[deliverable/linux.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

/* 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 void inet_frag_secret_rebuild(unsigned long dummy)
{
	struct inet_frags *f = (struct inet_frags *)dummy;
	unsigned long now = jiffies;
	int i;

	/* Per bucket lock NOT needed here, due to write lock protection */
	write_lock(&f->lock);

	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];
		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];
				hlist_add_head(&q->list, &hb_dest->chain);
			}
		}
	}
	write_unlock(&f->lock);

	mod_timer(&f->secret_timer, now + f->secret_interval);
}

static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
{
	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);

evict_again:
	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)) {
			/* q expiring right now thus increment its refcount so
			 * it won't be freed under us and wait until the timer
			 * has finished executing then destroy it
			 */
			atomic_inc(&fq->refcnt);
			spin_unlock(&hb->chain_lock);
			del_timer_sync(&fq->timer);
			WARN_ON(atomic_read(&fq->refcnt) != 1);
			inet_frag_put(fq, f);
			goto evict_again;
		}

		/* suppress xmit of (icmp) error packet */
		fq->last_in &= ~INET_FRAG_FIRST_IN;
		fq->last_in |= INET_FRAG_EVICTED;
		hlist_del(&fq->list);
		hlist_add_head(&fq->list, &expired);
		++evicted;
	}

	spin_unlock(&hb->chain_lock);

	hlist_for_each_entry_safe(fq, n, &expired, list)
		f->frag_expire((unsigned long) fq);

	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);

	read_lock_bh(&f->lock);

	for (i = ACCESS_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;

	read_unlock_bh(&f->lock);
}

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

void 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);
	}
	rwlock_init(&f->lock);

	setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
			(unsigned long)f);
	f->secret_timer.expires = jiffies + f->secret_interval;
	add_timer(&f->secret_timer);
}
EXPORT_SYMBOL(inet_frags_init);

void inet_frags_init_net(struct netns_frags *nf)
{
	init_frag_mem_limit(nf);
}
EXPORT_SYMBOL(inet_frags_init_net);

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

void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f)
{
	int i;

	nf->low_thresh = 0;

	read_lock_bh(&f->lock);

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

	read_unlock_bh(&f->lock);

	percpu_counter_destroy(&nf->mem);
}
EXPORT_SYMBOL(inet_frags_exit_net);

static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
{
	struct inet_frag_bucket *hb;
	unsigned int hash;

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

	spin_lock(&hb->chain_lock);
	hlist_del(&fq->list);
	spin_unlock(&hb->chain_lock);

	read_unlock(&f->lock);
}

void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
{
	if (del_timer(&fq->timer))
		atomic_dec(&fq->refcnt);

	if (!(fq->last_in & INET_FRAG_COMPLETE)) {
		fq_unlink(fq, f);
		atomic_dec(&fq->refcnt);
		fq->last_in |= INET_FRAG_COMPLETE;
	}
}
EXPORT_SYMBOL(inet_frag_kill);

static inline void frag_kfree_skb(struct netns_frags *nf, struct inet_frags *f,
		struct sk_buff *skb)
{
	if (f->skb_free)
		f->skb_free(skb);
	kfree_skb(skb);
}

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

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

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

		sum_truesize += fp->truesize;
		frag_kfree_skb(nf, f, fp);
		fp = xp;
	}
	sum = sum_truesize + f->qsize;
	sub_frag_mem_limit(q, sum);

	if (f->destructor)
		f->destructor(q);
	kfree(q);
}
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;
	struct inet_frag_queue *qp;
	unsigned int hash;

	read_lock(&f->lock); /* Protects against hash rebuild */
	/*
	 * While we stayed w/o the lock other CPU could update
	 * the rnd seed, so we need to re-calculate the hash
	 * chain. Fortunatelly the qp_in can be used to get one.
	 */
	hash = inet_frag_hashfn(f, qp_in);
	hb = &f->hash[hash];
	spin_lock(&hb->chain_lock);

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

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

	spin_unlock(&hb->chain_lock);
	read_unlock(&f->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;

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

	q = kzalloc(f->qsize, GFP_ATOMIC);
	if (q == NULL)
		return NULL;

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

	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
	spin_lock_init(&q->lock);
	atomic_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 == NULL)
		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)
	__releases(&f->lock)
{
	struct inet_frag_bucket *hb;
	struct inet_frag_queue *q;
	int depth = 0;

