mqprio: Avoid panic if no options are provided
[linux-2.6.git] / net / netfilter / xt_RATEEST.c
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 <linux/slab.h>
15 #include <net/gen_stats.h>
16 #include <net/netlink.h>
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;
27 static bool rnd_inited __read_mostly;
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
63 void xt_rateest_put(struct xt_rateest *est)
64 {
65         mutex_lock(&xt_rateest_mutex);
66         if (--est->refcnt == 0) {
67                 hlist_del(&est->list);
68                 gen_kill_estimator(&est->bstats, &est->rstats);
69                 /*
70                  * gen_estimator est_timer() might access est->lock or bstats,
71                  * wait a RCU grace period before freeing 'est'
72                  */
73                 kfree_rcu(est, rcu);
74         }
75         mutex_unlock(&xt_rateest_mutex);
76 }
77 EXPORT_SYMBOL_GPL(xt_rateest_put);
78
79 static unsigned int
80 xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par)
81 {
82         const struct xt_rateest_target_info *info = par->targinfo;
83         struct gnet_stats_basic_packed *stats = &info->est->bstats;
84
85         spin_lock_bh(&info->est->lock);
86         stats->bytes += skb->len;
87         stats->packets++;
88         spin_unlock_bh(&info->est->lock);
89
90         return XT_CONTINUE;
91 }
92
93 static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par)
94 {
95         struct xt_rateest_target_info *info = par->targinfo;
96         struct xt_rateest *est;
97         struct {
98                 struct nlattr           opt;
99                 struct gnet_estimator   est;
100         } cfg;
101         int ret;
102
103         if (unlikely(!rnd_inited)) {
104                 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd));
105                 rnd_inited = true;
106         }
107
108         est = xt_rateest_lookup(info->name);
109         if (est) {
110                 /*
111                  * If estimator parameters are specified, they must match the
112                  * existing estimator.
113                  */
114                 if ((!info->interval && !info->ewma_log) ||
115                     (info->interval != est->params.interval ||
116                      info->ewma_log != est->params.ewma_log)) {
117                         xt_rateest_put(est);
118                         return -EINVAL;
119                 }
120                 info->est = est;
121                 return 0;
122         }
123
124         ret = -ENOMEM;
125         est = kzalloc(sizeof(*est), GFP_KERNEL);
126         if (!est)
127                 goto err1;
128
129         strlcpy(est->name, info->name, sizeof(est->name));
130         spin_lock_init(&est->lock);
131         est->refcnt             = 1;
132         est->params.interval    = info->interval;
133         est->params.ewma_log    = info->ewma_log;
134
135         cfg.opt.nla_len         = nla_attr_size(sizeof(cfg.est));
136         cfg.opt.nla_type        = TCA_STATS_RATE_EST;
137         cfg.est.interval        = info->interval;
138         cfg.est.ewma_log        = info->ewma_log;
139
140         ret = gen_new_estimator(&est->bstats, &est->rstats,
141                                 &est->lock, &cfg.opt);
142         if (ret < 0)
143                 goto err2;
144
145         info->est = est;
146         xt_rateest_hash_insert(est);
147         return 0;
148
149 err2:
150         kfree(est);
151 err1:
152         return ret;
153 }
154
155 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
156 {
157         struct xt_rateest_target_info *info = par->targinfo;
158
159         xt_rateest_put(info->est);
160 }
161
162 static struct xt_target xt_rateest_tg_reg __read_mostly = {
163         .name       = "RATEEST",
164         .revision   = 0,
165         .family     = NFPROTO_UNSPEC,
166         .target     = xt_rateest_tg,
167         .checkentry = xt_rateest_tg_checkentry,
168         .destroy    = xt_rateest_tg_destroy,
169         .targetsize = sizeof(struct xt_rateest_target_info),
170         .me         = THIS_MODULE,
171 };
172
173 static int __init xt_rateest_tg_init(void)
174 {
175         unsigned int i;
176
177         for (i = 0; i < ARRAY_SIZE(rateest_hash); i++)
178                 INIT_HLIST_HEAD(&rateest_hash[i]);
179
180         return xt_register_target(&xt_rateest_tg_reg);
181 }
182
183 static void __exit xt_rateest_tg_fini(void)
184 {
185         xt_unregister_target(&xt_rateest_tg_reg);
186 }
187
188
189 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
190 MODULE_LICENSE("GPL");
191 MODULE_DESCRIPTION("Xtables: packet rate estimator");
192 MODULE_ALIAS("ipt_RATEEST");
193 MODULE_ALIAS("ip6t_RATEEST");
194 module_init(xt_rateest_tg_init);
195 module_exit(xt_rateest_tg_fini);