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Merge branch 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze
[mirror_ubuntu-bionic-kernel.git] / net / netfilter / xt_hashlimit.c
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 #include <linux/module.h>
11 #include <linux/spinlock.h>
12 #include <linux/random.h>
13 #include <linux/jhash.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <linux/proc_fs.h>
17 #include <linux/seq_file.h>
18 #include <linux/list.h>
19 #include <linux/skbuff.h>
20 #include <linux/mm.h>
21 #include <linux/in.h>
22 #include <linux/ip.h>
23 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
24 #include <linux/ipv6.h>
25 #include <net/ipv6.h>
26 #endif
27
28 #include <net/net_namespace.h>
29 #include <net/netns/generic.h>
30
31 #include <linux/netfilter/x_tables.h>
32 #include <linux/netfilter_ipv4/ip_tables.h>
33 #include <linux/netfilter_ipv6/ip6_tables.h>
34 #include <linux/netfilter/xt_hashlimit.h>
35 #include <linux/mutex.h>
36
37 MODULE_LICENSE("GPL");
38 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
39 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
40 MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
41 MODULE_ALIAS("ipt_hashlimit");
42 MODULE_ALIAS("ip6t_hashlimit");
43
44 struct hashlimit_net {
45 struct hlist_head htables;
46 struct proc_dir_entry *ipt_hashlimit;
47 struct proc_dir_entry *ip6t_hashlimit;
48 };
49
50 static int hashlimit_net_id;
51 static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
52 {
53 return net_generic(net, hashlimit_net_id);
54 }
55
56 /* need to declare this at the top */
57 static const struct file_operations dl_file_ops;
58
59 /* hash table crap */
60 struct dsthash_dst {
61 union {
62 struct {
63 __be32 src;
64 __be32 dst;
65 } ip;
66 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
67 struct {
68 __be32 src[4];
69 __be32 dst[4];
70 } ip6;
71 #endif
72 };
73 __be16 src_port;
74 __be16 dst_port;
75 };
76
77 struct dsthash_ent {
78 /* static / read-only parts in the beginning */
79 struct hlist_node node;
80 struct dsthash_dst dst;
81
82 /* modified structure members in the end */
83 unsigned long expires; /* precalculated expiry time */
84 struct {
85 unsigned long prev; /* last modification */
86 u_int32_t credit;
87 u_int32_t credit_cap, cost;
88 } rateinfo;
89 };
90
91 struct xt_hashlimit_htable {
92 struct hlist_node node; /* global list of all htables */
93 int use;
94 u_int8_t family;
95 bool rnd_initialized;
96
97 struct hashlimit_cfg1 cfg; /* config */
98
99 /* used internally */
100 spinlock_t lock; /* lock for list_head */
101 u_int32_t rnd; /* random seed for hash */
102 unsigned int count; /* number entries in table */
103 struct timer_list timer; /* timer for gc */
104
105 /* seq_file stuff */
106 struct proc_dir_entry *pde;
107 struct net *net;
108
109 struct hlist_head hash[0]; /* hashtable itself */
110 };
111
112 static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */
113 static struct kmem_cache *hashlimit_cachep __read_mostly;
114
115 static inline bool dst_cmp(const struct dsthash_ent *ent,
116 const struct dsthash_dst *b)
117 {
118 return !memcmp(&ent->dst, b, sizeof(ent->dst));
119 }
120
121 static u_int32_t
122 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
123 {
124 u_int32_t hash = jhash2((const u32 *)dst,
125 sizeof(*dst)/sizeof(u32),
126 ht->rnd);
127 /*
