[NETFILTER]: xtables: fixes warning on compilation of hashlimit
[linux-2.6.git] / net / netfilter / xt_hashlimit.c
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 #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/in.h>
21 #include <linux/ip.h>
22 #include <linux/ipv6.h>
23
24 #include <linux/netfilter/x_tables.h>
25 #include <linux/netfilter_ipv4/ip_tables.h>
26 #include <linux/netfilter_ipv6/ip6_tables.h>
27 #include <linux/netfilter/xt_hashlimit.h>
28 #include <linux/mutex.h>
29
30 MODULE_LICENSE("GPL");
31 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
32 MODULE_DESCRIPTION("iptables match for limiting per hash-bucket");
33 MODULE_ALIAS("ipt_hashlimit");
34 MODULE_ALIAS("ip6t_hashlimit");
35
36 /* need to declare this at the top */
37 static struct proc_dir_entry *hashlimit_procdir4;
38 static struct proc_dir_entry *hashlimit_procdir6;
39 static struct file_operations dl_file_ops;
40
41 /* hash table crap */
42 struct dsthash_dst {
43         union {
44                 struct {
45                         __be32 src;
46                         __be32 dst;
47                 } ip;
48                 struct {
49                         __be32 src[4];
50                         __be32 dst[4];
51                 } ip6;
52         } addr;
53         __be16 src_port;
54         __be16 dst_port;
55 };
56
57 struct dsthash_ent {
58         /* static / read-only parts in the beginning */
59         struct hlist_node node;
60         struct dsthash_dst dst;
61
62         /* modified structure members in the end */
63         unsigned long expires;          /* precalculated expiry time */
64         struct {
65                 unsigned long prev;     /* last modification */
66                 u_int32_t credit;
67                 u_int32_t credit_cap, cost;
68         } rateinfo;
69 };
70
71 struct xt_hashlimit_htable {
72         struct hlist_node node;         /* global list of all htables */
73         atomic_t use;
74         int family;
75
76         struct hashlimit_cfg cfg;       /* config */
77
78         /* used internally */
79         spinlock_t lock;                /* lock for list_head */
80         u_int32_t rnd;                  /* random seed for hash */
81         int rnd_initialized;
82         unsigned int count;             /* number entries in table */
83         struct timer_list timer;        /* timer for gc */
84
85         /* seq_file stuff */
86         struct proc_dir_entry *pde;
87
88         struct hlist_head hash[0];      /* hashtable itself */
89 };
90
91 static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */
92 static DEFINE_MUTEX(hlimit_mutex);      /* additional checkentry protection */
93 static HLIST_HEAD(hashlimit_htables);
94 static kmem_cache_t *hashlimit_cachep __read_mostly;
95
96 static inline int dst_cmp(const struct dsthash_ent *ent, struct dsthash_dst *b)
97 {
98         return !memcmp(&ent->dst, b, sizeof(ent->dst));
99 }
100
101 static u_int32_t
102 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
103 {
104         return jhash(dst, sizeof(*dst), ht->rnd) % ht->cfg.size;
105 }
106
107 static struct dsthash_ent *
108 dsthash_find(const struct xt_hashlimit_htable *ht, struct dsthash_dst *dst)
109 {
110         struct dsthash_ent *ent;
111         struct hlist_node *pos;
112         u_int32_t hash = hash_dst(ht, dst);
113
114         if (!hlist_empty(&ht->hash[hash])) {
115                 hlist_for_each_entry(ent, pos, &ht->hash[hash], node)
116                         if (dst_cmp(ent, dst))
117                                 return ent;
118         }
119         return NULL;
120 }
121
122 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
123 static struct dsthash_ent *
124 dsthash_alloc_init(struct xt_hashlimit_htable *ht, struct dsthash_dst *dst)
125 {
126         struct dsthash_ent *ent;
127
128         /* initialize hash with random val at the time we allocate
129          * the first hashtable entry */
130         if (!ht->rnd_initialized) {
131                 get_random_bytes(&ht->rnd, 4);
132                 ht->rnd_initialized = 1;
133         }
134
135         if (ht->cfg.max && ht->count >= ht->cfg.max) {
136                 /* FIXME: do something. question is what.. */
137                 if (net_ratelimit())
138                         printk(KERN_WARNING
139                                 "xt_hashlimit: max count of %u reached\n",
140                                 ht->cfg.max);
141                 return NULL;
142         }
143
144         ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
145         if (!ent) {
146                 if (net_ratelimit())
147                         printk(KERN_ERR
148                                 "xt_hashlimit: can't allocate dsthash_ent\n");
149                 return NULL;
150         }
