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
  43         switch (ctt->dst.protonum) {
  44         case IPPROTO_TCP:
  45         case IPPROTO_UDP:
  46                 ft->src_port = ctt->src.u.tcp.port;
  47                 ft->dst_port = ctt->dst.u.tcp.port;
  48                 break;
  49         }
  50 }
  51
  52 struct flow_offload *flow_offload_alloc(struct nf_conn *ct)
  53 {
  54         struct flow_offload *flow;
  55
  56         if (unlikely(nf_ct_is_dying(ct) ||
  57             !refcount_inc_not_zero(&ct->ct_general.use)))
  58                 return NULL;
  59
  60         flow = kzalloc(sizeof(*flow), GFP_ATOMIC);
  61         if (!flow)
  62                 goto err_ct_refcnt;
  63
  64         flow->ct = ct;
  65
  66         flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
  67         flow_offload_fill_dir(flow, FLOW_OFFLOAD_DIR_REPLY);
  68
  69         if (ct->status & IPS_SRC_NAT)
  70                 __set_bit(NF_FLOW_SNAT, &flow->flags);
  71         if (ct->status & IPS_DST_NAT)
  72                 __set_bit(NF_FLOW_DNAT, &flow->flags);
  73
  74         return flow;
  75
  76 err_ct_refcnt:
  77         nf_ct_put(ct);
  78
  79         return NULL;
  80 }
  81 EXPORT_SYMBOL_GPL(flow_offload_alloc);
  82
  83 static u32 flow_offload_dst_cookie(struct flow_offload_tuple *flow_tuple)
  84 {
  85         const struct rt6_info *rt;
  86
  87         if (flow_tuple->l3proto == NFPROTO_IPV6) {
  88                 rt = (const struct rt6_info *)flow_tuple->dst_cache;
  89                 return rt6_get_cookie(rt);
  90         }
  91
  92         return 0;
  93 }
  94
  95 static int flow_offload_fill_route(struct flow_offload *flow,
  96                                    const struct nf_flow_route *route,
  97                                    enum flow_offload_tuple_dir dir)
  98 {
  99         struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
 100         struct dst_entry *dst = route->tuple[dir].dst;
 101         int i, j = 0;
 102
 103         switch (flow_tuple->l3proto) {
 104         case NFPROTO_IPV4:
 105                 flow_tuple->mtu = ip_dst_mtu_maybe_forward(dst, true);
 106                 break;
 107         case NFPROTO_IPV6:
 108                 flow_tuple->mtu = ip6_dst_mtu_maybe_forward(dst, true);
 109                 break;
 110         }
 111
 112         flow_tuple->iifidx = route->tuple[dir].in.ifindex;
 113         for (i = route->tuple[dir].in.num_encaps - 1; i >= 0; i--) {
 114                 flow_tuple->encap[j].id = route->tuple[dir].in.encap[i].id;
 115                 flow_tuple->encap[j].proto = route->tuple[dir].in.encap[i].proto;
 116                 if (route->tuple[dir].in.ingress_vlans & BIT(i))
 117                         flow_tuple->in_vlan_ingress |= BIT(j);
 118                 j++;
 119         }
 120         flow_tuple->encap_num = route->tuple[dir].in.num_encaps;
 121
 122         switch (route->tuple[dir].xmit_type) {
 123         case FLOW_OFFLOAD_XMIT_DIRECT:
 124                 memcpy(flow_tuple->out.h_dest, route->tuple[dir].out.h_dest,
 125                        ETH_ALEN);
 126                 memcpy(flow_tuple->out.h_source, route->tuple[dir].out.h_source,
 127                        ETH_ALEN);
 128                 flow_tuple->out.ifidx = route->tuple[dir].out.ifindex;
 129                 flow_tuple->out.hw_ifidx = route->tuple[dir].out.hw_ifindex;
 130                 break;
 131         case FLOW_OFFLOAD_XMIT_XFRM:
 132         case FLOW_OFFLOAD_XMIT_NEIGH:
 133                 if (!dst_hold_safe(route->tuple[dir].dst))
 134                         return -1;
 135
 136                 flow_tuple->dst_cache = dst;
 137                 flow_tuple->dst_cookie = flow_offload_dst_cookie(flow_tuple);
 138                 break;
 139         default:
 140                 WARN_ON_ONCE(1);
 141                 break;
 142         }
 143         flow_tuple->xmit_type = route->tuple[dir].xmit_type;
 144
 145         return 0;
 146 }
 147
 148 static void nft_flow_dst_release(struct flow_offload *flow,
 149                                  enum flow_offload_tuple_dir dir)
 150 {
 151         if (flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_NEIGH ||
 152             flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)