128 * Instead of returning hash % ht->cfg.size (implying a divide)
129 * we return the high 32 bits of the (hash * ht->cfg.size) that will
130 * give results between [0 and cfg.size-1] and same hash distribution,
131 * but using a multiply, less expensive than a divide
132 */
133 return ((u64)hash * ht->cfg.size) >> 32;
134 }
135
136 static struct dsthash_ent *
137 dsthash_find(const struct xt_hashlimit_htable *ht,
138 const struct dsthash_dst *dst)
139 {
140 struct dsthash_ent *ent;
141 struct hlist_node *pos;
142 u_int32_t hash = hash_dst(ht, dst);
143
144 if (!hlist_empty(&ht->hash[hash])) {
145 hlist_for_each_entry(ent, pos, &ht->hash[hash], node)
146 if (dst_cmp(ent, dst))
147 return ent;
148 }
149 return NULL;
150 }
151
152 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
153 static struct dsthash_ent *
154 dsthash_alloc_init(struct xt_hashlimit_htable *ht,
155 const struct dsthash_dst *dst)
156 {
157 struct dsthash_ent *ent;
158
159 /* initialize hash with random val at the time we allocate
160 * the first hashtable entry */
161 if (!ht->rnd_initialized) {
162 get_random_bytes(&ht->rnd, sizeof(ht->rnd));
163 ht->rnd_initialized = true;
164 }
165
166 if (ht->cfg.max && ht->count >= ht->cfg.max) {
167 /* FIXME: do something. question is what.. */
168 if (net_ratelimit())
169 printk(KERN_WARNING
170 "xt_hashlimit: max count of %u reached\n",
171 ht->cfg.max);
172 return NULL;
173 }
174
175 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
176 if (!ent) {
177 if (net_ratelimit())
178 printk(KERN_ERR
179 "xt_hashlimit: can't allocate dsthash_ent\n");
180 return NULL;
181 }
182 memcpy(&ent->dst, dst, sizeof(ent->dst));
183
184 hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
185 ht->count++;
186 return ent;
187 }
188
189 static inline void
190 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
191 {
192 hlist_del(&ent->node);
193 kmem_cache_free(hashlimit_cachep, ent);
194 ht->count--;
195 }
196 static void htable_gc(unsigned long htlong);
197
198 static int htable_create_v0(struct net *net, struct xt_hashlimit_info *minfo, u_int8_t family)
199 {
200 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
201 struct xt_hashlimit_htable *hinfo;
202 unsigned int size;
203 unsigned int i;
204
205 if (minfo->cfg.size)
206 size = minfo->cfg.size;
207 else {
208 size = ((totalram_pages << PAGE_SHIFT) / 16384) /
209 sizeof(struct list_head);
210 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
211 size = 8192;
212 if (size < 16)
213 size = 16;
214 }
215 /* FIXME: don't use vmalloc() here or anywhere else -HW */
216 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
217 sizeof(struct list_head) * size);
218 if (!hinfo) {
219 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
220 return -1;
221 }
222 minfo->hinfo = hinfo;
223
224 /* copy match config into hashtable config */
225 hinfo->cfg.mode = minfo->cfg.mode;
226 hinfo->cfg.avg = minfo->cfg.avg;
227 hinfo->cfg.burst = minfo->cfg.burst;
228 hinfo->cfg.max = minfo->cfg.max;
229 hinfo->cfg.gc_interval = minfo->cfg.gc_interval;
230 hinfo->cfg.expire = minfo->cfg.expire;
231
232 if (family == NFPROTO_IPV4)
233 hinfo->cfg.srcmask = hinfo->cfg.dstmask = 32;
234 else
235 hinfo->cfg.srcmask = hinfo->cfg.dstmask = 128;
236
237 hinfo->cfg.size = size;
238 if (!hinfo->cfg.max)
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 hinfo->pde = proc_create_data(minfo->name, 0,
252 (family == NFPROTO_IPV4) ?
