nf_conntrack_core.c revision 5b423f6a40a0327f9d40bc8b97ce9be266f74368
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_nat.h> 49#include <net/netfilter/nf_nat_core.h> 50 51#define NF_CONNTRACK_VERSION "0.5.0" 52 53int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 54 enum nf_nat_manip_type manip, 55 const struct nlattr *attr) __read_mostly; 56EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 57 58DEFINE_SPINLOCK(nf_conntrack_lock); 59EXPORT_SYMBOL_GPL(nf_conntrack_lock); 60 61unsigned int nf_conntrack_htable_size __read_mostly; 62EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 63 64unsigned int nf_conntrack_max __read_mostly; 65EXPORT_SYMBOL_GPL(nf_conntrack_max); 66 67DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 68EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 69 70unsigned int nf_conntrack_hash_rnd __read_mostly; 71EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd); 72 73static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 74{ 75 unsigned int n; 76 77 /* The direction must be ignored, so we hash everything up to the 78 * destination ports (which is a multiple of 4) and treat the last 79 * three bytes manually. 80 */ 81 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 82 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 83 (((__force __u16)tuple->dst.u.all << 16) | 84 tuple->dst.protonum)); 85} 86 87static u32 __hash_bucket(u32 hash, unsigned int size) 88{ 89 return ((u64)hash * size) >> 32; 90} 91 92static u32 hash_bucket(u32 hash, const struct net *net) 93{ 94 return __hash_bucket(hash, net->ct.htable_size); 95} 96 97static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 98 u16 zone, unsigned int size) 99{ 100 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 101} 102 103static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 104 const struct nf_conntrack_tuple *tuple) 105{ 106 return __hash_conntrack(tuple, zone, net->ct.htable_size); 107} 108 109bool 110nf_ct_get_tuple(const struct sk_buff *skb, 111 unsigned int nhoff, 112 unsigned int dataoff, 113 u_int16_t l3num, 114 u_int8_t protonum, 115 struct nf_conntrack_tuple *tuple, 116 const struct nf_conntrack_l3proto *l3proto, 117 const struct nf_conntrack_l4proto *l4proto) 118{ 119 memset(tuple, 0, sizeof(*tuple)); 120 121 tuple->src.l3num = l3num; 122 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 123 return false; 124 125 tuple->dst.protonum = protonum; 126 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 127 128 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 129} 130EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 131 132bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 133 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 134{ 135 struct nf_conntrack_l3proto *l3proto; 136 struct nf_conntrack_l4proto *l4proto; 137 unsigned int protoff; 138 u_int8_t protonum; 139 int ret; 140 141 rcu_read_lock(); 142 143 l3proto = __nf_ct_l3proto_find(l3num); 144 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 145 if (ret != NF_ACCEPT) { 146 rcu_read_unlock(); 147 return false; 148 } 149 150 l4proto = __nf_ct_l4proto_find(l3num, protonum); 151 152 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 153 l3proto, l4proto); 154 155 rcu_read_unlock(); 156 return ret; 157} 158EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 159 160bool 161nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 162 const struct nf_conntrack_tuple *orig, 163 const struct nf_conntrack_l3proto *l3proto, 164 const struct nf_conntrack_l4proto *l4proto) 165{ 166 memset(inverse, 0, sizeof(*inverse)); 167 168 inverse->src.l3num = orig->src.l3num; 169 if (l3proto->invert_tuple(inverse, orig) == 0) 170 return false; 171 172 inverse->dst.dir = !orig->dst.dir; 173 174 inverse->dst.protonum = orig->dst.protonum; 175 return l4proto->invert_tuple(inverse, orig); 176} 177EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 178 179static void 180clean_from_lists(struct nf_conn *ct) 181{ 182 pr_debug("clean_from_lists(%p)\n", ct); 183 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 184 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 185 186 /* Destroy all pending expectations */ 187 nf_ct_remove_expectations(ct); 188} 189 190static void 191destroy_conntrack(struct nf_conntrack *nfct) 192{ 193 struct nf_conn *ct = (struct nf_conn *)nfct; 194 struct net *net = nf_ct_net(ct); 195 struct nf_conntrack_l4proto *l4proto; 196 197 pr_debug("destroy_conntrack(%p)\n", ct); 198 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 199 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 200 201 /* To make sure we don't get any weird locking issues here: 202 * destroy_conntrack() MUST NOT be called with a write lock 203 * to nf_conntrack_lock!!! -HW */ 204 rcu_read_lock(); 205 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 206 if (l4proto && l4proto->destroy) 207 l4proto->destroy(ct); 208 209 rcu_read_unlock(); 210 211 spin_lock_bh(&nf_conntrack_lock); 212 /* Expectations will have been removed in clean_from_lists, 213 * except TFTP can create an expectation on the first packet, 214 * before connection is in the list, so we need to clean here, 215 * too. */ 216 nf_ct_remove_expectations(ct); 217 218 /* We overload first tuple to link into unconfirmed list. */ 219 if (!nf_ct_is_confirmed(ct)) { 220 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 221 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 222 } 223 224 NF_CT_STAT_INC(net, delete); 225 spin_unlock_bh(&nf_conntrack_lock); 226 227 if (ct->master) 228 nf_ct_put(ct->master); 229 230 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 231 nf_conntrack_free(ct); 232} 233 