d6b3d01975b6e5664b969e1ce81bb2f11fa2adcb
[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/mm.h>
21 #include <linux/in.h>
22 #include <linux/ip.h>
23 #include <linux/ipv6.h>
24
25 #include <linux/netfilter/x_tables.h>
26 #include <linux/netfilter_ipv4/ip_tables.h>
27 #include <linux/netfilter_ipv6/ip6_tables.h>
28 #include <linux/netfilter/xt_hashlimit.h>
29 #include <linux/mutex.h>
30
31 MODULE_LICENSE("GPL");
32 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
33 MODULE_DESCRIPTION("iptables match for limiting per hash-bucket");
34 MODULE_ALIAS("ipt_hashlimit");
35 MODULE_ALIAS("ip6t_hashlimit");
36
37 /* need to declare this at the top */
38 static struct proc_dir_entry *hashlimit_procdir4;
39 static struct proc_dir_entry *hashlimit_procdir6;
40 static const struct file_operations dl_file_ops;
41
42 /* hash table crap */
43 struct dsthash_dst {
44         union {
45                 struct {
46                         __be32 src;
47                         __be32 dst;
48                 } ip;
49                 struct {
50                         __be32 src[4];
51                         __be32 dst[4];
52                 } ip6;
53         } addr;
54         __be16 src_port;
55         __be16 dst_port;
56 };
57
58 struct dsthash_ent {
59         /* static / read-only parts in the beginning */
60         struct hlist_node node;
61         struct dsthash_dst dst;
62
63         /* modified structure members in the end */
64         unsigned long expires;          /* precalculated expiry time */
65         struct {
66                 unsigned long prev;     /* last modification */
67                 u_int32_t credit;
68                 u_int32_t credit_cap, cost;
69         } rateinfo;
70 };
71
72 struct xt_hashlimit_htable {
73         struct hlist_node node;         /* global list of all htables */
74         atomic_t use;
75         int family;
76
77         struct hashlimit_cfg cfg;       /* config */
78
79         /* used internally */
80         spinlock_t lock;                /* lock for list_head */
81         u_int32_t rnd;                  /* random seed for hash */
82         int rnd_initialized;
83         unsigned int count;             /* number entries in table */
84         struct timer_list timer;        /* timer for gc */
85
86         /* seq_file stuff */
87         struct proc_dir_entry *pde;
88
89         struct hlist_head hash[0];      /* hashtable itself */
90 };
91
92 static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */
93 static DEFINE_MUTEX(hlimit_mutex);      /* additional checkentry protection */
94 static HLIST_HEAD(hashlimit_htables);
95 static struct kmem_cache *hashlimit_cachep __read_mostly;
96
97 static inline bool dst_cmp(const struct dsthash_ent *ent,
98                            const struct dsthash_dst *b)
99 {
100         return !memcmp(&ent->dst, b, sizeof(ent->dst));
101 }
102
103 static u_int32_t
104 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
105 {
106         return jhash(dst, sizeof(*dst), ht->rnd) % ht->cfg.size;
107 }
108
109 static struct dsthash_ent *
110 dsthash_find(const struct xt_hashlimit_htable *ht,
111              const struct dsthash_dst *dst)
112 {
113         struct dsthash_ent *ent;
114         struct hlist_node *pos;
115         u_int32_t hash = hash_dst(ht, dst);
116
117         if (!hlist_empty(&ht->hash[hash])) {
118                 hlist_for_each_entry(ent, pos, &ht->hash[hash], node)
119                         if (dst_cmp(ent, dst))
120                                 return ent;
121         }
122         return NULL;
123 }
124
125 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
126 static struct dsthash_ent *
127 dsthash_alloc_init(struct xt_hashlimit_htable *ht,
128                    const struct dsthash_dst *dst)
129 {
130         struct dsthash_ent *ent;
131
132         /* initialize hash with random val at the time we allocate
133          * the first hashtable entry */
134         if (!ht->rnd_initialized) {
135                 get_random_bytes(&ht->rnd, 4);
136                 ht->rnd_initialized = 1;
137         }
138
139         if (ht->cfg.max && ht->count >= ht->cfg.max) {
140                 /* FIXME: do something. question is what.. */
141                 if (net_ratelimit())
142                         printk(KERN_WARNING
143                                 "xt_hashlimit: max count of %u reached\n",
144                                 ht->cfg.max);
145                 return NULL;
146         }
147
148         ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
149         if (!ent) {
150                 if (net_ratelimit())
151                         printk(KERN_ERR
152                                 "xt_hashlimit: can't allocate dsthash_ent\n");
153                 return NULL;
154         }
155         memcpy(&ent->dst, dst, sizeof(ent->dst));
156
