuple_hash *h; 611 struct nf_conn *ct = NULL, *tmp; 612 struct hlist_nulls_node *n; 613 unsigned int i, cnt = 0; 614 int dropped = 0; 615 616 rcu_read_lock(); 617 for (i = 0; i < net->ct.htable_size; i++) { 618 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 619 hnnode) { 620 tmp = nf_ct_tuplehash_to_ctrack(h); 621 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 622 ct = tmp; 623 cnt++; 624 } 625 626 if (ct != NULL) { 627 if (likely(!nf_ct_is_dying(ct) && 628 atomic_inc_not_zero(&ct->ct_general.use))) 629 break; 630 else 631 ct = NULL; 632 } 633 634 if (cnt >= NF_CT_EVICTION_RANGE) 635 break; 636 637 hash = (hash + 1) % net->ct.htable_size; 638 } 639 rcu_read_unlock(); 640 641 if (!ct) 642 return dropped; 643 644 if (del_timer(&ct->timeout)) { 645 death_by_timeout((unsigned long)ct); 646 /* Check if we indeed killed this entry. Reliable event 647 delivery may have inserted it into the dying list. */ 648 if (test_bit(IPS_DYING_BIT, &ct->status)) { 649 dropped = 1; 650 NF_CT_STAT_INC_ATOMIC(net, early_drop); 651 } 652 } 653 nf_ct_put(ct); 654 return dropped; 655} 656 657void init_nf_conntrack_hash_rnd(void) 658{ 659 unsigned int rand; 660 661 /* 662 * Why not initialize nf_conntrack_rnd in a "init()" function ? 663 * Because there isn't enough entropy when system initializing, 664 * and we initialize it as late as possible. 665 */ 666 do { 667 get_random_bytes(&rand, sizeof(rand)); 668 } while (!rand); 669 cmpxchg(&nf_conntrack_hash_rnd, 0, rand); 670} 671 672static struct nf_conn * 673__nf_conntrack_alloc(struct net *net, u16 zone, 674 const struct nf_conntrack_tuple *orig, 675 const struct nf_conntrack_tuple *repl, 676 gfp_t gfp, u32 hash) 677{ 678 struct nf_conn *ct; 679 680 if (unlikely(!nf_conntrack_hash_rnd)) { 681 init_nf_conntrack_hash_rnd(); 682 /* recompute the hash as nf_conntrack_hash_rnd is initialized */ 683 hash = hash_conntrack_raw(orig, zone); 684 } 685 686 /* We don't want any race condition at early drop stage */ 687 atomic_inc(&net->ct.count); 688 689 if (nf_conntrack_max && 690 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 691 if (!early_drop(net, hash_bucket(hash, net))) { 692 atomic_dec(&net->ct.count); 693 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n"); 694 return ERR_PTR(-ENOMEM); 695 } 696 } 697 698 /* 699 * Do not use kmem_cache_zalloc(), as this cache uses 700 * SLAB_DESTROY_BY_RCU. 701 */ 702 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 703 if (ct == NULL) { 704 atomic_dec(&net->ct.count); 705 return ERR_PTR(-ENOMEM); 706 } 707 /* 708 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 709 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 710 */ 711 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 712 offsetof(struct nf_conn, proto) - 713 offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 714 spin_lock_init(&ct->lock); 715 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 716 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 717 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 718 /* save hash for reusing when confirming */ 719 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 720 /* Don't set timer yet: wait for confirmation */ 721 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 722 write_pnet(&ct->ct_net, net); 723#ifdef CONFIG_NF_CONNTRACK_ZONES 724 if (zone) { 725 struct nf_conntrack_zone *nf_ct_zone; 726 727 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); 728 if (!nf_ct_zone) 729 goto out_free; 730 nf_ct_zone->id = zone; 731 } 732#endif 733 /* 734 * changes to lookup keys must be done before setting refcnt to 1 735 */ 736 smp_wmb(); 737 atomic_set(&ct->ct_general.use, 1); 738 return ct; 739 740#ifdef CONFIG_NF_CONNTRACK_ZONES 741out_free: 742 atomic_dec(&net->ct.count); 743 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 744 return ERR_PTR(-ENOMEM); 745#endif 746} 747 748struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, 749 const