net/netfilter/nf_conntrack_core.c

   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                     count;
  71         u32                     start_time;
  72         bool                    exiting;
  73         bool                    early_drop;
  74 };
  75
  76 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
  77 static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
  78 static __read_mostly bool nf_conntrack_locks_all;
  79
  80 /* serialize hash resizes and nf_ct_iterate_cleanup */
  81 static DEFINE_MUTEX(nf_conntrack_mutex);
  82
  83 #define GC_SCAN_INTERVAL_MAX    (60ul * HZ)
  84 #define GC_SCAN_INTERVAL_MIN    (1ul * HZ)
  85
  86 /* clamp timeouts to this value (TCP unacked) */
  87 #define GC_SCAN_INTERVAL_CLAMP  (300ul * HZ)
  88
  89 /* Initial bias pretending we have 100 entries at the upper bound so we don't
  90  * wakeup often just because we have three entries with a 1s timeout while still
  91  * allowing non-idle machines to wakeup more often when needed.
  92  */
  93 #define GC_SCAN_INITIAL_COUNT   100
  94 #define GC_SCAN_INTERVAL_INIT   GC_SCAN_INTERVAL_MAX
  95
  96 #define GC_SCAN_MAX_DURATION    msecs_to_jiffies(10)
  97 #define GC_SCAN_EXPIRED_MAX     (64000u / HZ)
  98
  99 #define MIN_CHAINLEN    50u
 100 #define MAX_CHAINLEN    (80u - MIN_CHAINLEN)
 101
 102 static struct conntrack_gc_work conntrack_gc_work;
 103
 104 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
 105 {
 106         /* 1) Acquire the lock */
 107         spin_lock(lock);
 108
 109         /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
 110          * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
 111          */
 112         if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
 113                 return;
 114
 115         /* fast path failed, unlock */
 116         spin_unlock(lock);
 117
 118         /* Slow path 1) get global lock */
 119         spin_lock(&nf_conntrack_locks_all_lock);
 120
 121         /* Slow path 2) get the lock we want */
 122         spin_lock(lock);
 123
 124         /* Slow path 3) release the global lock */
 125         spin_unlock(&nf_conntrack_locks_all_lock);
 126 }
 127 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
 128
 129 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
 130 {
 131         h1 %= CONNTRACK_LOCKS;
 132         h2 %= CONNTRACK_LOCKS;
 133         spin_unlock(&nf_conntrack_locks[h1]);
 134         if (h1 != h2)
 135                 spin_unlock(&nf_conntrack_locks[h2]);
 136 }
 137
 138 /* return true if we need to recompute hashes (in case hash table was resized) */
 139 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
 140                                      unsigned int h2, unsigned int sequence)
 141 {
 142         h1 %= CONNTRACK_LOCKS;
 143         h2 %= CONNTRACK_LOCKS;
 144         if (h1 <= h2) {
 145                 nf_conntrack_lock(&nf_conntrack_locks[h1]);
 146                 if (h1 != h2)
 147                         spin_lock_nested(&nf_conntrack_locks[h2],
 148                                          SINGLE_DEPTH_NESTING);
 149         } else {
 150                 nf_conntrack_lock(&nf_conntrack_locks[h2]);
 151                 spin_lock_nested(&nf_conntrack_locks[h1],
 152                                  SINGLE_DEPTH_NESTING);
 153         }
 154         if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
 155                 nf_conntrack_double_unlock(h1, h2);
 156                 return true;
 157         }
 158         return false;
 159 }
 160
 161 static void nf_conntrack_all_lock(void)
 162         __acquires(&nf_conntrack_locks_all_lock)
 163 {
 164         int i;
 165
 166         spin_lock(&nf_conntrack_locks_all_lock);
 167
 168         /* For nf_contrack_locks_all, only the latest time when another
 169          * CPU will see an update is controlled, by the "release" of the
 170          * spin_lock below.
 171          * The earliest time is not controlled, an thus KCSAN could detect
 172          * a race when nf_conntract_lock() reads the variable.
 173          * WRITE_ONCE() is used to ensure the compiler will not
 174          * optimize the write.
 175          */
 176         WRITE_ONCE(nf_conntrack_locks_all, true);
 177
 178         for (i = 0; i < CONNTRACK_LOCKS; i++) {
 179                 spin_lock(&nf_conntrack_locks[i]);
 180
 181                 /* This spin_unlock provides the "release" to ensure that
 182                  * nf_conntrack_locks_all==true is visible to everyone that
 183                  * acquired spin_lock(&nf_conntrack_locks[]).
 184                  */
 185                 spin_unlock(&nf_conntrack_locks[i]);
 186         }
 187 }
 188
 189 static void nf_conntrack_all_unlock(void)
 190         __releases(&nf_conntrack_locks_all_lock)
 191 {
 192         /* All prior stores must be complete before we clear
 193          * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
 194          * might observe the false value but not the entire
 195          * critical section.
 196          * It pairs with the smp_load_acquire() in nf_conntrack_lock()
 197          */
 198         smp_store_release(&nf_conntrack_locks_all, false);
 199         spin_unlock(&nf_conntrack_locks_all_lock);
 200 }
 201
 202 unsigned int nf_conntrack_htable_size __read_mostly;
 203 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
 204
 205 unsigned int nf_conntrack_max __read_mostly;
 206 EXPORT_SYMBOL_GPL(nf_conntrack_max);
 207 seqcount_spinlock_t nf_conntrack_generation __read_mostly;
 208 static siphash_aligned_key_t nf_conntrack_hash_rnd;
 209
 210 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
 211                               unsigned int zoneid,
 212                               const struct net *net)
 213 {
 214         struct {
 215                 struct nf_conntrack_man src;
 216                 union nf_inet_addr dst_addr;
 217                 unsigned int zone;
 218                 u32 net_mix;
 219                 u16 dport;
 220                 u16 proto;
 221         } __aligned(SIPHASH_ALIGNMENT) combined;
 222
 223         get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
 224
 225         memset(&combined, 0, sizeof(combined));
 226
 227         /* The direction must be ignored, so handle usable members manually. */
 228         combined.src = tuple->src;
 229         combined.dst_addr = tuple->dst.u3;
 230         combined.zone = zoneid;
 231         combined.net_mix = net_hash_mix(net);
 232         combined.dport = (__force __u16)tuple->dst.u.all;
 233         combined.proto = tuple->dst.protonum;
 234
 235         return (u32)siphash(&combined, sizeof(combined), &nf_conntrack_hash_rnd);
 236 }
 237
 238 static u32 scale_hash(u32 hash)
 239 {
 240         return reciprocal_scale(hash, nf_conntrack_htable_size);
 241 }
 242
 243 static u32 __hash_conntrack(const struct net *net,
 244                             const struct nf_conntrack_tuple *tuple,
 245                             unsigned int zoneid,
 246                             unsigned int size)
 247 {
 248         return reciprocal_scale(hash_conntrack_raw(tuple, zoneid, net), size);
 249 }
 250
 251 static u32 hash_conntrack(const struct net *net,
 252                           const struct nf_conntrack_tuple *tuple,
 253                           unsigned int zoneid)
 254 {
 255         return scale_hash(hash_conntrack_raw(tuple, zoneid, net));
 256 }
 257
 258 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
 259                                   unsigned int dataoff,
 260                                   struct nf_conntrack_tuple *tuple)
 261 {       struct {
 262                 __be16 sport;
 263                 __be16 dport;
 264         } _inet_hdr, *inet_hdr;
 265
 266         /* Actually only need first 4 bytes to get ports. */
 267         inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
 268         if (!inet_hdr)
 269                 return false;
 270
 271         tuple->src.u.udp.port = inet_hdr->sport;
 272         tuple->dst.u.udp.port = inet_hdr->dport;
 273         return true;
 274 }
 275
 276 static bool
 277 nf_ct_get_tuple(const struct sk_buff *skb,
 278                 unsigned int nhoff,
 279                 unsigned int dataoff,
 280                 u_int16_t l3num,
 281                 u_int8_t protonum,
 282                 struct net *net,
 283                 struct nf_conntrack_tuple *tuple)
 284 {
 285         unsigned int size;
 286         const __be32 *ap;
 287         __be32 _addrs[8];
 288
 289         memset(tuple, 0, sizeof(*tuple));
 290
 291         tuple->src.l3num = l3num;
 292         switch (l3num) {
 293         case NFPROTO_IPV4:
 294                 nhoff += offsetof(struct iphdr, saddr);
 295                 size = 2 * sizeof(__be32);
 296                 break;
 297         case NFPROTO_IPV6:
 298                 nhoff += offsetof(struct ipv6hdr, saddr);
 299                 size = sizeof(_addrs);
 300                 break;
 301         default:
 302                 return true;
 303         }
 304
 305         ap = skb_header_pointer(skb, nhoff, size, _addrs);
 306         if (!ap)
 307                 return false;
 308
 309         switch (l3num) {
 310         case NFPROTO_IPV4:
 311                 tuple->src.u3.ip = ap[0];
 312                 tuple->dst.u3.ip = ap[1];
 313                 break;
 314         case NFPROTO_IPV6:
 315                 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
 316                 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
 317                 break;
 318         }
 319
 320         tuple->dst.protonum = protonum;
 321         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 322
 323         switch (protonum) {
 324 #if IS_ENABLED(CONFIG_IPV6)
 325         case IPPROTO_ICMPV6:
 326                 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
 327 #endif
 328         case IPPROTO_ICMP:
 329                 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
 330 #ifdef CONFIG_NF_CT_PROTO_GRE
 331         case IPPROTO_GRE:
 332                 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
 333 #endif
 334         case IPPROTO_TCP:
 335         case IPPROTO_UDP:
 336 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
 337         case IPPROTO_UDPLITE:
 338 #endif
 339 #ifdef CONFIG_NF_CT_PROTO_SCTP
 340         case IPPROTO_SCTP:
 341 #endif
 342 #ifdef CONFIG_NF_CT_PROTO_DCCP
 343         case IPPROTO_DCCP:
 344 #endif
 345                 /* fallthrough */
 346                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 347         default:
 348                 break;
 349         }
 350
 351         return true;
 352 }
 353
 354 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 355                             u_int8_t *protonum)
 356 {
 357         int dataoff = -1;
 358         const struct iphdr *iph;
 359         struct iphdr _iph;
 360
 361         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
 362         if (!iph)
 363                 return -1;
 364
 365         /* Conntrack defragments packets, we might still see fragments
 366          * inside ICMP packets though.
