1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Connection state tracking for netfilter. This is separated from, 3 but required by, the NAT layer; it can also be used by an iptables 4 extension. */ 5 6 /* (C) 1999-2001 Paul `Rusty' Russell 7 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> 8 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> 9 * (C) 2005-2012 Patrick McHardy <kaber@trash.net> 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 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/siphash.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_bpf.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_conntrack_synproxy.h> 50 #include <net/netfilter/nf_nat.h> 51 #include <net/netfilter/nf_nat_helper.h> 52 #include <net/netns/hash.h> 53 #include <net/ip.h> 54 55 #include "nf_internals.h" 56 57 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS]; 58 EXPORT_SYMBOL_GPL(nf_conntrack_locks); 59 60 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock); 61 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock); 62 63 struct hlist_nulls_head *nf_conntrack_hash __read_mostly; 64 EXPORT_SYMBOL_GPL(nf_conntrack_hash); 65 66 struct conntrack_gc_work { 67 struct delayed_work dwork; 68 u32 next_bucket; 69 u32 avg_timeout; 70 u32 start_time; 71 bool exiting; 72 bool early_drop; 73 }; 74 75 static __read_mostly struct kmem_cache *nf_conntrack_cachep; 76 static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock); 77 static __read_mostly bool nf_conntrack_locks_all; 78 79 /* serialize hash resizes and nf_ct_iterate_cleanup */ 80 static DEFINE_MUTEX(nf_conntrack_mutex); 81 82 #define GC_SCAN_INTERVAL_MAX (60ul * HZ) 83 #define GC_SCAN_INTERVAL_MIN (1ul * HZ) 84 85 /* clamp timeouts to this value (TCP unacked) */ 86 #define GC_SCAN_INTERVAL_CLAMP (300ul * HZ) 87 88 /* large initial bias so that we don't scan often just because we have 89 * three entries with a 1s timeout. 90 */ 91 #define GC_SCAN_INTERVAL_INIT INT_MAX 92 93 #define GC_SCAN_MAX_DURATION msecs_to_jiffies(10) 94 #define GC_SCAN_EXPIRED_MAX (64000u / HZ) 95 96 #define MIN_CHAINLEN 8u 97 #define MAX_CHAINLEN (32u - MIN_CHAINLEN) 98 99 static struct conntrack_gc_work conntrack_gc_work; 100 101 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock) 102 { 103 /* 1) Acquire the lock */ 104 spin_lock(lock); 105 106 /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics 107 * It pairs with the smp_store_release() in nf_conntrack_all_unlock() 108 */ 109 if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false)) 110 return; 111 112 /* fast path failed, unlock */ 113 spin_unlock(lock); 114 115 /* Slow path 1) get global lock */ 116 spin_lock(&nf_conntrack_locks_all_lock); 117 118 /* Slow path 2) get the lock we want */ 119 spin_lock(lock); 120 121 /* Slow path 3) release the global lock */ 122 spin_unlock(&nf_conntrack_locks_all_lock); 123 } 124 EXPORT_SYMBOL_GPL(nf_conntrack_lock); 125 126 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2) 127 { 128 h1 %= CONNTRACK_LOCKS; 129 h2 %= CONNTRACK_LOCKS; 130 spin_unlock(&nf_conntrack_locks[h1]); 131 if (h1 != h2) 132 spin_unlock(&nf_conntrack_locks[h2]); 133 } 134 135 /* return true if we need to recompute hashes (in case hash table was resized) */ 136 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1, 137 unsigned int h2, unsigned int sequence) 138 { 139 h1 %= CONNTRACK_LOCKS; 140 h2 %= CONNTRACK_LOCKS; 141 if (h1 <= h2) { 142 nf_conntrack_lock(&nf_conntrack_locks[h1]); 143 if (h1 != h2) 144 spin_lock_nested(&nf_conntrack_locks[h2], 145 SINGLE_DEPTH_NESTING); 146 } else { 147 nf_conntrack_lock(&nf_conntrack_locks[h2]); 148 spin_lock_nested(&nf_conntrack_locks[h1], 149 SINGLE_DEPTH_NESTING); 150 } 151 if (read_seqcount_retry(&nf_conntrack_generation, sequence)) { 152 nf_conntrack_double_unlock(h1, h2); 153 return true; 154 } 155 return false; 156 } 157 158 static void nf_conntrack_all_lock(void) 159 __acquires(&nf_conntrack_locks_all_lock) 160 { 161 int i; 162 163 spin_lock(&nf_conntrack_locks_all_lock); 164 165 /* For nf_contrack_locks_all, only the latest time when another 166 * CPU will see an update is controlled, by the "release" of the 167 * spin_lock below. 168 * The earliest time is not controlled, an thus KCSAN could detect 169 * a race when nf_conntract_lock() reads the variable. 170 * WRITE_ONCE() is used to ensure the compiler will not 171 * optimize the write. 172 */ 173 WRITE_ONCE(nf_conntrack_locks_all, true); 174 175 for (i = 0; i < CONNTRACK_LOCKS; i++) { 176 spin_lock(&nf_conntrack_locks[i]); 177 178 /* This spin_unlock provides the "release" to ensure that 179 * nf_conntrack_locks_all==true is visible to everyone that 180 * acquired spin_lock(&nf_conntrack_locks[]). 181 */ 182 spin_unlock(&nf_conntrack_locks[i]); 183 } 184 } 185 186 static void nf_conntrack_all_unlock(void) 187 __releases(&nf_conntrack_locks_all_lock) 188 { 189 /* All prior stores must be complete before we clear 190 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock() 191 * might observe the false value but not the entire 192 * critical section. 193 * It pairs with the smp_load_acquire() in nf_conntrack_lock() 194 */ 195 smp_store_release(&nf_conntrack_locks_all, false); 196 spin_unlock(&nf_conntrack_locks_all_lock); 197 } 198 199 unsigned int nf_conntrack_htable_size __read_mostly; 200 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 201 202 unsigned int nf_conntrack_max __read_mostly; 203 EXPORT_SYMBOL_GPL(nf_conntrack_max); 204 seqcount_spinlock_t nf_conntrack_generation __read_mostly; 205 static siphash_aligned_key_t nf_conntrack_hash_rnd; 206 207 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, 208 unsigned int zoneid, 209 const struct net *net) 210 { 211 struct { 212 struct nf_conntrack_man src; 213 union nf_inet_addr dst_addr; 214 unsigned int zone; 215 u32 net_mix; 216 u16 dport; 217 u16 proto; 218 } __aligned(SIPHASH_ALIGNMENT) combined; 219 220 get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd)); 221 222 memset(&combined, 0, sizeof(combined)); 223 224 /* The direction must be ignored, so handle usable members manually. */ 225 combined.src = tuple->src; 226 combined.dst_addr = tuple->dst.u3; 227 combined.zone = zoneid; 228 combined.net_mix = net_hash_mix(net); 229 combined.dport = (__force __u16)tuple->dst.u.all; 230 combined.proto = tuple->dst.protonum; 231 232 return (u32)siphash(&combined, sizeof(combined), &nf_conntrack_hash_rnd); 233 } 234 235 static u32 scale_hash(u32 hash) 236 { 237 return reciprocal_scale(hash, nf_conntrack_htable_size); 238 } 239 240 static u32 __hash_conntrack(const struct net *net, 241 const struct nf_conntrack_tuple *tuple, 242 unsigned int zoneid, 243 unsigned int size) 244 { 245 return reciprocal_scale(hash_conntrack_raw(tuple, zoneid, net), size); 246 } 247 248 static u32 hash_conntrack(const struct net *net, 249 const struct nf_conntrack_tuple *tuple, 250 unsigned int zoneid) 251 { 252 return scale_hash(hash_conntrack_raw(tuple, zoneid, net)); 253 } 254 255 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb, 256 unsigned int dataoff, 257 struct nf_conntrack_tuple *tuple) 258 { struct { 259 __be16 sport; 260 __be16 dport; 261 } _inet_hdr, *inet_hdr; 262 263 /* Actually only need first 4 bytes to get ports. */ 264 inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr); 265 if (!inet_hdr) 266 return false; 267 268 tuple->src.u.udp.port = inet_hdr->sport; 269 tuple->dst.u.udp.port = inet_hdr->dport; 270 return true; 271 } 272 273 static bool 274 nf_ct_get_tuple(const struct sk_buff *skb, 275 unsigned int nhoff, 276 unsigned int dataoff, 277 u_int16_t l3num, 278 u_int8_t protonum, 279 struct net *net, 280 struct nf_conntrack_tuple *tuple) 281 { 282 unsigned int size; 283 const __be32 *ap; 284 __be32 _addrs[8]; 285 286 memset(tuple, 0, sizeof(*tuple)); 287 288 tuple->src.l3num = l3num; 289 switch (l3num) { 290 case NFPROTO_IPV4: 291 nhoff += offsetof(struct iphdr, saddr); 292 size = 2 * sizeof(__be32); 293 break; 294 case NFPROTO_IPV6: 295 nhoff += offsetof(struct ipv6hdr, saddr); 296 size = sizeof(_addrs); 297 break; 298 default: 299 return true; 300 } 301 302 ap = skb_header_pointer(skb, nhoff, size, _addrs); 303 if (!ap) 304 return false; 305 306 switch (l3num) { 307 case NFPROTO_IPV4: 308 tuple->src.u3.ip = ap[0]; 309 tuple->dst.u3.ip = ap[1]; 310 break; 311 case NFPROTO_IPV6: 312 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6)); 313 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6)); 314 break; 315 } 316 317 tuple->dst.protonum = protonum; 318 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 319 320 switch (protonum) { 321 #if IS_ENABLED(CONFIG_IPV6) 322 case IPPROTO_ICMPV6: 323 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple); 324 #endif 325 case IPPROTO_ICMP: 326 return icmp_pkt_to_tuple(skb, dataoff, net, tuple); 327 #ifdef CONFIG_NF_CT_PROTO_GRE 328 case IPPROTO_GRE: 329 return gre_pkt_to_tuple(skb, dataoff, net, tuple); 330 #endif 331 case IPPROTO_TCP: 332 case IPPROTO_UDP: /* fallthrough */ 333 return nf_ct_get_tuple_ports(skb, dataoff, tuple); 334 #ifdef CONFIG_NF_CT_PROTO_UDPLITE 335 case IPPROTO_UDPLITE: 336 return nf_ct_get_tuple_ports(skb, dataoff, tuple); 337 #endif 338 #ifdef CONFIG_NF_CT_PROTO_SCTP 339 case IPPROTO_SCTP: 340 return nf_ct_get_tuple_ports(skb, dataoff, tuple); 341 #endif 342 #ifdef CONFIG_NF_CT_PROTO_DCCP 343 case IPPROTO_DCCP: 344 return nf_ct_get_tuple_ports(skb, dataoff, tuple); 345 #endif 346 default: 347 break; 348 } 349 350 return true; 351 } 352 353 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, 354 u_int8_t *protonum) 355 { 356 int dataoff = -1; 357 const struct iphdr *iph; 358 struct iphdr _iph; 359 360 iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); 361 if (!iph) 362 return -1; 363 364 /* Conntrack defragments packets, we might still see fragments 365 * inside ICMP packets though. 