1 /* 2 * xt_hashlimit - Netfilter module to limit the number of packets per time 3 * separately for each hashbucket (sourceip/sourceport/dstip/dstport) 4 * 5 * (C) 2003-2004 by Harald Welte <laforge@netfilter.org> 6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net> 7 * Copyright © CC Computer Consultants GmbH, 2007 - 2008 8 * 9 * Development of this code was funded by Astaro AG, http://www.astaro.com/ 10 */ 11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 12 #include <linux/module.h> 13 #include <linux/spinlock.h> 14 #include <linux/random.h> 15 #include <linux/jhash.h> 16 #include <linux/slab.h> 17 #include <linux/vmalloc.h> 18 #include <linux/proc_fs.h> 19 #include <linux/seq_file.h> 20 #include <linux/list.h> 21 #include <linux/skbuff.h> 22 #include <linux/mm.h> 23 #include <linux/in.h> 24 #include <linux/ip.h> 25 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 26 #include <linux/ipv6.h> 27 #include <net/ipv6.h> 28 #endif 29 30 #include <net/net_namespace.h> 31 #include <net/netns/generic.h> 32 33 #include <linux/netfilter/x_tables.h> 34 #include <linux/netfilter_ipv4/ip_tables.h> 35 #include <linux/netfilter_ipv6/ip6_tables.h> 36 #include <linux/netfilter/xt_hashlimit.h> 37 #include <linux/mutex.h> 38 #include <linux/kernel.h> 39 40 MODULE_LICENSE("GPL"); 41 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 42 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); 43 MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match"); 44 MODULE_ALIAS("ipt_hashlimit"); 45 MODULE_ALIAS("ip6t_hashlimit"); 46 47 struct hashlimit_net { 48 struct hlist_head htables; 49 struct proc_dir_entry *ipt_hashlimit; 50 struct proc_dir_entry *ip6t_hashlimit; 51 }; 52 53 static unsigned int hashlimit_net_id; 54 static inline struct hashlimit_net *hashlimit_pernet(struct net *net) 55 { 56 return net_generic(net, hashlimit_net_id); 57 } 58 59 /* need to declare this at the top */ 60 static const struct seq_operations dl_seq_ops_v2; 61 static const struct seq_operations dl_seq_ops_v1; 62 static const struct seq_operations dl_seq_ops; 63 64 /* hash table crap */ 65 struct dsthash_dst { 66 union { 67 struct { 68 __be32 src; 69 __be32 dst; 70 } ip; 71 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 72 struct { 73 __be32 src[4]; 74 __be32 dst[4]; 75 } ip6; 76 #endif 77 }; 78 __be16 src_port; 79 __be16 dst_port; 80 }; 81 82 struct dsthash_ent { 83 /* static / read-only parts in the beginning */ 84 struct hlist_node node; 85 struct dsthash_dst dst; 86 87 /* modified structure members in the end */ 88 spinlock_t lock; 89 unsigned long expires; /* precalculated expiry time */ 90 struct { 91 unsigned long prev; /* last modification */ 92 union { 93 struct { 94 u_int64_t credit; 95 u_int64_t credit_cap; 96 u_int64_t cost; 97 }; 98 struct { 99 u_int32_t interval, prev_window; 100 u_int64_t current_rate; 101 u_int64_t rate; 102 int64_t burst; 103 }; 104 }; 105 } rateinfo; 106 struct rcu_head rcu; 107 }; 108 109 struct xt_hashlimit_htable { 110 struct hlist_node node; /* global list of all htables */ 111 int use; 112 u_int8_t family; 113 bool rnd_initialized; 114 115 struct hashlimit_cfg3 cfg; /* config */ 116 117 /* used internally */ 118 spinlock_t lock; /* lock for list_head */ 119 u_int32_t rnd; /* random seed for hash */ 120 unsigned int count; /* number entries in table */ 121 struct delayed_work gc_work; 122 123 /* seq_file stuff */ 124 struct proc_dir_entry *pde; 125 const char *name; 126 struct net *net; 127 128 struct hlist_head hash[0]; /* hashtable itself */ 129 }; 130 131 static int 132 cfg_copy(struct hashlimit_cfg3 *to, const void *from, int revision) 133 { 134 if (revision == 1) { 135 struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from; 136 137 to->mode = cfg->mode; 138 to->avg = cfg->avg; 139 to->burst = cfg->burst; 140 to->size = cfg->size; 141 to->max = cfg->max; 142 to->gc_interval = cfg->gc_interval; 143 to->expire = cfg->expire; 144 to->srcmask = cfg->srcmask; 145 to->dstmask = cfg->dstmask; 146 } else if (revision == 2) { 147 struct hashlimit_cfg2 *cfg = (struct hashlimit_cfg2 *)from; 148 149 to->mode = cfg->mode; 150 to->avg = cfg->avg; 151 to->burst = cfg->burst; 152 to->size = cfg->size; 153 to->max = cfg->max; 154 to->gc_interval = cfg->gc_interval; 155 to->expire = cfg->expire; 156 to->srcmask = cfg->srcmask; 157 to->dstmask = cfg->dstmask; 158 } else if (revision == 3) { 159 memcpy(to, from, sizeof(struct hashlimit_cfg3)); 160 } else { 161 return -EINVAL; 162 } 163 164 return 0; 165 } 166 167 static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */ 168 static struct kmem_cache *hashlimit_cachep __read_mostly; 169 170 static inline bool dst_cmp(const struct dsthash_ent *ent, 171 const struct dsthash_dst *b) 172 { 173 