struct nf_conntrack_tuple *orig, 750 const struct nf_conntrack_tuple *repl, 751 gfp_t gfp) 752{ 753 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 754} 755EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 756 757void nf_conntrack_free(struct nf_conn *ct) 758{ 759 struct net *net = nf_ct_net(ct); 760 761 nf_ct_ext_destroy(ct); 762 atomic_dec(&net->ct.count); 763 nf_ct_ext_free(ct); 764 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 765} 766EXPORT_SYMBOL_GPL(nf_conntrack_free); 767 768 769/* Allocate a new conntrack: we return -ENOMEM if classification 770 failed due to stress. Otherwise it really is unclassifiable. */ 771static struct nf_conntrack_tuple_hash * 772init_conntrack(struct net *net, struct nf_conn *tmpl, 773 const struct nf_conntrack_tuple *tuple, 774 struct nf_conntrack_l3proto *l3proto, 775 struct nf_conntrack_l4proto *l4proto, 776 struct sk_buff *skb, 777 unsigned int dataoff, u32 hash) 778{ 779 struct nf_conn *ct; 780 struct nf_conn_help *help; 781 struct nf_conntrack_tuple repl_tuple; 782 struct nf_conntrack_ecache *ecache; 783 struct nf_conntrack_expect *exp; 784 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 785 struct nf_conn_timeout *timeout_ext; 786 unsigned int *timeouts; 787 788 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 789 pr_debug("Can't invert tuple.\n"); 790 return NULL; 791 } 792 793 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 794 hash); 795 if (IS_ERR(ct)) 796 return (struct nf_conntrack_tuple_hash *)ct; 797 798 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; 799 if (timeout_ext) 800 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext); 801 else 802 timeouts = l4proto->get_timeouts(net); 803 804 if (!l4proto->new(ct, skb, dataoff, timeouts)) { 805 nf_conntrack_free(ct); 806 pr_debug("init conntrack: can't track with proto module\n"); 807 return NULL; 808 } 809 810 if (timeout_ext) 811 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC); 812 813 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 814 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 815 nf_ct_labels_ext_add(ct); 816 817 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 818 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 819 ecache ? ecache->expmask : 0, 820 GFP_ATOMIC); 821 822 spin_lock_bh(&nf_conntrack_lock); 823 exp = nf_ct_find_expectation(net, zone, tuple); 824 if (exp) { 825 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 826 ct, exp); 827 /* Welcome, Mr. Bond. We've been expecting you... */ 828 __set_bit(IPS_EXPECTED_BIT, &ct->status); 829 ct->master = exp->master; 830 if (exp->helper) { 831 help = nf_ct_helper_ext_add(ct, exp->helper, 832 GFP_ATOMIC); 833 if (help) 834 rcu_assign_pointer(help->helper, exp->helper); 835 } 836 837#ifdef CONFIG_NF_CONNTRACK_MARK 838 ct->mark = exp->master->mark; 839#endif 840#ifdef CONFIG_NF_CONNTRACK_SECMARK 841 ct->secmark = exp->master->secmark; 842#endif 843 nf_conntrack_get(&ct->master->ct_general); 844 NF_CT_STAT_INC(net, expect_new); 845 } else { 846 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 847 NF_CT_STAT_INC(net, new); 848 } 849 850 /* Overload tuple linked list to put us in unconfirmed list. */ 851 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 852 &net->ct.unconfirmed); 853 854 spin_unlock_bh(&nf_conntrack_lock); 855 856 if (exp) { 857 if (exp->expectfn) 858 exp->expectfn(ct, exp); 859 nf_ct_expect_put(exp); 860 } 861 862 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 863} 864 865/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 866static inline struct nf_conn * 867resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 868 struct sk_buff *skb, 869 unsigned int dataoff, 870 u_int16_t l3num, 871 u_int8_t protonum, 872 struct nf_conntrack_l3proto *l3proto, 873 struct nf_conntrack_l4proto *l4proto, 874 int *set_reply, 875 enum ip_conntrack_info *ctinfo) 876{ 877 struct nf_conntrack_tuple tuple; 878 