net/netfilter/nf_conntrack

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
nf_conntrack_lock
nf_conntrack_double_unlock
nf_conntrack_double_lock
nf_conntrack_all_lock
nf_conntrack_all_unlock
hash_conntrack_raw
scale_hash
__hash_conntrack
hash_conntrack
nf_ct_get_tuple_ports
nf_ct_get_tuple
ipv4_get_l4proto
ipv6_get_l4proto
get_l4proto
nf_ct_get_tuplepr
nf_ct_invert_tuple
nf_ct_get_id
clean_from_lists
nf_ct_add_to_dying_list
nf_ct_add_to_unconfirmed_list
nf_ct_del_from_dying_or_unconfirmed_list
nf_ct_tmpl_alloc
nf_ct_tmpl_free
destroy_gre_conntrack
destroy_conntrack
nf_ct_delete_from_lists
nf_ct_delete
nf_ct_key_equal
nf_ct_match
nf_ct_gc_expired
____nf_conntrack_find
__nf_conntrack_find_get
nf_conntrack_find_get
__nf_conntrack_hash_insert
nf_conntrack_hash_check_insert
nf_ct_acct_update
nf_ct_acct_merge
nf_ct_resolve_clash
__nf_conntrack_confirm
nf_conntrack_tuple_taken
early_drop_list
early_drop
gc_worker_skip_ct
gc_worker_can_early_drop
nf_ct_offload_timeout
gc_worker
conntrack_gc_work_init
__nf_conntrack_alloc
nf_conntrack_alloc
nf_conntrack_free
init_conntrack
resolve_normal_ct
nf_conntrack_handle_icmp
generic_packet
nf_conntrack_handle_packet
nf_conntrack_in
nf_conntrack_alter_reply
__nf_ct_refresh_acct
nf_ct_kill_acct
nf_ct_port_tuple_to_nlattr
nf_ct_port_nlattr_to_tuple
nf_ct_port_nlattr_tuple_size
nf_conntrack_attach
__nf_conntrack_update
nf_confirm_cthelper
nf_conntrack_update
nf_conntrack_get_tuple_skb
get_next_corpse
nf_ct_iterate_cleanup
iter_net_only
__nf_ct_unconfirmed_destroy
nf_ct_unconfirmed_destroy
nf_ct_iterate_cleanup_net
nf_ct_iterate_destroy
kill_all
nf_conntrack_cleanup_start
nf_conntrack_cleanup_end
nf_conntrack_cleanup_net
nf_conntrack_cleanup_net_list
nf_ct_alloc_hashtable
nf_conntrack_hash_resize
nf_conntrack_set_hashsize
total_extension_size
nf_conntrack_init_start
nf_conntrack_init_end
nf_conntrack_init_net
   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 {
 147         int i;
 148 
 149         spin_lock(&nf_conntrack_locks_all_lock);
 150 
 151         nf_conntrack_locks_all = true;
 152 
 153         for (i = 0; i < CONNTRACK_LOCKS; i++) {
 154                 spin_lock(&nf_conntrack_locks[i]);
 155 
 156                 /* This spin_unlock provides the "release" to ensure that
 157                  * nf_conntrack_locks_all==true is visible to everyone that
 158                  * acquired spin_lock(&nf_conntrack_locks[]).
 159                  */
 160                 spin_unlock(&nf_conntrack_locks[i]);
 161         }
 162 }
 163 
 164 static void nf_conntrack_all_unlock(void)
 165 {
 166         /* All prior stores must be complete before we clear
 167          * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
 168          * might observe the false value but not the entire
 169          * critical section.
 170          * It pairs with the smp_load_acquire() in nf_conntrack_lock()
 171          */
 172         smp_store_release(&nf_conntrack_locks_all, false);
 173         spin_unlock(&nf_conntrack_locks_all_lock);
 174 }
 175 
 176 unsigned int nf_conntrack_htable_size __read_mostly;
 177 EXPORT_SYMBOL_GPL(nf_conntrack_htable_size);
 178 
 179 unsigned int nf_conntrack_max __read_mostly;
 180 EXPORT_SYMBOL_GPL(nf_conntrack_max);
 181 seqcount_t nf_conntrack_generation __read_mostly;
 182 static unsigned int nf_conntrack_hash_rnd __read_mostly;
 183 
 184 static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple,
 185                               const struct net *net)
 186 {
 187         unsigned int n;
 188         u32 seed;
 189 
 190         get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
 191 
 192         /* The direction must be ignored, so we hash everything up to the
 193          * destination ports (which is a multiple of 4) and treat the last
 194          * three bytes manually.
 195          */
 196         seed = nf_conntrack_hash_rnd ^ net_hash_mix(net);
 197         n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32);
 198         return jhash2((u32 *)tuple, n, seed ^
 199                       (((__force __u16)tuple->dst.u.all << 16) |
 200                       tuple->dst.protonum));
 201 }
 202 
 203 static u32 scale_hash(u32 hash)
 204 {
 205         return reciprocal_scale(hash, nf_conntrack_htable_size);
 206 }
 207 
 208 static u32 __hash_conntrack(const struct net *net,
 209                             const struct nf_conntrack_tuple *tuple,
 210                             unsigned int size)
 211 {
 212         return reciprocal_scale(hash_conntrack_raw(tuple, net), size);
 213 }
 214 
 215 static u32 hash_conntrack(const struct net *net,
 216                           const struct nf_conntrack_tuple *tuple)
 217 {
 218         return scale_hash(hash_conntrack_raw(tuple, net));
 219 }
 220 
 221 static bool nf_ct_get_tuple_ports(const struct sk_buff *skb,
 222                                   unsigned int dataoff,
 223                                   struct nf_conntrack_tuple *tuple)
 224 {       struct {
 225                 __be16 sport;
 226                 __be16 dport;
 227         } _inet_hdr, *inet_hdr;
 228 
 229         /* Actually only need first 4 bytes to get ports. */
 230         inet_hdr = skb_header_pointer(skb, dataoff, sizeof(_inet_hdr), &_inet_hdr);
 231         if (!inet_hdr)
 232                 return false;
 233 
 234         tuple->src.u.udp.port = inet_hdr->sport;
 235         tuple->dst.u.udp.port = inet_hdr->dport;
 236         return true;
 237 }
 238 
 239 static bool
 240 nf_ct_get_tuple(const struct sk_buff *skb,
 241                 unsigned int nhoff,
 242                 unsigned int dataoff,
 243                 u_int16_t l3num,
 244                 u_int8_t protonum,
 245                 struct net *net,
 246                 struct nf_conntrack_tuple *tuple)
 247 {
 248         unsigned int size;
 249         const __be32 *ap;
 250         __be32 _addrs[8];
 251 
 252         memset(tuple, 0, sizeof(*tuple));
 253 
 254         tuple->src.l3num = l3num;
 255         switch (l3num) {
 256         case NFPROTO_IPV4:
 257                 nhoff += offsetof(struct iphdr, saddr);
 258                 size = 2 * sizeof(__be32);
 259                 break;
 260         case NFPROTO_IPV6:
 261                 nhoff += offsetof(struct ipv6hdr, saddr);
 262                 size = sizeof(_addrs);
 263                 break;
 264         default:
 265                 return true;
 266         }
 267 
 268         ap = skb_header_pointer(skb, nhoff, size, _addrs);
 269         if (!ap)
 270                 return false;
 271 
 272         switch (l3num) {
 273         case NFPROTO_IPV4:
 274                 tuple->src.u3.ip = ap[0];
 275                 tuple->dst.u3.ip = ap[1];
 276                 break;
 277         case NFPROTO_IPV6:
 278                 memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
 279                 memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
 280                 break;
 281         }
 282 
 283         tuple->dst.protonum = protonum;
 284         tuple->dst.dir = IP_CT_DIR_ORIGINAL;
 285 
 286         switch (protonum) {
 287 #if IS_ENABLED(CONFIG_IPV6)
 288         case IPPROTO_ICMPV6:
 289                 return icmpv6_pkt_to_tuple(skb, dataoff, net, tuple);
 290 #endif
 291         case IPPROTO_ICMP:
 292                 return icmp_pkt_to_tuple(skb, dataoff, net, tuple);
 293 #ifdef CONFIG_NF_CT_PROTO_GRE
 294         case IPPROTO_GRE:
 295                 return gre_pkt_to_tuple(skb, dataoff, net, tuple);
 296 #endif
 297         case IPPROTO_TCP:
 298         case IPPROTO_UDP: /* fallthrough */
 299                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 300 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
 301         case IPPROTO_UDPLITE:
 302                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 303 #endif
 304 #ifdef CONFIG_NF_CT_PROTO_SCTP
 305         case IPPROTO_SCTP:
 306                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 307 #endif
 308 #ifdef CONFIG_NF_CT_PROTO_DCCP
 309         case IPPROTO_DCCP:
 310                 return nf_ct_get_tuple_ports(skb, dataoff, tuple);
 311 #endif
 312         default:
 313                 break;
 314         }
 315 
 316         return true;
 317 }
 318 
 319 static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 320                             u_int8_t *protonum)
 321 {
 322         int dataoff = -1;
 323         const struct iphdr *iph;
 324         struct iphdr _iph;
 325 
 326         iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
 327         if (!iph)
 328                 return -1;
 329 
 330         /* Conntrack defragments packets, we might still see fragments
 331          * inside ICMP packets though.
 332          */
 333         if (iph->frag_off & htons(IP_OFFSET))
 334                 return -1;
 335 
 336         dataoff = nhoff + (iph->ihl << 2);
 337         *protonum = iph->protocol;
 338 
 339         /* Check bogus IP headers */
 340         if (dataoff > skb->len) {
 341                 pr_debug("bogus IPv4 packet: nhoff %u, ihl %u, skblen %u\n",
 342                          nhoff, iph->ihl << 2, skb->len);
 343                 return -1;
 344         }
 345         return dataoff;
 346 }
 347 
 348 #if IS_ENABLED(CONFIG_IPV6)
 349 static int ipv6_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
 350                             u8 *protonum)
 351 {
 352         int protoff = -1;
 353         unsigned int extoff = nhoff + sizeof(struct ipv6hdr);
 354         __be16 frag_off;
 355         u8 nexthdr;
 356 
 357         if (skb_copy_bits(skb, nhoff + offsetof(struct ipv6hdr, nexthdr),
 358                           &nexthdr, sizeof(nexthdr)) != 0) {
 359                 pr_debug("can't get nexthdr\n");
 360                 return -1;
 361         }
 362         protoff = ipv6_skip_exthdr(skb, extoff, &nexthdr, &frag_off);
 363         /*
 364          * (protoff == skb->len) means the packet has not data, just
 365          * IPv6 and possibly extensions headers, but it is tracked anyway
 366          */
 367         if (protoff < 0 || (frag_off & htons(~0x7)) != 0) {
 368                 pr_debug("can't find proto in pkt\n");
 369                 return -1;
 370         }
 371 
 372         *protonum = nexthdr;
 373         return protoff;
 374 }
 375 #endif
 376 
 377 static int get_l4proto(const struct sk_buff *skb,
 378                        unsigned int nhoff, u8 pf, u8 *l4num)
 379 {
 380         switch (pf) {
 381         case NFPROTO_IPV4:
 382                 return ipv4_get_l4proto(skb, nhoff, l4num);
 383 #if IS_ENABLED(CONFIG_IPV6)
 384         case NFPROTO_IPV6:
 385                 return ipv6_get_l4proto(skb, nhoff, l4num);
 386 #endif
 387         default:
 388                 *l4num = 0;
 389                 break;
 390         }
 391         return -1;
 392 }
 393 
 394 bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 395                        u_int16_t l3num,
 396                        struct net *net, struct nf_conntrack_tuple *tuple)
 397 {
 398         u8 protonum;
 399         int protoff;
 400 
 401         protoff = get_l4proto(skb, nhoff, l3num, &protonum);
 402         if (protoff <= 0)
 403                 return false;
 404 
 405         return nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, net, tuple);
 406 }
 407 EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr);
 408 
 409 bool
 410 nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
 411                    const struct nf_conntrack_tuple *orig)
 412 {
 413         memset(inverse, 0, sizeof(*inverse));
 414 
 415         inverse->src.l3num = orig->src.l3num;
 416 
 417         switch (orig->src.l3num) {
 418         case NFPROTO_IPV4:
 419                 inverse->src.u3.ip = orig->dst.u3.ip;
 420                 inverse->dst.u3.ip = orig->src.u3.ip;
 421                 break;
 422         case NFPROTO_IPV6:
 423                 inverse->src.u3.in6 = orig->dst.u3.in6;
 424                 inverse->dst.u3.in6 = orig->src.u3.in6;
 425                 break;
 426         default:
 427                 break;
 428         }
 429 
 430         inverse->dst.dir = !orig->dst.dir;
 431 
 432         inverse->dst.protonum = orig->dst.protonum;
 433 
 434         switch (orig->dst.protonum) {
 435         case IPPROTO_ICMP:
 436                 return nf_conntrack_invert_icmp_tuple(inverse, orig);
 437 #if IS_ENABLED(CONFIG_IPV6)
 438         case IPPROTO_ICMPV6:
 439                 return nf_conntrack_invert_icmpv6_tuple(inverse, orig);
 440 #endif
 441         }
 442 
 443         inverse->src.u.all = orig->dst.u.all;
 444         inverse->dst.u.all = orig->src.u.all;
 445         return true;
 446 }
 447 EXPORT_SYMBOL_GPL(nf_ct_invert_tuple);
 448 
 449 /* Generate a almost-unique pseudo-id for a given conntrack.
