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             !refcount_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 u32 flow_offload_dst_cookie(struct flow_offload_tuple *flow_tuple)
  78 {
  79         const struct rt6_info *rt;
  80
  81         if (flow_tuple->l3proto == NFPROTO_IPV6) {
  82                 rt = (const struct rt6_info *)flow_tuple->dst_cache;
  83                 return rt6_get_cookie(rt);
  84         }
  85
  86         return 0;
  87 }
  88
  89 static int flow_offload_fill_route(struct flow_offload *flow,
  90                                    const struct nf_flow_route *route,
  91                                    enum flow_offload_tuple_dir dir)
  92 {
  93         struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
  94         struct dst_entry *dst = route->tuple[dir].dst;
  95         int i, j = 0;
  96
  97         switch (flow_tuple->l3proto) {
  98         case NFPROTO_IPV4:
  99                 flow_tuple->mtu = ip_dst_mtu_maybe_forward(dst, true);
 100                 break;
 101         case NFPROTO_IPV6:
 102                 flow_tuple->mtu = ip6_dst_mtu_maybe_forward(dst, true);
 103                 break;
 104         }
 105
 106         flow_tuple->iifidx = route->tuple[dir].in.ifindex;
 107         for (i = route->tuple[dir].in.num_encaps - 1; i >= 0; i--) {
 108                 flow_tuple->encap[j].id = route->tuple[dir].in.encap[i].id;
 109                 flow_tuple->encap[j].proto = route->tuple[dir].in.encap[i].proto;
 110                 if (route->tuple[dir].in.ingress_vlans & BIT(i))
 111                         flow_tuple->in_vlan_ingress |= BIT(j);
 112                 j++;
 113         }
 114         flow_tuple->encap_num = route->tuple[dir].in.num_encaps;
 115
 116         switch (route->tuple[dir].xmit_type) {
 117         case FLOW_OFFLOAD_XMIT_DIRECT:
 118                 memcpy(flow_tuple->out.h_dest, route->tuple[dir].out.h_dest,
 119                        ETH_ALEN);
 120                 memcpy(flow_tuple->out.h_source, route->tuple[dir].out.h_source,
 121                        ETH_ALEN);
 122                 flow_tuple->out.ifidx = route->tuple[dir].out.ifindex;
 123                 flow_tuple->out.hw_ifidx = route->tuple[dir].out.hw_ifindex;
 124                 break;
 125         case FLOW_OFFLOAD_XMIT_XFRM:
 126         case FLOW_OFFLOAD_XMIT_NEIGH:
 127                 if (!dst_hold_safe(route->tuple[dir].dst))
 128                         return -1;
 129
 130                 flow_tuple->dst_cache = dst;
 131                 flow_tuple->dst_cookie = flow_offload_dst_cookie(flow_tuple);
 132                 break;
 133         default:
 134                 WARN_ON_ONCE(1);
 135                 break;
 136         }
 137         flow_tuple->xmit_type = route->tuple[dir].xmit_type;
 138
 139         return 0;
 140 }
 141
 142 static void nft_flow_dst_release(struct flow_offload *flow,
 143                                  enum flow_offload_tuple_dir dir)
 144 {
 145         if (flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_NEIGH ||
 146             flow->tuplehash[dir].tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)
 147                 dst_release(flow->tuplehash[dir].tuple.dst_cache);
 148 }
 149
 150 int flow_offload_route_init(struct flow_offload *flow,
 151                             const struct nf_flow_route *route)
 152 {
 153         int err;
 154
 155         err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_ORIGINAL);
 156         if (err < 0)
 157                 return err;
 158
 159         err = flow_offload_fill_route(flow, route, FLOW_OFFLOAD_DIR_REPLY);
 160         if (err < 0)
 161                 goto err_route_reply;
 162
 163         flow->type = NF_FLOW_OFFLOAD_ROUTE;
 164
 165         return 0;
 166
 167 err_route_reply:
 168         nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
 169
 170         return err;
 171 }
 172 EXPORT_SYMBOL_GPL(flow_offload_route_init);
 173
 174 static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
 175 {
 176         tcp->seen[0].td_maxwin = 0;
 177         tcp->seen[1].td_maxwin = 0;
 178 }
 179
 180 static void flow_offload_fixup_ct(struct nf_conn *ct)
 181 {
