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/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 <laforge@netfilter.org>");
48MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
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, id: 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
121 struct hashlimit_cfg3 cfg; /* config */
122
123 /* used internally */
124 spinlock_t lock; /* lock for list_head */
125 u_int32_t rnd; /* random seed for hash */
126 unsigned int count; /* number entries in table */
127 struct delayed_work gc_work;
128
129 /* seq_file stuff */
130 struct proc_dir_entry *pde;
131 const char *name;
132 struct net *net;
133
134 struct hlist_head hash[]; /* hashtable itself */
135};
136
137static int
138cfg_copy(struct hashlimit_cfg3 *to, const void *from, int revision)
139{
140 if (revision == 1) {
141 struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from;
142
143 to->mode = cfg->mode;
144 to->avg = cfg->avg;
145 to->burst = cfg->burst;
146 to->size = cfg->size;
147 to->max = cfg->max;
148 to->gc_interval = cfg->gc_interval;
149 to->expire = cfg->expire;
150 to->srcmask = cfg->srcmask;
151 to->dstmask = cfg->dstmask;
152 } else if (revision == 2) {
153 struct hashlimit_cfg2 *cfg = (struct hashlimit_cfg2 *)from;
154
155 to->mode = cfg->mode;
156 to->avg = cfg->avg;
157 to->burst = cfg->burst;
158 to->size = cfg->size;
159 to->max = cfg->max;
160 to->gc_interval = cfg->gc_interval;
161 to->expire = cfg->expire;
162 to->srcmask = cfg->srcmask;
163 to->dstmask = cfg->dstmask;
164 } else if (revision == 3) {
165 memcpy(to, from, sizeof(struct hashlimit_cfg3));
166 } else {
167 return -EINVAL;
168 }
169
170 return 0;
171}
172
173static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */
174static struct kmem_cache *hashlimit_cachep __read_mostly;
175
176static inline bool dst_cmp(const struct dsthash_ent *ent,
177 const struct dsthash_dst *b)
178{
179 return !memcmp(p: &ent->dst, q: b, size: sizeof(ent->dst));
180}
181
182static u_int32_t
183hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
184{
185 u_int32_t hash = jhash2(k: (const u32 *)dst,
186 length: sizeof(*dst)/sizeof(u32),
187 initval: ht->rnd);
188 /*
189 * Instead of returning hash % ht->cfg.size (implying a divide)
190 * we return the high 32 bits of the (hash * ht->cfg.size) that will
191 * give results between [0 and cfg.size-1] and same hash distribution,
192 * but using a multiply, less expensive than a divide
193 */
194 return reciprocal_scale(val: hash, ep_ro: ht->cfg.size);
195}
196
197static struct dsthash_ent *
198dsthash_find(const struct xt_hashlimit_htable *ht,
199 const struct dsthash_dst *dst)
200{
201 struct dsthash_ent *ent;
202 u_int32_t hash = hash_dst(ht, dst);
203
204 if (!hlist_empty(h: &ht->hash[hash])) {
205 hlist_for_each_entry_rcu(ent, &ht->hash[hash], node)
206 if (dst_cmp(ent, b: dst)) {
207 spin_lock(lock: &ent->lock);
208 return ent;
209 }
210 }
211 return NULL;
212}
213
214/* allocate dsthash_ent, initialize dst, put in htable and lock it */
215static struct dsthash_ent *
216dsthash_alloc_init(struct xt_hashlimit_htable *ht,
217 const struct dsthash_dst *dst, bool *race)
218{
219 struct dsthash_ent *ent;
220
221 spin_lock(lock: &ht->lock);
222
223 /* Two or more packets may race to create the same entry in the
224 * hashtable, double check if this packet lost race.