 450  *
 451  * intentionally doesn't re-use any of the seeds used for hash
 452  * table location, we assume id gets exposed to userspace.
 453  *
 454  * Following nf_conn items do not change throughout lifetime
 455  * of the nf_conn:
 456  *
 457  * 1. nf_conn address
 458  * 2. nf_conn->master address (normally NULL)
 459  * 3. the associated net namespace
 460  * 4. the original direction tuple
 461  */
 462 u32 nf_ct_get_id(const struct nf_conn *ct)
 463 {
 464         static __read_mostly siphash_key_t ct_id_seed;
 465         unsigned long a, b, c, d;
 466 
 467         net_get_random_once(&ct_id_seed, sizeof(ct_id_seed));
 468 
 469         a = (unsigned long)ct;
 470         b = (unsigned long)ct->master;
 471         c = (unsigned long)nf_ct_net(ct);
 472         d = (unsigned long)siphash(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 473                                    sizeof(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple),
 474                                    &ct_id_seed);
 475 #ifdef CONFIG_64BIT
 476         return siphash_4u64((u64)a, (u64)b, (u64)c, (u64)d, &ct_id_seed);
 477 #else
 478         return siphash_4u32((u32)a, (u32)b, (u32)c, (u32)d, &ct_id_seed);
 479 #endif
 480 }
 481 EXPORT_SYMBOL_GPL(nf_ct_get_id);
 482 
 483 static void
 484 clean_from_lists(struct nf_conn *ct)
 485 {
 486         pr_debug("clean_from_lists(%p)\n", ct);
 487         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 488         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode);
 489 
 490         /* Destroy all pending expectations */
 491         nf_ct_remove_expectations(ct);
 492 }
 493 
 494 /* must be called with local_bh_disable */
 495 static void nf_ct_add_to_dying_list(struct nf_conn *ct)
 496 {
 497         struct ct_pcpu *pcpu;
 498 
 499         /* add this conntrack to the (per cpu) dying list */
 500         ct->cpu = smp_processor_id();
 501         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 502 
 503         spin_lock(&pcpu->lock);
 504         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 505                              &pcpu->dying);
 506         spin_unlock(&pcpu->lock);
 507 }
 508 
 509 /* must be called with local_bh_disable */
 510 static void nf_ct_add_to_unconfirmed_list(struct nf_conn *ct)
 511 {
 512         struct ct_pcpu *pcpu;
 513 
 514         /* add this conntrack to the (per cpu) unconfirmed list */
 515         ct->cpu = smp_processor_id();
 516         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 517 
 518         spin_lock(&pcpu->lock);
 519         hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 520                              &pcpu->unconfirmed);
 521         spin_unlock(&pcpu->lock);
 522 }
 523 
 524 /* must be called with local_bh_disable */
 525 static void nf_ct_del_from_dying_or_unconfirmed_list(struct nf_conn *ct)
 526 {
 527         struct ct_pcpu *pcpu;
 528 
 529         /* We overload first tuple to link into unconfirmed or dying list.*/
 530         pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 531 
 532         spin_lock(&pcpu->lock);
 533         BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode));
 534         hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 535         spin_unlock(&pcpu->lock);
 536 }
 537 
 538 #define NFCT_ALIGN(len) (((len) + NFCT_INFOMASK) & ~NFCT_INFOMASK)
 539 
 540 /* Released via destroy_conntrack() */
 541 struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
 542                                  const struct nf_conntrack_zone *zone,
 543                                  gfp_t flags)
 544 {
 545         struct nf_conn *tmpl, *p;
 546 
 547         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK) {
 548                 tmpl = kzalloc(sizeof(*tmpl) + NFCT_INFOMASK, flags);
 549                 if (!tmpl)
 550                         return NULL;
 551 
 552                 p = tmpl;
 553                 tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 554                 if (tmpl != p) {
 555                         tmpl = (struct nf_conn *)NFCT_ALIGN((unsigned long)p);
 556                         tmpl->proto.tmpl_padto = (char *)tmpl - (char *)p;
 557                 }
 558         } else {
 559                 tmpl = kzalloc(sizeof(*tmpl), flags);
 560                 if (!tmpl)
 561                         return NULL;
 562         }
 563 
 564         tmpl->status = IPS_TEMPLATE;
 565         write_pnet(&tmpl->ct_net, net);
 566         nf_ct_zone_add(tmpl, zone);
 567         atomic_set(&tmpl->ct_general.use, 0);
 568 
 569         return tmpl;
 570 }
 571 EXPORT_SYMBOL_GPL(nf_ct_tmpl_alloc);
 572 
 573 void nf_ct_tmpl_free(struct nf_conn *tmpl)
 574 {
 575         nf_ct_ext_destroy(tmpl);
 576         nf_ct_ext_free(tmpl);
 577 
 578         if (ARCH_KMALLOC_MINALIGN <= NFCT_INFOMASK)
 579                 kfree((char *)tmpl - tmpl->proto.tmpl_padto);
 580         else
 581                 kfree(tmpl);
 582 }
 583 EXPORT_SYMBOL_GPL(nf_ct_tmpl_free);
 584 
 585 static void destroy_gre_conntrack(struct nf_conn *ct)
 586 {
 587 #ifdef CONFIG_NF_CT_PROTO_GRE
 588         struct nf_conn *master = ct->master;
 589 
 590         if (master)
 591                 nf_ct_gre_keymap_destroy(master);
 592 #endif
 593 }
 594 
 595 static void
 596 destroy_conntrack(struct nf_conntrack *nfct)
 597 {
 598         struct nf_conn *ct = (struct nf_conn *)nfct;
 599 
 600         pr_debug("destroy_conntrack(%p)\n", ct);
 601         WARN_ON(atomic_read(&nfct->use) != 0);
 602 
 603         if (unlikely(nf_ct_is_template(ct))) {
 604                 nf_ct_tmpl_free(ct);
 605                 return;
 606         }
 607 
 608         if (unlikely(nf_ct_protonum(ct) == IPPROTO_GRE))
 609                 destroy_gre_conntrack(ct);
 610 
 611         local_bh_disable();
 612         /* Expectations will have been removed in clean_from_lists,
 613          * except TFTP can create an expectation on the first packet,
 614          * before connection is in the list, so we need to clean here,
 615          * too.
 616          */
 617         nf_ct_remove_expectations(ct);
 618 
 619         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 620 
 621         local_bh_enable();
 622 
 623         if (ct->master)
 624                 nf_ct_put(ct->master);
 625 
 626         pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct);
 627         nf_conntrack_free(ct);
 628 }
 629 
 630 static void nf_ct_delete_from_lists(struct nf_conn *ct)
 631 {
 632         struct net *net = nf_ct_net(ct);
 633         unsigned int hash, reply_hash;
 634         unsigned int sequence;
 635 
 636         nf_ct_helper_destroy(ct);
 637 
 638         local_bh_disable();
 639         do {
 640                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 641                 hash = hash_conntrack(net,
 642                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 643                 reply_hash = hash_conntrack(net,
 644                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 645         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 646 
 647         clean_from_lists(ct);
 648         nf_conntrack_double_unlock(hash, reply_hash);
 649 
 650         nf_ct_add_to_dying_list(ct);
 651 
 652         local_bh_enable();
 653 }
 654 
 655 bool nf_ct_delete(struct nf_conn *ct, u32 portid, int report)
 656 {
 657         struct nf_conn_tstamp *tstamp;
 658 
 659         if (test_and_set_bit(IPS_DYING_BIT, &ct->status))
 660                 return false;
 661 
 662         tstamp = nf_conn_tstamp_find(ct);
 663         if (tstamp && tstamp->stop == 0)
 664                 tstamp->stop = ktime_get_real_ns();
 665 
 666         if (nf_conntrack_event_report(IPCT_DESTROY, ct,
 667                                     portid, report) < 0) {
 668                 /* destroy event was not delivered. nf_ct_put will
 669                  * be done by event cache worker on redelivery.
 670                  */
 671                 nf_ct_delete_from_lists(ct);
 672                 nf_conntrack_ecache_delayed_work(nf_ct_net(ct));
 673                 return false;
 674         }
 675 
 676         nf_conntrack_ecache_work(nf_ct_net(ct));
 677         nf_ct_delete_from_lists(ct);
 678         nf_ct_put(ct);
 679         return true;
 680 }
 681 EXPORT_SYMBOL_GPL(nf_ct_delete);
 682 
 683 static inline bool
 684 nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
 685                 const struct nf_conntrack_tuple *tuple,
 686                 const struct nf_conntrack_zone *zone,
 687                 const struct net *net)
 688 {
 689         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 690 
 691         /* A conntrack can be recreated with the equal tuple,
 692          * so we need to check that the conntrack is confirmed
 693          */
 694         return nf_ct_tuple_equal(tuple, &h->tuple) &&
 695                nf_ct_zone_equal(ct, zone, NF_CT_DIRECTION(h)) &&
 696                nf_ct_is_confirmed(ct) &&
 697                net_eq(net, nf_ct_net(ct));
 698 }
 699 
 700 static inline bool
 701 nf_ct_match(const struct nf_conn *ct1, const struct nf_conn *ct2)
 702 {
 703         return nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 704                                  &ct2->tuplehash[IP_CT_DIR_ORIGINAL].tuple) &&
 705                nf_ct_tuple_equal(&ct1->tuplehash[IP_CT_DIR_REPLY].tuple,
 706                                  &ct2->tuplehash[IP_CT_DIR_REPLY].tuple) &&
 707                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_ORIGINAL) &&
 708                nf_ct_zone_equal(ct1, nf_ct_zone(ct2), IP_CT_DIR_REPLY) &&
 709                net_eq(nf_ct_net(ct1), nf_ct_net(ct2));
 710 }
 711 
 712 /* caller must hold rcu readlock and none of the nf_conntrack_locks */
 713 static void nf_ct_gc_expired(struct nf_conn *ct)
 714 {
 715         if (!atomic_inc_not_zero(&ct->ct_general.use))
 716                 return;
 717 
 718         if (nf_ct_should_gc(ct))
 719                 nf_ct_kill(ct);
 720 
 721         nf_ct_put(ct);
 722 }
 723 
 724 /*
 725  * Warning :
 726  * - Caller must take a reference on returned object
 727  *   and recheck nf_ct_tuple_equal(tuple, &h->tuple)
 728  */
 729 static struct nf_conntrack_tuple_hash *
 730 ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
 731                       const struct nf_conntrack_tuple *tuple, u32 hash)
 732 {
 733         struct nf_conntrack_tuple_hash *h;
 734         struct hlist_nulls_head *ct_hash;
 735         struct hlist_nulls_node *n;
 736         unsigned int bucket, hsize;
 737 
 738 begin:
 739         nf_conntrack_get_ht(&ct_hash, &hsize);
 740         bucket = reciprocal_scale(hash, hsize);
 741 
 742         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
 743                 struct nf_conn *ct;
 744 
 745                 ct = nf_ct_tuplehash_to_ctrack(h);
 746                 if (nf_ct_is_expired(ct)) {
 747                         nf_ct_gc_expired(ct);
 748                         continue;
 749                 }
 750 
 751                 if (nf_ct_key_equal(h, tuple, zone, net))
 752                         return h;
 753         }
 754         /*
 755          * if the nulls value we got at the end of this lookup is
 756          * not the expected one, we must restart lookup.
