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5859034d PM |
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> | |
1e90474c | 15 | #include <net/netlink.h> |
5859034d PM |
16 | |
17 | #include <linux/netfilter/x_tables.h> | |
18 | #include <linux/netfilter/xt_RATEEST.h> | |
19 | #include <net/netfilter/xt_rateest.h> | |
20 | ||
21 | static DEFINE_MUTEX(xt_rateest_mutex); | |
22 | ||
23 | #define RATEEST_HSIZE 16 | |
24 | static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly; | |
25 | static unsigned int jhash_rnd __read_mostly; | |
26 | ||
27 | static 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 | ||
33 | static 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 | ||
41 | struct 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 | } | |
59 | EXPORT_SYMBOL_GPL(xt_rateest_lookup); | |
60 | ||
61 | void 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 | } | |
71 | EXPORT_SYMBOL_GPL(xt_rateest_put); | |
72 | ||
73 | static unsigned int | |
7eb35586 | 74 | xt_rateest_tg(struct sk_buff *skb, const struct xt_target_param *par) |
5859034d | 75 | { |
7eb35586 | 76 | const struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
77 | struct gnet_stats_basic *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 | ||
af5d6dc2 | 87 | static bool xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) |
5859034d | 88 | { |
af5d6dc2 | 89 | struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
90 | struct xt_rateest *est; |
91 | struct { | |
1e90474c | 92 | struct nlattr opt; |
5859034d PM |
93 | struct gnet_estimator est; |
94 | } cfg; | |
95 | ||
96 | est = xt_rateest_lookup(info->name); | |
97 | if (est) { | |
98 | /* | |
99 | * If estimator parameters are specified, they must match the | |
100 | * existing estimator. | |
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 | ||
1e90474c PM |
122 | cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); |
123 | cfg.opt.nla_type = TCA_STATS_RATE_EST; | |
5859034d PM |
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 | ||
136 | err2: | |
137 | kfree(est); | |
138 | err1: | |
139 | return false; | |
140 | } | |
141 | ||
a2df1648 | 142 | static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) |
5859034d | 143 | { |
a2df1648 | 144 | struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
145 | |
146 | xt_rateest_put(info->est); | |
147 | } | |
148 | ||
55b69e91 JE |
149 | static 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, | |
5859034d PM |
158 | }; |
159 | ||
160 | static 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)); | |
55b69e91 | 168 | return xt_register_target(&xt_rateest_tg_reg); |
5859034d PM |
169 | } |
170 | ||
171 | static void __exit xt_rateest_tg_fini(void) | |
172 | { | |
55b69e91 | 173 | xt_unregister_target(&xt_rateest_tg_reg); |
5859034d PM |
174 | } |
175 | ||
176 | ||
177 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
178 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 179 | MODULE_DESCRIPTION("Xtables: packet rate estimator"); |
5859034d PM |
180 | MODULE_ALIAS("ipt_RATEEST"); |
181 | MODULE_ALIAS("ip6t_RATEEST"); | |
182 | module_init(xt_rateest_tg_init); | |
183 | module_exit(xt_rateest_tg_fini); |