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cipso: unsigned buf_len cannot be negative
[linux-2.6/next.git] / net / netfilter / xt_hashlimit.c
blob6fc4292d46e6b33e18863878285af99ef34af3e7
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, 4);
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 = ((num_physpages << PAGE_SHIFT) / 16384) /
198 sizeof(struct list_head);
199 if (num_physpages > (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 = (num_physpages << PAGE_SHIFT) / 16384 /
270 sizeof(struct list_head);
271 if (num_physpages > 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 =
569 ((const struct xt_hashlimit_info *)par->matchinfo)->u.master;
570 struct xt_hashlimit_htable *hinfo = r->hinfo;
571 unsigned long now = jiffies;
572 struct dsthash_ent *dh;
573 struct dsthash_dst dst;
574
575 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
576 goto hotdrop;
577
578 spin_lock_bh(&hinfo->lock);
579 dh = dsthash_find(hinfo, &dst);
580 if (!dh) {
581 dh = dsthash_alloc_init(hinfo, &dst);
582 if (!dh) {
583 spin_unlock_bh(&hinfo->lock);
584 goto hotdrop;
585 }
586
587 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
588 dh->rateinfo.prev = jiffies;
589 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
590 hinfo->cfg.burst);
591 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
592 hinfo->cfg.burst);
593 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
594 } else {
595 /* update expiration timeout */
596 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
597 rateinfo_recalc(dh, now);
598 }
599
600 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
601 /* We're underlimit. */
602 dh->rateinfo.credit -= dh->rateinfo.cost;
603 spin_unlock_bh(&hinfo->lock);
604 return true;
605 }
606
607 spin_unlock_bh(&hinfo->lock);
608
609 /* default case: we're overlimit, thus don't match */
610 return false;
611
612 hotdrop:
613 *par->hotdrop = true;
614 return false;
615 }
616
617 static bool
618 hashlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
619 {
620 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
621 struct xt_hashlimit_htable *hinfo = info->hinfo;
622 unsigned long now = jiffies;
623 struct dsthash_ent *dh;
624 struct dsthash_dst dst;
625
626 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
627 goto hotdrop;
628
629 spin_lock_bh(&hinfo->lock);
630 dh = dsthash_find(hinfo, &dst);
631 if (dh == NULL) {
632 dh = dsthash_alloc_init(hinfo, &dst);
633 if (dh == NULL) {
634 spin_unlock_bh(&hinfo->lock);
635 goto hotdrop;
636 }
637
638 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
639 dh->rateinfo.prev = jiffies;
640 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
641 hinfo->cfg.burst);
642 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
643 hinfo->cfg.burst);
644 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
645 } else {
646 /* update expiration timeout */
647 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
648 rateinfo_recalc(dh, now);
649 }
650
651 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
652 /* below the limit */
653 dh->rateinfo.credit -= dh->rateinfo.cost;
654 spin_unlock_bh(&hinfo->lock);
655 return !(info->cfg.mode & XT_HASHLIMIT_INVERT);
656 }
657
658 spin_unlock_bh(&hinfo->lock);
659 /* default match is underlimit - so over the limit, we need to invert */
660 return info->cfg.mode & XT_HASHLIMIT_INVERT;
661
662 hotdrop:
663 *par->hotdrop = true;
664 return false;
665 }
666
667 static bool hashlimit_mt_check_v0(const struct xt_mtchk_param *par)
668 {
669 struct xt_hashlimit_info *r = par->matchinfo;
670
671 /* Check for overflow. */
672 if (r->cfg.burst == 0 ||
673 user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
674 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
675 r->cfg.avg, r->cfg.burst);
676 return false;
677 }
678 if (r->cfg.mode == 0 ||
679 r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
680 XT_HASHLIMIT_HASH_DIP |
681 XT_HASHLIMIT_HASH_SIP |
682 XT_HASHLIMIT_HASH_SPT))
683 return false;
684 if (!r->cfg.gc_interval)
685 return false;
686 if (!r->cfg.expire)
687 return false;
688 if (r->name[sizeof(r->name) - 1] != '\0')
689 return false;
690
691 /* This is the best we've got: We cannot release and re-grab lock,
692 * since checkentry() is called before x_tables.c grabs xt_mutex.
