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 /* must be called with local_bh_disable */ 529 static void nf_ct_add_to_dying_list(struct nf_conn *ct) 530 { 531 struct ct_pcpu *pcpu; 532 533 /* add this conntrack to the (per cpu) dying list */ 534 ct->cpu = smp_processor_id(); 535 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu); 536 537 spin_lock(&pcpu->lock); 538 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 539 &pcpu->dying); 540 spin_unlock(&pcpu->lock); 541 } 542 543 /* must be called with local_bh_disable */ 544 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct) 545 { 546 struct ct_pcpu *pcpu; 547 548 /* add this conntrack to the (per cpu) unconfirmed list */ 549 ct->cpu = smp_processor_id(); 550 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu); 551 552 spin_lock(&pcpu->lock); 553 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 554 &pcpu->unconfirmed); 555 spin_unlock(&pcpu->lock); 556 } 557 558 /* must be called with local_bh_disable */ 559 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct) 560 { 561 struct ct_pcpu *pcpu; 562 563 /* We overload first tuple to link into unconfirmed or dying list.*/ 564 pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu); 565 566 spin_lock(&pcpu->lock); 567 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 568 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 569 spin_unlock(&pcpu->lock); 570 } 571 572 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK) 573 574 /* Released via nf_ct_destroy() */ 575 struct nf_conn *nf_ct_tmpl_alloc(struct net *net, 576 const struct nf_conntrack_zone *zone, 577 gfp_t flags) 578 { 579 struct nf_conn *tmpl, *p; 580 581 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) { 582 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags); 583 if (!tmpl) 584 return NULL; 585 586 p = tmpl; 587 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p); 588 if (tmpl != p) { 589 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p); 590 tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p; 591 } 592 } else { 593 tmpl = kzalloc(sizeof(*tmpl), flags); 594 if (!tmpl) 595 return NULL; 596 } 597 598 tmpl->status = IPS_TEMPLATE; 599 write_pnet(&tmpl->ct_net, net); 600 nf_ct_zone_add(tmpl, zone); 601 refcount_set(&tmpl->ct_general.use, 1); 602 603 return tmpl; 604 } 605 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc); 606 607 void nf_ct_tmpl_free(struct nf_conn *tmpl) 608 { 609 kfree(tmpl->ext); 610 611 if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) 612 kfree((char *)tmpl - tmpl->proto.tmpl_padto); 613 else 614 kfree(tmpl); 615 } 616 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free); 617 618 static void destroy_gre_conntrack(struct nf_conn *ct) 619 { 620 #ifdef CONFIG_NF_CT_PROTO_GRE 621 struct nf_conn *master = ct->master; 622 623 if (master) 624 nf_ct_gre_keymap_destroy(master); 625 #endif 626 } 627 628 void nf_ct_destroy(struct nf_conntrack *nfct) 629 { 630 struct nf_conn *ct = (struct nf_conn *)nfct; 631 632 pr_debug("%s(%p)\n", __func__, ct); 633 WARN_ON(refcount_read(&nfct->use) != 0); 634 635 if (unlikely(nf_ct_is_template(ct))) { 636 nf_ct_tmpl_free(ct); 637 return; 638 } 639 640 if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE)) 641 destroy_gre_conntrack(ct); 642 643 local_bh_disable(); 644 /* Expectations will have been removed in clean_from_lists, 645 * except TFTP can create an expectation on the first packet, 646 * before connection is in the list, so we need to clean here, 647 * too. 648 */ 649 nf_ct_remove_expectations(ct); 650 651 nf_ct_del_from_dying_or_unconfirmed_list(ct); 652 653 local_bh_enable(); 654 655 if (ct->master) 656 nf_ct_put(ct->master); 657 658 pr_debug("%s: returning ct=%p to slab\n", __func__, ct); 659 nf_conntrack_free(ct); 660 } 661 EXPORT_SYMBOL(nf_ct_destroy); 662 663 static void nf_ct_delete_from_lists(struct nf_conn *ct) 664 { 665 struct net *net = nf_ct_net(ct); 666 unsigned int hash, reply_hash; 667 unsigned int sequence; 668 669 nf_ct_helper_destroy(ct); 670 671 local_bh_disable(); 672 do { 673 sequence = read_seqcount_begin(&nf_conntrack_generation); 674 hash = hash_conntrack(net, 675 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 676 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL)); 677 reply_hash = hash_conntrack(net, 678 &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 679 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); 680 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); 681 682 clean_from_lists(ct); 683 nf_conntrack_double_unlock(hash, reply_hash); 684 685 nf_ct_add_to_dying_list(ct); 686 687 local_bh_enable(); 688 } 689 690 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report) 691 { 692 struct nf_conn_tstamp *tstamp; 693 struct net *net; 694 695 if (test_and_set_bit(IPS_DYING_BIT, &ct->status)) 696 return false; 697 698 tstamp = nf_conn_tstamp_find(ct); 699 if (tstamp) { 700 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp; 701 702 tstamp->stop = ktime_get_real_ns(); 703 if (timeout < 0) 704 tstamp->stop -= jiffies_to_nsecs(-timeout); 705 } 706 707 if (nf_conntrack_event_report(IPCT_DESTROY, ct, 708 portid, report) < 0) { 709 /* destroy event was not delivered. nf_ct_put will 710 * be done by event cache worker on redelivery. 711 */ 712 nf_ct_delete_from_lists(ct); 713 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL); 714 return false; 715 } 716 717 net = nf_ct_net(ct); 718 if (nf_conntrack_ecache_dwork_pending(net)) 719 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT); 720 nf_ct_delete_from_lists(ct); 721 nf_ct_put(ct); 722 return true; 723 } 724 EXPORT_SYMBOL_GPL(nf_ct_delete); 725 726 static inline bool 727 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h, 728 const struct nf_conntrack_tuple *tuple, 729 const struct nf_conntrack_zone *zone, 730 const struct net *net) 731 { 732 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); 733 734 /* A conntrack can be recreated with the equal tuple, 735 * so we need to check that the conntrack is confirmed 736 */ 737 return nf_ct_tuple_equal(tuple, &h->tuple) && 738 nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) && 739 nf_ct_is_confirmed(ct) && 740 net_eq(net, nf_ct_net(ct)); 741 } 742 743 static inline bool 744 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2) 745 { 746 return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 747 &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) && 748 nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple, 749 &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) && 750 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) && 751 nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) && 752 net_eq(nf_ct_net(ct1), nf_ct_net(ct2)); 753 } 754 755 /* caller must hold rcu readlock and none of the nf_conntrack_locks */ 756 static void nf_ct_gc_expired(struct nf_conn *ct) 757 { 758 if (!refcount_inc_not_zero(&ct->ct_general.use)) 759 return; 760 761 if (nf_ct_should_gc(ct)) 762 nf_ct_kill(ct); 763 764 nf_ct_put(ct); 765 } 766 767 /* 768 * Warning : 769 * - Caller must take a reference on returned object 770 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 771 */ 772 static struct nf_conntrack_tuple_hash * 773 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone, 774 const struct nf_conntrack_tuple *tuple, u32 hash) 775 { 776 struct nf_conntrack_tuple_hash *h; 777 struct hlist_nulls_head *ct_hash; 778 struct hlist_nulls_node *n; 779 unsigned int bucket, hsize; 780 781 begin: 782 nf_conntrack_get_ht(&ct_hash, &hsize); 783 bucket = reciprocal_scale(hash, hsize); 784 785 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) { 786 struct nf_conn *ct; 787 788 ct = nf_ct_tuplehash_to_ctrack(h); 789 if (nf_ct_is_expired(ct)) { 790 nf_ct_gc_expired(ct); 791 continue; 792 } 793 794 if (nf_ct_key_equal(h, tuple, zone, net)) 795 return h; 796 } 797 /* 798 * if the nulls value we got at the end of this lookup is 799 * not the expected one, we must restart lookup. 800 * We probably met an item that was moved to another chain. 