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    8u
 100 #define MAX_CHAINLEN    (32u - 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         u64 a, b, c, d;
 215
 216         get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
 217
 218         /* The direction must be ignored, handle usable tuplehash members manually */
 219         a = (u64)tuple->src.u3.all[0] << 32 | tuple->src.u3.all[3];
 220         b = (u64)tuple->dst.u3.all[0] << 32 | tuple->dst.u3.all[3];
 221
 222         c = (__force u64)tuple->src.u.all << 32 | (__force u64)tuple->dst.u.all << 16;
 223         c |= tuple->dst.protonum;
 224
 225         d = (u64)zoneid << 32 | net_hash_mix(net);
 226
 227         /* IPv4: u3.all[1,2,3] == 0 */
 228         c ^= (u64)tuple->src.u3.all[1] << 32 | tuple->src.u3.all[2];
 229         d += (u64)tuple->dst.u3.all[1] << 32 | tuple->dst.u3.all[2];
 230
 231         return (u32)siphash_4u64(a, b, c, d, &nf_conntrack_hash_rnd);
 232 }
 233
 234 static u32 scale_hash(u32 hash)
 235 {
 236         return reciprocal_scale(hash, nf_conntrack_htable_size);
 237 }
 238
 239 static u32 __hash_conntrack(const struct net *net,
 240                             const struct nf_conntrack_tuple *tuple,
 241                             unsigned int zoneid,
 242                             unsigned int size)
 243 {
 244         return reciprocal_scale(hash_conntrack_raw(tuple, zoneid, net), size);
 245 }
 246
 247 static u32 hash_conntrack(const struct net *net,
 248                           const struct nf_conntrack_tuple *tuple,
 249                           unsigned int zoneid)
 250 {
 251         return scale_hash(hash_conntrack_raw(tuple, zoneid, net));
 252 }
 253
 254 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
 255                                   unsigned int dataoff,
 256                                   struct nf_conntrack_tuple *tuple)
 257 {       struct {
 258                 __be16 sport;
 259                 __be16 dport;
 260         } _inet_hdr, *inet_hdr;
 261
 262         /* Actually only need first 4 bytes to get ports. */
 263         inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
 264         if (!inet_hdr)
 265                 return false;
 266
 267         tuple->src.u.udp.port = inet_hdr->sport;
 268         tuple->dst.u.udp.port = inet_hdr->dport;
 269         return true;
 270 }
 271
 272 static bool
 273 nf_ct_get_tuple(const struct sk_buff *skb,
 274                 unsigned int nhoff,
 275                 unsigned int dataoff,
 276                 u_int16_t l3num,
 277                 u_int8_t protonum,
 278                 struct net *net,
 279                 struct nf_conntrack_tuple *tuple)
 280 {
 281         unsigned int size;
 282         const __be32 *ap;
 283         __be32 _addrs[8];
 284
 285         memset(tuple, 0, sizeof(*tuple));
 286
 287         tuple->src.l3num = l3num;
 288         switch (l3num) {
 289         case NFPROTO_IPV4:
 290                 nhoff += offsetof(struct iphdr, saddr);
 291                 size = 2 * sizeof(__be32);
 292                 break;
 293         case NFPROTO_IPV6:
 294                 nhoff += offsetof(struct ipv6hdr, saddr);
 295                 size = sizeof(_addrs);
 296                 break;
 297         default:
 298                 return true;
 299         }
 300
 301         ap = skb_header_pointer(skb, nhoff, size, _addrs);
 302         if (!ap)
 303                 return false;
 304
 305         switch (l3num) {
 306         case NFPROTO_IPV4:
 307                 tuple->src.u3.ip = ap[0];
 308                 tuple->dst.u3.ip = ap[1];
 309                 break;
 310         case NFPROTO_IPV6:
 311                 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
 312                 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
 313                 break;
 314         }
 315
 316         tuple->dst.protonum = protonum;
 317         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 318
 319         switch (protonum) {
 320 #if IS_ENABLED(CONFIG_IPV6)
 321         case IPPROTO_ICMPV6:
 322                 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
 323 #endif
 324         case IPPROTO_ICMP:
 325                 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
 326 #ifdef CONFIG_NF_CT_PROTO_GRE
 327         case IPPROTO_GRE:
 328                 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
 329 #endif
 330         case IPPROTO_TCP:
 331         case IPPROTO_UDP:
 332 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
 333         case IPPROTO_UDPLITE:
 334 #endif
 335 #ifdef CONFIG_NF_CT_PROTO_SCTP
 336         case IPPROTO_SCTP:
 337 #endif
 338 #ifdef CONFIG_NF_CT_PROTO_DCCP
 339         case IPPROTO_DCCP:
 340 #endif
 341                 /* fallthrough */
 342                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 343         default:
 344                 break;
 345         }
 346
 347         return true;
 348 }
 349
 350 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 351                             u_int8_t *protonum)
 352 {
 353         int dataoff = -1;
 354         const struct iphdr *iph;
 355         struct iphdr _iph;
 356
 357         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
 358         if (!iph)
 359                 return -1;
 360
 361         /* Conntrack defragments packets, we might still see fragments
 362          * inside ICMP packets though.
 363          */
 364         if (iph->frag_off & htons(IP_OFFSET))
 365                 return -1;
 366
 367         dataoff = nhoff + (iph->ihl << 2);
 368         *protonum = iph->protocol;
 369
 370         /* Check bogus IP headers */
 371         if (dataoff > skb->len) {
 372                 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
 373                          nhoff, iph->ihl << 2, skb->len);
 374                 return -1;
 375         }
 376         return dataoff;
 377 }
 378
 379 #if IS_ENABLED(CONFIG_IPV6)
 380 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 381                             u8 *protonum)
 382 {
 383         int protoff = -1;
 384         unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
 385         __be16 frag_off;
 386         u8 nexthdr;
 387
 388         if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
 389                           &nexthdr, sizeof(nexthdr)) != 0) {
 390                 pr_debug("can't get nexthdr\n");
 391                 return -1;
 392         }
 393         protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
 394         /*
 395          * (protoff == skb->len) means the packet has not data, just
 396          * IPv6 and possibly extensions headers, but it is tracked anyway
 397          */
 398         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 399                 pr_debug("can't find proto in pkt\n");
 400                 return -1;
 401         }
 402
 403         *protonum = nexthdr;
 404         return protoff;
 405 }
 406 #endif
 407
 408 static int get_l4proto(const struct sk_buff *skb,
 409                        unsigned int nhoff, u8 pf, u8 *l4num)
 410 {
 411         switch (pf) {
 412         case NFPROTO_IPV4:
 413                 return ipv4_get_l4proto(skb, nhoff, l4num);
 414 #if IS_ENABLED(CONFIG_IPV6)
 415         case NFPROTO_IPV6:
 416                 return ipv6_get_l4proto(skb, nhoff, l4num);
 417 #endif
 418         default:
 419                 *l4num = 0;
 420                 break;
 421         }
 422         return -1;
 423 }
 424
 425 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 426                        u_int16_t l3num,
 427                        struct net *net, struct nf_conntrack_tuple *tuple)
 428 {
 429         u8 protonum;
 430         int protoff;
 431
 432         protoff = get_l4proto(skb, nhoff, l3num, &protonum);
 433         if (protoff <= 0)
 434                 return false;
 435
 436         return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
 437 }
 438 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 439
 440 bool
 441 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 442                    const struct nf_conntrack_tuple *orig)
 443 {
 444         memset(inverse, 0, sizeof(*inverse));
 445
 446         inverse->src.l3num = orig->src.l3num;
 447
 448         switch (orig->src.l3num) {
 449         case NFPROTO_IPV4:
 450                 inverse->src.u3.ip = orig->dst.u3.ip;
 451                 inverse->dst.u3.ip = orig->src.u3.ip;
 452                 break;
 453         case NFPROTO_IPV6:
 454                 inverse->src.u3.in6 = orig->dst.u3.in6;
 455                 inverse->dst.u3.in6 = orig->src.u3.in6;
 456                 break;
 457         default:
 458                 break;
 459         }
 460
 461         inverse->dst.dir = !orig->dst.dir;
 462
 463         inverse->dst.protonum = orig->dst.protonum;
 464
 465         switch (orig->dst.protonum) {
 466         case IPPROTO_ICMP:
 467                 return nf_conntrack_invert_icmp_tuple(inverse, orig);
 468 #if IS_ENABLED(CONFIG_IPV6)
 469         case IPPROTO_ICMPV6:
 470                 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
 471 #endif
 472         }
 473
 474         inverse->src.u.all = orig->dst.u.all;
 475         inverse->dst.u.all = orig->src.u.all;
 476         return true;
 477 }
 478 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 479
 480 /* Generate a almost-unique pseudo-id for a given conntrack.
 481  *
 482  * intentionally doesn't re-use any of the seeds used for hash
 483  * table location, we assume id gets exposed to userspace.
 484  *
 485  * Following nf_conn items do not change throughout lifetime
 486  * of the nf_conn:
 487  *
 488  * 1. nf_conn address
 489  * 2. nf_conn->master address (normally NULL)
 490  * 3. the associated net namespace
 491  * 4. the original direction tuple
 492  */
 493 u32 nf_ct_get_id(const struct nf_conn *ct)
 494 {
 495         static siphash_aligned_key_t ct_id_seed;
 496         unsigned long a, b, c, d;
 497
 498         net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
 499
 500         a = (unsigned long)ct;
 501         b = (unsigned long)ct->master;
 502         c = (unsigned long)nf_ct_net(ct);
 503         d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 504                                    sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
 505                                    &ct_id_seed);
 506 #ifdef CONFIG_64BIT
 507         return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
 508 #else
 509         return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
 510 #endif
 511 }
 512 EXPORT_SYMBOL_GPL(nf_ct_get_id);
 513
 514 static void
 515 clean_from_lists(struct nf_conn *ct)
 516 {
 517         pr_debug("clean_from_lists(%p)\n", ct);
 518         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 519         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 520
 521         /* Destroy all pending expectations */
 522         nf_ct_remove_expectations(ct);
 523 }
 524
 525 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
 526
 527 /* Released via nf_ct_destroy() */
 528 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 529                                  const struct nf_conntrack_zone *zone,
 530                                  gfp_t flags)
 531 {
 532         struct nf_conn *tmpl, *p;
 533
 534         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
 535                 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
 536                 if (!tmpl)
 537                         return NULL;
 538
 539                 p = tmpl;
 540                 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 541                 if (tmpl != p) {
 542                         tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 543                         tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
 544                 }
 545         } else {
 546                 tmpl = kzalloc(sizeof(*tmpl), flags);
 547                 if (!tmpl)
 548                         return NULL;
 549         }
 550
 551         tmpl->status = IPS_TEMPLATE;
 552         write_pnet(&tmpl->ct_net, net);
 553         nf_ct_zone_add(tmpl, zone);
 554         refcount_set(&tmpl->ct_general.use, 1);
 555
 556         return tmpl;
 557 }
 558 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
 559
 560 void nf_ct_tmpl_free(struct nf_conn *tmpl)
 561 {
 562         kfree(tmpl->ext);
 563
 564         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
 565                 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
 566         else
 567                 kfree(tmpl);
 568 }
 569 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
 570
 571 static void destroy_gre_conntrack(struct nf_conn *ct)
 572 {
 573 #ifdef CONFIG_NF_CT_PROTO_GRE
 574         struct nf_conn *master = ct->master;
 575
 576         if (master)
 577                 nf_ct_gre_keymap_destroy(master);
 578 #endif
 579 }
 580
 581 void nf_ct_destroy(struct nf_conntrack *nfct)
 582 {
 583         struct nf_conn *ct = (struct nf_conn *)nfct;
 584
 585         pr_debug("%s(%p)\n", __func__, ct);
 586         WARN_ON(refcount_read(&nfct->use) != 0);
 587
 588         if (unlikely(nf_ct_is_template(ct))) {
 589                 nf_ct_tmpl_free(ct);
 590                 return;
 591         }
 592
 593         if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
 594                 destroy_gre_conntrack(ct);
 595
 596         /* Expectations will have been removed in clean_from_lists,
 597          * except TFTP can create an expectation on the first packet,
 598          * before connection is in the list, so we need to clean here,
 599          * too.
