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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> | |
15 | ||
16 | #include <linux/netfilter/x_tables.h> | |
17 | #include <linux/netfilter/xt_RATEEST.h> | |
18 | #include <net/netfilter/xt_rateest.h> | |
19 | ||
20 | static DEFINE_MUTEX(xt_rateest_mutex); | |
21 | ||
22 | #define RATEEST_HSIZE 16 | |
23 | static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly; | |
24 | static unsigned int jhash_rnd __read_mostly; | |
25 | ||
26 | static unsigned int xt_rateest_hash(const char *name) | |
27 | { | |
28 | return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) & | |
29 | (RATEEST_HSIZE - 1); | |
30 | } | |
31 | ||
32 | static void xt_rateest_hash_insert(struct xt_rateest *est) | |
33 | { | |
34 | unsigned int h; | |
35 | ||
36 | h = xt_rateest_hash(est->name); | |
37 | hlist_add_head(&est->list, &rateest_hash[h]); | |
38 | } | |
39 | ||
40 | struct xt_rateest *xt_rateest_lookup(const char *name) | |
41 | { | |
42 | struct xt_rateest *est; | |
43 | struct hlist_node *n; | |
44 | unsigned int h; | |
45 | ||
46 | h = xt_rateest_hash(name); | |
47 | mutex_lock(&xt_rateest_mutex); | |
48 | hlist_for_each_entry(est, n, &rateest_hash[h], list) { | |
49 | if (strcmp(est->name, name) == 0) { | |
50 | est->refcnt++; | |
51 | mutex_unlock(&xt_rateest_mutex); | |
52 | return est; | |
53 | } | |
54 | } | |
55 | mutex_unlock(&xt_rateest_mutex); | |
56 | return NULL; | |
57 | } | |
58 | EXPORT_SYMBOL_GPL(xt_rateest_lookup); | |
59 | ||
60 | void xt_rateest_put(struct xt_rateest *est) | |
61 | { | |
62 | mutex_lock(&xt_rateest_mutex); | |
63 | if (--est->refcnt == 0) { | |
64 | hlist_del(&est->list); | |
65 | gen_kill_estimator(&est->bstats, &est->rstats); | |
66 | kfree(est); | |
67 | } | |
68 | mutex_unlock(&xt_rateest_mutex); | |
69 | } | |
70 | EXPORT_SYMBOL_GPL(xt_rateest_put); | |
71 | ||
72 | static unsigned int | |
73 | xt_rateest_tg(struct sk_buff *skb, | |
74 | const struct net_device *in, | |
75 | const struct net_device *out, | |
76 | unsigned int hooknum, | |
77 | const struct xt_target *target, | |
78 | const void *targinfo) | |
79 | { | |
80 | const struct xt_rateest_target_info *info = targinfo; | |
81 | struct gnet_stats_basic *stats = &info->est->bstats; | |
82 | ||
83 | spin_lock_bh(&info->est->lock); | |
84 | stats->bytes += skb->len; | |
85 | stats->packets++; | |
86 | spin_unlock_bh(&info->est->lock); | |
87 | ||
88 | return XT_CONTINUE; | |
89 | } | |
90 | ||
91 | static bool | |
92 | xt_rateest_tg_checkentry(const char *tablename, | |
93 | const void *entry, | |
94 | const struct xt_target *target, | |
95 | void *targinfo, | |
96 | unsigned int hook_mask) | |
97 | { | |
98 | struct xt_rateest_target_info *info = (void *)targinfo; | |
99 | struct xt_rateest *est; | |
100 | struct { | |
101 | struct rtattr opt; | |
102 | struct gnet_estimator est; | |
103 | } cfg; | |
104 | ||
105 | est = xt_rateest_lookup(info->name); | |
106 | if (est) { | |
107 | /* | |
108 | * If estimator parameters are specified, they must match the | |