366 */ 367 if (iph->frag_off & htons(IP_OFFSET)) 368 return -1; 369 370 dataoff = nhoff + (iph->ihl << 2); 371 *protonum = iph->protocol; 372 373 /* Check bogus IP headers */ 374 if (dataoff > skb->len) { 375 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n", 376 nhoff, iph->ihl << 2, skb->len); 377 return -1; 378 } 379 return dataoff; 380 } 381 382 #if IS_ENABLED(CONFIG_IPV6) 383 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, 384 u8 *protonum) 385 { 386 int protoff = -1; 387 unsigned int extoff = nhoff + sizeof(struct ipv6hdr); 388 __be16 frag_off; 389 u8 nexthdr; 390 391 if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr), 392 &nexthdr, sizeof(nexthdr)) != 0) { 393 pr_debug("can't get nexthdr\n"); 394 return -1; 395 } 396 protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off); 397 /* 398 * (protoff == skb->len) means the packet has not data, just 399 * IPv6 and possibly extensions headers, but it is tracked anyway 400 */ 401 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) { 402 pr_debug("can't find proto in pkt\n"); 403 return -1; 404 } 405 406 *protonum = nexthdr; 407 return protoff; 408 } 409 #endif 410 411 static int get_l4proto(const struct sk_buff *skb, 412 unsigned int nhoff, u8 pf, u8 *l4num) 413 { 414 switch (pf) { 415 case NFPROTO_IPV4: 416 return ipv4_get_l4proto(skb, nhoff, l4num); 417 #if IS_ENABLED(CONFIG_IPV6) 418 case NFPROTO_IPV6: 419 return ipv6_get_l4proto(skb, nhoff, l4num); 420 #endif 421 default: 422 *l4num = 0; 423 break; 424 } 425 return -1; 426 } 427 428 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 429 u_int16_t l3num, 430 struct net *net, struct nf_conntrack_tuple *tuple) 431 { 432 u8 protonum; 433 int protoff; 434 435 protoff = get_l4proto(skb, nhoff, l3num, &protonum); 436 if (protoff <= 0) 437 return false; 438 439 return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple); 440 } 441 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 442 443 bool 444 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 445 const struct nf_conntrack_tuple *orig) 446 { 447 memset(inverse, 0, sizeof(*inverse)); 448 449 inverse->src.l3num = orig->src.l3num; 450 451 switch (orig->src.l3num) { 452 case NFPROTO_IPV4: 453 inverse->src.u3.ip = orig->dst.u3.ip; 454 inverse->dst.u3.ip = orig->src.u3.ip; 455 break; 456 case NFPROTO_IPV6: 457 inverse->src.u3.in6 = orig->dst.u3.in6; 458 inverse->dst.u3.in6 = orig->src.u3.in6; 459 break; 460 default: 461 break; 462 } 463 464 inverse->dst.dir = !orig->dst.dir; 465 466 inverse->dst.protonum = orig->dst.protonum; 467 468 switch (orig->dst.protonum) { 469 case IPPROTO_ICMP: 470 return nf_conntrack_invert_icmp_tuple(inverse, orig); 471 #if IS_ENABLED(CONFIG_IPV6) 472 case IPPROTO_ICMPV6: 473 return nf_conntrack_invert_icmpv6_tuple(inverse, orig); 474 #endif 475 } 476 477 inverse->src.u.all = orig->dst.u.all; 478 inverse->dst.u.all = orig->src.u.all; 479 return true; 480 } 481 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 482 483 /* Generate a almost-unique pseudo-id for a given conntrack. 484 * 485 * intentionally doesn't re-use any of the seeds used for hash 486 * table location, we assume id gets exposed to userspace. 487 * 488 * Following nf_conn items do not change throughout lifetime 489 * of the nf_conn: 490 * 491 * 1. nf_conn address 492 * 2. nf_conn->master address (normally NULL) 493 * 3. the associated net namespace 494 * 4. the original direction tuple 495 */ 496 u32 nf_ct_get_id(const struct nf_conn *ct) 497 { 498 static siphash_aligned_key_t ct_id_seed; 499 unsigned long a, b, c, d; 500 501 net_get_random_once(&ct_id_seed, sizeof(ct_id_seed)); 502 503 a = (unsigned long)ct; 504 b = (unsigned long)ct->master; 505 c = (unsigned long)nf_ct_net(ct); 506 d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 507 sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple), 508 &ct_id_seed); 509 #ifdef CONFIG_64BIT 510 return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed); 511 #else 512 return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed); 513 #endif 514 } 515 EXPORT_SYMBOL_GPL(nf_ct_get_id); 516 517 static void 518 clean_from_lists(struct nf_conn *ct) 519 { 520 pr_debug("clean_from_lists(%p)\n", ct); 521 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 522 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 523 524 /* Destroy all pending expectations */ 525 nf_ct_remove_expectations(ct); 526 } 527 528 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK) 529 530 /* Released via nf_ct_destroy() */ 531 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 532 const struct nf_conntrack_zone *zone, 533 gfp_t flags) 534 { 535 struct nf_conn *tmpl, *p; 536 537 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) { 538 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags); 539 if (!tmpl) 540 return NULL; 541 542 p = tmpl; 543 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p); 544 if (tmpl != p) { 545 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p); 546 tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p; 547 } 548 } else { 549 tmpl = kzalloc(sizeof(*tmpl), flags); 550 if (!tmpl) 551 return NULL; 552 } 553 554 tmpl->status = IPS_TEMPLATE; 555 write_pnet(&tmpl->ct_net, net); 556 nf_ct_zone_add(tmpl, zone); 557 refcount_set(&tmpl->ct_general.use, 1); 558 559 return tmpl; 560 } 561 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc); 562 563 void nf_ct_tmpl_free(struct nf_conn *tmpl) 564 { 565 kfree(tmpl->ext); 566 567 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) 568 kfree((char *)tmpl - tmpl->proto.tmpl_padto); 569 else 570 kfree(tmpl); 571 } 572 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free); 573 574 static void destroy_gre_conntrack(struct nf_conn *ct) 575 { 576 #ifdef CONFIG_NF_CT_PROTO_GRE 577 struct nf_conn *master = ct->master; 578 579 if (master) 580 nf_ct_gre_keymap_destroy(master); 581 #endif 582 } 583 584 void nf_ct_destroy(struct nf_conntrack *nfct) 585 { 586 struct nf_conn *ct = (struct nf_conn *)nfct; 587 588 pr_debug("%s(%p)\n", __func__, ct); 589 WARN_ON(refcount_read(&nfct->use) != 0); 590 591 if (unlikely(nf_ct_is_template(ct))) { 592 nf_ct_tmpl_free(ct); 593 return; 594 } 595 596 if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE)) 597 destroy_gre_conntrack(ct); 598 599 /* Expectations will have been removed in clean_from_lists, 600 * except TFTP can create an expectation on the first packet, 601 * before connection is in the list, so we need to clean here, 602 * too. 603 */ 604 nf_ct_remove_expectations(ct); 605 606 if (ct->master) 607 nf_ct_put(ct->master); 608 609 pr_debug("%s: returning ct=%p to slab\n", __func__, ct); 610 nf_conntrack_free(ct); 611 } 612 EXPORT_SYMBOL(nf_ct_destroy); 613 614 static void __nf_ct_delete_from_lists(struct nf_conn *ct) 615 { 616 struct net *net = nf_ct_net(ct); 617 unsigned int hash, reply_hash; 618 unsigned int sequence; 619 620 do { 621 sequence = read_seqcount_begin(&nf_conntrack_generation); 622 hash = hash_conntrack(net, 623 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 624 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL)); 625 reply_hash = hash_conntrack(net, 626 &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 627 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); 628 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); 629 630 clean_from_lists(ct); 631 nf_conntrack_double_unlock(hash, reply_hash); 632 } 633 634 static void nf_ct_delete_from_lists(struct nf_conn *ct) 635 { 636 nf_ct_helper_destroy(ct); 637 local_bh_disable(); 638 639 __nf_ct_delete_from_lists(ct); 640 641 local_bh_enable(); 642 } 643 644 static void nf_ct_add_to_ecache_list(struct nf_conn *ct) 645 { 646 #ifdef CONFIG_NF_CONNTRACK_EVENTS 647 struct nf_conntrack_net *cnet = nf_ct_pernet(nf_ct_net(ct)); 648 649 spin_lock(&cnet->ecache.dying_lock); 650 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 651 &cnet->ecache.dying_list); 652 spin_unlock(&cnet->ecache.dying_lock); 653 #endif 654 } 655 656 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report) 657 { 658 struct nf_conn_tstamp *tstamp; 659 struct net *net; 660 661 if (test_and_set_bit(IPS_DYING_BIT, &ct->status)) 662 return false; 663 664 tstamp = nf_conn_tstamp_find(ct); 665 if (tstamp) { 666 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 667 668 tstamp->stop = ktime_get_real_ns(); 669 if (timeout < 0) 670 tstamp->stop -= jiffies_to_nsecs(-timeout); 671 } 672 673 if (nf_conntrack_event_report(IPCT_DESTROY, ct, 674 portid, report) < 0) { 675 /* destroy event was not delivered. nf_ct_put will 676 * be done by event cache worker on redelivery. 677 */ 678 nf_ct_helper_destroy(ct); 679 local_bh_disable(); 680 __nf_ct_delete_from_lists(ct); 681 nf_ct_add_to_ecache_list(ct); 682 local_bh_enable(); 683 684 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL); 685 return false; 686 } 687 688 net = nf_ct_net(ct); 689 if (nf_conntrack_ecache_dwork_pending(net)) 690 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT); 691 nf_ct_delete_from_lists(ct); 692 nf_ct_put(ct); 693 return true; 694 } 695 EXPORT_SYMBOL_GPL(nf_ct_delete); 696 697 static inline bool 698 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h, 699 const struct nf_conntrack_tuple *tuple, 700 const struct nf_conntrack_zone *zone, 701 const struct net *net) 702 { 703 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); 704 705 /* A conntrack can be recreated with the equal tuple, 706 * so we need to check that the conntrack is confirmed 707 */ 708 return nf_ct_tuple_equal(tuple, &h->tuple) && 709 nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) && 710 nf_ct_is_confirmed(ct) && 711 net_eq(net, nf_ct_net(ct)); 712 } 713 714 static inline bool 715 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2) 716 { 717 return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 718 &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) && 719 nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple, 720 &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) && 721 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) && 722 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) && 723 net_eq(nf_ct_net(ct1), nf_ct_net(ct2)); 724 } 725 726 /* caller must hold rcu readlock and none of the nf_conntrack_locks */ 727 static void nf_ct_gc_expired(struct nf_conn *ct) 728 { 729 if (!refcount_inc_not_zero(&ct->ct_general.use)) 730 return; 731 732 if (nf_ct_should_gc(ct)) 733 nf_ct_kill(ct); 734 735 nf_ct_put(ct); 736 } 737 738 /* 739 * Warning : 740 * - Caller must take a reference on returned object 741 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 742 */ 743 static struct nf_conntrack_tuple_hash * 744 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone, 745 const struct nf_conntrack_tuple *tuple, u32 hash) 746 { 747 struct nf_conntrack_tuple_hash *h; 748 struct hlist_nulls_head *ct_hash; 749 struct hlist_nulls_node *n; 750 unsigned int bucket, hsize; 751 752 begin: 753 nf_conntrack_get_ht(&ct_hash, &hsize); 754 bucket = reciprocal_scale(hash, hsize); 755 756 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) { 757 struct nf_conn *ct; 758 759 ct = nf_ct_tuplehash_to_ctrack(h); 760 if (nf_ct_is_expired(ct)) { 761 nf_ct_gc_expired(ct); 762 continue; 763 } 764 765 if (nf_ct_key_equal(h, tuple, zone, net)) 766 return h; 767 } 768 /* 769 * if the nulls value we got at the end of this lookup is 770 * not the expected one, we must restart lookup. 