Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
1/*
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>
14#include <linux/slab.h>
15#include <net/gen_stats.h>
16#include <net/netlink.h>
17
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;
27static bool rnd_inited __read_mostly;
28
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;
46 struct hlist_node *n;
47 unsigned int h;
48
49 h = xt_rateest_hash(name);
50 mutex_lock(&xt_rateest_mutex);
51 hlist_for_each_entry(est, n, &rateest_hash[h], list) {
52 if (strcmp(est->name, name) == 0) {
53 est->refcnt++;
54 mutex_unlock(&xt_rateest_mutex);
55 return est;
56 }
57 }
58 mutex_unlock(&xt_rateest_mutex);
59 return NULL;
60}
61EXPORT_SYMBOL_GPL(xt_rateest_lookup);
62
63static void xt_rateest_free_rcu(struct rcu_head *head)
64{
65 kfree(container_of(head, struct xt_rateest, rcu));
66}
67
68void xt_rateest_put(struct xt_rateest *est)
69{
70 mutex_lock(&xt_rateest_mutex);
71 if (--est->refcnt == 0) {
72 hlist_del(&est->list);
73 gen_kill_estimator(&est->bstats, &est->rstats);
74 /*
75 * gen_estimator est_timer() might access est->lock or bstats,
76 * wait a RCU grace period before freeing 'est'
77 */
78 call_rcu(&est->rcu, xt_rateest_free_rcu);
79 }
80 mutex_unlock(&xt_rateest_mutex);
81}
82EXPORT_SYMBOL_GPL(xt_rateest_put);
83
84static unsigned int
85xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
86{
87 const struct xt_rateest_target_info *info = par->targinfo;
88 struct gnet_stats_basic_packed *stats = &info->est->bstats;
89
90 spin_lock_bh(&info->est->lock);
91 stats->bytes += skb->len;
92 stats->packets++;
93 spin_unlock_bh(&info->est->lock);
94
95 return XT_CONTINUE;
96}
97
98static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
99{
100 struct xt_rateest_target_info *info = par->targinfo;
101 struct xt_rateest *est;
102 struct {
103 struct nlattr opt;
104 struct gnet_estimator est;
105 } cfg;
106 int ret;
107
108 if (unlikely(!rnd_inited)) {
109 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
110 rnd_inited = true;
111 }
112
113 est = xt_rateest_lookup(info->name);
114 if (est) {
115 /*
116 * If estimator parameters are specified, they must match the
117 * existing estimator.
118 */
119 if ((!info->interval && !info->ewma_log) ||
120 (info->interval != est->params.interval ||
121 info->ewma_log != est->params.ewma_log)) {
122 xt_rateest_put(est);
123 return -EINVAL;
124 }
125 info->est = est;
126 return 0;
127 }
128
129 ret = -ENOMEM;
130 est = kzalloc(sizeof(*est), GFP_KERNEL);
131 if (!est)
132 goto err1;
133
134 strlcpy(est->name, info->name, sizeof(est->name));
135 spin_lock_init(&est->lock);
136 est->refcnt = 1;
137 est->params.interval = info->interval;
138 est->params.ewma_log = info->ewma_log;
139
140 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
141 cfg.opt.nla_type = TCA_STATS_RATE_EST;
142 cfg.est.interval = info->interval;
143 cfg.est.ewma_log = info->ewma_log;
144
145 ret = gen_new_estimator(&est->bstats, &est->rstats,
146 &est->lock, &cfg.opt);
147 if (ret < 0)
148 goto err2;
149
150 info->est = est;
151 xt_rateest_hash_insert(est);
152 return 0;
153
154err2:
155 kfree(est);
156err1:
157 return ret;
158}
159
160static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
161{
162 struct xt_rateest_target_info *info = par->targinfo;
163
164 xt_rateest_put(info->est);
165}
166
167static struct xt_target xt_rateest_tg_reg __read_mostly = {
168 .name = "RATEEST",
169 .revision = 0,
170 .family = NFPROTO_UNSPEC,
171 .target = xt_rateest_tg,
172 .checkentry = xt_rateest_tg_checkentry,
173 .destroy = xt_rateest_tg_destroy,
174 .targetsize = sizeof(struct xt_rateest_target_info),
175 .me = THIS_MODULE,
176};
177
178static int __init xt_rateest_tg_init(void)
179{
180 unsigned int i;
181
182 for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
183 INIT_HLIST_HEAD(&rateest_hash[i]);
184
185 return xt_register_target(&xt_rateest_tg_reg);
186}
187
188static void __exit xt_rateest_tg_fini(void)
189{
190 xt_unregister_target(&xt_rateest_tg_reg);
191 rcu_barrier(); /* Wait for completion of call_rcu()'s (xt_rateest_free_rcu) */
192}
193
194
195MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
196MODULE_LICENSE("GPL");
197MODULE_DESCRIPTION("Xtables: packet rate estimator");
198MODULE_ALIAS("ipt_RATEEST");
199MODULE_ALIAS("ip6t_RATEEST");
200module_init(xt_rateest_tg_init);
201module_exit(xt_rateest_tg_fini);