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_nat.h> 47 #include <net/netfilter/nf_nat_core.h> 48 49 #define NF_CONNTRACK_VERSION "0.5.0" 50 51 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 52 enum nf_nat_manip_type manip, 53 const struct nlattr *attr) __read_mostly; 54 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 55 56 DEFINE_SPINLOCK(nf_conntrack_lock); 57 EXPORT_SYMBOL_GPL(nf_conntrack_lock); 58 59 unsigned int nf_conntrack_htable_size __read_mostly; 60 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 61 62 unsigned int nf_conntrack_max __read_mostly; 63 EXPORT_SYMBOL_GPL(nf_conntrack_max); 64 65 DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked); 66 EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked); 67 68 static unsigned int nf_conntrack_hash_rnd __read_mostly; 69 70 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) 71 { 72 unsigned int n; 73 74 /* The direction must be ignored, so we hash everything up to the 75 * destination ports (which is a multiple of 4) and treat the last 76 * three bytes manually. 77 */ 78 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 79 return jhash2((u32 *)tuple, n, zone ^ nf_conntrack_hash_rnd ^ 80 (((__force __u16)tuple->dst.u.all << 16) | 81 tuple->dst.protonum)); 82 } 83 84 static u32 __hash_bucket(u32 hash, unsigned int size) 85 { 86 return ((u64)hash * size) >> 32; 87 } 88 89 static u32 hash_bucket(u32 hash, const struct net *net) 90 { 91 return __hash_bucket(hash, net->ct.htable_size); 92 } 93 94 static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 95 u16 zone, unsigned int size) 96 { 97 return __hash_bucket(hash_conntrack_raw(tuple, zone), size); 98 } 99 100 static inline u_int32_t hash_conntrack(const struct net *net, u16 zone, 101 const struct nf_conntrack_tuple *tuple) 102 { 103 return __hash_conntrack(tuple, zone, net->ct.htable_size); 104 } 105 106 bool 107 nf_ct_get_tuple(const struct sk_buff *skb, 108 unsigned int nhoff, 109 unsigned int dataoff, 110 u_int16_t l3num, 111 u_int8_t protonum, 112 struct nf_conntrack_tuple *tuple, 113 const struct nf_conntrack_l3proto *l3proto, 114 const struct nf_conntrack_l4proto *l4proto) 115 { 116 memset(tuple, 0, sizeof(*tuple)); 117 118 tuple->src.l3num = l3num; 119 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 120 return false; 121 122 tuple->dst.protonum = protonum; 123 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 124 125 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 126 } 127 EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 128 129 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 130 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 131 { 132 struct nf_conntrack_l3proto *l3proto; 133 struct nf_conntrack_l4proto *l4proto; 134 unsigned int protoff; 135 u_int8_t protonum; 136 int ret; 137 138 rcu_read_lock(); 139 140 l3proto = __nf_ct_l3proto_find(l3num); 141 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 142 if (ret != NF_ACCEPT) { 143 rcu_read_unlock(); 144 return false; 145 } 146 147 l4proto = __nf_ct_l4proto_find(l3num, protonum); 148 149 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 150 l3proto, l4proto); 151 152 rcu_read_unlock(); 153 return ret; 154 } 155 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 156 157 bool 158 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 159 const struct nf_conntrack_tuple *orig, 160 const struct nf_conntrack_l3proto *l3proto, 161 const struct nf_conntrack_l4proto *l4proto) 162 { 163 memset(inverse, 0, sizeof(*inverse)); 164 165 inverse->src.l3num = orig->src.l3num; 166 if (l3proto->invert_tuple(inverse, orig) == 0) 167 return false; 168 169 inverse->dst.dir = !orig->dst.dir; 170 171 inverse->dst.protonum = orig->dst.protonum; 172 return l4proto->invert_tuple(inverse, orig); 173 } 174 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 175 176 static void 177 clean_from_lists(struct nf_conn *ct) 178 { 179 pr_debug("clean_from_lists(%p)\n", ct); 180 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 181 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 182 183 /* Destroy all pending expectations */ 184 nf_ct_remove_expectations(ct); 185 } 186 187 static void 188 destroy_conntrack(struct nf_conntrack *nfct) 189 { 190 struct nf_conn *ct = (struct nf_conn *)nfct; 191 struct net *net = nf_ct_net(ct); 192 struct nf_conntrack_l4proto *l4proto; 193 194 pr_debug("destroy_conntrack(%p)\n", ct); 195 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 196 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 197 198 /* To make sure we don't get any weird locking issues here: 199 * destroy_conntrack() MUST NOT be called with a write lock 200 * to nf_conntrack_lock!!! -HW */ 201 rcu_read_lock(); 202 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 203 if (l4proto && l4proto->destroy) 204 l4proto->destroy(ct); 205 206 rcu_read_unlock(); 207 208 spin_lock_bh(&nf_conntrack_lock); 209 /* Expectations will have been removed in clean_from_lists, 210 * except TFTP can create an expectation on the first packet, 211 * before connection is in the list, so we need to clean here, 212 * too. */ 213 nf_ct_remove_expectations(ct); 214 215 /* We overload first tuple to link into unconfirmed list. */ 216 if (!nf_ct_is_confirmed(ct)) { 217 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 218 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 219 } 220 221 NF_CT_STAT_INC(net, delete); 222 spin_unlock_bh(&nf_conntrack_lock); 223 224 if (ct->master) 225 nf_ct_put(ct->master); 226 227 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 228 nf_conntrack_free(ct); 229 } 230 231 void nf_ct_delete_from_lists(struct nf_conn *ct) 232 { 233 struct net *net = nf_ct_net(ct); 234 235 nf_ct_helper_destroy(ct); 236 spin_lock_bh(&nf_conntrack_lock); 237 /* Inside lock so preempt is disabled on module removal path. 238 * Otherwise we can get spurious warnings. */ 239 NF_CT_STAT_INC(net, delete_list); 240 clean_from_lists(ct); 241 spin_unlock_bh(&nf_conntrack_lock); 242 } 243 EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 244 245 static void death_by_event(unsigned long ul_conntrack) 246 { 247 struct nf_conn *ct = (void *)ul_conntrack; 248 struct net *net = nf_ct_net(ct); 249 250 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 251 /* bad luck, let's retry again */ 252 ct->timeout.expires = jiffies + 253 (random32() % net->ct.sysctl_events_retry_timeout); 254 add_timer(&ct->timeout); 255 return; 256 } 257 /* we've got the event delivered, now it's dying */ 258 set_bit(IPS_DYING_BIT, &ct->status); 259 spin_lock(&nf_conntrack_lock); 260 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 261 spin_unlock(&nf_conntrack_lock); 262 nf_ct_put(ct); 263 } 264 265 void nf_ct_insert_dying_list(struct nf_conn *ct) 266 { 267 struct net *net = nf_ct_net(ct); 268 269 /* add this conntrack to the dying list */ 270 spin_lock_bh(&nf_conntrack_lock); 271 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 272 &net->ct.dying); 273 spin_unlock_bh(&nf_conntrack_lock); 274 /* set a new timer to retry event delivery */ 275 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); 276 ct->timeout.expires = jiffies + 277 (random32() % net->ct.sysctl_events_retry_timeout); 278 add_timer(&ct->timeout); 279 } 280 EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); 281 282 static void death_by_timeout(unsigned long ul_conntrack) 283 { 284 struct nf_conn *ct = (void *)ul_conntrack; 285 286 if (!test_bit(IPS_DYING_BIT, &ct->status) && 287 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 288 /* destroy event was not delivered */ 289 nf_ct_delete_from_lists(ct); 290 nf_ct_insert_dying_list(ct); 291 return; 292 } 293 set_bit(IPS_DYING_BIT, &ct->status); 294 nf_ct_delete_from_lists(ct); 295 nf_ct_put(ct); 296 } 297 298 /* 299 * Warning : 300 * - Caller must take a reference on returned object 301 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 302 * OR 303 * - Caller must lock nf_conntrack_lock before calling this function 304 */ 305 static struct nf_conntrack_tuple_hash * 306 ____nf_conntrack_find(struct net *net, u16 zone, 307 const struct nf_conntrack_tuple *tuple, u32 hash) 308 { 309 struct nf_conntrack_tuple_hash *h; 310 struct hlist_nulls_node *n; 311 unsigned int bucket = hash_bucket(hash, net); 312 313 /* Disable BHs the entire time since we normally need to disable them 314 * at least once for the stats anyway. 315 */ 316 local_bh_disable(); 317 begin: 318 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[bucket], hnnode) { 319 if (nf_ct_tuple_equal(tuple, &h->tuple) && 320 nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)) == zone) { 321 NF_CT_STAT_INC(net, found); 322 local_bh_enable(); 323 return h; 324 } 325 NF_CT_STAT_INC(net, searched); 326 } 327 /* 328 * if the nulls value we got at the end of this lookup is 329 * not the expected one, we must restart lookup. 330 * We probably met an item that was moved to another chain. 331 */ 332 if (get_nulls_value(n) != bucket) { 333 NF_CT_STAT_INC(net, search_restart); 334 goto begin; 335 } 336 local_bh_enable(); 337 338 return NULL; 339 } 340 341 struct nf_conntrack_tuple_hash * 342 __nf_conntrack_find(struct net *net, u16 zone, 343 const struct nf_conntrack_tuple *tuple) 344 { 345 return ____nf_conntrack_find(net, zone, tuple, 346 hash_conntrack_raw(tuple, zone)); 347 } 348 EXPORT_SYMBOL_GPL(__nf_conntrack_find); 349 350 /* Find a connection corresponding to a tuple. */ 351 static struct nf_conntrack_tuple_hash * 352 __nf_conntrack_find_get(struct net *net, u16 zone, 353 const struct nf_conntrack_tuple *tuple, u32 hash) 354 { 355 struct nf_conntrack_tuple_hash *h; 356 struct nf_conn *ct; 357 358 rcu_read_lock(); 359 begin: 360 h = ____nf_conntrack_find(net, zone, tuple, hash); 361 if (h) { 362 ct = nf_ct_tuplehash_to_ctrack(h); 363 if (unlikely(nf_ct_is_dying(ct) || 364 !atomic_inc_not_zero(&ct->ct_general.use))) 365 h = NULL; 366 else { 367 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple) || 368 nf_ct_zone(ct) != zone)) { 369 nf_ct_put(ct); 370 goto begin; 371 } 372 } 373 } 374 rcu_read_unlock(); 375 376 return h; 377 } 378 379 struct nf_conntrack_tuple_hash * 380 nf_conntrack_find_get(struct net *net, u16 zone, 381 const struct nf_conntrack_tuple *tuple) 382 { 383 return __nf_conntrack_find_get(net, zone, tuple, 384 hash_conntrack_raw(tuple, zone)); 385 } 386 EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 387 388 static void __nf_conntrack_hash_insert(struct nf_conn *ct, 389 unsigned int hash, 390 unsigned int repl_hash) 391 { 392 struct net *net = nf_ct_net(ct); 393 394 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 395 &net->ct.hash[hash]); 396 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 397 &net->ct.hash[repl_hash]); 398 } 399 400 void nf_conntrack_hash_insert(struct nf_conn *ct) 401 { 402 struct net *net = nf_ct_net(ct); 403 unsigned int hash, repl_hash; 404 u16 zone; 405 406 zone = nf_ct_zone(ct); 407 hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 408 repl_hash = hash_conntrack(net, zone, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 409 410 __nf_conntrack_hash_insert(ct, hash, repl_hash); 411 } 412 EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert); 413 414 /* Confirm a connection given skb; places it in hash table */ 415 int 416 __nf_conntrack_confirm(struct sk_buff *skb) 417 { 418 unsigned int hash, repl_hash; 419 struct