 182         struct net *net = nf_ct_net(ct);
 183         int l4num = nf_ct_protonum(ct);
 184         s32 timeout;
 185
 186         if (l4num == IPPROTO_TCP) {
 187                 struct nf_tcp_net *tn = nf_tcp_pernet(net);
 188
 189                 flow_offload_fixup_tcp(&ct->proto.tcp);
 190
 191                 timeout = tn->timeouts[ct->proto.tcp.state];
 192                 timeout -= tn->offload_timeout;
 193         } else if (l4num == IPPROTO_UDP) {
 194                 struct nf_udp_net *tn = nf_udp_pernet(net);
 195
 196                 timeout = tn->timeouts[UDP_CT_REPLIED];
 197                 timeout -= tn->offload_timeout;
 198         } else {
 199                 return;
 200         }
 201
 202         if (timeout < 0)
 203                 timeout = 0;
 204
 205         if (nf_flow_timeout_delta(READ_ONCE(ct->timeout)) > (__s32)timeout)
 206                 WRITE_ONCE(ct->timeout, nfct_time_stamp + timeout);
 207 }
 208
 209 static void flow_offload_route_release(struct flow_offload *flow)
 210 {
 211         nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_ORIGINAL);
 212         nft_flow_dst_release(flow, FLOW_OFFLOAD_DIR_REPLY);
 213 }
 214
 215 void flow_offload_free(struct flow_offload *flow)
 216 {
 217         switch (flow->type) {
 218         case NF_FLOW_OFFLOAD_ROUTE:
 219                 flow_offload_route_release(flow);
 220                 break;
 221         default:
 222                 break;
 223         }
 224         nf_ct_put(flow->ct);
 225         kfree_rcu(flow, rcu_head);
 226 }
 227 EXPORT_SYMBOL_GPL(flow_offload_free);
 228
 229 static u32 flow_offload_hash(const void *data, u32 len, u32 seed)
 230 {
 231         const struct flow_offload_tuple *tuple = data;
 232
 233         return jhash(tuple, offsetof(struct flow_offload_tuple, __hash), seed);
 234 }
 235
 236 static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
 237 {
 238         const struct flow_offload_tuple_rhash *tuplehash = data;
 239
 240         return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, __hash), seed);
 241 }
 242
 243 static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
 244                                         const void *ptr)
 245 {
 246         const struct flow_offload_tuple *tuple = arg->key;
 247         const struct flow_offload_tuple_rhash *x = ptr;
 248
 249         if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, __hash)))
 250                 return 1;
 251
 252         return 0;
 253 }
 254
 255 static const struct rhashtable_params nf_flow_offload_rhash_params = {
 256         .head_offset            = offsetof(struct flow_offload_tuple_rhash, node),
 257         .hashfn                 = flow_offload_hash,
 258         .obj_hashfn             = flow_offload_hash_obj,
 259         .obj_cmpfn              = flow_offload_hash_cmp,
 260         .automatic_shrinking    = true,
 261 };
 262
 263 unsigned long flow_offload_get_timeout(struct flow_offload *flow)
 264 {
 265         unsigned long timeout = NF_FLOW_TIMEOUT;
 266         struct net *net = nf_ct_net(flow->ct);
 267         int l4num = nf_ct_protonum(flow->ct);
 268
 269         if (l4num == IPPROTO_TCP) {
 270                 struct nf_tcp_net *tn = nf_tcp_pernet(net);
 271
 272                 timeout = tn->offload_timeout;
 273         } else if (l4num == IPPROTO_UDP) {
 274                 struct nf_udp_net *tn = nf_udp_pernet(net);
 275
 276                 timeout = tn->offload_timeout;
 277         }
 278
 279         return timeout;
 280 }
 281
 282 int flow_offload_add(struct nf_flowtable *flow_table, struct flow_offload *flow)
 283 {
 284         int err;
 285
 286         flow->timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
 287
 288         err = rhashtable_insert_fast(&flow_table->rhashtable,
 289                                      &flow->tuplehash[0].node,
 290                                      nf_flow_offload_rhash_params);
 291         if (err < 0)
 292                 return err;
 293
 294         err = rhashtable_insert_fast(&flow_table->rhashtable,
 295                                      &flow->tuplehash[1].node,
 296                                      nf_flow_offload_rhash_params);
 297         if (err < 0) {
