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/jhash.h>
  25 #include <linux/siphash.h>
  26 #include <linux/err.h>
  27 #include <linux/percpu.h>
  28 #include <linux/moduleparam.h>
  29 #include <linux/notifier.h>
  30 #include <linux/kernel.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/socket.h>
  33 #include <linux/mm.h>
  34 #include <linux/nsproxy.h>
  35 #include <linux/rculist_nulls.h>
  36
  37 #include <net/netfilter/nf_conntrack.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_seqadj.h>
  42 #include <net/netfilter/nf_conntrack_core.h>
  43 #include <net/netfilter/nf_conntrack_extend.h>
  44 #include <net/netfilter/nf_conntrack_acct.h>
  45 #include <net/netfilter/nf_conntrack_ecache.h>
  46 #include <net/netfilter/nf_conntrack_zones.h>
  47 #include <net/netfilter/nf_conntrack_timestamp.h>
  48 #include <net/netfilter/nf_conntrack_timeout.h>
  49 #include <net/netfilter/nf_conntrack_labels.h>
  50 #include <net/netfilter/nf_conntrack_synproxy.h>
  51 #include <net/netfilter/nf_nat.h>
  52 #include <net/netfilter/nf_nat_helper.h>
  53 #include <net/netns/hash.h>
  54 #include <net/ip.h>
  55
  56 #include "nf_internals.h"
  57
  58 __cacheline_aligned_in_smp spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
  59 EXPORT_SYMBOL_GPL(nf_conntrack_locks);
  60
  61 __cacheline_aligned_in_smp DEFINE_SPINLOCK(nf_conntrack_expect_lock);
  62 EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
  63
  64 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
  65 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
  66
  67 struct conntrack_gc_work {
  68         struct delayed_work     dwork;
  69         u32                     last_bucket;
  70         bool                    exiting;
  71         bool                    early_drop;
  72         long                    next_gc_run;
  73 };
  74
  75 static __read_mostly struct kmem_cache *nf_conntrack_cachep;
  76 static DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
  77 static __read_mostly bool nf_conntrack_locks_all;
  78
  79 /* every gc cycle scans at most 1/GC_MAX_BUCKETS_DIV part of table */
  80 #define GC_MAX_BUCKETS_DIV      128u
  81 /* upper bound of full table scan */
  82 #define GC_MAX_SCAN_JIFFIES     (16u * HZ)
  83 /* desired ratio of entries found to be expired */
  84 #define GC_EVICT_RATIO  50u
  85
  86 static struct conntrack_gc_work conntrack_gc_work;
  87
  88 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
  89 {
  90         /* 1) Acquire the lock */
  91         spin_lock(lock);
  92
  93         /* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
  94          * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
  95          */
  96         if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
  97                 return;
  98
  99         /* fast path failed, unlock */
 100         spin_unlock(lock);
 101
 102         /* Slow path 1) get global lock */
 103         spin_lock(&nf_conntrack_locks_all_lock);
 104
 105         /* Slow path 2) get the lock we want */
 106         spin_lock(lock);
 107
 108         /* Slow path 3) release the global lock */
 109         spin_unlock(&nf_conntrack_locks_all_lock);
 110 }
 111 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
 112
 113 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
 114 {
 115         h1 %= CONNTRACK_LOCKS;
 116         h2 %= CONNTRACK_LOCKS;
 117         spin_unlock(&nf_conntrack_locks[h1]);
 118         if (h1 != h2)
 119                 spin_unlock(&nf_conntrack_locks[h2]);
 120 }
 121
 122 /* return true if we need to recompute hashes (in case hash table was resized) */
 123 static bool nf_conntrack_double_lock(struct net *net, unsigned int h1,
 124                                      unsigned int h2, unsigned int sequence)
 125 {
 126         h1 %= CONNTRACK_LOCKS;
 127         h2 %= CONNTRACK_LOCKS;
 128         if (h1 <= h2) {
 129                 nf_conntrack_lock(&nf_conntrack_locks[h1]);
 130                 if (h1 != h2)
 131                         spin_lock_nested(&nf_conntrack_locks[h2],
 132                                          SINGLE_DEPTH_NESTING);
 133         } else {
 134                 nf_conntrack_lock(&nf_conntrack_locks[h2]);
 135                 spin_lock_nested(&nf_conntrack_locks[h1],
 136                                  SINGLE_DEPTH_NESTING);
 137         }
 138         if (read_seqcount_retry(&nf_conntrack_generation, sequence)) {
 139                 nf_conntrack_double_unlock(h1, h2);
 140                 return true;
 141         }
 142         return false;
 143 }
 144
 145 static void nf_conntrack_all_lock(void)
 146         __acquires(&nf_conntrack_locks_all_lock)
 147 {
 148         int i;
 149
 150         spin_lock(&nf_conntrack_locks_all_lock);
 151
 152         nf_conntrack_locks_all = true;
 153
 154         for (i = 0; i < CONNTRACK_LOCKS; i++) {
 155                 spin_lock(&nf_conntrack_locks[i]);
 156
 157                 /* This spin_unlock provides the "release" to ensure that
 158                  * nf_conntrack_locks_all==true is visible to everyone that
 159                  * acquired spin_lock(&nf_conntrack_locks[]).
 160                  */
 161                 spin_unlock(&nf_conntrack_locks[i]);
 162         }
 163 }
 164
 165 static void nf_conntrack_all_unlock(void)
 166         __releases(&nf_conntrack_locks_all_lock)
 167 {
 168         /* All prior stores must be complete before we clear
 169          * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
 170          * might observe the false value but not the entire
 171          * critical section.
 172          * It pairs with the smp_load_acquire() in nf_conntrack_lock()
 173          */
 174         smp_store_release(&nf_conntrack_locks_all, false);
 175         spin_unlock(&nf_conntrack_locks_all_lock);
 176 }
 177
 178 unsigned int nf_conntrack_htable_size __read_mostly;
 179 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
 180
 181 unsigned int nf_conntrack_max __read_mostly;
 182 EXPORT_SYMBOL_GPL(nf_conntrack_max);
 183 seqcount_spinlock_t nf_conntrack_generation __read_mostly;
 184 static unsigned int nf_conntrack_hash_rnd __read_mostly;
 185
 186 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
 187                               const struct net *net)
 188 {
 189         unsigned int n;
 190         u32 seed;
 191
 192         get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
 193
 194         /* The direction must be ignored, so we hash everything up to the
 195          * destination ports (which is a multiple of 4) and treat the last
 196          * three bytes manually.
 197          */
 198         seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
 199         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
 200         return jhash2((u32 *)tuple, n, seed ^
 201                       (((__force __u16)tuple->dst.u.all << 16) |
 202                       tuple->dst.protonum));
 203 }
 204
 205 static u32 scale_hash(u32 hash)
 206 {
 207         return reciprocal_scale(hash, nf_conntrack_htable_size);
 208 }
 209
 210 static u32 __hash_conntrack(const struct net *net,
 211                             const struct nf_conntrack_tuple *tuple,
 212                             unsigned int size)
 213 {
 214         return reciprocal_scale(hash_conntrack_raw(tuple, net), size);
 215 }
 216
 217 static u32 hash_conntrack(const struct net *net,
 218                           const struct nf_conntrack_tuple *tuple)
 219 {
 220         return scale_hash(hash_conntrack_raw(tuple, net));
 221 }
 222
 223 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
 224                                   unsigned int dataoff,
 225                                   struct nf_conntrack_tuple *tuple)
 226 {       struct {
 227                 __be16 sport;
 228                 __be16 dport;
 229         } _inet_hdr, *inet_hdr;
 230
 231         /* Actually only need first 4 bytes to get ports. */
 232         inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
 233         if (!inet_hdr)
 234                 return false;
 235
 236         tuple->src.u.udp.port = inet_hdr->sport;
 237         tuple->dst.u.udp.port = inet_hdr->dport;
 238         return true;
 239 }
 240
 241 static bool
 242 nf_ct_get_tuple(const struct sk_buff *skb,
 243                 unsigned int nhoff,
 244                 unsigned int dataoff,
 245                 u_int16_t l3num,
 246                 u_int8_t protonum,
 247                 struct net *net,
 248                 struct nf_conntrack_tuple *tuple)
 249 {
 250         unsigned int size;
 251         const __be32 *ap;
 252         __be32 _addrs[8];
 253
 254         memset(tuple, 0, sizeof(*tuple));
 255
 256         tuple->src.l3num = l3num;
 257         switch (l3num) {
 258         case NFPROTO_IPV4:
 259                 nhoff += offsetof(struct iphdr, saddr);
 260                 size = 2 * sizeof(__be32);
 261                 break;
 262         case NFPROTO_IPV6:
 263                 nhoff += offsetof(struct ipv6hdr, saddr);
 264                 size = sizeof(_addrs);
 265                 break;
 266         default:
 267                 return true;
 268         }
 269
 270         ap = skb_header_pointer(skb, nhoff, size, _addrs);
 271         if (!ap)
 272                 return false;
 273
 274         switch (l3num) {
 275         case NFPROTO_IPV4:
 276                 tuple->src.u3.ip = ap[0];
 277                 tuple->dst.u3.ip = ap[1];
 278                 break;
 279         case NFPROTO_IPV6:
 280                 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
 281                 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
 282                 break;
 283         }
 284
 285         tuple->dst.protonum = protonum;
 286         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 287
 288         switch (protonum) {
 289 #if IS_ENABLED(CONFIG_IPV6)
 290         case IPPROTO_ICMPV6:
 291                 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
 292 #endif
 293         case IPPROTO_ICMP:
 294                 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
 295 #ifdef CONFIG_NF_CT_PROTO_GRE
 296         case IPPROTO_GRE:
 297                 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
 298 #endif
 299         case IPPROTO_TCP:
 300         case IPPROTO_UDP: /* fallthrough */
 301                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 302 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
 303         case IPPROTO_UDPLITE:
 304                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 305 #endif
 306 #ifdef CONFIG_NF_CT_PROTO_SCTP
 307         case IPPROTO_SCTP:
 308                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 309 #endif
 310 #ifdef CONFIG_NF_CT_PROTO_DCCP
 311         case IPPROTO_DCCP:
 312                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 313 #endif
 314         default:
 315                 break;
 316         }
 317
 318         return true;
 319 }
 320
 321 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 322                             u_int8_t *protonum)
 323 {
 324         int dataoff = -1;
 325         const struct iphdr *iph;
 326         struct iphdr _iph;
 327
 328         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
 329         if (!iph)
 330                 return -1;
 331
 332         /* Conntrack defragments packets, we might still see fragments
 333          * inside ICMP packets though.