253 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
254 &dl_file_ops, hinfo);
255 if (!hinfo->pde) {
256 vfree(hinfo);
257 return -1;
258 }
259 hinfo->net = net;
260
261 setup_timer(&hinfo->timer, htable_gc, (unsigned long )hinfo);
262 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
263 add_timer(&hinfo->timer);
264
265 hlist_add_head(&hinfo->node, &hashlimit_net->htables);
266
267 return 0;
268 }
269
270 static int htable_create(struct net *net, struct xt_hashlimit_mtinfo1 *minfo,
271 u_int8_t family)
272 {
273 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
274 struct xt_hashlimit_htable *hinfo;
275 unsigned int size;
276 unsigned int i;
277
278 if (minfo->cfg.size) {
279 size = minfo->cfg.size;
280 } else {
281 size = (totalram_pages << PAGE_SHIFT) / 16384 /
282 sizeof(struct list_head);
283 if (totalram_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
284 size = 8192;
285 if (size < 16)
286 size = 16;
287 }
288 /* FIXME: don't use vmalloc() here or anywhere else -HW */
289 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
290 sizeof(struct list_head) * size);
291 if (hinfo == NULL) {
292 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
293 return -1;
294 }
295 minfo->hinfo = hinfo;
296
297 /* copy match config into hashtable config */
298 memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
299 hinfo->cfg.size = size;
300 if (hinfo->cfg.max == 0)
301 hinfo->cfg.max = 8 * hinfo->cfg.size;
302 else if (hinfo->cfg.max < hinfo->cfg.size)
303 hinfo->cfg.max = hinfo->cfg.size;
304
305 for (i = 0; i < hinfo->cfg.size; i++)
306 INIT_HLIST_HEAD(&hinfo->hash[i]);
307
308 hinfo->use = 1;
309 hinfo->count = 0;
310 hinfo->family = family;
311 hinfo->rnd_initialized = false;
312 spin_lock_init(&hinfo->lock);
313
314 hinfo->pde = proc_create_data(minfo->name, 0,
315 (family == NFPROTO_IPV4) ?
316 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
317 &dl_file_ops, hinfo);
318 if (hinfo->pde == NULL) {
319 vfree(hinfo);
320 return -1;
321 }
322 hinfo->net = net;
323
324 setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo);
325 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
326 add_timer(&hinfo->timer);
327
328 hlist_add_head(&hinfo->node, &hashlimit_net->htables);
329
330 return 0;
331 }
332
333 static bool select_all(const struct xt_hashlimit_htable *ht,
334 const struct dsthash_ent *he)
335 {
336 return 1;
337 }
338
339 static bool select_gc(const struct xt_hashlimit_htable *ht,
340 const struct dsthash_ent *he)
341 {
342 return time_after_eq(jiffies, he->expires);
343 }
344
345 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
346 bool (*select)(const struct xt_hashlimit_htable *ht,
347 const struct dsthash_ent *he))
348 {
349 unsigned int i;
350
351 /* lock hash table and iterate over it */
352 spin_lock_bh(&ht->lock);
353 for (i = 0; i < ht->cfg.size; i++) {
354 struct dsthash_ent *dh;
355 struct hlist_node *pos, *n;
356 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
357 if ((*select)(ht, dh))
358 dsthash_free(ht, dh);
359 }
360 }
361 spin_unlock_bh(&ht->lock);
362 }
363
364 /* hash table garbage collector, run by timer */
365 static void htable_gc(unsigned long htlong)
366 {
367 struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
368
369 htable_selective_cleanup(ht, select_gc);
370
371 /* re-add the timer accordingly */
372 ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
373 add_timer(&ht->timer);
374 }
375
376 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
377 {
378 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
379 struct proc_dir_entry *parent;
380
381 del_timer_sync(&hinfo->timer);
382
383 if (hinfo->family == NFPROTO_IPV4)
384 parent = hashlimit_net->ipt_hashlimit;
385 else
386 parent = hashlimit_net->ip6t_hashlimit;