157         hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
158         ht->count++;
159         return ent;
160 }
161
162 static inline void
163 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
164 {
165         hlist_del(&ent->node);
166         kmem_cache_free(hashlimit_cachep, ent);
167         ht->count--;
168 }
169 static void htable_gc(unsigned long htlong);
170
171 static int htable_create(struct xt_hashlimit_info *minfo, int family)
172 {
173         struct xt_hashlimit_htable *hinfo;
174         unsigned int size;
175         unsigned int i;
176
177         if (minfo->cfg.size)
178                 size = minfo->cfg.size;
179         else {
180                 size = ((num_physpages << PAGE_SHIFT) / 16384) /
181                        sizeof(struct list_head);
182                 if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
183                         size = 8192;
184                 if (size < 16)
185                         size = 16;
186         }
187         /* FIXME: don't use vmalloc() here or anywhere else -HW */
188         hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
189                         sizeof(struct list_head) * size);
190         if (!hinfo) {
191                 printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
192                 return -1;
193         }
194         minfo->hinfo = hinfo;
195
196         /* copy match config into hashtable config */
197         memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
198         hinfo->cfg.size = size;
199         if (!hinfo->cfg.max)
200                 hinfo->cfg.max = 8 * hinfo->cfg.size;
201         else if (hinfo->cfg.max < hinfo->cfg.size)
202                 hinfo->cfg.max = hinfo->cfg.size;
203
204         for (i = 0; i < hinfo->cfg.size; i++)
205                 INIT_HLIST_HEAD(&hinfo->hash[i]);
206
207         atomic_set(&hinfo->use, 1);
208         hinfo->count = 0;
209         hinfo->family = family;
210         hinfo->rnd_initialized = 0;
211         spin_lock_init(&hinfo->lock);
212         hinfo->pde = create_proc_entry(minfo->name, 0,
213                                        family == AF_INET ? hashlimit_procdir4 :
214                                                            hashlimit_procdir6);
215         if (!hinfo->pde) {
216                 vfree(hinfo);
217                 return -1;
218         }
219         hinfo->pde->proc_fops = &dl_file_ops;
220         hinfo->pde->data = hinfo;
221
222         setup_timer(&hinfo->timer, htable_gc, (unsigned long )hinfo);
223         hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
224         add_timer(&hinfo->timer);
225
226         spin_lock_bh(&hashlimit_lock);
227         hlist_add_head(&hinfo->node, &hashlimit_htables);
228         spin_unlock_bh(&hashlimit_lock);
229
230         return 0;
231 }
232
233 static bool select_all(const struct xt_hashlimit_htable *ht,
234                        const struct dsthash_ent *he)
235 {
236         return 1;
237 }
238
239 static bool select_gc(const struct xt_hashlimit_htable *ht,
240                       const struct dsthash_ent *he)
241 {
242         return jiffies >= he->expires;
243 }
244
245 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
246                         bool (*select)(const struct xt_hashlimit_htable *ht,
247                                       const struct dsthash_ent *he))
248 {
249         unsigned int i;
250
251         /* lock hash table and iterate over it */
252         spin_lock_bh(&ht->lock);
253         for (i = 0; i < ht->cfg.size; i++) {
254                 struct dsthash_ent *dh;
255                 struct hlist_node *pos, *n;
256                 hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
257                         if ((*select)(ht, dh))
258                                 dsthash_free(ht, dh);
259                 }
260         }
261         spin_unlock_bh(&ht->lock);
262 }
263
264 /* hash table garbage collector, run by timer */
265 static void htable_gc(unsigned long htlong)
266 {
267         struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
268
269         htable_selective_cleanup(ht, select_gc);
270
271         /* re-add the timer accordingly */
272         ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
273         add_timer(&ht->timer);
274 }
275
276 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
277 {
278         /* remove timer, if it is pending */
279         if (timer_pending(&hinfo->timer))
280                 del_timer(&hinfo->timer);
281
282         /* remove proc entry */
283         remove_proc_entry(hinfo->pde->name,
284                           hinfo->family == AF_INET ? hashlimit_procdir4 :
285                                                      hashlimit_procdir6);
286         htable_selective_cleanup(hinfo, select_all);
287         vfree(hinfo);
288 }
289
