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_bh(&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 int ret; 278 279 if (cfg->size) { 280 size = cfg->size; 281 } else { 282 size = (totalram_pages << PAGE_SHIFT) / 16384 / 283 sizeof(struct hlist_head); 284 if (totalram_pages > 1024 * 1024 * 1024 / PAGE_SIZE) 285 size = 8192; 286 if (size < 16) 287 size = 16; 288 } 289 /* FIXME: don't use vmalloc() here or anywhere else -HW */ 290 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) + 291 sizeof(struct hlist_head) * size); 292 if (hinfo == NULL) 293 return -ENOMEM; 294 *out_hinfo = hinfo; 295 296 /* copy match config into hashtable config */ 297 ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3); 298 299 if (ret) 300 return ret; 301 302 hinfo->cfg.size = size; 303 if (hinfo->cfg.max == 0) 304 hinfo->cfg.max = 8 * hinfo->cfg.size; 305 else if (hinfo->cfg.max < hinfo->cfg.size) 306 hinfo->cfg.max = hinfo->cfg.size; 307 308 for (i = 0; i < hinfo->cfg.size; i++) 309 INIT_HLIST_HEAD(&hinfo->hash[i]); 310 311 hinfo->use = 1; 312 hinfo->count = 0; 313 hinfo->family = family; 314 hinfo->rnd_initialized = false; 315 hinfo->name = kstrdup(name, GFP_KERNEL); 316 if (!hinfo->name) { 317 vfree(hinfo); 318 return -ENOMEM; 319 } 320 spin_lock_init(&hinfo->lock); 321 322 switch (revision) { 323 case 1: 324 ops = &dl_seq_ops_v1; 325 break; 326 case 2: 327 ops = &dl_seq_ops_v2; 328 break; 329 default: 330 ops = &dl_seq_ops; 331 } 332 333 hinfo->pde = proc_create_seq_data(name, 0, 334 (family == NFPROTO_IPV4) ? 335 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit, 336 ops, hinfo); 337 if (hinfo->pde == NULL) { 338 kfree(hinfo->name); 339 vfree(hinfo); 340 return -ENOMEM; 341 } 342 hinfo->net = net; 343 344 INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc); 345 queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work, 346 msecs_to_jiffies(hinfo->cfg.gc_interval)); 347 348 hlist_add_head(&hinfo->node, &hashlimit_net->htables); 349 350 return 0; 351 } 352 353 static bool select_all(const struct xt_hashlimit_htable *ht, 354 const struct dsthash_ent *he) 355 { 356 return true; 357 } 358 359 static bool select_gc(const struct xt_hashlimit_htable *ht, 360 const struct dsthash_ent *he) 361 { 362 return time_after_eq(jiffies, he->expires); 363 } 364 365 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, 366 bool (*select)(const struct xt_hashlimit_htable *ht, 367 const struct dsthash_ent *he)) 368 { 369 unsigned int i; 370 371 for (i = 0; i < ht->cfg.size; i++) { 372 struct dsthash_ent *dh; 373 struct hlist_node *n; 374 375 spin_lock_bh(&ht->lock); 376 hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) { 377 if ((*select)(ht, dh)) 378 dsthash_free(ht, dh); 379 } 380 spin_unlock_bh(&ht->lock); 381 cond_resched(); 382 } 383 } 384 385 static void htable_gc(struct work_struct *work) 386 { 387 struct xt_hashlimit_htable *ht; 388 389 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work); 390 391 htable_selective_cleanup(ht, select_gc); 392 393 queue_delayed_work(system_power_efficient_wq, 394 &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval)); 395 } 396 397 static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo) 398 { 399 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net); 400 struct proc_dir_entry *parent; 401 402 if (hinfo->family == NFPROTO_IPV4) 403 parent = hashlimit_net->ipt_hashlimit; 404 else 405 parent = hashlimit_net->ip6t_hashlimit; 406 407 if (parent != NULL) 408 remove_proc_entry(hinfo->name, parent); 409 } 410 411 static void htable_destroy(struct xt_hashlimit_htable *hinfo) 412 { 413 cancel_delayed_work_sync(&hinfo->gc_work); 414 htable_remove_proc_entry(hinfo); 415 htable_selective_cleanup(hinfo, select_all); 416 kfree(hinfo->name); 417 vfree(hinfo); 418 } 419 420 static struct xt_hashlimit_htable *htable_find_get(struct net *net, 421 const char *name, 422 u_int8_t family) 423 { 424 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 425 struct xt_hashlimit_htable *hinfo; 426 427 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) { 428 if (!strcmp(name, hinfo->name) && 429 hinfo->family == family) { 430 hinfo->use++; 431 return hinfo; 432 } 433 } 434 return NULL; 435 } 436 437 static void htable_put(struct xt_hashlimit_htable *hinfo) 438 { 439 mutex_lock(&hashlimit_mutex); 440 if (--hinfo->use == 0) { 441 hlist_del(&hinfo->node); 442 htable_destroy(hinfo); 443 } 444 mutex_unlock(&hashlimit_mutex); 445 } 446 447 /* The algorithm used is the Simple Token Bucket Filter (TBF) 448 * see net/sched/sch_tbf.c in the linux source tree 449 */ 450 451 /* Rusty: This is my (non-mathematically-inclined) understanding of 452 this algorithm. The `average rate' in jiffies becomes your initial 453 amount of credit `credit' and the most credit you can ever have 454 `credit_cap'. The `peak rate' becomes the cost of passing the 455 test, `cost'. 456 457 `prev' tracks the last packet hit: you gain one credit per jiffy. 458 If you get credit balance more than this, the extra credit is 459 discarded. Every time the match passes, you lose `cost' credits; 460 if you don't have that many, the test fails. 461 462 See Alexey's formal explanation in net/sched/sch_tbf.c. 463 464 To get the maximum range, we multiply by this factor (ie. you get N 465 credits per jiffy). We want to allow a rate as low as 1 per day 466 (slowest userspace tool allows), which means 467 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie. 468 */ 469 #define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24)) 470 #define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24)) 471 472 /* Repeated shift and or gives us all 1s, final shift and add 1 gives 473 * us the power of 2 below the theoretical max, so GCC simply does a 474 * shift. */ 475 #define _POW2_BELOW2(x) ((x)|((x)>>1)) 476 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2)) 477 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4)) 478 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8)) 479 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16)) 480 #define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32)) 481 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1) 482 #define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1) 483 484 #define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ) 485 #define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1) 486 487 /* in byte mode, the lowest possible rate is one packet/second. 488 * credit_cap is used as a counter that tells us how many times we can 489 * refill the "credits available" counter when it becomes empty. 490 */ 491 #define MAX_CPJ_BYTES (0xFFFFFFFF / HZ) 492 #define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES) 493 494 static u32 xt_hashlimit_len_to_chunks(u32 len) 495 { 496 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1; 497 } 498 499 /* Precision saver. */ 500 static u64 user2credits(u64 user, int revision) 501 { 502 u64 scale = (revision == 1) ? 503 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2; 504 u64 cpj = (revision == 1) ? 505 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY; 506 507 /* Avoid overflow: divide the constant operands first */ 508 if (scale >= HZ * cpj) 509 return div64_u64(user, div64_u64(scale, HZ * cpj)); 510 511 return user * div64_u64(HZ * cpj, scale); 512 } 513 514 static u32 user2credits_byte(u32 user) 515 { 516 u64 us = user; 517 us *= HZ * CREDITS_PER_JIFFY_BYTES; 518 return (u32) (us >> 32); 519 } 520 521 static u64 user2rate(u64 user) 522 { 523 if (user != 0) { 524 return div64_u64(XT_HASHLIMIT_SCALE_v2, user); 525 } else { 526 pr_info_ratelimited("invalid rate from userspace: %llu\n", 527 user); 528 return 0; 529 } 530 } 531 532 static u64 user2rate_bytes(u32 user) 533 { 534 u64 r; 535 536 r = user ? U32_MAX / user : U32_MAX; 537 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT; 538 } 539 540 static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now, 541 u32 mode, int revision) 