net/netfilter/nft_set_hash.c

   1 /*
   2  * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/list.h>
  15 #include <linux/log2.h>
  16 #include <linux/jhash.h>
  17 #include <linux/netlink.h>
  18 #include <linux/workqueue.h>
  19 #include <linux/rhashtable.h>
  20 #include <linux/netfilter.h>
  21 #include <linux/netfilter/nf_tables.h>
  22 #include <net/netfilter/nf_tables.h>
  23
  24 /* We target a hash table size of 4, element hint is 75% of final size */
  25 #define NFT_RHASH_ELEMENT_HINT 3
  26
  27 struct nft_rhash {
  28         struct rhashtable               ht;
  29         struct delayed_work             gc_work;
  30 };
  31
  32 struct nft_rhash_elem {
  33         struct rhash_head               node;
  34         struct nft_set_ext              ext;
  35 };
  36
  37 struct nft_rhash_cmp_arg {
  38         const struct nft_set            *set;
  39         const u32                       *key;
  40         u8                              genmask;
  41 };
  42
  43 static inline u32 nft_rhash_key(const void *data, u32 len, u32 seed)
  44 {
  45         const struct nft_rhash_cmp_arg *arg = data;
  46
  47         return jhash(arg->key, len, seed);
  48 }
  49
  50 static inline u32 nft_rhash_obj(const void *data, u32 len, u32 seed)
  51 {
  52         const struct nft_rhash_elem *he = data;
  53
  54         return jhash(nft_set_ext_key(&he->ext), len, seed);
  55 }
  56
  57 static inline int nft_rhash_cmp(struct rhashtable_compare_arg *arg,
  58                                 const void *ptr)
  59 {
  60         const struct nft_rhash_cmp_arg *x = arg->key;
  61         const struct nft_rhash_elem *he = ptr;
  62
  63         if (memcmp(nft_set_ext_key(&he->ext), x->key, x->set->klen))
  64                 return 1;
  65         if (nft_set_elem_expired(&he->ext))
  66                 return 1;
  67         if (!nft_set_elem_active(&he->ext, x->genmask))
  68                 return 1;
  69         return 0;
  70 }
  71
  72 static const struct rhashtable_params nft_rhash_params = {
  73         .head_offset            = offsetof(struct nft_rhash_elem, node),
  74         .hashfn                 = nft_rhash_key,
  75         .obj_hashfn             = nft_rhash_obj,
  76         .obj_cmpfn              = nft_rhash_cmp,
  77         .automatic_shrinking    = true,
  78 };
  79
  80 static bool nft_rhash_lookup(const struct net *net, const struct nft_set *set,
  81                              const u32 *key, const struct nft_set_ext **ext)
  82 {
  83         struct nft_rhash *priv = nft_set_priv(set);
  84         const struct nft_rhash_elem *he;
  85         struct nft_rhash_cmp_arg arg = {
  86                 .genmask = nft_genmask_cur(net),
  87                 .set     = set,
  88                 .key     = key,
  89         };
  90
  91         he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params);
  92         if (he != NULL)
  93                 *ext = &he->ext;
  94
  95         return !!he;
  96 }
  97
  98 static bool nft_rhash_update(struct nft_set *set, const u32 *key,
  99                              void *(*new)(struct nft_set *,
 100                                           const struct nft_expr *,
 101                                           struct nft_regs *regs),
 102                              const struct nft_expr *expr,
 103                              struct nft_regs *regs,
 104                              const struct nft_set_ext **ext)
 105 {
 106         struct nft_rhash *priv = nft_set_priv(set);
 107         struct nft_rhash_elem *he, *prev;
 108         struct nft_rhash_cmp_arg arg = {
 109                 .genmask = NFT_GENMASK_ANY,
 110                 .set     = set,
 111                 .key     = key,
 112         };
 113
 114         he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params);
 115         if (he != NULL)
 116                 goto out;
 117
 118         he = new(set, expr, regs);
 119         if (he == NULL)
 120                 goto err1;
 121
 122         prev = rhashtable_lookup_get_insert_key(&priv->ht, &arg, &he->node,
 123                                                 nft_rhash_params);
