[NETFILTER]: nf_conntrack: use extension infrastructure for helper
[linux-2.6] / 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 MODULE_LICENSE("GPL");
13 MODULE_AUTHOR("Sam Johnston <samj@samj.net>");
14 MODULE_ALIAS("ipt_quota");
15 MODULE_ALIAS("ip6t_quota");
16
17 static DEFINE_SPINLOCK(quota_lock);
18
19 static bool
20 match(const struct sk_buff *skb,
21       const struct net_device *in, const struct net_device *out,
22       const struct xt_match *match, const void *matchinfo,
23       int offset, unsigned int protoff, bool *hotdrop)
24 {
25         struct xt_quota_info *q =
26                 ((const struct xt_quota_info *)matchinfo)->master;
27         bool ret = q->flags & XT_QUOTA_INVERT;
28
29         spin_lock_bh(&quota_lock);
30         if (q->quota >= skb->len) {
31                 q->quota -= skb->len;
32                 ret = !ret;
33         } else {
34                 /* we do not allow even small packets from now on */
35                 q->quota = 0;
36         }
37         spin_unlock_bh(&quota_lock);
38
39         return ret;
40 }
41
42 static bool
43 checkentry(const char *tablename, const void *entry,
44            const struct xt_match *match, void *matchinfo,
45            unsigned int hook_mask)
46 {
47         struct xt_quota_info *q = matchinfo;
48
49         if (q->flags & ~XT_QUOTA_MASK)
50                 return false;
51         /* For SMP, we only want to use one set of counters. */
52         q->master = q;
53         return true;
54 }
55
56 static struct xt_match xt_quota_match[] __read_mostly = {
57         {
58                 .name           = "quota",
59                 .family         = AF_INET,
60                 .checkentry     = checkentry,
61                 .match          = match,
62                 .matchsize      = sizeof(struct xt_quota_info),
63                 .me             = THIS_MODULE
64         },
65         {
66                 .name           = "quota",
67                 .family         = AF_INET6,
68                 .checkentry     = checkentry,
69                 .match          = match,
70                 .matchsize      = sizeof(struct xt_quota_info),
71                 .me             = THIS_MODULE
72         },
73 };
74
75 static int __init xt_quota_init(void)
76 {
77         return xt_register_matches(xt_quota_match, ARRAY_SIZE(xt_quota_match));
78 }
79
80 static void __exit xt_quota_fini(void)
81 {
82         xt_unregister_matches(xt_quota_match, ARRAY_SIZE(xt_quota_match));
83 }
84
85 module_init(xt_quota_init);
86 module_exit(xt_quota_fini);