225 */
226 ent = dsthash_find(ht, dst);
227 if (ent != NULL) {
228 spin_unlock(lock: &ht->lock);
229 *race = true;
230 return ent;
231 }
232
233 /* initialize hash with random val at the time we allocate
234 * the first hashtable entry */
235 if (unlikely(!ht->rnd_initialized)) {
236 get_random_bytes(buf: &ht->rnd, len: sizeof(ht->rnd));
237 ht->rnd_initialized = true;
238 }
239
240 if (ht->cfg.max && ht->count >= ht->cfg.max) {
241 /* FIXME: do something. question is what.. */
242 net_err_ratelimited("max count of %u reached\n", ht->cfg.max);
243 ent = NULL;
244 } else
245 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
246 if (ent) {
247 memcpy(&ent->dst, dst, sizeof(ent->dst));
248 spin_lock_init(&ent->lock);
249
250 spin_lock(lock: &ent->lock);
251 hlist_add_head_rcu(n: &ent->node, h: &ht->hash[hash_dst(ht, dst)]);
252 ht->count++;
253 }
254 spin_unlock(lock: &ht->lock);
255 return ent;
256}
257
258static void dsthash_free_rcu(struct rcu_head *head)
259{
260 struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
261
262 kmem_cache_free(s: hashlimit_cachep, objp: ent);
263}
264
265static inline void
266dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
267{
268 hlist_del_rcu(n: &ent->node);
269 call_rcu(head: &ent->rcu, func: dsthash_free_rcu);
270 ht->count--;
271}
272static void htable_gc(struct work_struct *work);
273
274static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg,
275 const char *name, u_int8_t family,
276 struct xt_hashlimit_htable **out_hinfo,
277 int revision)
278{
279 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
280 struct xt_hashlimit_htable *hinfo;
281 const struct seq_operations *ops;
282 unsigned int size, i;
283 unsigned long nr_pages = totalram_pages();
284 int ret;
285
286 if (cfg->size) {
287 size = cfg->size;
288 } else {
289 size = (nr_pages << PAGE_SHIFT) / 16384 /
290 sizeof(struct hlist_head);
291 if (nr_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
292 size = 8192;
293 if (size < 16)
294 size = 16;
295 }
296 hinfo = kvmalloc(struct_size(hinfo, hash, size), GFP_KERNEL);
297 if (hinfo == NULL)
298 return -ENOMEM;
299 *out_hinfo = hinfo;
300
301 /* copy match config into hashtable config */
302 ret = cfg_copy(to: &hinfo->cfg, from: (void *)cfg, revision: 3);
303 if (ret) {
304 kvfree(addr: hinfo);
305 return ret;
306 }
307
308 hinfo->cfg.size = size;
309 if (hinfo->cfg.max == 0)
310 hinfo->cfg.max = 8 * hinfo->cfg.size;
311 else if (hinfo->cfg.max < hinfo->cfg.size)
312 hinfo->cfg.max = hinfo->cfg.size;
313
314 for (i = 0; i < hinfo->cfg.size; i++)
315 INIT_HLIST_HEAD(&hinfo->hash[i]);
316
317 refcount_set(r: &hinfo->use, n: 1);
318 hinfo->count = 0;
319 hinfo->family = family;
320 hinfo->rnd_initialized = false;
321 hinfo->name = kstrdup(s: name, GFP_KERNEL);
322 if (!hinfo->name) {
323 kvfree(addr: hinfo);
324 return -ENOMEM;
325 }
326 spin_lock_init(&hinfo->lock);
327
328 switch (revision) {
329 case 1:
330 ops = &dl_seq_ops_v1;
331 break;
332 case 2:
333 ops = &dl_seq_ops_v2;
334 break;
335 default:
336 ops = &dl_seq_ops;
337 }
338
339 hinfo->pde = proc_create_seq_data(name, 0,
340 (family == NFPROTO_IPV4) ?
