[mirror_ubuntu-bionic-kernel.git] / net / ipv4 / inet_fragment.c

/*
 * inet fragments management
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 * 		Authors:	Pavel Emelyanov <xemul@openvz.org>
 *				Started as consolidation of ipv4/ip_fragment.c,
 *				ipv6/reassembly. and ipv6 nf conntrack reassembly
 */

#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/slab.h>

#include <net/sock.h>
#include <net/inet_frag.h>
#include <net/inet_ecn.h>

#define INETFRAGS_EVICT_BUCKETS   128
#define INETFRAGS_EVICT_MAX	  512

/* don't rebuild inetfrag table with new secret more often than this */
#define INETFRAGS_MIN_REBUILD_INTERVAL (5 * HZ)

/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
 * Value : 0xff if frame should be dropped.
 *         0 or INET_ECN_CE value, to be ORed in to final iph->tos field
 */
const u8 ip_frag_ecn_table[16] = {
	/* at least one fragment had CE, and others ECT_0 or ECT_1 */
	[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0]			= INET_ECN_CE,
	[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1]			= INET_ECN_CE,
	[IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1]	= INET_ECN_CE,

	/* invalid combinations : drop frame */
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
	[IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
};
EXPORT_SYMBOL(ip_frag_ecn_table);

static unsigned int
inet_frag_hashfn(const struct inet_frags *f, const struct inet_frag_queue *q)
{
	return f->hashfn(q) & (INETFRAGS_HASHSZ - 1);
}

static bool inet_frag_may_rebuild(struct inet_frags *f)
{
	return time_after(jiffies,
	       f->last_rebuild_jiffies + INETFRAGS_MIN_REBUILD_INTERVAL);
}

static void inet_frag_secret_rebuild(struct inet_frags *f)
{
	int i;

	write_seqlock_bh(&f->rnd_seqlock);

	if (!inet_frag_may_rebuild(f))
		goto out;

	get_random_bytes(&f->rnd, sizeof(u32));

	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
		struct inet_frag_bucket *hb;
		struct inet_frag_queue *q;
		struct hlist_node *n;

		hb = &f->hash[i];
		spin_lock(&hb->chain_lock);

		hlist_for_each_entry_safe(q, n, &hb->chain, list) {
			unsigned int hval = inet_frag_hashfn(f, q);

			if (hval != i) {
				struct inet_frag_bucket *hb_dest;

				hlist_del(&q->list);

				/* Relink to new hash chain. */
				hb_dest = &f->hash[hval];

				/* This is the only place where we take
				 * another chain_lock while already holding
				 * one.  As this will not run concurrently,
				 * we cannot deadlock on hb_dest lock below, if its
				 * already locked it will be released soon since
				 * other caller cannot be waiting for hb lock
				 * that we've taken above.
				 */
				spin_lock_nested(&hb_dest->chain_lock,
						 SINGLE_DEPTH_NESTING);
				hlist_add_head(&q->list, &hb_dest->chain);
				spin_unlock(&hb_dest->chain_lock);
			}
		}
		spin_unlock(&hb->chain_lock);
	}

	f->rebuild = false;
	f->last_rebuild_jiffies = jiffies;
out:
	write_sequnlock_bh(&f->rnd_seqlock);
}

static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
{
	if (!hlist_unhashed(&q->list_evictor))
		return false;

	return q->net->low_thresh == 0 ||
	       frag_mem_limit(q->net) >= q->net->low_thresh;
}

static unsigned int
inet_evict_bucket(struct inet_frags *f, struct inet_frag_bucket *hb)
{
	struct inet_frag_queue *fq;
	struct hlist_node *n;
	unsigned int evicted = 0;
	HLIST_HEAD(expired);

	spin_lock(&hb->chain_lock);

	hlist_for_each_entry_safe(fq, n, &hb->chain, list) {
		if (!inet_fragq_should_evict(fq))
			continue;

		if (!del_timer(&fq->timer))
			continue;

		hlist_add_head(&fq->list_evictor, &expired);
		++evicted;
	}

	spin_unlock(&hb->chain_lock);

	hlist_for_each_entry_safe(fq, n, &expired, list_evictor)
		f->frag_expire(&fq->timer);

	return evicted;
}

static void inet_frag_worker(struct work_struct *work)
{
	unsigned int budget = INETFRAGS_EVICT_BUCKETS;
	unsigned int i, evicted = 0;
	struct inet_frags *f;

	f = container_of(work, struct inet_frags, frags_work);

	BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ);

	local_bh_disable();

	for (i = READ_ONCE(f->next_bucket); budget; --budget) {
		evicted += inet_evict_bucket(f, &f->hash[i]);
		i = (i + 1) & (INETFRAGS_HASHSZ - 1);
		if (evicted > INETFRAGS_EVICT_MAX)
			break;
	}

	f->next_bucket = i;

	local_bh_enable();

	if (f->rebuild && inet_frag_may_rebuild(f))
		inet_frag_secret_rebuild(f);
}

static void inet_frag_schedule_worker(struct inet_frags *f)
{
	if (unlikely(!work_pending(&f->frags_work)))
		schedule_work(&f->frags_work);
}

int inet_frags_init(struct inet_frags *f)
{
	int i;

	INIT_WORK(&f->frags_work, inet_frag_worker);

	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
		struct inet_frag_bucket *hb = &f->hash[i];

		spin_lock_init(&hb->chain_lock);
		INIT_HLIST_HEAD(&hb->chain);
	}

	seqlock_init(&f->rnd_seqlock);
	f->last_rebuild_jiffies = 0;
	f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0,
					    NULL);
	if (!f->frags_cachep)
		return -ENOMEM;

	return 0;
}
EXPORT_SYMBOL(inet_frags_init);

void inet_frags_fini(struct inet_frags *f)
{
	cancel_work_sync(&f->frags_work);
	kmem_cache_destroy(f->frags_cachep);
}
EXPORT_SYMBOL(inet_frags_fini);

void inet_frags_exit_net(struct netns_frags *nf)
{
	struct inet_frags *f =nf->f;
	unsigned int seq;
	int i;

	nf->high_thresh = 0; /* prevent creation of new frags */

evict_again:
	local_bh_disable();
	seq = read_seqbegin(&f->rnd_seqlock);

	for (i = 0; i < INETFRAGS_HASHSZ ; i++)
		inet_evict_bucket(f, &f->hash[i]);

	local_bh_enable();
	cond_resched();

	if (read_seqretry(&f->rnd_seqlock, seq) ||
	    sum_frag_mem_limit(nf))
		goto evict_again;
}
EXPORT_SYMBOL(inet_frags_exit_net);

static struct inet_frag_bucket *
get_frag_bucket_locked(struct inet_frag_queue *fq, struct inet_frags *f)
__acquires(hb->chain_lock)
{
	struct inet_frag_bucket *hb;
	unsigned int seq, hash;

 restart:
	seq = read_seqbegin(&f->rnd_seqlock);

	hash = inet_frag_hashfn(f, fq);
	hb = &f->hash[hash];

	spin_lock(&hb->chain_lock);
	if (read_seqretry(&f->rnd_seqlock, seq)) {
		spin_unlock(&hb->chain_lock);
		goto restart;
	}

	return hb;
}

static inline void fq_unlink(struct inet_frag_queue *fq)
{
	struct inet_frag_bucket *hb;

	hb = get_frag_bucket_locked(fq, fq->net->f);
	hlist_del(&fq->list);
	fq->flags |= INET_FRAG_COMPLETE;
	spin_unlock(&hb->chain_lock);
}

void inet_frag_kill(struct inet_frag_queue *fq)
{
	if (del_timer(&fq->timer))
		refcount_dec(&fq->refcnt);

	if (!(fq->flags & INET_FRAG_COMPLETE)) {
		fq_unlink(fq);
		refcount_dec(&fq->refcnt);
	}
}
EXPORT_SYMBOL(inet_frag_kill);

void inet_frag_destroy(struct inet_frag_queue *q)
{
	struct sk_buff *fp;
	struct netns_frags *nf;
	unsigned int sum, sum_truesize = 0;
	struct inet_frags *f;

