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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 unsigned int h;
47
48 h = xt_rateest_hash(name);
49 mutex_lock(&xt_rateest_mutex);
50 hlist_for_each_entry(est, &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
69
70
71
72 kfree_rcu(est, rcu);
73 }
74 mutex_unlock(&xt_rateest_mutex);
75}
76EXPORT_SYMBOL_GPL(xt_rateest_put);
77
78static unsigned int
79xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
80{
81 const struct xt_rateest_target_info *info = par->targinfo;
82 struct gnet_stats_basic_packed *stats = &info->est->bstats;
83
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
92static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
93{
94 struct xt_rateest_target_info *info = par->targinfo;
95 struct xt_rateest *est;
96 struct {
97 struct nlattr opt;
98 struct gnet_estimator est;
99 } cfg;
100 int ret;
101
102 if (unlikely(!rnd_inited)) {
103 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
104 rnd_inited = true;
105 }
106
107 est = xt_rateest_lookup(info->name);
108 if (est) {
109
110
111
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);
117 return -EINVAL;
118 }
119 info->est = est;
120 return 0;
121 }
122
123 ret = -ENOMEM;
124 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
134 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
135 cfg.opt.nla_type = TCA_STATS_RATE_EST;
136 cfg.est.interval = info->interval;
137 cfg.est.ewma_log = info->ewma_log;
138
139 ret = gen_new_estimator(&est->bstats, NULL, &est->rstats,
140 &est->lock, &cfg.opt);
141 if (ret < 0)
142 goto err2;
143
144 info->est = est;
145 xt_rateest_hash_insert(est);
146 return 0;
147
148err2:
149 kfree(est);
150err1:
151 return ret;
152}
153
154static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
155{
156 struct xt_rateest_target_info *info = par->targinfo;
157
158 xt_rateest_put(info->est);
159}
160
161static 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,
170};
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
179 return xt_register_target(&xt_rateest_tg_reg);
180}
181
182static void __exit xt_rateest_tg_fini(void)
183{
184 xt_unregister_target(&xt_rateest_tg_reg);
185}
186
187
188MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
189MODULE_LICENSE("GPL");
190MODULE_DESCRIPTION("Xtables: packet rate estimator");
191MODULE_ALIAS("ipt_RATEEST");
192MODULE_ALIAS("ip6t_RATEEST");
193module_init(xt_rateest_tg_init);
194module_exit(xt_rateest_tg_fini);
195
