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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 <[email protected]>
7 * (C) 2006-2012 Patrick McHardy <[email protected]>
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/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/mutex.h>
37#include <linux/kernel.h>
38#include <linux/refcount.h>
39#include <uapi/linux/netfilter/xt_hashlimit.h>
40
41#define XT_HASHLIMIT_ALL (XT_HASHLIMIT_HASH_DIP | XT_HASHLIMIT_HASH_DPT | \
42 XT_HASHLIMIT_HASH_SIP | XT_HASHLIMIT_HASH_SPT | \
43 XT_HASHLIMIT_INVERT | XT_HASHLIMIT_BYTES |\
44 XT_HASHLIMIT_RATE_MATCH)
45
46MODULE_LICENSE("GPL");
47MODULE_AUTHOR("Harald Welte <[email protected]>");
48MODULE_AUTHOR("Jan Engelhardt <[email protected]>");
49MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
50MODULE_ALIAS("ipt_hashlimit");
51MODULE_ALIAS("ip6t_hashlimit");
52
53struct hashlimit_net {
54 struct hlist_head htables;
55 struct proc_dir_entry *ipt_hashlimit;
56 struct proc_dir_entry *ip6t_hashlimit;
57};
58
59static unsigned int hashlimit_net_id;
60static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
61{
62 return net_generic(net, hashlimit_net_id);
63}
64
65/* need to declare this at the top */
66static const struct seq_operations dl_seq_ops_v2;
67static const struct seq_operations dl_seq_ops_v1;
68static const struct seq_operations dl_seq_ops;
69
70/* hash table crap */
71struct dsthash_dst {
72 union {
73 struct {
74 __be32 src;
75 __be32 dst;
76 } ip;
77#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
78 struct {
79 __be32 src[4];
80 __be32 dst[4];
81 } ip6;
82#endif
83 };
84 __be16 src_port;
85 __be16 dst_port;
86};
87
88struct dsthash_ent {
89 /* static / read-only parts in the beginning */
90 struct hlist_node node;
91 struct dsthash_dst dst;
92
93 /* modified structure members in the end */
94 spinlock_t lock;
95 unsigned long expires; /* precalculated expiry time */
96 struct {
97 unsigned long prev; /* last modification */
98 union {
99 struct {
100 u_int64_t credit;
101 u_int64_t credit_cap;
102 u_int64_t cost;
103 };
104 struct {
105 u_int32_t interval, prev_window;
106 u_int64_t current_rate;
107 u_int64_t rate;
108 int64_t burst;
109 };
110 };
111 } rateinfo;
112 struct rcu_head rcu;
113};
114
115struct xt_hashlimit_htable {
116 struct hlist_node node; /* global list of all htables */
117 refcount_t use;
118 u_int8_t family;
119 bool rnd_initialized;
120 bool ratematch;
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 hinfo = kvmalloc_flex(*hinfo, hash, size);
298 if (hinfo == NULL)
299 return -ENOMEM;
300 *out_hinfo = hinfo;
301
302 /* copy match config into hashtable config */
303 ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3);
304 if (ret) {
305 kvfree(hinfo);
306 return ret;
307 }
308
309 hinfo->cfg.size = size;
310 if (hinfo->cfg.max == 0)
311 hinfo->cfg.max = 8 * hinfo->cfg.size;
312 else if (hinfo->cfg.max < hinfo->cfg.size)
313 hinfo->cfg.max = hinfo->cfg.size;
314
315 for (i = 0; i < hinfo->cfg.size; i++)
316 INIT_HLIST_HEAD(&hinfo->hash[i]);
317
318 refcount_set(&hinfo->use, 1);
319 hinfo->count = 0;
320 hinfo->family = family;
321 hinfo->rnd_initialized = false;
322 hinfo->name = kstrdup(name, GFP_KERNEL);
323 if (!hinfo->name) {
324 kvfree(hinfo);
325 return -ENOMEM;
326 }
327 hinfo->ratematch = !!(cfg->mode & XT_HASHLIMIT_RATE_MATCH);
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 kvfree(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 hlist_head *head = &ht->hash[i];
367 struct dsthash_ent *dh;
368 struct hlist_node *n;
369
370 if (hlist_empty(head))
371 continue;
372
373 spin_lock_bh(&ht->lock);
374 hlist_for_each_entry_safe(dh, n, head, node) {
375 if (time_after_eq(jiffies, dh->expires) || select_all)
376 dsthash_free(ht, dh);
377 }
378 spin_unlock_bh(&ht->lock);
379 cond_resched();
380 }
381}
382
383static void htable_gc(struct work_struct *work)
384{
385 struct xt_hashlimit_htable *ht;
386
387 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