struct nf_conntrack_tuple_hash *h; 879 struct nf_conn *ct; 880 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 881 u32 hash; 882 883 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 884 dataoff, l3num, protonum, &tuple, l3proto, 885 l4proto)) { 886 pr_debug("resolve_normal_ct: Can't get tuple\n"); 887 return NULL; 888 } 889 890 /* look for tuple match */ 891 hash = hash_conntrack_raw(&tuple, zone); 892 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 893 if (!h) { 894 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 895 skb, dataoff, hash); 896 if (!h) 897 return NULL; 898 if (IS_ERR(h)) 899 return (void *)h; 900 } 901 ct = nf_ct_tuplehash_to_ctrack(h); 902 903 /* It exists; we have (non-exclusive) reference. */ 904 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 905 *ctinfo = IP_CT_ESTABLISHED_REPLY; 906 /* Please set reply bit if this packet OK */ 907 *set_reply = 1; 908 } else { 909 /* Once we've had two way comms, always ESTABLISHED. */ 910 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 911 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 912 *ctinfo = IP_CT_ESTABLISHED; 913 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 914 pr_debug("nf_conntrack_in: related packet for %p\n", 915 ct); 916 *ctinfo = IP_CT_RELATED; 917 } else { 918 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 919 *ctinfo = IP_CT_NEW; 920 } 921 *set_reply = 0; 922 } 923 skb->nfct = &ct->ct_general; 924 skb->nfctinfo = *ctinfo; 925 return ct; 926} 927 928unsigned int 929nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 930 struct sk_buff *skb) 931{ 932 struct nf_conn *ct, *tmpl = NULL; 933 enum ip_conntrack_info ctinfo; 934 struct nf_conntrack_l3proto *l3proto; 935 struct nf_conntrack_l4proto *l4proto; 936 unsigned int *timeouts; 937 unsigned int dataoff; 938 u_int8_t protonum; 939 int set_reply = 0; 940 int ret; 941 942 if (skb->nfct) { 943 /* Previously seen (loopback or untracked)? Ignore. */ 944 tmpl = (struct nf_conn *)skb->nfct; 945 if (!nf_ct_is_template(tmpl)) { 946 NF_CT_STAT_INC_ATOMIC(net, ignore); 947 return NF_ACCEPT; 948 } 949 skb->nfct = NULL; 950 } 951 952 /* rcu_read_lock()ed by nf_hook_slow */ 953 l3proto = __nf_ct_l3proto_find(pf); 954 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 955 &dataoff, &protonum); 956 if (ret <= 0) { 957 pr_debug("not prepared to track yet or error occurred\n"); 958 NF_CT_STAT_INC_ATOMIC(net, error); 959 NF_CT_STAT_INC_ATOMIC(net, invalid); 960 ret = -ret; 961 goto out; 962 } 963 964 l4proto = __nf_ct_l4proto_find(pf, protonum); 965 966 /* It may be an special packet, error, unclean... 967 * inverse of the return code tells to the netfilter 968 * core what to do with the packet. */ 969 if (l4proto->error != NULL) { 970 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 971 pf, hooknum); 972 if (ret <= 0) { 973 NF_CT_STAT_INC_ATOMIC(net, error); 974 NF_CT_STAT_INC_ATOMIC(net, invalid); 975 ret = -ret; 976 goto out; 977 } 978 /* ICMP[v6] protocol trackers may assign one conntrack. */ 979 if (skb->nfct) 980 goto out; 981 } 982 983 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 984 l3proto, l4proto, &set_reply, &ctinfo); 985 if (!ct) { 986 /* Not valid part of a connection */ 987 NF_CT_STAT_INC_ATOMIC(net, invalid); 988 ret = NF_ACCEPT; 989 goto out; 990 } 991 992 if (IS_ERR(ct)) { 993 /* Too stressed to deal. */ 994 NF_CT_STAT_INC_ATOMIC(net, drop); 995 ret = NF_DROP; 996 goto out; 997 } 998 999 NF_CT_ASSERT(skb->nfct); 1000 1001 /* Decide what timeout policy we want to apply to this flow. */ 1002 timeouts = nf_ct_timeout_lookup(net, ct, l4proto); 1003 1004 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts); 1005 if (ret <= 0) { 1006 /* Invalid: inverse of the return code tells 1007 * the netfilter core what to do */ 1008 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 1009 nf_conntrack_put(skb->nfct); 1010 skb->nfct = NULL; 1011 NF_CT_STAT_INC_ATOMIC(net, invalid); 