1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * xt_hashlimit - Netfilter module to limit the number of packets per time 4 * separately for each hashbucket (sourceip/sourceport/dstip/dstport) 5 * 6 * (C) 2003-2004 by Harald Welte <laforge@netfilter.org> 7 * (C) 2006-2012 Patrick McHardy <kaber@trash.net> 8 * Copyright �� CC Computer Consultants GmbH, 2007 - 2008 9 * 10 * Development of this code was funded by Astaro AG, http://www.astaro.com/ 11 */ 12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13#include <linux/module.h> 14#include <linux/spinlock.h> 15#include <linux/random.h> 16#include <linux/jhash.h> 17#include <linux/slab.h> 18#include <linux/vmalloc.h> 19#include <linux/proc_fs.h> 20#include <linux/seq_file.h> 21#include <linux/list.h> 22#include <linux/skbuff.h> 23#include <linux/mm.h> 24#include <linux/in.h> 25#include <linux/ip.h> 26#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 27#include <linux/ipv6.h> 28#include <net/ipv6.h> 29#endif 30 31#include <net/net_namespace.h> 32#include <net/netns/generic.h> 33 34#include <linux/netfilter/x_tables.h> 35#include <linux/netfilter_ipv4/ip_tables.h> 36#include <linux/netfilter_ipv6/ip6_tables.h> 37#include <linux/mutex.h> 38#include <linux/kernel.h> 39#include <linux/refcount.h> 40#include <uapi/linux/netfilter/xt_hashlimit.h> 41 42#define XT_HASHLIMIT_ALL (XT_HASHLIMIT_HASH_DIP | XT_HASHLIMIT_HASH_DPT | \ 43 XT_HASHLIMIT_HASH_SIP | XT_HASHLIMIT_HASH_SPT | \ 44 XT_HASHLIMIT_INVERT | XT_HASHLIMIT_BYTES |\ 45 XT_HASHLIMIT_RATE_MATCH) 46 47MODULE_LICENSE("GPL"); 48MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 49MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); 50MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match"); 51MODULE_ALIAS("ipt_hashlimit"); 52MODULE_ALIAS("ip6t_hashlimit"); 53 54struct hashlimit_net { 55 struct hlist_head htables; 56 struct proc_dir_entry *ipt_hashlimit; 57 struct proc_dir_entry *ip6t_hashlimit; 58}; 59 60static unsigned int hashlimit_net_id; 61static inline struct hashlimit_net *hashlimit_pernet(struct net *net) 62{ 63 return net_generic(net, hashlimit_net_id); 64} 65 66/* need to declare this at the top */ 67static const struct seq_operations dl_seq_ops_v2; 68static const struct seq_operations dl_seq_ops_v1; 69static const struct seq_operations dl_seq_ops; 70 71/* hash table crap */ 72struct dsthash_dst { 73 union { 74 struct { 75 __be32 src; 76 __be32 dst; 77 } ip; 78#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 79 struct { 80 __be32 src[4]; 81 __be32 dst[4]; 82 } ip6; 83#endif 84 }; 85 __be16 src_port; 86 __be16 dst_port; 87}; 88 89struct dsthash_ent { 90 /* static / read-only parts in the beginning */ 91 struct hlist_node node; 92 struct dsthash_dst dst; 93 94 /* modified structure members in the end */ 95 spinlock_t lock; 96 unsigned long expires; /* precalculated expiry time */ 97 struct { 98 unsigned long prev; /* last modification */ 99 union { 100 struct { 101 u_int64_t credit; 102 u_int64_t credit_cap; 103 u_int64_t cost; 104 }; 105 struct { 106 u_int32_t interval, prev_window; 107 u_int64_t current_rate; 108 u_int64_t rate; 109 int64_t burst; 110 }; 111 }; 112 } rateinfo; 113 struct rcu_head rcu; 114}; 115 116struct xt_hashlimit_htable { 117 struct hlist_node node; /* global list of all htables */ 118 refcount_t use; 119 u_int8_t family; 120 bool rnd_initialized; 121 122 struct hashlimit_cfg3 cfg; /* config */ 123 124 /* used internally */ 125 spinlock_t lock; /* lock for list_head */ 126 u_int32_t rnd; /* random seed for hash */ 127 unsigned int count; /* number entries in table */ 128 struct delayed_work gc_work; 129 130 /* seq_file stuff */ 131 struct proc_dir_entry *pde; 132 const char *name; 133 struct net *net; 134 135 struct hlist_head hash[]; /* hashtable itself */ 136}; 137 138static int 139cfg_copy(struct hashlimit_cfg3 *to, const void *from, int revision) 140{ 141 if (revision == 1) { 142 struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from; 143 144 to->mode = cfg->mode; 145 to->avg = cfg->avg; 146 to->burst = cfg->burst; 147 to->size = cfg->size; 148 to->max = cfg->max; 149 to->gc_interval = cfg->gc_interval; 150 to->expire = cfg->expire; 151 to->srcmask = cfg->srcmask; 152 to->dstmask = cfg->dstmask; 153 } else if (revision == 2) { 154 struct hashlimit_cfg2 *cfg = (struct hashlimit_cfg2 *)from; 155 156 to->mode = cfg->mode; 157 to->avg = cfg->avg; 158 to->burst = cfg->burst; 159 to->size = cfg->size; 160 to->max = cfg->max; 161 to->gc_interval = cfg->gc_interval; 162 to->expire = cfg->expire; 163 to->srcmask = cfg->srcmask; 164 to->dstmask = cfg->dstmask; 165 } else if (revision == 3) { 166 memcpy(to, from, sizeof(struct hashlimit_cfg3)); 167 } else { 168 return -EINVAL; 169 } 170 171 return 