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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 <laforge@netfilter.org>
7 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
8 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
9 *
10 * Development of this code was funded by Astaro AG, http://www.astaro.com/
11 */
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13#include <linux/module.h>
14#include <linux/spinlock.h>
15#include <linux/random.h>
16#include <linux/jhash.h>
17#include <linux/slab.h>
18#include <linux/vmalloc.h>
19#include <linux/proc_fs.h>
20#include <linux/seq_file.h>
21#include <linux/list.h>
22#include <linux/skbuff.h>
23#include <linux/mm.h>
24#include <linux/in.h>
25#include <linux/ip.h>
26#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
27#include <linux/ipv6.h>
28#include <net/ipv6.h>
29#endif
30
31#include <net/net_namespace.h>
32#include <net/netns/generic.h>
33
34#include <linux/netfilter/x_tables.h>
35#include <linux/netfilter_ipv4/ip_tables.h>
36#include <linux/netfilter_ipv6/ip6_tables.h>
37#include <linux/mutex.h>
38#include <linux/kernel.h>
39#include <linux/refcount.h>
40#include <uapi/linux/netfilter/xt_hashlimit.h>
41
42#define XT_HASHLIMIT_ALL (XT_HASHLIMIT_HASH_DIP | XT_HASHLIMIT_HASH_DPT | \
43 XT_HASHLIMIT_HASH_SIP | XT_HASHLIMIT_HASH_SPT | \
44 XT_HASHLIMIT_INVERT | XT_HASHLIMIT_BYTES |\
45 XT_HASHLIMIT_RATE_MATCH)
46
47MODULE_LICENSE("GPL");
48MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
49MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
50MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
51MODULE_ALIAS("ipt_hashlimit");
52MODULE_ALIAS("ip6t_hashlimit");
53
54struct hashlimit_net {
55 struct hlist_head htables;
56 struct proc_dir_entry *ipt_hashlimit;
57 struct proc_dir_entry *ip6t_hashlimit;
58};
59
60static unsigned int hashlimit_net_id;
61static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
62{
63 return net_generic(net, hashlimit_net_id);
64}
65
66/* need to declare this at the top */
67static const struct seq_operations dl_seq_ops_v2;
68static const struct seq_operations dl_seq_ops_v1;
69static const struct seq_operations dl_seq_ops;
70
71/* hash table crap */
72struct dsthash_dst {
73 union {
74 struct {
75 __be32 src;
76 __be32 dst;
77 } ip;
78#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
79 struct {
80 __be32 src[4];
81 __be32 dst[4];
82 } ip6;
83#endif
84 };
85 __be16 src_port;
86 __be16 dst_port;
87};
88
89struct dsthash_ent {
90 /* static / read-only parts in the beginning */
91 struct hlist_node node;
92 struct dsthash_dst dst;
93
94 /* modified structure members in the end */
95 spinlock_t lock;
96 unsigned long expires; /* precalculated expiry time */
97 struct {
98 unsigned long prev; /* last modification */
99 union {
100 struct {
101 u_int64_t credit;
102 u_int64_t credit_cap;
103 u_int64_t cost;
104 };
105 struct {
106 u_int32_t interval, prev_window;
107 u_int64_t current_rate;
108 u_int64_t rate;
109 int64_t burst;
110 };
111 };
112 } rateinfo;
113 struct rcu_head rcu;
114};
115
116struct xt_hashlimit_htable {
117 struct hlist_node node; /* global list of all htables */
118 refcount_t use;
119 u_int8_t family;
120 bool rnd_initialized;
121
122 struct hashlimit_cfg3 cfg; /* config */
123
124 /* used internally */
125 spinlock_t lock; /* lock for list_head */
126 u_int32_t rnd; /* random seed for hash */
127 unsigned int count; /* number entries in table */
128 struct delayed_work gc_work;
129
130 /* seq_file stuff */
131 struct proc_dir_entry *pde;
132 const char *name;
133 struct net *net;
134
135 struct hlist_head hash[]; /* hashtable itself */
136};
137
138static int
139cfg_copy(struct hashlimit_cfg3 *to, const void *from, int revision)
140{
141 if (revision == 1) {
142 struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from;
143
144 to->mode = cfg->mode;
145 to->avg = cfg->avg;
146 to->burst = cfg->burst;
147 to->size = cfg->size;
148 to->max = cfg->max;
149 to->gc_interval = cfg->gc_interval;
150 to->expire = cfg->expire;
151 to->srcmask = cfg->srcmask;
152 to->dstmask = cfg->dstmask;
153 } else if (revision == 2) {
154 struct hashlimit_cfg2 *cfg = (struct hashlimit_cfg2 *)from;
155
156 to->mode = cfg->mode;
157 to->avg = cfg->avg;
158 to->burst = cfg->burst;
159 to->size = cfg->size;
160 to->max = cfg->max;
161 to->gc_interval = cfg->gc_interval;
162 to->expire = cfg->expire;
163 to->srcmask = cfg->srcmask;
164 to->dstmask = cfg->dstmask;
165 } else if (revision == 3) {
166 memcpy(to, from, sizeof(struct hashlimit_cfg3));
167 } else {
168 return -EINVAL;
169 }
170
171 return 0;
172}
173
174static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */
175static struct kmem_cache *hashlimit_cachep __read_mostly;
176
177static inline bool dst_cmp(const struct dsthash_ent *ent,
178 const struct dsthash_dst *b)
179{
180 return !memcmp(&ent->dst, b, sizeof(ent->dst));
181}
182
183static u_int32_t
184hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
185{
186 u_int32_t hash = jhash2((const u32 *)dst,
187 sizeof(*dst)/sizeof(u32),
188 ht->rnd);
189 /*
190 * Instead of returning hash % ht->cfg.size (implying a divide)
191 * we return the high 32 bits of the (hash * ht->cfg.size) that will
192 * give results between [0 and cfg.size-1] and same hash distribution,
193 * but using a multiply, less expensive than a divide
194 */
195 return reciprocal_scale(hash, ht->cfg.size);
196}
197
198static struct dsthash_ent *
199dsthash_find(const struct xt_hashlimit_htable *ht,
200 const struct dsthash_dst *dst)
201{
202 struct dsthash_ent *ent;
203 u_int32_t hash = hash_dst(ht, dst);
204
205 if (!hlist_empty(&ht->hash[hash])) {
206 hlist_for_each_entry_rcu(ent, &ht->hash[hash], node)
207 if (dst_cmp(ent, dst)) {
208 spin_lock(&ent->lock);
209 return ent;
210 }
211 }
212 return NULL;
213}
214
215/* allocate dsthash_ent, initialize dst, put in htable and lock it */
216static struct dsthash_ent *
217dsthash_alloc_init(struct xt_hashlimit_htable *ht,
218 const struct dsthash_dst *dst, bool *race)
219{
220 struct dsthash_ent *ent;
221
222 spin_lock(&ht->lock);
223
224 /* Two or more packets may race to create the same entry in the
225 * hashtable, double check if this packet lost race.