771 * We probably met an item that was moved to another chain. 772 */ 773 if (get_nulls_value(n) != bucket) { 774 NF_CT_STAT_INC_ATOMIC(net, search_restart); 775 goto begin; 776 } 777 778 return NULL; 779 } 780 781 /* Find a connection corresponding to a tuple. */ 782 static struct nf_conntrack_tuple_hash * 783 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, 784 const struct nf_conntrack_tuple *tuple, u32 hash) 785 { 786 struct nf_conntrack_tuple_hash *h; 787 struct nf_conn *ct; 788 789 rcu_read_lock(); 790 791 h = ____nf_conntrack_find(net, zone, tuple, hash); 792 if (h) { 793 /* We have a candidate that matches the tuple we're interested 794 * in, try to obtain a reference and re-check tuple 795 */ 796 ct = nf_ct_tuplehash_to_ctrack(h); 797 if (likely(refcount_inc_not_zero(&ct->ct_general.use))) { 798 if (likely(nf_ct_key_equal(h, tuple, zone, net))) 799 goto found; 800 801 /* TYPESAFE_BY_RCU recycled the candidate */ 802 nf_ct_put(ct); 803 } 804 805 h = NULL; 806 } 807 found: 808 rcu_read_unlock(); 809 810 return h; 811 } 812 813 struct nf_conntrack_tuple_hash * 814 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, 815 const struct nf_conntrack_tuple *tuple) 816 { 817 unsigned int rid, zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL); 818 struct nf_conntrack_tuple_hash *thash; 819 820 thash = __nf_conntrack_find_get(net, zone, tuple, 821 hash_conntrack_raw(tuple, zone_id, net)); 822 823 if (thash) 824 return thash; 825 826 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY); 827 if (rid != zone_id) 828 return __nf_conntrack_find_get(net, zone, tuple, 829 hash_conntrack_raw(tuple, rid, net)); 830 return thash; 831 } 832 EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 833 834 static void __nf_conntrack_hash_insert(struct nf_conn *ct, 835 unsigned int hash, 836 unsigned int reply_hash) 837 { 838 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 839 &nf_conntrack_hash[hash]); 840 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 841 &nf_conntrack_hash[reply_hash]); 842 } 843 844 static bool nf_ct_ext_valid_pre(const struct nf_ct_ext *ext) 845 { 846 /* if ext->gen_id is not equal to nf_conntrack_ext_genid, some extensions 847 * may contain stale pointers to e.g. helper that has been removed. 848 * 849 * The helper can't clear this because the nf_conn object isn't in 850 * any hash and synchronize_rcu() isn't enough because associated skb 851 * might sit in a queue. 852 */ 853 return !ext || ext->gen_id == atomic_read(&nf_conntrack_ext_genid); 854 } 855 856 static bool nf_ct_ext_valid_post(struct nf_ct_ext *ext) 857 { 858 if (!ext) 859 return true; 860 861 if (ext->gen_id != atomic_read(&nf_conntrack_ext_genid)) 862 return false; 863 864 /* inserted into conntrack table, nf_ct_iterate_cleanup() 865 * will find it. Disable nf_ct_ext_find() id check. 866 */ 867 WRITE_ONCE(ext->gen_id, 0); 868 return true; 869 } 870 871 int 872 nf_conntrack_hash_check_insert(struct nf_conn *ct) 873 { 874 const struct nf_conntrack_zone *zone; 875 struct net *net = nf_ct_net(ct); 876 unsigned int hash, reply_hash; 877 struct nf_conntrack_tuple_hash *h; 878 struct hlist_nulls_node *n; 879 unsigned int max_chainlen; 880 unsigned int chainlen = 0; 881 unsigned int sequence; 882 int err = -EEXIST; 883 884 zone = nf_ct_zone(ct); 885 886 if (!nf_ct_ext_valid_pre(ct->ext)) { 887 NF_CT_STAT_INC(net, insert_failed); 888 return -ETIMEDOUT; 889 } 890 891 local_bh_disable(); 892 do { 893 sequence = read_seqcount_begin(&nf_conntrack_generation); 894 hash = hash_conntrack(net, 895 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 896 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL)); 897 reply_hash = hash_conntrack(net, 898 &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 899 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); 900 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); 901 902 max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN); 903 904 /* See if there's one in the list already, including reverse */ 905 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) { 906 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 907 zone, net)) 908 goto out; 909 910 if (chainlen++ > max_chainlen) 911 goto chaintoolong; 912 } 913 914 chainlen = 0; 915 916 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) { 917 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 918 zone, net)) 919 goto out; 920 if (chainlen++ > max_chainlen) 921 goto chaintoolong; 922 } 923 924 smp_wmb(); 925 /* The caller holds a reference to this object */ 926 refcount_set(&ct->ct_general.use, 2); 927 __nf_conntrack_hash_insert(ct, hash, reply_hash); 928 nf_conntrack_double_unlock(hash, reply_hash); 929 NF_CT_STAT_INC(net, insert); 930 local_bh_enable(); 931 932 if (!nf_ct_ext_valid_post(ct->ext)) { 933 nf_ct_kill(ct); 934 NF_CT_STAT_INC(net, drop); 935 return -ETIMEDOUT; 936 } 937 938 return 0; 939 chaintoolong: 940 NF_CT_STAT_INC(net, chaintoolong); 941 err = -ENOSPC; 942 out: 943 nf_conntrack_double_unlock(hash, reply_hash); 944 local_bh_enable(); 945 return err; 946 } 947 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); 948 949 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets, 950 unsigned int bytes) 951 { 952 struct nf_conn_acct *acct; 953 954 acct = nf_conn_acct_find(ct); 955 if (acct) { 956 struct nf_conn_counter *counter = acct->counter; 957 958 atomic64_add(packets, &counter[dir].packets); 959 atomic64_add(bytes, &counter[dir].bytes); 960 } 961 } 962 EXPORT_SYMBOL_GPL(nf_ct_acct_add); 963 964 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 965 const struct nf_conn *loser_ct) 966 { 967 struct nf_conn_acct *acct; 968 969 acct = nf_conn_acct_find(loser_ct); 970 if (acct) { 971 struct nf_conn_counter *counter = acct->counter; 972 unsigned int bytes; 973 974 /* u32 should be fine since we must have seen one packet. */ 975 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes); 976 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes); 977 } 978 } 979 980 static void __nf_conntrack_insert_prepare(struct nf_conn *ct) 981 { 982 struct nf_conn_tstamp *tstamp; 983 984 refcount_inc(&ct->ct_general.use); 985 986 /* set conntrack timestamp, if enabled. */ 987 tstamp = nf_conn_tstamp_find(ct); 988 if (tstamp) 989 tstamp->start = ktime_get_real_ns(); 990 } 991 992 /* caller must hold locks to prevent concurrent changes */ 993 static int __nf_ct_resolve_clash(struct sk_buff *skb, 994 struct nf_conntrack_tuple_hash *h) 995 { 996 /* This is the conntrack entry already in hashes that won race. */ 997 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); 998 enum ip_conntrack_info ctinfo; 999 struct nf_conn *loser_ct; 1000 1001 loser_ct = nf_ct_get(skb, &ctinfo); 1002 1003 if (nf_ct_is_dying(ct)) 1004 return NF_DROP; 1005 1006 if (((ct->status & IPS_NAT_DONE_MASK) == 0) || 1007 nf_ct_match(ct, loser_ct)) { 1008 struct net *net = nf_ct_net(ct); 1009 1010 nf_conntrack_get(&ct->ct_general); 1011 1012 nf_ct_acct_merge(ct, ctinfo, loser_ct); 1013 nf_ct_put(loser_ct); 1014 nf_ct_set(skb, ct, ctinfo); 1015 1016 NF_CT_STAT_INC(net, clash_resolve); 1017 return NF_ACCEPT; 1018 } 1019 1020 return NF_DROP; 1021 } 1022 1023 /** 1024 * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry 1025 * 1026 * @skb: skb that causes the collision 1027 * @repl_idx: hash slot for reply direction 1028 * 1029 * Called when origin or reply direction had a clash. 1030 * The skb can be handled without packet drop provided the reply direction 1031 * is unique or there the existing entry has the identical tuple in both 1032 * directions. 1033 * 1034 * Caller must hold conntrack table locks to prevent concurrent updates. 1035 * 1036 * Returns NF_DROP if the clash could not be handled. 1037 */ 1038 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx) 1039 { 1040 struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb); 1041 const struct nf_conntrack_zone *zone; 1042 struct nf_conntrack_tuple_hash *h; 1043 struct hlist_nulls_node *n; 1044 struct net *net; 1045 1046 zone = nf_ct_zone(loser_ct); 1047 net = nf_ct_net(loser_ct); 1048 1049 /* Reply direction must never result in a clash, unless both origin 1050 * and reply tuples are identical. 1051 */ 1052 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) { 1053 if (nf_ct_key_equal(h, 1054 &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple, 1055 zone, net)) 1056 return __nf_ct_resolve_clash(skb, h); 1057 } 1058 1059 /* We want the clashing entry to go away real soon: 1 second timeout. */ 1060 WRITE_ONCE(loser_ct->timeout, nfct_time_stamp + HZ); 1061 1062 /* IPS_NAT_CLASH removes the entry automatically on the first 1063 * reply. Also prevents UDP tracker from moving the entry to 1064 * ASSURED state, i.e. the entry can always be evicted under 1065 * pressure. 