1012 if (ret == -NF_DROP) 1013 NF_CT_STAT_INC_ATOMIC(net, drop); 1014 ret = -ret; 1015 goto out; 1016 } 1017 1018 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 1019 nf_conntrack_event_cache(IPCT_REPLY, ct); 1020out: 1021 if (tmpl) { 1022 /* Special case: we have to repeat this hook, assign the 1023 * template again to this packet. We assume that this packet 1024 * has no conntrack assigned. This is used by nf_ct_tcp. */ 1025 if (ret == NF_REPEAT) 1026 skb->nfct = (struct nf_conntrack *)tmpl; 1027 else 1028 nf_ct_put(tmpl); 1029 } 1030 1031 return ret; 1032} 1033EXPORT_SYMBOL_GPL(nf_conntrack_in); 1034 1035bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 1036 const struct nf_conntrack_tuple *orig) 1037{ 1038 bool ret; 1039 1040 rcu_read_lock(); 1041 ret = nf_ct_invert_tuple(inverse, orig, 1042 __nf_ct_l3proto_find(orig->src.l3num), 1043 __nf_ct_l4proto_find(orig->src.l3num, 1044 orig->dst.protonum)); 1045 rcu_read_unlock(); 1046 return ret; 1047} 1048EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 1049 1050/* Alter reply tuple (maybe alter helper). This is for NAT, and is 1051 implicitly racy: see __nf_conntrack_confirm */ 1052void nf_conntrack_alter_reply(struct nf_conn *ct, 1053 const struct nf_conntrack_tuple *newreply) 1054{ 1055 struct nf_conn_help *help = nfct_help(ct); 1056 1057 /* Should be unconfirmed, so not in hash table yet */ 1058 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 1059 1060 pr_debug("Altering reply tuple of %p to ", ct); 1061 nf_ct_dump_tuple(newreply); 1062 1063 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 1064 if (ct->master || (help && !hlist_empty(&help->expectations))) 1065 return; 1066 1067 rcu_read_lock(); 1068 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 1069 rcu_read_unlock(); 1070} 1071EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 1072 1073/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 1074void __nf_ct_refresh_acct(struct nf_conn *ct, 1075 enum ip_conntrack_info ctinfo, 1076 const struct sk_buff *skb, 1077 unsigned long extra_jiffies, 1078 int do_acct) 1079{ 1080 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 1081 NF_CT_ASSERT(skb); 1082 1083 /* Only update if this is not a fixed timeout */ 1084 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 1085 goto acct; 1086 1087 /* If not in hash table, timer will not be active yet */ 1088 if (!nf_ct_is_confirmed(ct)) { 1089 ct->timeout.expires = extra_jiffies; 1090 } else { 1091 unsigned long newtime = jiffies + extra_jiffies; 1092 1093 /* Only update the timeout if the new timeout is at least 1094 HZ jiffies from the old timeout. Need del_timer for race 1095 avoidance (may already be dying). */ 1096 if (newtime - ct->timeout.expires >= HZ) 1097 mod_timer_pending(&ct->timeout, newtime); 1098 } 1099 1100acct: 1101 if (do_acct) { 1102 struct nf_conn_counter *acct; 1103 1104 acct = nf_conn_acct_find(ct); 1105 if (acct) { 1106 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1107 atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes); 1108 } 1109 } 1110} 1111EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1112 1113bool __nf_ct_kill_acct(struct nf_conn *ct, 1114 enum ip_conntrack_info ctinfo, 1115 const struct sk_buff *skb, 1116 int do_acct) 1117{ 1118 if (do_acct) { 1119 struct nf_conn_counter *acct; 1120 1121 acct = nf_conn_acct_find(ct); 1122 if (acct) { 1123 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1124 atomic64_add(skb->len - skb_network_offset(skb), 1125 &acct[CTINFO2DIR(ctinfo)].bytes); 1126 } 1127 } 1128 1129 if (del_timer(&ct->timeout)) { 1130 ct->timeout.function((unsigned long)ct); 1131 return true; 1132 } 1133 return false; 1134} 1135EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1136 1137#ifdef CONFIG_NF_CONNTRACK_ZONES 1138static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1139 .len = sizeof(struct nf_conntrack_zone), 1140 .align = __alignof__(struct