 367          */
 368         if (iph->frag_off & htons(IP_OFFSET))
 369                 return -1;
 370
 371         dataoff = nhoff + (iph->ihl << 2);
 372         *protonum = iph->protocol;
 373
 374         /* Check bogus IP headers */
 375         if (dataoff > skb->len) {
 376                 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
 377                          nhoff, iph->ihl << 2, skb->len);
 378                 return -1;
 379         }
 380         return dataoff;
 381 }
 382
 383 #if IS_ENABLED(CONFIG_IPV6)
 384 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 385                             u8 *protonum)
 386 {
 387         int protoff = -1;
 388         unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
 389         __be16 frag_off;
 390         u8 nexthdr;
 391
 392         if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
 393                           &nexthdr, sizeof(nexthdr)) != 0) {
 394                 pr_debug("can't get nexthdr\n");
 395                 return -1;
 396         }
 397         protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
 398         /*
 399          * (protoff == skb->len) means the packet has not data, just
 400          * IPv6 and possibly extensions headers, but it is tracked anyway
 401          */
 402         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 403                 pr_debug("can't find proto in pkt\n");
 404                 return -1;
 405         }
 406
 407         *protonum = nexthdr;
 408         return protoff;
 409 }
 410 #endif
 411
 412 static int get_l4proto(const struct sk_buff *skb,
 413                        unsigned int nhoff, u8 pf, u8 *l4num)
 414 {
 415         switch (pf) {
 416         case NFPROTO_IPV4:
 417                 return ipv4_get_l4proto(skb, nhoff, l4num);
 418 #if IS_ENABLED(CONFIG_IPV6)
 419         case NFPROTO_IPV6:
 420                 return ipv6_get_l4proto(skb, nhoff, l4num);
 421 #endif
 422         default:
 423                 *l4num = 0;
 424                 break;
 425         }
 426         return -1;
 427 }
 428
 429 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 430                        u_int16_t l3num,
 431                        struct net *net, struct nf_conntrack_tuple *tuple)
 432 {
 433         u8 protonum;
 434         int protoff;
 435
 436         protoff = get_l4proto(skb, nhoff, l3num, &protonum);
 437         if (protoff <= 0)
 438                 return false;
 439
 440         return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
 441 }
 442 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 443
 444 bool
 445 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 446                    const struct nf_conntrack_tuple *orig)
 447 {
 448         memset(inverse, 0, sizeof(*inverse));
 449
 450         inverse->src.l3num = orig->src.l3num;
 451
 452         switch (orig->src.l3num) {
 453         case NFPROTO_IPV4:
 454                 inverse->src.u3.ip = orig->dst.u3.ip;
 455                 inverse->dst.u3.ip = orig->src.u3.ip;
 456                 break;
 457         case NFPROTO_IPV6:
 458                 inverse->src.u3.in6 = orig->dst.u3.in6;
 459                 inverse->dst.u3.in6 = orig->src.u3.in6;
 460                 break;
 461         default:
 462                 break;
 463         }
 464
 465         inverse->dst.dir = !orig->dst.dir;
 466
 467         inverse->dst.protonum = orig->dst.protonum;
 468
 469         switch (orig->dst.protonum) {
 470         case IPPROTO_ICMP:
 471                 return nf_conntrack_invert_icmp_tuple(inverse, orig);
 472 #if IS_ENABLED(CONFIG_IPV6)
 473         case IPPROTO_ICMPV6:
 474                 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
 475 #endif
 476         }
 477
 478         inverse->src.u.all = orig->dst.u.all;
 479         inverse->dst.u.all = orig->src.u.all;
 480         return true;
 481 }
 482 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 483
 484 /* Generate a almost-unique pseudo-id for a given conntrack.
 485  *
 486  * intentionally doesn't re-use any of the seeds used for hash
 487  * table location, we assume id gets exposed to userspace.
 488  *
 489  * Following nf_conn items do not change throughout lifetime
 490  * of the nf_conn:
 491  *
 492  * 1. nf_conn address
 493  * 2. nf_conn->master address (normally NULL)
 494  * 3. the associated net namespace
 495  * 4. the original direction tuple
 496  */
 497 u32 nf_ct_get_id(const struct nf_conn *ct)
 498 {
 499         static siphash_aligned_key_t ct_id_seed;
 500         unsigned long a, b, c, d;
 501
 502         net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
 503
 504         a = (unsigned long)ct;
 505         b = (unsigned long)ct->master;
 506         c = (unsigned long)nf_ct_net(ct);
 507         d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 508                                    sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
 509                                    &ct_id_seed);
 510 #ifdef CONFIG_64BIT
 511         return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
 512 #else
 513         return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
 514 #endif
 515 }
 516 EXPORT_SYMBOL_GPL(nf_ct_get_id);
 517
 518 static void
 519 clean_from_lists(struct nf_conn *ct)
 520 {
 521         pr_debug("clean_from_lists(%p)\n", ct);
 522         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 523         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 524
 525         /* Destroy all pending expectations */
 526         nf_ct_remove_expectations(ct);
 527 }
 528
 529 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
 530
 531 /* Released via nf_ct_destroy() */
 532 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 533                                  const struct nf_conntrack_zone *zone,
 534                                  gfp_t flags)
 535 {
 536         struct nf_conn *tmpl, *p;
 537
 538         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
 539                 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
 540                 if (!tmpl)
 541                         return NULL;
 542
 543                 p = tmpl;
 544                 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 545                 if (tmpl != p) {
 546                         tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 547                         tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
 548                 }
 549         } else {
 550                 tmpl = kzalloc(sizeof(*tmpl), flags);
 551                 if (!tmpl)
 552                         return NULL;
 553         }
 554
 555         tmpl->status = IPS_TEMPLATE;
 556         write_pnet(&tmpl->ct_net, net);
 557         nf_ct_zone_add(tmpl, zone);
 558         refcount_set(&tmpl->ct_general.use, 1);
 559
 560         return tmpl;
 561 }
 562 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
 563
 564 void nf_ct_tmpl_free(struct nf_conn *tmpl)
 565 {
 566         kfree(tmpl->ext);
 567
 568         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
 569                 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
 570         else
 571                 kfree(tmpl);
 572 }
 573 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
 574
 575 static void destroy_gre_conntrack(struct nf_conn *ct)
 576 {
 577 #ifdef CONFIG_NF_CT_PROTO_GRE
 578         struct nf_conn *master = ct->master;
 579
 580         if (master)
 581                 nf_ct_gre_keymap_destroy(master);
 582 #endif
 583 }
 584
 585 void nf_ct_destroy(struct nf_conntrack *nfct)
 586 {
 587         struct nf_conn *ct = (struct nf_conn *)nfct;
 588
 589         pr_debug("%s(%p)\n", __func__, ct);
 590         WARN_ON(refcount_read(&nfct->use) != 0);
 591
 592         if (unlikely(nf_ct_is_template(ct))) {
 593                 nf_ct_tmpl_free(ct);
 594                 return;
 595         }
 596
 597         if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
 598                 destroy_gre_conntrack(ct);
 599
 600         /* Expectations will have been removed in clean_from_lists,
 601          * except TFTP can create an expectation on the first packet,
 602          * before connection is in the list, so we need to clean here,
 603          * too.
 604          */
 605         nf_ct_remove_expectations(ct);
 606
 607         if (ct->master)
 608                 nf_ct_put(ct->master);
 609
 610         pr_debug("%s: returning ct=%p to slab\n", __func__, ct);
 611         nf_conntrack_free(ct);
 612 }
 613 EXPORT_SYMBOL(nf_ct_destroy);
 614
 615 static void __nf_ct_delete_from_lists(struct nf_conn *ct)
 616 {
 617         struct net *net = nf_ct_net(ct);
 618         unsigned int hash, reply_hash;
 619         unsigned int sequence;
 620
 621         do {
 622                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 623                 hash = hash_conntrack(net,
 624                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 625                                       nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL));
 626                 reply_hash = hash_conntrack(net,
 627                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 628                                            nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
 629         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 630
 631         clean_from_lists(ct);
 632         nf_conntrack_double_unlock(hash, reply_hash);
 633 }
 634
 635 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 636 {
 637         nf_ct_helper_destroy(ct);
 638         local_bh_disable();
 639
 640         __nf_ct_delete_from_lists(ct);
 641
 642         local_bh_enable();
 643 }
 644
 645 static void nf_ct_add_to_ecache_list(struct nf_conn *ct)
 646 {
 647 #ifdef CONFIG_NF_CONNTRACK_EVENTS
 648         struct nf_conntrack_net *cnet = nf_ct_pernet(nf_ct_net(ct));
 649
 650         spin_lock(&cnet->ecache.dying_lock);
 651         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 652                                  &cnet->ecache.dying_list);
 653         spin_unlock(&cnet->ecache.dying_lock);
 654 #endif
 655 }
 656
 657 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 658 {
 659         struct nf_conn_tstamp *tstamp;
 660         struct net *net;
 661
 662         if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
 663                 return false;
 664
 665         tstamp = nf_conn_tstamp_find(ct);
 666         if (tstamp) {
 667                 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
 668
 669                 tstamp->stop = ktime_get_real_ns();
 670                 if (timeout < 0)
 671                         tstamp->stop -= jiffies_to_nsecs(-timeout);
 672         }
 673
 674         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 675                                     portid, report) < 0) {
 676                 /* destroy event was not delivered. nf_ct_put will
 677                  * be done by event cache worker on redelivery.
 678                  */
 679                 nf_ct_helper_destroy(ct);
 680                 local_bh_disable();
 681                 __nf_ct_delete_from_lists(ct);
 682                 nf_ct_add_to_ecache_list(ct);
 683                 local_bh_enable();
 684
 685                 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL);
 686                 return false;
 687         }
 688
 689         net = nf_ct_net(ct);
 690         if (nf_conntrack_ecache_dwork_pending(net))
 691                 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT);
 692         nf_ct_delete_from_lists(ct);
 693         nf_ct_put(ct);
 694         return true;
 695 }
 696 EXPORT_SYMBOL_GPL(nf_ct_delete);
 697
 698 static inline bool
 699 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 700                 const struct nf_conntrack_tuple *tuple,
 701                 const struct nf_conntrack_zone *zone,
 702                 const struct net *net)
 703 {
 704         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 705
 706         /* A conntrack can be recreated with the equal tuple,
 707          * so we need to check that the conntrack is confirmed
 708          */
 709         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 710                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 711                nf_ct_is_confirmed(ct) &&
 712                net_eq(net, nf_ct_net(ct));
 713 }
 714
 715 static inline bool
 716 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
 717 {
 718         return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 719                                  &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
 720                nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
 721                                  &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
 722                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
 723                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
 724                net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
 725 }
 726
 727 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
 728 static void nf_ct_gc_expired(struct nf_conn *ct)
 729 {
 730         if (!refcount_inc_not_zero(&ct->ct_general.use))
 731                 return;
 732
 733         /* load ->status after refcount increase */
 734         smp_acquire__after_ctrl_dep();
 735
 736         if (nf_ct_should_gc(ct))
 737                 nf_ct_kill(ct);
 738
 739         nf_ct_put(ct);
 740 }
 741
 742 /*
 743  * Warning :
 744  * - Caller must take a reference on returned object
 745  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 746  */
 747 static struct nf_conntrack_tuple_hash *
 748 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 749                       const struct nf_conntrack_tuple *tuple, u32 hash)
 750 {
 751         struct nf_conntrack_tuple_hash *h;
 752         struct hlist_nulls_head *ct_hash;
 753         struct hlist_nulls_node *n;
 754         unsigned int bucket, hsize;
 755
 756 begin:
 757         nf_conntrack_get_ht(&ct_hash, &hsize);
 758         bucket = reciprocal_scale(hash, hsize);
 759
 760         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
 761                 struct nf_conn *ct;
 762
 763                 ct = nf_ct_tuplehash_to_ctrack(h);
 764                 if (nf_ct_is_expired(ct)) {
 765                         nf_ct_gc_expired(ct);
 766                         continue;
 767                 }
 768
 769                 if (nf_ct_key_equal(h, tuple, zone, net))
 770                         return h;
 771         }
 772         /*
 773          * if the nulls value we got at the end of this lookup is
 774          * not the expected one, we must restart lookup.
