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ipvs: count pre-established TCP states as active
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / netfilter / xt_hashlimit.c
1 /*
2 * xt_hashlimit - Netfilter module to limit the number of packets per time
3 * separately for each hashbucket (sourceip/sourceport/dstip/dstport)
4 *
5 * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
6 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
7 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
8 *
9 * Development of this code was funded by Astaro AG, http://www.astaro.com/
10 */
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 #include <linux/module.h>
13 #include <linux/spinlock.h>
14 #include <linux/random.h>
15 #include <linux/jhash.h>
16 #include <linux/slab.h>
17 #include <linux/vmalloc.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/list.h>
21 #include <linux/skbuff.h>
22 #include <linux/mm.h>
23 #include <linux/in.h>
24 #include <linux/ip.h>
25 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
26 #include <linux/ipv6.h>
27 #include <net/ipv6.h>
28 #endif
29
30 #include <net/net_namespace.h>
31 #include <net/netns/generic.h>
32
33 #include <linux/netfilter/x_tables.h>
34 #include <linux/netfilter_ipv4/ip_tables.h>
35 #include <linux/netfilter_ipv6/ip6_tables.h>
36 #include <linux/netfilter/xt_hashlimit.h>
37 #include <linux/mutex.h>
38
39 MODULE_LICENSE("GPL");
40 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
41 MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
42 MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
43 MODULE_ALIAS("ipt_hashlimit");
44 MODULE_ALIAS("ip6t_hashlimit");
45
46 struct hashlimit_net {
47 struct hlist_head htables;
48 struct proc_dir_entry *ipt_hashlimit;
49 struct proc_dir_entry *ip6t_hashlimit;
50 };
51
52 static int hashlimit_net_id;
53 static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
54 {
55 return net_generic(net, hashlimit_net_id);
56 }
57
58 /* need to declare this at the top */
59 static const struct file_operations dl_file_ops;
60
61 /* hash table crap */
62 struct dsthash_dst {
63 union {
64 struct {
65 __be32 src;
66 __be32 dst;
67 } ip;
68 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
69 struct {
70 __be32 src[4];
71 __be32 dst[4];
72 } ip6;
73 #endif
74 };
75 __be16 src_port;
76 __be16 dst_port;
77 };
78
79 struct dsthash_ent {
80 /* static / read-only parts in the beginning */
81 struct hlist_node node;
82 struct dsthash_dst dst;
83
84 /* modified structure members in the end */
85 spinlock_t lock;
86 unsigned long expires; /* precalculated expiry time */
87 struct {
88 unsigned long prev; /* last modification */
89 u_int32_t credit;
90 u_int32_t credit_cap, cost;
91 } rateinfo;
92 struct rcu_head rcu;
93 };
94
95 struct xt_hashlimit_htable {
96 struct hlist_node node; /* global list of all htables */
97 int use;
98 u_int8_t family;
99 bool rnd_initialized;
100
101 struct hashlimit_cfg1 cfg; /* config */
102
103 /* used internally */
104 spinlock_t lock; /* lock for list_head */
105 u_int32_t rnd; /* random seed for hash */
106 unsigned int count; /* number entries in table */
107 struct timer_list timer; /* timer for gc */
108
109 /* seq_file stuff */
110 struct proc_dir_entry *pde;
111 const char *name;
112 struct net *net;
113
114 struct hlist_head hash[0]; /* hashtable itself */
115 };
116
117 static DEFINE_MUTEX(hashlimit_mutex); /* protects htables list */
118 static struct kmem_cache *hashlimit_cachep __read_mostly;
119
120 static inline bool dst_cmp(const struct dsthash_ent *ent,
121 const struct dsthash_dst *b)
122 {
123 return !memcmp(&ent->dst, b, sizeof(ent->dst));
124 }
125
126 static u_int32_t
127 hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
128 {
129 u_int32_t hash = jhash2((const u32 *)dst,
130 sizeof(*dst)/sizeof(u32),
131 ht->rnd);
132 /*
133 * Instead of returning hash % ht->cfg.size (implying a divide)
134 * we return the high 32 bits of the (hash * ht->cfg.size) that will
135 * give results between [0 and cfg.size-1] and same hash distribution,
136 * but using a multiply, less expensive than a divide
137 */
138 return ((u64)hash * ht->cfg.size) >> 32;
139 }
140
141 static struct dsthash_ent *
142 dsthash_find(const struct xt_hashlimit_htable *ht,
143 const struct dsthash_dst *dst)
144 {
145 struct dsthash_ent *ent;
146 u_int32_t hash = hash_dst(ht, dst);
147
148 if (!hlist_empty(&ht->hash[hash])) {
149 hlist_for_each_entry_rcu(ent, &ht->hash[hash], node)
150 if (dst_cmp(ent, dst)) {
151 spin_lock(&ent->lock);
152 return ent;
153 }
154 }
155 return NULL;
156 }
157
158 /* allocate dsthash_ent, initialize dst, put in htable and lock it */
159 static struct dsthash_ent *
160 dsthash_alloc_init(struct xt_hashlimit_htable *ht,
161 const struct dsthash_dst *dst, bool *race)
162 {
163 struct dsthash_ent *ent;
164
165 spin_lock(&ht->lock);
166
167 /* Two or more packets may race to create the same entry in the
168 * hashtable, double check if this packet lost race.