234void nf_ct_delete_from_lists(struct nf_conn *ct) 235{ 236 struct net *net = nf_ct_net(ct); 237 238 nf_ct_helper_destroy(ct); 239 spin_lock_bh(&nf_conntrack_lock); 240 /* Inside lock so preempt is disabled on module removal path. 241 * Otherwise we can get spurious warnings. */ 242 NF_CT_STAT_INC(net, delete_list); 243 clean_from_lists(ct); 244 spin_unlock_bh(&nf_conntrack_lock); 245} 246EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 247 248static void death_by_event(unsigned long ul_conntrack) 249{ 250 struct nf_conn *ct = (void *)ul_conntrack; 251 struct net *net = nf_ct_net(ct); 252 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 253 254 BUG_ON(ecache == NULL); 255 256 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 257 /* bad luck, let's retry again */ 258 ecache->timeout.expires = jiffies + 259 (random32() % net->ct.sysctl_events_retry_timeout); 260 add_timer(&ecache->timeout); 261 return; 262 } 263 /* we've got the event delivered, now it's dying */ 264 set_bit(IPS_DYING_BIT, &ct->status); 265 spin_lock(&nf_conntrack_lock); 266 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 267 spin_unlock(&nf_conntrack_lock); 268 nf_ct_put(ct); 269} 270 271void nf_ct_insert_dying_list(struct nf_conn *ct) 272{ 273 struct net *net = nf_ct_net(ct); 274 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 275 276 BUG_ON(ecache == NULL); 277 278 /* add this conntrack to the dying list */ 279 spin_lock_bh(&nf_conntrack_lock); 280 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 281 &net->ct.dying); 282 spin_unlock_bh(&nf_conntrack_lock); 283 /* set a new timer to retry event delivery */ 284 setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct); 285 ecache->timeout.expires = jiffies + 286 (random32() % net->ct.sysctl_events_retry_timeout); 287 add_timer(&ecache->timeout); 288} 289EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); 290 291static void death_by_timeout(unsigned long ul_conntrack) 292{ 293 struct nf_conn *ct = (void *)ul_conntrack; 294 struct nf_conn_tstamp *tstamp; 295 296 tstamp = nf_conn_tstamp_find(ct); 297 if (tstamp && tstamp->stop == 0) 298 tstamp->stop = ktime_to_ns(ktime_get_real()); 299 300 if (!test_bit(IPS_DYING_BIT, &ct->status) && 301 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 302 /* destroy event was not delivered */ 303 nf_ct_delete_from_lists(ct); 304 nf_ct_insert_dying_list(ct); 305 return; 306 } 307 set_bit(IPS_DYING_BIT, &ct->status); 308 nf_ct_delete_from_lists(ct); 309 nf_ct_put(ct); 310} 311 312/* 313 * Warning : 314 * - Caller must take a reference on returned object 315 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 316 * OR 317 * - Caller must lock nf_conntrack_lock before calling this function 318 */ 319static struct nf_conntrack_tuple_hash * 320____nf_conntrack_find(struct net *net, u16 zone, 321 const struct nf_conntrack_tuple *tuple, u32 hash) 322{ 323 struct nf_conntrack_tuple_hash *h; 324 struct hlist_nulls_node *n; 325 unsigned int bucket = hash_bucket(hash, net); 326 327 /* Disable BHs the entire time since we normally need to disable them 328 * at least once for the stats anyway. 329 */ 330 local_bh_disable(); 331begin: 332 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) { 333 if (nf_ct_tuple_equal(tuple, &h->tuple) && 334 nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { 335 NF_CT_STAT_INC(net, found); 336 local_bh_enable(); 337 return h; 338 } 339 NF_CT_STAT_INC(net, searched); 340 } 341 /* 342 * if the nulls value we got at the end of this lookup is 343 * not the expected one, we must restart lookup. 344 * We probably met an item that was moved to another chain. 345 */ 346 if (get_nulls_value(n) != bucket) { 347 NF_CT_STAT_INC(net, search_restart); 348 goto begin; 349 } 350 local_bh_enable(); 351 352 return NULL; 353} 354 355struct nf_conntrack_tuple_hash * 356__nf_conntrack_find(struct net *net, u16 zone, 357 const struct nf_conntrack_tuple *tuple) 358{ 359 return ____nf_conntrack_find(net, zone, tuple, 360 hash_conntrack_raw(tuple, zone)); 361} 362EXPORT_SYMBOL_GPL(__nf_conntrack_find); 363 364/* Find a connection corresponding to a tuple. */ 365static struct nf_conntrack_tuple_hash * 366__nf_conntrack_find_get(struct net *net, u16 zone, 367 const struct nf_conntrack_tuple *tuple, u32 hash) 368{ 369 struct nf_conntrack_tuple_hash *h; 370 struct nf_conn *ct; 371 372 rcu_read_lock(); 373begin: 374 h = ____nf_conntrack_find(net, zone, tuple, hash); 375 if (h) { 376 ct = nf_ct_tuplehash_to_ctrack(h); 377 if (unlikely(nf_ct_is_dying(ct) || 378 !atomic_inc_not_zero(&ct->ct_general.use))) 379 h = NULL; 380 else { 381 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || 382 nf_ct_zone(ct) != zone)) { 383 nf_ct_put(ct); 384 goto begin; 385 } 386 } 387 } 388 rcu_read_unlock(); 389 390 return h; 391} 392 393struct nf_conntrack_tuple_hash * 394nf_conntrack_find_get(struct net *net, u16 zone, 395 const struct nf_conntrack_tuple *tuple) 396{ 397 return __nf_conntrack_find_get(net, zone, tuple, 398 hash_conntrack_raw(tuple, zone)); 399} 400EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 401 402static void __nf_conntrack_hash_insert(struct nf_conn *ct, 403 unsigned int hash, 404 unsigned int repl_hash) 405{ 406 struct net *net = nf_ct_net(ct); 407 408 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 409 &net->ct.hash[hash]); 410 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 411 &net->ct.hash[repl_hash]); 412} 413 414int 415nf_conntrack_hash_check_insert(struct nf_conn *ct) 416{ 417 struct net *net = nf_ct_net(ct); 418 unsigned int hash, repl_hash; 419 struct nf_conntrack_tuple_hash *h; 420 struct hlist_nulls_node *n; 421 u16 zone; 422 423 zone = nf_ct_zone(ct); 424 hash = hash_conntrack(net, zone, 425 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 426 repl_hash = hash_conntrack(net, zone, 427 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 428 429 spin_lock_bh(&nf_conntrack_lock); 430 431 /* See if there's one in the list already, including reverse */ 432 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 433 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 434 &h->tuple) && 435 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 436 goto out; 437 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 438 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 439 &h->tuple) && 440 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 441 goto out; 442 443 add_timer(&ct->timeout); 444 nf_conntrack_get(&ct->ct_general); 445 __nf_conntrack_hash_insert(ct, hash, repl_hash); 446 NF_CT_STAT_INC(net, insert); 447 spin_unlock_bh(&nf_conntrack_lock); 448 449 return 0; 450 451out: 452 NF_CT_STAT_INC(net, insert_failed); 453 spin_unlock_bh(&nf_conntrack_lock); 454 return -EEXIST; 455} 456EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); 457 458/* Confirm a connection given skb; places it in hash table */ 459int 460__nf_conntrack_confirm(struct sk_buff *skb) 461{ 462 unsigned int hash, repl_hash; 463 struct nf_conntrack_tuple_hash *h; 464 struct nf_conn *ct; 465 struct nf_conn_help *help; 466 struct nf_conn_tstamp *tstamp; 467 struct hlist_nulls_node *n; 468 enum ip_conntrack_info ctinfo; 469 struct net *net; 470 u16 zone; 471 472 ct = nf_ct_get(skb, &ctinfo); 473 net = nf_ct_net(ct); 474 475 /* ipt_REJECT uses nf_conntrack_attach to attach related 476 ICMP/TCP RST packets in other direction. Actual packet 477 which created connection will be IP_CT_NEW or for an 478 expected connection, IP_CT_RELATED. */ 479 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 480 return NF_ACCEPT; 481 482 zone = nf_ct_zone(ct); 483 /* reuse the hash saved before */ 484 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 485 hash = hash_bucket(hash, net); 486 repl_hash = hash_conntrack(net, zone, 487 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 488 489 /* We're not in hash table, and we refuse to set up related 490 connections for unconfirmed conns. But packet copies and 491 REJECT will give spurious warnings here. */ 492 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 493 494 /* No external references means no one else could have 495 confirmed us. */ 496 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 497 pr_debug("Confirming conntrack %p\n", ct); 498 499 spin_lock_bh(&nf_conntrack_lock); 500 501 /* We have to check the DYING flag inside the lock to prevent 502 a race against nf_ct_get_next_corpse() possibly called from 503 user context, else we insert an already 'dead' hash, blocking 504 further use of that particular connection -JM */ 505 506 if (unlikely(nf_ct_is_dying(ct))) { 507 spin_unlock_bh(&nf_conntrack_lock); 508 return NF_ACCEPT; 509 } 510 511 /* See if there's one in the list already, including reverse: 512 NAT could have grabbed it without realizing, since we're 513 not in the hash. If there is, we lost race. */ 514 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 515 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 516 &h->tuple) && 517 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 518 goto out; 519 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 520 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 521 &h->tuple) && 522 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 523 goto out; 524 525 /* Remove from unconfirmed list */ 526 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 527 528 /* Timer relative to confirmation time, not original 529 setting time, otherwise we'd get timer wrap in 530 weird delay cases. */ 531 ct->timeout.expires += jiffies; 532 add_timer(&ct->timeout); 533 atomic_inc(&ct->ct_general.use); 534 ct->status |= IPS_CONFIRMED; 535 536 /* set conntrack timestamp, if enabled. */ 537 tstamp = nf_conn_tstamp_find(ct); 538 if (tstamp) { 539 if (skb->tstamp.tv64 == 0) 540 __net_timestamp(skb); 541 542 tstamp->start = ktime_to_ns(skb->tstamp); 543 } 544 /* Since the lookup is lockless, hash insertion must be done after 545 * starting the timer and setting the CONFIRMED bit. The RCU barriers 546 * guarantee that no other CPU can find the conntrack before the above 547 * stores are visible. 548 */ 549 __nf_conntrack_hash_insert(ct, hash, repl_hash); 550 NF_CT_STAT_INC(net, insert); 551 spin_unlock_bh(&nf_conntrack_lock); 552 553 help = nfct_help(ct); 554 if (help && help->helper) 555 nf_conntrack_event_cache(IPCT_HELPER, ct); 556 557 nf_conntrack_event_cache(master_ct(ct) ? 558 IPCT_RELATED : IPCT_NEW, ct); 559 return NF_ACCEPT; 560 561out: 562 NF_CT_STAT_INC(net, insert_failed); 563 spin_unlock_bh(&nf_conntrack_lock); 564 return NF_DROP; 565} 566EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 567 568/* Returns true if a connection correspondings to the tuple (required 569 for NAT). */ 570int 571nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 572 const struct nf_conn *ignored_conntrack) 573{ 574 struct net *net = nf_ct_net(ignored_conntrack); 575 struct nf_conntrack_tuple_hash *h; 576 struct hlist_nulls_node *n; 577 struct nf_conn *ct; 578 u16 zone = nf_ct_zone(ignored_conntrack); 579 unsigned int hash = hash_conntrack(net, zone, tuple); 580 581 /* Disable BHs the entire time since we need to disable them at 582 * least once for the stats anyway. 