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[PATCH] memory hotadd fixes: not-aligned memory hotadd handling fix
[linux-2.6/kmemtrace.git] / net / ipv4 / netfilter / ipt_hashlimit.c
blob6b662449e8253579fc9e87112590d1ac55f7e238
1 /* iptables match extension to limit the number of packets per second
2 * seperately for each hashbucket (sourceip/sourceport/dstip/dstport)
3 *
4 * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
5 *
6 * $Id: ipt_hashlimit.c 3244 2004-10-20 16:24:29Z laforge@netfilter.org $
7 *
8 * Development of this code was funded by Astaro AG, http://www.astaro.com/
9 *
10 * based on ipt_limit.c by:
11 * Jérôme de Vivie <devivie@info.enserb.u-bordeaux.fr>
12 * Hervé Eychenne <eychenne@info.enserb.u-bordeaux.fr>
13 * Rusty Russell <rusty@rustcorp.com.au>
14 *
15 * The general idea is to create a hash table for every dstip and have a
16 * seperate limit counter per tuple. This way you can do something like 'limit
17 * the number of syn packets for each of my internal addresses.
18 *
19 * Ideally this would just be implemented as a general 'hash' match, which would
20 * allow us to attach any iptables target to it's hash buckets. But this is
21 * not possible in the current iptables architecture. As always, pkttables for
22 * 2.7.x will help ;)
23 */
24 #include <linux/module.h>
25 #include <linux/skbuff.h>
26 #include <linux/spinlock.h>
27 #include <linux/random.h>
28 #include <linux/jhash.h>
29 #include <linux/slab.h>
30 #include <linux/vmalloc.h>
31 #include <linux/proc_fs.h>
32 #include <linux/seq_file.h>
33 #include <linux/list.h>
34
35 #include <linux/netfilter_ipv4/ip_tables.h>
36 #include <linux/netfilter_ipv4/ipt_hashlimit.h>
37
38 /* FIXME: this is just for IP_NF_ASSERRT */
39 #include <linux/netfilter_ipv4/ip_conntrack.h>
40 #include <linux/mutex.h>
41
42 MODULE_LICENSE("GPL");
43 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
44 MODULE_DESCRIPTION("iptables match for limiting per hash-bucket");
45
46 /* need to declare this at the top */
47 static struct proc_dir_entry *hashlimit_procdir;
48 static struct file_operations dl_file_ops;
49
50 /* hash table crap */
51
52 struct dsthash_dst {
53 u_int32_t src_ip;
54 u_int32_t dst_ip;
55 /* ports have to be consecutive !!! */
56 u_int16_t src_port;
57 u_int16_t dst_port;
58 };
59
60 struct dsthash_ent {
61 /* static / read-only parts in the beginning */
62 struct hlist_node node;
63 struct dsthash_dst dst;
64
65 /* modified structure members in the end */
66 unsigned long expires; /* precalculated expiry time */
67 struct {
68 unsigned long prev; /* last modification */
69 u_int32_t credit;
70 u_int32_t credit_cap, cost;
71 } rateinfo;
72 };
73
74 struct ipt_hashlimit_htable {
75 struct hlist_node node; /* global list of all htables */
76 atomic_t use;
77
78 struct hashlimit_cfg cfg; /* config */
79
80 /* used internally */
81 spinlock_t lock; /* lock for list_head */
82 u_int32_t rnd; /* random seed for hash */
83 int rnd_initialized;
84 struct timer_list timer; /* timer for gc */
85 atomic_t count; /* number entries in table */
86
87 /* seq_file stuff */
88 struct proc_dir_entry *pde;
89
90 struct hlist_head hash[0]; /* hashtable itself */
91 };
92
93 static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */
94 static DEFINE_MUTEX(hlimit_mutex); /* additional checkentry protection */
95 static HLIST_HEAD(hashlimit_htables);
96 static kmem_cache_t *hashlimit_cachep __read_mostly;
