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[linux-ginger.git] / net / netfilter / xt_hashlimit.c
blobdd16e404424fe7610449e8d95c1c809aada1af3f
1 /*
2 * xt_hashlimit - Netfilter module to limit the number of packets per time
3 * seperately 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
30 #include <linux/netfilter/x_tables.h>
31 #include <linux/netfilter_ipv4/ip_tables.h>
32 #include <linux/netfilter_ipv6/ip6_tables.h>
33 #include <linux/netfilter/xt_hashlimit.h>
34 #include <linux/mutex.h>
35
36 MODULE_LICENSE("GPL");
37 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
38 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
39 MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
40 MODULE_ALIAS("ipt_hashlimit");
41 MODULE_ALIAS("ip6t_hashlimit");
42
43 /* need to declare this at the top */
44 static struct proc_dir_entry *hashlimit_procdir4;
45 static struct proc_dir_entry *hashlimit_procdir6;
46 static const struct file_operations dl_file_ops;
47
48 /* hash table crap */
49 struct dsthash_dst {
50 union {
51 struct {
52 __be32 src;
53 __be32 dst;
54 } ip;
55 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
56 struct {
57 __be32 src[4];
58 __be32 dst[4];
59 } ip6;
60 #endif
61 };
62 __be16 src_port;
63 __be16 dst_port;
64 };
65
66 struct dsthash_ent {
67 /* static / read-only parts in the beginning */
68 struct hlist_node node;
69 struct dsthash_dst dst;
70
71 /* modified structure members in the end */
72 unsigned long expires; /* precalculated expiry time */
73 struct {
74 unsigned long prev; /* last modification */
75 u_int32_t credit;
76 u_int32_t credit_cap, cost;
77 } rateinfo;
78 };
79
80 struct xt_hashlimit_htable {
81 struct hlist_node node; /* global list of all htables */
82 atomic_t use;
83 u_int8_t family;
84
85 struct hashlimit_cfg1 cfg; /* config */
86
87 /* used internally */
88 spinlock_t lock; /* lock for list_head */
89 u_int32_t rnd; /* random seed for hash */
90 int rnd_initialized;
91 unsigned int count; /* number entries in table */
92 struct timer_list timer; /* timer for gc */
93
94 /* seq_file stuff */
95 struct proc_dir_entry *pde;
96
97 struct hlist_head hash[0]; /* hashtable itself */
98 };
99
100 static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */
101 static DEFINE_MUTEX(hlimit_mutex); /* additional checkentry protection */
102 static HLIST_HEAD(hashlimit_htables);
103 static struct kmem_cache *hashlimit_cachep __read_mostly;
104
105 static inline bool dst_cmp(const struct dsthash_ent *ent,
106 const struct dsthash_dst *b)
107 {
108 return !memcmp(&ent->dst, b, sizeof(ent->dst));
109 }
110
111 static u_int32_t
112 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
113 {
114 u_int32_t hash = jhash2((const u32 *)dst,
115 sizeof(*dst)/sizeof(u32),
116 ht->rnd);
117 /*
118 * Instead of returning hash % ht->cfg.size (implying a divide)
119 * we return the high 32 bits of the (hash * ht->cfg.size) that will
120 * give results between [0 and cfg.size-1] and same hash distribution,
121 * but using a multiply, less expensive than a divide
122 */
123 return ((u64)hash * ht->cfg.size) >> 32;
124 }
125
126 static struct dsthash_ent *
127 dsthash_find(const struct xt_hashlimit_htable *ht,
128 const struct dsthash_dst *dst)