583 */ 584 rcu_read_lock_bh(); 585 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 586 ct = nf_ct_tuplehash_to_ctrack(h); 587 if (ct != ignored_conntrack && 588 nf_ct_tuple_equal(tuple, &h->tuple) && 589 nf_ct_zone(ct) == zone) { 590 NF_CT_STAT_INC(net, found); 591 rcu_read_unlock_bh(); 592 return 1; 593 } 594 NF_CT_STAT_INC(net, searched); 595 } 596 rcu_read_unlock_bh(); 597 598 return 0; 599} 600EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 601 602#define NF_CT_EVICTION_RANGE 8 603 604/* There's a small race here where we may free a just-assured 605 connection. Too bad: we're in trouble anyway. */ 606static noinline int early_drop(struct net *net, unsigned int hash) 607{ 608 /* Use oldest entry, which is roughly LRU */ 609 struct nf_conntrack_tuple_hash *h; 610 struct nf_conn *ct = NULL, *tmp; 611 struct hlist_nulls_node *n; 612 unsigned int i, cnt = 0; 613 int dropped = 0; 614 615 rcu_read_lock(); 616 for (i = 0; i < net->ct.htable_size; i++) { 617 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 618 hnnode) { 619 tmp = nf_ct_tuplehash_to_ctrack(h); 620 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 621 ct = tmp; 622 cnt++; 623 } 624 625 if (ct != NULL) { 626 if (likely(!nf_ct_is_dying(ct) && 627 atomic_inc_not_zero(&ct->ct_general.use))) 628 break; 629 else 630 ct = NULL; 631 } 632 633 if (cnt >= NF_CT_EVICTION_RANGE) 634 break; 635 636 hash = (hash + 1) % net->ct.htable_size; 637 } 638 rcu_read_unlock(); 639 640 if (!ct) 641 return dropped; 642 643 if (del_timer(&ct->timeout)) { 644 death_by_timeout((unsigned long)ct); 645 /* Check if we indeed killed this entry. Reliable event 646 delivery may have inserted it into the dying list. */ 647 if (test_bit(IPS_DYING_BIT, &ct->status)) { 648 dropped = 1; 649 NF_CT_STAT_INC_ATOMIC(net, early_drop); 650 } 651 } 652 nf_ct_put(ct); 653 return dropped; 654} 655 656void init_nf_conntrack_hash_rnd(void) 657{ 658 unsigned int rand; 659 660 /* 661 * Why not initialize nf_conntrack_rnd in a "init()" function ? 662 * Because there isn't enough entropy when system initializing, 663 * and we initialize it as late as possible. 664 */ 665 do { 666 get_random_bytes(&rand, sizeof(rand)); 667 } while (!rand); 668 cmpxchg(&nf_conntrack_hash_rnd, 0, rand); 669} 670 671static struct nf_conn * 672__nf_conntrack_alloc(struct net *net, u16 zone, 673 const struct nf_conntrack_tuple *orig, 674 const struct nf_conntrack_tuple *repl, 675 gfp_t gfp, u32 hash) 676{ 677 struct nf_conn *ct; 678 679 if (unlikely(!nf_conntrack_hash_rnd)) { 680 init_nf_conntrack_hash_rnd(); 681 /* recompute the hash as nf_conntrack_hash_rnd is initialized */ 682 hash = hash_conntrack_raw(orig, zone); 683 } 684 685 /* We don't want any race condition at early drop stage */ 686 atomic_inc(&net->ct.count); 687 688 if (nf_conntrack_max && 689 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 690 if (!early_drop(net, hash_bucket(hash, net))) { 691 atomic_dec(&net->ct.count); 692 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n"); 693 return ERR_PTR(-ENOMEM); 694 } 695 } 696 697 /* 698 * Do not use kmem_cache_zalloc(), as this cache uses 699 * SLAB_DESTROY_BY_RCU. 700 */ 701 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 702 if (ct == NULL) { 703 atomic_dec(&net->ct.count); 704 return ERR_PTR(-ENOMEM); 705 } 706 /* 707 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 708 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 709 */ 710 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 711 offsetof(struct nf_conn, proto) - 712 offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 713 spin_lock_init(&ct->lock); 714 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 715 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 716 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 717 /* save hash for reusing when confirming */ 718 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 719 /* Don't set timer yet: wait for confirmation */ 720 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 721 write_pnet(&ct->ct_net, net); 722#ifdef CONFIG_NF_CONNTRACK_ZONES 723 if (zone) { 724 struct nf_conntrack_zone *nf_ct_zone; 725 726 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); 727 if (!nf_ct_zone) 728 goto out_free; 729 nf_ct_zone->id = zone; 730 } 731#endif 732 /* 733 * changes to lookup keys must be done before setting refcnt to 1 734 */ 735 smp_wmb(); 736 atomic_set(&ct->ct_general.use, 1); 737 return ct; 738 739#ifdef CONFIG_NF_CONNTRACK_ZONES 740out_free: 741 atomic_dec(&net->ct.count); 742 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 743 return ERR_PTR(-ENOMEM); 744#endif 745} 746 747struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, 748 const struct nf_conntrack_tuple *orig, 749 const struct nf_conntrack_tuple *repl, 750 gfp_t gfp) 751{ 752 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 753} 754EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 755 756void nf_conntrack_free(struct nf_conn *ct) 757{ 758 struct net *net = nf_ct_net(ct); 759 760 nf_ct_ext_destroy(ct); 761 atomic_dec(&net->ct.count); 762 nf_ct_ext_free(ct); 763 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 764} 765EXPORT_SYMBOL_GPL(nf_conntrack_free); 766 767/* Allocate a new conntrack: we return -ENOMEM if classification 768 failed due to stress. Otherwise it really is unclassifiable. */ 769static struct nf_conntrack_tuple_hash * 770init_conntrack(struct net *net, struct nf_conn *tmpl, 771 const struct nf_conntrack_tuple *tuple, 772 struct nf_conntrack_l3proto *l3proto, 773 struct nf_conntrack_l4proto *l4proto, 774 struct sk_buff *skb, 775 unsigned int dataoff, u32 hash) 776{ 777 struct nf_conn *ct; 778 struct nf_conn_help *help; 779 struct nf_conntrack_tuple repl_tuple; 780 struct nf_conntrack_ecache *ecache; 781 struct nf_conntrack_expect *exp; 782 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 783 struct nf_conn_timeout *timeout_ext; 784 unsigned int *timeouts; 785 786 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 787 pr_debug("Can't invert tuple.