[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

/* 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;

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

	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];
		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);
			}
		}
	}

	f->rebuild = false;
	f->last_rebuild_jiffies = jiffies;
out:
	write_unlock_bh(&f->lock);
}

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);
	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);
}

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);
	f->last_rebuild_jiffies = 0;
}
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)
{
	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);

	if (inet_frag_may_rebuild(f)) {
		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)
		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
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
19952cc4	71	/* Per bucket lock NOT needed here, due to write lock protection */
e3a57d18 FW	72	write_lock_bh(&f->lock);
	73
	74	if (!inet_frag_may_rebuild(f))
	75	goto out;
19952cc4	76
321a3a99	77	get_random_bytes(&f->rnd, sizeof(u32));
e3a57d18	78
321a3a99	79	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
19952cc4	80	struct inet_frag_bucket *hb;
321a3a99	81	struct inet_frag_queue *q;
b67bfe0d	82	struct hlist_node *n;
321a3a99	83
19952cc4 JDB	84	hb = &f->hash[i];
19952cc4 JDB	85	hlist_for_each_entry_safe(q, n, &hb->chain, list) {
fb3cfe6e	86	unsigned int hval = inet_frag_hashfn(f, q);
321a3a99 PE	87
321a3a99 PE	88	if (hval != i) {
19952cc4 JDB	89	struct inet_frag_bucket *hb_dest;
19952cc4 JDB	90
321a3a99 PE	91	hlist_del(&q->list);
	92
	93	/* Relink to new hash chain. */
19952cc4 JDB	94	hb_dest = &f->hash[hval];
19952cc4 JDB	95	hlist_add_head(&q->list, &hb_dest->chain);
321a3a99 PE	96	}
	97	}
	98	}
321a3a99	99
e3a57d18 FW	100	f->rebuild = false;
	101	f->last_rebuild_jiffies = jiffies;
	102	out:
	103	write_unlock_bh(&f->lock);
321a3a99 PE	104	}
321a3a99 PE	105
b13d3cbf FW	106	static bool inet_fragq_should_evict(const struct inet_frag_queue *q)
	107	{
	108	return q->net->low_thresh == 0 \|\|
	109	frag_mem_limit(q->net) >= q->net->low_thresh;
	110	}
	111
	112	static unsigned int
	113	inet_evict_bucket(struct inet_frags f, struct inet_frag_bucket hb)
	114	{
	115	struct inet_frag_queue *fq;
	116	struct hlist_node *n;
	117	unsigned int evicted = 0;
	118	HLIST_HEAD(expired);
	119
	120	evict_again:
	121	spin_lock(&hb->chain_lock);
	122
	123	hlist_for_each_entry_safe(fq, n, &hb->chain, list) {
	124	if (!inet_fragq_should_evict(fq))
	125	continue;
	126
	127	if (!del_timer(&fq->timer)) {
	128	/* q expiring right now thus increment its refcount so
	129	* it won't be freed under us and wait until the timer
	130	* has finished executing then destroy it
	131	*/
	132	atomic_inc(&fq->refcnt);
	133	spin_unlock(&hb->chain_lock);
	134	del_timer_sync(&fq->timer);
	135	WARN_ON(atomic_read(&fq->refcnt) != 1);
	136	inet_frag_put(fq, f);
	137	goto evict_again;
	138	}
	139
	140	/* suppress xmit of (icmp) error packet */