341 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
342 ops, hinfo);
343 if (hinfo->pde == NULL) {
344 kfree(objp: hinfo->name);
345 kvfree(addr: hinfo);
346 return -ENOMEM;
347 }
348 hinfo->net = net;
349
350 INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc);
351 queue_delayed_work(wq: system_power_efficient_wq, dwork: &hinfo->gc_work,
352 delay: msecs_to_jiffies(m: hinfo->cfg.gc_interval));
353
354 hlist_add_head(n: &hinfo->node, h: &hashlimit_net->htables);
355
356 return 0;
357}
358
359static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, bool select_all)
360{
361 unsigned int i;
362
363 for (i = 0; i < ht->cfg.size; i++) {
364 struct hlist_head *head = &ht->hash[i];
365 struct dsthash_ent *dh;
366 struct hlist_node *n;
367
368 if (hlist_empty(h: head))
369 continue;
370
371 spin_lock_bh(lock: &ht->lock);
372 hlist_for_each_entry_safe(dh, n, head, node) {
373 if (time_after_eq(jiffies, dh->expires) || select_all)
374 dsthash_free(ht, ent: dh);
375 }
376 spin_unlock_bh(lock: &ht->lock);
377 cond_resched();
378 }
379}
380
381static void htable_gc(struct work_struct *work)
382{
383 struct xt_hashlimit_htable *ht;
384
385 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
386
387 htable_selective_cleanup(ht, select_all: false);
388
389 queue_delayed_work(wq: system_power_efficient_wq,
390 dwork: &ht->gc_work, delay: msecs_to_jiffies(m: ht->cfg.gc_interval));
391}
392
393static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
394{
395 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net: hinfo->net);
396 struct proc_dir_entry *parent;
397
398 if (hinfo->family == NFPROTO_IPV4)
399 parent = hashlimit_net->ipt_hashlimit;
400 else
401 parent = hashlimit_net->ip6t_hashlimit;
402
403 if (parent != NULL)
404 remove_proc_entry(hinfo->name, parent);
405}
406
407static struct xt_hashlimit_htable *htable_find_get(struct net *net,
408 const char *name,
409 u_int8_t family)
410{
411 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
412 struct xt_hashlimit_htable *hinfo;
413
414 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
415 if (!strcmp(name, hinfo->name) &&
416 hinfo->family == family) {
417 refcount_inc(r: &hinfo->use);
418 return hinfo;
419 }
420 }
421 return NULL;
422}
423
424static void htable_put(struct xt_hashlimit_htable *hinfo)
425{
426 if (refcount_dec_and_mutex_lock(r: &hinfo->use, lock: &hashlimit_mutex)) {
427 hlist_del(n: &hinfo->node);
428 htable_remove_proc_entry(hinfo);
429 mutex_unlock(lock: &hashlimit_mutex);
430
431 cancel_delayed_work_sync(dwork: &hinfo->gc_work);
432 htable_selective_cleanup(ht: hinfo, select_all: true);
433 kfree(objp: hinfo->name);
434 kvfree(addr: hinfo);
435 }
436}
437
438/* The algorithm used is the Simple Token Bucket Filter (TBF)
439 * see net/sched/sch_tbf.c in the linux source tree
440 */
441
442/* Rusty: This is my (non-mathematically-inclined) understanding of
443 this algorithm. The `average rate' in jiffies becomes your initial
444 amount of credit `credit' and the most credit you can ever have
445 `credit_cap'. The `peak rate' becomes the cost of passing the
446 test, `cost'.
447
448 `prev' tracks the last packet hit: you gain one credit per jiffy.
449 If you get credit balance more than this, the extra credit is
450 discarded. Every time the match passes, you lose `cost' credits;
451 if you don't have that many, the test fails.