 757          * We probably met an item that was moved to another chain.
 758          */
 759         if (get_nulls_value(n) != bucket) {
 760                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
 761                 goto begin;
 762         }
 763 
 764         return NULL;
 765 }
 766 
 767 /* Find a connection corresponding to a tuple. */
 768 static struct nf_conntrack_tuple_hash *
 769 __nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 770                         const struct nf_conntrack_tuple *tuple, u32 hash)
 771 {
 772         struct nf_conntrack_tuple_hash *h;
 773         struct nf_conn *ct;
 774 
 775         rcu_read_lock();
 776 
 777         h = ____nf_conntrack_find(net, zone, tuple, hash);
 778         if (h) {
 779                 /* We have a candidate that matches the tuple we're interested
 780                  * in, try to obtain a reference and re-check tuple
 781                  */
 782                 ct = nf_ct_tuplehash_to_ctrack(h);
 783                 if (likely(atomic_inc_not_zero(&ct->ct_general.use))) {
 784                         if (likely(nf_ct_key_equal(h, tuple, zone, net)))
 785                                 goto found;
 786 
 787                         /* TYPESAFE_BY_RCU recycled the candidate */
 788                         nf_ct_put(ct);
 789                 }
 790 
 791                 h = NULL;
 792         }
 793 found:
 794         rcu_read_unlock();
 795 
 796         return h;
 797 }
 798 
 799 struct nf_conntrack_tuple_hash *
 800 nf_conntrack_find_get(struct net *net, const struct nf_conntrack_zone *zone,
 801                       const struct nf_conntrack_tuple *tuple)
 802 {
 803         return __nf_conntrack_find_get(net, zone, tuple,
 804                                        hash_conntrack_raw(tuple, net));
 805 }
 806 EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
 807 
 808 static void __nf_conntrack_hash_insert(struct nf_conn *ct,
 809                                        unsigned int hash,
 810                                        unsigned int reply_hash)
 811 {
 812         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
 813                            &nf_conntrack_hash[hash]);
 814         hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
 815                            &nf_conntrack_hash[reply_hash]);
 816 }
 817 
 818 int
 819 nf_conntrack_hash_check_insert(struct nf_conn *ct)
 820 {
 821         const struct nf_conntrack_zone *zone;
 822         struct net *net = nf_ct_net(ct);
 823         unsigned int hash, reply_hash;
 824         struct nf_conntrack_tuple_hash *h;
 825         struct hlist_nulls_node *n;
 826         unsigned int sequence;
 827 
 828         zone = nf_ct_zone(ct);
 829 
 830         local_bh_disable();
 831         do {
 832                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 833                 hash = hash_conntrack(net,
 834                                       &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 835                 reply_hash = hash_conntrack(net,
 836                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 837         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 838 
 839         /* See if there's one in the list already, including reverse */
 840         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
 841                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 842                                     zone, net))
 843                         goto out;
 844 
 845         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
 846                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 847                                     zone, net))
 848                         goto out;
 849 
 850         smp_wmb();
 851         /* The caller holds a reference to this object */
 852         atomic_set(&ct->ct_general.use, 2);
 853         __nf_conntrack_hash_insert(ct, hash, reply_hash);
 854         nf_conntrack_double_unlock(hash, reply_hash);
 855         NF_CT_STAT_INC(net, insert);
 856         local_bh_enable();
 857         return 0;
 858 
 859 out:
 860         nf_conntrack_double_unlock(hash, reply_hash);
 861         NF_CT_STAT_INC(net, insert_failed);
 862         local_bh_enable();
 863         return -EEXIST;
 864 }
 865 EXPORT_SYMBOL_GPL(nf_conntrack_hash_check_insert);
 866 
 867 static inline void nf_ct_acct_update(struct nf_conn *ct,
 868                                      enum ip_conntrack_info ctinfo,
 869                                      unsigned int len)
 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_inc(&counter[CTINFO2DIR(ctinfo)].packets);
 878                 atomic64_add(len, &counter[CTINFO2DIR(ctinfo)].bytes);
 879         }
 880 }
 881 
 882 static void nf_ct_acct_merge(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 883                              const struct nf_conn *loser_ct)
 884 {
 885         struct nf_conn_acct *acct;
 886 
 887         acct = nf_conn_acct_find(loser_ct);
 888         if (acct) {
 889                 struct nf_conn_counter *counter = acct->counter;
 890                 unsigned int bytes;
 891 
 892                 /* u32 should be fine since we must have seen one packet. */
 893                 bytes = atomic64_read(&counter[CTINFO2DIR(ctinfo)].bytes);
 894                 nf_ct_acct_update(ct, ctinfo, bytes);
 895         }
 896 }
 897 
 898 /* Resolve race on insertion if this protocol allows this. */
 899 static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb,
 900                                enum ip_conntrack_info ctinfo,
 901                                struct nf_conntrack_tuple_hash *h)
 902 {
 903         /* This is the conntrack entry already in hashes that won race. */
 904         struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
 905         const struct nf_conntrack_l4proto *l4proto;
 906         enum ip_conntrack_info oldinfo;
 907         struct nf_conn *loser_ct = nf_ct_get(skb, &oldinfo);
 908 
 909         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
 910         if (l4proto->allow_clash &&
 911             !nf_ct_is_dying(ct) &&
 912             atomic_inc_not_zero(&ct->ct_general.use)) {
 913                 if (((ct->status & IPS_NAT_DONE_MASK) == 0) ||
 914                     nf_ct_match(ct, loser_ct)) {
 915                         nf_ct_acct_merge(ct, ctinfo, loser_ct);
 916                         nf_conntrack_put(&loser_ct->ct_general);
 917                         nf_ct_set(skb, ct, oldinfo);
 918                         return NF_ACCEPT;
 919                 }
 920                 nf_ct_put(ct);
 921         }
 922         NF_CT_STAT_INC(net, drop);
 923         return NF_DROP;
 924 }
 925 
 926 /* Confirm a connection given skb; places it in hash table */
 927 int
 928 __nf_conntrack_confirm(struct sk_buff *skb)
 929 {
 930         const struct nf_conntrack_zone *zone;
 931         unsigned int hash, reply_hash;
 932         struct nf_conntrack_tuple_hash *h;
 933         struct nf_conn *ct;
 934         struct nf_conn_help *help;
 935         struct nf_conn_tstamp *tstamp;
 936         struct hlist_nulls_node *n;
 937         enum ip_conntrack_info ctinfo;
 938         struct net *net;
 939         unsigned int sequence;
 940         int ret = NF_DROP;
 941 
 942         ct = nf_ct_get(skb, &ctinfo);
 943         net = nf_ct_net(ct);
 944 
 945         /* ipt_REJECT uses nf_conntrack_attach to attach related
 946            ICMP/TCP RST packets in other direction.  Actual packet
 947            which created connection will be IP_CT_NEW or for an
 948            expected connection, IP_CT_RELATED. */
 949         if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL)
 950                 return NF_ACCEPT;
 951 
 952         zone = nf_ct_zone(ct);
 953         local_bh_disable();
 954 
 955         do {
 956                 sequence = read_seqcount_begin(&nf_conntrack_generation);
 957                 /* reuse the hash saved before */
 958                 hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
 959                 hash = scale_hash(hash);
 960                 reply_hash = hash_conntrack(net,
 961                                            &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 962 
 963         } while (nf_conntrack_double_lock(net, hash, reply_hash, sequence));
 964 
 965         /* We're not in hash table, and we refuse to set up related
 966          * connections for unconfirmed conns.  But packet copies and
 967          * REJECT will give spurious warnings here.
 968          */
 969 
 970         /* Another skb with the same unconfirmed conntrack may
 971          * win the race. This may happen for bridge(br_flood)
 972          * or broadcast/multicast packets do skb_clone with
 973          * unconfirmed conntrack.
 974          */
 975         if (unlikely(nf_ct_is_confirmed(ct))) {
 976                 WARN_ON_ONCE(1);
 977                 nf_conntrack_double_unlock(hash, reply_hash);
 978                 local_bh_enable();
 979                 return NF_DROP;
 980         }
 981 
 982         pr_debug("Confirming conntrack %p\n", ct);
 983         /* We have to check the DYING flag after unlink to prevent
 984          * a race against nf_ct_get_next_corpse() possibly called from
 985          * user context, else we insert an already 'dead' hash, blocking
 986          * further use of that particular connection -JM.
 987          */
 988         nf_ct_del_from_dying_or_unconfirmed_list(ct);
 989 
 990         if (unlikely(nf_ct_is_dying(ct))) {
 991                 nf_ct_add_to_dying_list(ct);
 992                 goto dying;
 993         }
 994 
 995         /* See if there's one in the list already, including reverse:
 996            NAT could have grabbed it without realizing, since we're
 997            not in the hash.  If there is, we lost race. */
 998         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[hash], hnnode)
 999                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1000                                     zone, net))
1001                         goto out;
1002 
1003         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[reply_hash], hnnode)
1004                 if (nf_ct_key_equal(h, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
1005                                     zone, net))
1006                         goto out;
1007 
1008         /* Timer relative to confirmation time, not original
1009            setting time, otherwise we'd get timer wrap in
1010            weird delay cases. */
1011         ct->timeout += nfct_time_stamp;
1012         atomic_inc(&ct->ct_general.use);
1013         ct->status |= IPS_CONFIRMED;
1014 
1015         /* set conntrack timestamp, if enabled. */
1016         tstamp = nf_conn_tstamp_find(ct);
1017         if (tstamp)
1018                 tstamp->start = ktime_get_real_ns();
1019 
1020         /* Since the lookup is lockless, hash insertion must be done after
1021          * starting the timer and setting the CONFIRMED bit. The RCU barriers
1022          * guarantee that no other CPU can find the conntrack before the above
1023          * stores are visible.
1024          */
1025         __nf_conntrack_hash_insert(ct, hash, reply_hash);
1026         nf_conntrack_double_unlock(hash, reply_hash);
1027         local_bh_enable();
1028 
1029         help = nfct_help(ct);
1030         if (help && help->helper)
1031                 nf_conntrack_event_cache(IPCT_HELPER, ct);
1032 
1033         nf_conntrack_event_cache(master_ct(ct) ?
