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_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
 660         if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
 661                 return false;
 662
 663         tstamp = nf_conn_tstamp_find(ct);
 664         if (tstamp && tstamp->stop == 0)
 665                 tstamp->stop = ktime_get_real_ns();
 666
 667         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 668                                     portid, report) < 0) {
 669                 /* destroy event was not delivered. nf_ct_put will
 670                  * be done by event cache worker on redelivery.
 671                  */
 672                 nf_ct_delete_from_lists(ct);
 673                 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
 674                 return false;
 675         }
 676
 677         nf_conntrack_ecache_work(nf_ct_net(ct));
 678         nf_ct_delete_from_lists(ct);
 679         nf_ct_put(ct);
 680         return true;
 681 }
 682 EXPORT_SYMBOL_GPL(nf_ct_delete);
 683
 684 static inline bool
 685 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 686                 const struct nf_conntrack_tuple *tuple,
 687                 const struct nf_conntrack_zone *zone,
 688                 const struct net *net)
 689 {
 690         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 691
 692         /* A conntrack can be recreated with the equal tuple,
 693          * so we need to check that the conntrack is confirmed
 694          */
 695         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 696                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 697                nf_ct_is_confirmed(ct) &&
 698                net_eq(net, nf_ct_net(ct));
 699 }
 700
 701 static inline bool
 702 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
 703 {
 704         return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 705                                  &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
 706                nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
 707                                  &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
 708                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
 709                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
 710                net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
 711 }
 712
 713 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
 714 static void nf_ct_gc_expired(struct nf_conn *ct)
 715 {
 716         if (!atomic_inc_not_zero(&ct->ct_general.use))
 717                 return;
 718
 719         if (nf_ct_should_gc(ct))
 720                 nf_ct_kill(ct);
 721
 722         nf_ct_put(ct);
 723 }
 724
 725 /*
 726  * Warning :
 727  * - Caller must take a reference on returned object
 728  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 729  */
 730 static struct nf_conntrack_tuple_hash *
 731 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 732                       const struct nf_conntrack_tuple *tuple, u32 hash)
 733 {
 734         struct nf_conntrack_tuple_hash *h;
 735         struct hlist_nulls_head *ct_hash;
 736         struct hlist_nulls_node *n;
 737         unsigned int bucket, hsize;
 738
 739 begin:
 740         nf_conntrack_get_ht(&ct_hash, &hsize);
 741         bucket = reciprocal_scale(hash, hsize);
 742
 743         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
 744                 struct nf_conn *ct;
 745
 746                 ct = nf_ct_tuplehash_to_ctrack(h);
 747                 if (nf_ct_is_expired(ct)) {
 748                         nf_ct_gc_expired(ct);
 749                         continue;
 750                 }
 751
 752                 if (nf_ct_key_equal(h, tuple, zone, net))
 753                         return h;
 754         }
 755         /*
 756          * if the nulls value we got at the end of this lookup is
 757          * not the expected one, we must restart lookup.
 758          * We probably met an item that was moved to another chain.
 759          */
 760         if (get_nulls_value(n) != bucket) {
 761                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 762                 goto begin;
 763         }
 764
 765         return NULL;
 766 }
 767
 768 /* Find a connection corresponding to a tuple. */
 769 static struct nf_conntrack_tuple_hash *
 770 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 771                         const struct nf_conntrack_tuple *tuple, u32 hash)
 772 {
 773         struct nf_conntrack_tuple_hash *h;
 774         struct nf_conn *ct;
 775
 776         rcu_read_lock();
 777
 778         h = ____nf_conntrack_find(net, zone, tuple, hash);
 779         if (h) {
 780                 /* We have a candidate that matches the tuple we're interested
 781                  * in, try to obtain a reference and re-check tuple
 782                  */
 783                 ct = nf_ct_tuplehash_to_ctrack(h);
 784                 if (likely(atomic_inc_not_zero(&ct->ct_general.use))) {
 785                         if (likely(nf_ct_key_equal(h, tuple, zone, net)))
 786                                 goto found;
 787
 788                         /* TYPESAFE_BY_RCU recycled the candidate */
 789                         nf_ct_put(ct);
 790                 }
 791
 792                 h = NULL;
 793         }
 794 found:
 795         rcu_read_unlock();
 796
 797         return h;
 798 }
 799
 800 struct nf_conntrack_tuple_hash *
 801 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 802                       const struct nf_conntrack_tuple *tuple)
 803 {
 804         return __nf_conntrack_find_get(net, zone, tuple,
 805                                        hash_conntrack_raw(tuple, net));
 806 }
 807 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 808
 809 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 810                                        unsigned int hash,
 811                                        unsigned int reply_hash)
 812 {
 813         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 814                            &nf_conntrack_hash[hash]);
 815         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 816                            &nf_conntrack_hash[reply_hash]);
 817 }
 818
 819 int
 820 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 821 {
 822         const struct nf_conntrack_zone *zone;
 823         struct net *net = nf_ct_net(ct);
 824         unsigned int hash, reply_hash;
 825         struct nf_conntrack_tuple_hash *h;
 826         struct hlist_nulls_node *n;
 827         unsigned int sequence;
 828
 829         zone = nf_ct_zone(ct);
 830
 831         local_bh_disable();
 832         do {
 833                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 834                 hash = hash_conntrack(net,
 835                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 836                 reply_hash = hash_conntrack(net,
 837                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 838         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 839
 840         /* See if there's one in the list already, including reverse */
 841         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
 842                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 843                                     zone, net))
 844                         goto out;
 845
 846         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
 847                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 848                                     zone, net))
 849                         goto out;
 850
 851         smp_wmb();
 852         /* The caller holds a reference to this object */
 853         atomic_set(&ct->ct_general.use, 2);
 854         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 855         nf_conntrack_double_unlock(hash, reply_hash);
 856         NF_CT_STAT_INC(net, insert);
 857         local_bh_enable();
 858         return 0;
 859
 860 out:
 861         nf_conntrack_double_unlock(hash, reply_hash);
 862         NF_CT_STAT_INC(net, insert_failed);
 863         local_bh_enable();
 864         return -EEXIST;
 865 }
 866 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 867
 868 void nf_ct_acct_add(struct nf_conn *ct, u32 dir, unsigned int packets,
 869                     unsigned int bytes)
 870 {
 871         struct nf_conn_acct *acct;
 872
 873         acct = nf_conn_acct_find(ct);
 874         if (acct) {
 875                 struct nf_conn_counter *counter = acct->counter;
 876
 877                 atomic64_add(packets, &counter[dir].packets);
 878                 atomic64_add(bytes, &counter[dir].bytes);
 879         }
 880 }
 881 EXPORT_SYMBOL_GPL(nf_ct_acct_add);
 882
 883 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 884                              const struct nf_conn *loser_ct)
 885 {
 886         struct nf_conn_acct *acct;
 887
 888         acct = nf_conn_acct_find(loser_ct);
 889         if (acct) {
 890                 struct nf_conn_counter *counter = acct->counter;
 891                 unsigned int bytes;
 892
 893                 /* u32 should be fine since we must have seen one packet. */
 894                 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
 895                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), bytes);
 896         }
 897 }
 898
 899 static void __nf_conntrack_insert_prepare(struct nf_conn *ct)
 900 {
 901         struct nf_conn_tstamp *tstamp;
 902
 903         atomic_inc(&ct->ct_general.use);
 904         ct->status |= IPS_CONFIRMED;
 905
 906         /* set conntrack timestamp, if enabled. */
 907         tstamp = nf_conn_tstamp_find(ct);
 908         if (tstamp)
 909                 tstamp->start = ktime_get_real_ns();
 910 }
 911
 912 static int __nf_ct_resolve_clash(struct sk_buff *skb,
 913                                  struct nf_conntrack_tuple_hash *h)
 914 {
 915         /* This is the conntrack entry already in hashes that won race. */
 916         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 917         enum ip_conntrack_info ctinfo;
 918         struct nf_conn *loser_ct;
 919
 920         loser_ct = nf_ct_get(skb, &ctinfo);
 921
 922         if (nf_ct_is_dying(ct))
 923                 return NF_DROP;
 924
 925         if (!atomic_inc_not_zero(&ct->ct_general.use))
 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_ct_acct_merge(ct, ctinfo, loser_ct);
 933                 nf_ct_add_to_dying_list(loser_ct);
 934                 nf_conntrack_put(&loser_ct->ct_general);
 935                 nf_ct_set(skb, ct, ctinfo);
 936
 937                 NF_CT_STAT_INC(net, insert_failed);
 938                 return NF_ACCEPT;
 939         }
 940
 941         nf_ct_put(ct);
 942         return NF_DROP;
 943 }
 944
 945 /**
 946  * nf_ct_resolve_clash_harder - attempt to insert clashing conntrack entry
 947  *
 948  * @skb: skb that causes the collision
 949  * @repl_idx: hash slot for reply direction
 950  *
 951  * Called when origin or reply direction had a clash.