452
453 See Alexey's formal explanation in net/sched/sch_tbf.c.
454
455 To get the maximum range, we multiply by this factor (ie. you get N
456 credits per jiffy). We want to allow a rate as low as 1 per day
457 (slowest userspace tool allows), which means
458 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
459*/
460#define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24))
461#define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24))
462
463/* Repeated shift and or gives us all 1s, final shift and add 1 gives
464 * us the power of 2 below the theoretical max, so GCC simply does a
465 * shift. */
466#define _POW2_BELOW2(x) ((x)|((x)>>1))
467#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
468#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
469#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
470#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
471#define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32))
472#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
473#define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1)
474
475#define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ)
476#define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1)
477
478/* in byte mode, the lowest possible rate is one packet/second.
479 * credit_cap is used as a counter that tells us how many times we can
480 * refill the "credits available" counter when it becomes empty.
481 */
482#define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
483#define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
484
485static u32 xt_hashlimit_len_to_chunks(u32 len)
486{
487 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
488}
489
490/* Precision saver. */
491static u64 user2credits(u64 user, int revision)
492{
493 u64 scale = (revision == 1) ?
494 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
495 u64 cpj = (revision == 1) ?
496 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
497
498 /* Avoid overflow: divide the constant operands first */
499 if (scale >= HZ * cpj)
500 return div64_u64(dividend: user, divisor: div64_u64(dividend: scale, HZ * cpj));
501
502 return user * div64_u64(HZ * cpj, divisor: scale);
503}
504
505static u32 user2credits_byte(u32 user)
506{
507 u64 us = user;
508 us *= HZ * CREDITS_PER_JIFFY_BYTES;
509 return (u32) (us >> 32);
510}
511
512static u64 user2rate(u64 user)
513{
514 if (user != 0) {
515 return div64_u64(XT_HASHLIMIT_SCALE_v2, divisor: user);
516 } else {
517 pr_info_ratelimited("invalid rate from userspace: %llu\n",
518 user);
519 return 0;
520 }
521}
522
523static u64 user2rate_bytes(u32 user)
524{
525 u64 r;
526
527 r = user ? U32_MAX / user : U32_MAX;
528 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT;
529}
530
531static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now,
532 u32 mode, int revision)
533{
534 unsigned long delta = now - dh->rateinfo.prev;
535 u64 cap, cpj;
536
537 if (delta == 0)
538 return;
539
540 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) {
541 u64 interval = dh->rateinfo.interval * HZ;
542
543 if (delta < interval)
544 return;
545
546 dh->rateinfo.prev = now;
547 dh->rateinfo.prev_window =
548 ((dh->rateinfo.current_rate * interval) >
549 (delta * dh->rateinfo.rate));
550 dh->rateinfo.current_rate = 0;
551
552 return;
553 }
554
555 dh->rateinfo.prev = now;
556
557 if (mode & XT_HASHLIMIT_BYTES) {
558 u64 tmp = dh->rateinfo.credit;
559 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
560 cap = CREDITS_PER_JIFFY_BYTES * HZ;
561 if (tmp >= dh->rateinfo.credit) {/* overflow */
562 dh->rateinfo.credit = cap;
563 return;
564 }
565 } else {
566 cpj = (revision == 1) ?