\n"); 788 return NULL; 789 } 790 791 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 792 hash); 793 if (IS_ERR(ct)) 794 return (struct nf_conntrack_tuple_hash *)ct; 795 796 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; 797 if (timeout_ext) 798 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext); 799 else 800 timeouts = l4proto->get_timeouts(net); 801 802 if (!l4proto->new(ct, skb, dataoff, timeouts)) { 803 nf_conntrack_free(ct); 804 pr_debug("init conntrack: can't track with proto module\n"); 805 return NULL; 806 } 807 808 if (timeout_ext) 809 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC); 810 811 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 812 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 813 814 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 815 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 816 ecache ? ecache->expmask : 0, 817 GFP_ATOMIC); 818 819 spin_lock_bh(&nf_conntrack_lock); 820 exp = nf_ct_find_expectation(net, zone, tuple); 821 if (exp) { 822 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 823 ct, exp); 824 /* Welcome, Mr. Bond. We've been expecting you... */ 825 __set_bit(IPS_EXPECTED_BIT, &ct->status); 826 ct->master = exp->master; 827 if (exp->helper) { 828 help = nf_ct_helper_ext_add(ct, exp->helper, 829 GFP_ATOMIC); 830 if (help) 831 rcu_assign_pointer(help->helper, exp->helper); 832 } 833 834#ifdef CONFIG_NF_CONNTRACK_MARK 835 ct->mark = exp->master->mark; 836#endif 837#ifdef CONFIG_NF_CONNTRACK_SECMARK 838 ct->secmark = exp->master->secmark; 839#endif 840 nf_conntrack_get(&ct->master->ct_general); 841 NF_CT_STAT_INC(net, expect_new); 842 } else { 843 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 844 NF_CT_STAT_INC(net, new); 845 } 846 847 /* Overload tuple linked list to put us in unconfirmed list. */ 848 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 849 &net->ct.unconfirmed); 850 851 spin_unlock_bh(&nf_conntrack_lock); 852 853 if (exp) { 854 if (exp->expectfn) 855 exp->expectfn(ct, exp); 856 nf_ct_expect_put(exp); 857 } 858 859 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 860} 861 862/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 863static inline struct nf_conn * 864resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 865 struct sk_buff *skb, 866 unsigned int dataoff, 867 u_int16_t l3num, 868 u_int8_t protonum, 869 struct nf_conntrack_l3proto *l3proto, 870 struct nf_conntrack_l4proto *l4proto, 871 int *set_reply, 872 enum ip_conntrack_info *ctinfo) 873{ 874 struct nf_conntrack_tuple tuple; 875 struct nf_conntrack_tuple_hash *h; 876 struct nf_conn *ct; 877 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 878 u32 hash; 879 880 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 881 dataoff, l3num, protonum, &tuple, l3proto, 882 l4proto)) { 883 pr_debug("resolve_normal_ct: Can't get tuple\n"); 884 return NULL; 885 } 886 887 /* look for tuple match */ 888 hash = hash_conntrack_raw(&tuple, zone); 889 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 890 if (!h) { 891 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 892 skb, dataoff, hash); 893 if (!h) 894 return NULL; 895 if (IS_ERR(h)) 896 return (void *)h; 897 } 898 ct = nf_ct_tuplehash_to_ctrack(h); 899 900 /* It exists; we have (non-exclusive) reference. */ 901 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 902 *ctinfo = IP_CT_ESTABLISHED_REPLY; 903 /* Please set reply bit if this packet OK */ 904 *set_reply = 1; 905 } else { 906 /* Once we've had two way comms, always ESTABLISHED. */ 907 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 908 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 909 *ctinfo = IP_CT_ESTABLISHED; 910 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 911 pr_debug("nf_conntrack_in: related packet for %p\n", 912 ct); 913 *ctinfo = IP_CT_RELATED; 914 } else { 915 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 916 *ctinfo = IP_CT_NEW; 917 } 918 *set_reply = 0; 919 } 920 skb->nfct = &ct->ct_general; 921 skb->nfctinfo = *ctinfo; 922 return ct; 923} 924 925unsigned int 926nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 927 struct sk_buff *skb) 928{ 929 struct nf_conn *ct, *tmpl = NULL; 930 enum ip_conntrack_info ctinfo; 931 struct nf_conntrack_l3proto *l3proto; 932 struct nf_conntrack_l4proto *l4proto; 933 struct nf_conn_timeout *timeout_ext; 934 unsigned int *timeouts; 935 unsigned int dataoff; 936 u_int8_t protonum; 937 int set_reply = 0; 938 int ret; 939 940 if (skb->nfct) { 941 /* Previously seen (loopback or untracked)? Ignore. */ 942 tmpl = (struct nf_conn *)skb->nfct; 943 if (!nf_ct_is_template(tmpl)) { 944 NF_CT_STAT_INC_ATOMIC(net, ignore); 945 return NF_ACCEPT; 946 } 947 skb->nfct = NULL; 948 } 949 950 /* rcu_read_lock()ed by nf_hook_slow */ 951 l3proto = __nf_ct_l3proto_find(pf); 952 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 953 &dataoff, &protonum); 954 if (ret <= 0) { 955 pr_debug("not prepared to track yet or error occurred\n"); 956 NF_CT_STAT_INC_ATOMIC(net, error); 957 NF_CT_STAT_INC_ATOMIC(net, invalid); 958 ret = -ret; 959 goto out; 960 } 961 962 l4proto = __nf_ct_l4proto_find(pf, protonum); 963 964 /* It may be an special packet, error, unclean... 