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- /*
- * netfilter module to enforce network quotas
- *
- * Sam Johnston <samj@samj.net>
- */
- #include <linux/skbuff.h>
- #include <linux/spinlock.h>
- #include <linux/netfilter/x_tables.h>
- #include <linux/netfilter/xt_quota.h>
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
- MODULE_ALIAS("ipt_quota");
- MODULE_ALIAS("ip6t_quota");
- static DEFINE_SPINLOCK(quota_lock);
- static int
- match(const struct sk_buff *skb,
- const struct net_device *in, const struct net_device *out,
- const struct xt_match *match, const void *matchinfo,
- int offset, unsigned int protoff, int *hotdrop)
- {
- struct xt_quota_info *q = ((struct xt_quota_info *)matchinfo)->master;
- int ret = q->flags & XT_QUOTA_INVERT ? 1 : 0;
- spin_lock_bh("a_lock);
- if (q->quota >= skb->len) {
- q->quota -= skb->len;
- ret ^= 1;
- } else {
- /* we do not allow even small packets from now on */
- q->quota = 0;
- }
- spin_unlock_bh("a_lock);
- return ret;
- }
- static int
- checkentry(const char *tablename, const void *entry,
- const struct xt_match *match, void *matchinfo,
- unsigned int hook_mask)
- {
- struct xt_quota_info *q = (struct xt_quota_info *)matchinfo;
- if (q->flags & ~XT_QUOTA_MASK)
- return 0;
- /* For SMP, we only want to use one set of counters. */
- q->master = q;
- return 1;
- }
- static struct xt_match xt_quota_match[] = {
- {
- .name = "quota",
- .family = AF_INET,
- .checkentry = checkentry,
- .match = match,
- .matchsize = sizeof(struct xt_quota_info),
- .me = THIS_MODULE
- },
- {
- .name = "quota",
- .family = AF_INET6,
- .checkentry = checkentry,
- .match = match,
- .matchsize = sizeof(struct xt_quota_info),
- .me = THIS_MODULE
- },
- };
- static int __init xt_quota_init(void)
- {
- return xt_register_matches(xt_quota_match, ARRAY_SIZE(xt_quota_match));
- }
- static void __exit xt_quota_fini(void)
- {
- xt_unregister_matches(xt_quota_match, ARRAY_SIZE(xt_quota_match));
- }
- module_init(xt_quota_init);
- module_exit(xt_quota_fini);
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