ipvs: convert lblc scheduler to rcu
[linux-3.10.git] / net / netfilter / xt_quota.c
1 /*
2  * netfilter module to enforce network quotas
3  *
4  * Sam Johnston <samj@samj.net>
5  */
6 #include <linux/skbuff.h>
7 #include <linux/slab.h>
8 #include <linux/spinlock.h>
9
10 #include <linux/netfilter/x_tables.h>
11 #include <linux/netfilter/xt_quota.h>
12 #include <linux/module.h>
13
14 struct xt_quota_priv {
15         spinlock_t      lock;
16         uint64_t        quota;
17 };
18
19 MODULE_LICENSE("GPL");
20 MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
21 MODULE_DESCRIPTION("Xtables: countdown quota match");
22 MODULE_ALIAS("ipt_quota");
23 MODULE_ALIAS("ip6t_quota");
24
25 static bool
26 quota_mt(const struct sk_buff *skb, struct xt_action_param *par)
27 {
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;
31
32         spin_lock_bh(&priv->lock);
33         if (priv->quota >= skb->len) {
34                 priv->quota -= skb->len;
35                 ret = !ret;
36         } else {
37                 /* we do not allow even small packets from now on */
38                 priv->quota = 0;
39         }
40         spin_unlock_bh(&priv->lock);
41
42         return ret;
43 }
44
45 static int quota_mt_check(const struct xt_mtchk_param *par)
46 {
47         struct xt_quota_info *q = par->matchinfo;
48
49         if (q->flags & ~XT_QUOTA_MASK)
50                 return -EINVAL;
51
52         q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
53         if (q->master == NULL)
54                 return -ENOMEM;
55
56         spin_lock_init(&q->master->lock);
57         q->master->quota = q->quota;
58         return 0;
59 }
60
61 static void quota_mt_destroy(const struct xt_mtdtor_param *par)
62 {
63         const struct xt_quota_info *q = par->matchinfo;
64
65         kfree(q->master);
66 }
67
68 static struct xt_match quota_mt_reg __read_mostly = {
69         .name       = "quota",
70         .revision   = 0,
71         .family     = NFPROTO_UNSPEC,
72         .match      = quota_mt,
73         .checkentry = quota_mt_check,
74         .destroy    = quota_mt_destroy,
75         .matchsize  = sizeof(struct xt_quota_info),
76         .me         = THIS_MODULE,
77 };
78
79 static int __init quota_mt_init(void)
80 {
81         return xt_register_match(&quota_mt_reg);
82 }
83
84 static void __exit quota_mt_exit(void)
85 {
86         xt_unregister_match(&quota_mt_reg);
87 }
88
89 module_init(quota_mt_init);
90 module_exit(quota_mt_exit);