 600          */
 601         nf_ct_remove_expectations(ct);
 602
 603         if (ct->master)
 604                 nf_ct_put(ct->master);
 605
 606         pr_debug("%s: returning ct=%p to slab\n", __func__, ct);
 607         nf_conntrack_free(ct);
 608 }
 609 EXPORT_SYMBOL(nf_ct_destroy);
 610
 611 static void __nf_ct_delete_from_lists(struct nf_conn *ct)
 612 {
 613         struct net *net = nf_ct_net(ct);
 614         unsigned int hash, reply_hash;
 615         unsigned int sequence;
 616
 617         do {
 618                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 619                 hash = hash_conntrack(net,
 620                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 621                                       nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL));
 622                 reply_hash = hash_conntrack(net,
 623                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 624                                            nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
 625         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 626
 627         clean_from_lists(ct);
 628         nf_conntrack_double_unlock(hash, reply_hash);
 629 }
 630
 631 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 632 {
 633         nf_ct_helper_destroy(ct);
 634         local_bh_disable();
 635
 636         __nf_ct_delete_from_lists(ct);
 637
 638         local_bh_enable();
 639 }
 640
 641 static void nf_ct_add_to_ecache_list(struct nf_conn *ct)
 642 {
 643 #ifdef CONFIG_NF_CONNTRACK_EVENTS
 644         struct nf_conntrack_net *cnet = nf_ct_pernet(nf_ct_net(ct));
 645
 646         spin_lock(&cnet->ecache.dying_lock);
 647         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 648                                  &cnet->ecache.dying_list);
 649         spin_unlock(&cnet->ecache.dying_lock);
 650 #endif
 651 }
 652
 653 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 654 {
 655         struct nf_conn_tstamp *tstamp;
 656         struct net *net;
 657
 658         if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
 659                 return false;
 660
 661         tstamp = nf_conn_tstamp_find(ct);
 662         if (tstamp) {
 663                 s32 timeout = READ_ONCE(ct->timeout) - nfct_time_stamp;
 664
 665                 tstamp->stop = ktime_get_real_ns();
 666                 if (timeout < 0)
 667                         tstamp->stop -= jiffies_to_nsecs(-timeout);
 668         }
 669
 670         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 671                                     portid, report) < 0) {
 672                 /* destroy event was not delivered. nf_ct_put will
 673                  * be done by event cache worker on redelivery.
 674                  */
 675                 nf_ct_helper_destroy(ct);
 676                 local_bh_disable();
 677                 __nf_ct_delete_from_lists(ct);
 678                 nf_ct_add_to_ecache_list(ct);
 679                 local_bh_enable();
 680
 681                 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL);
 682                 return false;
 683         }
 684
 685         net = nf_ct_net(ct);
 686         if (nf_conntrack_ecache_dwork_pending(net))
 687                 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT);
 688         nf_ct_delete_from_lists(ct);
 689         nf_ct_put(ct);
 690         return true;
 691 }
 692 EXPORT_SYMBOL_GPL(nf_ct_delete);
 693
 694 static inline bool
 695 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 696                 const struct nf_conntrack_tuple *tuple,
 697                 const struct nf_conntrack_zone *zone,
 698                 const struct net *net)
 699 {
 700         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 701
 702         /* A conntrack can be recreated with the equal tuple,
 703          * so we need to check that the conntrack is confirmed
 704          */
 705         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 706                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 707                nf_ct_is_confirmed(ct) &&
 708                net_eq(net, nf_ct_net(ct));
 709 }
 710
 711 static inline bool
 712 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
 713 {
 714         return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 715                                  &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
 716                nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
 717                                  &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
 718                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
 719                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
 720                net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
 721 }
 722
 723 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
 724 static void nf_ct_gc_expired(struct nf_conn *ct)
 725 {
 726         if (!refcount_inc_not_zero(&ct->ct_general.use))
 727                 return;
 728
 729         /* load ->status after refcount increase */
 730         smp_acquire__after_ctrl_dep();
 731
 732         if (nf_ct_should_gc(ct))
 733                 nf_ct_kill(ct);
 734
 735         nf_ct_put(ct);
 736 }
 737
 738 /*
 739  * Warning :
 740  * - Caller must take a reference on returned object
 741  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 742  */
 743 static struct nf_conntrack_tuple_hash *
 744 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 745                       const struct nf_conntrack_tuple *tuple, u32 hash)
 746 {
 747         struct nf_conntrack_tuple_hash *h;
 748         struct hlist_nulls_head *ct_hash;
 749         struct hlist_nulls_node *n;
 750         unsigned int bucket, hsize;
 751
 752 begin:
 753         nf_conntrack_get_ht(&ct_hash, &hsize);
 754         bucket = reciprocal_scale(hash, hsize);
 755
 756         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
 757                 struct nf_conn *ct;
 758
 759                 ct = nf_ct_tuplehash_to_ctrack(h);
 760                 if (nf_ct_is_expired(ct)) {
 761                         nf_ct_gc_expired(ct);
 762                         continue;
 763                 }
 764
 765                 if (nf_ct_key_equal(h, tuple, zone, net))
 766                         return h;
 767         }
 768         /*
 769          * if the nulls value we got at the end of this lookup is
 770          * not the expected one, we must restart lookup.
 771          * We probably met an item that was moved to another chain.
 772          */
 773         if (get_nulls_value(n) != bucket) {
 774                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 775                 goto begin;
 776         }
 777
 778         return NULL;
 779 }
 780
 781 /* Find a connection corresponding to a tuple. */
 782 static struct nf_conntrack_tuple_hash *
 783 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 784                         const struct nf_conntrack_tuple *tuple, u32 hash)
 785 {
 786         struct nf_conntrack_tuple_hash *h;
 787         struct nf_conn *ct;
 788
 789         rcu_read_lock();
 790
 791         h = ____nf_conntrack_find(net, zone, tuple, hash);
 792         if (h) {
 793                 /* We have a candidate that matches the tuple we're interested
 794                  * in, try to obtain a reference and re-check tuple
 795                  */
 796                 ct = nf_ct_tuplehash_to_ctrack(h);
 797                 if (likely(refcount_inc_not_zero(&ct->ct_general.use))) {
 798                         /* re-check key after refcount */
 799                         smp_acquire__after_ctrl_dep();
 800
 801                         if (likely(nf_ct_key_equal(h, tuple, zone, net)))
 802                                 goto found;
 803
 804                         /* TYPESAFE_BY_RCU recycled the candidate */
 805                         nf_ct_put(ct);
 806                 }
 807
 808                 h = NULL;
 809         }
 810 found:
 811         rcu_read_unlock();
 812
 813         return h;
 814 }
 815
 816 struct nf_conntrack_tuple_hash *
 817 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 818                       const struct nf_conntrack_tuple *tuple)
 819 {
 820         unsigned int rid, zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL);
 821         struct nf_conntrack_tuple_hash *thash;
 822
 823         thash = __nf_conntrack_find_get(net, zone, tuple,
 824                                         hash_conntrack_raw(tuple, zone_id, net));
 825
 826         if (thash)
 827                 return thash;
 828
 829         rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY);
 830         if (rid != zone_id)
 831                 return __nf_conntrack_find_get(net, zone, tuple,
 832                                                hash_conntrack_raw(tuple, rid, net));
 833         return thash;
 834 }
 835 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 836
 837 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 838                                        unsigned int hash,
 839                                        unsigned int reply_hash)
 840 {
 841         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 842                            &nf_conntrack_hash[hash]);
 843         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 844                            &nf_conntrack_hash[reply_hash]);
 845 }
 846
 847 static bool nf_ct_ext_valid_pre(const struct nf_ct_ext *ext)
 848 {
 849         /* if ext->gen_id is not equal to nf_conntrack_ext_genid, some extensions
 850          * may contain stale pointers to e.g. helper that has been removed.
 851          *
 852          * The helper can't clear this because the nf_conn object isn't in
 853          * any hash and synchronize_rcu() isn't enough because associated skb
 854          * might sit in a queue.
 855          */
 856         return !ext || ext->gen_id == atomic_read(&nf_conntrack_ext_genid);
 857 }
 858
 859 static bool nf_ct_ext_valid_post(struct nf_ct_ext *ext)
 860 {
 861         if (!ext)
 862                 return true;
 863
 864         if (ext->gen_id != atomic_read(&nf_conntrack_ext_genid))
 865                 return false;
 866
 867         /* inserted into conntrack table, nf_ct_iterate_cleanup()
 868          * will find it.  Disable nf_ct_ext_find() id check.