109 | * existing estimator. | |
110 | */ | |
111 | if ((!info->interval && !info->ewma_log) || | |
112 | (info->interval != est->params.interval || | |
113 | info->ewma_log != est->params.ewma_log)) { | |
114 | xt_rateest_put(est); | |
115 | return false; | |
116 | } | |
117 | info->est = est; | |
118 | return true; | |
119 | } | |
120 | ||
121 | est = kzalloc(sizeof(*est), GFP_KERNEL); | |
122 | if (!est) | |
123 | goto err1; | |
124 | ||
125 | strlcpy(est->name, info->name, sizeof(est->name)); | |
126 | spin_lock_init(&est->lock); | |
127 | est->refcnt = 1; | |
128 | est->params.interval = info->interval; | |
129 | est->params.ewma_log = info->ewma_log; | |
130 | ||
131 | cfg.opt.rta_len = RTA_LENGTH(sizeof(cfg.est)); | |
132 | cfg.opt.rta_type = TCA_STATS_RATE_EST; | |
133 | cfg.est.interval = info->interval; | |
134 | cfg.est.ewma_log = info->ewma_log; | |
135 | ||
136 | if (gen_new_estimator(&est->bstats, &est->rstats, &est->lock, | |
137 | &cfg.opt) < 0) | |
138 | goto err2; | |
139 | ||
140 | info->est = est; | |
141 | xt_rateest_hash_insert(est); | |
142 | ||
143 | return true; | |
144 | ||
145 | err2: | |
146 | kfree(est); | |
147 | err1: | |
148 | return false; | |
149 | } | |
150 | ||
151 | static void xt_rateest_tg_destroy(const struct xt_target *target, | |
152 | void *targinfo) | |
153 | { | |
154 | struct xt_rateest_target_info *info = targinfo; | |
155 | ||
156 | xt_rateest_put(info->est); | |
157 | } | |
158 | ||
159 | static struct xt_target xt_rateest_target[] __read_mostly = { | |
160 | { | |
161 | .family = AF_INET, | |
162 | .name = "RATEEST", | |
163 | .target = xt_rateest_tg, | |
164 | .checkentry = xt_rateest_tg_checkentry, | |
165 | .destroy = xt_rateest_tg_destroy, | |
166 | .targetsize = sizeof(struct xt_rateest_target_info), | |
167 | .me = THIS_MODULE, | |
168 | }, | |
169 | { | |
170 | .family = AF_INET6, | |
171 | .name = "RATEEST", | |
172 | .target = xt_rateest_tg, | |
173 | .checkentry = xt_rateest_tg_checkentry, | |
174 | .destroy = xt_rateest_tg_destroy, | |
175 | .targetsize = sizeof(struct xt_rateest_target_info), | |
176 | .me = THIS_MODULE, | |
177 | }, | |
178 | }; | |
179 | ||
180 | static int __init xt_rateest_tg_init(void) | |
181 | { | |
182 | unsigned int i; | |
183 | ||
184 | for (i = 0; i < ARRAY_SIZE(rateest_hash); i++) | |
185 | INIT_HLIST_HEAD(&rateest_hash[i]); | |
186 | ||
187 | get_random_bytes(&jhash_rnd, sizeof(jhash_rnd)); | |
188 | return xt_register_targets(xt_rateest_target, | |
189 | ARRAY_SIZE(xt_rateest_target)); | |
190 | } | |
191 | ||
192 | static void __exit xt_rateest_tg_fini(void) | |
193 | { | |
194 | xt_unregister_targets(xt_rateest_target, ARRAY_SIZE(xt_rateest_target)); | |
195 | } | |
196 | ||
197 | ||
198 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
199 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 200 | MODULE_DESCRIPTION("Xtables: packet rate estimator"); |
5859034d PM |
201 | MODULE_ALIAS("ipt_RATEEST"); |
202 | MODULE_ALIAS("ip6t_RATEEST"); | |
203 | module_init(xt_rateest_tg_init); | |
204 | module_exit(xt_rateest_tg_fini); |