 298                 rhashtable_remove_fast(&flow_table->rhashtable,
 299                                        &flow->tuplehash[0].node,
 300                                        nf_flow_offload_rhash_params);
 301                 return err;
 302         }
 303
 304         nf_ct_offload_timeout(flow->ct);
 305
 306         if (nf_flowtable_hw_offload(flow_table)) {
 307                 __set_bit(NF_FLOW_HW, &flow->flags);
 308                 nf_flow_offload_add(flow_table, flow);
 309         }
 310
 311         return 0;
 312 }
 313 EXPORT_SYMBOL_GPL(flow_offload_add);
 314
 315 void flow_offload_refresh(struct nf_flowtable *flow_table,
 316                           struct flow_offload *flow)
 317 {
 318         u32 timeout;
 319
 320         timeout = nf_flowtable_time_stamp + flow_offload_get_timeout(flow);
 321         if (timeout - READ_ONCE(flow->timeout) > HZ)
 322                 WRITE_ONCE(flow->timeout, timeout);
 323         else
 324                 return;
 325
 326         if (likely(!nf_flowtable_hw_offload(flow_table)))
 327                 return;
 328
 329         nf_flow_offload_add(flow_table, flow);
 330 }
 331 EXPORT_SYMBOL_GPL(flow_offload_refresh);
 332
 333 static inline bool nf_flow_has_expired(const struct flow_offload *flow)
 334 {
 335         return nf_flow_timeout_delta(flow->timeout) <= 0;
 336 }
 337
 338 static void flow_offload_del(struct nf_flowtable *flow_table,
 339                              struct flow_offload *flow)
 340 {
 341         rhashtable_remove_fast(&flow_table->rhashtable,
 342                                &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
 343                                nf_flow_offload_rhash_params);
 344         rhashtable_remove_fast(&flow_table->rhashtable,
 345                                &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
 346                                nf_flow_offload_rhash_params);
 347         flow_offload_free(flow);
 348 }
 349
 350 void flow_offload_teardown(struct flow_offload *flow)
 351 {
 352         clear_bit(IPS_OFFLOAD_BIT, &flow->ct->status);
 353         set_bit(NF_FLOW_TEARDOWN, &flow->flags);
 354         flow_offload_fixup_ct(flow->ct);
 355 }
 356 EXPORT_SYMBOL_GPL(flow_offload_teardown);
 357
 358 struct flow_offload_tuple_rhash *
 359 flow_offload_lookup(struct nf_flowtable *flow_table,
 360                     struct flow_offload_tuple *tuple)
 361 {
 362         struct flow_offload_tuple_rhash *tuplehash;
 363         struct flow_offload *flow;
 364         int dir;
 365
 366         tuplehash = rhashtable_lookup(&flow_table->rhashtable, tuple,
 367                                       nf_flow_offload_rhash_params);
 368         if (!tuplehash)
 369                 return NULL;
 370
 371         dir = tuplehash->tuple.dir;
 372         flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
 373         if (test_bit(NF_FLOW_TEARDOWN, &flow->flags))
 374                 return NULL;
 375
 376         if (unlikely(nf_ct_is_dying(flow->ct)))
 377                 return NULL;
 378
 379         return tuplehash;
 380 }
 381 EXPORT_SYMBOL_GPL(flow_offload_lookup);
 382
 383 static int
 384 nf_flow_table_iterate(struct nf_flowtable *flow_table,
 385                       void (*iter)(struct nf_flowtable *flowtable,
 386                                    struct flow_offload *flow, void *data),
 387                       void *data)
 388 {
 389         struct flow_offload_tuple_rhash *tuplehash;
 390         struct rhashtable_iter hti;
 391         struct flow_offload *flow;
 392         int err = 0;
 393
 394         rhashtable_walk_enter(&flow_table->rhashtable, &hti);
 395         rhashtable_walk_start(&hti);
 396
 397         while ((tuplehash = rhashtable_walk_next(&hti))) {
 398                 if (IS_ERR(tuplehash)) {
 399                         if (PTR_ERR(tuplehash) != -EAGAIN) {
 400                                 err = PTR_ERR(tuplehash);
 401                                 break;
 402                         }
 403                         continue;
 404                 }
 405                 if (tuplehash->tuple.dir)
 406                         continue;
 407