97
98 static inline int dst_cmp(const struct dsthash_ent *ent, struct dsthash_dst *b)
99 {
100 return (ent->dst.dst_ip == b->dst_ip
101 && ent->dst.dst_port == b->dst_port
102 && ent->dst.src_port == b->src_port
103 && ent->dst.src_ip == b->src_ip);
104 }
105
106 static inline u_int32_t
107 hash_dst(const struct ipt_hashlimit_htable *ht, const struct dsthash_dst *dst)
108 {
109 return (jhash_3words(dst->dst_ip, (dst->dst_port<<16 | dst->src_port),
110 dst->src_ip, ht->rnd) % ht->cfg.size);
111 }
112
113 static inline struct dsthash_ent *
114 __dsthash_find(const struct ipt_hashlimit_htable *ht, struct dsthash_dst *dst)
115 {
116 struct dsthash_ent *ent;
117 struct hlist_node *pos;
118 u_int32_t hash = hash_dst(ht, dst);
119
120 if (!hlist_empty(&ht->hash[hash]))
121 hlist_for_each_entry(ent, pos, &ht->hash[hash], node) {
122 if (dst_cmp(ent, dst)) {
123 return ent;
124 }
125 }
126
127 return NULL;
128 }
129
130 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
131 static struct dsthash_ent *
132 __dsthash_alloc_init(struct ipt_hashlimit_htable *ht, struct dsthash_dst *dst)
133 {
134 struct dsthash_ent *ent;
135
136 /* initialize hash with random val at the time we allocate
137 * the first hashtable entry */
138 if (!ht->rnd_initialized) {
139 get_random_bytes(&ht->rnd, 4);
140 ht->rnd_initialized = 1;
141 }
142
143 if (ht->cfg.max &&
144 atomic_read(&ht->count) >= ht->cfg.max) {
145 /* FIXME: do something. question is what.. */
146 if (net_ratelimit())
147 printk(KERN_WARNING
148 "ipt_hashlimit: max count of %u reached\n",
149 ht->cfg.max);
150 return NULL;
151 }
152
153 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
154 if (!ent) {
155 if (net_ratelimit())
156 printk(KERN_ERR
157 "ipt_hashlimit: can't allocate dsthash_ent\n");
158 return NULL;
159 }
160
161 atomic_inc(&ht->count);
162
163 ent->dst.dst_ip = dst->dst_ip;
164 ent->dst.dst_port = dst->dst_port;
165 ent->dst.src_ip = dst->src_ip;
166 ent->dst.src_port = dst->src_port;
167
168 hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
169
170 return ent;
171 }
172
173 static inline void
174 __dsthash_free(struct ipt_hashlimit_htable *ht, struct dsthash_ent *ent)
175 {
176 hlist_del(&ent->node);
177 kmem_cache_free(hashlimit_cachep, ent);
178 atomic_dec(&ht->count);
179 }
180 static void htable_gc(unsigned long htlong);
181
182 static int htable_create(struct ipt_hashlimit_info *minfo)
183 {
184 int i;
185 unsigned int size;
186 struct ipt_hashlimit_htable *hinfo;
187
188 if (minfo->cfg.size)
189 size = minfo->cfg.size;
190 else {
191 size = (((num_physpages << PAGE_SHIFT) / 16384)
192 / sizeof(struct list_head));
193 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
194 size = 8192;
195 if (size < 16)
196 size = 16;
197 }
198 /* FIXME: don't use vmalloc() here or anywhere else -HW */
199 hinfo = vmalloc(sizeof(struct ipt_hashlimit_htable)
200 + (sizeof(struct list_head) * size));
201 if (!hinfo) {
202 printk(KERN_ERR "ipt_hashlimit: Unable to create hashtable\n");
203 return -1;
204 }
205 minfo->hinfo = hinfo;
206
207 /* copy match config into hashtable config */
208 memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
209 hinfo->cfg.size = size;
210 if (!hinfo->cfg.max)
211 hinfo->cfg.max = 8 * hinfo->cfg.size;
212 else if (hinfo->cfg.max < hinfo->cfg.size)
213 hinfo->cfg.max = hinfo->cfg.size;
214
215 for (i = 0; i < hinfo->cfg.size; i++)