290 static struct xt_hashlimit_htable *htable_find_get(const char *name,
291                                                    int family)
292 {
293         struct xt_hashlimit_htable *hinfo;
294         struct hlist_node *pos;
295
296         spin_lock_bh(&hashlimit_lock);
297         hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
298                 if (!strcmp(name, hinfo->pde->name) &&
299                     hinfo->family == family) {
300                         atomic_inc(&hinfo->use);
301                         spin_unlock_bh(&hashlimit_lock);
302                         return hinfo;
303                 }
304         }
305         spin_unlock_bh(&hashlimit_lock);
306         return NULL;
307 }
308
309 static void htable_put(struct xt_hashlimit_htable *hinfo)
310 {
311         if (atomic_dec_and_test(&hinfo->use)) {
312                 spin_lock_bh(&hashlimit_lock);
313                 hlist_del(&hinfo->node);
314                 spin_unlock_bh(&hashlimit_lock);
315                 htable_destroy(hinfo);
316         }
317 }
318
319 /* The algorithm used is the Simple Token Bucket Filter (TBF)
320  * see net/sched/sch_tbf.c in the linux source tree
321  */
322
323 /* Rusty: This is my (non-mathematically-inclined) understanding of
324    this algorithm.  The `average rate' in jiffies becomes your initial
325    amount of credit `credit' and the most credit you can ever have
326    `credit_cap'.  The `peak rate' becomes the cost of passing the
327    test, `cost'.
328
329    `prev' tracks the last packet hit: you gain one credit per jiffy.
330    If you get credit balance more than this, the extra credit is
331    discarded.  Every time the match passes, you lose `cost' credits;
332    if you don't have that many, the test fails.
333
334    See Alexey's formal explanation in net/sched/sch_tbf.c.
335
336    To get the maximum range, we multiply by this factor (ie. you get N
337    credits per jiffy).  We want to allow a rate as low as 1 per day
338    (slowest userspace tool allows), which means
339    CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
340 */
341 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
342
343 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
344  * us the power of 2 below the theoretical max, so GCC simply does a
345  * shift. */
346 #define _POW2_BELOW2(x) ((x)|((x)>>1))
347 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
348 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
349 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
350 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
351 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
352
353 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
354
355 /* Precision saver. */
356 static inline u_int32_t
357 user2credits(u_int32_t user)
358 {
359         /* If multiplying would overflow... */
360         if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
361                 /* Divide first. */
362                 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
363
364         return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
365 }
366
367 static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
368 {
369         dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
370         if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
371                 dh->rateinfo.credit = dh->rateinfo.credit_cap;
372         dh->rateinfo.prev = now;
373 }
374
375 static int
376 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
377                    struct dsthash_dst *dst,
378                    const struct sk_buff *skb, unsigned int protoff)
379 {
380         __be16 _ports[2], *ports;
381         int nexthdr;
382
383         memset(dst, 0, sizeof(*dst));
384
385         switch (hinfo->family) {
386         case AF_INET:
387                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
388                         dst->addr.ip.dst = ip_hdr(skb)->daddr;
389                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
390                         dst->addr.ip.src = ip_hdr(skb)->saddr;
391
392                 if (!(hinfo->cfg.mode &
393                       (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
394                         return 0;
395                 nexthdr = ip_hdr(skb)->protocol;
396                 break;
397 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
398         case AF_INET6:
399                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
400                         memcpy(&dst->addr.ip6.dst, &ipv6_hdr(skb)->daddr,
401                                sizeof(dst->addr.ip6.dst));
402                 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
403                         memcpy(&dst->addr.ip6.src, &ipv6_hdr(skb)->saddr,
404                                sizeof(dst->addr.ip6.src));
405