 775          * We probably met an item that was moved to another chain.
 776          */
 777         if (get_nulls_value(n) != bucket) {
 778                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 779                 goto begin;
 780         }
 781
 782         return NULL;
 783 }
 784
 785 /* Find a connection corresponding to a tuple. */
 786 static struct nf_conntrack_tuple_hash *
 787 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 788                         const struct nf_conntrack_tuple *tuple, u32 hash)
 789 {
 790         struct nf_conntrack_tuple_hash *h;
 791         struct nf_conn *ct;
 792
 793         rcu_read_lock();
 794
 795         h = ____nf_conntrack_find(net, zone, tuple, hash);
 796         if (h) {
 797                 /* We have a candidate that matches the tuple we're interested
 798                  * in, try to obtain a reference and re-check tuple
 799                  */
 800                 ct = nf_ct_tuplehash_to_ctrack(h);
 801                 if (likely(refcount_inc_not_zero(&ct->ct_general.use))) {
 802                         /* re-check key after refcount */
 803                         smp_acquire__after_ctrl_dep();
 804
 805                         if (likely(nf_ct_key_equal(h, tuple, zone, net)))
 806                                 goto found;
 807
 808                         /* TYPESAFE_BY_RCU recycled the candidate */
 809                         nf_ct_put(ct);
 810                 }
 811
 812                 h = NULL;
 813         }
 814 found:
 815         rcu_read_unlock();
 816
 817         return h;
 818 }
 819
 820 struct nf_conntrack_tuple_hash *
 821 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 822                       const struct nf_conntrack_tuple *tuple)
 823 {
 824         unsigned int rid, zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL);
 825         struct nf_conntrack_tuple_hash *thash;
 826
 827         thash = __nf_conntrack_find_get(net, zone, tuple,
 828                                         hash_conntrack_raw(tuple, zone_id, net));
 829
 830         if (thash)
 831                 return thash;
 832
 833         rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY);
 834         if (rid != zone_id)
 835                 return __nf_conntrack_find_get(net, zone, tuple,
 836                                                hash_conntrack_raw(tuple, rid, net));
 837         return thash;
 838 }
 839 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 840
 841 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 842                                        unsigned int hash,
 843                                        unsigned int reply_hash)
 844 {
 845         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 846                            &nf_conntrack_hash[hash]);
 847         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 848                            &nf_conntrack_hash[reply_hash]);
 849 }
 850
 851 static bool nf_ct_ext_valid_pre(const struct nf_ct_ext *ext)
 852 {
 853         /* if ext->gen_id is not equal to nf_conntrack_ext_genid, some extensions
 854          * may contain stale pointers to e.g. helper that has been removed.
 855          *
 856          * The helper can't clear this because the nf_conn object isn't in
 857          * any hash and synchronize_rcu() isn't enough because associated skb
 858          * might sit in a queue.
 859          */
 860         return !ext || ext->gen_id == atomic_read(&nf_conntrack_ext_genid);
 861 }
 862
 863 static bool nf_ct_ext_valid_post(struct nf_ct_ext *ext)
 864 {
 865         if (!ext)
 866                 return true;
 867
 868         if (ext->gen_id != atomic_read(&nf_conntrack_ext_genid))
 869                 return false;
 870
 871         /* inserted into conntrack table, nf_ct_iterate_cleanup()
 872          * will find it.  Disable nf_ct_ext_find() id check.
 873          */
 874         WRITE_ONCE(ext->gen_id, 0);
 875         return true;
 876 }
 877
 878 int
 879 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 880 {
 881         const struct nf_conntrack_zone *zone;
 882         struct net *net = nf_ct_net(ct);
 883         unsigned int hash, reply_hash;
 884         struct nf_conntrack_tuple_hash *h;
 885         struct hlist_nulls_node *n;
 886         unsigned int max_chainlen;
 887         unsigned int chainlen = 0;
 888         unsigned int sequence;
 889         int err = -EEXIST;
 890
 891         zone = nf_ct_zone(ct);
 892
 893         if (!nf_ct_ext_valid_pre(ct->ext))
 894                 return -EAGAIN;
 895
 896         local_bh_disable();
 897         do {
 898                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 899                 hash = hash_conntrack(net,
 900                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 901                                       nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL));
 902                 reply_hash = hash_conntrack(net,
 903                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 904                                            nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
 905         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 906
 907         max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN);
 908
 909         /* See if there's one in the list already, including reverse */
 910         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) {
 911                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 912                                     zone, net))
 913                         goto out;
 914
 915                 if (chainlen++ > max_chainlen)
 916                         goto chaintoolong;
 917         }
 918
 919         chainlen = 0;
 920
 921         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) {
 922                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 923                                     zone, net))
 924                         goto out;
 925                 if (chainlen++ > max_chainlen)
 926                         goto chaintoolong;
 927         }
 928
 929         /* If genid has changed, we can't insert anymore because ct
 930          * extensions could have stale pointers and nf_ct_iterate_destroy
 931          * might have completed its table scan already.
 932          *
 933          * Increment of the ext genid right after this check is fine:
 934          * nf_ct_iterate_destroy blocks until locks are released.
 935          */
 936         if (!nf_ct_ext_valid_post(ct->ext)) {
 937                 err = -EAGAIN;
 938                 goto out;
 939         }
 940
 941         ct->status |= IPS_CONFIRMED;
 942         smp_wmb();
 943         /* The caller holds a reference to this object */
 944         refcount_set(&ct->ct_general.use, 2);
 945         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 946         nf_conntrack_double_unlock(hash, reply_hash);
 947         NF_CT_STAT_INC(net, insert);
 948         local_bh_enable();
 949
 950         return 0;
 951 chaintoolong:
 952         NF_CT_STAT_INC(net, chaintoolong);
 953         err = -ENOSPC;
 954 out:
 955         nf_conntrack_double_unlock(hash, reply_hash);
 956         local_bh_enable();
 957         return err;
 958 }
 959 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 960
 961 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
 962                     unsigned int bytes)
 963 {
 964         struct nf_conn_acct *acct;
 965
 966         acct = nf_conn_acct_find(ct);
 967         if (acct) {
 968                 struct nf_conn_counter *counter = acct->counter;
 969
 970                 atomic64_add(packets, &counter[dir].packets);
 971                 atomic64_add(bytes, &counter[dir].bytes);
 972         }
 973 }
 974 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
 975
 976 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 977                              const struct nf_conn *loser_ct)
 978 {
 979         struct nf_conn_acct *acct;
 980
 981         acct = nf_conn_acct_find(loser_ct);
 982         if (acct) {
 983                 struct nf_conn_counter *counter = acct->counter;
 984                 unsigned int bytes;
 985
 986                 /* u32 should be fine since we must have seen one packet. */
 987                 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
 988                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
 989         }
 990 }
 991
 992 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
 993 {
 994         struct nf_conn_tstamp *tstamp;
 995
 996         refcount_inc(&ct->ct_general.use);
 997
 998         /* set conntrack timestamp, if enabled. */
 999         tstamp = nf_conn_tstamp_find(ct);
1000         if (tstamp)
1001                 tstamp->start = ktime_get_real_ns();
1002 }
1003
1004 /* caller must hold locks to prevent concurrent changes */
1005 static int __nf_ct_resolve_clash(struct sk_buff *skb,
1006                                  struct nf_conntrack_tuple_hash *h)
1007 {
1008         /* This is the conntrack entry already in hashes that won race. */
1009         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1010         enum ip_conntrack_info ctinfo;
1011         struct nf_conn *loser_ct;
1012
1013         loser_ct = nf_ct_get(skb, &ctinfo);
1014
1015         if (nf_ct_is_dying(ct))
1016                 return NF_DROP;
1017
1018         if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
1019             nf_ct_match(ct, loser_ct)) {
1020                 struct net *net = nf_ct_net(ct);
1021
1022                 nf_conntrack_get(&ct->ct_general);
1023
1024                 nf_ct_acct_merge(ct, ctinfo, loser_ct);
1025                 nf_ct_put(loser_ct);
1026                 nf_ct_set(skb, ct, ctinfo);
1027
1028                 NF_CT_STAT_INC(net, clash_resolve);
1029                 return NF_ACCEPT;
1030         }
1031
1032         return NF_DROP;
1033 }
1034
1035 /**
1036  * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
1037  *
1038  * @skb: skb that causes the collision
1039  * @repl_idx: hash slot for reply direction
1040  *
1041  * Called when origin or reply direction had a clash.
1042  * The skb can be handled without packet drop provided the reply direction
1043  * is unique or there the existing entry has the identical tuple in both
1044  * directions.
1045  *
1046  * Caller must hold conntrack table locks to prevent concurrent updates.
1047  *
1048  * Returns NF_DROP if the clash could not be handled.
1049  */
1050 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
1051 {
1052         struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
1053         const struct nf_conntrack_zone *zone;
1054         struct nf_conntrack_tuple_hash *h;
1055         struct hlist_nulls_node *n;
1056         struct net *net;
1057
1058         zone = nf_ct_zone(loser_ct);
1059         net = nf_ct_net(loser_ct);
1060
1061         /* Reply direction must never result in a clash, unless both origin
1062          * and reply tuples are identical.
1063          */
1064         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
1065                 if (nf_ct_key_equal(h,
1066                                     &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1067                                     zone, net))
1068                         return __nf_ct_resolve_clash(skb, h);
1069         }
1070
1071         /* We want the clashing entry to go away real soon: 1 second timeout. */
1072         WRITE_ONCE(loser_ct->timeout, nfct_time_stamp + HZ);
1073
1074         /* IPS_NAT_CLASH removes the entry automatically on the first
1075          * reply.  Also prevents UDP tracker from moving the entry to
1076          * ASSURED state, i.e. the entry can always be evicted under
1077          * pressure.
1078          */
1079         loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
1080
1081         __nf_conntrack_insert_prepare(loser_ct);
1082
1083         /* fake add for ORIGINAL dir: we want lookups to only find the entry
1084          * already in the table.  This also hides the clashing entry from
1085          * ctnetlink iteration, i.e. conntrack -L won't show them.
1086          */
1087         hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
1088
1089         hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
1090                                  &nf_conntrack_hash[repl_idx]);
1091
1092         NF_CT_STAT_INC(net, clash_resolve);
1093         return NF_ACCEPT;
1094 }
1095
1096 /**
1097  * nf_ct_resolve_clash - attempt to handle clash without packet drop
1098  *
1099  * @skb: skb that causes the clash
1100  * @h: tuplehash of the clashing entry already in table
1101  * @reply_hash: hash slot for reply direction
1102  *
1103  * A conntrack entry can be inserted to the connection tracking table
1104  * if there is no existing entry with an identical tuple.
1105  *
1106  * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1107  * to be dropped.  In case @skb is retransmitted, next conntrack lookup
1108  * will find the already-existing entry.