216 INIT_HLIST_HEAD(&hinfo->hash[i]);
217
218 atomic_set(&hinfo->count, 0);
219 atomic_set(&hinfo->use, 1);
220 hinfo->rnd_initialized = 0;
221 spin_lock_init(&hinfo->lock);
222 hinfo->pde = create_proc_entry(minfo->name, 0, hashlimit_procdir);
223 if (!hinfo->pde) {
224 vfree(hinfo);
225 return -1;
226 }
227 hinfo->pde->proc_fops = &dl_file_ops;
228 hinfo->pde->data = hinfo;
229
230 init_timer(&hinfo->timer);
231 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
232 hinfo->timer.data = (unsigned long )hinfo;
233 hinfo->timer.function = htable_gc;
234 add_timer(&hinfo->timer);
235
236 spin_lock_bh(&hashlimit_lock);
237 hlist_add_head(&hinfo->node, &hashlimit_htables);
238 spin_unlock_bh(&hashlimit_lock);
239
240 return 0;
241 }
242
243 static int select_all(struct ipt_hashlimit_htable *ht, struct dsthash_ent *he)
244 {
245 return 1;
246 }
247
248 static int select_gc(struct ipt_hashlimit_htable *ht, struct dsthash_ent *he)
249 {
250 return (jiffies >= he->expires);
251 }
252
253 static void htable_selective_cleanup(struct ipt_hashlimit_htable *ht,
254 int (*select)(struct ipt_hashlimit_htable *ht,
255 struct dsthash_ent *he))
256 {
257 int i;
258
259 IP_NF_ASSERT(ht->cfg.size && ht->cfg.max);
260
261 /* lock hash table and iterate over it */
262 spin_lock_bh(&ht->lock);
263 for (i = 0; i < ht->cfg.size; i++) {
264 struct dsthash_ent *dh;
265 struct hlist_node *pos, *n;
266 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
267 if ((*select)(ht, dh))
268 __dsthash_free(ht, dh);
269 }
270 }
271 spin_unlock_bh(&ht->lock);
272 }
273
274 /* hash table garbage collector, run by timer */
275 static void htable_gc(unsigned long htlong)
276 {
277 struct ipt_hashlimit_htable *ht = (struct ipt_hashlimit_htable *)htlong;
278
279 htable_selective_cleanup(ht, select_gc);
280
281 /* re-add the timer accordingly */
282 ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
283 add_timer(&ht->timer);
284 }
285
286 static void htable_destroy(struct ipt_hashlimit_htable *hinfo)
287 {
288 /* remove timer, if it is pending */
289 if (timer_pending(&hinfo->timer))
290 del_timer(&hinfo->timer);
291
292 /* remove proc entry */
293 remove_proc_entry(hinfo->pde->name, hashlimit_procdir);
294
295 htable_selective_cleanup(hinfo, select_all);
296 vfree(hinfo);
297 }
298
299 static struct ipt_hashlimit_htable *htable_find_get(char *name)
300 {
301 struct ipt_hashlimit_htable *hinfo;
302 struct hlist_node *pos;
303
304 spin_lock_bh(&hashlimit_lock);
305 hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
306 if (!strcmp(name, hinfo->pde->name)) {
307 atomic_inc(&hinfo->use);
308 spin_unlock_bh(&hashlimit_lock);
309 return hinfo;
310 }
311 }
312 spin_unlock_bh(&hashlimit_lock);
313
314 return NULL;
315 }
316
317 static void htable_put(struct ipt_hashlimit_htable *hinfo)
318 {
319 if (atomic_dec_and_test(&hinfo->use)) {
320 spin_lock_bh(&hashlimit_lock);
321 hlist_del(&hinfo->node);
322 spin_unlock_bh(&hashlimit_lock);
323 htable_destroy(hinfo);
324 }
325 }
326
327
328 /* The algorithm used is the Simple Token Bucket Filter (TBF)
329 * see net/sched/sch_tbf.c in the linux source tree
330 */
331
332 /* Rusty: This is my (non-mathematically-inclined) understanding of
333 this algorithm. The `average rate' in jiffies becomes your initial
334 amount of credit `credit' and the most credit you can ever have
335 `credit_cap'. The `peak rate' becomes the cost of passing the
336 test, `cost'.