388
389 htable_selective_cleanup(ht, false);
390
391 queue_delayed_work(system_power_efficient_wq,
392 &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval));
393}
394
395static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
396{
397 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
398 struct proc_dir_entry *parent;
399
400 if (hinfo->family == NFPROTO_IPV4)
401 parent = hashlimit_net->ipt_hashlimit;
402 else
403 parent = hashlimit_net->ip6t_hashlimit;
404
405 if (parent != NULL)
406 remove_proc_entry(hinfo->name, parent);
407}
408
409static struct xt_hashlimit_htable *htable_find_get(struct net *net,
410 const char *name,
411 u_int8_t family)
412{
413 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
414 struct xt_hashlimit_htable *hinfo;
415
416 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
417 if (!strcmp(name, hinfo->name) &&
418 hinfo->family == family) {
419 refcount_inc(&hinfo->use);
420 return hinfo;
421 }
422 }
423 return NULL;
424}
425
426static void htable_put(struct xt_hashlimit_htable *hinfo)
427{
428 if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) {
429 hlist_del(&hinfo->node);
430 htable_remove_proc_entry(hinfo);
431 mutex_unlock(&hashlimit_mutex);
432
433 cancel_delayed_work_sync(&hinfo->gc_work);
434 htable_selective_cleanup(hinfo, true);
435 kfree(hinfo->name);
436 kvfree(hinfo);
437 }
438}
439
440/* The algorithm used is the Simple Token Bucket Filter (TBF)
441 * see net/sched/sch_tbf.c in the linux source tree
442 */
443
444/* Rusty: This is my (non-mathematically-inclined) understanding of
445 this algorithm. The `average rate' in jiffies becomes your initial
446 amount of credit `credit' and the most credit you can ever have
447 `credit_cap'. The `peak rate' becomes the cost of passing the
448 test, `cost'.
449
450 `prev' tracks the last packet hit: you gain one credit per jiffy.
451 If you get credit balance more than this, the extra credit is
452 discarded. Every time the match passes, you lose `cost' credits;
453 if you don't have that many, the test fails.
454
455 See Alexey's formal explanation in net/sched/sch_tbf.c.
456
457 To get the maximum range, we multiply by this factor (ie. you get N
458 credits per jiffy). We want to allow a rate as low as 1 per day
459 (slowest userspace tool allows), which means
460 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
461*/
462#define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24))
463#define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24))
464
465/* Repeated shift and or gives us all 1s, final shift and add 1 gives
466 * us the power of 2 below the theoretical max, so GCC simply does a
467 * shift. */
468#define _POW2_BELOW2(x) ((x)|((x)>>1))
469#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
470#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
471#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
472#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
473#define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32))
474#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
475#define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1)
476
477#define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ)
478#define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1)
479
480/* in byte mode, the lowest possible rate is one packet/second.
481 * credit_cap is used as a counter that tells us how many times we can
482 * refill the "credits available" counter when it becomes empty.
483 */
484#define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
485#define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
486
487static u32 xt_hashlimit_len_to_chunks(u32 len)
488{
489 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
490}
491
492/* Precision saver. */
493static u64 user2credits(u64 user, int revision)
494{
495 u64 scale = (revision == 1) ?
496 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
497 u64 cpj = (revision == 1) ?