	141	fq->last_in &= ~INET_FRAG_FIRST_IN;
	142	fq->last_in \|= INET_FRAG_EVICTED;
	143	hlist_del(&fq->list);
	144	hlist_add_head(&fq->list, &expired);
	145	++evicted;
	146	}
	147
	148	spin_unlock(&hb->chain_lock);
	149
	150	hlist_for_each_entry_safe(fq, n, &expired, list)
	151	f->frag_expire((unsigned long) fq);
	152
	153	return evicted;
	154	}
	155
	156	static void inet_frag_worker(struct work_struct *work)
	157	{
	158	unsigned int budget = INETFRAGS_EVICT_BUCKETS;
	159	unsigned int i, evicted = 0;
	160	struct inet_frags *f;
	161
	162	f = container_of(work, struct inet_frags, frags_work);
	163
	164	BUILD_BUG_ON(INETFRAGS_EVICT_BUCKETS >= INETFRAGS_HASHSZ);
	165
	166	read_lock_bh(&f->lock);
	167
	168	for (i = ACCESS_ONCE(f->next_bucket); budget; --budget) {
	169	evicted += inet_evict_bucket(f, &f->hash[i]);
170	i = (i + 1) & (INETFRAGS_HASHSZ - 1);
171	if (evicted > INETFRAGS_EVICT_MAX)
172	break;
173	}
174
175	f->next_bucket = i;
176
177	read_unlock_bh(&f->lock);
e3a57d18 FW	178	if (f->rebuild && inet_frag_may_rebuild(f))
e3a57d18 FW	179	inet_frag_secret_rebuild(f);
b13d3cbf FW	180	}
	181
	182	static void inet_frag_schedule_worker(struct inet_frags *f)
	183	{
	184	if (unlikely(!work_pending(&f->frags_work)))
	185	schedule_work(&f->frags_work);
	186	}
	187
7eb95156 PE	188	void inet_frags_init(struct inet_frags *f)
	189	{
	190	int i;
	191
b13d3cbf FW	192	INIT_WORK(&f->frags_work, inet_frag_worker);
b13d3cbf FW	193
19952cc4 JDB	194	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
19952cc4 JDB	195	struct inet_frag_bucket *hb = &f->hash[i];
7eb95156	196
19952cc4 JDB	197	spin_lock_init(&hb->chain_lock);
	198	INIT_HLIST_HEAD(&hb->chain);
	199	}
7eb95156	200	rwlock_init(&f->lock);
e3a57d18	201	f->last_rebuild_jiffies = 0;
7eb95156 PE	202	}
	203	EXPORT_SYMBOL(inet_frags_init);
	204
e5a2bb84 PE	205	void inet_frags_init_net(struct netns_frags *nf)
e5a2bb84 PE	206	{
d433673e	207	init_frag_mem_limit(nf);
e5a2bb84 PE	208	}
	209	EXPORT_SYMBOL(inet_frags_init_net);
	210
7eb95156 PE	211	void inet_frags_fini(struct inet_frags *f)
7eb95156 PE	212	{
b13d3cbf	213	cancel_work_sync(&f->frags_work);
7eb95156 PE	214	}
7eb95156 PE	215	EXPORT_SYMBOL(inet_frags_fini);
277e650d	216
81566e83 PE	217	void inet_frags_exit_net(struct netns_frags nf, struct inet_frags f)
81566e83 PE	218	{
b13d3cbf FW	219	int i;
b13d3cbf FW	220
81566e83	221	nf->low_thresh = 0;
e8e16b70	222
b13d3cbf FW	223	read_lock_bh(&f->lock);
	224
	225	for (i = 0; i < INETFRAGS_HASHSZ ; i++)
	226	inet_evict_bucket(f, &f->hash[i]);
	227
	228	read_unlock_bh(&f->lock);
6d7b857d JDB	229
6d7b857d JDB	230	percpu_counter_destroy(&nf->mem);
81566e83 PE	231	}
	232	EXPORT_SYMBOL(inet_frags_exit_net);
	233
277e650d PE	234	static inline void fq_unlink(struct inet_frag_queue fq, struct inet_frags f)
277e650d PE	235	{
19952cc4 JDB	236	struct inet_frag_bucket *hb;
	237	unsigned int hash;
	238
	239	read_lock(&f->lock);
fb3cfe6e	240	hash = inet_frag_hashfn(f, fq);
19952cc4 JDB	241	hb = &f->hash[hash];
	242
	243	spin_lock(&hb->chain_lock);
277e650d	244	hlist_del(&fq->list);
19952cc4 JDB	245	spin_unlock(&hb->chain_lock);
