tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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 <net/gen_stats.h>
15#include <net/netlink.h>
16
17#include <linux/netfilter/x_tables.h>
18#include <linux/netfilter/xt_RATEEST.h>
19#include <net/netfilter/xt_rateest.h>
20
21static DEFINE_MUTEX(xt_rateest_mutex);
22
23#define RATEEST_HSIZE 16
24static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly;
25static unsigned int jhash_rnd __read_mostly;
26static bool rnd_inited __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 struct hlist_node *n;
46 unsigned int h;
47
48 h = xt_rateest_hash(name);
49 mutex_lock(&xt_rateest_mutex);
50 hlist_for_each_entry(est, n, &rateest_hash[h], list) {
51 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);
68 kfree(est);
69 }
70 mutex_unlock(&xt_rateest_mutex);
71}
72EXPORT_SYMBOL_GPL(xt_rateest_put);
73
74static unsigned int
75xt_rateest_tg(struct sk_buff *skb, const struct xt_target_param *par)
76{
77 const struct xt_rateest_target_info *info = par->targinfo;
78 struct gnet_stats_basic_packed *stats = &info->est->bstats;
79
80 spin_lock_bh(&info->est->lock);
81 stats->bytes += skb->len;
82 stats->packets++;
83 spin_unlock_bh(&info->est->lock);
84
85 return XT_CONTINUE;
86}
87
88static bool xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
89{
90 struct xt_rateest_target_info *info = par->targinfo;
91 struct xt_rateest *est;
92 struct {
93 struct nlattr opt;
94 struct gnet_estimator est;
95 } cfg;
96
97 if (unlikely(!rnd_inited)) {
98 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
99 rnd_inited = true;
100 }
101
102 est = xt_rateest_lookup(info->name);
103 if (est) {
104 /*
105 * If estimator parameters are specified, they must match the
106 * existing estimator.
107 */
108 if ((!info->interval && !info->ewma_log) ||
109 (info->interval != est->params.interval ||
110 info->ewma_log != est->params.ewma_log)) {
111 xt_rateest_put(est);
112 return false;
113 }
114 info->est = est;
115 return true;
116 }
117
118 est = kzalloc(sizeof(*est), GFP_KERNEL);
119 if (!est)
120 goto err1;
121
122 strlcpy(est->name, info->name, sizeof(est->name));
123 spin_lock_init(&est->lock);
124 est->refcnt = 1;
125 est->params.interval = info->interval;
126 est->params.ewma_log = info->ewma_log;
127
128 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
129 cfg.opt.nla_type = TCA_STATS_RATE_EST;
130 cfg.est.interval = info->interval;
131 cfg.est.ewma_log = info->ewma_log;
132
133 if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock,
134 &cfg.opt) < 0)
135 goto err2;
136
137 info->est = est;
138 xt_rateest_hash_insert(est);
139
140 return true;
141
142err2:
143 kfree(est);
144err1:
145 return false;
146}
147
148static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
149{
150 struct xt_rateest_target_info *info = par->targinfo;
151
152 xt_rateest_put(info->est);
153}
154
155static struct xt_target xt_rateest_tg_reg __read_mostly = {
156 .name = "RATEEST",
157 .revision = 0,
158 .family = NFPROTO_UNSPEC,
159 .target = xt_rateest_tg,
160 .checkentry = xt_rateest_tg_checkentry,
161 .destroy = xt_rateest_tg_destroy,
162 .targetsize = sizeof(struct xt_rateest_target_info),
163 .me = THIS_MODULE,
164};
165
166static int __init xt_rateest_tg_init(void)
167{
168 unsigned int i;
169
170 for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
171 INIT_HLIST_HEAD(&rateest_hash[i]);
172
173 return xt_register_target(&xt_rateest_tg_reg);
174}
175
176static void __exit xt_rateest_tg_fini(void)
177{
178 xt_unregister_target(&xt_rateest_tg_reg);
179}
180
181
182MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
183MODULE_LICENSE("GPL");
184MODULE_DESCRIPTION("Xtables: packet rate estimator");
185MODULE_ALIAS("ipt_RATEEST");
186MODULE_ALIAS("ip6t_RATEEST");
187module_init(xt_rateest_tg_init);
188module_exit(xt_rateest_tg_fini);