net/netfilter/nf_flow_table_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/kernel.h>
   3 #include <linux/init.h>
   4 #include <linux/module.h>
   5 #include <linux/netfilter.h>
   6 #include <linux/rhashtable.h>
   7 #include <linux/netdevice.h>
   8 #include <net/ip.h>
   9 #include <net/ip6_route.h>
  10 #include <net/netfilter/nf_tables.h>
  11 #include <net/netfilter/nf_flow_table.h>
  12 #include <net/netfilter/nf_conntrack.h>
  13 #include <net/netfilter/nf_conntrack_core.h>
  14 #include <net/netfilter/nf_conntrack_l4proto.h>
  15 #include <net/netfilter/nf_conntrack_tuple.h>
  16
  17 static DEFINE_MUTEX(flowtable_lock);
  18 static LIST_HEAD(flowtables);
  19
  20 static void
  21 flow_offload_fill_dir(struct flow_offload *flow,
  22                       enum flow_offload_tuple_dir dir)
  23 {
  24         struct flow_offload_tuple *ft = &flow->tuplehash[dir].tuple;
  25         struct nf_conntrack_tuple *ctt = &flow->ct->tuplehash[dir].tuple;
  26
  27         ft->dir = dir;
  28
  29         switch (ctt->src.l3num) {
  30         case NFPROTO_IPV4:
  31                 ft->src_v4 = ctt->src.u3.in;
  32                 ft->dst_v4 = ctt->dst.u3.in;
  33                 break;
  34         case NFPROTO_IPV6:
  35                 ft->src_v6 = ctt->src.u3.in6;
  36                 ft->dst_v6 = ctt->dst.u3.in6;
  37                 break;
  38         }
  39
  40         ft->l3proto = ctt->src.l3num;
  41         ft->l4proto = ctt->dst.protonum;
  42         ft->src_port = ctt->src.u.tcp.port;
  43         ft->dst_port = ctt->dst.u.tcp.port;
  44 }
  45
  46 struct flow_offload *flow_offload_alloc(struct nf_conn *ct)
  47 {
  48         struct flow_offload *flow;
  49
  50         if (unlikely(nf_ct_is_dying(ct) ||
  51             !atomic_inc_not_zero(&ct->ct_general.use)))
  52                 return NULL;
  53
  54         flow = kzalloc(sizeof(*flow), GFP_ATOMIC);
  55         if (!flow)
  56                 goto err_ct_refcnt;
  57
  58         flow->ct = ct;
  59
  60         flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
  61         flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_REPLY);
  62
  63         if (ct->status & IPS_SRC_NAT)
  64                 __set_bit(NF_FLOW_SNAT, &flow->flags);
  65         if (ct->status & IPS_DST_NAT)
  66                 __set_bit(NF_FLOW_DNAT, &flow->flags);
  67
  68         return flow;
  69
  70 err_ct_refcnt:
  71         nf_ct_put(ct);
  72
  73         return NULL;
  74 }
  75 EXPORT_SYMBOL_GPL(flow_offload_alloc);
  76
  77 static int flow_offload_fill_route(struct flow_offload *flow,
  78                                    const struct nf_flow_route *route,
  79                                    enum flow_offload_tuple_dir dir)
  80 {
  81         struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
  82         struct dst_entry *other_dst = route->tuple[!dir].dst;
  83         struct dst_entry *dst = route->tuple[dir].dst;
  84
  85         if (!dst_hold_safe(route->tuple[dir].dst))
  86                 return -1;
  87
  88         switch (flow_tuple->l3proto) {
  89         case NFPROTO_IPV4:
  90                 flow_tuple->mtu = ip_dst_mtu_maybe_forward(dst, true);
  91                 break;
  92         case NFPROTO_IPV6:
  93                 flow_tuple->mtu = ip6_dst_mtu_forward(dst);
  94                 break;
  95         }
  96
  97         flow_tuple->iifidx = other_dst->dev->ifindex;
  98         flow_tuple->dst_cache = dst;
  99
 100         return 0;
 101 }
 102
 103 int flow_offload_route_init(struct flow_offload *flow,
 104                             const struct nf_flow_route *route)
 105 {
 106         int err;
 107
 108         err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_ORIGINAL);
 109         if (err < 0)
 110                 return err;
 111
 112         err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_REPLY);
 113         if (err < 0)
 114                 goto err_route_reply;
 115
 116         flow->type = NF_FLOW_OFFLOAD_ROUTE;
 117
 118         return 0;
 119
 120 err_route_reply:
 121         dst_release(route->tuple[FLOW_OFFLOAD_DIR_ORIGINAL].dst);
 122
 123         return err;
 124 }
 125 EXPORT_SYMBOL_GPL(flow_offload_route_init);
 126
 127 static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
 128 {
 129         tcp->state = TCP_CONNTRACK_ESTABLISHED;
 130         tcp->seen[0].td_maxwin = 0;
 131         tcp->seen[1].td_maxwin = 0;
 132 }
 133
 134 #define NF_FLOWTABLE_TCP_PICKUP_TIMEOUT (120 * HZ)
 135 #define NF_FLOWTABLE_UDP_PICKUP_TIMEOUT (30 * HZ)
 136
 137 static void flow_offload_fixup_ct_timeout(struct nf_conn *ct)
 138 {