1034                                  IPCT_RELATED : IPCT_NEW, ct);
1035         return NF_ACCEPT;
1036 
1037 out:
1038         nf_ct_add_to_dying_list(ct);
1039         ret = nf_ct_resolve_clash(net, skb, ctinfo, h);
1040 dying:
1041         nf_conntrack_double_unlock(hash, reply_hash);
1042         NF_CT_STAT_INC(net, insert_failed);
1043         local_bh_enable();
1044         return ret;
1045 }
1046 EXPORT_SYMBOL_GPL(__nf_conntrack_confirm);
1047 
1048 /* Returns true if a connection correspondings to the tuple (required
1049    for NAT). */
1050 int
1051 nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
1052                          const struct nf_conn *ignored_conntrack)
1053 {
1054         struct net *net = nf_ct_net(ignored_conntrack);
1055         const struct nf_conntrack_zone *zone;
1056         struct nf_conntrack_tuple_hash *h;
1057         struct hlist_nulls_head *ct_hash;
1058         unsigned int hash, hsize;
1059         struct hlist_nulls_node *n;
1060         struct nf_conn *ct;
1061 
1062         zone = nf_ct_zone(ignored_conntrack);
1063 
1064         rcu_read_lock();
1065  begin:
1066         nf_conntrack_get_ht(&ct_hash, &hsize);
1067         hash = __hash_conntrack(net, tuple, hsize);
1068 
1069         hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
1070                 ct = nf_ct_tuplehash_to_ctrack(h);
1071 
1072                 if (ct == ignored_conntrack)
1073                         continue;
1074 
1075                 if (nf_ct_is_expired(ct)) {
1076                         nf_ct_gc_expired(ct);
1077                         continue;
1078                 }
1079 
1080                 if (nf_ct_key_equal(h, tuple, zone, net)) {
1081                         /* Tuple is taken already, so caller will need to find
1082                          * a new source port to use.
1083                          *
1084                          * Only exception:
1085                          * If the *original tuples* are identical, then both
1086                          * conntracks refer to the same flow.
1087                          * This is a rare situation, it can occur e.g. when
1088                          * more than one UDP packet is sent from same socket
1089                          * in different threads.
1090                          *
1091                          * Let nf_ct_resolve_clash() deal with this later.
1092                          */
1093                         if (nf_ct_tuple_equal(&ignored_conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
1094                                               &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple))
1095                                 continue;
1096 
1097                         NF_CT_STAT_INC_ATOMIC(net, found);
1098                         rcu_read_unlock();
1099                         return 1;
1100                 }
1101         }
1102 
1103         if (get_nulls_value(n) != hash) {
1104                 NF_CT_STAT_INC_ATOMIC(net, search_restart);
1105                 goto begin;
1106         }
1107 
1108         rcu_read_unlock();
1109 
1110         return 0;
1111 }
1112 EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken);
1113 
1114 #define NF_CT_EVICTION_RANGE    8
1115 
1116 /* There's a small race here where we may free a just-assured
1117    connection.  Too bad: we're in trouble anyway. */
1118 static unsigned int early_drop_list(struct net *net,
1119                                     struct hlist_nulls_head *head)
1120 {
1121         struct nf_conntrack_tuple_hash *h;
1122         struct hlist_nulls_node *n;
1123         unsigned int drops = 0;
1124         struct nf_conn *tmp;
1125 
1126         hlist_nulls_for_each_entry_rcu(h, n, head, hnnode) {
1127                 tmp = nf_ct_tuplehash_to_ctrack(h);
1128 
1129                 if (test_bit(IPS_OFFLOAD_BIT, &tmp->status))
1130                         continue;
1131 
1132                 if (nf_ct_is_expired(tmp)) {
1133                         nf_ct_gc_expired(tmp);
1134                         continue;
1135                 }
1136 
1137                 if (test_bit(IPS_ASSURED_BIT, &tmp->status) ||
1138                     !net_eq(nf_ct_net(tmp), net) ||
1139                     nf_ct_is_dying(tmp))
1140                         continue;
1141 
1142                 if (!atomic_inc_not_zero(&tmp->ct_general.use))
1143                         continue;
1144 
1145                 /* kill only if still in same netns -- might have moved due to
1146                  * SLAB_TYPESAFE_BY_RCU rules.
1147                  *
1148                  * We steal the timer reference.  If that fails timer has
1149                  * already fired or someone else deleted it. Just drop ref
1150                  * and move to next entry.
1151                  */
1152                 if (net_eq(nf_ct_net(tmp), net) &&
1153                     nf_ct_is_confirmed(tmp) &&
1154                     nf_ct_delete(tmp, 0, 0))
1155                         drops++;
1156 
1157                 nf_ct_put(tmp);
1158         }
1159 
1160         return drops;
1161 }
1162 
1163 static noinline int early_drop(struct net *net, unsigned int hash)
1164 {
1165         unsigned int i, bucket;
1166 
1167         for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
1168                 struct hlist_nulls_head *ct_hash;
1169                 unsigned int hsize, drops;
1170 
1171                 rcu_read_lock();
1172                 nf_conntrack_get_ht(&ct_hash, &hsize);
1173                 if (!i)
1174                         bucket = reciprocal_scale(hash, hsize);
1175                 else
1176                         bucket = (bucket + 1) % hsize;
1177 
1178                 drops = early_drop_list(net, &ct_hash[bucket]);
1179                 rcu_read_unlock();
1180 
1181                 if (drops) {
1182                         NF_CT_STAT_ADD_ATOMIC(net, early_drop, drops);
1183                         return true;
1184                 }
1185         }
1186 
1187         return false;
1188 }
1189 
1190 static bool gc_worker_skip_ct(const struct nf_conn *ct)
1191 {
1192         return !nf_ct_is_confirmed(ct) || nf_ct_is_dying(ct);
1193 }
1194 
1195 static bool gc_worker_can_early_drop(const struct nf_conn *ct)
1196 {
1197         const struct nf_conntrack_l4proto *l4proto;
1198 
1199         if (!test_bit(IPS_ASSURED_BIT, &ct->status))
1200                 return true;
1201 
1202         l4proto = nf_ct_l4proto_find(nf_ct_protonum(ct));
1203         if (l4proto->can_early_drop && l4proto->can_early_drop(ct))
1204                 return true;
1205 
1206         return false;
1207 }
1208 
1209 #define DAY     (86400 * HZ)
1210 
1211 /* Set an arbitrary timeout large enough not to ever expire, this save
1212  * us a check for the IPS_OFFLOAD_BIT from the packet path via
1213  * nf_ct_is_expired().
1214  */
1215 static void nf_ct_offload_timeout(struct nf_conn *ct)
1216 {
1217         if (nf_ct_expires(ct) < DAY / 2)
1218                 ct->timeout = nfct_time_stamp + DAY;
1219 }
1220 
1221 static void gc_worker(struct work_struct *work)
1222 {
1223         unsigned int min_interval = max(HZ / GC_MAX_BUCKETS_DIV, 1u);
1224         unsigned int i, goal, buckets = 0, expired_count = 0;
1225         unsigned int nf_conntrack_max95 = 0;
1226         struct conntrack_gc_work *gc_work;
1227         unsigned int ratio, scanned = 0;
1228         unsigned long next_run;
1229 
1230         gc_work = container_of(work, struct conntrack_gc_work, dwork.work);
1231 
1232         goal = nf_conntrack_htable_size / GC_MAX_BUCKETS_DIV;
1233         i = gc_work->last_bucket;
1234         if (gc_work->early_drop)
1235                 nf_conntrack_max95 = nf_conntrack_max / 100u * 95u;
1236 
1237         do {
1238                 struct nf_conntrack_tuple_hash *h;
1239                 struct hlist_nulls_head *ct_hash;
1240                 struct hlist_nulls_node *n;
1241                 unsigned int hashsz;
1242                 struct nf_conn *tmp;
1243 
1244                 i++;
1245                 rcu_read_lock();
1246 
1247                 nf_conntrack_get_ht(&ct_hash, &hashsz);
1248                 if (i >= hashsz)
1249                         i = 0;
1250 
1251                 hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[i], hnnode) {
1252                         struct net *net;
1253 
1254                         tmp = nf_ct_tuplehash_to_ctrack(h);
1255 
1256                         scanned++;
1257                         if (test_bit(IPS_OFFLOAD_BIT, &tmp->status)) {
1258                                 nf_ct_offload_timeout(tmp);
1259                                 continue;
1260                         }
1261 
1262                         if (nf_ct_is_expired(tmp)) {
1263                                 nf_ct_gc_expired(tmp);
1264                                 expired_count++;
1265                                 continue;
1266                         }
1267 
1268                         if (nf_conntrack_max95 == 0 || gc_worker_skip_ct(tmp))
1269                                 continue;
1270 
1271                         net = nf_ct_net(tmp);
1272                         if (atomic_read(&net->ct.count) < nf_conntrack_max95)
1273                                 continue;
1274 
1275                         /* need to take reference to avoid possible races */
1276                         if (!atomic_inc_not_zero(&tmp->ct_general.use))
1277                                 continue;
1278 
1279                         if (gc_worker_skip_ct(tmp)) {
1280                                 nf_ct_put(tmp);
1281                                 continue;
1282                         }
1283 
1284                         if (gc_worker_can_early_drop(tmp))
1285                                 nf_ct_kill(tmp);
1286 
1287                         nf_ct_put(tmp);
1288                 }
1289 
1290                 /* could check get_nulls_value() here and restart if ct
1291                  * was moved to another chain.  But given gc is best-effort
1292                  * we will just continue with next hash slot.
1293                  */
1294                 rcu_read_unlock();
1295                 cond_resched();
1296         } while (++buckets < goal);
1297 
1298         if (gc_work->exiting)
1299                 return;
1300 
1301         /*
1302          * Eviction will normally happen from the packet path, and not
1303          * from this gc worker.
1304          *
1305          * This worker is only here to reap expired entries when system went
1306          * idle after a busy period.
1307          *
1308          * The heuristics below are supposed to balance conflicting goals:
1309          *
1310          * 1. Minimize time until we notice a stale entry
1311          * 2. Maximize scan intervals to not waste cycles
1312          *
1313          * Normally, expire ratio will be close to 0.
1314          *
1315          * As soon as a sizeable fraction of the entries have expired
1316          * increase scan frequency.
1317          */
1318         ratio = scanned ? expired_count * 100 / scanned : 0;
1319         if (ratio > GC_EVICT_RATIO) {
1320                 gc_work->next_gc_run = min_interval;
1321         } else {
1322                 unsigned int max = GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV;
1323 
1324                 BUILD_BUG_ON((GC_MAX_SCAN_JIFFIES / GC_MAX_BUCKETS_DIV) == 0);
1325 
1326                 gc_work->next_gc_run += min_interval;
1327                 if (gc_work->next_gc_run > max)
1328                         gc_work->next_gc_run = max;
1329         }
1330 
1331         next_run = gc_work->next_gc_run;
1332         gc_work->last_bucket = i;
1333         gc_work->early_drop = false;
1334         queue_delayed_work(system_power_efficient_wq, &gc_work->dwork, next_run);
1335 }
1336 
1337 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
1338 {
1339         INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
1340         gc_work->next_gc_run = HZ;
1341         gc_work->exiting = false;
1342 }
1343 
1344 static struct nf_conn *
1345 __nf_conntrack_alloc(struct net *net,
1346                      const struct nf_conntrack_zone *zone,
1347                      const struct nf_conntrack_tuple *orig,
1348                      const struct nf_conntrack_tuple *repl,
1349                      gfp_t gfp, u32 hash)
1350 {
1351         struct nf_conn *ct;
1352 
1353         /* We don't want any race condition at early drop stage */
1354         atomic_inc(&net->ct.count);
1355 
1356         if (nf_conntrack_max &&
1357             unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) {
1358                 if (!early_drop(net, hash)) {
1359                         if (!conntrack_gc_work.early_drop)
1360                                 conntrack_gc_work.early_drop = true;
1361                         atomic_dec(&net->ct.count);
1362                         net_warn_ratelimited("nf_conntrack: table full, dropping packet\n");
1363                         return ERR_PTR(-ENOMEM);
1364                 }
1365         }
1366 
1367         /*
1368          * Do not use kmem_cache_zalloc(), as this cache uses
1369          * SLAB_TYPESAFE_BY_RCU.
