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Input: atmel_mxt_ts - don't try to free unallocated kernel memory
[linux/fpc-iii.git] / net / netfilter / xt_hashlimit.c
blob1ad4017f9b7349849d845c9e5bb9a5592533a291
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 if (ret) {
299 vfree(hinfo);
300 return ret;
301 }
302
303 hinfo->cfg.size = size;
304 if (hinfo->cfg.max == 0)
305 hinfo->cfg.max = 8 * hinfo->cfg.size;
306 else if (hinfo->cfg.max < hinfo->cfg.size)
307 hinfo->cfg.max = hinfo->cfg.size;
308
309 for (i = 0; i < hinfo->cfg.size; i++)
310 INIT_HLIST_HEAD(&hinfo->hash[i]);
311
312 hinfo->use = 1;
313 hinfo->count = 0;
314 hinfo->family = family;
315 hinfo->rnd_initialized = false;
316 hinfo->name = kstrdup(name, GFP_KERNEL);
317 if (!hinfo->name) {
318 vfree(hinfo);
319 return -ENOMEM;
320 }
321 spin_lock_init(&hinfo->lock);
322
323 switch (revision) {
324 case 1:
325 ops = &dl_seq_ops_v1;
326 break;
327 case 2:
328 ops = &dl_seq_ops_v2;
329 break;
330 default:
331 ops = &dl_seq_ops;
332 }
333
334 hinfo->pde = proc_create_seq_data(name, 0,
335 (family == NFPROTO_IPV4) ?
336 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
337 ops, hinfo);
338 if (hinfo->pde == NULL) {
339 kfree(hinfo->name);
340 vfree(hinfo);
341 return -ENOMEM;
342 }
343 hinfo->net = net;
344
345 INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc);
346 queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work,
347 msecs_to_jiffies(hinfo->cfg.gc_interval));
348
349 hlist_add_head(&hinfo->node, &hashlimit_net->htables);
350
351 return 0;
352 }
353
354 static bool select_all(const struct xt_hashlimit_htable *ht,
355 const struct dsthash_ent *he)
356 {
357 return true;
358 }
359
360 static bool select_gc(const struct xt_hashlimit_htable *ht,
361 const struct dsthash_ent *he)
362 {
363 return time_after_eq(jiffies, he->expires);
364 }
365
366 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
367 bool (*select)(const struct xt_hashlimit_htable *ht,
368 const struct dsthash_ent *he))
369 {
370 unsigned int i;
371
372 for (i = 0; i < ht->cfg.size; i++) {
373 struct dsthash_ent *dh;
374 struct hlist_node *n;
375
376 spin_lock_bh(&ht->lock);
377 hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) {
378 if ((*select)(ht, dh))
379 dsthash_free(ht, dh);
380 }
381 spin_unlock_bh(&ht->lock);
382 cond_resched();
383 }
384 }
385
386 static void htable_gc(struct work_struct *work)
387 {
388 struct xt_hashlimit_htable *ht;
389
390 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
391
392 htable_selective_cleanup(ht, select_gc);
393
394 queue_delayed_work(system_power_efficient_wq,
395 &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval));
396 }
397
398 static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
399 {
400 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
401 struct proc_dir_entry *parent;
402
403 if (hinfo->family == NFPROTO_IPV4)
404 parent = hashlimit_net->ipt_hashlimit;
405 else
406 parent = hashlimit_net->ip6t_hashlimit;
407
408 if (parent != NULL)
409 remove_proc_entry(hinfo->name, parent);
410 }
411
412 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
413 {
414 cancel_delayed_work_sync(&hinfo->gc_work);
415 htable_remove_proc_entry(hinfo);
416 htable_selective_cleanup(hinfo, select_all);
417 kfree(hinfo->name);
418 vfree(hinfo);
419 }
420
421 static struct xt_hashlimit_htable *htable_find_get(struct net *net,
422 const char *name,
423 u_int8_t family)
424 {
425 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
426 struct xt_hashlimit_htable *hinfo;
427
428 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
429 if (!strcmp(name, hinfo->name) &&
430 hinfo->family == family) {
431 hinfo->use++;
432 return hinfo;
433 }
434 }
435 return NULL;
436 }
437
438 static void htable_put(struct xt_hashlimit_htable *hinfo)
439 {
440 mutex_lock(&hashlimit_mutex);
441 if (--hinfo->use == 0) {
442 hlist_del(&hinfo->node);
443 htable_destroy(hinfo);
444 }
445 mutex_unlock(&hashlimit_mutex);
446 }
447
448 /* The algorithm used is the Simple Token Bucket Filter (TBF)
449 * see net/sched/sch_tbf.c in the linux source tree
450 */
451
452 /* Rusty: This is my (non-mathematically-inclined) understanding of
453 this algorithm. The `average rate' in jiffies becomes your initial
454 amount of credit `credit' and the most credit you can ever have
455 `credit_cap'. The `peak rate' becomes the cost of passing the
456 test, `cost'.