151         memcpy(&ent->dst, dst, sizeof(ent->dst));
152
153         hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
154         ht->count++;
155         return ent;
156 }
157
158 static inline void
159 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
160 {
161         hlist_del(&ent->node);
162         kmem_cache_free(hashlimit_cachep, ent);
163         ht->count--;
164 }
165 static void htable_gc(unsigned long htlong);
166
167 static int htable_create(struct xt_hashlimit_info *minfo, int family)
168 {
169         struct xt_hashlimit_htable *hinfo;
170         unsigned int size;
171         unsigned int i;
172
173         if (minfo->cfg.size)
174                 size = minfo->cfg.size;
175         else {
176                 size = ((num_physpages << PAGE_SHIFT) / 16384) /
177                        sizeof(struct list_head);
178                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
179                         size = 8192;
180                 if (size < 16)
181                         size = 16;
182         }
183         /* FIXME: don't use vmalloc() here or anywhere else -HW */
184         hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
185                         sizeof(struct list_head) * size);
186         if (!hinfo) {
187                 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
188                 return -1;
189         }
190         minfo->hinfo = hinfo;
191
192         /* copy match config into hashtable config */
193         memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
194         hinfo->cfg.size = size;
195         if (!hinfo->cfg.max)
196                 hinfo->cfg.max = 8 * hinfo->cfg.size;
197         else if (hinfo->cfg.max < hinfo->cfg.size)
198                 hinfo->cfg.max = hinfo->cfg.size;
199
200         for (i = 0; i < hinfo->cfg.size; i++)
201                 INIT_HLIST_HEAD(&hinfo->hash[i]);
202
203         atomic_set(&hinfo->use, 1);
204         hinfo->count = 0;
205         hinfo->family = family;
206         hinfo->rnd_initialized = 0;
207         spin_lock_init(&hinfo->lock);
208         hinfo->pde = create_proc_entry(minfo->name, 0,
209                                        family == AF_INET ? hashlimit_procdir4 :
210                                                            hashlimit_procdir6);
211         if (!hinfo->pde) {
212                 vfree(hinfo);
213                 return -1;
214         }
215         hinfo->pde->proc_fops = &dl_file_ops;
216         hinfo->pde->data = hinfo;
217
218         init_timer(&hinfo->timer);
219         hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
220         hinfo->timer.data = (unsigned long )hinfo;
221         hinfo->timer.function = htable_gc;
222         add_timer(&hinfo->timer);
223
224         spin_lock_bh(&hashlimit_lock);
225         hlist_add_head(&hinfo->node, &hashlimit_htables);
226         spin_unlock_bh(&hashlimit_lock);
227
228         return 0;
229 }
230
231 static int select_all(struct xt_hashlimit_htable *ht, struct dsthash_ent *he)
232 {
233         return 1;
234 }
235
236 static int select_gc(struct xt_hashlimit_htable *ht, struct dsthash_ent *he)
237 {
238         return (jiffies >= he->expires);
239 }
240
241 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
242                                 int (*select)(struct xt_hashlimit_htable *ht,
243                                               struct dsthash_ent *he))
244 {
245         unsigned int i;
246
247         /* lock hash table and iterate over it */
248         spin_lock_bh(&ht->lock);
249         for (i = 0; i < ht->cfg.size; i++) {
250                 struct dsthash_ent *dh;
251                 struct hlist_node *pos, *n;
252                 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
253                         if ((*select)(ht, dh))
254                                 dsthash_free(ht, dh);
255                 }
256         }
257         spin_unlock_bh(&ht->lock);
258 }
259
260 /* hash table garbage collector, run by timer */
261 static void htable_gc(unsigned long htlong)
262 {
263         struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
264
265         htable_selective_cleanup(ht, select_gc);
266
267         /* re-add the timer accordingly */
268         ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
269         add_timer(&ht->timer);
270 }
271
272 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
273 {
274         /* remove timer, if it is pending */
275         if (timer_pending(&hinfo->timer))
276                 del_timer(&hinfo->timer);
277
278         /* remove proc entry */
279         remove_proc_entry(hinfo->pde->name,
280                           hinfo->family == AF_INET ? hashlimit_procdir4 :
281                                                      hashlimit_procdir6);