129 {
130 struct dsthash_ent *ent;
131 struct hlist_node *pos;
132 u_int32_t hash = hash_dst(ht, dst);
133
134 if (!hlist_empty(&ht->hash[hash])) {
135 hlist_for_each_entry(ent, pos, &ht->hash[hash], node)
136 if (dst_cmp(ent, dst))
137 return ent;
138 }
139 return NULL;
140 }
141
142 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
143 static struct dsthash_ent *
144 dsthash_alloc_init(struct xt_hashlimit_htable *ht,
145 const struct dsthash_dst *dst)
146 {
147 struct dsthash_ent *ent;
148
149 /* initialize hash with random val at the time we allocate
150 * the first hashtable entry */
151 if (!ht->rnd_initialized) {
152 get_random_bytes(&ht->rnd, sizeof(ht->rnd));
153 ht->rnd_initialized = 1;
154 }
155
156 if (ht->cfg.max && ht->count >= ht->cfg.max) {
157 /* FIXME: do something. question is what.. */
158 if (net_ratelimit())
159 printk(KERN_WARNING
160 "xt_hashlimit: max count of %u reached\n",
161 ht->cfg.max);
162 return NULL;
163 }
164
165 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
166 if (!ent) {
167 if (net_ratelimit())
168 printk(KERN_ERR
169 "xt_hashlimit: can't allocate dsthash_ent\n");
170 return NULL;
171 }
172 memcpy(&ent->dst, dst, sizeof(ent->dst));
173
174 hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
175 ht->count++;
176 return ent;
177 }
178
179 static inline void
180 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
181 {
182 hlist_del(&ent->node);
183 kmem_cache_free(hashlimit_cachep, ent);
184 ht->count--;
185 }
186 static void htable_gc(unsigned long htlong);
187
188 static int htable_create_v0(struct xt_hashlimit_info *minfo, u_int8_t family)
189 {
190 struct xt_hashlimit_htable *hinfo;
191 unsigned int size;
192 unsigned int i;
193
194 if (minfo->cfg.size)
195 size = minfo->cfg.size;
196 else {
197 size = ((totalram_pages << PAGE_SHIFT) / 16384) /
198 sizeof(struct list_head);
199 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE))
200 size = 8192;
201 if (size < 16)
202 size = 16;
203 }
204 /* FIXME: don't use vmalloc() here or anywhere else -HW */
205 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
206 sizeof(struct list_head) * size);
207 if (!hinfo) {
208 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
209 return -1;
210 }
211 minfo->hinfo = hinfo;
212
213 /* copy match config into hashtable config */
214 hinfo->cfg.mode = minfo->cfg.mode;
215 hinfo->cfg.avg = minfo->cfg.avg;
216 hinfo->cfg.burst = minfo->cfg.burst;
217 hinfo->cfg.max = minfo->cfg.max;
218 hinfo->cfg.gc_interval = minfo->cfg.gc_interval;
219 hinfo->cfg.expire = minfo->cfg.expire;
220
221 if (family == NFPROTO_IPV4)
222 hinfo->cfg.srcmask = hinfo->cfg.dstmask = 32;
223 else
224 hinfo->cfg.srcmask = hinfo->cfg.dstmask = 128;
225
226 hinfo->cfg.size = size;
227 if (!hinfo->cfg.max)
228 hinfo->cfg.max = 8 * hinfo->cfg.size;
229 else if (hinfo->cfg.max < hinfo->cfg.size)
230 hinfo->cfg.max = hinfo->cfg.size;
231
232 for (i = 0; i < hinfo->cfg.size; i++)
233 INIT_HLIST_HEAD(&hinfo->hash[i]);
234
235 atomic_set(&hinfo->use, 1);
236 hinfo->count = 0;
237 hinfo->family = family;
238 hinfo->rnd_initialized = 0;
239 spin_lock_init(&hinfo->lock);
240 hinfo->pde = proc_create_data(minfo->name, 0,
241 (family == NFPROTO_IPV4) ?