	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)) {
			atomic_inc(&q->refcnt);
			spin_unlock(&hb->chain_lock);
			read_unlock(&f->lock);
			return q;
		}
		depth++;
	}
	spin_unlock(&hb->chain_lock);
	read_unlock(&f->lock);

	if (depth <= INETFRAGS_MAXDEPTH)
		return inet_frag_create(nf, f, key);
	else
		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)
		LIMIT_NETDEBUG(KERN_WARNING "%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
be991971 HFS	31	/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
	32	* Value : 0xff if frame should be dropped.
	33	* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
	34	*/
	35	const u8 ip_frag_ecn_table[16] = {
	36	/* at least one fragment had CE, and others ECT_0 or ECT_1 */
	37	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0] = INET_ECN_CE,
	38	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_1] = INET_ECN_CE,
	39	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = INET_ECN_CE,
	40
	41	/* invalid combinations : drop frame */
	42	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE] = 0xff,
	43	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_0] = 0xff,
	44	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_1] = 0xff,
	45	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = 0xff,
	46	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0] = 0xff,
	47	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_1] = 0xff,
	48	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = 0xff,
	49	};
	50	EXPORT_SYMBOL(ip_frag_ecn_table);
7eb95156	51
fb3cfe6e FW	52	static unsigned int
	53	inet_frag_hashfn(const struct inet_frags f, const struct inet_frag_queue q)
	54	{
	55	return f->hashfn(q) & (INETFRAGS_HASHSZ - 1);
	56	}
	57
321a3a99 PE	58	static void inet_frag_secret_rebuild(unsigned long dummy)
	59	{
	60	struct inet_frags f = (struct inet_frags )dummy;
	61	unsigned long now = jiffies;
	62	int i;
	63
19952cc4	64	/* Per bucket lock NOT needed here, due to write lock protection */
321a3a99	65	write_lock(&f->lock);
19952cc4	66
321a3a99 PE	67	get_random_bytes(&f->rnd, sizeof(u32));
321a3a99 PE	68	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
19952cc4	69	struct inet_frag_bucket *hb;
321a3a99	70	struct inet_frag_queue *q;
b67bfe0d	71	struct hlist_node *n;
321a3a99	72
19952cc4 JDB	73	hb = &f->hash[i];
19952cc4 JDB	74	hlist_for_each_entry_safe(q, n, &hb->chain, list) {
fb3cfe6e	75	unsigned int hval = inet_frag_hashfn(f, q);
321a3a99 PE	76
321a3a99 PE	77	if (hval != i) {
19952cc4 JDB	78	struct inet_frag_bucket *hb_dest;
19952cc4 JDB	79
321a3a99 PE	80	hlist_del(&q->list);
	81
	82	/* Relink to new hash chain. */
19952cc4 JDB	83	hb_dest = &f->hash[hval];
19952cc4 JDB	84	hlist_add_head(&q->list, &hb_dest->chain);
321a3a99 PE	85	}
	86	}
	87	}
	88	write_unlock(&f->lock);
	89
3b4bc4a2	90	mod_timer(&f->secret_timer, now + f->secret_interval);
321a3a99 PE	91	}
321a3a99 PE	92
b13d3cbf FW	93	static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
	94	{
	95	return q->net->low_thresh == 0 \|\|
	96	frag_mem_limit(q->net) >= q->net->low_thresh;
	97	}
	98
	99	static unsigned int
	100	inet_evict_bucket(struct inet_frags f, struct inet_frag_bucket hb)
	101	{
	102	struct inet_frag_queue *fq;
	103	struct hlist_node *n;
	104	unsigned int evicted = 0;
	105	HLIST_HEAD(expired);