801 */ 802 if (get_nulls_value(n) != bucket) { 803 NF_CT_STAT_INC_ATOMIC(net, search_restart); 804 goto begin; 805 } 806 807 return NULL; 808 } 809 810 /* Find a connection corresponding to a tuple. */ 811 static struct nf_conntrack_tuple_hash * 812 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, 813 const struct nf_conntrack_tuple *tuple, u32 hash) 814 { 815 struct nf_conntrack_tuple_hash *h; 816 struct nf_conn *ct; 817 818 rcu_read_lock(); 819 820 h = ____nf_conntrack_find(net, zone, tuple, hash); 821 if (h) { 822 /* We have a candidate that matches the tuple we're interested 823 * in, try to obtain a reference and re-check tuple 824 */ 825 ct = nf_ct_tuplehash_to_ctrack(h); 826 if (likely(refcount_inc_not_zero(&ct->ct_general.use))) { 827 if (likely(nf_ct_key_equal(h, tuple, zone, net))) 828 goto found; 829 830 /* TYPESAFE_BY_RCU recycled the candidate */ 831 nf_ct_put(ct); 832 } 833 834 h = NULL; 835 } 836 found: 837 rcu_read_unlock(); 838 839 return h; 840 } 841 842 struct nf_conntrack_tuple_hash * 843 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone, 844 const struct nf_conntrack_tuple *tuple) 845 { 846 unsigned int rid, zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL); 847 struct nf_conntrack_tuple_hash *thash; 848 849 thash = __nf_conntrack_find_get(net, zone, tuple, 850 hash_conntrack_raw(tuple, zone_id, net)); 851 852 if (thash) 853 return thash; 854 855 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY); 856 if (rid != zone_id) 857 return __nf_conntrack_find_get(net, zone, tuple, 858 hash_conntrack_raw(tuple, rid, net)); 859 return thash; 860 } 861 EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 862 863 static void __nf_conntrack_hash_insert(struct nf_conn *ct, 864 unsigned int hash, 865 unsigned int reply_hash) 866 { 867 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 868 &nf_conntrack_hash[hash]); 869 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 870 &nf_conntrack_hash[reply_hash]); 871 } 872 873 int 874 nf_conntrack_hash_check_insert(struct nf_conn *ct) 875 { 876 const struct nf_conntrack_zone *zone; 877 struct net *net = nf_ct_net(ct); 878 unsigned int hash, reply_hash; 879 struct nf_conntrack_tuple_hash *h; 880 struct hlist_nulls_node *n; 881 unsigned int max_chainlen; 882 unsigned int chainlen = 0; 883 unsigned int sequence; 884 int err = -EEXIST; 885 886 zone = nf_ct_zone(ct); 887 888 local_bh_disable(); 889 do { 890 sequence = read_seqcount_begin(&nf_conntrack_generation); 891 hash = hash_conntrack(net, 892 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 893 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL)); 894 reply_hash = hash_conntrack(net, 895 &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 896 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); 897 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); 898 899 max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN); 900 901 /* See if there's one in the list already, including reverse */ 902 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) { 903 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 904 zone, net)) 905 goto out; 906 907 if (chainlen++ > max_chainlen) 908 goto chaintoolong; 909 } 910 911 chainlen = 0; 912 913 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) { 914 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 915 zone, net)) 916 goto out; 917 if (chainlen++ > max_chainlen) 918 goto chaintoolong; 919 } 920 921 smp_wmb(); 922 /* The caller holds a reference to this object */ 923 refcount_set(&ct->ct_general.use, 2); 924 __nf_conntrack_hash_insert(ct, hash, reply_hash); 925 nf_conntrack_double_unlock(hash, reply_hash); 926 NF_CT_STAT_INC(net, insert); 927 local_bh_enable(); 928 return 0; 929 chaintoolong: 930 NF_CT_STAT_INC(net, chaintoolong); 931 err = -ENOSPC; 932 out: 933 nf_conntrack_double_unlock(hash, reply_hash); 934 local_bh_enable(); 935 return err; 936 } 937 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert); 938 939 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets, 940 unsigned int bytes) 941 { 942 struct nf_conn_acct *acct; 943 944 acct = nf_conn_acct_find(ct); 945 if (acct) { 946 struct nf_conn_counter *counter = acct->counter; 947 948 atomic64_add(packets, &counter[dir].packets); 949 atomic64_add(bytes, &counter[dir].bytes); 950 } 951 } 952 EXPORT_SYMBOL_GPL(nf_ct_acct_add); 953 954 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo, 955 const struct nf_conn *loser_ct) 956 { 957 struct nf_conn_acct *acct; 958 959 acct = nf_conn_acct_find(loser_ct); 960 if (acct) { 961 struct nf_conn_counter *counter = acct->counter; 962 unsigned int bytes; 963 964 /* u32 should be fine since we must have seen one packet. */ 965 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes); 966 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes); 967 } 968 } 969 970 static void __nf_conntrack_insert_prepare(struct nf_conn *ct) 971 { 972 struct nf_conn_tstamp *tstamp; 973 974 refcount_inc(&ct->ct_general.use); 975 ct->status |= IPS_CONFIRMED; 976 977 /* set conntrack timestamp, if enabled. */ 978 tstamp = nf_conn_tstamp_find(ct); 979 if (tstamp) 980 tstamp->start = ktime_get_real_ns(); 981 } 982 983 /* caller must hold locks to prevent concurrent changes */ 984 static int __nf_ct_resolve_clash(struct sk_buff *skb, 985 struct nf_conntrack_tuple_hash *h) 986 { 987 /* This is the conntrack entry already in hashes that won race. */ 988 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); 989 enum ip_conntrack_info ctinfo; 990 struct nf_conn *loser_ct; 991 992 loser_ct = nf_ct_get(skb, &ctinfo); 993 994 if (nf_ct_is_dying(ct)) 995 return NF_DROP; 996 997 if (((ct->status & IPS_NAT_DONE_MASK) == 0) || 998 nf_ct_match(ct, loser_ct)) { 999 struct net *net = nf_ct_net(ct); 1000 1001 nf_conntrack_get(&ct->ct_general); 1002 1003 nf_ct_acct_merge(ct, ctinfo, loser_ct); 1004 nf_ct_add_to_dying_list(loser_ct); 1005 nf_ct_put(loser_ct); 1006 nf_ct_set(skb, ct, ctinfo); 1007 1008 NF_CT_STAT_INC(net, clash_resolve); 1009 return NF_ACCEPT; 1010 } 1011 1012 return NF_DROP; 1013 } 1014 1015 /** 1016 * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry 1017 * 1018 * @skb: skb that causes the collision 1019 * @repl_idx: hash slot for reply direction 1020 * 1021 * Called when origin or reply direction had a clash. 1022 * The skb can be handled without packet drop provided the reply direction 1023 * is unique or there the existing entry has the identical tuple in both 1024 * directions. 1025 * 1026 * Caller must hold conntrack table locks to prevent concurrent updates. 1027 * 1028 * Returns NF_DROP if the clash could not be handled. 1029 */ 1030 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx) 1031 { 1032 struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb); 1033 const struct nf_conntrack_zone *zone; 1034 struct nf_conntrack_tuple_hash *h; 1035 struct hlist_nulls_node *n; 1036 struct net *net; 1037 1038 zone = nf_ct_zone(loser_ct); 1039 net = nf_ct_net(loser_ct); 1040 1041 /* Reply direction must never result in a clash, unless both origin 1042 * and reply tuples are identical. 1043 */ 1044 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) { 1045 if (nf_ct_key_equal(h, 1046 &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple, 1047 zone, net)) 1048 return __nf_ct_resolve_clash(skb, h); 1049 } 1050 1051 /* We want the clashing entry to go away real soon: 1 second timeout. */ 1052 WRITE_ONCE(loser_ct->timeout, nfct_time_stamp + HZ); 1053 1054 /* IPS_NAT_CLASH removes the entry automatically on the first 1055 * reply. Also prevents UDP tracker from moving the entry to 1056 * ASSURED state, i.e. the entry can always be evicted under 1057 * pressure. 1058 */ 1059 loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH; 1060 1061 __nf_conntrack_insert_prepare(loser_ct); 1062 1063 /* fake add for ORIGINAL dir: we want lookups to only find the entry 1064 * already in the table. This also hides the clashing entry from 1065 * ctnetlink iteration, i.e. conntrack -L won't show them. 1066 */ 1067 hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 1068 1069 hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 1070 &nf_conntrack_hash[repl_idx]); 1071 1072 NF_CT_STAT_INC(net, clash_resolve); 1073 return NF_ACCEPT; 1074 } 1075 1076 /** 1077 * nf_ct_resolve_clash - attempt to handle clash without packet drop 1078 * 1079 * @skb: skb that causes the clash 1080 * @h: tuplehash of the clashing entry already in table 1081 * @reply_hash: hash slot for reply direction 1082 * 1083 * A conntrack entry can be inserted to the connection tracking table 1084 * if there is no existing entry with an identical tuple. 1085 * 1086 * If there is one, @skb (and the assocated, unconfirmed conntrack) has 1087 * to be dropped. In case @skb is retransmitted, next conntrack lookup 1088 * will find the already-existing entry. 