1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *	xt_hashlimit - Netfilter module to limit the number of packets per time
   4 *	separately for each hashbucket (sourceip/sourceport/dstip/dstport)
   5 *
   6 *	(C) 2003-2004 by Harald Welte <laforge@netfilter.org>
   7 *	(C) 2006-2012 Patrick McHardy <kaber@trash.net>
   8 *	Copyright © CC Computer Consultants GmbH, 2007 - 2008
   9 *
  10 * Development of this code was funded by Astaro AG, http://www.astaro.com/
  11 */
  12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13#include <linux/module.h>
  14#include <linux/spinlock.h>
  15#include <linux/random.h>
  16#include <linux/jhash.h>
  17#include <linux/slab.h>
  18#include <linux/vmalloc.h>
  19#include <linux/proc_fs.h>
  20#include <linux/seq_file.h>
  21#include <linux/list.h>
  22#include <linux/skbuff.h>
  23#include <linux/mm.h>
  24#include <linux/in.h>
  25#include <linux/ip.h>
  26#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  27#include <linux/ipv6.h>
  28#include <net/ipv6.h>
  29#endif
  30
  31#include <net/net_namespace.h>
  32#include <net/netns/generic.h>
  33
  34#include <linux/netfilter/x_tables.h>
  35#include <linux/netfilter_ipv4/ip_tables.h>
  36#include <linux/netfilter_ipv6/ip6_tables.h>
  37#include <linux/mutex.h>
  38#include <linux/kernel.h>
  39#include <linux/refcount.h>
  40#include <uapi/linux/netfilter/xt_hashlimit.h>
  41
  42#define XT_HASHLIMIT_ALL (XT_HASHLIMIT_HASH_DIP | XT_HASHLIMIT_HASH_DPT | \
  43			  XT_HASHLIMIT_HASH_SIP | XT_HASHLIMIT_HASH_SPT | \
  44			  XT_HASHLIMIT_INVERT | XT_HASHLIMIT_BYTES |\
  45			  XT_HASHLIMIT_RATE_MATCH)
  46
  47MODULE_LICENSE("GPL");
  48MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  49MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
  50MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
  51MODULE_ALIAS("ipt_hashlimit");
  52MODULE_ALIAS("ip6t_hashlimit");
  53
  54struct hashlimit_net {
  55	struct hlist_head	htables;
  56	struct proc_dir_entry	*ipt_hashlimit;
  57	struct proc_dir_entry	*ip6t_hashlimit;
  58};
  59
  60static unsigned int hashlimit_net_id;
  61static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
  62{
  63	return net_generic(net, hashlimit_net_id);
  64}
  65
  66/* need to declare this at the top */
  67static const struct seq_operations dl_seq_ops_v2;
  68static const struct seq_operations dl_seq_ops_v1;
  69static const struct seq_operations dl_seq_ops;
  70
  71/* hash table crap */
  72struct dsthash_dst {
  73	union {
  74		struct {
  75			__be32 src;
  76			__be32 dst;
  77		} ip;
  78#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  79		struct {
  80			__be32 src[4];
  81			__be32 dst[4];
  82		} ip6;
  83#endif
  84	};
  85	__be16 src_port;
  86	__be16 dst_port;
  87};
  88
  89struct dsthash_ent {
  90	/* static / read-only parts in the beginning */
  91	struct hlist_node node;
  92	struct dsthash_dst dst;
  93
  94	/* modified structure members in the end */
  95	spinlock_t lock;
  96	unsigned long expires;		/* precalculated expiry time */
  97	struct {
  98		unsigned long prev;	/* last modification */
  99		union {
 100			struct {
 101				u_int64_t credit;
 102				u_int64_t credit_cap;
 103				u_int64_t cost;
 104			};
 105			struct {
 106				u_int32_t interval, prev_window;
 107				u_int64_t current_rate;
 108				u_int64_t rate;
 109				int64_t burst;
 110			};
 111		};
 112	} rateinfo;
 113	struct rcu_head rcu;
 114};
 115
 116struct xt_hashlimit_htable {
 117	struct hlist_node node;		/* global list of all htables */
 118	refcount_t use;
 119	u_int8_t family;
 120	bool rnd_initialized;
 121
 122	struct hashlimit_cfg3 cfg;	/* config */
 123
 124	/* used internally */
 125	spinlock_t lock;		/* lock for list_head */
 126	u_int32_t rnd;			/* random seed for hash */
 127	unsigned int count;		/* number entries in table */
 128	struct delayed_work gc_work;
 129
 130	/* seq_file stuff */
 131	struct proc_dir_entry *pde;
 132	const char *name;
 133	struct net *net;
 134
 135	struct hlist_head hash[];	/* hashtable itself */
 136};
 137
 138static int
 139cfg_copy(struct hashlimit_cfg3 *to, const void *from, int revision)
 140{
 141	if (revision == 1) {
 142		struct hashlimit_cfg1 *cfg = (struct hashlimit_cfg1 *)from;
 143
 144		to->mode = cfg->mode;
 145		to->avg = cfg->avg;
 146		to->burst = cfg->burst;
 147		to->size = cfg->size;
 148		to->max = cfg->max;
 149		to->gc_interval = cfg->gc_interval;
 150		to->expire = cfg->expire;
 151		to->srcmask = cfg->srcmask;
 152		to->dstmask = cfg->dstmask;
 153	} else if (revision == 2) {
 154		struct hashlimit_cfg2 *cfg = (struct hashlimit_cfg2 *)from;
 155
 156		to->mode = cfg->mode;
 157		to->avg = cfg->avg;
 158		to->burst = cfg->burst;
 159		to->size = cfg->size;
 160		to->max = cfg->max;
 161		to->gc_interval = cfg->gc_interval;
 162		to->expire = cfg->expire;
 163		to->srcmask = cfg->srcmask;
 164		to->dstmask = cfg->dstmask;
 165	} else if (revision == 3) {
 166		memcpy(to, from, sizeof(struct hashlimit_cfg3));
 167	} else {
