2007-10-15 02:31:52 -07:00
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/*
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* inet fragments management
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Pavel Emelyanov <xemul@openvz.org>
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* Started as consolidation of ipv4/ip_fragment.c,
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* ipv6/reassembly. and ipv6 nf conntrack reassembly
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*/
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#include <linux/list.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/mm.h>
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2007-10-15 02:38:08 -07:00
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#include <linux/random.h>
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2007-10-15 02:39:14 -07:00
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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2007-10-15 02:31:52 -07:00
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#include <net/inet_frag.h>
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2007-10-15 02:38:08 -07:00
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static void inet_frag_secret_rebuild(unsigned long dummy)
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{
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struct inet_frags *f = (struct inet_frags *)dummy;
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unsigned long now = jiffies;
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int i;
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write_lock(&f->lock);
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get_random_bytes(&f->rnd, sizeof(u32));
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for (i = 0; i < INETFRAGS_HASHSZ; i++) {
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struct inet_frag_queue *q;
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struct hlist_node *p, *n;
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hlist_for_each_entry_safe(q, p, n, &f->hash[i], list) {
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unsigned int hval = f->hashfn(q);
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if (hval != i) {
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hlist_del(&q->list);
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/* Relink to new hash chain. */
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hlist_add_head(&q->list, &f->hash[hval]);
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}
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}
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}
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write_unlock(&f->lock);
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mod_timer(&f->secret_timer, now + f->ctl->secret_interval);
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}
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2007-10-15 02:31:52 -07:00
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void inet_frags_init(struct inet_frags *f)
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{
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int i;
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for (i = 0; i < INETFRAGS_HASHSZ; i++)
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INIT_HLIST_HEAD(&f->hash[i]);
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INIT_LIST_HEAD(&f->lru_list);
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rwlock_init(&f->lock);
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f->rnd = (u32) ((num_physpages ^ (num_physpages>>7)) ^
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(jiffies ^ (jiffies >> 6)));
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f->nqueues = 0;
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atomic_set(&f->mem, 0);
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2007-10-15 02:38:08 -07:00
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init_timer(&f->secret_timer);
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f->secret_timer.function = inet_frag_secret_rebuild;
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f->secret_timer.data = (unsigned long)f;
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f->secret_timer.expires = jiffies + f->ctl->secret_interval;
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add_timer(&f->secret_timer);
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2007-10-15 02:31:52 -07:00
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}
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EXPORT_SYMBOL(inet_frags_init);
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void inet_frags_fini(struct inet_frags *f)
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{
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2007-10-15 02:38:08 -07:00
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del_timer(&f->secret_timer);
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2007-10-15 02:31:52 -07:00
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}
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EXPORT_SYMBOL(inet_frags_fini);
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2007-10-15 02:37:18 -07:00
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static inline void fq_unlink(struct inet_frag_queue *fq, struct inet_frags *f)
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{
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write_lock(&f->lock);
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hlist_del(&fq->list);
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list_del(&fq->lru_list);
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f->nqueues--;
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write_unlock(&f->lock);
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}
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void inet_frag_kill(struct inet_frag_queue *fq, struct inet_frags *f)
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{
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if (del_timer(&fq->timer))
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atomic_dec(&fq->refcnt);
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if (!(fq->last_in & COMPLETE)) {
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fq_unlink(fq, f);
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atomic_dec(&fq->refcnt);
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fq->last_in |= COMPLETE;
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}
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}
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EXPORT_SYMBOL(inet_frag_kill);
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2007-10-15 02:39:14 -07:00
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static inline void frag_kfree_skb(struct inet_frags *f, struct sk_buff *skb,
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int *work)
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{
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if (work)
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*work -= skb->truesize;
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atomic_sub(skb->truesize, &f->mem);
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if (f->skb_free)
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f->skb_free(skb);
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kfree_skb(skb);
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}
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void inet_frag_destroy(struct inet_frag_queue *q, struct inet_frags *f,
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int *work)
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{
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struct sk_buff *fp;
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BUG_TRAP(q->last_in & COMPLETE);
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BUG_TRAP(del_timer(&q->timer) == 0);
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/* Release all fragment data. */