1370          */
1371         ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
1372         if (ct == NULL)
1373                 goto out;
1374 
1375         spin_lock_init(&ct->lock);
1376         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
1377         ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
1378         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
1379         /* save hash for reusing when confirming */
1380         *(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
1381         ct->status = 0;
1382         ct->timeout = 0;
1383         write_pnet(&ct->ct_net, net);
1384         memset(&ct->__nfct_init_offset, 0,
1385                offsetof(struct nf_conn, proto) -
1386                offsetof(struct nf_conn, __nfct_init_offset));
1387 
1388         nf_ct_zone_add(ct, zone);
1389 
1390         /* Because we use RCU lookups, we set ct_general.use to zero before
1391          * this is inserted in any list.
1392          */
1393         atomic_set(&ct->ct_general.use, 0);
1394         return ct;
1395 out:
1396         atomic_dec(&net->ct.count);
1397         return ERR_PTR(-ENOMEM);
1398 }
1399 
1400 struct nf_conn *nf_conntrack_alloc(struct net *net,
1401                                    const struct nf_conntrack_zone *zone,
1402                                    const struct nf_conntrack_tuple *orig,
1403                                    const struct nf_conntrack_tuple *repl,
1404                                    gfp_t gfp)
1405 {
1406         return __nf_conntrack_alloc(net, zone, orig, repl, gfp, 0);
1407 }
1408 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
1409 
1410 void nf_conntrack_free(struct nf_conn *ct)
1411 {
1412         struct net *net = nf_ct_net(ct);
1413 
1414         /* A freed object has refcnt == 0, that's
1415          * the golden rule for SLAB_TYPESAFE_BY_RCU
1416          */
1417         WARN_ON(atomic_read(&ct->ct_general.use) != 0);
1418 
1419         nf_ct_ext_destroy(ct);
1420         nf_ct_ext_free(ct);
1421         kmem_cache_free(nf_conntrack_cachep, ct);
1422         smp_mb__before_atomic();
1423         atomic_dec(&net->ct.count);
1424 }
1425 EXPORT_SYMBOL_GPL(nf_conntrack_free);
1426 
1427 
1428 /* Allocate a new conntrack: we return -ENOMEM if classification
1429    failed due to stress.  Otherwise it really is unclassifiable. */
1430 static noinline struct nf_conntrack_tuple_hash *
1431 init_conntrack(struct net *net, struct nf_conn *tmpl,
1432                const struct nf_conntrack_tuple *tuple,
1433                struct sk_buff *skb,
1434                unsigned int dataoff, u32 hash)
1435 {
1436         struct nf_conn *ct;
1437         struct nf_conn_help *help;
1438         struct nf_conntrack_tuple repl_tuple;
1439         struct nf_conntrack_ecache *ecache;
1440         struct nf_conntrack_expect *exp = NULL;
1441         const struct nf_conntrack_zone *zone;
1442         struct nf_conn_timeout *timeout_ext;
1443         struct nf_conntrack_zone tmp;
1444 
1445         if (!nf_ct_invert_tuple(&repl_tuple, tuple)) {
1446                 pr_debug("Can't invert tuple.\n");
1447                 return NULL;
1448         }
1449 
1450         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1451         ct = __nf_conntrack_alloc(net, zone, tuple, &repl_tuple, GFP_ATOMIC,
1452                                   hash);
1453         if (IS_ERR(ct))
1454                 return (struct nf_conntrack_tuple_hash *)ct;
1455 
1456         if (!nf_ct_add_synproxy(ct, tmpl)) {
1457                 nf_conntrack_free(ct);
1458                 return ERR_PTR(-ENOMEM);
1459         }
1460 
1461         timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL;
1462 
1463         if (timeout_ext)
1464                 nf_ct_timeout_ext_add(ct, rcu_dereference(timeout_ext->timeout),
1465                                       GFP_ATOMIC);
1466 
1467         nf_ct_acct_ext_add(ct, GFP_ATOMIC);
1468         nf_ct_tstamp_ext_add(ct, GFP_ATOMIC);
1469         nf_ct_labels_ext_add(ct);
1470 
1471         ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL;
1472         nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0,
1473                                  ecache ? ecache->expmask : 0,
1474                              GFP_ATOMIC);
1475 
1476         local_bh_disable();
1477         if (net->ct.expect_count) {
1478                 spin_lock(&nf_conntrack_expect_lock);
1479                 exp = nf_ct_find_expectation(net, zone, tuple);
1480                 if (exp) {
1481                         pr_debug("expectation arrives ct=%p exp=%p\n",
1482                                  ct, exp);
1483                         /* Welcome, Mr. Bond.  We've been expecting you... */
1484                         __set_bit(IPS_EXPECTED_BIT, &ct->status);
1485                         /* exp->master safe, refcnt bumped in nf_ct_find_expectation */
1486                         ct->master = exp->master;
1487                         if (exp->helper) {
1488                                 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
1489                                 if (help)
1490                                         rcu_assign_pointer(help->helper, exp->helper);
1491                         }
1492 
1493 #ifdef CONFIG_NF_CONNTRACK_MARK
1494                         ct->mark = exp->master->mark;
1495 #endif
1496 #ifdef CONFIG_NF_CONNTRACK_SECMARK
1497                         ct->secmark = exp->master->secmark;
1498 #endif
1499                         NF_CT_STAT_INC(net, expect_new);
1500                 }
1501                 spin_unlock(&nf_conntrack_expect_lock);
1502         }
1503         if (!exp)
1504                 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC);
1505 
1506         /* Now it is inserted into the unconfirmed list, bump refcount */
1507         nf_conntrack_get(&ct->ct_general);
1508         nf_ct_add_to_unconfirmed_list(ct);
1509 
1510         local_bh_enable();
1511 
1512         if (exp) {
1513                 if (exp->expectfn)
1514                         exp->expectfn(ct, exp);
1515                 nf_ct_expect_put(exp);
1516         }
1517 
1518         return &ct->tuplehash[IP_CT_DIR_ORIGINAL];
1519 }
1520 
1521 /* On success, returns 0, sets skb->_nfct | ctinfo */
1522 static int
1523 resolve_normal_ct(struct nf_conn *tmpl,
1524                   struct sk_buff *skb,
1525                   unsigned int dataoff,
1526                   u_int8_t protonum,
1527                   const struct nf_hook_state *state)
1528 {
1529         const struct nf_conntrack_zone *zone;
1530         struct nf_conntrack_tuple tuple;
1531         struct nf_conntrack_tuple_hash *h;
1532         enum ip_conntrack_info ctinfo;
1533         struct nf_conntrack_zone tmp;
1534         struct nf_conn *ct;
1535         u32 hash;
1536 
1537         if (!nf_ct_get_tuple(skb, skb_network_offset(skb),
1538                              dataoff, state->pf, protonum, state->net,
1539                              &tuple)) {
1540                 pr_debug("Can't get tuple\n");
1541                 return 0;
1542         }
1543 
1544         /* look for tuple match */
1545         zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
1546         hash = hash_conntrack_raw(&tuple, state->net);
1547         h = __nf_conntrack_find_get(state->net, zone, &tuple, hash);
1548         if (!h) {
1549                 h = init_conntrack(state->net, tmpl, &tuple,
1550                                    skb, dataoff, hash);
1551                 if (!h)
1552                         return 0;
1553                 if (IS_ERR(h))
1554                         return PTR_ERR(h);
1555         }
1556         ct = nf_ct_tuplehash_to_ctrack(h);
1557 
1558         /* It exists; we have (non-exclusive) reference. */
1559         if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) {
1560                 ctinfo = IP_CT_ESTABLISHED_REPLY;
1561         } else {
1562                 /* Once we've had two way comms, always ESTABLISHED. */
1563                 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
1564                         pr_debug("normal packet for %p\n", ct);
1565                         ctinfo = IP_CT_ESTABLISHED;
1566                 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) {
1567                         pr_debug("related packet for %p\n", ct);
1568                         ctinfo = IP_CT_RELATED;
1569                 } else {
1570                         pr_debug("new packet for %p\n", ct);
1571                         ctinfo = IP_CT_NEW;
1572                 }
1573         }
1574         nf_ct_set(skb, ct, ctinfo);
1575         return 0;
1576 }
1577 
1578 /*
1579  * icmp packets need special treatment to handle error messages that are
1580  * related to a connection.
1581  *
1582  * Callers need to check if skb has a conntrack assigned when this
1583  * helper returns; in such case skb belongs to an already known connection.