return !memcmp(&ent->dst, b, sizeof(ent->dst)); 174 } 175 176 static u_int32_t 177 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst) 178 { 179 u_int32_t hash = jhash2((const u32 *)dst, 180 sizeof(*dst)/sizeof(u32), 181 ht->rnd); 182 /* 183 * Instead of returning hash % ht->cfg.size (implying a divide) 184 * we return the high 32 bits of the (hash * ht->cfg.size) that will 185 * give results between [0 and cfg.size-1] and same hash distribution, 186 * but using a multiply, less expensive than a divide 187 */ 188 return reciprocal_scale(hash, ht->cfg.size); 189 } 190 191 static struct dsthash_ent * 192 dsthash_find(const struct xt_hashlimit_htable *ht, 193 const struct dsthash_dst *dst) 194 { 195 struct dsthash_ent *ent; 196 u_int32_t hash = hash_dst(ht, dst); 197 198 if (!hlist_empty(&ht->hash[hash])) { 199 hlist_for_each_entry_rcu(ent, &ht->hash[hash], node) 200 if (dst_cmp(ent, dst)) { 201 spin_lock(&ent->lock); 202 return ent; 203 } 204 } 205 return NULL; 206 } 207 208 /* allocate dsthash_ent, initialize dst, put in htable and lock it */ 209 static struct dsthash_ent * 210 dsthash_alloc_init(struct xt_hashlimit_htable *ht, 211 const struct dsthash_dst *dst, bool *race) 212 { 213 struct dsthash_ent *ent; 214 215 spin_lock(&ht->lock); 216 217 /* Two or more packets may race to create the same entry in the 218 * hashtable, double check if this packet lost race. 219 */ 220 ent = dsthash_find(ht, dst); 221 if (ent != NULL) { 222 spin_unlock(&ht->lock); 223 *race = true; 224 return ent; 225 } 226 227 /* initialize hash with random val at the time we allocate 228 * the first hashtable entry */ 229 if (unlikely(!ht->rnd_initialized)) { 230 get_random_bytes(&ht->rnd, sizeof(ht->rnd)); 231 ht->rnd_initialized = true; 232 } 233 234 if (ht->cfg.max && ht->count >= ht->cfg.max) { 235 /* FIXME: do something. question is what.. */ 236 net_err_ratelimited("max count of %u reached\n", ht->cfg.max); 237 ent = NULL; 238 } else 239 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC); 240 if (ent) { 241 memcpy(&ent->dst, dst, sizeof(ent->dst)); 242 spin_lock_init(&ent->lock); 243 244 spin_lock(&ent->lock); 245 hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]); 246 ht->count++; 247 } 248 spin_unlock(&ht->lock); 249 return ent; 250 } 251 252 static void dsthash_free_rcu(struct rcu_head *head) 253 { 254 struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu); 255 256 kmem_cache_free(hashlimit_cachep, ent); 257 } 258 259 static inline void 260 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent) 261 { 262 hlist_del_rcu(&ent->node); 263 call_rcu(&ent->rcu, dsthash_free_rcu); 264 ht->count--; 265 } 266 static void htable_gc(struct work_struct *work); 267 268 static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg, 269 const char *name, u_int8_t family, 270 struct xt_hashlimit_htable **out_hinfo, 271 int revision) 272 { 273 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 274 struct xt_hashlimit_htable *hinfo; 275 const struct seq_operations *ops; 276 unsigned int size, i; 277 unsigned long nr_pages = totalram_pages(); 278 int ret; 279 280 if (cfg->size) { 281 size = cfg->size; 282 } else { 283 size = (nr_pages << PAGE_SHIFT) / 16384 / 284 sizeof(struct hlist_head); 285 if (nr_pages > 1024 * 1024 * 1024 / PAGE_SIZE) 286 size = 8192; 287 if (size < 16) 288 size = 16; 289 } 290 /* FIXME: don't use vmalloc() here or anywhere else -HW */ 291 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) + 292 sizeof(struct hlist_head) * size); 293 if (hinfo == NULL) 294 return -ENOMEM; 295 *out_hinfo = hinfo; 296 297 /* copy match config into hashtable config */ 298 ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3); 299 if (ret) { 300 vfree(hinfo); 301 return ret; 302 } 303 304 hinfo->cfg.size = size; 305 if (hinfo->cfg.max == 0) 306 hinfo->cfg.max = 8 * hinfo->cfg.size; 307 else if (hinfo->cfg.max < hinfo->cfg.size) 308 hinfo->cfg.max = hinfo->cfg.size; 309 310 for (i = 0; i < hinfo->cfg.size; i++) 311 INIT_HLIST_HEAD(&hinfo->hash[i]); 312 313 hinfo->use = 1; 314 hinfo->count = 0; 315 hinfo->family = family; 316 hinfo->rnd_initialized = false; 317 hinfo->name = kstrdup(name, GFP_KERNEL); 318 if (!hinfo->name) { 319 vfree(hinfo); 320 return -ENOMEM; 321 } 322 spin_lock_init(&hinfo->lock); 323 324 switch (revision) { 325 case 1: 326 ops = &dl_seq_ops_v1; 327 break; 328 case 2: 329 ops = &dl_seq_ops_v2; 330 break; 331 default: 332 ops = &dl_seq_ops; 333 } 334 335 hinfo->pde = proc_create_seq_data(name, 0, 336 (family == NFPROTO_IPV4) ? 