 124         if (IS_ERR(prev))
 125                 goto err2;
 126
 127         /* Another cpu may race to insert the element with the same key */
 128         if (prev) {
 129                 nft_set_elem_destroy(set, he, true);
 130                 he = prev;
 131         }
 132
 133 out:
 134         *ext = &he->ext;
 135         return true;
 136
 137 err2:
 138         nft_set_elem_destroy(set, he, true);
 139 err1:
 140         return false;
 141 }
 142
 143 static int nft_rhash_insert(const struct net *net, const struct nft_set *set,
 144                             const struct nft_set_elem *elem,
 145                             struct nft_set_ext **ext)
 146 {
 147         struct nft_rhash *priv = nft_set_priv(set);
 148         struct nft_rhash_elem *he = elem->priv;
 149         struct nft_rhash_cmp_arg arg = {
 150                 .genmask = nft_genmask_next(net),
 151                 .set     = set,
 152                 .key     = elem->key.val.data,
 153         };
 154         struct nft_rhash_elem *prev;
 155
 156         prev = rhashtable_lookup_get_insert_key(&priv->ht, &arg, &he->node,
 157                                                 nft_rhash_params);
 158         if (IS_ERR(prev))
 159                 return PTR_ERR(prev);
 160         if (prev) {
 161                 *ext = &prev->ext;
 162                 return -EEXIST;
 163         }
 164         return 0;
 165 }
 166
 167 static void nft_rhash_activate(const struct net *net, const struct nft_set *set,
 168                                const struct nft_set_elem *elem)
 169 {
 170         struct nft_rhash_elem *he = elem->priv;
 171
 172         nft_set_elem_change_active(net, set, &he->ext);
 173         nft_set_elem_clear_busy(&he->ext);
 174 }
 175
 176 static bool nft_rhash_flush(const struct net *net,
 177                             const struct nft_set *set, void *priv)
 178 {
 179         struct nft_rhash_elem *he = priv;
 180
 181         if (!nft_set_elem_mark_busy(&he->ext) ||
 182             !nft_is_active(net, &he->ext)) {
 183                 nft_set_elem_change_active(net, set, &he->ext);
 184                 return true;
 185         }
 186         return false;
 187 }
 188
 189 static void *nft_rhash_deactivate(const struct net *net,
 190                                   const struct nft_set *set,
 191                                   const struct nft_set_elem *elem)
 192 {
 193         struct nft_rhash *priv = nft_set_priv(set);
 194         struct nft_rhash_elem *he;
 195         struct nft_rhash_cmp_arg arg = {
 196                 .genmask = nft_genmask_next(net),
 197                 .set     = set,
 198                 .key     = elem->key.val.data,
 199         };
 200
 201         rcu_read_lock();
 202         he = rhashtable_lookup_fast(&priv->ht, &arg, nft_rhash_params);
 203         if (he != NULL &&
 204             !nft_rhash_flush(net, set, he))
 205                 he = NULL;
 206
 207         rcu_read_unlock();
 208
 209         return he;
 210 }
 211
 212 static void nft_rhash_remove(const struct net *net,
 213                              const struct nft_set *set,
 214                              const struct nft_set_elem *elem)
 215 {
 216         struct nft_rhash *priv = nft_set_priv(set);
 217         struct nft_rhash_elem *he = elem->priv;
 218
 219         rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params);
 220 }
 221
 222 static void nft_rhash_walk(const struct nft_ctx *ctx, struct nft_set *set,
 223                            struct nft_set_iter *iter)
 224 {
 225         struct nft_rhash *priv = nft_set_priv(set);
 226         struct nft_rhash_elem *he;
 227         struct rhashtable_iter hti;
 228         struct nft_set_elem elem;
 229         int err;
 230
 231         err = rhashtable_walk_init(&priv->ht, &hti, GFP_ATOMIC);
 232         iter->err = err;
 233         if (err)
 234                 return;
 235
 236         err = rhashtable_walk_start(&hti);
 237         if (err && err != -EAGAIN) {
 238                 iter->err = err;
 239                 goto out;
 240         }
 241