 952  * The skb can be handled without packet drop provided the reply direction
 953  * is unique or there the existing entry has the identical tuple in both
 954  * directions.
 955  *
 956  * Caller must hold conntrack table locks to prevent concurrent updates.
 957  *
 958  * Returns NF_DROP if the clash could not be handled.
 959  */
 960 static int nf_ct_resolve_clash_harder(struct sk_buff *skb, u32 repl_idx)
 961 {
 962         struct nf_conn *loser_ct = (struct nf_conn *)skb_nfct(skb);
 963         const struct nf_conntrack_zone *zone;
 964         struct nf_conntrack_tuple_hash *h;
 965         struct hlist_nulls_node *n;
 966         struct net *net;
 967
 968         zone = nf_ct_zone(loser_ct);
 969         net = nf_ct_net(loser_ct);
 970
 971         /* Reply direction must never result in a clash, unless both origin
 972          * and reply tuples are identical.
 973          */
 974         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[repl_idx], hnnode) {
 975                 if (nf_ct_key_equal(h,
 976                                     &loser_ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 977                                     zone, net))
 978                         return __nf_ct_resolve_clash(skb, h);
 979         }
 980
 981         /* We want the clashing entry to go away real soon: 1 second timeout. */
 982         loser_ct->timeout = nfct_time_stamp + HZ;
 983
 984         /* IPS_NAT_CLASH removes the entry automatically on the first
 985          * reply.  Also prevents UDP tracker from moving the entry to
 986          * ASSURED state, i.e. the entry can always be evicted under
 987          * pressure.
 988          */
 989         loser_ct->status |= IPS_FIXED_TIMEOUT | IPS_NAT_CLASH;
 990
 991         __nf_conntrack_insert_prepare(loser_ct);
 992
 993         /* fake add for ORIGINAL dir: we want lookups to only find the entry
 994          * already in the table.  This also hides the clashing entry from
 995          * ctnetlink iteration, i.e. conntrack -L won't show them.
 996          */
 997         hlist_nulls_add_fake(&loser_ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 998
 999         hlist_nulls_add_head_rcu(&loser_ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
1000                                  &nf_conntrack_hash[repl_idx]);
1001         return NF_ACCEPT;
1002 }
1003
1004 /**
1005  * nf_ct_resolve_clash - attempt to handle clash without packet drop
1006  *
1007  * @skb: skb that causes the clash
1008  * @h: tuplehash of the clashing entry already in table
1009  * @hash_reply: hash slot for reply direction
1010  *
1011  * A conntrack entry can be inserted to the connection tracking table
1012  * if there is no existing entry with an identical tuple.
1013  *
1014  * If there is one, @skb (and the assocated, unconfirmed conntrack) has
1015  * to be dropped.  In case @skb is retransmitted, next conntrack lookup
1016  * will find the already-existing entry.
1017  *
1018  * The major problem with such packet drop is the extra delay added by
1019  * the packet loss -- it will take some time for a retransmit to occur
1020  * (or the sender to time out when waiting for a reply).
1021  *
1022  * This function attempts to handle the situation without packet drop.
1023  *
1024  * If @skb has no NAT transformation or if the colliding entries are
1025  * exactly the same, only the to-be-confirmed conntrack entry is discarded
1026  * and @skb is associated with the conntrack entry already in the table.
1027  *
1028  * Failing that, the new, unconfirmed conntrack is still added to the table
1029  * provided that the collision only occurs in the ORIGINAL direction.
1030  * The new entry will be added after the existing one in the hash list,
1031  * so packets in the ORIGINAL direction will continue to match the existing
1032  * entry.  The new entry will also have a fixed timeout so it expires --
1033  * due to the collision, it will not see bidirectional traffic.
1034  *
1035  * Returns NF_DROP if the clash could not be resolved.
1036  */
1037 static __cold noinline int
1038 nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h,
1039                     u32 reply_hash)
1040 {
1041         /* This is the conntrack entry already in hashes that won race. */
1042         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
1043         const struct nf_conntrack_l4proto *l4proto;
1044         enum ip_conntrack_info ctinfo;
1045         struct nf_conn *loser_ct;
1046         struct net *net;
1047         int ret;
1048
1049         loser_ct = nf_ct_get(skb, &ctinfo);
1050         net = nf_ct_net(loser_ct);
1051
1052         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1053         if (!l4proto->allow_clash)
1054                 goto drop;
1055
1056         ret = __nf_ct_resolve_clash(skb, h);
1057         if (ret == NF_ACCEPT)
1058                 return ret;
1059
1060         ret = nf_ct_resolve_clash_harder(skb, reply_hash);
1061         if (ret == NF_ACCEPT)
1062                 return ret;
1063
1064 drop:
1065         nf_ct_add_to_dying_list(loser_ct);
1066         NF_CT_STAT_INC(net, drop);
1067         NF_CT_STAT_INC(net, insert_failed);
1068         return NF_DROP;
1069 }
1070
1071 /* Confirm a connection given skb; places it in hash table */
1072 int
1073 __nf_conntrack_confirm(struct sk_buff *skb)
1074 {
1075         const struct nf_conntrack_zone *zone;
1076         unsigned int hash, reply_hash;
1077         struct nf_conntrack_tuple_hash *h;
1078         struct nf_conn *ct;
1079         struct nf_conn_help *help;
1080         struct hlist_nulls_node *n;
1081         enum ip_conntrack_info ctinfo;
1082         struct net *net;
1083         unsigned int sequence;
1084         int ret = NF_DROP;
1085
1086         ct = nf_ct_get(skb, &ctinfo);
1087         net = nf_ct_net(ct);
1088
1089         /* ipt_REJECT uses nf_conntrack_attach to attach related
1090            ICMP/TCP RST packets in other direction.  Actual packet
1091            which created connection will be IP_CT_NEW or for an
1092            expected connection, IP_CT_RELATED. */
1093         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
1094                 return NF_ACCEPT;
1095
1096         zone = nf_ct_zone(ct);
1097         local_bh_disable();
1098
1099         do {
1100                 sequence = read_seqcount_begin(&nf_conntrack_generation);
1101                 /* reuse the hash saved before */
1102                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
1103                 hash = scale_hash(hash);
1104                 reply_hash = hash_conntrack(net,
1105                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
1106
1107         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
1108
1109         /* We're not in hash table, and we refuse to set up related
1110          * connections for unconfirmed conns.  But packet copies and
1111          * REJECT will give spurious warnings here.
1112          */
1113
1114         /* Another skb with the same unconfirmed conntrack may
1115          * win the race. This may happen for bridge(br_flood)
1116          * or broadcast/multicast packets do skb_clone with
1117          * unconfirmed conntrack.
