nf_conntrack_core.c revision 8684094cf17d8ce96e0a8c63003f331aa017e22d
1/* Connection state tracking for netfilter. This is separated from, 2 but required by, the NAT layer; it can also be used by an iptables 3 extension. */ 4 5/* (C) 1999-2001 Paul `Rusty' Russell 6 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> 7 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14#include <linux/types.h> 15#include <linux/netfilter.h> 16#include <linux/module.h> 17#include <linux/sched.h> 18#include <linux/skbuff.h> 19#include <linux/proc_fs.h> 20#include <linux/vmalloc.h> 21#include <linux/stddef.h> 22#include <linux/slab.h> 23#include <linux/random.h> 24#include <linux/jhash.h> 25#include <linux/err.h> 26#include <linux/percpu.h> 27#include <linux/moduleparam.h> 28#include <linux/notifier.h> 29#include <linux/kernel.h> 30#include <linux/netdevice.h> 31#include <linux/socket.h> 32#include <linux/mm.h> 33#include <linux/nsproxy.h> 34#include <linux/rculist_nulls.h> 35 36#include <net/netfilter/nf_conntrack.h> 37#include <net/netfilter/nf_conntrack_l3proto.h> 38#include <net/netfilter/nf_conntrack_l4proto.h> 39#include <net/netfilter/nf_conntrack_expect.h> 40#include <net/netfilter/nf_conntrack_helper.h> 41#include <net/netfilter/nf_conntrack_core.h> 42#include <net/netfilter/nf_conntrack_extend.h> 43#include <net/netfilter/nf_conntrack_acct.h> 44#include <net/netfilter/nf_conntrack_ecache.h> 45#include <net/netfilter/nf_conntrack_zones.h> 46#include <net/netfilter/nf_conntrack_timestamp.h> 47#include <net/netfilter/nf_conntrack_timeout.h> 48#include <net/netfilter/nf_conntrack_labels.h> 49#include <net/netfilter/nf_nat.h> 50#include <net/netfilter/nf_nat_core.h> 51 52#define NF_CONNTRACK_VERSION "0.5.0" 53 54int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 55 enum nf_nat_manip_type manip, 56 const struct nlattr *attr) __read_mostly; 57EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 58 59int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb, 60 struct nf_conn *ct, 61 enum ip_conntrack_info ctinfo, 62 unsigned int protoff); 63EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook); 64 65DEFINE_SPINLOCK(nf_conntrack_lock); 66EXPORT_SYMBOL_GPL(nf_conntrack_lock); 67 68unsigned int nf_conntrack_htable_size __read_mostly; 69EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 70 71unsigned int nf_conntrack_max __read_mostly; 72EXPORT_SYMBOL_GPL(nf_conntrack_max); 73 74DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 75EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 76 77unsigned int nf_conntrack_hash_rnd __read_mostly; 78EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd); 79 80static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 81{ 82 unsigned int n; 83 84 /* The direction must be ignored, so we hash everything up to the 85 * destination ports (which is a multiple of 4) and treat the last 86 * three bytes manually. 87 */ 88 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 89 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 90 (((__force __u16)tuple->dst.u.all << 16) | 91 tuple->dst.protonum)); 92} 93 94static u32 __hash_bucket(u32 hash, unsigned int size) 95{ 96 return ((u64)hash * size) >> 32; 97} 98 99static u32 hash_bucket(u32 hash, const struct net *net) 100{ 101 return __hash_bucket(hash, net->ct.htable_size); 102} 103 104static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 105 u16 zone, unsigned int size) 106{ 107 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 108} 109 110static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 111 const struct nf_conntrack_tuple *tuple) 112{ 113 return __hash_conntrack(tuple, zone, net->ct.htable_size); 114} 115 116bool 117nf_ct_get_tuple(const struct sk_buff *skb, 118 unsigned int nhoff, 119 unsigned int dataoff, 120 u_int16_t l3num, 121 u_int8_t protonum, 122 struct nf_conntrack_tuple *tuple, 123 const struct nf_conntrack_l3proto *l3proto, 124 const struct nf_conntrack_l4proto *l4proto) 125{ 126 memset(tuple, 0, sizeof(*tuple)); 127 128 tuple->src.l3num = l3num; 129 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 130 return false; 131 132 tuple->dst.protonum = protonum; 133 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 134 135 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 136} 137EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 138 139bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 140 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 