406                 if (!(hinfo->cfg.mode &
407                       (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
408                         return 0;
409                 nexthdr = ipv6_find_hdr(skb, &protoff, -1, NULL);
410                 if (nexthdr < 0)
411                         return -1;
412                 break;
413 #endif
414         default:
415                 BUG();
416                 return 0;
417         }
418
419         switch (nexthdr) {
420         case IPPROTO_TCP:
421         case IPPROTO_UDP:
422         case IPPROTO_UDPLITE:
423         case IPPROTO_SCTP:
424         case IPPROTO_DCCP:
425                 ports = skb_header_pointer(skb, protoff, sizeof(_ports),
426                                            &_ports);
427                 break;
428         default:
429                 _ports[0] = _ports[1] = 0;
430                 ports = _ports;
431                 break;
432         }
433         if (!ports)
434                 return -1;
435         if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
436                 dst->src_port = ports[0];
437         if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
438                 dst->dst_port = ports[1];
439         return 0;
440 }
441
442 static bool
443 hashlimit_match(const struct sk_buff *skb,
444                 const struct net_device *in,
445                 const struct net_device *out,
446                 const struct xt_match *match,
447                 const void *matchinfo,
448                 int offset,
449                 unsigned int protoff,
450                 bool *hotdrop)
451 {
452         const struct xt_hashlimit_info *r =
453                 ((const struct xt_hashlimit_info *)matchinfo)->u.master;
454         struct xt_hashlimit_htable *hinfo = r->hinfo;
455         unsigned long now = jiffies;
456         struct dsthash_ent *dh;
457         struct dsthash_dst dst;
458
459         if (hashlimit_init_dst(hinfo, &dst, skb, protoff) < 0)
460                 goto hotdrop;
461
462         spin_lock_bh(&hinfo->lock);
463         dh = dsthash_find(hinfo, &dst);
464         if (!dh) {
465                 dh = dsthash_alloc_init(hinfo, &dst);
466                 if (!dh) {
467                         spin_unlock_bh(&hinfo->lock);
468                         goto hotdrop;
469                 }
470
471                 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
472                 dh->rateinfo.prev = jiffies;
473                 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
474                                                    hinfo->cfg.burst);
475                 dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
476                                                        hinfo->cfg.burst);
477                 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
478         } else {
479                 /* update expiration timeout */
480                 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
481                 rateinfo_recalc(dh, now);
482         }
483
484         if (dh->rateinfo.credit >= dh->rateinfo.cost) {
485                 /* We're underlimit. */
486                 dh->rateinfo.credit -= dh->rateinfo.cost;
487                 spin_unlock_bh(&hinfo->lock);
488                 return true;
489         }
490
491         spin_unlock_bh(&hinfo->lock);
492
493         /* default case: we're overlimit, thus don't match */
494         return false;
495
496 hotdrop:
497         *hotdrop = true;
498         return false;
499 }
500
501 static bool
502 hashlimit_checkentry(const char *tablename,
503                      const void *inf,
504                      const struct xt_match *match,
505                      void *matchinfo,
506                      unsigned int hook_mask)
507 {
508         struct xt_hashlimit_info *r = matchinfo;
509
510         /* Check for overflow. */
511         if (r->cfg.burst == 0 ||
512             user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
513                 printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
514                        r->cfg.avg, r->cfg.burst);
515                 return false;
516         }
517         if (r->cfg.mode == 0 ||
518             r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
519                            XT_HASHLIMIT_HASH_DIP |
520                            XT_HASHLIMIT_HASH_SIP |
521                            XT_HASHLIMIT_HASH_SPT))
522                 return false;
523         if (!r->cfg.gc_interval)
524                 return false;
525         if (!r->cfg.expire)
526                 return false;
527         if (r->name[sizeof(r->name) - 1] != '\0')
528                 return false;
529
530         /* This is the best we've got: We cannot release and re-grab lock,
531          * since checkentry() is called before x_tables.c grabs xt_mutex.