169 */
170 ent = dsthash_find(ht, dst);
171 if (ent != NULL) {
172 spin_unlock(&ht->lock);
173 *race = true;
174 return ent;
175 }
176
177 /* initialize hash with random val at the time we allocate
178 * the first hashtable entry */
179 if (unlikely(!ht->rnd_initialized)) {
180 get_random_bytes(&ht->rnd, sizeof(ht->rnd));
181 ht->rnd_initialized = true;
182 }
183
184 if (ht->cfg.max && ht->count >= ht->cfg.max) {
185 /* FIXME: do something. question is what.. */
186 net_err_ratelimited("max count of %u reached\n", ht->cfg.max);
187 ent = NULL;
188 } else
189 ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
190 if (ent) {
191 memcpy(&ent->dst, dst, sizeof(ent->dst));
192 spin_lock_init(&ent->lock);
193
194 spin_lock(&ent->lock);
195 hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]);
196 ht->count++;
197 }
198 spin_unlock(&ht->lock);
199 return ent;
200 }
201
202 static void dsthash_free_rcu(struct rcu_head *head)
203 {
204 struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
205
206 kmem_cache_free(hashlimit_cachep, ent);
207 }
208
209 static inline void
210 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
211 {
212 hlist_del_rcu(&ent->node);
213 call_rcu_bh(&ent->rcu, dsthash_free_rcu);
214 ht->count--;
215 }
216 static void htable_gc(unsigned long htlong);
217
218 static int htable_create(struct net *net, struct xt_hashlimit_mtinfo1 *minfo,
219 u_int8_t family)
220 {
221 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
222 struct xt_hashlimit_htable *hinfo;
223 unsigned int size;
224 unsigned int i;
225
226 if (minfo->cfg.size) {
227 size = minfo->cfg.size;
228 } else {
229 size = (totalram_pages << PAGE_SHIFT) / 16384 /
230 sizeof(struct list_head);
231 if (totalram_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
232 size = 8192;
233 if (size < 16)
234 size = 16;
235 }
236 /* FIXME: don't use vmalloc() here or anywhere else -HW */
237 hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
238 sizeof(struct list_head) * size);
239 if (hinfo == NULL)
240 return -ENOMEM;
241 minfo->hinfo = hinfo;
242
243 /* copy match config into hashtable config */
244 memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
245 hinfo->cfg.size = size;
246 if (hinfo->cfg.max == 0)
247 hinfo->cfg.max = 8 * hinfo->cfg.size;
248 else if (hinfo->cfg.max < hinfo->cfg.size)
249 hinfo->cfg.max = hinfo->cfg.size;
250
251 for (i = 0; i < hinfo->cfg.size; i++)
252 INIT_HLIST_HEAD(&hinfo->hash[i]);
253
254 hinfo->use = 1;
255 hinfo->count = 0;
256 hinfo->family = family;
257 hinfo->rnd_initialized = false;
258 hinfo->name = kstrdup(minfo->name, GFP_KERNEL);
259 if (!hinfo->name) {
260 vfree(hinfo);
261 return -ENOMEM;
262 }
263 spin_lock_init(&hinfo->lock);
264
265 hinfo->pde = proc_create_data(minfo->name, 0,
266 (family == NFPROTO_IPV4) ?