 153                 dst_release(flow->tuplehash[dir].tuple.dst_cache);
 154 }
 155
 156 int flow_offload_route_init(struct flow_offload *flow,
 157                             const struct nf_flow_route *route)
 158 {
 159         int err;
 160
 161         err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_ORIGINAL);
 162         if (err < 0)
 163                 return err;
 164
 165         err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_REPLY);
 166         if (err < 0)
 167                 goto err_route_reply;
 168
 169         flow->type = NF_FLOW_OFFLOAD_ROUTE;
 170
 171         return 0;
 172
 173 err_route_reply:
 174         nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
 175
 176         return err;
 177 }
 178 EXPORT_SYMBOL_GPL(flow_offload_route_init);
 179
 180 static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
 181 {
 182         tcp->seen[0].td_maxwin = 0;
 183         tcp->seen[1].td_maxwin = 0;
 184 }
 185
 186 static void flow_offload_fixup_ct(struct nf_conn *ct)
 187 {
 188         struct net *net = nf_ct_net(ct);
 189         int l4num = nf_ct_protonum(ct);
 190         s32 timeout;
 191
 192         if (l4num == IPPROTO_TCP) {
 193                 struct nf_tcp_net *tn = nf_tcp_pernet(net);
 194
 195                 flow_offload_fixup_tcp(&ct->proto.tcp);
 196
 197                 timeout = tn->timeouts[ct->proto.tcp.state];
 198                 timeout -= tn->offload_timeout;
 199         } else if (l4num == IPPROTO_UDP) {
 200                 struct nf_udp_net *tn = nf_udp_pernet(net);
 201
 202                 timeout = tn->timeouts[UDP_CT_REPLIED];
 203                 timeout -= tn->offload_timeout;
 204         } else {
 205                 return;
 206         }
 207
 208         if (timeout < 0)
 209                 timeout = 0;
 210
 211         if (nf_flow_timeout_delta(READ_ONCE(ct->timeout)) > (__s32)timeout)
 212                 WRITE_ONCE(ct->timeout, nfct_time_stamp + timeout);
 213 }
 214
 215 static void flow_offload_route_release(struct flow_offload *flow)
 216 {
 217         nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
 218         nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_REPLY);
 219 }
 220
 221 void flow_offload_free(struct flow_offload *flow)
 222 {
 223         switch (flow->type) {
 224         case NF_FLOW_OFFLOAD_ROUTE:
 225                 flow_offload_route_release(flow);
 226                 break;
 227         default:
 228                 break;
 229         }
 230         nf_ct_put(flow->ct);
 231         kfree_rcu(flow, rcu_head);
 232 }
 233 EXPORT_SYMBOL_GPL(flow_offload_free);
 234
 235 static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
 236 {
 237         const struct flow_offload_tuple *tuple = data;
 238
 239         return jhash(tuple, offsetof(struct flow_offload_tuple, __hash), seed);
 240 }
 241
 242 static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
 243 {
 244         const struct flow_offload_tuple_rhash *tuplehash = data;
 245
 246         return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, __hash), seed);
 247 }
 248
 249 static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
 250                                         const void *ptr)
 251 {
 252         const struct flow_offload_tuple *tuple = arg->key;
 253         const struct flow_offload_tuple_rhash *x = ptr;
 254
 255         if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, __hash)))
 256                 return 1;
 257
 258         return 0;
 259 }
 260
 261 static const struct rhashtable_params nf_flow_offload_rhash_params = {
 262         .head_offset            = offsetof(struct flow_offload_tuple_rhash, node),
 263         .hashfn                 = flow_offload_hash,
 264         .obj_hashfn             = flow_offload_hash_obj,
 265         .obj_cmpfn              = flow_offload_hash_cmp,
 266         .automatic_shrinking    = true,
 267 };
 268
 269 unsigned long flow_offload_get_timeout(struct flow_offload *flow)
 270 {
 271         unsigned long timeout = NF_FLOW_TIMEOUT;
 272         struct net *net = nf_ct_net(flow->ct);
 273         int l4num = nf_ct_protonum(flow->ct);
 274
 275         if (l4num == IPPROTO_TCP) {
 276                 struct nf_tcp_net *tn = nf_tcp_pernet(net);
 277