542 { 543 unsigned long delta = now - dh->rateinfo.prev; 544 u64 cap, cpj; 545 546 if (delta == 0) 547 return; 548 549 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) { 550 u64 interval = dh->rateinfo.interval * HZ; 551 552 if (delta < interval) 553 return; 554 555 dh->rateinfo.prev = now; 556 dh->rateinfo.prev_window = 557 ((dh->rateinfo.current_rate * interval) > 558 (delta * dh->rateinfo.rate)); 559 dh->rateinfo.current_rate = 0; 560 561 return; 562 } 563 564 dh->rateinfo.prev = now; 565 566 if (mode & XT_HASHLIMIT_BYTES) { 567 u64 tmp = dh->rateinfo.credit; 568 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta; 569 cap = CREDITS_PER_JIFFY_BYTES * HZ; 570 if (tmp >= dh->rateinfo.credit) {/* overflow */ 571 dh->rateinfo.credit = cap; 572 return; 573 } 574 } else { 575 cpj = (revision == 1) ? 576 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY; 577 dh->rateinfo.credit += delta * cpj; 578 cap = dh->rateinfo.credit_cap; 579 } 580 if (dh->rateinfo.credit > cap) 581 dh->rateinfo.credit = cap; 582 } 583 584 static void rateinfo_init(struct dsthash_ent *dh, 585 struct xt_hashlimit_htable *hinfo, int revision) 586 { 587 dh->rateinfo.prev = jiffies; 588 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) { 589 dh->rateinfo.prev_window = 0; 590 dh->rateinfo.current_rate = 0; 591 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { 592 dh->rateinfo.rate = 593 user2rate_bytes((u32)hinfo->cfg.avg); 594 if (hinfo->cfg.burst) 595 dh->rateinfo.burst = 596 hinfo->cfg.burst * dh->rateinfo.rate; 597 else 598 dh->rateinfo.burst = dh->rateinfo.rate; 599 } else { 600 dh->rateinfo.rate = user2rate(hinfo->cfg.avg); 601 dh->rateinfo.burst = 602 hinfo->cfg.burst + dh->rateinfo.rate; 603 } 604 dh->rateinfo.interval = hinfo->cfg.interval; 605 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { 606 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ; 607 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg); 608 dh->rateinfo.credit_cap = hinfo->cfg.burst; 609 } else { 610 dh->rateinfo.credit = user2credits(hinfo->cfg.avg * 611 hinfo->cfg.burst, revision); 612 dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision); 613 dh->rateinfo.credit_cap = dh->rateinfo.credit; 614 } 615 } 616 617 static inline __be32 maskl(__be32 a, unsigned int l) 618 { 619 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0; 620 } 621 622 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 623 static void hashlimit_ipv6_mask(__be32 *i, unsigned int p) 624 { 625 switch (p) { 626 case 0 ... 31: 627 i[0] = maskl(i[0], p); 628 i[1] = i[2] = i[3] = 0; 629 break; 630 case 32 ... 63: 631 i[1] = maskl(i[1], p - 32); 632 i[2] = i[3] = 0; 633 break; 634 case 64 ... 95: 635 i[2] = maskl(i[2], p - 64); 636 i[3] = 0; 637 break; 638 case 96 ... 127: 639 i[3] = maskl(i[3], p - 96); 640 break; 641 case 128: 642 break; 643 } 644 } 645 #endif 646 647 static int 648 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo, 649 struct dsthash_dst *dst, 650 const struct sk_buff *skb, unsigned int protoff) 651 { 652 __be16 _ports[2], *ports; 653 u8 nexthdr; 654 int poff; 655 656 memset(dst, 0, sizeof(*dst)); 657 658 switch (hinfo->family) { 659 case NFPROTO_IPV4: 660 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) 661 dst->ip.dst = maskl(ip_hdr(skb)->daddr, 662 hinfo->cfg.dstmask); 663 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) 664 dst->ip.src = maskl(ip_hdr(skb)->saddr, 665 hinfo->cfg.srcmask); 666 667 if (!(hinfo->cfg.mode & 668 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT))) 669 return 0; 670 nexthdr = ip_hdr(skb)->protocol; 671 break; 672 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 673 case NFPROTO_IPV6: 674 { 675 __be16 frag_off; 676 677 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) { 678 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr, 679 sizeof(dst->ip6.dst)); 680 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask); 681 } 682 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) { 683 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr, 684 sizeof(dst->ip6.src)); 685 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask); 686 } 687 688 if (!