nf_conntrack_tuple_hash *h; 420 struct nf_conn *ct; 421 struct nf_conn_help *help; 422 struct hlist_nulls_node *n; 423 enum ip_conntrack_info ctinfo; 424 struct net *net; 425 u16 zone; 426 427 ct = nf_ct_get(skb, &ctinfo); 428 net = nf_ct_net(ct); 429 430 /* ipt_REJECT uses nf_conntrack_attach to attach related 431 ICMP/TCP RST packets in other direction. Actual packet 432 which created connection will be IP_CT_NEW or for an 433 expected connection, IP_CT_RELATED. */ 434 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 435 return NF_ACCEPT; 436 437 zone = nf_ct_zone(ct); 438 /* reuse the hash saved before */ 439 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 440 hash = hash_bucket(hash, net); 441 repl_hash = hash_conntrack(net, zone, 442 &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 443 444 /* We're not in hash table, and we refuse to set up related 445 connections for unconfirmed conns. But packet copies and 446 REJECT will give spurious warnings here. */ 447 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 448 449 /* No external references means noone else could have 450 confirmed us. */ 451 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 452 pr_debug("Confirming conntrack %p\n", ct); 453 454 spin_lock_bh(&nf_conntrack_lock); 455 456 /* We have to check the DYING flag inside the lock to prevent 457 a race against nf_ct_get_next_corpse() possibly called from 458 user context, else we insert an already 'dead' hash, blocking 459 further use of that particular connection -JM */ 460 461 if (unlikely(nf_ct_is_dying(ct))) { 462 spin_unlock_bh(&nf_conntrack_lock); 463 return NF_ACCEPT; 464 } 465 466 /* See if there's one in the list already, including reverse: 467 NAT could have grabbed it without realizing, since we're 468 not in the hash. If there is, we lost race. */ 469 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 470 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 471 &h->tuple) && 472 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 473 goto out; 474 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 475 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 476 &h->tuple) && 477 zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h))) 478 goto out; 479 480 /* Remove from unconfirmed list */ 481 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 482 483 /* Timer relative to confirmation time, not original 484 setting time, otherwise we'd get timer wrap in 485 weird delay cases. */ 486 ct->timeout.expires += jiffies; 487 add_timer(&ct->timeout); 488 atomic_inc(&ct->ct_general.use); 489 set_bit(IPS_CONFIRMED_BIT, &ct->status); 490 491 /* Since the lookup is lockless, hash insertion must be done after 492 * starting the timer and setting the CONFIRMED bit. The RCU barriers 493 * guarantee that no other CPU can find the conntrack before the above 494 * stores are visible. 495 */ 496 __nf_conntrack_hash_insert(ct, hash, repl_hash); 497 NF_CT_STAT_INC(net, insert); 498 spin_unlock_bh(&nf_conntrack_lock); 499 500 help = nfct_help(ct); 501 if (help && help->helper) 502 nf_conntrack_event_cache(IPCT_HELPER, ct); 503 504 nf_conntrack_event_cache(master_ct(ct) ? 505 IPCT_RELATED : IPCT_NEW, ct); 506 return NF_ACCEPT; 507 508 out: 509 NF_CT_STAT_INC(net, insert_failed); 510 spin_unlock_bh(&nf_conntrack_lock); 511 return NF_DROP; 512 } 513 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 514 515 /* Returns true if a connection correspondings to the tuple (required 516 for NAT). */ 517 int 518 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 519 const struct nf_conn *ignored_conntrack) 520 { 521 struct net *net = nf_ct_net(ignored_conntrack); 522 struct nf_conntrack_tuple_hash *h; 523 struct hlist_nulls_node *n; 524 struct nf_conn *ct; 525 u16 zone = nf_ct_zone(ignored_conntrack); 526 unsigned int hash = hash_conntrack(net, zone, tuple); 527 528 /* Disable BHs the entire time since we need to disable them at 529 * least once for the stats anyway. 530 */ 531 rcu_read_lock_bh(); 532 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 533 ct = nf_ct_tuplehash_to_ctrack(h); 534 if (ct != ignored_conntrack && 535 nf_ct_tuple_equal(tuple, &h->tuple) && 536 nf_ct_zone(ct) == zone) { 537 NF_CT_STAT_INC(net, found); 538 rcu_read_unlock_bh(); 539 return 1; 540 } 541 NF_CT_STAT_INC(net, searched); 542 } 543 rcu_read_unlock_bh(); 544 545 return 0; 546 } 547 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 548 549 #define NF_CT_EVICTION_RANGE 8 550 551 /* There's a small race here where we may free a just-assured 552 connection. Too bad: we're in trouble anyway. */ 553 static noinline int early_drop(struct net *net, unsigned int hash) 554 { 555 /* Use oldest entry, which is roughly LRU */ 556 struct nf_conntrack_tuple_hash *h; 557 struct nf_conn *ct = NULL, *tmp; 558 struct hlist_nulls_node *n; 559 unsigned int i, cnt = 0; 560 int dropped = 0; 561 562 rcu_read_lock(); 563 for (i = 0; i < net->ct.htable_size; i++) { 564 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 565 hnnode) { 566 tmp = nf_ct_tuplehash_to_ctrack(h); 567 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 568 ct = tmp; 569 cnt++; 570 } 571 572 if (ct != NULL) { 573 if (likely(!nf_ct_is_dying(ct) && 574 atomic_inc_not_zero(&ct->ct_general.use))) 575 break; 576 else 577 ct = NULL; 578 } 579 580 if (cnt >= NF_CT_EVICTION_RANGE) 581 break; 582 583 hash = (hash + 1) % net->ct.htable_size; 584 } 585 rcu_read_unlock(); 586 587 if (!ct) 588 return dropped; 589 590 if (del_timer(&ct->timeout)) { 591 death_by_timeout((unsigned long)ct); 592 dropped = 1; 593 NF_CT_STAT_INC_ATOMIC(net, early_drop); 594 } 595 nf_ct_put(ct); 596 return dropped; 597 } 598 599 static struct nf_conn * 600 __nf_conntrack_alloc(struct net *net, u16 zone, 601 const struct nf_conntrack_tuple *orig, 602 const struct nf_conntrack_tuple *repl, 603 gfp_t gfp, u32 hash) 604 { 605 struct nf_conn *ct; 606 607 if (unlikely(!nf_conntrack_hash_rnd)) { 608 unsigned int rand; 609 610 /* 611 * Why not initialize nf_conntrack_rnd in a "init()" function ? 