965 * inverse of the return code tells to the netfilter 966 * core what to do with the packet. */ 967 if (l4proto->error != NULL) { 968 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 969 pf, hooknum); 970 if (ret <= 0) { 971 NF_CT_STAT_INC_ATOMIC(net, error); 972 NF_CT_STAT_INC_ATOMIC(net, invalid); 973 ret = -ret; 974 goto out; 975 } 976 /* ICMP[v6] protocol trackers may assign one conntrack. */ 977 if (skb->nfct) 978 goto out; 979 } 980 981 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 982 l3proto, l4proto, &set_reply, &ctinfo); 983 if (!ct) { 984 /* Not valid part of a connection */ 985 NF_CT_STAT_INC_ATOMIC(net, invalid); 986 ret = NF_ACCEPT; 987 goto out; 988 } 989 990 if (IS_ERR(ct)) { 991 /* Too stressed to deal. */ 992 NF_CT_STAT_INC_ATOMIC(net, drop); 993 ret = NF_DROP; 994 goto out; 995 } 996 997 NF_CT_ASSERT(skb->nfct); 998 999 /* Decide what timeout policy we want to apply to this flow. */ 1000 timeout_ext = nf_ct_timeout_find(ct); 1001 if (timeout_ext) 1002 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext); 1003 else 1004 timeouts = l4proto->get_timeouts(net); 1005 1006 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts); 1007 if (ret <= 0) { 1008 /* Invalid: inverse of the return code tells 1009 * the netfilter core what to do */ 1010 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 1011 nf_conntrack_put(skb->nfct); 1012 skb->nfct = NULL; 1013 NF_CT_STAT_INC_ATOMIC(net, invalid); 1014 if (ret == -NF_DROP) 1015 NF_CT_STAT_INC_ATOMIC(net, drop); 1016 ret = -ret; 1017 goto out; 1018 } 1019 1020 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 1021 nf_conntrack_event_cache(IPCT_REPLY, ct); 1022out: 1023 if (tmpl) { 1024 /* Special case: we have to repeat this hook, assign the 1025 * template again to this packet. We assume that this packet 1026 * has no conntrack assigned. This is used by nf_ct_tcp. */ 1027 if (ret == NF_REPEAT) 1028 skb->nfct = (struct nf_conntrack *)tmpl; 1029 else 1030 nf_ct_put(tmpl); 1031 } 1032 1033 return ret; 1034} 1035EXPORT_SYMBOL_GPL(nf_conntrack_in); 1036 1037bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 1038 const struct nf_conntrack_tuple *orig) 1039{ 1040 bool ret; 1041 1042 rcu_read_lock(); 1043 ret = nf_ct_invert_tuple(inverse, orig, 1044 __nf_ct_l3proto_find(orig->src.l3num), 1045 __nf_ct_l4proto_find(orig->src.l3num, 1046 orig->dst.protonum)); 1047 rcu_read_unlock(); 1048 return ret; 1049} 1050EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 1051 1052/* Alter reply tuple (maybe alter helper). This is for NAT, and is 1053 implicitly racy: see __nf_conntrack_confirm */ 1054void nf_conntrack_alter_reply(struct nf_conn *ct, 1055 const struct nf_conntrack_tuple *newreply) 1056{ 1057 struct nf_conn_help *help = nfct_help(ct); 1058 1059 /* Should be unconfirmed, so not in hash table yet */ 1060 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 1061 1062 pr_debug("Altering reply tuple of %p to ", ct); 1063 nf_ct_dump_tuple(newreply); 1064 1065 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 1066 if (ct->master || (help && !hlist_empty(&help->expectations))) 1067 return; 1068 1069 rcu_read_lock(); 1070 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 1071 rcu_read_unlock(); 1072} 1073EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 1074 1075/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 1076void __nf_ct_refresh_acct(struct nf_conn *ct, 1077 enum ip_conntrack_info ctinfo, 1078 const struct sk_buff *skb, 1079 unsigned long extra_jiffies, 1080 int do_acct) 1081{ 1082 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 1083 NF_CT_ASSERT(skb); 1084 1085 /* Only update if this is not a fixed timeout */ 1086 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 1087 goto acct; 1088 1089 /* If not in hash table, timer will not be active yet */ 1090 if (!nf_ct_is_confirmed(ct)) { 1091 ct->timeout.expires = extra_jiffies; 1092 } else { 1093 unsigned long newtime = jiffies + extra_jiffies; 1094 1095 /* Only update the timeout if the new timeout is at least 1096 HZ jiffies from the old timeout. Need del_timer for race 1097 avoidance (may already be dying). */ 1098 if (newtime - ct->timeout.expires >= HZ) 1099 mod_timer_pending(&ct->timeout, newtime); 1100 } 1101 1102acct: 1103 if (do_acct) { 1104 struct nf_conn_counter *acct; 1105 1106 acct = nf_conn_acct_find(ct); 1107 if (acct) { 1108 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1109 atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes); 1110 } 1111 } 1112} 1113EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1114 1115bool __nf_ct_kill_acct(struct nf_conn *ct, 1116 enum ip_conntrack_info ctinfo, 1117 const struct sk_buff *skb, 1118 int do_acct) 1119{ 1120 if (do_acct) { 1121 struct nf_conn_counter *acct; 1122 1123 acct = nf_conn_acct_find(ct); 1124 if (acct) { 1125 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1126 atomic64_add(skb->len - skb_network_offset(skb), 1127 &acct[CTINFO2DIR(ctinfo)].bytes); 1128 } 1129 } 1130 1131 if (del_timer(&ct->timeout)) { 1132 ct->timeout.function((unsigned long)ct); 1133 return true; 1134 } 1135 return false; 1136} 1137EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1138 1139#ifdef CONFIG_NF_CONNTRACK_ZONES 1140static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1141 .len = sizeof(struct nf_conntrack_zone), 1142 .align = __alignof__(struct nf_conntrack_zone), 1143 .id = NF_CT_EXT_ZONE, 1144}; 1145#endif 1146 1147#if IS_ENABLED(CONFIG_NF_CT_NETLINK) 1148 1149#include <linux/netfilter/nfnetlink.h> 1150#include <linux/netfilter/nfnetlink_conntrack.h> 1151#include <linux/mutex.h> 1152 1153/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1154 * in ip_conntrack_core, since we don't want the protocols to autoload 1155 * or depend on ctnetlink */ 1156int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1157 const struct nf_conntrack_tuple *tuple) 1158{ 1159 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) || 