1118          */
1119         if (unlikely(nf_ct_is_confirmed(ct))) {
1120                 WARN_ON_ONCE(1);
1121                 nf_conntrack_double_unlock(hash, reply_hash);
1122                 local_bh_enable();
1123                 return NF_DROP;
1124         }
1125
1126         pr_debug("Confirming conntrack %p\n", ct);
1127         /* We have to check the DYING flag after unlink to prevent
1128          * a race against nf_ct_get_next_corpse() possibly called from
1129          * user context, else we insert an already 'dead' hash, blocking
1130          * further use of that particular connection -JM.
1131          */
1132         nf_ct_del_from_dying_or_unconfirmed_list(ct);
1133
1134         if (unlikely(nf_ct_is_dying(ct))) {
1135                 nf_ct_add_to_dying_list(ct);
1136                 NF_CT_STAT_INC(net, insert_failed);
1137                 goto dying;
1138         }
1139
1140         /* See if there's one in the list already, including reverse:
1141            NAT could have grabbed it without realizing, since we're
1142            not in the hash.  If there is, we lost race. */
1143         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
1144                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1145                                     zone, net))
1146                         goto out;
1147
1148         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
1149                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1150                                     zone, net))
1151                         goto out;
1152
1153         /* Timer relative to confirmation time, not original
1154            setting time, otherwise we'd get timer wrap in
1155            weird delay cases. */
1156         ct->timeout += nfct_time_stamp;
1157
1158         __nf_conntrack_insert_prepare(ct);
1159
1160         /* Since the lookup is lockless, hash insertion must be done after
1161          * starting the timer and setting the CONFIRMED bit. The RCU barriers
1162          * guarantee that no other CPU can find the conntrack before the above
1163          * stores are visible.
1164          */
1165         __nf_conntrack_hash_insert(ct, hash, reply_hash);
1166         nf_conntrack_double_unlock(hash, reply_hash);
1167         local_bh_enable();
1168
1169         help = nfct_help(ct);
1170         if (help && help->helper)
1171                 nf_conntrack_event_cache(IPCT_HELPER, ct);
1172
1173         nf_conntrack_event_cache(master_ct(ct) ?
1174                                  IPCT_RELATED : IPCT_NEW, ct);
1175         return NF_ACCEPT;
1176
1177 out:
1178         ret = nf_ct_resolve_clash(skb, h, reply_hash);
1179 dying:
1180         nf_conntrack_double_unlock(hash, reply_hash);
1181         local_bh_enable();
1182         return ret;
1183 }
1184 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1185
1186 /* Returns true if a connection correspondings to the tuple (required
1187    for NAT). */
1188 int
1189 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1190                          const struct nf_conn *ignored_conntrack)
1191 {
1192         struct net *net = nf_ct_net(ignored_conntrack);
1193         const struct nf_conntrack_zone *zone;
1194         struct nf_conntrack_tuple_hash *h;
1195         struct hlist_nulls_head *ct_hash;
1196         unsigned int hash, hsize;
1197         struct hlist_nulls_node *n;
1198         struct nf_conn *ct;
1199
1200         zone = nf_ct_zone(ignored_conntrack);
1201
1202         rcu_read_lock();
1203  begin:
1204         nf_conntrack_get_ht(&ct_hash, &hsize);
1205         hash = __hash_conntrack(net, tuple, hsize);
1206
1207         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1208                 ct = nf_ct_tuplehash_to_ctrack(h);
1209
1210                 if (ct == ignored_conntrack)
1211                         continue;
1212
1213                 if (nf_ct_is_expired(ct)) {
1214                         nf_ct_gc_expired(ct);
1215                         continue;
1216                 }
1217
1218                 if (nf_ct_key_equal(h, tuple, zone, net)) {
1219                         /* Tuple is taken already, so caller will need to find
1220                          * a new source port to use.
1221                          *
1222                          * Only exception:
1223                          * If the *original tuples* are identical, then both
1224                          * conntracks refer to the same flow.
1225                          * This is a rare situation, it can occur e.g. when
1226                          * more than one UDP packet is sent from same socket
1227                          * in different threads.
1228                          *
1229                          * Let nf_ct_resolve_clash() deal with this later.
1230                          */
1231                         if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1232                                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple))
1233                                 continue;
1234
1235                         NF_CT_STAT_INC_ATOMIC(net, found);
1236                         rcu_read_unlock();
1237                         return 1;
1238                 }
1239         }
1240
1241         if (get_nulls_value(n) != hash) {
1242                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1243                 goto begin;
1244         }
1245
1246         rcu_read_unlock();
1247
1248         return 0;
1249 }
1250 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1251
1252 #define NF_CT_EVICTION_RANGE    8
1253
1254 /* There's a small race here where we may free a just-assured
1255    connection.  Too bad: we're in trouble anyway. */
1256 static unsigned int early_drop_list(struct net *net,
1257                                     struct hlist_nulls_head *head)
1258 {
1259         struct nf_conntrack_tuple_hash *h;
1260         struct hlist_nulls_node *n;
1261         unsigned int drops = 0;
1262         struct nf_conn *tmp;
1263
1264         hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1265                 tmp = nf_ct_tuplehash_to_ctrack(h);
1266
1267                 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1268                         continue;
1269
1270                 if (nf_ct_is_expired(tmp)) {
1271                         nf_ct_gc_expired(tmp);
1272                         continue;
1273                 }
1274
1275                 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1276                     !net_eq(nf_ct_net(tmp), net) ||
1277                     nf_ct_is_dying(tmp))
1278                         continue;
1279
1280                 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1281                         continue;
1282
1283                 /* kill only if still in same netns -- might have moved due to
1284                  * SLAB_TYPESAFE_BY_RCU rules.
1285                  *
1286                  * We steal the timer reference.  If that fails timer has
1287                  * already fired or someone else deleted it. Just drop ref
1288                  * and move to next entry.
1289                  */
1290                 if (net_eq(nf_ct_net(tmp), net) &&
1291                     nf_ct_is_confirmed(tmp) &&
1292                     nf_ct_delete(tmp, 0, 0))
1293                         drops++;
1294
1295                 nf_ct_put(tmp);
1296         }
1297
1298         return drops;
1299 }
1300
1301 static noinline int early_drop(struct net *net, unsigned int hash)
1302 {
1303         unsigned int i, bucket;
1304
1305         for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1306                 struct hlist_nulls_head *ct_hash;
1307                 unsigned int hsize, drops;
1308
1309                 rcu_read_lock();
1310                 nf_conntrack_get_ht(&ct_hash, &hsize);
1311                 if (!i)
1312                         bucket = reciprocal_scale(hash, hsize);
1313                 else
1314                         bucket = (bucket + 1) % hsize;
1315
1316                 drops = early_drop_list(net, &ct_hash[bucket]);
1317                 rcu_read_unlock();
1318
1319                 if (drops) {
1320                         NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1321                         return true;
1322                 }
1323         }
1324
1325         return false;
1326 }
1327
1328 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1329 {
1330         return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1331 }
1332
1333 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1334 {
1335         const struct nf_conntrack_l4proto *l4proto;
1336
1337         if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1338                 return true;
1339
1340         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1341         if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1342                 return true;
1343
1344         return false;
1345 }
1346
1347 #define DAY     (86400 * HZ)
1348
1349 /* Set an arbitrary timeout large enough not to ever expire, this save
1350  * us a check for the IPS_OFFLOAD_BIT from the packet path via
1351  * nf_ct_is_expired().