282         htable_selective_cleanup(hinfo, select_all);
283         vfree(hinfo);
284 }
285
286 static struct xt_hashlimit_htable *htable_find_get(char *name, int family)
287 {
288         struct xt_hashlimit_htable *hinfo;
289         struct hlist_node *pos;
290
291         spin_lock_bh(&hashlimit_lock);
292         hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
293                 if (!strcmp(name, hinfo->pde->name) &&
294                     hinfo->family == family) {
295                         atomic_inc(&hinfo->use);
296                         spin_unlock_bh(&hashlimit_lock);
297                         return hinfo;
298                 }
299         }
300         spin_unlock_bh(&hashlimit_lock);
301         return NULL;
302 }
303
304 static void htable_put(struct xt_hashlimit_htable *hinfo)
305 {
306         if (atomic_dec_and_test(&hinfo->use)) {
307                 spin_lock_bh(&hashlimit_lock);
308                 hlist_del(&hinfo->node);
309                 spin_unlock_bh(&hashlimit_lock);
310                 htable_destroy(hinfo);
311         }
312 }
313
314 /* The algorithm used is the Simple Token Bucket Filter (TBF)
315  * see net/sched/sch_tbf.c in the linux source tree
316  */
317
318 /* Rusty: This is my (non-mathematically-inclined) understanding of
319    this algorithm.  The `average rate' in jiffies becomes your initial
320    amount of credit `credit' and the most credit you can ever have
321    `credit_cap'.  The `peak rate' becomes the cost of passing the
322    test, `cost'.
323
324    `prev' tracks the last packet hit: you gain one credit per jiffy.
325    If you get credit balance more than this, the extra credit is
326    discarded.  Every time the match passes, you lose `cost' credits;
327    if you don't have that many, the test fails.
328
329    See Alexey's formal explanation in net/sched/sch_tbf.c.
330
331    To get the maximum range, we multiply by this factor (ie. you get N
332    credits per jiffy).  We want to allow a rate as low as 1 per day
333    (slowest userspace tool allows), which means
334    CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
335 */
336 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
337
338 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
339  * us the power of 2 below the theoretical max, so GCC simply does a
340  * shift. */
341 #define _POW2_BELOW2(x) ((x)|((x)>>1))
342 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
343 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
344 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
345 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
346 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
347
348 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
349
350 /* Precision saver. */
351 static inline u_int32_t
352 user2credits(u_int32_t user)
353 {
354         /* If multiplying would overflow... */
355         if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
356                 /* Divide first. */
357                 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
358
359         return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
360 }
361
362 static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
363 {
364         dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
365         if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
366                 dh->rateinfo.credit = dh->rateinfo.credit_cap;
367         dh->rateinfo.prev = now;
368 }
369
370 static int
371 hashlimit_init_dst(struct xt_hashlimit_htable *hinfo, struct dsthash_dst *dst,
372                    const struct sk_buff *skb, unsigned int protoff)
373 {
374         __be16 _ports[2], *ports;
375         int nexthdr;
376
377         memset(dst, 0, sizeof(*dst));
378
379         switch (hinfo->family) {
380         case AF_INET:
381                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
382                         dst->addr.ip.dst = skb->nh.iph->daddr;
383                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
384                         dst->addr.ip.src = skb->nh.iph->saddr;
385
386                 if (!(hinfo->cfg.mode &
387                       (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
388                         return 0;
389                 nexthdr = skb->nh.iph->protocol;
390                 break;
391 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
392         case AF_INET6:
393                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
394                         memcpy(&dst->addr.ip6.dst, &skb->nh.ipv6h->daddr,
395                                sizeof(dst->addr.ip6.dst));
396                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
397                         memcpy(&dst->addr.ip6.src, &skb->nh.ipv6h->saddr,
398                                sizeof(dst->addr.ip6.src));