457
458 `prev' tracks the last packet hit: you gain one credit per jiffy.
459 If you get credit balance more than this, the extra credit is
460 discarded. Every time the match passes, you lose `cost' credits;
461 if you don't have that many, the test fails.
462
463 See Alexey's formal explanation in net/sched/sch_tbf.c.
464
465 To get the maximum range, we multiply by this factor (ie. you get N
466 credits per jiffy). We want to allow a rate as low as 1 per day
467 (slowest userspace tool allows), which means
468 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
469 */
470 #define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24))
471 #define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24))
472
473 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
474 * us the power of 2 below the theoretical max, so GCC simply does a
475 * shift. */
476 #define _POW2_BELOW2(x) ((x)|((x)>>1))
477 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
478 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
479 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
480 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
481 #define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32))
482 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
483 #define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1)
484
485 #define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ)
486 #define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1)
487
488 /* in byte mode, the lowest possible rate is one packet/second.
489 * credit_cap is used as a counter that tells us how many times we can
490 * refill the "credits available" counter when it becomes empty.
491 */
492 #define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
493 #define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
494
495 static u32 xt_hashlimit_len_to_chunks(u32 len)
496 {
497 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
498 }
499
500 /* Precision saver. */
501 static u64 user2credits(u64 user, int revision)
502 {
503 u64 scale = (revision == 1) ?
504 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
505 u64 cpj = (revision == 1) ?
506 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
507
508 /* Avoid overflow: divide the constant operands first */
509 if (scale >= HZ * cpj)
510 return div64_u64(user, div64_u64(scale, HZ * cpj));
511
512 return user * div64_u64(HZ * cpj, scale);
513 }
514
515 static u32 user2credits_byte(u32 user)
516 {
517 u64 us = user;
518 us *= HZ * CREDITS_PER_JIFFY_BYTES;
519 return (u32) (us >> 32);
520 }
521
522 static u64 user2rate(u64 user)
523 {
524 if (user != 0) {
525 return div64_u64(XT_HASHLIMIT_SCALE_v2, user);
526 } else {
527 pr_info_ratelimited("invalid rate from userspace: %llu\n",
528 user);
529 return 0;
530 }
531 }
532
533 static u64 user2rate_bytes(u32 user)
534 {
535 u64 r;
536
537 r = user ? U32_MAX / user : U32_MAX;
538 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT;
539 }
540
541 static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now,
542 u32 mode, int revision)
543 {
544 unsigned long delta = now - dh->rateinfo.prev;
545 u64 cap, cpj;
546
547 if (delta == 0)
548 return;
549
550 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) {
551 u64 interval = dh->rateinfo.interval * HZ;
552
553 if (delta < interval)
554 return;
555
556 dh->rateinfo.prev = now;
557 dh->rateinfo.prev_window =
558 ((dh->rateinfo.current_rate * interval) >
559 (delta * dh->rateinfo.rate));
560 dh->rateinfo.current_rate = 0;
561
562 return;
563 }
564
565 dh->rateinfo.prev = now;
566
567 if (mode & XT_HASHLIMIT_BYTES) {
568 u64 tmp = dh->rateinfo.credit;
569 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
570 cap = CREDITS_PER_JIFFY_BYTES * HZ;
571 if (tmp >= dh->rateinfo.credit) {/* overflow */
572 dh->rateinfo.credit = cap;
573 return;
574 }
575 } else {
576 cpj = (revision == 1) ?