1160 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port)) 1161 goto nla_put_failure; 1162 return 0; 1163 1164nla_put_failure: 1165 return -1; 1166} 1167EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1168 1169const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1170 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1171 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1172}; 1173EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1174 1175int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1176 struct nf_conntrack_tuple *t) 1177{ 1178 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1179 return -EINVAL; 1180 1181 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1182 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1183 1184 return 0; 1185} 1186EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1187 1188int nf_ct_port_nlattr_tuple_size(void) 1189{ 1190 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1191} 1192EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1193#endif 1194 1195/* Used by ipt_REJECT and ip6t_REJECT. */ 1196static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1197{ 1198 struct nf_conn *ct; 1199 enum ip_conntrack_info ctinfo; 1200 1201 /* This ICMP is in reverse direction to the packet which caused it */ 1202 ct = nf_ct_get(skb, &ctinfo); 1203 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1204 ctinfo = IP_CT_RELATED_REPLY; 1205 else 1206 ctinfo = IP_CT_RELATED; 1207 1208 /* Attach to new skbuff, and increment count */ 1209 nskb->nfct = &ct->ct_general; 1210 nskb->nfctinfo = ctinfo; 1211 nf_conntrack_get(nskb->nfct); 1212} 1213 1214/* Bring out ya dead! */ 1215static struct nf_conn * 1216get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1217 void *data, unsigned int *bucket) 1218{ 1219 struct nf_conntrack_tuple_hash *h; 1220 struct nf_conn *ct; 1221 struct hlist_nulls_node *n; 1222 1223 spin_lock_bh(&nf_conntrack_lock); 1224 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1225 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 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 1338static void nf_conntrack_cleanup_init_net(void) 1339{ 1340 while (untrack_refs() > 0) 1341 schedule(); 1342 1343#ifdef CONFIG_NF_CONNTRACK_ZONES 1344 nf_ct_extend_unregister(&nf_ct_zone_extend); 1345#endif 1346} 1347 1348static void nf_conntrack_cleanup_net(struct net *net) 1349{ 1350 i_see_dead_people: 1351 nf_ct_iterate_cleanup(net, kill_all, NULL); 1352 nf_ct_release_dying_list(net); 1353 if (atomic_read(&net->ct.count) != 0) { 1354 schedule(); 1355 goto i_see_dead_people; 1356 } 1357 1358 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1359 nf_conntrack_helper_fini(net); 1360 nf_conntrack_timeout_fini(net); 1361 nf_conntrack_ecache_fini(net); 1362 nf_conntrack_tstamp_fini(net); 1363 nf_conntrack_acct_fini(net); 1364 nf_conntrack_expect_fini(net); 1365 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1366 kfree(net->ct.slabname); 1367 free_percpu(net->ct.stat); 1368} 1369 1370/* Mishearing the voices in his head, our hero wonders how he's 1371 supposed to kill the mall. */ 1372void nf_conntrack_cleanup(struct net *net) 1373{ 1374 if (net_eq(net, &init_net)) 1375 RCU_INIT_POINTER(ip_ct_attach, NULL); 1376 1377 /* This makes sure all current packets have passed through 1378 netfilter framework. Roll on, two-stage module 1379 delete... */ 1380 synchronize_net(); 1381 nf_conntrack_proto_fini(net); 1382 nf_conntrack_cleanup_net(net); 1383 1384 if (net_eq(net, &init_net)) { 1385 RCU_INIT_POINTER(nf_ct_destroy, NULL); 1386 nf_conntrack_cleanup_init_net(); 1387 } 1388} 1389 1390void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 1391{ 1392 struct hlist_nulls_head *hash; 1393 unsigned int nr_slots, i; 1394 size_t sz; 1395 1396 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1397 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1398 sz = nr_slots * sizeof(struct hlist_nulls_head); 1399 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1400 get_order(sz)); 1401 if (!hash) { 1402 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1403 hash = vzalloc(sz); 1404 } 1405 1406 if (hash && nulls) 1407 for (i = 0; i < nr_slots; i++) 1408 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1409 1410 return hash; 1411} 1412EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1413 1414int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1415{ 1416 int i, bucket; 1417 unsigned int hashsize, old_size; 1418 struct hlist_nulls_head *hash, *old_hash; 1419 struct nf_conntrack_tuple_hash *h; 1420 struct nf_conn *ct; 1421 1422 if (current->nsproxy->net_ns != &init_net) 1423 return -EOPNOTSUPP; 1424 1425 /* On boot, we can set this without any fancy locking. */ 1426 if (!nf_conntrack_htable_size) 1427 return param_set_uint(val, kp); 1428 1429 hashsize = simple_strtoul(val, NULL, 0); 1430 if (!hashsize) 1431 return -EINVAL; 1432 1433 hash = nf_ct_alloc_hashtable(&hashsize, 1); 1434 if (!hash) 1435 return -ENOMEM; 1436 1437 /* Lookups in the old hash might happen in parallel, which means we 1438 * might get false negatives during connection lookup. New connections 1439 * created because of a false negative won't make it into the hash 1440 * though since that required taking the lock. 1441 */ 1442 spin_lock_bh(&nf_conntrack_lock); 1443 for (i = 0; i < init_net.ct.htable_size; i++) { 1444 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1445 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1446 struct nf_conntrack_tuple_hash, hnnode); 1447 ct = nf_ct_tuplehash_to_ctrack(h); 1448 hlist_nulls_del_rcu(&h->hnnode); 1449 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1450 