nf_conntrack_core.c revision 04dac0111da7e1d284952cd415162451ffaa094d
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 58int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb, 59 struct nf_conn *ct, 60 enum ip_conntrack_info ctinfo, 61 unsigned int protoff); 62EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook); 63 64DEFINE_SPINLOCK(nf_conntrack_lock); 65EXPORT_SYMBOL_GPL(nf_conntrack_lock); 66 67unsigned int nf_conntrack_htable_size __read_mostly; 68EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 69 70unsigned int nf_conntrack_max __read_mostly; 71EXPORT_SYMBOL_GPL(nf_conntrack_max); 72 73DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 74EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 75 76unsigned int nf_conntrack_hash_rnd __read_mostly; 77EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd); 78 79static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 80{ 81 unsigned int n; 82 83 /* The direction must be ignored, so we hash everything up to the 84 * destination ports (which is a multiple of 4) and treat the last 85 * three bytes manually. 86 */ 87 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 88 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 89 (((__force __u16)tuple->dst.u.all << 16) | 90 tuple->dst.protonum)); 91} 92 93static u32 __hash_bucket(u32 hash, unsigned int size) 94{ 95 return ((u64)hash * size) >> 32; 96} 97 98static u32 hash_bucket(u32 hash, const struct net *net) 99{ 100 return __hash_bucket(hash, net->ct.htable_size); 101} 102 103static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 104 u16 zone, unsigned int size) 105{ 106 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 107} 108 109static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 110 const struct nf_conntrack_tuple *tuple) 111{ 112 return __hash_conntrack(tuple, zone, net->ct.htable_size); 113} 114 115bool 116nf_ct_get_tuple(const struct sk_buff *skb, 117 unsigned int nhoff, 118 unsigned int dataoff, 119 u_int16_t l3num, 120 u_int8_t protonum, 121 struct nf_conntrack_tuple *tuple, 122 const struct nf_conntrack_l3proto *l3proto, 123 const struct nf_conntrack_l4proto *l4proto) 124{ 125 memset(tuple, 0, sizeof(*tuple)); 126 127 tuple->src.l3num = l3num; 128 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 129 return false; 130 131 tuple->dst.protonum = protonum; 132 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 133 134 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 135} 136EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 137 138bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 139 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 140{ 141 struct nf_conntrack_l3proto *l3proto; 142 struct nf_conntrack_l4proto *l4proto; 143 unsigned int protoff; 144 u_int8_t protonum; 145 int ret; 146 147 rcu_read_lock(); 148 149 l3proto = __nf_ct_l3proto_find(l3num); 150 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 151 if (ret != NF_ACCEPT) { 152 rcu_read_unlock(); 153 return false; 154 } 155 156 l4proto = __nf_ct_l4proto_find(l3num, protonum); 157 158 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 159 l3proto, l4proto); 160 161 rcu_read_unlock(); 162 return ret; 163} 164EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 165 166bool 167nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 168 const struct nf_conntrack_tuple *orig, 169 const struct nf_conntrack_l3proto *l3proto, 170 const struct nf_conntrack_l4proto *l4proto) 171{ 172 memset(inverse, 0, sizeof(*inverse)); 173 174 inverse->src.l3num = orig->src.l3num; 175 if (l3proto->invert_tuple(inverse, orig) == 0) 176 return false; 177 178 inverse->dst.dir = !orig->dst.dir; 179 180 inverse->dst.protonum = orig->dst.protonum; 181 return l4proto->invert_tuple(inverse, orig); 182} 183EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 184 185static void 186clean_from_lists(struct nf_conn *ct) 187{ 188 pr_debug("clean_from_lists(%p)\n", ct); 189 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 190 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 191 192 /* Destroy all pending expectations */ 193 nf_ct_remove_expectations(ct); 194} 195 196static void 197destroy_conntrack(struct nf_conntrack *nfct) 198{ 199 struct nf_conn *ct = (struct nf_conn *)nfct; 200 struct net *net = nf_ct_net(ct); 201 struct nf_conntrack_l4proto *l4proto; 202 203 pr_debug("destroy_conntrack(%p)\n", ct); 204 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 205 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 206 207 /* To make sure we don't get any weird locking issues here: 208 * destroy_conntrack() MUST NOT be called with a write lock 209 * to nf_conntrack_lock!!! -HW */ 210 rcu_read_lock(); 211 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 212 if (l4proto && l4proto->destroy) 213 l4proto->destroy(ct); 214 215 rcu_read_unlock(); 216 217 spin_lock_bh(&nf_conntrack_lock); 218 /* Expectations will have been removed in clean_from_lists, 219 * except TFTP can create an expectation on the first packet, 220 * before connection is in the list, so we need to clean here, 221 * too. */ 222 nf_ct_remove_expectations(ct); 223 224 /* We overload first tuple to link into unconfirmed or dying list.