567 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
568 dh->rateinfo.credit += delta * cpj;
569 cap = dh->rateinfo.credit_cap;
570 }
571 if (dh->rateinfo.credit > cap)
572 dh->rateinfo.credit = cap;
573}
574
575static void rateinfo_init(struct dsthash_ent *dh,
576 struct xt_hashlimit_htable *hinfo, int revision)
577{
578 dh->rateinfo.prev = jiffies;
579 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) {
580 dh->rateinfo.prev_window = 0;
581 dh->rateinfo.current_rate = 0;
582 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
583 dh->rateinfo.rate =
584 user2rate_bytes(user: (u32)hinfo->cfg.avg);
585 if (hinfo->cfg.burst)
586 dh->rateinfo.burst =
587 hinfo->cfg.burst * dh->rateinfo.rate;
588 else
589 dh->rateinfo.burst = dh->rateinfo.rate;
590 } else {
591 dh->rateinfo.rate = user2rate(user: hinfo->cfg.avg);
592 dh->rateinfo.burst =
593 hinfo->cfg.burst + dh->rateinfo.rate;
594 }
595 dh->rateinfo.interval = hinfo->cfg.interval;
596 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
597 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
598 dh->rateinfo.cost = user2credits_byte(user: hinfo->cfg.avg);
599 dh->rateinfo.credit_cap = hinfo->cfg.burst;
600 } else {
601 dh->rateinfo.credit = user2credits(user: hinfo->cfg.avg *
602 hinfo->cfg.burst, revision);
603 dh->rateinfo.cost = user2credits(user: hinfo->cfg.avg, revision);
604 dh->rateinfo.credit_cap = dh->rateinfo.credit;
605 }
606}
607
608static inline __be32 maskl(__be32 a, unsigned int l)
609{
610 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
611}
612
613#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
614static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
615{
616 switch (p) {
617 case 0 ... 31:
618 i[0] = maskl(a: i[0], l: p);
619 i[1] = i[2] = i[3] = 0;
620 break;
621 case 32 ... 63:
622 i[1] = maskl(a: i[1], l: p - 32);
623 i[2] = i[3] = 0;
624 break;
625 case 64 ... 95:
626 i[2] = maskl(a: i[2], l: p - 64);
627 i[3] = 0;
628 break;
629 case 96 ... 127:
630 i[3] = maskl(a: i[3], l: p - 96);
631 break;
632 case 128:
633 break;
634 }
635}
636#endif
637
638static int
639hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
640 struct dsthash_dst *dst,
641 const struct sk_buff *skb, unsigned int protoff)
642{
643 __be16 _ports[2], *ports;
644 u8 nexthdr;
645 int poff;
646
647 memset(dst, 0, sizeof(*dst));
648
649 switch (hinfo->family) {
650 case NFPROTO_IPV4:
651 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
652 dst->ip.dst = maskl(a: ip_hdr(skb)->daddr,
653 l: hinfo->cfg.dstmask);
654 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
655 dst->ip.src = maskl(a: ip_hdr(skb)->saddr,
656 l: hinfo->cfg.srcmask);
657
658 if (!(hinfo->cfg.mode &
659 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
660 return 0;
661 nexthdr = ip_hdr(skb)->protocol;
662 break;
663#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
664 case NFPROTO_IPV6:
665 {
666 __be16 frag_off;
667
668 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
669 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
670 sizeof(dst->ip6.dst));
671 hashlimit_ipv6_mask(i: dst->ip6.dst, p: hinfo->cfg.dstmask);
672 }
673 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
674 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
675 sizeof(dst->ip6.src));
676 hashlimit_ipv6_mask(i: dst->ip6.src, p: hinfo->cfg.srcmask);
677 }
678
679 if (!(hinfo->cfg.mode &
680 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
681 return 0;
682 nexthdr = ipv6_hdr(skb)->nexthdr;
683 protoff = ipv6_skip_exthdr(skb, start: sizeof(struct ipv6hdr), nexthdrp: &nexthdr, frag_offp: &frag_off);
684 if ((int)protoff < 0)
685 return -1;
686 break;
687 }
688#endif
689 default:
690 BUG();
691 return 0;
692 }
693
694 poff = proto_ports_offset(proto: nexthdr);
695 if (poff >= 0) {
696 ports = skb_header_pointer(skb, offset: protoff + poff, len: sizeof(_ports),
697 buffer: &_ports);