	WARN_ON(!(q->flags & INET_FRAG_COMPLETE));
	WARN_ON(del_timer(&q->timer) != 0);

	/* Release all fragment data. */
	fp = q->fragments;
	nf = q->net;
	f = nf->f;
	while (fp) {
		struct sk_buff *xp = fp->next;

		sum_truesize += fp->truesize;
		kfree_skb(fp);
		fp = xp;
	}
	sum = sum_truesize + f->qsize;

	if (f->destructor)
		f->destructor(q);
	kmem_cache_free(f->frags_cachep, q);

	sub_frag_mem_limit(nf, sum);
}
EXPORT_SYMBOL(inet_frag_destroy);

static struct inet_frag_queue *inet_frag_intern(struct netns_frags *nf,
						struct inet_frag_queue *qp_in,
						struct inet_frags *f,
						void *arg)
{
	struct inet_frag_bucket *hb = get_frag_bucket_locked(qp_in, f);
	struct inet_frag_queue *qp;

#ifdef CONFIG_SMP
	/* With SMP race we have to recheck hash table, because
	 * such entry could have been created on other cpu before
	 * we acquired hash bucket lock.
	 */
	hlist_for_each_entry(qp, &hb->chain, list) {
		if (qp->net == nf && f->match(qp, arg)) {
			refcount_inc(&qp->refcnt);
			spin_unlock(&hb->chain_lock);
			qp_in->flags |= INET_FRAG_COMPLETE;
			inet_frag_put(qp_in);
			return qp;
		}
	}
#endif
	qp = qp_in;
	if (!mod_timer(&qp->timer, jiffies + nf->timeout))
		refcount_inc(&qp->refcnt);

	refcount_inc(&qp->refcnt);
	hlist_add_head(&qp->list, &hb->chain);

	spin_unlock(&hb->chain_lock);

	return qp;
}

static struct inet_frag_queue *inet_frag_alloc(struct netns_frags *nf,
					       struct inet_frags *f,
					       void *arg)
{
	struct inet_frag_queue *q;

	q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC);
	if (!q)
		return NULL;

	q->net = nf;
	f->constructor(q, arg);
	add_frag_mem_limit(nf, f->qsize);

	timer_setup(&q->timer, f->frag_expire, 0);
	spin_lock_init(&q->lock);
	refcount_set(&q->refcnt, 1);

	return q;
}

static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf,
						struct inet_frags *f,
						void *arg)
{
	struct inet_frag_queue *q;

	q = inet_frag_alloc(nf, f, arg);
	if (!q)
		return NULL;

	return inet_frag_intern(nf, q, f, arg);
}

struct inet_frag_queue *inet_frag_find(struct netns_frags *nf,
				       struct inet_frags *f, void *key,
				       unsigned int hash)
{
	struct inet_frag_bucket *hb;
	struct inet_frag_queue *q;
	int depth = 0;

	if (!nf->high_thresh || frag_mem_limit(nf) > nf->high_thresh) {
		inet_frag_schedule_worker(f);
		return NULL;
	}

	if (frag_mem_limit(nf) > nf->low_thresh)
		inet_frag_schedule_worker(f);

	hash &= (INETFRAGS_HASHSZ - 1);
	hb = &f->hash[hash];

	spin_lock(&hb->chain_lock);
	hlist_for_each_entry(q, &hb->chain, list) {
		if (q->net == nf && f->match(q, key)) {
			refcount_inc(&q->refcnt);
			spin_unlock(&hb->chain_lock);
			return q;
		}
		depth++;
	}
	spin_unlock(&hb->chain_lock);

	if (depth <= INETFRAGS_MAXDEPTH)
		return inet_frag_create(nf, f, key);

	if (inet_frag_may_rebuild(f)) {
		if (!f->rebuild)
			f->rebuild = true;
		inet_frag_schedule_worker(f);
	}

	return ERR_PTR(-ENOBUFS);
}
EXPORT_SYMBOL(inet_frag_find);