242 hashlimit_procdir4 : hashlimit_procdir6,
243 &dl_file_ops, hinfo);
244 if (!hinfo->pde) {
245 vfree(hinfo);
246 return -1;
247 }
248
249 setup_timer(&hinfo->timer, htable_gc, (unsigned long )hinfo);
250 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
251 add_timer(&hinfo->timer);
252
253 spin_lock_bh(&hashlimit_lock);
254 hlist_add_head(&hinfo->node, &hashlimit_htables);
255 spin_unlock_bh(&hashlimit_lock);
256
257 return 0;
258 }
259
260 static int htable_create(struct xt_hashlimit_mtinfo1 *minfo, u_int8_t family)
261 {
262 struct xt_hashlimit_htable *hinfo;
263 unsigned int size;
264 unsigned int i;
265
266 if (minfo->cfg.size) {
267 size = minfo->cfg.size;
268 } else {
269 size = (totalram_pages << PAGE_SHIFT) / 16384 /
270 sizeof(struct list_head);
271 if (totalram_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
272 size = 8192;
273 if (size < 16)
274 size = 16;
275 }
276 /* FIXME: don't use vmalloc() here or anywhere else -HW */
277 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
278 sizeof(struct list_head) * size);
279 if (hinfo == NULL) {
280 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
281 return -1;
282 }
283 minfo->hinfo = hinfo;
284
285 /* copy match config into hashtable config */
286 memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
287 hinfo->cfg.size = size;
288 if (hinfo->cfg.max == 0)
289 hinfo->cfg.max = 8 * hinfo->cfg.size;
290 else if (hinfo->cfg.max < hinfo->cfg.size)
291 hinfo->cfg.max = hinfo->cfg.size;
292
293 for (i = 0; i < hinfo->cfg.size; i++)
294 INIT_HLIST_HEAD(&hinfo->hash[i]);
295
296 atomic_set(&hinfo->use, 1);
297 hinfo->count = 0;
298 hinfo->family = family;
299 hinfo->rnd_initialized = 0;
300 spin_lock_init(&hinfo->lock);
301
302 hinfo->pde = proc_create_data(minfo->name, 0,
303 (family == NFPROTO_IPV4) ?
304 hashlimit_procdir4 : hashlimit_procdir6,
305 &dl_file_ops, hinfo);
306 if (hinfo->pde == NULL) {
307 vfree(hinfo);
308 return -1;
309 }
310
311 setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo);
312 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
313 add_timer(&hinfo->timer);
314
315 spin_lock_bh(&hashlimit_lock);
316 hlist_add_head(&hinfo->node, &hashlimit_htables);
317 spin_unlock_bh(&hashlimit_lock);
318
319 return 0;
320 }
321
322 static bool select_all(const struct xt_hashlimit_htable *ht,
323 const struct dsthash_ent *he)
324 {
325 return 1;
326 }
327
328 static bool select_gc(const struct xt_hashlimit_htable *ht,
329 const struct dsthash_ent *he)
330 {
331 return time_after_eq(jiffies, he->expires);
332 }
333
334 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
335 bool (*select)(const struct xt_hashlimit_htable *ht,
336 const struct dsthash_ent *he))
337 {
338 unsigned int i;
339
340 /* lock hash table and iterate over it */
341 spin_lock_bh(&ht->lock);
342 for (i = 0; i < ht->cfg.size; i++) {
343 struct dsthash_ent *dh;
344 struct hlist_node *pos, *n;
345 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
346 if ((*select)(ht, dh))
347 dsthash_free(ht, dh);
348 }
349 }
350 spin_unlock_bh(&ht->lock);
351 }
352
353 /* hash table garbage collector, run by timer */
354 static void htable_gc(unsigned long htlong)
355 {
356 struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
357
358 htable_selective_cleanup(ht, select_gc);
359
360 /* re-add the timer accordingly */
361 ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
362 add_timer(&ht->timer);
363 }
364
365 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
366 {
367 del_timer_sync(&hinfo->timer);
368
369 /* remove proc entry */
370 remove_proc_entry(hinfo->pde->name,
371 hinfo->family == NFPROTO_IPV4 ? hashlimit_procdir4 :
372 hashlimit_procdir6);
373 htable_selective_cleanup(hinfo, select_all);
374 vfree(hinfo);
375 }
376
377 static struct xt_hashlimit_htable *htable_find_get(const char *name,
378 u_int8_t family)
379 {
380 struct xt_hashlimit_htable *hinfo;
381 struct hlist_node *pos;
382
383 spin_lock_bh(&hashlimit_lock);
384 hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
385 if (!strcmp(name, hinfo->pde->name) &&
386 hinfo->family == family) {
387 atomic_inc(&hinfo->use);
388 spin_unlock_bh(&hashlimit_lock);
389 return hinfo;
390 }
391 }
392 spin_unlock_bh(&hashlimit_lock);
393 return NULL;
394 }
395
396 static void htable_put(struct xt_hashlimit_htable *hinfo)
397 {
398 if (atomic_dec_and_test(&hinfo->use)) {
399 spin_lock_bh(&hashlimit_lock);
400 hlist_del(&hinfo->node);
401 spin_unlock_bh(&hashlimit_lock);
402 htable_destroy(hinfo);
403 }
404 }
405
406 /* The algorithm used is the Simple Token Bucket Filter (TBF)
407 * see net/sched/sch_tbf.c in the linux source tree
408 */
409
410 /* Rusty: This is my (non-mathematically-inclined) understanding of
411 this algorithm. The `average rate' in jiffies becomes your initial
412 amount of credit `credit' and the most credit you can ever have
413 `credit_cap'. The `peak rate' becomes the cost of passing the
414 test, `cost'.