 168		return -EINVAL;
 169	}
 170
 171	return 0;
 172}
 173
 174static DEFINE_MUTEX(hashlimit_mutex);	/* protects htables list */
 175static struct kmem_cache *hashlimit_cachep __read_mostly;
 176
 177static inline bool dst_cmp(const struct dsthash_ent *ent,
 178			   const struct dsthash_dst *b)
 179{
 180	return !memcmp(&ent->dst, b, sizeof(ent->dst));
 181}
 182
 183static u_int32_t
 184hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
 185{
 186	u_int32_t hash = jhash2((const u32 *)dst,
 187				sizeof(*dst)/sizeof(u32),
 188				ht->rnd);
 189	/*
 190	 * Instead of returning hash % ht->cfg.size (implying a divide)
 191	 * we return the high 32 bits of the (hash * ht->cfg.size) that will
 192	 * give results between [0 and cfg.size-1] and same hash distribution,
 193	 * but using a multiply, less expensive than a divide
 194	 */
 195	return reciprocal_scale(hash, ht->cfg.size);
 196}
 197
 198static struct dsthash_ent *
 199dsthash_find(const struct xt_hashlimit_htable *ht,
 200	     const struct dsthash_dst *dst)
 201{
 202	struct dsthash_ent *ent;
 203	u_int32_t hash = hash_dst(ht, dst);
 204
 205	if (!hlist_empty(&ht->hash[hash])) {
 206		hlist_for_each_entry_rcu(ent, &ht->hash[hash], node)
 207			if (dst_cmp(ent, dst)) {
 208				spin_lock(&ent->lock);
 209				return ent;
 210			}
 211	}
 212	return NULL;
 213}
 214
 215/* allocate dsthash_ent, initialize dst, put in htable and lock it */
 216static struct dsthash_ent *
 217dsthash_alloc_init(struct xt_hashlimit_htable *ht,
 218		   const struct dsthash_dst *dst, bool *race)
 219{
 220	struct dsthash_ent *ent;
 221
 222	spin_lock(&ht->lock);
 223
 224	/* Two or more packets may race to create the same entry in the
 225	 * hashtable, double check if this packet lost race.
 226	 */
 227	ent = dsthash_find(ht, dst);
 228	if (ent != NULL) {
 229		spin_unlock(&ht->lock);
 230		*race = true;
 231		return ent;
 232	}
 233
 234	/* initialize hash with random val at the time we allocate
 235	 * the first hashtable entry */
 236	if (unlikely(!ht->rnd_initialized)) {
 237		get_random_bytes(&ht->rnd, sizeof(ht->rnd));
 238		ht->rnd_initialized = true;
 239	}
 240
 241	if (ht->cfg.max && ht->count >= ht->cfg.max) {
 242		/* FIXME: do something. question is what.. */
 243		net_err_ratelimited("max count of %u reached\n", ht->cfg.max);
 244		ent = NULL;
 245	} else
 246		ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
 247	if (ent) {
 248		memcpy(&ent->dst, dst, sizeof(ent->dst));
 249		spin_lock_init(&ent->lock);
 250
 251		spin_lock(&ent->lock);
 252		hlist_add_head_rcu(&ent->node, &ht->hash[hash_dst(ht, dst)]);
 253		ht->count++;
 254	}
 255	spin_unlock(&ht->lock);
 256	return ent;
 257}
 258
 259static void dsthash_free_rcu(struct rcu_head *head)
 260{
 261	struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
 262
 263	kmem_cache_free(hashlimit_cachep, ent);
 264}
 265
 266static inline void
 267dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
 268{
 269	hlist_del_rcu(&ent->node);
 270	call_rcu(&ent->rcu, dsthash_free_rcu);
 271	ht->count--;
 272}
 273static void htable_gc(struct work_struct *work);
 274
 275static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg,
 276			 const char *name, u_int8_t family,
 277			 struct xt_hashlimit_htable **out_hinfo,
 278			 int revision)
 279{
 280	struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
 281	struct xt_hashlimit_htable *hinfo;
 282	const struct seq_operations *ops;
 283	unsigned int size, i;
 284	unsigned long nr_pages = totalram_pages();
 285	int ret;
 286
 287	if (cfg->size) {
 288		size = cfg->size;
 289	} else {
 290		size = (nr_pages << PAGE_SHIFT) / 16384 /
 291		       sizeof(struct hlist_head);
 292		if (nr_pages > 1024 * 1024 * 1024 / PAGE_SIZE)
 293			size = 8192;
 294		if (size < 16)
 295			size = 16;
 296	}
 297	/* FIXME: don't use vmalloc() here or anywhere else -HW */
 298	hinfo = vmalloc(struct_size(hinfo, hash, size));
 299	if (hinfo == NULL)
 300		return -ENOMEM;
 301	*out_hinfo = hinfo;
 302
 303	/* copy match config into hashtable config */
 304	ret = cfg_copy(&hinfo->cfg, (void *)cfg, 3);
 305	if (ret) {
 306		vfree(hinfo);
 307		return ret;
 308	}
 309
 310	hinfo->cfg.size = size;
 311	if (hinfo->cfg.max == 0)
 312		hinfo->cfg.max = 8 * hinfo->cfg.size;
 313	else if (hinfo->cfg.max < hinfo->cfg.size)
 314		hinfo->cfg.max = hinfo->cfg.size;
 315
 316	for (i = 0; i < hinfo->cfg.size; i++)
 317		INIT_HLIST_HEAD(&hinfo->hash[i]);
 318
 319	refcount_set(&hinfo->use, 1);
 320	hinfo->count = 0;
 321	hinfo->family = family;
 322	hinfo->rnd_initialized = false;
 323	hinfo->name = kstrdup(name, GFP_KERNEL);
 324	if (!hinfo->name) {
 325		vfree(hinfo);
 326		return -ENOMEM;
 327	}
 328	spin_lock_init(&hinfo->lock);
 329
 330	switch (revision) {
 331	case 1:
 332		ops = &dl_seq_ops_v1;
 333		break;
 334	case 2:
 335		ops = &dl_seq_ops_v2;
 336		break;
 337	default:
 338		ops = &dl_seq_ops;
 339	}
 340
 341	hinfo->pde = proc_create_seq_data(name, 0,
 342		(family == NFPROTO_IPV4) ?