1089 * 1090 * The major problem with such packet drop is the extra delay added by 1091 * the packet loss -- it will take some time for a retransmit to occur 1092 * (or the sender to time out when waiting for a reply). 1093 * 1094 * This function attempts to handle the situation without packet drop. 1095 * 1096 * If @skb has no NAT transformation or if the colliding entries are 1097 * exactly the same, only the to-be-confirmed conntrack entry is discarded 1098 * and @skb is associated with the conntrack entry already in the table. 1099 * 1100 * Failing that, the new, unconfirmed conntrack is still added to the table 1101 * provided that the collision only occurs in the ORIGINAL direction. 1102 * The new entry will be added only in the non-clashing REPLY direction, 1103 * so packets in the ORIGINAL direction will continue to match the existing 1104 * entry. The new entry will also have a fixed timeout so it expires -- 1105 * due to the collision, it will only see reply traffic. 1106 * 1107 * Returns NF_DROP if the clash could not be resolved. 1108 */ 1109 static __cold noinline int 1110 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h, 1111 u32 reply_hash) 1112 { 1113 /* This is the conntrack entry already in hashes that won race. */ 1114 struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); 1115 const struct nf_conntrack_l4proto *l4proto; 1116 enum ip_conntrack_info ctinfo; 1117 struct nf_conn *loser_ct; 1118 struct net *net; 1119 int ret; 1120 1121 loser_ct = nf_ct_get(skb, &ctinfo); 1122 net = nf_ct_net(loser_ct); 1123 1124 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct)); 1125 if (!l4proto->allow_clash) 1126 goto drop; 1127 1128 ret = __nf_ct_resolve_clash(skb, h); 1129 if (ret == NF_ACCEPT) 1130 return ret; 1131 1132 ret = nf_ct_resolve_clash_harder(skb, reply_hash); 1133 if (ret == NF_ACCEPT) 1134 return ret; 1135 1136 drop: 1137 nf_ct_add_to_dying_list(loser_ct); 1138 NF_CT_STAT_INC(net, drop); 1139 NF_CT_STAT_INC(net, insert_failed); 1140 return NF_DROP; 1141 } 1142 1143 /* Confirm a connection given skb; places it in hash table */ 1144 int 1145 __nf_conntrack_confirm(struct sk_buff *skb) 1146 { 1147 unsigned int chainlen = 0, sequence, max_chainlen; 1148 const struct nf_conntrack_zone *zone; 1149 unsigned int hash, reply_hash; 1150 struct nf_conntrack_tuple_hash *h; 1151 struct nf_conn *ct; 1152 struct nf_conn_help *help; 1153 struct hlist_nulls_node *n; 1154 enum ip_conntrack_info ctinfo; 1155 struct net *net; 1156 int ret = NF_DROP; 1157 1158 ct = nf_ct_get(skb, &ctinfo); 1159 net = nf_ct_net(ct); 1160 1161 /* ipt_REJECT uses nf_conntrack_attach to attach related 1162 ICMP/TCP RST packets in other direction. Actual packet 1163 which created connection will be IP_CT_NEW or for an 1164 expected connection, IP_CT_RELATED. */ 1165 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 1166 return NF_ACCEPT; 1167 1168 zone = nf_ct_zone(ct); 1169 local_bh_disable(); 1170 1171 do { 1172 sequence = read_seqcount_begin(&nf_conntrack_generation); 1173 /* reuse the hash saved before */ 1174 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev; 1175 hash = scale_hash(hash); 1176 reply_hash = hash_conntrack(net, 1177 &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 1178 nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY)); 1179 } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence)); 1180 1181 /* We're not in hash table, and we refuse to set up related 1182 * connections for unconfirmed conns. But packet copies and 1183 * REJECT will give spurious warnings here. 1184 */ 1185 1186 /* Another skb with the same unconfirmed conntrack may 1187 * win the race. This may happen for bridge(br_flood) 1188 * or broadcast/multicast packets do skb_clone with 1189 * unconfirmed conntrack. 1190 */ 1191 if (unlikely(nf_ct_is_confirmed(ct))) { 1192 WARN_ON_ONCE(1); 1193 nf_conntrack_double_unlock(hash, reply_hash); 1194 local_bh_enable(); 1195 return NF_DROP; 1196 } 1197 1198 pr_debug("Confirming conntrack %p\n", ct); 1199 /* We have to check the DYING flag after unlink to prevent 1200 * a race against nf_ct_get_next_corpse() possibly called from 1201 * user context, else we insert an already 'dead' hash, blocking 1202 * further use of that particular connection -JM. 1203 */ 1204 nf_ct_del_from_dying_or_unconfirmed_list(ct); 1205 1206 if (unlikely(nf_ct_is_dying(ct))) { 1207 nf_ct_add_to_dying_list(ct); 1208 NF_CT_STAT_INC(net, insert_failed); 1209 goto dying; 1210 } 1211 1212 max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN); 1213 /* See if there's one in the list already, including reverse: 1214 NAT could have grabbed it without realizing, since we're 1215 not in the hash. If there is, we lost race. */ 1216 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) { 1217 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 1218 zone, net)) 1219 goto out; 1220 if (chainlen++ > max_chainlen) 1221 goto chaintoolong; 1222 } 1223 1224 chainlen = 0; 1225 hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) { 1226 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, 1227 zone, net)) 1228 goto out; 1229 if (chainlen++ > max_chainlen) { 1230 chaintoolong: 1231 nf_ct_add_to_dying_list(ct); 1232 NF_CT_STAT_INC(net, chaintoolong); 1233 NF_CT_STAT_INC(net, insert_failed); 1234 ret = NF_DROP; 1235 goto dying; 1236 } 1237 } 1238 1239 /* Timer relative to confirmation time, not original 1240 setting time, otherwise we'd get timer wrap in 1241 weird delay cases. */ 1242 ct->timeout += nfct_time_stamp; 1243 1244 __nf_conntrack_insert_prepare(ct); 1245 1246 /* Since the lookup is lockless, hash insertion must be done after 1247 * starting the timer and setting the CONFIRMED bit. The RCU barriers 1248 * guarantee that no other CPU can find the conntrack before the above 1249 * stores are visible. 1250 */ 1251 __nf_conntrack_hash_insert(ct, hash, reply_hash); 1252 nf_conntrack_double_unlock(hash, reply_hash); 1253 local_bh_enable(); 1254 1255 help = nfct_help(ct); 1256 if (help && help->helper) 1257 nf_conntrack_event_cache(IPCT_HELPER, ct); 1258 1259 nf_conntrack_event_cache(master_ct(ct) ? 1260 IPCT_RELATED : IPCT_NEW, ct); 1261 return NF_ACCEPT; 1262 1263 out: 1264 ret = nf_ct_resolve_clash(skb, h, reply_hash); 1265 dying: 1266 nf_conntrack_double_unlock(hash, reply_hash); 1267 local_bh_enable(); 1268 return ret; 1269 } 1270 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 1271 1272 /* Returns true if a connection correspondings to the tuple (required 1273 for NAT). */ 1274 int 1275 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 1276 const struct nf_conn *ignored_conntrack) 1277 { 1278 struct net *net = nf_ct_net(ignored_conntrack); 1279 const struct nf_conntrack_zone *zone; 1280 struct nf_conntrack_tuple_hash *h; 1281 struct hlist_nulls_head *ct_hash; 1282 unsigned int hash, hsize; 1283 struct hlist_nulls_node *n; 1284 struct nf_conn *ct; 1285 1286 zone = nf_ct_zone(ignored_conntrack); 1287 1288 rcu_read_lock(); 1289 begin: 1290 nf_conntrack_get_ht(&ct_hash, &hsize); 1291 hash = __hash_conntrack(net, tuple, nf_ct_zone_id(zone, IP_CT_DIR_REPLY), hsize); 1292 1293 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) { 1294 ct = nf_ct_tuplehash_to_ctrack(h); 1295 1296 if (ct == ignored_conntrack) 1297 continue; 1298 1299 if (nf_ct_is_expired(ct)) { 1300 nf_ct_gc_expired(ct); 1301 continue; 1302 } 1303 1304 if (nf_ct_key_equal(h, tuple, zone, net)) { 1305 /* Tuple is taken already, so caller will need to find 1306 * a new source port to use. 1307 * 1308 * Only exception: 1309 * If the *original tuples* are identical, then both 1310 * conntracks refer to the same flow. 1311 * This is a rare situation, it can occur e.g. when 1312 * more than one UDP packet is sent from same socket 1313 * in different threads. 1314 * 1315 * Let nf_ct_resolve_clash() deal with this later. 