 869          */
 870         WRITE_ONCE(ext->gen_id, 0);
 871         return true;
 872 }
 873
 874 int
 875 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 876 {
 877         const struct nf_conntrack_zone *zone;
 878         struct net *net = nf_ct_net(ct);
 879         unsigned int hash, reply_hash;
 880         struct nf_conntrack_tuple_hash *h;
 881         struct hlist_nulls_node *n;
 882         unsigned int max_chainlen;
 883         unsigned int chainlen = 0;
 884         unsigned int sequence;
 885         int err = -EEXIST;
 886
 887         zone = nf_ct_zone(ct);
 888
 889         if (!nf_ct_ext_valid_pre(ct->ext)) {
 890                 NF_CT_STAT_INC_ATOMIC(net, insert_failed);
 891                 return -ETIMEDOUT;
 892         }
 893
 894         local_bh_disable();
 895         do {
 896                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 897                 hash = hash_conntrack(net,
 898                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 899                                       nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_ORIGINAL));
 900                 reply_hash = hash_conntrack(net,
 901                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 902                                            nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
 903         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 904
 905         max_chainlen = MIN_CHAINLEN + get_random_u32_below(MAX_CHAINLEN);
 906
 907         /* See if there's one in the list already, including reverse */
 908         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) {
 909                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 910                                     zone, net))
 911                         goto out;
 912
 913                 if (chainlen++ > max_chainlen)
 914                         goto chaintoolong;
 915         }
 916
 917         chainlen = 0;
 918
 919         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) {
 920                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 921                                     zone, net))
 922                         goto out;
 923                 if (chainlen++ > max_chainlen)
 924                         goto chaintoolong;
 925         }
 926
 927         smp_wmb();
 928         /* The caller holds a reference to this object */
 929         refcount_set(&ct->ct_general.use, 2);
 930         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 931         nf_conntrack_double_unlock(hash, reply_hash);
 932         NF_CT_STAT_INC(net, insert);
 933         local_bh_enable();
 934
 935         if (!nf_ct_ext_valid_post(ct->ext)) {
 936                 nf_ct_kill(ct);
 937                 NF_CT_STAT_INC_ATOMIC(net, drop);
 938                 return -ETIMEDOUT;
 939         }
 940
 941         return 0;
 942 chaintoolong:
 943         NF_CT_STAT_INC(net, chaintoolong);
 944         err = -ENOSPC;
 945 out:
 946         nf_conntrack_double_unlock(hash, reply_hash);
 947         local_bh_enable();
 948         return err;
 949 }
 950 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 951
 952 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
 953                     unsigned int bytes)
 954 {
 955         struct nf_conn_acct *acct;
 956
 957         acct = nf_conn_acct_find(ct);
 958         if (acct) {
 959                 struct nf_conn_counter *counter = acct->counter;
 960
 961                 atomic64_add(packets, &counter[dir].packets);
 962                 atomic64_add(bytes, &counter[dir].bytes);
 963         }
 964 }
 965 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
 966
 967 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 968                              const struct nf_conn *loser_ct)
 969 {
 970         struct nf_conn_acct *acct;
 971
 972         acct = nf_conn_acct_find(loser_ct);
 973         if (acct) {
 974                 struct nf_conn_counter *counter = acct->counter;
 975                 unsigned int bytes;
 976
 977                 /* u32 should be fine since we must have seen one packet. */
 978                 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
 979                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
 980         }
 981 }
 982
 983 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
 984 {
 985         struct nf_conn_tstamp *tstamp;
 986
 987         refcount_inc(&ct->ct_general.use);
 988
 989         /* set conntrack timestamp, if enabled. */
 990         tstamp = nf_conn_tstamp_find(ct);
 991         if (tstamp)
 992                 tstamp->start = ktime_get_real_ns();
 993 }
 994
 995 /* caller must hold locks to prevent concurrent changes */
 996 static int __nf_ct_resolve_clash(struct sk_buff *skb,
 997                                  struct nf_conntrack_tuple_hash *h)
 998 {
 999         /* This is the conntrack entry already in hashes that won race. */
1000         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1001         enum ip_conntrack_info ctinfo;
1002         struct nf_conn *loser_ct;
1003
1004         loser_ct = nf_ct_get(skb, &ctinfo);
1005
1006         if (nf_ct_is_dying(ct))
1007                 return NF_DROP;
1008
1009         if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
1010             nf_ct_match(ct, loser_ct)) {
1011                 struct net *net = nf_ct_net(ct);
1012
1013                 nf_conntrack_get(&ct->ct_general);
1014
1015                 nf_ct_acct_merge(ct, ctinfo, loser_ct);
1016                 nf_ct_put(loser_ct);
1017                 nf_ct_set(skb, ct, ctinfo);
1018
1019                 NF_CT_STAT_INC(net, clash_resolve);
1020                 return NF_ACCEPT;
1021         }
1022
1023         return NF_DROP;
1024 }
1025
1026 /**
1027  * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
1028  *
1029  * @skb: skb that causes the collision
1030  * @repl_idx: hash slot for reply direction
1031  *
1032  * Called when origin or reply direction had a clash.
1033  * The skb can be handled without packet drop provided the reply direction
1034  * is unique or there the existing entry has the identical tuple in both
1035  * directions.
1036  *
1037  * Caller must hold conntrack table locks to prevent concurrent updates.
1038  *
1039  * Returns NF_DROP if the clash could not be handled.
1040  */
1041 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
1042 {
1043         struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
1044         const struct nf_conntrack_zone *zone;
1045         struct nf_conntrack_tuple_hash *h;
1046         struct hlist_nulls_node *n;
1047         struct net *net;
1048
1049         zone = nf_ct_zone(loser_ct);
1050         net = nf_ct_net(loser_ct);
1051
1052         /* Reply direction must never result in a clash, unless both origin
1053          * and reply tuples are identical.
1054          */
1055         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
1056                 if (nf_ct_key_equal(h,
1057                                     &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1058                                     zone, net))
1059                         return __nf_ct_resolve_clash(skb, h);
1060         }
1061
1062         /* We want the clashing entry to go away real soon: 1 second timeout. */
1063         WRITE_ONCE(loser_ct->timeout, nfct_time_stamp + HZ);
1064
1065         /* IPS_NAT_CLASH removes the entry automatically on the first
1066          * reply.  Also prevents UDP tracker from moving the entry to
1067          * ASSURED state, i.e. the entry can always be evicted under
1068          * pressure.
1069          */
1070         loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
1071
1072         __nf_conntrack_insert_prepare(loser_ct);
1073
1074         /* fake add for ORIGINAL dir: we want lookups to only find the entry
1075          * already in the table.  This also hides the clashing entry from
1076          * ctnetlink iteration, i.e. conntrack -L won't show them.
1077          */
1078         hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
1079
1080         hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
1081                                  &nf_conntrack_hash[repl_idx]);
1082
1083         NF_CT_STAT_INC(net, clash_resolve);
1084         return NF_ACCEPT;
1085 }
1086
1087 /**
1088  * nf_ct_resolve_clash - attempt to handle clash without packet drop
1089  *
1090  * @skb: skb that causes the clash
1091  * @h: tuplehash of the clashing entry already in table
1092  * @reply_hash: hash slot for reply direction
1093  *
1094  * A conntrack entry can be inserted to the connection tracking table
1095  * if there is no existing entry with an identical tuple.
1096  *
1097  * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1098  * to be dropped.  In case @skb is retransmitted, next conntrack lookup
1099  * will find the already-existing entry.
1100  *
1101  * The major problem with such packet drop is the extra delay added by
1102  * the packet loss -- it will take some time for a retransmit to occur
1103  * (or the sender to time out when waiting for a reply).
1104  *
1105  * This function attempts to handle the situation without packet drop.
1106  *
1107  * If @skb has no NAT transformation or if the colliding entries are
1108  * exactly the same, only the to-be-confirmed conntrack entry is discarded
1109  * and @skb is associated with the conntrack entry already in the table.
1110  *
1111  * Failing that, the new, unconfirmed conntrack is still added to the table
1112  * provided that the collision only occurs in the ORIGINAL direction.
1113  * The new entry will be added only in the non-clashing REPLY direction,
1114  * so packets in the ORIGINAL direction will continue to match the existing
1115  * entry.  The new entry will also have a fixed timeout so it expires --
1116  * due to the collision, it will only see reply traffic.
1117  *
1118  * Returns NF_DROP if the clash could not be resolved.
1119  */
1120 static __cold noinline int
1121 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1122                     u32 reply_hash)
1123 {
1124         /* This is the conntrack entry already in hashes that won race. */
1125         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1126         const struct nf_conntrack_l4proto *l4proto;
1127         enum ip_conntrack_info ctinfo;
1128         struct nf_conn *loser_ct;
1129         struct net *net;
1130         int ret;
1131
1132         loser_ct = nf_ct_get(skb, &ctinfo);
1133         net = nf_ct_net(loser_ct);
1134
1135         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1136         if (!l4proto->allow_clash)
1137                 goto drop;
1138
1139         ret = __nf_ct_resolve_clash(skb, h);
1140         if (ret == NF_ACCEPT)
1141                 return ret;
1142
1143         ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1144         if (ret == NF_ACCEPT)
1145                 return ret;
1146
1147 drop:
1148         NF_CT_STAT_INC(net, drop);
1149         NF_CT_STAT_INC(net, insert_failed);
1150         return NF_DROP;
1151 }
1152
1153 /* Confirm a connection given skb; places it in hash table */
1154 int
1155 __nf_conntrack_confirm(struct sk_buff *skb)
1156 {
1157         unsigned int chainlen = 0, sequence, max_chainlen;
1158         const struct nf_conntrack_zone *zone;
1159         unsigned int hash, reply_hash;
1160         struct nf_conntrack_tuple_hash *h;
1161         struct nf_conn *ct;
1162         struct nf_conn_help *help;
1163         struct hlist_nulls_node *n;
1164         enum ip_conntrack_info ctinfo;
1165         struct net *net;
1166         int ret = NF_DROP;
1167
1168         ct = nf_ct_get(skb, &ctinfo);
1169         net = nf_ct_net(ct);
1170
1171         /* ipt_REJECT uses nf_conntrack_attach to attach related
1172            ICMP/TCP RST packets in other direction.  Actual packet
1173            which created connection will be IP_CT_NEW or for an
1174            expected connection, IP_CT_RELATED. */
1175         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1176                 return NF_ACCEPT;
1177
1178         zone = nf_ct_zone(ct);
1179         local_bh_disable();
1180
1181         do {
1182                 sequence = read_seqcount_begin(&nf_conntrack_generation);
1183                 /* reuse the hash saved before */
1184                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1185                 hash = scale_hash(hash);
1186                 reply_hash = hash_conntrack(net,
1187                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1188                                            nf_ct_zone_id(nf_ct_zone(ct), IP_CT_DIR_REPLY));
1189         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1190
1191         /* We're not in hash table, and we refuse to set up related
1192          * connections for unconfirmed conns.  But packet copies and
1193          * REJECT will give spurious warnings here.