 343		hashlimit_net->ipt_hashlimit : hashlimit_net->ip6t_hashlimit,
 344		ops, hinfo);
 345	if (hinfo->pde == NULL) {
 346		kfree(hinfo->name);
 347		vfree(hinfo);
 348		return -ENOMEM;
 349	}
 350	hinfo->net = net;
 351
 352	INIT_DEFERRABLE_WORK(&hinfo->gc_work, htable_gc);
 353	queue_delayed_work(system_power_efficient_wq, &hinfo->gc_work,
 354			   msecs_to_jiffies(hinfo->cfg.gc_interval));
 355
 356	hlist_add_head(&hinfo->node, &hashlimit_net->htables);
 357
 358	return 0;
 359}
 360
 361static void htable_selective_cleanup(struct xt_hashlimit_htable *ht, bool select_all)
 362{
 363	unsigned int i;
 364
 365	for (i = 0; i < ht->cfg.size; i++) {
 366		struct dsthash_ent *dh;
 367		struct hlist_node *n;
 368
 369		spin_lock_bh(&ht->lock);
 370		hlist_for_each_entry_safe(dh, n, &ht->hash[i], node) {
 371			if (time_after_eq(jiffies, dh->expires) || select_all)
 372				dsthash_free(ht, dh);
 373		}
 374		spin_unlock_bh(&ht->lock);
 375		cond_resched();
 376	}
 377}
 378
 379static void htable_gc(struct work_struct *work)
 380{
 381	struct xt_hashlimit_htable *ht;
 382
 383	ht = container_of(work, struct xt_hashlimit_htable, gc_work.work);
 384
 385	htable_selective_cleanup(ht, false);
 386
 387	queue_delayed_work(system_power_efficient_wq,
 388			   &ht->gc_work, msecs_to_jiffies(ht->cfg.gc_interval));
 389}
 390
 391static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo)
 392{
 393	struct hashlimit_net *hashlimit_net = hashlimit_pernet(hinfo->net);
 394	struct proc_dir_entry *parent;
 395
 396	if (hinfo->family == NFPROTO_IPV4)
 397		parent = hashlimit_net->ipt_hashlimit;
 398	else
 399		parent = hashlimit_net->ip6t_hashlimit;
 400
 401	if (parent != NULL)
 402		remove_proc_entry(hinfo->name, parent);
 403}
 404
 405static struct xt_hashlimit_htable *htable_find_get(struct net *net,
 406						   const char *name,
 407						   u_int8_t family)
 408{
 409	struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
 410	struct xt_hashlimit_htable *hinfo;
 411
 412	hlist_for_each_entry(hinfo, &hashlimit_net->htables, node) {
 413		if (!strcmp(name, hinfo->name) &&
 414		    hinfo->family == family) {
 415			refcount_inc(&hinfo->use);
 416			return hinfo;
 417		}
 418	}
 419	return NULL;
 420}
 421
 422static void htable_put(struct xt_hashlimit_htable *hinfo)
 423{
 424	if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) {
 425		hlist_del(&hinfo->node);
 426		htable_remove_proc_entry(hinfo);
 427		mutex_unlock(&hashlimit_mutex);
 428
 429		cancel_delayed_work_sync(&hinfo->gc_work);
 430		htable_selective_cleanup(hinfo, true);
 431		kfree(hinfo->name);
 432		vfree(hinfo);
 433	}
 434}
 435
 436/* The algorithm used is the Simple Token Bucket Filter (TBF)
 437 * see net/sched/sch_tbf.c in the linux source tree
 438 */
 439
 440/* Rusty: This is my (non-mathematically-inclined) understanding of
 441   this algorithm.  The `average rate' in jiffies becomes your initial
 442   amount of credit `credit' and the most credit you can ever have
 443   `credit_cap'.  The `peak rate' becomes the cost of passing the
 444   test, `cost'.
 445
 446   `prev' tracks the last packet hit: you gain one credit per jiffy.
 447   If you get credit balance more than this, the extra credit is
 448   discarded.  Every time the match passes, you lose `cost' credits;
 449   if you don't have that many, the test fails.
 450
 451   See Alexey's formal explanation in net/sched/sch_tbf.c.
 452
 453   To get the maximum range, we multiply by this factor (ie. you get N
 454   credits per jiffy).  We want to allow a rate as low as 1 per day
 455   (slowest userspace tool allows), which means
 456   CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
 457*/
 458#define MAX_CPJ_v1 (0xFFFFFFFF / (HZ*60*60*24))
 459#define MAX_CPJ (0xFFFFFFFFFFFFFFFFULL / (HZ*60*60*24))
 460
 461/* Repeated shift and or gives us all 1s, final shift and add 1 gives
 462 * us the power of 2 below the theoretical max, so GCC simply does a
 463 * shift. */
 464#define _POW2_BELOW2(x) ((x)|((x)>>1))
 465#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
 466#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
 467#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
 468#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
 469#define _POW2_BELOW64(x) (_POW2_BELOW32(x)|_POW2_BELOW32((x)>>32))
 470#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
 471#define POW2_BELOW64(x) ((_POW2_BELOW64(x)>>1) + 1)
 472
 473#define CREDITS_PER_JIFFY POW2_BELOW64(MAX_CPJ)
 474#define CREDITS_PER_JIFFY_v1 POW2_BELOW32(MAX_CPJ_v1)
 475
 476/* in byte mode, the lowest possible rate is one packet/second.
 477 * credit_cap is used as a counter that tells us how many times we can
 478 * refill the "credits available" counter when it becomes empty.
 479 */
 480#define MAX_CPJ_BYTES (0xFFFFFFFF / HZ)
 481#define CREDITS_PER_JIFFY_BYTES POW2_BELOW32(MAX_CPJ_BYTES)
 482
 483static u32 xt_hashlimit_len_to_chunks(u32 len)
 484{
 485	return (len >> XT_HASHLIMIT_BYTE_SHIFT) + 1;
 486}
 487
 488/* Precision saver. */
 489static u64 user2credits(u64 user, int revision)
 490{
 491	u64 scale = (revision == 1) ?