 334          */
 335         if (iph->frag_off & htons(IP_OFFSET))
 336                 return -1;
 337
 338         dataoff = nhoff + (iph->ihl << 2);
 339         *protonum = iph->protocol;
 340
 341         /* Check bogus IP headers */
 342         if (dataoff > skb->len) {
 343                 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
 344                          nhoff, iph->ihl << 2, skb->len);
 345                 return -1;
 346         }
 347         return dataoff;
 348 }
 349
 350 #if IS_ENABLED(CONFIG_IPV6)
 351 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 352                             u8 *protonum)
 353 {
 354         int protoff = -1;
 355         unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
 356         __be16 frag_off;
 357         u8 nexthdr;
 358
 359         if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
 360                           &nexthdr, sizeof(nexthdr)) != 0) {
 361                 pr_debug("can't get nexthdr\n");
 362                 return -1;
 363         }
 364         protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
 365         /*
 366          * (protoff == skb->len) means the packet has not data, just
 367          * IPv6 and possibly extensions headers, but it is tracked anyway
 368          */
 369         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 370                 pr_debug("can't find proto in pkt\n");
 371                 return -1;
 372         }
 373
 374         *protonum = nexthdr;
 375         return protoff;
 376 }
 377 #endif
 378
 379 static int get_l4proto(const struct sk_buff *skb,
 380                        unsigned int nhoff, u8 pf, u8 *l4num)
 381 {
 382         switch (pf) {
 383         case NFPROTO_IPV4:
 384                 return ipv4_get_l4proto(skb, nhoff, l4num);
 385 #if IS_ENABLED(CONFIG_IPV6)
 386         case NFPROTO_IPV6:
 387                 return ipv6_get_l4proto(skb, nhoff, l4num);
 388 #endif
 389         default:
 390                 *l4num = 0;
 391                 break;
 392         }
 393         return -1;
 394 }
 395
 396 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 397                        u_int16_t l3num,
 398                        struct net *net, struct nf_conntrack_tuple *tuple)
 399 {
 400         u8 protonum;
 401         int protoff;
 402
 403         protoff = get_l4proto(skb, nhoff, l3num, &protonum);
 404         if (protoff <= 0)
 405                 return false;
 406
 407         return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
 408 }
 409 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 410
 411 bool
 412 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 413                    const struct nf_conntrack_tuple *orig)
 414 {
 415         memset(inverse, 0, sizeof(*inverse));
 416
 417         inverse->src.l3num = orig->src.l3num;
 418
 419         switch (orig->src.l3num) {
 420         case NFPROTO_IPV4:
 421                 inverse->src.u3.ip = orig->dst.u3.ip;
 422                 inverse->dst.u3.ip = orig->src.u3.ip;
 423                 break;
 424         case NFPROTO_IPV6:
 425                 inverse->src.u3.in6 = orig->dst.u3.in6;
 426                 inverse->dst.u3.in6 = orig->src.u3.in6;
 427                 break;
 428         default:
 429                 break;
 430         }
 431
 432         inverse->dst.dir = !orig->dst.dir;
 433
 434         inverse->dst.protonum = orig->dst.protonum;
 435
 436         switch (orig->dst.protonum) {
 437         case IPPROTO_ICMP:
 438                 return nf_conntrack_invert_icmp_tuple(inverse, orig);
 439 #if IS_ENABLED(CONFIG_IPV6)
 440         case IPPROTO_ICMPV6:
 441                 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
 442 #endif
 443         }
 444
 445         inverse->src.u.all = orig->dst.u.all;
 446         inverse->dst.u.all = orig->src.u.all;
 447         return true;
 448 }
 449 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 450
 451 /* Generate a almost-unique pseudo-id for a given conntrack.
 452  *
 453  * intentionally doesn't re-use any of the seeds used for hash
 454  * table location, we assume id gets exposed to userspace.
 455  *
 456  * Following nf_conn items do not change throughout lifetime
 457  * of the nf_conn:
 458  *
 459  * 1. nf_conn address
 460  * 2. nf_conn->master address (normally NULL)
 461  * 3. the associated net namespace
 462  * 4. the original direction tuple
 463  */
 464 u32 nf_ct_get_id(const struct nf_conn *ct)
 465 {
 466         static __read_mostly siphash_key_t ct_id_seed;
 467         unsigned long a, b, c, d;
 468
 469         net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
 470
 471         a = (unsigned long)ct;
 472         b = (unsigned long)ct->master;
 473         c = (unsigned long)nf_ct_net(ct);
 474         d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 475                                    sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
 476                                    &ct_id_seed);
 477 #ifdef CONFIG_64BIT
 478         return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
 479 #else
 480         return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
 481 #endif
 482 }
 483 EXPORT_SYMBOL_GPL(nf_ct_get_id);
 484
 485 static void
 486 clean_from_lists(struct nf_conn *ct)
 487 {
 488         pr_debug("clean_from_lists(%p)\n", ct);
 489         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 490         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 491
 492         /* Destroy all pending expectations */
 493         nf_ct_remove_expectations(ct);
 494 }
 495
 496 /* must be called with local_bh_disable */
 497 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
 498 {
 499         struct ct_pcpu *pcpu;
 500
 501         /* add this conntrack to the (per cpu) dying list */
 502         ct->cpu = smp_processor_id();
 503         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 504
 505         spin_lock(&pcpu->lock);
 506         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 507                              &pcpu->dying);
 508         spin_unlock(&pcpu->lock);
 509 }
 510
 511 /* must be called with local_bh_disable */
 512 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
 513 {
 514         struct ct_pcpu *pcpu;
 515
 516         /* add this conntrack to the (per cpu) unconfirmed list */
 517         ct->cpu = smp_processor_id();
 518         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 519
 520         spin_lock(&pcpu->lock);
 521         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 522                              &pcpu->unconfirmed);
 523         spin_unlock(&pcpu->lock);
 524 }
 525
 526 /* must be called with local_bh_disable */
 527 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
 528 {
 529         struct ct_pcpu *pcpu;
 530
 531         /* We overload first tuple to link into unconfirmed or dying list.*/
 532         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 533
 534         spin_lock(&pcpu->lock);
 535         BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 536         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 537         spin_unlock(&pcpu->lock);
 538 }
 539
 540 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
 541
 542 /* Released via destroy_conntrack() */
 543 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 544                                  const struct nf_conntrack_zone *zone,
 545                                  gfp_t flags)
 546 {
 547         struct nf_conn *tmpl, *p;
 548
 549         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
 550                 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
 551                 if (!tmpl)
 552                         return NULL;
 553
 554                 p = tmpl;
 555                 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 556                 if (tmpl != p) {
 557                         tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 558                         tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
 559                 }
 560         } else {
 561                 tmpl = kzalloc(sizeof(*tmpl), flags);
 562                 if (!tmpl)
 563                         return NULL;
 564         }
 565
 566         tmpl->status = IPS_TEMPLATE;
 567         write_pnet(&tmpl->ct_net, net);
 568         nf_ct_zone_add(tmpl, zone);
 569         atomic_set(&tmpl->ct_general.use, 0);
 570
 571         return tmpl;
 572 }
 573 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
 574
 575 void nf_ct_tmpl_free(struct nf_conn *tmpl)
 576 {
 577         nf_ct_ext_destroy(tmpl);
 578
 579         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
 580                 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
 581         else
 582                 kfree(tmpl);
 583 }
 584 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
 585
 586 static void destroy_gre_conntrack(struct nf_conn *ct)
 587 {
 588 #ifdef CONFIG_NF_CT_PROTO_GRE
 589         struct nf_conn *master = ct->master;
 590
 591         if (master)
 592                 nf_ct_gre_keymap_destroy(master);
 593 #endif
 594 }
 595
 596 static void
 597 destroy_conntrack(struct nf_conntrack *nfct)
 598 {
 599         struct nf_conn *ct = (struct nf_conn *)nfct;
 600
 601         pr_debug("destroy_conntrack(%p)\n", ct);
 602         WARN_ON(atomic_read(&nfct->use) != 0);
 603
 604         if (unlikely(nf_ct_is_template(ct))) {
 605                 nf_ct_tmpl_free(ct);
 606                 return;
 607         }
 608
 609         if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
 610                 destroy_gre_conntrack(ct);
 611
 612         local_bh_disable();
 613         /* Expectations will have been removed in clean_from_lists,
 614          * except TFTP can create an expectation on the first packet,
 615          * before connection is in the list, so we need to clean here,
 616          * too.
 617          */
 618         nf_ct_remove_expectations(ct);
 619
 620         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 621
 622         local_bh_enable();
 623
 624         if (ct->master)
 625                 nf_ct_put(ct->master);
 626
 627         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 628         nf_conntrack_free(ct);
 629 }
 630
 631 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 632 {
 633         struct net *net = nf_ct_net(ct);
 634         unsigned int hash, reply_hash;
 635         unsigned int sequence;
 636
 637         nf_ct_helper_destroy(ct);
 638
 639         local_bh_disable();
 640         do {
 641                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 642                 hash = hash_conntrack(net,
 643                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 644                 reply_hash = hash_conntrack(net,
 645                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 646         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 647
 648         clean_from_lists(ct);
 649         nf_conntrack_double_unlock(hash, reply_hash);
 650
 651         nf_ct_add_to_dying_list(ct);
 652
 653         local_bh_enable();
 654 }
 655
 656 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 657 {
 658         struct nf_conn_tstamp *tstamp;
 659         struct net *net;
 660
 661         if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
 662                 return false;
 663
 664         tstamp = nf_conn_tstamp_find(ct);
 665         if (tstamp && tstamp->stop == 0)
 666                 tstamp->stop = ktime_get_real_ns();
 667
 668         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 669                                     portid, report) < 0) {
 670                 /* destroy event was not delivered. nf_ct_put will
 671                  * be done by event cache worker on redelivery.