498 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
499
500 /* Avoid overflow: divide the constant operands first */
501 if (scale >= HZ * cpj)
502 return div64_u64(user, div64_u64(scale, HZ * cpj));
503
504 return user * div64_u64(HZ * cpj, scale);
505}
506
507static u32 user2credits_byte(u32 user)
508{
509 u64 us = user;
510 us *= HZ * CREDITS_PER_JIFFY_BYTES;
511 return (u32) (us >> 32);
512}
513
514static u64 user2rate(u64 user)
515{
516 if (user != 0) {
517 return div64_u64(XT_HASHLIMIT_SCALE_v2, user);
518 } else {
519 pr_info_ratelimited("invalid rate from userspace: %llu\n",
520 user);
521 return 0;
522 }
523}
524
525static u64 user2rate_bytes(u32 user)
526{
527 u64 r;
528
529 r = user ? U32_MAX / user : U32_MAX;
530 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT;
531}
532
533static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now,
534 u32 mode, int revision)
535{
536 unsigned long delta = now - dh->rateinfo.prev;
537 u64 cap, cpj;
538
539 if (delta == 0)
540 return;
541
542 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) {
543 u64 interval = dh->rateinfo.interval * HZ;
544
545 if (delta < interval)
546 return;
547
548 dh->rateinfo.prev = now;
549 dh->rateinfo.prev_window =
550 ((dh->rateinfo.current_rate * interval) >
551 (delta * dh->rateinfo.rate));
552 dh->rateinfo.current_rate = 0;
553
554 return;
555 }
556
557 dh->rateinfo.prev = now;
558
559 if (mode & XT_HASHLIMIT_BYTES) {
560 u64 tmp = dh->rateinfo.credit;
561 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
562 cap = CREDITS_PER_JIFFY_BYTES * HZ;
563 if (tmp >= dh->rateinfo.credit) {/* overflow */
564 dh->rateinfo.credit = cap;
565 return;
566 }
567 } else {
568 cpj = (revision == 1) ?
569 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
570 dh->rateinfo.credit += delta * cpj;
571 cap = dh->rateinfo.credit_cap;
572 }
573 if (dh->rateinfo.credit > cap)
574 dh->rateinfo.credit = cap;
575}
576
577static void rateinfo_init(struct dsthash_ent *dh,
578 struct xt_hashlimit_htable *hinfo, int revision)
579{
580 dh->rateinfo.prev = jiffies;
581 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) {
582 dh->rateinfo.prev_window = 0;
583 dh->rateinfo.current_rate = 0;
584 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
585 dh->rateinfo.rate =
586 user2rate_bytes((u32)hinfo->cfg.avg);
587 if (hinfo->cfg.burst)
588 dh->rateinfo.burst =
589 hinfo->cfg.burst * dh->rateinfo.rate;
590 else
591 dh->rateinfo.burst = dh->rateinfo.rate;
592 } else {
593 dh->rateinfo.rate = user2rate(hinfo->cfg.avg);
594 dh->rateinfo.burst =
595 hinfo->cfg.burst + dh->rateinfo.rate;
596 }
597 dh->rateinfo.interval = hinfo->cfg.interval;
598 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
599 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
600 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg);
601 dh->rateinfo.credit_cap = hinfo->cfg.burst;
602 } else {
603 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
604 hinfo->cfg.burst, revision);
605 dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision);
606 dh->rateinfo.credit_cap = dh->rateinfo.credit;
607 }
608}
609
610static inline __be32 maskl(__be32 a, unsigned int l)
611{
612 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
613}
614
615#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
616static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
617{
618 switch (p) {
619 case 0 ... 31:
620 i[0] = maskl(i[0], p);
621 i[1] = i[2] = i[3] = 0;
622 break;
623 case 32 ... 63:
624 i[1] = maskl(i[1], p - 32);
625 i[2] = i[3] = 0;
626 break;
627 case 64 ... 95:
628 i[2] = maskl(i[2], p - 64);
629 i[3] = 0;
630 break;
631 case 96 ... 127:
632 i[3] = maskl(i[3], p - 96);
633 break;
634 case 128:
635 break;
636 }
637}
638#endif
639
640static int
641hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
642 struct dsthash_dst *dst,