415
416 `prev' tracks the last packet hit: you gain one credit per jiffy.
417 If you get credit balance more than this, the extra credit is
418 discarded. Every time the match passes, you lose `cost' credits;
419 if you don't have that many, the test fails.
420
421 See Alexey's formal explanation in net/sched/sch_tbf.c.
422
423 To get the maximum range, we multiply by this factor (ie. you get N
424 credits per jiffy). We want to allow a rate as low as 1 per day
425 (slowest userspace tool allows), which means
426 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
427 */
428 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
429
430 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
431 * us the power of 2 below the theoretical max, so GCC simply does a
432 * shift. */
433 #define _POW2_BELOW2(x) ((x)|((x)>>1))
434 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
435 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
436 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
437 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
438 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
439
440 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
441
442 /* Precision saver. */
443 static inline u_int32_t
444 user2credits(u_int32_t user)
445 {
446 /* If multiplying would overflow... */
447 if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
448 /* Divide first. */
449 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
450
451 return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
452 }
453
454 static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
455 {
456 dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
457 if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
458 dh->rateinfo.credit = dh->rateinfo.credit_cap;
459 dh->rateinfo.prev = now;
460 }
461
462 static inline __be32 maskl(__be32 a, unsigned int l)
463 {
464 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
465 }
466
467 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
468 static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
469 {
470 switch (p) {
471 case 0 ... 31:
472 i[0] = maskl(i[0], p);
473 i[1] = i[2] = i[3] = 0;
474 break;
475 case 32 ... 63:
476 i[1] = maskl(i[1], p - 32);
477 i[2] = i[3] = 0;
478 break;
479 case 64 ... 95:
480 i[2] = maskl(i[2], p - 64);
481 i[3] = 0;
482 case 96 ... 127:
483 i[3] = maskl(i[3], p - 96);
484 break;
485 case 128:
486 break;
487 }
488 }
489 #endif
490
491 static int
492 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
493 struct dsthash_dst *dst,
494 const struct sk_buff *skb, unsigned int protoff)
495 {
496 __be16 _ports[2], *ports;
497 u8 nexthdr;
498
499 memset(dst, 0, sizeof(*dst));
500
501 switch (hinfo->family) {
502 case NFPROTO_IPV4:
503 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
504 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
505 hinfo->cfg.dstmask);
506 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
507 dst->ip.src = maskl(ip_hdr(skb)->saddr,
508 hinfo->cfg.srcmask);
509
510 if (!(hinfo->cfg.mode &
511 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
512 return 0;
513 nexthdr = ip_hdr(skb)->protocol;
514 break;
515 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
516 case NFPROTO_IPV6:
517 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
518 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
519 sizeof(dst->ip6.dst));
520 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
521 }
522 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
523 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
524 sizeof(dst->ip6.src));
525 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
526 }
527
528 if (!(hinfo->cfg.mode &
529 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
530 return 0;
531 nexthdr = ipv6_hdr(skb)->nexthdr;
532 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
533 if ((int)protoff < 0)
534 return -1;
535 break;
536 #endif
537 default:
538 BUG();
539 return 0;
540 }
541
542 switch (nexthdr) {
543 case IPPROTO_TCP:
544 case IPPROTO_UDP:
545 case IPPROTO_UDPLITE:
546 case IPPROTO_SCTP:
547 case IPPROTO_DCCP:
548 ports = skb_header_pointer(skb, protoff, sizeof(_ports),
549 &_ports);
550 break;
551 default:
552 _ports[0] = _ports[1] = 0;
553 ports = _ports;
554 break;
555 }
556 if (!ports)
557 return -1;
558 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
559 dst->src_port = ports[0];
560 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
561 dst->dst_port = ports[1];
562 return 0;
563 }
564
565 static bool
566 hashlimit_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
567 {
568 const struct xt_hashlimit_info *r = par->matchinfo;
569 struct xt_hashlimit_htable *hinfo = r->hinfo;
570 unsigned long now = jiffies;
571 struct dsthash_ent *dh;
572 struct dsthash_dst dst;
573
574 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