nf_conntrack_zone), 1141 .id = NF_CT_EXT_ZONE, 1142}; 1143#endif 1144 1145#if IS_ENABLED(CONFIG_NF_CT_NETLINK) 1146 1147#include <linux/netfilter/nfnetlink.h> 1148#include <linux/netfilter/nfnetlink_conntrack.h> 1149#include <linux/mutex.h> 1150 1151/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1152 * in ip_conntrack_core, since we don't want the protocols to autoload 1153 * or depend on ctnetlink */ 1154int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1155 const struct nf_conntrack_tuple *tuple) 1156{ 1157 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) || 1158 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port)) 1159 goto nla_put_failure; 1160 return 0; 1161 1162nla_put_failure: 1163 return -1; 1164} 1165EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1166 1167const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1168 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1169 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1170}; 1171EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1172 1173int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1174 struct nf_conntrack_tuple *t) 1175{ 1176 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1177 return -EINVAL; 1178 1179 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1180 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1181 1182 return 0; 1183} 1184EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1185 1186int nf_ct_port_nlattr_tuple_size(void) 1187{ 1188 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1189} 1190EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1191#endif 1192 1193/* Used by ipt_REJECT and ip6t_REJECT. */ 1194static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1195{ 1196 struct nf_conn *ct; 1197 enum ip_conntrack_info ctinfo; 1198 1199 /* This ICMP is in reverse direction to the packet which caused it */ 1200 ct = nf_ct_get(skb, &ctinfo); 1201 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1202 ctinfo = IP_CT_RELATED_REPLY; 1203 else 1204 ctinfo = IP_CT_RELATED; 1205 1206 /* Attach to new skbuff, and increment count */ 1207 nskb->nfct = &ct->ct_general; 1208 nskb->nfctinfo = ctinfo; 1209 nf_conntrack_get(nskb->nfct); 1210} 1211 1212/* Bring out ya dead! */ 1213static struct nf_conn * 1214get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1215 void *data, unsigned int *bucket) 1216{ 1217 struct nf_conntrack_tuple_hash *h; 1218 struct nf_conn *ct; 1219 struct hlist_nulls_node *n; 1220 1221 spin_lock_bh(&nf_conntrack_lock); 1222 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1223 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1224 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL) 1225 continue; 1226 ct = nf_ct_tuplehash_to_ctrack(h); 1227 if (iter(ct, data)) 1228 goto found; 1229 } 1230 } 1231 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1232 ct = nf_ct_tuplehash_to_ctrack(h); 1233 if (iter(ct, data)) 1234 set_bit(IPS_DYING_BIT, &ct->status); 1235 } 1236 spin_unlock_bh(&nf_conntrack_lock); 1237 return NULL; 1238found: 1239 atomic_inc(&ct->ct_general.use); 1240 spin_unlock_bh(&nf_conntrack_lock); 1241 return ct; 1242} 1243 1244void nf_ct_iterate_cleanup(struct net *net, 1245 int (*iter)(struct nf_conn *i, void *data), 1246 void *data) 1247{ 1248 struct nf_conn *ct; 1249 unsigned int bucket = 0; 1250 1251 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1252 /* Time to push up daises... */ 1253 if (del_timer(&ct->timeout)) 1254 death_by_timeout((unsigned long)ct); 1255 /* ... else the timer will get him soon. */ 1256 1257 nf_ct_put(ct); 1258 } 1259} 1260EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1261 1262struct __nf_ct_flush_report { 1263 u32 pid; 1264 int report; 1265}; 1266 1267static int kill_report(struct nf_conn *i, void *data) 1268{ 1269 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1270 struct nf_conn_tstamp *tstamp; 1271 1272 tstamp = nf_conn_tstamp_find(i); 