387 remove_proc_entry(hinfo->pde->name, parent);
388 htable_selective_cleanup(hinfo, select_all);
389 vfree(hinfo);
390 }
391
392 static struct xt_hashlimit_htable *htable_find_get(struct net *net,
393 const char *name,
394 u_int8_t family)
395 {
396 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
397 struct xt_hashlimit_htable *hinfo;
398 struct hlist_node *pos;
399
400 hlist_for_each_entry(hinfo, pos, &hashlimit_net->htables, node) {
401 if (!strcmp(name, hinfo->pde->name) &&
402 hinfo->family == family) {
403 hinfo->use++;
404 return hinfo;
405 }
406 }
407 return NULL;
408 }
409
410 static void htable_put(struct xt_hashlimit_htable *hinfo)
411 {
412 mutex_lock(&hashlimit_mutex);
413 if (--hinfo->use == 0) {
414 hlist_del(&hinfo->node);
415 htable_destroy(hinfo);
416 }
417 mutex_unlock(&hashlimit_mutex);
418 }
419
420 /* The algorithm used is the Simple Token Bucket Filter (TBF)
421 * see net/sched/sch_tbf.c in the linux source tree
422 */
423
424 /* Rusty: This is my (non-mathematically-inclined) understanding of
425 this algorithm. The `average rate' in jiffies becomes your initial
426 amount of credit `credit' and the most credit you can ever have
427 `credit_cap'. The `peak rate' becomes the cost of passing the
428 test, `cost'.
429
430 `prev' tracks the last packet hit: you gain one credit per jiffy.
431 If you get credit balance more than this, the extra credit is
432 discarded. Every time the match passes, you lose `cost' credits;
433 if you don't have that many, the test fails.
434
435 See Alexey's formal explanation in net/sched/sch_tbf.c.
436
437 To get the maximum range, we multiply by this factor (ie. you get N
438 credits per jiffy). We want to allow a rate as low as 1 per day
439 (slowest userspace tool allows), which means
440 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
441 */
442 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
443
444 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
445 * us the power of 2 below the theoretical max, so GCC simply does a
446 * shift. */
447 #define _POW2_BELOW2(x) ((x)|((x)>>1))
448 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
449 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
450 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
451 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
452 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
453
454 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
455
456 /* Precision saver. */
457 static inline u_int32_t
458 user2credits(u_int32_t user)
459 {
460 /* If multiplying would overflow... */
461 if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
462 /* Divide first. */
463 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
464
465 return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
466 }
467
468 static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
469 {
470 dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
471 if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
472 dh->rateinfo.credit = dh->rateinfo.credit_cap;
473 dh->rateinfo.prev = now;
474 }
475
476 static inline __be32 maskl(__be32 a, unsigned int l)
477 {
478 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
479 }
480
481 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
482 static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
483 {
484 switch (p) {
485 case 0 ... 31:
486 i[0] = maskl(i[0], p);
487 i[1] = i[2] = i[3] = 0;
488 break;
489 case 32 ... 63:
490 i[1] = maskl(i[1], p - 32);
491 i[2] = i[3] = 0;
492 break;
493 case 64 ... 95:
494 i[2] = maskl(i[2], p - 64);
495 i[3] = 0;
496 case 96 ... 127:
497 i[3] = maskl(i[3], p - 96);
498 break;
499 case 128:
500 break;
501 }
502 }
503 #endif
504
505 static int
506 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
