Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
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;
27
28static unsigned int xt_rateest_hash(const char *name)
29{
30 return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
31 (RATEEST_HSIZE - 1);
32}
33
34static void xt_rateest_hash_insert(struct xt_rateest *est)
35{
36 unsigned int h;
37
38 h = xt_rateest_hash(est->name);
39 hlist_add_head(&est->list, &rateest_hash[h]);
40}
41
42struct xt_rateest *xt_rateest_lookup(const char *name)
43{
44 struct xt_rateest *est;
45 unsigned int h;
46
47 h = xt_rateest_hash(name);
48 mutex_lock(&xt_rateest_mutex);
49 hlist_for_each_entry(est, &rateest_hash[h], list) {
50 if (strcmp(est->name, name) == 0) {
51 est->refcnt++;
52 mutex_unlock(&xt_rateest_mutex);
53 return est;
54 }
55 }
56 mutex_unlock(&xt_rateest_mutex);
57 return NULL;
58}
59EXPORT_SYMBOL_GPL(xt_rateest_lookup);
60
61void xt_rateest_put(struct xt_rateest *est)
62{
63 mutex_lock(&xt_rateest_mutex);
64 if (--est->refcnt == 0) {
65 hlist_del(&est->list);
66 gen_kill_estimator(&est->rate_est);
67 /*
68 * gen_estimator est_timer() might access est->lock or bstats,
69 * wait a RCU grace period before freeing 'est'
70 */
71 kfree_rcu(est, rcu);
72 }
73 mutex_unlock(&xt_rateest_mutex);
74}
75EXPORT_SYMBOL_GPL(xt_rateest_put);
76
77static unsigned int
78xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
79{
80 const struct xt_rateest_target_info *info = par->targinfo;
81 struct gnet_stats_basic_packed *stats = &info->est->bstats;
82
83 spin_lock_bh(&info->est->lock);
84 stats->bytes += skb->len;
85 stats->packets++;
86 spin_unlock_bh(&info->est->lock);
87
88 return XT_CONTINUE;
89}
90
91static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
92{
93 struct xt_rateest_target_info *info = par->targinfo;
94 struct xt_rateest *est;
95 struct {
96 struct nlattr opt;
97 struct gnet_estimator est;
98 } cfg;
99 int ret;
100
101 net_get_random_once(&jhash_rnd, sizeof(jhash_rnd));
102
103 est = xt_rateest_lookup(info->name);
104 if (est) {
105 /*
106 * If estimator parameters are specified, they must match the
107 * existing estimator.
108 */
109 if ((!info->interval && !info->ewma_log) ||
110 (info->interval != est->params.interval ||
111 info->ewma_log != est->params.ewma_log)) {
112 xt_rateest_put(est);
113 return -EINVAL;
114 }
115 info->est = est;
116 return 0;
117 }
118
119 ret = -ENOMEM;
120 est = kzalloc(sizeof(*est), GFP_KERNEL);
121 if (!est)
122 goto err1;
123
124 strlcpy(est->name, info->name, sizeof(est->name));
125 spin_lock_init(&est->lock);
126 est->refcnt = 1;
127 est->params.interval = info->interval;
128 est->params.ewma_log = info->ewma_log;
129
130 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
131 cfg.opt.nla_type = TCA_STATS_RATE_EST;
132 cfg.est.interval = info->interval;
133 cfg.est.ewma_log = info->ewma_log;
134
135 ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est,
136 &est->lock, NULL, &cfg.opt);
137 if (ret < 0)
138 goto err2;
139
140 info->est = est;
141 xt_rateest_hash_insert(est);
142 return 0;
143
144err2:
145 kfree(est);
146err1:
147 return ret;
148}
149
150static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
151{
152 struct xt_rateest_target_info *info = par->targinfo;
153
154 xt_rateest_put(info->est);
155}
156
157static struct xt_target xt_rateest_tg_reg __read_mostly = {
158 .name = "RATEEST",
159 .revision = 0,
160 .family = NFPROTO_UNSPEC,
161 .target = xt_rateest_tg,
162 .checkentry = xt_rateest_tg_checkentry,
163 .destroy = xt_rateest_tg_destroy,
164 .targetsize = sizeof(struct xt_rateest_target_info),
165 .usersize = offsetof(struct xt_rateest_target_info, est),
166 .me = THIS_MODULE,
167};
168
169static int __init xt_rateest_tg_init(void)
170{
171 unsigned int i;
172
173 for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
174 INIT_HLIST_HEAD(&rateest_hash[i]);
175
176 return xt_register_target(&xt_rateest_tg_reg);
177}
178
179static void __exit xt_rateest_tg_fini(void)
180{
181 xt_unregister_target(&xt_rateest_tg_reg);
182}
183
184
185MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
186MODULE_LICENSE("GPL");
187MODULE_DESCRIPTION("Xtables: packet rate estimator");
188MODULE_ALIAS("ipt_RATEEST");
189MODULE_ALIAS("ip6t_RATEEST");
190module_init(xt_rateest_tg_init);
191module_exit(xt_rateest_tg_fini);