141{ 142 struct nf_conntrack_l3proto *l3proto; 143 struct nf_conntrack_l4proto *l4proto; 144 unsigned int protoff; 145 u_int8_t protonum; 146 int ret; 147 148 rcu_read_lock(); 149 150 l3proto = __nf_ct_l3proto_find(l3num); 151 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 152 if (ret != NF_ACCEPT) { 153 rcu_read_unlock(); 154 return false; 155 } 156 157 l4proto = __nf_ct_l4proto_find(l3num, protonum); 158 159 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 160 l3proto, l4proto); 161 162 rcu_read_unlock(); 163 return ret; 164} 165EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 166 167bool 168nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 169 const struct nf_conntrack_tuple *orig, 170 const struct nf_conntrack_l3proto *l3proto, 171 const struct nf_conntrack_l4proto *l4proto) 172{ 173 memset(inverse, 0, sizeof(*inverse)); 174 175 inverse->src.l3num = orig->src.l3num; 176 if (l3proto->invert_tuple(inverse, orig) == 0) 177 return false; 178 179 inverse->dst.dir = !orig->dst.dir; 180 181 inverse->dst.protonum = orig->dst.protonum; 182 return l4proto->invert_tuple(inverse, orig); 183} 184EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 185 186static void 187clean_from_lists(struct nf_conn *ct) 188{ 189 pr_debug("clean_from_lists(%p)\n", ct); 190 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 191 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 192 193 /* Destroy all pending expectations */ 194 nf_ct_remove_expectations(ct); 195} 196 197static void 198destroy_conntrack(struct nf_conntrack *nfct) 199{ 200 struct nf_conn *ct = (struct nf_conn *)nfct; 201 struct net *net = nf_ct_net(ct); 202 struct nf_conntrack_l4proto *l4proto; 203 204 pr_debug("destroy_conntrack(%p)\n", ct); 205 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 206 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 207 208 /* To make sure we don't get any weird locking issues here: 209 * destroy_conntrack() MUST NOT be called with a write lock 210 * to nf_conntrack_lock!!! -HW */ 211 rcu_read_lock(); 212 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 213 if (l4proto && l4proto->destroy) 214 l4proto->destroy(ct); 215 216 rcu_read_unlock(); 217 218 spin_lock_bh(&nf_conntrack_lock); 219 /* Expectations will have been removed in clean_from_lists, 220 * except TFTP can create an expectation on the first packet, 221 * before connection is in the list, so we need to clean here, 222 * too. */ 223 nf_ct_remove_expectations(ct); 224 225 /* We overload first tuple to link into unconfirmed or dying list.*/ 226 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 227 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 228 229 NF_CT_STAT_INC(net, delete); 230 spin_unlock_bh(&nf_conntrack_lock); 231 232 if (ct->master) 233 nf_ct_put(ct->master); 234 235 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 236 nf_conntrack_free(ct); 237} 238 239void nf_ct_delete_from_lists(struct nf_conn *ct) 240{ 241 struct net *net = nf_ct_net(ct); 242 243 nf_ct_helper_destroy(ct); 244 spin_lock_bh(&nf_conntrack_lock); 245 /* Inside lock so preempt is disabled on module removal path. 246 * Otherwise we can get spurious warnings. */ 247 NF_CT_STAT_INC(net, delete_list); 248 clean_from_lists(ct); 249 /* add this conntrack to the dying list */ 250 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 251 &net->ct.dying); 252 spin_unlock_bh(&nf_conntrack_lock); 253} 254EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 255 256static void death_by_event(unsigned long ul_conntrack) 257{ 258 struct nf_conn *ct = (void *)ul_conntrack; 259 struct net *net = nf_ct_net(ct); 260 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 261 262 BUG_ON(ecache == NULL); 263 264 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 265 /* bad luck, let's retry again */ 266 ecache->timeout.expires = jiffies + 267 (random32() % net->ct.sysctl_events_retry_timeout); 268 add_timer(&ecache->timeout); 269 return; 270 } 271 /* we've got the event delivered, now it's dying */ 272 set_bit(IPS_DYING_BIT, &ct->status); 273 nf_ct_put(ct); 274} 275 276void nf_ct_dying_timeout(struct nf_conn *ct) 277{ 278 struct net *net = nf_ct_net(ct); 279 struct nf_conntrack_ecache *ecache = nf_ct_ecache_find(ct); 280 281 BUG_ON(ecache == NULL); 282 283 /* 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_dying_timeout); 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_dying_timeout(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); 