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fp = q->fragments;
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while (fp) {
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struct sk_buff *xp = fp->next;
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frag_kfree_skb(f, fp, work);
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fp = xp;
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}
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if (work)
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*work -= f->qsize;
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atomic_sub(f->qsize, &f->mem);
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f->destructor(q);
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}
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EXPORT_SYMBOL(inet_frag_destroy);
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2007-10-15 02:40:06 -07:00
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int inet_frag_evictor(struct inet_frags *f)
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{
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struct inet_frag_queue *q;
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int work, evicted = 0;
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work = atomic_read(&f->mem) - f->ctl->low_thresh;
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while (work > 0) {
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read_lock(&f->lock);
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if (list_empty(&f->lru_list)) {
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read_unlock(&f->lock);
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break;
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}
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q = list_first_entry(&f->lru_list,
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struct inet_frag_queue, lru_list);
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atomic_inc(&q->refcnt);
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read_unlock(&f->lock);
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spin_lock(&q->lock);
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if (!(q->last_in & COMPLETE))
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inet_frag_kill(q, f);
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spin_unlock(&q->lock);
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if (atomic_dec_and_test(&q->refcnt))
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inet_frag_destroy(q, f, &work);
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evicted++;
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}
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return evicted;
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}
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EXPORT_SYMBOL(inet_frag_evictor);
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2007-10-17 19:44:34 -07:00
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2007-10-17 19:46:47 -07:00
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static struct inet_frag_queue *inet_frag_intern(struct inet_frag_queue *qp_in,
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2007-10-17 19:44:34 -07:00
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struct inet_frags *f, unsigned int hash)
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{
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struct inet_frag_queue *qp;
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#ifdef CONFIG_SMP
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struct hlist_node *n;
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#endif
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write_lock(&f->lock);
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#ifdef CONFIG_SMP
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/* With SMP race we have to recheck hash table, because
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* such entry could be created on other cpu, while we
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* promoted read lock to write lock.
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*/
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hlist_for_each_entry(qp, n, &f->hash[hash], list) {
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if (f->equal(qp, qp_in)) {
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atomic_inc(&qp->refcnt);
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write_unlock(&f->lock);
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qp_in->last_in |= COMPLETE;
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inet_frag_put(qp_in, f);
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return qp;
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}
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}
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#endif
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qp = qp_in;
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if (!mod_timer(&qp->timer, jiffies + f->ctl->timeout))
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atomic_inc(&qp->refcnt);
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atomic_inc(&qp->refcnt);
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hlist_add_head(&qp->list, &f->hash[hash]);
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list_add_tail(&qp->lru_list, &f->lru_list);
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f->nqueues++;
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write_unlock(&f->lock);
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return qp;
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}
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2007-10-17 19:45:23 -07:00
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2007-10-17 19:46:47 -07:00
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static struct inet_frag_queue *inet_frag_alloc(struct inet_frags *f, void *arg)
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2007-10-17 19:45:23 -07:00
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{
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struct inet_frag_queue *q;
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q = kzalloc(f->qsize, GFP_ATOMIC);
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if (q == NULL)
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return NULL;
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2007-10-17 19:46:47 -07:00
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f->constructor(q, arg);
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2007-10-17 19:45:23 -07:00
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atomic_add(f->qsize, &f->mem);
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setup_timer(&q->timer, f->frag_expire, (unsigned long)q);
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spin_lock_init(&q->lock);
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atomic_set(&q->refcnt, 1);
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return q;
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}
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2007-10-17 19:46:47 -07:00
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struct inet_frag_queue *inet_frag_create(struct inet_frags *f, void *arg,
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unsigned int hash)
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{
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struct inet_frag_queue *q;
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q = inet_frag_alloc(f, arg);
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if (q == NULL)
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return NULL;
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return inet_frag_intern(q, f, hash);
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}
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EXPORT_SYMBOL(inet_frag_create);
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