 139         const struct nf_conntrack_l4proto *l4proto;
 140         int l4num = nf_ct_protonum(ct);
 141         unsigned int timeout;
 142
 143         l4proto = nf_ct_l4proto_find(l4num);
 144         if (!l4proto)
 145                 return;
 146
 147         if (l4num == IPPROTO_TCP)
 148                 timeout = NF_FLOWTABLE_TCP_PICKUP_TIMEOUT;
 149         else if (l4num == IPPROTO_UDP)
 150                 timeout = NF_FLOWTABLE_UDP_PICKUP_TIMEOUT;
 151         else
 152                 return;
 153
 154         if (nf_flow_timeout_delta(ct->timeout) > (__s32)timeout)
 155                 ct->timeout = nfct_time_stamp + timeout;
 156 }
 157
 158 static void flow_offload_fixup_ct_state(struct nf_conn *ct)
 159 {
 160         if (nf_ct_protonum(ct) == IPPROTO_TCP)
 161                 flow_offload_fixup_tcp(&ct->proto.tcp);
 162 }
 163
 164 static void flow_offload_fixup_ct(struct nf_conn *ct)
 165 {
 166         flow_offload_fixup_ct_state(ct);
 167         flow_offload_fixup_ct_timeout(ct);
 168 }
 169
 170 static void flow_offload_route_release(struct flow_offload *flow)
 171 {
 172         dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
 173         dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
 174 }
 175
 176 void flow_offload_free(struct flow_offload *flow)
 177 {
 178         switch (flow->type) {
 179         case NF_FLOW_OFFLOAD_ROUTE:
 180                 flow_offload_route_release(flow);
 181                 break;
 182         default:
 183                 break;
 184         }
 185         nf_ct_put(flow->ct);
 186         kfree_rcu(flow, rcu_head);
 187 }
 188 EXPORT_SYMBOL_GPL(flow_offload_free);
 189
 190 static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
 191 {
 192         const struct flow_offload_tuple *tuple = data;
 193
 194         return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed);
 195 }
 196
 197 static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
 198 {
 199         const struct flow_offload_tuple_rhash *tuplehash = data;
 200
 201         return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed);
 202 }
 203
 204 static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
 205                                         const void *ptr)
 206 {
 207         const struct flow_offload_tuple *tuple = arg->key;
 208         const struct flow_offload_tuple_rhash *x = ptr;
 209
 210         if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir)))
 211                 return 1;
 212
 213         return 0;
 214 }
 215
 216 static const struct rhashtable_params nf_flow_offload_rhash_params = {
 217         .head_offset            = offsetof(struct flow_offload_tuple_rhash, node),
 218         .hashfn                 = flow_offload_hash,
 219         .obj_hashfn             = flow_offload_hash_obj,
 220         .obj_cmpfn              = flow_offload_hash_cmp,
 221         .automatic_shrinking    = true,
 222 };
 223
 224 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 225 {
 226         int err;
 227
 228         flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
 229
 230         err = rhashtable_insert_fast(&flow_table->rhashtable,
 231                                      &flow->tuplehash[0].node,
 232                                      nf_flow_offload_rhash_params);
 233         if (err < 0)
 234                 return err;
 235
 236         err = rhashtable_insert_fast(&flow_table->rhashtable,
 237                                      &flow->tuplehash[1].node,
 238                                      nf_flow_offload_rhash_params);
 239         if (err < 0) {
 240                 rhashtable_remove_fast(&flow_table->rhashtable,
 241                                        &flow->tuplehash[0].node,
 242                                        nf_flow_offload_rhash_params);
 243                 return err;
 244         }
 245
 246         if (nf_flowtable_hw_offload(flow_table)) {
 247                 __set_bit(NF_FLOW_HW, &flow->flags);
 248                 nf_flow_offload_add(flow_table, flow);
 249         }
 250
 251         return 0;
 252 }
 253 EXPORT_SYMBOL_GPL(flow_offload_add);
 254
 255 void flow_offload_refresh(struct nf_flowtable *flow_table,
 256                           struct flow_offload *flow)
 257 {
 258         flow->timeout = nf_flowtable_time_stamp + NF_FLOW_TIMEOUT;
 259
 260         if (likely(!nf_flowtable_hw_offload(flow_table) ||
 261                    !test_and_clear_bit(NF_FLOW_HW_REFRESH, &flow->flags)))
 262                 return;
 263
 264         nf_flow_offload_add(flow_table, flow);
 265 }
 266 EXPORT_SYMBOL_GPL(flow_offload_refresh);
 267