766 767 768/* Allocate a new conntrack: we return -ENOMEM if classification 769 failed due to stress. Otherwise it really is unclassifiable. */ 770static struct nf_conntrack_tuple_hash * 771init_conntrack(struct net *net, struct nf_conn *tmpl, 772 const struct nf_conntrack_tuple *tuple, 773 struct nf_conntrack_l3proto *l3proto, 774 struct nf_conntrack_l4proto *l4proto, 775 struct sk_buff *skb, 776 unsigned int dataoff, u32 hash) 777{ 778 struct nf_conn *ct; 779 struct nf_conn_help *help; 780 struct nf_conntrack_tuple repl_tuple; 781 struct nf_conntrack_ecache *ecache; 782 struct nf_conntrack_expect *exp; 783 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 784 struct nf_conn_timeout *timeout_ext; 785 unsigned int *timeouts; 786 787 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 788 pr_debug("Can't invert tuple.\n"); 789 return NULL; 790 } 791 792 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 793 hash); 794 if (IS_ERR(ct)) 795 return (struct nf_conntrack_tuple_hash *)ct; 796 797 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; 798 if (timeout_ext) 799 timeouts = NF_CT_TIMEOUT_EXT_DATA(timeout_ext); 800 else 801 timeouts = l4proto->get_timeouts(net); 802 803 if (!l4proto->new(ct, skb, dataoff, timeouts)) { 804 nf_conntrack_free(ct); 805 pr_debug("init conntrack: can't track with proto module\n"); 806 return NULL; 807 } 808 809 if (timeout_ext) 810 nf_ct_timeout_ext_add(ct, timeout_ext->timeout, GFP_ATOMIC); 811 812 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 813 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 814 nf_ct_labels_ext_add(ct); 815 816 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 817 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 818 ecache ? ecache->expmask : 0, 819 GFP_ATOMIC); 820 821 spin_lock_bh(&nf_conntrack_lock); 822 exp = nf_ct_find_expectation(net, zone, tuple); 823 if (exp) { 824 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 825 ct, exp); 826 /* Welcome, Mr. Bond. We've been expecting you... */ 827 __set_bit(IPS_EXPECTED_BIT, &ct->status); 828 ct->master = exp->master; 829 if (exp->helper) { 830 help = nf_ct_helper_ext_add(ct, exp->helper, 831 GFP_ATOMIC); 832 if (help) 833 rcu_assign_pointer(help->helper, exp->helper); 834 } 835 836#ifdef CONFIG_NF_CONNTRACK_MARK 837 ct->mark = exp->master->mark; 838#endif 839#ifdef CONFIG_NF_CONNTRACK_SECMARK 840 ct->secmark = exp->master->secmark; 841#endif 842 nf_conntrack_get(&ct->master->ct_general); 843 NF_CT_STAT_INC(net, expect_new); 844 } else { 845 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 846 NF_CT_STAT_INC(net, new); 847 } 848 849 /* Overload tuple linked list to put us in unconfirmed list. */ 850 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 851 &net->ct.unconfirmed); 852 853 spin_unlock_bh(&nf_conntrack_lock); 854 855 if (exp) { 856 if (exp->expectfn) 857 exp->expectfn(ct, exp); 858 nf_ct_expect_put(exp); 859 } 860 861 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 862} 863 864/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 865static inline struct nf_conn * 866resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 867 struct sk_buff *skb, 868 unsigned int dataoff, 869 u_int16_t l3num, 870 u_int8_t protonum, 871 struct nf_conntrack_l3proto *l3proto, 872 struct nf_conntrack_l4proto *l4proto, 873 int *set_reply, 874 enum ip_conntrack_info *ctinfo) 875{ 876 struct nf_conntrack_tuple tuple; 877 struct nf_conntrack_tuple_hash *h; 878 struct nf_conn *ct; 879 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 880 u32 hash; 881 882 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 883 dataoff, l3num, protonum, &tuple, l3proto, 884 l4proto)) { 885 pr_debug("resolve_normal_ct: Can't get tuple\n"); 886 return NULL; 887 } 888 889 /* look for tuple match */ 890 hash = hash_conntrack_raw(&tuple, zone); 891 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 892 if (!h) { 893 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 894 skb, dataoff, hash); 895 if (!h) 896 return NULL; 897 if (IS_ERR(h)) 898 return (void *)h; 899 } 900 ct = nf_ct_tuplehash_to_ctrack(h); 901 902 /* It exists; we have (non-exclusive) reference. */ 903 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 904 *ctinfo = IP_CT_ESTABLISHED_REPLY; 905 /* Please set reply bit if this packet OK */ 906 *set_reply = 1; 907 } else { 908 /* Once we've had two way comms, always ESTABLISHED. */ 