1273 if (tstamp && tstamp->stop == 0) 1274 tstamp->stop = ktime_to_ns(ktime_get_real()); 1275 1276 /* If we fail to deliver the event, death_by_timeout() will retry */ 1277 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1278 fr->pid, fr->report) < 0) 1279 return 1; 1280 1281 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1282 set_bit(IPS_DYING_BIT, &i->status); 1283 return 1; 1284} 1285 1286static int kill_all(struct nf_conn *i, void *data) 1287{ 1288 return 1; 1289} 1290 1291void nf_ct_free_hashtable(void *hash, unsigned int size) 1292{ 1293 if (is_vmalloc_addr(hash)) 1294 vfree(hash); 1295 else 1296 free_pages((unsigned long)hash, 1297 get_order(sizeof(struct hlist_head) * size)); 1298} 1299EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1300 1301void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1302{ 1303 struct __nf_ct_flush_report fr = { 1304 .pid = pid, 1305 .report = report, 1306 }; 1307 nf_ct_iterate_cleanup(net, kill_report, &fr); 1308} 1309EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1310 1311static void nf_ct_release_dying_list(struct net *net) 1312{ 1313 struct nf_conntrack_tuple_hash *h; 1314 struct nf_conn *ct; 1315 struct hlist_nulls_node *n; 1316 1317 spin_lock_bh(&nf_conntrack_lock); 1318 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1319 ct = nf_ct_tuplehash_to_ctrack(h); 1320 /* never fails to remove them, no listeners at this point */ 1321 nf_ct_kill(ct); 1322 } 1323 spin_unlock_bh(&nf_conntrack_lock); 1324} 1325 1326static int untrack_refs(void) 1327{ 1328 int cnt = 0, cpu; 1329 1330 for_each_possible_cpu(cpu) { 1331 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1332 1333 cnt += atomic_read(&ct->ct_general.use) - 1; 1334 } 1335 return cnt; 1336} 1337 1338void nf_conntrack_cleanup_start(void) 1339{ 1340 RCU_INIT_POINTER(ip_ct_attach, NULL); 1341} 1342 1343void nf_conntrack_cleanup_end(void) 1344{ 1345 RCU_INIT_POINTER(nf_ct_destroy, NULL); 1346 while (untrack_refs() > 0) 1347 schedule(); 1348 1349#ifdef CONFIG_NF_CONNTRACK_ZONES 1350 nf_ct_extend_unregister(&nf_ct_zone_extend); 1351#endif 1352 nf_conntrack_proto_fini(); 1353 nf_conntrack_labels_fini(); 1354 nf_conntrack_helper_fini(); 1355 nf_conntrack_timeout_fini(); 1356 nf_conntrack_ecache_fini(); 1357 nf_conntrack_tstamp_fini(); 1358 nf_conntrack_acct_fini(); 1359 nf_conntrack_expect_fini(); 1360} 1361 1362/* 1363 * Mishearing the voices in his head, our hero wonders how he's 1364 * supposed to kill the mall. 1365 */ 1366void nf_conntrack_cleanup_net(struct net *net) 1367{ 1368 /* 1369 * This makes sure all current packets have passed through 1370 * netfilter framework. Roll on, two-stage module 1371 * delete... 1372 */ 1373 synchronize_net(); 1374 i_see_dead_people: 1375 nf_ct_iterate_cleanup(net, kill_all, NULL); 1376 nf_ct_release_dying_list(net); 1377 if (atomic_read(&net->ct.count) != 0) { 1378 schedule(); 1379 goto i_see_dead_people; 1380 } 1381 1382 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1383 nf_conntrack_proto_pernet_fini(net); 1384 nf_conntrack_helper_pernet_fini(net); 1385 nf_conntrack_ecache_pernet_fini(net); 1386 nf_conntrack_tstamp_pernet_fini(net); 1387 nf_conntrack_acct_pernet_fini(net); 1388 nf_conntrack_expect_pernet_fini(net); 1389 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1390 kfree(net->ct.slabname); 1391 free_percpu(net->ct.stat); 1392} 1393 1394void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 1395{ 1396 struct hlist_nulls_head *hash; 1397 unsigned int nr_slots, i; 1398 size_t sz; 1399 1400 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1401 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1402 sz = nr_slots * sizeof(struct hlist_nulls_head); 1403 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1404 get_order(sz)); 1405 if (!hash) { 1406 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1407 hash = vzalloc(sz); 1408 } 1409 1410 if (hash && nulls) 1411 for (i = 0; i < nr_slots; i++) 1412 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1413 1414 return hash; 1415} 1416EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1417 1418int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1419{ 1420 int i, bucket, rc; 1421 unsigned int hashsize, old_size; 1422 struct hlist_nulls_head *hash, *old_hash; 1423 struct nf_conntrack_tuple_hash *h; 1424 struct nf_conn *ct; 1425 1426 if (current->nsproxy->net_ns != &init_net) 1427 return -EOPNOTSUPP; 1428 1429 /* On boot, we can set this without any fancy locking. */ 1430 if (!nf_conntrack_htable_size) 1431 return param_set_uint(val, kp); 1432 1433 rc = kstrtouint(val, 0, &hashsize); 1434 if (rc) 1435 return rc; 1436 if (!hashsize) 1437 return -EINVAL; 1438 1439 hash = nf_ct_alloc_hashtable(&hashsize, 1); 1440 if (!hash) 1441 return -ENOMEM; 1442 1443 /* Lookups in the old hash might happen in parallel, which means we 1444 * might get false negatives during connection lookup. New connections 1445 * created because of a false negative won't make it into the hash 1446 * though since that required taking the lock. 1447 */ 1448 spin_lock_bh(&nf_conntrack_lock); 1449 for (i = 0; i < init_net.ct.htable_size; i++) { 1450 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1451 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1452 struct nf_conntrack_tuple_hash, hnnode); 1453 ct = nf_ct_tuplehash_to_ctrack(h); 1454 hlist_nulls_del_rcu(&h->hnnode); 1455 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1456 hashsize); 1457 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1458 } 1459 } 1460 old_size = init_net.ct.htable_size; 1461 old_hash = init_net.ct.hash; 1462 1463 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1464 init_net.ct.hash = hash; 1465 spin_unlock_bh(&nf_conntrack_lock); 1466 1467 nf_ct_free_hashtable(old_hash, old_size); 1468 return 0; 1469} 1470EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1471 1472module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1473 &nf_conntrack_htable_size, 0600); 1474 1475void nf_ct_untracked_status_or(unsigned long bits) 1476{ 1477 int cpu; 1478 1479 for_each_possible_cpu(cpu) 1480 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1481} 1482EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1483 1484int nf_conntrack_init_start(void) 1485{ 1486 int max_factor = 8; 1487 int ret, cpu; 1488 1489 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1490 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1491 if (!nf_conntrack_htable_size) { 1492 nf_conntrack_htable_size 1493 = (((totalram_pages << PAGE_SHIFT) / 16384) 1494 / sizeof(struct hlist_head)); 1495 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1496 nf_conntrack_htable_size = 16384; 1497 if (nf_conntrack_htable_size < 32) 1498 nf_conntrack_htable_size = 32; 1499 1500 /* Use a max. factor of four by default to get the same max as 1501 * with the old struct list_heads. When a table size is given 1502 * we use the old value of 8 to avoid reducing the max. 1503 * entries. */ 1504 max_factor = 4; 1505 } 1506 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1507 1508 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1509 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1510 nf_conntrack_max); 1511 1512 ret = nf_conntrack_expect_init(); 1513 if (ret < 0) 1514 goto err_expect; 1515 1516 ret = nf_conntrack_acct_init(); 1517 if (ret < 0) 1518 goto err_acct; 1519 1520 ret = nf_conntrack_tstamp_init(); 1521 if (ret < 0) 1522 goto err_tstamp; 1523 1524 ret = nf_conntrack_ecache_init(); 1525 if (ret < 0) 1526 goto err_ecache; 1527 1528 ret = nf_conntrack_timeout_init(); 1529 if (ret < 0) 1530 goto err_timeout; 1531 1532 ret = nf_conntrack_helper_init(); 1533 if (ret < 0) 1534 goto err_helper; 1535 1536 ret = nf_conntrack_labels_init(); 1537 if (ret < 0) 1538 goto err_labels; 1539 1540#ifdef CONFIG_NF_CONNTRACK_ZONES 1541 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1542 