 268 static inline bool nf_flow_has_expired(const struct flow_offload *flow)
 269 {
 270         return nf_flow_timeout_delta(flow->timeout) <= 0;
 271 }
 272
 273 static void flow_offload_del(struct nf_flowtable *flow_table,
 274                              struct flow_offload *flow)
 275 {
 276         rhashtable_remove_fast(&flow_table->rhashtable,
 277                                &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
 278                                nf_flow_offload_rhash_params);
 279         rhashtable_remove_fast(&flow_table->rhashtable,
 280                                &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
 281                                nf_flow_offload_rhash_params);
 282
 283         clear_bit(IPS_OFFLOAD_BIT, &flow->ct->status);
 284
 285         if (nf_flow_has_expired(flow))
 286                 flow_offload_fixup_ct(flow->ct);
 287         else if (test_bit(NF_FLOW_TEARDOWN, &flow->flags))
 288                 flow_offload_fixup_ct_timeout(flow->ct);
 289
 290         flow_offload_free(flow);
 291 }
 292
 293 void flow_offload_teardown(struct flow_offload *flow)
 294 {
 295         set_bit(NF_FLOW_TEARDOWN, &flow->flags);
 296
 297         flow_offload_fixup_ct_state(flow->ct);
 298 }
 299 EXPORT_SYMBOL_GPL(flow_offload_teardown);
 300
 301 struct flow_offload_tuple_rhash *
 302 flow_offload_lookup(struct nf_flowtable *flow_table,
 303                     struct flow_offload_tuple *tuple)
 304 {
 305         struct flow_offload_tuple_rhash *tuplehash;
 306         struct flow_offload *flow;
 307         int dir;
 308
 309         tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple,
 310                                       nf_flow_offload_rhash_params);
 311         if (!tuplehash)
 312                 return NULL;
 313
 314         dir = tuplehash->tuple.dir;
 315         flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 316         if (test_bit(NF_FLOW_TEARDOWN, &flow->flags))
 317                 return NULL;
 318
 319         if (unlikely(nf_ct_is_dying(flow->ct)))
 320                 return NULL;
 321
 322         return tuplehash;
 323 }
 324 EXPORT_SYMBOL_GPL(flow_offload_lookup);
 325
 326 static int
 327 nf_flow_table_iterate(struct nf_flowtable *flow_table,
 328                       void (*iter)(struct flow_offload *flow, void *data),
 329                       void *data)
 330 {
 331         struct flow_offload_tuple_rhash *tuplehash;
 332         struct rhashtable_iter hti;
 333         struct flow_offload *flow;
 334         int err = 0;
 335
 336         rhashtable_walk_enter(&flow_table->rhashtable, &hti);
 337         rhashtable_walk_start(&hti);
 338
 339         while ((tuplehash = rhashtable_walk_next(&hti))) {
 340                 if (IS_ERR(tuplehash)) {
 341                         if (PTR_ERR(tuplehash) != -EAGAIN) {
 342                                 err = PTR_ERR(tuplehash);
 343                                 break;
 344                         }
 345                         continue;
 346                 }
 347                 if (tuplehash->tuple.dir)
 348                         continue;
 349
 350                 flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
 351
 352                 iter(flow, data);
 353         }
 354         rhashtable_walk_stop(&hti);
 355         rhashtable_walk_exit(&hti);
 356
 357         return err;
 358 }
 359
 360 static void nf_flow_offload_gc_step(struct flow_offload *flow, void *data)
 361 {
 362         struct nf_flowtable *flow_table = data;
 363
 364         if (nf_flow_has_expired(flow) || nf_ct_is_dying(flow->ct) ||
 365             test_bit(NF_FLOW_TEARDOWN, &flow->flags)) {
 366                 if (test_bit(NF_FLOW_HW, &flow->flags)) {
 367                         if (!test_bit(NF_FLOW_HW_DYING, &flow->flags))
 368                                 nf_flow_offload_del(flow_table, flow);
 369                         else if (test_bit(NF_FLOW_HW_DEAD, &flow->flags))
 370                                 flow_offload_del(flow_table, flow);
 371                 } else {
 372                         flow_offload_del(flow_table, flow);
 373                 }
 374         } else if (test_bit(NF_FLOW_HW, &flow->flags)) {
 375                 nf_flow_offload_stats(flow_table, flow);
 376         }
 377 }
 378
 379 static void nf_flow_offload_work_gc(struct work_struct *work)
 380 {
 381         struct nf_flowtable *flow_table;
 382
 383         flow_table = container_of(work, struct nf_flowtable, gc_work.work);
 384         nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
 385         queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