612 * Because there isn't enough entropy when system initializing, 613 * and we initialize it as late as possible. 614 */ 615 do { 616 get_random_bytes(&rand, sizeof(rand)); 617 } while (!rand); 618 cmpxchg(&nf_conntrack_hash_rnd, 0, rand); 619 620 /* recompute the hash as nf_conntrack_hash_rnd is initialized */ 621 hash = hash_conntrack_raw(orig, zone); 622 } 623 624 /* We don't want any race condition at early drop stage */ 625 atomic_inc(&net->ct.count); 626 627 if (nf_conntrack_max && 628 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 629 if (!early_drop(net, hash_bucket(hash, net))) { 630 atomic_dec(&net->ct.count); 631 if (net_ratelimit()) 632 printk(KERN_WARNING 633 "nf_conntrack: table full, dropping" 634 " packet.\n"); 635 return ERR_PTR(-ENOMEM); 636 } 637 } 638 639 /* 640 * Do not use kmem_cache_zalloc(), as this cache uses 641 * SLAB_DESTROY_BY_RCU. 642 */ 643 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 644 if (ct == NULL) { 645 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); 646 atomic_dec(&net->ct.count); 647 return ERR_PTR(-ENOMEM); 648 } 649 /* 650 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 651 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 652 */ 653 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 654 sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 655 spin_lock_init(&ct->lock); 656 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 657 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 658 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 659 /* save hash for reusing when confirming */ 660 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 661 /* Don't set timer yet: wait for confirmation */ 662 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 663 write_pnet(&ct->ct_net, net); 664 #ifdef CONFIG_NF_CONNTRACK_ZONES 665 if (zone) { 666 struct nf_conntrack_zone *nf_ct_zone; 667 668 nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, GFP_ATOMIC); 669 if (!nf_ct_zone) 670 goto out_free; 671 nf_ct_zone->id = zone; 672 } 673 #endif 674 /* 675 * changes to lookup keys must be done before setting refcnt to 1 676 */ 677 smp_wmb(); 678 atomic_set(&ct->ct_general.use, 1); 679 return ct; 680 681 #ifdef CONFIG_NF_CONNTRACK_ZONES 682 out_free: 683 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 684 return ERR_PTR(-ENOMEM); 685 #endif 686 } 687 688 struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone, 689 const struct nf_conntrack_tuple *orig, 690 const struct nf_conntrack_tuple *repl, 691 gfp_t gfp) 692 { 693 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 694 } 695 EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 696 697 void nf_conntrack_free(struct nf_conn *ct) 698 { 699 struct net *net = nf_ct_net(ct); 700 701 nf_ct_ext_destroy(ct); 702 atomic_dec(&net->ct.count); 703 nf_ct_ext_free(ct); 704 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 705 } 706 EXPORT_SYMBOL_GPL(nf_conntrack_free); 707 708 /* Allocate a new conntrack: we return -ENOMEM if classification 709 failed due to stress. Otherwise it really is unclassifiable. */ 710 static struct nf_conntrack_tuple_hash * 711 init_conntrack(struct net *net, struct nf_conn *tmpl, 712 const struct nf_conntrack_tuple *tuple, 713 struct nf_conntrack_l3proto *l3proto, 714 struct nf_conntrack_l4proto *l4proto, 715 struct sk_buff *skb, 716 unsigned int dataoff, u32 hash) 717 { 718 struct nf_conn *ct; 719 struct nf_conn_help *help; 720 struct nf_conntrack_tuple repl_tuple; 721 struct nf_conntrack_ecache *ecache; 722 struct nf_conntrack_expect *exp; 723 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 724 725 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 726 pr_debug("Can't invert tuple.\n"); 727 return NULL; 728 } 729 730 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 731 hash); 732 if (IS_ERR(ct)) { 733 pr_debug("Can't allocate conntrack.\n"); 734 return (struct nf_conntrack_tuple_hash *)ct; 735 } 736 737 if (!l4proto->new(ct, skb, dataoff)) { 738 nf_conntrack_free(ct); 739 pr_debug("init conntrack: can't track with proto module\n"); 740 return NULL; 741 } 742 743 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 744 745 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 746 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 747 ecache ? ecache->expmask : 0, 748 GFP_ATOMIC); 749 750 spin_lock_bh(&nf_conntrack_lock); 751 exp = nf_ct_find_expectation(net, zone, tuple); 752 if (exp) { 753 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 754 ct, exp); 755 /* Welcome, Mr. Bond. We've been expecting you... */ 756 __set_bit(IPS_EXPECTED_BIT, &ct->status); 757 ct->master = exp->master; 758 if (exp->helper) { 759 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 760 if (help) 761 rcu_assign_pointer(help->helper, exp->helper); 762 } 763 764 #ifdef CONFIG_NF_CONNTRACK_MARK 765 ct->mark = exp->master->mark; 766 #endif 767 #ifdef CONFIG_NF_CONNTRACK_SECMARK 768 ct->secmark = exp->master->secmark; 769 #endif 770 nf_conntrack_get(&ct->master->ct_general); 771 NF_CT_STAT_INC(net, expect_new); 772 } else { 773 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 774 NF_CT_STAT_INC(net, new); 775 } 776 777 /* Overload tuple linked list to put us in unconfirmed list. */ 778 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 779 &net->ct.unconfirmed); 780 781 