226 */
227 ent = dsthash_find(ht, dst);
228 if (ent != NULL) {
229 spin_unlock(&ht->lock);
230 *race = true;
231 return ent;
232 }
233
234 /* initialize hash with random val at the time we allocate
235 * the first hashtable entry */
236 if (unlikely(!ht->rnd_initialized)) {
237 get_random_bytes(&ht->rnd, sizeof(ht->rnd));
238 ht->rnd_initialized = true;
239 }
240
241 if (ht->cfg.max && ht->count >= ht->cfg.max) {
242 /* FIXME: do something. question is what.. */
243 net_err_ratelimited("max count of %u reached\n", ht->cfg.max);
244 ent = NULL;
245 } else
246 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
247 if (ent) {
248 memcpy(&ent->dst, dst, sizeof(ent->dst));
249 spin_lock_init(&ent->lock);
250
251 spin_lock(&ent->lock);
252 hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]);
253 ht->count++;
254 }
255 spin_unlock(&ht->lock);
256 return ent;
257}
258
259static void dsthash_free_rcu(struct rcu_head *head)
260{
261 struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
262
263 kmem_cache_free(hashlimit_cachep, ent);
264}
265
266static inline void
267dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
268{
269 hlist_del_rcu(&ent->node);
270 call_rcu(&ent->rcu, dsthash_free_rcu);
271 ht->count--;
272}
273static void htable_gc(struct work_struct *work);
274
275static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg,
276 const char *name, u_int8_t family,
277 struct xt_hashlimit_htable **out_hinfo,
278 int revision)
279{
280 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
281 struct xt_hashlimit_htable *hinfo;
282 const struct seq_operations *ops;
283 unsigned int size, i;
284 unsigned long nr_pages = totalram_pages();
285 int ret;
286
287 if (cfg->size) {
288 size = cfg->size;
289 } else {
290 size = (nr_pages << PAGE_SHIFT) / 16384 /
291 sizeof(struct hlist_head);
292 if (nr_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
293 size = 8192;
294 if (size < 16)
295 size = 16;
296 }
297 /* FIXME: don't use vmalloc() here or anywhere else -HW */
298 hinfo = vmalloc(struct_size(hinfo, hash, size));
299 if (hinfo == NULL)
300 return -ENOMEM;
301 *out_hinfo = hinfo;
302
303 /* copy match config into hashtable config */
304 ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3);
305 if (ret) {
306 vfree(hinfo);
307 return ret;
308 }
309
310 hinfo->cfg.size = size;
311 if (hinfo->cfg.max == 0)
312 hinfo->cfg.max = 8 * hinfo->cfg.size;
313 else if (hinfo->cfg.max < hinfo->cfg.size)
314 hinfo->cfg.max = hinfo->cfg.size;
315
316 for (i = 0; i < hinfo->cfg.size; i++)
317 INIT_HLIST_HEAD(&hinfo->hash[i]);
318
319 refcount_set(&hinfo->use, 1);
320 hinfo->count = 0;
321 hinfo->family = family;
322 hinfo->rnd_initialized = false;
323 hinfo->name = kstrdup(name, GFP_KERNEL);
324 if (!hinfo->name) {
325 vfree(hinfo);
326 return -ENOMEM;
327 }
328 spin_lock_init(&hinfo->lock);
329
330 switch (revision) {
331 case 1:
332 ops = &dl_seq_ops_v1;
333 break;
334 case 2:
335 ops = &dl_seq_ops_v2;
336 break;
337 default:
338 ops = &dl_seq_ops;
339 }
340
341 hinfo->pde = proc_create_seq_data(name, 0,
342 (family == NFPROTO_IPV4) ?
343 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
344 ops, hinfo);
345 if (hinfo->pde == NULL) {
346 kfree(hinfo->name);
347 vfree(hinfo);
348 return -ENOMEM;
349 }
350 hinfo->net = net;
351
352 INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc);
353 queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work,
354 msecs_to_jiffies(hinfo->cfg.gc_interval));
355
356 hlist_add_head(&hinfo->node, &hashlimit_net->htables);
357
358 return 0;
359}
360
361static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, bool select_all)
362{
363 unsigned int i;
364
365 for (i = 0; i < ht->cfg.size; i++) {
366 struct dsthash_ent *dh;
367 struct hlist_node *n;
368
369 spin_lock_bh(&ht->lock);
370 hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) {
371 if (time_after_eq(jiffies, dh->expires) || select_all)
372 dsthash_free(ht, dh);
373 }
374 spin_unlock_bh(&ht->lock);
375 cond_resched();
376 }
377}
378
379static void htable_gc(struct work_struct *work)
380{
381 struct xt_hashlimit_htable *ht;
382
383 ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
384
385 htable_selective_cleanup(ht, false);
386
387 queue_delayed_work(system_power_efficient_wq,
388 &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval));
389}
390
391static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
392{
393 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
394 struct proc_dir_entry *parent;
395
396 if (hinfo->family == NFPROTO_IPV4)
397 parent = hashlimit_net->ipt_hashlimit;
398 else
399 parent = hashlimit_net->ip6t_hashlimit;
400
401 if (parent != NULL)
402 remove_proc_entry(hinfo->name, parent);
403}
404
405static struct xt_hashlimit_htable *htable_find_get(struct net *net,
406 const char *name,
407 u_int8_t family)
408{
409 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
410 struct xt_hashlimit_htable *hinfo;
411
412 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
413 if (!strcmp(name, hinfo->name) &&
414 hinfo->family == family) {
415 refcount_inc(&hinfo->use);
416 return hinfo;
417 }
418 }
419 return NULL;
420}
421
422static void htable_put(struct xt_hashlimit_htable *hinfo)
423{
424 if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) {
425 hlist_del(&hinfo->node);
426 htable_remove_proc_entry(hinfo);
427 mutex_unlock(&hashlimit_mutex);
428
429 cancel_delayed_work_sync(&hinfo->gc_work);
430 htable_selective_cleanup(hinfo, true);
431 kfree(hinfo->name);
432 vfree(hinfo);
433 }
434}
435
436/* The algorithm used is the Simple Token Bucket Filter (TBF)
437 * see net/sched/sch_tbf.c in the linux source tree
438 */
439
440/* Rusty: This is my (non-mathematically-inclined) understanding of
441 this algorithm. The `average rate' in jiffies becomes your initial
442 amount of credit `credit' and the most credit you can ever have
443 `credit_cap'. The `peak rate' becomes the cost of passing the
444 test, `cost'.
445
446 `prev' tracks the last packet hit: you gain one credit per jiffy.
447 If you get credit balance more than this, the extra credit is
448 discarded. Every time the match passes, you lose `cost' credits;
449 if you don't have that many, the test fails.
450
451 See Alexey's formal explanation in net/sched/sch_tbf.c.
452
453 To get the maximum range, we multiply by this factor (ie. you get N
454 credits per jiffy). We want to allow a rate as low as 1 per day
455 (slowest userspace tool allows), which means
456 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
457*/
458#define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24))
459#define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24))
460
461/* Repeated shift and or gives us all 1s, final shift and add 1 gives
462 * us the power of 2 below the theoretical max, so GCC simply does a
463 * shift. */
464#define _POW2_BELOW2(x) ((x)|((x)>>1))
465#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
466#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
467#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
468#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
469#define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32))
470#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
471#define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1)
472
473#define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ)
474#define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1)
475
476/* in byte mode, the lowest possible rate is one packet/second.
477 * credit_cap is used as a counter that tells us how many times we can
478 * refill the "credits available" counter when it becomes empty.
479 */
480#define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
481#define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
482
483static u32 xt_hashlimit_len_to_chunks(u32 len)
484{
485 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
486}
487
488/* Precision saver. */
489static u64 user2credits(u64 user, int revision)
490{
491 u64 scale = (revision == 1) ?
492 XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
493 u64 cpj = (revision == 1) ?