1584  */
1585 static unsigned int __cold
1586 nf_conntrack_handle_icmp(struct nf_conn *tmpl,
1587                          struct sk_buff *skb,
1588                          unsigned int dataoff,
1589                          u8 protonum,
1590                          const struct nf_hook_state *state)
1591 {
1592         int ret;
1593 
1594         if (state->pf == NFPROTO_IPV4 && protonum == IPPROTO_ICMP)
1595                 ret = nf_conntrack_icmpv4_error(tmpl, skb, dataoff, state);
1596 #if IS_ENABLED(CONFIG_IPV6)
1597         else if (state->pf == NFPROTO_IPV6 && protonum == IPPROTO_ICMPV6)
1598                 ret = nf_conntrack_icmpv6_error(tmpl, skb, dataoff, state);
1599 #endif
1600         else
1601                 return NF_ACCEPT;
1602 
1603         if (ret <= 0) {
1604                 NF_CT_STAT_INC_ATOMIC(state->net, error);
1605                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1606         }
1607 
1608         return ret;
1609 }
1610 
1611 static int generic_packet(struct nf_conn *ct, struct sk_buff *skb,
1612                           enum ip_conntrack_info ctinfo)
1613 {
1614         const unsigned int *timeout = nf_ct_timeout_lookup(ct);
1615 
1616         if (!timeout)
1617                 timeout = &nf_generic_pernet(nf_ct_net(ct))->timeout;
1618 
1619         nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
1620         return NF_ACCEPT;
1621 }
1622 
1623 /* Returns verdict for packet, or -1 for invalid. */
1624 static int nf_conntrack_handle_packet(struct nf_conn *ct,
1625                                       struct sk_buff *skb,
1626                                       unsigned int dataoff,
1627                                       enum ip_conntrack_info ctinfo,
1628                                       const struct nf_hook_state *state)
1629 {
1630         switch (nf_ct_protonum(ct)) {
1631         case IPPROTO_TCP:
1632                 return nf_conntrack_tcp_packet(ct, skb, dataoff,
1633                                                ctinfo, state);
1634         case IPPROTO_UDP:
1635                 return nf_conntrack_udp_packet(ct, skb, dataoff,
1636                                                ctinfo, state);
1637         case IPPROTO_ICMP:
1638                 return nf_conntrack_icmp_packet(ct, skb, ctinfo, state);
1639 #if IS_ENABLED(CONFIG_IPV6)
1640         case IPPROTO_ICMPV6:
1641                 return nf_conntrack_icmpv6_packet(ct, skb, ctinfo, state);
1642 #endif
1643 #ifdef CONFIG_NF_CT_PROTO_UDPLITE
1644         case IPPROTO_UDPLITE:
1645                 return nf_conntrack_udplite_packet(ct, skb, dataoff,
1646                                                    ctinfo, state);
1647 #endif
1648 #ifdef CONFIG_NF_CT_PROTO_SCTP
1649         case IPPROTO_SCTP:
1650                 return nf_conntrack_sctp_packet(ct, skb, dataoff,
1651                                                 ctinfo, state);
1652 #endif
1653 #ifdef CONFIG_NF_CT_PROTO_DCCP
1654         case IPPROTO_DCCP:
1655                 return nf_conntrack_dccp_packet(ct, skb, dataoff,
1656                                                 ctinfo, state);
1657 #endif
1658 #ifdef CONFIG_NF_CT_PROTO_GRE
1659         case IPPROTO_GRE:
1660                 return nf_conntrack_gre_packet(ct, skb, dataoff,
1661                                                ctinfo, state);
1662 #endif
1663         }
1664 
1665         return generic_packet(ct, skb, ctinfo);
1666 }
1667 
1668 unsigned int
1669 nf_conntrack_in(struct sk_buff *skb, const struct nf_hook_state *state)
1670 {
1671         enum ip_conntrack_info ctinfo;
1672         struct nf_conn *ct, *tmpl;
1673         u_int8_t protonum;
1674         int dataoff, ret;
1675 
1676         tmpl = nf_ct_get(skb, &ctinfo);
1677         if (tmpl || ctinfo == IP_CT_UNTRACKED) {
1678                 /* Previously seen (loopback or untracked)?  Ignore. */
1679                 if ((tmpl && !nf_ct_is_template(tmpl)) ||
1680                      ctinfo == IP_CT_UNTRACKED) {
1681                         NF_CT_STAT_INC_ATOMIC(state->net, ignore);
1682                         return NF_ACCEPT;
1683                 }
1684                 skb->_nfct = 0;
1685         }
1686 
1687         /* rcu_read_lock()ed by nf_hook_thresh */
1688         dataoff = get_l4proto(skb, skb_network_offset(skb), state->pf, &protonum);
1689         if (dataoff <= 0) {
1690                 pr_debug("not prepared to track yet or error occurred\n");
1691                 NF_CT_STAT_INC_ATOMIC(state->net, error);
1692                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1693                 ret = NF_ACCEPT;
1694                 goto out;
1695         }
1696 
1697         if (protonum == IPPROTO_ICMP || protonum == IPPROTO_ICMPV6) {
1698                 ret = nf_conntrack_handle_icmp(tmpl, skb, dataoff,
1699                                                protonum, state);
1700                 if (ret <= 0) {
1701                         ret = -ret;
1702                         goto out;
1703                 }
1704                 /* ICMP[v6] protocol trackers may assign one conntrack. */
1705                 if (skb->_nfct)
1706                         goto out;
1707         }
1708 repeat:
1709         ret = resolve_normal_ct(tmpl, skb, dataoff,
1710                                 protonum, state);
1711         if (ret < 0) {
1712                 /* Too stressed to deal. */
1713                 NF_CT_STAT_INC_ATOMIC(state->net, drop);
1714                 ret = NF_DROP;
1715                 goto out;
1716         }
1717 
1718         ct = nf_ct_get(skb, &ctinfo);
1719         if (!ct) {
1720                 /* Not valid part of a connection */
1721                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1722                 ret = NF_ACCEPT;
1723                 goto out;
1724         }
1725 
1726         ret = nf_conntrack_handle_packet(ct, skb, dataoff, ctinfo, state);
1727         if (ret <= 0) {
1728                 /* Invalid: inverse of the return code tells
1729                  * the netfilter core what to do */
1730                 pr_debug("nf_conntrack_in: Can't track with proto module\n");
1731                 nf_conntrack_put(&ct->ct_general);
1732                 skb->_nfct = 0;
1733                 NF_CT_STAT_INC_ATOMIC(state->net, invalid);
1734                 if (ret == -NF_DROP)
1735                         NF_CT_STAT_INC_ATOMIC(state->net, drop);
1736                 /* Special case: TCP tracker reports an attempt to reopen a
1737                  * closed/aborted connection. We have to go back and create a
1738                  * fresh conntrack.
1739                  */
1740                 if (ret == -NF_REPEAT)
1741                         goto repeat;
1742                 ret = -ret;
1743                 goto out;
1744         }
1745 
1746         if (ctinfo == IP_CT_ESTABLISHED_REPLY &&
1747             !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status))
1748                 nf_conntrack_event_cache(IPCT_REPLY, ct);
1749 out:
1750         if (tmpl)
1751                 nf_ct_put(tmpl);
1752 
1753         return ret;
1754 }
1755 EXPORT_SYMBOL_GPL(nf_conntrack_in);
1756 
1757 /* Alter reply tuple (maybe alter helper).  This is for NAT, and is
1758    implicitly racy: see __nf_conntrack_confirm */
1759 void nf_conntrack_alter_reply(struct nf_conn *ct,
1760                               const struct nf_conntrack_tuple *newreply)
1761 {
1762         struct nf_conn_help *help = nfct_help(ct);
1763 
1764         /* Should be unconfirmed, so not in hash table yet */
1765         WARN_ON(nf_ct_is_confirmed(ct));
1766 
1767         pr_debug("Altering reply tuple of %p to ", ct);
1768         nf_ct_dump_tuple(newreply);
1769 
1770         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
1771         if (ct->master || (help && !hlist_empty(&help->expectations)))
1772                 return;
1773 
1774         rcu_read_lock();
1775         __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC);
1776         rcu_read_unlock();
1777 }
1778 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
1779 
1780 /* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */
1781 void __nf_ct_refresh_acct(struct nf_conn *ct,
1782                           enum ip_conntrack_info ctinfo,
1783                           const struct sk_buff *skb,
1784                           u32 extra_jiffies,
1785                           bool do_acct)
1786 {
1787         /* Only update if this is not a fixed timeout */
1788         if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
1789                 goto acct;
1790 
1791         /* If not in hash table, timer will not be active yet */
1792         if (nf_ct_is_confirmed(ct))
1793                 extra_jiffies += nfct_time_stamp;
1794 
1795         if (READ_ONCE(ct->timeout) != extra_jiffies)
1796                 WRITE_ONCE(ct->timeout, extra_jiffies);
1797 acct:
1798         if (do_acct)
1799                 nf_ct_acct_update(ct, ctinfo, skb->len);
1800 }
1801 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
1802 
1803 bool nf_ct_kill_acct(struct nf_conn *ct,
1804                      enum ip_conntrack_info ctinfo,
1805                      const struct sk_buff *skb)
1806 {
1807         nf_ct_acct_update(ct, ctinfo, skb->len);
1808 
1809         return nf_ct_delete(ct, 0, 0);
1810 }
1811 EXPORT_SYMBOL_GPL(nf_ct_kill_acct);
1812 
1813 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
1814 
1815 #include <linux/netfilter/nfnetlink.h>
1816 #include <linux/netfilter/nfnetlink_conntrack.h>
1817 #include <linux/mutex.h>
1818 
1819 /* Generic function for tcp/udp/sctp/dccp and alike. */
1820 int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
1821                                const struct nf_conntrack_tuple *tuple)
1822 {
1823         if (nla_put_be16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port) ||
1824             nla_put_be16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port))
1825                 goto nla_put_failure;
1826         return 0;
1827 
1828 nla_put_failure:
1829         return -1;
1830 }
1831 EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr);
1832 
1833 const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = {
1834         [CTA_PROTO_SRC_PORT]  = { .type = NLA_U16 },
1835         [CTA_PROTO_DST_PORT]  = { .type = NLA_U16 },
1836 };
1837 EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy);
1838 
1839 int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
1840                                struct nf_conntrack_tuple *t)
1841 {
1842         if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT])
1843                 return -EINVAL;
1844 
1845         t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]);
1846         t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]);
1847 
1848         return 0;
1849 }
1850 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
1851 
1852 unsigned int nf_ct_port_nlattr_tuple_size(void)
1853 {
1854         static unsigned int size __read_mostly;
1855 
1856         if (!size)
1857                 size = nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
1858 
1859         return size;
1860 }
1861 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
1862 #endif
1863 
1864 /* Used by ipt_REJECT and ip6t_REJECT. */
1865 static void nf_conntrack_attach(struct sk_buff *nskb, const struct sk_buff *skb)
1866 {
1867         struct nf_conn *ct;
1868         enum ip_conntrack_info ctinfo;
1869 
1870         /* This ICMP is in reverse direction to the packet which caused it */
1871         ct = nf_ct_get(skb, &ctinfo);
1872         if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL)
1873                 ctinfo = IP_CT_RELATED_REPLY;
1874         else
1875                 ctinfo = IP_CT_RELATED;
1876 
1877         /* Attach to new skbuff, and increment count */
1878         nf_ct_set(nskb, ct, ctinfo);
1879         nf_conntrack_get(skb_nfct(nskb));
1880 }
1881 
1882 static int __nf_conntrack_update(struct net *net, struct sk_buff *skb,
1883                                  struct nf_conn *ct,
1884                                  enum ip_conntrack_info ctinfo)
1885 {
1886         struct nf_conntrack_tuple_hash *h;
1887         struct nf_conntrack_tuple tuple;
1888         struct nf_nat_hook *nat_hook;
1889         unsigned int status;
1890         int dataoff;
1891         u16 l3num;
1892         u8 l4num;
1893 
1894         l3num = nf_ct_l3num(ct);
1895 
1896         dataoff = get_l4proto(skb, skb_network_offset(skb), l3num, &l4num);
1897         if (dataoff <= 0)
1898                 return -1;
1899 
1900         if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
1901                              l4num, net, &tuple))
1902                 return -1;
1903 
1904         if (ct->status & IPS_SRC_NAT) {
1905                 memcpy(tuple.src.u3.all,
1906                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.all,
1907                        sizeof(tuple.src.u3.all));
1908                 tuple.src.u.all =
1909                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.all;
1910         }
1911 
1912         if (ct->status & IPS_DST_NAT) {
1913                 memcpy(tuple.dst.u3.all,
1914                        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.all,
1915                        sizeof(tuple.dst.u3.all));
1916                 tuple.dst.u.all =
1917                         ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u.all;
1918         }
1919 
1920         h = nf_conntrack_find_get(net, nf_ct_zone(ct), &tuple);
1921         if (!h)
1922                 return 0;
1923 
1924         /* Store status bits of the conntrack that is clashing to re-do NAT
1925          * mangling according to what it has been done already to this packet.
1926          */
1927         status = ct->status;
1928 
1929         nf_ct_put(ct);
1930         ct = nf_ct_tuplehash_to_ctrack(h);
1931         nf_ct_set(skb, ct, ctinfo);
1932 
1933         nat_hook = rcu_dereference(nf_nat_hook);
1934         if (!nat_hook)
1935                 return 0;
1936 
1937         if (status & IPS_SRC_NAT &&
1938             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_SRC,
1939                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
1940                 return -1;
1941 
1942         if (status & IPS_DST_NAT &&
1943             nat_hook->manip_pkt(skb, ct, NF_NAT_MANIP_DST,
1944                                 IP_CT_DIR_ORIGINAL) == NF_DROP)
1945                 return -1;
1946 
1947         return 0;
1948 }
1949 
1950 /* This packet is coming from userspace via nf_queue, complete the packet
1951  * processing after the helper invocation in nf_confirm().