 242         while ((he = rhashtable_walk_next(&hti))) {
 243                 if (IS_ERR(he)) {
 244                         err = PTR_ERR(he);
 245                         if (err != -EAGAIN) {
 246                                 iter->err = err;
 247                                 goto out;
 248                         }
 249
 250                         continue;
 251                 }
 252
 253                 if (iter->count < iter->skip)
 254                         goto cont;
 255                 if (nft_set_elem_expired(&he->ext))
 256                         goto cont;
 257                 if (!nft_set_elem_active(&he->ext, iter->genmask))
 258                         goto cont;
 259
 260                 elem.priv = he;
 261
 262                 iter->err = iter->fn(ctx, set, iter, &elem);
 263                 if (iter->err < 0)
 264                         goto out;
 265
 266 cont:
 267                 iter->count++;
 268         }
 269
 270 out:
 271         rhashtable_walk_stop(&hti);
 272         rhashtable_walk_exit(&hti);
 273 }
 274
 275 static void nft_rhash_gc(struct work_struct *work)
 276 {
 277         struct nft_set *set;
 278         struct nft_rhash_elem *he;
 279         struct nft_rhash *priv;
 280         struct nft_set_gc_batch *gcb = NULL;
 281         struct rhashtable_iter hti;
 282         int err;
 283
 284         priv = container_of(work, struct nft_rhash, gc_work.work);
 285         set  = nft_set_container_of(priv);
 286
 287         err = rhashtable_walk_init(&priv->ht, &hti, GFP_KERNEL);
 288         if (err)
 289                 goto schedule;
 290
 291         err = rhashtable_walk_start(&hti);
 292         if (err && err != -EAGAIN)
 293                 goto out;
 294
 295         while ((he = rhashtable_walk_next(&hti))) {
 296                 if (IS_ERR(he)) {
 297                         if (PTR_ERR(he) != -EAGAIN)
 298                                 goto out;
 299                         continue;
 300                 }
 301
 302                 if (!nft_set_elem_expired(&he->ext))
 303                         continue;
 304                 if (nft_set_elem_mark_busy(&he->ext))
 305                         continue;
 306
 307                 gcb = nft_set_gc_batch_check(set, gcb, GFP_ATOMIC);
 308                 if (gcb == NULL)
 309                         goto out;
 310                 rhashtable_remove_fast(&priv->ht, &he->node, nft_rhash_params);
 311                 atomic_dec(&set->nelems);
 312                 nft_set_gc_batch_add(gcb, he);
 313         }
 314 out:
 315         rhashtable_walk_stop(&hti);
 316         rhashtable_walk_exit(&hti);
 317
 318         nft_set_gc_batch_complete(gcb);
 319 schedule:
 320         queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
 321                            nft_set_gc_interval(set));
 322 }
 323
 324 static unsigned int nft_rhash_privsize(const struct nlattr * const nla[],
 325                                        const struct nft_set_desc *desc)
 326 {
 327         return sizeof(struct nft_rhash);
 328 }
 329
 330 static int nft_rhash_init(const struct nft_set *set,
 331                           const struct nft_set_desc *desc,
 332                           const struct nlattr * const tb[])
 333 {
 334         struct nft_rhash *priv = nft_set_priv(set);
 335         struct rhashtable_params params = nft_rhash_params;
 336         int err;
 337
 338         params.nelem_hint = desc->size ?: NFT_RHASH_ELEMENT_HINT;
 339         params.key_len    = set->klen;
 340
 341         err = rhashtable_init(&priv->ht, &params);
 342         if (err < 0)
 343                 return err;
 344
 345         INIT_DEFERRABLE_WORK(&priv->gc_work, nft_rhash_gc);
 346         if (set->flags & NFT_SET_TIMEOUT)
 347                 queue_delayed_work(system_power_efficient_wq, &priv->gc_work,
 348                                    nft_set_gc_interval(set));
 349         return 0;
 350 }
 351
 352 static void nft_rhash_elem_destroy(void *ptr, void *arg)
 353 {
 354         nft_set_elem_destroy(arg, ptr, true);
 355 }
 356
 357 static void nft_rhash_destroy(const struct nft_set *set)