643 const struct sk_buff *skb, unsigned int protoff)
644{
645 __be16 _ports[2], *ports;
646 u8 nexthdr;
647 int poff;
648
649 memset(dst, 0, sizeof(*dst));
650
651 switch (hinfo->family) {
652 case NFPROTO_IPV4:
653 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
654 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
655 hinfo->cfg.dstmask);
656 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
657 dst->ip.src = maskl(ip_hdr(skb)->saddr,
658 hinfo->cfg.srcmask);
659
660 if (!(hinfo->cfg.mode &
661 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
662 return 0;
663 if (ntohs(ip_hdr(skb)->frag_off) & IP_OFFSET)
664 return -1;
665 nexthdr = ip_hdr(skb)->protocol;
666 break;
667#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
668 case NFPROTO_IPV6:
669 {
670 __be16 frag_off;
671
672 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
673 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
674 sizeof(dst->ip6.dst));
675 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
676 }
677 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
678 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
679 sizeof(dst->ip6.src));
680 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
681 }
682
683 if (!(hinfo->cfg.mode &
684 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
685 return 0;
686 nexthdr = ipv6_hdr(skb)->nexthdr;
687 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off);
688 if ((int)protoff < 0 || ntohs(frag_off) & IP6_OFFSET)
689 return -1;
690 break;
691 }
692#endif
693 default:
694 BUG();
695 return 0;
696 }
697
698 poff = proto_ports_offset(nexthdr);
699 if (poff >= 0) {
700 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
701 &_ports);
702 } else {
703 _ports[0] = _ports[1] = 0;
704 ports = _ports;
705 }
706 if (!ports)
707 return -1;
708 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
709 dst->src_port = ports[0];
710 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
711 dst->dst_port = ports[1];
712 return 0;
713}
714
715static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
716{
717 u64 tmp = xt_hashlimit_len_to_chunks(len);
718 tmp = tmp * dh->rateinfo.cost;
719
720 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
721 tmp = CREDITS_PER_JIFFY_BYTES * HZ;
722
723 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
724 dh->rateinfo.credit_cap--;
725 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
726 }
727 return (u32) tmp;
728}
729
730static bool
731hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
732 struct xt_hashlimit_htable *hinfo,
733 const struct hashlimit_cfg3 *cfg, int revision)
734{
735 unsigned long now = jiffies;
736 struct dsthash_ent *dh;
737 struct dsthash_dst dst;
738 bool race = false;
739 u64 cost;
740
741 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
742 goto hotdrop;
743
744 local_bh_disable();
745 dh = dsthash_find(hinfo, &dst);
746 if (dh == NULL) {
747 dh = dsthash_alloc_init(hinfo, &dst, &race);
748 if (dh == NULL) {
749 local_bh_enable();
750 goto hotdrop;
751 } else if (race) {
752 /* Already got an entry, update expiration timeout */
753 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
754 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
755 } else {
756 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
757 rateinfo_init(dh, hinfo, revision);
758 }
759 } else {
760 /* update expiration timeout */
761 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
762 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
763 }
764
765 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
766 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1;
767 dh->rateinfo.current_rate += cost;
768
769 if (!dh->rateinfo.prev_window &&
770 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
771 spin_unlock(&dh->lock);
772 local_bh_enable();
773 return !(cfg->mode & XT_HASHLIMIT_INVERT);
