[NET] ATM: Use htons() where appropriate.
[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 int
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, int *hotdrop)
24 {
25         struct xt_quota_info *q = ((struct xt_quota_info *)matchinfo)->master;
26         int ret = q->flags & XT_QUOTA_INVERT ? 1 : 0;
27
28         spin_lock_bh(&quota_lock);
29         if (q->quota >= skb->len) {
30                 q->quota -= skb->len;
31                 ret ^= 1;
32         } else {
33                 /* we do not allow even small packets from now on */
34                 q->quota = 0;
35         }
36         spin_unlock_bh(&quota_lock);
37
38         return ret;
39 }
40
41 static int
42 checkentry(const char *tablename, const void *entry,
43            const struct xt_match *match, void *matchinfo,
44            unsigned int hook_mask)
45 {
46         struct xt_quota_info *q = (struct xt_quota_info *)matchinfo;
47
48         if (q->flags & ~XT_QUOTA_MASK)
49                 return 0;
50         /* For SMP, we only want to use one set of counters. */
51         q->master = q;
52         return 1;
53 }
54
55 static struct xt_match xt_quota_match[] = {
56         {
57                 .name           = "quota",
58                 .family         = AF_INET,
59                 .checkentry     = checkentry,
60                 .match          = match,
61                 .matchsize      = sizeof(struct xt_quota_info),
62                 .me             = THIS_MODULE
63         },
64         {
65                 .name           = "quota",
66                 .family         = AF_INET6,
67                 .checkentry     = checkentry,
68                 .match          = match,
69                 .matchsize      = sizeof(struct xt_quota_info),
70                 .me             = THIS_MODULE
71         },
72 };
73
74 static int __init xt_quota_init(void)
75 {
76         return xt_register_matches(xt_quota_match, ARRAY_SIZE(xt_quota_match));
77 }
78
79 static void __exit xt_quota_fini(void)
80 {
81         xt_unregister_matches(xt_quota_match, ARRAY_SIZE(xt_quota_match));
82 }
83
84 module_init(xt_quota_init);
85 module_exit(xt_quota_fini);