0; 172} 173 174static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */ 175static struct kmem_cache *hashlimit_cachep __read_mostly; 176 177static inline bool dst_cmp(const struct dsthash_ent *ent, 178 const struct dsthash_dst *b) 179{ 180 return !memcmp(&ent->dst, b, sizeof(ent->dst)); 181} 182 183static u_int32_t 184hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst) 185{ 186 u_int32_t hash = jhash2((const u32 *)dst, 187 sizeof(*dst)/sizeof(u32), 188 ht->rnd); 189 /* 190 * Instead of returning hash % ht->cfg.size (implying a divide) 191 * we return the high 32 bits of the (hash * ht->cfg.size) that will 192 * give results between [0 and cfg.size-1] and same hash distribution, 193 * but using a multiply, less expensive than a divide 194 */ 195 return reciprocal_scale(hash, ht->cfg.size); 196} 197 198static struct dsthash_ent * 199dsthash_find(const struct xt_hashlimit_htable *ht, 200 const struct dsthash_dst *dst) 201{ 202 struct dsthash_ent *ent; 203 u_int32_t hash = hash_dst(ht, dst); 204 205 if (!hlist_empty(&ht->hash[hash])) { 206 hlist_for_each_entry_rcu(ent, &ht->hash[hash], node) 207 if (dst_cmp(ent, dst)) { 208 spin_lock(&ent->lock); 209 return ent; 210 } 211 } 212 return NULL; 213} 214 215/* allocate dsthash_ent, initialize dst, put in htable and lock it */ 216static struct dsthash_ent * 217dsthash_alloc_init(struct xt_hashlimit_htable *ht, 218 const struct dsthash_dst *dst, bool *race) 219{ 220 struct dsthash_ent *ent; 221 222 spin_lock(&ht->lock); 223 224 /* Two or more packets may race to create the same entry in the 225 * hashtable, double check if this packet lost race. 226 */ 227 ent = dsthash_find(ht, dst); 228 if (ent != NULL) { 229 spin_unlock(&ht->lock); 230 *race = true; 231 return ent; 232 } 233 234 /* initialize hash with random val at the time we allocate 235 * the first hashtable entry */ 236 if (unlikely(!ht->rnd_initialized)) { 237 get_random_bytes(&ht->rnd, sizeof(ht->rnd)); 238 ht->rnd_initialized = true; 239 } 240 241 if (ht->cfg.max && ht->count >= ht->cfg.max) { 242 /* FIXME: do something. question is what.. */ 243 net_err_ratelimited("max count of %u reached\n", ht->cfg.max); 244 ent = NULL; 245 } else 246 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC); 247 if (ent) { 248 memcpy(&ent->dst, dst, sizeof(ent->dst)); 249 spin_lock_init(&ent->lock); 250 251 spin_lock(&ent->lock); 252 hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]); 253 ht->count++; 254 } 255 spin_unlock(&ht->lock); 256 return ent; 257} 258 259static void dsthash_free_rcu(struct rcu_head *head) 260{ 261 struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu); 262 263 kmem_cache_free(hashlimit_cachep, ent); 264} 265 266static inline void 267dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent) 268{ 269 hlist_del_rcu(&ent->node); 270 call_rcu(&ent->rcu, dsthash_free_rcu); 271 ht->count--; 272} 273static void htable_gc(struct work_struct *work); 274 275static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg, 276 const char *name, u_int8_t family, 277 struct xt_hashlimit_htable **out_hinfo, 278 int revision) 279{ 280 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 281 struct xt_hashlimit_htable *hinfo; 282 const struct seq_operations *ops; 283 unsigned int size, i; 284 unsigned long nr_pages = totalram_pages(); 285 int ret; 286 287 if (cfg->size) { 288 size = cfg->size; 289 } else { 290 size = (nr_pages << PAGE_SHIFT) / 16384 / 291 sizeof(struct hlist_head); 292 if (nr_pages > 1024 * 1024 * 1024 / PAGE_SIZE) 293 size = 8192; 294 if (size < 16) 295 size = 16; 296 } 297 /* FIXME: don't use vmalloc() here or anywhere else -HW */ 298 hinfo = vmalloc(struct_size(hinfo, hash, size)); 299 if (hinfo == NULL) 300 return -ENOMEM; 301 *out_hinfo = hinfo; 302 303 /* copy match config into hashtable config */ 304 ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3); 305 if (ret) { 306 vfree(hinfo); 307 return ret; 308 } 309 310 hinfo->cfg.size = size; 311 if (hinfo->cfg.max == 0) 312 hinfo->cfg.max = 8 * hinfo->cfg.size; 313 else if (hinfo->cfg.max < hinfo->cfg.size) 314 hinfo->cfg.max = hinfo->cfg.size; 315 316 for (i = 0; i < hinfo->cfg.size; i++) 317 INIT_HLIST_HEAD(&hinfo->hash[i]); 318 319 refcount_set(&hinfo->use, 1); 320 hinfo->count = 0; 321 hinfo->family = family; 322 hinfo->rnd_initialized = false; 323 hinfo->name = kstrdup(name, GFP_KERNEL); 324 if (!hinfo->name) { 325 vfree(hinfo); 326 return -ENOMEM; 327 } 328 spin_lock_init(&hinfo->lock); 329 330 switch (revision) { 331 case 1: 332 ops = &dl_seq_ops_v1; 333 break; 334 case 2: 335 ops = &dl_seq_ops_v2; 336 break; 337 default: 338 ops = &dl_seq_ops; 339 } 340 341 hinfo->pde = proc_create_seq_data(name, 0, 342 (family == NFPROTO_IPV4) ? 