1194          */
1195
1196         /* Another skb with the same unconfirmed conntrack may
1197          * win the race. This may happen for bridge(br_flood)
1198          * or broadcast/multicast packets do skb_clone with
1199          * unconfirmed conntrack.
1200          */
1201         if (unlikely(nf_ct_is_confirmed(ct))) {
1202                 WARN_ON_ONCE(1);
1203                 nf_conntrack_double_unlock(hash, reply_hash);
1204                 local_bh_enable();
1205                 return NF_DROP;
1206         }
1207
1208         if (!nf_ct_ext_valid_pre(ct->ext)) {
1209                 NF_CT_STAT_INC(net, insert_failed);
1210                 goto dying;
1211         }
1212
1213         pr_debug("Confirming conntrack %p\n", ct);
1214         /* We have to check the DYING flag after unlink to prevent
1215          * a race against nf_ct_get_next_corpse() possibly called from
1216          * user context, else we insert an already 'dead' hash, blocking
1217          * further use of that particular connection -JM.
1218          */
1219         ct->status |= IPS_CONFIRMED;
1220
1221         if (unlikely(nf_ct_is_dying(ct))) {
1222                 NF_CT_STAT_INC(net, insert_failed);
1223                 goto dying;
1224         }
1225
1226         max_chainlen = MIN_CHAINLEN + get_random_u32_below(MAX_CHAINLEN);
1227         /* See if there's one in the list already, including reverse:
1228            NAT could have grabbed it without realizing, since we're
1229            not in the hash.  If there is, we lost race. */
1230         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode) {
1231                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1232                                     zone, net))
1233                         goto out;
1234                 if (chainlen++ > max_chainlen)
1235                         goto chaintoolong;
1236         }
1237
1238         chainlen = 0;
1239         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode) {
1240                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1241                                     zone, net))
1242                         goto out;
1243                 if (chainlen++ > max_chainlen) {
1244 chaintoolong:
1245                         NF_CT_STAT_INC(net, chaintoolong);
1246                         NF_CT_STAT_INC(net, insert_failed);
1247                         ret = NF_DROP;
1248                         goto dying;
1249                 }
1250         }
1251
1252         /* Timer relative to confirmation time, not original
1253            setting time, otherwise we'd get timer wrap in
1254            weird delay cases. */
1255         ct->timeout += nfct_time_stamp;
1256
1257         __nf_conntrack_insert_prepare(ct);
1258
1259         /* Since the lookup is lockless, hash insertion must be done after
1260          * starting the timer and setting the CONFIRMED bit. The RCU barriers
1261          * guarantee that no other CPU can find the conntrack before the above
1262          * stores are visible.
1263          */
1264         __nf_conntrack_hash_insert(ct, hash, reply_hash);
1265         nf_conntrack_double_unlock(hash, reply_hash);
1266         local_bh_enable();
1267
1268         /* ext area is still valid (rcu read lock is held,
1269          * but will go out of scope soon, we need to remove
1270          * this conntrack again.
1271          */
1272         if (!nf_ct_ext_valid_post(ct->ext)) {
1273                 nf_ct_kill(ct);
1274                 NF_CT_STAT_INC_ATOMIC(net, drop);
1275                 return NF_DROP;
1276         }
1277
1278         help = nfct_help(ct);
1279         if (help && help->helper)
1280                 nf_conntrack_event_cache(IPCT_HELPER, ct);
1281
1282         nf_conntrack_event_cache(master_ct(ct) ?
1283                                  IPCT_RELATED : IPCT_NEW, ct);
1284         return NF_ACCEPT;
1285
1286 out:
1287         ret = nf_ct_resolve_clash(skb, h, reply_hash);
1288 dying:
1289         nf_conntrack_double_unlock(hash, reply_hash);
1290         local_bh_enable();
1291         return ret;
1292 }
1293 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1294
1295 /* Returns true if a connection correspondings to the tuple (required
1296    for NAT). */
1297 int
1298 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1299                          const struct nf_conn *ignored_conntrack)
1300 {
1301         struct net *net = nf_ct_net(ignored_conntrack);
1302         const struct nf_conntrack_zone *zone;
1303         struct nf_conntrack_tuple_hash *h;
1304         struct hlist_nulls_head *ct_hash;
1305         unsigned int hash, hsize;
1306         struct hlist_nulls_node *n;
1307         struct nf_conn *ct;
1308
1309         zone = nf_ct_zone(ignored_conntrack);
1310
1311         rcu_read_lock();
1312  begin:
1313         nf_conntrack_get_ht(&ct_hash, &hsize);
1314         hash = __hash_conntrack(net, tuple, nf_ct_zone_id(zone, IP_CT_DIR_REPLY), hsize);
1315
1316         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1317                 ct = nf_ct_tuplehash_to_ctrack(h);
1318
1319                 if (ct == ignored_conntrack)
1320                         continue;
1321
1322                 if (nf_ct_is_expired(ct)) {
1323                         nf_ct_gc_expired(ct);
1324                         continue;
1325                 }
1326
1327                 if (nf_ct_key_equal(h, tuple, zone, net)) {
1328                         /* Tuple is taken already, so caller will need to find
1329                          * a new source port to use.
1330                          *
1331                          * Only exception:
1332                          * If the *original tuples* are identical, then both
1333                          * conntracks refer to the same flow.
1334                          * This is a rare situation, it can occur e.g. when
1335                          * more than one UDP packet is sent from same socket
1336                          * in different threads.
1337                          *
1338                          * Let nf_ct_resolve_clash() deal with this later.
1339                          */
1340                         if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1341                                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
1342                                               nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
1343                                 continue;
1344
1345                         NF_CT_STAT_INC_ATOMIC(net, found);
1346                         rcu_read_unlock();
1347                         return 1;
1348                 }
1349         }
1350
1351         if (get_nulls_value(n) != hash) {
1352                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1353                 goto begin;
1354         }
1355
1356         rcu_read_unlock();
1357
1358         return 0;
1359 }
1360 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1361
1362 #define NF_CT_EVICTION_RANGE    8
1363
1364 /* There's a small race here where we may free a just-assured
1365    connection.  Too bad: we're in trouble anyway. */
1366 static unsigned int early_drop_list(struct net *net,
1367                                     struct hlist_nulls_head *head)
1368 {
1369         struct nf_conntrack_tuple_hash *h;
1370         struct hlist_nulls_node *n;
1371         unsigned int drops = 0;
1372         struct nf_conn *tmp;
1373
1374         hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1375                 tmp = nf_ct_tuplehash_to_ctrack(h);
1376
1377                 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1378                         continue;
1379
1380                 if (nf_ct_is_expired(tmp)) {
1381                         nf_ct_gc_expired(tmp);
1382                         continue;
1383                 }
1384
1385                 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1386                     !net_eq(nf_ct_net(tmp), net) ||
1387                     nf_ct_is_dying(tmp))
1388                         continue;
1389
1390                 if (!refcount_inc_not_zero(&tmp->ct_general.use))
1391                         continue;
1392
1393                 /* load ->ct_net and ->status after refcount increase */
1394                 smp_acquire__after_ctrl_dep();
1395
1396                 /* kill only if still in same netns -- might have moved due to
1397                  * SLAB_TYPESAFE_BY_RCU rules.
1398                  *
1399                  * We steal the timer reference.  If that fails timer has
1400                  * already fired or someone else deleted it. Just drop ref
1401                  * and move to next entry.
1402                  */
1403                 if (net_eq(nf_ct_net(tmp), net) &&
1404                     nf_ct_is_confirmed(tmp) &&
1405                     nf_ct_delete(tmp, 0, 0))
1406                         drops++;
1407
1408                 nf_ct_put(tmp);
1409         }
1410
1411         return drops;
1412 }
1413
1414 static noinline int early_drop(struct net *net, unsigned int hash)
1415 {
1416         unsigned int i, bucket;
1417
1418         for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1419                 struct hlist_nulls_head *ct_hash;
1420                 unsigned int hsize, drops;
1421
1422                 rcu_read_lock();
1423                 nf_conntrack_get_ht(&ct_hash, &hsize);
1424                 if (!i)
1425                         bucket = reciprocal_scale(hash, hsize);
1426                 else
1427                         bucket = (bucket + 1) % hsize;
1428
1429                 drops = early_drop_list(net, &ct_hash[bucket]);
1430                 rcu_read_unlock();
1431
1432                 if (drops) {
1433                         NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1434                         return true;
1435                 }
1436         }
1437
1438         return false;
1439 }
1440
1441 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1442 {
1443         return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1444 }
1445
1446 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1447 {
1448         const struct nf_conntrack_l4proto *l4proto;
1449
1450         if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1451                 return true;
1452
1453         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1454         if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1455                 return true;
1456
1457         return false;
1458 }
1459
1460 static void gc_worker(struct work_struct *work)
1461 {
1462         unsigned int i, hashsz, nf_conntrack_max95 = 0;
1463         u32 end_time, start_time = nfct_time_stamp;
1464         struct conntrack_gc_work *gc_work;
1465         unsigned int expired_count = 0;
1466         unsigned long next_run;
1467         s32 delta_time;
1468         long count;
1469
1470         gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1471
1472         i = gc_work->next_bucket;
1473         if (gc_work->early_drop)
1474                 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1475
1476         if (i == 0) {
1477                 gc_work->avg_timeout = GC_SCAN_INTERVAL_INIT;
1478                 gc_work->count = GC_SCAN_INITIAL_COUNT;
1479                 gc_work->start_time = start_time;
1480         }
1481
1482         next_run = gc_work->avg_timeout;
1483         count = gc_work->count;
1484
1485         end_time = start_time + GC_SCAN_MAX_DURATION;
1486
1487         do {
1488                 struct nf_conntrack_tuple_hash *h;
1489                 struct hlist_nulls_head *ct_hash;
1490                 struct hlist_nulls_node *n;
1491                 struct nf_conn *tmp;
1492
1493                 rcu_read_lock();
1494
1495                 nf_conntrack_get_ht(&ct_hash, &hashsz);
1496                 if (i >= hashsz) {
1497                         rcu_read_unlock();
1498                         break;
1499                 }
1500
1501                 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1502                         struct nf_conntrack_net *cnet;
1503                         struct net *net;
1504                         long expires;
1505
1506                         tmp = nf_ct_tuplehash_to_ctrack(h);
1507
1508                         if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1509                                 nf_ct_offload_timeout(tmp);
1510                                 continue;
1511                         }
1512
1513                         if (expired_count > GC_SCAN_EXPIRED_MAX) {
1514                                 rcu_read_unlock();
1515
1516                                 gc_work->next_bucket = i;
1517                                 gc_work->avg_timeout = next_run;
1518                                 gc_work->count = count;
1519
1520                                 delta_time = nfct_time_stamp - gc_work->start_time;
1521
1522                                 /* re-sched immediately if total cycle time is exceeded */
1523                                 next_run = delta_time < (s32)GC_SCAN_INTERVAL_MAX;
1524                                 goto early_exit;
1525                         }
1526
1527                         if (nf_ct_is_expired(tmp)) {
1528                                 nf_ct_gc_expired(tmp);
1529                                 expired_count++;
1530                                 continue;
1531                         }
1532
1533                         expires = clamp(nf_ct_expires(tmp), GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_CLAMP);
1534                         expires = (expires - (long)next_run) / ++count;
1535                         next_run += expires;
1536
1537                         if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1538                                 continue;
1539
1540                         net = nf_ct_net(tmp);
1541                         cnet = nf_ct_pernet(net);
1542                         if (atomic_read(&cnet->count) < nf_conntrack_max95)
1543                                 continue;
1544
1545                         /* need to take reference to avoid possible races */
1546                         if (!refcount_inc_not_zero(&tmp->ct_general.use))
1547                                 continue;
1548
1549                         /* load ->status after refcount increase */
1550                         smp_acquire__after_ctrl_dep();
1551
1552                         if (gc_worker_skip_ct(tmp)) {
1553                                 nf_ct_put(tmp);
1554                                 continue;
1555                         }
1556
1557                         if (gc_worker_can_early_drop(tmp)) {
1558                                 nf_ct_kill(tmp);
1559                                 expired_count++;
1560                         }
1561
1562                         nf_ct_put(tmp);
1563                 }
1564
1565                 /* could check get_nulls_value() here and restart if ct
1566                  * was moved to another chain.  But given gc is best-effort
1567                  * we will just continue with next hash slot.