 672                  */
 673                 nf_ct_delete_from_lists(ct);
 674                 nf_conntrack_ecache_work(nf_ct_net(ct), NFCT_ECACHE_DESTROY_FAIL);
 675                 return false;
 676         }
 677
 678         net = nf_ct_net(ct);
 679         if (nf_conntrack_ecache_dwork_pending(net))
 680                 nf_conntrack_ecache_work(net, NFCT_ECACHE_DESTROY_SENT);
 681         nf_ct_delete_from_lists(ct);
 682         nf_ct_put(ct);
 683         return true;
 684 }
 685 EXPORT_SYMBOL_GPL(nf_ct_delete);
 686
 687 static inline bool
 688 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 689                 const struct nf_conntrack_tuple *tuple,
 690                 const struct nf_conntrack_zone *zone,
 691                 const struct net *net)
 692 {
 693         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 694
 695         /* A conntrack can be recreated with the equal tuple,
 696          * so we need to check that the conntrack is confirmed
 697          */
 698         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 699                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 700                nf_ct_is_confirmed(ct) &&
 701                net_eq(net, nf_ct_net(ct));
 702 }
 703
 704 static inline bool
 705 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
 706 {
 707         return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 708                                  &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
 709                nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
 710                                  &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
 711                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
 712                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
 713                net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
 714 }
 715
 716 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
 717 static void nf_ct_gc_expired(struct nf_conn *ct)
 718 {
 719         if (!atomic_inc_not_zero(&ct->ct_general.use))
 720                 return;
 721
 722         if (nf_ct_should_gc(ct))
 723                 nf_ct_kill(ct);
 724
 725         nf_ct_put(ct);
 726 }
 727
 728 /*
 729  * Warning :
 730  * - Caller must take a reference on returned object
 731  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 732  */
 733 static struct nf_conntrack_tuple_hash *
 734 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 735                       const struct nf_conntrack_tuple *tuple, u32 hash)
 736 {
 737         struct nf_conntrack_tuple_hash *h;
 738         struct hlist_nulls_head *ct_hash;
 739         struct hlist_nulls_node *n;
 740         unsigned int bucket, hsize;
 741
 742 begin:
 743         nf_conntrack_get_ht(&ct_hash, &hsize);
 744         bucket = reciprocal_scale(hash, hsize);
 745
 746         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
 747                 struct nf_conn *ct;
 748
 749                 ct = nf_ct_tuplehash_to_ctrack(h);
 750                 if (nf_ct_is_expired(ct)) {
 751                         nf_ct_gc_expired(ct);
 752                         continue;
 753                 }
 754
 755                 if (nf_ct_key_equal(h, tuple, zone, net))
 756                         return h;
 757         }
 758         /*
 759          * if the nulls value we got at the end of this lookup is
 760          * not the expected one, we must restart lookup.
 761          * We probably met an item that was moved to another chain.
 762          */
 763         if (get_nulls_value(n) != bucket) {
 764                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 765                 goto begin;
 766         }
 767
 768         return NULL;
 769 }
 770
 771 /* Find a connection corresponding to a tuple. */
 772 static struct nf_conntrack_tuple_hash *
 773 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 774                         const struct nf_conntrack_tuple *tuple, u32 hash)
 775 {
 776         struct nf_conntrack_tuple_hash *h;
 777         struct nf_conn *ct;
 778
 779         rcu_read_lock();
 780
 781         h = ____nf_conntrack_find(net, zone, tuple, hash);
 782         if (h) {
 783                 /* We have a candidate that matches the tuple we're interested
 784                  * in, try to obtain a reference and re-check tuple
 785                  */
 786                 ct = nf_ct_tuplehash_to_ctrack(h);
 787                 if (likely(atomic_inc_not_zero(&ct->ct_general.use))) {
 788                         if (likely(nf_ct_key_equal(h, tuple, zone, net)))
 789                                 goto found;
 790
 791                         /* TYPESAFE_BY_RCU recycled the candidate */
 792                         nf_ct_put(ct);
 793                 }
 794
 795                 h = NULL;
 796         }
 797 found:
 798         rcu_read_unlock();
 799
 800         return h;
 801 }
 802
 803 struct nf_conntrack_tuple_hash *
 804 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 805                       const struct nf_conntrack_tuple *tuple)
 806 {
 807         return __nf_conntrack_find_get(net, zone, tuple,
 808                                        hash_conntrack_raw(tuple, net));
 809 }
 810 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 811
 812 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 813                                        unsigned int hash,
 814                                        unsigned int reply_hash)
 815 {
 816         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 817                            &nf_conntrack_hash[hash]);
 818         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 819                            &nf_conntrack_hash[reply_hash]);
 820 }
 821
 822 int
 823 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 824 {
 825         const struct nf_conntrack_zone *zone;
 826         struct net *net = nf_ct_net(ct);
 827         unsigned int hash, reply_hash;
 828         struct nf_conntrack_tuple_hash *h;
 829         struct hlist_nulls_node *n;
 830         unsigned int sequence;
 831
 832         zone = nf_ct_zone(ct);
 833
 834         local_bh_disable();
 835         do {
 836                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 837                 hash = hash_conntrack(net,
 838                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 839                 reply_hash = hash_conntrack(net,
 840                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 841         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 842
 843         /* See if there's one in the list already, including reverse */
 844         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
 845                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 846                                     zone, net))
 847                         goto out;
 848
 849         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
 850                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 851                                     zone, net))
 852                         goto out;
 853
 854         smp_wmb();
 855         /* The caller holds a reference to this object */
 856         atomic_set(&ct->ct_general.use, 2);
 857         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 858         nf_conntrack_double_unlock(hash, reply_hash);
 859         NF_CT_STAT_INC(net, insert);
 860         local_bh_enable();
 861         return 0;
 862
 863 out:
 864         nf_conntrack_double_unlock(hash, reply_hash);
 865         local_bh_enable();
 866         return -EEXIST;
 867 }
 868 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 869
 870 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
 871                     unsigned int bytes)
 872 {
 873         struct nf_conn_acct *acct;
 874
 875         acct = nf_conn_acct_find(ct);
 876         if (acct) {
 877                 struct nf_conn_counter *counter = acct->counter;
 878
 879                 atomic64_add(packets, &counter[dir].packets);
 880                 atomic64_add(bytes, &counter[dir].bytes);
 881         }
 882 }
 883 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
 884
 885 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 886                              const struct nf_conn *loser_ct)
 887 {
 888         struct nf_conn_acct *acct;
 889
 890         acct = nf_conn_acct_find(loser_ct);
 891         if (acct) {
 892                 struct nf_conn_counter *counter = acct->counter;
 893                 unsigned int bytes;
 894
 895                 /* u32 should be fine since we must have seen one packet. */
 896                 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
 897                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
 898         }
 899 }
 900
 901 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
 902 {
 903         struct nf_conn_tstamp *tstamp;
 904
 905         atomic_inc(&ct->ct_general.use);
 906         ct->status |= IPS_CONFIRMED;
 907
 908         /* set conntrack timestamp, if enabled. */
 909         tstamp = nf_conn_tstamp_find(ct);
 910         if (tstamp)
 911                 tstamp->start = ktime_get_real_ns();
 912 }
 913
 914 /* caller must hold locks to prevent concurrent changes */
 915 static int __nf_ct_resolve_clash(struct sk_buff *skb,
 916                                  struct nf_conntrack_tuple_hash *h)
 917 {
 918         /* This is the conntrack entry already in hashes that won race. */
 919         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 920         enum ip_conntrack_info ctinfo;
 921         struct nf_conn *loser_ct;
 922
 923         loser_ct = nf_ct_get(skb, &ctinfo);
 924
 925         if (nf_ct_is_dying(ct))
 926                 return NF_DROP;
 927
 928         if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
 929             nf_ct_match(ct, loser_ct)) {
 930                 struct net *net = nf_ct_net(ct);
 931
 932                 nf_conntrack_get(&ct->ct_general);
 933
 934                 nf_ct_acct_merge(ct, ctinfo, loser_ct);
 935                 nf_ct_add_to_dying_list(loser_ct);
 936                 nf_conntrack_put(&loser_ct->ct_general);
 937                 nf_ct_set(skb, ct, ctinfo);
 938
 939                 NF_CT_STAT_INC(net, clash_resolve);
 940                 return NF_ACCEPT;
 941         }
 942
 943         return NF_DROP;
 944 }
 945
 946 /**
 947  * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
 948  *
 949  * @skb: skb that causes the collision
 950  * @repl_idx: hash slot for reply direction
 951  *
 952  * Called when origin or reply direction had a clash.
 953  * The skb can be handled without packet drop provided the reply direction
 954  * is unique or there the existing entry has the identical tuple in both
 955  * directions.
 956  *
 957  * Caller must hold conntrack table locks to prevent concurrent updates.
 958  *
 959  * Returns NF_DROP if the clash could not be handled.
 960  */
 961 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
 962 {
 963         struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
 964         const struct nf_conntrack_zone *zone;
 965         struct nf_conntrack_tuple_hash *h;
 966         struct hlist_nulls_node *n;
 967         struct net *net;
 968
 969         zone = nf_ct_zone(loser_ct);
 970         net = nf_ct_net(loser_ct);
 971
 972         /* Reply direction must never result in a clash, unless both origin
 973          * and reply tuples are identical.
 974          */
 975         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
 976                 if (nf_ct_key_equal(h,
 977                                     &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 978                                     zone, net))
 979                         return __nf_ct_resolve_clash(skb, h);
 980         }
 981
 982         /* We want the clashing entry to go away real soon: 1 second timeout. */
 983         loser_ct->timeout = nfct_time_stamp + HZ;
 984
 985         /* IPS_NAT_CLASH removes the entry automatically on the first
 986          * reply.  Also prevents UDP tracker from moving the entry to
 987          * ASSURED state, i.e. the entry can always be evicted under
 988          * pressure.
 989          */
 990         loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
 991
 992         __nf_conntrack_insert_prepare(loser_ct);
 993
 994         /* fake add for ORIGINAL dir: we want lookups to only find the entry
 995          * already in the table.  This also hides the clashing entry from
 996          * ctnetlink iteration, i.e. conntrack -L won't show them.
 997          */
 998         hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 999
1000         hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
1001                                  &nf_conntrack_hash[repl_idx]);
1002
1003         NF_CT_STAT_INC(net, clash_resolve);
1004         return NF_ACCEPT;
1005 }
1006
1007 /**
1008  * nf_ct_resolve_clash - attempt to handle clash without packet drop
1009  *
1010  * @skb: skb that causes the clash
1011  * @h: tuplehash of the clashing entry already in table
1012  * @reply_hash: hash slot for reply direction
1013  *
1014  * A conntrack entry can be inserted to the connection tracking table
1015  * if there is no existing entry with an identical tuple.
1016  *
1017  * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1018  * to be dropped.  In case @skb is retransmitted, next conntrack lookup
1019  * will find the already-existing entry.
1020  *
1021  * The major problem with such packet drop is the extra delay added by
1022  * the packet loss -- it will take some time for a retransmit to occur
1023  * (or the sender to time out when waiting for a reply).
1024  *
1025  * This function attempts to handle the situation without packet drop.
1026  *
1027  * If @skb has no NAT transformation or if the colliding entries are
1028  * exactly the same, only the to-be-confirmed conntrack entry is discarded
1029  * and @skb is associated with the conntrack entry already in the table.
1030  *
1031  * Failing that, the new, unconfirmed conntrack is still added to the table
1032  * provided that the collision only occurs in the ORIGINAL direction.
1033  * The new entry will be added only in the non-clashing REPLY direction,
1034  * so packets in the ORIGINAL direction will continue to match the existing
1035  * entry.  The new entry will also have a fixed timeout so it expires --
1036  * due to the collision, it will only see reply traffic.