*/ 225 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 226 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 227 228 NF_CT_STAT_INC(net, delete); 229 spin_unlock_bh(&nf_conntrack_lock); 230 231 if (ct->master) 232 nf_ct_put(ct->master); 233 234 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 235 nf_conntrack_free(ct); 236} 237 238void nf_ct_delete_from_lists(struct nf_conn *ct) 239{ 240 struct net *net = nf_ct_net(ct); 241 242 nf_ct_helper_destroy(ct); 243 spin_lock_bh(&nf_conntrack_lock); 244 /* Inside lock so preempt is disabled on module removal path. 245 * Otherwise we can get spurious warnings. */ 246 NF_CT_STAT_INC(net, delete_list); 247 clean_from_lists(ct); 248 /* add this conntrack to the dying list */ 249 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 250 &net->ct.dying); 251 spin_unlock_bh(&nf_conntrack_lock); 252} 253EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 254 255static void death_by_event(unsigned long ul_conntrack) 256{ 257 struct nf_conn *ct = (void *)ul_conntrack; 258 struct net *net = nf_ct_net(ct); 259 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 260 261 BUG_ON(ecache == NULL); 262 263 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 264 /* bad luck, let's retry again */ 265 ecache->timeout.expires = jiffies + 266 (random32() % net->ct.sysctl_events_retry_timeout); 267 add_timer(&ecache->timeout); 268 return; 269 } 270 /* we've got the event delivered, now it's dying */ 271 set_bit(IPS_DYING_BIT, &ct->status); 272 nf_ct_put(ct); 273} 274 275void nf_ct_dying_timeout(struct nf_conn *ct) 276{ 277 struct net *net = nf_ct_net(ct); 278 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 279 280 BUG_ON(ecache == NULL); 281 282 /* set a new timer to retry event delivery */ 283 setup_timer(&ecache->timeout, death_by_event, (unsigned long)ct); 284 ecache->timeout.expires = jiffies + 285 (random32() % net->ct.sysctl_events_retry_timeout); 286 add_timer(&ecache->timeout); 287} 288EXPORT_SYMBOL_GPL(nf_ct_dying_timeout); 289 290static void death_by_timeout(unsigned long ul_conntrack) 291{ 292 struct nf_conn *ct = (void *)ul_conntrack; 293 struct nf_conn_tstamp *tstamp; 294 295 tstamp = nf_conn_tstamp_find(ct); 296 if (tstamp && tstamp->stop == 0) 297 tstamp->stop = ktime_to_ns(ktime_get_real()); 298 299 if (!test_bit(IPS_DYING_BIT, &ct->status) && 300 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 301 /* destroy event was not delivered */ 302 nf_ct_delete_from_lists(ct); 303 nf_ct_dying_timeout(ct); 304 return; 305 } 306 set_bit(IPS_DYING_BIT, &ct->status); 307 nf_ct_delete_from_lists(ct); 308 nf_ct_put(ct); 309} 310 311/* 312 * Warning : 313 * - Caller must take a reference on returned object 314 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 315 * OR 316 * - Caller must lock nf_conntrack_lock before calling this function 317 */ 318static struct nf_conntrack_tuple_hash * 319____nf_conntrack_find(struct net *net, u16 zone, 320 const struct nf_conntrack_tuple *tuple, u32 hash) 321{ 322 struct nf_conntrack_tuple_hash *h; 323 struct hlist_nulls_node *n; 324 unsigned int bucket = hash_bucket(hash, net); 325 326 /* Disable BHs the entire time since we normally need to disable them 327 * at least once for the stats anyway. 328 */ 329 local_bh_disable(); 330begin: 331 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) { 332 if (nf_ct_tuple_equal(tuple, &h->tuple) && 333 nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { 334 NF_CT_STAT_INC(net, found); 335 local_bh_enable(); 336 return h; 337 } 338 NF_CT_STAT_INC(net, searched); 339 } 340 /* 341 * if the nulls value we got at the end of this lookup is 342 * not the expected one, we must restart lookup. 343 * We probably met an item that was moved to another chain. 344 */ 345 if (get_nulls_value(n) != bucket) { 346 NF_CT_STAT_INC(net, search_restart); 347 goto begin; 348 } 349 local_bh_enable(); 350 351 return NULL; 352} 353 354struct nf_conntrack_tuple_hash * 355__nf_conntrack_find(struct net *net, u16 zone, 356 const struct nf_conntrack_tuple *tuple) 357{ 358 return ____nf_conntrack_find(net, zone, tuple, 359 hash_conntrack_raw(tuple, zone)); 360} 361EXPORT_SYMBOL_GPL(__nf_conntrack_find); 362 363/* Find a connection corresponding to a tuple. */ 364static struct nf_conntrack_tuple_hash * 365__nf_conntrack_find_get(struct net *net, u16 zone, 366 const struct nf_conntrack_tuple *tuple, u32 hash) 367{ 368 struct nf_conntrack_tuple_hash *h; 369 struct nf_conn *ct; 370 371 rcu_read_lock(); 372begin: 373 h = ____nf_conntrack_find(net, zone, tuple, hash); 374 if (h) { 375 ct = nf_ct_tuplehash_to_ctrack(h); 376 if (unlikely(nf_ct_is_dying(ct) || 377 !atomic_inc_not_zero(&ct->ct_general.use))) 378 h = NULL; 379 else { 380 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || 381 nf_ct_zone(ct) != zone)) { 382 nf_ct_put(ct); 383 goto begin; 384 } 385 } 386 } 387 rcu_read_unlock(); 388 389 return h; 390} 391 392struct nf_conntrack_tuple_hash * 393nf_conntrack_find_get(struct net *net, u16 zone, 394 const struct nf_conntrack_tuple *tuple) 395{ 396 return __nf_conntrack_find_get(net, zone, tuple, 397 hash_conntrack_raw(tuple, zone)); 398} 399EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 400 401static void __nf_conntrack_hash_insert(struct nf_conn *ct, 402 unsigned int hash, 403 unsigned int repl_hash) 404{ 405 struct net *net = nf_ct_net(ct); 406 407 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 408 &net->ct.hash[hash]); 409 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 410 &net->ct.hash[repl_hash]); 411} 412 413int 414nf_conntrack_hash_check_insert(struct nf_conn *ct) 415{ 416 struct net *net = nf_ct_net(ct); 417 unsigned int hash, repl_hash; 418 struct nf_conntrack_tuple_hash *h; 419 struct hlist_nulls_node *n; 420 u16 zone; 421 422 zone = nf_ct_zone(ct); 423 hash = hash_conntrack(net, zone, 424 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 425 repl_hash = hash_conntrack(net, zone, 426 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 427 428 spin_lock_bh(&nf_conntrack_lock); 429 430 /* See if there's one in the list already, including reverse */ 431 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 432 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 433 &h->tuple) && 434 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 435 goto out; 436 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 437 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 438 &h->tuple) && 439 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 440 goto out; 441 442 add_timer(&ct->timeout); 443 nf_conntrack_get(&ct->ct_general); 444 __nf_conntrack_hash_insert(ct, hash, repl_hash); 445 NF_CT_STAT_INC(net, insert); 446 spin_unlock_bh(&nf_conntrack_lock); 447 448 return 0; 449 450out: 