	106
	107	evict_again:
	108	spin_lock(&hb->chain_lock);
	109
	110	hlist_for_each_entry_safe(fq, n, &hb->chain, list) {
	111	if (!inet_fragq_should_evict(fq))
	112	continue;
	113
	114	if (!del_timer(&fq->timer)) {
	115	/* q expiring right now thus increment its refcount so
	116	* it won't be freed under us and wait until the timer
	117	* has finished executing then destroy it
	118	*/
	119	atomic_inc(&fq->refcnt);
	120	spin_unlock(&hb->chain_lock);
	121	del_timer_sync(&fq->timer);
	122	WARN_ON(atomic_read(&fq->refcnt) != 1);
	123	inet_frag_put(fq, f);
	124	goto evict_again;
	125	}
	126
	127	/* suppress xmit of (icmp) error packet */
	128	fq->last_in &= ~INET_FRAG_FIRST_IN;
	129	fq->last_in \|= INET_FRAG_EVICTED;
	130	hlist_del(&fq->list);
	131	hlist_add_head(&fq->list, &expired);
	132	++evicted;
	133	}
	134
	135	spin_unlock(&hb->chain_lock);
	136
	137	hlist_for_each_entry_safe(fq, n, &expired, list)
	138	f->frag_expire((unsigned long) fq);
	139
	140	return evicted;
	141	}
	142
	143	static void inet_frag_worker(struct work_struct *work)
	144	{
	145	unsigned int budget = INETFRAGS_EVICT_BUCKETS;
	146	unsigned int i, evicted = 0;
	147	struct inet_frags *f;
	148
	149	f = container_of(work, struct inet_frags, frags_work);
	150
	151	BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ);
	152
	153	read_lock_bh(&f->lock);
	154
	155	for (i = ACCESS_ONCE(f->next_bucket); budget; --budget) {
	156	evicted += inet_evict_bucket(f, &f->hash[i]);
157	i = (i + 1) & (INETFRAGS_HASHSZ - 1);
158	if (evicted > INETFRAGS_EVICT_MAX)
159	break;
160	}
161
162	f->next_bucket = i;
163
164	read_unlock_bh(&f->lock);
165	}
166
167	static void inet_frag_schedule_worker(struct inet_frags *f)
168	{
169	if (unlikely(!work_pending(&f->frags_work)))
170	schedule_work(&f->frags_work);
171	}
172
7eb95156 PE	173	void inet_frags_init(struct inet_frags *f)
	174	{
	175	int i;
	176
b13d3cbf FW	177	INIT_WORK(&f->frags_work, inet_frag_worker);
b13d3cbf FW	178
19952cc4 JDB	179	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
19952cc4 JDB	180	struct inet_frag_bucket *hb = &f->hash[i];
7eb95156	181
19952cc4 JDB	182	spin_lock_init(&hb->chain_lock);
	183	INIT_HLIST_HEAD(&hb->chain);
	184	}
7eb95156 PE	185	rwlock_init(&f->lock);
7eb95156 PE	186
b24b8a24 PE	187	setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
b24b8a24 PE	188	(unsigned long)f);
3b4bc4a2	189	f->secret_timer.expires = jiffies + f->secret_interval;
321a3a99	190	add_timer(&f->secret_timer);
7eb95156 PE	191	}
	192	EXPORT_SYMBOL(inet_frags_init);
	193
e5a2bb84 PE	194	void inet_frags_init_net(struct netns_frags *nf)
e5a2bb84 PE	195	{
d433673e	196	init_frag_mem_limit(nf);
e5a2bb84 PE	197	}
	198	EXPORT_SYMBOL(inet_frags_init_net);
	199
7eb95156 PE	200	void inet_frags_fini(struct inet_frags *f)
7eb95156 PE	201	{
321a3a99	202	del_timer(&f->secret_timer);
b13d3cbf	203	cancel_work_sync(&f->frags_work);
7eb95156 PE	204	}
7eb95156 PE	205	EXPORT_SYMBOL(inet_frags_fini);
277e650d	206
81566e83 PE	207	void inet_frags_exit_net(struct netns_frags nf, struct inet_frags f)
81566e83 PE	208	{
b13d3cbf FW	209	int i;
b13d3cbf FW	210
81566e83	211	nf->low_thresh = 0;
e8e16b70	212
b13d3cbf FW	213	read_lock_bh(&f->lock);
	214
	215	for (i = 0; i < INETFRAGS_HASHSZ ; i++)
	216	inet_evict_bucket(f, &f->hash[i]);