909 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 910 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 911 *ctinfo = IP_CT_ESTABLISHED; 912 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 913 pr_debug("nf_conntrack_in: related packet for %p\n", 914 ct); 915 *ctinfo = IP_CT_RELATED; 916 } else { 917 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 918 *ctinfo = IP_CT_NEW; 919 } 920 *set_reply = 0; 921 } 922 skb->nfct = &ct->ct_general; 923 skb->nfctinfo = *ctinfo; 924 return ct; 925} 926 927unsigned int 928nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 929 struct sk_buff *skb) 930{ 931 struct nf_conn *ct, *tmpl = NULL; 932 enum ip_conntrack_info ctinfo; 933 struct nf_conntrack_l3proto *l3proto; 934 struct nf_conntrack_l4proto *l4proto; 935 unsigned int *timeouts; 936 unsigned int dataoff; 937 u_int8_t protonum; 938 int set_reply = 0; 939 int ret; 940 941 if (skb->nfct) { 942 /* Previously seen (loopback or untracked)? Ignore. */ 943 tmpl = (struct nf_conn *)skb->nfct; 944 if (!nf_ct_is_template(tmpl)) { 945 NF_CT_STAT_INC_ATOMIC(net, ignore); 946 return NF_ACCEPT; 947 } 948 skb->nfct = NULL; 949 } 950 951 /* rcu_read_lock()ed by nf_hook_slow */ 952 l3proto = __nf_ct_l3proto_find(pf); 953 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 954 &dataoff, &protonum); 955 if (ret <= 0) { 956 pr_debug("not prepared to track yet or error occurred\n"); 957 NF_CT_STAT_INC_ATOMIC(net, error); 958 NF_CT_STAT_INC_ATOMIC(net, invalid); 959 ret = -ret; 960 goto out; 961 } 962 963 l4proto = __nf_ct_l4proto_find(pf, protonum); 964 965 /* It may be an special packet, error, unclean... 966 * inverse of the return code tells to the netfilter 967 * core what to do with the packet. */ 968 if (l4proto->error != NULL) { 969 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 970 pf, hooknum); 971 if (ret <= 0) { 972 NF_CT_STAT_INC_ATOMIC(net, error); 973 NF_CT_STAT_INC_ATOMIC(net, invalid); 974 ret = -ret; 975 goto out; 976 } 977 /* ICMP[v6] protocol trackers may assign one conntrack. */ 978 if (skb->nfct) 979 goto out; 980 } 981 982 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 983 l3proto, l4proto, &set_reply, &ctinfo); 984 if (!ct) { 985 /* Not valid part of a connection */ 986 NF_CT_STAT_INC_ATOMIC(net, invalid); 987 ret = NF_ACCEPT; 988 goto out; 989 } 990 991 if (IS_ERR(ct)) { 992 /* Too stressed to deal. */ 993 NF_CT_STAT_INC_ATOMIC(net, drop); 994 ret = NF_DROP; 995 goto out; 996 } 997 998 NF_CT_ASSERT(skb->nfct); 999 1000 /* Decide what timeout policy we want to apply to this flow. */ 1001 timeouts = nf_ct_timeout_lookup(net, ct, l4proto); 1002 1003 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts); 1004 if (ret <= 0) { 1005 /* Invalid: inverse of the return code tells 1006 * the netfilter core what to do */ 1007 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 1008 nf_conntrack_put(skb->nfct); 1009 skb->nfct = NULL; 1010 NF_CT_STAT_INC_ATOMIC(net, invalid); 1011 if (ret == -NF_DROP) 1012 NF_CT_STAT_INC_ATOMIC(net, drop); 1013 ret = -ret; 1014 goto out; 1015 } 1016 1017 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 1018 nf_conntrack_event_cache(IPCT_REPLY, ct); 1019out: 1020 if (tmpl) { 1021 /* Special case: we have to repeat this hook, assign the 1022 * template again to this packet. We assume that this packet 1023 * has no conntrack assigned. This is used by nf_ct_tcp. */ 1024 if (ret == NF_REPEAT) 1025 skb->nfct = (struct nf_conntrack *)tmpl; 1026 else 1027 nf_ct_put(tmpl); 1028 } 1029 1030 return ret; 1031} 1032EXPORT_SYMBOL_GPL(nf_conntrack_in); 1033 1034bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 1035 const struct nf_conntrack_tuple *orig) 1036{ 1037 bool ret; 1038 1039 rcu_read_lock(); 1040 ret = nf_ct_invert_tuple(inverse, orig, 1041 __nf_ct_l3proto_find(orig->src.l3num), 1042 __nf_ct_l4proto_find(orig->src.l3num, 1043 orig->dst.protonum)); 1044 rcu_read_unlock(); 1045 return ret; 1046} 1047EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 1048 1049/* Alter reply tuple (maybe alter helper). This is for NAT, and is 1050 implicitly racy: see __nf_conntrack_confirm */ 1051void nf_conntrack_alter_reply(struct nf_conn *ct, 1052 const struct nf_conntrack_tuple *newreply) 1053{ 1054 struct nf_conn_help *help = nfct_help(ct); 1055 1056 /* Should be unconfirmed, so not in hash table yet */ 1057 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 1058 1059 pr_debug("Altering reply tuple of %p to ", ct); 