[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>

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

	write_lock(&f->lock);
	get_random_bytes(&f->rnd, sizeof(u32));
	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
		struct inet_frag_queue *q;
		struct hlist_node *n;

		hlist_for_each_entry_safe(q, n, &f->hash[i], list) {
			unsigned int hval = f->hashfn(q);

			if (hval != i) {
				hlist_del(&q->list);

				/* Relink to new hash chain. */
				hlist_add_head(&q->list, &f->hash[hval]);
			}
		}
	}
	write_unlock(&f->lock);

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

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

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

	rwlock_init(&f->lock);

	f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
				   (jiffies ^ (jiffies >> 6)));

	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)
{
	nf->nqueues = 0;
	init_frag_mem_limit(nf);
	INIT_LIST_HEAD(&nf->lru_list);
	spin_lock_init(&nf->lru_lock);
}
EXPORT_SYMBOL(inet_frags_init_net);

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

void inet_frags_exit_net(struct netns_frags *nf, struct inet_frags *f)
{
	nf->low_thresh = 0;

	local_bh_disable();
	inet_frag_evictor(nf, f, true);
	local_bh_enable();

	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)
{
	write_lock(&f->lock);
	hlist_del(&fq->list);
	fq->net->nqueues--;
	write_unlock(&f->lock);
	inet_frag_lru_del(fq);
}

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,
					int *work)
{
	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;
	if (work)
		*work -= sum;
	sub_frag_mem_limit(q, sum);

	if (f->destructor)
		f->destructor(q);
	kfree(q);

}
EXPORT_SYMBOL(inet_frag_destroy);

int inet_frag_evictor(struct netns_frags *nf, struct inet_frags *f, bool force)
{
	struct inet_frag_queue *q;
	int work, evicted = 0;

	if (!force) {
		if (frag_mem_limit(nf) <= nf->high_thresh)
			return 0;
	}

	work = frag_mem_limit(nf) - nf->low_thresh;
	while (work > 0) {
		spin_lock(&nf->lru_lock);

		if (list_empty(&nf->lru_list)) {
			spin_unlock(&nf->lru_lock);
			break;
		}

		q = list_first_entry(&nf->lru_list,
				struct inet_frag_queue, lru_list);
		atomic_inc(&q->refcnt);
		spin_unlock(&nf->lru_lock);

		spin_lock(&q->lock);
		if (!(q->last_in & INET_FRAG_COMPLETE))
			inet_frag_kill(q, f);
		spin_unlock(&q->lock);

		if (atomic_dec_and_test(&q->refcnt))
			inet_frag_destroy(q, f, &work);
		evicted++;
	}

	return evicted;
}
EXPORT_SYMBOL(inet_frag_evictor);

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_queue *qp;
#ifdef CONFIG_SMP
#endif
	unsigned int hash;

	write_lock(&f->lock);
	/*
	 * 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 = f->hashfn(qp_in);
#ifdef CONFIG_SMP
	/* With SMP race we have to recheck hash table, because
	 * such entry could be created on other cpu, while we
	 * promoted read lock to write lock.
	 */
	hlist_for_each_entry(qp, &f->hash[hash], list) {
		if (qp->net == nf && f->match(qp, arg)) {
			atomic_inc(&qp->refcnt);
			write_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, &f->hash[hash]);
	nf->nqueues++;
	write_unlock(&f->lock);
	inet_frag_lru_add(nf, qp);
	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 = 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_queue *q;
	int depth = 0;