337 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit, 338 ops, hinfo); 339 if (hinfo->pde == NULL) { 340 kfree(hinfo->name); 341 vfree(hinfo); 342 return -ENOMEM; 343 } 344 hinfo->net = net; 345 346 INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc); 347 queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work, 348 msecs_to_jiffies(hinfo->cfg.gc_interval)); 349 350 hlist_add_head(&hinfo->node, &hashlimit_net->htables); 351 352 return 0; 353 } 354 355 static bool select_all(const struct xt_hashlimit_htable *ht, 356 const struct dsthash_ent *he) 357 { 358 return true; 359 } 360 361 static bool select_gc(const struct xt_hashlimit_htable *ht, 362 const struct dsthash_ent *he) 363 { 364 return time_after_eq(jiffies, he->expires); 365 } 366 367 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, 368 bool (*select)(const struct xt_hashlimit_htable *ht, 369 const struct dsthash_ent *he)) 370 { 371 unsigned int i; 372 373 for (i = 0; i < ht->cfg.size; i++) { 374 struct dsthash_ent *dh; 375 struct hlist_node *n; 376 377 spin_lock_bh(&ht->lock); 378 hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) { 379 if ((*select)(ht, dh)) 380 dsthash_free(ht, dh); 381 } 382 spin_unlock_bh(&ht->lock); 383 cond_resched(); 384 } 385 } 386 387 static void htable_gc(struct work_struct *work) 388 { 389 struct xt_hashlimit_htable *ht; 390 391 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work); 392 393 htable_selective_cleanup(ht, select_gc); 394 395 queue_delayed_work(system_power_efficient_wq, 396 &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval)); 397 } 398 399 static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo) 400 { 401 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net); 402 struct proc_dir_entry *parent; 403 404 if (hinfo->family == NFPROTO_IPV4) 405 parent = hashlimit_net->ipt_hashlimit; 406 else 407 parent = hashlimit_net->ip6t_hashlimit; 408 409 if (parent != NULL) 410 remove_proc_entry(hinfo->name, parent); 411 } 412 413 static void htable_destroy(struct xt_hashlimit_htable *hinfo) 414 { 415 cancel_delayed_work_sync(&hinfo->gc_work); 416 htable_remove_proc_entry(hinfo); 417 htable_selective_cleanup(hinfo, select_all); 418 kfree(hinfo->name); 419 vfree(hinfo); 420 } 421 422 static struct xt_hashlimit_htable *htable_find_get(struct net *net, 423 const char *name, 424 u_int8_t family) 425 { 426 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 427 struct xt_hashlimit_htable *hinfo; 428 429 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) { 430 if (!strcmp(name, hinfo->name) && 431 hinfo->family == family) { 432 hinfo->use++; 433 return hinfo; 434 } 435 } 436 return NULL; 437 } 438 439 static void htable_put(struct xt_hashlimit_htable *hinfo) 440 { 441 mutex_lock(&hashlimit_mutex); 442 if (--hinfo->use == 0) { 443 hlist_del(&hinfo->node); 444 htable_destroy(hinfo); 445 } 446 mutex_unlock(&hashlimit_mutex); 447 } 448 449 /* The algorithm used is the Simple Token Bucket Filter (TBF) 450 * see net/sched/sch_tbf.c in the linux source tree 451 */ 452 453 /* Rusty: This is my (non-mathematically-inclined) understanding of 454 this algorithm. The `average rate' in jiffies becomes your initial 455 amount of credit `credit' and the most credit you can ever have 456 `credit_cap'. The `peak rate' becomes the cost of passing the 457 test, `cost'. 458 459 `prev' tracks the last packet hit: you gain one credit per jiffy. 460 If you get credit balance more than this, the extra credit is 461 discarded. Every time the match passes, you lose `cost' credits; 462 if you don't have that many, the test fails. 463 464 See Alexey's formal explanation in net/sched/sch_tbf.c. 465 466 To get the maximum range, we multiply by this factor (ie. you get N 467 credits per jiffy). We want to allow a rate as low as 1 per day 468 (slowest userspace tool allows), which means 469 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie. 470 */ 471 #define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24)) 472 #define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24)) 473 474 /* Repeated shift and or gives us all 1s, final shift and add 1 gives 475 * us the power of 2 below the theoretical max, so GCC simply does a 476 * shift. */ 477 #define _POW2_BELOW2(x) ((x)|((x)>>1)) 478 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2)) 479 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4)) 480 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8)) 481 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16)) 482 #define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32)) 483 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1) 484 #define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1) 485 486 #define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ) 487 #define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1) 488 489 /* in byte mode, the lowest possible rate is one packet/second. 