494 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
495
496 /* Avoid overflow: divide the constant operands first */
497 if (scale >= HZ * cpj)
498 return div64_u64(user, div64_u64(scale, HZ * cpj));
499
500 return user * div64_u64(HZ * cpj, scale);
501}
502
503static u32 user2credits_byte(u32 user)
504{
505 u64 us = user;
506 us *= HZ * CREDITS_PER_JIFFY_BYTES;
507 return (u32) (us >> 32);
508}
509
510static u64 user2rate(u64 user)
511{
512 if (user != 0) {
513 return div64_u64(XT_HASHLIMIT_SCALE_v2, user);
514 } else {
515 pr_info_ratelimited("invalid rate from userspace: %llu\n",
516 user);
517 return 0;
518 }
519}
520
521static u64 user2rate_bytes(u32 user)
522{
523 u64 r;
524
525 r = user ? U32_MAX / user : U32_MAX;
526 return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT;
527}
528
529static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now,
530 u32 mode, int revision)
531{
532 unsigned long delta = now - dh->rateinfo.prev;
533 u64 cap, cpj;
534
535 if (delta == 0)
536 return;
537
538 if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) {
539 u64 interval = dh->rateinfo.interval * HZ;
540
541 if (delta < interval)
542 return;
543
544 dh->rateinfo.prev = now;
545 dh->rateinfo.prev_window =
546 ((dh->rateinfo.current_rate * interval) >
547 (delta * dh->rateinfo.rate));
548 dh->rateinfo.current_rate = 0;
549
550 return;
551 }
552
553 dh->rateinfo.prev = now;
554
555 if (mode & XT_HASHLIMIT_BYTES) {
556 u64 tmp = dh->rateinfo.credit;
557 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
558 cap = CREDITS_PER_JIFFY_BYTES * HZ;
559 if (tmp >= dh->rateinfo.credit) {/* overflow */
560 dh->rateinfo.credit = cap;
561 return;
562 }
563 } else {
564 cpj = (revision == 1) ?
565 CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
566 dh->rateinfo.credit += delta * cpj;
567 cap = dh->rateinfo.credit_cap;
568 }
569 if (dh->rateinfo.credit > cap)
570 dh->rateinfo.credit = cap;
571}
572
573static void rateinfo_init(struct dsthash_ent *dh,
574 struct xt_hashlimit_htable *hinfo, int revision)
575{
576 dh->rateinfo.prev = jiffies;
577 if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) {
578 dh->rateinfo.prev_window = 0;
579 dh->rateinfo.current_rate = 0;
580 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
581 dh->rateinfo.rate =
582 user2rate_bytes((u32)hinfo->cfg.avg);
583 if (hinfo->cfg.burst)
584 dh->rateinfo.burst =
585 hinfo->cfg.burst * dh->rateinfo.rate;
586 else
587 dh->rateinfo.burst = dh->rateinfo.rate;
588 } else {
589 dh->rateinfo.rate = user2rate(hinfo->cfg.avg);
590 dh->rateinfo.burst =
591 hinfo->cfg.burst + dh->rateinfo.rate;
592 }
593 dh->rateinfo.interval = hinfo->cfg.interval;
594 } else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
595 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
596 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg);
597 dh->rateinfo.credit_cap = hinfo->cfg.burst;
598 } else {
599 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
600 hinfo->cfg.burst, revision);
601 dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision);
602 dh->rateinfo.credit_cap = dh->rateinfo.credit;
603 }
604}
605
606static inline __be32 maskl(__be32 a, unsigned int l)
607{
608 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
609}
610
611#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
612static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
613{
614 switch (p) {
615 case 0 ... 31:
616 i[0] = maskl(i[0], p);
617 i[1] = i[2] = i[3] = 0;
618 break;
619 case 32 ... 63:
620 i[1] = maskl(i[1], p - 32);
621 i[2] = i[3] = 0;
622 break;
623 case 64 ... 95:
624 i[2] = maskl(i[2], p - 64);
625 i[3] = 0;
626 break;
627 case 96 ... 127:
628 i[3] = maskl(i[3], p - 96);
629 break;
630 case 128:
631 break;
632 }
633}
634#endif
635
636static int
637hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
638 struct dsthash_dst *dst,
639 const struct sk_buff *skb, unsigned int protoff)
640{
641 __be16 _ports[2], *ports;
642 u8 nexthdr;
643 int poff;
644
645 memset(dst, 0, sizeof(*dst));
646
647 switch (hinfo->family) {
648 case NFPROTO_IPV4:
649 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
650 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
651 hinfo->cfg.dstmask);
652 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
653 dst->ip.src = maskl(ip_hdr(skb)->saddr,
654 hinfo->cfg.srcmask);
655
656 if (!(hinfo->cfg.mode &
657 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
658 return 0;
659 nexthdr = ip_hdr(skb)->protocol;
660 break;
661#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
662 case NFPROTO_IPV6:
663 {
664 __be16 frag_off;
665
666 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
667 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
668 sizeof(dst->ip6.dst));
669 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
670 }
671 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
672 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
673 sizeof(dst->ip6.src));
674 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
675 }
676
677 if (!(hinfo->cfg.mode &
678 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
679 return 0;
680 nexthdr = ipv6_hdr(skb)->nexthdr;
681 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off);
682 if ((int)protoff < 0)
683 return -1;
684 break;
685 }
686#endif
687 default:
688 BUG();
689 return 0;
690 }
691
692 poff = proto_ports_offset(nexthdr);
693 if (poff >= 0) {
694 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
695 &_ports);
696 } else {
697 _ports[0] = _ports[1] = 0;
698 ports = _ports;
699 }
700 if (!ports)
701 return -1;
702 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
703 dst->src_port = ports[0];
704 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
705 dst->dst_port = ports[1];
706 return 0;
707}
708
709static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
710{
711 u64 tmp = xt_hashlimit_len_to_chunks(len);
712 tmp = tmp * dh->rateinfo.cost;
713
714 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
715 tmp = CREDITS_PER_JIFFY_BYTES * HZ;
716
717 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
718 dh->rateinfo.credit_cap--;
719 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
720 }
721 return (u32) tmp;
722}
723
724static bool
725hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
726 struct xt_hashlimit_htable *hinfo,
727 const struct hashlimit_cfg3 *cfg, int revision)
728{
729 unsigned long now = jiffies;
730 struct dsthash_ent *dh;
731 struct dsthash_dst dst;
732 bool race = false;
733 u64 cost;
734
735 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
736 goto hotdrop;
737
738 local_bh_disable();
739 dh = dsthash_find(hinfo, &dst);
740 if (dh == NULL) {
741 dh = dsthash_alloc_init(hinfo, &dst, &race);
742 if (dh == NULL) {
743 local_bh_enable();
744 goto hotdrop;
745 } else if (race) {
746 /* Already got an entry, update expiration timeout */
747 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
748 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
749 } else {
750 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
751 rateinfo_init(dh, hinfo, revision);
752 }
753 } else {
754 /* update expiration timeout */
755 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
756 rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
757 }
758
759 if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
760 cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1;
761 dh->rateinfo.current_rate += cost;
762
763 if (!dh->rateinfo.prev_window &&
764 (dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
765 spin_unlock(&dh->lock);