void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
				   const char *prefix)
{
	static const char msg[] = "inet_frag_find: Fragment hash bucket"
		" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
		". Dropping fragment.\n";

	if (PTR_ERR(q) == -ENOBUFS)
		net_dbg_ratelimited("%s%s", prefix, msg);
}
EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);
Commit	Line	Data
7eb95156 PE	1	/*
	2	* inet fragments management
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation; either version
	7	* 2 of the License, or (at your option) any later version.
	8	*
	9	* Authors: Pavel Emelyanov <xemul@openvz.org>
	10	* Started as consolidation of ipv4/ip_fragment.c,
	11	* ipv6/reassembly. and ipv6 nf conntrack reassembly
	12	*/
	13
	14	#include <linux/list.h>
	15	#include <linux/spinlock.h>
	16	#include <linux/module.h>
	17	#include <linux/timer.h>
	18	#include <linux/mm.h>
321a3a99	19	#include <linux/random.h>
1e4b8287 PE	20	#include <linux/skbuff.h>
1e4b8287 PE	21	#include <linux/rtnetlink.h>
5a0e3ad6	22	#include <linux/slab.h>
7eb95156	23
5a3da1fe	24	#include <net/sock.h>
7eb95156	25	#include <net/inet_frag.h>
be991971 HFS	26	#include <net/inet_ecn.h>
be991971 HFS	27
b13d3cbf FW	28	#define INETFRAGS_EVICT_BUCKETS 128
	29	#define INETFRAGS_EVICT_MAX 512
	30
e3a57d18 FW	31	/* don't rebuild inetfrag table with new secret more often than this */
	32	#define INETFRAGS_MIN_REBUILD_INTERVAL (5 * HZ)
	33
be991971 HFS	34	/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
	35	* Value : 0xff if frame should be dropped.
	36	* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
	37	*/
	38	const u8 ip_frag_ecn_table[16] = {
	39	/* at least one fragment had CE, and others ECT_0 or ECT_1 */
	40	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0] = INET_ECN_CE,
	41	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_1] = INET_ECN_CE,
	42	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = INET_ECN_CE,
	43
	44	/* invalid combinations : drop frame */
	45	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE] = 0xff,
	46	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_0] = 0xff,
	47	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_1] = 0xff,
	48	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = 0xff,
	49	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0] = 0xff,
	50	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_1] = 0xff,
	51	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = 0xff,
	52	};
	53	EXPORT_SYMBOL(ip_frag_ecn_table);
7eb95156	54
fb3cfe6e FW	55	static unsigned int
	56	inet_frag_hashfn(const struct inet_frags f, const struct inet_frag_queue q)
	57	{
	58	return f->hashfn(q) & (INETFRAGS_HASHSZ - 1);
	59	}
	60
e3a57d18 FW	61	static bool inet_frag_may_rebuild(struct inet_frags *f)
	62	{
	63	return time_after(jiffies,
	64	f->last_rebuild_jiffies + INETFRAGS_MIN_REBUILD_INTERVAL);
	65	}
	66
	67	static void inet_frag_secret_rebuild(struct inet_frags *f)
321a3a99	68	{