1037  *
1038  * Returns NF_DROP if the clash could not be resolved.
1039  */
1040 static __cold noinline int
1041 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1042                     u32 reply_hash)
1043 {
1044         /* This is the conntrack entry already in hashes that won race. */
1045         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1046         const struct nf_conntrack_l4proto *l4proto;
1047         enum ip_conntrack_info ctinfo;
1048         struct nf_conn *loser_ct;
1049         struct net *net;
1050         int ret;
1051
1052         loser_ct = nf_ct_get(skb, &ctinfo);
1053         net = nf_ct_net(loser_ct);
1054
1055         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1056         if (!l4proto->allow_clash)
1057                 goto drop;
1058
1059         ret = __nf_ct_resolve_clash(skb, h);
1060         if (ret == NF_ACCEPT)
1061                 return ret;
1062
1063         ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1064         if (ret == NF_ACCEPT)
1065                 return ret;
1066
1067 drop:
1068         nf_ct_add_to_dying_list(loser_ct);
1069         NF_CT_STAT_INC(net, drop);
1070         NF_CT_STAT_INC(net, insert_failed);
1071         return NF_DROP;
1072 }
1073
1074 /* Confirm a connection given skb; places it in hash table */
1075 int
1076 __nf_conntrack_confirm(struct sk_buff *skb)
1077 {
1078         const struct nf_conntrack_zone *zone;
1079         unsigned int hash, reply_hash;
1080         struct nf_conntrack_tuple_hash *h;
1081         struct nf_conn *ct;
1082         struct nf_conn_help *help;
1083         struct hlist_nulls_node *n;
1084         enum ip_conntrack_info ctinfo;
1085         struct net *net;
1086         unsigned int sequence;
1087         int ret = NF_DROP;
1088
1089         ct = nf_ct_get(skb, &ctinfo);
1090         net = nf_ct_net(ct);
1091
1092         /* ipt_REJECT uses nf_conntrack_attach to attach related
1093            ICMP/TCP RST packets in other direction.  Actual packet
1094            which created connection will be IP_CT_NEW or for an
1095            expected connection, IP_CT_RELATED. */
1096         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1097                 return NF_ACCEPT;
1098
1099         zone = nf_ct_zone(ct);
1100         local_bh_disable();
1101
1102         do {
1103                 sequence = read_seqcount_begin(&nf_conntrack_generation);
1104                 /* reuse the hash saved before */
1105                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1106                 hash = scale_hash(hash);
1107                 reply_hash = hash_conntrack(net,
1108                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
1109
1110         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1111
1112         /* We're not in hash table, and we refuse to set up related
1113          * connections for unconfirmed conns.  But packet copies and
1114          * REJECT will give spurious warnings here.
1115          */
1116
1117         /* Another skb with the same unconfirmed conntrack may
1118          * win the race. This may happen for bridge(br_flood)
1119          * or broadcast/multicast packets do skb_clone with
1120          * unconfirmed conntrack.
1121          */
1122         if (unlikely(nf_ct_is_confirmed(ct))) {
1123                 WARN_ON_ONCE(1);
1124                 nf_conntrack_double_unlock(hash, reply_hash);
1125                 local_bh_enable();
1126                 return NF_DROP;
1127         }
1128
1129         pr_debug("Confirming conntrack %p\n", ct);
1130         /* We have to check the DYING flag after unlink to prevent
1131          * a race against nf_ct_get_next_corpse() possibly called from
1132          * user context, else we insert an already 'dead' hash, blocking
1133          * further use of that particular connection -JM.
1134          */
1135         nf_ct_del_from_dying_or_unconfirmed_list(ct);
1136
1137         if (unlikely(nf_ct_is_dying(ct))) {
1138                 nf_ct_add_to_dying_list(ct);
1139                 NF_CT_STAT_INC(net, insert_failed);
1140                 goto dying;
1141         }
1142
1143         /* See if there's one in the list already, including reverse:
1144            NAT could have grabbed it without realizing, since we're
1145            not in the hash.  If there is, we lost race. */
1146         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
1147                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1148                                     zone, net))
1149                         goto out;
1150
1151         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
1152                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1153                                     zone, net))
1154                         goto out;
1155
1156         /* Timer relative to confirmation time, not original
1157            setting time, otherwise we'd get timer wrap in
1158            weird delay cases. */
1159         ct->timeout += nfct_time_stamp;
1160
1161         __nf_conntrack_insert_prepare(ct);
1162
1163         /* Since the lookup is lockless, hash insertion must be done after
1164          * starting the timer and setting the CONFIRMED bit. The RCU barriers
1165          * guarantee that no other CPU can find the conntrack before the above
1166          * stores are visible.
1167          */
1168         __nf_conntrack_hash_insert(ct, hash, reply_hash);
1169         nf_conntrack_double_unlock(hash, reply_hash);
1170         local_bh_enable();
1171
1172         help = nfct_help(ct);
1173         if (help && help->helper)
1174                 nf_conntrack_event_cache(IPCT_HELPER, ct);
1175
1176         nf_conntrack_event_cache(master_ct(ct) ?
1177                                  IPCT_RELATED : IPCT_NEW, ct);
1178         return NF_ACCEPT;
1179
1180 out:
1181         ret = nf_ct_resolve_clash(skb, h, reply_hash);
1182 dying:
1183         nf_conntrack_double_unlock(hash, reply_hash);
1184         local_bh_enable();
1185         return ret;
1186 }
1187 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1188
1189 /* Returns true if a connection correspondings to the tuple (required
1190    for NAT). */
1191 int
1192 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1193                          const struct nf_conn *ignored_conntrack)
1194 {
1195         struct net *net = nf_ct_net(ignored_conntrack);
1196         const struct nf_conntrack_zone *zone;
1197         struct nf_conntrack_tuple_hash *h;
1198         struct hlist_nulls_head *ct_hash;
1199         unsigned int hash, hsize;
1200         struct hlist_nulls_node *n;
1201         struct nf_conn *ct;
1202
1203         zone = nf_ct_zone(ignored_conntrack);
1204
1205         rcu_read_lock();
1206  begin:
1207         nf_conntrack_get_ht(&ct_hash, &hsize);
1208         hash = __hash_conntrack(net, tuple, hsize);
1209
1210         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1211                 ct = nf_ct_tuplehash_to_ctrack(h);
1212
1213                 if (ct == ignored_conntrack)
1214                         continue;
1215
1216                 if (nf_ct_is_expired(ct)) {
1217                         nf_ct_gc_expired(ct);
1218                         continue;
1219                 }
1220
1221                 if (nf_ct_key_equal(h, tuple, zone, net)) {
1222                         /* Tuple is taken already, so caller will need to find
1223                          * a new source port to use.
1224                          *
1225                          * Only exception:
1226                          * If the *original tuples* are identical, then both
1227                          * conntracks refer to the same flow.
1228                          * This is a rare situation, it can occur e.g. when
1229                          * more than one UDP packet is sent from same socket
1230                          * in different threads.
1231                          *
1232                          * Let nf_ct_resolve_clash() deal with this later.
1233                          */
1234                         if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1235                                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
1236                                               nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL))
1237                                 continue;
1238
1239                         NF_CT_STAT_INC_ATOMIC(net, found);
1240                         rcu_read_unlock();
1241                         return 1;
1242                 }
1243         }
1244
1245         if (get_nulls_value(n) != hash) {
1246                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1247                 goto begin;
1248         }
1249
1250         rcu_read_unlock();
1251
1252         return 0;
1253 }
1254 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1255
1256 #define NF_CT_EVICTION_RANGE    8
1257
1258 /* There's a small race here where we may free a just-assured
1259    connection.  Too bad: we're in trouble anyway. */
1260 static unsigned int early_drop_list(struct net *net,
1261                                     struct hlist_nulls_head *head)
1262 {
1263         struct nf_conntrack_tuple_hash *h;
1264         struct hlist_nulls_node *n;
1265         unsigned int drops = 0;
1266         struct nf_conn *tmp;
1267
1268         hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1269                 tmp = nf_ct_tuplehash_to_ctrack(h);
1270
1271                 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1272                         continue;
1273
1274                 if (nf_ct_is_expired(tmp)) {
1275                         nf_ct_gc_expired(tmp);
1276                         continue;
1277                 }
1278
1279                 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1280                     !net_eq(nf_ct_net(tmp), net) ||
1281                     nf_ct_is_dying(tmp))
1282                         continue;
1283
1284                 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1285                         continue;
1286
1287                 /* kill only if still in same netns -- might have moved due to
1288                  * SLAB_TYPESAFE_BY_RCU rules.
1289                  *
1290                  * We steal the timer reference.  If that fails timer has
1291                  * already fired or someone else deleted it. Just drop ref
1292                  * and move to next entry.
1293                  */
1294                 if (net_eq(nf_ct_net(tmp), net) &&
1295                     nf_ct_is_confirmed(tmp) &&
1296                     nf_ct_delete(tmp, 0, 0))
1297                         drops++;
1298
1299                 nf_ct_put(tmp);
1300         }
1301
1302         return drops;
1303 }
1304
1305 static noinline int early_drop(struct net *net, unsigned int hash)
1306 {
1307         unsigned int i, bucket;
1308
1309         for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1310                 struct hlist_nulls_head *ct_hash;
1311                 unsigned int hsize, drops;
1312
1313                 rcu_read_lock();
1314                 nf_conntrack_get_ht(&ct_hash, &hsize);
1315                 if (!i)
1316                         bucket = reciprocal_scale(hash, hsize);
1317                 else
1318                         bucket = (bucket + 1) % hsize;
1319
1320                 drops = early_drop_list(net, &ct_hash[bucket]);
1321                 rcu_read_unlock();
1322
1323                 if (drops) {
1324                         NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1325                         return true;
1326                 }
1327         }
1328
1329         return false;
1330 }
1331
1332 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1333 {
1334         return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1335 }
1336
1337 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1338 {
1339         const struct nf_conntrack_l4proto *l4proto;
1340
1341         if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1342                 return true;
1343
1344         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1345         if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1346                 return true;
1347
1348         return false;
1349 }
1350
1351 static void gc_worker(struct work_struct *work)
1352 {
1353         unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
1354         unsigned int i, goal, buckets = 0, expired_count = 0;
1355         unsigned int nf_conntrack_max95 = 0;
1356         struct conntrack_gc_work *gc_work;
1357         unsigned int ratio, scanned = 0;
1358         unsigned long next_run;
1359
1360         gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1361
1362         goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
1363         i = gc_work->last_bucket;
1364         if (gc_work->early_drop)
1365                 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1366
1367         do {
1368                 struct nf_conntrack_tuple_hash *h;
1369                 struct hlist_nulls_head *ct_hash;
1370                 struct hlist_nulls_node *n;
1371                 unsigned int hashsz;
1372                 struct nf_conn *tmp;
1373
1374                 i++;
1375                 rcu_read_lock();
1376
1377                 nf_conntrack_get_ht(&ct_hash, &hashsz);
1378                 if (i >= hashsz)
1379                         i = 0;
1380
1381                 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1382                         struct nf_conntrack_net *cnet;
1383                         struct net *net;
1384
1385                         tmp = nf_ct_tuplehash_to_ctrack(h);
1386
1387                         scanned++;
1388                         if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1389                                 nf_ct_offload_timeout(tmp);
1390                                 continue;
1391                         }
1392
1393                         if (nf_ct_is_expired(tmp)) {
1394                                 nf_ct_gc_expired(tmp);
1395                                 expired_count++;
1396                                 continue;
1397                         }
1398
1399                         if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1400                                 continue;
1401
1402                         net = nf_ct_net(tmp);
1403                         cnet = nf_ct_pernet(net);
1404                         if (atomic_read(&cnet->count) < nf_conntrack_max95)
1405                                 continue;
1406
1407                         /* need to take reference to avoid possible races */
1408                         if (!atomic_inc_not_zero(&tmp->ct_general.use))
1409                                 continue;
1410
1411                         if (gc_worker_skip_ct(tmp)) {
1412                                 nf_ct_put(tmp);
1413                                 continue;
1414                         }
1415
1416                         if (gc_worker_can_early_drop(tmp))
1417                                 nf_ct_kill(tmp);
1418
1419                         nf_ct_put(tmp);
1420                 }
1421
1422                 /* could check get_nulls_value() here and restart if ct
1423                  * was moved to another chain.  But given gc is best-effort
1424                  * we will just continue with next hash slot.