1316 */ 1317 if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 1318 &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) && 1319 nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) 1320 continue; 1321 1322 NF_CT_STAT_INC_ATOMIC(net, found); 1323 rcu_read_unlock(); 1324 return 1; 1325 } 1326 } 1327 1328 if (get_nulls_value(n) != hash) { 1329 NF_CT_STAT_INC_ATOMIC(net, search_restart); 1330 goto begin; 1331 } 1332 1333 rcu_read_unlock(); 1334 1335 return 0; 1336 } 1337 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 1338 1339 #define NF_CT_EVICTION_RANGE 8 1340 1341 /* There's a small race here where we may free a just-assured 1342 connection. Too bad: we're in trouble anyway. */ 1343 static unsigned int early_drop_list(struct net *net, 1344 struct hlist_nulls_head *head) 1345 { 1346 struct nf_conntrack_tuple_hash *h; 1347 struct hlist_nulls_node *n; 1348 unsigned int drops = 0; 1349 struct nf_conn *tmp; 1350 1351 hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) { 1352 tmp = nf_ct_tuplehash_to_ctrack(h); 1353 1354 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) 1355 continue; 1356 1357 if (nf_ct_is_expired(tmp)) { 1358 nf_ct_gc_expired(tmp); 1359 continue; 1360 } 1361 1362 if (test_bit(IPS_ASSURED_BIT, &tmp->status) || 1363 !net_eq(nf_ct_net(tmp), net) || 1364 nf_ct_is_dying(tmp)) 1365 continue; 1366 1367 if (!refcount_inc_not_zero(&tmp->ct_general.use)) 1368 continue; 1369 1370 /* kill only if still in same netns -- might have moved due to 1371 * SLAB_TYPESAFE_BY_RCU rules. 1372 * 1373 * We steal the timer reference. If that fails timer has 1374 * already fired or someone else deleted it. Just drop ref 1375 * and move to next entry. 1376 */ 1377 if (net_eq(nf_ct_net(tmp), net) && 1378 nf_ct_is_confirmed(tmp) && 1379 nf_ct_delete(tmp, 0, 0)) 1380 drops++; 1381 1382 nf_ct_put(tmp); 1383 } 1384 1385 return drops; 1386 } 1387 1388 static noinline int early_drop(struct net *net, unsigned int hash) 1389 { 1390 unsigned int i, bucket; 1391 1392 for (i = 0; i < NF_CT_EVICTION_RANGE; i++) { 1393 struct hlist_nulls_head *ct_hash; 1394 unsigned int hsize, drops; 1395 1396 rcu_read_lock(); 1397 nf_conntrack_get_ht(&ct_hash, &hsize); 1398 if (!i) 1399 bucket = reciprocal_scale(hash, hsize); 1400 else 1401 bucket = (bucket + 1) % hsize; 1402 1403 drops = early_drop_list(net, &ct_hash[bucket]); 1404 rcu_read_unlock(); 1405 1406 if (drops) { 1407 NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops); 1408 return true; 1409 } 1410 } 1411 1412 return false; 1413 } 1414 1415 static bool gc_worker_skip_ct(const struct nf_conn *ct) 1416 { 1417 return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct); 1418 } 1419 1420 static bool gc_worker_can_early_drop(const struct nf_conn *ct) 1421 { 1422 const struct nf_conntrack_l4proto *l4proto; 1423 1424 if (!test_bit(IPS_ASSURED_BIT, &ct->status)) 1425 return true; 1426 1427 l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct)); 1428 if (l4proto->can_early_drop && l4proto->can_early_drop(ct)) 1429 return true; 1430 1431 return false; 1432 } 1433 1434 static void gc_worker(struct work_struct *work) 1435 { 1436 unsigned int i, hashsz, nf_conntrack_max95 = 0; 1437 u32 end_time, start_time = nfct_time_stamp; 1438 struct conntrack_gc_work *gc_work; 1439 unsigned int expired_count = 0; 1440 unsigned long next_run; 1441 s32 delta_time; 1442 1443 gc_work = container_of(work, struct conntrack_gc_work, dwork.work); 1444 1445 i = gc_work->next_bucket; 1446 if (gc_work->early_drop) 1447 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u; 1448 1449 if (i == 0) { 1450 gc_work->avg_timeout = GC_SCAN_INTERVAL_INIT; 1451 gc_work->start_time = start_time; 1452 } 1453 1454 next_run = gc_work->avg_timeout; 1455 1456 end_time = start_time + GC_SCAN_MAX_DURATION; 1457 1458 do { 1459 struct nf_conntrack_tuple_hash *h; 1460 struct hlist_nulls_head *ct_hash; 1461 struct hlist_nulls_node *n; 1462 struct nf_conn *tmp; 1463 1464 rcu_read_lock(); 1465 1466 nf_conntrack_get_ht(&ct_hash, &hashsz); 1467 if (i >= hashsz) { 1468 rcu_read_unlock(); 1469 break; 1470 } 1471 1472 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) { 1473 struct nf_conntrack_net *cnet; 1474 unsigned long expires; 1475 struct net *net; 1476 1477 tmp = nf_ct_tuplehash_to_ctrack(h); 1478 1479 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) { 1480 nf_ct_offload_timeout(tmp); 1481 continue; 1482 } 1483 1484 if (expired_count > GC_SCAN_EXPIRED_MAX) { 1485 rcu_read_unlock(); 1486 1487 gc_work->next_bucket = i; 1488 gc_work->avg_timeout = next_run; 1489 1490 delta_time = nfct_time_stamp - gc_work->start_time; 1491 1492 /* re-sched immediately if total cycle time is exceeded */ 1493 next_run = delta_time < (s32)GC_SCAN_INTERVAL_MAX; 1494 goto early_exit; 1495 } 1496 1497 if (nf_ct_is_expired(tmp)) { 1498 nf_ct_gc_expired(tmp); 1499 expired_count++; 1500 continue; 1501 } 1502 1503 expires = clamp(nf_ct_expires(tmp), GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_CLAMP); 1504 next_run += expires; 1505 next_run /= 2u; 1506 1507 if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp)) 1508 continue; 1509 1510 net = nf_ct_net(tmp); 1511 cnet = nf_ct_pernet(net); 1512 if (atomic_read(&cnet->count) < nf_conntrack_max95) 1513 continue; 1514 1515 /* need to take reference to avoid possible races */ 1516 if (!refcount_inc_not_zero(&tmp->ct_general.use)) 1517 continue; 1518 1519 if (gc_worker_skip_ct(tmp)) { 1520 nf_ct_put(tmp); 1521 continue; 1522 } 1523 1524 if (gc_worker_can_early_drop(tmp)) { 1525 nf_ct_kill(tmp); 1526 expired_count++; 1527 } 1528 1529 nf_ct_put(tmp); 1530 } 1531 1532 /* could check get_nulls_value() here and restart if ct 1533 * was moved to another chain. But given gc is best-effort 1534 * we will just continue with next hash slot. 1535 */ 1536 rcu_read_unlock(); 1537 cond_resched(); 1538 i++; 1539 1540 delta_time = nfct_time_stamp - end_time; 1541 if (delta_time > 0 && i < hashsz) { 1542 gc_work->avg_timeout = next_run; 1543 gc_work->next_bucket = i; 1544 next_run = 0; 1545 goto early_exit; 1546 } 1547 } while (i < hashsz); 1548 1549 gc_work->next_bucket = 0; 1550 1551 next_run = clamp(next_run, GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_MAX); 1552 1553 delta_time = max_t(s32, nfct_time_stamp - gc_work->start_time, 1); 1554 if (next_run > (unsigned long)delta_time) 1555 next_run -= delta_time; 1556 else 1557 next_run = 1; 1558 1559 early_exit: 1560 if (gc_work->exiting) 1561 return; 1562 1563 if (next_run) 1564 gc_work->early_drop = false; 1565 1566 queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run); 1567 } 1568 1569 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work) 1570 { 1571 INIT_DELAYED_WORK(&gc_work->dwork, gc_worker); 1572 gc_work->exiting = false; 1573 } 1574 1575 static struct nf_conn * 1576 __nf_conntrack_alloc(struct net *net, 1577 const struct nf_conntrack_zone *zone, 1578 const struct nf_conntrack_tuple *orig, 1579 const struct nf_conntrack_tuple *repl, 1580 gfp_t gfp, u32 hash) 1581 { 1582 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 1583 unsigned int ct_count; 1584 struct nf_conn *ct; 1585 1586 /* We don't want any race condition at early drop stage */ 1587 ct_count = atomic_inc_return(&cnet->count); 1588 1589 if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) { 1590 if (!early_drop(net, hash)) { 1591 if (!conntrack_gc_work.early_drop) 1592 conntrack_gc_work.early_drop = true; 1593 atomic_dec(&cnet->count); 1594 net_warn_ratelimited("nf_conntrack: table full, dropping packet\n"); 1595 return ERR_PTR(-ENOMEM); 1596 } 1597 } 1598 1599 /* 1600 * Do not use kmem_cache_zalloc(), as this cache uses 1601 * SLAB_TYPESAFE_BY_RCU. 1602 */ 1603 ct = kmem_cache_alloc(nf_conntrack_cachep, gfp); 1604 if (ct == NULL) 1605 goto out; 1606 1607 spin_lock_init(&ct->lock); 1608 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 1609 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 1610 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 1611 /* save hash for reusing when confirming */ 1612 *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash; 1613 ct->status = 0; 1614 WRITE_ONCE(ct->timeout, 0); 1615 write_pnet(&ct->ct_net, net); 1616 memset_after(ct, 0, __nfct_init_offset); 1617 1618 nf_ct_zone_add(ct, zone); 1619 1620 /* Because we use RCU lookups, we set ct_general.use to zero before 1621 * this is inserted in any list. 1622 */ 1623 refcount_set(&ct->ct_general.use, 0); 1624 return ct; 1625 out: 1626 atomic_dec(&cnet->count); 1627 return ERR_PTR(-ENOMEM); 1628 } 1629 1630 struct nf_conn *nf_conntrack_alloc(struct net *net, 1631 const struct nf_conntrack_zone *zone, 1632 const struct nf_conntrack_tuple *orig, 1633 const struct nf_conntrack_tuple *repl, 1634 gfp_t gfp) 1635 { 1636 return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0); 1637 } 1638 EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 1639 1640 void nf_conntrack_free(struct nf_conn *ct) 1641 { 1642 struct net *net = nf_ct_net(ct); 1643 struct nf_conntrack_net *cnet; 1644 1645 /* A freed object has refcnt == 0, that's 1646 * the golden rule for SLAB_TYPESAFE_BY_RCU 1647 */ 1648 WARN_ON(refcount_read(&ct->ct_general.use) != 0); 1649 1650 if (ct->status & IPS_SRC_NAT_DONE) { 1651 const struct nf_nat_hook *nat_hook; 1652 1653 rcu_read_lock(); 1654 nat_hook = rcu_dereference(nf_nat_hook); 1655 if (nat_hook) 1656 nat_hook->remove_nat_bysrc(ct); 1657 rcu_read_unlock(); 1658 } 1659 1660 kfree(ct->ext); 1661 kmem_cache_free(nf_conntrack_cachep, ct); 1662 cnet = nf_ct_pernet(net); 1663 1664 smp_mb__before_atomic(); 1665 atomic_dec(&cnet->count); 1666 } 1667 EXPORT_SYMBOL_GPL(nf_conntrack_free); 1668 1669 1670 /* Allocate a new conntrack: we return -ENOMEM if classification 1671 failed due to stress. Otherwise it really is unclassifiable. */ 1672 static noinline struct nf_conntrack_tuple_hash * 1673 init_conntrack(struct net *net, struct nf_conn *tmpl, 1674 const struct nf_conntrack_tuple *tuple, 1675 struct sk_buff *skb, 1676 unsigned int dataoff, u32 hash) 1677 { 1678 struct nf_conn *ct; 1679 struct nf_conn_help *help; 1680 struct nf_conntrack_tuple repl_tuple; 1681 struct nf_conntrack_ecache *ecache; 1682 struct nf_conntrack_expect *exp = NULL; 1683 const struct nf_conntrack_zone *zone; 1684 struct nf_conn_timeout *timeout_ext; 1685 struct nf_conntrack_zone tmp; 1686 struct nf_conntrack_net *cnet; 1687 1688 if (!nf_ct_invert_tuple(&repl_tuple, tuple)) { 1689 pr_debug("Can't invert tuple.