575 goto hotdrop;
576
577 spin_lock_bh(&hinfo->lock);
578 dh = dsthash_find(hinfo, &dst);
579 if (!dh) {
580 dh = dsthash_alloc_init(hinfo, &dst);
581 if (!dh) {
582 spin_unlock_bh(&hinfo->lock);
583 goto hotdrop;
584 }
585
586 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
587 dh->rateinfo.prev = jiffies;
588 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
589 hinfo->cfg.burst);
590 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
591 hinfo->cfg.burst);
592 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
593 } else {
594 /* update expiration timeout */
595 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
596 rateinfo_recalc(dh, now);
597 }
598
599 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
600 /* We're underlimit. */
601 dh->rateinfo.credit -= dh->rateinfo.cost;
602 spin_unlock_bh(&hinfo->lock);
603 return true;
604 }
605
606 spin_unlock_bh(&hinfo->lock);
607
608 /* default case: we're overlimit, thus don't match */
609 return false;
610
611 hotdrop:
612 *par->hotdrop = true;
613 return false;
614 }
615
616 static bool
617 hashlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
618 {
619 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
620 struct xt_hashlimit_htable *hinfo = info->hinfo;
621 unsigned long now = jiffies;
622 struct dsthash_ent *dh;
623 struct dsthash_dst dst;
624
625 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
626 goto hotdrop;
627
628 spin_lock_bh(&hinfo->lock);
629 dh = dsthash_find(hinfo, &dst);
630 if (dh == NULL) {
631 dh = dsthash_alloc_init(hinfo, &dst);
632 if (dh == NULL) {
633 spin_unlock_bh(&hinfo->lock);
634 goto hotdrop;
635 }
636
637 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
638 dh->rateinfo.prev = jiffies;
639 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
640 hinfo->cfg.burst);
641 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
642 hinfo->cfg.burst);
643 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
644 } else {
645 /* update expiration timeout */
646 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
647 rateinfo_recalc(dh, now);
648 }
649
650 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
651 /* below the limit */
652 dh->rateinfo.credit -= dh->rateinfo.cost;
653 spin_unlock_bh(&hinfo->lock);
654 return !(info->cfg.mode & XT_HASHLIMIT_INVERT);
655 }
656
657 spin_unlock_bh(&hinfo->lock);
658 /* default match is underlimit - so over the limit, we need to invert */
659 return info->cfg.mode & XT_HASHLIMIT_INVERT;
660
661 hotdrop:
662 *par->hotdrop = true;
663 return false;
664 }
665
666 static bool hashlimit_mt_check_v0(const struct xt_mtchk_param *par)
667 {
668 struct xt_hashlimit_info *r = par->matchinfo;
669
670 /* Check for overflow. */
671 if (r->cfg.burst == 0 ||
672 user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
673 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
674 r->cfg.avg, r->cfg.burst);
675 return false;
676 }
677 if (r->cfg.mode == 0 ||
678 r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
679 XT_HASHLIMIT_HASH_DIP |
680 XT_HASHLIMIT_HASH_SIP |
681 XT_HASHLIMIT_HASH_SPT))
682 return false;
683 if (!r->cfg.gc_interval)
684 return false;
685 if (!r->cfg.expire)
686 return false;
687 if (r->name[sizeof(r->name) - 1] != '\0')
688 return false;
689
690 /* This is the best we've got: We cannot release and re-grab lock,
691 * since checkentry() is called before x_tables.c grabs xt_mutex.
692 * We also cannot grab the hashtable spinlock, since htable_create will
693 * call vmalloc, and that can sleep. And we cannot just re-search
694 * the list of htable's in htable_create(), since then we would
695 * create duplicate proc files. -HW */
696 mutex_lock(&hlimit_mutex);
697 r->hinfo = htable_find_get(r->name, par->match->family);
698 if (!r->hinfo && htable_create_v0(r, par->match->family) != 0) {
699 mutex_unlock(&hlimit_mutex);
700 return false;
701 }
702 mutex_unlock(&hlimit_mutex);
703
704 return true;
705 }
706
707 static bool hashlimit_mt_check(const struct xt_mtchk_param *par)
708 {
709 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
710
711 /* Check for overflow. */
712 if (info->cfg.burst == 0 ||
713 user2credits(info->cfg.avg * info->cfg.burst) <
714 user2credits(info->cfg.avg)) {
715 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
716 info->cfg.avg, info->cfg.burst);
717 return false;
718 }
719 if (info->cfg.gc_interval == 0 || info->cfg.expire == 0)
720 return false;
721 if (info->name[sizeof(info->name)-1] != '\0')
722 return false;
723 if (par->match->family == NFPROTO_IPV4) {
724 if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32)
725 return false;
726 } else {
727 if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128)
728 return false;
729 }
730
731 /* This is the best we've got: We cannot release and re-grab lock,
732 * since checkentry() is called before x_tables.c grabs xt_mutex.