490 * credit_cap is used as a counter that tells us how many times we can 491 * refill the "credits available" counter when it becomes empty. 492 */ 493 #define MAX_CPJ_BYTES (0xFFFFFFFF / HZ) 494 #define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES) 495 496 static u32 xt_hashlimit_len_to_chunks(u32 len) 497 { 498 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1; 499 } 500 501 /* Precision saver. */ 502 static u64 user2credits(u64 user, int revision) 503 { 504 u64 scale = (revision == 1) ? 505 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2; 506 u64 cpj = (revision == 1) ? 507 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY; 508 509 /* Avoid overflow: divide the constant operands first */ 510 if (scale >= HZ * cpj) 511 return div64_u64(user, div64_u64(scale, HZ * cpj)); 512 513 return user * div64_u64(HZ * cpj, scale); 514 } 515 516 static u32 user2credits_byte(u32 user) 517 { 518 u64 us = user; 519 us *= HZ * CREDITS_PER_JIFFY_BYTES; 520 return (u32) (us >> 32); 521 } 522 523 static u64 user2rate(u64 user) 524 { 525 if (user != 0) { 526 return div64_u64(XT_HASHLIMIT_SCALE_v2, user); 527 } else { 528 pr_info_ratelimited("invalid rate from userspace: %llu\n", 529 user); 530 return 0; 531 } 532 } 533 534 static u64 user2rate_bytes(u32 user) 535 { 536 u64 r; 537 538 r = user ? U32_MAX / user : U32_MAX; 539 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT; 540 } 541 542 static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now, 543 u32 mode, int revision) 544 { 545 unsigned long delta = now - dh->rateinfo.prev; 546 u64 cap, cpj; 547 548 if (delta == 0) 549 return; 550 551 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) { 552 u64 interval = dh->rateinfo.interval * HZ; 553 554 if (delta < interval) 555 return; 556 557 dh->rateinfo.prev = now; 558 dh->rateinfo.prev_window = 559 ((dh->rateinfo.current_rate * interval) > 560 (delta * dh->rateinfo.rate)); 561 dh->rateinfo.current_rate = 0; 562 563 return; 564 } 565 566 dh->rateinfo.prev = now; 567 568 if (mode & XT_HASHLIMIT_BYTES) { 569 u64 tmp = dh->rateinfo.credit; 570 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta; 571 cap = CREDITS_PER_JIFFY_BYTES * HZ; 572 if (tmp >= dh->rateinfo.credit) {/* overflow */ 573 dh->rateinfo.credit = cap; 574 return; 575 } 576 } else { 577 cpj = (revision == 1) ? 578 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY; 579 dh->rateinfo.credit += delta * cpj; 580 cap = dh->rateinfo.credit_cap; 581 } 582 if (dh->rateinfo.credit > cap) 583 dh->rateinfo.credit = cap; 584 } 585 586 static void rateinfo_init(struct dsthash_ent *dh, 587 struct xt_hashlimit_htable *hinfo, int revision) 588 { 589 dh->rateinfo.prev = jiffies; 590 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) { 591 dh->rateinfo.prev_window = 0; 592 dh->rateinfo.current_rate = 0; 593 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { 594 dh->rateinfo.rate = 595 user2rate_bytes((u32)hinfo->cfg.avg); 596 if (hinfo->cfg.burst) 597 dh->rateinfo.burst = 598 hinfo->cfg.burst * dh->rateinfo.rate; 599 else 600 dh->rateinfo.burst = dh->rateinfo.rate; 601 } else { 602 dh->rateinfo.rate = user2rate(hinfo->cfg.avg); 603 dh->rateinfo.burst = 604 hinfo->cfg.burst + dh->rateinfo.rate; 605 } 606 dh->rateinfo.interval = hinfo->cfg.interval; 607 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { 608 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ; 609 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg); 610 dh->rateinfo.credit_cap = hinfo->cfg.burst; 611 } else { 612 dh->rateinfo.credit = user2credits(hinfo->cfg.avg * 613 hinfo->cfg.burst, revision); 614 dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision); 615 dh->rateinfo.credit_cap = dh->rateinfo.credit; 616 } 617 } 618 619 static inline __be32 maskl(__be32 a, unsigned int l) 620 { 621 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0; 622 } 623 624 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 625 static void hashlimit_ipv6_mask(__be32 *i, unsigned int p) 626 { 627 switch (p) { 628 case 0 ... 31: 629 i[0] = maskl(i[0], p); 630 i[1] = i[2] = i[3] = 0; 631 break; 632 case 32 ... 63: 633 i[1] = maskl(i[1], p - 32); 634 i[2] = i[3] = 0; 635 break; 636 case 64 ... 95: 637 i[2] = maskl(i[2], p - 64); 638 i[3] = 0; 639 break; 640 case 96 ... 127: 641 i[3] = maskl(i[3], p - 96); 642 break; 643 case 128: 644 break; 645 } 646 } 647 #endif 648 649 static int 650 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo, 651 struct dsthash_dst *dst, 652 const struct sk_buff *skb, unsigned int protoff) 653 { 654 __be16 _ports[2], *ports; 655 u8 nexthdr; 656 int poff; 657 658 memset(dst, 0, sizeof(*dst)); 659 660 switch (hinfo->family) { 661 case NFPROTO_IPV4: 662 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) 663 dst->ip.dst = maskl(ip_hdr(skb)->daddr, 664 hinfo->cfg.dstmask); 665 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) 666 dst->ip.src = maskl(ip_hdr(skb)->saddr, 667 hinfo->cfg.srcmask); 668 669 if (!