\n"); 1690 return NULL; 1691 } 1692 1693 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); 1694 ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC, 1695 hash); 1696 if (IS_ERR(ct)) 1697 return (struct nf_conntrack_tuple_hash *)ct; 1698 1699 if (!nf_ct_add_synproxy(ct, tmpl)) { 1700 nf_conntrack_free(ct); 1701 return ERR_PTR(-ENOMEM); 1702 } 1703 1704 timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; 1705 1706 if (timeout_ext) 1707 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout), 1708 GFP_ATOMIC); 1709 1710 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 1711 nf_ct_tstamp_ext_add(ct, GFP_ATOMIC); 1712 nf_ct_labels_ext_add(ct); 1713 1714 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 1715 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 1716 ecache ? ecache->expmask : 0, 1717 GFP_ATOMIC); 1718 1719 local_bh_disable(); 1720 cnet = nf_ct_pernet(net); 1721 if (cnet->expect_count) { 1722 spin_lock(&nf_conntrack_expect_lock); 1723 exp = nf_ct_find_expectation(net, zone, tuple); 1724 if (exp) { 1725 pr_debug("expectation arrives ct=%p exp=%p\n", 1726 ct, exp); 1727 /* Welcome, Mr. Bond. We've been expecting you... */ 1728 __set_bit(IPS_EXPECTED_BIT, &ct->status); 1729 /* exp->master safe, refcnt bumped in nf_ct_find_expectation */ 1730 ct->master = exp->master; 1731 if (exp->helper) { 1732 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 1733 if (help) 1734 rcu_assign_pointer(help->helper, exp->helper); 1735 } 1736 1737 #ifdef CONFIG_NF_CONNTRACK_MARK 1738 ct->mark = exp->master->mark; 1739 #endif 1740 #ifdef CONFIG_NF_CONNTRACK_SECMARK 1741 ct->secmark = exp->master->secmark; 1742 #endif 1743 NF_CT_STAT_INC(net, expect_new); 1744 } 1745 spin_unlock(&nf_conntrack_expect_lock); 1746 } 1747 if (!exp) 1748 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 1749 1750 /* Now it is inserted into the unconfirmed list, set refcount to 1. */ 1751 refcount_set(&ct->ct_general.use, 1); 1752 nf_ct_add_to_unconfirmed_list(ct); 1753 1754 local_bh_enable(); 1755 1756 if (exp) { 1757 if (exp->expectfn) 1758 exp->expectfn(ct, exp); 1759 nf_ct_expect_put(exp); 1760 } 1761 1762 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 1763 } 1764 1765 /* On success, returns 0, sets skb->_nfct | ctinfo */ 1766 static int 1767 resolve_normal_ct(struct nf_conn *tmpl, 1768 struct sk_buff *skb, 1769 unsigned int dataoff, 1770 u_int8_t protonum, 1771 const struct nf_hook_state *state) 1772 { 1773 const struct nf_conntrack_zone *zone; 1774 struct nf_conntrack_tuple tuple; 1775 struct nf_conntrack_tuple_hash *h; 1776 enum ip_conntrack_info ctinfo; 1777 struct nf_conntrack_zone tmp; 1778 u32 hash, zone_id, rid; 1779 struct nf_conn *ct; 1780 1781 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 1782 dataoff, state->pf, protonum, state->net, 1783 &tuple)) { 1784 pr_debug("Can't get tuple\n"); 1785 return 0; 1786 } 1787 1788 /* look for tuple match */ 1789 zone = nf_ct_zone_tmpl(tmpl, skb, &tmp); 1790 1791 zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL); 1792 hash = hash_conntrack_raw(&tuple, zone_id, state->net); 1793 h = __nf_conntrack_find_get(state->net, zone, &tuple, hash); 1794 1795 if (!h) { 1796 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY); 1797 if (zone_id != rid) { 1798 u32 tmp = hash_conntrack_raw(&tuple, rid, state->net); 1799 1800 h = __nf_conntrack_find_get(state->net, zone, &tuple, tmp); 1801 } 1802 } 1803 1804 if (!h) { 1805 h = init_conntrack(state->net, tmpl, &tuple, 1806 skb, dataoff, hash); 1807 if (!h) 1808 return 0; 1809 if (IS_ERR(h)) 1810 return PTR_ERR(h); 1811 } 1812 ct = nf_ct_tuplehash_to_ctrack(h); 1813 1814 /* It exists; we have (non-exclusive) reference. */ 1815 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 1816 ctinfo = IP_CT_ESTABLISHED_REPLY; 1817 } else { 1818 /* Once we've had two way comms, always ESTABLISHED. */ 1819 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 1820 pr_debug("normal packet for %p\n", ct); 1821 ctinfo = IP_CT_ESTABLISHED; 1822 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 1823 pr_debug("related packet for %p\n", ct); 1824 ctinfo = IP_CT_RELATED; 1825 } else { 1826 pr_debug("new packet for %p\n", ct); 1827 ctinfo = IP_CT_NEW; 1828 } 1829 } 1830 nf_ct_set(skb, ct, ctinfo); 1831 return 0; 1832 } 1833 1834 /* 1835 * icmp packets need special treatment to handle error messages that are 1836 * related to a connection. 1837 * 1838 * Callers need to check if skb has a conntrack assigned when this 1839 * helper returns; in such case skb belongs to an already known connection. 1840 */ 1841 static unsigned int __cold 1842 nf_conntrack_handle_icmp(struct nf_conn *tmpl, 1843 struct sk_buff *skb, 1844 unsigned int dataoff, 1845 u8 protonum, 1846 const struct nf_hook_state *state) 1847 { 1848 int ret; 1849 1850 if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP) 1851 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state); 1852 #if IS_ENABLED(CONFIG_IPV6) 1853 else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6) 1854 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state); 1855 #endif 1856 else 1857 return NF_ACCEPT; 1858 1859 if (ret <= 0) 1860 NF_CT_STAT_INC_ATOMIC(state->net, error); 1861 1862 return ret; 1863 } 1864 1865 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb, 1866 enum ip_conntrack_info ctinfo) 1867 { 1868 const unsigned int *timeout = nf_ct_timeout_lookup(ct); 1869 1870 if (!timeout) 1871 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout; 1872 1873 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout); 1874 return NF_ACCEPT; 1875 } 1876 1877 /* Returns verdict for packet, or -1 for invalid. */ 1878 static int nf_conntrack_handle_packet(struct nf_conn *ct, 1879 struct sk_buff *skb, 1880 unsigned int dataoff, 1881 enum ip_conntrack_info ctinfo, 1882 const struct nf_hook_state *state) 1883 { 1884 switch (nf_ct_protonum(ct)) { 1885 case IPPROTO_TCP: 1886 return nf_conntrack_tcp_packet(ct, skb, dataoff, 1887 ctinfo, state); 1888 case IPPROTO_UDP: 1889 return nf_conntrack_udp_packet(ct, skb, dataoff, 1890 ctinfo, state); 1891 case IPPROTO_ICMP: 1892 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state); 1893 #if IS_ENABLED(CONFIG_IPV6) 1894 case IPPROTO_ICMPV6: 1895 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state); 1896 #endif 1897 #ifdef CONFIG_NF_CT_PROTO_UDPLITE 1898 case IPPROTO_UDPLITE: 1899 return nf_conntrack_udplite_packet(ct, skb, dataoff, 1900 ctinfo, state); 1901 #endif 1902 #ifdef CONFIG_NF_CT_PROTO_SCTP 1903 case IPPROTO_SCTP: 1904 return nf_conntrack_sctp_packet(ct, skb, dataoff, 1905 ctinfo, state); 1906 #endif 1907 #ifdef CONFIG_NF_CT_PROTO_DCCP 1908 case IPPROTO_DCCP: 1909 return nf_conntrack_dccp_packet(ct, skb, dataoff, 1910 ctinfo, state); 1911 #endif 1912 #ifdef CONFIG_NF_CT_PROTO_GRE 1913 case IPPROTO_GRE: 1914 return nf_conntrack_gre_packet(ct, skb, dataoff, 1915 ctinfo, state); 1916 #endif 1917 } 1918 1919 return generic_packet(ct, skb, ctinfo); 1920 } 1921 1922 unsigned int 1923 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state) 1924 { 1925 enum ip_conntrack_info ctinfo; 1926 struct nf_conn *ct, *tmpl; 1927 u_int8_t protonum; 1928 int dataoff, ret; 1929 1930 tmpl = nf_ct_get(skb, &ctinfo); 