343 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit, 344 ops, hinfo); 345 if (hinfo->pde == NULL) { 346 kfree(hinfo->name); 347 vfree(hinfo); 348 return -ENOMEM; 349 } 350 hinfo->net = net; 351 352 INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc); 353 queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work, 354 msecs_to_jiffies(hinfo->cfg.gc_interval)); 355 356 hlist_add_head(&hinfo->node, &hashlimit_net->htables); 357 358 return 0; 359} 360 361static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, bool select_all) 362{ 363 unsigned int i; 364 365 for (i = 0; i < ht->cfg.size; i++) { 366 struct dsthash_ent *dh; 367 struct hlist_node *n; 368 369 spin_lock_bh(&ht->lock); 370 hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) { 371 if (time_after_eq(jiffies, dh->expires) || select_all) 372 dsthash_free(ht, dh); 373 } 374 spin_unlock_bh(&ht->lock); 375 cond_resched(); 376 } 377} 378 379static void htable_gc(struct work_struct *work) 380{ 381 struct xt_hashlimit_htable *ht; 382 383 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work); 384 385 htable_selective_cleanup(ht, false); 386 387 queue_delayed_work(system_power_efficient_wq, 388 &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval)); 389} 390 391static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo) 392{ 393 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net); 394 struct proc_dir_entry *parent; 395 396 if (hinfo->family == NFPROTO_IPV4) 397 parent = hashlimit_net->ipt_hashlimit; 398 else 399 parent = hashlimit_net->ip6t_hashlimit; 400 401 if (parent != NULL) 402 remove_proc_entry(hinfo->name, parent); 403} 404 405static struct xt_hashlimit_htable *htable_find_get(struct net *net, 406 const char *name, 407 u_int8_t family) 408{ 409 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 410 struct xt_hashlimit_htable *hinfo; 411 412 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) { 413 if (!strcmp(name, hinfo->name) && 414 hinfo->family == family) { 415 refcount_inc(&hinfo->use); 416 return hinfo; 417 } 418 } 419 return NULL; 420} 421 422static void htable_put(struct xt_hashlimit_htable *hinfo) 423{ 424 if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) { 425 hlist_del(&hinfo->node); 426 htable_remove_proc_entry(hinfo); 427 mutex_unlock(&hashlimit_mutex); 428 429 cancel_delayed_work_sync(&hinfo->gc_work); 430 htable_selective_cleanup(hinfo, true); 431 kfree(hinfo->name); 432 vfree(hinfo); 433 } 434} 435 436/* The algorithm used is the Simple Token Bucket Filter (TBF) 437 * see net/sched/sch_tbf.c in the linux source tree 438 */ 439 440/* Rusty: This is my (non-mathematically-inclined) understanding of 441 this algorithm. The `average rate' in jiffies becomes your initial 442 amount of credit `credit' and the most credit you can ever have 443 `credit_cap'. The `peak rate' becomes the cost of passing the 444 test, `cost'. 445 446 `prev' tracks the last packet hit: you gain one credit per jiffy. 447 If you get credit balance more than this, the extra credit is 448 discarded. Every time the match passes, you lose `cost' credits; 449 if you don't have that many, the test fails. 450 451 See Alexey's formal explanation in net/sched/sch_tbf.c. 452 453 To get the maximum range, we multiply by this factor (ie. you get N 454 credits per jiffy). We want to allow a rate as low as 1 per day 455 (slowest userspace tool allows), which means 456 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie. 457*/ 458#define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24)) 459#define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24)) 460 461/* Repeated shift and or gives us all 1s, final shift and add 1 gives 462 * us the power of 2 below the theoretical max, so GCC simply does a 463 * shift. */ 464#define _POW2_BELOW2(x) ((x)|((x)>>1)) 465#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2)) 466#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4)) 467#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8)) 468#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16)) 469#define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32)) 470#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1) 471#define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1) 472 473#define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ) 474#define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1) 475 476/* in byte mode, the lowest possible rate is one packet/second. 477 * credit_cap is used as a counter that tells us how many times we can 478 * refill the "credits available" counter when it becomes empty. 