774 } else {
775 goto overlimit;
776 }
777 }
778
779 if (cfg->mode & XT_HASHLIMIT_BYTES)
780 cost = hashlimit_byte_cost(skb->len, dh);
781 else
782 cost = dh->rateinfo.cost;
783
784 if (dh->rateinfo.credit >= cost) {
785 /* below the limit */
786 dh->rateinfo.credit -= cost;
787 spin_unlock(&dh->lock);
788 local_bh_enable();
789 return !(cfg->mode & XT_HASHLIMIT_INVERT);
790 }
791
792overlimit:
793 spin_unlock(&dh->lock);
794 local_bh_enable();
795 /* default match is underlimit - so over the limit, we need to invert */
796 return cfg->mode & XT_HASHLIMIT_INVERT;
797
798 hotdrop:
799 par->hotdrop = true;
800 return false;
801}
802
803static bool
804hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
805{
806 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
807 struct xt_hashlimit_htable *hinfo = info->hinfo;
808 struct hashlimit_cfg3 cfg = {};
809 int ret;
810
811 ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
812 if (ret)
813 return ret;
814
815 return hashlimit_mt_common(skb, par, hinfo, &cfg, 1);
816}
817
818static bool
819hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
820{
821 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
822 struct xt_hashlimit_htable *hinfo = info->hinfo;
823 struct hashlimit_cfg3 cfg = {};
824 int ret;
825
826 ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
827 if (ret)
828 return ret;
829
830 return hashlimit_mt_common(skb, par, hinfo, &cfg, 2);
831}
832
833static bool
834hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
835{
836 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
837 struct xt_hashlimit_htable *hinfo = info->hinfo;
838
839 return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3);
840}
841
842#define HASHLIMIT_MAX_SIZE 1048576
843
844static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
845 struct xt_hashlimit_htable **hinfo,
846 struct hashlimit_cfg3 *cfg,
847 const char *name, int revision)
848{
849 struct net *net = par->net;
850 int ret;
851
852 if (cfg->gc_interval == 0 || cfg->expire == 0)
853 return -EINVAL;
854 if (cfg->size > HASHLIMIT_MAX_SIZE) {
855 cfg->size = HASHLIMIT_MAX_SIZE;
856 pr_info_ratelimited("size too large, truncated to %u\n", cfg->size);
857 }
858 if (cfg->max > HASHLIMIT_MAX_SIZE) {
859 cfg->max = HASHLIMIT_MAX_SIZE;
860 pr_info_ratelimited("max too large, truncated to %u\n", cfg->max);
861 }
862 if (par->family == NFPROTO_IPV4) {
863 if (cfg->srcmask > 32 || cfg->dstmask > 32)
864 return -EINVAL;
865 } else {
866 if (cfg->srcmask > 128 || cfg->dstmask > 128)
867 return -EINVAL;
868 }
869
870 if (cfg->mode & ~XT_HASHLIMIT_ALL) {
871 pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n",
872 cfg->mode);
873 return -EINVAL;
874 }
875
876 /* Check for overflow. */
877 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
878 if (revision < 3)
879 return -EINVAL;
880
881 if (cfg->avg == 0 || cfg->avg > U32_MAX) {
882 pr_info_ratelimited("invalid rate\n");
883 return -ERANGE;
884 }
885
886 if (cfg->interval == 0) {
887 pr_info_ratelimited("invalid interval\n");
888 return -EINVAL;
889 }
890 } else if (cfg->mode & XT_HASHLIMIT_BYTES) {
891 if (user2credits_byte(cfg->avg) == 0) {
892 pr_info_ratelimited("overflow, rate too high: %llu\n",
893 cfg->avg);
894 return -EINVAL;
895 }
896 } else if (cfg->burst == 0 ||
897 user2credits(cfg->avg * cfg->burst, revision) <
898 user2credits(cfg->avg, revision)) {
899 pr_info_ratelimited("overflow, try lower: %llu/%llu\n",
900 cfg->avg, cfg->burst);
901 return -ERANGE;
902 }
903
904 mutex_lock(&hashlimit_mutex);
905 *hinfo = htable_find_get(net, name, par->family);
906 if (*hinfo == NULL) {
907 ret = htable_create(net, cfg, name, par->family,
908 hinfo, revision);
909 if (ret < 0) {
910 mutex_unlock(&hashlimit_mutex);
911 return ret;
912 }
913 } else {
914 if ((cfg->mode & XT_HASHLIMIT_RATE_MATCH &&