1066 */ 1067 loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH; 1068 1069 __nf_conntrack_insert_prepare(loser_ct); 1070 1071 /* fake add for ORIGINAL dir: we want lookups to only find the entry 1072 * already in the table. This also hides the clashing entry from 1073 * ctnetlink iteration, i.e. conntrack -L won't show them. 1074 */ 1075 hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 1076 1077 hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 1078 &nf_conntrack_hash[repl_idx]); 1079 1080 NF_CT_STAT_INC(net, clash_resolve); 1081 return NF_ACCEPT; 1082 } 1083 1084 /** 1085 * nf_ct_resolve_clash - attempt to handle clash without packet drop 1086 * 1087 * @skb: skb that causes the clash 1088 * @h: tuplehash of the clashing entry already in table 1089 * @reply_hash: hash slot for reply direction 1090 * 1091 * A conntrack entry can be inserted to the connection tracking table 1092 * if there is no existing entry with an identical tuple. 1093 * 1094 * If there is one, @skb (and the assocated, unconfirmed conntrack) has 1095 * to be dropped. In case @skb is retransmitted, next conntrack lookup 1096 * will find the already-existing entry. 1097 * 1098 * The major problem with such packet drop is the extra delay added by 1099 * the packet loss -- it will take some time for a retransmit to occur 1100 * (or the sender to time out when waiting for a reply). 1101 * 1102 * This function attempts to handle the situation without packet drop. 1103 * 1104 * If @skb has no NAT transformation or if the colliding entries are 1105 * exactly the same, only the to-be-confirmed conntrack entry is discarded 1106 * and @skb is associated with the conntrack entry already in the table. 1107 * 1108 * Failing that, the new, unconfirmed conntrack is still added to the table 1109 * provided that the collision only occurs in the ORIGINAL direction. 1110 * The new entry will be added only in the non-clashing REPLY direction, 1111 * so packets in the ORIGINAL direction will continue to match the existing 1112 * entry. The new entry will also have a fixed timeout so it expires -- 1113 * due to the collision, it will only see reply traffic. 1114 * 1115 * Returns NF_DROP if the clash could not be resolved. 1116 */ 1117 static __cold noinline int 1118 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h, 1119 u32 reply_hash) 1120 { 1121 /* This is the conntrack entry already in hashes that won race. */ 1122 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); 1123 const struct nf_conntrack_l4proto *l4proto; 1124 enum ip_conntrack_info ctinfo; 1125 struct nf_conn *loser_ct; 1126 struct net *net; 1127 int ret; 1128 1129 loser_ct = nf_ct_get(skb, &ctinfo); 1130 net = nf_ct_net(loser_ct); 1131 1132 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct)); 1133 if (!l4proto->allow_clash) 1134 goto drop; 1135 1136 ret = __nf_ct_resolve_clash(skb, h); 1137 if (ret == NF_ACCEPT) 1138 return ret; 1139 1140 ret = nf_ct_resolve_clash_harder(skb, reply_hash); 1141 if (ret == NF_ACCEPT) 1142 return ret; 1143 1144 drop: 1145 NF_CT_STAT_INC(net, drop); 1146 NF_CT_STAT_INC(net, insert_failed); 1147 return NF_DROP; 1148 } 1149 1150 /* Confirm a connection given skb; places it in hash table */ 1151 int 1152 __nf_conntrack_confirm(struct sk_buff *skb) 1153 { 1154 unsigned int chainlen = 0, sequence, max_chainlen; 1155 const struct nf_conntrack_zone *zone; 1156 unsigned int hash, reply_hash; 1157 struct nf_conntrack_tuple_hash *h; 1158 struct nf_conn *ct; 1159 struct nf_conn_help *help; 1160 struct hlist_nulls_node *n; 1161 enum ip_conntrack_info ctinfo; 1162 struct net *net; 1163 int ret = NF_DROP; 1164 1165 ct = nf_ct_get(skb, &ctinfo); 1166 net = nf_ct_net(ct); 1167 1168 /* ipt_REJECT uses nf_conntrack_attach to attach related 1169 ICMP/TCP RST packets in other direction. Actual packet 1170 which created connection will be IP_CT_NEW or for an 1171 expected connection, IP_CT_RELATED. */ 1172 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 1173 return NF_ACCEPT; 1174 1175 zone = nf_ct_zone(ct); 1176 local_bh_disable(); 1177 1178 do { 1179 sequence = read_seqcount_begin(&nf_conntrack_generation); 1180 /* reuse the hash saved before */ 1181 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 1182 hash = scale_hash(hash); 1183 reply_hash = hash_conntrack(net, 1184 &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 1185 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); 1186 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); 1187 1188 /* We're not in hash table, and we refuse to set up related 1189 * connections for unconfirmed conns. But packet copies and 1190 * REJECT will give spurious warnings here. 1191 */ 1192 1193 /* Another skb with the same unconfirmed conntrack may 1194 * win the race. This may happen for bridge(br_flood) 1195 * or broadcast/multicast packets do skb_clone with 1196 * unconfirmed conntrack. 1197 */ 1198 if (unlikely(nf_ct_is_confirmed(ct))) { 1199 WARN_ON_ONCE(1); 1200 nf_conntrack_double_unlock(hash, reply_hash); 1201 local_bh_enable(); 1202 return NF_DROP; 1203 } 1204 1205 if (!nf_ct_ext_valid_pre(ct->ext)) { 1206 NF_CT_STAT_INC(net, insert_failed); 1207 goto dying; 1208 } 1209 1210 pr_debug("Confirming conntrack %p\n", ct); 1211 /* We have to check the DYING flag after unlink to prevent 1212 * a race against nf_ct_get_next_corpse() possibly called from 1213 * user context, else we insert an already 'dead' hash, blocking 1214 * further use of that particular connection -JM. 1215 */ 1216 ct->status |= IPS_CONFIRMED; 1217 1218 if (unlikely(nf_ct_is_dying(ct))) { 1219 NF_CT_STAT_INC(net, insert_failed); 1220 goto dying; 1221 } 1222 1223 max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN); 1224 /* See if there's one in the list already, including reverse: 1225 NAT could have grabbed it without realizing, since we're 1226 not in the hash. If there is, we lost race. */ 1227 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) { 1228 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 1229 zone, net)) 1230 goto out; 1231 if (chainlen++ > max_chainlen) 1232 goto chaintoolong; 1233 } 1234 1235 chainlen = 0; 1236 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) { 1237 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 1238 zone, net)) 1239 goto out; 1240 if (chainlen++ > max_chainlen) { 1241 chaintoolong: 1242 NF_CT_STAT_INC(net, chaintoolong); 1243 NF_CT_STAT_INC(net, insert_failed); 1244 ret = NF_DROP; 1245 goto dying; 1246 } 1247 } 1248 1249 /* Timer relative to confirmation time, not original 1250 setting time, otherwise we'd get timer wrap in 1251 weird delay cases. */ 1252 ct->timeout += nfct_time_stamp; 1253 1254 __nf_conntrack_insert_prepare(ct); 1255 1256 /* Since the lookup is lockless, hash insertion must be done after 1257 * starting the timer and setting the CONFIRMED bit. The RCU barriers 1258 * guarantee that no other CPU can find the conntrack before the above 1259 * stores are visible. 1260 */ 1261 __nf_conntrack_hash_insert(ct, hash, reply_hash); 1262 nf_conntrack_double_unlock(hash, reply_hash); 1263 local_bh_enable(); 1264 1265 /* ext area is still valid (rcu read lock is held, 1266 * but will go out of scope soon, we need to remove 1267 * this conntrack again. 1268 */ 1269 if (!nf_ct_ext_valid_post(ct->ext)) { 1270 nf_ct_kill(ct); 1271 NF_CT_STAT_INC(net, drop); 1272 return NF_DROP; 1273 } 1274 1275 help = nfct_help(ct); 1276 if (help && help->helper) 1277 nf_conntrack_event_cache(IPCT_HELPER, ct); 1278 1279 nf_conntrack_event_cache(master_ct(ct) ? 1280 IPCT_RELATED : IPCT_NEW, ct); 1281 return NF_ACCEPT; 1282 1283 out: 1284 ret = nf_ct_resolve_clash(skb, h, reply_hash); 1285 dying: 1286 nf_conntrack_double_unlock(hash, reply_hash); 1287 local_bh_enable(); 1288 return ret; 1289 } 1290 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 1291 1292 /* Returns true if a connection correspondings to the tuple (required 1293 for NAT). */ 1294 int 1295 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 1296 const struct nf_conn *ignored_conntrack) 1297 { 1298 struct net *net = nf_ct_net(ignored_conntrack); 1299 const struct nf_conntrack_zone *zone; 1300 struct nf_conntrack_tuple_hash *h; 1301 struct hlist_nulls_head *ct_hash; 1302 unsigned int hash, hsize; 1303 struct hlist_nulls_node *n; 1304 struct nf_conn *ct; 1305 1306 zone = nf_ct_zone(ignored_conntrack); 1307 1308 rcu_read_lock(); 1309 begin: 1310 nf_conntrack_get_ht(&ct_hash, &hsize); 1311 hash = __hash_conntrack(net, tuple, nf_ct_zone_id(zone, IP_CT_DIR_REPLY), hsize); 1312 1313 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) { 1314 ct = nf_ct_tuplehash_to_ctrack(h); 1315 1316 if (ct == ignored_conntrack) 1317 continue; 1318 1319 if (nf_ct_is_expired(ct)) { 1320 nf_ct_gc_expired(ct); 1321 continue; 1322 } 1323 1324 if (nf_ct_key_equal(h, tuple, zone, net)) { 1325 /* Tuple is taken already, so caller will need to find 1326 * a new source port to use. 1327 * 1328 * Only exception: 1329 * If the *original tuples* are identical, then both 1330 * conntracks refer to the same flow. 1331 * This is a rare situation, it can occur e.g. when 1332 * more than one UDP packet is sent from same socket 1333 * in different threads. 1334 * 1335 * Let nf_ct_resolve_clash() deal with this later. 1336 */ 1337 if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 1338 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) && 1339 nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) 1340 continue; 1341 1342 NF_CT_STAT_INC_ATOMIC(net, found); 1343 rcu_read_unlock(); 1344 return 1; 1345 } 1346 } 1347 1348 if (get_nulls_value(n) != hash) { 1349 NF_CT_STAT_INC_ATOMIC(net, search_restart); 1350 goto begin; 1351 } 1352 1353 rcu_read_unlock(); 1354 1355 return 0; 1356 } 1357 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 1358 1359 #define NF_CT_EVICTION_RANGE 8 1360 1361 /* There's a small race here where we may free a just-assured 1362 connection. Too bad: we're in trouble anyway. */ 1363 static unsigned int early_drop_list(struct net *net, 1364 struct hlist_nulls_head *head) 1365 { 1366 struct nf_conntrack_tuple_hash *h; 1367 struct hlist_nulls_node *n; 1368 unsigned int drops = 0; 1369 struct nf_conn *tmp; 1370 1371 hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) { 1372 tmp = nf_ct_tuplehash_to_ctrack(h); 1373 1374 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) 1375 continue; 1376 1377 if (nf_ct_is_expired(tmp)) { 1378 nf_ct_gc_expired(tmp); 1379 continue; 1380 } 1381 1382 if (test_bit(IPS_ASSURED_BIT, &tmp->status) || 1383 !net_eq(nf_ct_net(tmp), net) || 1384 nf_ct_is_dying(tmp)) 1385 continue; 1386 1387 if (!refcount_inc_not_zero(&tmp->ct_general.use)) 1388 continue; 1389 1390 /* kill only if still in same netns -- might have moved due to 1391 * SLAB_TYPESAFE_BY_RCU rules. 