	hlist_for_each_entry(q, &f->hash[hash], list) {
		if (q->net == nf && f->match(q, key)) {
			atomic_inc(&q->refcnt);
			read_unlock(&f->lock);
			return q;
		}
		depth++;
	}
	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>
	27
	28	/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
	29	* Value : 0xff if frame should be dropped.
	30	* 0 or INET_ECN_CE value, to be ORed in to final iph->tos field
	31	*/
	32	const u8 ip_frag_ecn_table[16] = {
	33	/* at least one fragment had CE, and others ECT_0 or ECT_1 */
	34	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0] = INET_ECN_CE,
	35	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_1] = INET_ECN_CE,
	36	[IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = INET_ECN_CE,
	37
	38	/* invalid combinations : drop frame */
	39	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE] = 0xff,
	40	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_0] = 0xff,
	41	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_1] = 0xff,
	42	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = 0xff,
	43	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0] = 0xff,
	44	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_1] = 0xff,
	45	[IPFRAG_ECN_NOT_ECT \| IPFRAG_ECN_CE \| IPFRAG_ECN_ECT_0 \| IPFRAG_ECN_ECT_1] = 0xff,
	46	};
	47	EXPORT_SYMBOL(ip_frag_ecn_table);
7eb95156	48
321a3a99 PE	49	static void inet_frag_secret_rebuild(unsigned long dummy)
	50	{
	51	struct inet_frags f = (struct inet_frags )dummy;
	52	unsigned long now = jiffies;
	53	int i;
	54
	55	write_lock(&f->lock);
	56	get_random_bytes(&f->rnd, sizeof(u32));
	57	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
	58	struct inet_frag_queue *q;
b67bfe0d	59	struct hlist_node *n;
321a3a99	60
b67bfe0d	61	hlist_for_each_entry_safe(q, n, &f->hash[i], list) {
321a3a99 PE	62	unsigned int hval = f->hashfn(q);
	63
	64	if (hval != i) {
	65	hlist_del(&q->list);
	66
	67	/* Relink to new hash chain. */
	68	hlist_add_head(&q->list, &f->hash[hval]);
	69	}
	70	}
	71	}
	72	write_unlock(&f->lock);
	73
3b4bc4a2	74	mod_timer(&f->secret_timer, now + f->secret_interval);
321a3a99 PE	75	}
321a3a99 PE	76
7eb95156 PE	77	void inet_frags_init(struct inet_frags *f)
	78	{
	79	int i;
	80
	81	for (i = 0; i < INETFRAGS_HASHSZ; i++)
	82	INIT_HLIST_HEAD(&f->hash[i]);
	83
7eb95156 PE	84	rwlock_init(&f->lock);
	85
	86	f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
	87	(jiffies ^ (jiffies >> 6)));
	88
b24b8a24 PE	89	setup_timer(&f->secret_timer, inet_frag_secret_rebuild,
b24b8a24 PE	90	(unsigned long)f);
3b4bc4a2	91	f->secret_timer.expires = jiffies + f->secret_interval;
321a3a99	92	add_timer(&f->secret_timer);
7eb95156 PE	93	}
	94	EXPORT_SYMBOL(inet_frags_init);
	95
e5a2bb84 PE	96	void inet_frags_init_net(struct netns_frags *nf)
	97	{
	98	nf->nqueues = 0;
d433673e	99	init_frag_mem_limit(nf);
3140c25c	100	INIT_LIST_HEAD(&nf->lru_list);
3ef0eb0d	101	spin_lock_init(&nf->lru_lock);
e5a2bb84 PE	102	}
	103	EXPORT_SYMBOL(inet_frags_init_net);
	104
7eb95156 PE	105	void inet_frags_fini(struct inet_frags *f)
7eb95156 PE	106	{
321a3a99	107	del_timer(&f->secret_timer);
7eb95156 PE	108	}
7eb95156 PE	109	EXPORT_SYMBOL(inet_frags_fini);
277e650d	110
81566e83 PE	111	void inet_frags_exit_net(struct netns_frags nf, struct inet_frags f)
	112	{
	113	nf->low_thresh = 0;
e8e16b70 DM	114
e8e16b70 DM	115	local_bh_disable();
6b102865	116	inet_frag_evictor(nf, f, true);