451 NF_CT_STAT_INC(net, insert_failed); 452 spin_unlock_bh(&nf_conntrack_lock); 453 return -EEXIST; 454} 455EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); 456 457/* Confirm a connection given skb; places it in hash table */ 458int 459__nf_conntrack_confirm(struct sk_buff *skb) 460{ 461 unsigned int hash, repl_hash; 462 struct nf_conntrack_tuple_hash *h; 463 struct nf_conn *ct; 464 struct nf_conn_help *help; 465 struct nf_conn_tstamp *tstamp; 466 struct hlist_nulls_node *n; 467 enum ip_conntrack_info ctinfo; 468 struct net *net; 469 u16 zone; 470 471 ct = nf_ct_get(skb, &ctinfo); 472 net = nf_ct_net(ct); 473 474 /* ipt_REJECT uses nf_conntrack_attach to attach related 475 ICMP/TCP RST packets in other direction. Actual packet 476 which created connection will be IP_CT_NEW or for an 477 expected connection, IP_CT_RELATED. */ 478 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 479 return NF_ACCEPT; 480 481 zone = nf_ct_zone(ct); 482 /* reuse the hash saved before */ 483 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 484 hash = hash_bucket(hash, net); 485 repl_hash = hash_conntrack(net, zone, 486 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 487 488 /* We're not in hash table, and we refuse to set up related 489 connections for unconfirmed conns. But packet copies and 490 REJECT will give spurious warnings here. */ 491 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 492 493 /* No external references means no one else could have 494 confirmed us. */ 495 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 496 pr_debug("Confirming conntrack %p\n", ct); 497 498 spin_lock_bh(&nf_conntrack_lock); 499 500 /* We have to check the DYING flag inside the lock to prevent 501 a race against nf_ct_get_next_corpse() possibly called from 502 user context, else we insert an already 'dead' hash, blocking 503 further use of that particular connection -JM */ 504 505 if (unlikely(nf_ct_is_dying(ct))) { 506 spin_unlock_bh(&nf_conntrack_lock); 507 return NF_ACCEPT; 508 } 509 510 /* See if there's one in the list already, including reverse: 511 NAT could have grabbed it without realizing, since we're 512 not in the hash. If there is, we lost race. */ 513 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 514 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 515 &h->tuple) && 516 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 517 goto out; 518 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 519 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 520 &h->tuple) && 521 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 522 goto out; 523 524 /* Remove from unconfirmed list */ 525 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 526 527 /* Timer relative to confirmation time, not original 528 setting time, otherwise we'd get timer wrap in 529 weird delay cases. */ 530 ct->timeout.expires += jiffies; 531 add_timer(&ct->timeout); 532 atomic_inc(&ct->ct_general.use); 533 ct->status |= IPS_CONFIRMED; 534 535 /* set conntrack timestamp, if enabled. */ 536 tstamp = nf_conn_tstamp_find(ct); 537 if (tstamp) { 538 if (skb->tstamp.tv64 == 0) 539 __net_timestamp(skb); 540 541 tstamp->start = ktime_to_ns(skb->tstamp); 542 } 543 /* Since the lookup is lockless, hash insertion must be done after 544 * starting the timer and setting the CONFIRMED bit. The RCU barriers 545 * guarantee that no other CPU can find the conntrack before the above 546 * stores are visible. 547 */ 548 __nf_conntrack_hash_insert(ct, hash, repl_hash); 549 NF_CT_STAT_INC(net, insert); 550 spin_unlock_bh(&nf_conntrack_lock); 551 552 help = nfct_help(ct); 553 if (help && help->helper) 554 nf_conntrack_event_cache(IPCT_HELPER, ct); 555 556 nf_conntrack_event_cache(master_ct(ct) ? 557 IPCT_RELATED : IPCT_NEW, ct); 558 return NF_ACCEPT; 559 560out: 561 NF_CT_STAT_INC(net, insert_failed); 562 spin_unlock_bh(&nf_conntrack_lock); 563 return NF_DROP; 564} 565EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 566 567/* Returns true if a connection correspondings to the tuple (required 568 for NAT). */ 569int 570nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 571 const struct nf_conn *ignored_conntrack) 572{ 573 struct net *net = nf_ct_net(ignored_conntrack); 574 struct nf_conntrack_tuple_hash *h; 575 struct hlist_nulls_node *n; 576 struct nf_conn *ct; 577 u16 zone = nf_ct_zone(ignored_conntrack); 578 unsigned int hash = hash_conntrack(net, zone, tuple); 579 580 /* Disable BHs the entire time since we need to disable them at 581 * least once for the stats anyway. 582 */ 583 rcu_read_lock_bh(); 584 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 585 ct = nf_ct_tuplehash_to_ctrack(h); 586 if (ct != ignored_conntrack && 587 nf_ct_tuple_equal(tuple, &h->tuple) && 588 nf_ct_zone(ct) == zone) { 589 NF_CT_STAT_INC(net, found); 590 rcu_read_unlock_bh(); 591 return 1; 592 } 593 NF_CT_STAT_INC(net, searched); 594 } 595 rcu_read_unlock_bh(); 596 597 return 0; 598} 599EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 600 601#define NF_CT_EVICTION_RANGE 8 602 603/* There's a small race here where we may free a just-assured 604 connection. Too bad: we're in trouble anyway. */ 605static noinline int early_drop(struct net *net, unsigned int hash) 606{ 607 /* Use oldest entry, which is roughly LRU */ 608 struct nf_conntrack_tuple_hash *h; 609 struct nf_conn *ct = NULL, *tmp; 610 struct hlist_nulls_node *n; 611 unsigned int i, cnt = 0; 612 int dropped = 0; 613 614 rcu_read_lock(); 615 for (i = 0; i < net->ct.htable_size; i++) { 616 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 617 hnnode) { 618 tmp = nf_ct_tuplehash_to_ctrack(h); 619 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 620 ct = tmp; 621 cnt++; 622 } 623 624 if (ct != NULL) { 625 if (likely(!nf_ct_is_dying(ct) && 626 atomic_inc_not_zero(&ct->ct_general.use))) 627 break; 628 else 629 ct = NULL; 630 } 631 632 if (cnt >= NF_CT_EVICTION_RANGE) 633 break; 634 635 hash = (hash + 1) % net->ct.htable_size; 636 } 637 rcu_read_unlock(); 638 639 if (!ct) 640 return dropped; 641 642 if (del_timer(&ct->timeout)) { 643 death_by_timeout((unsigned long)ct); 644 /* Check if we indeed killed this entry. Reliable event 645 delivery may have inserted it into the dying list. */ 646 if (test_bit(IPS_DYING_BIT, &ct->status)) { 647 dropped = 1; 648 NF_CT_STAT_INC_ATOMIC(net, early_drop); 649 } 650 } 651 nf_ct_put(ct); 652 return dropped; 653} 654 655void init_nf_conntrack_hash_rnd(void) 656{ 657 unsigned int rand; 658 659 /* 660 * Why not initialize nf_conntrack_rnd in a "init()" function ? 