1352  */
1353 static void nf_ct_offload_timeout(struct nf_conn *ct)
1354 {
1355         if (nf_ct_expires(ct) < DAY / 2)
1356                 ct->timeout = nfct_time_stamp + DAY;
1357 }
1358
1359 static void gc_worker(struct work_struct *work)
1360 {
1361         unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
1362         unsigned int i, goal, buckets = 0, expired_count = 0;
1363         unsigned int nf_conntrack_max95 = 0;
1364         struct conntrack_gc_work *gc_work;
1365         unsigned int ratio, scanned = 0;
1366         unsigned long next_run;
1367
1368         gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1369
1370         goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
1371         i = gc_work->last_bucket;
1372         if (gc_work->early_drop)
1373                 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1374
1375         do {
1376                 struct nf_conntrack_tuple_hash *h;
1377                 struct hlist_nulls_head *ct_hash;
1378                 struct hlist_nulls_node *n;
1379                 unsigned int hashsz;
1380                 struct nf_conn *tmp;
1381
1382                 i++;
1383                 rcu_read_lock();
1384
1385                 nf_conntrack_get_ht(&ct_hash, &hashsz);
1386                 if (i >= hashsz)
1387                         i = 0;
1388
1389                 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1390                         struct net *net;
1391
1392                         tmp = nf_ct_tuplehash_to_ctrack(h);
1393
1394                         scanned++;
1395                         if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1396                                 nf_ct_offload_timeout(tmp);
1397                                 continue;
1398                         }
1399
1400                         if (nf_ct_is_expired(tmp)) {
1401                                 nf_ct_gc_expired(tmp);
1402                                 expired_count++;
1403                                 continue;
1404                         }
1405
1406                         if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1407                                 continue;
1408
1409                         net = nf_ct_net(tmp);
1410                         if (atomic_read(&net->ct.count) < nf_conntrack_max95)
1411                                 continue;
1412
1413                         /* need to take reference to avoid possible races */
1414                         if (!atomic_inc_not_zero(&tmp->ct_general.use))
1415                                 continue;
1416
1417                         if (gc_worker_skip_ct(tmp)) {
1418                                 nf_ct_put(tmp);
1419                                 continue;
1420                         }
1421
1422                         if (gc_worker_can_early_drop(tmp))
1423                                 nf_ct_kill(tmp);
1424
1425                         nf_ct_put(tmp);
1426                 }
1427
1428                 /* could check get_nulls_value() here and restart if ct
1429                  * was moved to another chain.  But given gc is best-effort
1430                  * we will just continue with next hash slot.
1431                  */
1432                 rcu_read_unlock();
1433                 cond_resched();
1434         } while (++buckets < goal);
1435
1436         if (gc_work->exiting)
1437                 return;
1438
1439         /*
1440          * Eviction will normally happen from the packet path, and not
1441          * from this gc worker.
1442          *
1443          * This worker is only here to reap expired entries when system went
1444          * idle after a busy period.
1445          *
1446          * The heuristics below are supposed to balance conflicting goals:
1447          *
1448          * 1. Minimize time until we notice a stale entry
1449          * 2. Maximize scan intervals to not waste cycles
1450          *
1451          * Normally, expire ratio will be close to 0.
1452          *
1453          * As soon as a sizeable fraction of the entries have expired
1454          * increase scan frequency.
1455          */
1456         ratio = scanned ? expired_count * 100 / scanned : 0;
1457         if (ratio > GC_EVICT_RATIO) {
1458                 gc_work->next_gc_run = min_interval;
1459         } else {
1460                 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1461
1462                 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1463
1464                 gc_work->next_gc_run += min_interval;
1465                 if (gc_work->next_gc_run > max)
1466                         gc_work->next_gc_run = max;
1467         }
1468
1469         next_run = gc_work->next_gc_run;
1470         gc_work->last_bucket = i;
1471         gc_work->early_drop = false;
1472         queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1473 }
1474
1475 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1476 {
1477         INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
1478         gc_work->next_gc_run = HZ;
1479         gc_work->exiting = false;
1480 }
1481
1482 static struct nf_conn *
1483 __nf_conntrack_alloc(struct net *net,
1484                      const struct nf_conntrack_zone *zone,
1485                      const struct nf_conntrack_tuple *orig,
1486                      const struct nf_conntrack_tuple *repl,
1487                      gfp_t gfp, u32 hash)
1488 {
1489         struct nf_conn *ct;
1490
1491         /* We don't want any race condition at early drop stage */
1492         atomic_inc(&net->ct.count);
1493
1494         if (nf_conntrack_max &&
1495             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
1496                 if (!early_drop(net, hash)) {
1497                         if (!conntrack_gc_work.early_drop)
1498                                 conntrack_gc_work.early_drop = true;
1499                         atomic_dec(&net->ct.count);
1500                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1501                         return ERR_PTR(-ENOMEM);
1502                 }
1503         }
1504
1505         /*
1506          * Do not use kmem_cache_zalloc(), as this cache uses
1507          * SLAB_TYPESAFE_BY_RCU.
1508          */
1509         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1510         if (ct == NULL)
1511                 goto out;
1512
1513         spin_lock_init(&ct->lock);
1514         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1515         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1516         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1517         /* save hash for reusing when confirming */
1518         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1519         ct->status = 0;
1520         ct->timeout = 0;
1521         write_pnet(&ct->ct_net, net);
1522         memset(&ct->__nfct_init_offset, 0,
1523                offsetof(struct nf_conn, proto) -
1524                offsetof(struct nf_conn, __nfct_init_offset));
1525
1526         nf_ct_zone_add(ct, zone);
1527
1528         /* Because we use RCU lookups, we set ct_general.use to zero before
1529          * this is inserted in any list.
1530          */
1531         atomic_set(&ct->ct_general.use, 0);
1532         return ct;
1533 out:
1534         atomic_dec(&net->ct.count);
1535         return ERR_PTR(-ENOMEM);
1536 }
1537
1538 struct nf_conn *nf_conntrack_alloc(struct net *net,
1539                                    const struct nf_conntrack_zone *zone,
1540                                    const struct nf_conntrack_tuple *orig,
1541                                    const struct nf_conntrack_tuple *repl,
1542                                    gfp_t gfp)
1543 {
1544         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1545 }
1546 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1547
1548 void nf_conntrack_free(struct nf_conn *ct)
1549 {
1550         struct net *net = nf_ct_net(ct);
1551
1552         /* A freed object has refcnt == 0, that's
1553          * the golden rule for SLAB_TYPESAFE_BY_RCU
1554          */
1555         WARN_ON(atomic_read(&ct->ct_general.use) != 0);
1556
1557         nf_ct_ext_destroy(ct);
1558         kmem_cache_free(nf_conntrack_cachep, ct);
1559         smp_mb__before_atomic();
1560         atomic_dec(&net->ct.count);
1561 }
1562 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1563
1564
1565 /* Allocate a new conntrack: we return -ENOMEM if classification
1566    failed due to stress.  Otherwise it really is unclassifiable. */
1567 static noinline struct nf_conntrack_tuple_hash *
1568 init_conntrack(struct net *net, struct nf_conn *tmpl,
1569                const struct nf_conntrack_tuple *tuple,
1570                struct sk_buff *skb,
1571                unsigned int dataoff, u32 hash)
1572 {
1573         struct nf_conn *ct;
1574         struct nf_conn_help *help;
1575         struct nf_conntrack_tuple repl_tuple;
1576         struct nf_conntrack_ecache *ecache;
1577         struct nf_conntrack_expect *exp = NULL;
1578         const struct nf_conntrack_zone *zone;
1579         struct nf_conn_timeout *timeout_ext;
1580         struct nf_conntrack_zone tmp;
1581
1582         if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1583                 pr_debug("Can't invert tuple.\n");
1584                 return NULL;
1585         }
1586
1587         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1588         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1589                                   hash);
1590         if (IS_ERR(ct))
1591                 return (struct nf_conntrack_tuple_hash *)ct;
1592
1593         if (!nf_ct_add_synproxy(ct, tmpl)) {
1594                 nf_conntrack_free(ct);
1595                 return ERR_PTR(-ENOMEM);
1596         }
1597
1598         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1599
1600         if (timeout_ext)
