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96518518 | 1 | /* |
ef1f7df9 | 2 | * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net> |
96518518 PM |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * Development of this code funded by Astaro AG (http://www.astaro.com/) | |
9 | */ | |
10 | ||
11 | #include <linux/kernel.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/spinlock.h> | |
15 | #include <linux/netlink.h> | |
16 | #include <linux/netfilter.h> | |
17 | #include <linux/netfilter/nf_tables.h> | |
18 | #include <net/netfilter/nf_tables.h> | |
19 | ||
20 | static DEFINE_SPINLOCK(limit_lock); | |
21 | ||
22 | struct nft_limit { | |
23 | u64 tokens; | |
24 | u64 rate; | |
25 | u64 unit; | |
26 | unsigned long stamp; | |
27 | }; | |
28 | ||
29 | static void nft_limit_eval(const struct nft_expr *expr, | |
a55e22e9 | 30 | struct nft_regs *regs, |
96518518 PM |
31 | const struct nft_pktinfo *pkt) |
32 | { | |
33 | struct nft_limit *priv = nft_expr_priv(expr); | |
34 | ||
35 | spin_lock_bh(&limit_lock); | |
36 | if (time_after_eq(jiffies, priv->stamp)) { | |
37 | priv->tokens = priv->rate; | |
38 | priv->stamp = jiffies + priv->unit * HZ; | |
39 | } | |
40 | ||
41 | if (priv->tokens >= 1) { | |
42 | priv->tokens--; | |
43 | spin_unlock_bh(&limit_lock); | |
44 | return; | |
45 | } | |
46 | spin_unlock_bh(&limit_lock); | |
47 | ||
a55e22e9 | 48 | regs->verdict.code = NFT_BREAK; |
96518518 PM |
49 | } |
50 | ||
51 | static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = { | |
52 | [NFTA_LIMIT_RATE] = { .type = NLA_U64 }, | |
53 | [NFTA_LIMIT_UNIT] = { .type = NLA_U64 }, | |
54 | }; | |
55 | ||
56 | static int nft_limit_init(const struct nft_ctx *ctx, | |
57 | const struct nft_expr *expr, | |
58 | const struct nlattr * const tb[]) | |
59 | { | |
60 | struct nft_limit *priv = nft_expr_priv(expr); | |
61 | ||
62 | if (tb[NFTA_LIMIT_RATE] == NULL || | |
63 | tb[NFTA_LIMIT_UNIT] == NULL) | |
64 | return -EINVAL; | |
65 | ||
66 | priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE])); | |
67 | priv->unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT])); | |
68 | priv->stamp = jiffies + priv->unit * HZ; | |
69 | priv->tokens = priv->rate; | |
70 | return 0; | |
71 | } | |
72 | ||
73 | static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr) | |
74 | { | |
75 | const struct nft_limit *priv = nft_expr_priv(expr); | |
76 | ||
77 | if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate))) | |
78 | goto nla_put_failure; | |
79 | if (nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(priv->unit))) | |
80 | goto nla_put_failure; | |
81 | return 0; | |
82 | ||
83 | nla_put_failure: | |
84 | return -1; | |
85 | } | |
86 | ||
ef1f7df9 PM |
87 | static struct nft_expr_type nft_limit_type; |
88 | static const struct nft_expr_ops nft_limit_ops = { | |
89 | .type = &nft_limit_type, | |
96518518 | 90 | .size = NFT_EXPR_SIZE(sizeof(struct nft_limit)), |
96518518 PM |
91 | .eval = nft_limit_eval, |
92 | .init = nft_limit_init, | |
93 | .dump = nft_limit_dump, | |
ef1f7df9 PM |
94 | }; |
95 | ||
96 | static struct nft_expr_type nft_limit_type __read_mostly = { | |
97 | .name = "limit", | |
98 | .ops = &nft_limit_ops, | |
96518518 PM |
99 | .policy = nft_limit_policy, |
100 | .maxattr = NFTA_LIMIT_MAX, | |
151d799a | 101 | .flags = NFT_EXPR_STATEFUL, |
ef1f7df9 | 102 | .owner = THIS_MODULE, |
96518518 PM |
103 | }; |
104 | ||
105 | static int __init nft_limit_module_init(void) | |
106 | { | |
ef1f7df9 | 107 | return nft_register_expr(&nft_limit_type); |
96518518 PM |
108 | } |
109 | ||
110 | static void __exit nft_limit_module_exit(void) | |
111 | { | |
ef1f7df9 | 112 | nft_unregister_expr(&nft_limit_type); |
96518518 PM |
113 | } |
114 | ||
115 | module_init(nft_limit_module_init); | |
116 | module_exit(nft_limit_module_exit); | |
117 | ||
118 | MODULE_LICENSE("GPL"); | |
119 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
120 | MODULE_ALIAS_NFT_EXPR("limit"); |