aboutsummaryrefslogtreecommitdiff
path: root/net/netfilter/xt_RATEEST.c
blob: de079abd5bc873ae270abdfaa8d9c28af7df11ba (plain)
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
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * (C) 2007 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.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/gen_stats.h>
#include <linux/jhash.h>
#include <linux/rtnetlink.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <net/gen_stats.h>
#include <net/netlink.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_RATEEST.h>
#include <net/netfilter/xt_rateest.h>

static DEFINE_MUTEX(xt_rateest_mutex);

#define RATEEST_HSIZE	16
static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;
static unsigned int jhash_rnd __read_mostly;
static bool rnd_inited __read_mostly;

static unsigned int xt_rateest_hash(const char *name)
{
	return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
	       (RATEEST_HSIZE - 1);
}

static void xt_rateest_hash_insert(struct xt_rateest *est)
{
	unsigned int h;

	h = xt_rateest_hash(est->name);
	hlist_add_head(&est->list, &rateest_hash[h]);
}

struct xt_rateest *xt_rateest_lookup(const char *name)
{
	struct xt_rateest *est;
	struct hlist_node *n;
	unsigned int h;

	h = xt_rateest_hash(name);
	mutex_lock(&xt_rateest_mutex);
	hlist_for_each_entry(est, n, &rateest_hash[h], list) {
		if (strcmp(est->name, name) == 0) {
			est->refcnt++;
			mutex_unlock(&xt_rateest_mutex);
			return est;
		}
	}
	mutex_unlock(&xt_rateest_mutex);
	return NULL;
}
EXPORT_SYMBOL_GPL(xt_rateest_lookup);

static void xt_rateest_free_rcu(struct rcu_head *head)
{
	kfree(container_of(head, struct xt_rateest, rcu));
}

void xt_rateest_put(struct xt_rateest *est)
{
	mutex_lock(&xt_rateest_mutex);
	if (--est->refcnt == 0) {
		hlist_del(&est->list);
		gen_kill_estimator(&est->bstats, &est->rstats);
		/*
		 * gen_estimator est_timer() might access est->lock or bstats,
		 * wait a RCU grace period before freeing 'est'
		 */
		call_rcu(&est->rcu, xt_rateest_free_rcu);
	}
	mutex_unlock(&xt_rateest_mutex);
}
EXPORT_SYMBOL_GPL(xt_rateest_put);

static unsigned int
xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct xt_rateest_target_info *info = par->targinfo;
	struct gnet_stats_basic_packed *stats = &info->est->bstats;

	spin_lock_bh(&info->est->lock);
	stats->bytes += skb->len;
	stats->packets++;
	spin_unlock_bh(&info->est->lock);

	return XT_CONTINUE;
}

static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
{
	struct xt_rateest_target_info *info = par->targinfo;
	struct xt_rateest *est;
	struct {
		struct nlattr		opt;
		struct gnet_estimator	est;
	} cfg;
	int ret;

	if (unlikely(!rnd_inited)) {
		get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
		rnd_inited = true;
	}

	est = xt_rateest_lookup(info->name);
	if (est) {
		/*
		 * If estimator parameters are specified, they must match the
		 * existing estimator.
		 */
		if ((!info->interval && !info->ewma_log) ||
		    (info->interval != est->params.interval ||
		     info->ewma_log != est->params.ewma_log)) {
			xt_rateest_put(est);
			return -EINVAL;
		}
		info->est = est;
		return 0;
	}

	ret = -ENOMEM;
	est = kzalloc(sizeof(*est), GFP_KERNEL);
	if (!est)
		goto err1;

	strlcpy(est->name, info->name, sizeof(est->name));
	spin_lock_init(&est->lock);
	est->refcnt		= 1;
	est->params.interval	= info->interval;
	est->params.ewma_log	= info->ewma_log;

	cfg.opt.nla_len		= nla_attr_size(sizeof(cfg.est));
	cfg.opt.nla_type	= TCA_STATS_RATE_EST;
	cfg.est.interval	= info->interval;
	cfg.est.ewma_log	= info->ewma_log;

	ret = gen_new_estimator(&est->bstats, &est->rstats,
				&est->lock, &cfg.opt);
	if (ret < 0)
		goto err2;

	info->est = est;
	xt_rateest_hash_insert(est);
	return 0;

err2:
	kfree(est);
err1:
	return ret;
}

static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
{
	struct xt_rateest_target_info *info = par->targinfo;

	xt_rateest_put(info->est);
}

static struct xt_target xt_rateest_tg_reg __read_mostly = {
	.name       = "RATEEST",
	.revision   = 0,
	.family     = NFPROTO_UNSPEC,
	.target     = xt_rateest_tg,
	.checkentry = xt_rateest_tg_checkentry,
	.destroy    = xt_rateest_tg_destroy,
	.targetsize = sizeof(struct xt_rateest_target_info),
	.me         = THIS_MODULE,
};

static int __init xt_rateest_tg_init(void)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
		INIT_HLIST_HEAD(&rateest_hash[i]);

	return xt_register_target(&xt_rateest_tg_reg);
}

static void __exit xt_rateest_tg_fini(void)
{
	xt_unregister_target(&xt_rateest_tg_reg);
	rcu_barrier(); /* Wait for completion of call_rcu()'s (xt_rateest_free_rcu) */
}


MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Xtables: packet rate estimator");
MODULE_ALIAS("ipt_RATEEST");
MODULE_ALIAS("ip6t_RATEEST");
module_init(xt_rateest_tg_init);
module_exit(xt_rateest_tg_fini);