321a3a99 PE	69	int i;
321a3a99 PE	70
ab1c724f	71	write_seqlock_bh(&f->rnd_seqlock);
e3a57d18 FW	72
	73	if (!inet_frag_may_rebuild(f))
	74	goto out;
19952cc4	75
321a3a99	76	get_random_bytes(&f->rnd, sizeof(u32));
e3a57d18	77
321a3a99	78	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
19952cc4	79	struct inet_frag_bucket *hb;
321a3a99	80	struct inet_frag_queue *q;
b67bfe0d	81	struct hlist_node *n;
321a3a99	82
19952cc4	83	hb = &f->hash[i];
ab1c724f FW	84	spin_lock(&hb->chain_lock);
ab1c724f FW	85
19952cc4	86	hlist_for_each_entry_safe(q, n, &hb->chain, list) {
fb3cfe6e	87	unsigned int hval = inet_frag_hashfn(f, q);
321a3a99 PE	88
321a3a99 PE	89	if (hval != i) {
19952cc4 JDB	90	struct inet_frag_bucket *hb_dest;
19952cc4 JDB	91
321a3a99 PE	92	hlist_del(&q->list);
	93
	94	/* Relink to new hash chain. */
19952cc4	95	hb_dest = &f->hash[hval];
ab1c724f FW	96
	97	/* This is the only place where we take
	98	* another chain_lock while already holding
	99	* one. As this will not run concurrently,
	100	* we cannot deadlock on hb_dest lock below, if its
	101	* already locked it will be released soon since
	102	* other caller cannot be waiting for hb lock
	103	* that we've taken above.
	104	*/
	105	spin_lock_nested(&hb_dest->chain_lock,
	106	SINGLE_DEPTH_NESTING);
19952cc4	107	hlist_add_head(&q->list, &hb_dest->chain);
ab1c724f	108	spin_unlock(&hb_dest->chain_lock);
321a3a99 PE	109	}
321a3a99 PE	110	}
ab1c724f	111	spin_unlock(&hb->chain_lock);
321a3a99	112	}
321a3a99	113
e3a57d18 FW	114	f->rebuild = false;
	115	f->last_rebuild_jiffies = jiffies;
	116	out:
ab1c724f	117	write_sequnlock_bh(&f->rnd_seqlock);
321a3a99 PE	118	}
321a3a99 PE	119
b13d3cbf FW	120	static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
b13d3cbf FW	121	{
4c9ee5ec KT	122	if (!hlist_unhashed(&q->list_evictor))
	123	return false;
	124
b13d3cbf FW	125	return q->net->low_thresh == 0 \|\|
	126	frag_mem_limit(q->net) >= q->net->low_thresh;
	127	}
	128
	129	static unsigned int
	130	inet_evict_bucket(struct inet_frags f, struct inet_frag_bucket hb)
	131	{
	132	struct inet_frag_queue *fq;
	133	struct hlist_node *n;
	134	unsigned int evicted = 0;
	135	HLIST_HEAD(expired);
	136
b13d3cbf FW	137	spin_lock(&hb->chain_lock);
	138
	139	hlist_for_each_entry_safe(fq, n, &hb->chain, list) {
	140	if (!inet_fragq_should_evict(fq))
	141	continue;
	142
5719b296 FW	143	if (!del_timer(&fq->timer))
5719b296 FW	144	continue;
b13d3cbf	145
d1fe1944	146	hlist_add_head(&fq->list_evictor, &expired);
b13d3cbf FW	147	++evicted;
	148	}
	149
	150	spin_unlock(&hb->chain_lock);
	151
d1fe1944	152	hlist_for_each_entry_safe(fq, n, &expired, list_evictor)
78802011	153	f->frag_expire(&fq->timer);
b13d3cbf FW	154
	155	return evicted;
	156	}
	157
	158	static void inet_frag_worker(struct work_struct *work)
	159	{
	160	unsigned int budget = INETFRAGS_EVICT_BUCKETS;
	161	unsigned int i, evicted = 0;
	162	struct inet_frags *f;
	163
	164	f = container_of(work, struct inet_frags, frags_work);
	165