1425                  */
1426                 rcu_read_unlock();
1427                 cond_resched();
1428         } while (++buckets < goal);
1429
1430         if (gc_work->exiting)
1431                 return;
1432
1433         /*
1434          * Eviction will normally happen from the packet path, and not
1435          * from this gc worker.
1436          *
1437          * This worker is only here to reap expired entries when system went
1438          * idle after a busy period.
1439          *
1440          * The heuristics below are supposed to balance conflicting goals:
1441          *
1442          * 1. Minimize time until we notice a stale entry
1443          * 2. Maximize scan intervals to not waste cycles
1444          *
1445          * Normally, expire ratio will be close to 0.
1446          *
1447          * As soon as a sizeable fraction of the entries have expired
1448          * increase scan frequency.
1449          */
1450         ratio = scanned ? expired_count * 100 / scanned : 0;
1451         if (ratio > GC_EVICT_RATIO) {
1452                 gc_work->next_gc_run = min_interval;
1453         } else {
1454                 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1455
1456                 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1457
1458                 gc_work->next_gc_run += min_interval;
1459                 if (gc_work->next_gc_run > max)
1460                         gc_work->next_gc_run = max;
1461         }
1462
1463         next_run = gc_work->next_gc_run;
1464         gc_work->last_bucket = i;
1465         gc_work->early_drop = false;
1466         queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1467 }
1468
1469 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1470 {
1471         INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
1472         gc_work->next_gc_run = HZ;
1473         gc_work->exiting = false;
1474 }
1475
1476 static struct nf_conn *
1477 __nf_conntrack_alloc(struct net *net,
1478                      const struct nf_conntrack_zone *zone,
1479                      const struct nf_conntrack_tuple *orig,
1480                      const struct nf_conntrack_tuple *repl,
1481                      gfp_t gfp, u32 hash)
1482 {
1483         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
1484         unsigned int ct_count;
1485         struct nf_conn *ct;
1486
1487         /* We don't want any race condition at early drop stage */
1488         ct_count = atomic_inc_return(&cnet->count);
1489
1490         if (nf_conntrack_max && unlikely(ct_count > nf_conntrack_max)) {
1491                 if (!early_drop(net, hash)) {
1492                         if (!conntrack_gc_work.early_drop)
1493                                 conntrack_gc_work.early_drop = true;
1494                         atomic_dec(&cnet->count);
1495                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1496                         return ERR_PTR(-ENOMEM);
1497                 }
1498         }
1499
1500         /*
1501          * Do not use kmem_cache_zalloc(), as this cache uses
1502          * SLAB_TYPESAFE_BY_RCU.
1503          */
1504         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1505         if (ct == NULL)
1506                 goto out;
1507
1508         spin_lock_init(&ct->lock);
1509         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1510         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1511         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1512         /* save hash for reusing when confirming */
1513         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1514         ct->status = 0;
1515         ct->timeout = 0;
1516         write_pnet(&ct->ct_net, net);
1517         memset(&ct->__nfct_init_offset, 0,
1518                offsetof(struct nf_conn, proto) -
1519                offsetof(struct nf_conn, __nfct_init_offset));
1520
1521         nf_ct_zone_add(ct, zone);
1522
1523         /* Because we use RCU lookups, we set ct_general.use to zero before
1524          * this is inserted in any list.
1525          */
1526         atomic_set(&ct->ct_general.use, 0);
1527         return ct;
1528 out:
1529         atomic_dec(&cnet->count);
1530         return ERR_PTR(-ENOMEM);
1531 }
1532
1533 struct nf_conn *nf_conntrack_alloc(struct net *net,
1534                                    const struct nf_conntrack_zone *zone,
1535                                    const struct nf_conntrack_tuple *orig,
1536                                    const struct nf_conntrack_tuple *repl,
1537                                    gfp_t gfp)
1538 {
1539         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1540 }
1541 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1542
1543 void nf_conntrack_free(struct nf_conn *ct)
1544 {
1545         struct net *net = nf_ct_net(ct);
1546         struct nf_conntrack_net *cnet;
1547
1548         /* A freed object has refcnt == 0, that's
1549          * the golden rule for SLAB_TYPESAFE_BY_RCU
1550          */
1551         WARN_ON(atomic_read(&ct->ct_general.use) != 0);
1552
1553         nf_ct_ext_destroy(ct);
1554         kmem_cache_free(nf_conntrack_cachep, ct);
1555         cnet = nf_ct_pernet(net);
1556
1557         smp_mb__before_atomic();
1558         atomic_dec(&cnet->count);
1559 }
1560 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1561
1562
1563 /* Allocate a new conntrack: we return -ENOMEM if classification
1564    failed due to stress.  Otherwise it really is unclassifiable. */
1565 static noinline struct nf_conntrack_tuple_hash *
1566 init_conntrack(struct net *net, struct nf_conn *tmpl,
1567                const struct nf_conntrack_tuple *tuple,
1568                struct sk_buff *skb,
1569                unsigned int dataoff, u32 hash)
1570 {
1571         struct nf_conn *ct;
1572         struct nf_conn_help *help;
1573         struct nf_conntrack_tuple repl_tuple;
1574         struct nf_conntrack_ecache *ecache;
1575         struct nf_conntrack_expect *exp = NULL;
1576         const struct nf_conntrack_zone *zone;
1577         struct nf_conn_timeout *timeout_ext;
1578         struct nf_conntrack_zone tmp;
1579         struct nf_conntrack_net *cnet;
1580
1581         if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1582                 pr_debug("Can't invert tuple.\n");
1583                 return NULL;
1584         }
1585
1586         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1587         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1588                                   hash);
1589         if (IS_ERR(ct))
1590                 return (struct nf_conntrack_tuple_hash *)ct;
1591
1592         if (!nf_ct_add_synproxy(ct, tmpl)) {
1593                 nf_conntrack_free(ct);
1594                 return ERR_PTR(-ENOMEM);
1595         }
1596
1597         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1598
1599         if (timeout_ext)
1600                 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1601                                       GFP_ATOMIC);
1602
1603         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1604         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1605         nf_ct_labels_ext_add(ct);
1606
1607         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1608         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1609                                  ecache ? ecache->expmask : 0,
1610                              GFP_ATOMIC);
1611
1612         local_bh_disable();
1613         cnet = nf_ct_pernet(net);
1614         if (cnet->expect_count) {
1615                 spin_lock(&nf_conntrack_expect_lock);
1616                 exp = nf_ct_find_expectation(net, zone, tuple);
1617                 if (exp) {
1618                         pr_debug("expectation arrives ct=%p exp=%p\n",
1619                                  ct, exp);
1620                         /* Welcome, Mr. Bond.  We've been expecting you... */
1621                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
1622                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1623                         ct->master = exp->master;
1624                         if (exp->helper) {
1625                                 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1626                                 if (help)
1627                                         rcu_assign_pointer(help->helper, exp->helper);
1628                         }
1629
1630 #ifdef CONFIG_NF_CONNTRACK_MARK
1631                         ct->mark = exp->master->mark;
1632 #endif
1633 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1634                         ct->secmark = exp->master->secmark;
1635 #endif
1636                         NF_CT_STAT_INC(net, expect_new);
1637                 }
1638                 spin_unlock(&nf_conntrack_expect_lock);
1639         }
1640         if (!exp)
1641                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1642
1643         /* Now it is inserted into the unconfirmed list, bump refcount */
1644         nf_conntrack_get(&ct->ct_general);
1645         nf_ct_add_to_unconfirmed_list(ct);
1646
1647         local_bh_enable();
1648
1649         if (exp) {
1650                 if (exp->expectfn)
1651                         exp->expectfn(ct, exp);
1652                 nf_ct_expect_put(exp);
1653         }
1654
1655         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1656 }
1657
1658 /* On success, returns 0, sets skb->_nfct | ctinfo */
1659 static int
1660 resolve_normal_ct(struct nf_conn *tmpl,
1661                   struct sk_buff *skb,
1662                   unsigned int dataoff,
1663                   u_int8_t protonum,
1664                   const struct nf_hook_state *state)
1665 {
1666         const struct nf_conntrack_zone *zone;
1667         struct nf_conntrack_tuple tuple;
1668         struct nf_conntrack_tuple_hash *h;
1669         enum ip_conntrack_info ctinfo;
1670         struct nf_conntrack_zone tmp;
1671         struct nf_conn *ct;
1672         u32 hash;
1673
1674         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1675                              dataoff, state->pf, protonum, state->net,
1676                              &tuple)) {
1677                 pr_debug("Can't get tuple\n");
1678                 return 0;
1679         }
1680
1681         /* look for tuple match */
1682         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1683         hash = hash_conntrack_raw(&tuple, state->net);
1684         h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1685         if (!h) {
1686                 h = init_conntrack(state->net, tmpl, &tuple,
1687                                    skb, dataoff, hash);
1688                 if (!h)
1689                         return 0;
1690                 if (IS_ERR(h))
1691                         return PTR_ERR(h);
1692         }
1693         ct = nf_ct_tuplehash_to_ctrack(h);
1694
1695         /* It exists; we have (non-exclusive) reference. */
1696         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1697                 ctinfo = IP_CT_ESTABLISHED_REPLY;
1698         } else {
1699                 /* Once we've had two way comms, always ESTABLISHED. */
1700                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1701                         pr_debug("normal packet for %p\n", ct);
1702                         ctinfo = IP_CT_ESTABLISHED;
1703                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1704                         pr_debug("related packet for %p\n", ct);
1705                         ctinfo = IP_CT_RELATED;
1706                 } else {
1707                         pr_debug("new packet for %p\n", ct);
1708                         ctinfo = IP_CT_NEW;
1709                 }
1710         }
1711         nf_ct_set(skb, ct, ctinfo);
1712         return 0;
1713 }
1714
1715 /*
1716  * icmp packets need special treatment to handle error messages that are
1717  * related to a connection.