1568                  */
1569                 rcu_read_unlock();
1570                 cond_resched();
1571                 i++;
1572
1573                 delta_time = nfct_time_stamp - end_time;
1574                 if (delta_time > 0 && i < hashsz) {
1575                         gc_work->avg_timeout = next_run;
1576                         gc_work->count = count;
1577                         gc_work->next_bucket = i;
1578                         next_run = 0;
1579                         goto early_exit;
1580                 }
1581         } while (i < hashsz);
1582
1583         gc_work->next_bucket = 0;
1584
1585         next_run = clamp(next_run, GC_SCAN_INTERVAL_MIN, GC_SCAN_INTERVAL_MAX);
1586
1587         delta_time = max_t(s32, nfct_time_stamp - gc_work->start_time, 1);
1588         if (next_run > (unsigned long)delta_time)
1589                 next_run -= delta_time;
1590         else
1591                 next_run = 1;
1592
1593 early_exit:
1594         if (gc_work->exiting)
1595                 return;
1596
1597         if (next_run)
1598                 gc_work->early_drop = false;
1599
1600         queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1601 }
1602
1603 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1604 {
1605         INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
1606         gc_work->exiting = false;
1607 }
1608
1609 static struct nf_conn *
1610 __nf_conntrack_alloc(struct net *net,
1611                      const struct nf_conntrack_zone *zone,
1612                      const struct nf_conntrack_tuple *orig,
1613                      const struct nf_conntrack_tuple *repl,
1614                      gfp_t gfp, u32 hash)
1615 {
1616         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
1617         unsigned int ct_count;
1618         struct nf_conn *ct;
1619
1620         /* We don't want any race condition at early drop stage */
1621         ct_count = atomic_inc_return(&cnet->count);
1622
1623         if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) {
1624                 if (!early_drop(net, hash)) {
1625                         if (!conntrack_gc_work.early_drop)
1626                                 conntrack_gc_work.early_drop = true;
1627                         atomic_dec(&cnet->count);
1628                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1629                         return ERR_PTR(-ENOMEM);
1630                 }
1631         }
1632
1633         /*
1634          * Do not use kmem_cache_zalloc(), as this cache uses
1635          * SLAB_TYPESAFE_BY_RCU.
1636          */
1637         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1638         if (ct == NULL)
1639                 goto out;
1640
1641         spin_lock_init(&ct->lock);
1642         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1643         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1644         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1645         /* save hash for reusing when confirming */
1646         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1647         ct->status = 0;
1648         WRITE_ONCE(ct->timeout, 0);
1649         write_pnet(&ct->ct_net, net);
1650         memset_after(ct, 0, __nfct_init_offset);
1651
1652         nf_ct_zone_add(ct, zone);
1653
1654         /* Because we use RCU lookups, we set ct_general.use to zero before
1655          * this is inserted in any list.
1656          */
1657         refcount_set(&ct->ct_general.use, 0);
1658         return ct;
1659 out:
1660         atomic_dec(&cnet->count);
1661         return ERR_PTR(-ENOMEM);
1662 }
1663
1664 struct nf_conn *nf_conntrack_alloc(struct net *net,
1665                                    const struct nf_conntrack_zone *zone,
1666                                    const struct nf_conntrack_tuple *orig,
1667                                    const struct nf_conntrack_tuple *repl,
1668                                    gfp_t gfp)
1669 {
1670         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1671 }
1672 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1673
1674 void nf_conntrack_free(struct nf_conn *ct)
1675 {
1676         struct net *net = nf_ct_net(ct);
1677         struct nf_conntrack_net *cnet;
1678
1679         /* A freed object has refcnt == 0, that's
1680          * the golden rule for SLAB_TYPESAFE_BY_RCU
1681          */
1682         WARN_ON(refcount_read(&ct->ct_general.use) != 0);
1683
1684         if (ct->status & IPS_SRC_NAT_DONE) {
1685                 const struct nf_nat_hook *nat_hook;
1686
1687                 rcu_read_lock();
1688                 nat_hook = rcu_dereference(nf_nat_hook);
1689                 if (nat_hook)
1690                         nat_hook->remove_nat_bysrc(ct);
1691                 rcu_read_unlock();
1692         }
1693
1694         kfree(ct->ext);
1695         kmem_cache_free(nf_conntrack_cachep, ct);
1696         cnet = nf_ct_pernet(net);
1697
1698         smp_mb__before_atomic();
1699         atomic_dec(&cnet->count);
1700 }
1701 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1702
1703
1704 /* Allocate a new conntrack: we return -ENOMEM if classification
1705    failed due to stress.  Otherwise it really is unclassifiable. */
1706 static noinline struct nf_conntrack_tuple_hash *
1707 init_conntrack(struct net *net, struct nf_conn *tmpl,
1708                const struct nf_conntrack_tuple *tuple,
1709                struct sk_buff *skb,
1710                unsigned int dataoff, u32 hash)
1711 {
1712         struct nf_conn *ct;
1713         struct nf_conn_help *help;
1714         struct nf_conntrack_tuple repl_tuple;
1715 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1716         struct nf_conntrack_ecache *ecache;
1717 #endif
1718         struct nf_conntrack_expect *exp = NULL;
1719         const struct nf_conntrack_zone *zone;
1720         struct nf_conn_timeout *timeout_ext;
1721         struct nf_conntrack_zone tmp;
1722         struct nf_conntrack_net *cnet;
1723
1724         if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1725                 pr_debug("Can't invert tuple.\n");
1726                 return NULL;
1727         }
1728
1729         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1730         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1731                                   hash);
1732         if (IS_ERR(ct))
1733                 return (struct nf_conntrack_tuple_hash *)ct;
1734
1735         if (!nf_ct_add_synproxy(ct, tmpl)) {
1736                 nf_conntrack_free(ct);
1737                 return ERR_PTR(-ENOMEM);
1738         }
1739
1740         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1741
1742         if (timeout_ext)
1743                 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1744                                       GFP_ATOMIC);
1745
1746         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1747         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1748         nf_ct_labels_ext_add(ct);
1749
1750 #ifdef CONFIG_NF_CONNTRACK_EVENTS
1751         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1752
1753         if ((ecache || net->ct.sysctl_events) &&
1754             !nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1755                                   ecache ? ecache->expmask : 0,
1756                                   GFP_ATOMIC)) {
1757                 nf_conntrack_free(ct);
1758                 return ERR_PTR(-ENOMEM);
1759         }
1760 #endif
1761
1762         cnet = nf_ct_pernet(net);
1763         if (cnet->expect_count) {
1764                 spin_lock_bh(&nf_conntrack_expect_lock);
1765                 exp = nf_ct_find_expectation(net, zone, tuple);
1766                 if (exp) {
1767                         pr_debug("expectation arrives ct=%p exp=%p\n",
1768                                  ct, exp);
1769                         /* Welcome, Mr. Bond.  We've been expecting you... */
1770                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
1771                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1772                         ct->master = exp->master;
1773                         if (exp->helper) {
1774                                 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1775                                 if (help)
1776                                         rcu_assign_pointer(help->helper, exp->helper);
1777                         }
1778
1779 #ifdef CONFIG_NF_CONNTRACK_MARK
1780                         ct->mark = READ_ONCE(exp->master->mark);
1781 #endif
1782 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1783                         ct->secmark = exp->master->secmark;
1784 #endif
1785                         NF_CT_STAT_INC(net, expect_new);
1786                 }
1787                 spin_unlock_bh(&nf_conntrack_expect_lock);
1788         }
1789         if (!exp && tmpl)
1790                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1791
1792         /* Other CPU might have obtained a pointer to this object before it was
1793          * released.  Because refcount is 0, refcount_inc_not_zero() will fail.
1794          *
1795          * After refcount_set(1) it will succeed; ensure that zeroing of
1796          * ct->status and the correct ct->net pointer are visible; else other
1797          * core might observe CONFIRMED bit which means the entry is valid and
1798          * in the hash table, but its not (anymore).