1109  *
1110  * The major problem with such packet drop is the extra delay added by
1111  * the packet loss -- it will take some time for a retransmit to occur
1112  * (or the sender to time out when waiting for a reply).
1113  *
1114  * This function attempts to handle the situation without packet drop.
1115  *
1116  * If @skb has no NAT transformation or if the colliding entries are
1117  * exactly the same, only the to-be-confirmed conntrack entry is discarded
1118  * and @skb is associated with the conntrack entry already in the table.
1119  *
1120  * Failing that, the new, unconfirmed conntrack is still added to the table
1121  * provided that the collision only occurs in the ORIGINAL direction.
1122  * The new entry will be added only in the non-clashing REPLY direction,
1123  * so packets in the ORIGINAL direction will continue to match the existing
1124  * entry.  The new entry will also have a fixed timeout so it expires --
1125  * due to the collision, it will only see reply traffic.
1126  *
1127  * Returns NF_DROP if the clash could not be resolved.
1128  */
1129 static __cold noinline int
1130 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1131                     u32 reply_hash)
1132 {
1133         /* This is the conntrack entry already in hashes that won race. */
1134         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1135         const struct nf_conntrack_l4proto *l4proto;
1136         enum ip_conntrack_info ctinfo;
1137         struct nf_conn *loser_ct;
1138         struct net *net;
1139         int ret;
1140
1141         loser_ct = nf_ct_get(skb, &ctinfo);
1142         net = nf_ct_net(loser_ct);
1143
1144         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1145         if (!l4proto->allow_clash)
1146                 goto drop;
1147
1148         ret = __nf_ct_resolve_clash(skb, h);
1149         if (ret == NF_ACCEPT)
1150                 return ret;
1151
1152         ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1153         if (ret == NF_ACCEPT)
1154                 return ret;
1155
1156 drop:
1157         NF_CT_STAT_INC(net, drop);
1158         NF_CT_STAT_INC(net, insert_failed);
1159         return NF_DROP;
1160 }
1161
1162 /* Confirm a connection given skb; places it in hash table */
1163 int
1164 __nf_conntrack_confirm(struct sk_buff *skb)
1165 {
1166         unsigned int chainlen = 0, sequence, max_chainlen;
1167         const struct nf_conntrack_zone *zone;
1168         unsigned int hash, reply_hash;
1169         struct nf_conntrack_tuple_hash *h;
1170         struct nf_conn *ct;
1171         struct nf_conn_help *help;
1172         struct hlist_nulls_node *n;
1173         enum ip_conntrack_info ctinfo;
1174         struct net *net;
1175         int ret = NF_DROP;
1176
1177         ct = nf_ct_get(skb, &ctinfo);
1178         net = nf_ct_net(ct);
1179
1180         /* ipt_REJECT uses nf_conntrack_attach to attach related
1181            ICMP/TCP RST packets in other direction.  Actual packet
1182            which created connection will be IP_CT_NEW or for an
1183            expected connection, IP_CT_RELATED. */
1184         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1185                 return NF_ACCEPT;
1186
1187         zone = nf_ct_zone(ct);
1188         local_bh_disable();
1189
1190         do {
1191                 sequence = read_seqcount_begin(&nf_conntrack_generation);
1192                 /* reuse the hash saved before */
1193                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1194                 hash = scale_hash(hash);
1195                 reply_hash = hash_conntrack(net,
1196                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1197                                            nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
1198         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1199
1200         /* We're not in hash table, and we refuse to set up related
1201          * connections for unconfirmed conns.  But packet copies and
1202          * REJECT will give spurious warnings here.
1203          */
1204
1205         /* Another skb with the same unconfirmed conntrack may
1206          * win the race. This may happen for bridge(br_flood)
1207          * or broadcast/multicast packets do skb_clone with
1208          * unconfirmed conntrack.
1209          */
1210         if (unlikely(nf_ct_is_confirmed(ct))) {
1211                 WARN_ON_ONCE(1);
1212                 nf_conntrack_double_unlock(hash, reply_hash);
1213                 local_bh_enable();
1214                 return NF_DROP;
1215         }
1216
1217         if (!nf_ct_ext_valid_pre(ct->ext)) {
1218                 NF_CT_STAT_INC(net, insert_failed);
1219                 goto dying;
1220         }
1221
1222         pr_debug("Confirming conntrack %p\n", ct);
1223         /* We have to check the DYING flag after unlink to prevent
1224          * a race against nf_ct_get_next_corpse() possibly called from
1225          * user context, else we insert an already 'dead' hash, blocking
1226          * further use of that particular connection -JM.
1227          */
1228         ct->status |= IPS_CONFIRMED;
1229
1230         if (unlikely(nf_ct_is_dying(ct))) {
1231                 NF_CT_STAT_INC(net, insert_failed);
1232                 goto dying;
1233         }
1234
1235         max_chainlen = MIN_CHAINLEN + prandom_u32_max(MAX_CHAINLEN);
1236         /* See if there's one in the list already, including reverse:
1237            NAT could have grabbed it without realizing, since we're
1238            not in the hash.  If there is, we lost race. */
1239         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) {
1240                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1241                                     zone, net))
1242                         goto out;
1243                 if (chainlen++ > max_chainlen)
1244                         goto chaintoolong;
1245         }
1246
1247         chainlen = 0;
1248         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) {
1249                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1250                                     zone, net))
1251                         goto out;
1252                 if (chainlen++ > max_chainlen) {
1253 chaintoolong:
1254                         NF_CT_STAT_INC(net, chaintoolong);
1255                         NF_CT_STAT_INC(net, insert_failed);
1256                         ret = NF_DROP;
1257                         goto dying;
1258                 }
1259         }
1260
1261         /* Timer relative to confirmation time, not original
1262            setting time, otherwise we'd get timer wrap in
1263            weird delay cases. */
1264         ct->timeout += nfct_time_stamp;
1265
1266         __nf_conntrack_insert_prepare(ct);
1267
1268         /* Since the lookup is lockless, hash insertion must be done after
1269          * starting the timer and setting the CONFIRMED bit. The RCU barriers
1270          * guarantee that no other CPU can find the conntrack before the above
1271          * stores are visible.
1272          */
1273         __nf_conntrack_hash_insert(ct, hash, reply_hash);
1274         nf_conntrack_double_unlock(hash, reply_hash);
1275         local_bh_enable();
1276
1277         /* ext area is still valid (rcu read lock is held,
1278          * but will go out of scope soon, we need to remove
1279          * this conntrack again.
1280          */
1281         if (!nf_ct_ext_valid_post(ct->ext)) {
1282                 nf_ct_kill(ct);
1283                 NF_CT_STAT_INC_ATOMIC(net, drop);
1284                 return NF_DROP;
1285         }
1286
1287         help = nfct_help(ct);
1288         if (help && help->helper)
1289                 nf_conntrack_event_cache(IPCT_HELPER, ct);
1290
1291         nf_conntrack_event_cache(master_ct(ct) ?
1292                                  IPCT_RELATED : IPCT_NEW, ct);
1293         return NF_ACCEPT;
1294
1295 out:
1296         ret = nf_ct_resolve_clash(skb, h, reply_hash);
1297 dying:
1298         nf_conntrack_double_unlock(hash, reply_hash);
1299         local_bh_enable();
1300         return ret;
1301 }
1302 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1303
1304 /* Returns true if a connection correspondings to the tuple (required
1305    for NAT). */
1306 int
1307 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1308                          const struct nf_conn *ignored_conntrack)
1309 {
1310         struct net *net = nf_ct_net(ignored_conntrack);
1311         const struct nf_conntrack_zone *zone;
1312         struct nf_conntrack_tuple_hash *h;
1313         struct hlist_nulls_head *ct_hash;
1314         unsigned int hash, hsize;
1315         struct hlist_nulls_node *n;
1316         struct nf_conn *ct;
1317
1318         zone = nf_ct_zone(ignored_conntrack);
1319
1320         rcu_read_lock();
1321  begin:
1322         nf_conntrack_get_ht(&ct_hash, &hsize);
1323         hash = __hash_conntrack(net, tuple, nf_ct_zone_id(zone, IP_CT_DIR_REPLY), hsize);
1324
1325         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1326                 ct = nf_ct_tuplehash_to_ctrack(h);
1327
1328                 if (ct == ignored_conntrack)
1329                         continue;
1330
1331                 if (nf_ct_is_expired(ct)) {
1332                         nf_ct_gc_expired(ct);
1333                         continue;
1334                 }
1335
1336                 if (nf_ct_key_equal(h, tuple, zone, net)) {
1337                         /* Tuple is taken already, so caller will need to find
1338                          * a new source port to use.
1339                          *
1340                          * Only exception:
1341                          * If the *original tuples* are identical, then both
1342                          * conntracks refer to the same flow.
1343                          * This is a rare situation, it can occur e.g. when
1344                          * more than one UDP packet is sent from same socket
1345                          * in different threads.
1346                          *
1347                          * Let nf_ct_resolve_clash() deal with this later.
1348                          */
1349                         if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1350                                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
1351                                               nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
1352                                 continue;
1353
1354                         NF_CT_STAT_INC_ATOMIC(net, found);
1355                         rcu_read_unlock();
1356                         return 1;
1357                 }
1358         }
1359
1360         if (get_nulls_value(n) != hash) {
1361                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1362                 goto begin;
1363         }
1364
1365         rcu_read_unlock();
1366
1367         return 0;
1368 }
1369 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1370
1371 #define NF_CT_EVICTION_RANGE    8
1372
1373 /* There's a small race here where we may free a just-assured
1374    connection.  Too bad: we're in trouble anyway. */
1375 static unsigned int early_drop_list(struct net *net,
1376                                     struct hlist_nulls_head *head)
1377 {
1378         struct nf_conntrack_tuple_hash *h;
1379         struct hlist_nulls_node *n;
1380         unsigned int drops = 0;
1381         struct nf_conn *tmp;
1382
1383         hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1384                 tmp = nf_ct_tuplehash_to_ctrack(h);
1385
1386                 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1387                         continue;
1388
1389                 if (nf_ct_is_expired(tmp)) {
1390                         nf_ct_gc_expired(tmp);
1391                         continue;
1392                 }
1393
1394                 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1395                     !net_eq(nf_ct_net(tmp), net) ||
1396                     nf_ct_is_dying(tmp))
1397                         continue;
1398
1399                 if (!refcount_inc_not_zero(&tmp->ct_general.use))
1400                         continue;
1401
1402                 /* load ->ct_net and ->status after refcount increase */
1403                 smp_acquire__after_ctrl_dep();
1404
1405                 /* kill only if still in same netns -- might have moved due to
1406                  * SLAB_TYPESAFE_BY_RCU rules.
1407                  *
1408                  * We steal the timer reference.  If that fails timer has
1409                  * already fired or someone else deleted it. Just drop ref
1410                  * and move to next entry.