1718  *
1719  * Callers need to check if skb has a conntrack assigned when this
1720  * helper returns; in such case skb belongs to an already known connection.
1721  */
1722 static unsigned int __cold
1723 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1724                          struct sk_buff *skb,
1725                          unsigned int dataoff,
1726                          u8 protonum,
1727                          const struct nf_hook_state *state)
1728 {
1729         int ret;
1730
1731         if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1732                 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1733 #if IS_ENABLED(CONFIG_IPV6)
1734         else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1735                 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1736 #endif
1737         else
1738                 return NF_ACCEPT;
1739
1740         if (ret <= 0)
1741                 NF_CT_STAT_INC_ATOMIC(state->net, error);
1742
1743         return ret;
1744 }
1745
1746 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1747                           enum ip_conntrack_info ctinfo)
1748 {
1749         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1750
1751         if (!timeout)
1752                 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1753
1754         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1755         return NF_ACCEPT;
1756 }
1757
1758 /* Returns verdict for packet, or -1 for invalid. */
1759 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1760                                       struct sk_buff *skb,
1761                                       unsigned int dataoff,
1762                                       enum ip_conntrack_info ctinfo,
1763                                       const struct nf_hook_state *state)
1764 {
1765         switch (nf_ct_protonum(ct)) {
1766         case IPPROTO_TCP:
1767                 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1768                                                ctinfo, state);
1769         case IPPROTO_UDP:
1770                 return nf_conntrack_udp_packet(ct, skb, dataoff,
1771                                                ctinfo, state);
1772         case IPPROTO_ICMP:
1773                 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1774 #if IS_ENABLED(CONFIG_IPV6)
1775         case IPPROTO_ICMPV6:
1776                 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1777 #endif
1778 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1779         case IPPROTO_UDPLITE:
1780                 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1781                                                    ctinfo, state);
1782 #endif
1783 #ifdef CONFIG_NF_CT_PROTO_SCTP
1784         case IPPROTO_SCTP:
1785                 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1786                                                 ctinfo, state);
1787 #endif
1788 #ifdef CONFIG_NF_CT_PROTO_DCCP
1789         case IPPROTO_DCCP:
1790                 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1791                                                 ctinfo, state);
1792 #endif
1793 #ifdef CONFIG_NF_CT_PROTO_GRE
1794         case IPPROTO_GRE:
1795                 return nf_conntrack_gre_packet(ct, skb, dataoff,
1796                                                ctinfo, state);
1797 #endif
1798         }
1799
1800         return generic_packet(ct, skb, ctinfo);
1801 }
1802
1803 unsigned int
1804 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1805 {
1806         enum ip_conntrack_info ctinfo;
1807         struct nf_conn *ct, *tmpl;
1808         u_int8_t protonum;
1809         int dataoff, ret;
1810
1811         tmpl = nf_ct_get(skb, &ctinfo);
1812         if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1813                 /* Previously seen (loopback or untracked)?  Ignore. */
1814                 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1815                      ctinfo == IP_CT_UNTRACKED)
1816                         return NF_ACCEPT;
1817                 skb->_nfct = 0;
1818         }
1819
1820         /* rcu_read_lock()ed by nf_hook_thresh */
1821         dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1822         if (dataoff <= 0) {
1823                 pr_debug("not prepared to track yet or error occurred\n");
1824                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1825                 ret = NF_ACCEPT;
1826                 goto out;
1827         }
1828
1829         if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1830                 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1831                                                protonum, state);
1832                 if (ret <= 0) {
1833                         ret = -ret;
1834                         goto out;
1835                 }
1836                 /* ICMP[v6] protocol trackers may assign one conntrack. */
1837                 if (skb->_nfct)
1838                         goto out;
1839         }
1840 repeat:
1841         ret = resolve_normal_ct(tmpl, skb, dataoff,
1842                                 protonum, state);
1843         if (ret < 0) {
1844                 /* Too stressed to deal. */
1845                 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1846                 ret = NF_DROP;
1847                 goto out;
1848         }
1849
1850         ct = nf_ct_get(skb, &ctinfo);
1851         if (!ct) {
1852                 /* Not valid part of a connection */
1853                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1854                 ret = NF_ACCEPT;
1855                 goto out;
1856         }
1857
1858         ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
1859         if (ret <= 0) {
1860                 /* Invalid: inverse of the return code tells
1861                  * the netfilter core what to do */
1862                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1863                 nf_conntrack_put(&ct->ct_general);
1864                 skb->_nfct = 0;
1865                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1866                 if (ret == -NF_DROP)
1867                         NF_CT_STAT_INC_ATOMIC(state->net, drop);
1868                 /* Special case: TCP tracker reports an attempt to reopen a
1869                  * closed/aborted connection. We have to go back and create a
1870                  * fresh conntrack.
1871                  */
1872                 if (ret == -NF_REPEAT)
1873                         goto repeat;
1874                 ret = -ret;
1875                 goto out;
1876         }
1877
1878         if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
1879             !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1880                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1881 out:
1882         if (tmpl)
1883                 nf_ct_put(tmpl);
1884
1885         return ret;
1886 }
1887 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1888
1889 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1890    implicitly racy: see __nf_conntrack_confirm */
1891 void nf_conntrack_alter_reply(struct nf_conn *ct,
1892                               const struct nf_conntrack_tuple *newreply)
1893 {
1894         struct nf_conn_help *help = nfct_help(ct);
1895
1896         /* Should be unconfirmed, so not in hash table yet */
1897         WARN_ON(nf_ct_is_confirmed(ct));
1898
1899         pr_debug("Altering reply tuple of %p to ", ct);
1900         nf_ct_dump_tuple(newreply);
1901
1902         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1903         if (ct->master || (help && !hlist_empty(&help->expectations)))
1904                 return;
1905
1906         rcu_read_lock();
1907         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1908         rcu_read_unlock();
1909 }
1910 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1911
1912 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1913 void __nf_ct_refresh_acct(struct nf_conn *ct,
1914                           enum ip_conntrack_info ctinfo,
1915                           const struct sk_buff *skb,
1916                           u32 extra_jiffies,
1917                           bool do_acct)
1918 {
1919         /* Only update if this is not a fixed timeout */
1920         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1921                 goto acct;
1922
1923         /* If not in hash table, timer will not be active yet */
1924         if (nf_ct_is_confirmed(ct))
1925                 extra_jiffies += nfct_time_stamp;
1926
1927         if (READ_ONCE(ct->timeout) != extra_jiffies)
1928                 WRITE_ONCE(ct->timeout, extra_jiffies);
1929 acct:
1930         if (do_acct)
1931                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1932 }
1933 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1934
1935 bool nf_ct_kill_acct(struct nf_conn *ct,
1936                      enum ip_conntrack_info ctinfo,
1937                      const struct sk_buff *skb)
1938 {
1939         nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1940
1941         return nf_ct_delete(ct, 0, 0);
1942 }
1943 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1944
1945 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1946
1947 #include <linux/netfilter/nfnetlink.h>
1948 #include <linux/netfilter/nfnetlink_conntrack.h>
1949 #include <linux/mutex.h>
1950
1951 /* Generic function for tcp/udp/sctp/dccp and alike. */
1952 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1953                                const struct nf_conntrack_tuple *tuple)
1954 {
1955         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1956             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1957                 goto nla_put_failure;
1958         return 0;
1959
1960 nla_put_failure:
1961         return -1;
1962 }
1963 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1964
1965 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1966         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1967         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1968 };
1969 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1970
1971 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1972                                struct nf_conntrack_tuple *t,
1973                                u_int32_t flags)
1974 {
1975         if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
1976                 if (!tb[CTA_PROTO_SRC_PORT])
1977                         return -EINVAL;
1978
1979                 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1980         }
1981
1982         if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
1983                 if (!tb[CTA_PROTO_DST_PORT])
1984                         return -EINVAL;
1985
1986                 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1987         }
1988
1989         return 0;
1990 }
1991 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1992
1993 unsigned int nf_ct_port_nlattr_tuple_size(void)
1994 {
1995         static unsigned int size __read_mostly;
1996
1997         if (!size)
1998                 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1999
2000         return size;
2001 }
2002 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
2003 #endif
2004
2005 /* Used by ipt_REJECT and ip6t_REJECT. */
2006 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
2007 {
2008         struct nf_conn *ct;
2009         enum ip_conntrack_info ctinfo;
2010
2011         /* This ICMP is in reverse direction to the packet which caused it */
2012         ct = nf_ct_get(skb, &ctinfo);
2013         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2014                 ctinfo = IP_CT_RELATED_REPLY;
2015         else
2016                 ctinfo = IP_CT_RELATED;
2017
2018         /* Attach to new skbuff, and increment count */
2019         nf_ct_set(nskb, ct, ctinfo);
2020         nf_conntrack_get(skb_nfct(nskb));
2021 }
2022
2023 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2024                                  struct nf_conn *ct,
2025                                  enum ip_conntrack_info ctinfo)
2026 {
2027         struct nf_conntrack_tuple_hash *h;
2028         struct nf_conntrack_tuple tuple;
2029         struct nf_nat_hook *nat_hook;
2030         unsigned int status;
2031         int dataoff;
2032         u16 l3num;
2033         u8 l4num;
2034
2035         l3num = nf_ct_l3num(ct);
2036
2037         dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2038         if (dataoff <= 0)
2039                 return -1;
2040
2041         if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2042                              l4num, net, &tuple))
2043                 return -1;
2044
2045         if (ct->status & IPS_SRC_NAT) {
2046                 memcpy(tuple.src.u3.all,
2047                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2048                        sizeof(tuple.src.u3.all));
2049                 tuple.src.u.all =
2050                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2051         }
2052
2053         if (ct->status & IPS_DST_NAT) {
2054                 memcpy(tuple.dst.u3.all,
2055                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2056                        sizeof(tuple.dst.u3.all));
2057                 tuple.dst.u.all =
2058                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2059         }
2060
2061         h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2062         if (!h)
2063                 return 0;
2064
2065         /* Store status bits of the conntrack that is clashing to re-do NAT
2066          * mangling according to what it has been done already to this packet.