479 */ 480#define MAX_CPJ_BYTES (0xFFFFFFFF / HZ) 481#define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES) 482 483static u32 xt_hashlimit_len_to_chunks(u32 len) 484{ 485 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1; 486} 487 488/* Precision saver. */ 489static u64 user2credits(u64 user, int revision) 490{ 491 u64 scale = (revision == 1) ? 492 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2; 493 u64 cpj = (revision == 1) ? 494 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY; 495 496 /* Avoid overflow: divide the constant operands first */ 497 if (scale >= HZ * cpj) 498 return div64_u64(user, div64_u64(scale, HZ * cpj)); 499 500 return user * div64_u64(HZ * cpj, scale); 501} 502 503static u32 user2credits_byte(u32 user) 504{ 505 u64 us = user; 506 us *= HZ * CREDITS_PER_JIFFY_BYTES; 507 return (u32) (us >> 32); 508} 509 510static u64 user2rate(u64 user) 511{ 512 if (user != 0) { 513 return div64_u64(XT_HASHLIMIT_SCALE_v2, user); 514 } else { 515 pr_info_ratelimited("invalid rate from userspace: %llu\n", 516 user); 517 return 0; 518 } 519} 520 521static u64 user2rate_bytes(u32 user) 522{ 523 u64 r; 524 525 r = user ? U32_MAX / user : U32_MAX; 526 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT; 527} 528 529static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now, 530 u32 mode, int revision) 531{ 532 unsigned long delta = now - dh->rateinfo.prev; 533 u64 cap, cpj; 534 535 if (delta == 0) 536 return; 537 538 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) { 539 u64 interval = dh->rateinfo.interval * HZ; 540 541 if (delta < interval) 542 return; 543 544 dh->rateinfo.prev = now; 545 dh->rateinfo.prev_window = 546 ((dh->rateinfo.current_rate * interval) > 547 (delta * dh->rateinfo.rate)); 548 dh->rateinfo.current_rate = 0; 549 550 return; 551 } 552 553 dh->rateinfo.prev = now; 554 555 if (mode & XT_HASHLIMIT_BYTES) { 556 u64 tmp = dh->rateinfo.credit; 557 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta; 558 cap = CREDITS_PER_JIFFY_BYTES * HZ; 559 if (tmp >= dh->rateinfo.credit) {/* overflow */ 560 dh->rateinfo.credit = cap; 561 return; 562 } 563 } else { 564 cpj = (revision == 1) ? 565 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY; 566 dh->rateinfo.credit += delta * cpj; 567 cap = dh->rateinfo.credit_cap; 568 } 569 if (dh->rateinfo.credit > cap) 570 dh->rateinfo.credit = cap; 571} 572 573static void rateinfo_init(struct dsthash_ent *dh, 574 struct xt_hashlimit_htable *hinfo, int revision) 575{ 576 dh->rateinfo.prev = jiffies; 577 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) { 578 dh->rateinfo.prev_window = 0; 579 dh->rateinfo.current_rate = 0; 580 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { 581 dh->rateinfo.rate = 582 user2rate_bytes((u32)hinfo->cfg.avg); 583 if (hinfo->cfg.burst) 584 dh->rateinfo.burst = 585 hinfo->cfg.burst * dh->rateinfo.rate; 586 else 587 dh->rateinfo.burst = dh->rateinfo.rate; 588 } else { 589 dh->rateinfo.rate = user2rate(hinfo->cfg.avg); 590 dh->rateinfo.burst = 591 hinfo->cfg.burst + dh->rateinfo.rate; 592 } 593 dh->rateinfo.interval = hinfo->cfg.interval; 594 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) { 595 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ; 596 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg); 597 dh->rateinfo.credit_cap = hinfo->cfg.burst; 598 } else { 599 dh->rateinfo.credit = user2credits(hinfo->cfg.avg * 600 hinfo->cfg.burst, revision); 601 dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision); 602 dh->rateinfo.credit_cap = dh->rateinfo.credit; 603 } 604} 605 606static inline __be32 maskl(__be32 a, unsigned int l) 607{ 608 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0; 609} 610 611#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 612static void hashlimit_ipv6_mask(__be32 *i, unsigned int p) 613{ 614 switch (p) { 615 case 0 ... 31: 616 i[0] = maskl(i[0], p); 617 i[1] = i[2] = i[3] = 0; 618 break; 619 case 32 ... 63: 620 i[1] = maskl(i[1], p - 32); 621 i[2] = i[3] = 0; 622 break; 623 case 64 ... 95: 624 i[2] = maskl(i[2], p - 64); 625 i[3] = 0; 626 break; 627 case 96 ... 127: 628 i[3] = maskl(i[3], p - 96); 629 break; 630 case 128: 631 break; 632 } 633} 634#endif 635 636static int 637hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo, 638 struct dsthash_dst *dst, 639 const struct sk_buff *skb, unsigned int protoff) 640{ 641 __be16 _ports[2], *ports; 642 u8 nexthdr; 643 int poff; 644 645 memset(dst, 0, sizeof(*dst)); 646 647 switch (hinfo->family) { 648 case NFPROTO_IPV4: 649 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) 650 dst->ip.dst = maskl(ip_hdr(skb)->daddr, 651 hinfo->cfg.dstmask); 652 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) 653 dst->ip.src = maskl(ip_hdr(skb)->saddr, 654 hinfo->cfg.srcmask); 655 656 if (!