1799          */
1800         smp_wmb();
1801
1802         /* Now it is going to be associated with an sk_buff, set refcount to 1. */
1803         refcount_set(&ct->ct_general.use, 1);
1804
1805         if (exp) {
1806                 if (exp->expectfn)
1807                         exp->expectfn(ct, exp);
1808                 nf_ct_expect_put(exp);
1809         }
1810
1811         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1812 }
1813
1814 /* On success, returns 0, sets skb->_nfct | ctinfo */
1815 static int
1816 resolve_normal_ct(struct nf_conn *tmpl,
1817                   struct sk_buff *skb,
1818                   unsigned int dataoff,
1819                   u_int8_t protonum,
1820                   const struct nf_hook_state *state)
1821 {
1822         const struct nf_conntrack_zone *zone;
1823         struct nf_conntrack_tuple tuple;
1824         struct nf_conntrack_tuple_hash *h;
1825         enum ip_conntrack_info ctinfo;
1826         struct nf_conntrack_zone tmp;
1827         u32 hash, zone_id, rid;
1828         struct nf_conn *ct;
1829
1830         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1831                              dataoff, state->pf, protonum, state->net,
1832                              &tuple)) {
1833                 pr_debug("Can't get tuple\n");
1834                 return 0;
1835         }
1836
1837         /* look for tuple match */
1838         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1839
1840         zone_id = nf_ct_zone_id(zone, IP_CT_DIR_ORIGINAL);
1841         hash = hash_conntrack_raw(&tuple, zone_id, state->net);
1842         h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1843
1844         if (!h) {
1845                 rid = nf_ct_zone_id(zone, IP_CT_DIR_REPLY);
1846                 if (zone_id != rid) {
1847                         u32 tmp = hash_conntrack_raw(&tuple, rid, state->net);
1848
1849                         h = __nf_conntrack_find_get(state->net, zone, &tuple, tmp);
1850                 }
1851         }
1852
1853         if (!h) {
1854                 h = init_conntrack(state->net, tmpl, &tuple,
1855                                    skb, dataoff, hash);
1856                 if (!h)
1857                         return 0;
1858                 if (IS_ERR(h))
1859                         return PTR_ERR(h);
1860         }
1861         ct = nf_ct_tuplehash_to_ctrack(h);
1862
1863         /* It exists; we have (non-exclusive) reference. */
1864         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1865                 ctinfo = IP_CT_ESTABLISHED_REPLY;
1866         } else {
1867                 /* Once we've had two way comms, always ESTABLISHED. */
1868                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1869                         pr_debug("normal packet for %p\n", ct);
1870                         ctinfo = IP_CT_ESTABLISHED;
1871                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1872                         pr_debug("related packet for %p\n", ct);
1873                         ctinfo = IP_CT_RELATED;
1874                 } else {
1875                         pr_debug("new packet for %p\n", ct);
1876                         ctinfo = IP_CT_NEW;
1877                 }
1878         }
1879         nf_ct_set(skb, ct, ctinfo);
1880         return 0;
1881 }
1882
1883 /*
1884  * icmp packets need special treatment to handle error messages that are
1885  * related to a connection.
1886  *
1887  * Callers need to check if skb has a conntrack assigned when this
1888  * helper returns; in such case skb belongs to an already known connection.
1889  */
1890 static unsigned int __cold
1891 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1892                          struct sk_buff *skb,
1893                          unsigned int dataoff,
1894                          u8 protonum,
1895                          const struct nf_hook_state *state)
1896 {
1897         int ret;
1898
1899         if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1900                 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1901 #if IS_ENABLED(CONFIG_IPV6)
1902         else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1903                 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1904 #endif
1905         else
1906                 return NF_ACCEPT;
1907
1908         if (ret <= 0)
1909                 NF_CT_STAT_INC_ATOMIC(state->net, error);
1910
1911         return ret;
1912 }
1913
1914 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1915                           enum ip_conntrack_info ctinfo)
1916 {
1917         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1918
1919         if (!timeout)
1920                 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1921
1922         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1923         return NF_ACCEPT;
1924 }
1925
1926 /* Returns verdict for packet, or -1 for invalid. */
1927 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1928                                       struct sk_buff *skb,
1929                                       unsigned int dataoff,
1930                                       enum ip_conntrack_info ctinfo,
1931                                       const struct nf_hook_state *state)
1932 {
1933         switch (nf_ct_protonum(ct)) {
1934         case IPPROTO_TCP:
1935                 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1936                                                ctinfo, state);
1937         case IPPROTO_UDP:
1938                 return nf_conntrack_udp_packet(ct, skb, dataoff,
1939                                                ctinfo, state);
1940         case IPPROTO_ICMP:
1941                 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1942 #if IS_ENABLED(CONFIG_IPV6)
1943         case IPPROTO_ICMPV6:
1944                 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1945 #endif
1946 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1947         case IPPROTO_UDPLITE:
1948                 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1949                                                    ctinfo, state);
1950 #endif
1951 #ifdef CONFIG_NF_CT_PROTO_SCTP
1952         case IPPROTO_SCTP:
1953                 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1954                                                 ctinfo, state);
1955 #endif
1956 #ifdef CONFIG_NF_CT_PROTO_DCCP
1957         case IPPROTO_DCCP:
1958                 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1959                                                 ctinfo, state);
1960 #endif
1961 #ifdef CONFIG_NF_CT_PROTO_GRE
1962         case IPPROTO_GRE:
1963                 return nf_conntrack_gre_packet(ct, skb, dataoff,
1964                                                ctinfo, state);
1965 #endif
1966         }
1967
1968         return generic_packet(ct, skb, ctinfo);
1969 }
1970
1971 unsigned int
1972 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1973 {
1974         enum ip_conntrack_info ctinfo;
1975         struct nf_conn *ct, *tmpl;
1976         u_int8_t protonum;
1977         int dataoff, ret;
1978
1979         tmpl = nf_ct_get(skb, &ctinfo);
1980         if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1981                 /* Previously seen (loopback or untracked)?  Ignore. */
1982                 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1983                      ctinfo == IP_CT_UNTRACKED)
1984                         return NF_ACCEPT;
1985                 skb->_nfct = 0;
1986         }
1987
1988         /* rcu_read_lock()ed by nf_hook_thresh */
1989         dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1990         if (dataoff <= 0) {
1991                 pr_debug("not prepared to track yet or error occurred\n");
1992                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1993                 ret = NF_ACCEPT;
1994                 goto out;
1995         }
1996
1997         if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1998                 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1999                                                protonum, state);
2000                 if (ret <= 0) {
2001                         ret = -ret;
2002                         goto out;
2003                 }
2004                 /* ICMP[v6] protocol trackers may assign one conntrack. */
2005                 if (skb->_nfct)
2006                         goto out;
2007         }
2008 repeat:
2009         ret = resolve_normal_ct(tmpl, skb, dataoff,
2010                                 protonum, state);
2011         if (ret < 0) {
2012                 /* Too stressed to deal. */
2013                 NF_CT_STAT_INC_ATOMIC(state->net, drop);
2014                 ret = NF_DROP;
2015                 goto out;
2016         }
2017
2018         ct = nf_ct_get(skb, &ctinfo);
2019         if (!ct) {
2020                 /* Not valid part of a connection */
2021                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
2022                 ret = NF_ACCEPT;
2023                 goto out;
2024         }
2025
2026         ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
2027         if (ret <= 0) {
2028                 /* Invalid: inverse of the return code tells
2029                  * the netfilter core what to do */
2030                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
2031                 nf_ct_put(ct);
2032                 skb->_nfct = 0;
2033                 /* Special case: TCP tracker reports an attempt to reopen a
2034                  * closed/aborted connection. We have to go back and create a
2035                  * fresh conntrack.
2036                  */
2037                 if (ret == -NF_REPEAT)
2038                         goto repeat;
2039
2040                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
2041                 if (ret == -NF_DROP)
2042                         NF_CT_STAT_INC_ATOMIC(state->net, drop);
2043
2044                 ret = -ret;
2045                 goto out;
2046         }
2047
2048         if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
2049             !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
2050                 nf_conntrack_event_cache(IPCT_REPLY, ct);
2051 out:
2052         if (tmpl)
2053                 nf_ct_put(tmpl);
2054
2055         return ret;
2056 }
2057 EXPORT_SYMBOL_GPL(nf_conntrack_in);
2058
2059 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
2060    implicitly racy: see __nf_conntrack_confirm */
2061 void nf_conntrack_alter_reply(struct nf_conn *ct,
2062                               const struct nf_conntrack_tuple *newreply)
2063 {
2064         struct nf_conn_help *help = nfct_help(ct);
2065
2066         /* Should be unconfirmed, so not in hash table yet */
2067         WARN_ON(nf_ct_is_confirmed(ct));
2068
2069         pr_debug("Altering reply tuple of %p to ", ct);
2070         nf_ct_dump_tuple(newreply);
2071
2072         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
2073         if (ct->master || (help && !hlist_empty(&help->expectations)))
2074                 return;
2075 }
2076 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
2077
2078 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
2079 void __nf_ct_refresh_acct(struct nf_conn *ct,
2080                           enum ip_conntrack_info ctinfo,
2081                           const struct sk_buff *skb,
2082                           u32 extra_jiffies,
2083                           bool do_acct)
2084 {
2085         /* Only update if this is not a fixed timeout */
2086         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
2087                 goto acct;
2088
2089         /* If not in hash table, timer will not be active yet */
2090         if (nf_ct_is_confirmed(ct))
2091                 extra_jiffies += nfct_time_stamp;
2092
2093         if (READ_ONCE(ct->timeout) != extra_jiffies)
2094                 WRITE_ONCE(ct->timeout, extra_jiffies);
2095 acct:
2096         if (do_acct)
2097                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
2098 }
2099 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
2100
2101 bool nf_ct_kill_acct(struct nf_conn *ct,
2102                      enum ip_conntrack_info ctinfo,
2103                      const struct sk_buff *skb)
2104 {
2105         nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
2106
2107         return nf_ct_delete(ct, 0, 0);
2108 }
2109 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
2110
2111 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
2112
2113 #include <linux/netfilter/nfnetlink.h>
2114 #include <linux/netfilter/nfnetlink_conntrack.h>
2115 #include <linux/mutex.h>
2116
2117 /* Generic function for tcp/udp/sctp/dccp and alike. */
2118 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
2119                                const struct nf_conntrack_tuple *tuple)
2120 {
2121         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
2122             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
2123                 goto nla_put_failure;
2124         return 0;
2125
2126 nla_put_failure:
2127         return -1;
2128 }
2129 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
2130
2131 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
2132         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
2133         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
2134 };
2135 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
2136
2137 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
2138                                struct nf_conntrack_tuple *t,
2139                                u_int32_t flags)
2140 {
2141         if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
2142                 if (!tb[CTA_PROTO_SRC_PORT])
2143                         return -EINVAL;
2144
2145                 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
2146         }
2147
2148         if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
2149                 if (!tb[CTA_PROTO_DST_PORT])
2150                         return -EINVAL;
2151
2152                 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
2153         }
2154
2155         return 0;
2156 }
2157 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
2158
2159 unsigned int nf_ct_port_nlattr_tuple_size(void)
2160 {
2161         static unsigned int size __read_mostly;
2162
2163         if (!size)
2164                 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
2165
2166         return size;
2167 }
2168 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
2169 #endif
2170
2171 /* Used by ipt_REJECT and ip6t_REJECT. */
2172 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
2173 {
2174         struct nf_conn *ct;
2175         enum ip_conntrack_info ctinfo;
2176
2177         /* This ICMP is in reverse direction to the packet which caused it */
2178         ct = nf_ct_get(skb, &ctinfo);
2179         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2180                 ctinfo = IP_CT_RELATED_REPLY;
2181         else
2182                 ctinfo = IP_CT_RELATED;
2183
2184         /* Attach to new skbuff, and increment count */
2185         nf_ct_set(nskb, ct, ctinfo);
2186         nf_conntrack_get(skb_nfct(nskb));
2187 }
2188
2189 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2190                                  struct nf_conn *ct,
2191                                  enum ip_conntrack_info ctinfo)
2192 {
2193         const struct nf_nat_hook *nat_hook;
2194         struct nf_conntrack_tuple_hash *h;
2195         struct nf_conntrack_tuple tuple;
2196         unsigned int status;
2197         int dataoff;
2198         u16 l3num;
2199         u8 l4num;
2200
2201         l3num = nf_ct_l3num(ct);
2202
2203         dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2204         if (dataoff <= 0)
2205                 return -1;
2206
2207         if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2208                              l4num, net, &tuple))
2209                 return -1;
2210
2211         if (ct->status & IPS_SRC_NAT) {
2212                 memcpy(tuple.src.u3.all,
2213                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2214                        sizeof(tuple.src.u3.all));
2215                 tuple.src.u.all =
2216                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2217         }
2218
2219         if (ct->status & IPS_DST_NAT) {
2220                 memcpy(tuple.dst.u3.all,
2221                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2222                        sizeof(tuple.dst.u3.all));
2223                 tuple.dst.u.all =
2224                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2225         }
2226
2227         h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2228         if (!h)
2229                 return 0;
2230
2231         /* Store status bits of the conntrack that is clashing to re-do NAT
2232          * mangling according to what it has been done already to this packet.