 492		XT_HASHLIMIT_SCALE : XT_HASHLIMIT_SCALE_v2;
 493	u64 cpj = (revision == 1) ?
 494		CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
 495
 496	/* Avoid overflow: divide the constant operands first */
 497	if (scale >= HZ * cpj)
 498		return div64_u64(user, div64_u64(scale, HZ * cpj));
 499
 500	return user * div64_u64(HZ * cpj, scale);
 501}
 502
 503static u32 user2credits_byte(u32 user)
 504{
 505	u64 us = user;
 506	us *= HZ * CREDITS_PER_JIFFY_BYTES;
 507	return (u32) (us >> 32);
 508}
 509
 510static u64 user2rate(u64 user)
 511{
 512	if (user != 0) {
 513		return div64_u64(XT_HASHLIMIT_SCALE_v2, user);
 514	} else {
 515		pr_info_ratelimited("invalid rate from userspace: %llu\n",
 516				    user);
 517		return 0;
 518	}
 519}
 520
 521static u64 user2rate_bytes(u32 user)
 522{
 523	u64 r;
 524
 525	r = user ? U32_MAX / user : U32_MAX;
 526	return (r - 1) << XT_HASHLIMIT_BYTE_SHIFT;
 527}
 528
 529static void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now,
 530			    u32 mode, int revision)
 531{
 532	unsigned long delta = now - dh->rateinfo.prev;
 533	u64 cap, cpj;
 534
 535	if (delta == 0)
 536		return;
 537
 538	if (revision >= 3 && mode & XT_HASHLIMIT_RATE_MATCH) {
 539		u64 interval = dh->rateinfo.interval * HZ;
 540
 541		if (delta < interval)
 542			return;
 543
 544		dh->rateinfo.prev = now;
 545		dh->rateinfo.prev_window =
 546			((dh->rateinfo.current_rate * interval) >
 547			 (delta * dh->rateinfo.rate));
 548		dh->rateinfo.current_rate = 0;
 549
 550		return;
 551	}
 552
 553	dh->rateinfo.prev = now;
 554
 555	if (mode & XT_HASHLIMIT_BYTES) {
 556		u64 tmp = dh->rateinfo.credit;
 557		dh->rateinfo.credit += CREDITS_PER_JIFFY_BYTES * delta;
 558		cap = CREDITS_PER_JIFFY_BYTES * HZ;
 559		if (tmp >= dh->rateinfo.credit) {/* overflow */
 560			dh->rateinfo.credit = cap;
 561			return;
 562		}
 563	} else {
 564		cpj = (revision == 1) ?
 565			CREDITS_PER_JIFFY_v1 : CREDITS_PER_JIFFY;
 566		dh->rateinfo.credit += delta * cpj;
 567		cap = dh->rateinfo.credit_cap;
 568	}
 569	if (dh->rateinfo.credit > cap)
 570		dh->rateinfo.credit = cap;
 571}
 572
 573static void rateinfo_init(struct dsthash_ent *dh,
 574			  struct xt_hashlimit_htable *hinfo, int revision)
 575{
 576	dh->rateinfo.prev = jiffies;
 577	if (revision >= 3 && hinfo->cfg.mode & XT_HASHLIMIT_RATE_MATCH) {
 578		dh->rateinfo.prev_window = 0;
 579		dh->rateinfo.current_rate = 0;
 580		if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
 581			dh->rateinfo.rate =
 582				user2rate_bytes((u32)hinfo->cfg.avg);
 583			if (hinfo->cfg.burst)
 584				dh->rateinfo.burst =
 585					hinfo->cfg.burst * dh->rateinfo.rate;
 586			else
 587				dh->rateinfo.burst = dh->rateinfo.rate;
 588		} else {
 589			dh->rateinfo.rate = user2rate(hinfo->cfg.avg);
 590			dh->rateinfo.burst =
 591				hinfo->cfg.burst + dh->rateinfo.rate;
 592		}
 593		dh->rateinfo.interval = hinfo->cfg.interval;
 594	} else if (hinfo->cfg.mode & XT_HASHLIMIT_BYTES) {
 595		dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
 596		dh->rateinfo.cost = user2credits_byte(hinfo->cfg.avg);
 597		dh->rateinfo.credit_cap = hinfo->cfg.burst;
 598	} else {
 599		dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
 600						   hinfo->cfg.burst, revision);
 601		dh->rateinfo.cost = user2credits(hinfo->cfg.avg, revision);
 602		dh->rateinfo.credit_cap = dh->rateinfo.credit;
 603	}
 604}
 605
 606static inline __be32 maskl(__be32 a, unsigned int l)
 607{
 608	return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
 609}
 610
 611#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 612static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
 613{
 614	switch (p) {
 615	case 0 ... 31:
 616		i[0] = maskl(i[0], p);
 617		i[1] = i[2] = i[3] = 0;
 618		break;
 619	case 32 ... 63:
 620		i[1] = maskl(i[1], p - 32);
 621		i[2] = i[3] = 0;
 622		break;
 623	case 64 ... 95:
 624		i[2] = maskl(i[2], p - 64);
 625		i[3] = 0;
 626		break;
 627	case 96 ... 127:
 628		i[3] = maskl(i[3], p - 96);
 629		break;
 630	case 128:
 631		break;
 632	}
 633}
 634#endif
 635
 636static int
 637hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
 638		   struct dsthash_dst *dst,
 639		   const struct sk_buff *skb, unsigned int protoff)
 640{
 641	__be16 _ports[2], *ports;
 642	u8 nexthdr;
 643	int poff;
 644
 645	memset(dst, 0, sizeof(*dst));
 646
 647	switch (hinfo->family) {
 648	case NFPROTO_IPV4:
 649		if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
 650			dst->ip.dst = maskl(ip_hdr(skb)->daddr,
 651			              hinfo->cfg.dstmask);
 652		if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
 653			dst->ip.src = maskl(ip_hdr(skb)->saddr,
 654			              hinfo->cfg.srcmask);
 655
 656		if (!(hinfo->cfg.mode &
 657		      (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
 658			return 0;
 659		nexthdr = ip_hdr(skb)->protocol;
 660		break;
 661#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
 662	case NFPROTO_IPV6:
 663	{
 664		__be16 frag_off;
 665