(hinfo->cfg.mode & 670 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT))) 671 return 0; 672 nexthdr = ip_hdr(skb)->protocol; 673 break; 674 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 675 case NFPROTO_IPV6: 676 { 677 __be16 frag_off; 678 679 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) { 680 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr, 681 sizeof(dst->ip6.dst)); 682 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask); 683 } 684 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) { 685 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr, 686 sizeof(dst->ip6.src)); 687 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask); 688 } 689 690 if (!(hinfo->cfg.mode & 691 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT))) 692 return 0; 693 nexthdr = ipv6_hdr(skb)->nexthdr; 694 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); 695 if ((int)protoff < 0) 696 return -1; 697 break; 698 } 699 #endif 700 default: 701 BUG(); 702 return 0; 703 } 704 705 poff = proto_ports_offset(nexthdr); 706 if (poff >= 0) { 707 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports), 708 &_ports); 709 } else { 710 _ports[0] = _ports[1] = 0; 711 ports = _ports; 712 } 713 if (!ports) 714 return -1; 715 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT) 716 dst->src_port = ports[0]; 717 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT) 718 dst->dst_port = ports[1]; 719 return 0; 720 } 721 722 static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh) 723 { 724 u64 tmp = xt_hashlimit_len_to_chunks(len); 725 tmp = tmp * dh->rateinfo.cost; 726 727 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ)) 728 tmp = CREDITS_PER_JIFFY_BYTES * HZ; 729 730 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) { 731 dh->rateinfo.credit_cap--; 732 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ; 733 } 734 return (u32) tmp; 735 } 736 737 static bool 738 hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par, 739 struct xt_hashlimit_htable *hinfo, 740 const struct hashlimit_cfg3 *cfg, int revision) 741 { 742 unsigned long now = jiffies; 743 struct dsthash_ent *dh; 744 struct dsthash_dst dst; 745 bool race = false; 746 u64 cost; 747 748 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0) 749 goto hotdrop; 750 751 local_bh_disable(); 752 dh = dsthash_find(hinfo, &dst); 753 if (dh == NULL) { 754 dh = dsthash_alloc_init(hinfo, &dst, &race); 755 if (dh == NULL) { 756 local_bh_enable(); 757 goto hotdrop; 758 } else if (race) { 759 /* Already got an entry, update expiration timeout */ 760 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); 761 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision); 762 } else { 763 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); 764 rateinfo_init(dh, hinfo, revision); 765 } 766 } else { 767 /* update expiration timeout */ 768 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); 769 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision); 770 } 771 772 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) { 773 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1; 774 dh->rateinfo.current_rate += cost; 775 776 if (!dh->rateinfo.prev_window && 777 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) { 778 spin_unlock(&dh->lock); 779 local_bh_enable(); 780 return !(cfg->mode & XT_HASHLIMIT_INVERT); 781 } else { 782 goto overlimit; 783 } 784 } 785 786 if (cfg->mode & XT_HASHLIMIT_BYTES) 787 cost = hashlimit_byte_cost(skb->len, dh); 788 else 789 cost = dh->rateinfo.cost; 790 791 if (dh->rateinfo.credit >= cost) { 792 /* below the limit */ 793 dh->rateinfo.credit -= cost; 794 spin_unlock(&dh->lock); 795 local_bh_enable(); 796 return !(cfg->mode & XT_HASHLIMIT_INVERT); 797 } 798 799 overlimit: 800 spin_unlock(&dh->lock); 801 local_bh_enable(); 802 /* default match is underlimit - so over the limit, we need to invert */ 803 return cfg->mode & XT_HASHLIMIT_INVERT; 804 805 hotdrop: 806 par->hotdrop = true; 807 return false; 808 } 809 810 static bool 811 hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) 812 { 813 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 814 struct xt_hashlimit_htable *hinfo = info->hinfo; 815 struct hashlimit_cfg3 cfg = {}; 816 int ret; 817 818 ret = cfg_copy(&cfg, (void *)&info->cfg, 1); 819 if (ret) 820 return ret; 821 822 return hashlimit_mt_common(skb, par, hinfo, &cfg, 1); 823 } 824 825 static bool 826 hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par) 827 { 828 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 829 struct