2233          */
2234         status = ct->status;
2235
2236         nf_ct_put(ct);
2237         ct = nf_ct_tuplehash_to_ctrack(h);
2238         nf_ct_set(skb, ct, ctinfo);
2239
2240         nat_hook = rcu_dereference(nf_nat_hook);
2241         if (!nat_hook)
2242                 return 0;
2243
2244         if (status & IPS_SRC_NAT &&
2245             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2246                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2247                 return -1;
2248
2249         if (status & IPS_DST_NAT &&
2250             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2251                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2252                 return -1;
2253
2254         return 0;
2255 }
2256
2257 /* This packet is coming from userspace via nf_queue, complete the packet
2258  * processing after the helper invocation in nf_confirm().
2259  */
2260 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2261                                enum ip_conntrack_info ctinfo)
2262 {
2263         const struct nf_conntrack_helper *helper;
2264         const struct nf_conn_help *help;
2265         int protoff;
2266
2267         help = nfct_help(ct);
2268         if (!help)
2269                 return 0;
2270
2271         helper = rcu_dereference(help->helper);
2272         if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2273                 return 0;
2274
2275         switch (nf_ct_l3num(ct)) {
2276         case NFPROTO_IPV4:
2277                 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2278                 break;
2279 #if IS_ENABLED(CONFIG_IPV6)
2280         case NFPROTO_IPV6: {
2281                 __be16 frag_off;
2282                 u8 pnum;
2283
2284                 pnum = ipv6_hdr(skb)->nexthdr;
2285                 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2286                                            &frag_off);
2287                 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2288                         return 0;
2289                 break;
2290         }
2291 #endif
2292         default:
2293                 return 0;
2294         }
2295
2296         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2297             !nf_is_loopback_packet(skb)) {
2298                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2299                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2300                         return -1;
2301                 }
2302         }
2303
2304         /* We've seen it coming out the other side: confirm it */
2305         return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2306 }
2307
2308 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2309 {
2310         enum ip_conntrack_info ctinfo;
2311         struct nf_conn *ct;
2312         int err;
2313
2314         ct = nf_ct_get(skb, &ctinfo);
2315         if (!ct)
2316                 return 0;
2317
2318         if (!nf_ct_is_confirmed(ct)) {
2319                 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2320                 if (err < 0)
2321                         return err;
2322
2323                 ct = nf_ct_get(skb, &ctinfo);
2324         }
2325
2326         return nf_confirm_cthelper(skb, ct, ctinfo);
2327 }
2328
2329 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2330                                        const struct sk_buff *skb)
2331 {
2332         const struct nf_conntrack_tuple *src_tuple;
2333         const struct nf_conntrack_tuple_hash *hash;
2334         struct nf_conntrack_tuple srctuple;
2335         enum ip_conntrack_info ctinfo;
2336         struct nf_conn *ct;
2337
2338         ct = nf_ct_get(skb, &ctinfo);
2339         if (ct) {
2340                 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2341                 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2342                 return true;
2343         }
2344
2345         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2346                                NFPROTO_IPV4, dev_net(skb->dev),
2347                                &srctuple))
2348                 return false;
2349
2350         hash = nf_conntrack_find_get(dev_net(skb->dev),
2351                                      &nf_ct_zone_dflt,
2352                                      &srctuple);
2353         if (!hash)
2354                 return false;
2355
2356         ct = nf_ct_tuplehash_to_ctrack(hash);
2357         src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2358         memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2359         nf_ct_put(ct);
2360
2361         return true;
2362 }
2363
2364 /* Bring out ya dead! */
2365 static struct nf_conn *
2366 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2367                 const struct nf_ct_iter_data *iter_data, unsigned int *bucket)
2368 {
2369         struct nf_conntrack_tuple_hash *h;
2370         struct nf_conn *ct;
2371         struct hlist_nulls_node *n;
2372         spinlock_t *lockp;
2373
2374         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2375                 struct hlist_nulls_head *hslot = &nf_conntrack_hash[*bucket];
2376
2377                 if (hlist_nulls_empty(hslot))
2378                         continue;
2379
2380                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2381                 local_bh_disable();
2382                 nf_conntrack_lock(lockp);
2383                 hlist_nulls_for_each_entry(h, n, hslot, hnnode) {
2384                         if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2385                                 continue;
2386                         /* All nf_conn objects are added to hash table twice, one
2387                          * for original direction tuple, once for the reply tuple.
2388                          *
2389                          * Exception: In the IPS_NAT_CLASH case, only the reply
2390                          * tuple is added (the original tuple already existed for
2391                          * a different object).
2392                          *
2393                          * We only need to call the iterator once for each
2394                          * conntrack, so we just use the 'reply' direction
2395                          * tuple while iterating.
2396                          */
2397                         ct = nf_ct_tuplehash_to_ctrack(h);
2398
2399                         if (iter_data->net &&
2400                             !net_eq(iter_data->net, nf_ct_net(ct)))
2401                                 continue;
2402
2403                         if (iter(ct, iter_data->data))
2404                                 goto found;
2405                 }
2406                 spin_unlock(lockp);
2407                 local_bh_enable();
2408                 cond_resched();
2409         }
2410
2411         return NULL;
2412 found:
2413         refcount_inc(&ct->ct_general.use);
2414         spin_unlock(lockp);
2415         local_bh_enable();
2416         return ct;
2417 }
2418
2419 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2420                                   const struct nf_ct_iter_data *iter_data)
2421 {
2422         unsigned int bucket = 0;
2423         struct nf_conn *ct;
2424
2425         might_sleep();
2426
2427         mutex_lock(&nf_conntrack_mutex);
2428         while ((ct = get_next_corpse(iter, iter_data, &bucket)) != NULL) {
2429                 /* Time to push up daises... */
2430
2431                 nf_ct_delete(ct, iter_data->portid, iter_data->report);
2432                 nf_ct_put(ct);
2433                 cond_resched();
2434         }
2435         mutex_unlock(&nf_conntrack_mutex);
2436 }
2437
2438 void nf_ct_iterate_cleanup_net(int (*iter)(struct nf_conn *i, void *data),
2439                                const struct nf_ct_iter_data *iter_data)
2440 {
2441         struct net *net = iter_data->net;
2442         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2443
2444         might_sleep();
2445
2446         if (atomic_read(&cnet->count) == 0)
2447                 return;
2448
2449         nf_ct_iterate_cleanup(iter, iter_data);
2450 }
2451 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2452
2453 /**
2454  * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2455  * @iter: callback to invoke for each conntrack
2456  * @data: data to pass to @iter
2457  *
2458  * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2459  * unconfirmed list as dying (so they will not be inserted into
2460  * main table).
2461  *
2462  * Can only be called in module exit path.
2463  */
2464 void
2465 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2466 {
2467         struct nf_ct_iter_data iter_data = {};
2468         struct net *net;
2469
2470         down_read(&net_rwsem);
2471         for_each_net(net) {
2472                 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2473
2474                 if (atomic_read(&cnet->count) == 0)
2475                         continue;
2476                 nf_queue_nf_hook_drop(net);
2477         }
2478         up_read(&net_rwsem);
2479
2480         /* Need to wait for netns cleanup worker to finish, if its
2481          * running -- it might have deleted a net namespace from
2482          * the global list, so hook drop above might not have
2483          * affected all namespaces.
2484          */
2485         net_ns_barrier();
2486
2487         /* a skb w. unconfirmed conntrack could have been reinjected just
2488          * before we called nf_queue_nf_hook_drop().
2489          *
2490          * This makes sure its inserted into conntrack table.
2491          */
2492         synchronize_net();
2493
2494         nf_ct_ext_bump_genid();
2495         iter_data.data = data;
2496         nf_ct_iterate_cleanup(iter, &iter_data);
2497
2498         /* Another cpu might be in a rcu read section with
2499          * rcu protected pointer cleared in iter callback
2500          * or hidden via nf_ct_ext_bump_genid() above.
2501          *
2502          * Wait until those are done.
2503          */
2504         synchronize_rcu();
2505 }
2506 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2507
2508 static int kill_all(struct nf_conn *i, void *data)
2509 {
2510         return 1;
2511 }
2512
2513 void nf_conntrack_cleanup_start(void)
2514 {
2515         cleanup_nf_conntrack_bpf();
2516         conntrack_gc_work.exiting = true;
2517 }
2518
2519 void nf_conntrack_cleanup_end(void)
2520 {
2521         RCU_INIT_POINTER(nf_ct_hook, NULL);
2522         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2523         kvfree(nf_conntrack_hash);
2524
2525         nf_conntrack_proto_fini();
2526         nf_conntrack_helper_fini();
2527         nf_conntrack_expect_fini();
2528
2529         kmem_cache_destroy(nf_conntrack_cachep);
2530 }
2531
2532 /*
2533  * Mishearing the voices in his head, our hero wonders how he's
2534  * supposed to kill the mall.