2067          */
2068         status = ct->status;
2069
2070         nf_ct_put(ct);
2071         ct = nf_ct_tuplehash_to_ctrack(h);
2072         nf_ct_set(skb, ct, ctinfo);
2073
2074         nat_hook = rcu_dereference(nf_nat_hook);
2075         if (!nat_hook)
2076                 return 0;
2077
2078         if (status & IPS_SRC_NAT &&
2079             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2080                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2081                 return -1;
2082
2083         if (status & IPS_DST_NAT &&
2084             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2085                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2086                 return -1;
2087
2088         return 0;
2089 }
2090
2091 /* This packet is coming from userspace via nf_queue, complete the packet
2092  * processing after the helper invocation in nf_confirm().
2093  */
2094 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2095                                enum ip_conntrack_info ctinfo)
2096 {
2097         const struct nf_conntrack_helper *helper;
2098         const struct nf_conn_help *help;
2099         int protoff;
2100
2101         help = nfct_help(ct);
2102         if (!help)
2103                 return 0;
2104
2105         helper = rcu_dereference(help->helper);
2106         if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2107                 return 0;
2108
2109         switch (nf_ct_l3num(ct)) {
2110         case NFPROTO_IPV4:
2111                 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2112                 break;
2113 #if IS_ENABLED(CONFIG_IPV6)
2114         case NFPROTO_IPV6: {
2115                 __be16 frag_off;
2116                 u8 pnum;
2117
2118                 pnum = ipv6_hdr(skb)->nexthdr;
2119                 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2120                                            &frag_off);
2121                 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2122                         return 0;
2123                 break;
2124         }
2125 #endif
2126         default:
2127                 return 0;
2128         }
2129
2130         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2131             !nf_is_loopback_packet(skb)) {
2132                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2133                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2134                         return -1;
2135                 }
2136         }
2137
2138         /* We've seen it coming out the other side: confirm it */
2139         return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2140 }
2141
2142 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2143 {
2144         enum ip_conntrack_info ctinfo;
2145         struct nf_conn *ct;
2146         int err;
2147
2148         ct = nf_ct_get(skb, &ctinfo);
2149         if (!ct)
2150                 return 0;
2151
2152         if (!nf_ct_is_confirmed(ct)) {
2153                 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2154                 if (err < 0)
2155                         return err;
2156
2157                 ct = nf_ct_get(skb, &ctinfo);
2158         }
2159
2160         return nf_confirm_cthelper(skb, ct, ctinfo);
2161 }
2162
2163 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2164                                        const struct sk_buff *skb)
2165 {
2166         const struct nf_conntrack_tuple *src_tuple;
2167         const struct nf_conntrack_tuple_hash *hash;
2168         struct nf_conntrack_tuple srctuple;
2169         enum ip_conntrack_info ctinfo;
2170         struct nf_conn *ct;
2171
2172         ct = nf_ct_get(skb, &ctinfo);
2173         if (ct) {
2174                 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2175                 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2176                 return true;
2177         }
2178
2179         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2180                                NFPROTO_IPV4, dev_net(skb->dev),
2181                                &srctuple))
2182                 return false;
2183
2184         hash = nf_conntrack_find_get(dev_net(skb->dev),
2185                                      &nf_ct_zone_dflt,
2186                                      &srctuple);
2187         if (!hash)
2188                 return false;
2189
2190         ct = nf_ct_tuplehash_to_ctrack(hash);
2191         src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2192         memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2193         nf_ct_put(ct);
2194
2195         return true;
2196 }
2197
2198 /* Bring out ya dead! */
2199 static struct nf_conn *
2200 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2201                 void *data, unsigned int *bucket)
2202 {
2203         struct nf_conntrack_tuple_hash *h;
2204         struct nf_conn *ct;
2205         struct hlist_nulls_node *n;
2206         spinlock_t *lockp;
2207
2208         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2209                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2210                 local_bh_disable();
2211                 nf_conntrack_lock(lockp);
2212                 if (*bucket < nf_conntrack_htable_size) {
2213                         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
2214                                 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2215                                         continue;
2216                                 /* All nf_conn objects are added to hash table twice, one
2217                                  * for original direction tuple, once for the reply tuple.
2218                                  *
2219                                  * Exception: In the IPS_NAT_CLASH case, only the reply
2220                                  * tuple is added (the original tuple already existed for
2221                                  * a different object).
2222                                  *
2223                                  * We only need to call the iterator once for each
2224                                  * conntrack, so we just use the 'reply' direction
2225                                  * tuple while iterating.
2226                                  */
2227                                 ct = nf_ct_tuplehash_to_ctrack(h);
2228                                 if (iter(ct, data))
2229                                         goto found;
2230                         }
2231                 }
2232                 spin_unlock(lockp);
2233                 local_bh_enable();
2234                 cond_resched();
2235         }
2236
2237         return NULL;
2238 found:
2239         atomic_inc(&ct->ct_general.use);
2240         spin_unlock(lockp);
2241         local_bh_enable();
2242         return ct;
2243 }
2244
2245 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2246                                   void *data, u32 portid, int report)
2247 {
2248         unsigned int bucket = 0, sequence;
2249         struct nf_conn *ct;
2250
2251         might_sleep();
2252
2253         for (;;) {
2254                 sequence = read_seqcount_begin(&nf_conntrack_generation);
2255
2256                 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
2257                         /* Time to push up daises... */
2258
2259                         nf_ct_delete(ct, portid, report);
2260                         nf_ct_put(ct);
2261                         cond_resched();
2262                 }
2263
2264                 if (!read_seqcount_retry(&nf_conntrack_generation, sequence))
2265                         break;
2266                 bucket = 0;
2267         }
2268 }
2269
2270 struct iter_data {
2271         int (*iter)(struct nf_conn *i, void *data);
2272         void *data;
2273         struct net *net;
2274 };
2275
2276 static int iter_net_only(struct nf_conn *i, void *data)
2277 {
2278         struct iter_data *d = data;
2279
2280         if (!net_eq(d->net, nf_ct_net(i)))
2281                 return 0;
2282
2283         return d->iter(i, d->data);
2284 }
2285
2286 static void
2287 __nf_ct_unconfirmed_destroy(struct net *net)
2288 {
2289         int cpu;
2290
2291         for_each_possible_cpu(cpu) {
2292                 struct nf_conntrack_tuple_hash *h;
2293                 struct hlist_nulls_node *n;
2294                 struct ct_pcpu *pcpu;
2295
2296                 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2297
2298                 spin_lock_bh(&pcpu->lock);
2299                 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
2300                         struct nf_conn *ct;
2301
2302                         ct = nf_ct_tuplehash_to_ctrack(h);
2303
2304                         /* we cannot call iter() on unconfirmed list, the
2305                          * owning cpu can reallocate ct->ext at any time.
2306                          */
2307                         set_bit(IPS_DYING_BIT, &ct->status);
2308                 }
2309                 spin_unlock_bh(&pcpu->lock);
2310                 cond_resched();
2311         }
2312 }
2313
2314 void nf_ct_unconfirmed_destroy(struct net *net)
2315 {
2316         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2317
2318         might_sleep();
2319
2320         if (atomic_read(&cnet->count) > 0) {
2321                 __nf_ct_unconfirmed_destroy(net);
2322                 nf_queue_nf_hook_drop(net);
2323                 synchronize_net();
2324         }
2325 }
2326 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
2327
2328 void nf_ct_iterate_cleanup_net(struct net *net,
2329                                int (*iter)(struct nf_conn *i, void *data),
2330                                void *data, u32 portid, int report)
2331 {
2332         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2333         struct iter_data d;
2334
2335         might_sleep();
2336
2337         if (atomic_read(&cnet->count) == 0)
2338                 return;
2339
2340         d.iter = iter;
2341         d.data = data;
2342         d.net = net;
2343
2344         nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
2345 }
2346 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2347
2348 /**
2349  * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2350  * @iter: callback to invoke for each conntrack
2351  * @data: data to pass to @iter
2352  *
2353  * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2354  * unconfirmed list as dying (so they will not be inserted into
2355  * main table).
2356  *
2357  * Can only be called in module exit path.
2358  */
2359 void
2360 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2361 {
2362         struct net *net;
2363
2364         down_read(&net_rwsem);
2365         for_each_net(net) {
2366                 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2367
2368                 if (atomic_read(&cnet->count) == 0)
2369                         continue;
2370                 __nf_ct_unconfirmed_destroy(net);
2371                 nf_queue_nf_hook_drop(net);
2372         }
2373         up_read(&net_rwsem);
2374
2375         /* Need to wait for netns cleanup worker to finish, if its
2376          * running -- it might have deleted a net namespace from
2377          * the global list, so our __nf_ct_unconfirmed_destroy() might
2378          * not have affected all namespaces.
2379          */
2380         net_ns_barrier();
2381
2382         /* a conntrack could have been unlinked from unconfirmed list
2383          * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
2384          * This makes sure its inserted into conntrack table.
2385          */
2386         synchronize_net();
2387
2388         nf_ct_iterate_cleanup(iter, data, 0, 0);
2389 }
2390 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2391
2392 static int kill_all(struct nf_conn *i, void *data)
2393 {
2394         return net_eq(nf_ct_net(i), data);
2395 }
2396
2397 void nf_conntrack_cleanup_start(void)
2398 {
2399         conntrack_gc_work.exiting = true;
2400         RCU_INIT_POINTER(ip_ct_attach, NULL);
2401 }
2402
2403 void nf_conntrack_cleanup_end(void)
2404 {
2405         RCU_INIT_POINTER(nf_ct_hook, NULL);
2406         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2407         kvfree(nf_conntrack_hash);
2408
2409         nf_conntrack_proto_fini();
2410         nf_conntrack_seqadj_fini();
2411         nf_conntrack_labels_fini();
2412         nf_conntrack_helper_fini();
2413         nf_conntrack_timeout_fini();
2414         nf_conntrack_ecache_fini();
2415         nf_conntrack_tstamp_fini();
2416         nf_conntrack_acct_fini();
2417         nf_conntrack_expect_fini();
2418
2419         kmem_cache_destroy(nf_conntrack_cachep);
2420 }
2421
2422 /*
2423  * Mishearing the voices in his head, our hero wonders how he's
2424  * supposed to kill the mall.
2425  */
2426 void nf_conntrack_cleanup_net(struct net *net)
2427 {
2428         LIST_HEAD(single);
2429
2430         list_add(&net->exit_list, &single);
2431         nf_conntrack_cleanup_net_list(&single);
2432 }
2433
2434 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2435 {
2436         int busy;
2437         struct net *net;
2438
2439         /*
2440          * This makes sure all current packets have passed through
2441          *  netfilter framework.  Roll on, two-stage module
2442          *  delete...
