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Patrick McHardy58590342007-12-04 23:40:05 -08001/*
2 * (C) 2007 Patrick McHardy <kaber@trash.net>
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#include <linux/module.h>
9#include <linux/skbuff.h>
10#include <linux/gen_stats.h>
11#include <linux/jhash.h>
12#include <linux/rtnetlink.h>
13#include <linux/random.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090014#include <linux/slab.h>
Patrick McHardy58590342007-12-04 23:40:05 -080015#include <net/gen_stats.h>
Patrick McHardy1e904742008-01-22 22:11:17 -080016#include <net/netlink.h>
Patrick McHardy58590342007-12-04 23:40:05 -080017
18#include <linux/netfilter/x_tables.h>
19#include <linux/netfilter/xt_RATEEST.h>
20#include <net/netfilter/xt_rateest.h>
21
22static DEFINE_MUTEX(xt_rateest_mutex);
23
24#define RATEEST_HSIZE 16
25static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;
26static unsigned int jhash_rnd __read_mostly;
Jan Engelhardt5191d502010-01-04 16:27:25 +010027static bool rnd_inited __read_mostly;
Patrick McHardy58590342007-12-04 23:40:05 -080028
29static unsigned int xt_rateest_hash(const char *name)
30{
31 return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
32 (RATEEST_HSIZE - 1);
33}
34
35static void xt_rateest_hash_insert(struct xt_rateest *est)
36{
37 unsigned int h;
38
39 h = xt_rateest_hash(est->name);
40 hlist_add_head(&est->list, &rateest_hash[h]);
41}
42
43struct xt_rateest *xt_rateest_lookup(const char *name)
44{
45 struct xt_rateest *est;
Patrick McHardy58590342007-12-04 23:40:05 -080046 unsigned int h;
47
48 h = xt_rateest_hash(name);
49 mutex_lock(&xt_rateest_mutex);
Sasha Levinb67bfe02013-02-27 17:06:00 -080050 hlist_for_each_entry(est, &rateest_hash[h], list) {
Patrick McHardy58590342007-12-04 23:40:05 -080051 if (strcmp(est->name, name) == 0) {
52 est->refcnt++;
53 mutex_unlock(&xt_rateest_mutex);
54 return est;
55 }
56 }
57 mutex_unlock(&xt_rateest_mutex);
58 return NULL;
59}
60EXPORT_SYMBOL_GPL(xt_rateest_lookup);
61
62void xt_rateest_put(struct xt_rateest *est)
63{
64 mutex_lock(&xt_rateest_mutex);
65 if (--est->refcnt == 0) {
66 hlist_del(&est->list);
67 gen_kill_estimator(&est->bstats, &est->rstats);
Eric Dumazetc7de2cf2010-06-09 02:09:23 +000068 /*
69 * gen_estimator est_timer() might access est->lock or bstats,
70 * wait a RCU grace period before freeing 'est'
71 */
Paul E. McKenneycefcb602011-05-02 01:00:18 -070072 kfree_rcu(est, rcu);
Patrick McHardy58590342007-12-04 23:40:05 -080073 }
74 mutex_unlock(&xt_rateest_mutex);
75}
76EXPORT_SYMBOL_GPL(xt_rateest_put);
77
78static unsigned int
Jan Engelhardt4b560b42009-07-05 19:43:26 +020079xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
Patrick McHardy58590342007-12-04 23:40:05 -080080{
Jan Engelhardt7eb35582008-10-08 11:35:19 +020081 const struct xt_rateest_target_info *info = par->targinfo;
Eric Dumazetc1a8f1f2009-08-16 09:36:49 +000082 struct gnet_stats_basic_packed *stats = &info->est->bstats;
Patrick McHardy58590342007-12-04 23:40:05 -080083
84 spin_lock_bh(&info->est->lock);
85 stats->bytes += skb->len;
86 stats->packets++;
87 spin_unlock_bh(&info->est->lock);
88
89 return XT_CONTINUE;
90}
91
Jan Engelhardt135367b2010-03-19 17:16:42 +010092static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
Patrick McHardy58590342007-12-04 23:40:05 -080093{
Jan Engelhardtaf5d6dc2008-10-08 11:35:19 +020094 struct xt_rateest_target_info *info = par->targinfo;
Patrick McHardy58590342007-12-04 23:40:05 -080095 struct xt_rateest *est;
96 struct {
Patrick McHardy1e904742008-01-22 22:11:17 -080097 struct nlattr opt;
Patrick McHardy58590342007-12-04 23:40:05 -080098 struct gnet_estimator est;
99 } cfg;
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +0100100 int ret;
Patrick McHardy58590342007-12-04 23:40:05 -0800101
Jan Engelhardt5191d502010-01-04 16:27:25 +0100102 if (unlikely(!rnd_inited)) {
103 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
104 rnd_inited = true;
105 }
106
Patrick McHardy58590342007-12-04 23:40:05 -0800107 est = xt_rateest_lookup(info->name);
108 if (est) {
109 /*
110 * If estimator parameters are specified, they must match the
111 * existing estimator.