267 hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
268 &dl_file_ops, hinfo);
269 if (hinfo->pde == NULL) {
270 kfree(hinfo->name);
271 vfree(hinfo);
272 return -ENOMEM;
273 }
274 hinfo->net = net;
275
276 setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo);
277 hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
278 add_timer(&hinfo->timer);
279
280 hlist_add_head(&hinfo->node, &hashlimit_net->htables);
281
282 return 0;
283 }
284
285 static bool select_all(const struct xt_hashlimit_htable *ht,
286 const struct dsthash_ent *he)
287 {
288 return 1;
289 }
290
291 static bool select_gc(const struct xt_hashlimit_htable *ht,
292 const struct dsthash_ent *he)
293 {
294 return time_after_eq(jiffies, he->expires);
295 }
296
297 static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
298 bool (*select)(const struct xt_hashlimit_htable *ht,
299 const struct dsthash_ent *he))
300 {
301 unsigned int i;
302
303 /* lock hash table and iterate over it */
304 spin_lock_bh(&ht->lock);
305 for (i = 0; i < ht->cfg.size; i++) {
306 struct dsthash_ent *dh;
307 struct hlist_node *n;
308 hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) {
309 if ((*select)(ht, dh))
310 dsthash_free(ht, dh);
311 }
312 }
313 spin_unlock_bh(&ht->lock);
314 }
315
316 /* hash table garbage collector, run by timer */
317 static void htable_gc(unsigned long htlong)
318 {
319 struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
320
321 htable_selective_cleanup(ht, select_gc);
322
323 /* re-add the timer accordingly */
324 ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
325 add_timer(&ht->timer);
326 }
327
328 static void htable_destroy(struct xt_hashlimit_htable *hinfo)
329 {
330 struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
331 struct proc_dir_entry *parent;
332
333 del_timer_sync(&hinfo->timer);
334
335 if (hinfo->family == NFPROTO_IPV4)
336 parent = hashlimit_net->ipt_hashlimit;
337 else
338 parent = hashlimit_net->ip6t_hashlimit;
339
340 if(parent != NULL)
341 remove_proc_entry(hinfo->name, parent);
342
343 htable_selective_cleanup(hinfo, select_all);
344 kfree(hinfo->name);
345 vfree(hinfo);
346 }
347
348 static struct xt_hashlimit_htable *htable_find_get(struct net *net,
349 const char *name,
350 u_int8_t family)
351 {
352 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
353 struct xt_hashlimit_htable *hinfo;
354
355 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
356 if (!strcmp(name, hinfo->name) &&
357 hinfo->family == family) {
358 hinfo->use++;
359 return hinfo;
360 }
361 }
362 return NULL;
363 }
364
365 static void htable_put(struct xt_hashlimit_htable *hinfo)
366 {
367 mutex_lock(&hashlimit_mutex);
368 if (--hinfo->use == 0) {
369 hlist_del(&hinfo->node);
370 htable_destroy(hinfo);
371 }
372 mutex_unlock(&hashlimit_mutex);
373 }
374
375 /* The algorithm used is the Simple Token Bucket Filter (TBF)
376 * see net/sched/sch_tbf.c in the linux source tree
377 */
378
379 /* Rusty: This is my (non-mathematically-inclined) understanding of
380 this algorithm. The `average rate' in jiffies becomes your initial
381 amount of credit `credit' and the most credit you can ever have
382 `credit_cap'. The `peak rate' becomes the cost of passing the
383 test, `cost'.
384
385 `prev' tracks the last packet hit: you gain one credit per jiffy.
386 If you get credit balance more than this, the extra credit is
387 discarded. Every time the match passes, you lose `cost' credits;
388 if you don't have that many, the test fails.
389
390 See Alexey's formal explanation in net/sched/sch_tbf.c.
391
392 To get the maximum range, we multiply by this factor (ie. you get N
393 credits per jiffy). We want to allow a rate as low as 1 per day
394 (slowest userspace tool allows), which means
395 CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
396 */
397 #define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
398
399 /* Repeated shift and or gives us all 1s, final shift and add 1 gives
400 * us the power of 2 below the theoretical max, so GCC simply does a
401 * shift. */
402 #define _POW2_BELOW2(x) ((x)|((x)>>1))
403 #define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
404 #define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
405 #define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
406 #define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
407 #define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
408
409 #define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
410
411 /* in byte mode, the lowest possible rate is one packet/second.