766 local_bh_enable();
767 return !(cfg->mode & XT_HASHLIMIT_INVERT);
768 } else {
769 goto overlimit;
770 }
771 }
772
773 if (cfg->mode & XT_HASHLIMIT_BYTES)
774 cost = hashlimit_byte_cost(skb->len, dh);
775 else
776 cost = dh->rateinfo.cost;
777
778 if (dh->rateinfo.credit >= cost) {
779 /* below the limit */
780 dh->rateinfo.credit -= cost;
781 spin_unlock(&dh->lock);
782 local_bh_enable();
783 return !(cfg->mode & XT_HASHLIMIT_INVERT);
784 }
785
786overlimit:
787 spin_unlock(&dh->lock);
788 local_bh_enable();
789 /* default match is underlimit - so over the limit, we need to invert */
790 return cfg->mode & XT_HASHLIMIT_INVERT;
791
792 hotdrop:
793 par->hotdrop = true;
794 return false;
795}
796
797static bool
798hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
799{
800 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
801 struct xt_hashlimit_htable *hinfo = info->hinfo;
802 struct hashlimit_cfg3 cfg = {};
803 int ret;
804
805 ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
806 if (ret)
807 return ret;
808
809 return hashlimit_mt_common(skb, par, hinfo, &cfg, 1);
810}
811
812static bool
813hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
814{
815 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
816 struct xt_hashlimit_htable *hinfo = info->hinfo;
817 struct hashlimit_cfg3 cfg = {};
818 int ret;
819
820 ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
821 if (ret)
822 return ret;
823
824 return hashlimit_mt_common(skb, par, hinfo, &cfg, 2);
825}
826
827static bool
828hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
829{
830 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
831 struct xt_hashlimit_htable *hinfo = info->hinfo;
832
833 return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3);
834}
835
836#define HASHLIMIT_MAX_SIZE 1048576
837
838static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
839 struct xt_hashlimit_htable **hinfo,
840 struct hashlimit_cfg3 *cfg,
841 const char *name, int revision)
842{
843 struct net *net = par->net;
844 int ret;
845
846 if (cfg->gc_interval == 0 || cfg->expire == 0)
847 return -EINVAL;
848 if (cfg->size > HASHLIMIT_MAX_SIZE) {
849 cfg->size = HASHLIMIT_MAX_SIZE;
850 pr_info_ratelimited("size too large, truncated to %u\n", cfg->size);
851 }
852 if (cfg->max > HASHLIMIT_MAX_SIZE) {
853 cfg->max = HASHLIMIT_MAX_SIZE;
854 pr_info_ratelimited("max too large, truncated to %u\n", cfg->max);
855 }
856 if (par->family == NFPROTO_IPV4) {
857 if (cfg->srcmask > 32 || cfg->dstmask > 32)
858 return -EINVAL;
859 } else {
860 if (cfg->srcmask > 128 || cfg->dstmask > 128)
861 return -EINVAL;
862 }
863
864 if (cfg->mode & ~XT_HASHLIMIT_ALL) {
865 pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n",
866 cfg->mode);
867 return -EINVAL;
868 }
869
870 /* Check for overflow. */
871 if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
872 if (cfg->avg == 0 || cfg->avg > U32_MAX) {
873 pr_info_ratelimited("invalid rate\n");
874 return -ERANGE;
875 }
876
877 if (cfg->interval == 0) {
878 pr_info_ratelimited("invalid interval\n");
879 return -EINVAL;
880 }
881 } else if (cfg->mode & XT_HASHLIMIT_BYTES) {
882 if (user2credits_byte(cfg->avg) == 0) {
883 pr_info_ratelimited("overflow, rate too high: %llu\n",
884 cfg->avg);
885 return -EINVAL;
886 }
887 } else if (cfg->burst == 0 ||
888 user2credits(cfg->avg * cfg->burst, revision) <
889 user2credits(cfg->avg, revision)) {
890 pr_info_ratelimited("overflow, try lower: %llu/%llu\n",
891 cfg->avg, cfg->burst);
892 return -ERANGE;
893 }
894
895 mutex_lock(&hashlimit_mutex);
896 *hinfo = htable_find_get(net, name, par->family);
897 if (*hinfo == NULL) {
898 ret = htable_create(net, cfg, name, par->family,
899 hinfo, revision);
900 if (ret < 0) {
901 mutex_unlock(&hashlimit_mutex);
902 return ret;
903 }
904 }
905 mutex_unlock(&hashlimit_mutex);
906
907 return 0;
908}
909
910static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par)
911{
912 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
913 struct hashlimit_cfg3 cfg = {};
914 int ret;
915
916 ret = xt_check_proc_name(info->name, sizeof(info->name));
917 if (ret)
918 return ret;
919
920 ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
921 if (ret)
922 return ret;
923
924 return hashlimit_mt_check_common(par, &info->hinfo,
925 &cfg, info->name, 1);
926}
927
928static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par)
929{
930 struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
931 struct hashlimit_cfg3 cfg = {};
932 int ret;
933
934 ret = xt_check_proc_name(info->name, sizeof(info->name));
935 if (ret)
936 return ret;
937
938 ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
939 if (ret)
940 return ret;
941
942 return hashlimit_mt_check_common(par, &info->hinfo,
943 &cfg, info->name, 2);
944}
945
946static int hashlimit_mt_check(const struct xt_mtchk_param *par)
947{
948 struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
949 int ret;
950
951 ret = xt_check_proc_name(info->name, sizeof(info->name));
952 if (ret)
953 return ret;
954
955 return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg,
956 info->name, 3);
957}
958
959static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par)
960{
961 const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
962
963 htable_put(info->hinfo);
964}
965
966static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par)
967{
968 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
969
970 htable_put(info->hinfo);
971}
972
973static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
974{
975 const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
976
977 htable_put(info->hinfo);
978}
979
980static struct xt_match hashlimit_mt_reg[] __read_mostly = {
981 {
982 .name = "hashlimit",
983 .revision = 1,
984 .family = NFPROTO_IPV4,
985 .match = hashlimit_mt_v1,
986 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
987 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
988 .checkentry = hashlimit_mt_check_v1,
989 .destroy = hashlimit_mt_destroy_v1,
990 .me = THIS_MODULE,
991 },
992 {
993 .name = "hashlimit",
994 .revision = 2,
995 .family = NFPROTO_IPV4,
996 .match = hashlimit_mt_v2,
997 .matchsize = sizeof(struct xt_hashlimit_mtinfo2),
998 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
999 .checkentry = hashlimit_mt_check_v2,
1000 .destroy = hashlimit_mt_destroy_v2,
1001 .me = THIS_MODULE,
1002 },
1003 {
1004 .name = "hashlimit",
1005 .revision = 3,
1006 .family = NFPROTO_IPV4,
1007 .match = hashlimit_mt,
1008 .matchsize = sizeof(struct xt_hashlimit_mtinfo3),
1009 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1010 .checkentry = hashlimit_mt_check,
1011 .destroy = hashlimit_mt_destroy,
1012 .me = THIS_MODULE,
1013 },
1014#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1015 {
1016 .name = "hashlimit",
1017 .revision = 1,
1018 .family = NFPROTO_IPV6,
1019 .match = hashlimit_mt_v1,
1020 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
1021 .usersize = offsetof(struct xt_hashlimit_mtinfo1, hinfo),
1022 .checkentry = hashlimit_mt_check_v1,
1023 .destroy = hashlimit_mt_destroy_v1,
1024 .me = THIS_MODULE,
1025 },
1026 {
1027 .name = "hashlimit",
1028 .revision = 2,
1029 .family = NFPROTO_IPV6,
1030 .match = hashlimit_mt_v2,
1031 .matchsize = sizeof(struct xt_hashlimit_mtinfo2),
1032 .usersize = offsetof(struct xt_hashlimit_mtinfo2, hinfo),
1033 .checkentry = hashlimit_mt_check_v2,
1034 .destroy = hashlimit_mt_destroy_v2,
1035 .me = THIS_MODULE,
1036 },
1037 {
1038 .name = "hashlimit",
1039 .revision = 3,
1040 .family = NFPROTO_IPV6,
1041 .match = hashlimit_mt,