 386 }
 387
 388 int nf_flow_table_offload_add_cb(struct nf_flowtable *flow_table,
 389                                  flow_setup_cb_t *cb, void *cb_priv)
 390 {
 391         struct flow_block *block = &flow_table->flow_block;
 392         struct flow_block_cb *block_cb;
 393         int err = 0;
 394
 395         down_write(&flow_table->flow_block_lock);
 396         block_cb = flow_block_cb_lookup(block, cb, cb_priv);
 397         if (block_cb) {
 398                 err = -EEXIST;
 399                 goto unlock;
 400         }
 401
 402         block_cb = flow_block_cb_alloc(cb, cb_priv, cb_priv, NULL);
 403         if (IS_ERR(block_cb)) {
 404                 err = PTR_ERR(block_cb);
 405                 goto unlock;
 406         }
 407
 408         list_add_tail(&block_cb->list, &block->cb_list);
 409
 410 unlock:
 411         up_write(&flow_table->flow_block_lock);
 412         return err;
 413 }
 414 EXPORT_SYMBOL_GPL(nf_flow_table_offload_add_cb);
 415
 416 void nf_flow_table_offload_del_cb(struct nf_flowtable *flow_table,
 417                                   flow_setup_cb_t *cb, void *cb_priv)
 418 {
 419         struct flow_block *block = &flow_table->flow_block;
 420         struct flow_block_cb *block_cb;
 421
 422         down_write(&flow_table->flow_block_lock);
 423         block_cb = flow_block_cb_lookup(block, cb, cb_priv);
 424         if (block_cb) {
 425                 list_del(&block_cb->list);
 426                 flow_block_cb_free(block_cb);
 427         } else {
 428                 WARN_ON(true);
 429         }
 430         up_write(&flow_table->flow_block_lock);
 431 }
 432 EXPORT_SYMBOL_GPL(nf_flow_table_offload_del_cb);
 433
 434 static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
 435                                 __be16 port, __be16 new_port)
 436 {
 437         struct tcphdr *tcph;
 438
 439         if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
 440             skb_try_make_writable(skb, thoff + sizeof(*tcph)))
 441                 return -1;
 442
 443         tcph = (void *)(skb_network_header(skb) + thoff);
 444         inet_proto_csum_replace2(&tcph->check, skb, port, new_port, true);
 445
 446         return 0;
 447 }
 448
 449 static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
 450                                 __be16 port, __be16 new_port)
 451 {
 452         struct udphdr *udph;
 453
 454         if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
 455             skb_try_make_writable(skb, thoff + sizeof(*udph)))
 456                 return -1;
 457
 458         udph = (void *)(skb_network_header(skb) + thoff);
 459         if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 460                 inet_proto_csum_replace2(&udph->check, skb, port,
 461                                          new_port, true);
 462                 if (!udph->check)
 463                         udph->check = CSUM_MANGLED_0;
 464         }
 465
 466         return 0;
 467 }
 468
 469 static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
 470                             u8 protocol, __be16 port, __be16 new_port)
 471 {
 472         switch (protocol) {
 473         case IPPROTO_TCP:
 474                 if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
 475                         return NF_DROP;
 476                 break;
 477         case IPPROTO_UDP:
 478                 if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
 479                         return NF_DROP;
 480                 break;
 481         }
 482
 483         return 0;
 484 }
 485
 486 int nf_flow_snat_port(const struct flow_offload *flow,
 487                       struct sk_buff *skb, unsigned int thoff,
 488                       u8 protocol, enum flow_offload_tuple_dir dir)
 489 {
 490         struct flow_ports *hdr;
 491         __be16 port, new_port;
 492
 493         if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
 494             skb_try_make_writable(skb, thoff + sizeof(*hdr)))
 495                 return -1;
 496
 497         hdr = (void *)(skb_network_header(skb) + thoff);
 498
 499         switch (dir) {
 500         case FLOW_OFFLOAD_DIR_ORIGINAL:
 501                 port = hdr->source;
 502                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
 503                 hdr->source = new_port;
 504                 break;
 505         case FLOW_OFFLOAD_DIR_REPLY:
 506                 port = hdr->dest;
 507                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
 508                 hdr->dest = new_port;
 509                 break;
 510         default:
 511                 return -1;
 512         }