412 * credit_cap is used as a counter that tells us how many times we can
413 * refill the "credits available" counter when it becomes empty.
414 */
415 #define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
416 #define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
417
418 static u32 xt_hashlimit_len_to_chunks(u32 len)
419 {
420 return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
421 }
422
423 /* Precision saver. */
424 static u32 user2credits(u32 user)
425 {
426 /* If multiplying would overflow... */
427 if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
428 /* Divide first. */
429 return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
430
431 return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
432 }
433
434 static u32 user2credits_byte(u32 user)
435 {
436 u64 us = user;
437 us *= HZ * CREDITS_PER_JIFFY_BYTES;
438 return (u32) (us >> 32);
439 }
440
441 static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now, u32 mode)
442 {
443 unsigned long delta = now - dh->rateinfo.prev;
444 u32 cap;
445
446 if (delta == 0)
447 return;
448
449 dh->rateinfo.prev = now;
450
451 if (mode & XT_HASHLIMIT_BYTES) {
452 u32 tmp = dh->rateinfo.credit;
453 dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
454 cap = CREDITS_PER_JIFFY_BYTES * HZ;
455 if (tmp >= dh->rateinfo.credit) {/* overflow */
456 dh->rateinfo.credit = cap;
457 return;
458 }
459 } else {
460 dh->rateinfo.credit += delta * CREDITS_PER_JIFFY;
461 cap = dh->rateinfo.credit_cap;
462 }
463 if (dh->rateinfo.credit > cap)
464 dh->rateinfo.credit = cap;
465 }
466
467 static void rateinfo_init(struct dsthash_ent *dh,
468 struct xt_hashlimit_htable *hinfo)
469 {
470 dh->rateinfo.prev = jiffies;
471 if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
472 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
473 dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg);
474 dh->rateinfo.credit_cap = hinfo->cfg.burst;
475 } else {
476 dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
477 hinfo->cfg.burst);
478 dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
479 dh->rateinfo.credit_cap = dh->rateinfo.credit;
480 }
481 }
482
483 static inline __be32 maskl(__be32 a, unsigned int l)
484 {
485 return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
486 }
487
488 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
489 static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
490 {
491 switch (p) {
492 case 0 ... 31:
493 i[0] = maskl(i[0], p);
494 i[1] = i[2] = i[3] = 0;
495 break;
496 case 32 ... 63:
497 i[1] = maskl(i[1], p - 32);
498 i[2] = i[3] = 0;
499 break;
500 case 64 ... 95:
501 i[2] = maskl(i[2], p - 64);
502 i[3] = 0;
503 break;
504 case 96 ... 127:
505 i[3] = maskl(i[3], p - 96);
506 break;
507 case 128:
508 break;
509 }
510 }
511 #endif
512
513 static int
514 hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
515 struct dsthash_dst *dst,
516 const struct sk_buff *skb, unsigned int protoff)
517 {
518 __be16 _ports[2], *ports;
519 u8 nexthdr;
520 int poff;
521
522 memset(dst, 0, sizeof(*dst));
523
524 switch (hinfo->family) {
525 case NFPROTO_IPV4:
526 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
527 dst->ip.dst = maskl(ip_hdr(skb)->daddr,
528 hinfo->cfg.dstmask);
529 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
530 dst->ip.src = maskl(ip_hdr(skb)->saddr,
531 hinfo->cfg.srcmask);
532
533 if (!(hinfo->cfg.mode &
534 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
535 return 0;
536 nexthdr = ip_hdr(skb)->protocol;
537 break;
538 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
539 case NFPROTO_IPV6:
540 {
541 __be16 frag_off;
542
543 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
544 memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
545 sizeof(dst->ip6.dst));
546 hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
547 }