(hinfo->cfg.mode & 689 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT))) 690 return 0; 691 nexthdr = ipv6_hdr(skb)->nexthdr; 692 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); 693 if ((int)protoff < 0) 694 return -1; 695 break; 696 } 697 #endif 698 default: 699 BUG(); 700 return 0; 701 } 702 703 poff = proto_ports_offset(nexthdr); 704 if (poff >= 0) { 705 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports), 706 &_ports); 707 } else { 708 _ports[0] = _ports[1] = 0; 709 ports = _ports; 710 } 711 if (!ports) 712 return -1; 713 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT) 714 dst->src_port = ports[0]; 715 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT) 716 dst->dst_port = ports[1]; 717 return 0; 718 } 719 720 static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh) 721 { 722 u64 tmp = xt_hashlimit_len_to_chunks(len); 723 tmp = tmp * dh->rateinfo.cost; 724 725 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ)) 726 tmp = CREDITS_PER_JIFFY_BYTES * HZ; 727 728 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) { 729 dh->rateinfo.credit_cap--; 730 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ; 731 } 732 return (u32) tmp; 733 } 734 735 static bool 736 hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par, 737 struct xt_hashlimit_htable *hinfo, 738 const struct hashlimit_cfg3 *cfg, int revision) 739 { 740 unsigned long now = jiffies; 741 struct dsthash_ent *dh; 742 struct dsthash_dst dst; 743 bool race = false; 744 u64 cost; 745 746 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0) 747 goto hotdrop; 748 749 local_bh_disable(); 750 dh = dsthash_find(hinfo, &dst); 751 if (dh == NULL) { 752 dh = dsthash_alloc_init(hinfo, &dst, &race); 753 if (dh == NULL) { 754 local_bh_enable(); 755 goto hotdrop; 756 } else if (race) { 757 /* Already got an entry, update expiration timeout */ 758 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); 759 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision); 760 } else { 761 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); 762 rateinfo_init(dh, hinfo, revision); 763 } 764 } else { 765 /* update expiration timeout */ 766 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); 767 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision); 768 } 769 770 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) { 771 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1; 772 dh->rateinfo.current_rate += cost; 773 774 if (!dh->rateinfo.prev_window && 775 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) { 776 spin_unlock(&dh->lock); 777 local_bh_enable(); 778 return !(cfg->mode & XT_HASHLIMIT_INVERT); 779 } else { 780 goto overlimit; 781 } 782 } 783 784 if (cfg->mode & XT_HASHLIMIT_BYTES) 785 cost = hashlimit_byte_cost(skb->len, dh); 786 else 787 cost = dh->rateinfo.cost; 788 789 if (dh->rateinfo.credit >= cost) { 790 /* below the limit */ 791 dh->rateinfo.credit -= cost; 792 spin_unlock(&dh->lock); 793 local_bh_enable(); 794 return !(cfg->mode & XT_HASHLIMIT_INVERT); 795 } 796 797 overlimit: 798 spin_unlock(&dh->lock); 799 local_bh_enable(); 800 /* default match is underlimit - so over the limit, we need to invert */ 801 return cfg->mode & XT_HASHLIMIT_INVERT; 802 803 hotdrop: 804 par->hotdrop = true; 805 return false; 806 } 807 808 static bool 809 hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) 810 { 811 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 812 struct xt_hashlimit_htable *hinfo = info->hinfo; 813 struct hashlimit_cfg3 cfg = {}; 814 int ret; 815 816 ret = cfg_copy(&cfg, (void *)&info->cfg, 1); 817 818 if (ret) 819 return ret; 820 821 return hashlimit_mt_common(skb, par, hinfo, &cfg, 1); 822 } 823 824 static bool 825 hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par) 826 { 827 