1931 if (tmpl || ctinfo == IP_CT_UNTRACKED) { 1932 /* Previously seen (loopback or untracked)? Ignore. */ 1933 if ((tmpl && !nf_ct_is_template(tmpl)) || 1934 ctinfo == IP_CT_UNTRACKED) 1935 return NF_ACCEPT; 1936 skb->_nfct = 0; 1937 } 1938 1939 /* rcu_read_lock()ed by nf_hook_thresh */ 1940 dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum); 1941 if (dataoff <= 0) { 1942 pr_debug("not prepared to track yet or error occurred\n"); 1943 NF_CT_STAT_INC_ATOMIC(state->net, invalid); 1944 ret = NF_ACCEPT; 1945 goto out; 1946 } 1947 1948 if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) { 1949 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff, 1950 protonum, state); 1951 if (ret <= 0) { 1952 ret = -ret; 1953 goto out; 1954 } 1955 /* ICMP[v6] protocol trackers may assign one conntrack. */ 1956 if (skb->_nfct) 1957 goto out; 1958 } 1959 repeat: 1960 ret = resolve_normal_ct(tmpl, skb, dataoff, 1961 protonum, state); 1962 if (ret < 0) { 1963 /* Too stressed to deal. */ 1964 NF_CT_STAT_INC_ATOMIC(state->net, drop); 1965 ret = NF_DROP; 1966 goto out; 1967 } 1968 1969 ct = nf_ct_get(skb, &ctinfo); 1970 if (!ct) { 1971 /* Not valid part of a connection */ 1972 NF_CT_STAT_INC_ATOMIC(state->net, invalid); 1973 ret = NF_ACCEPT; 1974 goto out; 1975 } 1976 1977 ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state); 1978 if (ret <= 0) { 1979 /* Invalid: inverse of the return code tells 1980 * the netfilter core what to do */ 1981 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 1982 nf_ct_put(ct); 1983 skb->_nfct = 0; 1984 /* Special case: TCP tracker reports an attempt to reopen a 1985 * closed/aborted connection. We have to go back and create a 1986 * fresh conntrack. 1987 */ 1988 if (ret == -NF_REPEAT) 1989 goto repeat; 1990 1991 NF_CT_STAT_INC_ATOMIC(state->net, invalid); 1992 if (ret == -NF_DROP) 1993 NF_CT_STAT_INC_ATOMIC(state->net, drop); 1994 1995 ret = -ret; 1996 goto out; 1997 } 1998 1999 if (ctinfo == IP_CT_ESTABLISHED_REPLY && 2000 !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 2001 nf_conntrack_event_cache(IPCT_REPLY, ct); 2002 out: 2003 if (tmpl) 2004 nf_ct_put(tmpl); 2005 2006 return ret; 2007 } 2008 EXPORT_SYMBOL_GPL(nf_conntrack_in); 2009 2010 /* Alter reply tuple (maybe alter helper). This is for NAT, and is 2011 implicitly racy: see __nf_conntrack_confirm */ 2012 void nf_conntrack_alter_reply(struct nf_conn *ct, 2013 const struct nf_conntrack_tuple *newreply) 2014 { 2015 struct nf_conn_help *help = nfct_help(ct); 2016 2017 /* Should be unconfirmed, so not in hash table yet */ 2018 WARN_ON(nf_ct_is_confirmed(ct)); 2019 2020 pr_debug("Altering reply tuple of %p to ", ct); 2021 nf_ct_dump_tuple(newreply); 2022 2023 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 2024 if (ct->master || (help && !hlist_empty(&help->expectations))) 2025 return; 2026 2027 rcu_read_lock(); 2028 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 2029 rcu_read_unlock(); 2030 } 2031 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 2032 2033 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 2034 void __nf_ct_refresh_acct(struct nf_conn *ct, 2035 enum ip_conntrack_info ctinfo, 2036 const struct sk_buff *skb, 2037 u32 extra_jiffies, 2038 bool do_acct) 2039 { 2040 /* Only update if this is not a fixed timeout */ 2041 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 2042 goto acct; 2043 2044 /* If not in hash table, timer will not be active yet */ 2045 if (nf_ct_is_confirmed(ct)) 2046 extra_jiffies += nfct_time_stamp; 2047 2048 if (READ_ONCE(ct->timeout) != extra_jiffies) 2049 WRITE_ONCE(ct->timeout, extra_jiffies); 2050 acct: 2051 if (do_acct) 2052 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len); 2053 } 2054 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 2055 2056 bool nf_ct_kill_acct(struct nf_conn *ct, 2057 enum ip_conntrack_info ctinfo, 2058 const struct sk_buff *skb) 2059 { 2060 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len); 2061 2062 return nf_ct_delete(ct, 0, 0); 2063 } 2064 EXPORT_SYMBOL_GPL(nf_ct_kill_acct); 2065 2066 #if IS_ENABLED(CONFIG_NF_CT_NETLINK) 2067 2068 #include <linux/netfilter/nfnetlink.h> 2069 #include <linux/netfilter/nfnetlink_conntrack.h> 2070 #include <linux/mutex.h> 2071 2072 /* Generic function for tcp/udp/sctp/dccp and alike. */ 2073 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 2074 const struct nf_conntrack_tuple *tuple) 2075 { 2076 if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) || 2077 nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port)) 2078 goto nla_put_failure; 2079 return 0; 2080 2081 nla_put_failure: 2082 return -1; 2083 } 2084 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 2085 2086 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 2087 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 2088 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 2089 }; 2090 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 2091 2092 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 2093 struct nf_conntrack_tuple *t, 2094 u_int32_t flags) 2095 { 2096 if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) { 2097 if (!tb[CTA_PROTO_SRC_PORT]) 2098 return -EINVAL; 2099 2100 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 2101 } 2102 2103 if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) { 2104 if (!tb[CTA_PROTO_DST_PORT]) 2105 return -EINVAL; 2106 2107 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 2108 } 2109 2110 return 0; 2111 } 2112 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 2113 2114 unsigned int nf_ct_port_nlattr_tuple_size(void) 2115 { 2116 static unsigned int size __read_mostly; 2117 2118 if (!size) 2119 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 2120 2121 return size; 2122 } 2123 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 2124 #endif 2125 2126 /* Used by ipt_REJECT and ip6t_REJECT. */ 2127 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb) 2128 { 2129 struct nf_conn *ct; 2130 enum ip_conntrack_info ctinfo; 2131 2132 /* This ICMP is in reverse direction to the packet which caused it */ 2133 ct = nf_ct_get(skb, &ctinfo); 2134 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 2135 ctinfo = IP_CT_RELATED_REPLY; 2136 else 2137 ctinfo = IP_CT_RELATED; 2138 2139 /* Attach to new skbuff, and increment count */ 2140 nf_ct_set(nskb, ct, ctinfo); 2141 nf_conntrack_get(skb_nfct(nskb)); 2142 } 2143 2144 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb, 2145 struct nf_conn *ct, 2146 enum ip_conntrack_info ctinfo) 2147 { 2148 const struct nf_nat_hook *nat_hook; 2149 struct nf_conntrack_tuple_hash *h; 2150 struct nf_conntrack_tuple tuple; 2151 unsigned int status; 2152 int dataoff; 2153 u16 l3num; 2154 u8 l4num; 2155 2156 l3num = nf_ct_l3num(ct); 2157 2158 dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num); 2159 if (dataoff <= 0) 2160 return -1; 2161 2162 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num, 2163 l4num, net, &tuple)) 2164 return -1; 2165 2166 if (ct->status & IPS_SRC_NAT) { 2167 memcpy(tuple.src.u3.all, 2168 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all, 2169 sizeof(tuple.src.u3.all)); 2170 tuple.src.u.all = 2171 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all; 2172 } 2173 2174 if (ct->status & IPS_DST_NAT) { 2175 memcpy(tuple.dst.u3.all, 2176 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all, 2177 sizeof(tuple.dst.u3.all)); 2178 tuple.dst.u.all = 2179 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all; 2180 } 2181 2182 h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple); 2183 if (!h) 2184 return 0; 2185 2186 /* Store status bits of the conntrack that is clashing to re-do NAT 2187 * mangling according to what it has been done already to this packet. 2188 */ 2189 status = ct->status; 2190 2191 nf_ct_put(ct); 2192 ct = nf_ct_tuplehash_to_ctrack(h); 2193 nf_ct_set(skb, ct, ctinfo); 2194 2195 nat_hook = rcu_dereference(nf_nat_hook); 2196 if (!nat_hook) 2197 return 0; 2198 2199 if (status & IPS_SRC_NAT && 2200 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC, 2201 IP_CT_DIR_ORIGINAL) == NF_DROP) 2202 return -1; 2203 2204 if (status & IPS_DST_NAT && 2205 nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST, 2206 IP_CT_DIR_ORIGINAL) == NF_DROP) 2207 return -1; 2208 2209 return 0; 2210 } 2211 2212 /* This packet is coming from userspace via nf_queue, complete the packet 2213 * processing after the helper invocation in nf_confirm(). 