hashsize); 1451 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1452 } 1453 } 1454 old_size = init_net.ct.htable_size; 1455 old_hash = init_net.ct.hash; 1456 1457 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1458 init_net.ct.hash = hash; 1459 spin_unlock_bh(&nf_conntrack_lock); 1460 1461 nf_ct_free_hashtable(old_hash, old_size); 1462 return 0; 1463} 1464EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1465 1466module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1467 &nf_conntrack_htable_size, 0600); 1468 1469void nf_ct_untracked_status_or(unsigned long bits) 1470{ 1471 int cpu; 1472 1473 for_each_possible_cpu(cpu) 1474 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1475} 1476EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1477 1478static int nf_conntrack_init_init_net(void) 1479{ 1480 int max_factor = 8; 1481 int ret, cpu; 1482 1483 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1484 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1485 if (!nf_conntrack_htable_size) { 1486 nf_conntrack_htable_size 1487 = (((totalram_pages << PAGE_SHIFT) / 16384) 1488 / sizeof(struct hlist_head)); 1489 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1490 nf_conntrack_htable_size = 16384; 1491 if (nf_conntrack_htable_size < 32) 1492 nf_conntrack_htable_size = 32; 1493 1494 /* Use a max. factor of four by default to get the same max as 1495 * with the old struct list_heads. When a table size is given 1496 * we use the old value of 8 to avoid reducing the max. 1497 * entries. */ 1498 max_factor = 4; 1499 } 1500 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1501 1502 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1503 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1504 nf_conntrack_max); 1505#ifdef CONFIG_NF_CONNTRACK_ZONES 1506 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1507 if (ret < 0) 1508 goto err_extend; 1509#endif 1510 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1511 for_each_possible_cpu(cpu) { 1512 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1513 write_pnet(&ct->ct_net, &init_net); 1514 atomic_set(&ct->ct_general.use, 1); 1515 } 1516 /* - and look it like as a confirmed connection */ 1517 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1518 return 0; 1519 1520#ifdef CONFIG_NF_CONNTRACK_ZONES 1521err_extend: 1522#endif 1523 return ret; 1524} 1525 1526/* 1527 * We need to use special "null" values, not used in hash table 1528 */ 1529#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1530#define DYING_NULLS_VAL ((1<<30)+1) 1531 1532static int nf_conntrack_init_net(struct net *net) 1533{ 1534 int ret; 1535 1536 atomic_set(&net->ct.count, 0); 1537 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1538 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1539 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1540 if (!net->ct.stat) { 1541 ret = -ENOMEM; 1542 goto err_stat; 1543 } 1544 1545 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1546 if (!net->ct.slabname) { 1547 ret = -ENOMEM; 1548 goto err_slabname; 1549 } 1550 1551 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1552 sizeof(struct nf_conn), 0, 1553 SLAB_DESTROY_BY_RCU, NULL); 1554 if (!net->ct.nf_conntrack_cachep) { 1555 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1556 ret = -ENOMEM; 1557 goto err_cache; 1558 } 1559 1560 net->ct.htable_size = nf_conntrack_htable_size; 1561 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1); 1562 if (!net->ct.hash) { 1563 ret = -ENOMEM; 1564 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1565 goto err_hash; 1566 } 1567 ret = nf_conntrack_expect_init(net); 1568 if (ret < 0) 1569 goto err_expect; 1570 ret = nf_conntrack_acct_init(net); 1571 if (ret < 0) 1572 goto err_acct; 1573 ret = nf_conntrack_tstamp_init(net); 1574 if (ret < 0) 1575 goto err_tstamp; 1576 ret = nf_conntrack_ecache_init(net); 1577 if (ret < 0) 1578 goto err_ecache; 1579 ret = nf_conntrack_timeout_init(net); 1580 if (ret < 0) 1581 goto err_timeout; 1582 ret = nf_conntrack_helper_init(net); 1583 if (ret < 0) 1584 goto err_helper; 1585 return 0; 1586err_helper: 1587 nf_conntrack_timeout_fini(net); 1588err_timeout: 1589 nf_conntrack_ecache_fini(net); 1590err_ecache: 1591 nf_conntrack_tstamp_fini(net); 1592err_tstamp: 1593 nf_conntrack_acct_fini(net); 1594err_acct: 1595 nf_conntrack_expect_fini(net); 1596err_expect: 1597 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1598err_hash: 1599 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1600err_cache: 1601 kfree(net->ct.slabname); 1602err_slabname: 1603 free_percpu(net->ct.stat); 1604err_stat: 1605 return ret; 1606} 1607 1608s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1609 enum ip_conntrack_dir dir, 1610 u32 seq); 1611EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1612 1613int nf_conntrack_init(struct net *net) 1614{ 1615 int ret; 1616 1617 if (net_eq(net, &init_net)) { 1618 ret = nf_conntrack_init_init_net(); 1619 if (ret < 0) 1620 goto out_init_net; 1621 } 1622 ret = nf_conntrack_proto_init(net); 1623 if (ret < 0) 1624 goto out_proto; 1625 ret = nf_conntrack_init_net(net); 1626 if (ret < 0) 1627 goto out_net; 1628 1629 if (net_eq(net, &init_net)) { 1630 /* For use by REJECT target */ 1631 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach); 1632 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack); 1633 1634 /* Howto get NAT offsets */ 1635 RCU_INIT_POINTER(nf_ct_nat_offset, NULL); 1636 } 1637 return 0; 1638 1639out_net: 1640 nf_conntrack_proto_fini(net); 1641out_proto: 1642 if (net_eq(net, &init_net)) 1643 nf_conntrack_cleanup_init_net(); 1644out_init_net: 1645 return ret; 1646} 1647