337
338 `prev' tracks the last packet hit: you gain one credit per jiffy.
339 If you get credit balance more than this, the extra credit is
340 discarded. Every time the match passes, you lose `cost' credits;
341 if you don't have that many, the test fails.
342
343 See Alexey's formal explanation in net/sched/sch_tbf.c.
344
345 To get the maximum range, we multiply by this factor (ie. you get N
346 credits per jiffy). We want to allow a rate as low as 1 per day
347 (slowest userspace tool allows), which means
348 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
349 */
350 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
351
352 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
353 * us the power of 2 below the theoretical max, so GCC simply does a
354 * shift. */
355 #define _POW2_BELOW2(x) ((x)|((x)>>1))
356 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
357 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
358 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
359 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
360 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
361
362 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
363
364 /* Precision saver. */
365 static inline u_int32_t
366 user2credits(u_int32_t user)
367 {
368 /* If multiplying would overflow... */
369 if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
370 /* Divide first. */
371 return (user / IPT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
372
373 return (user * HZ * CREDITS_PER_JIFFY) / IPT_HASHLIMIT_SCALE;
374 }
375
376 static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
377 {
378 dh->rateinfo.credit += (now - xchg(&dh->rateinfo.prev, now))
379 * CREDITS_PER_JIFFY;
380 if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
381 dh->rateinfo.credit = dh->rateinfo.credit_cap;
382 }
383
384 static int
385 hashlimit_match(const struct sk_buff *skb,
386 const struct net_device *in,
387 const struct net_device *out,
388 const struct xt_match *match,
389 const void *matchinfo,
390 int offset,
391 unsigned int protoff,
392 int *hotdrop)
393 {
394 struct ipt_hashlimit_info *r =
395 ((struct ipt_hashlimit_info *)matchinfo)->u.master;
396 struct ipt_hashlimit_htable *hinfo = r->hinfo;
397 unsigned long now = jiffies;
398 struct dsthash_ent *dh;
399 struct dsthash_dst dst;
400
401 /* build 'dst' according to hinfo->cfg and current packet */
402 memset(&dst, 0, sizeof(dst));
403 if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_DIP)
404 dst.dst_ip = skb->nh.iph->daddr;
405 if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_SIP)
406 dst.src_ip = skb->nh.iph->saddr;
407 if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_DPT
408 ||hinfo->cfg.mode & IPT_HASHLIMIT_HASH_SPT) {
409 u_int16_t _ports[2], *ports;
410
411 switch (skb->nh.iph->protocol) {
412 case IPPROTO_TCP:
413 case IPPROTO_UDP:
414 case IPPROTO_SCTP:
415 case IPPROTO_DCCP:
416 ports = skb_header_pointer(skb, skb->nh.iph->ihl*4,
417 sizeof(_ports), &_ports);
418 break;
419 default:
420 _ports[0] = _ports[1] = 0;
421 ports = _ports;
422 break;
423 }
424 if (!ports) {
425 /* We've been asked to examine this packet, and we
426 can't. Hence, no choice but to drop. */
427 *hotdrop = 1;
428 return 0;
429 }
430 if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_SPT)
431 dst.src_port = ports[0];
432 if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_DPT)
433 dst.dst_port = ports[1];
434 }
435
436 spin_lock_bh(&hinfo->lock);
437 dh = __dsthash_find(hinfo, &dst);