507 struct dsthash_dst *dst,
508 const struct sk_buff *skb, unsigned int protoff)
509 {
510 __be16 _ports[2], *ports;
511 u8 nexthdr;
512
513 memset(dst, 0, sizeof(*dst));
514
515 switch (hinfo->family) {
516 case NFPROTO_IPV4:
517 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
518 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
519 hinfo->cfg.dstmask);
520 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
521 dst->ip.src = maskl(ip_hdr(skb)->saddr,
522 hinfo->cfg.srcmask);
523
524 if (!(hinfo->cfg.mode &
525 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
526 return 0;
527 nexthdr = ip_hdr(skb)->protocol;
528 break;
529 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
530 case NFPROTO_IPV6:
531 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
532 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
533 sizeof(dst->ip6.dst));
534 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
535 }
536 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
537 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
538 sizeof(dst->ip6.src));
539 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
540 }
541
542 if (!(hinfo->cfg.mode &
543 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
544 return 0;
545 nexthdr = ipv6_hdr(skb)->nexthdr;
546 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
547 if ((int)protoff < 0)
548 return -1;
549 break;
550 #endif
551 default:
552 BUG();
553 return 0;
554 }
555
556 switch (nexthdr) {
557 case IPPROTO_TCP:
558 case IPPROTO_UDP:
559 case IPPROTO_UDPLITE:
560 case IPPROTO_SCTP:
561 case IPPROTO_DCCP:
562 ports = skb_header_pointer(skb, protoff, sizeof(_ports),
563 &_ports);
564 break;
565 default:
566 _ports[0] = _ports[1] = 0;
567 ports = _ports;
568 break;
569 }
570 if (!ports)
571 return -1;
572 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
573 dst->src_port = ports[0];
574 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
575 dst->dst_port = ports[1];
576 return 0;
577 }
578
579 static bool
580 hashlimit_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
581 {
582 const struct xt_hashlimit_info *r = par->matchinfo;
583 struct xt_hashlimit_htable *hinfo = r->hinfo;
584 unsigned long now = jiffies;
585 struct dsthash_ent *dh;
586 struct dsthash_dst dst;
587
588 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
589 goto hotdrop;
590
591 spin_lock_bh(&hinfo->lock);
592 dh = dsthash_find(hinfo, &dst);
593 if (!dh) {
594 dh = dsthash_alloc_init(hinfo, &dst);
595 if (!dh) {
596 spin_unlock_bh(&hinfo->lock);
597 goto hotdrop;
598 }
599
600 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
601 dh->rateinfo.prev = jiffies;
602 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
603 hinfo->cfg.burst);
604 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
605 hinfo->cfg.burst);
606 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
607 } else {
608 /* update expiration timeout */
609 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
610 rateinfo_recalc(dh, now);
611 }
612
613 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
614 /* We're underlimit. */
615 dh->rateinfo.credit -= dh->rateinfo.cost;
616 spin_unlock_bh(&hinfo->lock);
617 return true;
618 }
619
620 spin_unlock_bh(&hinfo->lock);
621
622 /* default case: we're overlimit, thus don't match */
623 return false;
624
625 hotdrop:
626 *par->hotdrop = true;
627 return false;
628 }
629
630 static bool
631 hashlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
632 {
633 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
634 struct xt_hashlimit_htable *hinfo = info->hinfo;
635 unsigned long now = jiffies;
636 struct dsthash_ent *dh;
637 struct dsthash_dst dst;
638
639 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
640 goto hotdrop;
641