399
400                 if (!(hinfo->cfg.mode &
401                       (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
402                         return 0;
403                 nexthdr = ipv6_find_hdr(skb, &protoff, -1, NULL);
404                 if (nexthdr < 0)
405                         return -1;
406                 break;
407 #endif
408         default:
409                 BUG();
410                 return 0;
411         }
412
413         switch (nexthdr) {
414         case IPPROTO_TCP:
415         case IPPROTO_UDP:
416         case IPPROTO_SCTP:
417         case IPPROTO_DCCP:
418                 ports = skb_header_pointer(skb, protoff, sizeof(_ports),
419                                            &_ports);
420                 break;
421         default:
422                 _ports[0] = _ports[1] = 0;
423                 ports = _ports;
424                 break;
425         }
426         if (!ports)
427                 return -1;
428         if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
429                 dst->src_port = ports[0];
430         if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
431                 dst->dst_port = ports[1];
432         return 0;
433 }
434
435 static int
436 hashlimit_match(const struct sk_buff *skb,
437                 const struct net_device *in,
438                 const struct net_device *out,
439                 const struct xt_match *match,
440                 const void *matchinfo,
441                 int offset,
442                 unsigned int protoff,
443                 int *hotdrop)
444 {
445         struct xt_hashlimit_info *r =
446                 ((struct xt_hashlimit_info *)matchinfo)->u.master;
447         struct xt_hashlimit_htable *hinfo = r->hinfo;
448         unsigned long now = jiffies;
449         struct dsthash_ent *dh;
450         struct dsthash_dst dst;
451
452         if (hashlimit_init_dst(hinfo, &dst, skb, protoff) < 0)
453                 goto hotdrop;
454
455         spin_lock_bh(&hinfo->lock);
456         dh = dsthash_find(hinfo, &dst);
457         if (!dh) {
458                 dh = dsthash_alloc_init(hinfo, &dst);
459                 if (!dh) {
460                         spin_unlock_bh(&hinfo->lock);
461                         goto hotdrop;
462                 }
463
464                 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
465                 dh->rateinfo.prev = jiffies;
466                 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
467                                                    hinfo->cfg.burst);
468                 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
469                                                        hinfo->cfg.burst);
470                 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
471         } else {
472                 /* update expiration timeout */
473                 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
474                 rateinfo_recalc(dh, now);
475         }
476
477         if (dh->rateinfo.credit >= dh->rateinfo.cost) {
478                 /* We're underlimit. */
479                 dh->rateinfo.credit -= dh->rateinfo.cost;
480                 spin_unlock_bh(&hinfo->lock);
481                 return 1;
482         }
483
484         spin_unlock_bh(&hinfo->lock);
485
486         /* default case: we're overlimit, thus don't match */
487         return 0;
488
489 hotdrop:
490         *hotdrop = 1;
491         return 0;
492 }
493
494 static int
495 hashlimit_checkentry(const char *tablename,
496                      const void *inf,
497                      const struct xt_match *match,
498                      void *matchinfo,
499                      unsigned int hook_mask)
500 {
501         struct xt_hashlimit_info *r = matchinfo;
502
503         /* Check for overflow. */
504         if (r->cfg.burst == 0 ||
505             user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
506                 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
507                        r->cfg.avg, r->cfg.burst);
508                 return 0;
509         }
510         if (r->cfg.mode == 0 ||
511             r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
512                            XT_HASHLIMIT_HASH_DIP |
513                            XT_HASHLIMIT_HASH_SIP |
514                            XT_HASHLIMIT_HASH_SPT))
515                 return 0;
516         if (!r->cfg.gc_interval)
517                 return 0;
518         if (!r->cfg.expire)
519                 return 0;
520         if (r->name[sizeof(r->name) - 1] != '\0')
521                 return 0;
522
523         /* This is the best we've got: We cannot release and re-grab lock,
524          * since checkentry() is called before x_tables.c grabs xt_mutex.