2443          */
2444         synchronize_net();
2445 i_see_dead_people:
2446         busy = 0;
2447         list_for_each_entry(net, net_exit_list, exit_list) {
2448                 struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2449
2450                 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
2451                 if (atomic_read(&cnet->count) != 0)
2452                         busy = 1;
2453         }
2454         if (busy) {
2455                 schedule();
2456                 goto i_see_dead_people;
2457         }
2458
2459         list_for_each_entry(net, net_exit_list, exit_list) {
2460                 nf_conntrack_proto_pernet_fini(net);
2461                 nf_conntrack_ecache_pernet_fini(net);
2462                 nf_conntrack_expect_pernet_fini(net);
2463                 free_percpu(net->ct.stat);
2464                 free_percpu(net->ct.pcpu_lists);
2465         }
2466 }
2467
2468 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2469 {
2470         struct hlist_nulls_head *hash;
2471         unsigned int nr_slots, i;
2472
2473         if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2474                 return NULL;
2475
2476         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2477         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2478
2479         hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2480
2481         if (hash && nulls)
2482                 for (i = 0; i < nr_slots; i++)
2483                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
2484
2485         return hash;
2486 }
2487 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2488
2489 int nf_conntrack_hash_resize(unsigned int hashsize)
2490 {
2491         int i, bucket;
2492         unsigned int old_size;
2493         struct hlist_nulls_head *hash, *old_hash;
2494         struct nf_conntrack_tuple_hash *h;
2495         struct nf_conn *ct;
2496
2497         if (!hashsize)
2498                 return -EINVAL;
2499
2500         hash = nf_ct_alloc_hashtable(&hashsize, 1);
2501         if (!hash)
2502                 return -ENOMEM;
2503
2504         old_size = nf_conntrack_htable_size;
2505         if (old_size == hashsize) {
2506                 kvfree(hash);
2507                 return 0;
2508         }
2509
2510         local_bh_disable();
2511         nf_conntrack_all_lock();
2512         write_seqcount_begin(&nf_conntrack_generation);
2513
2514         /* Lookups in the old hash might happen in parallel, which means we
2515          * might get false negatives during connection lookup. New connections
2516          * created because of a false negative won't make it into the hash
2517          * though since that required taking the locks.
2518          */
2519
2520         for (i = 0; i < nf_conntrack_htable_size; i++) {
2521                 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2522                         h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2523                                               struct nf_conntrack_tuple_hash, hnnode);
2524                         ct = nf_ct_tuplehash_to_ctrack(h);
2525                         hlist_nulls_del_rcu(&h->hnnode);
2526                         bucket = __hash_conntrack(nf_ct_net(ct),
2527                                                   &h->tuple, hashsize);
2528                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2529                 }
2530         }
2531         old_size = nf_conntrack_htable_size;
2532         old_hash = nf_conntrack_hash;
2533
2534         nf_conntrack_hash = hash;
2535         nf_conntrack_htable_size = hashsize;
2536
2537         write_seqcount_end(&nf_conntrack_generation);
2538         nf_conntrack_all_unlock();
2539         local_bh_enable();
2540
2541         synchronize_net();
2542         kvfree(old_hash);
2543         return 0;
2544 }
2545
2546 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2547 {
2548         unsigned int hashsize;
2549         int rc;
2550
2551         if (current->nsproxy->net_ns != &init_net)
2552                 return -EOPNOTSUPP;
2553
2554         /* On boot, we can set this without any fancy locking. */
2555         if (!nf_conntrack_hash)
2556                 return param_set_uint(val, kp);
2557
2558         rc = kstrtouint(val, 0, &hashsize);
2559         if (rc)
2560                 return rc;
2561
2562         return nf_conntrack_hash_resize(hashsize);
2563 }
2564
2565 static __always_inline unsigned int total_extension_size(void)
2566 {
2567         /* remember to add new extensions below */
2568         BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
2569
2570         return sizeof(struct nf_ct_ext) +
2571                sizeof(struct nf_conn_help)
2572 #if IS_ENABLED(CONFIG_NF_NAT)
2573                 + sizeof(struct nf_conn_nat)
2574 #endif
2575                 + sizeof(struct nf_conn_seqadj)
2576                 + sizeof(struct nf_conn_acct)
2577 #ifdef CONFIG_NF_CONNTRACK_EVENTS
2578                 + sizeof(struct nf_conntrack_ecache)
2579 #endif
2580 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
2581                 + sizeof(struct nf_conn_tstamp)
2582 #endif
2583 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
2584                 + sizeof(struct nf_conn_timeout)
2585 #endif
2586 #ifdef CONFIG_NF_CONNTRACK_LABELS
2587                 + sizeof(struct nf_conn_labels)
2588 #endif
2589 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
2590                 + sizeof(struct nf_conn_synproxy)
2591 #endif
2592         ;
2593 };
2594
2595 int nf_conntrack_init_start(void)
2596 {
2597         unsigned long nr_pages = totalram_pages();
2598         int max_factor = 8;
2599         int ret = -ENOMEM;
2600         int i;
2601
2602         /* struct nf_ct_ext uses u8 to store offsets/size */
2603         BUILD_BUG_ON(total_extension_size() > 255u);
2604
2605         seqcount_spinlock_init(&nf_conntrack_generation,
2606                                &nf_conntrack_locks_all_lock);
2607
2608         for (i = 0; i < CONNTRACK_LOCKS; i++)
2609                 spin_lock_init(&nf_conntrack_locks[i]);
2610
2611         if (!nf_conntrack_htable_size) {
2612                 /* Idea from tcp.c: use 1/16384 of memory.
2613                  * On i386: 32MB machine has 512 buckets.
2614                  * >= 1GB machines have 16384 buckets.
2615                  * >= 4GB machines have 65536 buckets.
2616                  */
2617                 nf_conntrack_htable_size
2618                         = (((nr_pages << PAGE_SHIFT) / 16384)
2619                            / sizeof(struct hlist_head));
2620                 if (nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2621                         nf_conntrack_htable_size = 65536;
2622                 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2623                         nf_conntrack_htable_size = 16384;
2624                 if (nf_conntrack_htable_size < 32)
2625                         nf_conntrack_htable_size = 32;
2626
2627                 /* Use a max. factor of four by default to get the same max as
2628                  * with the old struct list_heads. When a table size is given
2629                  * we use the old value of 8 to avoid reducing the max.
2630                  * entries. */
2631                 max_factor = 4;
2632         }
2633
2634         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2635         if (!nf_conntrack_hash)
2636                 return -ENOMEM;
2637
2638         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2639
2640         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2641                                                 sizeof(struct nf_conn),
2642                                                 NFCT_INFOMASK + 1,
2643                                                 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2644         if (!nf_conntrack_cachep)
2645                 goto err_cachep;
2646
2647         ret = nf_conntrack_expect_init();
2648         if (ret < 0)
2649                 goto err_expect;
2650
2651         ret = nf_conntrack_acct_init();
2652         if (ret < 0)
2653                 goto err_acct;
2654
2655         ret = nf_conntrack_tstamp_init();
2656         if (ret < 0)
2657                 goto err_tstamp;
2658
2659         ret = nf_conntrack_ecache_init();
2660         if (ret < 0)
2661                 goto err_ecache;
2662
2663         ret = nf_conntrack_timeout_init();
2664         if (ret < 0)
2665                 goto err_timeout;
2666
2667         ret = nf_conntrack_helper_init();
2668         if (ret < 0)
2669                 goto err_helper;
2670
2671         ret = nf_conntrack_labels_init();
2672         if (ret < 0)
2673                 goto err_labels;
2674
2675         ret = nf_conntrack_seqadj_init();
2676         if (ret < 0)
2677                 goto err_seqadj;
2678
2679         ret = nf_conntrack_proto_init();
2680         if (ret < 0)
2681                 goto err_proto;
2682
2683         conntrack_gc_work_init(&conntrack_gc_work);
2684         queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2685
2686         return 0;
2687
2688 err_proto:
2689         nf_conntrack_seqadj_fini();
2690 err_seqadj:
2691         nf_conntrack_labels_fini();
2692 err_labels:
2693         nf_conntrack_helper_fini();
2694 err_helper:
2695         nf_conntrack_timeout_fini();
2696 err_timeout:
2697         nf_conntrack_ecache_fini();
2698 err_ecache:
2699         nf_conntrack_tstamp_fini();
2700 err_tstamp:
2701         nf_conntrack_acct_fini();
2702 err_acct:
2703         nf_conntrack_expect_fini();
2704 err_expect:
2705         kmem_cache_destroy(nf_conntrack_cachep);
2706 err_cachep:
2707         kvfree(nf_conntrack_hash);
2708         return ret;
2709 }
2710
2711 static struct nf_ct_hook nf_conntrack_hook = {
2712         .update         = nf_conntrack_update,
2713         .destroy        = destroy_conntrack,
2714         .get_tuple_skb  = nf_conntrack_get_tuple_skb,
2715 };
2716
2717 void nf_conntrack_init_end(void)
2718 {
2719         /* For use by REJECT target */
2720         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2721         RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2722 }
2723
2724 /*
2725  * We need to use special "null" values, not used in hash table
2726  */
2727 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
2728 #define DYING_NULLS_VAL         ((1<<30)+1)
2729
2730 int nf_conntrack_init_net(struct net *net)
2731 {
2732         struct nf_conntrack_net *cnet = nf_ct_pernet(net);
2733         int ret = -ENOMEM;
2734         int cpu;
2735
2736         BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2737         BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2738         atomic_set(&cnet->count, 0);
2739
2740         net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2741         if (!net->ct.pcpu_lists)
2742                 goto err_stat;
2743
2744         for_each_possible_cpu(cpu) {
2745                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2746
2747                 spin_lock_init(&pcpu->lock);
2748                 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2749                 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2750         }
2751
2752         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2753         if (!net->ct.stat)
2754                 goto err_pcpu_lists;
2755
2756         ret = nf_conntrack_expect_pernet_init(net);
2757         if (ret < 0)
2758                 goto err_expect;
2759
2760         nf_conntrack_acct_pernet_init(net);
2761         nf_conntrack_tstamp_pernet_init(net);
2762         nf_conntrack_ecache_pernet_init(net);
2763         nf_conntrack_helper_pernet_init(net);
2764         nf_conntrack_proto_pernet_init(net);
2765
2766         return 0;
2767
2768 err_expect:
2769         free_percpu(net->ct.stat);
2770 err_pcpu_lists:
2771         free_percpu(net->ct.pcpu_lists);
2772 err_stat:
2773         return ret;
2774 }