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 828 struct xt_hashlimit_htable *hinfo = info->hinfo; 829 struct hashlimit_cfg3 cfg = {}; 830 int ret; 831 832 ret = cfg_copy(&cfg, (void *)&info->cfg, 2); 833 834 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); 924 925 if (ret) 926 return ret; 927 928 return hashlimit_mt_check_common(par, &info->hinfo, 929 &cfg, info->name, 1); 930 } 931 932 static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par) 933 { 934 struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 935 struct hashlimit_cfg3 cfg = {}; 936 int ret; 937 938 ret = xt_check_proc_name(info->name, sizeof(info->name)); 939 if (ret) 940 return ret; 941 942 ret = cfg_copy(&cfg, (void *)&info->cfg, 2); 943 944 if (ret) 945 return ret; 946 947 return hashlimit_mt_check_common(par, &info->hinfo, 948 &cfg, info->name, 2); 949 } 950 951 static int hashlimit_mt_check(const struct xt_mtchk_param *par) 952 { 953 struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 954 int ret; 955 956 ret = xt_check_proc_name(info->name, sizeof(info->name)); 957 if (ret) 958 return ret; 959 960 return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg, 961 info->name, 3); 962 } 963 964 static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par) 965 { 966 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 967 968 htable_put(info->hinfo); 969 } 970 971 static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par) 972 { 973 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 974 975 htable_put(info->hinfo); 976 } 977 978 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par) 979 { 980 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 981 982 htable_put(info->hinfo); 983 } 984 985 static struct xt_match hashlimit_mt_reg[] __read_mostly = { 986 { 987 .name = "hashlimit", 988 .revision = 1, 989 .family = NFPROTO_IPV4, 990 .match = hashlimit_mt_v1, 991 .matchsize = sizeof(struct xt_hashlimit_mtinfo1), 992 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo), 993 .checkentry = hashlimit_mt_check_v1, 994 .destroy = hashlimit_mt_destroy_v1, 995 .me = THIS_MODULE, 996 }, 997 { 998 .name = "hashlimit", 999 .revision = 2, 1000 .family = NFPROTO_IPV4, 1001 .match = hashlimit_mt_v2, 1002 .matchsize = sizeof(struct xt_hashlimit_mtinfo2), 1003 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo), 1004 .checkentry = hashlimit_mt_check_v2, 1005 .destroy = hashlimit_mt_destroy_v2, 1006 .me = THIS_MODULE, 1007 }, 1008 { 1009 .name = "hashlimit", 1010 .revision = 3, 1011 .family = NFPROTO_IPV4, 1012 .match = hashlimit_mt, 1013 .matchsize = sizeof(struct xt_hashlimit_mtinfo3), 1014 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo), 1015 .checkentry = hashlimit_mt_check, 1016 .destroy = hashlimit_mt_destroy, 1017 .me = THIS_MODULE, 1018 }, 1019 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1020 { 1021 .name = "hashlimit", 1022 .revision = 1, 1023 .family = NFPROTO_IPV6, 1024 .match = hashlimit_mt_v1, 1025 .matchsize = sizeof(struct xt_hashlimit_mtinfo1), 1026 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo), 1027 .checkentry = hashlimit_mt_check_v1, 1028 .destroy = hashlimit_mt_destroy_v1, 1029 .me = THIS_MODULE, 1030 }, 1031 { 1032 .name = "hashlimit", 1033 .revision = 2, 1034 .family = NFPROTO_IPV6, 1035 .match = hashlimit_mt_v2, 1036 .matchsize = sizeof(struct xt_hashlimit_mtinfo2), 1037 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo), 1038 .checkentry = hashlimit_mt_check_v2, 1039 .destroy = hashlimit_mt_destroy_v2, 1040 .me = THIS_MODULE, 1041 }, 1042 { 1043 .name = "hashlimit", 1044 .revision = 3, 1045 .family = NFPROTO_IPV6, 1046 .match = hashlimit_mt, 1047 .matchsize = sizeof(struct xt_hashlimit_mtinfo3), 1048 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo), 1049 .checkentry = hashlimit_mt_check, 1050 .destroy = hashlimit_mt_destroy, 1051 .me = THIS_MODULE, 1052 }, 1053 #endif 1054 }; 1055 1056 /* PROC stuff */ 1057 static void *dl_seq_start(struct seq_file *s, loff_t *pos) 1058 __acquires(htable->lock) 1059 { 1060 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->private)); 1061 unsigned int *bucket; 1062 1063 spin_lock_bh(&htable->lock); 1064 if (*pos >= htable->cfg.size) 1065 return NULL; 1066 1067 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC); 1068 if (!bucket) 1069 return ERR_PTR(-ENOMEM); 1070 1071 *bucket = *pos; 1072 return bucket; 1073 } 1074 1075 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos) 1076 { 1077 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->private)); 1078 unsigned int *bucket = v; 1079 1080 *pos = ++(*bucket); 1081 if (*pos >= htable->cfg.size) { 1082 kfree(v); 1083 return NULL; 1084 } 1085 return bucket; 1086 } 1087 1088 static void dl_seq_stop(struct seq_file *s, void *v) 1089 __releases(htable->lock) 1090 { 1091 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->private)); 1092 unsigned int *bucket = v; 1093 1094 if (!IS_ERR(bucket)) 1095 kfree(bucket); 1096 spin_unlock_bh(&htable->lock); 1097 } 1098 1099 static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family, 1100 struct seq_file *s) 1101 { 1102 switch (family) { 1103 case NFPROTO_IPV4: 1104 seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n", 1105 (long)(ent->expires - jiffies)/HZ, 1106 &ent->dst.ip.src, 1107 ntohs(ent->dst.src_port), 1108 &ent->dst.ip.dst, 1109 ntohs(ent->dst.dst_port), 1110 ent->rateinfo.credit, ent->rateinfo.credit_cap, 1111 ent->rateinfo.cost); 1112 break; 1113 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1114 case NFPROTO_IPV6: 1115 seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n", 1116 (long)(ent->expires - jiffies)/HZ, 1117 &ent->dst.ip6.src, 1118 ntohs(ent->dst.src_port), 1119 &ent->dst.ip6.dst, 1120 ntohs(ent->dst.dst_port), 1121 ent->rateinfo.credit, ent->rateinfo.credit_cap, 1122 ent->rateinfo.cost); 1123 break; 1124 #endif 1125 default: 1126 BUG(); 1127 } 1128 } 1129 1130 static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family, 1131 struct seq_file *s) 1132 { 1133 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->private)); 1134 1135 spin_lock(&ent->lock); 1136 /* recalculate to show accurate numbers */ 1137 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2); 1138 1139 dl_seq_print(ent, family, s); 1140 1141 spin_unlock(&ent->lock); 1142 return seq_has_overflowed(s); 1143 } 1144 1145 static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family, 1146 struct seq_file *s) 1147 { 1148 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->private)); 1149 1150 spin_lock(&ent->lock); 1151 /* recalculate to show accurate numbers */ 1152 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1); 1153 1154 dl_seq_print(ent, family, s); 1155 1156 spin_unlock(&ent->lock); 1157 return seq_has_overflowed(s); 1158 } 1159 1160 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family, 1161 struct seq_file *s) 1162 { 1163 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->private)); 1164 1165 spin_lock(&ent->lock); 1166 /* recalculate to show accurate numbers */ 1167 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3); 1168 1169 dl_seq_print(ent, family, s); 1170 1171 spin_unlock(&ent->lock); 1172 return seq_has_overflowed(s); 1173 } 1174 1175 static int dl_seq_show_v2(struct seq_file *s, void *v) 1176 { 1177 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->private)); 1178 unsigned int *bucket = (unsigned int *)v; 1179 struct dsthash_ent *ent; 1180 1181 if (!hlist_empty(&htable->hash[*bucket])) { 1182 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1183 if (dl_seq_real_show_v2(ent, htable->family, s)) 1184 return -1; 1185 } 1186 return 0; 1187 } 1188 1189 static int dl_seq_show_v1(struct seq_file *s, void *v) 1190 { 1191 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->private)); 1192 unsigned int *bucket = v; 1193 struct dsthash_ent *ent; 1194 1195 if (!hlist_empty(&htable->hash[*bucket])) { 1196 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1197 if (dl_seq_real_show_v1(ent, htable->family, s)) 1198 return -1; 1199 } 1200 return 0; 1201 } 1202 1203 static int dl_seq_show(struct seq_file *s, void *v) 1204 { 1205 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->private)); 1206 unsigned int *bucket = v; 1207 struct dsthash_ent *ent; 1208 1209 if (!hlist_empty(&htable->hash[*bucket])) { 1210 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1211 if (dl_seq_real_show(ent, htable->family, s)) 1212 return -1; 1213 } 1214 return 0; 1215 } 1216 1217 static const struct seq_operations dl_seq_ops_v1 = { 1218 .start = dl_seq_start, 1219 .next = dl_seq_next, 1220 .stop = dl_seq_stop, 1221 .show = dl_seq_show_v1 1222 }; 1223 1224 static const struct seq_operations dl_seq_ops_v2 = { 1225 .start = dl_seq_start, 1226 .next = dl_seq_next, 1227 .stop = dl_seq_stop, 1228 .show = dl_seq_show_v2 1229 }; 1230 1231 static const struct seq_operations dl_seq_ops = { 1232 .start = dl_seq_start, 1233 .next = dl_seq_next, 1234 .stop = dl_seq_stop, 1235 .show = dl_seq_show 1236 }; 1237 1238 static int __net_init hashlimit_proc_net_init(struct net *net) 1239 { 1240 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1241 1242 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net); 1243 if (!hashlimit_net->ipt_hashlimit) 1244 return -ENOMEM; 1245 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1246 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net); 1247 if (!hashlimit_net->ip6t_hashlimit) { 1248 remove_proc_entry("ipt_hashlimit", net->proc_net); 1249 return -ENOMEM; 1250 } 1251 #endif 1252 return 0; 1253 } 1254 1255 static void __net_exit hashlimit_proc_net_exit(struct net *net) 1256 { 1257 struct xt_hashlimit_htable *hinfo; 1258 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1259 1260 /* hashlimit_net_exit() is called before hashlimit_mt_destroy(). 1261 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc 1262 * entries is empty before trying to remove it. 1263 */ 1264 mutex_lock(&hashlimit_mutex); 1265 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) 1266 htable_remove_proc_entry(hinfo); 1267 hashlimit_net->ipt_hashlimit = NULL; 1268 hashlimit_net->ip6t_hashlimit = NULL; 1269 mutex_unlock(&hashlimit_mutex); 1270 1271 remove_proc_entry("ipt_hashlimit", net->proc_net); 1272 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1273 remove_proc_entry("ip6t_hashlimit", net->proc_net); 1274 #endif 1275 } 1276 1277 static int __net_init hashlimit_net_init(struct net *net) 1278 { 1279 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1280 1281 INIT_HLIST_HEAD(&hashlimit_net->htables); 1282 return hashlimit_proc_net_init(net); 1283 } 1284 1285 static void __net_exit hashlimit_net_exit(struct net *net) 1286 { 1287 hashlimit_proc_net_exit(net); 1288 } 1289 1290 static struct pernet_operations hashlimit_net_ops = { 1291 .init = hashlimit_net_init, 1292 .exit = hashlimit_net_exit, 1293 .id = &hashlimit_net_id, 1294 .size = sizeof(struct hashlimit_net), 1295 }; 1296 1297 static int __init hashlimit_mt_init(void) 1298 { 1299 int err; 1300 1301 err = register_pernet_subsys(&hashlimit_net_ops); 1302 if (err < 0) 1303 return err; 1304 err = xt_register_matches(hashlimit_mt_reg, 1305 ARRAY_SIZE(hashlimit_mt_reg)); 1306 if (err < 0) 1307 goto err1; 1308 1309 err = -ENOMEM; 1310 hashlimit_cachep = kmem_cache_create("xt_hashlimit", 1311 sizeof(struct dsthash_ent), 0, 0, 1312 NULL); 1313 if (!hashlimit_cachep) { 1314 pr_warn("unable to create slab cache\n"); 1315 goto err2; 1316 } 1317 return 0; 1318 1319 err2: 1320 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); 1321 err1: 1322 unregister_pernet_subsys(&hashlimit_net_ops); 1323 return err; 1324 1325 } 1326 1327 static void __exit hashlimit_mt_exit(void) 1328 { 1329 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); 1330 unregister_pernet_subsys(&hashlimit_net_ops); 1331 1332 rcu_barrier_bh(); 1333 kmem_cache_destroy(hashlimit_cachep); 1334 } 1335 1336 module_init(hashlimit_mt_init); 1337 module_exit(hashlimit_mt_exit); 1338