915 !(*hinfo)->ratematch) ||
916 (!(cfg->mode & XT_HASHLIMIT_RATE_MATCH) &&
917 (*hinfo)->ratematch)) {
918 mutex_unlock(&hashlimit_mutex);
919 htable_put(*hinfo);
920 return -EINVAL;
921 }
922 }
923 mutex_unlock(&hashlimit_mutex);
924
925 return 0;
926}
927
928static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par)
929{
930 struct xt_hashlimit_mtinfo1 *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, 1);
939 if (ret)
940 return ret;
941
942 return hashlimit_mt_check_common(par, &info->hinfo,
943 &cfg, info->name, 1);
944}
945
946static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par)
947{
948 struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
949 struct hashlimit_cfg3 cfg = {};
950 int ret;
951
952 ret = xt_check_proc_name(info->name, sizeof(info->name));
953 if (ret)
954 return ret;
955
956 ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
957 if (ret)
958 return ret;
959
960 return hashlimit_mt_check_common(par, &info->hinfo,
961 &cfg, info->name, 2);
962}
963
964static int hashlimit_mt_check(const struct xt_mtchk_param *par)
965{
966 struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
967 int ret;
968
969 ret = xt_check_proc_name(info->name, sizeof(info->name));
970 if (ret)
971 return ret;
972
973 return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg,
974 info->name, 3);
975}
976
977static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par)
978{
979 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
980
981 htable_put(info->hinfo);
982}
983
984static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par)
985{
986 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
987
988 htable_put(info->hinfo);
989}
990
991static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
992{
993 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
994
995 htable_put(info->hinfo);
996}
997
998static struct xt_match hashlimit_mt_reg[] __read_mostly = {
999 {
1000 .name = "hashlimit",
1001 .revision = 1,
1002 .family = NFPROTO_IPV4,
1003 .match = hashlimit_mt_v1,
1004 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
1005 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
1006 .checkentry = hashlimit_mt_check_v1,
1007 .destroy = hashlimit_mt_destroy_v1,
1008 .me = THIS_MODULE,
1009 },
1010 {
1011 .name = "hashlimit",
1012 .revision = 2,
1013 .family = NFPROTO_IPV4,
1014 .match = hashlimit_mt_v2,
1015 .matchsize = sizeof(struct xt_hashlimit_mtinfo2),
1016 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
1017 .checkentry = hashlimit_mt_check_v2,
1018 .destroy = hashlimit_mt_destroy_v2,
1019 .me = THIS_MODULE,
1020 },
1021 {
1022 .name = "hashlimit",
1023 .revision = 3,
1024 .family = NFPROTO_IPV4,
1025 .match = hashlimit_mt,
1026 .matchsize = sizeof(struct xt_hashlimit_mtinfo3),
1027 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1028 .checkentry = hashlimit_mt_check,
1029 .destroy = hashlimit_mt_destroy,
1030 .me = THIS_MODULE,
1031 },
1032#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1033 {
1034 .name = "hashlimit",
1035 .revision = 1,
1036 .family = NFPROTO_IPV6,
1037 .match = hashlimit_mt_v1,
1038 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
1039 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
1040 .checkentry = hashlimit_mt_check_v1,
1041 .destroy = hashlimit_mt_destroy_v1,
1042 .me = THIS_MODULE,
1043 },
1044 {
1045 .name = "hashlimit",
1046 .revision = 2,
1047 .family = NFPROTO_IPV6,
1048 .match = hashlimit_mt_v2,
1049 .matchsize = sizeof(struct xt_hashlimit_mtinfo2),
1050 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
1051 .checkentry = hashlimit_mt_check_v2,
1052 .destroy = hashlimit_mt_destroy_v2,
1053 .me = THIS_MODULE,
1054 },
1055 {
1056 .name = "hashlimit",
1057 .revision = 3,
1058 .family = NFPROTO_IPV6,
1059 .match = hashlimit_mt,
1060 .matchsize = sizeof(struct xt_hashlimit_mtinfo3),