693 * We also cannot grab the hashtable spinlock, since htable_create will
694 * call vmalloc, and that can sleep. And we cannot just re-search
695 * the list of htable's in htable_create(), since then we would
696 * create duplicate proc files. -HW */
697 mutex_lock(&hlimit_mutex);
698 r->hinfo = htable_find_get(r->name, par->match->family);
699 if (!r->hinfo && htable_create_v0(r, par->match->family) != 0) {
700 mutex_unlock(&hlimit_mutex);
701 return false;
702 }
703 mutex_unlock(&hlimit_mutex);
704
705 /* Ugly hack: For SMP, we only want to use one set */
706 r->u.master = r;
707 return true;
708 }
709
710 static bool hashlimit_mt_check(const struct xt_mtchk_param *par)
711 {
712 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
713
714 /* Check for overflow. */
715 if (info->cfg.burst == 0 ||
716 user2credits(info->cfg.avg * info->cfg.burst) <
717 user2credits(info->cfg.avg)) {
718 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
719 info->cfg.avg, info->cfg.burst);
720 return false;
721 }
722 if (info->cfg.gc_interval == 0 || info->cfg.expire == 0)
723 return false;
724 if (info->name[sizeof(info->name)-1] != '\0')
725 return false;
726 if (par->match->family == NFPROTO_IPV4) {
727 if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32)
728 return false;
729 } else {
730 if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128)
731 return false;
732 }
733
734 /* This is the best we've got: We cannot release and re-grab lock,
735 * since checkentry() is called before x_tables.c grabs xt_mutex.
736 * We also cannot grab the hashtable spinlock, since htable_create will
737 * call vmalloc, and that can sleep. And we cannot just re-search
738 * the list of htable's in htable_create(), since then we would
739 * create duplicate proc files. -HW */
740 mutex_lock(&hlimit_mutex);
741 info->hinfo = htable_find_get(info->name, par->match->family);
742 if (!info->hinfo && htable_create(info, par->match->family) != 0) {
743 mutex_unlock(&hlimit_mutex);
744 return false;
745 }
746 mutex_unlock(&hlimit_mutex);
747 return true;
748 }
749
750 static void
751 hashlimit_mt_destroy_v0(const struct xt_mtdtor_param *par)
752 {
753 const struct xt_hashlimit_info *r = par->matchinfo;
754
755 htable_put(r->hinfo);
756 }
757
758 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
759 {
760 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
761
762 htable_put(info->hinfo);
763 }
764
765 #ifdef CONFIG_COMPAT
766 struct compat_xt_hashlimit_info {
767 char name[IFNAMSIZ];
768 struct hashlimit_cfg cfg;
769 compat_uptr_t hinfo;
770 compat_uptr_t master;
771 };
772
773 static void hashlimit_mt_compat_from_user(void *dst, void *src)
774 {
775 int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
776
777 memcpy(dst, src, off);
778 memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
779 }
780
781 static int hashlimit_mt_compat_to_user(void __user *dst, void *src)
782 {
783 int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
784
785 return copy_to_user(dst, src, off) ? -EFAULT : 0;
786 }
787 #endif
788
789 static struct xt_match hashlimit_mt_reg[] __read_mostly = {
790 {
791 .name = "hashlimit",
792 .revision = 0,
793 .family = NFPROTO_IPV4,
794 .match = hashlimit_mt_v0,
795 .matchsize = sizeof(struct xt_hashlimit_info),
796 #ifdef CONFIG_COMPAT
797 .compatsize = sizeof(struct compat_xt_hashlimit_info),
798 .compat_from_user = hashlimit_mt_compat_from_user,
799 .compat_to_user = hashlimit_mt_compat_to_user,
800 #endif
801 .checkentry = hashlimit_mt_check_v0,
802 .destroy = hashlimit_mt_destroy_v0,
803 .me = THIS_MODULE
804 },
805 {
806 .name = "hashlimit",
807 .revision = 1,
808 .family = NFPROTO_IPV4,
809 .match = hashlimit_mt,
810 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
811 .checkentry = hashlimit_mt_check,
812 .destroy = hashlimit_mt_destroy,
813 .me = THIS_MODULE,
814 },
815 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
816 {
817 .name = "hashlimit",
818 .family = NFPROTO_IPV6,
819 .match = hashlimit_mt_v0,
820 .matchsize = sizeof(struct xt_hashlimit_info),
821 #ifdef CONFIG_COMPAT
822 .compatsize = sizeof(struct compat_xt_hashlimit_info),
823 .compat_from_user = hashlimit_mt_compat_from_user,
824 .compat_to_user = hashlimit_mt_compat_to_user,
825 #endif
826 .checkentry = hashlimit_mt_check_v0,
827 .destroy = hashlimit_mt_destroy_v0,
828 .me = THIS_MODULE
829 },
830 {
831 .name = "hashlimit",
832 .revision = 1,
833 .family = NFPROTO_IPV6,
834 .match = hashlimit_mt,
835 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
836 .checkentry = hashlimit_mt_check,
837 .destroy = hashlimit_mt_destroy,