 666		if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
 667			memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
 668			       sizeof(dst->ip6.dst));
 669			hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
 670		}
 671		if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
 672			memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
 673			       sizeof(dst->ip6.src));
 674			hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
 675		}
 676
 677		if (!(hinfo->cfg.mode &
 678		      (XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
 679			return 0;
 680		nexthdr = ipv6_hdr(skb)->nexthdr;
 681		protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr, &frag_off);
 682		if ((int)protoff < 0)
 683			return -1;
 684		break;
 685	}
 686#endif
 687	default:
 688		BUG();
 689		return 0;
 690	}
 691
 692	poff = proto_ports_offset(nexthdr);
 693	if (poff >= 0) {
 694		ports = skb_header_pointer(skb, protoff + poff, sizeof(_ports),
 695					   &_ports);
 696	} else {
 697		_ports[0] = _ports[1] = 0;
 698		ports = _ports;
 699	}
 700	if (!ports)
 701		return -1;
 702	if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
 703		dst->src_port = ports[0];
 704	if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
 705		dst->dst_port = ports[1];
 706	return 0;
 707}
 708
 709static u32 hashlimit_byte_cost(unsigned int len, struct dsthash_ent *dh)
 710{
 711	u64 tmp = xt_hashlimit_len_to_chunks(len);
 712	tmp = tmp * dh->rateinfo.cost;
 713
 714	if (unlikely(tmp > CREDITS_PER_JIFFY_BYTES * HZ))
 715		tmp = CREDITS_PER_JIFFY_BYTES * HZ;
 716
 717	if (dh->rateinfo.credit < tmp && dh->rateinfo.credit_cap) {
 718		dh->rateinfo.credit_cap--;
 719		dh->rateinfo.credit = CREDITS_PER_JIFFY_BYTES * HZ;
 720	}
 721	return (u32) tmp;
 722}
 723
 724static bool
 725hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
 726		    struct xt_hashlimit_htable *hinfo,
 727		    const struct hashlimit_cfg3 *cfg, int revision)
 728{
 729	unsigned long now = jiffies;
 730	struct dsthash_ent *dh;
 731	struct dsthash_dst dst;
 732	bool race = false;
 733	u64 cost;
 734
 735	if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
 736		goto hotdrop;
 737
 738	local_bh_disable();
 739	dh = dsthash_find(hinfo, &dst);
 740	if (dh == NULL) {
 741		dh = dsthash_alloc_init(hinfo, &dst, &race);
 742		if (dh == NULL) {
 743			local_bh_enable();
 744			goto hotdrop;
 745		} else if (race) {
 746			/* Already got an entry, update expiration timeout */
 747			dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
 748			rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
 749		} else {
 750			dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
 751			rateinfo_init(dh, hinfo, revision);
 752		}
 753	} else {
 754		/* update expiration timeout */
 755		dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
 756		rateinfo_recalc(dh, now, hinfo->cfg.mode, revision);
 757	}
 758
 759	if (cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
 760		cost = (cfg->mode & XT_HASHLIMIT_BYTES) ? skb->len : 1;
 761		dh->rateinfo.current_rate += cost;
 762
 763		if (!dh->rateinfo.prev_window &&
 764		    (dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
 765			spin_unlock(&dh->lock);
 766			local_bh_enable();
 767			return !(cfg->mode & XT_HASHLIMIT_INVERT);
 768		} else {
 769			goto overlimit;
 770		}
 771	}
 772
 773	if (cfg->mode & XT_HASHLIMIT_BYTES)
 774		cost = hashlimit_byte_cost(skb->len, dh);
 775	else
 776		cost = dh->rateinfo.cost;
 777
 778	if (dh->rateinfo.credit >= cost) {
 779		/* below the limit */
 780		dh->rateinfo.credit -= cost;
 781		spin_unlock(&dh->lock);
 782		local_bh_enable();
 783		return !(cfg->mode & XT_HASHLIMIT_INVERT);
 784	}
 785
 786overlimit:
 787	spin_unlock(&dh->lock);
 788	local_bh_enable();
 789	/* default match is underlimit - so over the limit, we need to invert */
 790	return cfg->mode & XT_HASHLIMIT_INVERT;
 791
 792 hotdrop:
 793	par->hotdrop = true;
 794	return false;
 795}
 796
 797static bool
 798hashlimit_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
 799{
 800	const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
 801	struct xt_hashlimit_htable *hinfo = info->hinfo;
 802	struct hashlimit_cfg3 cfg = {};
 803	int ret;
 804
 805	ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
 806	if (ret)
 807		return ret;
 808
 809	return hashlimit_mt_common(skb, par, hinfo, &cfg, 1);
 810}
 811
 812static bool
 813hashlimit_mt_v2(const struct sk_buff *skb, struct xt_action_param *par)
 814{
 815	const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
 816	struct xt_hashlimit_htable *hinfo = info->hinfo;
 817	struct hashlimit_cfg3 cfg = {};
 818	int ret;
 819
 820	ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
 821	if (ret)
 822		return ret;
 823
 824	return hashlimit_mt_common(skb, par, hinfo, &cfg, 2);
 825}
 826
 827static bool
 828hashlimit_mt(const struct sk_buff *skb, struct xt_action_param *par)
 829{
 830	const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
