[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 <net/inet_frag.h>

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 *p, *n;

		hlist_for_each_entry_safe(q, p, 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->ctl->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]);

	INIT_LIST_HEAD(&f->lru_list);
	rwlock_init(&f->lock);

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

	f->nqueues = 0;
	atomic_set(&f->mem, 0);

	init_timer(&f->secret_timer);
	f->secret_timer.function = inet_frag_secret_rebuild;
	f->secret_timer.data = (unsigned long)f;
	f->secret_timer.expires = jiffies + f->ctl->secret_interval;
	add_timer(&f->secret_timer);
}
EXPORT_SYMBOL(inet_frags_init);

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

static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
{
	write_lock(&f->lock);
	hlist_del(&fq->list);
	list_del(&fq->lru_list);
	f->nqueues--;
	write_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 & COMPLETE)) {
		fq_unlink(fq, f);
		atomic_dec(&fq->refcnt);
		fq->last_in |= COMPLETE;
	}
}

EXPORT_SYMBOL(inet_frag_kill);
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>
7eb95156 PE	20
	21	#include <net/inet_frag.h>
	22
321a3a99 PE	23	static void inet_frag_secret_rebuild(unsigned long dummy)
	24	{
	25	struct inet_frags f = (struct inet_frags )dummy;
	26	unsigned long now = jiffies;
	27	int i;
	28
	29	write_lock(&f->lock);
	30	get_random_bytes(&f->rnd, sizeof(u32));
	31	for (i = 0; i < INETFRAGS_HASHSZ; i++) {
	32	struct inet_frag_queue *q;
	33	struct hlist_node p, n;
	34
	35	hlist_for_each_entry_safe(q, p, n, &f->hash[i], list) {
	36	unsigned int hval = f->hashfn(q);
	37
	38	if (hval != i) {
	39	hlist_del(&q->list);
	40
	41	/* Relink to new hash chain. */
	42	hlist_add_head(&q->list, &f->hash[hval]);
	43	}
	44	}
	45	}
	46	write_unlock(&f->lock);
	47
	48	mod_timer(&f->secret_timer, now + f->ctl->secret_interval);
	49	}
	50
7eb95156 PE	51	void inet_frags_init(struct inet_frags *f)
	52	{
	53	int i;
	54
	55	for (i = 0; i < INETFRAGS_HASHSZ; i++)
	56	INIT_HLIST_HEAD(&f->hash[i]);
	57
	58	INIT_LIST_HEAD(&f->lru_list);
	59	rwlock_init(&f->lock);
	60
	61	f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
	62	(jiffies ^ (jiffies >> 6)));
	63
	64	f->nqueues = 0;
	65	atomic_set(&f->mem, 0);
	66
321a3a99 PE	67	init_timer(&f->secret_timer);
	68	f->secret_timer.function = inet_frag_secret_rebuild;
	69	f->secret_timer.data = (unsigned long)f;
	70	f->secret_timer.expires = jiffies + f->ctl->secret_interval;
	71	add_timer(&f->secret_timer);
7eb95156 PE	72	}
	73	EXPORT_SYMBOL(inet_frags_init);
	74
	75	void inet_frags_fini(struct inet_frags *f)
	76	{
321a3a99	77	del_timer(&f->secret_timer);
7eb95156 PE	78	}
7eb95156 PE	79	EXPORT_SYMBOL(inet_frags_fini);
277e650d PE	80
	81	static inline void fq_unlink(struct inet_frag_queue fq, struct inet_frags f)
	82	{
	83	write_lock(&f->lock);
	84	hlist_del(&fq->list);
	85	list_del(&fq->lru_list);
	86	f->nqueues--;
	87	write_unlock(&f->lock);
	88	}
	89
	90	void inet_frag_kill(struct inet_frag_queue fq, struct inet_frags f)
	91	{
	92	if (del_timer(&fq->timer))
	93	atomic_dec(&fq->refcnt);
	94
	95	if (!(fq->last_in & COMPLETE)) {
	96	fq_unlink(fq, f);
	97	atomic_dec(&fq->refcnt);
	98	fq->last_in \|= COMPLETE;
	99	}
	100	}
	101
	102	EXPORT_SYMBOL(inet_frag_kill);