	166	BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ);
	167
ab1c724f	168	local_bh_disable();
b13d3cbf	169
6aa7de05	170	for (i = READ_ONCE(f->next_bucket); budget; --budget) {
b13d3cbf FW	171	evicted += inet_evict_bucket(f, &f->hash[i]);
	172	i = (i + 1) & (INETFRAGS_HASHSZ - 1);
	173	if (evicted > INETFRAGS_EVICT_MAX)
	174	break;
	175	}
	176
	177	f->next_bucket = i;
	178
ab1c724f FW	179	local_bh_enable();
ab1c724f FW	180
e3a57d18 FW	181	if (f->rebuild && inet_frag_may_rebuild(f))
e3a57d18 FW	182	inet_frag_secret_rebuild(f);
b13d3cbf FW	183	}
	184
	185	static void inet_frag_schedule_worker(struct inet_frags *f)
	186	{
	187	if (unlikely(!work_pending(&f->frags_work)))
	188	schedule_work(&f->frags_work);
	189	}
	190
d4ad4d22	191	int inet_frags_init(struct inet_frags *f)
7eb95156 PE	192	{
	193	int i;
	194
b13d3cbf FW	195	INIT_WORK(&f->frags_work, inet_frag_worker);
b13d3cbf FW	196
19952cc4 JDB	197	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
19952cc4 JDB	198	struct inet_frag_bucket *hb = &f->hash[i];
7eb95156	199
19952cc4 JDB	200	spin_lock_init(&hb->chain_lock);
	201	INIT_HLIST_HEAD(&hb->chain);
	202	}
ab1c724f FW	203
ab1c724f FW	204	seqlock_init(&f->rnd_seqlock);
e3a57d18	205	f->last_rebuild_jiffies = 0;
d4ad4d22 NA	206	f->frags_cachep = kmem_cache_create(f->frags_cache_name, f->qsize, 0, 0,
	207	NULL);
	208	if (!f->frags_cachep)
	209	return -ENOMEM;
	210
	211	return 0;
7eb95156 PE	212	}
	213	EXPORT_SYMBOL(inet_frags_init);
	214
	215	void inet_frags_fini(struct inet_frags *f)
	216	{
b13d3cbf	217	cancel_work_sync(&f->frags_work);
d4ad4d22	218	kmem_cache_destroy(f->frags_cachep);
7eb95156 PE	219	}
7eb95156 PE	220	EXPORT_SYMBOL(inet_frags_fini);
277e650d	221
9bdf9ca9	222	void inet_frags_exit_net(struct netns_frags *nf)
81566e83	223	{
9bdf9ca9	224	struct inet_frags *f =nf->f;
ab1c724f	225	unsigned int seq;
b13d3cbf FW	226	int i;
b13d3cbf FW	227
d2619bcb	228	nf->high_thresh = 0; /* prevent creation of new frags */
e8e16b70	229
ab1c724f	230	evict_again:
5719b296	231	local_bh_disable();
ab1c724f	232	seq = read_seqbegin(&f->rnd_seqlock);
b13d3cbf FW	233
	234	for (i = 0; i < INETFRAGS_HASHSZ ; i++)
	235	inet_evict_bucket(f, &f->hash[i]);
	236
ab1c724f	237	local_bh_enable();
5719b296 FW	238	cond_resched();
	239
	240	if (read_seqretry(&f->rnd_seqlock, seq) \|\|
fb452a1a	241	sum_frag_mem_limit(nf))
5719b296	242	goto evict_again;
81566e83 PE	243	}
	244	EXPORT_SYMBOL(inet_frags_exit_net);
	245
ab1c724f FW	246	static struct inet_frag_bucket *
	247	get_frag_bucket_locked(struct inet_frag_queue fq, struct inet_frags f)
	248	__acquires(hb->chain_lock)
277e650d	249	{
19952cc4	250	struct inet_frag_bucket *hb;
ab1c724f FW	251	unsigned int seq, hash;
	252
	253	restart:
	254	seq = read_seqbegin(&f->rnd_seqlock);
19952cc4	255
fb3cfe6e	256	hash = inet_frag_hashfn(f, fq);
19952cc4 JDB	257	hb = &f->hash[hash];
	258
	259	spin_lock(&hb->chain_lock);
ab1c724f FW	260	if (read_seqretry(&f->rnd_seqlock, seq)) {
	261	spin_unlock(&hb->chain_lock);