1042 .matchsize = sizeof(struct xt_hashlimit_mtinfo3),
1043 .usersize = offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1044 .checkentry = hashlimit_mt_check,
1045 .destroy = hashlimit_mt_destroy,
1046 .me = THIS_MODULE,
1047 },
1048#endif
1049};
1050
1051/* PROC stuff */
1052static void *dl_seq_start(struct seq_file *s, loff_t *pos)
1053 __acquires(htable->lock)
1054{
1055 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1056 unsigned int *bucket;
1057
1058 spin_lock_bh(&htable->lock);
1059 if (*pos >= htable->cfg.size)
1060 return NULL;
1061
1062 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
1063 if (!bucket)
1064 return ERR_PTR(-ENOMEM);
1065
1066 *bucket = *pos;
1067 return bucket;
1068}
1069
1070static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
1071{
1072 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1073 unsigned int *bucket = v;
1074
1075 *pos = ++(*bucket);
1076 if (*pos >= htable->cfg.size) {
1077 kfree(v);
1078 return NULL;
1079 }
1080 return bucket;
1081}
1082
1083static void dl_seq_stop(struct seq_file *s, void *v)
1084 __releases(htable->lock)
1085{
1086 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1087 unsigned int *bucket = v;
1088
1089 if (!IS_ERR(bucket))
1090 kfree(bucket);
1091 spin_unlock_bh(&htable->lock);
1092}
1093
1094static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family,
1095 struct seq_file *s)
1096{
1097 switch (family) {
1098 case NFPROTO_IPV4:
1099 seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n",
1100 (long)(ent->expires - jiffies)/HZ,
1101 &ent->dst.ip.src,
1102 ntohs(ent->dst.src_port),
1103 &ent->dst.ip.dst,
1104 ntohs(ent->dst.dst_port),
1105 ent->rateinfo.credit, ent->rateinfo.credit_cap,
1106 ent->rateinfo.cost);
1107 break;
1108#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1109 case NFPROTO_IPV6:
1110 seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n",
1111 (long)(ent->expires - jiffies)/HZ,
1112 &ent->dst.ip6.src,
1113 ntohs(ent->dst.src_port),
1114 &ent->dst.ip6.dst,
1115 ntohs(ent->dst.dst_port),
1116 ent->rateinfo.credit, ent->rateinfo.credit_cap,
1117 ent->rateinfo.cost);
1118 break;
1119#endif
1120 default:
1121 BUG();
1122 }
1123}
1124
1125static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family,
1126 struct seq_file *s)
1127{
1128 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1129
1130 spin_lock(&ent->lock);
1131 /* recalculate to show accurate numbers */
1132 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2);
1133
1134 dl_seq_print(ent, family, s);
1135
1136 spin_unlock(&ent->lock);
1137 return seq_has_overflowed(s);
1138}
1139
1140static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family,
1141 struct seq_file *s)
1142{
1143 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1144
1145 spin_lock(&ent->lock);
1146 /* recalculate to show accurate numbers */
1147 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1);
1148
1149 dl_seq_print(ent, family, s);
1150
1151 spin_unlock(&ent->lock);
1152 return seq_has_overflowed(s);
1153}
1154
1155static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
1156 struct seq_file *s)
1157{
1158 struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1159
1160 spin_lock(&ent->lock);
1161 /* recalculate to show accurate numbers */
1162 rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3);
1163
1164 dl_seq_print(ent, family, s);
1165
1166 spin_unlock(&ent->lock);
1167 return seq_has_overflowed(s);
1168}
1169
1170static int dl_seq_show_v2(struct seq_file *s, void *v)
1171{
1172 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1173 unsigned int *bucket = (unsigned int *)v;
1174 struct dsthash_ent *ent;
1175
1176 if (!hlist_empty(&htable->hash[*bucket])) {
1177 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1178 if (dl_seq_real_show_v2(ent, htable->family, s))
1179 return -1;
1180 }
1181 return 0;
1182}
1183
1184static int dl_seq_show_v1(struct seq_file *s, void *v)
1185{
1186 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1187 unsigned int *bucket = v;
1188 struct dsthash_ent *ent;
1189
1190 if (!hlist_empty(&htable->hash[*bucket])) {
1191 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1192 if (dl_seq_real_show_v1(ent, htable->family, s))
1193 return -1;
1194 }
1195 return 0;
1196}
1197
1198static int dl_seq_show(struct seq_file *s, void *v)
1199{
1200 struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1201 unsigned int *bucket = v;
1202 struct dsthash_ent *ent;
1203
1204 if (!hlist_empty(&htable->hash[*bucket])) {
1205 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1206 if (dl_seq_real_show(ent, htable->family, s))
1207 return -1;
1208 }
1209 return 0;
1210}
1211
1212static const struct seq_operations dl_seq_ops_v1 = {
1213 .start = dl_seq_start,
1214 .next = dl_seq_next,
1215 .stop = dl_seq_stop,
1216 .show = dl_seq_show_v1
1217};
1218
1219static const struct seq_operations dl_seq_ops_v2 = {
1220 .start = dl_seq_start,
1221 .next = dl_seq_next,
1222 .stop = dl_seq_stop,
1223 .show = dl_seq_show_v2
1224};
1225
1226static const struct seq_operations dl_seq_ops = {
1227 .start = dl_seq_start,
1228 .next = dl_seq_next,
1229 .stop = dl_seq_stop,
1230 .show = dl_seq_show
1231};
1232
1233static int __net_init hashlimit_proc_net_init(struct net *net)
1234{
1235 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1236
1237 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
1238 if (!hashlimit_net->ipt_hashlimit)
1239 return -ENOMEM;
1240#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1241 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
1242 if (!hashlimit_net->ip6t_hashlimit) {
1243 remove_proc_entry("ipt_hashlimit", net->proc_net);
1244 return -ENOMEM;
1245 }
1246#endif
1247 return 0;
1248}
1249
1250static void __net_exit hashlimit_proc_net_exit(struct net *net)
1251{
1252 struct xt_hashlimit_htable *hinfo;
1253 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1254
1255 /* hashlimit_net_exit() is called before hashlimit_mt_destroy().
1256 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc
1257 * entries is empty before trying to remove it.
1258 */
1259 mutex_lock(&hashlimit_mutex);
1260 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node)
1261 htable_remove_proc_entry(hinfo);
1262 hashlimit_net->ipt_hashlimit = NULL;
1263 hashlimit_net->ip6t_hashlimit = NULL;
1264 mutex_unlock(&hashlimit_mutex);
1265
1266 remove_proc_entry("ipt_hashlimit", net->proc_net);
1267#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1268 remove_proc_entry("ip6t_hashlimit", net->proc_net);
1269#endif
1270}
1271
1272static int __net_init hashlimit_net_init(struct net *net)
1273{
1274 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1275
1276 INIT_HLIST_HEAD(&hashlimit_net->htables);
1277 return hashlimit_proc_net_init(net);
1278}
1279
1280static void __net_exit hashlimit_net_exit(struct net *net)
1281{
1282 hashlimit_proc_net_exit(net);
1283}
1284
1285static struct pernet_operations hashlimit_net_ops = {
1286 .init = hashlimit_net_init,
1287 .exit = hashlimit_net_exit,
1288 .id = &hashlimit_net_id,
1289 .size = sizeof(struct hashlimit_net),
1290};
1291
1292static int __init hashlimit_mt_init(void)
1293{
1294 int err;
1295
1296 err = register_pernet_subsys(&hashlimit_net_ops);
1297 if (err < 0)
1298 return err;
1299 err = xt_register_matches(hashlimit_mt_reg,
1300 ARRAY_SIZE(hashlimit_mt_reg));
1301 if (err < 0)
1302 goto err1;
1303
1304 err = -ENOMEM;
1305 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
1306 sizeof(struct dsthash_ent), 0, 0,
1307 NULL);
1308 if (!hashlimit_cachep) {
1309 pr_warn("unable to create slab cache\n");