698 } else {
699 _ports[0] = _ports[1] = 0;
700 ports = _ports;
701 }
702 if (!ports)
703 return -1;
704 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
705 dst->src_port = ports[0];
706 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
707 dst->dst_port = ports[1];
708 return 0;
709}
710
711static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
712{
713 u64 tmp = xt_hashlimit_len_to_chunks(len);
714 tmp = tmp * dh->rateinfo.cost;
715
716 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
717 tmp = CREDITS_PER_JIFFY_BYTES * HZ;
718
719 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
720 dh->rateinfo.credit_cap--;
721 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
722 }
723 return (u32) tmp;
724}
725
726static bool
727hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
728 struct xt_hashlimit_htable *hinfo,
729 const struct hashlimit_cfg3 *cfg, int revision)
730{
731 unsigned long now = jiffies;
732 struct dsthash_ent *dh;
733 struct dsthash_dst dst;
734 bool race = false;
735 u64 cost;
736
737 if (hashlimit_init_dst(hinfo, dst: &dst, skb, protoff: par->thoff) < 0)
738 goto hotdrop;
739
740 local_bh_disable();
741 dh = dsthash_find(ht: hinfo, dst: &dst);
742 if (dh == NULL) {
743 dh = dsthash_alloc_init(ht: hinfo, dst: &dst, race: &race);
744 if (dh == NULL) {
745 local_bh_enable();
746 goto hotdrop;
747 } else if (race) {
748 /* Already got an entry, update expiration timeout */
749 dh->expires = now + msecs_to_jiffies(m: hinfo->cfg.expire);
750 rateinfo_recalc(dh, now, mode: hinfo->cfg.mode, revision);
751 } else {
752 dh->expires = jiffies + msecs_to_jiffies(m: hinfo->cfg.expire);
753 rateinfo_init(dh, hinfo, revision);
754 }
755 } else {
756 /* update expiration timeout */
757 dh->expires = now + msecs_to_jiffies(m: hinfo->cfg.expire);
758 rateinfo_recalc(dh, now, mode: hinfo->cfg.mode, revision);
759 }
760
761 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
762 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1;
763 dh->rateinfo.current_rate += cost;
764
765 if (!dh->rateinfo.prev_window &&
766 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
767 spin_unlock(lock: &dh->lock);
768 local_bh_enable();
769 return !(cfg->mode & XT_HASHLIMIT_INVERT);
770 } else {
771 goto overlimit;
772 }
773 }
774
775 if (cfg->mode & XT_HASHLIMIT_BYTES)
776 cost = hashlimit_byte_cost(len: skb->len, dh);
777 else
778 cost = dh->rateinfo.cost;
779
780 if (dh->rateinfo.credit >= cost) {
781 /* below the limit */
782 dh->rateinfo.credit -= cost;
783 spin_unlock(lock: &dh->lock);
784 local_bh_enable();
785 return !(cfg->mode & XT_HASHLIMIT_INVERT);
786 }
787
788overlimit:
789 spin_unlock(lock: &dh->lock);
790 local_bh_enable();
791 /* default match is underlimit - so over the limit, we need to invert */
792 return cfg->mode & XT_HASHLIMIT_INVERT;
793
794 hotdrop:
795 par->hotdrop = true;
796 return false;
797}
798
799static bool
800hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
801{
802 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
803 struct xt_hashlimit_htable *hinfo = info->hinfo;
804 struct hashlimit_cfg3 cfg = {};
805 int ret;
806
807 ret = cfg_copy(to: &cfg, from: (void *)&info->cfg, revision: 1);
808 if (ret)
809 return ret;
810
811 return hashlimit_mt_common(skb, par, hinfo, cfg: &cfg, revision: 1);
812}
813
814static bool
815hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
816{
817 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
818 struct xt_hashlimit_htable *hinfo = info->hinfo;
819 struct hashlimit_cfg3 cfg = {};
820 int ret;
821
822 ret = cfg_copy(to: &cfg, from: (void *)&info->cfg, revision: 2);
823 if (ret)
824 return ret;
825
826 return hashlimit_mt_common(skb, par, hinfo, cfg: &cfg, revision: 2);
827}
828
829static bool
830hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
831{
832 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