577 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
578 dh->rateinfo.credit += delta * cpj;
579 cap = dh->rateinfo.credit_cap;
580 }
581 if (dh->rateinfo.credit > cap)
582 dh->rateinfo.credit = cap;
583 }
584
585 static void rateinfo_init(struct dsthash_ent *dh,
586 struct xt_hashlimit_htable *hinfo, int revision)
587 {
588 dh->rateinfo.prev = jiffies;
589 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) {
590 dh->rateinfo.prev_window = 0;
591 dh->rateinfo.current_rate = 0;
592 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
593 dh->rateinfo.rate =
594 user2rate_bytes((u32)hinfo->cfg.avg);
595 if (hinfo->cfg.burst)
596 dh->rateinfo.burst =
597 hinfo->cfg.burst * dh->rateinfo.rate;
598 else
599 dh->rateinfo.burst = dh->rateinfo.rate;
600 } else {
601 dh->rateinfo.rate = user2rate(hinfo->cfg.avg);
602 dh->rateinfo.burst =
603 hinfo->cfg.burst + dh->rateinfo.rate;
604 }
605 dh->rateinfo.interval = hinfo->cfg.interval;
606 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
607 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
608 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg);
609 dh->rateinfo.credit_cap = hinfo->cfg.burst;
610 } else {
611 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
612 hinfo->cfg.burst, revision);
613 dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision);
614 dh->rateinfo.credit_cap = dh->rateinfo.credit;
615 }
616 }
617
618 static inline __be32 maskl(__be32 a, unsigned int l)
619 {
620 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
621 }
622
623 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
624 static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
625 {
626 switch (p) {
627 case 0 ... 31:
628 i[0] = maskl(i[0], p);
629 i[1] = i[2] = i[3] = 0;
630 break;
631 case 32 ... 63:
632 i[1] = maskl(i[1], p - 32);
633 i[2] = i[3] = 0;
634 break;
635 case 64 ... 95:
636 i[2] = maskl(i[2], p - 64);
637 i[3] = 0;
638 break;
639 case 96 ... 127:
640 i[3] = maskl(i[3], p - 96);
641 break;
642 case 128:
643 break;
644 }
645 }
646 #endif
647
648 static int
649 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
650 struct dsthash_dst *dst,
651 const struct sk_buff *skb, unsigned int protoff)
652 {
653 __be16 _ports[2], *ports;
654 u8 nexthdr;
655 int poff;
656
657 memset(dst, 0, sizeof(*dst));
658
659 switch (hinfo->family) {
660 case NFPROTO_IPV4:
661 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
662 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
663 hinfo->cfg.dstmask);
664 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
665 dst->ip.src = maskl(ip_hdr(skb)->saddr,
666 hinfo->cfg.srcmask);
667
668 if (!(hinfo->cfg.mode &
669 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
670 return 0;
671 nexthdr = ip_hdr(skb)->protocol;
672 break;
673 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
674 case NFPROTO_IPV6:
675 {
676 __be16 frag_off;
677
678 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
679 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
680 sizeof(dst->ip6.dst));
681 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
682 }
683 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
684 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
685 sizeof(dst->ip6.src));
686 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
687 }
688
689 if (!(hinfo->cfg.mode &
690 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
691 return 0;
692 nexthdr = ipv6_hdr(skb)->nexthdr;
693 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off);
694 if ((int)protoff < 0)
695 return -1;
696 break;
697 }
698 #endif
699 default:
700 BUG();
701 return 0;
702 }
703
704 poff = proto_ports_offset(nexthdr);
705 if (poff >= 0) {
706 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
707 &_ports);
708 } else {
709 _ports[0] = _ports[1] = 0;
710 ports = _ports;
711 }
712 if (!ports)
713 return -1;
714 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
715 dst->src_port = ports[0];
716 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
717 dst->dst_port = ports[1];
718 return 0;
719 }
720
721 static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
722 {
723 u64 tmp = xt_hashlimit_len_to_chunks(len);