1061 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1062 .checkentry = hashlimit_mt_check,
1063 .destroy = hashlimit_mt_destroy,
1064 .me = THIS_MODULE,
1065 },
1066#endif
1067};
1068
1069/* PROC stuff */
1070static void *dl_seq_start(struct seq_file *s, loff_t *pos)
1071 __acquires(htable->lock)
1072{
1073 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file));
1074 unsigned int *bucket;
1075
1076 spin_lock_bh(&htable->lock);
1077 if (*pos >= htable->cfg.size)
1078 return NULL;
1079
1080 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
1081 if (!bucket)
1082 return ERR_PTR(-ENOMEM);
1083
1084 *bucket = *pos;
1085 return bucket;
1086}
1087
1088static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
1089{
1090 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file));
1091 unsigned int *bucket = v;
1092
1093 *pos = ++(*bucket);
1094 if (*pos >= htable->cfg.size) {
1095 kfree(v);
1096 return NULL;
1097 }
1098 return bucket;
1099}
1100
1101static void dl_seq_stop(struct seq_file *s, void *v)
1102 __releases(htable->lock)
1103{
1104 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file));
1105 unsigned int *bucket = v;
1106
1107 if (!IS_ERR(bucket))
1108 kfree(bucket);
1109 spin_unlock_bh(&htable->lock);
1110}
1111
1112static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family,
1113 struct seq_file *s)
1114{
1115 switch (family) {
1116 case NFPROTO_IPV4:
1117 seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n",
1118 (long)(ent->expires - jiffies)/HZ,
1119 &ent->dst.ip.src,
1120 ntohs(ent->dst.src_port),
1121 &ent->dst.ip.dst,
1122 ntohs(ent->dst.dst_port),
1123 ent->rateinfo.credit, ent->rateinfo.credit_cap,
1124 ent->rateinfo.cost);
1125 break;
1126#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1127 case NFPROTO_IPV6:
1128 seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n",
1129 (long)(ent->expires - jiffies)/HZ,
1130 &ent->dst.ip6.src,
1131 ntohs(ent->dst.src_port),
1132 &ent->dst.ip6.dst,
1133 ntohs(ent->dst.dst_port),
1134 ent->rateinfo.credit, ent->rateinfo.credit_cap,
1135 ent->rateinfo.cost);
1136 break;
1137#endif
1138 default:
1139 BUG();
1140 }
1141}
1142
1143static int dl_seq_real_show_v2(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, 2);
1151
1152 dl_seq_print(ent, family, s);
1153
1154 spin_unlock(&ent->lock);
1155 return seq_has_overflowed(s);
1156}
1157
1158static int dl_seq_real_show_v1(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, 1);
1166
1167 dl_seq_print(ent, family, s);
1168
1169 spin_unlock(&ent->lock);
1170 return seq_has_overflowed(s);
1171}
1172
1173static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
1174 struct seq_file *s)
1175{
1176 struct xt_hashlimit_htable *ht = pde_data(file_inode(s->file));
1177
1178 spin_lock(&ent->lock);
1179 /* recalculate to show accurate numbers */
1180 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3);
1181
1182 dl_seq_print(ent, family, s);
1183
1184 spin_unlock(&ent->lock);
1185 return seq_has_overflowed(s);
1186}
1187
1188static int dl_seq_show_v2(struct seq_file *s, void *v)
1189{
1190 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file));
1191 unsigned int *bucket = (unsigned int *)v;
1192 struct dsthash_ent *ent;
1193
1194 if (!hlist_empty(&htable->hash[*bucket])) {
1195 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1196 if (dl_seq_real_show_v2(ent, htable->family, s))
1197 return -1;
1198 }
1199 return 0;
1200}
1201
1202static int dl_seq_show_v1(struct seq_file *s, void *v)
1203{
1204 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file));
1205 unsigned int *bucket = v;
1206 struct dsthash_ent *ent;
1207
1208 if (!hlist_empty(&htable->hash[*bucket])) {
1209 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1210 if (dl_seq_real_show_v1(ent, htable->family, s))
1211 return -1;
1212 }
1213 return 0;
1214}
1215