438 if (!dh) {
439 dh = __dsthash_alloc_init(hinfo, &dst);
440
441 if (!dh) {
442 /* enomem... don't match == DROP */
443 if (net_ratelimit())
444 printk(KERN_ERR "%s: ENOMEM\n", __FUNCTION__);
445 spin_unlock_bh(&hinfo->lock);
446 return 0;
447 }
448
449 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
450
451 dh->rateinfo.prev = jiffies;
452 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
453 hinfo->cfg.burst);
454 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
455 hinfo->cfg.burst);
456 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
457
458 spin_unlock_bh(&hinfo->lock);
459 return 1;
460 }
461
462 /* update expiration timeout */
463 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
464
465 rateinfo_recalc(dh, now);
466 if (dh->rateinfo.credit >= dh->rateinfo.cost) {
467 /* We're underlimit. */
468 dh->rateinfo.credit -= dh->rateinfo.cost;
469 spin_unlock_bh(&hinfo->lock);
470 return 1;
471 }
472
473 spin_unlock_bh(&hinfo->lock);
474
475 /* default case: we're overlimit, thus don't match */
476 return 0;
477 }
478
479 static int
480 hashlimit_checkentry(const char *tablename,
481 const void *inf,
482 const struct xt_match *match,
483 void *matchinfo,
484 unsigned int matchsize,
485 unsigned int hook_mask)
486 {
487 struct ipt_hashlimit_info *r = matchinfo;
488
489 /* Check for overflow. */
490 if (r->cfg.burst == 0
491 || user2credits(r->cfg.avg * r->cfg.burst) <
492 user2credits(r->cfg.avg)) {
493 printk(KERN_ERR "ipt_hashlimit: Overflow, try lower: %u/%u\n",
494 r->cfg.avg, r->cfg.burst);
495 return 0;
496 }
497
498 if (r->cfg.mode == 0
499 || r->cfg.mode > (IPT_HASHLIMIT_HASH_DPT
500 |IPT_HASHLIMIT_HASH_DIP
501 |IPT_HASHLIMIT_HASH_SIP
502 |IPT_HASHLIMIT_HASH_SPT))
503 return 0;
504
505 if (!r->cfg.gc_interval)
506 return 0;
507
508 if (!r->cfg.expire)
509 return 0;
510
511 if (r->name[sizeof(r->name) - 1] != '\0')
512 return 0;
513
514 /* This is the best we've got: We cannot release and re-grab lock,
515 * since checkentry() is called before ip_tables.c grabs ipt_mutex.
516 * We also cannot grab the hashtable spinlock, since htable_create will
517 * call vmalloc, and that can sleep. And we cannot just re-search
518 * the list of htable's in htable_create(), since then we would
519 * create duplicate proc files. -HW */
520 mutex_lock(&hlimit_mutex);
521 r->hinfo = htable_find_get(r->name);
522 if (!r->hinfo && (htable_create(r) != 0)) {
523 mutex_unlock(&hlimit_mutex);
524 return 0;
525 }
526 mutex_unlock(&hlimit_mutex);
527
528 /* Ugly hack: For SMP, we only want to use one set */
529 r->u.master = r;
530
531 return 1;
532 }
533
534 static void
535 hashlimit_destroy(const struct xt_match *match, void *matchinfo,
536 unsigned int matchsize)
537 {
538 struct ipt_hashlimit_info *r = matchinfo;
539
540 htable_put(r->hinfo);
541 }
542
543 static struct ipt_match ipt_hashlimit = {
544 .name = "hashlimit",
545 .match = hashlimit_match,
546 .matchsize = sizeof(struct ipt_hashlimit_info),
547 .checkentry = hashlimit_checkentry,
548 .destroy = hashlimit_destroy,
549 .me = THIS_MODULE
550 };
551
552 /* PROC stuff */
553
554 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
555 {
556 struct proc_dir_entry *pde = s->private;
557 struct ipt_hashlimit_htable *htable = pde->data;
558 unsigned int *bucket;
559
560 spin_lock_bh(&htable->lock);
561 if (*pos >= htable->cfg.size)
562 return NULL;
563
564 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
565 if (!bucket)
566 return ERR_PTR(-ENOMEM);