532          * We also cannot grab the hashtable spinlock, since htable_create will
533          * call vmalloc, and that can sleep.  And we cannot just re-search
534          * the list of htable's in htable_create(), since then we would
535          * create duplicate proc files. -HW */
536         mutex_lock(&hlimit_mutex);
537         r->hinfo = htable_find_get(r->name, match->family);
538         if (!r->hinfo && htable_create(r, match->family) != 0) {
539                 mutex_unlock(&hlimit_mutex);
540                 return false;
541         }
542         mutex_unlock(&hlimit_mutex);
543
544         /* Ugly hack: For SMP, we only want to use one set */
545         r->u.master = r;
546         return true;
547 }
548
549 static void
550 hashlimit_destroy(const struct xt_match *match, void *matchinfo)
551 {
552         const struct xt_hashlimit_info *r = matchinfo;
553
554         htable_put(r->hinfo);
555 }
556
557 #ifdef CONFIG_COMPAT
558 struct compat_xt_hashlimit_info {
559         char name[IFNAMSIZ];
560         struct hashlimit_cfg cfg;
561         compat_uptr_t hinfo;
562         compat_uptr_t master;
563 };
564
565 static void compat_from_user(void *dst, void *src)
566 {
567         int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
568
569         memcpy(dst, src, off);
570         memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
571 }
572
573 static int compat_to_user(void __user *dst, void *src)
574 {
575         int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
576
577         return copy_to_user(dst, src, off) ? -EFAULT : 0;
578 }
579 #endif
580
581 static struct xt_match xt_hashlimit[] __read_mostly = {
582         {
583                 .name           = "hashlimit",
584                 .family         = AF_INET,
585                 .match          = hashlimit_match,
586                 .matchsize      = sizeof(struct xt_hashlimit_info),
587 #ifdef CONFIG_COMPAT
588                 .compatsize     = sizeof(struct compat_xt_hashlimit_info),
589                 .compat_from_user = compat_from_user,
590                 .compat_to_user = compat_to_user,
591 #endif
592                 .checkentry     = hashlimit_checkentry,
593                 .destroy        = hashlimit_destroy,
594                 .me             = THIS_MODULE
595         },
596         {
597                 .name           = "hashlimit",
598                 .family         = AF_INET6,
599                 .match          = hashlimit_match,
600                 .matchsize      = sizeof(struct xt_hashlimit_info),
601 #ifdef CONFIG_COMPAT
602                 .compatsize     = sizeof(struct compat_xt_hashlimit_info),
603                 .compat_from_user = compat_from_user,
604                 .compat_to_user = compat_to_user,
605 #endif
606                 .checkentry     = hashlimit_checkentry,
607                 .destroy        = hashlimit_destroy,
608                 .me             = THIS_MODULE
609         },
610 };
611
612 /* PROC stuff */
613 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
614 {
615         struct proc_dir_entry *pde = s->private;
616         struct xt_hashlimit_htable *htable = pde->data;
617         unsigned int *bucket;
618
619         spin_lock_bh(&htable->lock);
620         if (*pos >= htable->cfg.size)
621                 return NULL;
622
623         bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
624         if (!bucket)
625                 return ERR_PTR(-ENOMEM);
626
627         *bucket = *pos;
628         return bucket;
629 }
630
631 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
632 {
633         struct proc_dir_entry *pde = s->private;
634         struct xt_hashlimit_htable *htable = pde->data;
635         unsigned int *bucket = (unsigned int *)v;
636
637         *pos = ++(*bucket);
638         if (*pos >= htable->cfg.size) {
639                 kfree(v);
640                 return NULL;
641         }
642         return bucket;
643 }
644
645 static void dl_seq_stop(struct seq_file *s, void *v)
646 {
647         struct proc_dir_entry *pde = s->private;
648         struct xt_hashlimit_htable *htable = pde->data;
649         unsigned int *bucket = (unsigned int *)v;
650
651         kfree(bucket);
652         spin_unlock_bh(&htable->lock);
653 }
654
655 static int dl_seq_real_show(struct dsthash_ent *ent, int family,
656                                    struct seq_file *s)
657 {
658         /* recalculate to show accurate numbers */
659         rateinfo_recalc(ent, jiffies);
660
661         switch (family) {
662         case AF_INET:
663                 return seq_printf(s, "%ld %u.%u.%u.%u:%u->"
664                                      "%u.%u.%u.%u:%u %u %u %u\n",
665                                  (long)(ent->expires - jiffies)/HZ,
666                                  NIPQUAD(ent->dst.addr.ip.src),
667                                  ntohs(ent->dst.src_port),
668                                  NIPQUAD(ent->dst.addr.ip.dst),
669                                  ntohs(ent->dst.dst_port),
670                                  ent->rateinfo.credit, ent->rateinfo.credit_cap,
671                                  ent->rateinfo.cost);
672         case AF_INET6:
673                 return seq_printf(s, "%ld " NIP6_FMT ":%u->"
674                                      NIP6_FMT ":%u %u %u %u\n",
675                                  (long)(ent->expires - jiffies)/HZ,
676                                  NIP6(*(struct in6_addr *)&ent->dst.addr.ip6.src),
677                                  ntohs(ent->dst.src_port),
678                                  NIP6(*(struct in6_addr *)&ent->dst.addr.ip6.dst),
679                                  ntohs(ent->dst.dst_port),
680                                  ent->rateinfo.credit, ent->rateinfo.credit_cap,
681                                  ent->rateinfo.cost);
682         default:
683                 BUG();
684                 return 0;
685         }
686 }
687
688 static int dl_seq_show(struct seq_file *s, void *v)
689 {
690         struct proc_dir_entry *pde = s->private;
691         struct xt_hashlimit_htable *htable = pde->data;
692         unsigned int *bucket = (unsigned int *)v;
693         struct dsthash_ent *ent;
694         struct hlist_node *pos;
695
696         if (!hlist_empty(&htable->hash[*bucket])) {
697                 hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
698                         if (dl_seq_real_show(ent, htable->family, s))
699                                 return 1;
700         }
701         return 0;
702 }
703
704 static const struct seq_operations dl_seq_ops = {
705         .start = dl_seq_start,
706         .next  = dl_seq_next,
707         .stop  = dl_seq_stop,
708         .show  = dl_seq_show
709 };
710
711 static int dl_proc_open(struct inode *inode, struct file *file)
712 {
713         int ret = seq_open(file, &dl_seq_ops);
714
715         if (!ret) {
716                 struct seq_file *sf = file->private_data;
717                 sf->private = PDE(inode);
718         }
719         return ret;
720 }
721
722 static const struct file_operations dl_file_ops = {
723         .owner   = THIS_MODULE,
724         .open    = dl_proc_open,
725         .read    = seq_read,
726         .llseek  = seq_lseek,
727         .release = seq_release
728 };
729
730 static int __init xt_hashlimit_init(void)
731 {
732         int err;
733
734         err = xt_register_matches(xt_hashlimit, ARRAY_SIZE(xt_hashlimit));
735         if (err < 0)
736                 goto err1;
737
738         err = -ENOMEM;
739         hashlimit_cachep = kmem_cache_create("xt_hashlimit",
740                                             sizeof(struct dsthash_ent), 0, 0,
741                                             NULL, NULL);
742         if (!hashlimit_cachep) {
743                 printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
744                 goto err2;
745         }
746         hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", proc_net);
747         if (!hashlimit_procdir4) {
748                 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
749                                 "entry\n");
750                 goto err3;
751         }
752         hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", proc_net);
753         if (!hashlimit_procdir6) {
754                 printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
755                                 "entry\n");
756                 goto err4;
757         }
758         return 0;
759 err4:
760         remove_proc_entry("ipt_hashlimit", proc_net);
761 err3:
762         kmem_cache_destroy(hashlimit_cachep);
763 err2:
764         xt_unregister_matches(xt_hashlimit, ARRAY_SIZE(xt_hashlimit));
765 err1:
766         return err;
767
768 }
769
770 static void __exit xt_hashlimit_fini(void)
771 {
772         remove_proc_entry("ipt_hashlimit", proc_net);
773         remove_proc_entry("ip6t_hashlimit", proc_net);
774         kmem_cache_destroy(hashlimit_cachep);
775         xt_unregister_matches(xt_hashlimit, ARRAY_SIZE(xt_hashlimit));
776 }
777
778 module_init(xt_hashlimit_init);
779 module_exit(xt_hashlimit_fini);