	262	goto restart;
	263	}
	264
	265	return hb;
	266	}
	267
9bdf9ca9	268	static inline void fq_unlink(struct inet_frag_queue *fq)
ab1c724f FW	269	{
	270	struct inet_frag_bucket *hb;
	271
9bdf9ca9	272	hb = get_frag_bucket_locked(fq, fq->net->f);
d1fe1944	273	hlist_del(&fq->list);
5719b296	274	fq->flags \|= INET_FRAG_COMPLETE;
19952cc4	275	spin_unlock(&hb->chain_lock);
277e650d PE	276	}
277e650d PE	277
9bdf9ca9	278	void inet_frag_kill(struct inet_frag_queue *fq)
277e650d PE	279	{
277e650d PE	280	if (del_timer(&fq->timer))
edcb6918	281	refcount_dec(&fq->refcnt);
277e650d	282
06aa8b8a	283	if (!(fq->flags & INET_FRAG_COMPLETE)) {
9bdf9ca9	284	fq_unlink(fq);
edcb6918	285	refcount_dec(&fq->refcnt);
277e650d PE	286	}
277e650d PE	287	}
277e650d	288	EXPORT_SYMBOL(inet_frag_kill);
1e4b8287	289
9bdf9ca9	290	void inet_frag_destroy(struct inet_frag_queue *q)
1e4b8287 PE	291	{
1e4b8287 PE	292	struct sk_buff *fp;
6ddc0822	293	struct netns_frags *nf;
d433673e	294	unsigned int sum, sum_truesize = 0;
9bdf9ca9	295	struct inet_frags *f;
1e4b8287	296
06aa8b8a	297	WARN_ON(!(q->flags & INET_FRAG_COMPLETE));
547b792c	298	WARN_ON(del_timer(&q->timer) != 0);
1e4b8287 PE	299
	300	/* Release all fragment data. */
	301	fp = q->fragments;
6ddc0822	302	nf = q->net;
9bdf9ca9	303	f = nf->f;
1e4b8287 PE	304	while (fp) {
	305	struct sk_buff *xp = fp->next;
	306
d433673e	307	sum_truesize += fp->truesize;
a72a5e2d	308	kfree_skb(fp);
1e4b8287 PE	309	fp = xp;
1e4b8287 PE	310	}
d433673e	311	sum = sum_truesize + f->qsize;
1e4b8287	312
c9547709 PE	313	if (f->destructor)
c9547709 PE	314	f->destructor(q);
d4ad4d22	315	kmem_cache_free(f->frags_cachep, q);
5719b296 FW	316
5719b296 FW	317	sub_frag_mem_limit(nf, sum);
1e4b8287 PE	318	}
1e4b8287 PE	319	EXPORT_SYMBOL(inet_frag_destroy);
8e7999c4	320
ac18e750	321	static struct inet_frag_queue inet_frag_intern(struct netns_frags nf,
f926e236 NA	322	struct inet_frag_queue *qp_in,
	323	struct inet_frags *f,
	324	void *arg)
2588fe1d	325	{
ab1c724f	326	struct inet_frag_bucket *hb = get_frag_bucket_locked(qp_in, f);
2588fe1d	327	struct inet_frag_queue *qp;
19952cc4	328
2588fe1d PE	329	#ifdef CONFIG_SMP
2588fe1d PE	330	/* With SMP race we have to recheck hash table, because
ab1c724f FW	331	* such entry could have been created on other cpu before
ab1c724f FW	332	* we acquired hash bucket lock.
2588fe1d	333	*/
19952cc4	334	hlist_for_each_entry(qp, &hb->chain, list) {
ac18e750	335	if (qp->net == nf && f->match(qp, arg)) {
edcb6918	336	refcount_inc(&qp->refcnt);
19952cc4	337	spin_unlock(&hb->chain_lock);
06aa8b8a	338	qp_in->flags \|= INET_FRAG_COMPLETE;
9bdf9ca9	339	inet_frag_put(qp_in);
2588fe1d PE	340	return qp;
	341	}
	342	}
	343	#endif
	344	qp = qp_in;
b2fd5321	345	if (!mod_timer(&qp->timer, jiffies + nf->timeout))
edcb6918	346	refcount_inc(&qp->refcnt);
2588fe1d	347
edcb6918	348	refcount_inc(&qp->refcnt);
19952cc4	349	hlist_add_head(&qp->list, &hb->chain);
3fd588eb	350
19952cc4	351	spin_unlock(&hb->chain_lock);