733 * We also cannot grab the hashtable spinlock, since htable_create will
734 * call vmalloc, and that can sleep. And we cannot just re-search
735 * the list of htable's in htable_create(), since then we would
736 * create duplicate proc files. -HW */
737 mutex_lock(&hlimit_mutex);
738 info->hinfo = htable_find_get(info->name, par->match->family);
739 if (!info->hinfo && htable_create(info, par->match->family) != 0) {
740 mutex_unlock(&hlimit_mutex);
741 return false;
742 }
743 mutex_unlock(&hlimit_mutex);
744 return true;
745 }
746
747 static void
748 hashlimit_mt_destroy_v0(const struct xt_mtdtor_param *par)
749 {
750 const struct xt_hashlimit_info *r = par->matchinfo;
751
752 htable_put(r->hinfo);
753 }
754
755 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
756 {
757 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
758
759 htable_put(info->hinfo);
760 }
761
762 #ifdef CONFIG_COMPAT
763 struct compat_xt_hashlimit_info {
764 char name[IFNAMSIZ];
765 struct hashlimit_cfg cfg;
766 compat_uptr_t hinfo;
767 compat_uptr_t master;
768 };
769
770 static void hashlimit_mt_compat_from_user(void *dst, void *src)
771 {
772 int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
773
774 memcpy(dst, src, off);
775 memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
776 }
777
778 static int hashlimit_mt_compat_to_user(void __user *dst, void *src)
779 {
780 int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
781
782 return copy_to_user(dst, src, off) ? -EFAULT : 0;
783 }
784 #endif
785
786 static struct xt_match hashlimit_mt_reg[] __read_mostly = {
787 {
788 .name = "hashlimit",
789 .revision = 0,
790 .family = NFPROTO_IPV4,
791 .match = hashlimit_mt_v0,
792 .matchsize = sizeof(struct xt_hashlimit_info),
793 #ifdef CONFIG_COMPAT
794 .compatsize = sizeof(struct compat_xt_hashlimit_info),
795 .compat_from_user = hashlimit_mt_compat_from_user,
796 .compat_to_user = hashlimit_mt_compat_to_user,
797 #endif
798 .checkentry = hashlimit_mt_check_v0,
799 .destroy = hashlimit_mt_destroy_v0,
800 .me = THIS_MODULE
801 },
802 {
803 .name = "hashlimit",
804 .revision = 1,
805 .family = NFPROTO_IPV4,
806 .match = hashlimit_mt,
807 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
808 .checkentry = hashlimit_mt_check,
809 .destroy = hashlimit_mt_destroy,
810 .me = THIS_MODULE,
811 },
812 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
813 {
814 .name = "hashlimit",
815 .family = NFPROTO_IPV6,
816 .match = hashlimit_mt_v0,
817 .matchsize = sizeof(struct xt_hashlimit_info),
818 #ifdef CONFIG_COMPAT
819 .compatsize = sizeof(struct compat_xt_hashlimit_info),
820 .compat_from_user = hashlimit_mt_compat_from_user,
821 .compat_to_user = hashlimit_mt_compat_to_user,
822 #endif
823 .checkentry = hashlimit_mt_check_v0,
824 .destroy = hashlimit_mt_destroy_v0,
825 .me = THIS_MODULE
826 },
827 {
828 .name = "hashlimit",
829 .revision = 1,
830 .family = NFPROTO_IPV6,
831 .match = hashlimit_mt,
832 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
833 .checkentry = hashlimit_mt_check,
834 .destroy = hashlimit_mt_destroy,
835 .me = THIS_MODULE,
836 },
837 #endif
838 };
839
840 /* PROC stuff */
841 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
842 __acquires(htable->lock)
843 {
844 struct proc_dir_entry *pde = s->private;
845 struct xt_hashlimit_htable *htable = pde->data;
846 unsigned int *bucket;
847
848 spin_lock_bh(&htable->lock);
849 if (*pos >= htable->cfg.size)
850 return NULL;
851
852 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
853 if (!bucket)