642 spin_lock_bh(&hinfo->lock);
643 dh = dsthash_find(hinfo, &dst);
644 if (dh == NULL) {
645 dh = dsthash_alloc_init(hinfo, &dst);
646 if (dh == NULL) {
647 spin_unlock_bh(&hinfo->lock);
648 goto hotdrop;
649 }
650
651 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
652 dh->rateinfo.prev = jiffies;
653 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
654 hinfo->cfg.burst);
655 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
656 hinfo->cfg.burst);
657 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
658 } else {
659 /* update expiration timeout */
660 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
661 rateinfo_recalc(dh, now);
662 }
663
664 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
665 /* below the limit */
666 dh->rateinfo.credit -= dh->rateinfo.cost;
667 spin_unlock_bh(&hinfo->lock);
668 return !(info->cfg.mode & XT_HASHLIMIT_INVERT);
669 }
670
671 spin_unlock_bh(&hinfo->lock);
672 /* default match is underlimit - so over the limit, we need to invert */
673 return info->cfg.mode & XT_HASHLIMIT_INVERT;
674
675 hotdrop:
676 *par->hotdrop = true;
677 return false;
678 }
679
680 static bool hashlimit_mt_check_v0(const struct xt_mtchk_param *par)
681 {
682 struct net *net = par->net;
683 struct xt_hashlimit_info *r = par->matchinfo;
684
685 /* Check for overflow. */
686 if (r->cfg.burst == 0 ||
687 user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
688 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
689 r->cfg.avg, r->cfg.burst);
690 return false;
691 }
692 if (r->cfg.mode == 0 ||
693 r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
694 XT_HASHLIMIT_HASH_DIP |
695 XT_HASHLIMIT_HASH_SIP |
696 XT_HASHLIMIT_HASH_SPT))
697 return false;
698 if (!r->cfg.gc_interval)
699 return false;
700 if (!r->cfg.expire)
701 return false;
702 if (r->name[sizeof(r->name) - 1] != '\0')
703 return false;
704
705 mutex_lock(&hashlimit_mutex);
706 r->hinfo = htable_find_get(net, r->name, par->match->family);
707 if (!r->hinfo && htable_create_v0(net, r, par->match->family) != 0) {
708 mutex_unlock(&hashlimit_mutex);
709 return false;
710 }
711 mutex_unlock(&hashlimit_mutex);
712
713 return true;
714 }
715
716 static bool hashlimit_mt_check(const struct xt_mtchk_param *par)
717 {
718 struct net *net = par->net;
719 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
720
721 /* Check for overflow. */
722 if (info->cfg.burst == 0 ||
723 user2credits(info->cfg.avg * info->cfg.burst) <
724 user2credits(info->cfg.avg)) {
725 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
726 info->cfg.avg, info->cfg.burst);
727 return false;
728 }
729 if (info->cfg.gc_interval == 0 || info->cfg.expire == 0)
730 return false;
731 if (info->name[sizeof(info->name)-1] != '\0')
732 return false;
733 if (par->match->family == NFPROTO_IPV4) {
734 if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32)
735 return false;
736 } else {
737 if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128)
738 return false;
739 }
740
741 mutex_lock(&hashlimit_mutex);
742 info->hinfo = htable_find_get(net, info->name, par->match->family);
743 if (!info->hinfo && htable_create(net, info, par->match->family) != 0) {
744 mutex_unlock(&hashlimit_mutex);
745 return false;
746 }
747 mutex_unlock(&hashlimit_mutex);
748 return true;
749 }
750
751 static void
752 hashlimit_mt_destroy_v0(const struct xt_mtdtor_param *par)
753 {
754 const struct xt_hashlimit_info *r = par->matchinfo;
755
756 htable_put(r->hinfo);
757 }
758
759 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
760 {
761 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
762
763 htable_put(info->hinfo);
764 }
765
766 #ifdef CONFIG_COMPAT
767 struct compat_xt_hashlimit_info {
768 char name[IFNAMSIZ];
769 struct hashlimit_cfg cfg;
770 compat_uptr_t hinfo;