724 tmp = tmp * dh->rateinfo.cost;
725
726 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
727 tmp = CREDITS_PER_JIFFY_BYTES * HZ;
728
729 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
730 dh->rateinfo.credit_cap--;
731 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
732 }
733 return (u32) tmp;
734 }
735
736 static bool
737 hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
738 struct xt_hashlimit_htable *hinfo,
739 const struct hashlimit_cfg3 *cfg, int revision)
740 {
741 unsigned long now = jiffies;
742 struct dsthash_ent *dh;
743 struct dsthash_dst dst;
744 bool race = false;
745 u64 cost;
746
747 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
748 goto hotdrop;
749
750 local_bh_disable();
751 dh = dsthash_find(hinfo, &dst);
752 if (dh == NULL) {
753 dh = dsthash_alloc_init(hinfo, &dst, &race);
754 if (dh == NULL) {
755 local_bh_enable();
756 goto hotdrop;
757 } else if (race) {
758 /* Already got an entry, update expiration timeout */
759 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
760 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
761 } else {
762 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
763 rateinfo_init(dh, hinfo, revision);
764 }
765 } else {
766 /* update expiration timeout */
767 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
768 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
769 }
770
771 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
772 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1;
773 dh->rateinfo.current_rate += cost;
774
775 if (!dh->rateinfo.prev_window &&
776 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
777 spin_unlock(&dh->lock);
778 local_bh_enable();
779 return !(cfg->mode & XT_HASHLIMIT_INVERT);
780 } else {
781 goto overlimit;
782 }
783 }
784
785 if (cfg->mode & XT_HASHLIMIT_BYTES)
786 cost = hashlimit_byte_cost(skb->len, dh);
787 else
788 cost = dh->rateinfo.cost;
789
790 if (dh->rateinfo.credit >= cost) {
791 /* below the limit */
792 dh->rateinfo.credit -= cost;
793 spin_unlock(&dh->lock);
794 local_bh_enable();
795 return !(cfg->mode & XT_HASHLIMIT_INVERT);
796 }
797
798 overlimit:
799 spin_unlock(&dh->lock);
800 local_bh_enable();
801 /* default match is underlimit - so over the limit, we need to invert */
802 return cfg->mode & XT_HASHLIMIT_INVERT;
803
804 hotdrop:
805 par->hotdrop = true;
806 return false;
807 }
808
809 static bool
810 hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
811 {
812 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
813 struct xt_hashlimit_htable *hinfo = info->hinfo;
814 struct hashlimit_cfg3 cfg = {};
815 int ret;
816
817 ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
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 if (ret)
834 return ret;
835
836 return hashlimit_mt_common(skb, par, hinfo, &cfg, 2);
837 }
838
839 static bool
840 hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
841 {
842 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
843 struct xt_hashlimit_htable *hinfo = info->hinfo;
844
845 return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3);
846 }
847
848 static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
849 struct xt_hashlimit_htable **hinfo,
850 struct hashlimit_cfg3 *cfg,
851 const char *name, int revision)
852 {
853 struct net *net = par->net;
854 int ret;
855
856 if (cfg->gc_interval == 0 || cfg->expire == 0)
857 return -EINVAL;
858 if (par->family == NFPROTO_IPV4) {
859 if (cfg->srcmask > 32 || cfg->dstmask > 32)
860 return -EINVAL;
861 } else {
862 if (cfg->srcmask > 128 || cfg->dstmask > 128)
863 return -EINVAL;
864 }
865
866 if (cfg->mode & ~XT_HASHLIMIT_ALL) {
867 pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n",
868 cfg->mode);
869 return -EINVAL;
870 }
871
872 /* Check for overflow. */
873 if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
874 if (cfg->avg == 0 || cfg->avg > U32_MAX) {
875 pr_info_ratelimited("invalid rate\n");
876 return -ERANGE;
877 }
878
879 if (cfg->interval == 0) {
880 pr_info_ratelimited("invalid interval\n");
881 return -EINVAL;
882 }
883 } else if (cfg->mode & XT_HASHLIMIT_BYTES) {
884 if (user2credits_byte(cfg->avg) == 0) {