2214 */ 2215 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct, 2216 enum ip_conntrack_info ctinfo) 2217 { 2218 const struct nf_conntrack_helper *helper; 2219 const struct nf_conn_help *help; 2220 int protoff; 2221 2222 help = nfct_help(ct); 2223 if (!help) 2224 return 0; 2225 2226 helper = rcu_dereference(help->helper); 2227 if (!(helper->flags & NF_CT_HELPER_F_USERSPACE)) 2228 return 0; 2229 2230 switch (nf_ct_l3num(ct)) { 2231 case NFPROTO_IPV4: 2232 protoff = skb_network_offset(skb) + ip_hdrlen(skb); 2233 break; 2234 #if IS_ENABLED(CONFIG_IPV6) 2235 case NFPROTO_IPV6: { 2236 __be16 frag_off; 2237 u8 pnum; 2238 2239 pnum = ipv6_hdr(skb)->nexthdr; 2240 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum, 2241 &frag_off); 2242 if (protoff < 0 || (frag_off & htons(~0x7)) != 0) 2243 return 0; 2244 break; 2245 } 2246 #endif 2247 default: 2248 return 0; 2249 } 2250 2251 if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) && 2252 !nf_is_loopback_packet(skb)) { 2253 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) { 2254 NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop); 2255 return -1; 2256 } 2257 } 2258 2259 /* We've seen it coming out the other side: confirm it */ 2260 return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0; 2261 } 2262 2263 static int nf_conntrack_update(struct net *net, struct sk_buff *skb) 2264 { 2265 enum ip_conntrack_info ctinfo; 2266 struct nf_conn *ct; 2267 int err; 2268 2269 ct = nf_ct_get(skb, &ctinfo); 2270 if (!ct) 2271 return 0; 2272 2273 if (!nf_ct_is_confirmed(ct)) { 2274 err = __nf_conntrack_update(net, skb, ct, ctinfo); 2275 if (err < 0) 2276 return err; 2277 2278 ct = nf_ct_get(skb, &ctinfo); 2279 } 2280 2281 return nf_confirm_cthelper(skb, ct, ctinfo); 2282 } 2283 2284 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 2285 const struct sk_buff *skb) 2286 { 2287 const struct nf_conntrack_tuple *src_tuple; 2288 const struct nf_conntrack_tuple_hash *hash; 2289 struct nf_conntrack_tuple srctuple; 2290 enum ip_conntrack_info ctinfo; 2291 struct nf_conn *ct; 2292 2293 ct = nf_ct_get(skb, &ctinfo); 2294 if (ct) { 2295 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo)); 2296 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple)); 2297 return true; 2298 } 2299 2300 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), 2301 NFPROTO_IPV4, dev_net(skb->dev), 2302 &srctuple)) 2303 return false; 2304 2305 hash = nf_conntrack_find_get(dev_net(skb->dev), 2306 &nf_ct_zone_dflt, 2307 &srctuple); 2308 if (!hash) 2309 return false; 2310 2311 ct = nf_ct_tuplehash_to_ctrack(hash); 2312 src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir); 2313 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple)); 2314 nf_ct_put(ct); 2315 2316 return true; 2317 } 2318 2319 /* Bring out ya dead! */ 2320 static struct nf_conn * 2321 get_next_corpse(int (*iter)(struct nf_conn *i, void *data), 2322 void *data, unsigned int *bucket) 2323 { 2324 struct nf_conntrack_tuple_hash *h; 2325 struct nf_conn *ct; 2326 struct hlist_nulls_node *n; 2327 spinlock_t *lockp; 2328 2329 for (; *bucket < nf_conntrack_htable_size; (*bucket)++) { 2330 struct hlist_nulls_head *hslot = &nf_conntrack_hash[*bucket]; 2331 2332 if (hlist_nulls_empty(hslot)) 2333 continue; 2334 2335 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS]; 2336 local_bh_disable(); 2337 nf_conntrack_lock(lockp); 2338 hlist_nulls_for_each_entry(h, n, hslot, hnnode) { 2339 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY) 2340 continue; 2341 /* All nf_conn objects are added to hash table twice, one 2342 * for original direction tuple, once for the reply tuple. 2343 * 2344 * Exception: In the IPS_NAT_CLASH case, only the reply 2345 * tuple is added (the original tuple already existed for 2346 * a different object). 2347 * 2348 * We only need to call the iterator once for each 2349 * conntrack, so we just use the 'reply' direction 2350 * tuple while iterating. 2351 */ 2352 ct = nf_ct_tuplehash_to_ctrack(h); 2353 if (iter(ct, data)) 2354 goto found; 2355 } 2356 spin_unlock(lockp); 2357 local_bh_enable(); 2358 cond_resched(); 2359 } 2360 2361 return NULL; 2362 found: 2363 refcount_inc(&ct->ct_general.use); 2364 spin_unlock(lockp); 2365 local_bh_enable(); 2366 return ct; 2367 } 2368 2369 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data), 2370 void *data, u32 portid, int report) 2371 { 2372 unsigned int bucket = 0; 2373 struct nf_conn *ct; 2374 2375 might_sleep(); 2376 2377 mutex_lock(&nf_conntrack_mutex); 2378 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) { 2379 /* Time to push up daises... */ 2380 2381 nf_ct_delete(ct, portid, report); 2382 nf_ct_put(ct); 2383 cond_resched(); 2384 } 2385 mutex_unlock(&nf_conntrack_mutex); 2386 } 2387 2388 struct iter_data { 2389 int (*iter)(struct nf_conn *i, void *data); 2390 void *data; 2391 struct net *net; 2392 }; 2393 2394 static int iter_net_only(struct nf_conn *i, void *data) 2395 { 2396 struct iter_data *d = data; 2397 2398 if (!net_eq(d->net, nf_ct_net(i))) 2399 return 0; 2400 2401 return d->iter(i, d->data); 2402 } 2403 2404 static void 2405 __nf_ct_unconfirmed_destroy(struct net *net) 2406 { 2407 int cpu; 2408 2409 for_each_possible_cpu(cpu) { 2410 struct nf_conntrack_tuple_hash *h; 2411 struct hlist_nulls_node *n; 2412 struct ct_pcpu *pcpu; 2413 2414 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); 2415 2416 spin_lock_bh(&pcpu->lock); 2417 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) { 2418 struct nf_conn *ct; 2419 2420 ct = nf_ct_tuplehash_to_ctrack(h); 2421 2422 /* we cannot call iter() on unconfirmed list, the 2423 * owning cpu can reallocate ct->ext at any time. 2424 */ 2425 set_bit(IPS_DYING_BIT, &ct->status); 2426 } 2427 spin_unlock_bh(&pcpu->lock); 2428 cond_resched(); 2429 } 2430 } 2431 2432 void nf_ct_unconfirmed_destroy(struct net *net) 2433 { 2434 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2435 2436 might_sleep(); 2437 2438 if (atomic_read(&cnet->count) > 0) { 2439 __nf_ct_unconfirmed_destroy(net); 2440 nf_queue_nf_hook_drop(net); 2441 synchronize_net(); 2442 } 2443 } 2444 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy); 2445 2446 void nf_ct_iterate_cleanup_net(struct net *net, 2447 int (*iter)(struct nf_conn *i, void *data), 2448 void *data, u32 portid, int report) 2449 { 2450 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2451 struct iter_data d; 2452 2453 might_sleep(); 2454 2455 if (atomic_read(&cnet->count) == 0) 2456 return; 2457 2458 d.iter = iter; 2459 d.data = data; 2460 d.net = net; 2461 2462 nf_ct_iterate_cleanup(iter_net_only, &d, portid, report); 2463 } 2464 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net); 2465 2466 /** 2467 * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table 2468 * @iter: callback to invoke for each conntrack 2469 * @data: data to pass to @iter 2470 * 2471 * Like nf_ct_iterate_cleanup, but first marks conntracks on the 2472 * unconfirmed list as dying (so they will not be inserted into 2473 * main table). 2474 * 2475 * Can only be called in module exit path. 2476 */ 2477 void 2478 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data) 2479 { 2480 struct net *net; 2481 2482 down_read(&net_rwsem); 2483 for_each_net(net) { 2484 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2485 2486 if (atomic_read(&cnet->count) == 0) 2487 continue; 2488 __nf_ct_unconfirmed_destroy(net); 2489 nf_queue_nf_hook_drop(net); 2490 } 2491 up_read(&net_rwsem); 2492 2493 /* Need to wait for netns cleanup worker to finish, if its 2494 * running -- it might have deleted a net namespace from 2495 * the global list, so our __nf_ct_unconfirmed_destroy() might 2496 * not have affected all namespaces. 2497 */ 2498 net_ns_barrier(); 2499 2500 /* a conntrack could have been unlinked from unconfirmed list 2501 * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy(). 2502 * This makes sure its inserted into conntrack table. 