1601                 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1602                                       GFP_ATOMIC);
1603
1604         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1605         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1606         nf_ct_labels_ext_add(ct);
1607
1608         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1609         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1610                                  ecache ? ecache->expmask : 0,
1611                              GFP_ATOMIC);
1612
1613         local_bh_disable();
1614         if (net->ct.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                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1743         }
1744
1745         return ret;
1746 }
1747
1748 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1749                           enum ip_conntrack_info ctinfo)
1750 {
1751         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1752
1753         if (!timeout)
1754                 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1755
1756         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1757         return NF_ACCEPT;
1758 }
1759
1760 /* Returns verdict for packet, or -1 for invalid. */
1761 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1762                                       struct sk_buff *skb,
1763                                       unsigned int dataoff,
1764                                       enum ip_conntrack_info ctinfo,
1765                                       const struct nf_hook_state *state)
1766 {
1767         switch (nf_ct_protonum(ct)) {
1768         case IPPROTO_TCP:
1769                 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1770                                                ctinfo, state);
1771         case IPPROTO_UDP:
1772                 return nf_conntrack_udp_packet(ct, skb, dataoff,
1773                                                ctinfo, state);
1774         case IPPROTO_ICMP:
1775                 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1776 #if IS_ENABLED(CONFIG_IPV6)
1777         case IPPROTO_ICMPV6:
1778                 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1779 #endif
1780 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1781         case IPPROTO_UDPLITE:
1782                 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1783                                                    ctinfo, state);
1784 #endif
1785 #ifdef CONFIG_NF_CT_PROTO_SCTP
1786         case IPPROTO_SCTP:
1787                 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1788                                                 ctinfo, state);
1789 #endif
1790 #ifdef CONFIG_NF_CT_PROTO_DCCP
1791         case IPPROTO_DCCP:
1792                 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1793                                                 ctinfo, state);
1794 #endif
1795 #ifdef CONFIG_NF_CT_PROTO_GRE
1796         case IPPROTO_GRE:
1797                 return nf_conntrack_gre_packet(ct, skb, dataoff,
1798                                                ctinfo, state);
1799 #endif
1800         }
1801
1802         return generic_packet(ct, skb, ctinfo);
1803 }
1804
1805 unsigned int
1806 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1807 {
1808         enum ip_conntrack_info ctinfo;
1809         struct nf_conn *ct, *tmpl;
1810         u_int8_t protonum;
1811         int dataoff, ret;
1812
1813         tmpl = nf_ct_get(skb, &ctinfo);
1814         if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1815                 /* Previously seen (loopback or untracked)?  Ignore. */
1816                 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1817                      ctinfo == IP_CT_UNTRACKED) {
1818                         NF_CT_STAT_INC_ATOMIC(state->net, ignore);
1819                         return NF_ACCEPT;
1820                 }
1821                 skb->_nfct = 0;
1822         }
1823
1824         /* rcu_read_lock()ed by nf_hook_thresh */
1825         dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1826         if (dataoff <= 0) {
1827                 pr_debug("not prepared to track yet or error occurred\n");
1828                 NF_CT_STAT_INC_ATOMIC(state->net, error);
1829                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1830                 ret = NF_ACCEPT;
1831                 goto out;
1832         }
1833
1834         if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1835                 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1836                                                protonum, state);
1837                 if (ret <= 0) {
1838                         ret = -ret;
1839                         goto out;
1840                 }
1841                 /* ICMP[v6] protocol trackers may assign one conntrack. */
1842                 if (skb->_nfct)
1843                         goto out;
1844         }
1845 repeat:
1846         ret = resolve_normal_ct(tmpl, skb, dataoff,
1847                                 protonum, state);
1848         if (ret < 0) {
1849                 /* Too stressed to deal. */
1850                 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1851                 ret = NF_DROP;
1852                 goto out;
1853         }
1854
1855         ct = nf_ct_get(skb, &ctinfo);
1856         if (!ct) {
1857                 /* Not valid part of a connection */
1858                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1859                 ret = NF_ACCEPT;
1860                 goto out;
1861         }
1862
1863         ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
1864         if (ret <= 0) {
1865                 /* Invalid: inverse of the return code tells
1866                  * the netfilter core what to do */
1867                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1868                 nf_conntrack_put(&ct->ct_general);
1869                 skb->_nfct = 0;
1870                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1871                 if (ret == -NF_DROP)
1872                         NF_CT_STAT_INC_ATOMIC(state->net, drop);
1873                 /* Special case: TCP tracker reports an attempt to reopen a
1874                  * closed/aborted connection. We have to go back and create a
1875                  * fresh conntrack.
1876                  */
1877                 if (ret == -NF_REPEAT)
1878                         goto repeat;
1879                 ret = -ret;
1880                 goto out;
1881         }
1882
1883         if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
1884             !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1885                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1886 out:
1887         if (tmpl)
1888                 nf_ct_put(tmpl);
1889
1890         return ret;
1891 }
1892 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1893
1894 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1895    implicitly racy: see __nf_conntrack_confirm */
1896 void nf_conntrack_alter_reply(struct nf_conn *ct,
1897                               const struct nf_conntrack_tuple *newreply)
1898 {
1899         struct nf_conn_help *help = nfct_help(ct);
1900
1901         /* Should be unconfirmed, so not in hash table yet */
1902         WARN_ON(nf_ct_is_confirmed(ct));
1903
1904         pr_debug("Altering reply tuple of %p to ", ct);
1905         nf_ct_dump_tuple(newreply);
1906
1907         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1908         if (ct->master || (help && !hlist_empty(&help->expectations)))
1909                 return;
1910
1911         rcu_read_lock();
1912         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1913         rcu_read_unlock();
1914 }
1915 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1916
1917 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1918 void __nf_ct_refresh_acct(struct nf_conn *ct,
1919                           enum ip_conntrack_info ctinfo,
1920                           const struct sk_buff *skb,
1921                           u32 extra_jiffies,
1922                           bool do_acct)
1923 {
1924         /* Only update if this is not a fixed timeout */
1925         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1926                 goto acct;
1927
1928         /* If not in hash table, timer will not be active yet */
1929         if (nf_ct_is_confirmed(ct))
1930                 extra_jiffies += nfct_time_stamp;
1931
1932         if (READ_ONCE(ct->timeout) != extra_jiffies)
1933                 WRITE_ONCE(ct->timeout, extra_jiffies);
1934 acct:
1935         if (do_acct)
1936                 nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1937 }
1938 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1939
1940 bool nf_ct_kill_acct(struct nf_conn *ct,
1941                      enum ip_conntrack_info ctinfo,
1942                      const struct sk_buff *skb)
1943 {
1944         nf_ct_acct_update(ct, CTINFO2DIR(ctinfo), skb->len);
1945
1946         return nf_ct_delete(ct, 0, 0);
1947 }
1948 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1949
1950 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1951
1952 #include <linux/netfilter/nfnetlink.h>
1953 #include <linux/netfilter/nfnetlink_conntrack.h>
1954 #include <linux/mutex.h>
1955
1956 /* Generic function for tcp/udp/sctp/dccp and alike. */
1957 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1958                                const struct nf_conntrack_tuple *tuple)
1959 {
1960         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1961             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1962                 goto nla_put_failure;
1963         return 0;
1964
1965 nla_put_failure:
1966         return -1;
1967 }
1968 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1969