e8e16b70	117	local_bh_enable();
6d7b857d JDB	118
6d7b857d JDB	119	percpu_counter_destroy(&nf->mem);
81566e83 PE	120	}
	121	EXPORT_SYMBOL(inet_frags_exit_net);
	122
277e650d PE	123	static inline void fq_unlink(struct inet_frag_queue fq, struct inet_frags f)
	124	{
	125	write_lock(&f->lock);
	126	hlist_del(&fq->list);
e5a2bb84	127	fq->net->nqueues--;
277e650d	128	write_unlock(&f->lock);
3ef0eb0d	129	inet_frag_lru_del(fq);
277e650d PE	130	}
	131
	132	void inet_frag_kill(struct inet_frag_queue fq, struct inet_frags f)
	133	{
	134	if (del_timer(&fq->timer))
	135	atomic_dec(&fq->refcnt);
	136
bc578a54	137	if (!(fq->last_in & INET_FRAG_COMPLETE)) {
277e650d PE	138	fq_unlink(fq, f);
277e650d PE	139	atomic_dec(&fq->refcnt);
bc578a54	140	fq->last_in \|= INET_FRAG_COMPLETE;
277e650d PE	141	}
277e650d PE	142	}
277e650d	143	EXPORT_SYMBOL(inet_frag_kill);
1e4b8287	144
6ddc0822	145	static inline void frag_kfree_skb(struct netns_frags nf, struct inet_frags f,
d433673e	146	struct sk_buff *skb)
1e4b8287	147	{
1e4b8287 PE	148	if (f->skb_free)
	149	f->skb_free(skb);
	150	kfree_skb(skb);
	151	}
	152
	153	void inet_frag_destroy(struct inet_frag_queue q, struct inet_frags f,
	154	int *work)
	155	{
	156	struct sk_buff *fp;
6ddc0822	157	struct netns_frags *nf;
d433673e	158	unsigned int sum, sum_truesize = 0;
1e4b8287	159
547b792c IJ	160	WARN_ON(!(q->last_in & INET_FRAG_COMPLETE));
547b792c IJ	161	WARN_ON(del_timer(&q->timer) != 0);
1e4b8287 PE	162
	163	/* Release all fragment data. */
	164	fp = q->fragments;
6ddc0822	165	nf = q->net;
1e4b8287 PE	166	while (fp) {
	167	struct sk_buff *xp = fp->next;
	168
d433673e JDB	169	sum_truesize += fp->truesize;
d433673e JDB	170	frag_kfree_skb(nf, f, fp);
1e4b8287 PE	171	fp = xp;
1e4b8287 PE	172	}
d433673e	173	sum = sum_truesize + f->qsize;
1e4b8287	174	if (work)
d433673e JDB	175	*work -= sum;
d433673e JDB	176	sub_frag_mem_limit(q, sum);
1e4b8287	177
c9547709 PE	178	if (f->destructor)
	179	f->destructor(q);
	180	kfree(q);
1e4b8287 PE	181
	182	}
	183	EXPORT_SYMBOL(inet_frag_destroy);
8e7999c4	184
6b102865	185	int inet_frag_evictor(struct netns_frags nf, struct inet_frags f, bool force)
8e7999c4 PE	186	{
	187	struct inet_frag_queue *q;
	188	int work, evicted = 0;
	189
6b102865	190	if (!force) {
d433673e	191	if (frag_mem_limit(nf) <= nf->high_thresh)
6b102865 AW	192	return 0;
	193	}
	194
d433673e	195	work = frag_mem_limit(nf) - nf->low_thresh;
8e7999c4	196	while (work > 0) {
3ef0eb0d JDB	197	spin_lock(&nf->lru_lock);
3ef0eb0d JDB	198
3140c25c	199	if (list_empty(&nf->lru_list)) {
3ef0eb0d	200	spin_unlock(&nf->lru_lock);
8e7999c4 PE	201	break;
	202	}
	203
3140c25c	204	q = list_first_entry(&nf->lru_list,
8e7999c4 PE	205	struct inet_frag_queue, lru_list);
8e7999c4 PE	206	atomic_inc(&q->refcnt);
3ef0eb0d	207	spin_unlock(&nf->lru_lock);
8e7999c4 PE	208
8e7999c4 PE	209	spin_lock(&q->lock);
bc578a54	210	if (!(q->last_in & INET_FRAG_COMPLETE))
8e7999c4 PE	211	inet_frag_kill(q, f);
	212	spin_unlock(&q->lock);
	213
	214	if (atomic_dec_and_test(&q->refcnt))
	215	inet_frag_destroy(q, f, &work);
	216	evicted++;
	217	}
	218
	219	return evicted;
	220	}
	221	EXPORT_SYMBOL(inet_frag_evictor);
2588fe1d	222
ac18e750 PE	223	static struct inet_frag_queue inet_frag_intern(struct netns_frags nf,
ac18e750 PE	224	struct inet_frag_queue qp_in, struct inet_frags f,
9a375803	225	void *arg)
2588fe1d PE	226	{
	227	struct inet_frag_queue *qp;
