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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 | |
74 | xt_rateest_tg(struct sk_buff *skb, | |
75 | const struct net_device *in, | |
76 | const struct net_device *out, | |
77 | unsigned int hooknum, | |
78 | const struct xt_target *target, | |
79 | const void *targinfo) | |
80 | { | |
81 | const struct xt_rateest_target_info *info = targinfo; | |
82 | struct gnet_stats_basic *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 | ||
92 | static bool | |
93 | xt_rateest_tg_checkentry(const char *tablename, | |
94 | const void *entry, | |
95 | const struct xt_target *target, | |
96 | void *targinfo, | |
97 | unsigned int hook_mask) | |
98 | { | |
3cf93c96 | 99 | struct xt_rateest_target_info *info = targinfo; |
5859034d PM |
100 | struct xt_rateest *est; |
101 | struct { | |
1e90474c | 102 | struct nlattr opt; |
5859034d PM |
103 | struct gnet_estimator est; |
104 | } cfg; | |
105 | ||
106 | est = xt_rateest_lookup(info->name); | |
107 | if (est) { | |
108 | /* | |
109 | * If estimator parameters are specified, they must match the | |
110 | * existing estimator. | |
111 | */ | |
112 | if ((!info->interval && !info->ewma_log) || | |
113 | (info->interval != est->params.interval || | |
114 | info->ewma_log != est->params.ewma_log)) { | |
115 | xt_rateest_put(est); | |
116 | return false; | |
117 | } | |
118 | info->est = est; | |
119 | return true; | |
120 | } | |
121 | ||
122 | est = kzalloc(sizeof(*est), GFP_KERNEL); | |
123 | if (!est) | |
124 | goto err1; | |
125 | ||
126 | strlcpy(est->name, info->name, sizeof(est->name)); | |
127 | spin_lock_init(&est->lock); | |
128 | est->refcnt = 1; | |
129 | est->params.interval = info->interval; | |
130 | est->params.ewma_log = info->ewma_log; | |
131 | ||
1e90474c PM |
132 | cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); |
133 | cfg.opt.nla_type = TCA_STATS_RATE_EST; | |
5859034d PM |
134 | cfg.est.interval = info->interval; |
135 | cfg.est.ewma_log = info->ewma_log; | |
136 | ||
137 | if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock, | |
138 | &cfg.opt) < 0) | |
139 | goto err2; | |
140 | ||
141 | info->est = est; | |
142 | xt_rateest_hash_insert(est); | |
143 | ||
144 | return true; | |
145 | ||
146 | err2: | |
147 | kfree(est); | |
148 | err1: | |
149 | return false; | |
150 | } | |
151 | ||
152 | static void xt_rateest_tg_destroy(const struct xt_target *target, | |
153 | void *targinfo) | |
154 | { | |
155 | struct xt_rateest_target_info *info = targinfo; | |
156 | ||
157 | xt_rateest_put(info->est); | |
158 | } | |
159 | ||
160 | static struct xt_target xt_rateest_target[] __read_mostly = { | |
161 | { | |
162 | .family = AF_INET, | |
163 | .name = "RATEEST", | |
164 | .target = xt_rateest_tg, | |
165 | .checkentry = xt_rateest_tg_checkentry, | |
166 | .destroy = xt_rateest_tg_destroy, | |
167 | .targetsize = sizeof(struct xt_rateest_target_info), | |
168 | .me = THIS_MODULE, | |
169 | }, | |
170 | { | |
171 | .family = AF_INET6, | |
172 | .name = "RATEEST", | |
173 | .target = xt_rateest_tg, | |
174 | .checkentry = xt_rateest_tg_checkentry, | |
175 | .destroy = xt_rateest_tg_destroy, | |
176 | .targetsize = sizeof(struct xt_rateest_target_info), | |
177 | .me = THIS_MODULE, | |
178 | }, | |
179 | }; | |
180 | ||
181 | static int __init xt_rateest_tg_init(void) | |
182 | { | |
183 | unsigned int i; | |
184 | ||
185 | for (i = 0; i < ARRAY_SIZE(rateest_hash); i++) | |
186 | INIT_HLIST_HEAD(&rateest_hash[i]); | |
187 | ||
188 | get_random_bytes(&jhash_rnd, sizeof(jhash_rnd)); | |
189 | return xt_register_targets(xt_rateest_target, | |
190 | ARRAY_SIZE(xt_rateest_target)); | |
191 | } | |
192 | ||
193 | static void __exit xt_rateest_tg_fini(void) | |
194 | { | |
195 | xt_unregister_targets(xt_rateest_target, ARRAY_SIZE(xt_rateest_target)); | |
196 | } | |
197 | ||
198 | ||
199 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
200 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 201 | MODULE_DESCRIPTION("Xtables: packet rate estimator"); |
5859034d PM |
202 | MODULE_ALIAS("ipt_RATEEST"); |
203 | MODULE_ALIAS("ip6t_RATEEST"); | |
204 | module_init(xt_rateest_tg_init); | |
205 | module_exit(xt_rateest_tg_fini); |