1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
static DEFINE_SPINLOCK(limit_lock);
struct nft_limit {
u64 last;
u64 tokens;
u64 tokens_max;
u64 rate;
u64 nsecs;
};
static inline bool nft_limit_eval(struct nft_limit *limit, u64 cost)
{
u64 now, tokens;
s64 delta;
spin_lock_bh(&limit_lock);
now = ktime_get_ns();
tokens = limit->tokens + now - limit->last;
if (tokens > limit->tokens_max)
tokens = limit->tokens_max;
limit->last = now;
delta = tokens - cost;
if (delta >= 0) {
limit->tokens = delta;
spin_unlock_bh(&limit_lock);
return false;
}
limit->tokens = tokens;
spin_unlock_bh(&limit_lock);
return true;
}
static int nft_limit_init(struct nft_limit *limit,
const struct nlattr * const tb[])
{
u64 unit;
if (tb[NFTA_LIMIT_RATE] == NULL ||
tb[NFTA_LIMIT_UNIT] == NULL)
return -EINVAL;
limit->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
limit->nsecs = unit * NSEC_PER_SEC;
if (limit->rate == 0 || limit->nsecs < unit)
return -EOVERFLOW;
limit->tokens = limit->tokens_max = limit->nsecs;
limit->last = ktime_get_ns();
return 0;
}
static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit *limit)
{
u64 secs = div_u64(limit->nsecs, NSEC_PER_SEC);
if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(limit->rate)) ||
nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs)))
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static void nft_limit_pkts_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_limit *priv = nft_expr_priv(expr);
if (nft_limit_eval(priv, div_u64(priv->nsecs, priv->rate)))
regs->verdict.code = NFT_BREAK;
}
static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
[NFTA_LIMIT_RATE] = { .type = NLA_U64 },
[NFTA_LIMIT_UNIT] = { .type = NLA_U64 },
};
static int nft_limit_pkts_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_limit *priv = nft_expr_priv(expr);
return nft_limit_init(priv, tb);
}
static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_limit *priv = nft_expr_priv(expr);
return nft_limit_dump(skb, priv);
}
static struct nft_expr_type nft_limit_type;
static const struct nft_expr_ops nft_limit_pkts_ops = {
.type = &nft_limit_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_limit)),
.eval = nft_limit_pkts_eval,
.init = nft_limit_pkts_init,
.dump = nft_limit_pkts_dump,
};
static struct nft_expr_type nft_limit_type __read_mostly = {
.name = "limit",
.ops = &nft_limit_pkts_ops,
.policy = nft_limit_policy,
.maxattr = NFTA_LIMIT_MAX,
.flags = NFT_EXPR_STATEFUL,
.owner = THIS_MODULE,
};
static int __init nft_limit_module_init(void)
{
return nft_register_expr(&nft_limit_type);
}
static void __exit nft_limit_module_exit(void)
{
nft_unregister_expr(&nft_limit_type);
}
module_init(nft_limit_module_init);
module_exit(nft_limit_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_ALIAS_NFT_EXPR("limit");
|