24b9bf43	352
2588fe1d PE	353	return qp;
2588fe1d PE	354	}
e521db9d	355
ac18e750	356	static struct inet_frag_queue inet_frag_alloc(struct netns_frags nf,
f926e236 NA	357	struct inet_frags *f,
f926e236 NA	358	void *arg)
e521db9d PE	359	{
	360	struct inet_frag_queue *q;
	361
d4ad4d22	362	q = kmem_cache_zalloc(f->frags_cachep, GFP_ATOMIC);
51456b29	363	if (!q)
e521db9d PE	364	return NULL;
e521db9d PE	365
54db0cc2	366	q->net = nf;
c6fda282	367	f->constructor(q, arg);
0e60d245	368	add_frag_mem_limit(nf, f->qsize);
d433673e	369
78802011	370	timer_setup(&q->timer, f->frag_expire, 0);
e521db9d	371	spin_lock_init(&q->lock);
edcb6918	372	refcount_set(&q->refcnt, 1);
e521db9d PE	373
	374	return q;
	375	}
c6fda282	376
ac18e750	377	static struct inet_frag_queue inet_frag_create(struct netns_frags nf,
f926e236 NA	378	struct inet_frags *f,
f926e236 NA	379	void *arg)
c6fda282 PE	380	{
	381	struct inet_frag_queue *q;
	382
ac18e750	383	q = inet_frag_alloc(nf, f, arg);
51456b29	384	if (!q)
c6fda282 PE	385	return NULL;
c6fda282 PE	386
9a375803	387	return inet_frag_intern(nf, q, f, arg);
c6fda282	388	}
abd6523d	389
ac18e750	390	struct inet_frag_queue inet_frag_find(struct netns_frags nf,
f926e236 NA	391	struct inet_frags f, void key,
f926e236 NA	392	unsigned int hash)
abd6523d	393	{
19952cc4	394	struct inet_frag_bucket *hb;
abd6523d	395	struct inet_frag_queue *q;
5a3da1fe	396	int depth = 0;
abd6523d	397
afa6122a ED	398	if (!nf->high_thresh \|\| frag_mem_limit(nf) > nf->high_thresh) {
	399	inet_frag_schedule_worker(f);
	400	return NULL;
	401	}
	402
b13d3cbf FW	403	if (frag_mem_limit(nf) > nf->low_thresh)
b13d3cbf FW	404	inet_frag_schedule_worker(f);
86e93e47	405
fb3cfe6e	406	hash &= (INETFRAGS_HASHSZ - 1);
19952cc4 JDB	407	hb = &f->hash[hash];
	408
	409	spin_lock(&hb->chain_lock);
	410	hlist_for_each_entry(q, &hb->chain, list) {
ac18e750	411	if (q->net == nf && f->match(q, key)) {
edcb6918	412	refcount_inc(&q->refcnt);
19952cc4	413	spin_unlock(&hb->chain_lock);
abd6523d PE	414	return q;
abd6523d PE	415	}
5a3da1fe	416	depth++;
abd6523d	417	}
19952cc4	418	spin_unlock(&hb->chain_lock);
abd6523d	419
5a3da1fe HFS	420	if (depth <= INETFRAGS_MAXDEPTH)
5a3da1fe HFS	421	return inet_frag_create(nf, f, key);
e3a57d18 FW	422
e3a57d18 FW	423	if (inet_frag_may_rebuild(f)) {
ab1c724f FW	424	if (!f->rebuild)
ab1c724f FW	425	f->rebuild = true;
e3a57d18 FW	426	inet_frag_schedule_worker(f);
	427	}
	428
	429	return ERR_PTR(-ENOBUFS);
abd6523d PE	430	}
abd6523d PE	431	EXPORT_SYMBOL(inet_frag_find);
5a3da1fe HFS	432
	433	void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
	434	const char *prefix)
	435	{
	436	static const char msg[] = "inet_frag_find: Fragment hash bucket"
	437	" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
	438	". Dropping fragment.\n";
	439
	440	if (PTR_ERR(q) == -ENOBUFS)
ba7a46f1	441	net_dbg_ratelimited("%s%s", prefix, msg);
5a3da1fe HFS	442	}
5a3da1fe HFS	443	EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);