1392 * 1393 * We steal the timer reference. If that fails timer has 1394 * already fired or someone else deleted it. Just drop ref 1395 * and move to next entry. 1396 */ 1397 if (net_eq(nf_ct_net(tmp), net) && 1398 nf_ct_is_confirmed(tmp) && 1399 nf_ct_delete(tmp, 0, 0)) 1400 drops++; 1401 1402 nf_ct_put(tmp); 1403 } 1404 1405 return drops; 1406 } 1407 1408 static noinline int early_drop(struct net *net, unsigned int hash) 1409 { 1410 unsigned int i, bucket; 1411 1412 for (i = 0; i < NF_CT_EVICTION_RANGE; i++) { 1413 struct hlist_nulls_head *ct_hash; 1414 unsigned int hsize, drops; 1415 1416 rcu_read_lock(); 1417 nf_conntrack_get_ht(&ct_hash, &hsize); 1418 if (!i) 1419 bucket = reciprocal_scale(hash, hsize); 1420 else 1421 bucket = (bucket + 1) % hsize; 1422 1423 drops = early_drop_list(net, &ct_hash[bucket]); 1424 rcu_read_unlock(); 1425 1426 if (drops) { 1427 NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops); 1428 return true; 1429 } 1430 } 1431 1432 return false; 1433 } 1434 1435 static bool gc_worker_skip_ct(const struct nf_conn *ct) 1436 { 1437 return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct); 1438 } 1439 1440 static bool gc_worker_can_early_drop(const struct nf_conn *ct) 1441 { 1442 const struct nf_conntrack_l4proto *l4proto; 1443 1444 if (!test_bit(IPS_ASSURED_BIT, &ct->status)) 1445 return true; 1446 1447 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct)); 1448 if (l4proto->can_early_drop && l4proto->can_early_drop(ct)) 1449 return true; 1450 1451 return false; 1452 } 1453 1454 static void gc_worker(struct work_struct *work) 1455 { 1456 unsigned int i, hashsz, nf_conntrack_max95 = 0; 1457 u32 end_time, start_time = nfct_time_stamp; 1458 struct conntrack_gc_work *gc_work; 1459 unsigned int expired_count = 0; 1460 unsigned long next_run; 1461 s32 delta_time; 1462 1463 gc_work = container_of(work, struct conntrack_gc_work, dwork.work); 1464 1465 i = gc_work->next_bucket; 1466 if (gc_work->early_drop) 1467 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u; 1468 1469 if (i == 0) { 1470 gc_work->avg_timeout = GC_SCAN_INTERVAL_INIT; 1471 gc_work->start_time = start_time; 1472 } 1473 1474 next_run = gc_work->avg_timeout; 1475 1476 end_time = start_time + GC_SCAN_MAX_DURATION; 1477 1478 do { 1479 struct nf_conntrack_tuple_hash *h; 1480 struct hlist_nulls_head *ct_hash; 1481 struct hlist_nulls_node *n; 1482 struct nf_conn *tmp; 1483 1484 rcu_read_lock(); 1485 1486 nf_conntrack_get_ht(&ct_hash, &hashsz); 1487 if (i >= hashsz) { 1488 rcu_read_unlock(); 1489 break; 1490 } 1491 1492 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) { 1493 struct nf_conntrack_net *cnet; 1494 unsigned long expires; 1495 struct net *net; 1496 1497 tmp = nf_ct_tuplehash_to_ctrack(h); 1498 1499 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) { 1500 nf_ct_offload_timeout(tmp); 1501 continue; 1502 } 1503 1504 if (expired_count > GC_SCAN_EXPIRED_MAX) { 1505 rcu_read_unlock(); 1506 1507 gc_work->next_bucket = i; 1508 gc_work->avg_timeout = next_run; 1509 1510 delta_time = nfct_time_stamp - gc_work->start_time; 1511 1512 /* re-sched immediately if total cycle time is exceeded */ 1513 next_run = delta_time < (s32)GC_SCAN_INTERVAL_MAX; 1514 goto early_exit; 1515 } 1516 1517 if (nf_ct_is_expired(tmp)) { 1518 nf_ct_gc_expired(tmp); 1519 expired_count++; 1520 continue; 1521 } 1522 1523 expires = clamp(nf_ct_expires(tmp), GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_CLAMP); 1524 next_run += expires; 1525 next_run /= 2u; 1526 1527 if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp)) 1528 continue; 1529 1530 net = nf_ct_net(tmp); 1531 cnet = nf_ct_pernet(net); 1532 if (atomic_read(&cnet->count) < nf_conntrack_max95) 1533 continue; 1534 1535 /* need to take reference to avoid possible races */ 1536 if (!refcount_inc_not_zero(&tmp->ct_general.use)) 1537 continue; 1538 1539 if (gc_worker_skip_ct(tmp)) { 1540 nf_ct_put(tmp); 1541 continue; 1542 } 1543 1544 if (gc_worker_can_early_drop(tmp)) { 1545 nf_ct_kill(tmp); 1546 expired_count++; 1547 } 1548 1549 nf_ct_put(tmp); 1550 } 1551 1552 /* could check get_nulls_value() here and restart if ct 1553 * was moved to another chain. But given gc is best-effort 1554 * we will just continue with next hash slot. 1555 */ 1556 rcu_read_unlock(); 1557 cond_resched(); 1558 i++; 1559 1560 delta_time = nfct_time_stamp - end_time; 1561 if (delta_time > 0 && i < hashsz) { 1562 gc_work->avg_timeout = next_run; 1563 gc_work->next_bucket = i; 1564 next_run = 0; 1565 goto early_exit; 1566 } 1567 } while (i < hashsz); 1568 1569 gc_work->next_bucket = 0; 1570 1571 next_run = clamp(next_run, GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_MAX); 1572 1573 delta_time = max_t(s32, nfct_time_stamp - gc_work->start_time, 1); 1574 if (next_run > (unsigned long)delta_time) 1575 next_run -= delta_time; 1576 else 1577 next_run = 1; 1578 1579 early_exit: 1580 if (gc_work->exiting) 1581 return; 1582 1583 if (next_run) 1584 gc_work->early_drop = false; 1585 1586 queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run); 1587 } 1588 1589 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work) 1590 { 1591 INIT_DELAYED_WORK(&gc_work->dwork, gc_worker); 1592 gc_work->exiting = false; 1593 } 1594 1595 static struct nf_conn * 1596 __nf_conntrack_alloc(struct net *net, 1597 const struct nf_conntrack_zone *zone, 1598 const struct nf_conntrack_tuple *orig, 1599 const struct nf_conntrack_tuple *repl, 1600 gfp_t gfp, u32 hash) 1601 { 1602 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 1603 unsigned int ct_count; 1604 struct nf_conn *ct; 1605 1606 /* We don't want any race condition at early drop stage */ 1607 ct_count = atomic_inc_return(&cnet->count); 1608 1609 if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) { 1610 if (!early_drop(net, hash)) { 1611 if (!conntrack_gc_work.early_drop) 1612 conntrack_gc_work.early_drop = true; 1613 atomic_dec(&cnet->count); 1614 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n"); 1615 return ERR_PTR(-ENOMEM); 1616 } 1617 } 1618 1619 /* 1620 * Do not use kmem_cache_zalloc(), as this cache uses 1621 * SLAB_TYPESAFE_BY_RCU. 1622 */ 1623 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp); 1624 if (ct == NULL) 1625 goto out; 1626 1627 spin_lock_init(&ct->lock); 1628 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 1629 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 1630 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 1631 /* save hash for reusing when confirming */ 1632 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 1633 ct->status = 0; 1634 WRITE_ONCE(ct->timeout, 0); 1635 write_pnet(&ct->ct_net, net); 1636 memset_after(ct, 0, __nfct_init_offset); 1637 1638 nf_ct_zone_add(ct, zone); 1639 1640 /* Because we use RCU lookups, we set ct_general.use to zero before 1641 * this is inserted in any list. 1642 */ 1643 refcount_set(&ct->ct_general.use, 0); 1644 return ct; 1645 out: 1646 atomic_dec(&cnet->count); 1647 return ERR_PTR(-ENOMEM); 1648 } 1649 1650 struct nf_conn *nf_conntrack_alloc(struct net *net, 1651 const struct nf_conntrack_zone *zone, 1652 const struct nf_conntrack_tuple *orig, 1653 const struct nf_conntrack_tuple *repl, 1654 gfp_t gfp) 1655 { 1656 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 1657 } 1658 EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 1659 1660 void nf_conntrack_free(struct nf_conn *ct) 1661 { 1662 struct net *net = nf_ct_net(ct); 1663 struct nf_conntrack_net *cnet; 1664 1665 /* A freed object has refcnt == 0, that's 1666 * the golden rule for SLAB_TYPESAFE_BY_RCU 1667 */ 1668 WARN_ON(refcount_read(&ct->ct_general.use) != 0); 1669 1670 if (ct->status & IPS_SRC_NAT_DONE) { 1671 const struct nf_nat_hook *nat_hook; 1672 1673 rcu_read_lock(); 1674 nat_hook = rcu_dereference(nf_nat_hook); 1675 if (nat_hook) 1676 nat_hook->remove_nat_bysrc(ct); 1677 rcu_read_unlock(); 1678 } 1679 1680 kfree(ct->ext); 1681 kmem_cache_free(nf_conntrack_cachep, ct); 1682 cnet = nf_ct_pernet(net); 1683 1684 smp_mb__before_atomic(); 1685 atomic_dec(&cnet->count); 1686 } 1687 EXPORT_SYMBOL_GPL(nf_conntrack_free); 1688 1689 1690 /* Allocate a new conntrack: we return -ENOMEM if classification 1691 failed due to stress. Otherwise it really is unclassifiable. */ 1692 static noinline struct nf_conntrack_tuple_hash * 1693 init_conntrack(struct net *net, struct nf_conn *tmpl, 1694 const struct nf_conntrack_tuple *tuple, 1695 struct sk_buff *skb, 1696 unsigned int dataoff, u32 hash) 1697 { 1698 struct nf_conn *ct; 1699 struct nf_conn_help *help; 1700 struct nf_conntrack_tuple repl_tuple; 1701 #ifdef CONFIG_NF_CONNTRACK_EVENTS 1702 struct nf_conntrack_ecache *ecache; 1703 #endif 1704 struct nf_conntrack_expect *exp = NULL; 1705 const struct nf_conntrack_zone *zone; 1706 struct nf_conn_timeout *timeout_ext; 1707 struct nf_conntrack_zone tmp; 1708 struct nf_conntrack_net *cnet; 1709 1710 if (!nf_ct_invert_tuple(&repl_tuple, tuple)) { 1711 pr_debug("Can't invert tuple.