1411                  */
1412                 if (net_eq(nf_ct_net(tmp), net) &&
1413                     nf_ct_is_confirmed(tmp) &&
1414                     nf_ct_delete(tmp, 0, 0))
1415                         drops++;
1416
1417                 nf_ct_put(tmp);
1418         }
1419
1420         return drops;
1421 }
1422
1423 static noinline int early_drop(struct net *net, unsigned int hash)
1424 {
1425         unsigned int i, bucket;
1426
1427         for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1428                 struct hlist_nulls_head *ct_hash;
1429                 unsigned int hsize, drops;
1430
1431                 rcu_read_lock();
1432                 nf_conntrack_get_ht(&ct_hash, &hsize);
1433                 if (!i)
1434                         bucket = reciprocal_scale(hash, hsize);
1435                 else
1436                         bucket = (bucket + 1) % hsize;
1437
1438                 drops = early_drop_list(net, &ct_hash[bucket]);
1439                 rcu_read_unlock();
1440
1441                 if (drops) {
1442                         NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1443                         return true;
1444                 }
1445         }
1446
1447         return false;
1448 }
1449
1450 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1451 {
1452         return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1453 }
1454
1455 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1456 {
1457         const struct nf_conntrack_l4proto *l4proto;
1458
1459         if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1460                 return true;
1461
1462         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1463         if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1464                 return true;
1465
1466         return false;
1467 }
1468
1469 static void gc_worker(struct work_struct *work)
1470 {
1471         unsigned int i, hashsz, nf_conntrack_max95 = 0;
1472         u32 end_time, start_time = nfct_time_stamp;
1473         struct conntrack_gc_work *gc_work;
1474         unsigned int expired_count = 0;
1475         unsigned long next_run;
1476         s32 delta_time;
1477         long count;
1478
1479         gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1480
1481         i = gc_work->next_bucket;
1482         if (gc_work->early_drop)
1483                 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1484
1485         if (i == 0) {
1486                 gc_work->avg_timeout = GC_SCAN_INTERVAL_INIT;
1487                 gc_work->count = GC_SCAN_INITIAL_COUNT;
1488                 gc_work->start_time = start_time;
1489         }
1490
1491         next_run = gc_work->avg_timeout;
1492         count = gc_work->count;
1493
1494         end_time = start_time + GC_SCAN_MAX_DURATION;
1495
1496         do {
1497                 struct nf_conntrack_tuple_hash *h;
1498                 struct hlist_nulls_head *ct_hash;
1499                 struct hlist_nulls_node *n;
1500                 struct nf_conn *tmp;
1501
1502                 rcu_read_lock();
1503
1504                 nf_conntrack_get_ht(&ct_hash, &hashsz);
1505                 if (i >= hashsz) {
1506                         rcu_read_unlock();
1507                         break;
1508                 }
1509
1510                 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1511                         struct nf_conntrack_net *cnet;
1512                         struct net *net;
1513                         long expires;
1514
1515                         tmp = nf_ct_tuplehash_to_ctrack(h);
1516
1517                         if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1518                                 nf_ct_offload_timeout(tmp);
1519                                 continue;
1520                         }
1521
1522                         if (expired_count > GC_SCAN_EXPIRED_MAX) {
1523                                 rcu_read_unlock();
1524
1525                                 gc_work->next_bucket = i;
1526                                 gc_work->avg_timeout = next_run;
1527                                 gc_work->count = count;
1528
1529                                 delta_time = nfct_time_stamp - gc_work->start_time;
1530
1531                                 /* re-sched immediately if total cycle time is exceeded */
1532                                 next_run = delta_time < (s32)GC_SCAN_INTERVAL_MAX;
1533                                 goto early_exit;
1534                         }
1535
1536                         if (nf_ct_is_expired(tmp)) {
1537                                 nf_ct_gc_expired(tmp);
1538                                 expired_count++;
1539                                 continue;
1540                         }
1541
1542                         expires = clamp(nf_ct_expires(tmp), GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_CLAMP);
1543                         expires = (expires - (long)next_run) / ++count;
1544                         next_run += expires;
1545
1546                         if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1547                                 continue;
1548
1549                         net = nf_ct_net(tmp);
1550                         cnet = nf_ct_pernet(net);
1551                         if (atomic_read(&cnet->count) < nf_conntrack_max95)
1552                                 continue;
1553
1554                         /* need to take reference to avoid possible races */
1555                         if (!refcount_inc_not_zero(&tmp->ct_general.use))
1556                                 continue;
1557
1558                         /* load ->status after refcount increase */
1559                         smp_acquire__after_ctrl_dep();
1560
1561                         if (gc_worker_skip_ct(tmp)) {
1562                                 nf_ct_put(tmp);
1563                                 continue;
1564                         }
1565
1566                         if (gc_worker_can_early_drop(tmp)) {
1567                                 nf_ct_kill(tmp);
1568                                 expired_count++;
1569                         }
1570
1571                         nf_ct_put(tmp);
1572                 }
1573
1574                 /* could check get_nulls_value() here and restart if ct
1575                  * was moved to another chain.  But given gc is best-effort
1576                  * we will just continue with next hash slot.
1577                  */
1578                 rcu_read_unlock();
1579                 cond_resched();
1580                 i++;
1581
1582                 delta_time = nfct_time_stamp - end_time;
1583                 if (delta_time > 0 && i < hashsz) {
1584                         gc_work->avg_timeout = next_run;
1585                         gc_work->count = count;
1586                         gc_work->next_bucket = i;
1587                         next_run = 0;
1588                         goto early_exit;
1589                 }
1590         } while (i < hashsz);
1591
1592         gc_work->next_bucket = 0;
1593
1594         next_run = clamp(next_run, GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_MAX);
1595
1596         delta_time = max_t(s32, nfct_time_stamp - gc_work->start_time, 1);
1597         if (next_run > (unsigned long)delta_time)
1598                 next_run -= delta_time;
1599         else
1600                 next_run = 1;
1601
1602 early_exit:
1603         if (gc_work->exiting)
1604                 return;
1605
1606         if (next_run)
1607                 gc_work->early_drop = false;
1608
1609         queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1610 }
1611
1612 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1613 {
1614         INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
1615         gc_work->exiting = false;
1616 }
1617
1618 static struct nf_conn *
1619 __nf_conntrack_alloc(struct net *net,
1620                      const struct nf_conntrack_zone *zone,
1621                      const struct nf_conntrack_tuple *orig,
1622                      const struct nf_conntrack_tuple *repl,
1623                      gfp_t gfp, u32 hash)
1624 {
1625         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
1626         unsigned int ct_count;
1627         struct nf_conn *ct;
1628
1629         /* We don't want any race condition at early drop stage */
1630         ct_count = atomic_inc_return(&cnet->count);
1631
1632         if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) {
1633                 if (!early_drop(net, hash)) {
1634                         if (!conntrack_gc_work.early_drop)
1635                                 conntrack_gc_work.early_drop = true;
1636                         atomic_dec(&cnet->count);
1637                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1638                         return ERR_PTR(-ENOMEM);
1639                 }
1640         }
1641
1642         /*
1643          * Do not use kmem_cache_zalloc(), as this cache uses
1644          * SLAB_TYPESAFE_BY_RCU.
1645          */
1646         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1647         if (ct == NULL)
1648                 goto out;
1649
1650         spin_lock_init(&ct->lock);
1651         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1652         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1653         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1654         /* save hash for reusing when confirming */
1655         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1656         ct->status = 0;
1657         WRITE_ONCE(ct->timeout, 0);
1658         write_pnet(&ct->ct_net, net);
1659         memset_after(ct, 0, __nfct_init_offset);
1660
1661         nf_ct_zone_add(ct, zone);
1662
1663         /* Because we use RCU lookups, we set ct_general.use to zero before
1664          * this is inserted in any list.
1665          */
1666         refcount_set(&ct->ct_general.use, 0);
1667         return ct;
1668 out:
1669         atomic_dec(&cnet->count);
1670         return ERR_PTR(-ENOMEM);
1671 }
1672
1673 struct nf_conn *nf_conntrack_alloc(struct net *net,
1674                                    const struct nf_conntrack_zone *zone,
1675                                    const struct nf_conntrack_tuple *orig,
1676                                    const struct nf_conntrack_tuple *repl,
1677                                    gfp_t gfp)
1678 {
1679         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1680 }
1681 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1682
1683 void nf_conntrack_free(struct nf_conn *ct)
1684 {
1685         struct net *net = nf_ct_net(ct);
1686         struct nf_conntrack_net *cnet;
1687
1688         /* A freed object has refcnt == 0, that's
1689          * the golden rule for SLAB_TYPESAFE_BY_RCU
1690          */
1691         WARN_ON(refcount_read(&ct->ct_general.use) != 0);
1692
1693         if (ct->status & IPS_SRC_NAT_DONE) {
1694                 const struct nf_nat_hook *nat_hook;
1695
1696                 rcu_read_lock();
1697                 nat_hook = rcu_dereference(nf_nat_hook);
1698                 if (nat_hook)
1699                         nat_hook->remove_nat_bysrc(ct);
1700                 rcu_read_unlock();
1701         }
1702
1703         kfree(ct->ext);
1704         kmem_cache_free(nf_conntrack_cachep, ct);
1705         cnet = nf_ct_pernet(net);
1706
1707         smp_mb__before_atomic();
1708         atomic_dec(&cnet->count);
1709 }
1710 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1711
1712
1713 /* Allocate a new conntrack: we return -ENOMEM if classification
1714    failed due to stress.  Otherwise it really is unclassifiable. */
1715 static noinline struct nf_conntrack_tuple_hash *
1716 init_conntrack(struct net *net, struct nf_conn *tmpl,
1717                const struct nf_conntrack_tuple *tuple,
1718                struct sk_buff *skb,
1719                unsigned int dataoff, u32 hash)
1720 {
1721         struct nf_conn *ct;
1722         struct nf_conn_help *help;
1723         struct nf_conntrack_tuple repl_tuple;
1724 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1725         struct nf_conntrack_ecache *ecache;
1726 #endif
1727         struct nf_conntrack_expect *exp = NULL;
1728         const struct nf_conntrack_zone *zone;
1729         struct nf_conn_timeout *timeout_ext;
1730         struct nf_conntrack_zone tmp;
1731         struct nf_conntrack_net *cnet;
1732
1733         if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1734                 pr_debug("Can't invert tuple.\n");
1735                 return NULL;
1736         }
1737
1738         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1739         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1740                                   hash);
1741         if (IS_ERR(ct))
1742                 return (struct nf_conntrack_tuple_hash *)ct;
1743
1744         if (!nf_ct_add_synproxy(ct, tmpl)) {
1745                 nf_conntrack_free(ct);
1746                 return ERR_PTR(-ENOMEM);
1747         }
1748
1749         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1750
1751         if (timeout_ext)
1752                 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1753                                       GFP_ATOMIC);
1754
1755         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1756         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1757         nf_ct_labels_ext_add(ct);
1758
1759 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1760         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1761
1762         if ((ecache || net->ct.sysctl_events) &&
1763             !nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1764                                   ecache ? ecache->expmask : 0,
1765                                   GFP_ATOMIC)) {
1766                 nf_conntrack_free(ct);
1767                 return ERR_PTR(-ENOMEM);
1768         }
1769 #endif
1770
1771         cnet = nf_ct_pernet(net);
1772         if (cnet->expect_count) {
1773                 spin_lock_bh(&nf_conntrack_expect_lock);
1774                 exp = nf_ct_find_expectation(net, zone, tuple);
1775                 if (exp) {
1776                         pr_debug("expectation arrives ct=%p exp=%p\n",
1777                                  ct, exp);
1778                         /* Welcome, Mr. Bond.  We've been expecting you... */
1779                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
1780                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1781                         ct->master = exp->master;
1782                         if (exp->helper) {
1783                                 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1784                                 if (help)
1785                                         rcu_assign_pointer(help->helper, exp->helper);
1786                         }
1787
1788 #ifdef CONFIG_NF_CONNTRACK_MARK
1789                         ct->mark = READ_ONCE(exp->master->mark);
1790 #endif
1791 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1792                         ct->secmark = exp->master->secmark;
1793 #endif
1794                         NF_CT_STAT_INC(net, expect_new);
1795                 }
1796                 spin_unlock_bh(&nf_conntrack_expect_lock);
1797         }
1798         if (!exp && tmpl)
1799                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1800
1801         /* Other CPU might have obtained a pointer to this object before it was
1802          * released.  Because refcount is 0, refcount_inc_not_zero() will fail.