	217
	218	read_unlock_bh(&f->lock);
6d7b857d JDB	219
6d7b857d JDB	220	percpu_counter_destroy(&nf->mem);
81566e83 PE	221	}
	222	EXPORT_SYMBOL(inet_frags_exit_net);
	223
277e650d PE	224	static inline void fq_unlink(struct inet_frag_queue fq, struct inet_frags f)
277e650d PE	225	{
19952cc4 JDB	226	struct inet_frag_bucket *hb;
	227	unsigned int hash;
	228
	229	read_lock(&f->lock);
fb3cfe6e	230	hash = inet_frag_hashfn(f, fq);
19952cc4 JDB	231	hb = &f->hash[hash];
	232
	233	spin_lock(&hb->chain_lock);
277e650d	234	hlist_del(&fq->list);
19952cc4 JDB	235	spin_unlock(&hb->chain_lock);
	236
	237	read_unlock(&f->lock);
277e650d PE	238	}
	239
	240	void inet_frag_kill(struct inet_frag_queue fq, struct inet_frags f)
	241	{
	242	if (del_timer(&fq->timer))
	243	atomic_dec(&fq->refcnt);
	244
bc578a54	245	if (!(fq->last_in & INET_FRAG_COMPLETE)) {
277e650d PE	246	fq_unlink(fq, f);
277e650d PE	247	atomic_dec(&fq->refcnt);
bc578a54	248	fq->last_in \|= INET_FRAG_COMPLETE;
277e650d PE	249	}
277e650d PE	250	}
277e650d	251	EXPORT_SYMBOL(inet_frag_kill);
1e4b8287	252
6ddc0822	253	static inline void frag_kfree_skb(struct netns_frags nf, struct inet_frags f,
d433673e	254	struct sk_buff *skb)
1e4b8287	255	{
1e4b8287 PE	256	if (f->skb_free)
	257	f->skb_free(skb);
	258	kfree_skb(skb);
	259	}
	260
3fd588eb	261	void inet_frag_destroy(struct inet_frag_queue q, struct inet_frags f)
1e4b8287 PE	262	{
1e4b8287 PE	263	struct sk_buff *fp;
6ddc0822	264	struct netns_frags *nf;
d433673e	265	unsigned int sum, sum_truesize = 0;
1e4b8287	266
547b792c IJ	267	WARN_ON(!(q->last_in & INET_FRAG_COMPLETE));
547b792c IJ	268	WARN_ON(del_timer(&q->timer) != 0);
1e4b8287 PE	269
	270	/* Release all fragment data. */
	271	fp = q->fragments;
6ddc0822	272	nf = q->net;
1e4b8287 PE	273	while (fp) {
	274	struct sk_buff *xp = fp->next;
	275
d433673e JDB	276	sum_truesize += fp->truesize;
d433673e JDB	277	frag_kfree_skb(nf, f, fp);
1e4b8287 PE	278	fp = xp;
1e4b8287 PE	279	}
d433673e	280	sum = sum_truesize + f->qsize;
d433673e	281	sub_frag_mem_limit(q, sum);
1e4b8287	282
c9547709 PE	283	if (f->destructor)
	284	f->destructor(q);
	285	kfree(q);
1e4b8287 PE	286	}
1e4b8287 PE	287	EXPORT_SYMBOL(inet_frag_destroy);
8e7999c4	288
ac18e750 PE	289	static struct inet_frag_queue inet_frag_intern(struct netns_frags nf,
ac18e750 PE	290	struct inet_frag_queue qp_in, struct inet_frags f,
9a375803	291	void *arg)
2588fe1d	292	{
19952cc4	293	struct inet_frag_bucket *hb;
2588fe1d	294	struct inet_frag_queue *qp;
9a375803	295	unsigned int hash;
2588fe1d	296
19952cc4	297	read_lock(&f->lock); /* Protects against hash rebuild */
9a375803 PE	298	/*
	299	* While we stayed w/o the lock other CPU could update
	300	* the rnd seed, so we need to re-calculate the hash
	301	* chain. Fortunatelly the qp_in can be used to get one.
	302	*/
fb3cfe6e	303	hash = inet_frag_hashfn(f, qp_in);
19952cc4 JDB	304	hb = &f->hash[hash];
	305	spin_lock(&hb->chain_lock);
	306
2588fe1d PE	307	#ifdef CONFIG_SMP
	308	/* With SMP race we have to recheck hash table, because
	309	* such entry could be created on other cpu, while we
19952cc4	310	* released the hash bucket lock.
2588fe1d	311	*/
19952cc4	312	hlist_for_each_entry(qp, &hb->chain, list) {
ac18e750	313	if (qp->net == nf && f->match(qp, arg)) {
2588fe1d	314	atomic_inc(&qp->refcnt);
