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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> | |
5a0e3ad6 | 14 | #include <linux/slab.h> |
5859034d | 15 | #include <net/gen_stats.h> |
1e90474c | 16 | #include <net/netlink.h> |
5859034d PM |
17 | |
18 | #include <linux/netfilter/x_tables.h> | |
19 | #include <linux/netfilter/xt_RATEEST.h> | |
20 | #include <net/netfilter/xt_rateest.h> | |
21 | ||
22 | static DEFINE_MUTEX(xt_rateest_mutex); | |
23 | ||
24 | #define RATEEST_HSIZE 16 | |
25 | static struct hlist_head rateest_hash[RATEEST_HSIZE] __read_mostly; | |
26 | static unsigned int jhash_rnd __read_mostly; | |
5191d501 | 27 | static bool rnd_inited __read_mostly; |
5859034d PM |
28 | |
29 | static 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 | ||
35 | static 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 | ||
43 | struct xt_rateest *xt_rateest_lookup(const char *name) | |
44 | { | |
45 | struct xt_rateest *est; | |
5859034d PM |
46 | unsigned int h; |
47 | ||
48 | h = xt_rateest_hash(name); | |
49 | mutex_lock(&xt_rateest_mutex); | |
b67bfe0d | 50 | hlist_for_each_entry(est, &rateest_hash[h], list) { |
5859034d PM |
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 | } | |
60 | EXPORT_SYMBOL_GPL(xt_rateest_lookup); | |
61 | ||
62 | void 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); | |
c7de2cf0 ED |
68 | /* |
69 | * gen_estimator est_timer() might access est->lock or bstats, | |
70 | * wait a RCU grace period before freeing 'est' | |
71 | */ | |
cefcb602 | 72 | kfree_rcu(est, rcu); |
5859034d PM |
73 | } |
74 | mutex_unlock(&xt_rateest_mutex); | |
75 | } | |
76 | EXPORT_SYMBOL_GPL(xt_rateest_put); | |
77 | ||
78 | static unsigned int | |
4b560b44 | 79 | xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) |
5859034d | 80 | { |
7eb35586 | 81 | const struct xt_rateest_target_info *info = par->targinfo; |
c1a8f1f1 | 82 | struct gnet_stats_basic_packed *stats = &info->est->bstats; |
5859034d PM |
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 | ||
135367b8 | 92 | static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) |
5859034d | 93 | { |
af5d6dc2 | 94 | struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
95 | struct xt_rateest *est; |
96 | struct { | |
1e90474c | 97 | struct nlattr opt; |
5859034d PM |
98 | struct gnet_estimator est; |
99 | } cfg; | |
4a5a5c73 | 100 | int ret; |
5859034d | 101 | |
5191d501 JE |
102 | if (unlikely(!rnd_inited)) { |
103 | get_random_bytes(&jhash_rnd, sizeof(jhash_rnd)); | |
104 | rnd_inited = true; | |
105 | } | |
106 | ||
5859034d PM |
107 | est = xt_rateest_lookup(info->name); |
108 | if (est) { | |
109 | /* | |
110 | * If estimator parameters are specified, they must match the | |
111 | * existing estimator. | |
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); | |
d6b00a53 | 117 | return -EINVAL; |
5859034d PM |
118 | } |
119 | info->est = est; | |
d6b00a53 | 120 | return 0; |
5859034d PM |
121 | } |
122 | ||
4a5a5c73 | 123 | ret = -ENOMEM; |
5859034d PM |
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 | ||
1e90474c PM |
134 | cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); |
135 | cfg.opt.nla_type = TCA_STATS_RATE_EST; | |
5859034d PM |
136 | cfg.est.interval = info->interval; |
137 | cfg.est.ewma_log = info->ewma_log; | |
138 | ||
22e0f8b9 | 139 | ret = gen_new_estimator(&est->bstats, NULL, &est->rstats, |
4a5a5c73 JE |
140 | &est->lock, &cfg.opt); |
141 | if (ret < 0) | |
5859034d PM |
142 | goto err2; |
143 | ||
144 | info->est = est; | |
145 | xt_rateest_hash_insert(est); | |
d6b00a53 | 146 | return 0; |
5859034d PM |
147 | |
148 | err2: | |
149 | kfree(est); | |
150 | err1: | |
4a5a5c73 | 151 | return ret; |
5859034d PM |
152 | } |
153 | ||
a2df1648 | 154 | static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) |
5859034d | 155 | { |
a2df1648 | 156 | struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
157 | |
158 | xt_rateest_put(info->est); | |
159 | } | |
160 | ||
55b69e91 JE |
161 | static 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, | |
5859034d PM |
170 | }; |
171 | ||
172 | static 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 | ||
55b69e91 | 179 | return xt_register_target(&xt_rateest_tg_reg); |
5859034d PM |
180 | } |
181 | ||
182 | static void __exit xt_rateest_tg_fini(void) | |
183 | { | |
55b69e91 | 184 | xt_unregister_target(&xt_rateest_tg_reg); |
5859034d PM |
185 | } |
186 | ||
187 | ||
188 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
189 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 190 | MODULE_DESCRIPTION("Xtables: packet rate estimator"); |
5859034d PM |
191 | MODULE_ALIAS("ipt_RATEEST"); |
192 | MODULE_ALIAS("ip6t_RATEEST"); | |
193 | module_init(xt_rateest_tg_init); | |
194 | module_exit(xt_rateest_tg_fini); |