 278                 timeout = tn->offload_timeout;
 279         } else if (l4num == IPPROTO_UDP) {
 280                 struct nf_udp_net *tn = nf_udp_pernet(net);
 281
 282                 timeout = tn->offload_timeout;
 283         }
 284
 285         return timeout;
 286 }
 287
 288 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 289 {
 290         int err;
 291
 292         flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
 293
 294         err = rhashtable_insert_fast(&flow_table->rhashtable,
 295                                      &flow->tuplehash[0].node,
 296                                      nf_flow_offload_rhash_params);
 297         if (err < 0)
 298                 return err;
 299
 300         err = rhashtable_insert_fast(&flow_table->rhashtable,
 301                                      &flow->tuplehash[1].node,
 302                                      nf_flow_offload_rhash_params);
 303         if (err < 0) {
 304                 rhashtable_remove_fast(&flow_table->rhashtable,
 305                                        &flow->tuplehash[0].node,
 306                                        nf_flow_offload_rhash_params);
 307                 return err;
 308         }
 309
 310         nf_ct_offload_timeout(flow->ct);
 311
 312         if (nf_flowtable_hw_offload(flow_table)) {
 313                 __set_bit(NF_FLOW_HW, &flow->flags);
 314                 nf_flow_offload_add(flow_table, flow);
 315         }
 316
 317         return 0;
 318 }
 319 EXPORT_SYMBOL_GPL(flow_offload_add);
 320
 321 void flow_offload_refresh(struct nf_flowtable *flow_table,
 322                           struct flow_offload *flow)
 323 {
 324         u32 timeout;
 325
 326         timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
 327         if (timeout - READ_ONCE(flow->timeout) > HZ)
 328                 WRITE_ONCE(flow->timeout, timeout);
 329         else
 330                 return;
 331
 332         if (likely(!nf_flowtable_hw_offload(flow_table)))
 333                 return;
 334
 335         nf_flow_offload_add(flow_table, flow);
 336 }
 337 EXPORT_SYMBOL_GPL(flow_offload_refresh);
 338
 339 static inline bool nf_flow_has_expired(const struct flow_offload *flow)
 340 {
 341         return nf_flow_timeout_delta(flow->timeout) <= 0;
 342 }
 343
 344 static void flow_offload_del(struct nf_flowtable *flow_table,
 345                              struct flow_offload *flow)
 346 {
 347         rhashtable_remove_fast(&flow_table->rhashtable,
 348                                &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
 349                                nf_flow_offload_rhash_params);
 350         rhashtable_remove_fast(&flow_table->rhashtable,
 351                                &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
 352                                nf_flow_offload_rhash_params);
 353         flow_offload_free(flow);
 354 }
 355
 356 void flow_offload_teardown(struct flow_offload *flow)
 357 {
 358         clear_bit(IPS_OFFLOAD_BIT, &flow->ct->status);
 359         set_bit(NF_FLOW_TEARDOWN, &flow->flags);
 360         flow_offload_fixup_ct(flow->ct);
 361 }
 362 EXPORT_SYMBOL_GPL(flow_offload_teardown);
 363
 364 struct flow_offload_tuple_rhash *
 365 flow_offload_lookup(struct nf_flowtable *flow_table,
 366                     struct flow_offload_tuple *tuple)
 367 {
 368         struct flow_offload_tuple_rhash *tuplehash;
 369         struct flow_offload *flow;
 370         int dir;
 371
 372         tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple,
 373                                       nf_flow_offload_rhash_params);
 374         if (!tuplehash)
 375                 return NULL;
 376
 377         dir = tuplehash->tuple.dir;
 378         flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 379         if (test_bit(NF_FLOW_TEARDOWN, &flow->flags))
 380                 return NULL;
 381
 382         if (unlikely(nf_ct_is_dying(flow->ct)))
 383                 return NULL;
 384
 385         return tuplehash;
 386 }
 387 EXPORT_SYMBOL_GPL(flow_offload_lookup);
 388
 389 static int
 390 nf_flow_table_iterate(struct nf_flowtable *flow_table,
 391                       void (*iter)(struct nf_flowtable *flowtable,
 392                                    struct flow_offload *flow, void *data),