	246
	247	read_unlock(&f->lock);
277e650d PE	248	}
	249
	250	void inet_frag_kill(struct inet_frag_queue fq, struct inet_frags f)
	251	{
	252	if (del_timer(&fq->timer))
	253	atomic_dec(&fq->refcnt);
	254
bc578a54	255	if (!(fq->last_in & INET_FRAG_COMPLETE)) {
277e650d PE	256	fq_unlink(fq, f);
277e650d PE	257	atomic_dec(&fq->refcnt);
bc578a54	258	fq->last_in \|= INET_FRAG_COMPLETE;
277e650d PE	259	}
277e650d PE	260	}
277e650d	261	EXPORT_SYMBOL(inet_frag_kill);
1e4b8287	262
6ddc0822	263	static inline void frag_kfree_skb(struct netns_frags nf, struct inet_frags f,
d433673e	264	struct sk_buff *skb)
1e4b8287	265	{
1e4b8287 PE	266	if (f->skb_free)
	267	f->skb_free(skb);
	268	kfree_skb(skb);
	269	}
	270
3fd588eb	271	void inet_frag_destroy(struct inet_frag_queue q, struct inet_frags f)
1e4b8287 PE	272	{
1e4b8287 PE	273	struct sk_buff *fp;
6ddc0822	274	struct netns_frags *nf;
d433673e	275	unsigned int sum, sum_truesize = 0;
1e4b8287	276
547b792c IJ	277	WARN_ON(!(q->last_in & INET_FRAG_COMPLETE));
547b792c IJ	278	WARN_ON(del_timer(&q->timer) != 0);
1e4b8287 PE	279
	280	/* Release all fragment data. */
	281	fp = q->fragments;
6ddc0822	282	nf = q->net;
1e4b8287 PE	283	while (fp) {
	284	struct sk_buff *xp = fp->next;
	285
d433673e JDB	286	sum_truesize += fp->truesize;
d433673e JDB	287	frag_kfree_skb(nf, f, fp);
1e4b8287 PE	288	fp = xp;
1e4b8287 PE	289	}
d433673e	290	sum = sum_truesize + f->qsize;
d433673e	291	sub_frag_mem_limit(q, sum);
1e4b8287	292
c9547709 PE	293	if (f->destructor)
	294	f->destructor(q);
	295	kfree(q);
1e4b8287 PE	296	}
1e4b8287 PE	297	EXPORT_SYMBOL(inet_frag_destroy);
8e7999c4	298
ac18e750 PE	299	static struct inet_frag_queue inet_frag_intern(struct netns_frags nf,
ac18e750 PE	300	struct inet_frag_queue qp_in, struct inet_frags f,
9a375803	301	void *arg)
2588fe1d	302	{
19952cc4	303	struct inet_frag_bucket *hb;
2588fe1d	304	struct inet_frag_queue *qp;
9a375803	305	unsigned int hash;
2588fe1d	306
19952cc4	307	read_lock(&f->lock); /* Protects against hash rebuild */
9a375803 PE	308	/*
	309	* While we stayed w/o the lock other CPU could update
	310	* the rnd seed, so we need to re-calculate the hash
	311	* chain. Fortunatelly the qp_in can be used to get one.
	312	*/
fb3cfe6e	313	hash = inet_frag_hashfn(f, qp_in);
19952cc4 JDB	314	hb = &f->hash[hash];
	315	spin_lock(&hb->chain_lock);
	316
2588fe1d PE	317	#ifdef CONFIG_SMP
	318	/* With SMP race we have to recheck hash table, because
	319	* such entry could be created on other cpu, while we
19952cc4	320	* released the hash bucket lock.
2588fe1d	321	*/
19952cc4	322	hlist_for_each_entry(qp, &hb->chain, list) {
ac18e750	323	if (qp->net == nf && f->match(qp, arg)) {
2588fe1d	324	atomic_inc(&qp->refcnt);
19952cc4 JDB	325	spin_unlock(&hb->chain_lock);
19952cc4 JDB	326	read_unlock(&f->lock);
bc578a54	327	qp_in->last_in \|= INET_FRAG_COMPLETE;
2588fe1d PE	328	inet_frag_put(qp_in, f);
	329	return qp;
	330	}
	331	}
	332	#endif
	333	qp = qp_in;
b2fd5321	334	if (!mod_timer(&qp->timer, jiffies + nf->timeout))
2588fe1d PE	335	atomic_inc(&qp->refcnt);