\n"); 1712 return NULL; 1713 } 1714 1715 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); 1716 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 1717 hash); 1718 if (IS_ERR(ct)) 1719 return (struct nf_conntrack_tuple_hash *)ct; 1720 1721 if (!nf_ct_add_synproxy(ct, tmpl)) { 1722 nf_conntrack_free(ct); 1723 return ERR_PTR(-ENOMEM); 1724 } 1725 1726 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; 1727 1728 if (timeout_ext) 1729 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout), 1730 GFP_ATOMIC); 1731 1732 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 1733 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 1734 nf_ct_labels_ext_add(ct); 1735 1736 #ifdef CONFIG_NF_CONNTRACK_EVENTS 1737 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 1738 1739 if ((ecache || net->ct.sysctl_events) && 1740 !nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 1741 ecache ? ecache->expmask : 0, 1742 GFP_ATOMIC)) { 1743 nf_conntrack_free(ct); 1744 return ERR_PTR(-ENOMEM); 1745 } 1746 #endif 1747 1748 cnet = nf_ct_pernet(net); 1749 if (cnet->expect_count) { 1750 spin_lock_bh(&nf_conntrack_expect_lock); 1751 exp = nf_ct_find_expectation(net, zone, tuple); 1752 if (exp) { 1753 pr_debug("expectation arrives ct=%p exp=%p\n", 1754 ct, exp); 1755 /* Welcome, Mr. Bond. We've been expecting you... */ 1756 __set_bit(IPS_EXPECTED_BIT, &ct->status); 1757 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */ 1758 ct->master = exp->master; 1759 if (exp->helper) { 1760 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 1761 if (help) 1762 rcu_assign_pointer(help->helper, exp->helper); 1763 } 1764 1765 #ifdef CONFIG_NF_CONNTRACK_MARK 1766 ct->mark = exp->master->mark; 1767 #endif 1768 #ifdef CONFIG_NF_CONNTRACK_SECMARK 1769 ct->secmark = exp->master->secmark; 1770 #endif 1771 NF_CT_STAT_INC(net, expect_new); 1772 } 1773 spin_unlock_bh(&nf_conntrack_expect_lock); 1774 } 1775 if (!exp) 1776 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 1777 1778 /* Now it is going to be associated with an sk_buff, set refcount to 1. */ 1779 refcount_set(&ct->ct_general.use, 1); 1780 1781 if (exp) { 1782 if (exp->expectfn) 1783 exp->expectfn(ct, exp); 1784 nf_ct_expect_put(exp); 1785 } 1786 1787 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 1788 } 1789 1790 /* On success, returns 0, sets skb->_nfct | ctinfo */ 1791 static int 1792 resolve_normal_ct(struct nf_conn *tmpl, 1793 struct sk_buff *skb, 1794 unsigned int dataoff, 1795 u_int8_t protonum, 1796 const struct nf_hook_state *state) 1797 { 1798 const struct nf_conntrack_zone *zone; 1799 struct nf_conntrack_tuple tuple; 1800 struct nf_conntrack_tuple_hash *h; 1801 enum ip_conntrack_info ctinfo; 1802 struct nf_conntrack_zone tmp; 1803 u32 hash, zone_id, rid; 1804 struct nf_conn *ct; 1805 1806 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 1807 dataoff, state->pf, protonum, state->net, 1808 &tuple)) { 1809 pr_debug("Can't get tuple\n"); 1810 return 0; 1811 } 1812 1813 /* look for tuple match */ 1814 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); 1815 1816 zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL); 1817 hash = hash_conntrack_raw(&tuple, zone_id, state->net); 1818 h = __nf_conntrack_find_get(state->net, zone, &tuple, hash); 1819 1820 if (!h) { 1821 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY); 1822 if (zone_id != rid) { 1823 u32 tmp = hash_conntrack_raw(&tuple, rid, state->net); 1824 1825 h = __nf_conntrack_find_get(state->net, zone, &tuple, tmp); 1826 } 1827 } 1828 1829 if (!h) { 1830 h = init_conntrack(state->net, tmpl, &tuple, 1831 skb, dataoff, hash); 1832 if (!h) 1833 return 0; 1834 if (IS_ERR(h)) 1835 return PTR_ERR(h); 1836 } 1837 ct = nf_ct_tuplehash_to_ctrack(h); 1838 1839 /* It exists; we have (non-exclusive) reference. */ 1840 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 1841 ctinfo = IP_CT_ESTABLISHED_REPLY; 1842 } else { 1843 /* Once we've had two way comms, always ESTABLISHED. */ 1844 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 1845 pr_debug("normal packet for %p\n", ct); 1846 ctinfo = IP_CT_ESTABLISHED; 1847 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 1848 pr_debug("related packet for %p\n", ct); 1849 ctinfo = IP_CT_RELATED; 1850 } else { 1851 pr_debug("new packet for %p\n", ct); 1852 ctinfo = IP_CT_NEW; 1853 } 1854 } 1855 nf_ct_set(skb, ct, ctinfo); 1856 return 0; 1857 } 1858 1859 /* 1860 * icmp packets need special treatment to handle error messages that are 1861 * related to a connection. 1862 * 1863 * Callers need to check if skb has a conntrack assigned when this 1864 * helper returns; in such case skb belongs to an already known connection. 1865 */ 1866 static unsigned int __cold 1867 nf_conntrack_handle_icmp(struct nf_conn *tmpl, 1868 struct sk_buff *skb, 1869 unsigned int dataoff, 1870 u8 protonum, 1871 const struct nf_hook_state *state) 1872 { 1873 int ret; 1874 1875 if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP) 1876 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state); 1877 #if IS_ENABLED(CONFIG_IPV6) 1878 else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6) 1879 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state); 1880 #endif 1881 else 1882 return NF_ACCEPT; 1883 1884 if (ret <= 0) 1885 NF_CT_STAT_INC_ATOMIC(state->net, error); 1886 1887 return ret; 1888 } 1889 1890 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb, 1891 enum ip_conntrack_info ctinfo) 1892 { 1893 const unsigned int *timeout = nf_ct_timeout_lookup(ct); 1894 1895 if (!timeout) 1896 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout; 1897 1898 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout); 1899 return NF_ACCEPT; 1900 } 1901 1902 /* Returns verdict for packet, or -1 for invalid. */ 1903 static int nf_conntrack_handle_packet(struct nf_conn *ct, 1904 struct sk_buff *skb, 1905 unsigned int dataoff, 1906 enum ip_conntrack_info ctinfo, 1907 const struct nf_hook_state *state) 1908 { 1909 switch (nf_ct_protonum(ct)) { 1910 case IPPROTO_TCP: 1911 return nf_conntrack_tcp_packet(ct, skb, dataoff, 1912 ctinfo, state); 1913 case IPPROTO_UDP: 1914 return nf_conntrack_udp_packet(ct, skb, dataoff, 1915 ctinfo, state); 1916 case IPPROTO_ICMP: 1917 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state); 1918 #if IS_ENABLED(CONFIG_IPV6) 1919 case IPPROTO_ICMPV6: 1920 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state); 1921 #endif 1922 #ifdef CONFIG_NF_CT_PROTO_UDPLITE 1923 case IPPROTO_UDPLITE: 1924 return nf_conntrack_udplite_packet(ct, skb, dataoff, 1925 ctinfo, state); 1926 #endif 1927 #ifdef CONFIG_NF_CT_PROTO_SCTP 1928 case IPPROTO_SCTP: 1929 return nf_conntrack_sctp_packet(ct, skb, dataoff, 1930 ctinfo, state); 1931 #endif 1932 #ifdef CONFIG_NF_CT_PROTO_DCCP 1933 case IPPROTO_DCCP: 1934 return nf_conntrack_dccp_packet(ct, skb, dataoff, 1935 ctinfo, state); 1936 #endif 1937 #ifdef CONFIG_NF_CT_PROTO_GRE 1938 case IPPROTO_GRE: 1939 return nf_conntrack_gre_packet(ct, skb, dataoff, 1940 ctinfo, state); 1941 #endif 1942 } 1943 1944 return generic_packet(ct, skb, ctinfo); 1945 } 1946 1947 unsigned int 1948 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state) 1949 { 1950 enum ip_conntrack_info ctinfo; 1951 struct nf_conn *ct, *tmpl; 1952 u_int8_t protonum; 1953 int dataoff, ret; 1954 1955 tmpl = nf_ct_get(skb, &ctinfo); 1956 if (tmpl || ctinfo == IP_CT_UNTRACKED) { 1957 /* Previously seen (loopback or untracked)? Ignore. */ 1958 if ((tmpl && !nf_ct_is_template(tmpl)) || 1959 ctinfo == IP_CT_UNTRACKED) 1960 return NF_ACCEPT; 1961 skb->_nfct = 0; 1962 } 1963 1964 /* rcu_read_lock()ed by nf_hook_thresh */ 1965 dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum); 1966 if (dataoff <= 0) { 1967 pr_debug("not prepared to track yet or error occurred\n"); 1968 NF_CT_STAT_INC_ATOMIC(state->net, invalid); 1969 ret = NF_ACCEPT; 1970 goto out; 1971 } 1972 1973 if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) { 1974 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff, 1975 protonum, state); 1976 if (ret <= 0) { 1977 ret = -ret; 1978 goto out; 1979 } 1980 /* ICMP[v6] protocol trackers may assign one conntrack. */ 1981 if (skb->_nfct) 1982 goto out; 1983 } 1984 repeat: 1985 ret = resolve_normal_ct(tmpl, skb, dataoff, 1986 protonum, state); 1987 if (ret < 0) { 1988 /* Too stressed to deal. */ 1989 NF_CT_STAT_INC_ATOMIC(state->net, drop); 1990 ret = NF_DROP; 1991 goto out; 1992 } 1993 1994 ct = nf_ct_get(skb, &ctinfo); 1995 if (!ct) { 1996 /* Not valid part of a connection */ 1997 NF_CT_STAT_INC_ATOMIC(state->net, invalid); 1998 ret = NF_ACCEPT; 1999 goto out; 2000 } 2001 2002 ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state); 2003 if (ret <= 0) { 2004 /* Invalid: inverse of the return code tells 2005 * the netfilter core what to do */ 2006 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 2007 nf_ct_put(ct); 2008 skb->_nfct = 0; 2009 /* Special case: TCP tracker reports an attempt to reopen a 2010 * closed/aborted connection. We have to go back and create a 2011 * fresh conntrack. 2012 */ 2013 if (ret == -NF_REPEAT) 2014 goto repeat; 2015 2016 NF_CT_STAT_INC_ATOMIC(state->net, invalid); 2017 if (ret == -NF_DROP) 2018 NF_CT_STAT_INC_ATOMIC(state->net, drop); 2019 2020 ret = -ret; 2021 goto out; 2022 } 2023 2024 if (ctinfo == IP_CT_ESTABLISHED_REPLY && 2025 !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 2026 nf_conntrack_event_cache(IPCT_REPLY, ct); 2027 out: 2028 if (tmpl) 2029 nf_ct_put(tmpl); 2030 2031 return ret; 2032 } 2033 EXPORT_SYMBOL_GPL(nf_conntrack_in); 2034 2035 /* Alter reply tuple (maybe alter helper). This is for NAT, and is 2036 implicitly racy: see __nf_conntrack_confirm */ 2037 void nf_conntrack_alter_reply(struct nf_conn *ct, 2038 const struct nf_conntrack_tuple *newreply) 2039 { 2040 struct nf_conn_help *help = nfct_help(ct); 2041 2042 /* Should be unconfirmed, so not in hash table yet */ 2043 WARN_ON(nf_ct_is_confirmed(ct)); 2044 2045 pr_debug("Altering reply tuple of %p to ", ct); 2046 nf_ct_dump_tuple(newreply); 2047 2048 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 2049 if (ct->master || (help && !hlist_empty(&help->expectations))) 2050 return; 2051 2052 rcu_read_lock(); 2053 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 2054 rcu_read_unlock(); 2055 } 2056 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 2057 2058 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 2059 void __nf_ct_refresh_acct(struct nf_conn *ct, 2060 enum ip_conntrack_info ctinfo, 2061 const struct sk_buff *skb, 2062 u32 extra_jiffies, 2063 bool do_acct) 2064 { 2065 /* Only update if this is not a fixed timeout */ 2066 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 2067 goto acct; 2068 2069 /* If not in hash table, timer will not be active yet */ 2070 if (nf_ct_is_confirmed(ct)) 2071 extra_jiffies += nfct_time_stamp; 2072 2073 if (READ_ONCE(ct->timeout) != extra_jiffies) 2074 WRITE_ONCE(ct->timeout, extra_jiffies); 2075 