spin_unlock_bh(&nf_conntrack_lock); 782 783 if (exp) { 784 if (exp->expectfn) 785 exp->expectfn(ct, exp); 786 nf_ct_expect_put(exp); 787 } 788 789 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 790 } 791 792 /* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 793 static inline struct nf_conn * 794 resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 795 struct sk_buff *skb, 796 unsigned int dataoff, 797 u_int16_t l3num, 798 u_int8_t protonum, 799 struct nf_conntrack_l3proto *l3proto, 800 struct nf_conntrack_l4proto *l4proto, 801 int *set_reply, 802 enum ip_conntrack_info *ctinfo) 803 { 804 struct nf_conntrack_tuple tuple; 805 struct nf_conntrack_tuple_hash *h; 806 struct nf_conn *ct; 807 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE; 808 u32 hash; 809 810 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 811 dataoff, l3num, protonum, &tuple, l3proto, 812 l4proto)) { 813 pr_debug("resolve_normal_ct: Can't get tuple\n"); 814 return NULL; 815 } 816 817 /* look for tuple match */ 818 hash = hash_conntrack_raw(&tuple, zone); 819 h = __nf_conntrack_find_get(net, zone, &tuple, hash); 820 if (!h) { 821 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 822 skb, dataoff, hash); 823 if (!h) 824 return NULL; 825 if (IS_ERR(h)) 826 return (void *)h; 827 } 828 ct = nf_ct_tuplehash_to_ctrack(h); 829 830 /* It exists; we have (non-exclusive) reference. */ 831 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 832 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY; 833 /* Please set reply bit if this packet OK */ 834 *set_reply = 1; 835 } else { 836 /* Once we've had two way comms, always ESTABLISHED. */ 837 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 838 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 839 *ctinfo = IP_CT_ESTABLISHED; 840 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 841 pr_debug("nf_conntrack_in: related packet for %p\n", 842 ct); 843 *ctinfo = IP_CT_RELATED; 844 } else { 845 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 846 *ctinfo = IP_CT_NEW; 847 } 848 *set_reply = 0; 849 } 850 skb->nfct = &ct->ct_general; 851 skb->nfctinfo = *ctinfo; 852 return ct; 853 } 854 855 unsigned int 856 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 857 struct sk_buff *skb) 858 { 859 struct nf_conn *ct, *tmpl = NULL; 860 enum ip_conntrack_info ctinfo; 861 struct nf_conntrack_l3proto *l3proto; 862 struct nf_conntrack_l4proto *l4proto; 863 unsigned int dataoff; 864 u_int8_t protonum; 865 int set_reply = 0; 866 int ret; 867 868 if (skb->nfct) { 869 /* Previously seen (loopback or untracked)? Ignore. */ 870 tmpl = (struct nf_conn *)skb->nfct; 871 if (!nf_ct_is_template(tmpl)) { 872 NF_CT_STAT_INC_ATOMIC(net, ignore); 873 return NF_ACCEPT; 874 } 875 skb->nfct = NULL; 876 } 877 878 /* rcu_read_lock()ed by nf_hook_slow */ 879 l3proto = __nf_ct_l3proto_find(pf); 880 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 881 &dataoff, &protonum); 882 if (ret <= 0) { 883 pr_debug("not prepared to track yet or error occured\n"); 884 NF_CT_STAT_INC_ATOMIC(net, error); 885 NF_CT_STAT_INC_ATOMIC(net, invalid); 886 ret = -ret; 887 goto out; 888 } 889 890 l4proto = __nf_ct_l4proto_find(pf, protonum); 891 892 /* It may be an special packet, error, unclean... 893 * inverse of the return code tells to the netfilter 894 * core what to do with the packet. */ 895 if (l4proto->error != NULL) { 896 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 897 pf, hooknum); 898 if (ret <= 0) { 899 NF_CT_STAT_INC_ATOMIC(net, error); 900 NF_CT_STAT_INC_ATOMIC(net, invalid); 901 ret = -ret; 902 goto out; 903 } 904 } 905 906 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 907 l3proto, l4proto, &set_reply, &ctinfo); 908 if (!ct) { 909 /* Not valid part of a connection */ 910 NF_CT_STAT_INC_ATOMIC(net, invalid); 911 ret = NF_ACCEPT; 912 goto out; 913 } 914 915 if (IS_ERR(ct)) { 916 /* Too stressed to deal. */ 917 NF_CT_STAT_INC_ATOMIC(net, drop); 918 ret = NF_DROP; 919 goto out; 920 } 921 922 NF_CT_ASSERT(skb->nfct); 923 924 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum); 925 if (ret <= 0) { 926 /* Invalid: inverse of the return code tells 927 * the netfilter core what to do */ 928 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 929 nf_conntrack_put(skb->nfct); 930 skb->nfct = NULL; 931 NF_CT_STAT_INC_ATOMIC(net, invalid); 932 if (ret == -NF_DROP) 933 NF_CT_STAT_INC_ATOMIC(net, drop); 934 ret = -ret; 935 goto out; 936 } 937 938 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 939 nf_conntrack_event_cache(IPCT_REPLY, ct); 940 out: 941 if (tmpl) 942 nf_ct_put(tmpl); 943 944 return ret; 945 } 946 EXPORT_SYMBOL_GPL(nf_conntrack_in); 947 948 bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 949 const struct nf_conntrack_tuple *orig) 950 { 951 bool ret; 952 953 rcu_read_lock(); 954 ret = nf_ct_invert_tuple(inverse, orig, 955 __nf_ct_l3proto_find(orig->src.l3num), 956 __nf_ct_l4proto_find(orig->src.l3num, 957 orig->dst.protonum)); 958 rcu_read_unlock(); 959 return ret; 960 } 961 EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 962 963 /* Alter reply tuple (maybe alter helper). This is for NAT, and is 964 implicitly racy: see __nf_conntrack_confirm */ 965 void nf_conntrack_alter_reply(struct nf_conn *ct, 966 const struct nf_conntrack_tuple *newreply) 967 { 968 struct nf_conn_help *help = nfct_help(ct); 969 970 /* Should be unconfirmed, so not in hash table yet */ 971 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 972 973 pr_debug("Altering reply tuple of %p to ", ct); 974 nf_ct_dump_tuple(newreply); 975 976 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 977 if (ct->master || (help && !hlist_empty(&help->expectations))) 978 return; 