1803          *
1804          * After refcount_set(1) it will succeed; ensure that zeroing of
1805          * ct->status and the correct ct->net pointer are visible; else other
1806          * core might observe CONFIRMED bit which means the entry is valid and
1807          * in the hash table, but its not (anymore).
1808          */
1809         smp_wmb();
1810
1811         /* Now it is going to be associated with an sk_buff, set refcount to 1. */
1812         refcount_set(&ct->ct_general.use, 1);
1813
1814         if (exp) {
1815                 if (exp->expectfn)
1816                         exp->expectfn(ct, exp);
1817                 nf_ct_expect_put(exp);
1818         }
1819
1820         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1821 }
1822
1823 /* On success, returns 0, sets skb->_nfct | ctinfo */
1824 static int
1825 resolve_normal_ct(struct nf_conn *tmpl,
1826                   struct sk_buff *skb,
1827                   unsigned int dataoff,
1828                   u_int8_t protonum,
1829                   const struct nf_hook_state *state)
1830 {
1831         const struct nf_conntrack_zone *zone;
1832         struct nf_conntrack_tuple tuple;
1833         struct nf_conntrack_tuple_hash *h;
1834         enum ip_conntrack_info ctinfo;
1835         struct nf_conntrack_zone tmp;
1836         u32 hash, zone_id, rid;
1837         struct nf_conn *ct;
1838
1839         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1840                              dataoff, state->pf, protonum, state->net,
1841                              &tuple)) {
1842                 pr_debug("Can't get tuple\n");
1843                 return 0;
1844         }
1845
1846         /* look for tuple match */
1847         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1848
1849         zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL);
1850         hash = hash_conntrack_raw(&tuple, zone_id, state->net);
1851         h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1852
1853         if (!h) {
1854                 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY);
1855                 if (zone_id != rid) {
1856                         u32 tmp = hash_conntrack_raw(&tuple, rid, state->net);
1857
1858                         h = __nf_conntrack_find_get(state->net, zone, &tuple, tmp);
1859                 }
1860         }
1861
1862         if (!h) {
1863                 h = init_conntrack(state->net, tmpl, &tuple,
1864                                    skb, dataoff, hash);
1865                 if (!h)
1866                         return 0;
1867                 if (IS_ERR(h))
1868                         return PTR_ERR(h);
1869         }
1870         ct = nf_ct_tuplehash_to_ctrack(h);
1871
1872         /* It exists; we have (non-exclusive) reference. */
1873         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1874                 ctinfo = IP_CT_ESTABLISHED_REPLY;
1875         } else {
1876                 /* Once we've had two way comms, always ESTABLISHED. */
1877                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1878                         pr_debug("normal packet for %p\n", ct);
1879                         ctinfo = IP_CT_ESTABLISHED;
1880                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1881                         pr_debug("related packet for %p\n", ct);
1882                         ctinfo = IP_CT_RELATED;
1883                 } else {
1884                         pr_debug("new packet for %p\n", ct);
1885                         ctinfo = IP_CT_NEW;
1886                 }
1887         }
1888         nf_ct_set(skb, ct, ctinfo);
1889         return 0;
1890 }
1891
1892 /*
1893  * icmp packets need special treatment to handle error messages that are
1894  * related to a connection.
1895  *
1896  * Callers need to check if skb has a conntrack assigned when this
1897  * helper returns; in such case skb belongs to an already known connection.
1898  */
1899 static unsigned int __cold
1900 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1901                          struct sk_buff *skb,
1902                          unsigned int dataoff,
1903                          u8 protonum,
1904                          const struct nf_hook_state *state)
1905 {
1906         int ret;
1907
1908         if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1909                 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1910 #if IS_ENABLED(CONFIG_IPV6)
1911         else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1912                 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1913 #endif
1914         else
1915                 return NF_ACCEPT;
1916
1917         if (ret <= 0)
1918                 NF_CT_STAT_INC_ATOMIC(state->net, error);
1919
1920         return ret;
1921 }
1922
1923 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1924                           enum ip_conntrack_info ctinfo)
1925 {
1926         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1927
1928         if (!timeout)
1929                 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1930
1931         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1932         return NF_ACCEPT;
1933 }
1934
1935 /* Returns verdict for packet, or -1 for invalid. */
1936 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1937                                       struct sk_buff *skb,
1938                                       unsigned int dataoff,
1939                                       enum ip_conntrack_info ctinfo,
1940                                       const struct nf_hook_state *state)
1941 {
1942         switch (nf_ct_protonum(ct)) {
1943         case IPPROTO_TCP:
1944                 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1945                                                ctinfo, state);
1946         case IPPROTO_UDP:
1947                 return nf_conntrack_udp_packet(ct, skb, dataoff,
1948                                                ctinfo, state);
1949         case IPPROTO_ICMP:
1950                 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1951 #if IS_ENABLED(CONFIG_IPV6)
1952         case IPPROTO_ICMPV6:
1953                 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1954 #endif
1955 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1956         case IPPROTO_UDPLITE:
1957                 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1958                                                    ctinfo, state);
1959 #endif
1960 #ifdef CONFIG_NF_CT_PROTO_SCTP
1961         case IPPROTO_SCTP:
1962                 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1963                                                 ctinfo, state);
1964 #endif
1965 #ifdef CONFIG_NF_CT_PROTO_DCCP
1966         case IPPROTO_DCCP:
1967                 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1968                                                 ctinfo, state);
1969 #endif
1970 #ifdef CONFIG_NF_CT_PROTO_GRE
1971         case IPPROTO_GRE:
1972                 return nf_conntrack_gre_packet(ct, skb, dataoff,
1973                                                ctinfo, state);
1974 #endif
1975         }
1976
1977         return generic_packet(ct, skb, ctinfo);
1978 }
1979
1980 unsigned int
1981 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1982 {
1983         enum ip_conntrack_info ctinfo;
1984         struct nf_conn *ct, *tmpl;
1985         u_int8_t protonum;
1986         int dataoff, ret;
1987
1988         tmpl = nf_ct_get(skb, &ctinfo);
1989         if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1990                 /* Previously seen (loopback or untracked)?  Ignore. */
1991                 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1992                      ctinfo == IP_CT_UNTRACKED)
1993                         return NF_ACCEPT;
1994                 skb->_nfct = 0;
1995         }
1996
1997         /* rcu_read_lock()ed by nf_hook_thresh */
1998         dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1999         if (dataoff <= 0) {
2000                 pr_debug("not prepared to track yet or error occurred\n");
2001                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
2002                 ret = NF_ACCEPT;
2003                 goto out;
2004         }
2005
2006         if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
2007                 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
2008                                                protonum, state);
2009                 if (ret <= 0) {
2010                         ret = -ret;
2011                         goto out;
2012                 }
2013                 /* ICMP[v6] protocol trackers may assign one conntrack. */
2014                 if (skb->_nfct)
2015                         goto out;
2016         }
2017 repeat:
2018         ret = resolve_normal_ct(tmpl, skb, dataoff,
2019                                 protonum, state);
2020         if (ret < 0) {
2021                 /* Too stressed to deal. */
2022                 NF_CT_STAT_INC_ATOMIC(state->net, drop);
2023                 ret = NF_DROP;
2024                 goto out;
2025         }
2026
2027         ct = nf_ct_get(skb, &ctinfo);
2028         if (!ct) {
2029                 /* Not valid part of a connection */
2030                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
2031                 ret = NF_ACCEPT;
2032                 goto out;
2033         }
2034
2035         ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
2036         if (ret <= 0) {
2037                 /* Invalid: inverse of the return code tells
2038                  * the netfilter core what to do */
2039                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
2040                 nf_ct_put(ct);
2041                 skb->_nfct = 0;
2042                 /* Special case: TCP tracker reports an attempt to reopen a
2043                  * closed/aborted connection. We have to go back and create a
2044                  * fresh conntrack.