(hinfo->cfg.mode & 657 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT))) 658 return 0; 659 nexthdr = ip_hdr(skb)->protocol; 660 break; 661#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 662 case NFPROTO_IPV6: 663 { 664 __be16 frag_off; 665 666 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) { 667 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr, 668 sizeof(dst->ip6.dst)); 669 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask); 670 } 671 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) { 672 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr, 673 sizeof(dst->ip6.src)); 674 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask); 675 } 676 677 if (!(hinfo->cfg.mode & 678 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT))) 679 return 0; 680 nexthdr = ipv6_hdr(skb)->nexthdr; 681 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off); 682 if ((int)protoff < 0) 683 return -1; 684 break; 685 } 686#endif 687 default: 688 BUG(); 689 return 0; 690 } 691 692 poff = proto_ports_offset(nexthdr); 693 if (poff >= 0) { 694 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports), 695 &_ports); 696 } else { 697 _ports[0] = _ports[1] = 0; 698 ports = _ports; 699 } 700 if (!ports) 701 return -1; 702 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT) 703 dst->src_port = ports[0]; 704 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT) 705 dst->dst_port = ports[1]; 706 return 0; 707} 708 709static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh) 710{ 711 u64 tmp = xt_hashlimit_len_to_chunks(len); 712 tmp = tmp * dh->rateinfo.cost; 713 714 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ)) 715 tmp = CREDITS_PER_JIFFY_BYTES * HZ; 716 717 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) { 718 dh->rateinfo.credit_cap--; 719 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ; 720 } 721 return (u32) tmp; 722} 723 724static bool 725hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par, 726 struct xt_hashlimit_htable *hinfo, 727 const struct hashlimit_cfg3 *cfg, int revision) 728{ 729 unsigned long now = jiffies; 730 struct dsthash_ent *dh; 731 struct dsthash_dst dst; 732 bool race = false; 733 u64 cost; 734 735 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0) 736 goto hotdrop; 737 738 local_bh_disable(); 739 dh = dsthash_find(hinfo, &dst); 740 if (dh == NULL) { 741 dh = dsthash_alloc_init(hinfo, &dst, &race); 742 if (dh == NULL) { 743 local_bh_enable(); 744 goto hotdrop; 745 } else if (race) { 746 /* Already got an entry, update expiration timeout */ 747 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); 748 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision); 749 } else { 750 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire); 751 rateinfo_init(dh, hinfo, revision); 752 } 753 } else { 754 /* update expiration timeout */ 755 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire); 756 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision); 757 } 758 759 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) { 760 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1; 761 dh->rateinfo.current_rate += cost; 762 763 if (!dh->rateinfo.prev_window && 764 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) { 765 spin_unlock(&dh->lock); 766 local_bh_enable(); 767 return !(cfg->mode & XT_HASHLIMIT_INVERT); 768 } else { 769 goto overlimit; 770 } 771 } 772 773 if (cfg->mode & XT_HASHLIMIT_BYTES) 774 cost = hashlimit_byte_cost(skb->len, dh); 775 else 776 cost = dh->rateinfo.cost; 777 778 if (dh->rateinfo.credit >= cost) { 779 /* below the limit */ 780 dh->rateinfo.credit -= cost; 781 spin_unlock(&dh->lock); 782 local_bh_enable(); 783 return !(cfg->mode & XT_HASHLIMIT_INVERT); 784 } 785 786overlimit: 787 spin_unlock(&dh->lock); 788 local_bh_enable(); 789 /* default match is underlimit - so over the limit, we need to invert */ 790 return cfg->mode & XT_HASHLIMIT_INVERT; 791 792 hotdrop: 793 par->hotdrop = true; 794 return false; 795} 796 797static bool 798hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) 799{ 800 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 801 struct xt_hashlimit_htable *hinfo = info->hinfo; 802 struct hashlimit_cfg3 cfg = {}; 803 int ret; 804 805 ret = cfg_copy(&cfg, (void *)&info->cfg, 1); 806 if (ret) 807 return ret; 808 809 return hashlimit_mt_common(skb, par, hinfo, &cfg, 1); 810} 811 812static bool 813hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par) 814{ 815 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 816 struct xt_hashlimit_htable *hinfo = info->hinfo; 817 struct hashlimit_cfg3 cfg = {}; 818 int ret; 819 820 ret = cfg_copy(&cfg, (void *)&info->cfg, 2); 821 if (ret) 822 return ret; 823 824 return hashlimit_mt_common(skb, par, hinfo, &cfg, 2); 825} 826 827static bool 828hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par) 