661 * Because there isn't enough entropy when system initializing, 662 * and we initialize it as late as possible. 663 */ 664 do { 665 get_random_bytes(&rand, sizeof(rand)); 666 } while (!rand); 667 cmpxchg(&nf_conntrack_hash_rnd, 0, rand); 668} 669 670static struct nf_conn * 671__nf_conntrack_alloc(struct net *net, u16 zone, 672 const struct nf_conntrack_tuple *orig, 673 const struct nf_conntrack_tuple *repl, 674 gfp_t gfp, u32 hash) 675{ 676 struct nf_conn *ct; 677 678 if (unlikely(!nf_conntrack_hash_rnd)) { 679 init_nf_conntrack_hash_rnd(); 680 /* recompute the hash as nf_conntrack_hash_rnd is initialized */ 681 hash = hash_conntrack_raw(orig, zone); 682 } 683 684 /* We don't want any race condition at early drop stage */ 685 atomic_inc(&net->ct.count); 686 687 if (nf_conntrack_max && 688 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 689 if (!early_drop(net, hash_bucket(hash, net))) { 690 atomic_dec(&net->ct.count); 691 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n"); 692 return ERR_PTR(-ENOMEM); 693 } 694 } 695 696 /* 697 * Do not use kmem_cache_zalloc(), as this cache uses 698 * SLAB_DESTROY_BY_RCU. 699 */ 700 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 701 if (ct == NULL) { 702 atomic_dec(&net->ct.count); 703 return ERR_PTR(-ENOMEM); 704 } 705 /* 706 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 707 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 708 */ 709 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 710 offsetof(struct nf_conn, proto) - 711 offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 712 spin_lock_init(&ct->lock); 713 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 714 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 715 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 716 /* save hash for reusing when confirming */ 717 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 718 /* Don't set timer yet: wait for confirmation */ 719 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 720 write_pnet(&ct->ct_net, net); 721#ifdef CONFIG_NF_CONNTRACK_ZONES 722 if (zone) { 723 struct nf_conntrack_zone *nf_ct_zone; 724 725 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); 726 if (!nf_ct_zone) 727 goto out_free; 728 nf_ct_zone->id = zone; 729 } 730#endif 731 /* 732 * changes to lookup keys must be done before setting refcnt to 1 733 */ 734 smp_wmb(); 735 atomic_set(&ct->ct_general.use, 1); 736 return ct; 737 738#ifdef CONFIG_NF_CONNTRACK_ZONES 739out_free: 740 atomic_dec(&net->ct.count); 741 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 742 return ERR_PTR(-ENOMEM); 743#endif 744} 745 746struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, 747 const struct nf_conntrack_tuple *orig, 748 const struct nf_conntrack_tuple *repl, 749 gfp_t gfp) 750{ 751 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 752} 753EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 754 755void nf_conntrack_free(struct nf_conn *ct) 756{ 757 struct net *net = nf_ct_net(ct); 758 759 nf_ct_ext_destroy(ct); 760 atomic_dec(&net->ct.count); 761 nf_ct_ext_free(ct); 762 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 763} 764EXPORT_SYMBOL_GPL(nf_conntrack_free); 765 766/* Allocate a new conntrack: we return -ENOMEM if classification 767 failed due to stress. Otherwise it really is unclassifiable. */ 768static struct nf_conntrack_tuple_hash * 769init_conntrack(struct net *net, struct nf_conn *tmpl, 770 const struct nf_conntrack_tuple *tuple, 771 struct nf_conntrack_l3proto *l3proto, 772 struct nf_conntrack_l4proto *l4proto, 773 struct sk_buff *skb, 774 unsigned int dataoff, u32 hash) 775{ 776 struct nf_conn *ct; 777 struct nf_conn_help *help; 778 struct nf_conntrack_tuple repl_tuple; 779 struct nf_conntrack_ecache *ecache; 780 struct nf_conntrack_expect *exp; 781 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 782 struct nf_conn_timeout *timeout_ext; 783 unsigned int *timeouts; 784 785 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 786 pr_debug("Can't invert tuple.\n"); 787 return NULL; 788 } 789 790 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 791 hash); 792 if (IS_ERR(ct)) 793 return (struct nf_conntrack_tuple_hash *)ct; 794 795 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; 796 if (timeout_ext) 797 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext); 798 else 799 timeouts = l4proto->get_timeouts(net); 800 801 if (!l4proto->new(ct, skb, dataoff, timeouts)) { 802 nf_conntrack_free(ct); 803 pr_debug("init conntrack: can't track with proto module\n"); 804 return NULL; 805 } 806 807 if (timeout_ext) 808 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC); 809 810 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 811 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 812 813 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 814 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 815 ecache ? ecache->expmask : 0, 816 GFP_ATOMIC); 817 818 spin_lock_bh(&nf_conntrack_lock); 819 exp = nf_ct_find_expectation(net, zone, tuple); 820 if (exp) { 821 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 822 ct, exp); 823 /* Welcome, Mr. Bond. We've been expecting you... */ 824 __set_bit(IPS_EXPECTED_BIT, &ct->status); 825 ct->master = exp->master; 826 if (exp->helper) { 827 help = nf_ct_helper_ext_add(ct, exp->helper, 828 GFP_ATOMIC); 829 if (help) 830 rcu_assign_pointer(help->helper, exp->helper); 