2045                  */
2046                 if (ret == -NF_REPEAT)
2047                         goto repeat;
2048
2049                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
2050                 if (ret == -NF_DROP)
2051                         NF_CT_STAT_INC_ATOMIC(state->net, drop);
2052
2053                 ret = -ret;
2054                 goto out;
2055         }
2056
2057         if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
2058             !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
2059                 nf_conntrack_event_cache(IPCT_REPLY, ct);
2060 out:
2061         if (tmpl)
2062                 nf_ct_put(tmpl);
2063
2064         return ret;
2065 }
2066 EXPORT_SYMBOL_GPL(nf_conntrack_in);
2067
2068 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
2069    implicitly racy: see __nf_conntrack_confirm */
2070 void nf_conntrack_alter_reply(struct nf_conn *ct,
2071                               const struct nf_conntrack_tuple *newreply)
2072 {
2073         struct nf_conn_help *help = nfct_help(ct);
2074
2075         /* Should be unconfirmed, so not in hash table yet */
2076         WARN_ON(nf_ct_is_confirmed(ct));
2077
2078         pr_debug("Altering reply tuple of %p to ", ct);
2079         nf_ct_dump_tuple(newreply);
2080
2081         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
2082         if (ct->master || (help && !hlist_empty(&help->expectations)))
2083                 return;
2084 }
2085 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
2086
2087 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
2088 void __nf_ct_refresh_acct(struct nf_conn *ct,
2089                           enum ip_conntrack_info ctinfo,
2090                           const struct sk_buff *skb,
2091                           u32 extra_jiffies,
2092                           bool do_acct)
2093 {
2094         /* Only update if this is not a fixed timeout */
2095         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
2096                 goto acct;
2097
2098         /* If not in hash table, timer will not be active yet */
2099         if (nf_ct_is_confirmed(ct))
2100                 extra_jiffies += nfct_time_stamp;
2101
2102         if (READ_ONCE(ct->timeout) != extra_jiffies)
2103                 WRITE_ONCE(ct->timeout, extra_jiffies);
2104 acct:
2105         if (do_acct)
2106                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
2107 }
2108 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
2109
2110 bool nf_ct_kill_acct(struct nf_conn *ct,
2111                      enum ip_conntrack_info ctinfo,
2112                      const struct sk_buff *skb)
2113 {
2114         nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
2115
2116         return nf_ct_delete(ct, 0, 0);
2117 }
2118 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
2119
2120 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
2121
2122 #include <linux/netfilter/nfnetlink.h>
2123 #include <linux/netfilter/nfnetlink_conntrack.h>
2124 #include <linux/mutex.h>
2125
2126 /* Generic function for tcp/udp/sctp/dccp and alike. */
2127 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
2128                                const struct nf_conntrack_tuple *tuple)
2129 {
2130         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
2131             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
2132                 goto nla_put_failure;
2133         return 0;
2134
2135 nla_put_failure:
2136         return -1;
2137 }
2138 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
2139
2140 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
2141         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
2142         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
2143 };
2144 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
2145
2146 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
2147                                struct nf_conntrack_tuple *t,
2148                                u_int32_t flags)
2149 {
2150         if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
2151                 if (!tb[CTA_PROTO_SRC_PORT])
2152                         return -EINVAL;
2153
2154                 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
2155         }
2156
2157         if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
2158                 if (!tb[CTA_PROTO_DST_PORT])
2159                         return -EINVAL;
2160
2161                 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
2162         }
2163
2164         return 0;
2165 }
2166 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
2167
2168 unsigned int nf_ct_port_nlattr_tuple_size(void)
2169 {
2170         static unsigned int size __read_mostly;
2171
2172         if (!size)
2173                 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
2174
2175         return size;
2176 }
2177 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
2178 #endif
2179
2180 /* Used by ipt_REJECT and ip6t_REJECT. */
2181 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
2182 {
2183         struct nf_conn *ct;
2184         enum ip_conntrack_info ctinfo;
2185
2186         /* This ICMP is in reverse direction to the packet which caused it */
2187         ct = nf_ct_get(skb, &ctinfo);
2188         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2189                 ctinfo = IP_CT_RELATED_REPLY;
2190         else
2191                 ctinfo = IP_CT_RELATED;
2192
2193         /* Attach to new skbuff, and increment count */
2194         nf_ct_set(nskb, ct, ctinfo);
2195         nf_conntrack_get(skb_nfct(nskb));
2196 }
2197
2198 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2199                                  struct nf_conn *ct,
2200                                  enum ip_conntrack_info ctinfo)
2201 {
2202         const struct nf_nat_hook *nat_hook;
2203         struct nf_conntrack_tuple_hash *h;
2204         struct nf_conntrack_tuple tuple;
2205         unsigned int status;
2206         int dataoff;
2207         u16 l3num;
2208         u8 l4num;
2209
2210         l3num = nf_ct_l3num(ct);
2211
2212         dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2213         if (dataoff <= 0)
2214                 return -1;
2215
2216         if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2217                              l4num, net, &tuple))
2218                 return -1;
2219
2220         if (ct->status & IPS_SRC_NAT) {
2221                 memcpy(tuple.src.u3.all,
2222                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2223                        sizeof(tuple.src.u3.all));
2224                 tuple.src.u.all =
2225                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2226         }
2227
2228         if (ct->status & IPS_DST_NAT) {
2229                 memcpy(tuple.dst.u3.all,
2230                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2231                        sizeof(tuple.dst.u3.all));
2232                 tuple.dst.u.all =
2233                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2234         }
2235
2236         h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2237         if (!h)
2238                 return 0;
2239
2240         /* Store status bits of the conntrack that is clashing to re-do NAT
2241          * mangling according to what it has been done already to this packet.
2242          */
2243         status = ct->status;
2244
2245         nf_ct_put(ct);
2246         ct = nf_ct_tuplehash_to_ctrack(h);
2247         nf_ct_set(skb, ct, ctinfo);
2248
2249         nat_hook = rcu_dereference(nf_nat_hook);
2250         if (!nat_hook)
2251                 return 0;
2252
2253         if (status & IPS_SRC_NAT &&
2254             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2255                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2256                 return -1;
2257
2258         if (status & IPS_DST_NAT &&
2259             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2260                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2261                 return -1;
2262
2263         return 0;
2264 }
2265
2266 /* This packet is coming from userspace via nf_queue, complete the packet
2267  * processing after the helper invocation in nf_confirm().
2268  */
2269 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2270                                enum ip_conntrack_info ctinfo)
2271 {
2272         const struct nf_conntrack_helper *helper;
2273         const struct nf_conn_help *help;
2274         int protoff;
2275
2276         help = nfct_help(ct);
2277         if (!help)
2278                 return 0;
2279
2280         helper = rcu_dereference(help->helper);
2281         if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2282                 return 0;
2283
2284         switch (nf_ct_l3num(ct)) {
2285         case NFPROTO_IPV4:
2286                 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2287                 break;
2288 #if IS_ENABLED(CONFIG_IPV6)
2289         case NFPROTO_IPV6: {
2290                 __be16 frag_off;
2291                 u8 pnum;
2292
2293                 pnum = ipv6_hdr(skb)->nexthdr;
2294                 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2295                                            &frag_off);
2296                 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2297                         return 0;
2298                 break;
2299         }
2300 #endif
2301         default:
2302                 return 0;
2303         }
2304
2305         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2306             !nf_is_loopback_packet(skb)) {
2307                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2308                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2309                         return -1;
2310                 }
2311         }
2312
2313         /* We've seen it coming out the other side: confirm it */
2314         return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2315 }
2316
2317 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2318 {
2319         enum ip_conntrack_info ctinfo;
2320         struct nf_conn *ct;
2321         int err;
2322
2323         ct = nf_ct_get(skb, &ctinfo);
2324         if (!ct)
2325                 return 0;
2326
2327         if (!nf_ct_is_confirmed(ct)) {
2328                 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2329                 if (err < 0)
2330                         return err;
2331
2332                 ct = nf_ct_get(skb, &ctinfo);
2333         }
2334
2335         return nf_confirm_cthelper(skb, ct, ctinfo);
2336 }
2337
2338 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2339                                        const struct sk_buff *skb)
2340 {
2341         const struct nf_conntrack_tuple *src_tuple;
2342         const struct nf_conntrack_tuple_hash *hash;
2343         struct nf_conntrack_tuple srctuple;
2344         enum ip_conntrack_info ctinfo;
2345         struct nf_conn *ct;
2346
2347         ct = nf_ct_get(skb, &ctinfo);
2348         if (ct) {
2349                 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2350                 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2351                 return true;
2352         }
2353
2354         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2355                                NFPROTO_IPV4, dev_net(skb->dev),
2356                                &srctuple))
2357                 return false;
2358
2359         hash = nf_conntrack_find_get(dev_net(skb->dev),
2360                                      &nf_ct_zone_dflt,
2361                                      &srctuple);
2362         if (!hash)
2363                 return false;
2364
2365         ct = nf_ct_tuplehash_to_ctrack(hash);
2366         src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2367         memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2368         nf_ct_put(ct);
2369
2370         return true;
2371 }
2372
2373 /* Bring out ya dead! */
2374 static struct nf_conn *
2375 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2376                 const struct nf_ct_iter_data *iter_data, unsigned int *bucket)
2377 {
2378         struct nf_conntrack_tuple_hash *h;
2379         struct nf_conn *ct;
2380         struct hlist_nulls_node *n;
2381         spinlock_t *lockp;
2382
2383         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2384                 struct hlist_nulls_head *hslot = &nf_conntrack_hash[*bucket];
2385
2386                 if (hlist_nulls_empty(hslot))
2387                         continue;
2388
2389                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2390                 local_bh_disable();
2391                 nf_conntrack_lock(lockp);
2392                 hlist_nulls_for_each_entry(h, n, hslot, hnnode) {
2393                         if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2394                                 continue;
2395                         /* All nf_conn objects are added to hash table twice, one
2396                          * for original direction tuple, once for the reply tuple.
2397                          *
2398                          * Exception: In the IPS_NAT_CLASH case, only the reply
2399                          * tuple is added (the original tuple already existed for
2400                          * a different object).
2401                          *
2402                          * We only need to call the iterator once for each
2403                          * conntrack, so we just use the 'reply' direction
2404                          * tuple while iterating.
2405                          */
2406                         ct = nf_ct_tuplehash_to_ctrack(h);
2407
2408                         if (iter_data->net &&
2409                             !net_eq(iter_data->net, nf_ct_net(ct)))
2410                                 continue;
2411
2412                         if (iter(ct, iter_data->data))
2413                                 goto found;
2414                 }
2415                 spin_unlock(lockp);
2416                 local_bh_enable();
2417                 cond_resched();
2418         }
2419
2420         return NULL;
2421 found:
2422         refcount_inc(&ct->ct_general.use);
2423         spin_unlock(lockp);
2424         local_bh_enable();
2425         return ct;
2426 }
2427
2428 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2429                                   const struct nf_ct_iter_data *iter_data)
2430 {
2431         unsigned int bucket = 0;
2432         struct nf_conn *ct;
2433
2434         might_sleep();
2435
2436         mutex_lock(&nf_conntrack_mutex);
2437         while ((ct = get_next_corpse(iter, iter_data, &bucket)) != NULL) {
2438                 /* Time to push up daises... */
2439
2440                 nf_ct_delete(ct, iter_data->portid, iter_data->report);
2441                 nf_ct_put(ct);
2442                 cond_resched();
2443         }
2444         mutex_unlock(&nf_conntrack_mutex);
2445 }
2446
2447 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
2448                                const struct nf_ct_iter_data *iter_data)
2449 {
2450         struct net *net = iter_data->net;
2451         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2452
2453         might_sleep();
2454
2455         if (atomic_read(&cnet->count) == 0)
2456                 return;
2457
2458         nf_ct_iterate_cleanup(iter, iter_data);
2459 }
2460 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2461
2462 /**
2463  * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2464  * @iter: callback to invoke for each conntrack
2465  * @data: data to pass to @iter
2466  *
2467  * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2468  * unconfirmed list as dying (so they will not be inserted into
2469  * main table).
2470  *
2471  * Can only be called in module exit path.
2472  */
2473 void
2474 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2475 {
2476         struct nf_ct_iter_data iter_data = {};
2477         struct net *net;
2478
2479         down_read(&net_rwsem);
2480         for_each_net(net) {
2481                 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2482
2483                 if (atomic_read(&cnet->count) == 0)
2484                         continue;
2485                 nf_queue_nf_hook_drop(net);
2486         }
2487         up_read(&net_rwsem);
2488
2489         /* Need to wait for netns cleanup worker to finish, if its
2490          * running -- it might have deleted a net namespace from
2491          * the global list, so hook drop above might not have
2492          * affected all namespaces.
2493          */
2494         net_ns_barrier();
2495
2496         /* a skb w. unconfirmed conntrack could have been reinjected just
2497          * before we called nf_queue_nf_hook_drop().
2498          *
2499          * This makes sure its inserted into conntrack table.
2500          */
2501         synchronize_net();
2502
2503         nf_ct_ext_bump_genid();
2504         iter_data.data = data;
2505         nf_ct_iterate_cleanup(iter, &iter_data);
2506
2507         /* Another cpu might be in a rcu read section with
2508          * rcu protected pointer cleared in iter callback
2509          * or hidden via nf_ct_ext_bump_genid() above.
2510          *
2511          * Wait until those are done.
