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/*
* netfilter module to enforce network quotas
*
* Sam Johnston <samj@samj.net>
*
* 30/01/05: Fixed on SMP --Pablo Neira <pablo@eurodev.net>
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_quota.h>
MODULE_LICENSE("GPL");
static spinlock_t quota_lock = SPIN_LOCK_UNLOCKED;
static int
match(const struct sk_buff *skb,
const struct net_device *in,
const struct net_device *out,
const void *matchinfo,
int offset, const void *hdr, u_int16_t datalen, int *hotdrop)
{
struct ipt_quota_info *q =
((struct ipt_quota_info *) matchinfo)->master;
spin_lock_bh("a_lock);
if (q->quota >= datalen) {
/* we can afford this one */
q->quota -= datalen;
spin_unlock_bh("a_lock);
#ifdef DEBUG_IPT_QUOTA
printk("IPT Quota OK: %llu datlen %d \n", q->quota, datalen);
#endif
return 1;
}
/* so we do not allow even small packets from now on */
q->quota = 0;
#ifdef DEBUG_IPT_QUOTA
printk("IPT Quota Failed: %llu datlen %d \n", q->quota, datalen);
#endif
spin_unlock_bh("a_lock);
return 0;
}
static int
checkentry(const char *tablename,
const struct ipt_ip *ip,
void *matchinfo, unsigned int matchsize, unsigned int hook_mask)
{
/* TODO: spinlocks? sanity checks? */
struct ipt_quota_info *q = (struct ipt_quota_info *) matchinfo;
if (matchsize != IPT_ALIGN(sizeof (struct ipt_quota_info)))
return 0;
/* For SMP, we only want to use one set of counters. */
q->master = q;
return 1;
}
static struct ipt_match quota_match
= { {NULL, NULL}, "quota", &match, &checkentry, NULL, THIS_MODULE };
static int __init
init(void)
{
return ipt_register_match("a_match);
}
static void __exit
fini(void)
{
ipt_unregister_match("a_match);
}
module_init(init);
module_exit(fini);
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