 513
 514         return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 515 }
 516 EXPORT_SYMBOL_GPL(nf_flow_snat_port);
 517
 518 int nf_flow_dnat_port(const struct flow_offload *flow,
 519                       struct sk_buff *skb, unsigned int thoff,
 520                       u8 protocol, enum flow_offload_tuple_dir dir)
 521 {
 522         struct flow_ports *hdr;
 523         __be16 port, new_port;
 524
 525         if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
 526             skb_try_make_writable(skb, thoff + sizeof(*hdr)))
 527                 return -1;
 528
 529         hdr = (void *)(skb_network_header(skb) + thoff);
 530
 531         switch (dir) {
 532         case FLOW_OFFLOAD_DIR_ORIGINAL:
 533                 port = hdr->dest;
 534                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
 535                 hdr->dest = new_port;
 536                 break;
 537         case FLOW_OFFLOAD_DIR_REPLY:
 538                 port = hdr->source;
 539                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
 540                 hdr->source = new_port;
 541                 break;
 542         default:
 543                 return -1;
 544         }
 545
 546         return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 547 }
 548 EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
 549
 550 int nf_flow_table_init(struct nf_flowtable *flowtable)
 551 {
 552         int err;
 553
 554         INIT_DEFERRABLE_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
 555         flow_block_init(&flowtable->flow_block);
 556         init_rwsem(&flowtable->flow_block_lock);
 557
 558         err = rhashtable_init(&flowtable->rhashtable,
 559                               &nf_flow_offload_rhash_params);
 560         if (err < 0)
 561                 return err;
 562
 563         queue_delayed_work(system_power_efficient_wq,
 564                            &flowtable->gc_work, HZ);
 565
 566         mutex_lock(&flowtable_lock);
 567         list_add(&flowtable->list, &flowtables);
 568         mutex_unlock(&flowtable_lock);
 569
 570         return 0;
 571 }
 572 EXPORT_SYMBOL_GPL(nf_flow_table_init);
 573
 574 static void nf_flow_table_do_cleanup(struct flow_offload *flow, void *data)
 575 {
 576         struct net_device *dev = data;
 577
 578         if (!dev) {
 579                 flow_offload_teardown(flow);
 580                 return;
 581         }
 582
 583         if (net_eq(nf_ct_net(flow->ct), dev_net(dev)) &&
 584             (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
 585              flow->tuplehash[1].tuple.iifidx == dev->ifindex))
 586                 flow_offload_teardown(flow);
 587 }
 588
 589 static void nf_flow_table_iterate_cleanup(struct nf_flowtable *flowtable,
 590                                           struct net_device *dev)
 591 {
 592         nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
 593         flush_delayed_work(&flowtable->gc_work);
 594         nf_flow_table_offload_flush(flowtable);
 595 }
 596
 597 void nf_flow_table_cleanup(struct net_device *dev)
 598 {
 599         struct nf_flowtable *flowtable;
 600
 601         mutex_lock(&flowtable_lock);
 602         list_for_each_entry(flowtable, &flowtables, list)
 603                 nf_flow_table_iterate_cleanup(flowtable, dev);
 604         mutex_unlock(&flowtable_lock);
 605 }
 606 EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
 607
 608 void nf_flow_table_free(struct nf_flowtable *flow_table)
 609 {
 610         mutex_lock(&flowtable_lock);
 611         list_del(&flow_table->list);
 612         mutex_unlock(&flowtable_lock);
 613
 614         cancel_delayed_work_sync(&flow_table->gc_work);
 615         nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
 616         nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, flow_table);
 617         nf_flow_table_offload_flush(flow_table);
 618         if (nf_flowtable_hw_offload(flow_table))
 619                 nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step,
 620                                       flow_table);
 621         rhashtable_destroy(&flow_table->rhashtable);
 622 }
 623 EXPORT_SYMBOL_GPL(nf_flow_table_free);
 624
 625 static int __init nf_flow_table_module_init(void)
 626 {
 627         return nf_flow_table_offload_init();
 628 }
 629
 630 static void __exit nf_flow_table_module_exit(void)
 631 {
 632         nf_flow_table_offload_exit();
 633 }
 634
 635 module_init(nf_flow_table_module_init);
 636 module_exit(nf_flow_table_module_exit);
 637
 638 MODULE_LICENSE("GPL");
 639 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");