 408                 flow = container_of(tuplehash, struct flow_offload, tuplehash[0]);
 409
 410                 iter(flow_table, flow, data);
 411         }
 412         rhashtable_walk_stop(&hti);
 413         rhashtable_walk_exit(&hti);
 414
 415         return err;
 416 }
 417
 418 static void nf_flow_offload_gc_step(struct nf_flowtable *flow_table,
 419                                     struct flow_offload *flow, void *data)
 420 {
 421         if (nf_flow_has_expired(flow) ||
 422             nf_ct_is_dying(flow->ct))
 423                 flow_offload_teardown(flow);
 424
 425         if (test_bit(NF_FLOW_TEARDOWN, &flow->flags)) {
 426                 if (test_bit(NF_FLOW_HW, &flow->flags)) {
 427                         if (!test_bit(NF_FLOW_HW_DYING, &flow->flags))
 428                                 nf_flow_offload_del(flow_table, flow);
 429                         else if (test_bit(NF_FLOW_HW_DEAD, &flow->flags))
 430                                 flow_offload_del(flow_table, flow);
 431                 } else {
 432                         flow_offload_del(flow_table, flow);
 433                 }
 434         } else if (test_bit(NF_FLOW_HW, &flow->flags)) {
 435                 nf_flow_offload_stats(flow_table, flow);
 436         }
 437 }
 438
 439 void nf_flow_table_gc_run(struct nf_flowtable *flow_table)
 440 {
 441         nf_flow_table_iterate(flow_table, nf_flow_offload_gc_step, NULL);
 442 }
 443
 444 static void nf_flow_offload_work_gc(struct work_struct *work)
 445 {
 446         struct nf_flowtable *flow_table;
 447
 448         flow_table = container_of(work, struct nf_flowtable, gc_work.work);
 449         nf_flow_table_gc_run(flow_table);
 450         queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
 451 }
 452
 453 static void nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
 454                                  __be16 port, __be16 new_port)
 455 {
 456         struct tcphdr *tcph;
 457
 458         tcph = (void *)(skb_network_header(skb) + thoff);
 459         inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false);
 460 }
 461
 462 static void nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
 463                                  __be16 port, __be16 new_port)
 464 {
 465         struct udphdr *udph;
 466
 467         udph = (void *)(skb_network_header(skb) + thoff);
 468         if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
 469                 inet_proto_csum_replace2(&udph->check, skb, port,
 470                                          new_port, false);
 471                 if (!udph->check)
 472                         udph->check = CSUM_MANGLED_0;
 473         }
 474 }
 475
 476 static void nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
 477                              u8 protocol, __be16 port, __be16 new_port)
 478 {
 479         switch (protocol) {
 480         case IPPROTO_TCP:
 481                 nf_flow_nat_port_tcp(skb, thoff, port, new_port);
 482                 break;
 483         case IPPROTO_UDP:
 484                 nf_flow_nat_port_udp(skb, thoff, port, new_port);
 485                 break;
 486         }
 487 }
 488
 489 void nf_flow_snat_port(const struct flow_offload *flow,
 490                        struct sk_buff *skb, unsigned int thoff,
 491                        u8 protocol, enum flow_offload_tuple_dir dir)
 492 {
 493         struct flow_ports *hdr;
 494         __be16 port, new_port;
 495
 496         hdr = (void *)(skb_network_header(skb) + thoff);
 497
 498         switch (dir) {
 499         case FLOW_OFFLOAD_DIR_ORIGINAL:
 500                 port = hdr->source;
 501                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_port;
 502                 hdr->source = new_port;
 503                 break;
 504         case FLOW_OFFLOAD_DIR_REPLY:
 505                 port = hdr->dest;
 506                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_port;
 507                 hdr->dest = new_port;
 508                 break;
 509         }
 510
 511         nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 512 }
 513 EXPORT_SYMBOL_GPL(nf_flow_snat_port);
 514
 515 void nf_flow_dnat_port(const struct flow_offload *flow, struct sk_buff *skb,