	228	#ifdef CONFIG_SMP
2588fe1d	229	#endif
9a375803	230	unsigned int hash;
2588fe1d PE	231
2588fe1d PE	232	write_lock(&f->lock);
9a375803 PE	233	/*
	234	* While we stayed w/o the lock other CPU could update
	235	* the rnd seed, so we need to re-calculate the hash
	236	* chain. Fortunatelly the qp_in can be used to get one.
	237	*/
	238	hash = f->hashfn(qp_in);
2588fe1d PE	239	#ifdef CONFIG_SMP
	240	/* With SMP race we have to recheck hash table, because
	241	* such entry could be created on other cpu, while we
	242	* promoted read lock to write lock.
	243	*/
b67bfe0d	244	hlist_for_each_entry(qp, &f->hash[hash], list) {
ac18e750	245	if (qp->net == nf && f->match(qp, arg)) {
2588fe1d PE	246	atomic_inc(&qp->refcnt);
2588fe1d PE	247	write_unlock(&f->lock);
bc578a54	248	qp_in->last_in \|= INET_FRAG_COMPLETE;
2588fe1d PE	249	inet_frag_put(qp_in, f);
	250	return qp;
	251	}
	252	}
	253	#endif
	254	qp = qp_in;
b2fd5321	255	if (!mod_timer(&qp->timer, jiffies + nf->timeout))
2588fe1d PE	256	atomic_inc(&qp->refcnt);
	257
	258	atomic_inc(&qp->refcnt);
	259	hlist_add_head(&qp->list, &f->hash[hash]);
e5a2bb84	260	nf->nqueues++;
2588fe1d	261	write_unlock(&f->lock);
3ef0eb0d	262	inet_frag_lru_add(nf, qp);
2588fe1d PE	263	return qp;
2588fe1d PE	264	}
e521db9d	265
ac18e750 PE	266	static struct inet_frag_queue inet_frag_alloc(struct netns_frags nf,
ac18e750 PE	267	struct inet_frags f, void arg)
e521db9d PE	268	{
	269	struct inet_frag_queue *q;
	270
	271	q = kzalloc(f->qsize, GFP_ATOMIC);
	272	if (q == NULL)
	273	return NULL;
	274
54db0cc2	275	q->net = nf;
c6fda282	276	f->constructor(q, arg);
d433673e JDB	277	add_frag_mem_limit(q, f->qsize);
d433673e JDB	278
e521db9d PE	279	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
	280	spin_lock_init(&q->lock);
	281	atomic_set(&q->refcnt, 1);
	282
	283	return q;
	284	}
c6fda282	285
ac18e750	286	static struct inet_frag_queue inet_frag_create(struct netns_frags nf,
9a375803	287	struct inet_frags f, void arg)
c6fda282 PE	288	{
	289	struct inet_frag_queue *q;
	290
ac18e750	291	q = inet_frag_alloc(nf, f, arg);
c6fda282 PE	292	if (q == NULL)
	293	return NULL;
	294
9a375803	295	return inet_frag_intern(nf, q, f, arg);
c6fda282	296	}
abd6523d	297
ac18e750 PE	298	struct inet_frag_queue inet_frag_find(struct netns_frags nf,
ac18e750 PE	299	struct inet_frags f, void key, unsigned int hash)
56bca31f	300	__releases(&f->lock)
abd6523d PE	301	{
abd6523d PE	302	struct inet_frag_queue *q;
5a3da1fe	303	int depth = 0;
abd6523d	304
b67bfe0d	305	hlist_for_each_entry(q, &f->hash[hash], list) {
ac18e750	306	if (q->net == nf && f->match(q, key)) {
abd6523d PE	307	atomic_inc(&q->refcnt);
	308	read_unlock(&f->lock);
	309	return q;
	310	}
5a3da1fe	311	depth++;
abd6523d PE	312	}
	313	read_unlock(&f->lock);
	314
5a3da1fe HFS	315	if (depth <= INETFRAGS_MAXDEPTH)
	316	return inet_frag_create(nf, f, key);
	317	else
	318	return ERR_PTR(-ENOBUFS);
abd6523d PE	319	}
abd6523d PE	320	EXPORT_SYMBOL(inet_frag_find);
5a3da1fe HFS	321
	322	void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
	323	const char *prefix)
	324	{
	325	static const char msg[] = "inet_frag_find: Fragment hash bucket"
	326	" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
	327	". Dropping fragment.\n";
	328
	329	if (PTR_ERR(q) == -ENOBUFS)
	330	LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
	331	}
	332	EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);