838 .me = THIS_MODULE,
839 },
840 #endif
841 };
842
843 /* PROC stuff */
844 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
845 __acquires(htable->lock)
846 {
847 struct proc_dir_entry *pde = s->private;
848 struct xt_hashlimit_htable *htable = pde->data;
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 proc_dir_entry *pde = s->private;
866 struct xt_hashlimit_htable *htable = pde->data;
867 unsigned int *bucket = (unsigned int *)v;
868
869 *pos = ++(*bucket);
870 if (*pos >= htable->cfg.size) {
871 kfree(v);
872 return NULL;
873 }
874 return bucket;
875 }
876
877 static void dl_seq_stop(struct seq_file *s, void *v)
878 __releases(htable->lock)
879 {
880 struct proc_dir_entry *pde = s->private;
881 struct xt_hashlimit_htable *htable = pde->data;
882 unsigned int *bucket = (unsigned int *)v;
883
884 kfree(bucket);
885 spin_unlock_bh(&htable->lock);
886 }
887
888 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
889 struct seq_file *s)
890 {
891 /* recalculate to show accurate numbers */
892 rateinfo_recalc(ent, jiffies);
893
894 switch (family) {
895 case NFPROTO_IPV4:
896 return seq_printf(s, "%ld %u.%u.%u.%u:%u->"
897 "%u.%u.%u.%u:%u %u %u %u\n",
898 (long)(ent->expires - jiffies)/HZ,
899 NIPQUAD(ent->dst.ip.src),
900 ntohs(ent->dst.src_port),
901 NIPQUAD(ent->dst.ip.dst),
902 ntohs(ent->dst.dst_port),
903 ent->rateinfo.credit, ent->rateinfo.credit_cap,
904 ent->rateinfo.cost);
905 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
906 case NFPROTO_IPV6:
907 return seq_printf(s, "%ld " NIP6_FMT ":%u->"
908 NIP6_FMT ":%u %u %u %u\n",
909 (long)(ent->expires - jiffies)/HZ,
910 NIP6(*(struct in6_addr *)&ent->dst.ip6.src),
911 ntohs(ent->dst.src_port),
912 NIP6(*(struct in6_addr *)&ent->dst.ip6.dst),
913 ntohs(ent->dst.dst_port),
914 ent->rateinfo.credit, ent->rateinfo.credit_cap,
915 ent->rateinfo.cost);
916 #endif
917 default:
918 BUG();
919 return 0;
920 }
921 }
922
923 static int dl_seq_show(struct seq_file *s, void *v)
924 {
925 struct proc_dir_entry *pde = s->private;
926 struct xt_hashlimit_htable *htable = pde->data;
927 unsigned int *bucket = (unsigned int *)v;
928 struct dsthash_ent *ent;
929 struct hlist_node *pos;
930
931 if (!hlist_empty(&htable->hash[*bucket])) {
932 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
933 if (dl_seq_real_show(ent, htable->family, s))
934 return 1;
935 }
936 return 0;
937 }
938
939 static const struct seq_operations dl_seq_ops = {
940 .start = dl_seq_start,
941 .next = dl_seq_next,
942 .stop = dl_seq_stop,
943 .show = dl_seq_show
944 };
945
946 static int dl_proc_open(struct inode *inode, struct file *file)
947 {
948 int ret = seq_open(file, &dl_seq_ops);
949
950 if (!ret) {
951 struct seq_file *sf = file->private_data;
952 sf->private = PDE(inode);
953 }
954 return ret;
955 }
956
957 static const struct file_operations dl_file_ops = {
958 .owner = THIS_MODULE,
959 .open = dl_proc_open,
960 .read = seq_read,
961 .llseek = seq_lseek,
962 .release = seq_release
963 };
964
965 static int __init hashlimit_mt_init(void)
966 {
967 int err;
968
969 err = xt_register_matches(hashlimit_mt_reg,
970 ARRAY_SIZE(hashlimit_mt_reg));
971 if (err < 0)
972 goto err1;
973
974 err = -ENOMEM;
975 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
976 sizeof(struct dsthash_ent), 0, 0,
977 NULL);
978 if (!hashlimit_cachep) {
979 printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
980 goto err2;
981 }
982 hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", init_net.proc_net);
983 if (!hashlimit_procdir4) {
984 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
985 "entry\n");
986 goto err3;
987 }
988 err = 0;
989 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
990 hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", init_net.proc_net);
991 if (!hashlimit_procdir6) {
992 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
993 "entry\n");
994 err = -ENOMEM;
995 }
996 #endif
997 if (!err)
998 return 0;
999 remove_proc_entry("ipt_hashlimit", init_net.proc_net);
1000 err3:
1001 kmem_cache_destroy(hashlimit_cachep);
1002 err2:
1003 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1004 err1:
1005 return err;
1006
1007 }
1008
1009 static void __exit hashlimit_mt_exit(void)
1010 {
1011 remove_proc_entry("ipt_hashlimit", init_net.proc_net);
1012 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
1013 remove_proc_entry("ip6t_hashlimit", init_net.proc_net);
1014 #endif
1015 kmem_cache_destroy(hashlimit_cachep);
1016 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1017 }
1018
1019 module_init(hashlimit_mt_init);
1020 module_exit(hashlimit_mt_exit);
linux-next