acct: 2076 if (do_acct) 2077 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len); 2078 } 2079 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 2080 2081 bool nf_ct_kill_acct(struct nf_conn *ct, 2082 enum ip_conntrack_info ctinfo, 2083 const struct sk_buff *skb) 2084 { 2085 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len); 2086 2087 return nf_ct_delete(ct, 0, 0); 2088 } 2089 EXPORT_SYMBOL_GPL(nf_ct_kill_acct); 2090 2091 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 2092 2093 #include <linux/netfilter/nfnetlink.h> 2094 #include <linux/netfilter/nfnetlink_conntrack.h> 2095 #include <linux/mutex.h> 2096 2097 /* Generic function for tcp/udp/sctp/dccp and alike. */ 2098 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 2099 const struct nf_conntrack_tuple *tuple) 2100 { 2101 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) || 2102 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port)) 2103 goto nla_put_failure; 2104 return 0; 2105 2106 nla_put_failure: 2107 return -1; 2108 } 2109 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 2110 2111 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 2112 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 2113 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 2114 }; 2115 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 2116 2117 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 2118 struct nf_conntrack_tuple *t, 2119 u_int32_t flags) 2120 { 2121 if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) { 2122 if (!tb[CTA_PROTO_SRC_PORT]) 2123 return -EINVAL; 2124 2125 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 2126 } 2127 2128 if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) { 2129 if (!tb[CTA_PROTO_DST_PORT]) 2130 return -EINVAL; 2131 2132 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 2133 } 2134 2135 return 0; 2136 } 2137 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 2138 2139 unsigned int nf_ct_port_nlattr_tuple_size(void) 2140 { 2141 static unsigned int size __read_mostly; 2142 2143 if (!size) 2144 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 2145 2146 return size; 2147 } 2148 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 2149 #endif 2150 2151 /* Used by ipt_REJECT and ip6t_REJECT. */ 2152 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb) 2153 { 2154 struct nf_conn *ct; 2155 enum ip_conntrack_info ctinfo; 2156 2157 /* This ICMP is in reverse direction to the packet which caused it */ 2158 ct = nf_ct_get(skb, &ctinfo); 2159 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 2160 ctinfo = IP_CT_RELATED_REPLY; 2161 else 2162 ctinfo = IP_CT_RELATED; 2163 2164 /* Attach to new skbuff, and increment count */ 2165 nf_ct_set(nskb, ct, ctinfo); 2166 nf_conntrack_get(skb_nfct(nskb)); 2167 } 2168 2169 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb, 2170 struct nf_conn *ct, 2171 enum ip_conntrack_info ctinfo) 2172 { 2173 const struct nf_nat_hook *nat_hook; 2174 struct nf_conntrack_tuple_hash *h; 2175 struct nf_conntrack_tuple tuple; 2176 unsigned int status; 2177 int dataoff; 2178 u16 l3num; 2179 u8 l4num; 2180 2181 l3num = nf_ct_l3num(ct); 2182 2183 dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num); 2184 if (dataoff <= 0) 2185 return -1; 2186 2187 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num, 2188 l4num, net, &tuple)) 2189 return -1; 2190 2191 if (ct->status & IPS_SRC_NAT) { 2192 memcpy(tuple.src.u3.all, 2193 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all, 2194 sizeof(tuple.src.u3.all)); 2195 tuple.src.u.all = 2196 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all; 2197 } 2198 2199 if (ct->status & IPS_DST_NAT) { 2200 memcpy(tuple.dst.u3.all, 2201 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all, 2202 sizeof(tuple.dst.u3.all)); 2203 tuple.dst.u.all = 2204 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all; 2205 } 2206 2207 h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple); 2208 if (!h) 2209 return 0; 2210 2211 /* Store status bits of the conntrack that is clashing to re-do NAT 2212 * mangling according to what it has been done already to this packet. 2213 */ 2214 status = ct->status; 2215 2216 nf_ct_put(ct); 2217 ct = nf_ct_tuplehash_to_ctrack(h); 2218 nf_ct_set(skb, ct, ctinfo); 2219 2220 nat_hook = rcu_dereference(nf_nat_hook); 2221 if (!nat_hook) 2222 return 0; 2223 2224 if (status & IPS_SRC_NAT && 2225 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC, 2226 IP_CT_DIR_ORIGINAL) == NF_DROP) 2227 return -1; 2228 2229 if (status & IPS_DST_NAT && 2230 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST, 2231 IP_CT_DIR_ORIGINAL) == NF_DROP) 2232 return -1; 2233 2234 return 0; 2235 } 2236 2237 /* This packet is coming from userspace via nf_queue, complete the packet 2238 * processing after the helper invocation in nf_confirm(). 2239 */ 2240 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct, 2241 enum ip_conntrack_info ctinfo) 2242 { 2243 const struct nf_conntrack_helper *helper; 2244 const struct nf_conn_help *help; 2245 int protoff; 2246 2247 help = nfct_help(ct); 2248 if (!help) 2249 return 0; 2250 2251 helper = rcu_dereference(help->helper); 2252 if (!(helper->flags & NF_CT_HELPER_F_USERSPACE)) 2253 return 0; 2254 2255 switch (nf_ct_l3num(ct)) { 2256 case NFPROTO_IPV4: 2257 protoff = skb_network_offset(skb) + ip_hdrlen(skb); 2258 break; 2259 #if IS_ENABLED(CONFIG_IPV6) 2260 case NFPROTO_IPV6: { 2261 __be16 frag_off; 2262 u8 pnum; 2263 2264 pnum = ipv6_hdr(skb)->nexthdr; 2265 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum, 2266 &frag_off); 2267 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) 2268 return 0; 2269 break; 2270 } 2271 #endif 2272 default: 2273 return 0; 2274 } 2275 2276 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) && 2277 !nf_is_loopback_packet(skb)) { 2278 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) { 2279 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop); 2280 return -1; 2281 } 2282 } 2283 2284 /* We've seen it coming out the other side: confirm it */ 2285 return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0; 2286 } 2287 2288 static int nf_conntrack_update(struct net *net, struct sk_buff *skb) 2289 { 2290 enum ip_conntrack_info ctinfo; 2291 struct nf_conn *ct; 2292 int err; 2293 2294 ct = nf_ct_get(skb, &ctinfo); 2295 if (!ct) 2296 return 0; 2297 2298 if (!nf_ct_is_confirmed(ct)) { 2299 err = __nf_conntrack_update(net, skb, ct, ctinfo); 2300 if (err < 0) 2301 return err; 2302 2303 ct = nf_ct_get(skb, &ctinfo); 2304 } 2305 2306 return nf_confirm_cthelper(skb, ct, ctinfo); 2307 } 2308 2309 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 2310 const struct sk_buff *skb) 2311 { 2312 const struct nf_conntrack_tuple *src_tuple; 2313 const struct nf_conntrack_tuple_hash *hash; 2314 struct nf_conntrack_tuple srctuple; 2315 enum ip_conntrack_info ctinfo; 2316 struct nf_conn *ct; 2317 2318 ct = nf_ct_get(skb, &ctinfo); 2319 if (ct) { 2320 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo)); 2321 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple)); 2322 return true; 2323 } 2324 2325 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), 2326 NFPROTO_IPV4, dev_net(skb->dev), 2327 &srctuple)) 2328 return false; 2329 2330 hash = nf_conntrack_find_get(dev_net(skb->dev), 2331 &nf_ct_zone_dflt, 2332 &srctuple); 2333 if (!hash) 2334 return false; 2335 2336 ct = nf_ct_tuplehash_to_ctrack(hash); 2337 src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir); 2338 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple)); 2339 nf_ct_put(ct); 2340 2341 return true; 2342 } 2343 2344 /* Bring out ya dead! */ 2345 static struct nf_conn * 2346 get_next_corpse(int (*iter)(struct nf_conn *i, void *data), 2347 const struct nf_ct_iter_data *iter_data, unsigned int *bucket) 2348 { 2349 struct nf_conntrack_tuple_hash *h; 2350 struct nf_conn *ct; 2351 struct hlist_nulls_node *n; 2352 spinlock_t *lockp; 2353 2354 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) { 2355 struct hlist_nulls_head *hslot = &nf_conntrack_hash[*bucket]; 2356 2357 if (hlist_nulls_empty(hslot)) 2358 continue; 2359 2360 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS]; 2361 local_bh_disable(); 2362 nf_conntrack_lock(lockp); 2363 hlist_nulls_for_each_entry(h, n, hslot, hnnode) { 2364 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY) 2365 continue; 2366 /* All nf_conn objects are added to hash table twice, one 2367 * for original direction tuple, once for the reply tuple. 2368 * 2369 * Exception: In the IPS_NAT_CLASH case, only the reply 2370 * tuple is added (the original tuple already existed for 2371 * a different object). 2372 * 2373 * We only need to call the iterator once for each 2374 * conntrack, so we just use the 'reply' direction 2375 * tuple while iterating. 2376 */ 2377 ct = nf_ct_tuplehash_to_ctrack(h); 2378 2379 if (iter_data->net && 2380 !net_eq(iter_data->net, nf_ct_net(ct))) 2381 continue; 2382 2383 if (iter(ct, iter_data->data)) 2384 goto found; 2385 } 2386 spin_unlock(lockp); 2387 local_bh_enable(); 2388 cond_resched(); 2389 } 2390 2391 return NULL; 2392 found: 2393 refcount_inc(&ct->ct_general.use); 2394 spin_unlock(lockp); 2395 local_bh_enable(); 2396 return ct; 2397 } 2398 2399 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), 2400 const struct nf_ct_iter_data *iter_data) 2401 { 2402 unsigned int bucket = 0; 2403 struct nf_conn *ct; 2404 2405 might_sleep(); 2406 2407 mutex_lock(&nf_conntrack_mutex); 2408 while ((ct = get_next_corpse(iter, iter_data, &bucket)) != NULL) { 2409 /* Time to push up daises... */ 2410 2411 nf_ct_delete(ct, iter_data->portid, iter_data->report); 2412 nf_ct_put(ct); 2413 cond_resched(); 2414 } 2415 mutex_unlock(&nf_conntrack_mutex); 2416 } 2417 2418 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data), 2419 const struct nf_ct_iter_data *iter_data) 2420 { 2421 struct net *net = iter_data->net; 2422 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2423 2424 might_sleep(); 2425 2426 if (atomic_read(&cnet->count) == 0) 2427 return; 2428 2429 nf_ct_iterate_cleanup(iter, iter_data); 2430 } 2431 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net); 2432 2433 /** 2434 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table 2435 * @iter: callback to invoke for each conntrack 2436 * @data: data to pass to @iter 2437 * 2438 * Like nf_ct_iterate_cleanup, but first marks conntracks on the 2439 * unconfirmed list as dying (so they will not be inserted into 2440 * main table). 