112 */
113 if ((!info->interval && !info->ewma_log) ||
114 (info->interval != est->params.interval ||
115 info->ewma_log != est->params.ewma_log)) {
116 xt_rateest_put(est);
Jan Engelhardtd6b00a52010-03-25 16:34:45 +0100117 return -EINVAL;
Patrick McHardy58590342007-12-04 23:40:05 -0800118 }
119 info->est = est;
Jan Engelhardtd6b00a52010-03-25 16:34:45 +0100120 return 0;
Patrick McHardy58590342007-12-04 23:40:05 -0800121 }
122
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +0100123 ret = -ENOMEM;
Patrick McHardy58590342007-12-04 23:40:05 -0800124 est = kzalloc(sizeof(*est), GFP_KERNEL);
125 if (!est)
126 goto err1;
127
128 strlcpy(est->name, info->name, sizeof(est->name));
129 spin_lock_init(&est->lock);
130 est->refcnt = 1;
131 est->params.interval = info->interval;
132 est->params.ewma_log = info->ewma_log;
133
Patrick McHardy1e904742008-01-22 22:11:17 -0800134 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
135 cfg.opt.nla_type = TCA_STATS_RATE_EST;
Patrick McHardy58590342007-12-04 23:40:05 -0800136 cfg.est.interval = info->interval;
137 cfg.est.ewma_log = info->ewma_log;
138
John Fastabend22e0f8b2014-09-28 11:52:56 -0700139 ret = gen_new_estimator(&est->bstats, NULL, &est->rstats,
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +0100140 &est->lock, &cfg.opt);
141 if (ret < 0)
Patrick McHardy58590342007-12-04 23:40:05 -0800142 goto err2;
143
144 info->est = est;
145 xt_rateest_hash_insert(est);
Jan Engelhardtd6b00a52010-03-25 16:34:45 +0100146 return 0;
Patrick McHardy58590342007-12-04 23:40:05 -0800147
148err2:
149 kfree(est);
150err1:
Jan Engelhardt4a5a5c72010-03-19 17:32:59 +0100151 return ret;
Patrick McHardy58590342007-12-04 23:40:05 -0800152}
153
Jan Engelhardta2df1642008-10-08 11:35:19 +0200154static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
Patrick McHardy58590342007-12-04 23:40:05 -0800155{
Jan Engelhardta2df1642008-10-08 11:35:19 +0200156 struct xt_rateest_target_info *info = par->targinfo;
Patrick McHardy58590342007-12-04 23:40:05 -0800157
158 xt_rateest_put(info->est);
159}
160
Jan Engelhardt55b69e92008-10-08 11:35:01 +0200161static struct xt_target xt_rateest_tg_reg __read_mostly = {
162 .name = "RATEEST",
163 .revision = 0,
164 .family = NFPROTO_UNSPEC,
165 .target = xt_rateest_tg,
166 .checkentry = xt_rateest_tg_checkentry,
167 .destroy = xt_rateest_tg_destroy,
168 .targetsize = sizeof(struct xt_rateest_target_info),
169 .me = THIS_MODULE,
Patrick McHardy58590342007-12-04 23:40:05 -0800170};
171
172static int __init xt_rateest_tg_init(void)
173{
174 unsigned int i;
175
176 for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
177 INIT_HLIST_HEAD(&rateest_hash[i]);
178
Jan Engelhardt55b69e92008-10-08 11:35:01 +0200179 return xt_register_target(&xt_rateest_tg_reg);
Patrick McHardy58590342007-12-04 23:40:05 -0800180}
181
182static void __exit xt_rateest_tg_fini(void)
183{
Jan Engelhardt55b69e92008-10-08 11:35:01 +0200184 xt_unregister_target(&xt_rateest_tg_reg);
Patrick McHardy58590342007-12-04 23:40:05 -0800185}
186
187
188MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
189MODULE_LICENSE("GPL");
Jan Engelhardt2ae15b62008-01-14 23:42:28 -0800190MODULE_DESCRIPTION("Xtables: packet rate estimator");
Patrick McHardy58590342007-12-04 23:40:05 -0800191MODULE_ALIAS("ipt_RATEEST");
192MODULE_ALIAS("ip6t_RATEEST");
193module_init(xt_rateest_tg_init);
194module_exit(xt_rateest_tg_fini);