525          * We also cannot grab the hashtable spinlock, since htable_create will
526          * call vmalloc, and that can sleep.  And we cannot just re-search
527          * the list of htable's in htable_create(), since then we would
528          * create duplicate proc files. -HW */
529         mutex_lock(&hlimit_mutex);
530         r->hinfo = htable_find_get(r->name, match->family);
531         if (!r->hinfo && htable_create(r, match->family) != 0) {
532                 mutex_unlock(&hlimit_mutex);
533                 return 0;
534         }
535         mutex_unlock(&hlimit_mutex);
536
537         /* Ugly hack: For SMP, we only want to use one set */
538         r->u.master = r;
539         return 1;
540 }
541
542 static void
543 hashlimit_destroy(const struct xt_match *match, void *matchinfo)
544 {
545         struct xt_hashlimit_info *r = matchinfo;
546
547         htable_put(r->hinfo);
548 }
549
550 #ifdef CONFIG_COMPAT
551 struct compat_xt_hashlimit_info {
552         char name[IFNAMSIZ];
553         struct hashlimit_cfg cfg;
554         compat_uptr_t hinfo;
555         compat_uptr_t master;
556 };
557
558 static void compat_from_user(void *dst, void *src)
559 {
560         int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
561
562         memcpy(dst, src, off);
563         memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
564 }
565
566 static int compat_to_user(void __user *dst, void *src)
567 {
568         int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
569
570         return copy_to_user(dst, src, off) ? -EFAULT : 0;
571 }
572 #endif
573
574 static struct xt_match xt_hashlimit[] = {
575         {
576                 .name           = "hashlimit",
577                 .family         = AF_INET,
578                 .match          = hashlimit_match,
579                 .matchsize      = sizeof(struct xt_hashlimit_info),
580 #ifdef CONFIG_COMPAT
581                 .compatsize     = sizeof(struct compat_xt_hashlimit_info),
582                 .compat_from_user = compat_from_user,
583                 .compat_to_user = compat_to_user,
584 #endif
585                 .checkentry     = hashlimit_checkentry,
586                 .destroy        = hashlimit_destroy,
587                 .me             = THIS_MODULE
588         },
589         {
590                 .name           = "hashlimit",
591                 .family         = AF_INET6,
592                 .match          = hashlimit_match,
593                 .matchsize      = sizeof(struct xt_hashlimit_info),
594 #ifdef CONFIG_COMPAT
595                 .compatsize     = sizeof(struct compat_xt_hashlimit_info),
596                 .compat_from_user = compat_from_user,
597                 .compat_to_user = compat_to_user,
598 #endif
599                 .checkentry     = hashlimit_checkentry,
600                 .destroy        = hashlimit_destroy,
601                 .me             = THIS_MODULE
602         },
603 };
604
605 /* PROC stuff */
606 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
607 {
608         struct proc_dir_entry *pde = s->private;
609         struct xt_hashlimit_htable *htable = pde->data;
610         unsigned int *bucket;
611
612         spin_lock_bh(&htable->lock);
613         if (*pos >= htable->cfg.size)
614                 return NULL;
615
616         bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
617         if (!bucket)
618                 return ERR_PTR(-ENOMEM);
619
620         *bucket = *pos;
621         return bucket;
622 }
623
624 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
625 {
626         struct proc_dir_entry *pde = s->private;
627         struct xt_hashlimit_htable *htable = pde->data;
628         unsigned int *bucket = (unsigned int *)v;
629
630         *pos = ++(*bucket);
631         if (*pos >= htable->cfg.size) {
632                 kfree(v);
633                 return NULL;
634         }
635         return bucket;
636 }
637
638 static void dl_seq_stop(struct seq_file *s, void *v)
639 {
640         struct proc_dir_entry *pde = s->private;
641         struct xt_hashlimit_htable *htable = pde->data;
642         unsigned int *bucket = (unsigned int *)v;
643
644         kfree(bucket);
645         spin_unlock_bh(&htable->lock);
646 }
647
648 static int dl_seq_real_show(struct dsthash_ent *ent, int family,
649                                    struct seq_file *s)
650 {
651         /* recalculate to show accurate numbers */
652         rateinfo_recalc(ent, jiffies);
653
654         switch (family) {
655         case AF_INET:
656                 return seq_printf(s, "%ld %u.%u.%u.%u:%u->"
657                                      "%u.%u.%u.%u:%u %u %u %u\n",
658                                  (long)(ent->expires - jiffies)/HZ,
659                                  NIPQUAD(ent->dst.addr.ip.src),
660                                  ntohs(ent->dst.src_port),
661                                  NIPQUAD(ent->dst.addr.ip.dst),
662                                  ntohs(ent->dst.dst_port),
663                                  ent->rateinfo.credit, ent->rateinfo.credit_cap,
664                                  ent->rateinfo.cost);
665         case AF_INET6:
666                 return seq_printf(s, "%ld " NIP6_FMT ":%u->"
667                                      NIP6_FMT ":%u %u %u %u\n",
668                                  (long)(ent->expires - jiffies)/HZ,
669                                  NIP6(*(struct in6_addr *)&ent->dst.addr.ip6.src),
670                                  ntohs(ent->dst.src_port),
671                                  NIP6(*(struct in6_addr *)&ent->dst.addr.ip6.dst),
672                                  ntohs(ent->dst.dst_port),
673                                  ent->rateinfo.credit, ent->rateinfo.credit_cap,
674                                  ent->rateinfo.cost);
675         default:
676                 BUG();
677                 return 0;
678         }
679 }
680
681 static int dl_seq_show(struct seq_file *s, void *v)
682 {
683         struct proc_dir_entry *pde = s->private;
684         struct xt_hashlimit_htable *htable = pde->data;
685         unsigned int *bucket = (unsigned int *)v;
686         struct dsthash_ent *ent;
687         struct hlist_node *pos;
688
689         if (!hlist_empty(&htable->hash[*bucket])) {
690                 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
691                         if (dl_seq_real_show(ent, htable->family, s))
692                                 return 1;
693         }
694         return 0;
695 }
696
697 static struct seq_operations dl_seq_ops = {
698         .start = dl_seq_start,
699         .next  = dl_seq_next,
700         .stop  = dl_seq_stop,
701         .show  = dl_seq_show
702 };
703
704 static int dl_proc_open(struct inode *inode, struct file *file)
705 {
706         int ret = seq_open(file, &dl_seq_ops);
707
708         if (!ret) {
709                 struct seq_file *sf = file->private_data;
710                 sf->private = PDE(inode);
711         }
712         return ret;
713 }
714
715 static struct file_operations dl_file_ops = {
716         .owner   = THIS_MODULE,
717         .open    = dl_proc_open,
718         .read    = seq_read,
719         .llseek  = seq_lseek,
720         .release = seq_release
721 };
722
723 static int __init xt_hashlimit_init(void)
724 {
725         int err;
726
727         err = xt_register_matches(xt_hashlimit, ARRAY_SIZE(xt_hashlimit));
728         if (err < 0)
729                 goto err1;
730
731         err = -ENOMEM;
732         hashlimit_cachep = kmem_cache_create("xt_hashlimit",
733                                             sizeof(struct dsthash_ent), 0, 0,
734                                             NULL, NULL);
735         if (!hashlimit_cachep) {
736                 printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
737                 goto err2;
738         }
739         hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", proc_net);
740         if (!hashlimit_procdir4) {
741                 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
742                                 "entry\n");
743                 goto err3;
744         }
745         hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", proc_net);
746         if (!hashlimit_procdir6) {
747                 printk(KERN_ERR "xt_hashlimit: tnable to create proc dir "
748                                 "entry\n");
749                 goto err4;
750         }
751         return 0;
752 err4:
753         remove_proc_entry("ipt_hashlimit", proc_net);
754 err3:
755         kmem_cache_destroy(hashlimit_cachep);
756 err2:
757         xt_unregister_matches(xt_hashlimit, ARRAY_SIZE(xt_hashlimit));
758 err1:
759         return err;
760
761 }
762
763 static void __exit xt_hashlimit_fini(void)
764 {
765         remove_proc_entry("ipt_hashlimit", proc_net);
766         remove_proc_entry("ip6t_hashlimit", proc_net);
767         kmem_cache_destroy(hashlimit_cachep);
768         xt_unregister_matches(xt_hashlimit, ARRAY_SIZE(xt_hashlimit));
769 }
770
771 module_init(xt_hashlimit_init);
772 module_exit(xt_hashlimit_fini);