885 pr_info_ratelimited("overflow, rate too high: %llu\n",
886 cfg->avg);
887 return -EINVAL;
888 }
889 } else if (cfg->burst == 0 ||
890 user2credits(cfg->avg * cfg->burst, revision) <
891 user2credits(cfg->avg, revision)) {
892 pr_info_ratelimited("overflow, try lower: %llu/%llu\n",
893 cfg->avg, cfg->burst);
894 return -ERANGE;
895 }
896
897 mutex_lock(&hashlimit_mutex);
898 *hinfo = htable_find_get(net, name, par->family);
899 if (*hinfo == NULL) {
900 ret = htable_create(net, cfg, name, par->family,
901 hinfo, revision);
902 if (ret < 0) {
903 mutex_unlock(&hashlimit_mutex);
904 return ret;
905 }
906 }
907 mutex_unlock(&hashlimit_mutex);
908
909 return 0;
910 }
911
912 static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par)
913 {
914 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
915 struct hashlimit_cfg3 cfg = {};
916 int ret;
917
918 ret = xt_check_proc_name(info->name, sizeof(info->name));
919 if (ret)
920 return ret;
921
922 ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
923 if (ret)
924 return ret;
925
926 return hashlimit_mt_check_common(par, &info->hinfo,
927 &cfg, info->name, 1);
928 }
929
930 static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par)
931 {
932 struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
933 struct hashlimit_cfg3 cfg = {};
934 int ret;
935
936 ret = xt_check_proc_name(info->name, sizeof(info->name));
937 if (ret)
938 return ret;
939
940 ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
941 if (ret)
942 return ret;
943
944 return hashlimit_mt_check_common(par, &info->hinfo,
945 &cfg, info->name, 2);
946 }
947
948 static int hashlimit_mt_check(const struct xt_mtchk_param *par)
949 {
950 struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
951 int ret;
952
953 ret = xt_check_proc_name(info->name, sizeof(info->name));
954 if (ret)
955 return ret;
956
957 return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg,
958 info->name, 3);
959 }
960
961 static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par)
962 {
963 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
964
965 htable_put(info->hinfo);
966 }
967
968 static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par)
969 {
970 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
971
972 htable_put(info->hinfo);
973 }
974
975 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
976 {
977 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
978
979 htable_put(info->hinfo);
980 }
981
982 static struct xt_match hashlimit_mt_reg[] __read_mostly = {
983 {
984 .name = "hashlimit",
985 .revision = 1,
986 .family = NFPROTO_IPV4,
987 .match = hashlimit_mt_v1,
988 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
989 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
990 .checkentry = hashlimit_mt_check_v1,
991 .destroy = hashlimit_mt_destroy_v1,
992 .me = THIS_MODULE,
993 },
994 {
995 .name = "hashlimit",
996 .revision = 2,
997 .family = NFPROTO_IPV4,
998 .match = hashlimit_mt_v2,
999 .matchsize = sizeof(struct xt_hashlimit_mtinfo2),
1000 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
1001 .checkentry = hashlimit_mt_check_v2,
1002 .destroy = hashlimit_mt_destroy_v2,
1003 .me = THIS_MODULE,
1004 },
1005 {
1006 .name = "hashlimit",
1007 .revision = 3,
1008 .family = NFPROTO_IPV4,
1009 .match = hashlimit_mt,
1010 .matchsize = sizeof(struct xt_hashlimit_mtinfo3),
1011 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1012 .checkentry = hashlimit_mt_check,
1013 .destroy = hashlimit_mt_destroy,
1014 .me = THIS_MODULE,
1015 },
1016 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1017 {
1018 .name = "hashlimit",
1019 .revision = 1,
1020 .family = NFPROTO_IPV6,
1021 .match = hashlimit_mt_v1,
1022 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
1023 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
1024 .checkentry = hashlimit_mt_check_v1,
1025 .destroy = hashlimit_mt_destroy_v1,
1026 .me = THIS_MODULE,
1027 },
1028 {
1029 .name = "hashlimit",
1030 .revision = 2,
1031 .family = NFPROTO_IPV6,
1032 .match = hashlimit_mt_v2,
1033 .matchsize = sizeof(struct xt_hashlimit_mtinfo2),
1034 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
1035 .checkentry = hashlimit_mt_check_v2,
