diff options
Diffstat (limited to 'net/ipv4/inet_fragment.c')
| -rw-r--r-- | net/ipv4/inet_fragment.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c new file mode 100644 index 00000000000..484cf512858 --- /dev/null +++ b/net/ipv4/inet_fragment.c @@ -0,0 +1,174 @@ +/* + * 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 <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); + +static inline void frag_kfree_skb(struct inet_frags *f, struct sk_buff *skb, + int *work) +{ + if (work) + *work -= skb->truesize; + + atomic_sub(skb->truesize, &f->mem); + 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; + + BUG_TRAP(q->last_in & COMPLETE); + BUG_TRAP(del_timer(&q->timer) == 0); + + /* Release all fragment data. */ + fp = q->fragments; + while (fp) { + struct sk_buff *xp = fp->next; + + frag_kfree_skb(f, fp, work); + fp = xp; + } + + if (work) + *work -= f->qsize; + atomic_sub(f->qsize, &f->mem); + + f->destructor(q); + +} +EXPORT_SYMBOL(inet_frag_destroy); + +int inet_frag_evictor(struct inet_frags *f) +{ + struct inet_frag_queue *q; + int work, evicted = 0; + + work = atomic_read(&f->mem) - f->ctl->low_thresh; + while (work > 0) { + read_lock(&f->lock); + if (list_empty(&f->lru_list)) { + read_unlock(&f->lock); + break; + } + + q = list_first_entry(&f->lru_list, + struct inet_frag_queue, lru_list); + atomic_inc(&q->refcnt); + read_unlock(&f->lock); + + spin_lock(&q->lock); + if (!(q->last_in & 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); |