	336
	337	atomic_inc(&qp->refcnt);
19952cc4	338	hlist_add_head(&qp->list, &hb->chain);
3fd588eb	339
19952cc4 JDB	340	spin_unlock(&hb->chain_lock);
19952cc4 JDB	341	read_unlock(&f->lock);
24b9bf43	342
2588fe1d PE	343	return qp;
2588fe1d PE	344	}
e521db9d	345
ac18e750 PE	346	static struct inet_frag_queue inet_frag_alloc(struct netns_frags nf,
ac18e750 PE	347	struct inet_frags f, void arg)
e521db9d PE	348	{
	349	struct inet_frag_queue *q;
	350
b13d3cbf FW	351	if (frag_mem_limit(nf) > nf->high_thresh) {
b13d3cbf FW	352	inet_frag_schedule_worker(f);
86e93e47	353	return NULL;
b13d3cbf	354	}
86e93e47	355
e521db9d PE	356	q = kzalloc(f->qsize, GFP_ATOMIC);
	357	if (q == NULL)
	358	return NULL;
	359
54db0cc2	360	q->net = nf;
c6fda282	361	f->constructor(q, arg);
d433673e JDB	362	add_frag_mem_limit(q, f->qsize);
d433673e JDB	363
e521db9d PE	364	setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
	365	spin_lock_init(&q->lock);
	366	atomic_set(&q->refcnt, 1);
	367
	368	return q;
	369	}
c6fda282	370
ac18e750	371	static struct inet_frag_queue inet_frag_create(struct netns_frags nf,
9a375803	372	struct inet_frags f, void arg)
c6fda282 PE	373	{
	374	struct inet_frag_queue *q;
	375
ac18e750	376	q = inet_frag_alloc(nf, f, arg);
c6fda282 PE	377	if (q == NULL)
	378	return NULL;
	379
9a375803	380	return inet_frag_intern(nf, q, f, arg);
c6fda282	381	}
abd6523d	382
ac18e750 PE	383	struct inet_frag_queue inet_frag_find(struct netns_frags nf,
ac18e750 PE	384	struct inet_frags f, void key, unsigned int hash)
56bca31f	385	__releases(&f->lock)
abd6523d	386	{
19952cc4	387	struct inet_frag_bucket *hb;
abd6523d	388	struct inet_frag_queue *q;
5a3da1fe	389	int depth = 0;
abd6523d	390
b13d3cbf FW	391	if (frag_mem_limit(nf) > nf->low_thresh)
b13d3cbf FW	392	inet_frag_schedule_worker(f);
86e93e47	393
fb3cfe6e	394	hash &= (INETFRAGS_HASHSZ - 1);
19952cc4 JDB	395	hb = &f->hash[hash];
	396
	397	spin_lock(&hb->chain_lock);
	398	hlist_for_each_entry(q, &hb->chain, list) {
ac18e750	399	if (q->net == nf && f->match(q, key)) {
abd6523d	400	atomic_inc(&q->refcnt);
19952cc4	401	spin_unlock(&hb->chain_lock);
abd6523d PE	402	read_unlock(&f->lock);
	403	return q;
	404	}
5a3da1fe	405	depth++;
abd6523d	406	}
19952cc4	407	spin_unlock(&hb->chain_lock);
abd6523d PE	408	read_unlock(&f->lock);
abd6523d PE	409
5a3da1fe HFS	410	if (depth <= INETFRAGS_MAXDEPTH)
5a3da1fe HFS	411	return inet_frag_create(nf, f, key);
e3a57d18 FW	412
	413	if (inet_frag_may_rebuild(f)) {
	414	f->rebuild = true;
	415	inet_frag_schedule_worker(f);
	416	}
	417
	418	return ERR_PTR(-ENOBUFS);
abd6523d PE	419	}
abd6523d PE	420	EXPORT_SYMBOL(inet_frag_find);
5a3da1fe HFS	421
	422	void inet_frag_maybe_warn_overflow(struct inet_frag_queue *q,
	423	const char *prefix)
	424	{
	425	static const char msg[] = "inet_frag_find: Fragment hash bucket"
	426	" list length grew over limit " __stringify(INETFRAGS_MAXDEPTH)
	427	". Dropping fragment.\n";
	428
	429	if (PTR_ERR(q) == -ENOBUFS)
	430	LIMIT_NETDEBUG(KERN_WARNING "%s%s", prefix, msg);
	431	}
	432	EXPORT_SYMBOL(inet_frag_maybe_warn_overflow);