2503 */ 2504 synchronize_net(); 2505 2506 nf_ct_iterate_cleanup(iter, data, 0, 0); 2507 } 2508 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy); 2509 2510 static int kill_all(struct nf_conn *i, void *data) 2511 { 2512 return net_eq(nf_ct_net(i), data); 2513 } 2514 2515 void nf_conntrack_cleanup_start(void) 2516 { 2517 conntrack_gc_work.exiting = true; 2518 } 2519 2520 void nf_conntrack_cleanup_end(void) 2521 { 2522 RCU_INIT_POINTER(nf_ct_hook, NULL); 2523 cancel_delayed_work_sync(&conntrack_gc_work.dwork); 2524 kvfree(nf_conntrack_hash); 2525 2526 nf_conntrack_proto_fini(); 2527 nf_conntrack_helper_fini(); 2528 nf_conntrack_expect_fini(); 2529 2530 kmem_cache_destroy(nf_conntrack_cachep); 2531 } 2532 2533 /* 2534 * Mishearing the voices in his head, our hero wonders how he's 2535 * supposed to kill the mall. 2536 */ 2537 void nf_conntrack_cleanup_net(struct net *net) 2538 { 2539 LIST_HEAD(single); 2540 2541 list_add(&net->exit_list, &single); 2542 nf_conntrack_cleanup_net_list(&single); 2543 } 2544 2545 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list) 2546 { 2547 int busy; 2548 struct net *net; 2549 2550 /* 2551 * This makes sure all current packets have passed through 2552 * netfilter framework. Roll on, two-stage module 2553 * delete... 2554 */ 2555 synchronize_net(); 2556 i_see_dead_people: 2557 busy = 0; 2558 list_for_each_entry(net, net_exit_list, exit_list) { 2559 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2560 2561 nf_ct_iterate_cleanup(kill_all, net, 0, 0); 2562 if (atomic_read(&cnet->count) != 0) 2563 busy = 1; 2564 } 2565 if (busy) { 2566 schedule(); 2567 goto i_see_dead_people; 2568 } 2569 2570 list_for_each_entry(net, net_exit_list, exit_list) { 2571 nf_conntrack_ecache_pernet_fini(net); 2572 nf_conntrack_expect_pernet_fini(net); 2573 free_percpu(net->ct.stat); 2574 free_percpu(net->ct.pcpu_lists); 2575 } 2576 } 2577 2578 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls) 2579 { 2580 struct hlist_nulls_head *hash; 2581 unsigned int nr_slots, i; 2582 2583 if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head))) 2584 return NULL; 2585 2586 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 2587 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 2588 2589 hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL); 2590 2591 if (hash && nulls) 2592 for (i = 0; i < nr_slots; i++) 2593 INIT_HLIST_NULLS_HEAD(&hash[i], i); 2594 2595 return hash; 2596 } 2597 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 2598 2599 int nf_conntrack_hash_resize(unsigned int hashsize) 2600 { 2601 int i, bucket; 2602 unsigned int old_size; 2603 struct hlist_nulls_head *hash, *old_hash; 2604 struct nf_conntrack_tuple_hash *h; 2605 struct nf_conn *ct; 2606 2607 if (!hashsize) 2608 return -EINVAL; 2609 2610 hash = nf_ct_alloc_hashtable(&hashsize, 1); 2611 if (!hash) 2612 return -ENOMEM; 2613 2614 mutex_lock(&nf_conntrack_mutex); 2615 old_size = nf_conntrack_htable_size; 2616 if (old_size == hashsize) { 2617 mutex_unlock(&nf_conntrack_mutex); 2618 kvfree(hash); 2619 return 0; 2620 } 2621 2622 local_bh_disable(); 2623 nf_conntrack_all_lock(); 2624 write_seqcount_begin(&nf_conntrack_generation); 2625 2626 /* Lookups in the old hash might happen in parallel, which means we 2627 * might get false negatives during connection lookup. New connections 2628 * created because of a false negative won't make it into the hash 2629 * though since that required taking the locks. 2630 */ 2631 2632 for (i = 0; i < nf_conntrack_htable_size; i++) { 2633 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) { 2634 unsigned int zone_id; 2635 2636 h = hlist_nulls_entry(nf_conntrack_hash[i].first, 2637 struct nf_conntrack_tuple_hash, hnnode); 2638 ct = nf_ct_tuplehash_to_ctrack(h); 2639 hlist_nulls_del_rcu(&h->hnnode); 2640 2641 zone_id = nf_ct_zone_id(nf_ct_zone(ct), NF_CT_DIRECTION(h)); 2642 bucket = __hash_conntrack(nf_ct_net(ct), 2643 &h->tuple, zone_id, hashsize); 2644 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 2645 } 2646 } 2647 old_hash = nf_conntrack_hash; 2648 2649 nf_conntrack_hash = hash; 2650 nf_conntrack_htable_size = hashsize; 2651 2652 write_seqcount_end(&nf_conntrack_generation); 2653 nf_conntrack_all_unlock(); 2654 local_bh_enable(); 2655 2656 mutex_unlock(&nf_conntrack_mutex); 2657 2658 synchronize_net(); 2659 kvfree(old_hash); 2660 return 0; 2661 } 2662 2663 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp) 2664 { 2665 unsigned int hashsize; 2666 int rc; 2667 2668 if (current->nsproxy->net_ns != &init_net) 2669 return -EOPNOTSUPP; 2670 2671 /* On boot, we can set this without any fancy locking. */ 2672 if (!nf_conntrack_hash) 2673 return param_set_uint(val, kp); 2674 2675 rc = kstrtouint(val, 0, &hashsize); 2676 if (rc) 2677 return rc; 2678 2679 return nf_conntrack_hash_resize(hashsize); 2680 } 2681 2682 int nf_conntrack_init_start(void) 2683 { 2684 unsigned long nr_pages = totalram_pages(); 2685 int max_factor = 8; 2686 int ret = -ENOMEM; 2687 int i; 2688 2689 seqcount_spinlock_init(&nf_conntrack_generation, 2690 &nf_conntrack_locks_all_lock); 2691 2692 for (i = 0; i < CONNTRACK_LOCKS; i++) 2693 spin_lock_init(&nf_conntrack_locks[i]); 2694 2695 if (!nf_conntrack_htable_size) { 2696 nf_conntrack_htable_size 2697 = (((nr_pages << PAGE_SHIFT) / 16384) 2698 / sizeof(struct hlist_head)); 2699 if (BITS_PER_LONG >= 64 && 2700 nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE))) 2701 nf_conntrack_htable_size = 262144; 2702 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 2703 nf_conntrack_htable_size = 65536; 2704 2705 if (nf_conntrack_htable_size < 1024) 2706 nf_conntrack_htable_size = 1024; 2707 /* Use a max. factor of one by default to keep the average 2708 * hash chain length at 2 entries. Each entry has to be added 2709 * twice (once for original direction, once for reply). 2710 * When a table size is given we use the old value of 8 to 2711 * avoid implicit reduction of the max entries setting. 2712 */ 2713 max_factor = 1; 2714 } 2715 2716 nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1); 2717 if (!nf_conntrack_hash) 2718 return -ENOMEM; 2719 2720 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 2721 2722 nf_conntrack_cachep = kmem_cache_create("nf_conntrack", 2723 sizeof(struct nf_conn), 2724 NFCT_INFOMASK + 1, 2725 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL); 2726 if (!nf_conntrack_cachep) 2727 goto err_cachep; 2728 2729 ret = nf_conntrack_expect_init(); 2730 if (ret < 0) 2731 goto err_expect; 2732 2733 ret = nf_conntrack_helper_init(); 2734 if (ret < 0) 2735 goto err_helper; 2736 2737 ret = nf_conntrack_proto_init(); 2738 if (ret < 0) 2739 goto err_proto; 2740 2741 conntrack_gc_work_init(&conntrack_gc_work); 2742 queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ); 2743 2744 ret = register_nf_conntrack_bpf(); 2745 if (ret < 0) 2746 goto err_kfunc; 2747 2748 return 0; 2749 2750 err_kfunc: 2751 cancel_delayed_work_sync(&conntrack_gc_work.dwork); 2752 nf_conntrack_proto_fini(); 2753 err_proto: 2754 nf_conntrack_helper_fini(); 2755 err_helper: 2756 nf_conntrack_expect_fini(); 2757 err_expect: 2758 kmem_cache_destroy(nf_conntrack_cachep); 2759 err_cachep: 2760 kvfree(nf_conntrack_hash); 2761 return ret; 2762 } 2763 2764 static const struct nf_ct_hook nf_conntrack_hook = { 2765 .update = nf_conntrack_update, 2766 .destroy = nf_ct_destroy, 2767 .get_tuple_skb = nf_conntrack_get_tuple_skb, 2768 .attach = nf_conntrack_attach, 2769 }; 2770 2771 void nf_conntrack_init_end(void) 2772 { 2773 RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook); 2774 } 2775 2776 /* 2777 * We need to use special "null" values, not used in hash table 2778 */ 2779 #define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 2780 #define DYING_NULLS_VAL ((1<<30)+1) 2781 2782 int nf_conntrack_init_net(struct net *net) 2783 { 2784 struct nf_conntrack_net *cnet = nf_ct_pernet(net); 2785 int ret = -ENOMEM; 2786 int cpu; 2787 2788 BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER); 2789 BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS); 2790 atomic_set(&cnet->count, 0); 2791 2792 net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu); 2793 if (!net->ct.pcpu_lists) 2794 goto err_stat; 2795 2796 for_each_possible_cpu(cpu) { 2797 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu); 2798 2799 spin_lock_init(&pcpu->lock); 2800 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL); 2801 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL); 2802 } 2803 2804 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 2805 if (!net->ct.stat) 2806 goto err_pcpu_lists; 2807 2808 ret = nf_conntrack_expect_pernet_init(net); 2809 if (ret < 0) 2810 goto err_expect; 2811 2812 nf_conntrack_acct_pernet_init(net); 2813 nf_conntrack_tstamp_pernet_init(net); 2814 nf_conntrack_ecache_pernet_init(net); 2815 nf_conntrack_helper_pernet_init(net); 2816 nf_conntrack_proto_pernet_init(net); 2817 2818 return 0; 2819 2820 err_expect: 2821 free_percpu(net->ct.stat); 2822 err_pcpu_lists: 2823 free_percpu(net->ct.pcpu_lists); 2824 err_stat: 2825 return ret; 2826 } 2827