1952  */
1953 static int nf_confirm_cthelper(struct sk_buff *skb, struct nf_conn *ct,
1954                                enum ip_conntrack_info ctinfo)
1955 {
1956         const struct nf_conntrack_helper *helper;
1957         const struct nf_conn_help *help;
1958         int protoff;
1959 
1960         help = nfct_help(ct);
1961         if (!help)
1962                 return 0;
1963 
1964         helper = rcu_dereference(help->helper);
1965         if (!(helper->flags & NF_CT_HELPER_F_USERSPACE))
1966                 return 0;
1967 
1968         switch (nf_ct_l3num(ct)) {
1969         case NFPROTO_IPV4:
1970                 protoff = skb_network_offset(skb) + ip_hdrlen(skb);
1971                 break;
1972 #if IS_ENABLED(CONFIG_IPV6)
1973         case NFPROTO_IPV6: {
1974                 __be16 frag_off;
1975                 u8 pnum;
1976 
1977                 pnum = ipv6_hdr(skb)->nexthdr;
1978                 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &pnum,
1979                                            &frag_off);
1980                 if (protoff < 0 || (frag_off & htons(~0x7)) != 0)
1981                         return 0;
1982                 break;
1983         }
1984 #endif
1985         default:
1986                 return 0;
1987         }
1988 
1989         if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
1990             !nf_is_loopback_packet(skb)) {
1991                 if (!nf_ct_seq_adjust(skb, ct, ctinfo, protoff)) {
1992                         NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
1993                         return -1;
1994                 }
1995         }
1996 
1997         /* We've seen it coming out the other side: confirm it */
1998         return nf_conntrack_confirm(skb) == NF_DROP ? - 1 : 0;
1999 }
2000 
2001 static int nf_conntrack_update(struct net *net, struct sk_buff *skb)
2002 {
2003         enum ip_conntrack_info ctinfo;
2004         struct nf_conn *ct;
2005         int err;
2006 
2007         ct = nf_ct_get(skb, &ctinfo);
2008         if (!ct)
2009                 return 0;
2010 
2011         if (!nf_ct_is_confirmed(ct)) {
2012                 err = __nf_conntrack_update(net, skb, ct, ctinfo);
2013                 if (err < 0)
2014                         return err;
2015         }
2016 
2017         return nf_confirm_cthelper(skb, ct, ctinfo);
2018 }
2019 
2020 static bool nf_conntrack_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
2021                                        const struct sk_buff *skb)
2022 {
2023         const struct nf_conntrack_tuple *src_tuple;
2024         const struct nf_conntrack_tuple_hash *hash;
2025         struct nf_conntrack_tuple srctuple;
2026         enum ip_conntrack_info ctinfo;
2027         struct nf_conn *ct;
2028 
2029         ct = nf_ct_get(skb, &ctinfo);
2030         if (ct) {
2031                 src_tuple = nf_ct_tuple(ct, CTINFO2DIR(ctinfo));
2032                 memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2033                 return true;
2034         }
2035 
2036         if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
2037                                NFPROTO_IPV4, dev_net(skb->dev),
2038                                &srctuple))
2039                 return false;
2040 
2041         hash = nf_conntrack_find_get(dev_net(skb->dev),
2042                                      &nf_ct_zone_dflt,
2043                                      &srctuple);
2044         if (!hash)
2045                 return false;
2046 
2047         ct = nf_ct_tuplehash_to_ctrack(hash);
2048         src_tuple = nf_ct_tuple(ct, !hash->tuple.dst.dir);
2049         memcpy(dst_tuple, src_tuple, sizeof(*dst_tuple));
2050         nf_ct_put(ct);
2051 
2052         return true;
2053 }
2054 
2055 /* Bring out ya dead! */
2056 static struct nf_conn *
2057 get_next_corpse(int (*iter)(struct nf_conn *i, void *data),
2058                 void *data, unsigned int *bucket)
2059 {
2060         struct nf_conntrack_tuple_hash *h;
2061         struct nf_conn *ct;
2062         struct hlist_nulls_node *n;
2063         spinlock_t *lockp;
2064 
2065         for (; *bucket < nf_conntrack_htable_size; (*bucket)++) {
2066                 lockp = &nf_conntrack_locks[*bucket % CONNTRACK_LOCKS];
2067                 local_bh_disable();
2068                 nf_conntrack_lock(lockp);
2069                 if (*bucket < nf_conntrack_htable_size) {
2070                         hlist_nulls_for_each_entry(h, n, &nf_conntrack_hash[*bucket], hnnode) {
2071                                 if (NF_CT_DIRECTION(h) != IP_CT_DIR_ORIGINAL)
2072                                         continue;
2073                                 ct = nf_ct_tuplehash_to_ctrack(h);
2074                                 if (iter(ct, data))
2075                                         goto found;
2076                         }
2077                 }
2078                 spin_unlock(lockp);
2079                 local_bh_enable();
2080                 cond_resched();
2081         }
2082 
2083         return NULL;
2084 found:
2085         atomic_inc(&ct->ct_general.use);
2086         spin_unlock(lockp);
2087         local_bh_enable();
2088         return ct;
2089 }
2090 
2091 static void nf_ct_iterate_cleanup(int (*iter)(struct nf_conn *i, void *data),
2092                                   void *data, u32 portid, int report)
2093 {
2094         unsigned int bucket = 0, sequence;
2095         struct nf_conn *ct;
2096 
2097         might_sleep();
2098 
2099         for (;;) {
2100                 sequence = read_seqcount_begin(&nf_conntrack_generation);
2101 
2102                 while ((ct = get_next_corpse(iter, data, &bucket)) != NULL) {
2103                         /* Time to push up daises... */
2104 
2105                         nf_ct_delete(ct, portid, report);
2106                         nf_ct_put(ct);
2107                         cond_resched();
2108                 }
2109 
2110                 if (!read_seqcount_retry(&nf_conntrack_generation, sequence))
2111                         break;
2112                 bucket = 0;
2113         }
2114 }
2115 
2116 struct iter_data {
2117         int (*iter)(struct nf_conn *i, void *data);
2118         void *data;
2119         struct net *net;
2120 };
2121 
2122 static int iter_net_only(struct nf_conn *i, void *data)
2123 {
2124         struct iter_data *d = data;
2125 
2126         if (!net_eq(d->net, nf_ct_net(i)))
2127                 return 0;
2128 
2129         return d->iter(i, d->data);
2130 }
2131 
2132 static void
2133 __nf_ct_unconfirmed_destroy(struct net *net)
2134 {
2135         int cpu;
2136 
2137         for_each_possible_cpu(cpu) {
2138                 struct nf_conntrack_tuple_hash *h;
2139                 struct hlist_nulls_node *n;
2140                 struct ct_pcpu *pcpu;
2141 
2142                 pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2143 
2144                 spin_lock_bh(&pcpu->lock);
2145                 hlist_nulls_for_each_entry(h, n, &pcpu->unconfirmed, hnnode) {
2146                         struct nf_conn *ct;
2147 
2148                         ct = nf_ct_tuplehash_to_ctrack(h);
2149 
2150                         /* we cannot call iter() on unconfirmed list, the
2151                          * owning cpu can reallocate ct->ext at any time.
2152                          */
2153                         set_bit(IPS_DYING_BIT, &ct->status);
2154                 }
2155                 spin_unlock_bh(&pcpu->lock);
2156                 cond_resched();
2157         }
2158 }
2159 
2160 void nf_ct_unconfirmed_destroy(struct net *net)
2161 {
2162         might_sleep();
2163 
2164         if (atomic_read(&net->ct.count) > 0) {
2165                 __nf_ct_unconfirmed_destroy(net);
2166                 nf_queue_nf_hook_drop(net);
2167                 synchronize_net();
2168         }
2169 }
2170 EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
2171 
2172 void nf_ct_iterate_cleanup_net(struct net *net,
2173                                int (*iter)(struct nf_conn *i, void *data),
2174                                void *data, u32 portid, int report)
2175 {
2176         struct iter_data d;
2177 
2178         might_sleep();
2179 
2180         if (atomic_read(&net->ct.count) == 0)
2181                 return;
2182 
2183         d.iter = iter;
2184         d.data = data;
2185         d.net = net;
2186 
2187         nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
2188 }
2189 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
2190 
2191 /**
2192  * nf_ct_iterate_destroy - destroy unconfirmed conntracks and iterate table
2193  * @iter: callback to invoke for each conntrack
2194  * @data: data to pass to @iter
2195  *
2196  * Like nf_ct_iterate_cleanup, but first marks conntracks on the
2197  * unconfirmed list as dying (so they will not be inserted into
2198  * main table).
2199  *
2200  * Can only be called in module exit path.
2201  */
2202 void
2203 nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
2204 {
2205         struct net *net;
2206 
2207         down_read(&net_rwsem);
2208         for_each_net(net) {
2209                 if (atomic_read(&net->ct.count) == 0)
2210                         continue;
2211                 __nf_ct_unconfirmed_destroy(net);
2212                 nf_queue_nf_hook_drop(net);
2213         }
2214         up_read(&net_rwsem);
2215 
2216         /* Need to wait for netns cleanup worker to finish, if its
2217          * running -- it might have deleted a net namespace from
2218          * the global list, so our __nf_ct_unconfirmed_destroy() might
2219          * not have affected all namespaces.
2220          */
2221         net_ns_barrier();
2222 
2223         /* a conntrack could have been unlinked from unconfirmed list
2224          * before we grabbed pcpu lock in __nf_ct_unconfirmed_destroy().
2225          * This makes sure its inserted into conntrack table.
2226          */
2227         synchronize_net();
2228 
2229         nf_ct_iterate_cleanup(iter, data, 0, 0);
2230 }
2231 EXPORT_SYMBOL_GPL(nf_ct_iterate_destroy);
2232 
2233 static int kill_all(struct nf_conn *i, void *data)
2234 {
2235         return net_eq(nf_ct_net(i), data);
2236 }
2237 
2238 void nf_conntrack_cleanup_start(void)
2239 {
2240         conntrack_gc_work.exiting = true;
2241         RCU_INIT_POINTER(ip_ct_attach, NULL);
2242 }
2243 
2244 void nf_conntrack_cleanup_end(void)
2245 {
2246         RCU_INIT_POINTER(nf_ct_hook, NULL);
2247         cancel_delayed_work_sync(&conntrack_gc_work.dwork);
2248         kvfree(nf_conntrack_hash);
2249 
2250         nf_conntrack_proto_fini();
2251         nf_conntrack_seqadj_fini();
2252         nf_conntrack_labels_fini();
2253         nf_conntrack_helper_fini();
2254         nf_conntrack_timeout_fini();
2255         nf_conntrack_ecache_fini();
2256         nf_conntrack_tstamp_fini();
2257         nf_conntrack_acct_fini();
2258         nf_conntrack_expect_fini();
2259 
2260         kmem_cache_destroy(nf_conntrack_cachep);
2261 }
2262 
2263 /*
2264  * Mishearing the voices in his head, our hero wonders how he's
2265  * supposed to kill the mall.
2266  */
2267 void nf_conntrack_cleanup_net(struct net *net)
2268 {
2269         LIST_HEAD(single);
2270 
2271         list_add(&net->exit_list, &single);
2272         nf_conntrack_cleanup_net_list(&single);
2273 }
2274 
2275 void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
2276 {
2277         int busy;
2278         struct net *net;
2279 
2280         /*
2281          * This makes sure all current packets have passed through
2282          *  netfilter framework.  Roll on, two-stage module
2283          *  delete...