829{ 830 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 831 struct xt_hashlimit_htable *hinfo = info->hinfo; 832 833 return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3); 834} 835 836#define HASHLIMIT_MAX_SIZE 1048576 837 838static int hashlimit_mt_check_common(const struct xt_mtchk_param *par, 839 struct xt_hashlimit_htable **hinfo, 840 struct hashlimit_cfg3 *cfg, 841 const char *name, int revision) 842{ 843 struct net *net = par->net; 844 int ret; 845 846 if (cfg->gc_interval == 0 || cfg->expire == 0) 847 return -EINVAL; 848 if (cfg->size > HASHLIMIT_MAX_SIZE) { 849 cfg->size = HASHLIMIT_MAX_SIZE; 850 pr_info_ratelimited("size too large, truncated to %u\n", cfg->size); 851 } 852 if (cfg->max > HASHLIMIT_MAX_SIZE) { 853 cfg->max = HASHLIMIT_MAX_SIZE; 854 pr_info_ratelimited("max too large, truncated to %u\n", cfg->max); 855 } 856 if (par->family == NFPROTO_IPV4) { 857 if (cfg->srcmask > 32 || cfg->dstmask > 32) 858 return -EINVAL; 859 } else { 860 if (cfg->srcmask > 128 || cfg->dstmask > 128) 861 return -EINVAL; 862 } 863 864 if (cfg->mode & ~XT_HASHLIMIT_ALL) { 865 pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n", 866 cfg->mode); 867 return -EINVAL; 868 } 869 870 /* Check for overflow. */ 871 if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) { 872 if (cfg->avg == 0 || cfg->avg > U32_MAX) { 873 pr_info_ratelimited("invalid rate\n"); 874 return -ERANGE; 875 } 876 877 if (cfg->interval == 0) { 878 pr_info_ratelimited("invalid interval\n"); 879 return -EINVAL; 880 } 881 } else if (cfg->mode & XT_HASHLIMIT_BYTES) { 882 if (user2credits_byte(cfg->avg) == 0) { 883 pr_info_ratelimited("overflow, rate too high: %llu\n", 884 cfg->avg); 885 return -EINVAL; 886 } 887 } else if (cfg->burst == 0 || 888 user2credits(cfg->avg * cfg->burst, revision) < 889 user2credits(cfg->avg, revision)) { 890 pr_info_ratelimited("overflow, try lower: %llu/%llu\n", 891 cfg->avg, cfg->burst); 892 return -ERANGE; 893 } 894 895 mutex_lock(&hashlimit_mutex); 896 *hinfo = htable_find_get(net, name, par->family); 897 if (*hinfo == NULL) { 898 ret = htable_create(net, cfg, name, par->family, 899 hinfo, revision); 900 if (ret < 0) { 901 mutex_unlock(&hashlimit_mutex); 902 return ret; 903 } 904 } 905 mutex_unlock(&hashlimit_mutex); 906 907 return 0; 908} 909 910static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par) 911{ 912 struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 913 struct hashlimit_cfg3 cfg = {}; 914 int ret; 915 916 ret = xt_check_proc_name(info->name, sizeof(info->name)); 917 if (ret) 918 return ret; 919 920 ret = cfg_copy(&cfg, (void *)&info->cfg, 1); 921 if (ret) 922 return ret; 923 924 return hashlimit_mt_check_common(par, &info->hinfo, 925 &cfg, info->name, 1); 926} 927 928static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par) 929{ 930 struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 931 struct hashlimit_cfg3 cfg = {}; 932 int ret; 933 934 ret = xt_check_proc_name(info->name, sizeof(info->name)); 935 if (ret) 936 return ret; 937 938 ret = cfg_copy(&cfg, (void *)&info->cfg, 2); 939 if (ret) 940 return ret; 941 942 return hashlimit_mt_check_common(par, &info->hinfo, 943 &cfg, info->name, 2); 944} 945 946static int hashlimit_mt_check(const struct xt_mtchk_param *par) 947{ 948 struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 949 int ret; 950 951 ret = xt_check_proc_name(info->name, sizeof(info->name)); 952 if (ret) 953 return ret; 954 955 return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg, 956 info->name, 3); 957} 958 959static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par) 960{ 961 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo; 962 963 htable_put(info->hinfo); 964} 965 966static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par) 967{ 968 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo; 969 970 htable_put(info->hinfo); 971} 972 973static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par) 974{ 975 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo; 976 977 htable_put(info->hinfo); 978} 979 980static struct xt_match hashlimit_mt_reg[] __read_mostly = { 981 { 982 .name = "hashlimit", 983 .revision = 1, 984 .family = NFPROTO_IPV4, 985 .match = hashlimit_mt_v1, 986 .matchsize = sizeof(struct xt_hashlimit_mtinfo1), 987 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo), 988 .checkentry = hashlimit_mt_check_v1, 989 .destroy = hashlimit_mt_destroy_v1, 990 .me = THIS_MODULE, 991 }, 992 { 993 .name = "hashlimit", 994 .revision = 2, 995 .family = NFPROTO_IPV4, 996 .match = hashlimit_mt_v2, 997 .matchsize = sizeof(struct xt_hashlimit_mtinfo2), 998 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo), 999 .checkentry = hashlimit_mt_check_v2, 1000 .destroy = hashlimit_mt_destroy_v2, 1001 .me = THIS_MODULE, 1002 }, 1003 { 1004 .name = "hashlimit", 1005 .revision = 3, 1006 .family = NFPROTO_IPV4, 1007 .match = hashlimit_mt, 1008 .matchsize = sizeof(struct xt_hashlimit_mtinfo3), 1009 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo), 1010 .checkentry = hashlimit_mt_check, 1011 .destroy = hashlimit_mt_destroy, 1012 .me = THIS_MODULE, 1013 }, 1014#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1015 { 1016 .name = "hashlimit", 1017 .revision = 1, 1018 .family = NFPROTO_IPV6, 1019 .match = hashlimit_mt_v1, 1020 .matchsize = sizeof(struct xt_hashlimit_mtinfo1), 1021 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo), 1022 .checkentry = hashlimit_mt_check_v1, 1023 .destroy = hashlimit_mt_destroy_v1, 1024 .me = THIS_MODULE, 1025 }, 1026 { 1027 .name = "hashlimit", 1028 .revision = 2, 1029 .family = NFPROTO_IPV6, 1030 .match = hashlimit_mt_v2, 1031 .matchsize = sizeof(struct xt_hashlimit_mtinfo2), 1032 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo), 1033 .checkentry = hashlimit_mt_check_v2, 1034 .destroy = hashlimit_mt_destroy_v2, 1035 .me = THIS_MODULE, 1036 }, 1037 { 1038 .name = "hashlimit", 1039 .revision = 3, 1040 .family = NFPROTO_IPV6, 1041 .match = hashlimit_mt, 1042 .matchsize = sizeof(struct xt_hashlimit_mtinfo3), 1043 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo), 1044 .checkentry = hashlimit_mt_check, 1045 .destroy = hashlimit_mt_destroy, 1046 .me = THIS_MODULE, 1047 }, 1048#endif 1049}; 1050 1051/* PROC stuff */ 1052static void *dl_seq_start(struct seq_file *s, loff_t *pos) 1053 __acquires(htable->lock) 1054{ 1055 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file)); 1056 unsigned int *bucket; 1057 1058 spin_lock_bh(&htable->lock); 1059 if (*pos >= htable->cfg.size) 1060 return NULL; 1061 1062 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC); 1063 if (!bucket) 1064 return ERR_PTR(-ENOMEM); 1065 1066 *bucket = *pos; 1067 return bucket; 1068} 1069 1070static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos) 1071{ 1072 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file)); 1073 unsigned int *bucket = v; 1074 1075 *pos = ++(*bucket); 1076 if (*pos >= htable->cfg.size) { 1077 kfree(v); 1078 return NULL; 1079 } 1080 return bucket; 1081} 1082 1083static void dl_seq_stop(struct seq_file *s, void *v) 1084 __releases(htable->lock) 1085{ 1086 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file)); 1087 unsigned int *bucket = v; 1088 1089 if (!IS_ERR(bucket)) 1090 kfree(bucket); 1091 spin_unlock_bh(&htable->lock); 1092} 1093 1094static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family, 1095 struct seq_file *s) 1096{ 1097 switch (family) { 1098 case NFPROTO_IPV4: 1099 seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n", 1100 (long)(ent->expires - jiffies)/HZ, 1101 &ent->dst.ip.src, 1102 ntohs(ent->dst.src_port), 1103 &ent->dst.ip.dst, 1104 ntohs(ent->dst.dst_port), 1105 ent->rateinfo.credit, ent->rateinfo.credit_cap, 1106 ent->rateinfo.cost); 1107 break; 1108#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1109 case NFPROTO_IPV6: 1110 seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n", 1111 (long)(ent->expires - jiffies)/HZ, 1112 &ent->dst.ip6.src, 1113 ntohs(ent->dst.src_port), 1114 &ent->dst.ip6.dst, 1115 ntohs(ent->dst.dst_port), 1116 ent->rateinfo.credit, ent->rateinfo.credit_cap, 1117 ent->rateinfo.cost); 1118 break; 1119#endif 1120 default: 1121 BUG(); 1122 } 1123} 1124 1125static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family, 1126 struct seq_file *s) 1127{ 1128 struct xt_hashlimit_htable *ht = pde_data(file_inode(s->file)); 1129 1130 spin_lock(&ent->lock); 1131 /* recalculate to show accurate numbers */ 1132 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2); 1133 1134 dl_seq_print(ent, family, s); 1135 1136 spin_unlock(&ent->lock); 1137 return seq_has_overflowed(s); 1138} 1139 1140static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family, 1141 struct seq_file *s) 1142{ 1143 struct xt_hashlimit_htable *ht = pde_data(file_inode(s->file)); 1144 1145 spin_lock(&ent->lock); 1146 /* recalculate to show accurate numbers */ 1147 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1); 1148 1149 dl_seq_print(ent, family, s); 1150 1151 spin_unlock(&ent->lock); 1152 return seq_has_overflowed(s); 1153} 1154 1155static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family, 1156 struct seq_file *s) 1157{ 1158 struct xt_hashlimit_htable *ht = pde_data(file_inode(s->file)); 1159 1160 spin_lock(&ent->lock); 1161 /* recalculate to show accurate numbers */ 1162 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3); 1163 1164 dl_seq_print(ent, family, s); 1165 1166 spin_unlock(&ent->lock); 1167 return