833 struct xt_hashlimit_htable *hinfo = info->hinfo;
834
835 return hashlimit_mt_common(skb, par, hinfo, cfg: &info->cfg, revision: 3);
836}
837
838#define HASHLIMIT_MAX_SIZE 1048576
839
840static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
841 struct xt_hashlimit_htable **hinfo,
842 struct hashlimit_cfg3 *cfg,
843 const char *name, int revision)
844{
845 struct net *net = par->net;
846 int ret;
847
848 if (cfg->gc_interval == 0 || cfg->expire == 0)
849 return -EINVAL;
850 if (cfg->size > HASHLIMIT_MAX_SIZE) {
851 cfg->size = HASHLIMIT_MAX_SIZE;
852 pr_info_ratelimited("size too large, truncated to %u\n", cfg->size);
853 }
854 if (cfg->max > HASHLIMIT_MAX_SIZE) {
855 cfg->max = HASHLIMIT_MAX_SIZE;
856 pr_info_ratelimited("max too large, truncated to %u\n", cfg->max);
857 }
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(user: 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(user: cfg->avg * cfg->burst, revision) <
891 user2credits(user: 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, family: par->family);
899 if (*hinfo == NULL) {
900 ret = htable_create(net, cfg, name, family: par->family,
901 out_hinfo: hinfo, revision);
902 if (ret < 0) {
903 mutex_unlock(lock: &hashlimit_mutex);
904 return ret;
905 }
906 }
907 mutex_unlock(lock: &hashlimit_mutex);
908
909 return 0;
910}
911
912static 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(name: info->name, size: sizeof(info->name));
919 if (ret)
920 return ret;
921
922 ret = cfg_copy(to: &cfg, from: (void *)&info->cfg, revision: 1);
923 if (ret)
924 return ret;
925
926 return hashlimit_mt_check_common(par, hinfo: &info->hinfo,
927 cfg: &cfg, name: info->name, revision: 1);
928}
929
930static 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(name: info->name, size: sizeof(info->name));
937 if (ret)
938 return ret;
939
940 ret = cfg_copy(to: &cfg, from: (void *)&info->cfg, revision: 2);
941 if (ret)
942 return ret;
943
944 return hashlimit_mt_check_common(par, hinfo: &info->hinfo,
945 cfg: &cfg, name: info->name, revision: 2);
946}
947
948static 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(name: info->name, size: sizeof(info->name));
954 if (ret)
955 return ret;
956
957 return hashlimit_mt_check_common(par, hinfo: &info->hinfo, cfg: &info->cfg,
958 name: info->name, revision: 3);
959}
960
961static 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(hinfo: info->hinfo);
966}
967
968static 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(hinfo: info->hinfo);
973}
974
975static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
976{
977 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
978
979 htable_put(hinfo: info->hinfo);
980}
981
982static 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 */
1054static void *dl_seq_start(struct seq_file *s, loff_t *pos)
1055 __acquires(htable->lock)
1056{
1057 struct xt_hashlimit_htable *htable = pde_data(inode: file_inode(f: s->file));
1058 unsigned int *bucket;
1059
1060 spin_lock_bh(lock: &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(error: -ENOMEM);
1067
1068 *bucket = *pos;
1069 return bucket;
1070}
1071
1072static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
1073{
1074 struct xt_hashlimit_htable *htable = pde_data(inode: file_inode(f: s->file));
1075 unsigned int *bucket = v;
1076
1077 *pos = ++(*bucket);
1078 if (*pos >= htable->cfg.size) {
1079 kfree(objp: v);
1080 return NULL;
1081 }
1082 return bucket;
1083}
1084
1085static void dl_seq_stop(struct seq_file *s, void *v)
1086 __releases(htable->lock)
1087{
1088 struct xt_hashlimit_htable *htable = pde_data(inode: file_inode(f: s->file));
1089 unsigned int *bucket = v;
1090
1091 if (!IS_ERR(ptr: bucket))
1092 kfree(objp: bucket);
1093 spin_unlock_bh(lock: &htable->lock);
1094}
1095
1096static 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(m: s, fmt: "%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(m: s, fmt: "%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
