netfilter: xtables: change xt_match.checkentry return type
[linux-2.6.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/spinlock.h>
8
9 #include <linux/netfilter/x_tables.h>
10 #include <linux/netfilter/xt_quota.h>
11
12 struct xt_quota_priv {
13         uint64_t quota;
14 };
15
16 MODULE_LICENSE("GPL");
17 MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
18 MODULE_DESCRIPTION("Xtables: countdown quota match");
19 MODULE_ALIAS("ipt_quota");
20 MODULE_ALIAS("ip6t_quota");
21
22 static DEFINE_SPINLOCK(quota_lock);
23
24 static bool
25 quota_mt(const struct sk_buff *skb, const struct xt_match_param *par)
26 {
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;
30
31         spin_lock_bh(&quota_lock);
32         if (priv->quota >= skb->len) {
33                 priv->quota -= skb->len;
34                 ret = !ret;
35         } else {
36                 /* we do not allow even small packets from now on */
37                 priv->quota = 0;
38         }
39         /* Copy quota back to matchinfo so that iptables can display it */
40         q->quota = priv->quota;
41         spin_unlock_bh(&quota_lock);
42
43         return ret;
44 }
45
46 static int quota_mt_check(const struct xt_mtchk_param *par)
47 {
48         struct xt_quota_info *q = par->matchinfo;
49
50         if (q->flags & ~XT_QUOTA_MASK)
51                 return false;
52
53         q->master = kmalloc(sizeof(*q->master), GFP_KERNEL);
54         if (q->master == NULL)
55                 return false;
56
57         q->master->quota = q->quota;
58         return true;
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);