 831	struct xt_hashlimit_htable *hinfo = info->hinfo;
 832
 833	return hashlimit_mt_common(skb, par, hinfo, &info->cfg, 3);
 834}
 835
 836#define HASHLIMIT_MAX_SIZE 1048576
 837
 838static int hashlimit_mt_check_common(const struct xt_mtchk_param *par,
 839				     struct xt_hashlimit_htable **hinfo,
 840				     struct hashlimit_cfg3 *cfg,
 841				     const char *name, int revision)
 842{
 843	struct net *net = par->net;
 844	int ret;
 845
 846	if (cfg->gc_interval == 0 || cfg->expire == 0)
 847		return -EINVAL;
 848	if (cfg->size > HASHLIMIT_MAX_SIZE) {
 849		cfg->size = HASHLIMIT_MAX_SIZE;
 850		pr_info_ratelimited("size too large, truncated to %u\n", cfg->size);
 851	}
 852	if (cfg->max > HASHLIMIT_MAX_SIZE) {
 853		cfg->max = HASHLIMIT_MAX_SIZE;
 854		pr_info_ratelimited("max too large, truncated to %u\n", cfg->max);
 855	}
 856	if (par->family == NFPROTO_IPV4) {
 857		if (cfg->srcmask > 32 || cfg->dstmask > 32)
 858			return -EINVAL;
 859	} else {
 860		if (cfg->srcmask > 128 || cfg->dstmask > 128)
 861			return -EINVAL;
 862	}
 863
 864	if (cfg->mode & ~XT_HASHLIMIT_ALL) {
 865		pr_info_ratelimited("Unknown mode mask %X, kernel too old?\n",
 866				    cfg->mode);
 867		return -EINVAL;
 868	}
 869
 870	/* Check for overflow. */
 871	if (revision >= 3 && cfg->mode & XT_HASHLIMIT_RATE_MATCH) {
 872		if (cfg->avg == 0 || cfg->avg > U32_MAX) {
 873			pr_info_ratelimited("invalid rate\n");
 874			return -ERANGE;
 875		}
 876
 877		if (cfg->interval == 0) {
 878			pr_info_ratelimited("invalid interval\n");
 879			return -EINVAL;
 880		}
 881	} else if (cfg->mode & XT_HASHLIMIT_BYTES) {
 882		if (user2credits_byte(cfg->avg) == 0) {
 883			pr_info_ratelimited("overflow, rate too high: %llu\n",
 884					    cfg->avg);
 885			return -EINVAL;
 886		}
 887	} else if (cfg->burst == 0 ||
 888		   user2credits(cfg->avg * cfg->burst, revision) <
 889		   user2credits(cfg->avg, revision)) {
 890		pr_info_ratelimited("overflow, try lower: %llu/%llu\n",
 891				    cfg->avg, cfg->burst);
 892		return -ERANGE;
 893	}
 894
 895	mutex_lock(&hashlimit_mutex);
 896	*hinfo = htable_find_get(net, name, par->family);
 897	if (*hinfo == NULL) {
 898		ret = htable_create(net, cfg, name, par->family,
 899				    hinfo, revision);
 900		if (ret < 0) {
 901			mutex_unlock(&hashlimit_mutex);
 902			return ret;
 903		}
 904	}
 905	mutex_unlock(&hashlimit_mutex);
 906
 907	return 0;
 908}
 909
 910static int hashlimit_mt_check_v1(const struct xt_mtchk_param *par)
 911{
 912	struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
 913	struct hashlimit_cfg3 cfg = {};
 914	int ret;
 915
 916	ret = xt_check_proc_name(info->name, sizeof(info->name));
 917	if (ret)
 918		return ret;
 919
 920	ret = cfg_copy(&cfg, (void *)&info->cfg, 1);
 921	if (ret)
 922		return ret;
 923
 924	return hashlimit_mt_check_common(par, &info->hinfo,
 925					 &cfg, info->name, 1);
 926}
 927
 928static int hashlimit_mt_check_v2(const struct xt_mtchk_param *par)
 929{
 930	struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
 931	struct hashlimit_cfg3 cfg = {};
 932	int ret;
 933
 934	ret = xt_check_proc_name(info->name, sizeof(info->name));
 935	if (ret)
 936		return ret;
 937
 938	ret = cfg_copy(&cfg, (void *)&info->cfg, 2);
 939	if (ret)
 940		return ret;
 941
 942	return hashlimit_mt_check_common(par, &info->hinfo,
 943					 &cfg, info->name, 2);
 944}
 945
 946static int hashlimit_mt_check(const struct xt_mtchk_param *par)
 947{
 948	struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
 949	int ret;
 950
 951	ret = xt_check_proc_name(info->name, sizeof(info->name));
 952	if (ret)
 953		return ret;
 954
 955	return hashlimit_mt_check_common(par, &info->hinfo, &info->cfg,
 956					 info->name, 3);
 957}
 958
 959static void hashlimit_mt_destroy_v2(const struct xt_mtdtor_param *par)
 960{
 961	const struct xt_hashlimit_mtinfo2 *info = par->matchinfo;
 962
 963	htable_put(info->hinfo);
 964}
 965
 966static void hashlimit_mt_destroy_v1(const struct xt_mtdtor_param *par)
 967{
 968	const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
 969
 970	htable_put(info->hinfo);
 971}
 972
 973static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
 974{
 975	const struct xt_hashlimit_mtinfo3 *info = par->matchinfo;
 976
 977	htable_put(info->hinfo);
 978}
 979
 980static struct xt_match hashlimit_mt_reg[] __read_mostly = {
 981	{
 982		.name           = "hashlimit",
 983		.revision       = 1,
 984		.family         = NFPROTO_IPV4,
 985		.match          = hashlimit_mt_v1,
 986		.matchsize      = sizeof(struct xt_hashlimit_mtinfo1),
 987		.usersize	= offsetof(struct xt_hashlimit_mtinfo1, hinfo),
 988		.checkentry     = hashlimit_mt_check_v1,
 989		.destroy        = hashlimit_mt_destroy_v1,
 990		.me             = THIS_MODULE,
 991	},
 992	{
 993		.name           = "hashlimit",
 994		.revision       = 2,
 995		.family         = NFPROTO_IPV4,
 996		.match          = hashlimit_mt_v2,
 997		.matchsize      = sizeof(struct xt_hashlimit_mtinfo2),
 998		.usersize	= offsetof(struct xt_hashlimit_mtinfo2, hinfo),