1970 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1971         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1972         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1973 };
1974 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1975
1976 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1977                                struct nf_conntrack_tuple *t,
1978                                u_int32_t flags)
1979 {
1980         if (flags & CTA_FILTER_FLAG(CTA_PROTO_SRC_PORT)) {
1981                 if (!tb[CTA_PROTO_SRC_PORT])
1982                         return -EINVAL;
1983
1984                 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1985         }
1986
1987         if (flags & CTA_FILTER_FLAG(CTA_PROTO_DST_PORT)) {
1988                 if (!tb[CTA_PROTO_DST_PORT])
1989                         return -EINVAL;
1990
1991                 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1992         }
1993
1994         return 0;
1995 }
1996 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1997
1998 unsigned int nf_ct_port_nlattr_tuple_size(void)
1999 {
2000         static unsigned int size __read_mostly;
2001
2002         if (!size)
2003                 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
2004
2005         return size;
2006 }
2007 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
2008 #endif
2009
2010 /* Used by ipt_REJECT and ip6t_REJECT. */
2011 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
2012 {
2013         struct nf_conn *ct;
2014         enum ip_conntrack_info ctinfo;
2015
2016         /* This ICMP is in reverse direction to the packet which caused it */
2017         ct = nf_ct_get(skb, &ctinfo);
2018         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
2019                 ctinfo = IP_CT_RELATED_REPLY;
2020         else
2021                 ctinfo = IP_CT_RELATED;
2022
2023         /* Attach to new skbuff, and increment count */
2024         nf_ct_set(nskb, ct, ctinfo);
2025         nf_conntrack_get(skb_nfct(nskb));
2026 }
2027
2028 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
2029                                  struct nf_conn *ct,
2030                                  enum ip_conntrack_info ctinfo)
2031 {
2032         struct nf_conntrack_tuple_hash *h;
2033         struct nf_conntrack_tuple tuple;
2034         struct nf_nat_hook *nat_hook;
2035         unsigned int status;
2036         int dataoff;
2037         u16 l3num;
2038         u8 l4num;
2039
2040         l3num = nf_ct_l3num(ct);
2041
2042         dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
2043         if (dataoff <= 0)
2044                 return -1;
2045
2046         if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
2047                              l4num, net, &tuple))
2048                 return -1;
2049
2050         if (ct->status & IPS_SRC_NAT) {
2051                 memcpy(tuple.src.u3.all,
2052                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
2053                        sizeof(tuple.src.u3.all));
2054                 tuple.src.u.all =
2055                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
2056         }
2057
2058         if (ct->status & IPS_DST_NAT) {
2059                 memcpy(tuple.dst.u3.all,
2060                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
2061                        sizeof(tuple.dst.u3.all));
2062                 tuple.dst.u.all =
2063                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
2064         }
2065
2066         h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
2067         if (!h)
2068                 return 0;
2069
2070         /* Store status bits of the conntrack that is clashing to re-do NAT
2071          * mangling according to what it has been done already to this packet.
2072          */
2073         status = ct->status;
2074
2075         nf_ct_put(ct);
2076         ct = nf_ct_tuplehash_to_ctrack(h);
2077         nf_ct_set(skb, ct, ctinfo);
2078
2079         nat_hook = rcu_dereference(nf_nat_hook);
2080         if (!nat_hook)
2081                 return 0;
2082
2083         if (status & IPS_SRC_NAT &&
2084             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
2085                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2086                 return -1;
2087
2088         if (status & IPS_DST_NAT &&
2089             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
2090                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
2091                 return -1;
2092
2093         return 0;
2094 }
2095
2096 /* This packet is coming from userspace via nf_queue, complete the packet
2097  * processing after the helper invocation in nf_confirm().
2098  */
2099 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
2100                                enum ip_conntrack_info ctinfo)
2101 {
2102         const struct nf_conntrack_helper *helper;
2103         const struct nf_conn_help *help;
2104         int protoff;
2105
2106         help = nfct_help(ct);
2107         if (!help)
2108                 return 0;
2109
2110         helper = rcu_dereference(help->helper);
2111         if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
2112                 return 0;
2113
2114         switch (nf_ct_l3num(ct)) {
2115         case NFPROTO_IPV4:
2116                 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
2117                 break;
2118 #if IS_ENABLED(CONFIG_IPV6)
2119         case NFPROTO_IPV6: {
2120                 __be16 frag_off;
2121                 u8 pnum;
2122
2123                 pnum = ipv6_hdr(skb)->nexthdr;
2124                 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
2125                                            &frag_off);
2126                 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
2127                         return 0;
2128                 break;
2129         }
2130 #endif
2131         default:
2132                 return 0;
2133         }
2134
2135         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
2136             !nf_is_loopback_packet(skb)) {
2137                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
2138                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
2139                         return -1;
2140                 }
2141         }
2142
2143         /* We've seen it coming out the other side: confirm it */
2144         return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
2145 }
2146
2147 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2148 {
2149         enum ip_conntrack_info ctinfo;
2150         struct nf_conn *ct;
2151         int err;
2152
2153         ct = nf_ct_get(skb, &ctinfo);
2154         if (!ct)
2155                 return 0;
2156
2157         if (!nf_ct_is_confirmed(ct)) {
2158                 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2159                 if (err < 0)
2160                         return err;
2161         }
2162
2163         return nf_confirm_cthelper(skb, ct, ctinfo);
2164 }
2165
2166 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2167                                        const struct sk_buff *skb)
2168 {
2169         const struct nf_conntrack_tuple *src_tuple;
2170         const struct nf_conntrack_tuple_hash *hash;
2171         struct nf_conntrack_tuple srctuple;
2172         enum ip_conntrack_info ctinfo;
2173         struct nf_conn *ct;
2174
2175         ct = nf_ct_get(skb, &ctinfo);
2176         if (ct) {
2177                 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2178                 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2179                 return true;
2180         }
2181
2182         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2183                                NFPROTO_IPV4, dev_net(skb->dev),
2184                                &srctuple))
2185                 return false;
2186
2187         hash = nf_conntrack_find_get(dev_net(skb->dev),
2188                                      &nf_ct_zone_dflt,
2189                                      &srctuple);
2190         if (!hash)
2191                 return false;
2192
2193         ct = nf_ct_tuplehash_to_ctrack(hash);
2194         src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2195         memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2196         nf_ct_put(ct);
2197
2198         return true;
2199 }
2200
2201 /* Bring out ya dead! */
2202 static struct nf_conn *
2203 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2204                 void *data, unsigned int *bucket)
2205 {
2206         struct nf_conntrack_tuple_hash *h;
2207         struct nf_conn *ct;
2208         struct hlist_nulls_node *n;
2209         spinlock_t *lockp;
2210
2211         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2212                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2213                 local_bh_disable();
2214                 nf_conntrack_lock(lockp);
2215                 if (*bucket < nf_conntrack_htable_size) {
2216                         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
2217                                 if (NF_CT_DIRECTION(h) != IP_CT_DIR_REPLY)
2218                                         continue;
2219                                 /* All nf_conn objects are added to hash table twice, one
2220                                  * for original direction tuple, once for the reply tuple.
2221                                  *
2222                                  * Exception: In the IPS_NAT_CLASH case, only the reply
2223                                  * tuple is added (the original tuple already existed for
2224                                  * a different object).
2225                                  *
2226                                  * We only need to call the iterator once for each
2227                                  * conntrack, so we just use the 'reply' direction
2228                                  * tuple while iterating.
