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Commit | Line | Data |
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62b77434 PM |
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 | ||
acc738fe JE |
12 | struct xt_quota_priv { |
13 | uint64_t quota; | |
14 | }; | |
15 | ||
62b77434 PM |
16 | MODULE_LICENSE("GPL"); |
17 | MODULE_AUTHOR("Sam Johnston <samj@samj.net>"); | |
2ae15b64 | 18 | MODULE_DESCRIPTION("Xtables: countdown quota match"); |
b22b9004 PM |
19 | MODULE_ALIAS("ipt_quota"); |
20 | MODULE_ALIAS("ip6t_quota"); | |
62b77434 PM |
21 | |
22 | static DEFINE_SPINLOCK(quota_lock); | |
23 | ||
1d93a9cb | 24 | static bool |
f7108a20 | 25 | quota_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
62b77434 | 26 | { |
acc738fe JE |
27 | struct xt_quota_info *q = (void *)par->matchinfo; |
28 | struct xt_quota_priv *priv = q->master; | |
1d93a9cb | 29 | bool ret = q->flags & XT_QUOTA_INVERT; |
62b77434 PM |
30 | |
31 | spin_lock_bh("a_lock); | |
acc738fe JE |
32 | if (priv->quota >= skb->len) { |
33 | priv->quota -= skb->len; | |
1d93a9cb | 34 | ret = !ret; |
62b77434 | 35 | } else { |
601e68e1 | 36 | /* we do not allow even small packets from now on */ |
acc738fe | 37 | priv->quota = 0; |
62b77434 | 38 | } |
acc738fe JE |
39 | /* Copy quota back to matchinfo so that iptables can display it */ |
40 | q->quota = priv->quota; | |
62b77434 PM |
41 | spin_unlock_bh("a_lock); |
42 | ||
43 | return ret; | |
44 | } | |
45 | ||
9b4fce7a | 46 | static bool quota_mt_check(const struct xt_mtchk_param *par) |
62b77434 | 47 | { |
9b4fce7a | 48 | struct xt_quota_info *q = par->matchinfo; |
62b77434 PM |
49 | |
50 | if (q->flags & ~XT_QUOTA_MASK) | |
ccb79bdc | 51 | return false; |
acc738fe JE |
52 | |
53 | q->master = kmalloc(sizeof(*q->master), GFP_KERNEL); | |
54 | if (q->master == NULL) | |
2149f66f | 55 | return false; |
acc738fe | 56 | |
6d62182f | 57 | q->master->quota = q->quota; |
ccb79bdc | 58 | return true; |
62b77434 PM |
59 | } |
60 | ||
acc738fe JE |
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 | ||
55b69e91 JE |
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, | |
acc738fe | 74 | .destroy = quota_mt_destroy, |
55b69e91 JE |
75 | .matchsize = sizeof(struct xt_quota_info), |
76 | .me = THIS_MODULE, | |
62b77434 PM |
77 | }; |
78 | ||
d3c5ee6d | 79 | static int __init quota_mt_init(void) |
62b77434 | 80 | { |
55b69e91 | 81 | return xt_register_match("a_mt_reg); |
62b77434 PM |
82 | } |
83 | ||
d3c5ee6d | 84 | static void __exit quota_mt_exit(void) |
62b77434 | 85 | { |
55b69e91 | 86 | xt_unregister_match("a_mt_reg); |
62b77434 PM |
87 | } |
88 | ||
d3c5ee6d JE |
89 | module_init(quota_mt_init); |
90 | module_exit(quota_mt_exit); |