1060 nf_ct_dump_tuple(newreply); 1061 1062 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 1063 if (ct->master || (help && !hlist_empty(&help->expectations))) 1064 return; 1065 1066 rcu_read_lock(); 1067 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 1068 rcu_read_unlock(); 1069} 1070EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 1071 1072/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 1073void __nf_ct_refresh_acct(struct nf_conn *ct, 1074 enum ip_conntrack_info ctinfo, 1075 const struct sk_buff *skb, 1076 unsigned long extra_jiffies, 1077 int do_acct) 1078{ 1079 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 1080 NF_CT_ASSERT(skb); 1081 1082 /* Only update if this is not a fixed timeout */ 1083 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 1084 goto acct; 1085 1086 /* If not in hash table, timer will not be active yet */ 1087 if (!nf_ct_is_confirmed(ct)) { 1088 ct->timeout.expires = extra_jiffies; 1089 } else { 1090 unsigned long newtime = jiffies + extra_jiffies; 1091 1092 /* Only update the timeout if the new timeout is at least 1093 HZ jiffies from the old timeout. Need del_timer for race 1094 avoidance (may already be dying). */ 1095 if (newtime - ct->timeout.expires >= HZ) 1096 mod_timer_pending(&ct->timeout, newtime); 1097 } 1098 1099acct: 1100 if (do_acct) { 1101 struct nf_conn_counter *acct; 1102 1103 acct = nf_conn_acct_find(ct); 1104 if (acct) { 1105 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1106 atomic64_add(skb->len, &acct[CTINFO2DIR(ctinfo)].bytes); 1107 } 1108 } 1109} 1110EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1111 1112bool __nf_ct_kill_acct(struct nf_conn *ct, 1113 enum ip_conntrack_info ctinfo, 1114 const struct sk_buff *skb, 1115 int do_acct) 1116{ 1117 if (do_acct) { 1118 struct nf_conn_counter *acct; 1119 1120 acct = nf_conn_acct_find(ct); 1121 if (acct) { 1122 atomic64_inc(&acct[CTINFO2DIR(ctinfo)].packets); 1123 atomic64_add(skb->len - skb_network_offset(skb), 1124 &acct[CTINFO2DIR(ctinfo)].bytes); 1125 } 1126 } 1127 1128 if (del_timer(&ct->timeout)) { 1129 ct->timeout.function((unsigned long)ct); 1130 return true; 1131 } 1132 return false; 1133} 1134EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1135 1136#ifdef CONFIG_NF_CONNTRACK_ZONES 1137static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1138 .len = sizeof(struct nf_conntrack_zone), 1139 .align = __alignof__(struct nf_conntrack_zone), 1140 .id = NF_CT_EXT_ZONE, 1141}; 1142#endif 1143 1144#if IS_ENABLED(CONFIG_NF_CT_NETLINK) 1145 1146#include <linux/netfilter/nfnetlink.h> 1147#include <linux/netfilter/nfnetlink_conntrack.h> 1148#include <linux/mutex.h> 1149 1150/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1151 * in ip_conntrack_core, since we don't want the protocols to autoload 1152 * or depend on ctnetlink */ 1153int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1154 const struct nf_conntrack_tuple *tuple) 1155{ 1156 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) || 1157 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port)) 1158 goto nla_put_failure; 1159 return 0; 1160 1161nla_put_failure: 1162 return -1; 1163} 1164EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1165 1166const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1167 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1168 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1169}; 1170EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1171 1172int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1173 struct nf_conntrack_tuple *t) 1174{ 1175 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1176 return -EINVAL; 1177 1178 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1179 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1180 1181 return 0; 1182} 1183EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1184 1185int nf_ct_port_nlattr_tuple_size(void) 1186{ 1187 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1188} 1189EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1190#endif 1191 1192/* Used by ipt_REJECT and ip6t_REJECT. */ 1193static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1194{ 1195 struct nf_conn *ct; 1196 enum ip_conntrack_info ctinfo; 1197 1198 /* This ICMP is in reverse direction to the packet which caused it */ 1199 ct = nf_ct_get(skb, &ctinfo); 1200 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1201 ctinfo = IP_CT_RELATED_REPLY; 1202 else 1203 ctinfo = IP_CT_RELATED; 1204 1205 /* Attach to new skbuff, and increment count */ 1206 nskb->nfct = &ct->ct_general; 1207 nskb->nfctinfo = ctinfo; 1208 nf_conntrack_get(nskb->nfct); 1209} 1210 1211/* Bring out ya dead! */ 1212static struct nf_conn * 1213get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1214 void *data, unsigned int *bucket) 1215{ 1216 struct nf_conntrack_tuple_hash *h; 1217 struct nf_conn *ct; 1218 struct hlist_nulls_node *n; 1219 1220 spin_lock_bh(&nf_conntrack_lock); 1221 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1222 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1223 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL) 1224 continue; 1225 ct = nf_ct_tuplehash_to_ctrack(h); 1226 if (iter(ct, data)) 1227 goto found; 1228 } 1229 } 1230 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1231 ct = nf_ct_tuplehash_to_ctrack(h); 1232 if (iter(ct, data)) 1233 set_bit(IPS_DYING_BIT, &ct->status); 1234 } 1235 spin_unlock_bh(&nf_conntrack_lock); 1236 return NULL; 1237found: 1238 atomic_inc(&ct->ct_general.use); 1239 spin_unlock_bh(&nf_conntrack_lock); 1240 return ct; 1241} 1242 1243void nf_ct_iterate_cleanup(struct net *net, 1244 int (*iter)(struct nf_conn *i, void *data), 1245 void *data) 1246{ 1247 struct nf_conn *ct; 1248 unsigned int bucket = 0; 1249 1250 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1251 /* Time to push up daises... */ 1252 if (del_timer(&ct->timeout)) 1253 death_by_timeout((unsigned long)ct); 1254 /* ... else the timer will get him soon. */ 1255 1256 nf_ct_put(ct); 1257 } 1258} 1259EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1260 1261struct __nf_ct_flush_report { 1262 u32 pid; 1263 int report; 1264}; 1265 1266static int kill_report(struct nf_conn *i, void *data) 1267{ 1268 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1269 struct nf_conn_tstamp *tstamp; 1270 1271 tstamp = nf_conn_tstamp_find(i); 1272 if (tstamp && tstamp->stop == 0) 1273 tstamp->stop = ktime_to_ns(ktime_get_real()); 1274 1275 /* If we fail to deliver the event, death_by_timeout() will retry */ 1276 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1277 fr->pid, fr->report) < 0) 1278 return 1; 1279 1280 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1281 set_bit(IPS_DYING_BIT, &i->status); 1282 return 1; 1283} 1284 1285static int kill_all(struct nf_conn *i, void *data) 1286{ 1287 return 1; 1288} 1289 1290void nf_ct_free_hashtable(void *hash, unsigned int size) 1291{ 1292 if (is_vmalloc_addr(hash)) 1293 vfree(hash); 1294 else 1295 free_pages((unsigned long)hash, 1296 get_order(sizeof(struct hlist_head) * size)); 1297} 1298EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1299 1300void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1301{ 1302 struct __nf_ct_flush_report fr = { 1303 .pid = pid, 1304 .report = report, 1305 }; 1306 nf_ct_iterate_cleanup(net, kill_report, &fr); 1307} 1308EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1309 1310static void nf_ct_release_dying_list(struct net *net) 1311{ 1312 struct nf_conntrack_tuple_hash *h; 1313 struct nf_conn *ct; 1314 struct hlist_nulls_node *n; 1315 1316 spin_lock_bh(&nf_conntrack_lock); 1317 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1318 ct = nf_ct_tuplehash_to_ctrack(h); 1319 /* never fails to remove them, no listeners at this point */ 1320 nf_ct_kill(ct); 1321 } 1322 spin_unlock_bh(&nf_conntrack_lock); 1323} 1324 1325static int untrack_refs(void) 1326{ 1327 int cnt = 0, cpu; 1328 1329 for_each_possible_cpu(cpu) { 1330 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1331 1332 cnt += atomic_read(&ct->ct_general.use) - 1; 1333 } 1334 return cnt; 1335} 1336 1337void nf_conntrack_cleanup_start(void) 1338{ 1339 RCU_INIT_POINTER(ip_ct_attach, NULL); 1340} 1341 1342void nf_conntrack_cleanup_end(void) 1343{ 1344 RCU_INIT_POINTER(nf_ct_destroy, NULL); 1345 while (untrack_refs() > 0) 1346 schedule(); 1347 1348#ifdef CONFIG_NF_CONNTRACK_ZONES 1349 nf_ct_extend_unregister(&nf_ct_zone_extend); 1350#endif 1351 nf_conntrack_timeout_fini(); 1352 nf_conntrack_ecache_fini(); 1353 nf_conntrack_tstamp_fini(); 1354 nf_conntrack_acct_fini(); 1355 nf_conntrack_expect_fini(); 1356} 1357 1358/* 1359 * Mishearing the voices in his head, our hero wonders how he's 1360 * supposed to kill the mall. 1361 */ 1362void nf_conntrack_cleanup_net(struct net *net) 1363{ 1364 /* 1365 * This makes sure all current packets have passed through 1366 * netfilter framework. Roll on, two-stage module 1367 * delete... 