 393                       void *data)
 394 {
 395         struct flow_offload_tuple_rhash *tuplehash;
 396         struct rhashtable_iter hti;
 397         struct flow_offload *flow;
 398         int err = 0;
 399
 400         rhashtable_walk_enter(&flow_table->rhashtable, &hti);
 401         rhashtable_walk_start(&hti);
 402
 403         while ((tuplehash = rhashtable_walk_next(&hti))) {
 404                 if (IS_ERR(tuplehash)) {
 405                         if (PTR_ERR(tuplehash) != -EAGAIN) {
 406                                 err = PTR_ERR(tuplehash);
 407                                 break;
 408                         }
 409                         continue;
 410                 }
 411                 if (tuplehash->tuple.dir)
 412                         continue;
 413
 414                 flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
 415
 416                 iter(flow_table, flow, data);
 417         }
 418         rhashtable_walk_stop(&hti);
 419         rhashtable_walk_exit(&hti);
 420
 421         return err;
 422 }
 423
 424 static void nf_flow_offload_gc_step(struct nf_flowtable *flow_table,
 425                                     struct flow_offload *flow, void *data)
 426 {
 427         if (nf_flow_has_expired(flow) ||
 428             nf_ct_is_dying(flow->ct))
 429                 flow_offload_teardown(flow);
 430
 431         if (test_bit(NF_FLOW_TEARDOWN, &flow->flags)) {
 432                 if (test_bit(NF_FLOW_HW, &flow->flags)) {
 433                         if (!test_bit(NF_FLOW_HW_DYING, &flow->flags))
 434                                 nf_flow_offload_del(flow_table, flow);
 435                         else if (test_bit(NF_FLOW_HW_DEAD, &flow->flags))
 436                                 flow_offload_del(flow_table, flow);
 437                 } else {
 438                         flow_offload_del(flow_table, flow);
 439                 }
 440         } else if (test_bit(NF_FLOW_HW, &flow->flags)) {
 441                 nf_flow_offload_stats(flow_table, flow);
 442         }
 443 }
 444
 445 static void nf_flow_offload_work_gc(struct work_struct *work)
 446 {
 447         struct nf_flowtable *flow_table;
 448
 449         flow_table = container_of(work, struct nf_flowtable, gc_work.work);
 450         nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
 451         queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
 452 }
 453
 454 static void nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
 455                                  __be16 port, __be16 new_port)
 456 {
 457         struct tcphdr *tcph;
 458
 459         tcph = (void *)(skb_network_header(skb) + thoff);
 460         inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false);
 461 }
 462
 463 static void nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
 464                                  __be16 port, __be16 new_port)
 465 {
 466         struct udphdr *udph;
 467
 468         udph = (void *)(skb_network_header(skb) + thoff);
 469         if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 470                 inet_proto_csum_replace2(&udph->check, skb, port,
 471                                          new_port, false);
 472                 if (!udph->check)
 473                         udph->check = CSUM_MANGLED_0;
 474         }
 475 }
 476
 477 static void nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
 478                              u8 protocol, __be16 port, __be16 new_port)
 479 {
 480         switch (protocol) {
 481         case IPPROTO_TCP:
 482                 nf_flow_nat_port_tcp(skb, thoff, port, new_port);
 483                 break;
 484         case IPPROTO_UDP:
 485                 nf_flow_nat_port_udp(skb, thoff, port, new_port);
 486                 break;
 487         }
 488 }
 489
 490 void nf_flow_snat_port(const struct flow_offload *flow,
 491                        struct sk_buff *skb, unsigned int thoff,
 492                        u8 protocol, enum flow_offload_tuple_dir dir)
 493 {
 494         struct flow_ports *hdr;
 495         __be16 port, new_port;
 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         }
 511
 512         nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 513 }
 514 EXPORT_SYMBOL_GPL(nf_flow_snat_port);
 515