2284          */
2285         synchronize_net();
2286 i_see_dead_people:
2287         busy = 0;
2288         list_for_each_entry(net, net_exit_list, exit_list) {
2289                 nf_ct_iterate_cleanup(kill_all, net, 0, 0);
2290                 if (atomic_read(&net->ct.count) != 0)
2291                         busy = 1;
2292         }
2293         if (busy) {
2294                 schedule();
2295                 goto i_see_dead_people;
2296         }
2297 
2298         list_for_each_entry(net, net_exit_list, exit_list) {
2299                 nf_conntrack_proto_pernet_fini(net);
2300                 nf_conntrack_ecache_pernet_fini(net);
2301                 nf_conntrack_expect_pernet_fini(net);
2302                 free_percpu(net->ct.stat);
2303                 free_percpu(net->ct.pcpu_lists);
2304         }
2305 }
2306 
2307 void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
2308 {
2309         struct hlist_nulls_head *hash;
2310         unsigned int nr_slots, i;
2311 
2312         if (*sizep > (UINT_MAX / sizeof(struct hlist_nulls_head)))
2313                 return NULL;
2314 
2315         BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head));
2316         nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head));
2317 
2318         hash = kvmalloc_array(nr_slots, sizeof(struct hlist_nulls_head),
2319                               GFP_KERNEL | __GFP_ZERO);
2320 
2321         if (hash && nulls)
2322                 for (i = 0; i < nr_slots; i++)
2323                         INIT_HLIST_NULLS_HEAD(&hash[i], i);
2324 
2325         return hash;
2326 }
2327 EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable);
2328 
2329 int nf_conntrack_hash_resize(unsigned int hashsize)
2330 {
2331         int i, bucket;
2332         unsigned int old_size;
2333         struct hlist_nulls_head *hash, *old_hash;
2334         struct nf_conntrack_tuple_hash *h;
2335         struct nf_conn *ct;
2336 
2337         if (!hashsize)
2338                 return -EINVAL;
2339 
2340         hash = nf_ct_alloc_hashtable(&hashsize, 1);
2341         if (!hash)
2342                 return -ENOMEM;
2343 
2344         old_size = nf_conntrack_htable_size;
2345         if (old_size == hashsize) {
2346                 kvfree(hash);
2347                 return 0;
2348         }
2349 
2350         local_bh_disable();
2351         nf_conntrack_all_lock();
2352         write_seqcount_begin(&nf_conntrack_generation);
2353 
2354         /* Lookups in the old hash might happen in parallel, which means we
2355          * might get false negatives during connection lookup. New connections
2356          * created because of a false negative won't make it into the hash
2357          * though since that required taking the locks.
2358          */
2359 
2360         for (i = 0; i < nf_conntrack_htable_size; i++) {
2361                 while (!hlist_nulls_empty(&nf_conntrack_hash[i])) {
2362                         h = hlist_nulls_entry(nf_conntrack_hash[i].first,
2363                                               struct nf_conntrack_tuple_hash, hnnode);
2364                         ct = nf_ct_tuplehash_to_ctrack(h);
2365                         hlist_nulls_del_rcu(&h->hnnode);
2366                         bucket = __hash_conntrack(nf_ct_net(ct),
2367                                                   &h->tuple, hashsize);
2368                         hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]);
2369                 }
2370         }
2371         old_size = nf_conntrack_htable_size;
2372         old_hash = nf_conntrack_hash;
2373 
2374         nf_conntrack_hash = hash;
2375         nf_conntrack_htable_size = hashsize;
2376 
2377         write_seqcount_end(&nf_conntrack_generation);
2378         nf_conntrack_all_unlock();
2379         local_bh_enable();
2380 
2381         synchronize_net();
2382         kvfree(old_hash);
2383         return 0;
2384 }
2385 
2386 int nf_conntrack_set_hashsize(const char *val, const struct kernel_param *kp)
2387 {
2388         unsigned int hashsize;
2389         int rc;
2390 
2391         if (current->nsproxy->net_ns != &init_net)
2392                 return -EOPNOTSUPP;
2393 
2394         /* On boot, we can set this without any fancy locking. */
2395         if (!nf_conntrack_hash)
2396                 return param_set_uint(val, kp);
2397 
2398         rc = kstrtouint(val, 0, &hashsize);
2399         if (rc)
2400                 return rc;
2401 
2402         return nf_conntrack_hash_resize(hashsize);
2403 }
2404 EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize);
2405 
2406 static __always_inline unsigned int total_extension_size(void)
2407 {
2408         /* remember to add new extensions below */
2409         BUILD_BUG_ON(NF_CT_EXT_NUM > 9);
2410 
2411         return sizeof(struct nf_ct_ext) +
2412                sizeof(struct nf_conn_help)
2413 #if IS_ENABLED(CONFIG_NF_NAT)
2414                 + sizeof(struct nf_conn_nat)
2415 #endif
2416                 + sizeof(struct nf_conn_seqadj)
2417                 + sizeof(struct nf_conn_acct)
2418 #ifdef CONFIG_NF_CONNTRACK_EVENTS
2419                 + sizeof(struct nf_conntrack_ecache)
2420 #endif
2421 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
2422                 + sizeof(struct nf_conn_tstamp)
2423 #endif
2424 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
2425                 + sizeof(struct nf_conn_timeout)
2426 #endif
2427 #ifdef CONFIG_NF_CONNTRACK_LABELS
2428                 + sizeof(struct nf_conn_labels)
2429 #endif
2430 #if IS_ENABLED(CONFIG_NETFILTER_SYNPROXY)
2431                 + sizeof(struct nf_conn_synproxy)
2432 #endif
2433         ;
2434 };
2435 
2436 int nf_conntrack_init_start(void)
2437 {
2438         unsigned long nr_pages = totalram_pages();
2439         int max_factor = 8;
2440         int ret = -ENOMEM;
2441         int i;
2442 
2443         /* struct nf_ct_ext uses u8 to store offsets/size */
2444         BUILD_BUG_ON(total_extension_size() > 255u);
2445 
2446         seqcount_init(&nf_conntrack_generation);
2447 
2448         for (i = 0; i < CONNTRACK_LOCKS; i++)
2449                 spin_lock_init(&nf_conntrack_locks[i]);
2450 
2451         if (!nf_conntrack_htable_size) {
2452                 /* Idea from tcp.c: use 1/16384 of memory.
2453                  * On i386: 32MB machine has 512 buckets.
2454                  * >= 1GB machines have 16384 buckets.
2455                  * >= 4GB machines have 65536 buckets.
2456                  */
2457                 nf_conntrack_htable_size
2458                         = (((nr_pages << PAGE_SHIFT) / 16384)
2459                            / sizeof(struct hlist_head));
2460                 if (nr_pages > (4 * (1024 * 1024 * 1024 / PAGE_SIZE)))
2461                         nf_conntrack_htable_size = 65536;
2462                 else if (nr_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
2463                         nf_conntrack_htable_size = 16384;
2464                 if (nf_conntrack_htable_size < 32)
2465                         nf_conntrack_htable_size = 32;
2466 
2467                 /* Use a max. factor of four by default to get the same max as
2468                  * with the old struct list_heads. When a table size is given
2469                  * we use the old value of 8 to avoid reducing the max.
2470                  * entries. */
2471                 max_factor = 4;
2472         }
2473 
2474         nf_conntrack_hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size, 1);
2475         if (!nf_conntrack_hash)
2476                 return -ENOMEM;
2477 
2478         nf_conntrack_max = max_factor * nf_conntrack_htable_size;
2479 
2480         nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
2481                                                 sizeof(struct nf_conn),
2482                                                 NFCT_INFOMASK + 1,
2483                                                 SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);
2484         if (!nf_conntrack_cachep)
2485                 goto err_cachep;
2486 
2487         ret = nf_conntrack_expect_init();
2488         if (ret < 0)
2489                 goto err_expect;
2490 
2491         ret = nf_conntrack_acct_init();
2492         if (ret < 0)
2493                 goto err_acct;
2494 
2495         ret = nf_conntrack_tstamp_init();
2496         if (ret < 0)
2497                 goto err_tstamp;
2498 
2499         ret = nf_conntrack_ecache_init();
2500         if (ret < 0)
2501                 goto err_ecache;
2502 
2503         ret = nf_conntrack_timeout_init();
2504         if (ret < 0)
2505                 goto err_timeout;
2506 
2507         ret = nf_conntrack_helper_init();
2508         if (ret < 0)
2509                 goto err_helper;
2510 
2511         ret = nf_conntrack_labels_init();
2512         if (ret < 0)
2513                 goto err_labels;
2514 
2515         ret = nf_conntrack_seqadj_init();
2516         if (ret < 0)
2517                 goto err_seqadj;
2518 
2519         ret = nf_conntrack_proto_init();
2520         if (ret < 0)
2521                 goto err_proto;
2522 
2523         conntrack_gc_work_init(&conntrack_gc_work);
2524         queue_delayed_work(system_power_efficient_wq, &conntrack_gc_work.dwork, HZ);
2525 
2526         return 0;
2527 
2528 err_proto:
2529         nf_conntrack_seqadj_fini();
2530 err_seqadj:
2531         nf_conntrack_labels_fini();
2532 err_labels:
2533         nf_conntrack_helper_fini();
2534 err_helper:
2535         nf_conntrack_timeout_fini();
2536 err_timeout:
2537         nf_conntrack_ecache_fini();
2538 err_ecache:
2539         nf_conntrack_tstamp_fini();
2540 err_tstamp:
2541         nf_conntrack_acct_fini();
2542 err_acct:
2543         nf_conntrack_expect_fini();
2544 err_expect:
2545         kmem_cache_destroy(nf_conntrack_cachep);
2546 err_cachep:
2547         kvfree(nf_conntrack_hash);
2548         return ret;
2549 }
2550 
2551 static struct nf_ct_hook nf_conntrack_hook = {
2552         .update         = nf_conntrack_update,
2553         .destroy        = destroy_conntrack,
2554         .get_tuple_skb  = nf_conntrack_get_tuple_skb,
2555 };
2556 
2557 void nf_conntrack_init_end(void)
2558 {
2559         /* For use by REJECT target */
2560         RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
2561         RCU_INIT_POINTER(nf_ct_hook, &nf_conntrack_hook);
2562 }
2563 
2564 /*
2565  * We need to use special "null" values, not used in hash table
2566  */
2567 #define UNCONFIRMED_NULLS_VAL   ((1<<30)+0)
2568 #define DYING_NULLS_VAL         ((1<<30)+1)
2569 #define TEMPLATE_NULLS_VAL      ((1<<30)+2)
2570 
2571 int nf_conntrack_init_net(struct net *net)
2572 {
2573         int ret = -ENOMEM;
2574         int cpu;
2575 
2576         BUILD_BUG_ON(IP_CT_UNTRACKED == IP_CT_NUMBER);
2577         BUILD_BUG_ON_NOT_POWER_OF_2(CONNTRACK_LOCKS);
2578         atomic_set(&net->ct.count, 0);
2579 
2580         net->ct.pcpu_lists = alloc_percpu(struct ct_pcpu);
2581         if (!net->ct.pcpu_lists)
2582                 goto err_stat;
2583 
2584         for_each_possible_cpu(cpu) {
2585                 struct ct_pcpu *pcpu = per_cpu_ptr(net->ct.pcpu_lists, cpu);
2586 
2587                 spin_lock_init(&pcpu->lock);
2588                 INIT_HLIST_NULLS_HEAD(&pcpu->unconfirmed, UNCONFIRMED_NULLS_VAL);
2589                 INIT_HLIST_NULLS_HEAD(&pcpu->dying, DYING_NULLS_VAL);
2590         }
2591 
2592         net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
2593         if (!net->ct.stat)
2594                 goto err_pcpu_lists;
2595 
2596         ret = nf_conntrack_expect_pernet_init(net);
2597         if (ret < 0)
2598                 goto err_expect;
2599 
2600         nf_conntrack_acct_pernet_init(net);
2601         nf_conntrack_tstamp_pernet_init(net);
2602         nf_conntrack_ecache_pernet_init(net);
2603         nf_conntrack_helper_pernet_init(net);
2604         nf_conntrack_proto_pernet_init(net);
2605 
2606         return 0;
2607 
2608 err_expect:
2609         free_percpu(net->ct.stat);
2610 err_pcpu_lists:
2611         free_percpu(net->ct.pcpu_lists);
2612 err_stat:
2613         return ret;
2614 }
/* [<][>][^][v][top][bottom][index][help] */
root/net/netfilter/nf_conntrack_core.c

DEFINITIONS