seq_has_overflowed(s); 1168} 1169 1170static int dl_seq_show_v2(struct seq_file *s, void *v) 1171{ 1172 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file)); 1173 unsigned int *bucket = (unsigned int *)v; 1174 struct dsthash_ent *ent; 1175 1176 if (!hlist_empty(&htable->hash[*bucket])) { 1177 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1178 if (dl_seq_real_show_v2(ent, htable->family, s)) 1179 return -1; 1180 } 1181 return 0; 1182} 1183 1184static int dl_seq_show_v1(struct seq_file *s, void *v) 1185{ 1186 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file)); 1187 unsigned int *bucket = v; 1188 struct dsthash_ent *ent; 1189 1190 if (!hlist_empty(&htable->hash[*bucket])) { 1191 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1192 if (dl_seq_real_show_v1(ent, htable->family, s)) 1193 return -1; 1194 } 1195 return 0; 1196} 1197 1198static int dl_seq_show(struct seq_file *s, void *v) 1199{ 1200 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file)); 1201 unsigned int *bucket = v; 1202 struct dsthash_ent *ent; 1203 1204 if (!hlist_empty(&htable->hash[*bucket])) { 1205 hlist_for_each_entry(ent, &htable->hash[*bucket], node) 1206 if (dl_seq_real_show(ent, htable->family, s)) 1207 return -1; 1208 } 1209 return 0; 1210} 1211 1212static const struct seq_operations dl_seq_ops_v1 = { 1213 .start = dl_seq_start, 1214 .next = dl_seq_next, 1215 .stop = dl_seq_stop, 1216 .show = dl_seq_show_v1 1217}; 1218 1219static const struct seq_operations dl_seq_ops_v2 = { 1220 .start = dl_seq_start, 1221 .next = dl_seq_next, 1222 .stop = dl_seq_stop, 1223 .show = dl_seq_show_v2 1224}; 1225 1226static const struct seq_operations dl_seq_ops = { 1227 .start = dl_seq_start, 1228 .next = dl_seq_next, 1229 .stop = dl_seq_stop, 1230 .show = dl_seq_show 1231}; 1232 1233static int __net_init hashlimit_proc_net_init(struct net *net) 1234{ 1235 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1236 1237 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net); 1238 if (!hashlimit_net->ipt_hashlimit) 1239 return -ENOMEM; 1240#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1241 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net); 1242 if (!hashlimit_net->ip6t_hashlimit) { 1243 remove_proc_entry("ipt_hashlimit", net->proc_net); 1244 return -ENOMEM; 1245 } 1246#endif 1247 return 0; 1248} 1249 1250static void __net_exit hashlimit_proc_net_exit(struct net *net) 1251{ 1252 struct xt_hashlimit_htable *hinfo; 1253 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1254 1255 /* hashlimit_net_exit() is called before hashlimit_mt_destroy(). 1256 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc 1257 * entries is empty before trying to remove it. 1258 */ 1259 mutex_lock(&hashlimit_mutex); 1260 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) 1261 htable_remove_proc_entry(hinfo); 1262 hashlimit_net->ipt_hashlimit = NULL; 1263 hashlimit_net->ip6t_hashlimit = NULL; 1264 mutex_unlock(&hashlimit_mutex); 1265 1266 remove_proc_entry("ipt_hashlimit", net->proc_net); 1267#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 1268 remove_proc_entry("ip6t_hashlimit", net->proc_net); 1269#endif 1270} 1271 1272static int __net_init hashlimit_net_init(struct net *net) 1273{ 1274 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net); 1275 1276 INIT_HLIST_HEAD(&hashlimit_net->htables); 1277 return hashlimit_proc_net_init(net); 1278} 1279 1280static void __net_exit hashlimit_net_exit(struct net *net) 1281{ 1282 hashlimit_proc_net_exit(net); 1283} 1284 1285static struct pernet_operations hashlimit_net_ops = { 1286 .init = hashlimit_net_init, 1287 .exit = hashlimit_net_exit, 1288 .id = &hashlimit_net_id, 1289 .size = sizeof(struct hashlimit_net), 1290}; 1291 1292static int __init hashlimit_mt_init(void) 1293{ 1294 int err; 1295 1296 err = register_pernet_subsys(&hashlimit_net_ops); 1297 if (err < 0) 1298 return err; 1299 err = xt_register_matches(hashlimit_mt_reg, 1300 ARRAY_SIZE(hashlimit_mt_reg)); 1301 if (err < 0) 1302 goto err1; 1303 1304 err = -ENOMEM; 1305 hashlimit_cachep = kmem_cache_create("xt_hashlimit", 1306 sizeof(struct dsthash_ent), 0, 0, 1307 NULL); 1308 if (!hashlimit_cachep) { 1309 pr_warn("unable to create slab cache\n"); 1310 goto err2; 1311 } 1312 return 0; 1313 1314err2: 1315 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); 1316err1: 1317 unregister_pernet_subsys(&hashlimit_net_ops); 1318 return err; 1319 1320} 1321 1322static void __exit hashlimit_mt_exit(void) 1323{ 1324 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg)); 1325 unregister_pernet_subsys(&hashlimit_net_ops); 1326 1327 rcu_barrier(); 1328 kmem_cache_destroy(hashlimit_cachep); 1329} 1330 1331module_init(hashlimit_mt_init); 1332module_exit(hashlimit_mt_exit); 1333