2229                                  */
2230                                 ct = nf_ct_tuplehash_to_ctrack(h);
2231                                 if (iter(ct, data))
2232                                         goto found;
2233                         }
2234                 }
2235                 spin_unlock(lockp);
2236                 local_bh_enable();
2237                 cond_resched();
2238         }
2239
2240         return NULL;
2241 found:
2242         atomic_inc(&ct->ct_general.use);
2243         spin_unlock(lockp);
2244         local_bh_enable();
2245         return ct;
2246 }
2247
2248 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2249                                   void *data, u32 portid, int report)
2250 {
2251         unsigned int bucket = 0, sequence;
2252         struct nf_conn *ct;
2253
2254         might_sleep();
2255
2256         for (;;) {
2257                 sequence = read_seqcount_begin(&nf_conntrack_generation);
2258
2259                 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
2260                         /* Time to push up daises... */
2261
2262                         nf_ct_delete(ct, portid, report);
2263                         nf_ct_put(ct);
2264                         cond_resched();
2265                 }
2266
2267                 if (!read_seqcount_retry(&nf_conntrack_generation, sequence))
2268                         break;
2269                 bucket = 0;
2270         }
2271 }
2272
2273 struct iter_data {
2274         int (*iter)(struct nf_conn *i, void *data);
2275         void *data;
2276         struct net *net;
2277 };
2278
2279 static int iter_net_only(struct nf_conn *i, void *data)
2280 {
2281         struct iter_data *d = data;
2282
2283         if (!net_eq(d->net, nf_ct_net(i)))
2284                 return 0;
2285
2286         return d->iter(i, d->data);
2287 }
2288
2289 static void
2290 __nf_ct_unconfirmed_destroy(struct net *net)
2291 {
2292         int cpu;
2293
2294         for_each_possible_cpu(cpu) {
2295                 struct nf_conntrack_tuple_hash *h;
2296                 struct hlist_nulls_node *n;
2297                 struct ct_pcpu *pcpu;
2298
2299                 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2300
2301                 spin_lock_bh(&pcpu->lock);
2302                 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
2303                         struct nf_conn *ct;
2304
2305                         ct = nf_ct_tuplehash_to_ctrack(h);
2306
2307                         /* we cannot call iter() on unconfirmed list, the
2308                          * owning cpu can reallocate ct->ext at any time.
2309                          */
2310                         set_bit(IPS_DYING_BIT, &ct->status);
2311                 }
2312                 spin_unlock_bh(&pcpu->lock);
2313                 cond_resched();
2314         }
2315 }
2316
2317 void nf_ct_unconfirmed_destroy(struct net *net)
2318 {
2319         might_sleep();
2320
2321         if (atomic_read(&net->ct.count) > 0) {
2322                 __nf_ct_unconfirmed_destroy(net);
2323                 nf_queue_nf_hook_drop(net);
2324                 synchronize_net();
2325         }
2326 }
2327 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
2328
2329 void nf_ct_iterate_cleanup_net(struct net *net,
2330                                int (*iter)(struct nf_conn *i, void *data),
2331                                void *data, u32 portid, int report)
2332 {
2333         struct iter_data d;
2334
2335         might_sleep();
2336
2337         if (atomic_read(&net->ct.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                 if (atomic_read(&net->ct.count) == 0)
2367                         continue;
2368                 __nf_ct_unconfirmed_destroy(net);
2369                 nf_queue_nf_hook_drop(net);
2370         }
2371         up_read(&net_rwsem);
2372
2373         /* Need to wait for netns cleanup worker to finish, if its
2374          * running -- it might have deleted a net namespace from
2375          * the global list, so our __nf_ct_unconfirmed_destroy() might
2376          * not have affected all namespaces.
2377          */
2378         net_ns_barrier();
2379
2380         /* a conntrack could have been unlinked from unconfirmed list
2381          * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
2382          * This makes sure its inserted into conntrack table.
2383          */
2384         synchronize_net();
2385
2386         nf_ct_iterate_cleanup(iter, data, 0, 0);
2387 }
2388 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2389
2390 static int kill_all(struct nf_conn *i, void *data)
2391 {
2392         return net_eq(nf_ct_net(i), data);
2393 }
2394
2395 void nf_conntrack_cleanup_start(void)
2396 {
2397         conntrack_gc_work.exiting = true;
2398         RCU_INIT_POINTER(ip_ct_attach, NULL);
2399 }
2400
2401 void nf_conntrack_cleanup_end(void)
2402 {
2403         RCU_INIT_POINTER(nf_ct_hook, NULL);
2404         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2405         kvfree(nf_conntrack_hash);
2406
2407         nf_conntrack_proto_fini();
2408         nf_conntrack_seqadj_fini();
2409         nf_conntrack_labels_fini();
2410         nf_conntrack_helper_fini();
2411         nf_conntrack_timeout_fini();
2412         nf_conntrack_ecache_fini();
2413         nf_conntrack_tstamp_fini();
2414         nf_conntrack_acct_fini();
2415         nf_conntrack_expect_fini();
2416
2417         kmem_cache_destroy(nf_conntrack_cachep);
2418 }
2419
2420 /*
2421  * Mishearing the voices in his head, our hero wonders how he's
2422  * supposed to kill the mall.
2423  */
2424 void nf_conntrack_cleanup_net(struct net *net)
2425 {
2426         LIST_HEAD(single);
2427
2428         list_add(&net->exit_list, &single);
2429         nf_conntrack_cleanup_net_list(&single);
2430 }
2431
2432 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2433 {
2434         int busy;
2435         struct net *net;
2436
2437         /*
2438          * This makes sure all current packets have passed through
2439          *  netfilter framework.  Roll on, two-stage module
2440          *  delete...
2441          */
2442         synchronize_net();
2443 i_see_dead_people:
2444         busy = 0;
2445         list_for_each_entry(net, net_exit_list, exit_list) {
2446                 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
2447                 if (atomic_read(&net->ct.count) != 0)
2448                         busy = 1;
2449         }
2450         if (busy) {
2451                 schedule();
2452                 goto i_see_dead_people;
2453         }
2454
2455         list_for_each_entry(net, net_exit_list, exit_list) {
2456                 nf_conntrack_proto_pernet_fini(net);
2457                 nf_conntrack_ecache_pernet_fini(net);
2458                 nf_conntrack_expect_pernet_fini(net);
2459                 free_percpu(net->ct.stat);
2460                 free_percpu(net->ct.pcpu_lists);
2461         }
2462 }
2463
2464 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2465 {
2466         struct hlist_nulls_head *hash;
2467         unsigned int nr_slots, i;
2468
2469         if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2470                 return NULL;
2471
2472         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2473         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2474
2475         hash = kvcalloc(nr_slots, sizeof(struct hlist_nulls_head), GFP_KERNEL);
2476
2477         if (hash && nulls)
2478                 for (i = 0; i < nr_slots; i++)
2479                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
2480
2481         return hash;
2482 }
2483 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2484
2485 int nf_conntrack_hash_resize(unsigned int hashsize)
2486 {
2487         int i, bucket;
2488         unsigned int old_size;
2489         struct hlist_nulls_head *hash, *old_hash;
2490         struct nf_conntrack_tuple_hash *h;
2491         struct nf_conn *ct;
2492
2493         if (!hashsize)
2494                 return -EINVAL;
2495
2496         hash = nf_ct_alloc_hashtable(&hashsize, 1);
2497         if (!hash)
2498                 return -ENOMEM;
2499
2500         old_size = nf_conntrack_htable_size;
2501         if (old_size == hashsize) {
2502                 kvfree(hash);
2503                 return 0;
2504         }
2505
2506         local_bh_disable();
2507         nf_conntrack_all_lock();
2508         write_seqcount_begin(&nf_conntrack_generation);
2509
2510         /* Lookups in the old hash might happen in parallel, which means we
2511          * might get false negatives during connection lookup. New connections
2512          * created because of a false negative won't make it into the hash
2513          * though since that required taking the locks.