831 } 832 833#ifdef CONFIG_NF_CONNTRACK_MARK 834 ct->mark = exp->master->mark; 835#endif 836#ifdef CONFIG_NF_CONNTRACK_SECMARK 837 ct->secmark = exp->master->secmark; 838#endif 839 nf_conntrack_get(&ct->master->ct_general); 840 NF_CT_STAT_INC(net, expect_new); 841 } else { 842 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 843 NF_CT_STAT_INC(net, new); 844 } 845 846 /* Overload tuple linked list to put us in unconfirmed list. */ 847 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 848 &net->ct.unconfirmed); 849 850 spin_unlock_bh(&nf_conntrack_lock); 851 852 if (exp) { 853 if (exp->expectfn) 854 exp->expectfn(ct, exp); 855 nf_ct_expect_put(exp); 856 } 857 858 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 859} 860 861/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 862static inline struct nf_conn * 863resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 864 struct sk_buff *skb, 865 unsigned int dataoff, 866 u_int16_t l3num, 867 u_int8_t protonum, 868 struct nf_conntrack_l3proto *l3proto, 869 struct nf_conntrack_l4proto *l4proto, 870 int *set_reply, 871 enum ip_conntrack_info *ctinfo) 872{ 873 struct nf_conntrack_tuple tuple; 874 struct nf_conntrack_tuple_hash *h; 875 struct nf_conn *ct; 876 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 877 u32 hash; 878 879 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 880 dataoff, l3num, protonum, &tuple, l3proto, 881 l4proto)) { 882 pr_debug("resolve_normal_ct: Can't get tuple\n"); 883 return NULL; 884 } 885 886 /* look for tuple match */ 887 hash = hash_conntrack_raw(&tuple, zone); 888 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 889 if (!h) { 890 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 891 skb, dataoff, hash); 892 if (!h) 893 return NULL; 894 if (IS_ERR(h)) 895 return (void *)h; 896 } 897 ct = nf_ct_tuplehash_to_ctrack(h); 898 899 /* It exists; we have (non-exclusive) reference. */ 900 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 901 *ctinfo = IP_CT_ESTABLISHED_REPLY; 902 /* Please set reply bit if this packet OK */ 903 *set_reply = 1; 904 } else { 905 /* Once we've had two way comms, always ESTABLISHED. */ 906 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 907 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 908 *ctinfo = IP_CT_ESTABLISHED; 909 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 910 pr_debug("nf_conntrack_in: related packet for %p\n", 911 ct); 912 *ctinfo = IP_CT_RELATED; 913 } else { 914 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 915 *ctinfo = IP_CT_NEW; 916 } 917 *set_reply = 0; 918 } 919 skb->nfct = &ct->ct_general; 920 skb->nfctinfo = *ctinfo; 921 return ct; 922} 923 924unsigned int 925nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 926 struct sk_buff *skb) 927{ 928 struct nf_conn *ct, *tmpl = NULL; 929 enum ip_conntrack_info ctinfo; 930 struct nf_conntrack_l3proto *l3proto; 931 struct nf_conntrack_l4proto *l4proto; 932 unsigned int *timeouts; 933 unsigned int dataoff; 934 u_int8_t protonum; 935 int set_reply = 0; 936 int ret; 937 938 if (skb->nfct) { 939 /* Previously seen (loopback or untracked)? Ignore. */ 940 tmpl = (struct nf_conn *)skb->nfct; 941 if (!nf_ct_is_template(tmpl)) { 942 NF_CT_STAT_INC_ATOMIC(net, ignore); 943 return NF_ACCEPT; 944 } 945 skb->nfct = NULL; 946 } 947 948 /* rcu_read_lock()ed by nf_hook_slow */ 949 l3proto = __nf_ct_l3proto_find(pf); 950 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 951 &dataoff, &protonum); 952 if (ret <= 0) { 953 pr_debug("not prepared to track yet or error occurred\n"); 954 NF_CT_STAT_INC_ATOMIC(net, error); 955 NF_CT_STAT_INC_ATOMIC(net, invalid); 956 ret = -ret; 957 goto out; 958 } 959 960 l4proto = __nf_ct_l4proto_find(pf, protonum); 961 962 /* It may be an special packet, error, unclean... 963 * inverse of the return code tells to the netfilter 964 * core what to do with the packet. */ 965 if (l4proto->error != NULL) { 966 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 967 pf, hooknum); 968 if (ret <= 0) { 969 NF_CT_STAT_INC_ATOMIC(net, error); 970 NF_CT_STAT_INC_ATOMIC(net, invalid); 971 ret = -ret; 972 goto out; 973 } 974 /* ICMP[v6] protocol trackers may assign one conntrack. */ 975 if (skb->nfct) 976 goto out; 977 } 978 979 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 980 l3proto, l4proto, &set_reply, &ctinfo); 981 if (!ct) { 982 /* Not valid part of a connection */ 983 NF_CT_STAT_INC_ATOMIC(net, invalid); 984 ret = NF_ACCEPT; 985 goto out; 986 } 987 988 if (IS_ERR(ct)) { 989 /* Too stressed to deal. */ 990 NF_CT_STAT_INC_ATOMIC(net, drop); 991 ret = NF_DROP; 992 goto out; 993 } 994 995 NF_CT_ASSERT(skb->nfct); 996 997 /* Decide what timeout policy we want to apply to this flow. */ 998 timeouts = nf_ct_timeout_lookup(net, ct, l4proto); 999 1000 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts); 1001 if (ret <= 0) { 1002 /* Invalid: inverse of the return code tells 1003 * the netfilter core what to do */ 1004 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 1005 nf_conntrack_put(skb->nfct); 1006 skb->nfct = NULL; 1007 NF_CT_STAT_INC_ATOMIC(net, invalid); 1008 if (ret == -NF_DROP) 1009 NF_CT_STAT_INC_ATOMIC(net, drop); 1010 ret = -ret; 1011 goto out; 1012 } 1013 1014 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 1015 nf_conntrack_event_cache(IPCT_REPLY, ct); 1016out: 1017 if (tmpl) { 1018 /* Special case: we have to repeat this hook, assign the 1019 * template again to this packet. We assume that this packet 1020 * has no conntrack assigned. This is used by nf_ct_tcp. */ 1021 if (ret == NF_REPEAT) 1022 skb->nfct = (struct nf_conntrack *)tmpl; 1023 else 1024 nf_ct_put(tmpl); 1025 } 1026 1027 return ret; 1028} 1029EXPORT_SYMBOL_GPL(nf_conntrack_in); 1030 1031bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 1032 const struct nf_conntrack_tuple *orig) 1033{ 1034 bool ret; 1035 1036 rcu_read_lock(); 1037 ret = nf_ct_invert_tuple(inverse, orig, 1038 __nf_ct_l3proto_find(orig->src.l3num), 1039 __nf_ct_l4proto_find(orig->src.l3num, 1040 orig->dst.protonum)); 1041 rcu_read_unlock(); 1042 return ret; 1043} 1044EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 1045 1046/* Alter reply tuple (maybe alter helper). This is for NAT, and is 1047 implicitly racy: see __nf_conntrack_confirm */ 1048void nf_conntrack_alter_reply(struct nf_conn *ct, 1049 const struct nf_conntrack_tuple *newreply) 1050{ 1051 struct nf_conn_help *help = nfct_help(ct); 1052 1053 /* Should be unconfirmed, so not in hash table yet */ 1054 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 1055 1056 pr_debug("Altering reply tuple of %p to ", ct); 1057 nf_ct_dump_tuple(newreply); 1058 1059 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 1060 if (ct->master || (help && !hlist_empty(&help->expectations))) 1061 return; 1062 1063 rcu_read_lock(); 1064 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 1065 rcu_read_unlock(); 1066} 1067EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 1068 1069/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 1070void __nf_ct_refresh_acct(struct nf_conn *ct, 1071 enum ip_conntrack_info ctinfo, 1072 const struct sk_buff *skb, 1073 unsigned long extra_jiffies, 1074 int do_acct) 1075{ 1076 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 1077 NF_CT_ASSERT(skb); 1078 1079 /* Only update if this is not a fixed timeout */ 1080 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 1081 goto acct; 1082 1083 /* If not in hash table, timer will not be active yet */ 1084 if (!nf_ct_is_confirmed(ct)) { 1085 ct->timeout.expires = extra_jiffies; 1086 } else { 1087 unsigned long newtime = jiffies + extra_jiffies; 1088 1089 /* Only update the timeout if the new timeout is at least 1090 HZ jiffies from the old timeout. Need del_timer for race 1091 avoidance (may already be dying). */ 1092 if (newtime - ct->timeout.expires >= HZ) 1093 mod_timer_pending(&ct->timeout, newtime); 1094 } 1095 1096acct: 1097 if (do_acct) { 1098 struct nf_conn_counter *acct; 1099 1100 acct = nf_conn_acct_find(ct); 1101 if (acct) { 1102 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1103 atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes); 1104 } 1105 } 1106} 1107EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1108 1109bool __nf_ct_kill_acct(struct nf_conn *ct, 1110 enum ip_conntrack_info ctinfo, 1111 const struct sk_buff *skb, 1112 int do_acct) 1113{ 1114 if (do_acct) { 1115 struct nf_conn_counter *acct; 1116 1117 acct = nf_conn_acct_find(ct); 1118 if (acct) { 1119 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1120 atomic64_add(skb->len - skb_network_offset(skb), 1121 &acct[CTINFO2DIR(ctinfo)].bytes); 1122 } 1123 } 1124 1125 if (del_timer(&ct->timeout)) { 1126 ct->timeout.function((unsigned long)ct); 1127 return true; 1128 } 1129 return false; 1130} 1131EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1132 1133#ifdef CONFIG_NF_CONNTRACK_ZONES 1134static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1135 .len = sizeof(struct nf_conntrack_zone), 1136 .align = __alignof__(struct nf_conntrack_zone), 1137 .id = NF_CT_EXT_ZONE, 1138}; 1139#endif 1140 1141#if IS_ENABLED(CONFIG_NF_CT_NETLINK) 1142 1143#include <linux/netfilter/nfnetlink.h> 1144#include <linux/netfilter/nfnetlink_conntrack.h> 1145#include <linux/mutex.h> 1146 1147/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1148 * in ip_conntrack_core, since we don't want the protocols to autoload 1149 * or depend on ctnetlink */ 1150int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1151 const struct nf_conntrack_tuple *tuple) 1152{ 1153 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) || 1154 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port)) 1155 goto nla_put_failure; 1156 return 0; 1157 1158nla_put_failure: 1159 return -1; 1160} 1161EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1162 1163const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1164 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1165 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1166}; 1167EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1168 1169int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1170 struct nf_conntrack_tuple *t) 1171{ 1172 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1173 return -EINVAL; 1174 1175 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1176 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1177 1178 return 0; 1179} 1180EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1181 1182int nf_ct_port_nlattr_tuple_size(void) 1183{ 1184 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1185} 1186EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1187#endif 1188 1189/* Used by ipt_REJECT and ip6t_REJECT. */ 1190static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1191{ 1192 struct nf_conn *ct; 1193 enum ip_conntrack_info ctinfo; 1194 1195 /* This ICMP is in reverse direction to the packet which caused it */ 1196 ct = nf_ct_get(skb, &ctinfo); 1197 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1198 ctinfo = IP_CT_RELATED_REPLY; 1199 else 1200 ctinfo = IP_CT_RELATED; 1201 1202 /* Attach to new skbuff, and increment count */ 1203 nskb->nfct = &ct->ct_general; 1204 nskb->nfctinfo = ctinfo; 1205 nf_conntrack_get(nskb->nfct); 1206} 1207 1208/* Bring out ya dead! */ 1209static struct nf_conn * 1210get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1211 void *data, unsigned int *bucket) 1212{ 1213 struct nf_conntrack_tuple_hash *h; 1214 struct nf_conn *ct; 1215 struct hlist_nulls_node *n; 1216 1217 spin_lock_bh(&nf_conntrack_lock); 1218 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1219 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1220 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL) 1221 continue; 1222 ct = nf_ct_tuplehash_to_ctrack(h); 1223 if (iter(ct, data)) 1224 goto found; 1225 } 1226 } 1227 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1228 ct = nf_ct_tuplehash_to_ctrack(h); 1229 if (iter(ct, data)) 