548 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
549 memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
550 sizeof(dst->ip6.src));
551 hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
552 }
553
554 if (!(hinfo->cfg.mode &
555 (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
556 return 0;
557 nexthdr = ipv6_hdr(skb)->nexthdr;
558 protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off);
559 if ((int)protoff < 0)
560 return -1;
561 break;
562 }
563 #endif
564 default:
565 BUG();
566 return 0;
567 }
568
569 poff = proto_ports_offset(nexthdr);
570 if (poff >= 0) {
571 ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
572 &_ports);
573 } else {
574 _ports[0] = _ports[1] = 0;
575 ports = _ports;
576 }
577 if (!ports)
578 return -1;
579 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
580 dst->src_port = ports[0];
581 if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
582 dst->dst_port = ports[1];
583 return 0;
584 }
585
586 static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
587 {
588 u64 tmp = xt_hashlimit_len_to_chunks(len);
589 tmp = tmp * dh->rateinfo.cost;
590
591 if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
592 tmp = CREDITS_PER_JIFFY_BYTES * HZ;
593
594 if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
595 dh->rateinfo.credit_cap--;
596 dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
597 }
598 return (u32) tmp;
599 }
600
601 static bool
602 hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
603 {
604 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
605 struct xt_hashlimit_htable *hinfo = info->hinfo;
606 unsigned long now = jiffies;
607 struct dsthash_ent *dh;
608 struct dsthash_dst dst;
609 bool race = false;
610 u32 cost;
611
612 if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
613 goto hotdrop;
614
615 rcu_read_lock_bh();
616 dh = dsthash_find(hinfo, &dst);
617 if (dh == NULL) {
618 dh = dsthash_alloc_init(hinfo, &dst, &race);
619 if (dh == NULL) {
620 rcu_read_unlock_bh();
621 goto hotdrop;
622 } else if (race) {
623 /* Already got an entry, update expiration timeout */
624 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
625 rateinfo_recalc(dh, now, hinfo->cfg.mode);
626 } else {
627 dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
628 rateinfo_init(dh, hinfo);
629 }
630 } else {
631 /* update expiration timeout */
632 dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
633 rateinfo_recalc(dh, now, hinfo->cfg.mode);
634 }
635
636 if (info->cfg.mode & XT_HASHLIMIT_BYTES)
637 cost = hashlimit_byte_cost(skb->len, dh);
638 else
639 cost = dh->rateinfo.cost;
640
641 if (dh->rateinfo.credit >= cost) {
642 /* below the limit */
643 dh->rateinfo.credit -= cost;
644 spin_unlock(&dh->lock);
645 rcu_read_unlock_bh();
646 return !(info->cfg.mode & XT_HASHLIMIT_INVERT);
647 }
648
649 spin_unlock(&dh->lock);
650 rcu_read_unlock_bh();
651 /* default match is underlimit - so over the limit, we need to invert */
652 return info->cfg.mode & XT_HASHLIMIT_INVERT;
653
654 hotdrop:
655 par->hotdrop = true;
656 return false;
657 }
658
659 static int hashlimit_mt_check(const struct xt_mtchk_param *par)
660 {
661 struct net *net = par->net;
662 struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
663 int ret;
664
665 if (info->cfg.gc_interval == 0 || info->cfg.expire == 0)
666 return -EINVAL;
667 if (info->name[sizeof(info->name)-1] != '\0')
668 return -EINVAL;
669 if (par->family == NFPROTO_IPV4) {
670 if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32)
671 return -EINVAL;
672 } else {
673 if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128)
674 return -EINVAL;
675 }
676
677 if (info->cfg.mode & ~XT_HASHLIMIT_ALL) {
678 pr_info("Unknown mode mask %X, kernel too old?\n",
679 info->cfg.mode);
680 return -EINVAL;
681 }
682
683 /* Check for overflow. */
684 if (info->cfg.mode & XT_HASHLIMIT_BYTES) {