567
568 *bucket = *pos;
569 return bucket;
570 }
571
572 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
573 {
574 struct proc_dir_entry *pde = s->private;
575 struct ipt_hashlimit_htable *htable = pde->data;
576 unsigned int *bucket = (unsigned int *)v;
577
578 *pos = ++(*bucket);
579 if (*pos >= htable->cfg.size) {
580 kfree(v);
581 return NULL;
582 }
583 return bucket;
584 }
585
586 static void dl_seq_stop(struct seq_file *s, void *v)
587 {
588 struct proc_dir_entry *pde = s->private;
589 struct ipt_hashlimit_htable *htable = pde->data;
590 unsigned int *bucket = (unsigned int *)v;
591
592 kfree(bucket);
593
594 spin_unlock_bh(&htable->lock);
595 }
596
597 static inline int dl_seq_real_show(struct dsthash_ent *ent, struct seq_file *s)
598 {
599 /* recalculate to show accurate numbers */
600 rateinfo_recalc(ent, jiffies);
601
602 return seq_printf(s, "%ld %u.%u.%u.%u:%u->%u.%u.%u.%u:%u %u %u %u\n",
603 (long)(ent->expires - jiffies)/HZ,
604 NIPQUAD(ent->dst.src_ip), ntohs(ent->dst.src_port),
605 NIPQUAD(ent->dst.dst_ip), ntohs(ent->dst.dst_port),
606 ent->rateinfo.credit, ent->rateinfo.credit_cap,
607 ent->rateinfo.cost);
608 }
609
610 static int dl_seq_show(struct seq_file *s, void *v)
611 {
612 struct proc_dir_entry *pde = s->private;
613 struct ipt_hashlimit_htable *htable = pde->data;
614 unsigned int *bucket = (unsigned int *)v;
615 struct dsthash_ent *ent;
616 struct hlist_node *pos;
617
618 if (!hlist_empty(&htable->hash[*bucket]))
619 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node) {
620 if (dl_seq_real_show(ent, s)) {
621 /* buffer was filled and unable to print that tuple */
622 return 1;
623 }
624 }
625
626 return 0;
627 }
628
629 static struct seq_operations dl_seq_ops = {
630 .start = dl_seq_start,
631 .next = dl_seq_next,
632 .stop = dl_seq_stop,
633 .show = dl_seq_show
634 };
635
636 static int dl_proc_open(struct inode *inode, struct file *file)
637 {
638 int ret = seq_open(file, &dl_seq_ops);
639
640 if (!ret) {
641 struct seq_file *sf = file->private_data;
642 sf->private = PDE(inode);
643 }
644 return ret;
645 }
646
647 static struct file_operations dl_file_ops = {
648 .owner = THIS_MODULE,
649 .open = dl_proc_open,
650 .read = seq_read,
651 .llseek = seq_lseek,
652 .release = seq_release
653 };
654
655 static int init_or_fini(int fini)
656 {
657 int ret = 0;
658
659 if (fini)
660 goto cleanup;
661
662 if (ipt_register_match(&ipt_hashlimit)) {
663 ret = -EINVAL;
664 goto cleanup_nothing;
665 }
666
667 hashlimit_cachep = kmem_cache_create("ipt_hashlimit",
668 sizeof(struct dsthash_ent), 0,
669 0, NULL, NULL);
670 if (!hashlimit_cachep) {
671 printk(KERN_ERR "Unable to create ipt_hashlimit slab cache\n");
672 ret = -ENOMEM;
673 goto cleanup_unreg_match;
674 }
675
676 hashlimit_procdir = proc_mkdir("ipt_hashlimit", proc_net);
677 if (!hashlimit_procdir) {
678 printk(KERN_ERR "Unable to create proc dir entry\n");
679 ret = -ENOMEM;
680 goto cleanup_free_slab;
681 }
682
683 return ret;
684
685 cleanup:
686 remove_proc_entry("ipt_hashlimit", proc_net);
687 cleanup_free_slab:
688 kmem_cache_destroy(hashlimit_cachep);
689 cleanup_unreg_match:
690 ipt_unregister_match(&ipt_hashlimit);
691 cleanup_nothing:
692 return ret;
693
694 }
695
696 static int __init ipt_hashlimit_init(void)
697 {
698 return init_or_fini(0);
699 }
700
701 static void __exit ipt_hashlimit_fini(void)
702 {
703 init_or_fini(1);
704 }
705
706 module_init(ipt_hashlimit_init);
707 module_exit(ipt_hashlimit_fini);
kmemtrace - Kernel memory tracer