if (ret < 0) 1543 goto err_extend; 1544#endif 1545 ret = nf_conntrack_proto_init(); 1546 if (ret < 0) 1547 goto err_proto; 1548 1549 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1550 for_each_possible_cpu(cpu) { 1551 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1552 write_pnet(&ct->ct_net, &init_net); 1553 atomic_set(&ct->ct_general.use, 1); 1554 } 1555 /* - and look it like as a confirmed connection */ 1556 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1557 return 0; 1558 1559err_proto: 1560#ifdef CONFIG_NF_CONNTRACK_ZONES 1561 nf_ct_extend_unregister(&nf_ct_zone_extend); 1562err_extend: 1563#endif 1564 nf_conntrack_labels_fini(); 1565err_labels: 1566 nf_conntrack_helper_fini(); 1567err_helper: 1568 nf_conntrack_timeout_fini(); 1569err_timeout: 1570 nf_conntrack_ecache_fini(); 1571err_ecache: 1572 nf_conntrack_tstamp_fini(); 1573err_tstamp: 1574 nf_conntrack_acct_fini(); 1575err_acct: 1576 nf_conntrack_expect_fini(); 1577err_expect: 1578 return ret; 1579} 1580 1581void nf_conntrack_init_end(void) 1582{ 1583 /* For use by REJECT target */ 1584 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach); 1585 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack); 1586 1587 /* Howto get NAT offsets */ 1588 RCU_INIT_POINTER(nf_ct_nat_offset, NULL); 1589} 1590 1591/* 1592 * We need to use special "null" values, not used in hash table 1593 */ 1594#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1595#define DYING_NULLS_VAL ((1<<30)+1) 1596#define TEMPLATE_NULLS_VAL ((1<<30)+2) 1597 1598int nf_conntrack_init_net(struct net *net) 1599{ 1600 int ret; 1601 1602 atomic_set(&net->ct.count, 0); 1603 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1604 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1605 INIT_HLIST_NULLS_HEAD(&net->ct.tmpl, TEMPLATE_NULLS_VAL); 1606 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1607 if (!net->ct.stat) { 1608 ret = -ENOMEM; 1609 goto err_stat; 1610 } 1611 1612 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1613 if (!net->ct.slabname) { 1614 ret = -ENOMEM; 1615 goto err_slabname; 1616 } 1617 1618 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1619 sizeof(struct nf_conn), 0, 1620 SLAB_DESTROY_BY_RCU, NULL); 1621 if (!net->ct.nf_conntrack_cachep) { 1622 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1623 ret = -ENOMEM; 1624 goto err_cache; 1625 } 1626 1627 net->ct.htable_size = nf_conntrack_htable_size; 1628 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1); 1629 if (!net->ct.hash) { 1630 ret = -ENOMEM; 1631 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1632 goto err_hash; 1633 } 1634 ret = nf_conntrack_expect_pernet_init(net); 1635 if (ret < 0) 1636 goto err_expect; 1637 ret = nf_conntrack_acct_pernet_init(net); 1638 if (ret < 0) 1639 goto err_acct; 1640 ret = nf_conntrack_tstamp_pernet_init(net); 1641 if (ret < 0) 1642 goto err_tstamp; 1643 ret = nf_conntrack_ecache_pernet_init(net); 1644 if (ret < 0) 1645 goto err_ecache; 1646 ret = nf_conntrack_helper_pernet_init(net); 1647 if (ret < 0) 1648 goto err_helper; 1649 ret = nf_conntrack_proto_pernet_init(net); 1650 if (ret < 0) 1651 goto err_proto; 1652 return 0; 1653 1654err_proto: 1655 nf_conntrack_helper_pernet_fini(net); 1656err_helper: 1657 nf_conntrack_ecache_pernet_fini(net); 1658err_ecache: 1659 nf_conntrack_tstamp_pernet_fini(net); 1660err_tstamp: 1661 nf_conntrack_acct_pernet_fini(net); 1662err_acct: 1663 nf_conntrack_expect_pernet_fini(net); 1664err_expect: 1665 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1666err_hash: 1667 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1668err_cache: 1669 kfree(net->ct.slabname); 1670err_slabname: 1671 free_percpu(net->ct.stat); 1672err_stat: 1673 return ret; 1674} 1675 1676s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1677 enum ip_conntrack_dir dir, 1678 u32 seq); 1679EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1680