2512          */
2513         synchronize_rcu();
2514 }
2515 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2516
2517 static int kill_all(struct nf_conn *i, void *data)
2518 {
2519         return 1;
2520 }
2521
2522 void nf_conntrack_cleanup_start(void)
2523 {
2524         cleanup_nf_conntrack_bpf();
2525         conntrack_gc_work.exiting = true;
2526 }
2527
2528 void nf_conntrack_cleanup_end(void)
2529 {
2530         RCU_INIT_POINTER(nf_ct_hook, NULL);
2531         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2532         kvfree(nf_conntrack_hash);
2533
2534         nf_conntrack_proto_fini();
2535         nf_conntrack_helper_fini();
2536         nf_conntrack_expect_fini();
2537
2538         kmem_cache_destroy(nf_conntrack_cachep);
2539 }
2540
2541 /*
2542  * Mishearing the voices in his head, our hero wonders how he's
2543  * supposed to kill the mall.
2544  */
2545 void nf_conntrack_cleanup_net(struct net *net)
2546 {
2547         LIST_HEAD(single);
2548
2549         list_add(&net->exit_list, &single);
2550         nf_conntrack_cleanup_net_list(&single);
2551 }
2552
2553 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2554 {
2555         struct nf_ct_iter_data iter_data = {};
2556         struct net *net;
2557         int busy;
2558
2559         /*
2560          * This makes sure all current packets have passed through
2561          *  netfilter framework.  Roll on, two-stage module
2562          *  delete...
2563          */
2564         synchronize_net();
2565 i_see_dead_people:
2566         busy = 0;
2567         list_for_each_entry(net, net_exit_list, exit_list) {
2568                 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2569
2570                 iter_data.net = net;
2571                 nf_ct_iterate_cleanup_net(kill_all, &iter_data);
2572                 if (atomic_read(&cnet->count) != 0)
2573                         busy = 1;
2574         }
2575         if (busy) {
2576                 schedule();
2577                 goto i_see_dead_people;
2578         }
2579
2580         list_for_each_entry(net, net_exit_list, exit_list) {
2581                 nf_conntrack_ecache_pernet_fini(net);
2582                 nf_conntrack_expect_pernet_fini(net);
2583                 free_percpu(net->ct.stat);
2584         }
2585 }
2586
2587 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2588 {
2589         struct hlist_nulls_head *hash;
2590         unsigned int nr_slots, i;
2591
2592         if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2593                 return NULL;
2594
2595         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2596         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2597
2598         hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2599
2600         if (hash && nulls)
2601                 for (i = 0; i < nr_slots; i++)
2602                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
2603
2604         return hash;
2605 }
2606 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2607
2608 int nf_conntrack_hash_resize(unsigned int hashsize)
2609 {
2610         int i, bucket;
2611         unsigned int old_size;
2612         struct hlist_nulls_head *hash, *old_hash;
2613         struct nf_conntrack_tuple_hash *h;
2614         struct nf_conn *ct;
2615
2616         if (!hashsize)
2617                 return -EINVAL;
2618
2619         hash = nf_ct_alloc_hashtable(&hashsize, 1);
2620         if (!hash)
2621                 return -ENOMEM;
2622
2623         mutex_lock(&nf_conntrack_mutex);
2624         old_size = nf_conntrack_htable_size;
2625         if (old_size == hashsize) {
2626                 mutex_unlock(&nf_conntrack_mutex);
2627                 kvfree(hash);
2628                 return 0;
2629         }
2630
2631         local_bh_disable();
2632         nf_conntrack_all_lock();
2633         write_seqcount_begin(&nf_conntrack_generation);
2634
2635         /* Lookups in the old hash might happen in parallel, which means we
2636          * might get false negatives during connection lookup. New connections
2637          * created because of a false negative won't make it into the hash
2638          * though since that required taking the locks.
2639          */
2640
2641         for (i = 0; i < nf_conntrack_htable_size; i++) {
2642                 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2643                         unsigned int zone_id;
2644
2645                         h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2646                                               struct nf_conntrack_tuple_hash, hnnode);
2647                         ct = nf_ct_tuplehash_to_ctrack(h);
2648                         hlist_nulls_del_rcu(&h->hnnode);
2649
2650                         zone_id = nf_ct_zone_id(nf_ct_zone(ct), NF_CT_DIRECTION(h));
2651                         bucket = __hash_conntrack(nf_ct_net(ct),
2652                                                   &h->tuple, zone_id, hashsize);
2653                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2654                 }
2655         }
2656         old_hash = nf_conntrack_hash;
2657
2658         nf_conntrack_hash = hash;
2659         nf_conntrack_htable_size = hashsize;
2660
2661         write_seqcount_end(&nf_conntrack_generation);
2662         nf_conntrack_all_unlock();
2663         local_bh_enable();
2664
2665         mutex_unlock(&nf_conntrack_mutex);
2666
2667         synchronize_net();
2668         kvfree(old_hash);
2669         return 0;
2670 }
2671
2672 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2673 {
2674         unsigned int hashsize;
2675         int rc;
2676
2677         if (current->nsproxy->net_ns != &init_net)
2678                 return -EOPNOTSUPP;
2679
2680         /* On boot, we can set this without any fancy locking. */
2681         if (!nf_conntrack_hash)
2682                 return param_set_uint(val, kp);
2683
2684         rc = kstrtouint(val, 0, &hashsize);
2685         if (rc)
2686                 return rc;
2687
2688         return nf_conntrack_hash_resize(hashsize);
2689 }
2690
2691 int nf_conntrack_init_start(void)
2692 {
2693         unsigned long nr_pages = totalram_pages();
2694         int max_factor = 8;
2695         int ret = -ENOMEM;
2696         int i;
2697
2698         seqcount_spinlock_init(&nf_conntrack_generation,
2699                                &nf_conntrack_locks_all_lock);
2700
2701         for (i = 0; i < CONNTRACK_LOCKS; i++)
2702                 spin_lock_init(&nf_conntrack_locks[i]);
2703
2704         if (!nf_conntrack_htable_size) {
2705                 nf_conntrack_htable_size
2706                         = (((nr_pages << PAGE_SHIFT) / 16384)
2707                            / sizeof(struct hlist_head));
2708                 if (BITS_PER_LONG >= 64 &&
2709                     nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2710                         nf_conntrack_htable_size = 262144;
2711                 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2712                         nf_conntrack_htable_size = 65536;
2713
2714                 if (nf_conntrack_htable_size < 1024)
2715                         nf_conntrack_htable_size = 1024;
2716                 /* Use a max. factor of one by default to keep the average
2717                  * hash chain length at 2 entries.  Each entry has to be added
2718                  * twice (once for original direction, once for reply).
2719                  * When a table size is given we use the old value of 8 to
2720                  * avoid implicit reduction of the max entries setting.
2721                  */
2722                 max_factor = 1;
2723         }
2724
2725         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2726         if (!nf_conntrack_hash)
2727                 return -ENOMEM;
2728
2729         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2730
2731         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2732                                                 sizeof(struct nf_conn),
2733                                                 NFCT_INFOMASK + 1,
2734                                                 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2735         if (!nf_conntrack_cachep)
2736                 goto err_cachep;
2737
2738         ret = nf_conntrack_expect_init();
2739         if (ret < 0)
2740                 goto err_expect;
2741
2742         ret = nf_conntrack_helper_init();
2743         if (ret < 0)
2744                 goto err_helper;
2745
2746         ret = nf_conntrack_proto_init();
2747         if (ret < 0)
2748                 goto err_proto;
2749
2750         conntrack_gc_work_init(&conntrack_gc_work);
2751         queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2752
2753         ret = register_nf_conntrack_bpf();
2754         if (ret < 0)
2755                 goto err_kfunc;
2756
2757         return 0;
2758
2759 err_kfunc:
2760         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2761         nf_conntrack_proto_fini();
2762 err_proto:
2763         nf_conntrack_helper_fini();
2764 err_helper:
2765         nf_conntrack_expect_fini();
2766 err_expect:
2767         kmem_cache_destroy(nf_conntrack_cachep);
2768 err_cachep:
2769         kvfree(nf_conntrack_hash);
2770         return ret;
2771 }
2772
2773 static const struct nf_ct_hook nf_conntrack_hook = {
2774         .update         = nf_conntrack_update,
2775         .destroy        = nf_ct_destroy,
2776         .get_tuple_skb  = nf_conntrack_get_tuple_skb,
2777         .attach         = nf_conntrack_attach,
2778 };
2779
2780 void nf_conntrack_init_end(void)
2781 {
2782         RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2783 }
2784
2785 /*
2786  * We need to use special "null" values, not used in hash table
2787  */
2788 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
2789
2790 int nf_conntrack_init_net(struct net *net)
2791 {
2792         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2793         int ret = -ENOMEM;
2794
2795         BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2796         BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2797         atomic_set(&cnet->count, 0);
2798
2799         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2800         if (!net->ct.stat)
2801                 return ret;
2802
2803         ret = nf_conntrack_expect_pernet_init(net);
2804         if (ret < 0)
2805                 goto err_expect;
2806
2807         nf_conntrack_acct_pernet_init(net);
2808         nf_conntrack_tstamp_pernet_init(net);
2809         nf_conntrack_ecache_pernet_init(net);
2810         nf_conntrack_proto_pernet_init(net);
2811
2812         return 0;
2813
2814 err_expect:
2815         free_percpu(net->ct.stat);
2816         return ret;
2817 }
2818
2819 /* ctnetlink code shared by both ctnetlink and nf_conntrack_bpf */
2820
2821 int __nf_ct_change_timeout(struct nf_conn *ct, u64 timeout)
2822 {
2823         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
2824                 return -EPERM;
2825
2826         __nf_ct_set_timeout(ct, timeout);
2827
2828         if (test_bit(IPS_DYING_BIT, &ct->status))
2829                 return -ETIME;
2830
2831         return 0;
2832 }
2833 EXPORT_SYMBOL_GPL(__nf_ct_change_timeout);
2834
2835 void __nf_ct_change_status(struct nf_conn *ct, unsigned long on, unsigned long off)
2836 {
2837         unsigned int bit;
2838
2839         /* Ignore these unchangable bits */
2840         on &= ~IPS_UNCHANGEABLE_MASK;
2841         off &= ~IPS_UNCHANGEABLE_MASK;
2842
2843         for (bit = 0; bit < __IPS_MAX_BIT; bit++) {
2844                 if (on & (1 << bit))
2845                         set_bit(bit, &ct->status);
2846                 else if (off & (1 << bit))
2847                         clear_bit(bit, &ct->status);
2848         }
2849 }
2850 EXPORT_SYMBOL_GPL(__nf_ct_change_status);
2851
2852 int nf_ct_change_status_common(struct nf_conn *ct, unsigned int status)
2853 {
2854         unsigned long d;
2855
2856         d = ct->status ^ status;
2857
2858         if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING))
2859                 /* unchangeable */
2860                 return -EBUSY;
2861
2862         if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
2863                 /* SEEN_REPLY bit can only be set */
2864                 return -EBUSY;
2865
2866         if (d & IPS_ASSURED && !(status & IPS_ASSURED))
2867                 /* ASSURED bit can only be set */
2868                 return -EBUSY;
2869
2870         __nf_ct_change_status(ct, status, 0);
2871         return 0;
2872 }
2873 EXPORT_SYMBOL_GPL(nf_ct_change_status_common);