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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; | |
46 | struct hlist_node *n; | |
47 | unsigned int h; | |
48 | ||
49 | h = xt_rateest_hash(name); | |
50 | mutex_lock(&xt_rateest_mutex); | |
51 | hlist_for_each_entry(est, n, &rateest_hash[h], list) { | |
52 | if (strcmp(est->name, name) == 0) { | |
53 | est->refcnt++; | |
54 | mutex_unlock(&xt_rateest_mutex); | |
55 | return est; | |
56 | } | |
57 | } | |
58 | mutex_unlock(&xt_rateest_mutex); | |
59 | return NULL; | |
60 | } | |
61 | EXPORT_SYMBOL_GPL(xt_rateest_lookup); | |
62 | ||
c7de2cf0 ED |
63 | static void xt_rateest_free_rcu(struct rcu_head *head) |
64 | { | |
65 | kfree(container_of(head, struct xt_rateest, rcu)); | |
66 | } | |
67 | ||
5859034d PM |
68 | void xt_rateest_put(struct xt_rateest *est) |
69 | { | |
70 | mutex_lock(&xt_rateest_mutex); | |
71 | if (--est->refcnt == 0) { | |
72 | hlist_del(&est->list); | |
73 | gen_kill_estimator(&est->bstats, &est->rstats); | |
c7de2cf0 ED |
74 | /* |
75 | * gen_estimator est_timer() might access est->lock or bstats, | |
76 | * wait a RCU grace period before freeing 'est' | |
77 | */ | |
78 | call_rcu(&est->rcu, xt_rateest_free_rcu); | |
5859034d PM |
79 | } |
80 | mutex_unlock(&xt_rateest_mutex); | |
81 | } | |
82 | EXPORT_SYMBOL_GPL(xt_rateest_put); | |
83 | ||
84 | static unsigned int | |
4b560b44 | 85 | xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) |
5859034d | 86 | { |
7eb35586 | 87 | const struct xt_rateest_target_info *info = par->targinfo; |
c1a8f1f1 | 88 | struct gnet_stats_basic_packed *stats = &info->est->bstats; |
5859034d PM |
89 | |
90 | spin_lock_bh(&info->est->lock); | |
91 | stats->bytes += skb->len; | |
92 | stats->packets++; | |
93 | spin_unlock_bh(&info->est->lock); | |
94 | ||
95 | return XT_CONTINUE; | |
96 | } | |
97 | ||
135367b8 | 98 | static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) |
5859034d | 99 | { |
af5d6dc2 | 100 | struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
101 | struct xt_rateest *est; |
102 | struct { | |
1e90474c | 103 | struct nlattr opt; |
5859034d PM |
104 | struct gnet_estimator est; |
105 | } cfg; | |
4a5a5c73 | 106 | int ret; |
5859034d | 107 | |
5191d501 JE |
108 | if (unlikely(!rnd_inited)) { |
109 | get_random_bytes(&jhash_rnd, sizeof(jhash_rnd)); | |
110 | rnd_inited = true; | |
111 | } | |
112 | ||
5859034d PM |
113 | est = xt_rateest_lookup(info->name); |
114 | if (est) { | |
115 | /* | |
116 | * If estimator parameters are specified, they must match the | |
117 | * existing estimator. | |
118 | */ | |
119 | if ((!info->interval && !info->ewma_log) || | |
120 | (info->interval != est->params.interval || | |
121 | info->ewma_log != est->params.ewma_log)) { | |
122 | xt_rateest_put(est); | |
d6b00a53 | 123 | return -EINVAL; |
5859034d PM |
124 | } |
125 | info->est = est; | |
d6b00a53 | 126 | return 0; |
5859034d PM |
127 | } |
128 | ||
4a5a5c73 | 129 | ret = -ENOMEM; |
5859034d PM |
130 | est = kzalloc(sizeof(*est), GFP_KERNEL); |
131 | if (!est) | |
132 | goto err1; | |
133 | ||
134 | strlcpy(est->name, info->name, sizeof(est->name)); | |
135 | spin_lock_init(&est->lock); | |
136 | est->refcnt = 1; | |
137 | est->params.interval = info->interval; | |
138 | est->params.ewma_log = info->ewma_log; | |
139 | ||
1e90474c PM |
140 | cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); |
141 | cfg.opt.nla_type = TCA_STATS_RATE_EST; | |
5859034d PM |
142 | cfg.est.interval = info->interval; |
143 | cfg.est.ewma_log = info->ewma_log; | |
144 | ||
4a5a5c73 JE |
145 | ret = gen_new_estimator(&est->bstats, &est->rstats, |
146 | &est->lock, &cfg.opt); | |
147 | if (ret < 0) | |
5859034d PM |
148 | goto err2; |
149 | ||
150 | info->est = est; | |
151 | xt_rateest_hash_insert(est); | |
d6b00a53 | 152 | return 0; |
5859034d PM |
153 | |
154 | err2: | |
155 | kfree(est); | |
156 | err1: | |
4a5a5c73 | 157 | return ret; |
5859034d PM |
158 | } |
159 | ||
a2df1648 | 160 | static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) |
5859034d | 161 | { |
a2df1648 | 162 | struct xt_rateest_target_info *info = par->targinfo; |
5859034d PM |
163 | |
164 | xt_rateest_put(info->est); | |
165 | } | |
166 | ||
55b69e91 JE |
167 | static struct xt_target xt_rateest_tg_reg __read_mostly = { |
168 | .name = "RATEEST", | |
169 | .revision = 0, | |
170 | .family = NFPROTO_UNSPEC, | |
171 | .target = xt_rateest_tg, | |
172 | .checkentry = xt_rateest_tg_checkentry, | |
173 | .destroy = xt_rateest_tg_destroy, | |
174 | .targetsize = sizeof(struct xt_rateest_target_info), | |
175 | .me = THIS_MODULE, | |
5859034d PM |
176 | }; |
177 | ||
178 | static int __init xt_rateest_tg_init(void) | |
179 | { | |
180 | unsigned int i; | |
181 | ||
182 | for (i = 0; i < ARRAY_SIZE(rateest_hash); i++) | |
183 | INIT_HLIST_HEAD(&rateest_hash[i]); | |
184 | ||
55b69e91 | 185 | return xt_register_target(&xt_rateest_tg_reg); |
5859034d PM |
186 | } |
187 | ||
188 | static void __exit xt_rateest_tg_fini(void) | |
189 | { | |
55b69e91 | 190 | xt_unregister_target(&xt_rateest_tg_reg); |
c7de2cf0 | 191 | rcu_barrier(); /* Wait for completion of call_rcu()'s (xt_rateest_free_rcu) */ |
5859034d PM |
192 | } |
193 | ||
194 | ||
195 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); | |
196 | MODULE_LICENSE("GPL"); | |
2ae15b64 | 197 | MODULE_DESCRIPTION("Xtables: packet rate estimator"); |
5859034d PM |
198 | MODULE_ALIAS("ipt_RATEEST"); |
199 | MODULE_ALIAS("ip6t_RATEEST"); | |
200 | module_init(xt_rateest_tg_init); | |
201 | module_exit(xt_rateest_tg_fini); |