1368 */ 1369 synchronize_net(); 1370 i_see_dead_people: 1371 nf_ct_iterate_cleanup(net, kill_all, NULL); 1372 nf_ct_release_dying_list(net); 1373 if (atomic_read(&net->ct.count) != 0) { 1374 schedule(); 1375 goto i_see_dead_people; 1376 } 1377 1378 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1379 nf_conntrack_proto_fini(net); 1380 nf_conntrack_labels_fini(net); 1381 nf_conntrack_helper_fini(net); 1382 nf_conntrack_ecache_pernet_fini(net); 1383 nf_conntrack_tstamp_pernet_fini(net); 1384 nf_conntrack_acct_pernet_fini(net); 1385 nf_conntrack_expect_pernet_fini(net); 1386 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1387 kfree(net->ct.slabname); 1388 free_percpu(net->ct.stat); 1389} 1390 1391void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 1392{ 1393 struct hlist_nulls_head *hash; 1394 unsigned int nr_slots, i; 1395 size_t sz; 1396 1397 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1398 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1399 sz = nr_slots * sizeof(struct hlist_nulls_head); 1400 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1401 get_order(sz)); 1402 if (!hash) { 1403 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1404 hash = vzalloc(sz); 1405 } 1406 1407 if (hash && nulls) 1408 for (i = 0; i < nr_slots; i++) 1409 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1410 1411 return hash; 1412} 1413EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1414 1415int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1416{ 1417 int i, bucket, rc; 1418 unsigned int hashsize, old_size; 1419 struct hlist_nulls_head *hash, *old_hash; 1420 struct nf_conntrack_tuple_hash *h; 1421 struct nf_conn *ct; 1422 1423 if (current->nsproxy->net_ns != &init_net) 1424 return -EOPNOTSUPP; 1425 1426 /* On boot, we can set this without any fancy locking. */ 1427 if (!nf_conntrack_htable_size) 1428 return param_set_uint(val, kp); 1429 1430 rc = kstrtouint(val, 0, &hashsize); 1431 if (rc) 1432 return rc; 1433 if (!hashsize) 1434 return -EINVAL; 1435 1436 hash = nf_ct_alloc_hashtable(&hashsize, 1); 1437 if (!hash) 1438 return -ENOMEM; 1439 1440 /* Lookups in the old hash might happen in parallel, which means we 1441 * might get false negatives during connection lookup. New connections 1442 * created because of a false negative won't make it into the hash 1443 * though since that required taking the lock. 1444 */ 1445 spin_lock_bh(&nf_conntrack_lock); 1446 for (i = 0; i < init_net.ct.htable_size; i++) { 1447 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1448 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1449 struct nf_conntrack_tuple_hash, hnnode); 1450 ct = nf_ct_tuplehash_to_ctrack(h); 1451 hlist_nulls_del_rcu(&h->hnnode); 1452 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1453 hashsize); 1454 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1455 } 1456 } 1457 old_size = init_net.ct.htable_size; 1458 old_hash = init_net.ct.hash; 1459 1460 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1461 init_net.ct.hash = hash; 1462 spin_unlock_bh(&nf_conntrack_lock); 1463 1464 nf_ct_free_hashtable(old_hash, old_size); 1465 return 0; 1466} 1467EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1468 1469module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1470 &nf_conntrack_htable_size, 0600); 1471 1472void nf_ct_untracked_status_or(unsigned long bits) 1473{ 1474 int cpu; 1475 1476 for_each_possible_cpu(cpu) 1477 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1478} 1479EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1480 1481int nf_conntrack_init_start(void) 1482{ 1483 int max_factor = 8; 1484 int ret, cpu; 1485 1486 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1487 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1488 if (!nf_conntrack_htable_size) { 1489 nf_conntrack_htable_size 1490 = (((totalram_pages << PAGE_SHIFT) / 16384) 1491 / sizeof(struct hlist_head)); 1492 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1493 nf_conntrack_htable_size = 16384; 1494 if (nf_conntrack_htable_size < 32) 1495 nf_conntrack_htable_size = 32; 1496 1497 /* Use a max. factor of four by default to get the same max as 1498 * with the old struct list_heads. When a table size is given 1499 * we use the old value of 8 to avoid reducing the max. 1500 * entries. */ 1501 max_factor = 4; 1502 } 1503 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1504 1505 