1216static int dl_seq_show(struct seq_file *s, void *v)
1217{
1218 struct xt_hashlimit_htable *htable = pde_data(file_inode(s->file));
1219 unsigned int *bucket = v;
1220 struct dsthash_ent *ent;
1221
1222 if (!hlist_empty(&htable->hash[*bucket])) {
1223 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1224 if (dl_seq_real_show(ent, htable->family, s))
1225 return -1;
1226 }
1227 return 0;
1228}
1229
1230static const struct seq_operations dl_seq_ops_v1 = {
1231 .start = dl_seq_start,
1232 .next = dl_seq_next,
1233 .stop = dl_seq_stop,
1234 .show = dl_seq_show_v1
1235};
1236
1237static const struct seq_operations dl_seq_ops_v2 = {
1238 .start = dl_seq_start,
1239 .next = dl_seq_next,
1240 .stop = dl_seq_stop,
1241 .show = dl_seq_show_v2
1242};
1243
1244static const struct seq_operations dl_seq_ops = {
1245 .start = dl_seq_start,
1246 .next = dl_seq_next,
1247 .stop = dl_seq_stop,
1248 .show = dl_seq_show
1249};
1250
1251static int __net_init hashlimit_proc_net_init(struct net *net)
1252{
1253 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1254
1255 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
1256 if (!hashlimit_net->ipt_hashlimit)
1257 return -ENOMEM;
1258#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1259 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
1260 if (!hashlimit_net->ip6t_hashlimit) {
1261 remove_proc_entry("ipt_hashlimit", net->proc_net);
1262 return -ENOMEM;
1263 }
1264#endif
1265 return 0;
1266}
1267
1268static void __net_exit hashlimit_proc_net_exit(struct net *net)
1269{
1270 struct xt_hashlimit_htable *hinfo;
1271 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1272
1273 /* hashlimit_net_exit() is called before hashlimit_mt_destroy().
1274 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc
1275 * entries is empty before trying to remove it.
1276 */
1277 mutex_lock(&hashlimit_mutex);
1278 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node)
1279 htable_remove_proc_entry(hinfo);
1280 hashlimit_net->ipt_hashlimit = NULL;
1281 hashlimit_net->ip6t_hashlimit = NULL;
1282 mutex_unlock(&hashlimit_mutex);
1283
1284 remove_proc_entry("ipt_hashlimit", net->proc_net);
1285#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1286 remove_proc_entry("ip6t_hashlimit", net->proc_net);
1287#endif
1288}
1289
1290static int __net_init hashlimit_net_init(struct net *net)
1291{
1292 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1293
1294 INIT_HLIST_HEAD(&hashlimit_net->htables);
1295 return hashlimit_proc_net_init(net);
1296}
1297
1298static void __net_exit hashlimit_net_exit(struct net *net)
1299{
1300 hashlimit_proc_net_exit(net);
1301}
1302
1303static struct pernet_operations hashlimit_net_ops = {
1304 .init = hashlimit_net_init,
1305 .exit = hashlimit_net_exit,
1306 .id = &hashlimit_net_id,
1307 .size = sizeof(struct hashlimit_net),
1308};
1309
1310static int __init hashlimit_mt_init(void)
1311{
1312 int err;
1313
1314 err = register_pernet_subsys(&hashlimit_net_ops);
1315 if (err < 0)
1316 return err;
1317 err = xt_register_matches(hashlimit_mt_reg,
1318 ARRAY_SIZE(hashlimit_mt_reg));
1319 if (err < 0)
1320 goto err1;
1321
1322 err = -ENOMEM;
1323 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
1324 sizeof(struct dsthash_ent), 0, 0,
1325 NULL);
1326 if (!hashlimit_cachep) {
1327 pr_warn("unable to create slab cache\n");
1328 goto err2;
1329 }
1330 return 0;
1331
1332err2:
1333 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1334err1:
1335 unregister_pernet_subsys(&hashlimit_net_ops);
1336 return err;
1337
1338}
1339
1340static void __exit hashlimit_mt_exit(void)
1341{
1342 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1343 unregister_pernet_subsys(&hashlimit_net_ops);
1344
1345 rcu_barrier();
1346 kmem_cache_destroy(hashlimit_cachep);
1347}
1348
1349module_init(hashlimit_mt_init);
1350module_exit(hashlimit_mt_exit);