2514          */
2515
2516         for (i = 0; i < nf_conntrack_htable_size; i++) {
2517                 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2518                         h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2519                                               struct nf_conntrack_tuple_hash, hnnode);
2520                         ct = nf_ct_tuplehash_to_ctrack(h);
2521                         hlist_nulls_del_rcu(&h->hnnode);
2522                         bucket = __hash_conntrack(nf_ct_net(ct),
2523                                                   &h->tuple, hashsize);
2524                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2525                 }
2526         }
2527         old_size = nf_conntrack_htable_size;
2528         old_hash = nf_conntrack_hash;
2529
2530         nf_conntrack_hash = hash;
2531         nf_conntrack_htable_size = hashsize;
2532
2533         write_seqcount_end(&nf_conntrack_generation);
2534         nf_conntrack_all_unlock();
2535         local_bh_enable();
2536
2537         synchronize_net();
2538         kvfree(old_hash);
2539         return 0;
2540 }
2541
2542 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2543 {
2544         unsigned int hashsize;
2545         int rc;
2546
2547         if (current->nsproxy->net_ns != &init_net)
2548                 return -EOPNOTSUPP;
2549
2550         /* On boot, we can set this without any fancy locking. */
2551         if (!nf_conntrack_hash)
2552                 return param_set_uint(val, kp);
2553
2554         rc = kstrtouint(val, 0, &hashsize);
2555         if (rc)
2556                 return rc;
2557
2558         return nf_conntrack_hash_resize(hashsize);
2559 }
2560
2561 static __always_inline unsigned int total_extension_size(void)
2562 {
2563         /* remember to add new extensions below */
2564         BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
2565
2566         return sizeof(struct nf_ct_ext) +
2567                sizeof(struct nf_conn_help)
2568 #if IS_ENABLED(CONFIG_NF_NAT)
2569                 + sizeof(struct nf_conn_nat)
2570 #endif
2571                 + sizeof(struct nf_conn_seqadj)
2572                 + sizeof(struct nf_conn_acct)
2573 #ifdef CONFIG_NF_CONNTRACK_EVENTS
2574                 + sizeof(struct nf_conntrack_ecache)
2575 #endif
2576 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
2577                 + sizeof(struct nf_conn_tstamp)
2578 #endif
2579 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
2580                 + sizeof(struct nf_conn_timeout)
2581 #endif
2582 #ifdef CONFIG_NF_CONNTRACK_LABELS
2583                 + sizeof(struct nf_conn_labels)
2584 #endif
2585 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
2586                 + sizeof(struct nf_conn_synproxy)
2587 #endif
2588         ;
2589 };
2590
2591 int nf_conntrack_init_start(void)
2592 {
2593         unsigned long nr_pages = totalram_pages();
2594         int max_factor = 8;
2595         int ret = -ENOMEM;
2596         int i;
2597
2598         /* struct nf_ct_ext uses u8 to store offsets/size */
2599         BUILD_BUG_ON(total_extension_size() > 255u);
2600
2601         seqcount_init(&nf_conntrack_generation);
2602
2603         for (i = 0; i < CONNTRACK_LOCKS; i++)
2604                 spin_lock_init(&nf_conntrack_locks[i]);
2605
2606         if (!nf_conntrack_htable_size) {
2607                 /* Idea from tcp.c: use 1/16384 of memory.
2608                  * On i386: 32MB machine has 512 buckets.
2609                  * >= 1GB machines have 16384 buckets.
2610                  * >= 4GB machines have 65536 buckets.
2611                  */
2612                 nf_conntrack_htable_size
2613                         = (((nr_pages << PAGE_SHIFT) / 16384)
2614                            / sizeof(struct hlist_head));
2615                 if (nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2616                         nf_conntrack_htable_size = 65536;
2617                 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2618                         nf_conntrack_htable_size = 16384;
2619                 if (nf_conntrack_htable_size < 32)
2620                         nf_conntrack_htable_size = 32;
2621
2622                 /* Use a max. factor of four by default to get the same max as
2623                  * with the old struct list_heads. When a table size is given
2624                  * we use the old value of 8 to avoid reducing the max.
2625                  * entries. */
2626                 max_factor = 4;
2627         }
2628
2629         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2630         if (!nf_conntrack_hash)
2631                 return -ENOMEM;
2632
2633         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2634
2635         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2636                                                 sizeof(struct nf_conn),
2637                                                 NFCT_INFOMASK + 1,
2638                                                 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2639         if (!nf_conntrack_cachep)
2640                 goto err_cachep;
2641
2642         ret = nf_conntrack_expect_init();
2643         if (ret < 0)
2644                 goto err_expect;
2645
2646         ret = nf_conntrack_acct_init();
2647         if (ret < 0)
2648                 goto err_acct;
2649
2650         ret = nf_conntrack_tstamp_init();
2651         if (ret < 0)
2652                 goto err_tstamp;
2653
2654         ret = nf_conntrack_ecache_init();
2655         if (ret < 0)
2656                 goto err_ecache;
2657
2658         ret = nf_conntrack_timeout_init();
2659         if (ret < 0)
2660                 goto err_timeout;
2661
2662         ret = nf_conntrack_helper_init();
2663         if (ret < 0)
2664                 goto err_helper;
2665
2666         ret = nf_conntrack_labels_init();
2667         if (ret < 0)
2668                 goto err_labels;
2669
2670         ret = nf_conntrack_seqadj_init();
2671         if (ret < 0)
2672                 goto err_seqadj;
2673
2674         ret = nf_conntrack_proto_init();
2675         if (ret < 0)
2676                 goto err_proto;
2677
2678         conntrack_gc_work_init(&conntrack_gc_work);
2679         queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2680
2681         return 0;
2682
2683 err_proto:
2684         nf_conntrack_seqadj_fini();
2685 err_seqadj:
2686         nf_conntrack_labels_fini();
2687 err_labels:
2688         nf_conntrack_helper_fini();
2689 err_helper:
2690         nf_conntrack_timeout_fini();
2691 err_timeout:
2692         nf_conntrack_ecache_fini();
2693 err_ecache:
2694         nf_conntrack_tstamp_fini();
2695 err_tstamp:
2696         nf_conntrack_acct_fini();
2697 err_acct:
2698         nf_conntrack_expect_fini();
2699 err_expect:
2700         kmem_cache_destroy(nf_conntrack_cachep);
2701 err_cachep:
2702         kvfree(nf_conntrack_hash);
2703         return ret;
2704 }
2705
2706 static struct nf_ct_hook nf_conntrack_hook = {
2707         .update         = nf_conntrack_update,
2708         .destroy        = destroy_conntrack,
2709         .get_tuple_skb  = nf_conntrack_get_tuple_skb,
2710 };
2711
2712 void nf_conntrack_init_end(void)
2713 {
2714         /* For use by REJECT target */
2715         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2716         RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2717 }
2718
2719 /*
2720  * We need to use special "null" values, not used in hash table
2721  */
2722 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
2723 #define DYING_NULLS_VAL         ((1<<30)+1)
2724
2725 int nf_conntrack_init_net(struct net *net)
2726 {
2727         int ret = -ENOMEM;
2728         int cpu;
2729
2730         BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2731         BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2732         atomic_set(&net->ct.count, 0);
2733
2734         net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2735         if (!net->ct.pcpu_lists)
2736                 goto err_stat;
2737
2738         for_each_possible_cpu(cpu) {
2739                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2740
2741                 spin_lock_init(&pcpu->lock);
2742                 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2743                 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2744         }
2745
2746         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2747         if (!net->ct.stat)
2748                 goto err_pcpu_lists;
2749
2750         ret = nf_conntrack_expect_pernet_init(net);
2751         if (ret < 0)
2752                 goto err_expect;
2753
2754         nf_conntrack_acct_pernet_init(net);
2755         nf_conntrack_tstamp_pernet_init(net);
2756         nf_conntrack_ecache_pernet_init(net);
2757         nf_conntrack_helper_pernet_init(net);
2758         nf_conntrack_proto_pernet_init(net);
2759
2760         return 0;
2761
2762 err_expect:
2763         free_percpu(net->ct.stat);
2764 err_pcpu_lists:
2765         free_percpu(net->ct.pcpu_lists);
2766 err_stat:
2767         return ret;
2768 }