 358 {
 359         struct nft_rhash *priv = nft_set_priv(set);
 360
 361         cancel_delayed_work_sync(&priv->gc_work);
 362         rhashtable_free_and_destroy(&priv->ht, nft_rhash_elem_destroy,
 363                                     (void *)set);
 364 }
 365
 366 static u32 nft_hash_buckets(u32 size)
 367 {
 368         return roundup_pow_of_two(size * 4 / 3);
 369 }
 370
 371 static bool nft_rhash_estimate(const struct nft_set_desc *desc, u32 features,
 372                                struct nft_set_estimate *est)
 373 {
 374         est->size   = ~0;
 375         est->lookup = NFT_SET_CLASS_O_1;
 376         est->space  = NFT_SET_CLASS_O_N;
 377
 378         return true;
 379 }
 380
 381 struct nft_hash {
 382         u32                             seed;
 383         u32                             buckets;
 384         struct hlist_head               table[];
 385 };
 386
 387 struct nft_hash_elem {
 388         struct hlist_node               node;
 389         struct nft_set_ext              ext;
 390 };
 391
 392 static bool nft_hash_lookup(const struct net *net, const struct nft_set *set,
 393                             const u32 *key, const struct nft_set_ext **ext)
 394 {
 395         struct nft_hash *priv = nft_set_priv(set);
 396         u8 genmask = nft_genmask_cur(net);
 397         const struct nft_hash_elem *he;
 398         u32 hash;
 399
 400         hash = jhash(key, set->klen, priv->seed);
 401         hash = reciprocal_scale(hash, priv->buckets);
 402         hlist_for_each_entry_rcu(he, &priv->table[hash], node) {
 403                 if (!memcmp(nft_set_ext_key(&he->ext), key, set->klen) &&
 404                     nft_set_elem_active(&he->ext, genmask)) {
 405                         *ext = &he->ext;
 406                         return true;
 407                 }
 408         }
 409         return false;
 410 }
 411
 412 /* nft_hash_select_ops() makes sure key size can be either 2 or 4 bytes . */
 413 static inline u32 nft_hash_key(const u32 *key, u32 klen)
 414 {
 415         if (klen == 4)
 416                 return *key;
 417
 418         return *(u16 *)key;
 419 }
 420
 421 static bool nft_hash_lookup_fast(const struct net *net,
 422                                  const struct nft_set *set,
 423                                  const u32 *key, const struct nft_set_ext **ext)
 424 {
 425         struct nft_hash *priv = nft_set_priv(set);
 426         u8 genmask = nft_genmask_cur(net);
 427         const struct nft_hash_elem *he;
 428         u32 hash, k1, k2;
 429
 430         k1 = nft_hash_key(key, set->klen);
 431         hash = jhash_1word(k1, priv->seed);
 432         hash = reciprocal_scale(hash, priv->buckets);
 433         hlist_for_each_entry_rcu(he, &priv->table[hash], node) {
 434                 k2 = nft_hash_key(nft_set_ext_key(&he->ext)->data, set->klen);
 435                 if (k1 == k2 &&
 436                     nft_set_elem_active(&he->ext, genmask)) {
 437                         *ext = &he->ext;
 438                         return true;
 439                 }
 440         }
 441         return false;
 442 }
 443
 444 static int nft_hash_insert(const struct net *net, const struct nft_set *set,
 445                            const struct nft_set_elem *elem,
 446                            struct nft_set_ext **ext)
 447 {
 448         struct nft_hash_elem *this = elem->priv, *he;
 449         struct nft_hash *priv = nft_set_priv(set);
 450         u8 genmask = nft_genmask_next(net);
 451         u32 hash;
 452
 453         hash = jhash(nft_set_ext_key(&this->ext), set->klen, priv->seed);
 454         hash = reciprocal_scale(hash, priv->buckets);
 455         hlist_for_each_entry(he, &priv->table[hash], node) {
 456                 if (!memcmp(nft_set_ext_key(&this->ext),
 457                             nft_set_ext_key(&he->ext), set->klen) &&
 458                     nft_set_elem_active(&he->ext, genmask)) {
 459                         *ext = &he->ext;
 460                         return -EEXIST;
 461                 }
 462         }
 463         hlist_add_head_rcu(&this->node, &priv->table[hash]);