 999		.checkentry     = hashlimit_mt_check_v2,
1000		.destroy        = hashlimit_mt_destroy_v2,
1001		.me             = THIS_MODULE,
1002	},
1003	{
1004		.name           = "hashlimit",
1005		.revision       = 3,
1006		.family         = NFPROTO_IPV4,
1007		.match          = hashlimit_mt,
1008		.matchsize      = sizeof(struct xt_hashlimit_mtinfo3),
1009		.usersize	= offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1010		.checkentry     = hashlimit_mt_check,
1011		.destroy        = hashlimit_mt_destroy,
1012		.me             = THIS_MODULE,
1013	},
1014#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1015	{
1016		.name           = "hashlimit",
1017		.revision       = 1,
1018		.family         = NFPROTO_IPV6,
1019		.match          = hashlimit_mt_v1,
1020		.matchsize      = sizeof(struct xt_hashlimit_mtinfo1),
1021		.usersize	= offsetof(struct xt_hashlimit_mtinfo1, hinfo),
1022		.checkentry     = hashlimit_mt_check_v1,
1023		.destroy        = hashlimit_mt_destroy_v1,
1024		.me             = THIS_MODULE,
1025	},
1026	{
1027		.name           = "hashlimit",
1028		.revision       = 2,
1029		.family         = NFPROTO_IPV6,
1030		.match          = hashlimit_mt_v2,
1031		.matchsize      = sizeof(struct xt_hashlimit_mtinfo2),
1032		.usersize	= offsetof(struct xt_hashlimit_mtinfo2, hinfo),
1033		.checkentry     = hashlimit_mt_check_v2,
1034		.destroy        = hashlimit_mt_destroy_v2,
1035		.me             = THIS_MODULE,
1036	},
1037	{
1038		.name           = "hashlimit",
1039		.revision       = 3,
1040		.family         = NFPROTO_IPV6,
1041		.match          = hashlimit_mt,
1042		.matchsize      = sizeof(struct xt_hashlimit_mtinfo3),
1043		.usersize	= offsetof(struct xt_hashlimit_mtinfo3, hinfo),
1044		.checkentry     = hashlimit_mt_check,
1045		.destroy        = hashlimit_mt_destroy,
1046		.me             = THIS_MODULE,
1047	},
1048#endif
1049};
1050
1051/* PROC stuff */
1052static void *dl_seq_start(struct seq_file *s, loff_t *pos)
1053	__acquires(htable->lock)
1054{
1055	struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1056	unsigned int *bucket;
1057
1058	spin_lock_bh(&htable->lock);
1059	if (*pos >= htable->cfg.size)
1060		return NULL;
1061
1062	bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
1063	if (!bucket)
1064		return ERR_PTR(-ENOMEM);
1065
1066	*bucket = *pos;
1067	return bucket;
1068}
1069
1070static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
1071{
1072	struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1073	unsigned int *bucket = v;
1074
1075	*pos = ++(*bucket);
1076	if (*pos >= htable->cfg.size) {
1077		kfree(v);
1078		return NULL;
1079	}
1080	return bucket;
1081}
1082
1083static void dl_seq_stop(struct seq_file *s, void *v)
1084	__releases(htable->lock)
1085{
1086	struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1087	unsigned int *bucket = v;
1088
1089	if (!IS_ERR(bucket))
1090		kfree(bucket);
1091	spin_unlock_bh(&htable->lock);
1092}
1093
1094static void dl_seq_print(struct dsthash_ent *ent, u_int8_t family,
1095			 struct seq_file *s)
1096{
1097	switch (family) {
1098	case NFPROTO_IPV4:
1099		seq_printf(s, "%ld %pI4:%u->%pI4:%u %llu %llu %llu\n",
1100			   (long)(ent->expires - jiffies)/HZ,
1101			   &ent->dst.ip.src,
1102			   ntohs(ent->dst.src_port),
1103			   &ent->dst.ip.dst,
1104			   ntohs(ent->dst.dst_port),
1105			   ent->rateinfo.credit, ent->rateinfo.credit_cap,
1106			   ent->rateinfo.cost);
1107		break;
1108#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1109	case NFPROTO_IPV6:
1110		seq_printf(s, "%ld %pI6:%u->%pI6:%u %llu %llu %llu\n",
1111			   (long)(ent->expires - jiffies)/HZ,
1112			   &ent->dst.ip6.src,
1113			   ntohs(ent->dst.src_port),
1114			   &ent->dst.ip6.dst,
1115			   ntohs(ent->dst.dst_port),
1116			   ent->rateinfo.credit, ent->rateinfo.credit_cap,
1117			   ent->rateinfo.cost);
1118		break;
1119#endif
1120	default:
1121		BUG();
1122	}
1123}
1124
1125static int dl_seq_real_show_v2(struct dsthash_ent *ent, u_int8_t family,
1126			       struct seq_file *s)
1127{
1128	struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1129
1130	spin_lock(&ent->lock);
1131	/* recalculate to show accurate numbers */
1132	rateinfo_recalc(ent, jiffies, ht->cfg.mode, 2);
1133
1134	dl_seq_print(ent, family, s);
1135
1136	spin_unlock(&ent->lock);
1137	return seq_has_overflowed(s);
1138}
1139
1140static int dl_seq_real_show_v1(struct dsthash_ent *ent, u_int8_t family,
1141			       struct seq_file *s)
1142{
1143	struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1144
1145	spin_lock(&ent->lock);
1146	/* recalculate to show accurate numbers */
1147	rateinfo_recalc(ent, jiffies, ht->cfg.mode, 1);
1148
1149	dl_seq_print(ent, family, s);
1150
1151	spin_unlock(&ent->lock);
1152	return seq_has_overflowed(s);
1153}
1154
1155static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
1156			    struct seq_file *s)
1157{
1158	struct xt_hashlimit_htable *ht = PDE_DATA(file_inode(s->file));
1159
1160	spin_lock(&ent->lock);
1161	/* recalculate to show accurate numbers */