xt_hashlimit_htable *hinfo = info->hinfo; 830 struct hashlimit_cfg3 cfg = {}; 831 int ret; 832 833 ret = cfg_copy(&cfg, (void *)&info->cfg, 2); 834 if (ret) 835 return ret; 836 837 return hashlimit_mt_common(skb, par, hinfo, &cfg, 2); 838 } 839 840 static bool 841 hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) 842 { 843 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 844 struct xt_hashlimit_htable *hinfo = info->hinfo; 845 846 return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3); 847 } 848 849 static int hashlimit_mt_check_common(const struct xt_mtchk_param *par, 850 struct xt_hashlimit_htable **hinfo, 851 struct hashlimit_cfg3 *cfg, 852 const char *name, int revision) 853 { 854 struct net *net = par->net; 855 int ret; 856 857 if (cfg->gc_interval == 0 || cfg->expire == 0) 858 return -EINVAL; 859 if (par->family == NFPROTO_IPV4) { 860 if (cfg->srcmask > 32 || cfg->dstmask > 32) 861 return -EINVAL; 862 } else { 863 if (cfg->srcmask > 128 || cfg->dstmask > 128) 864 return -EINVAL; 865 } 866 867 if (cfg->mode & ~XT_HASHLIMIT_ALL) { 868 pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n", 869 cfg->mode); 870 return -EINVAL; 871 } 872 873 /* Check for overflow. */ 874 if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) { 875 if (cfg->avg == 0 || cfg->avg > U32_MAX) { 876 pr_info_ratelimited("invalid rate\n"); 877 return -ERANGE; 878 } 879 880 if (cfg->interval == 0) { 881 pr_info_ratelimited("invalid interval\n"); 882 return -EINVAL; 883 } 884 } else if (cfg->mode & XT_HASHLIMIT_BYTES) { 885 if (user2credits_byte(cfg->avg) == 0) { 886 pr_info_ratelimited("overflow, rate too high: %llu\n", 887 cfg->avg); 888 return -EINVAL; 889 } 890 } else if (cfg->burst == 0 || 891 user2credits(cfg->avg * cfg->burst, revision) < 892 user2credits(cfg->avg, revision)) { 893 pr_info_ratelimited("overflow, try lower: %llu/%llu\n", 894 cfg->avg, cfg->burst); 895 return -ERANGE; 896 } 897 898 mutex_lock(&hashlimit_mutex); 899 *hinfo = htable_find_get(net, name, par->family); 900 if (*hinfo == NULL) { 901 ret = htable_create(net, cfg, name, par->family, 902 hinfo, revision); 903 if (ret < 0) { 904 mutex_unlock(&hashlimit_mutex); 905 return ret; 906 } 907 } 908 mutex_unlock(&hashlimit_mutex); 909 910 return 0; 911 } 912 913 static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par) 914 { 915 struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 916 struct hashlimit_cfg3 cfg = {}; 917 int ret; 918 919 ret = xt_check_proc_name(info->name, sizeof(info->name)); 920 if (ret) 921 return ret; 922 923 ret = cfg_copy(&cfg, (void *)&info->cfg, 1); 924 if (ret) 925 return ret; 926 927 return hashlimit_mt_check_common(par, &info->hinfo, 928 &cfg, info->name, 1); 929 } 930 931 static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par) 932 { 933 struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 934 struct hashlimit_cfg3 cfg = {}; 935 int ret; 936 937 ret = xt_check_proc_name(info->name, sizeof(info->name)); 938 if (ret) 939 return ret; 940 941 ret = cfg_copy(&cfg, (void *)&info->cfg, 2); 942 if (ret) 943 return ret; 944 945 return hashlimit_mt_check_common(par, &info->hinfo, 946 &cfg, info->name, 2); 947 } 948 949 static int hashlimit_mt_check(const struct xt_mtchk_param *par) 950 { 951 struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 952 int ret; 953 954 ret = xt_check_proc_name(info->name, sizeof(info->name)); 955 if (ret) 956 return ret; 957 958 return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg, 959 info->name, 3); 960 } 961 962 static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par) 963 { 964 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 965 966 htable_put(info->hinfo); 967 } 968 969 static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par) 970 { 971 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 972 973 htable_put(info->hinfo); 974 } 975 976 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par) 977 { 978 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 979 980 htable_put(info->hinfo); 981 } 982 983 static struct xt_match hashlimit_mt_reg[] __read_mostly = { 984 { 985 .name = "hashlimit", 986 .revision = 1, 987 .family = NFPROTO_IPV4, 988 .match = hashlimit_mt_v1, 989 .matchsize = sizeof(struct xt_hashlimit_mtinfo1), 990 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo), 991 .checkentry = hashlimit_mt_check_v1, 992 .destroy = hashlimit_mt_destroy_v1, 993 .me = THIS_MODULE, 994 }, 995 { 996 .name = "hashlimit", 997 .revision = 2, 998 .family = NFPROTO_IPV4, 999 .match = hashlimit_mt_v2, 1000 .matchsize = sizeof(struct xt_hashlimit_mtinfo2), 1001 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo), 1002 .checkentry = hashlimit_mt_check_v2, 1003 .destroy = hashlimit_mt_destroy_v2, 