685 if (user2credits_byte(info->cfg.avg) == 0) {
686 pr_info("overflow, rate too high: %u\n", info->cfg.avg);
687 return -EINVAL;
688 }
689 } else if (info->cfg.burst == 0 ||
690 user2credits(info->cfg.avg * info->cfg.burst) <
691 user2credits(info->cfg.avg)) {
692 pr_info("overflow, try lower: %u/%u\n",
693 info->cfg.avg, info->cfg.burst);
694 return -ERANGE;
695 }
696
697 mutex_lock(&hashlimit_mutex);
698 info->hinfo = htable_find_get(net, info->name, par->family);
699 if (info->hinfo == NULL) {
700 ret = htable_create(net, info, par->family);
701 if (ret < 0) {
702 mutex_unlock(&hashlimit_mutex);
703 return ret;
704 }
705 }
706 mutex_unlock(&hashlimit_mutex);
707 return 0;
708 }
709
710 static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
711 {
712 const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
713
714 htable_put(info->hinfo);
715 }
716
717 static struct xt_match hashlimit_mt_reg[] __read_mostly = {
718 {
719 .name = "hashlimit",
720 .revision = 1,
721 .family = NFPROTO_IPV4,
722 .match = hashlimit_mt,
723 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
724 .checkentry = hashlimit_mt_check,
725 .destroy = hashlimit_mt_destroy,
726 .me = THIS_MODULE,
727 },
728 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
729 {
730 .name = "hashlimit",
731 .revision = 1,
732 .family = NFPROTO_IPV6,
733 .match = hashlimit_mt,
734 .matchsize = sizeof(struct xt_hashlimit_mtinfo1),
735 .checkentry = hashlimit_mt_check,
736 .destroy = hashlimit_mt_destroy,
737 .me = THIS_MODULE,
738 },
739 #endif
740 };
741
742 /* PROC stuff */
743 static void *dl_seq_start(struct seq_file *s, loff_t *pos)
744 __acquires(htable->lock)
745 {
746 struct xt_hashlimit_htable *htable = s->private;
747 unsigned int *bucket;
748
749 spin_lock_bh(&htable->lock);
750 if (*pos >= htable->cfg.size)
751 return NULL;
752
753 bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
754 if (!bucket)
755 return ERR_PTR(-ENOMEM);
756
757 *bucket = *pos;
758 return bucket;
759 }
760
761 static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
762 {
763 struct xt_hashlimit_htable *htable = s->private;
764 unsigned int *bucket = (unsigned int *)v;
765
766 *pos = ++(*bucket);
767 if (*pos >= htable->cfg.size) {
768 kfree(v);
769 return NULL;
770 }
771 return bucket;
772 }
773
774 static void dl_seq_stop(struct seq_file *s, void *v)
775 __releases(htable->lock)
776 {
777 struct xt_hashlimit_htable *htable = s->private;
778 unsigned int *bucket = (unsigned int *)v;
779
780 if (!IS_ERR(bucket))
781 kfree(bucket);
782 spin_unlock_bh(&htable->lock);
783 }
784
785 static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
786 struct seq_file *s)
787 {
788 int res;
789 const struct xt_hashlimit_htable *ht = s->private;
790
791 spin_lock(&ent->lock);
792 /* recalculate to show accurate numbers */
793 rateinfo_recalc(ent, jiffies, ht->cfg.mode);
794
795 switch (family) {
796 case NFPROTO_IPV4:
797 res = seq_printf(s, "%ld %pI4:%u->%pI4:%u %u %u %u\n",
798 (long)(ent->expires - jiffies)/HZ,
799 &ent->dst.ip.src,
800 ntohs(ent->dst.src_port),
801 &ent->dst.ip.dst,
802 ntohs(ent->dst.dst_port),
803 ent->rateinfo.credit, ent->rateinfo.credit_cap,
804 ent->rateinfo.cost);
805 break;
806 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
807 case NFPROTO_IPV6:
808 res = seq_printf(s, "%ld %pI6:%u->%pI6:%u %u %u %u\n",
809 (long)(ent->expires - jiffies)/HZ,
810 &ent->dst.ip6.src,
811 ntohs(ent->dst.src_port),
812 &ent->dst.ip6.dst,
813 ntohs(ent->dst.dst_port),
814 ent->rateinfo.credit, ent->rateinfo.credit_cap,
815 ent->rateinfo.cost);
816 break;
817 #endif
818 default:
819 BUG();
820 res = 0;
821 }
822 spin_unlock(&ent->lock);
823 return res;
824 }
825
826 static int dl_seq_show(struct seq_file *s, void *v)
827 {
828 struct xt_hashlimit_htable *htable = s->private;
829 unsigned int *bucket = (unsigned int *)v;
830 struct dsthash_ent *ent;