854 return ERR_PTR(-ENOMEM);
855
856 *bucket = *pos;
857 return bucket;
858 }
859
860 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
861 {
862 struct proc_dir_entry *pde = s->private;
863 struct xt_hashlimit_htable *htable = pde->data;
864 unsigned int *bucket = (unsigned int *)v;
865
866 *pos = ++(*bucket);
867 if (*pos >= htable->cfg.size) {
868 kfree(v);
869 return NULL;
870 }
871 return bucket;
872 }
873
874 static void dl_seq_stop(struct seq_file *s, void *v)
875 __releases(htable->lock)
876 {
877 struct proc_dir_entry *pde = s->private;
878 struct xt_hashlimit_htable *htable = pde->data;
879 unsigned int *bucket = (unsigned int *)v;
880
881 kfree(bucket);
882 spin_unlock_bh(&htable->lock);
883 }
884
885 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
886 struct seq_file *s)
887 {
888 /* recalculate to show accurate numbers */
889 rateinfo_recalc(ent, jiffies);
890
891 switch (family) {
892 case NFPROTO_IPV4:
893 return seq_printf(s, "%ld %pI4:%u->%pI4:%u %u %u %u\n",
894 (long)(ent->expires - jiffies)/HZ,
895 &ent->dst.ip.src,
896 ntohs(ent->dst.src_port),
897 &ent->dst.ip.dst,
898 ntohs(ent->dst.dst_port),
899 ent->rateinfo.credit, ent->rateinfo.credit_cap,
900 ent->rateinfo.cost);
901 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
902 case NFPROTO_IPV6:
903 return seq_printf(s, "%ld %pI6:%u->%pI6:%u %u %u %u\n",
904 (long)(ent->expires - jiffies)/HZ,
905 &ent->dst.ip6.src,
906 ntohs(ent->dst.src_port),
907 &ent->dst.ip6.dst,
908 ntohs(ent->dst.dst_port),
909 ent->rateinfo.credit, ent->rateinfo.credit_cap,
910 ent->rateinfo.cost);
911 #endif
912 default:
913 BUG();
914 return 0;
915 }
916 }
917
918 static int dl_seq_show(struct seq_file *s, void *v)
919 {
920 struct proc_dir_entry *pde = s->private;
921 struct xt_hashlimit_htable *htable = pde->data;
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);
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 __init hashlimit_mt_init(void)
961 {
962 int err;
963
964 err = xt_register_matches(hashlimit_mt_reg,
965 ARRAY_SIZE(hashlimit_mt_reg));
966 if (err < 0)
967 goto err1;
968
969 err = -ENOMEM;
970 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
971 sizeof(struct dsthash_ent), 0, 0,
972 NULL);
973 if (!hashlimit_cachep) {
974 printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
975 goto err2;
976 }
977 hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", init_net.proc_net);
978 if (!hashlimit_procdir4) {
979 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
980 "entry\n");
981 goto err3;
982 }
983 err = 0;
984 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
985 hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", init_net.proc_net);
986 if (!hashlimit_procdir6) {
987 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
988 "entry\n");
989 err = -ENOMEM;
990 }
991 #endif
992 if (!err)
993 return 0;
994 remove_proc_entry("ipt_hashlimit", init_net.proc_net);
995 err3:
996 kmem_cache_destroy(hashlimit_cachep);
997 err2:
998 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
999 err1:
1000 return err;
1001
1002 }
1003
1004 static void __exit hashlimit_mt_exit(void)
1005 {
1006 remove_proc_entry("ipt_hashlimit", init_net.proc_net);
1007 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
1008 remove_proc_entry("ip6t_hashlimit", init_net.proc_net);
1009 #endif
1010 kmem_cache_destroy(hashlimit_cachep);
1011 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1012 }
1013
1014 module_init(hashlimit_mt_init);
1015 module_exit(hashlimit_mt_exit);
Linux for Ginger Game Console