1004 .me = THIS_MODULE, 1005 }, 1006 { 1007 .name = "hashlimit", 1008 .revision = 3, 1009 .family = NFPROTO_IPV4, 1010 .match = hashlimit_mt, 1011 .matchsize = sizeof(struct xt_hashlimit_mtinfo3), 1012 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo), 1013 .checkentry = hashlimit_mt_check, 1014 .destroy = hashlimit_mt_destroy, 1015 .me = THIS_MODULE, 1016 }, 1017 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1018 { 1019 .name = "hashlimit", 1020 .revision = 1, 1021 .family = NFPROTO_IPV6, 1022 .match = hashlimit_mt_v1, 1023 .matchsize = sizeof(struct xt_hashlimit_mtinfo1), 1024 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo), 1025 .checkentry = hashlimit_mt_check_v1, 1026 .destroy = hashlimit_mt_destroy_v1, 1027 .me = THIS_MODULE, 1028 }, 1029 { 1030 .name = "hashlimit", 1031 .revision = 2, 1032 .family = NFPROTO_IPV6, 1033 .match = hashlimit_mt_v2, 1034 .matchsize = sizeof(struct xt_hashlimit_mtinfo2), 1035 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo), 1036 .checkentry = hashlimit_mt_check_v2, 1037 .destroy = hashlimit_mt_destroy_v2, 1038 .me = THIS_MODULE, 1039 }, 1040 { 1041 .name = "hashlimit", 1042 .revision = 3, 1043 .family = NFPROTO_IPV6, 1044 .match = hashlimit_mt, 1045 .matchsize = sizeof(struct xt_hashlimit_mtinfo3), 1046 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo), 1047 .checkentry = hashlimit_mt_check, 1048 .destroy = hashlimit_mt_destroy, 1049 .me = THIS_MODULE, 1050 }, 1051 #endif 1052 }; 1053 1054 /* PROC stuff */ 1055 static void *dl_seq_start(struct seq_file *s, loff_t *pos) 1056 __acquires(htable->lock) 1057 { 1058 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file)); 1059 unsigned int *bucket; 1060 1061 spin_lock_bh(&htable->lock); 1062 if (*pos >= htable->cfg.size) 1063 return NULL; 1064 1065 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC); 1066 if (!bucket) 1067 return ERR_PTR(-ENOMEM); 1068 1069 *bucket = *pos; 1070 return bucket; 1071 } 1072 1073 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos) 1074 { 1075 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file)); 1076 unsigned int *bucket = v; 1077 1078 *pos = ++(*bucket); 1079 if (*pos >= htable->cfg.size) { 1080 kfree(v); 1081 return NULL; 1082 } 1083 return bucket; 1084 } 1085 1086 static void dl_seq_stop(struct seq_file *s, void *v) 1087 __releases(htable->lock) 1088 { 1089 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file)); 1090 unsigned int *bucket = v; 1091 1092 if (!IS_ERR(bucket)) 1093 kfree(bucket); 1094 spin_unlock_bh(&htable->lock); 1095 } 1096 1097 static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family, 1098 struct seq_file *s) 1099 { 1100 switch (family) { 1101 case NFPROTO_IPV4: 1102 seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n", 1103 (long)(ent->expires - jiffies)/HZ, 1104 &ent->dst.ip.src, 1105 ntohs(ent->dst.src_port), 1106 &ent->dst.ip.dst, 1107 ntohs(ent->dst.dst_port), 1108 ent->rateinfo.credit, ent->rateinfo.credit_cap, 1109 ent->rateinfo.cost); 1110 break; 1111 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1112 case NFPROTO_IPV6: 1113 seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n", 1114 (long)(ent->expires - jiffies)/HZ, 1115 &ent->dst.ip6.src, 1116 ntohs(ent->dst.src_port), 1117 &ent->dst.ip6.dst, 1118 ntohs(ent->dst.dst_port), 1119 ent->rateinfo.credit, ent->rateinfo.credit_cap, 1120 ent->rateinfo.cost); 1121 break; 1122 #endif 1123 default: 1124 BUG(); 1125 } 1126 } 1127 1128 static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family, 1129 struct seq_file *s) 1130 { 1131 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file)); 1132 1133 spin_lock(&ent->lock); 1134 /* recalculate to show accurate numbers */ 1135 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2); 1136 1137 dl_seq_print(ent, family, s); 1138 1139 spin_unlock(&ent->lock); 1140 return seq_has_overflowed(s); 1141 } 1142 1143 static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family, 1144 struct seq_file *s) 1145 { 1146 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file)); 1147 1148 spin_lock(&ent->lock); 1149 /* recalculate to show accurate numbers */ 1150 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1); 1151 1152 dl_seq_print(ent, family, s); 1153 1154 spin_unlock(&ent->lock); 1155 return seq_has_overflowed(s); 1156 } 1157 1158 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family, 1159 struct seq_file *s) 1160 { 1161 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file)); 1162 1163 spin_lock(&ent->lock); 1164 /* recalculate to show accurate numbers */ 1165 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3); 1166 1167 dl_seq_print(ent, family, s); 1168 1169 spin_unlock(&ent->lock); 1170 return seq_has_overflowed(s); 1171 } 