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1506 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1507 nf_conntrack_max); 1508 1509 ret = nf_conntrack_expect_init(); 1510 if (ret < 0) 1511 goto err_expect; 1512 1513 ret = nf_conntrack_acct_init(); 1514 if (ret < 0) 1515 goto err_acct; 1516 1517 ret = nf_conntrack_tstamp_init(); 1518 if (ret < 0) 1519 goto err_tstamp; 1520 1521 ret = nf_conntrack_ecache_init(); 1522 if (ret < 0) 1523 goto err_ecache; 1524 1525 ret = nf_conntrack_timeout_init(); 1526 if (ret < 0) 1527 goto err_timeout; 1528 1529#ifdef CONFIG_NF_CONNTRACK_ZONES 1530 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1531 if (ret < 0) 1532 goto err_extend; 1533#endif 1534 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1535 for_each_possible_cpu(cpu) { 1536 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1537 write_pnet(&ct->ct_net, &init_net); 1538 atomic_set(&ct->ct_general.use, 1); 1539 } 1540 /* - and look it like as a confirmed connection */ 1541 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1542 return 0; 1543 1544#ifdef CONFIG_NF_CONNTRACK_ZONES 1545err_extend: 1546 nf_conntrack_timeout_fini(); 1547#endif 1548err_timeout: 1549 nf_conntrack_ecache_fini(); 1550err_ecache: 1551 nf_conntrack_tstamp_fini(); 1552err_tstamp: 1553 nf_conntrack_acct_fini(); 1554err_acct: 1555 nf_conntrack_expect_fini(); 1556err_expect: 1557 return ret; 1558} 1559 1560void nf_conntrack_init_end(void) 1561{ 1562 /* For use by REJECT target */ 1563 RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach); 1564 RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack); 1565 1566 /* Howto get NAT offsets */ 1567 RCU_INIT_POINTER(nf_ct_nat_offset, NULL); 1568} 1569 1570/* 1571 * We need to use special "null" values, not used in hash table 1572 */ 1573#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1574#define DYING_NULLS_VAL ((1<<30)+1) 1575#define TEMPLATE_NULLS_VAL ((1<<30)+2) 1576 1577int nf_conntrack_init_net(struct net *net) 1578{ 1579 int ret; 1580 1581 atomic_set(&net->ct.count, 0); 1582 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1583 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1584 INIT_HLIST_NULLS_HEAD(&net->ct.tmpl, TEMPLATE_NULLS_VAL); 1585 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1586 if (!net->ct.stat) { 1587 ret = -ENOMEM; 1588 goto err_stat; 1589 } 1590 1591 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1592 if (!net->ct.slabname) { 1593 ret = -ENOMEM; 1594 goto err_slabname; 1595 } 1596 1597 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1598 sizeof(struct nf_conn), 0, 1599 SLAB_DESTROY_BY_RCU, NULL); 1600 if (!net->ct.nf_conntrack_cachep) { 1601 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1602 ret = -ENOMEM; 1603 goto err_cache; 1604 } 1605 1606 net->ct.htable_size = nf_conntrack_htable_size; 1607 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1); 1608 if (!net->ct.hash) { 1609 ret = -ENOMEM; 1610 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1611 goto err_hash; 1612 } 1613 ret = nf_conntrack_expect_pernet_init(net); 1614 if (ret < 0) 1615 goto err_expect; 1616 ret = nf_conntrack_acct_pernet_init(net); 1617 if (ret < 0) 1618 goto err_acct; 1619 ret = nf_conntrack_tstamp_pernet_init(net); 1620 if (ret < 0) 1621 goto err_tstamp; 1622 ret = nf_conntrack_ecache_pernet_init(net); 1623 if (ret < 0) 1624 goto err_ecache; 1625 ret = nf_conntrack_helper_init(net); 1626 if (ret < 0) 1627 goto err_helper; 1628 1629 ret = nf_conntrack_labels_init(net); 1630 if (ret < 0) 1631 goto err_labels; 1632 1633 ret = nf_conntrack_proto_init(net); 1634 if (ret < 0) 1635 goto err_proto; 1636 return 0; 1637 1638err_proto: 1639 nf_conntrack_labels_fini(net); 1640err_labels: 1641 nf_conntrack_helper_fini(net); 1642err_helper: 1643 nf_conntrack_ecache_pernet_fini(net); 1644err_ecache: 1645 nf_conntrack_tstamp_pernet_fini(net); 1646err_tstamp: 1647 nf_conntrack_acct_pernet_fini(net); 1648err_acct: 1649 nf_conntrack_expect_pernet_fini(net); 1650err_expect: 1651 nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size); 1652err_hash: 1653 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1654err_cache: 1655 kfree(net->ct.slabname); 1656err_slabname: 1657 free_percpu(net->ct.stat); 1658err_stat: 1659 return ret; 1660} 1661 1662s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1663 enum ip_conntrack_dir dir, 1664 u32 seq); 1665EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1666