1127static 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(inode: file_inode(f: s->file));
1131
1132 spin_lock(lock: &ent->lock);
1133 /* recalculate to show accurate numbers */
1134 rateinfo_recalc(dh: ent, now: jiffies, mode: ht->cfg.mode, revision: 2);
1135
1136 dl_seq_print(ent, family, s);
1137
1138 spin_unlock(lock: &ent->lock);
1139 return seq_has_overflowed(m: s);
1140}
1141
1142static 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(inode: file_inode(f: s->file));
1146
1147 spin_lock(lock: &ent->lock);
1148 /* recalculate to show accurate numbers */
1149 rateinfo_recalc(dh: ent, now: jiffies, mode: ht->cfg.mode, revision: 1);
1150
1151 dl_seq_print(ent, family, s);
1152
1153 spin_unlock(lock: &ent->lock);
1154 return seq_has_overflowed(m: s);
1155}
1156
1157static 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(inode: file_inode(f: s->file));
1161
1162 spin_lock(lock: &ent->lock);
1163 /* recalculate to show accurate numbers */
1164 rateinfo_recalc(dh: ent, now: jiffies, mode: ht->cfg.mode, revision: 3);
1165
1166 dl_seq_print(ent, family, s);
1167
1168 spin_unlock(lock: &ent->lock);
1169 return seq_has_overflowed(m: s);
1170}
1171
1172static int dl_seq_show_v2(struct seq_file *s, void *v)
1173{
1174 struct xt_hashlimit_htable *htable = pde_data(inode: file_inode(f: s->file));
1175 unsigned int *bucket = (unsigned int *)v;
1176 struct dsthash_ent *ent;
1177
1178 if (!hlist_empty(h: &htable->hash[*bucket])) {
1179 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1180 if (dl_seq_real_show_v2(ent, family: htable->family, s))
1181 return -1;
1182 }
1183 return 0;
1184}
1185
1186static int dl_seq_show_v1(struct seq_file *s, void *v)
1187{
1188 struct xt_hashlimit_htable *htable = pde_data(inode: file_inode(f: s->file));
1189 unsigned int *bucket = v;
1190 struct dsthash_ent *ent;
1191
1192 if (!hlist_empty(h: &htable->hash[*bucket])) {
1193 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1194 if (dl_seq_real_show_v1(ent, family: htable->family, s))
1195 return -1;
1196 }
1197 return 0;
1198}
1199
1200static int dl_seq_show(struct seq_file *s, void *v)
1201{
1202 struct xt_hashlimit_htable *htable = pde_data(inode: file_inode(f: s->file));
1203 unsigned int *bucket = v;
1204 struct dsthash_ent *ent;
1205
1206 if (!hlist_empty(h: &htable->hash[*bucket])) {
1207 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1208 if (dl_seq_real_show(ent, family: htable->family, s))
1209 return -1;
1210 }
1211 return 0;
1212}
1213
1214static 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
1221static 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
1228static 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
1235static 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
1252static 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(lock: &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
1274static 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
1282static void __net_exit hashlimit_net_exit(struct net *net)
1283{
1284 hashlimit_proc_net_exit(net);
1285}
1286
1287static 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
1294static 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(match: 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
1316err2:
1317 xt_unregister_matches(match: hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1318err1:
1319 unregister_pernet_subsys(&hashlimit_net_ops);
1320 return err;
1321
1322}
1323
1324static void __exit hashlimit_mt_exit(void)
1325{
1326 xt_unregister_matches(match: hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1327 unregister_pernet_subsys(&hashlimit_net_ops);
1328
1329 rcu_barrier();
1330 kmem_cache_destroy(s: hashlimit_cachep);
1331}
1332
1333module_init(hashlimit_mt_init);
1334module_exit(hashlimit_mt_exit);
1335

source code of linux/net/netfilter/xt_hashlimit.c