 516 void nf_flow_dnat_port(const struct flow_offload *flow, struct sk_buff *skb,
 517                        unsigned int thoff, u8 protocol,
 518                        enum flow_offload_tuple_dir dir)
 519 {
 520         struct flow_ports *hdr;
 521         __be16 port, new_port;
 522
 523         hdr = (void *)(skb_network_header(skb) + thoff);
 524
 525         switch (dir) {
 526         case FLOW_OFFLOAD_DIR_ORIGINAL:
 527                 port = hdr->dest;
 528                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
 529                 hdr->dest = new_port;
 530                 break;
 531         case FLOW_OFFLOAD_DIR_REPLY:
 532                 port = hdr->source;
 533                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
 534                 hdr->source = new_port;
 535                 break;
 536         }
 537
 538         nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 539 }
 540 EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
 541
 542 int nf_flow_table_init(struct nf_flowtable *flowtable)
 543 {
 544         int err;
 545
 546         INIT_DELAYED_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
 547         flow_block_init(&flowtable->flow_block);
 548         init_rwsem(&flowtable->flow_block_lock);
 549
 550         err = rhashtable_init(&flowtable->rhashtable,
 551                               &nf_flow_offload_rhash_params);
 552         if (err < 0)
 553                 return err;
 554
 555         queue_delayed_work(system_power_efficient_wq,
 556                            &flowtable->gc_work, HZ);
 557
 558         mutex_lock(&flowtable_lock);
 559         list_add(&flowtable->list, &flowtables);
 560         mutex_unlock(&flowtable_lock);
 561
 562         return 0;
 563 }
 564 EXPORT_SYMBOL_GPL(nf_flow_table_init);
 565
 566 static void nf_flow_table_do_cleanup(struct nf_flowtable *flow_table,
 567                                      struct flow_offload *flow, void *data)
 568 {
 569         struct net_device *dev = data;
 570
 571         if (!dev) {
 572                 flow_offload_teardown(flow);
 573                 return;
 574         }
 575
 576         if (net_eq(nf_ct_net(flow->ct), dev_net(dev)) &&
 577             (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
 578              flow->tuplehash[1].tuple.iifidx == dev->ifindex))
 579                 flow_offload_teardown(flow);
 580 }
 581
 582 void nf_flow_table_gc_cleanup(struct nf_flowtable *flowtable,
 583                               struct net_device *dev)
 584 {
 585         nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
 586         flush_delayed_work(&flowtable->gc_work);
 587         nf_flow_table_offload_flush(flowtable);
 588 }
 589
 590 void nf_flow_table_cleanup(struct net_device *dev)
 591 {
 592         struct nf_flowtable *flowtable;
 593
 594         mutex_lock(&flowtable_lock);
 595         list_for_each_entry(flowtable, &flowtables, list)
 596                 nf_flow_table_gc_cleanup(flowtable, dev);
 597         mutex_unlock(&flowtable_lock);
 598 }
 599 EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
 600
 601 void nf_flow_table_free(struct nf_flowtable *flow_table)
 602 {
 603         mutex_lock(&flowtable_lock);
 604         list_del(&flow_table->list);
 605         mutex_unlock(&flowtable_lock);
 606
 607         cancel_delayed_work_sync(&flow_table->gc_work);
 608         nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
 609         nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
 610         nf_flow_table_offload_flush(flow_table);
 611         if (nf_flowtable_hw_offload(flow_table))
 612                 nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
 613         rhashtable_destroy(&flow_table->rhashtable);
 614 }
 615 EXPORT_SYMBOL_GPL(nf_flow_table_free);
 616
 617 static int __init nf_flow_table_module_init(void)
 618 {
 619         return nf_flow_table_offload_init();
 620 }
 621
 622 static void __exit nf_flow_table_module_exit(void)
 623 {
 624         nf_flow_table_offload_exit();
 625 }
 626
 627 module_init(nf_flow_table_module_init);
 628 module_exit(nf_flow_table_module_exit);
 629
 630 MODULE_LICENSE("GPL");
 631 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 632 MODULE_DESCRIPTION("Netfilter flow table module");