979 980 rcu_read_lock(); 981 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 982 rcu_read_unlock(); 983 } 984 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 985 986 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 987 void __nf_ct_refresh_acct(struct nf_conn *ct, 988 enum ip_conntrack_info ctinfo, 989 const struct sk_buff *skb, 990 unsigned long extra_jiffies, 991 int do_acct) 992 { 993 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 994 NF_CT_ASSERT(skb); 995 996 /* Only update if this is not a fixed timeout */ 997 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 998 goto acct; 999 1000 /* If not in hash table, timer will not be active yet */ 1001 if (!nf_ct_is_confirmed(ct)) { 1002 ct->timeout.expires = extra_jiffies; 1003 } else { 1004 unsigned long newtime = jiffies + extra_jiffies; 1005 1006 /* Only update the timeout if the new timeout is at least 1007 HZ jiffies from the old timeout. Need del_timer for race 1008 avoidance (may already be dying). */ 1009 if (newtime - ct->timeout.expires >= HZ) 1010 mod_timer_pending(&ct->timeout, newtime); 1011 } 1012 1013 acct: 1014 if (do_acct) { 1015 struct nf_conn_counter *acct; 1016 1017 acct = nf_conn_acct_find(ct); 1018 if (acct) { 1019 spin_lock_bh(&ct->lock); 1020 acct[CTINFO2DIR(ctinfo)].packets++; 1021 acct[CTINFO2DIR(ctinfo)].bytes += skb->len; 1022 spin_unlock_bh(&ct->lock); 1023 } 1024 } 1025 } 1026 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 1027 1028 bool __nf_ct_kill_acct(struct nf_conn *ct, 1029 enum ip_conntrack_info ctinfo, 1030 const struct sk_buff *skb, 1031 int do_acct) 1032 { 1033 if (do_acct) { 1034 struct nf_conn_counter *acct; 1035 1036 acct = nf_conn_acct_find(ct); 1037 if (acct) { 1038 spin_lock_bh(&ct->lock); 1039 acct[CTINFO2DIR(ctinfo)].packets++; 1040 acct[CTINFO2DIR(ctinfo)].bytes += 1041 skb->len - skb_network_offset(skb); 1042 spin_unlock_bh(&ct->lock); 1043 } 1044 } 1045 1046 if (del_timer(&ct->timeout)) { 1047 ct->timeout.function((unsigned long)ct); 1048 return true; 1049 } 1050 return false; 1051 } 1052 EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 1053 1054 #ifdef CONFIG_NF_CONNTRACK_ZONES 1055 static struct nf_ct_ext_type nf_ct_zone_extend __read_mostly = { 1056 .len = sizeof(struct nf_conntrack_zone), 1057 .align = __alignof__(struct nf_conntrack_zone), 1058 .id = NF_CT_EXT_ZONE, 1059 }; 1060 #endif 1061 1062 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 1063 1064 #include <linux/netfilter/nfnetlink.h> 1065 #include <linux/netfilter/nfnetlink_conntrack.h> 1066 #include <linux/mutex.h> 1067 1068 /* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 1069 * in ip_conntrack_core, since we don't want the protocols to autoload 1070 * or depend on ctnetlink */ 1071 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 1072 const struct nf_conntrack_tuple *tuple) 1073 { 1074 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port); 1075 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port); 1076 return 0; 1077 1078 nla_put_failure: 1079 return -1; 1080 } 1081 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 1082 1083 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 1084 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 1085 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 1086 }; 1087 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 1088 1089 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 1090 struct nf_conntrack_tuple *t) 1091 { 1092 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 1093 return -EINVAL; 1094 1095 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 1096 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 1097 1098 return 0; 1099 } 1100 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1101 1102 int nf_ct_port_nlattr_tuple_size(void) 1103 { 1104 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1105 } 1106 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1107 #endif 1108 1109 /* Used by ipt_REJECT and ip6t_REJECT. */ 1110 static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1111 { 1112 struct nf_conn *ct; 1113 enum ip_conntrack_info ctinfo; 1114 1115 /* This ICMP is in reverse direction to the packet which caused it */ 1116 ct = nf_ct_get(skb, &ctinfo); 1117 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1118 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY; 1119 else 1120 ctinfo = IP_CT_RELATED; 1121 1122 /* Attach to new skbuff, and increment count */ 1123 nskb->nfct = &ct->ct_general; 1124 nskb->nfctinfo = ctinfo; 1125 nf_conntrack_get(nskb->nfct); 1126 } 1127 1128 /* Bring out ya dead! */ 1129 static struct nf_conn * 1130 get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1131 void *data, unsigned int *bucket) 1132 { 1133 struct nf_conntrack_tuple_hash *h; 1134 struct nf_conn *ct; 1135 struct hlist_nulls_node *n; 1136 1137 spin_lock_bh(&nf_conntrack_lock); 1138 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1139 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1140 ct = nf_ct_tuplehash_to_ctrack(h); 1141 if (iter(ct, data)) 1142 goto found; 1143 } 1144 } 1145 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1146 ct = nf_ct_tuplehash_to_ctrack(h); 1147 if (iter(ct, data)) 1148 set_bit(IPS_DYING_BIT, &ct->status); 1149 } 1150 spin_unlock_bh(&nf_conntrack_lock); 1151 return NULL; 1152 found: 1153 atomic_inc(&ct->ct_general.use); 1154 spin_unlock_bh(&nf_conntrack_lock); 1155 return ct; 1156 } 1157 1158 void nf_ct_iterate_cleanup(struct net *net, 1159 int (*iter)(struct nf_conn *i, void *data), 1160 void *data) 1161 { 1162 struct nf_conn *ct; 1163 unsigned int bucket = 0; 1164 1165 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1166 /* Time to