831
832 if (!hlist_empty(&htable->hash[*bucket])) {
833 hlist_for_each_entry(ent, &htable->hash[*bucket], node)
834 if (dl_seq_real_show(ent, htable->family, s))
835 return -1;
836 }
837 return 0;
838 }
839
840 static const struct seq_operations dl_seq_ops = {
841 .start = dl_seq_start,
842 .next = dl_seq_next,
843 .stop = dl_seq_stop,
844 .show = dl_seq_show
845 };
846
847 static int dl_proc_open(struct inode *inode, struct file *file)
848 {
849 int ret = seq_open(file, &dl_seq_ops);
850
851 if (!ret) {
852 struct seq_file *sf = file->private_data;
853 sf->private = PDE_DATA(inode);
854 }
855 return ret;
856 }
857
858 static const struct file_operations dl_file_ops = {
859 .owner = THIS_MODULE,
860 .open = dl_proc_open,
861 .read = seq_read,
862 .llseek = seq_lseek,
863 .release = seq_release
864 };
865
866 static int __net_init hashlimit_proc_net_init(struct net *net)
867 {
868 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
869
870 hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
871 if (!hashlimit_net->ipt_hashlimit)
872 return -ENOMEM;
873 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
874 hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
875 if (!hashlimit_net->ip6t_hashlimit) {
876 remove_proc_entry("ipt_hashlimit", net->proc_net);
877 return -ENOMEM;
878 }
879 #endif
880 return 0;
881 }
882
883 static void __net_exit hashlimit_proc_net_exit(struct net *net)
884 {
885 struct xt_hashlimit_htable *hinfo;
886 struct proc_dir_entry *pde;
887 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
888
889 /* recent_net_exit() is called before recent_mt_destroy(). Make sure
890 * that the parent xt_recent proc entry is is empty before trying to
891 * remove it.
892 */
893 mutex_lock(&hashlimit_mutex);
894 pde = hashlimit_net->ipt_hashlimit;
895 if (pde == NULL)
896 pde = hashlimit_net->ip6t_hashlimit;
897
898 hlist_for_each_entry(hinfo, &hashlimit_net->htables, node)
899 remove_proc_entry(hinfo->name, pde);
900
901 hashlimit_net->ipt_hashlimit = NULL;
902 hashlimit_net->ip6t_hashlimit = NULL;
903 mutex_unlock(&hashlimit_mutex);
904
905 remove_proc_entry("ipt_hashlimit", net->proc_net);
906 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
907 remove_proc_entry("ip6t_hashlimit", net->proc_net);
908 #endif
909 }
910
911 static int __net_init hashlimit_net_init(struct net *net)
912 {
913 struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
914
915 INIT_HLIST_HEAD(&hashlimit_net->htables);
916 return hashlimit_proc_net_init(net);
917 }
918
919 static void __net_exit hashlimit_net_exit(struct net *net)
920 {
921 hashlimit_proc_net_exit(net);
922 }
923
924 static struct pernet_operations hashlimit_net_ops = {
925 .init = hashlimit_net_init,
926 .exit = hashlimit_net_exit,
927 .id = &hashlimit_net_id,
928 .size = sizeof(struct hashlimit_net),
929 };
930
931 static int __init hashlimit_mt_init(void)
932 {
933 int err;
934
935 err = register_pernet_subsys(&hashlimit_net_ops);
936 if (err < 0)
937 return err;
938 err = xt_register_matches(hashlimit_mt_reg,
939 ARRAY_SIZE(hashlimit_mt_reg));
940 if (err < 0)
941 goto err1;
942
943 err = -ENOMEM;
944 hashlimit_cachep = kmem_cache_create("xt_hashlimit",
945 sizeof(struct dsthash_ent), 0, 0,
946 NULL);
947 if (!hashlimit_cachep) {
948 pr_warning("unable to create slab cache\n");
949 goto err2;
950 }
951 return 0;
952
953 err2:
954 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
955 err1:
956 unregister_pernet_subsys(&hashlimit_net_ops);
957 return err;
958
959 }
960
961 static void __exit hashlimit_mt_exit(void)
962 {
963 xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
964 unregister_pernet_subsys(&hashlimit_net_ops);
965
966 rcu_barrier_bh();
967 kmem_cache_destroy(hashlimit_cachep);
968 }
969
970 module_init(hashlimit_mt_init);
971 module_exit(hashlimit_mt_exit);
kernel source for telekom puls (alcatel/mediatek)