1162	rateinfo_recalc(ent, jiffies, ht->cfg.mode, 3);
1163
1164	dl_seq_print(ent, family, s);
1165
1166	spin_unlock(&ent->lock);
1167	return seq_has_overflowed(s);
1168}
1169
1170static int dl_seq_show_v2(struct seq_file *s, void *v)
1171{
1172	struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1173	unsigned int *bucket = (unsigned int *)v;
1174	struct dsthash_ent *ent;
1175
1176	if (!hlist_empty(&htable->hash[*bucket])) {
1177		hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1178			if (dl_seq_real_show_v2(ent, htable->family, s))
1179				return -1;
1180	}
1181	return 0;
1182}
1183
1184static int dl_seq_show_v1(struct seq_file *s, void *v)
1185{
1186	struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1187	unsigned int *bucket = v;
1188	struct dsthash_ent *ent;
1189
1190	if (!hlist_empty(&htable->hash[*bucket])) {
1191		hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1192			if (dl_seq_real_show_v1(ent, htable->family, s))
1193				return -1;
1194	}
1195	return 0;
1196}
1197
1198static int dl_seq_show(struct seq_file *s, void *v)
1199{
1200	struct xt_hashlimit_htable *htable = PDE_DATA(file_inode(s->file));
1201	unsigned int *bucket = v;
1202	struct dsthash_ent *ent;
1203
1204	if (!hlist_empty(&htable->hash[*bucket])) {
1205		hlist_for_each_entry(ent, &htable->hash[*bucket], node)
1206			if (dl_seq_real_show(ent, htable->family, s))
1207				return -1;
1208	}
1209	return 0;
1210}
1211
1212static const struct seq_operations dl_seq_ops_v1 = {
1213	.start = dl_seq_start,
1214	.next  = dl_seq_next,
1215	.stop  = dl_seq_stop,
1216	.show  = dl_seq_show_v1
1217};
1218
1219static const struct seq_operations dl_seq_ops_v2 = {
1220	.start = dl_seq_start,
1221	.next  = dl_seq_next,
1222	.stop  = dl_seq_stop,
1223	.show  = dl_seq_show_v2
1224};
1225
1226static const struct seq_operations dl_seq_ops = {
1227	.start = dl_seq_start,
1228	.next  = dl_seq_next,
1229	.stop  = dl_seq_stop,
1230	.show  = dl_seq_show
1231};
1232
1233static int __net_init hashlimit_proc_net_init(struct net *net)
1234{
1235	struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1236
1237	hashlimit_net->ipt_hashlimit = proc_mkdir("ipt_hashlimit", net->proc_net);
1238	if (!hashlimit_net->ipt_hashlimit)
1239		return -ENOMEM;
1240#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1241	hashlimit_net->ip6t_hashlimit = proc_mkdir("ip6t_hashlimit", net->proc_net);
1242	if (!hashlimit_net->ip6t_hashlimit) {
1243		remove_proc_entry("ipt_hashlimit", net->proc_net);
1244		return -ENOMEM;
1245	}
1246#endif
1247	return 0;
1248}
1249
1250static void __net_exit hashlimit_proc_net_exit(struct net *net)
1251{
1252	struct xt_hashlimit_htable *hinfo;
1253	struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1254
1255	/* hashlimit_net_exit() is called before hashlimit_mt_destroy().
1256	 * Make sure that the parent ipt_hashlimit and ip6t_hashlimit proc
1257	 * entries is empty before trying to remove it.
1258	 */
1259	mutex_lock(&hashlimit_mutex);
1260	hlist_for_each_entry(hinfo, &hashlimit_net->htables, node)
1261		htable_remove_proc_entry(hinfo);
1262	hashlimit_net->ipt_hashlimit = NULL;
1263	hashlimit_net->ip6t_hashlimit = NULL;
1264	mutex_unlock(&hashlimit_mutex);
1265
1266	remove_proc_entry("ipt_hashlimit", net->proc_net);
1267#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
1268	remove_proc_entry("ip6t_hashlimit", net->proc_net);
1269#endif
1270}
1271
1272static int __net_init hashlimit_net_init(struct net *net)
1273{
1274	struct hashlimit_net *hashlimit_net = hashlimit_pernet(net);
1275
1276	INIT_HLIST_HEAD(&hashlimit_net->htables);
1277	return hashlimit_proc_net_init(net);
1278}
1279
1280static void __net_exit hashlimit_net_exit(struct net *net)
1281{
1282	hashlimit_proc_net_exit(net);
1283}
1284
1285static struct pernet_operations hashlimit_net_ops = {
1286	.init	= hashlimit_net_init,
1287	.exit	= hashlimit_net_exit,
1288	.id	= &hashlimit_net_id,
1289	.size	= sizeof(struct hashlimit_net),
1290};
1291
1292static int __init hashlimit_mt_init(void)
1293{
1294	int err;
1295
1296	err = register_pernet_subsys(&hashlimit_net_ops);
1297	if (err < 0)
1298		return err;
1299	err = xt_register_matches(hashlimit_mt_reg,
1300	      ARRAY_SIZE(hashlimit_mt_reg));
1301	if (err < 0)
1302		goto err1;
1303
1304	err = -ENOMEM;
1305	hashlimit_cachep = kmem_cache_create("xt_hashlimit",
1306					    sizeof(struct dsthash_ent), 0, 0,
1307					    NULL);
1308	if (!hashlimit_cachep) {
1309		pr_warn("unable to create slab cache\n");
1310		goto err2;
1311	}
1312	return 0;
1313
1314err2:
1315	xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1316err1:
1317	unregister_pernet_subsys(&hashlimit_net_ops);
1318	return err;
1319
1320}
1321
1322static void __exit hashlimit_mt_exit(void)
1323{
1324	xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
1325	unregister_pernet_subsys(&hashlimit_net_ops);
1326
1327	rcu_barrier();
1328	kmem_cache_destroy(hashlimit_cachep);
1329}
1330
1331module_init(hashlimit_mt_init);
1332module_exit(hashlimit_mt_exit);