1172 1173 static int dl_seq_show_v2(struct seq_file *s, void *v) 1174 { 1175 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file)); 1176 unsigned int *bucket = (unsigned int *)v; 1177 struct dsthash_ent *ent; 1178 1179 if (!hlist_empty(&htable->hash[*bucket])) { 1180 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1181 if (dl_seq_real_show_v2(ent, htable->family, s)) 1182 return -1; 1183 } 1184 return 0; 1185 } 1186 1187 static int dl_seq_show_v1(struct seq_file *s, void *v) 1188 { 1189 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file)); 1190 unsigned int *bucket = v; 1191 struct dsthash_ent *ent; 1192 1193 if (!hlist_empty(&htable->hash[*bucket])) { 1194 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1195 if (dl_seq_real_show_v1(ent, htable->family, s)) 1196 return -1; 1197 } 1198 return 0; 1199 } 1200 1201 static int dl_seq_show(struct seq_file *s, void *v) 1202 { 1203 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file)); 1204 unsigned int *bucket = v; 1205 struct dsthash_ent *ent; 1206 1207 if (!hlist_empty(&htable->hash[*bucket])) { 1208 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1209 if (dl_seq_real_show(ent, htable->family, s)) 1210 return -1; 1211 } 1212 return 0; 1213 } 1214 1215 static const struct seq_operations dl_seq_ops_v1 = { 1216 .start = dl_seq_start, 1217 .next = dl_seq_next, 1218 .stop = dl_seq_stop, 1219 .show = dl_seq_show_v1 1220 }; 1221 1222 static const struct seq_operations dl_seq_ops_v2 = { 1223 .start = dl_seq_start, 1224 .next = dl_seq_next, 1225 .stop = dl_seq_stop, 1226 .show = dl_seq_show_v2 1227 }; 1228 1229 static const struct seq_operations dl_seq_ops = { 1230 .start = dl_seq_start, 1231 .next = dl_seq_next, 1232 .stop = dl_seq_stop, 1233 .show = dl_seq_show 1234 }; 1235 1236 static int __net_init hashlimit_proc_net_init(struct net *net) 1237 { 1238 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1239 1240 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net); 1241 if (!hashlimit_net->ipt_hashlimit) 1242 return -ENOMEM; 1243 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1244 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net); 1245 if (!hashlimit_net->ip6t_hashlimit) { 1246 remove_proc_entry("ipt_hashlimit", net->proc_net); 1247 return -ENOMEM; 1248 } 1249 #endif 1250 return 0; 1251 } 1252 1253 static void __net_exit hashlimit_proc_net_exit(struct net *net) 1254 { 1255 struct xt_hashlimit_htable *hinfo; 1256 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1257 1258 /* hashlimit_net_exit() is called before hashlimit_mt_destroy(). 1259 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc 1260 * entries is empty before trying to remove it. 1261 */ 1262 mutex_lock(&hashlimit_mutex); 1263 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) 1264 htable_remove_proc_entry(hinfo); 1265 hashlimit_net->ipt_hashlimit = NULL; 1266 hashlimit_net->ip6t_hashlimit = NULL; 1267 mutex_unlock(&hashlimit_mutex); 1268 1269 remove_proc_entry("ipt_hashlimit", net->proc_net); 1270 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1271 remove_proc_entry("ip6t_hashlimit", net->proc_net); 1272 #endif 1273 } 1274 1275 static int __net_init hashlimit_net_init(struct net *net) 1276 { 1277 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1278 1279 INIT_HLIST_HEAD(&hashlimit_net->htables); 1280 return hashlimit_proc_net_init(net); 1281 } 1282 1283 static void __net_exit hashlimit_net_exit(struct net *net) 1284 { 1285 hashlimit_proc_net_exit(net); 1286 } 1287 1288 static struct pernet_operations hashlimit_net_ops = { 1289 .init = hashlimit_net_init, 1290 .exit = hashlimit_net_exit, 1291 .id = &hashlimit_net_id, 1292 .size = sizeof(struct hashlimit_net), 1293 }; 1294 1295 static int __init hashlimit_mt_init(void) 1296 { 1297 int err; 1298 1299 err = register_pernet_subsys(&hashlimit_net_ops); 1300 if (err < 0) 1301 return err; 1302 err = xt_register_matches(hashlimit_mt_reg, 1303 ARRAY_SIZE(hashlimit_mt_reg)); 1304 if (err < 0) 1305 goto err1; 1306 1307 err = -ENOMEM; 1308 hashlimit_cachep = kmem_cache_create("xt_hashlimit", 1309 sizeof(struct dsthash_ent), 0, 0, 1310 NULL); 1311 if (!hashlimit_cachep) { 1312 pr_warn("unable to create slab cache\n"); 1313 goto err2; 1314 } 1315 return 0; 1316 1317 err2: 1318 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); 1319 err1: 1320 unregister_pernet_subsys(&hashlimit_net_ops); 1321 return err; 1322 1323 } 1324 1325 static void __exit hashlimit_mt_exit(void) 1326 { 1327 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); 1328 unregister_pernet_subsys(&hashlimit_net_ops); 1329 1330 rcu_barrier(); 1331 kmem_cache_destroy(hashlimit_cachep); 1332 } 1333 1334 module_init(hashlimit_mt_init); 1335 module_exit(hashlimit_mt_exit); 1336