2535  */
2536 void nf_conntrack_cleanup_net(struct net *net)
2537 {
2538         LIST_HEAD(single);
2539
2540         list_add(&net->exit_list, &single);
2541         nf_conntrack_cleanup_net_list(&single);
2542 }
2543
2544 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2545 {
2546         struct nf_ct_iter_data iter_data = {};
2547         struct net *net;
2548         int busy;
2549
2550         /*
2551          * This makes sure all current packets have passed through
2552          *  netfilter framework.  Roll on, two-stage module
2553          *  delete...
2554          */
2555         synchronize_net();
2556 i_see_dead_people:
2557         busy = 0;
2558         list_for_each_entry(net, net_exit_list, exit_list) {
2559                 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2560
2561                 iter_data.net = net;
2562                 nf_ct_iterate_cleanup_net(kill_all, &iter_data);
2563                 if (atomic_read(&cnet->count) != 0)
2564                         busy = 1;
2565         }
2566         if (busy) {
2567                 schedule();
2568                 goto i_see_dead_people;
2569         }
2570
2571         list_for_each_entry(net, net_exit_list, exit_list) {
2572                 nf_conntrack_ecache_pernet_fini(net);
2573                 nf_conntrack_expect_pernet_fini(net);
2574                 free_percpu(net->ct.stat);
2575         }
2576 }
2577
2578 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2579 {
2580         struct hlist_nulls_head *hash;
2581         unsigned int nr_slots, i;
2582
2583         if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2584                 return NULL;
2585
2586         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2587         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2588
2589         hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2590
2591         if (hash && nulls)
2592                 for (i = 0; i < nr_slots; i++)
2593                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
2594
2595         return hash;
2596 }
2597 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2598
2599 int nf_conntrack_hash_resize(unsigned int hashsize)
2600 {
2601         int i, bucket;
2602         unsigned int old_size;
2603         struct hlist_nulls_head *hash, *old_hash;
2604         struct nf_conntrack_tuple_hash *h;
2605         struct nf_conn *ct;
2606
2607         if (!hashsize)
2608                 return -EINVAL;
2609
2610         hash = nf_ct_alloc_hashtable(&hashsize, 1);
2611         if (!hash)
2612                 return -ENOMEM;
2613
2614         mutex_lock(&nf_conntrack_mutex);
2615         old_size = nf_conntrack_htable_size;
2616         if (old_size == hashsize) {
2617                 mutex_unlock(&nf_conntrack_mutex);
2618                 kvfree(hash);
2619                 return 0;
2620         }
2621
2622         local_bh_disable();
2623         nf_conntrack_all_lock();
2624         write_seqcount_begin(&nf_conntrack_generation);
2625
2626         /* Lookups in the old hash might happen in parallel, which means we
2627          * might get false negatives during connection lookup. New connections
2628          * created because of a false negative won't make it into the hash
2629          * though since that required taking the locks.
2630          */
2631
2632         for (i = 0; i < nf_conntrack_htable_size; i++) {
2633                 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2634                         unsigned int zone_id;
2635
2636                         h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2637                                               struct nf_conntrack_tuple_hash, hnnode);
2638                         ct = nf_ct_tuplehash_to_ctrack(h);
2639                         hlist_nulls_del_rcu(&h->hnnode);
2640
2641                         zone_id = nf_ct_zone_id(nf_ct_zone(ct), NF_CT_DIRECTION(h));
2642                         bucket = __hash_conntrack(nf_ct_net(ct),
2643                                                   &h->tuple, zone_id, hashsize);
2644                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2645                 }
2646         }
2647         old_hash = nf_conntrack_hash;
2648
2649         nf_conntrack_hash = hash;
2650         nf_conntrack_htable_size = hashsize;
2651
2652         write_seqcount_end(&nf_conntrack_generation);
2653         nf_conntrack_all_unlock();
2654         local_bh_enable();
2655
2656         mutex_unlock(&nf_conntrack_mutex);
2657
2658         synchronize_net();
2659         kvfree(old_hash);
2660         return 0;
2661 }
2662
2663 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2664 {
2665         unsigned int hashsize;
2666         int rc;
2667
2668         if (current->nsproxy->net_ns != &init_net)
2669                 return -EOPNOTSUPP;
2670
2671         /* On boot, we can set this without any fancy locking. */
2672         if (!nf_conntrack_hash)
2673                 return param_set_uint(val, kp);
2674
2675         rc = kstrtouint(val, 0, &hashsize);
2676         if (rc)
2677                 return rc;
2678
2679         return nf_conntrack_hash_resize(hashsize);
2680 }
2681
2682 int nf_conntrack_init_start(void)
2683 {
2684         unsigned long nr_pages = totalram_pages();
2685         int max_factor = 8;
2686         int ret = -ENOMEM;
2687         int i;
2688
2689         seqcount_spinlock_init(&nf_conntrack_generation,
2690                                &nf_conntrack_locks_all_lock);
2691
2692         for (i = 0; i < CONNTRACK_LOCKS; i++)
2693                 spin_lock_init(&nf_conntrack_locks[i]);
2694
2695         if (!nf_conntrack_htable_size) {
2696                 nf_conntrack_htable_size
2697                         = (((nr_pages << PAGE_SHIFT) / 16384)
2698                            / sizeof(struct hlist_head));
2699                 if (BITS_PER_LONG >= 64 &&
2700                     nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2701                         nf_conntrack_htable_size = 262144;
2702                 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2703                         nf_conntrack_htable_size = 65536;
2704
2705                 if (nf_conntrack_htable_size < 1024)
2706                         nf_conntrack_htable_size = 1024;
2707                 /* Use a max. factor of one by default to keep the average
2708                  * hash chain length at 2 entries.  Each entry has to be added
2709                  * twice (once for original direction, once for reply).
2710                  * When a table size is given we use the old value of 8 to
2711                  * avoid implicit reduction of the max entries setting.
2712                  */
2713                 max_factor = 1;
2714         }
2715
2716         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2717         if (!nf_conntrack_hash)
2718                 return -ENOMEM;
2719
2720         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2721
2722         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2723                                                 sizeof(struct nf_conn),
2724                                                 NFCT_INFOMASK + 1,
2725                                                 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2726         if (!nf_conntrack_cachep)
2727                 goto err_cachep;
2728
2729         ret = nf_conntrack_expect_init();
2730         if (ret < 0)
2731                 goto err_expect;
2732
2733         ret = nf_conntrack_helper_init();
2734         if (ret < 0)
2735                 goto err_helper;
2736
2737         ret = nf_conntrack_proto_init();
2738         if (ret < 0)
2739                 goto err_proto;
2740
2741         conntrack_gc_work_init(&conntrack_gc_work);
2742         queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2743
2744         ret = register_nf_conntrack_bpf();
2745         if (ret < 0)
2746                 goto err_kfunc;
2747
2748         return 0;
2749
2750 err_kfunc:
2751         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2752         nf_conntrack_proto_fini();
2753 err_proto:
2754         nf_conntrack_helper_fini();
2755 err_helper:
2756         nf_conntrack_expect_fini();
2757 err_expect:
2758         kmem_cache_destroy(nf_conntrack_cachep);
2759 err_cachep:
2760         kvfree(nf_conntrack_hash);
2761         return ret;
2762 }
2763
2764 static const struct nf_ct_hook nf_conntrack_hook = {
2765         .update         = nf_conntrack_update,
2766         .destroy        = nf_ct_destroy,
2767         .get_tuple_skb  = nf_conntrack_get_tuple_skb,
2768         .attach         = nf_conntrack_attach,
2769 };
2770
2771 void nf_conntrack_init_end(void)
2772 {
2773         RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2774 }
2775
2776 /*
2777  * We need to use special "null" values, not used in hash table
2778  */
2779 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
2780
2781 int nf_conntrack_init_net(struct net *net)
2782 {
2783         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2784         int ret = -ENOMEM;
2785
2786         BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2787         BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2788         atomic_set(&cnet->count, 0);
2789
2790         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2791         if (!net->ct.stat)
2792                 return ret;
2793
2794         ret = nf_conntrack_expect_pernet_init(net);
2795         if (ret < 0)
2796                 goto err_expect;
2797
2798         nf_conntrack_acct_pernet_init(net);
2799         nf_conntrack_tstamp_pernet_init(net);
2800         nf_conntrack_ecache_pernet_init(net);
2801         nf_conntrack_proto_pernet_init(net);
2802
2803         return 0;
2804
2805 err_expect:
2806         free_percpu(net->ct.stat);
2807         return ret;
2808 }
2809
2810 /* ctnetlink code shared by both ctnetlink and nf_conntrack_bpf */
2811
2812 int __nf_ct_change_timeout(struct nf_conn *ct, u64 timeout)
2813 {
2814         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
2815                 return -EPERM;
2816
2817         __nf_ct_set_timeout(ct, timeout);
2818
2819         if (test_bit(IPS_DYING_BIT, &ct->status))
2820                 return -ETIME;
2821
2822         return 0;
2823 }
2824 EXPORT_SYMBOL_GPL(__nf_ct_change_timeout);
2825
2826 void __nf_ct_change_status(struct nf_conn *ct, unsigned long on, unsigned long off)
2827 {
2828         unsigned int bit;
2829
2830         /* Ignore these unchangable bits */
2831         on &= ~IPS_UNCHANGEABLE_MASK;
2832         off &= ~IPS_UNCHANGEABLE_MASK;
2833
2834         for (bit = 0; bit < __IPS_MAX_BIT; bit++) {
2835                 if (on & (1 << bit))
2836                         set_bit(bit, &ct->status);
2837                 else if (off & (1 << bit))
2838                         clear_bit(bit, &ct->status);
2839         }
2840 }
2841 EXPORT_SYMBOL_GPL(__nf_ct_change_status);
2842
2843 int nf_ct_change_status_common(struct nf_conn *ct, unsigned int status)
2844 {
2845         unsigned long d;
2846
2847         d = ct->status ^ status;
2848
2849         if (d & (IPS_EXPECTED|IPS_CONFIRMED|IPS_DYING))
2850                 /* unchangeable */
2851                 return -EBUSY;
2852
2853         if (d & IPS_SEEN_REPLY && !(status & IPS_SEEN_REPLY))
2854                 /* SEEN_REPLY bit can only be set */
2855                 return -EBUSY;
2856
2857         if (d & IPS_ASSURED && !(status & IPS_ASSURED))
2858                 /* ASSURED bit can only be set */
2859                 return -EBUSY;
2860
2861         __nf_ct_change_status(ct, status, 0);
2862         return 0;
2863 }
2864 EXPORT_SYMBOL_GPL(nf_ct_change_status_common);