Commit | Line | Data |
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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
62b77434 PM |
2 | /* |
3 | * netfilter module to enforce network quotas | |
4 | * | |
5 | * Sam Johnston <samj@samj.net> | |
6 | */ | |
7 | #include <linux/skbuff.h> | |
5a0e3ad6 | 8 | #include <linux/slab.h> |
62b77434 PM |
9 | #include <linux/spinlock.h> |
10 | ||
11 | #include <linux/netfilter/x_tables.h> | |
12 | #include <linux/netfilter/xt_quota.h> | |
3a9a231d | 13 | #include <linux/module.h> |
62b77434 | 14 | |
acc738fe | 15 | struct xt_quota_priv { |
b0c81aa5 CG |
16 | spinlock_t lock; |
17 | uint64_t quota; | |
acc738fe JE |
18 | }; |
19 | ||
62b77434 PM |
20 | MODULE_LICENSE("GPL"); |
21 | MODULE_AUTHOR("Sam Johnston <samj@samj.net>"); | |
2ae15b64 | 22 | MODULE_DESCRIPTION("Xtables: countdown quota match"); |
b22b9004 PM |
23 | MODULE_ALIAS("ipt_quota"); |
24 | MODULE_ALIAS("ip6t_quota"); | |
62b77434 | 25 | |
1d93a9cb | 26 | static bool |
62fc8051 | 27 | quota_mt(const struct sk_buff *skb, struct xt_action_param *par) |
62b77434 | 28 | { |
acc738fe JE |
29 | struct xt_quota_info *q = (void *)par->matchinfo; |
30 | struct xt_quota_priv *priv = q->master; | |
1d93a9cb | 31 | bool ret = q->flags & XT_QUOTA_INVERT; |
62b77434 | 32 | |
b0c81aa5 | 33 | spin_lock_bh(&priv->lock); |
acc738fe JE |
34 | if (priv->quota >= skb->len) { |
35 | priv->quota -= skb->len; | |
1d93a9cb | 36 | ret = !ret; |
62b77434 | 37 | } else { |
601e68e1 | 38 | /* we do not allow even small packets from now on */ |
acc738fe | 39 | priv->quota = 0; |
62b77434 | 40 | } |
b0c81aa5 | 41 | spin_unlock_bh(&priv->lock); |
62b77434 PM |
42 | |
43 | return ret; | |
44 | } | |
45 | ||
b0f38452 | 46 | static int 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) | |
bd414ee6 | 51 | return -EINVAL; |
acc738fe JE |
52 | |
53 | q->master = kmalloc(sizeof(*q->master), GFP_KERNEL); | |
54 | if (q->master == NULL) | |
4a5a5c73 | 55 | return -ENOMEM; |
acc738fe | 56 | |
b0c81aa5 | 57 | spin_lock_init(&q->master->lock); |
6d62182f | 58 | q->master->quota = q->quota; |
bd414ee6 | 59 | return 0; |
62b77434 PM |
60 | } |
61 | ||
acc738fe JE |
62 | static void quota_mt_destroy(const struct xt_mtdtor_param *par) |
63 | { | |
64 | const struct xt_quota_info *q = par->matchinfo; | |
65 | ||
66 | kfree(q->master); | |
67 | } | |
68 | ||
55b69e91 JE |
69 | static struct xt_match quota_mt_reg __read_mostly = { |
70 | .name = "quota", | |
71 | .revision = 0, | |
72 | .family = NFPROTO_UNSPEC, | |
73 | .match = quota_mt, | |
74 | .checkentry = quota_mt_check, | |
acc738fe | 75 | .destroy = quota_mt_destroy, |
55b69e91 | 76 | .matchsize = sizeof(struct xt_quota_info), |
ec231890 | 77 | .usersize = offsetof(struct xt_quota_info, master), |
55b69e91 | 78 | .me = THIS_MODULE, |
62b77434 PM |
79 | }; |
80 | ||
d3c5ee6d | 81 | static int __init quota_mt_init(void) |
62b77434 | 82 | { |
55b69e91 | 83 | return xt_register_match("a_mt_reg); |
62b77434 PM |
84 | } |
85 | ||
d3c5ee6d | 86 | static void __exit quota_mt_exit(void) |
62b77434 | 87 | { |
55b69e91 | 88 | xt_unregister_match("a_mt_reg); |
62b77434 PM |
89 | } |
90 | ||
d3c5ee6d JE |
91 | module_init(quota_mt_init); |
92 | module_exit(quota_mt_exit); |