771 compat_uptr_t master;
772 };
773
774 static void hashlimit_mt_compat_from_user(void *dst, const void *src)
775 {
776 int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
777
778 memcpy(dst, src, off);
779 memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
780 }
781
782 static int hashlimit_mt_compat_to_user(void __user *dst, const void *src)
783 {
784 int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
785
786 return copy_to_user(dst, src, off) ? -EFAULT : 0;
787 }
788 #endif
789
790 static struct xt_match hashlimit_mt_reg[] __read_mostly = {
791 {
792 .name = "hashlimit",
793 .revision = 0,
794 .family = NFPROTO_IPV4,
795 .match = hashlimit_mt_v0,
796 .matchsize = sizeof(struct xt_hashlimit_info),
797 #ifdef CONFIG_COMPAT
798 .compatsize = sizeof(struct compat_xt_hashlimit_info),
799 .compat_from_user = hashlimit_mt_compat_from_user,
800 .compat_to_user = hashlimit_mt_compat_to_user,
801 #endif
802 .checkentry = hashlimit_mt_check_v0,
803 .destroy = hashlimit_mt_destroy_v0,
804 .me = THIS_MODULE
805 },
806 {
807 .name = "hashlimit",
808 .revision = 1,
809 .family = NFPROTO_IPV4,
810 .match = hashlimit_mt,
811 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
812 .checkentry = hashlimit_mt_check,
813 .destroy = hashlimit_mt_destroy,
814 .me = THIS_MODULE,
815 },
816 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
817 {
818 .name = "hashlimit",
819 .family = NFPROTO_IPV6,
820 .match = hashlimit_mt_v0,
821 .matchsize = sizeof(struct xt_hashlimit_info),
822 #ifdef CONFIG_COMPAT
823 .compatsize = sizeof(struct compat_xt_hashlimit_info),
824 .compat_from_user = hashlimit_mt_compat_from_user,
825 .compat_to_user = hashlimit_mt_compat_to_user,
826 #endif
827 .checkentry = hashlimit_mt_check_v0,
828 .destroy = hashlimit_mt_destroy_v0,
829 .me = THIS_MODULE
830 },
831 {
832 .name = "hashlimit",
833 .revision = 1,
834 .family = NFPROTO_IPV6,
835 .match = hashlimit_mt,
836 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
837 .checkentry = hashlimit_mt_check,
838 .destroy = hashlimit_mt_destroy,
839 .me = THIS_MODULE,
840 },
841 #endif
842 };
843
844 /* PROC stuff */
845 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
846 __acquires(htable->lock)
847 {
848 struct xt_hashlimit_htable *htable = s->private;
849 unsigned int *bucket;
850
851 spin_lock_bh(&htable->lock);
852 if (*pos >= htable->cfg.size)
853 return NULL;
854
855 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
856 if (!bucket)
857 return ERR_PTR(-ENOMEM);
858
859 *bucket = *pos;
860 return bucket;
861 }
862
863 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
864 {
865 struct xt_hashlimit_htable *htable = s->private;
866 unsigned int *bucket = (unsigned int *)v;
867
868 *pos = ++(*bucket);
869 if (*pos >= htable->cfg.size) {
870 kfree(v);
871 return NULL;
872 }
873 return bucket;
874 }
875
876 static void dl_seq_stop(struct seq_file *s, void *v)
877 __releases(htable->lock)
878 {
879 struct xt_hashlimit_htable *htable = s->private;
880 unsigned int *bucket = (unsigned int *)v;
881
882 kfree(bucket);
883 spin_unlock_bh(&htable->lock);
884 }
885
886 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
887 struct seq_file *s)
888 {
889 /* recalculate to show accurate numbers */
890 rateinfo_recalc(ent, jiffies);
891
892 switch (family) {
893 case NFPROTO_IPV4:
894 return seq_printf(s, "%ld %pI4:%u->%pI4:%u %u %u %u\n",
895 (long)(ent->expires - jiffies)/HZ,
896 &ent->dst.ip.src,
897 ntohs(ent->dst.src_port),
898 &ent->dst.ip.dst,
899 ntohs(ent->dst.dst_port),
900 ent->rateinfo.credit, ent->rateinfo.credit_cap,
901 ent->rateinfo.cost);
902 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
903 case NFPROTO_IPV6:
904 return seq_printf(s, "%ld %pI6:%u->%pI6:%u %u %u %u\n",
905 (long)(ent->expires - jiffies)/HZ,
