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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 <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;
26
27static unsigned int xt_rateest_hash(const char *name)
28{
29 return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) &
30 (RATEEST_HSIZE - 1);
31}
32
33static void xt_rateest_hash_insert(struct xt_rateest *est)
34{
35 unsigned int h;
36
37 h = xt_rateest_hash(est->name);
38 hlist_add_head(&est->list, &rateest_hash[h]);
39}
40
41struct xt_rateest *xt_rateest_lookup(const char *name)
42{
43 struct xt_rateest *est;
44 struct hlist_node *n;
45 unsigned int h;
46
47 h = xt_rateest_hash(name);
48 mutex_lock(&xt_rateest_mutex);
49 hlist_for_each_entry(est, n, &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->bstats, &est->rstats);
67 kfree(est);
68 }
69 mutex_unlock(&xt_rateest_mutex);
70}
71EXPORT_SYMBOL_GPL(xt_rateest_put);
72
73static unsigned int
74xt_rateest_tg(struct sk_buff *skb, const struct xt_target_param *par)
75{
76 const struct xt_rateest_target_info *info = par->targinfo;
77 struct gnet_stats_basic_packed *stats = &info->est->bstats;
78
79 spin_lock_bh(&info->est->lock);
80 stats->bytes += skb->len;
81 stats->packets++;
82 spin_unlock_bh(&info->est->lock);
83
84 return XT_CONTINUE;
85}
86
87static bool xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
88{
89 struct xt_rateest_target_info *info = par->targinfo;
90 struct xt_rateest *est;
91 struct {
92 struct nlattr opt;
93 struct gnet_estimator est;
94 } cfg;
95
96 est = xt_rateest_lookup(info->name);
97 if (est) {
98
99
100
101
102 if ((!info->interval && !info->ewma_log) ||
103 (info->interval != est->params.interval ||
104 info->ewma_log != est->params.ewma_log)) {
105 xt_rateest_put(est);
106 return false;
107 }
108 info->est = est;
109 return true;
110 }
111
112 est = kzalloc(sizeof(*est), GFP_KERNEL);
113 if (!est)
114 goto err1;
115
116 strlcpy(est->name, info->name, sizeof(est->name));
117 spin_lock_init(&est->lock);
118 est->refcnt = 1;
119 est->params.interval = info->interval;
120 est->params.ewma_log = info->ewma_log;
121
122 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
123 cfg.opt.nla_type = TCA_STATS_RATE_EST;
124 cfg.est.interval = info->interval;
125 cfg.est.ewma_log = info->ewma_log;
126
127 if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock,
128 &cfg.opt) < 0)
129 goto err2;
130
131 info->est = est;
132 xt_rateest_hash_insert(est);
133
134 return true;
135
136err2:
137 kfree(est);
138err1:
139 return false;
140}
141
142static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
143{
144 struct xt_rateest_target_info *info = par->targinfo;
145
146 xt_rateest_put(info->est);
147}
148
149static struct xt_target xt_rateest_tg_reg __read_mostly = {
150 .name = "RATEEST",
151 .revision = 0,
152 .family = NFPROTO_UNSPEC,
153 .target = xt_rateest_tg,
154 .checkentry = xt_rateest_tg_checkentry,
155 .destroy = xt_rateest_tg_destroy,
156 .targetsize = sizeof(struct xt_rateest_target_info),
157 .me = THIS_MODULE,
158};
159
160static int __init xt_rateest_tg_init(void)
161{
162 unsigned int i;
163
164 for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
165 INIT_HLIST_HEAD(&rateest_hash[i]);
166
167 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
168 return xt_register_target(&xt_rateest_tg_reg);
169}
170
171static void __exit xt_rateest_tg_fini(void)
172{
173 xt_unregister_target(&xt_rateest_tg_reg);
174}
175
176
177MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
178MODULE_LICENSE("GPL");
179MODULE_DESCRIPTION("Xtables: packet rate estimator");
180MODULE_ALIAS("ipt_RATEEST");
181MODULE_ALIAS("ip6t_RATEEST");
182module_init(xt_rateest_tg_init);
183module_exit(xt_rateest_tg_fini);
184
