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 {
17 MODULE_LICENSE("GPL");
18 MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
19 MODULE_DESCRIPTION("Xtables: countdown quota match");
20 MODULE_ALIAS("ipt_quota");
21 MODULE_ALIAS("ip6t_quota");
23 static DEFINE_SPINLOCK(quota_lock);
26 quota_mt(const struct sk_buff *skb, const struct xt_match_param *par)
28 struct xt_quota_info *q = (void *)par->matchinfo;
29 struct xt_quota_priv *priv = q->master;
30 bool ret = q->flags & XT_QUOTA_INVERT;
32 spin_lock_bh("a_lock);
33 if (priv->quota >= skb->len) {
34 priv->quota -= skb->len;
37 /* we do not allow even small packets from now on */
40 /* Copy quota back to matchinfo so that iptables can display it */
41 q->quota = priv->quota;
42 spin_unlock_bh("a_lock);
47 static bool quota_mt_check(const struct xt_mtchk_param *par)
49 struct xt_quota_info *q = par->matchinfo;
51 if (q->flags & ~XT_QUOTA_MASK)
54 q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
55 if (q->master == NULL)
58 q->master->quota = q->quota;
62 static void quota_mt_destroy(const struct xt_mtdtor_param *par)
64 const struct xt_quota_info *q = par->matchinfo;
69 static struct xt_match quota_mt_reg __read_mostly = {
72 .family = NFPROTO_UNSPEC,
74 .checkentry = quota_mt_check,
75 .destroy = quota_mt_destroy,
76 .matchsize = sizeof(struct xt_quota_info),
80 static int __init quota_mt_init(void)
82 return xt_register_match("a_mt_reg);
85 static void __exit quota_mt_exit(void)
87 xt_unregister_match("a_mt_reg);
90 module_init(quota_mt_init);
91 module_exit(quota_mt_exit);