906 &ent->dst.ip6.src,
907 ntohs(ent->dst.src_port),
908 &ent->dst.ip6.dst,
909 ntohs(ent->dst.dst_port),
910 ent->rateinfo.credit, ent->rateinfo.credit_cap,
911 ent->rateinfo.cost);
912 #endif
913 default:
914 BUG();
915 return 0;
916 }
917 }
918
919 static int dl_seq_show(struct seq_file *s, void *v)
920 {
921 struct xt_hashlimit_htable *htable = s->private;
922 unsigned int *bucket = (unsigned int *)v;
923 struct dsthash_ent *ent;
924 struct hlist_node *pos;
925
926 if (!hlist_empty(&htable->hash[*bucket])) {
927 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
928 if (dl_seq_real_show(ent, htable->family, s))
929 return -1;
930 }
931 return 0;
932 }
933
934 static const struct seq_operations dl_seq_ops = {
935 .start = dl_seq_start,
936 .next = dl_seq_next,
937 .stop = dl_seq_stop,
938 .show = dl_seq_show
939 };
940
941 static int dl_proc_open(struct inode *inode, struct file *file)
942 {
943 int ret = seq_open(file, &dl_seq_ops);
944
945 if (!ret) {
946 struct seq_file *sf = file->private_data;
947 sf->private = PDE(inode)->data;
948 }
949 return ret;
950 }
951
952 static const struct file_operations dl_file_ops = {
953 .owner = THIS_MODULE,
954 .open = dl_proc_open,
955 .read = seq_read,
956 .llseek = seq_lseek,
957 .release = seq_release
958 };
959
960 static int __net_init hashlimit_proc_net_init(struct net *net)
961 {
962 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
963
964 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
965 if (!hashlimit_net->ipt_hashlimit)
966 return -ENOMEM;
967 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
968 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
969 if (!hashlimit_net->ip6t_hashlimit) {
970 proc_net_remove(net, "ipt_hashlimit");
971 return -ENOMEM;
972 }
973 #endif
974 return 0;
975 }
976
977 static void __net_exit hashlimit_proc_net_exit(struct net *net)
978 {
979 proc_net_remove(net, "ipt_hashlimit");
980 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
981 proc_net_remove(net, "ip6t_hashlimit");
982 #endif
983 }
984
985 static int __net_init hashlimit_net_init(struct net *net)
986 {
987 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
988
989 INIT_HLIST_HEAD(&hashlimit_net->htables);
990 return hashlimit_proc_net_init(net);
991 }
992
993 static void __net_exit hashlimit_net_exit(struct net *net)
994 {
995 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
996
997 BUG_ON(!hlist_empty(&hashlimit_net->htables));
998 hashlimit_proc_net_exit(net);
999 }
1000
1001 static struct pernet_operations hashlimit_net_ops = {
1002 .init = hashlimit_net_init,
1003 .exit = hashlimit_net_exit,
1004 .id = &hashlimit_net_id,
1005 .size = sizeof(struct hashlimit_net),
1006 };
1007
1008 static int __init hashlimit_mt_init(void)
1009 {
1010 int err;
1011
1012 err = register_pernet_subsys(&hashlimit_net_ops);
1013 if (err < 0)
1014 return err;
1015 err = xt_register_matches(hashlimit_mt_reg,
1016 ARRAY_SIZE(hashlimit_mt_reg));
1017 if (err < 0)
1018 goto err1;
1019
1020 err = -ENOMEM;
1021 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
1022 sizeof(struct dsthash_ent), 0, 0,
1023 NULL);
1024 if (!hashlimit_cachep) {
1025 printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
1026 goto err2;
1027 }
1028 return 0;
1029
1030 err2:
1031 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1032 err1:
1033 unregister_pernet_subsys(&hashlimit_net_ops);
1034 return err;
1035
1036 }
1037
1038 static void __exit hashlimit_mt_exit(void)
1039 {
1040 kmem_cache_destroy(hashlimit_cachep);
1041 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1042 unregister_pernet_subsys(&hashlimit_net_ops);
1043 }
1044
1045 module_init(hashlimit_mt_init);
1046 module_exit(hashlimit_mt_exit);
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