push up daises... */ 1167 if (del_timer(&ct->timeout)) 1168 death_by_timeout((unsigned long)ct); 1169 /* ... else the timer will get him soon. */ 1170 1171 nf_ct_put(ct); 1172 } 1173 } 1174 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1175 1176 struct __nf_ct_flush_report { 1177 u32 pid; 1178 int report; 1179 }; 1180 1181 static int kill_report(struct nf_conn *i, void *data) 1182 { 1183 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1184 1185 /* If we fail to deliver the event, death_by_timeout() will retry */ 1186 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1187 fr->pid, fr->report) < 0) 1188 return 1; 1189 1190 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1191 set_bit(IPS_DYING_BIT, &i->status); 1192 return 1; 1193 } 1194 1195 static int kill_all(struct nf_conn *i, void *data) 1196 { 1197 return 1; 1198 } 1199 1200 void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size) 1201 { 1202 if (vmalloced) 1203 vfree(hash); 1204 else 1205 free_pages((unsigned long)hash, 1206 get_order(sizeof(struct hlist_head) * size)); 1207 } 1208 EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1209 1210 void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1211 { 1212 struct __nf_ct_flush_report fr = { 1213 .pid = pid, 1214 .report = report, 1215 }; 1216 nf_ct_iterate_cleanup(net, kill_report, &fr); 1217 } 1218 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1219 1220 static void nf_ct_release_dying_list(struct net *net) 1221 { 1222 struct nf_conntrack_tuple_hash *h; 1223 struct nf_conn *ct; 1224 struct hlist_nulls_node *n; 1225 1226 spin_lock_bh(&nf_conntrack_lock); 1227 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1228 ct = nf_ct_tuplehash_to_ctrack(h); 1229 /* never fails to remove them, no listeners at this point */ 1230 nf_ct_kill(ct); 1231 } 1232 spin_unlock_bh(&nf_conntrack_lock); 1233 } 1234 1235 static int untrack_refs(void) 1236 { 1237 int cnt = 0, cpu; 1238 1239 for_each_possible_cpu(cpu) { 1240 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1241 1242 cnt += atomic_read(&ct->ct_general.use) - 1; 1243 } 1244 return cnt; 1245 } 1246 1247 static void nf_conntrack_cleanup_init_net(void) 1248 { 1249 while (untrack_refs() > 0) 1250 schedule(); 1251 1252 nf_conntrack_helper_fini(); 1253 nf_conntrack_proto_fini(); 1254 #ifdef CONFIG_NF_CONNTRACK_ZONES 1255 nf_ct_extend_unregister(&nf_ct_zone_extend); 1256 #endif 1257 } 1258 1259 static void nf_conntrack_cleanup_net(struct net *net) 1260 { 1261 i_see_dead_people: 1262 nf_ct_iterate_cleanup(net, kill_all, NULL); 1263 nf_ct_release_dying_list(net); 1264 if (atomic_read(&net->ct.count) != 0) { 1265 schedule(); 1266 goto i_see_dead_people; 1267 } 1268 1269 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1270 net->ct.htable_size); 1271 nf_conntrack_ecache_fini(net); 1272 nf_conntrack_acct_fini(net); 1273 nf_conntrack_expect_fini(net); 1274 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1275 kfree(net->ct.slabname); 1276 free_percpu(net->ct.stat); 1277 } 1278 1279 /* Mishearing the voices in his head, our hero wonders how he's 1280 supposed to kill the mall. */ 1281 void nf_conntrack_cleanup(struct net *net) 1282 { 1283 if (net_eq(net, &init_net)) 1284 rcu_assign_pointer(ip_ct_attach, NULL); 1285 1286 /* This makes sure all current packets have passed through 1287 netfilter framework. Roll on, two-stage module 1288 delete... */ 1289 synchronize_net(); 1290 1291 nf_conntrack_cleanup_net(net); 1292 1293 if (net_eq(net, &init_net)) { 1294 rcu_assign_pointer(nf_ct_destroy, NULL); 1295 nf_conntrack_cleanup_init_net(); 1296 } 1297 } 1298 1299 void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls) 1300 { 1301 struct hlist_nulls_head *hash; 1302 unsigned int nr_slots, i; 1303 size_t sz; 1304 1305 *vmalloced = 0; 1306 1307 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1308 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1309 sz = nr_slots * sizeof(struct hlist_nulls_head); 1310 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1311 get_order(sz)); 1312 if (!hash) { 1313 *vmalloced = 1; 1314 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1315 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL); 1316 } 1317 1318 if (hash && nulls) 1319 for (i = 0; i < nr_slots; i++) 1320 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1321 1322 return hash; 1323 } 1324 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1325 1326 int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1327 { 1328 int i, bucket, vmalloced, old_vmalloced; 1329 unsigned int hashsize, old_size; 1330 struct hlist_nulls_head *hash, *old_hash; 1331 struct nf_conntrack_tuple_hash *h; 1332 struct nf_conn *ct; 1333 1334 if (current->nsproxy->net_ns != &init_net) 1335 return -EOPNOTSUPP; 1336 1337 /* On boot, we can set this without any fancy locking. */ 1338 if (!nf_conntrack_htable_size) 1339 return param_set_uint(val, kp); 1340 1341 hashsize = simple_strtoul(val, NULL, 0); 1342 if (!hashsize) 1343 return -EINVAL; 1344 1345 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1); 1346 if (!hash) 1347 return -ENOMEM; 1348 1349 /* Lookups in the old hash might happen in parallel, which means we 1350 * might get false negatives during connection lookup. New connections 1351 * created because of a false negative won't make it into the hash 1352 * though since that required taking the lock. 1353 */ 1354 spin_lock_bh(&nf_conntrack_lock); 1355 for (i = 0; i < init_net.ct.htable_size; i++) { 1356 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1357 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1358 struct nf_conntrack_tuple_hash, hnnode); 1359 ct = nf_ct_tuplehash_to_ctrack(h); 1360 hlist_nulls_del_rcu(&h->hnnode); 