1310 goto err2;
1311 }
1312 return 0;
1313
1314err2:
1315 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1316err1:
1317 unregister_pernet_subsys(&hashlimit_net_ops);
1318 return err;
1319
1320}
1321
1322static void __exit hashlimit_mt_exit(void)
1323{
1324 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1325 unregister_pernet_subsys(&hashlimit_net_ops);
1326
1327 rcu_barrier();
1328 kmem_cache_destroy(hashlimit_cachep);
1329}
1330
1331module_init(hashlimit_mt_init);
1332module_exit(hashlimit_mt_exit);
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 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
7 *
8 * Development of this code was funded by Astaro AG, http://www.astaro.com/
9 */
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11#include <linux/module.h>
12#include <linux/spinlock.h>
13#include <linux/random.h>
14#include <linux/jhash.h>
15#include <linux/slab.h>
16#include <linux/vmalloc.h>
17#include <linux/proc_fs.h>
18#include <linux/seq_file.h>
19#include <linux/list.h>
20#include <linux/skbuff.h>
21#include <linux/mm.h>
22#include <linux/in.h>
23#include <linux/ip.h>
24#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
25#include <linux/ipv6.h>
26#include <net/ipv6.h>
27#endif
28
29#include <net/net_namespace.h>
30#include <net/netns/generic.h>
31
32#include <linux/netfilter/x_tables.h>
33#include <linux/netfilter_ipv4/ip_tables.h>
34#include <linux/netfilter_ipv6/ip6_tables.h>
35#include <linux/netfilter/xt_hashlimit.h>
36#include <linux/mutex.h>
37
38MODULE_LICENSE("GPL");
39MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
40MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
41MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
42MODULE_ALIAS("ipt_hashlimit");
43MODULE_ALIAS("ip6t_hashlimit");
44
45struct hashlimit_net {
46 struct hlist_head htables;
47 struct proc_dir_entry *ipt_hashlimit;
48 struct proc_dir_entry *ip6t_hashlimit;
49};
50
51static int hashlimit_net_id;
52static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
53{
54 return net_generic(net, hashlimit_net_id);
55}
56
57/* need to declare this at the top */
58static const struct file_operations dl_file_ops;
59
60/* hash table crap */
61struct dsthash_dst {
62 union {
63 struct {
64 __be32 src;
65 __be32 dst;
66 } ip;
67#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
68 struct {
69 __be32 src[4];
70 __be32 dst[4];
71 } ip6;
72#endif
73 };
74 __be16 src_port;
75 __be16 dst_port;
76};
77
78struct dsthash_ent {
79 /* static / read-only parts in the beginning */
80 struct hlist_node node;
81 struct dsthash_dst dst;
82
83 /* modified structure members in the end */
84 spinlock_t lock;
85 unsigned long expires; /* precalculated expiry time */
86 struct {
87 unsigned long prev; /* last modification */
88 u_int32_t credit;
89 u_int32_t credit_cap, cost;
90 } rateinfo;
91 struct rcu_head rcu;
92};
93
94struct xt_hashlimit_htable {
95 struct hlist_node node; /* global list of all htables */
96 int use;
97 u_int8_t family;
98 bool rnd_initialized;
99
100 struct hashlimit_cfg1 cfg; /* config */
101
102 /* used internally */
103 spinlock_t lock; /* lock for list_head */
104 u_int32_t rnd; /* random seed for hash */
105 unsigned int count; /* number entries in table */
106 struct timer_list timer; /* timer for gc */
107
108 /* seq_file stuff */
109 struct proc_dir_entry *pde;
110 struct net *net;
111
112 struct hlist_head hash[0]; /* hashtable itself */
113};
114
115static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */
116static struct kmem_cache *hashlimit_cachep __read_mostly;
117
118static inline bool dst_cmp(const struct dsthash_ent *ent,
119 const struct dsthash_dst *b)
120{
121 return !memcmp(&ent->dst, b, sizeof(ent->dst));
122}
123
124static u_int32_t
125hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
126{
127 u_int32_t hash = jhash2((const u32 *)dst,
128 sizeof(*dst)/sizeof(u32),
129 ht->rnd);
130 /*
131 * Instead of returning hash % ht->cfg.size (implying a divide)
132 * we return the high 32 bits of the (hash * ht->cfg.size) that will
133 * give results between [0 and cfg.size-1] and same hash distribution,
134 * but using a multiply, less expensive than a divide
135 */
136 return ((u64)hash * ht->cfg.size) >> 32;
137}
138
139static struct dsthash_ent *
140dsthash_find(const struct xt_hashlimit_htable *ht,
141 const struct dsthash_dst *dst)
142{
143 struct dsthash_ent *ent;
144 struct hlist_node *pos;
145 u_int32_t hash = hash_dst(ht, dst);
146
147 if (!hlist_empty(&ht->hash[hash])) {
148 hlist_for_each_entry_rcu(ent, pos, &ht->hash[hash], node)
149 if (dst_cmp(ent, dst)) {
150 spin_lock(&ent->lock);
151 return ent;
152 }
153 }
154 return NULL;
155}
156
157/* allocate dsthash_ent, initialize dst, put in htable and lock it */
158static struct dsthash_ent *
159dsthash_alloc_init(struct xt_hashlimit_htable *ht,
160 const struct dsthash_dst *dst)
161{
162 struct dsthash_ent *ent;
163
164 spin_lock(&ht->lock);
165 /* initialize hash with random val at the time we allocate
166 * the first hashtable entry */
167 if (unlikely(!ht->rnd_initialized)) {
168 get_random_bytes(&ht->rnd, sizeof(ht->rnd));
169 ht->rnd_initialized = true;
170 }
171
172 if (ht->cfg.max && ht->count >= ht->cfg.max) {
173 /* FIXME: do something. question is what.. */
174 if (net_ratelimit())
175 pr_err("max count of %u reached\n", ht->cfg.max);
176 ent = NULL;
177 } else
178 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
179 if (!ent) {
180 if (net_ratelimit())
181 pr_err("cannot allocate dsthash_ent\n");
182 } else {
183 memcpy(&ent->dst, dst, sizeof(ent->dst));
184 spin_lock_init(&ent->lock);
185
186 spin_lock(&ent->lock);
187 hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]);
188 ht->count++;
189 }
190 spin_unlock(&ht->lock);
191 return ent;
192}
193
194static void dsthash_free_rcu(struct rcu_head *head)
195{
196 struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
197
198 kmem_cache_free(hashlimit_cachep, ent);
199}
200
201static inline void
202dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
203{
204 hlist_del_rcu(&ent->node);
205 call_rcu_bh(&ent->rcu, dsthash_free_rcu);
206 ht->count--;
207}
208static void htable_gc(unsigned long htlong);
209
210static int htable_create(struct net *net, struct xt_hashlimit_mtinfo1 *minfo,
211 u_int8_t family)
212{
213 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
214 struct xt_hashlimit_htable *hinfo;
215 unsigned int size;
216 unsigned int i;
217
218 if (minfo->cfg.size) {
219 size = minfo->cfg.size;
220 } else {
221 size = (totalram_pages << PAGE_SHIFT) / 16384 /
222 sizeof(struct list_head);
223 if (totalram_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
224 size = 8192;
225 if (size < 16)
226 size = 16;
227 }
228 /* FIXME: don't use vmalloc() here or anywhere else -HW */
229 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
230 sizeof(struct list_head) * size);
231 if (hinfo == NULL)
232 return -ENOMEM;
233 minfo->hinfo = hinfo;
234
235 /* copy match config into hashtable config */
236 memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
237 hinfo->cfg.size = size;
238 if (hinfo->cfg.max == 0)
239 hinfo->cfg.max = 8 * hinfo->cfg.size;
240 else if (hinfo->cfg.max < hinfo->cfg.size)
241 hinfo->cfg.max = hinfo->cfg.size;
242
243 for (i = 0; i < hinfo->cfg.size; i++)
244 INIT_HLIST_HEAD(&hinfo->hash[i]);
245
246 hinfo->use = 1;
247 hinfo->count = 0;
248 hinfo->family = family;
249 hinfo->rnd_initialized = false;
250 spin_lock_init(&hinfo->lock);
251
252 hinfo->pde = proc_create_data(minfo->name, 0,
253 (family == NFPROTO_IPV4) ?