19952cc4 JDB	315	spin_unlock(&hb->chain_lock);
19952cc4 JDB	316	read_unlock(&f->lock);
bc578a54	317	qp_in->last_in \|= INET_FRAG_COMPLETE;
2588fe1d PE	318	inet_frag_put(qp_in, f);
	319	return qp;
	320	}
	321	}
	322	#endif
	323	qp = qp_in;
b2fd5321	324	if (!mod_timer(&qp->timer, jiffies + nf->timeout))
2588fe1d PE	325	atomic_inc(&qp->refcnt);
	326
	327	atomic_inc(&qp->refcnt);
19952cc4	328	hlist_add_head(&qp->list, &hb->chain);
3fd588eb	329
19952cc4 JDB	330	spin_unlock(&hb->chain_lock);
19952cc4 JDB	331	read_unlock(&f->lock);
24b9bf43	332
2588fe1d PE	333	return qp;
2588fe1d PE	334	}
e521db9d	335
ac18e750 PE	336	static struct inet_frag_queue inet_frag_alloc(struct netns_frags nf,
ac18e750 PE	337	struct inet_frags f, void arg)
e521db9d PE	338	{
	339	struct inet_frag_queue *q;
	340
b13d3cbf FW	341	if (frag_mem_limit(nf) > nf->high_thresh) {
b13d3cbf FW	342	inet_frag_schedule_worker(f);
86e93e47	343	return NULL;
b13d3cbf	344	}
86e93e47	345
e521db9d PE	346	q = kzalloc(f->qsize, GFP_ATOMIC);
	347	if (q == NULL)
	348	return NULL;
	349
54db0cc2	350	q->net = nf;
c6fda282	351	f->constructor(q, arg);
d433673e JDB	352	add_frag_mem_limit(q, f->qsize);
d433673e JDB	353
e521db9d PE	354	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
	355	spin_lock_init(&q->lock);
	356	atomic_set(&q->refcnt, 1);
	357
	358	return q;
	359	}
c6fda282	360
ac18e750	361	static struct inet_frag_queue inet_frag_create(struct netns_frags nf,
9a375803	362	struct inet_frags f, void arg)
c6fda282 PE	363	{
	364	struct inet_frag_queue *q;
	365
ac18e750	366	q = inet_frag_alloc(nf, f, arg);
c6fda282 PE	367	if (q == NULL)
	368	return NULL;
	369
9a375803	370	return inet_frag_intern(nf, q, f, arg);
c6fda282	371	}
abd6523d	372
ac18e750 PE	373	struct inet_frag_queue inet_frag_find(struct netns_frags nf,
ac18e750 PE	374	struct inet_frags f, void key, unsigned int hash)
56bca31f	375	__releases(&f->lock)
abd6523d	376	{
19952cc4	377	struct inet_frag_bucket *hb;
abd6523d	378	struct inet_frag_queue *q;
5a3da1fe	379	int depth = 0;
abd6523d	380
b13d3cbf FW	381	if (frag_mem_limit(nf) > nf->low_thresh)
b13d3cbf FW	382	inet_frag_schedule_worker(f);
86e93e47	383
fb3cfe6e	384	hash &= (INETFRAGS_HASHSZ - 1);
19952cc4 JDB	385	hb = &f->hash[hash];
	386
	387	spin_lock(&hb->chain_lock);
	388	hlist_for_each_entry(q, &hb->chain, list) {
ac18e750	389	if (q->net == nf && f->match(q, key)) {
abd6523d	390	atomic_inc(&q->refcnt);
19952cc4	391	spin_unlock(&hb->chain_lock);
abd6523d PE	392	read_unlock(&f->lock);
	393	return q;
	394	}
5a3da1fe	395	depth++;
abd6523d	396	}
19952cc4	397	spin_unlock(&hb->chain_lock);
abd6523d PE	398	read_unlock(&f->lock);
abd6523d PE	399
5a3da1fe HFS	400	if (depth <= INETFRAGS_MAXDEPTH)
	401	return inet_frag_create(nf, f, key);
	402	else
	403	return ERR_PTR(-ENOBUFS);
abd6523d PE	404	}
abd6523d PE	405	EXPORT_SYMBOL(inet_frag_find);
5a3da1fe HFS	406
	407	void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
	408	const char *prefix)
	409	{
	410	static const char msg[] = "inet_frag_find: Fragment hash bucket"
	411	" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
	412	". Dropping fragment.\n";
	413
	414	if (PTR_ERR(q) == -ENOBUFS)
	415	LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
	416	}
	417	EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);