 464         return 0;
 465 }
 466
 467 static void nft_hash_activate(const struct net *net, const struct nft_set *set,
 468                               const struct nft_set_elem *elem)
 469 {
 470         struct nft_hash_elem *he = elem->priv;
 471
 472         nft_set_elem_change_active(net, set, &he->ext);
 473 }
 474
 475 static bool nft_hash_flush(const struct net *net,
 476                            const struct nft_set *set, void *priv)
 477 {
 478         struct nft_hash_elem *he = priv;
 479
 480         nft_set_elem_change_active(net, set, &he->ext);
 481         return true;
 482 }
 483
 484 static void *nft_hash_deactivate(const struct net *net,
 485                                  const struct nft_set *set,
 486                                  const struct nft_set_elem *elem)
 487 {
 488         struct nft_hash *priv = nft_set_priv(set);
 489         struct nft_hash_elem *this = elem->priv, *he;
 490         u8 genmask = nft_genmask_next(net);
 491         u32 hash;
 492
 493         hash = jhash(nft_set_ext_key(&this->ext), set->klen, priv->seed);
 494         hash = reciprocal_scale(hash, priv->buckets);
 495         hlist_for_each_entry(he, &priv->table[hash], node) {
 496                 if (!memcmp(nft_set_ext_key(&this->ext), &elem->key.val,
 497                             set->klen) ||
 498                     nft_set_elem_active(&he->ext, genmask)) {
 499                         nft_set_elem_change_active(net, set, &he->ext);
 500                         return he;
 501                 }
 502         }
 503         return NULL;
 504 }
 505
 506 static void nft_hash_remove(const struct net *net,
 507                             const struct nft_set *set,
 508                             const struct nft_set_elem *elem)
 509 {
 510         struct nft_hash_elem *he = elem->priv;
 511
 512         hlist_del_rcu(&he->node);
 513 }
 514
 515 static void nft_hash_walk(const struct nft_ctx *ctx, struct nft_set *set,
 516                           struct nft_set_iter *iter)
 517 {
 518         struct nft_hash *priv = nft_set_priv(set);
 519         struct nft_hash_elem *he;
 520         struct nft_set_elem elem;
 521         int i;
 522
 523         for (i = 0; i < priv->buckets; i++) {
 524                 hlist_for_each_entry_rcu(he, &priv->table[i], node) {
 525                         if (iter->count < iter->skip)
 526                                 goto cont;
 527                         if (!nft_set_elem_active(&he->ext, iter->genmask))
 528                                 goto cont;
 529
 530                         elem.priv = he;
 531
 532                         iter->err = iter->fn(ctx, set, iter, &elem);
 533                         if (iter->err < 0)
 534                                 return;
 535 cont:
 536                         iter->count++;
 537                 }
 538         }
 539 }
 540
 541 static unsigned int nft_hash_privsize(const struct nlattr * const nla[],
 542                                       const struct nft_set_desc *desc)
 543 {
 544         return sizeof(struct nft_hash) +
 545                nft_hash_buckets(desc->size) * sizeof(struct hlist_head);
 546 }
 547
 548 static int nft_hash_init(const struct nft_set *set,
 549                          const struct nft_set_desc *desc,
 550                          const struct nlattr * const tb[])
 551 {
 552         struct nft_hash *priv = nft_set_priv(set);
 553
 554         priv->buckets = nft_hash_buckets(desc->size);
 555         get_random_bytes(&priv->seed, sizeof(priv->seed));
 556
 557         return 0;
 558 }
 559
 560 static void nft_hash_destroy(const struct nft_set *set)
 561 {
 562         struct nft_hash *priv = nft_set_priv(set);
 563         struct nft_hash_elem *he;
 564         struct hlist_node *next;
 565         int i;
 566
 567         for (i = 0; i < priv->buckets; i++) {
 568                 hlist_for_each_entry_safe(he, next, &priv->table[i], node) {
 569                         hlist_del_rcu(&he->node);
 570                         nft_set_elem_destroy(set, he, true);
 571                 }
 572         }
 573 }