1361 bucket = __hash_conntrack(&h->tuple, nf_ct_zone(ct), 1362 hashsize); 1363 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1364 } 1365 } 1366 old_size = init_net.ct.htable_size; 1367 old_vmalloced = init_net.ct.hash_vmalloc; 1368 old_hash = init_net.ct.hash; 1369 1370 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1371 init_net.ct.hash_vmalloc = vmalloced; 1372 init_net.ct.hash = hash; 1373 spin_unlock_bh(&nf_conntrack_lock); 1374 1375 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size); 1376 return 0; 1377 } 1378 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1379 1380 module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1381 &nf_conntrack_htable_size, 0600); 1382 1383 void nf_ct_untracked_status_or(unsigned long bits) 1384 { 1385 int cpu; 1386 1387 for_each_possible_cpu(cpu) 1388 per_cpu(nf_conntrack_untracked, cpu).status |= bits; 1389 } 1390 EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or); 1391 1392 static int nf_conntrack_init_init_net(void) 1393 { 1394 int max_factor = 8; 1395 int ret, cpu; 1396 1397 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1398 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1399 if (!nf_conntrack_htable_size) { 1400 nf_conntrack_htable_size 1401 = (((totalram_pages << PAGE_SHIFT) / 16384) 1402 / sizeof(struct hlist_head)); 1403 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1404 nf_conntrack_htable_size = 16384; 1405 if (nf_conntrack_htable_size < 32) 1406 nf_conntrack_htable_size = 32; 1407 1408 /* Use a max. factor of four by default to get the same max as 1409 * with the old struct list_heads. When a table size is given 1410 * we use the old value of 8 to avoid reducing the max. 1411 * entries. */ 1412 max_factor = 4; 1413 } 1414 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1415 1416 printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n", 1417 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1418 nf_conntrack_max); 1419 1420 ret = nf_conntrack_proto_init(); 1421 if (ret < 0) 1422 goto err_proto; 1423 1424 ret = nf_conntrack_helper_init(); 1425 if (ret < 0) 1426 goto err_helper; 1427 1428 #ifdef CONFIG_NF_CONNTRACK_ZONES 1429 ret = nf_ct_extend_register(&nf_ct_zone_extend); 1430 if (ret < 0) 1431 goto err_extend; 1432 #endif 1433 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1434 for_each_possible_cpu(cpu) { 1435 struct nf_conn *ct = &per_cpu(nf_conntrack_untracked, cpu); 1436 write_pnet(&ct->ct_net, &init_net); 1437 atomic_set(&ct->ct_general.use, 1); 1438 } 1439 /* - and look it like as a confirmed connection */ 1440 nf_ct_untracked_status_or(IPS_CONFIRMED | IPS_UNTRACKED); 1441 return 0; 1442 1443 #ifdef CONFIG_NF_CONNTRACK_ZONES 1444 err_extend: 1445 nf_conntrack_helper_fini(); 1446 #endif 1447 err_helper: 1448 nf_conntrack_proto_fini(); 1449 err_proto: 1450 return ret; 1451 } 1452 1453 /* 1454 * We need to use special "null" values, not used in hash table 1455 */ 1456 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1457 #define DYING_NULLS_VAL ((1<<30)+1) 1458 1459 static int nf_conntrack_init_net(struct net *net) 1460 { 1461 int ret; 1462 1463 atomic_set(&net->ct.count, 0); 1464 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1465 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1466 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1467 if (!net->ct.stat) { 1468 ret = -ENOMEM; 1469 goto err_stat; 1470 } 1471 1472 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1473 if (!net->ct.slabname) { 1474 ret = -ENOMEM; 1475 goto err_slabname; 1476 } 1477 1478 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1479 sizeof(struct nf_conn), 0, 1480 SLAB_DESTROY_BY_RCU, NULL); 1481 if (!net->ct.nf_conntrack_cachep) { 1482 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1483 ret = -ENOMEM; 1484 goto err_cache; 1485 } 1486 1487 net->ct.htable_size = nf_conntrack_htable_size; 1488 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1489 &net->ct.hash_vmalloc, 1); 1490 if (!net->ct.hash) { 1491 ret = -ENOMEM; 1492 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1493 goto err_hash; 1494 } 1495 ret = nf_conntrack_expect_init(net); 1496 if (ret < 0) 1497 goto err_expect; 1498 ret = nf_conntrack_acct_init(net); 1499 if (ret < 0) 1500 goto err_acct; 1501 ret = nf_conntrack_ecache_init(net); 1502 if (ret < 0) 1503 goto err_ecache; 1504 1505 return 0; 1506 1507 err_ecache: 1508 nf_conntrack_acct_fini(net); 1509 err_acct: 1510 nf_conntrack_expect_fini(net); 1511 err_expect: 1512 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1513 net->ct.htable_size); 1514 err_hash: 1515 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1516 err_cache: 1517 kfree(net->ct.slabname); 1518 err_slabname: 1519 free_percpu(net->ct.stat); 1520 err_stat: 1521 return ret; 1522 } 1523 1524 s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1525 enum ip_conntrack_dir dir, 1526 u32 seq); 1527 EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1528 1529 int nf_conntrack_init(struct net *net) 1530 { 1531 int ret; 1532 1533 if (net_eq(net, &init_net)) { 1534 ret = nf_conntrack_init_init_net(); 1535 if (ret < 0) 1536 goto out_init_net; 1537 } 1538 ret = nf_conntrack_init_net(net); 1539 if (ret < 0) 1540 goto out_net; 1541 1542 if (net_eq(net, &init_net)) { 1543 /* For use by REJECT target */ 1544 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach); 1545 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack); 1546 1547 /* Howto get NAT offsets */ 1548 rcu_assign_pointer(nf_ct_nat_offset, NULL); 1549 } 1550 return 0; 1551 1552 out_net: 1553 if (net_eq(net, &init_net)) 1554 nf_conntrack_cleanup_init_net(); 1555 out_init_net: 1556 return ret; 1557 } 1558