254 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
255 &dl_file_ops, hinfo);
256 if (hinfo->pde == NULL) {
257 vfree(hinfo);
258 return -ENOMEM;
259 }
260 hinfo->net = net;
261
262 setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo);
263 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
264 add_timer(&hinfo->timer);
265
266 hlist_add_head(&hinfo->node, &hashlimit_net->htables);
267
268 return 0;
269}
270
271static bool select_all(const struct xt_hashlimit_htable *ht,
272 const struct dsthash_ent *he)
273{
274 return 1;
275}
276
277static bool select_gc(const struct xt_hashlimit_htable *ht,
278 const struct dsthash_ent *he)
279{
280 return time_after_eq(jiffies, he->expires);
281}
282
283static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
284 bool (*select)(const struct xt_hashlimit_htable *ht,
285 const struct dsthash_ent *he))
286{
287 unsigned int i;
288
289 /* lock hash table and iterate over it */
290 spin_lock_bh(&ht->lock);
291 for (i = 0; i < ht->cfg.size; i++) {
292 struct dsthash_ent *dh;
293 struct hlist_node *pos, *n;
294 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
295 if ((*select)(ht, dh))
296 dsthash_free(ht, dh);
297 }
298 }
299 spin_unlock_bh(&ht->lock);
300}
301
302/* hash table garbage collector, run by timer */
303static void htable_gc(unsigned long htlong)
304{
305 struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
306
307 htable_selective_cleanup(ht, select_gc);
308
309 /* re-add the timer accordingly */
310 ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
311 add_timer(&ht->timer);
312}
313
314static void htable_destroy(struct xt_hashlimit_htable *hinfo)
315{
316 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
317 struct proc_dir_entry *parent;
318
319 del_timer_sync(&hinfo->timer);
320
321 if (hinfo->family == NFPROTO_IPV4)
322 parent = hashlimit_net->ipt_hashlimit;
323 else
324 parent = hashlimit_net->ip6t_hashlimit;
325 remove_proc_entry(hinfo->pde->name, parent);
326 htable_selective_cleanup(hinfo, select_all);
327 vfree(hinfo);
328}
329
330static struct xt_hashlimit_htable *htable_find_get(struct net *net,
331 const char *name,
332 u_int8_t family)
333{
334 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
335 struct xt_hashlimit_htable *hinfo;
336 struct hlist_node *pos;
337
338 hlist_for_each_entry(hinfo, pos, &hashlimit_net->htables, node) {
339 if (!strcmp(name, hinfo->pde->name) &&
340 hinfo->family == family) {
341 hinfo->use++;
342 return hinfo;
343 }
344 }
345 return NULL;
346}
347
348static void htable_put(struct xt_hashlimit_htable *hinfo)
349{
350 mutex_lock(&hashlimit_mutex);
351 if (--hinfo->use == 0) {
352 hlist_del(&hinfo->node);
353 htable_destroy(hinfo);
354 }
355 mutex_unlock(&hashlimit_mutex);
356}
357
358/* The algorithm used is the Simple Token Bucket Filter (TBF)
359 * see net/sched/sch_tbf.c in the linux source tree
360 */
361
362/* Rusty: This is my (non-mathematically-inclined) understanding of
363 this algorithm. The `average rate' in jiffies becomes your initial
364 amount of credit `credit' and the most credit you can ever have
365 `credit_cap'. The `peak rate' becomes the cost of passing the
366 test, `cost'.
367
368 `prev' tracks the last packet hit: you gain one credit per jiffy.
369 If you get credit balance more than this, the extra credit is
370 discarded. Every time the match passes, you lose `cost' credits;
371 if you don't have that many, the test fails.
372
373 See Alexey's formal explanation in net/sched/sch_tbf.c.
374
375 To get the maximum range, we multiply by this factor (ie. you get N
376 credits per jiffy). We want to allow a rate as low as 1 per day
377 (slowest userspace tool allows), which means
378 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
379*/
380#define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
381
382/* Repeated shift and or gives us all 1s, final shift and add 1 gives
383 * us the power of 2 below the theoretical max, so GCC simply does a
384 * shift. */
385#define _POW2_BELOW2(x) ((x)|((x)>>1))
386#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
387#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
388#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
389#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
390#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
391
392#define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
393
394/* Precision saver. */
395static inline u_int32_t
396user2credits(u_int32_t user)
397{
398 /* If multiplying would overflow... */
399 if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
400 /* Divide first. */
401 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
402
403 return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
404}
405
406static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
407{
408 dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
409 if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
410 dh->rateinfo.credit = dh->rateinfo.credit_cap;
411 dh->rateinfo.prev = now;
412}
413
414static inline __be32 maskl(__be32 a, unsigned int l)
415{
416 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
417}
418
419#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
420static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
421{
422 switch (p) {
423 case 0 ... 31:
424 i[0] = maskl(i[0], p);
425 i[1] = i[2] = i[3] = 0;
426 break;
427 case 32 ... 63:
428 i[1] = maskl(i[1], p - 32);
429 i[2] = i[3] = 0;
430 break;
431 case 64 ... 95:
432 i[2] = maskl(i[2], p - 64);
433 i[3] = 0;
434 break;
435 case 96 ... 127:
436 i[3] = maskl(i[3], p - 96);
437 break;
438 case 128:
439 break;
440 }
441}
442#endif
443
444static int
445hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
446 struct dsthash_dst *dst,
447 const struct sk_buff *skb, unsigned int protoff)
448{
449 __be16 _ports[2], *ports;
450 u8 nexthdr;
451 int poff;
452
453 memset(dst, 0, sizeof(*dst));
454
455 switch (hinfo->family) {
456 case NFPROTO_IPV4:
457 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
458 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
459 hinfo->cfg.dstmask);
460 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
461 dst->ip.src = maskl(ip_hdr(skb)->saddr,
462 hinfo->cfg.srcmask);
463
464 if (!(hinfo->cfg.mode &
465 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
466 return 0;
467 nexthdr = ip_hdr(skb)->protocol;
468 break;
469#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
470 case NFPROTO_IPV6:
471 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
472 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
473 sizeof(dst->ip6.dst));
474 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
475 }
476 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
477 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
478 sizeof(dst->ip6.src));
479 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
480 }
481
482 if (!(hinfo->cfg.mode &
483 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
484 return 0;
485 nexthdr = ipv6_hdr(skb)->nexthdr;
486 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
487 if ((int)protoff < 0)
488 return -1;
489 break;
490#endif
491 default:
492 BUG();
493 return 0;
494 }
495
496 poff = proto_ports_offset(nexthdr);
497 if (poff >= 0) {
498 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
499 &_ports);
500 } else {
501 _ports[0] = _ports[1] = 0;
502 ports = _ports;
503 }
504 if (!ports)
505 return -1;
506 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
507 dst->src_port = ports[0];
508 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
509 dst->dst_port = ports[1];
510 return 0;
511}
512
513static bool
514hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
515{
516 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
517 struct xt_hashlimit_htable *hinfo = info->hinfo;
518 unsigned long now = jiffies;
519 struct dsthash_ent *dh;
520 struct dsthash_dst dst;
521
522 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
523 goto hotdrop;
524
525 rcu_read_lock_bh();
526 dh = dsthash_find(hinfo, &dst);
527 if (dh == NULL) {
528 dh = dsthash_alloc_init(hinfo, &dst);
529 if (dh == NULL) {
530 rcu_read_unlock_bh();
531 goto hotdrop;
532 }
533 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
534 dh->rateinfo.prev = jiffies;