1036 .destroy = hashlimit_mt_destroy_v2,
1037 .me = THIS_MODULE,
1038 },
1039 {
1040 .name = "hashlimit",
1041 .revision = 3,
1042 .family = NFPROTO_IPV6,
1043 .match = hashlimit_mt,
1044 .matchsize = sizeof(struct xt_hashlimit_mtinfo3),
1045 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1046 .checkentry = hashlimit_mt_check,
1047 .destroy = hashlimit_mt_destroy,
1048 .me = THIS_MODULE,
1049 },
1050 #endif
1051 };
1052
1053 /* PROC stuff */
1054 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
1055 __acquires(htable->lock)
1056 {
1057 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1058 unsigned int *bucket;
1059
1060 spin_lock_bh(&htable->lock);
1061 if (*pos >= htable->cfg.size)
1062 return NULL;
1063
1064 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
1065 if (!bucket)
1066 return ERR_PTR(-ENOMEM);
1067
1068 *bucket = *pos;
1069 return bucket;
1070 }
1071
1072 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
1073 {
1074 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1075 unsigned int *bucket = v;
1076
1077 *pos = ++(*bucket);
1078 if (*pos >= htable->cfg.size) {
1079 kfree(v);
1080 return NULL;
1081 }
1082 return bucket;
1083 }
1084
1085 static void dl_seq_stop(struct seq_file *s, void *v)
1086 __releases(htable->lock)
1087 {
1088 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1089 unsigned int *bucket = v;
1090
1091 if (!IS_ERR(bucket))
1092 kfree(bucket);
1093 spin_unlock_bh(&htable->lock);
1094 }
1095
1096 static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family,
1097 struct seq_file *s)
1098 {
1099 switch (family) {
1100 case NFPROTO_IPV4:
1101 seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n",
1102 (long)(ent->expires - jiffies)/HZ,
1103 &ent->dst.ip.src,
1104 ntohs(ent->dst.src_port),
1105 &ent->dst.ip.dst,
1106 ntohs(ent->dst.dst_port),
1107 ent->rateinfo.credit, ent->rateinfo.credit_cap,
1108 ent->rateinfo.cost);
1109 break;
1110 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1111 case NFPROTO_IPV6:
1112 seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n",
1113 (long)(ent->expires - jiffies)/HZ,
1114 &ent->dst.ip6.src,
1115 ntohs(ent->dst.src_port),
1116 &ent->dst.ip6.dst,
1117 ntohs(ent->dst.dst_port),
1118 ent->rateinfo.credit, ent->rateinfo.credit_cap,
1119 ent->rateinfo.cost);
1120 break;
1121 #endif
1122 default:
1123 BUG();
1124 }
1125 }
1126
1127 static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family,
1128 struct seq_file *s)
1129 {
1130 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1131
1132 spin_lock(&ent->lock);
1133 /* recalculate to show accurate numbers */
1134 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2);
1135
1136 dl_seq_print(ent, family, s);
1137
1138 spin_unlock(&ent->lock);
1139 return seq_has_overflowed(s);
1140 }
1141
1142 static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family,
1143 struct seq_file *s)
1144 {
1145 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1146
1147 spin_lock(&ent->lock);
1148 /* recalculate to show accurate numbers */
1149 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1);
1150
1151 dl_seq_print(ent, family, s);
1152
1153 spin_unlock(&ent->lock);
1154 return seq_has_overflowed(s);
1155 }
1156
1157 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
1158 struct seq_file *s)
1159 {
1160 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1161
1162 spin_lock(&ent->lock);
1163 /* recalculate to show accurate numbers */
1164 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3);
1165
1166 dl_seq_print(ent, family, s);
1167
1168 spin_unlock(&ent->lock);
1169 return seq_has_overflowed(s);
1170 }
1171
1172 static int dl_seq_show_v2(struct seq_file *s, void *v)
1173 {
1174 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1175 unsigned int *bucket = (unsigned int *)v;
1176 struct dsthash_ent *ent;
1177
1178 if (!hlist_empty(&htable->hash[*bucket])) {
1179 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1180 if (dl_seq_real_show_v2(ent, htable->family, s))
1181 return -1;
1182 }
1183 return 0;
1184 }
1185
1186 static int dl_seq_show_v1(struct seq_file *s, void *v)
1187 {
1188 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1189 unsigned int *bucket = v;