 516                        unsigned int thoff, u8 protocol,
 517                        enum flow_offload_tuple_dir dir)
 518 {
 519         struct flow_ports *hdr;
 520         __be16 port, new_port;
 521
 522         hdr = (void *)(skb_network_header(skb) + thoff);
 523
 524         switch (dir) {
 525         case FLOW_OFFLOAD_DIR_ORIGINAL:
 526                 port = hdr->dest;
 527                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_port;
 528                 hdr->dest = new_port;
 529                 break;
 530         case FLOW_OFFLOAD_DIR_REPLY:
 531                 port = hdr->source;
 532                 new_port = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_port;
 533                 hdr->source = new_port;
 534                 break;
 535         }
 536
 537         nf_flow_nat_port(skb, thoff, protocol, port, new_port);
 538 }
 539 EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
 540
 541 int nf_flow_table_init(struct nf_flowtable *flowtable)
 542 {
 543         int err;
 544
 545         INIT_DELAYED_WORK(&flowtable->gc_work, nf_flow_offload_work_gc);
 546         flow_block_init(&flowtable->flow_block);
 547         init_rwsem(&flowtable->flow_block_lock);
 548
 549         err = rhashtable_init(&flowtable->rhashtable,
 550                               &nf_flow_offload_rhash_params);
 551         if (err < 0)
 552                 return err;
 553
 554         queue_delayed_work(system_power_efficient_wq,
 555                            &flowtable->gc_work, HZ);
 556
 557         mutex_lock(&flowtable_lock);
 558         list_add(&flowtable->list, &flowtables);
 559         mutex_unlock(&flowtable_lock);
 560
 561         return 0;
 562 }
 563 EXPORT_SYMBOL_GPL(nf_flow_table_init);
 564
 565 static void nf_flow_table_do_cleanup(struct nf_flowtable *flow_table,
 566                                      struct flow_offload *flow, void *data)
 567 {
 568         struct net_device *dev = data;
 569
 570         if (!dev) {
 571                 flow_offload_teardown(flow);
 572                 return;
 573         }
 574
 575         if (net_eq(nf_ct_net(flow->ct), dev_net(dev)) &&
 576             (flow->tuplehash[0].tuple.iifidx == dev->ifindex ||
 577              flow->tuplehash[1].tuple.iifidx == dev->ifindex))
 578                 flow_offload_teardown(flow);
 579 }
 580
 581 void nf_flow_table_gc_cleanup(struct nf_flowtable *flowtable,
 582                               struct net_device *dev)
 583 {
 584         nf_flow_table_iterate(flowtable, nf_flow_table_do_cleanup, dev);
 585         flush_delayed_work(&flowtable->gc_work);
 586         nf_flow_table_offload_flush(flowtable);
 587 }
 588
 589 void nf_flow_table_cleanup(struct net_device *dev)
 590 {
 591         struct nf_flowtable *flowtable;
 592
 593         mutex_lock(&flowtable_lock);
 594         list_for_each_entry(flowtable, &flowtables, list)
 595                 nf_flow_table_gc_cleanup(flowtable, dev);
 596         mutex_unlock(&flowtable_lock);
 597 }
 598 EXPORT_SYMBOL_GPL(nf_flow_table_cleanup);
 599
 600 void nf_flow_table_free(struct nf_flowtable *flow_table)
 601 {
 602         mutex_lock(&flowtable_lock);
 603         list_del(&flow_table->list);
 604         mutex_unlock(&flowtable_lock);
 605
 606         cancel_delayed_work_sync(&flow_table->gc_work);
 607         nf_flow_table_offload_flush(flow_table);
 608         /* ... no more pending work after this stage ... */
 609         nf_flow_table_iterate(flow_table, nf_flow_table_do_cleanup, NULL);
 610         nf_flow_table_gc_run(flow_table);
 611         nf_flow_table_offload_flush_cleanup(flow_table);
 612         rhashtable_destroy(&flow_table->rhashtable);
 613 }
 614 EXPORT_SYMBOL_GPL(nf_flow_table_free);
 615
 616 static int __init nf_flow_table_module_init(void)
 617 {
 618         return nf_flow_table_offload_init();
 619 }
 620
 621 static void __exit nf_flow_table_module_exit(void)
 622 {
 623         nf_flow_table_offload_exit();
 624 }
 625
 626 module_init(nf_flow_table_module_init);
 627 module_exit(nf_flow_table_module_exit);
 628
 629 MODULE_LICENSE("GPL");
 630 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 631 MODULE_DESCRIPTION("Netfilter flow table module");