1230 set_bit(IPS_DYING_BIT, &ct->status); 1231 } 1232 spin_unlock_bh(&nf_conntrack_lock); 1233 return NULL; 1234found: 1235 atomic_inc(&ct->ct_general.use); 1236 spin_unlock_bh(&nf_conntrack_lock); 1237 return ct; 1238} 1239 1240void nf_ct_iterate_cleanup(struct net *net, 1241 int (*iter)(struct nf_conn *i, void *data), 1242 void *data) 1243{ 1244 struct nf_conn *ct; 1245 unsigned int bucket = 0; 1246 1247 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1248 /* Time to push up daises... */ 1249 if (del_timer(&ct->timeout)) 1250 death_by_timeout((unsigned long)ct); 1251 /* ... else the timer will get him soon. */ 1252 1253 nf_ct_put(ct); 1254 } 1255} 1256EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1257 1258struct __nf_ct_flush_report { 1259 u32 pid; 1260 int report; 1261}; 1262 1263static int kill_report(struct nf_conn *i, void *data) 1264{ 1265 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1266 struct nf_conn_tstamp *tstamp; 1267 1268 tstamp = nf_conn_tstamp_find(i); 1269 if (tstamp && tstamp->stop == 0) 1270 tstamp->stop = ktime_to_ns(ktime_get_real()); 1271 1272 /* If we fail to deliver the event, death_by_timeout() will retry */ 1273 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1274 fr->pid, fr->report) < 0) 1275 return 1; 1276 1277 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1278 set_bit(IPS_DYING_BIT, &i->status); 1279 return 1; 1280} 1281 1282static int kill_all(struct nf_conn *i, void *data) 1283{ 1284 return 1; 1285} 1286 1287void nf_ct_free_hashtable(void *hash, unsigned int size) 1288{ 1289 if (is_vmalloc_addr(hash)) 1290 vfree(hash); 1291 else 1292 free_pages((unsigned long)hash, 1293 get_order(sizeof(struct hlist_head) * size)); 1294} 1295EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1296 1297void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1298{ 1299 struct __nf_ct_flush_report fr = { 1300 .pid = pid, 1301 .report = report, 1302 }; 1303 nf_ct_iterate_cleanup(net, kill_report, &fr); 1304} 1305EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1306 1307static void nf_ct_release_dying_list(struct net *net) 1308{ 1309 struct nf_conntrack_tuple_hash *h; 1310 struct nf_conn *ct; 1311 struct hlist_nulls_node *n; 1312 1313 spin_lock_bh(&nf_conntrack_lock); 1314 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1315 ct = nf_ct_tuplehash_to_ctrack(h); 1316 /* never fails to remove them, no listeners at this point */ 1317 nf_ct_kill(ct); 1318 } 1319 spin_unlock_bh(&nf_conntrack_lock); 1320} 1321 1322static int untrack_refs(void) 1323{ 1324 int cnt = 0, cpu; 1325 1326 for_each_possible_cpu(cpu) { 1327 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1328 1329 cnt += atomic_read(&ct->ct_general.use) - 1; 1330 } 1331 return cnt; 1332} 1333 1334static void nf_conntrack_cleanup_init_net(void) 1335{ 1336 while (untrack_refs() > 0) 1337 schedule(); 1338 1339#ifdef CONFIG_NF_CONNTRACK_ZONES 1340 nf_ct_extend_unregister(&nf_ct_zone_extend); 1341#endif 1342} 1343 1344static void nf_conntrack_cleanup_net(struct net *net) 1345{ 1346 i_see_dead_people: 1347 nf_ct_iterate_cleanup(net, kill_all, NULL); 1348 nf_ct_release_dying_list(net); 1349 if (atomic_read(&net->ct.count) != 0) { 1350 schedule(); 1351 goto i_see_dead_people; 1352 } 1353 1354 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1355 nf_conntrack_helper_fini(net); 1356 nf_conntrack_timeout_fini(net); 1357 nf_conntrack_ecache_fini(net); 1358 nf_conntrack_tstamp_fini(net); 1359 nf_conntrack_acct_fini(net); 1360 nf_conntrack_expect_fini(net); 1361 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1362 kfree(net->ct.slabname); 1363 free_percpu(net->ct.stat); 1364} 1365 1366/* Mishearing the voices in his head, our hero wonders how he's 1367 supposed to kill the mall. */ 1368void nf_conntrack_cleanup(struct net *net) 1369{ 1370 if (net_eq(net, &init_net)) 1371 RCU_INIT_POINTER(ip_ct_attach, NULL); 1372 1373 /* This makes sure all current packets have passed through 1374 netfilter framework. Roll on, two-stage module 1375 delete... */ 1376 synchronize_net(); 1377 nf_conntrack_proto_fini(net); 1378 nf_conntrack_cleanup_net(net); 1379 1380 if (net_eq(net, &init_net)) { 1381 RCU_INIT_POINTER(nf_ct_destroy, NULL); 1382 nf_conntrack_cleanup_init_net(); 1383 } 1384} 1385 1386void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 1387{ 1388 struct hlist_nulls_head *hash; 1389 unsigned int nr_slots, i; 1390 size_t sz; 1391 1392 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1393 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1394 sz = nr_slots * sizeof(struct hlist_nulls_head); 1395 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1396 get_order(sz)); 1397 if (!hash) { 1398 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1399 hash = vzalloc(sz); 1400 } 1401 1402 if (hash && nulls) 1403 for (i = 0; i < nr_slots; i++) 1404 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1405 1406 return hash; 1407} 1408EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1409 1410int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1411{ 1412 int i, bucket; 1413 unsigned int hashsize, old_size; 1414 struct hlist_nulls_head *hash, *old_hash; 1415 struct nf_conntrack_tuple_hash *h; 1416 struct nf_conn *ct; 1417 1418 if (current->nsproxy->net_ns != &init_net) 1419 return -EOPNOTSUPP; 1420 1421 /* On boot, we can set this without any fancy locking. */ 1422 if (!nf_conntrack_htable_size) 1423 return param_set_uint(val, kp); 1424 1425 hashsize = simple_strtoul(val, NULL, 0); 1426 if (!hashsize) 1427 return -EINVAL; 1428 1429 hash = nf_ct_alloc_hashtable(&hashsize, 1); 1430 if (!hash) 1431 return -ENOMEM; 1432 1433 /* Lookups in the old hash might happen in parallel, which means we 1434 * might get false negatives during connection lookup. New connections 1435 * created because of a false negative won't make it into the hash 1436 * though since that required taking the lock. 1437 */ 1438 spin_lock_bh(&nf_conntrack_lock); 1439 for (i = 0; i < init_net.ct.htable_size; i++) { 1440 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1441 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1442 struct nf_conntrack_tuple_hash, hnnode); 1443 ct = nf_ct_tuplehash_to_ctrack(h); 1444 hlist_nulls_del_rcu(&h->hnnode); 1445 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1446 hashsize); 1447 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1448 } 1449 } 1450 old_size = init_net.ct.htable_size; 1451 old_hash = init_net.ct.hash; 1452 1453 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1454 init_net.ct.hash = hash; 1455 spin_unlock_bh(&nf_conntrack_lock); 1456 1457 nf_ct_free_hashtable(old_hash, old_size); 1458 return 0; 1459} 1460EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1461 1462module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1463 &nf_conntrack_htable_size, 0600); 1464 1465void nf_ct_untracked_status_or(unsigned long bits) 1466{ 1467 int cpu; 1468 1469 for_each_possible_cpu(cpu) 1470 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1471} 1472EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1473 1474static int nf_conntrack_init_init_net(void) 1475{ 1476 int max_factor = 8; 1477 int ret, cpu; 1478 1479 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1480 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1481 if (!nf_conntrack_htable_size) { 1482 nf_conntrack_htable_size 1483 = (((totalram_pages << PAGE_SHIFT) / 16384) 1484 / sizeof(struct hlist_head)); 1485 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1486 nf_conntrack_htable_size = 16384; 1487 if (nf_conntrack_htable_size < 32) 1488 nf_conntrack_htable_size = 32; 1489 1490 /* Use a max. factor of four by default to get the same max as 1491 * with the old struct list_heads. When a table size is given 1492 * we use the old value of 8 to avoid reducing the max. 1493 * entries. */ 1494 max_factor = 4; 1495 } 1496 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1497 1498 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1499 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1500 nf_conntrack_max); 1501#ifdef CONFIG_NF_CONNTRACK_ZONES 1502 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1503 if (ret < 0) 1504 goto err_extend; 1505#endif 1506 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1507 for_each_possible_cpu(cpu) { 1508 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1509 write_pnet(&ct->ct_net, &init_net); 1510 atomic_set(&ct->ct_general.use, 1); 1511 } 1512 /* - and look it like as a confirmed connection */ 1513 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1514 return 0; 1515 1516#ifdef CONFIG_NF_CONNTRACK_ZONES 1517err_extend: 1518#endif 1519 return ret; 1520} 1521 1522/* 1523 * We need to use special "null" values, not used in hash table 1524 */ 1525#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1526#define DYING_NULLS_VAL ((1<<30)+1) 1527 1528static int nf_conntrack_init_net(struct net *net) 1529{ 1530 int ret; 1531 1532 atomic_set(&net->ct.count, 0); 1533 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1534 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1535 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1536 if (!net->ct.stat) { 1537 ret = -ENOMEM; 1538 goto err_stat; 1539 } 1540 1541 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1542 if (!net->ct.slabname) { 1543 ret = -ENOMEM; 1544 goto err_slabname; 1545 } 1546 1547 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1548 sizeof(struct nf_conn), 0, 1549 SLAB_DESTROY_BY_RCU, NULL); 1550 if (!net->ct.nf_conntrack_cachep) { 1551 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1552 ret = -ENOMEM; 1553 goto err_cache; 1554 } 1555 1556 net->ct.htable_size = nf_conntrack_htable_size; 1557 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1); 1558 if (!net->ct.hash) { 1559 ret = -ENOMEM; 1560 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1561 goto err_hash; 1562 } 1563 ret = nf_conntrack_expect_init(net); 1564 if (ret < 0) 1565 goto err_expect; 1566 ret = nf_conntrack_acct_init(net); 1567 if (ret < 0) 1568 goto err_acct; 1569 ret = nf_conntrack_tstamp_init(net); 1570 if (ret < 0) 1571 goto err_tstamp; 1572 ret = nf_conntrack_ecache_init(net); 1573 if (ret < 0) 1574 goto err_ecache; 1575 ret = nf_conntrack_timeout_init(net); 1576 if (ret < 0) 1577 goto err_timeout; 1578 ret = nf_conntrack_helper_init(net); 1579 if (ret < 0) 1580 goto err_helper; 1581 return 0; 1582err_helper: 1583 nf_conntrack_timeout_fini(net); 1584err_timeout: 1585 nf_conntrack_ecache_fini(net); 1586err_ecache: 1587 nf_conntrack_tstamp_fini(net); 1588err_tstamp: 1589 nf_conntrack_acct_fini(net); 1590err_acct: 1591 nf_conntrack_expect_fini(net); 1592err_expect: 1593 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1594err_hash: 1595 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1596err_cache: 1597 kfree(net->ct.slabname); 1598err_slabname: 1599 free_percpu(net->ct.stat); 1600err_stat: 1601 return ret; 1602} 1603 1604s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1605 enum ip_conntrack_dir dir, 1606 u32 seq); 1607EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1608 1609int nf_conntrack_init(struct net *net) 1610{ 1611 int ret; 1612 1613 if (net_eq(net, &init_net)) { 1614 ret = nf_conntrack_init_init_net(); 1615 if (ret < 0) 1616 goto out_init_net; 1617 } 1618 ret = nf_conntrack_proto_init(net); 1619 if (ret < 0) 1620 goto out_proto; 1621 ret = nf_conntrack_init_net(net); 1622 if (ret < 0) 1623 goto out_net; 1624 1625 if (net_eq(net, &init_net)) { 1626 /* For use by REJECT target */ 1627 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach); 1628 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack); 1629 1630 /* Howto get NAT offsets */ 1631 RCU_INIT_POINTER(nf_ct_nat_offset, NULL); 1632 } 1633 return 0; 1634 1635out_net: 1636 nf_conntrack_proto_fini(net); 1637out_proto: 1638 if (net_eq(net, &init_net)) 1639 nf_conntrack_cleanup_init_net(); 1640out_init_net: 1641 return ret; 1642} 1643