 574
 575 static bool nft_hash_estimate(const struct nft_set_desc *desc, u32 features,
 576                               struct nft_set_estimate *est)
 577 {
 578         est->size   = sizeof(struct nft_hash) +
 579                       nft_hash_buckets(desc->size) * sizeof(struct hlist_head) +
 580                       desc->size * sizeof(struct nft_hash_elem);
 581         est->lookup = NFT_SET_CLASS_O_1;
 582         est->space  = NFT_SET_CLASS_O_N;
 583
 584         return true;
 585 }
 586
 587 static struct nft_set_type nft_hash_type;
 588 static struct nft_set_ops nft_rhash_ops __read_mostly = {
 589         .type           = &nft_hash_type,
 590         .privsize       = nft_rhash_privsize,
 591         .elemsize       = offsetof(struct nft_rhash_elem, ext),
 592         .estimate       = nft_rhash_estimate,
 593         .init           = nft_rhash_init,
 594         .destroy        = nft_rhash_destroy,
 595         .insert         = nft_rhash_insert,
 596         .activate       = nft_rhash_activate,
 597         .deactivate     = nft_rhash_deactivate,
 598         .flush          = nft_rhash_flush,
 599         .remove         = nft_rhash_remove,
 600         .lookup         = nft_rhash_lookup,
 601         .update         = nft_rhash_update,
 602         .walk           = nft_rhash_walk,
 603         .features       = NFT_SET_MAP | NFT_SET_OBJECT | NFT_SET_TIMEOUT,
 604 };
 605
 606 static struct nft_set_ops nft_hash_ops __read_mostly = {
 607         .type           = &nft_hash_type,
 608         .privsize       = nft_hash_privsize,
 609         .elemsize       = offsetof(struct nft_hash_elem, ext),
 610         .estimate       = nft_hash_estimate,
 611         .init           = nft_hash_init,
 612         .destroy        = nft_hash_destroy,
 613         .insert         = nft_hash_insert,
 614         .activate       = nft_hash_activate,
 615         .deactivate     = nft_hash_deactivate,
 616         .flush          = nft_hash_flush,
 617         .remove         = nft_hash_remove,
 618         .lookup         = nft_hash_lookup,
 619         .walk           = nft_hash_walk,
 620         .features       = NFT_SET_MAP | NFT_SET_OBJECT,
 621 };
 622
 623 static struct nft_set_ops nft_hash_fast_ops __read_mostly = {
 624         .type           = &nft_hash_type,
 625         .privsize       = nft_hash_privsize,
 626         .elemsize       = offsetof(struct nft_hash_elem, ext),
 627         .estimate       = nft_hash_estimate,
 628         .init           = nft_hash_init,
 629         .destroy        = nft_hash_destroy,
 630         .insert         = nft_hash_insert,
 631         .activate       = nft_hash_activate,
 632         .deactivate     = nft_hash_deactivate,
 633         .flush          = nft_hash_flush,
 634         .remove         = nft_hash_remove,
 635         .lookup         = nft_hash_lookup_fast,
 636         .walk           = nft_hash_walk,
 637         .features       = NFT_SET_MAP | NFT_SET_OBJECT,
 638 };
 639
 640 static const struct nft_set_ops *
 641 nft_hash_select_ops(const struct nft_ctx *ctx, const struct nft_set_desc *desc,
 642                     u32 flags)
 643 {
 644         if (desc->size) {
 645                 switch (desc->klen) {
 646                 case 2:
 647                 case 4:
 648                         return &nft_hash_fast_ops;
 649                 default:
 650                         return &nft_hash_ops;
 651                 }
 652         }
 653
 654         return &nft_rhash_ops;
 655 }
 656
 657 static struct nft_set_type nft_hash_type __read_mostly = {
 658         .select_ops     = nft_hash_select_ops,
 659         .owner          = THIS_MODULE,
 660 };
 661
 662 static int __init nft_hash_module_init(void)
 663 {
 664         return nft_register_set(&nft_hash_type);
 665 }
 666
 667 static void __exit nft_hash_module_exit(void)
 668 {
 669         nft_unregister_set(&nft_hash_type);
 670 }
 671
 672 module_init(nft_hash_module_init);
 673 module_exit(nft_hash_module_exit);
 674
 675 MODULE_LICENSE("GPL");
 676 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 677 MODULE_ALIAS_NFT_SET();