535 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
536 hinfo->cfg.burst);
537 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
538 hinfo->cfg.burst);
539 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
540 } else {
541 /* update expiration timeout */
542 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
543 rateinfo_recalc(dh, now);
544 }
545
546 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
547 /* below the limit */
548 dh->rateinfo.credit -= dh->rateinfo.cost;
549 spin_unlock(&dh->lock);
550 rcu_read_unlock_bh();
551 return !(info->cfg.mode & XT_HASHLIMIT_INVERT);
552 }
553
554 spin_unlock(&dh->lock);
555 rcu_read_unlock_bh();
556 /* default match is underlimit - so over the limit, we need to invert */
557 return info->cfg.mode & XT_HASHLIMIT_INVERT;
558
559 hotdrop:
560 par->hotdrop = true;
561 return false;
562}
563
564static int hashlimit_mt_check(const struct xt_mtchk_param *par)
565{
566 struct net *net = par->net;
567 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
568 int ret;
569
570 /* Check for overflow. */
571 if (info->cfg.burst == 0 ||
572 user2credits(info->cfg.avg * info->cfg.burst) <
573 user2credits(info->cfg.avg)) {
574 pr_info("overflow, try lower: %u/%u\n",
575 info->cfg.avg, info->cfg.burst);
576 return -ERANGE;
577 }
578 if (info->cfg.gc_interval == 0 || info->cfg.expire == 0)
579 return -EINVAL;
580 if (info->name[sizeof(info->name)-1] != '\0')
581 return -EINVAL;
582 if (par->family == NFPROTO_IPV4) {
583 if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32)
584 return -EINVAL;
585 } else {
586 if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128)
587 return -EINVAL;
588 }
589
590 mutex_lock(&hashlimit_mutex);
591 info->hinfo = htable_find_get(net, info->name, par->family);
592 if (info->hinfo == NULL) {
593 ret = htable_create(net, info, par->family);
594 if (ret < 0) {
595 mutex_unlock(&hashlimit_mutex);
596 return ret;
597 }
598 }
599 mutex_unlock(&hashlimit_mutex);
600 return 0;
601}
602
603static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
604{
605 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
606
607 htable_put(info->hinfo);
608}
609
610static struct xt_match hashlimit_mt_reg[] __read_mostly = {
611 {
612 .name = "hashlimit",
613 .revision = 1,
614 .family = NFPROTO_IPV4,
615 .match = hashlimit_mt,
616 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
617 .checkentry = hashlimit_mt_check,
618 .destroy = hashlimit_mt_destroy,
619 .me = THIS_MODULE,
620 },
621#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
622 {
623 .name = "hashlimit",
624 .revision = 1,
625 .family = NFPROTO_IPV6,
626 .match = hashlimit_mt,
627 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
628 .checkentry = hashlimit_mt_check,
629 .destroy = hashlimit_mt_destroy,
630 .me = THIS_MODULE,
631 },
632#endif
633};
634
635/* PROC stuff */
636static void *dl_seq_start(struct seq_file *s, loff_t *pos)
637 __acquires(htable->lock)
638{
639 struct xt_hashlimit_htable *htable = s->private;
640 unsigned int *bucket;
641
642 spin_lock_bh(&htable->lock);
643 if (*pos >= htable->cfg.size)
644 return NULL;
645
646 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
647 if (!bucket)
648 return ERR_PTR(-ENOMEM);
649
650 *bucket = *pos;
651 return bucket;
652}
653
654static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
655{
656 struct xt_hashlimit_htable *htable = s->private;
657 unsigned int *bucket = (unsigned int *)v;
658
659 *pos = ++(*bucket);
660 if (*pos >= htable->cfg.size) {
661 kfree(v);
662 return NULL;
663 }
664 return bucket;
665}
666
667static void dl_seq_stop(struct seq_file *s, void *v)
668 __releases(htable->lock)
669{
670 struct xt_hashlimit_htable *htable = s->private;
671 unsigned int *bucket = (unsigned int *)v;
672
673 if (!IS_ERR(bucket))
674 kfree(bucket);
675 spin_unlock_bh(&htable->lock);
676}
677
678static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
679 struct seq_file *s)
680{
681 int res;
682
683 spin_lock(&ent->lock);
684 /* recalculate to show accurate numbers */
685 rateinfo_recalc(ent, jiffies);
686
687 switch (family) {
688 case NFPROTO_IPV4:
689 res = seq_printf(s, "%ld %pI4:%u->%pI4:%u %u %u %u\n",
690 (long)(ent->expires - jiffies)/HZ,
691 &ent->dst.ip.src,
692 ntohs(ent->dst.src_port),
693 &ent->dst.ip.dst,
694 ntohs(ent->dst.dst_port),
695 ent->rateinfo.credit, ent->rateinfo.credit_cap,
696 ent->rateinfo.cost);
697 break;
698#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
699 case NFPROTO_IPV6:
700 res = seq_printf(s, "%ld %pI6:%u->%pI6:%u %u %u %u\n",
701 (long)(ent->expires - jiffies)/HZ,
702 &ent->dst.ip6.src,
703 ntohs(ent->dst.src_port),
704 &ent->dst.ip6.dst,
705 ntohs(ent->dst.dst_port),
706 ent->rateinfo.credit, ent->rateinfo.credit_cap,
707 ent->rateinfo.cost);
708 break;
709#endif
710 default:
711 BUG();
712 res = 0;
713 }
714 spin_unlock(&ent->lock);
715 return res;
716}
717
718static int dl_seq_show(struct seq_file *s, void *v)
719{
720 struct xt_hashlimit_htable *htable = s->private;
721 unsigned int *bucket = (unsigned int *)v;
722 struct dsthash_ent *ent;
723 struct hlist_node *pos;
724
725 if (!hlist_empty(&htable->hash[*bucket])) {
726 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
727 if (dl_seq_real_show(ent, htable->family, s))
728 return -1;
729 }
730 return 0;
731}
732
733static const struct seq_operations dl_seq_ops = {
734 .start = dl_seq_start,
735 .next = dl_seq_next,
736 .stop = dl_seq_stop,
737 .show = dl_seq_show
738};
739
740static int dl_proc_open(struct inode *inode, struct file *file)
741{
742 int ret = seq_open(file, &dl_seq_ops);
743
744 if (!ret) {
745 struct seq_file *sf = file->private_data;
746 sf->private = PDE(inode)->data;
747 }
748 return ret;
749}
750
751static const struct file_operations dl_file_ops = {
752 .owner = THIS_MODULE,
753 .open = dl_proc_open,
754 .read = seq_read,
755 .llseek = seq_lseek,
756 .release = seq_release
757};
758
759static int __net_init hashlimit_proc_net_init(struct net *net)
760{
761 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
762
763 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
764 if (!hashlimit_net->ipt_hashlimit)
765 return -ENOMEM;
766#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
767 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
768 if (!hashlimit_net->ip6t_hashlimit) {
769 proc_net_remove(net, "ipt_hashlimit");
770 return -ENOMEM;
771 }
772#endif
773 return 0;
774}
775
776static void __net_exit hashlimit_proc_net_exit(struct net *net)
777{
778 proc_net_remove(net, "ipt_hashlimit");
779#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
780 proc_net_remove(net, "ip6t_hashlimit");
781#endif
782}
783
784static int __net_init hashlimit_net_init(struct net *net)
785{
786 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
787
788 INIT_HLIST_HEAD(&hashlimit_net->htables);
789 return hashlimit_proc_net_init(net);
790}
791
792static void __net_exit hashlimit_net_exit(struct net *net)
793{
794 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
795
796 BUG_ON(!hlist_empty(&hashlimit_net->htables));
797 hashlimit_proc_net_exit(net);
798}
799
800static struct pernet_operations hashlimit_net_ops = {
801 .init = hashlimit_net_init,
802 .exit = hashlimit_net_exit,
803 .id = &hashlimit_net_id,
804 .size = sizeof(struct hashlimit_net),
805};
806
807static int __init hashlimit_mt_init(void)
808{
809 int err;
810
811 err = register_pernet_subsys(&hashlimit_net_ops);
812 if (err < 0)
813 return err;
814 err = xt_register_matches(hashlimit_mt_reg,
815 ARRAY_SIZE(hashlimit_mt_reg));
816 if (err < 0)
817 goto err1;
818
819 err = -ENOMEM;
820 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
821 sizeof(struct dsthash_ent), 0, 0,
822 NULL);
823 if (!hashlimit_cachep) {
824 pr_warning("unable to create slab cache\n");
825 goto err2;
826 }
827 return 0;
828
829err2:
830 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
831err1:
832 unregister_pernet_subsys(&hashlimit_net_ops);
833 return err;
834
835}
836
837static void __exit hashlimit_mt_exit(void)
838{
839 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
840 unregister_pernet_subsys(&hashlimit_net_ops);
841
842 rcu_barrier_bh();
843 kmem_cache_destroy(hashlimit_cachep);
844}
845
846module_init(hashlimit_mt_init);
847module_exit(hashlimit_mt_exit);