2 * netfilter module to enforce network quotas
4 * Sam Johnston <samj@samj.net>
6 #include <linux/skbuff.h>
7 #include <linux/slab.h>
8 #include <linux/spinlock.h>
10 #include <linux/netfilter/x_tables.h>
11 #include <linux/netfilter/xt_quota.h>
13 struct xt_quota_priv {
18 MODULE_LICENSE("GPL");
19 MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
20 MODULE_DESCRIPTION("Xtables: countdown quota match");
21 MODULE_ALIAS("ipt_quota");
22 MODULE_ALIAS("ip6t_quota");
25 quota_mt(const struct sk_buff *skb, struct xt_action_param *par)
27 struct xt_quota_info *q = (void *)par->matchinfo;
28 struct xt_quota_priv *priv = q->master;
29 bool ret = q->flags & XT_QUOTA_INVERT;
31 spin_lock_bh(&priv->lock);
32 if (priv->quota >= skb->len) {
33 priv->quota -= skb->len;
36 /* we do not allow even small packets from now on */
39 spin_unlock_bh(&priv->lock);
44 static int quota_mt_check(const struct xt_mtchk_param *par)
46 struct xt_quota_info *q = par->matchinfo;
48 if (q->flags & ~XT_QUOTA_MASK)
51 q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
52 if (q->master == NULL)
55 spin_lock_init(&q->master->lock);
56 q->master->quota = q->quota;
60 static void quota_mt_destroy(const struct xt_mtdtor_param *par)
62 const struct xt_quota_info *q = par->matchinfo;
67 static struct xt_match quota_mt_reg __read_mostly = {
70 .family = NFPROTO_UNSPEC,
72 .checkentry = quota_mt_check,
73 .destroy = quota_mt_destroy,
74 .matchsize = sizeof(struct xt_quota_info),
78 static int __init quota_mt_init(void)
80 return xt_register_match("a_mt_reg);
83 static void __exit quota_mt_exit(void)
85 xt_unregister_match("a_mt_reg);
88 module_init(quota_mt_init);
89 module_exit(quota_mt_exit);