1190 struct dsthash_ent *ent;
1191
1192 if (!hlist_empty(&htable->hash[*bucket])) {
1193 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1194 if (dl_seq_real_show_v1(ent, htable->family, s))
1195 return -1;
1196 }
1197 return 0;
1198 }
1199
1200 static int dl_seq_show(struct seq_file *s, void *v)
1201 {
1202 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1203 unsigned int *bucket = v;
1204 struct dsthash_ent *ent;
1205
1206 if (!hlist_empty(&htable->hash[*bucket])) {
1207 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1208 if (dl_seq_real_show(ent, htable->family, s))
1209 return -1;
1210 }
1211 return 0;
1212 }
1213
1214 static const struct seq_operations dl_seq_ops_v1 = {
1215 .start = dl_seq_start,
1216 .next = dl_seq_next,
1217 .stop = dl_seq_stop,
1218 .show = dl_seq_show_v1
1219 };
1220
1221 static const struct seq_operations dl_seq_ops_v2 = {
1222 .start = dl_seq_start,
1223 .next = dl_seq_next,
1224 .stop = dl_seq_stop,
1225 .show = dl_seq_show_v2
1226 };
1227
1228 static const struct seq_operations dl_seq_ops = {
1229 .start = dl_seq_start,
1230 .next = dl_seq_next,
1231 .stop = dl_seq_stop,
1232 .show = dl_seq_show
1233 };
1234
1235 static int __net_init hashlimit_proc_net_init(struct net *net)
1236 {
1237 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1238
1239 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
1240 if (!hashlimit_net->ipt_hashlimit)
1241 return -ENOMEM;
1242 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1243 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
1244 if (!hashlimit_net->ip6t_hashlimit) {
1245 remove_proc_entry("ipt_hashlimit", net->proc_net);
1246 return -ENOMEM;
1247 }
1248 #endif
1249 return 0;
1250 }
1251
1252 static void __net_exit hashlimit_proc_net_exit(struct net *net)
1253 {
1254 struct xt_hashlimit_htable *hinfo;
1255 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1256
1257 /* hashlimit_net_exit() is called before hashlimit_mt_destroy().
1258 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc
1259 * entries is empty before trying to remove it.
1260 */
1261 mutex_lock(&hashlimit_mutex);
1262 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node)
1263 htable_remove_proc_entry(hinfo);
1264 hashlimit_net->ipt_hashlimit = NULL;
1265 hashlimit_net->ip6t_hashlimit = NULL;
1266 mutex_unlock(&hashlimit_mutex);
1267
1268 remove_proc_entry("ipt_hashlimit", net->proc_net);
1269 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1270 remove_proc_entry("ip6t_hashlimit", net->proc_net);
1271 #endif
1272 }
1273
1274 static int __net_init hashlimit_net_init(struct net *net)
1275 {
1276 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1277
1278 INIT_HLIST_HEAD(&hashlimit_net->htables);
1279 return hashlimit_proc_net_init(net);
1280 }
1281
1282 static void __net_exit hashlimit_net_exit(struct net *net)
1283 {
1284 hashlimit_proc_net_exit(net);
1285 }
1286
1287 static struct pernet_operations hashlimit_net_ops = {
1288 .init = hashlimit_net_init,
1289 .exit = hashlimit_net_exit,
1290 .id = &hashlimit_net_id,
1291 .size = sizeof(struct hashlimit_net),
1292 };
1293
1294 static int __init hashlimit_mt_init(void)
1295 {
1296 int err;
1297
1298 err = register_pernet_subsys(&hashlimit_net_ops);
1299 if (err < 0)
1300 return err;
1301 err = xt_register_matches(hashlimit_mt_reg,
1302 ARRAY_SIZE(hashlimit_mt_reg));
1303 if (err < 0)
1304 goto err1;
1305
1306 err = -ENOMEM;
1307 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
1308 sizeof(struct dsthash_ent), 0, 0,
1309 NULL);
1310 if (!hashlimit_cachep) {
1311 pr_warn("unable to create slab cache\n");
1312 goto err2;
1313 }
1314 return 0;
1315
1316 err2:
1317 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1318 err1:
1319 unregister_pernet_subsys(&hashlimit_net_ops);
1320 return err;
1321
1322 }
1323
1324 static void __exit hashlimit_mt_exit(void)
1325 {
1326 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1327 unregister_pernet_subsys(&hashlimit_net_ops);
1328
1329 rcu_barrier_bh();
1330 kmem_cache_destroy(hashlimit_cachep);
1331 }
1332
1333 module_init(hashlimit_mt_init);
1334 module_exit(hashlimit_mt_exit);
Linux with added FPC-III support