2441 * 2442 * Can only be called in module exit path. 2443 */ 2444 void 2445 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data) 2446 { 2447 struct nf_ct_iter_data iter_data = {}; 2448 struct net *net; 2449 2450 down_read(&net_rwsem); 2451 for_each_net(net) { 2452 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2453 2454 if (atomic_read(&cnet->count) == 0) 2455 continue; 2456 nf_queue_nf_hook_drop(net); 2457 } 2458 up_read(&net_rwsem); 2459 2460 /* Need to wait for netns cleanup worker to finish, if its 2461 * running -- it might have deleted a net namespace from 2462 * the global list, so hook drop above might not have 2463 * affected all namespaces. 2464 */ 2465 net_ns_barrier(); 2466 2467 /* a skb w. unconfirmed conntrack could have been reinjected just 2468 * before we called nf_queue_nf_hook_drop(). 2469 * 2470 * This makes sure its inserted into conntrack table. 2471 */ 2472 synchronize_net(); 2473 2474 nf_ct_ext_bump_genid(); 2475 iter_data.data = data; 2476 nf_ct_iterate_cleanup(iter, &iter_data); 2477 2478 /* Another cpu might be in a rcu read section with 2479 * rcu protected pointer cleared in iter callback 2480 * or hidden via nf_ct_ext_bump_genid() above. 2481 * 2482 * Wait until those are done. 2483 */ 2484 synchronize_rcu(); 2485 } 2486 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy); 2487 2488 static int kill_all(struct nf_conn *i, void *data) 2489 { 2490 return 1; 2491 } 2492 2493 void nf_conntrack_cleanup_start(void) 2494 { 2495 conntrack_gc_work.exiting = true; 2496 } 2497 2498 void nf_conntrack_cleanup_end(void) 2499 { 2500 RCU_INIT_POINTER(nf_ct_hook, NULL); 2501 cancel_delayed_work_sync(&conntrack_gc_work.dwork); 2502 kvfree(nf_conntrack_hash); 2503 2504 nf_conntrack_proto_fini(); 2505 nf_conntrack_helper_fini(); 2506 nf_conntrack_expect_fini(); 2507 2508 kmem_cache_destroy(nf_conntrack_cachep); 2509 } 2510 2511 /* 2512 * Mishearing the voices in his head, our hero wonders how he's 2513 * supposed to kill the mall. 2514 */ 2515 void nf_conntrack_cleanup_net(struct net *net) 2516 { 2517 LIST_HEAD(single); 2518 2519 list_add(&net->exit_list, &single); 2520 nf_conntrack_cleanup_net_list(&single); 2521 } 2522 2523 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list) 2524 { 2525 struct nf_ct_iter_data iter_data = {}; 2526 struct net *net; 2527 int busy; 2528 2529 /* 2530 * This makes sure all current packets have passed through 2531 * netfilter framework. Roll on, two-stage module 2532 * delete... 2533 */ 2534 synchronize_net(); 2535 i_see_dead_people: 2536 busy = 0; 2537 list_for_each_entry(net, net_exit_list, exit_list) { 2538 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2539 2540 iter_data.net = net; 2541 nf_ct_iterate_cleanup_net(kill_all, &iter_data); 2542 if (atomic_read(&cnet->count) != 0) 2543 busy = 1; 2544 } 2545 if (busy) { 2546 schedule(); 2547 goto i_see_dead_people; 2548 } 2549 2550 list_for_each_entry(net, net_exit_list, exit_list) { 2551 nf_conntrack_ecache_pernet_fini(net); 2552 nf_conntrack_expect_pernet_fini(net); 2553 free_percpu(net->ct.stat); 2554 } 2555 } 2556 2557 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 2558 { 2559 struct hlist_nulls_head *hash; 2560 unsigned int nr_slots, i; 2561 2562 if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head))) 2563 return NULL; 2564 2565 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 2566 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 2567 2568 hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL); 2569 2570 if (hash && nulls) 2571 for (i = 0; i < nr_slots; i++) 2572 INIT_HLIST_NULLS_HEAD(&hash[i], i); 2573 2574 return hash; 2575 } 2576 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 2577 2578 int nf_conntrack_hash_resize(unsigned int hashsize) 2579 { 2580 int i, bucket; 2581 unsigned int old_size; 2582 struct hlist_nulls_head *hash, *old_hash; 2583 struct nf_conntrack_tuple_hash *h; 2584 struct nf_conn *ct; 2585 2586 if (!hashsize) 2587 return -EINVAL; 2588 2589 hash = nf_ct_alloc_hashtable(&hashsize, 1); 2590 if (!hash) 2591 return -ENOMEM; 2592 2593 mutex_lock(&nf_conntrack_mutex); 2594 old_size = nf_conntrack_htable_size; 2595 if (old_size == hashsize) { 2596 mutex_unlock(&nf_conntrack_mutex); 2597 kvfree(hash); 2598 return 0; 2599 } 2600 2601 local_bh_disable(); 2602 nf_conntrack_all_lock(); 2603 write_seqcount_begin(&nf_conntrack_generation); 2604 2605 /* Lookups in the old hash might happen in parallel, which means we 2606 * might get false negatives during connection lookup. New connections 2607 * created because of a false negative won't make it into the hash 2608 * though since that required taking the locks. 2609 */ 2610 2611 for (i = 0; i < nf_conntrack_htable_size; i++) { 2612 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) { 2613 unsigned int zone_id; 2614 2615 h = hlist_nulls_entry(nf_conntrack_hash[i].first, 2616 struct nf_conntrack_tuple_hash, hnnode); 2617 ct = nf_ct_tuplehash_to_ctrack(h); 2618 hlist_nulls_del_rcu(&h->hnnode); 2619 2620 zone_id = nf_ct_zone_id(nf_ct_zone(ct), NF_CT_DIRECTION(h)); 2621 bucket = __hash_conntrack(nf_ct_net(ct), 2622 &h->tuple, zone_id, hashsize); 2623 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 2624 } 2625 } 2626 old_hash = nf_conntrack_hash; 2627 2628 nf_conntrack_hash = hash; 2629 nf_conntrack_htable_size = hashsize; 2630 2631 write_seqcount_end(&nf_conntrack_generation); 2632 nf_conntrack_all_unlock(); 2633 local_bh_enable(); 2634 2635 mutex_unlock(&nf_conntrack_mutex); 2636 2637 synchronize_net(); 2638 kvfree(old_hash); 2639 return 0; 2640 } 2641 2642 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp) 2643 { 2644 unsigned int hashsize; 2645 int rc; 2646 2647 if (current->nsproxy->net_ns != &init_net) 2648 return -EOPNOTSUPP; 2649 2650 /* On boot, we can set this without any fancy locking. */ 2651 if (!nf_conntrack_hash) 2652 return param_set_uint(val, kp); 2653 2654 rc = kstrtouint(val, 0, &hashsize); 2655 if (rc) 2656 return rc; 2657 2658 return nf_conntrack_hash_resize(hashsize); 2659 } 2660 2661 int nf_conntrack_init_start(void) 2662 { 2663 unsigned long nr_pages = totalram_pages(); 2664 int max_factor = 8; 2665 int ret = -ENOMEM; 2666 int i; 2667 2668 seqcount_spinlock_init(&nf_conntrack_generation, 2669 &nf_conntrack_locks_all_lock); 2670 2671 for (i = 0; i < CONNTRACK_LOCKS; i++) 2672 spin_lock_init(&nf_conntrack_locks[i]); 2673 2674 if (!nf_conntrack_htable_size) { 2675 nf_conntrack_htable_size 2676 = (((nr_pages << PAGE_SHIFT) / 16384) 2677 / sizeof(struct hlist_head)); 2678 if (BITS_PER_LONG >= 64 && 2679 nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE))) 2680 nf_conntrack_htable_size = 262144; 2681 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 2682 nf_conntrack_htable_size = 65536; 2683 2684 if (nf_conntrack_htable_size < 1024) 2685 nf_conntrack_htable_size = 1024; 2686 /* Use a max. factor of one by default to keep the average 2687 * hash chain length at 2 entries. Each entry has to be added 2688 * twice (once for original direction, once for reply). 2689 * When a table size is given we use the old value of 8 to 2690 * avoid implicit reduction of the max entries setting. 2691 */ 2692 max_factor = 1; 2693 } 2694 2695 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1); 2696 if (!nf_conntrack_hash) 2697 return -ENOMEM; 2698 2699 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 2700 2701 nf_conntrack_cachep = kmem_cache_create("nf_conntrack", 2702 sizeof(struct nf_conn), 2703 NFCT_INFOMASK + 1, 2704 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL); 2705 if (!nf_conntrack_cachep) 2706 goto err_cachep; 2707 2708 ret = nf_conntrack_expect_init(); 2709 if (ret < 0) 2710 goto err_expect; 2711 2712 ret = nf_conntrack_helper_init(); 2713 if (ret < 0) 2714 goto err_helper; 2715 2716 ret = nf_conntrack_proto_init(); 2717 if (ret < 0) 2718 goto err_proto; 2719 2720 conntrack_gc_work_init(&conntrack_gc_work); 2721 queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ); 2722 2723 ret = register_nf_conntrack_bpf(); 2724 if (ret < 0) 2725 goto err_kfunc; 2726 2727 return 0; 2728 2729 err_kfunc: 2730 cancel_delayed_work_sync(&conntrack_gc_work.dwork); 2731 nf_conntrack_proto_fini(); 2732 err_proto: 2733 nf_conntrack_helper_fini(); 2734 err_helper: 2735 nf_conntrack_expect_fini(); 2736 err_expect: 2737 kmem_cache_destroy(nf_conntrack_cachep); 2738 err_cachep: 2739 kvfree(nf_conntrack_hash); 2740 return ret; 2741 } 2742 2743 static const struct nf_ct_hook nf_conntrack_hook = { 2744 .update = nf_conntrack_update, 2745 .destroy = nf_ct_destroy, 2746 .get_tuple_skb = nf_conntrack_get_tuple_skb, 2747 .attach = nf_conntrack_attach, 2748 }; 2749 2750 void nf_conntrack_init_end(void) 2751 { 2752 RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook); 2753 } 2754 2755 /* 2756 * We need to use special "null" values, not used in hash table 2757 */ 2758 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 2759 2760 int nf_conntrack_init_net(struct net *net) 2761 { 2762 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2763 int ret = -ENOMEM; 2764 2765 BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER); 2766 BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS); 2767 atomic_set(&cnet->count, 0); 2768 2769 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 2770 if (!net->ct.stat) 2771 return ret; 2772 2773 ret = nf_conntrack_expect_pernet_init(net); 2774 if (ret < 0) 2775 goto err_expect; 2776 2777 nf_conntrack_acct_pernet_init(net); 2778 nf_conntrack_tstamp_pernet_init(net); 2779 nf_conntrack_ecache_pernet_init(net); 2780 nf_conntrack_helper_pernet_init(net); 2781 nf_conntrack_proto_pernet_init(net); 2782 2783 return 0; 2784 2785 err_expect: 2786 free_percpu(net->ct.stat); 2787 return ret; 2788 } 2789