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 28 static unsigned int xt_rateest_hash(const char *name) 29 { 30 return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) & 31 (RATEEST_HSIZE - 1); 32 } 33 34 static void xt_rateest_hash_insert(struct xt_rateest *est) 35 { 36 unsigned int h; 37 38 h = xt_rateest_hash(est->name); 39 hlist_add_head(&est->list, &rateest_hash[h]); 40 } 41 42 static struct xt_rateest *__xt_rateest_lookup(const char *name) 43 { 44 struct xt_rateest *est; 45 unsigned int h; 46 47 h = xt_rateest_hash(name); 48 hlist_for_each_entry(est, &rateest_hash[h], list) { 49 if (strcmp(est->name, name) == 0) { 50 est->refcnt++; 51 return est; 52 } 53 } 54 55 return NULL; 56 } 57 58 struct xt_rateest *xt_rateest_lookup(const char *name) 59 { 60 struct xt_rateest *est; 61 62 mutex_lock(&xt_rateest_mutex); 63 est = __xt_rateest_lookup(name); 64 mutex_unlock(&xt_rateest_mutex); 65 return est; 66 } 67 EXPORT_SYMBOL_GPL(xt_rateest_lookup); 68 69 void xt_rateest_put(struct xt_rateest *est) 70 { 71 mutex_lock(&xt_rateest_mutex); 72 if (--est->refcnt == 0) { 73 hlist_del(&est->list); 74 gen_kill_estimator(&est->rate_est); 75 /* 76 * gen_estimator est_timer() might access est->lock or bstats, 77 * wait a RCU grace period before freeing 'est' 78 */ 79 kfree_rcu(est, rcu); 80 } 81 mutex_unlock(&xt_rateest_mutex); 82 } 83 EXPORT_SYMBOL_GPL(xt_rateest_put); 84 85 static unsigned int 86 xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) 87 { 88 const struct xt_rateest_target_info *info = par->targinfo; 89 struct gnet_stats_basic_packed *stats = &info->est->bstats; 90 91 spin_lock_bh(&info->est->lock); 92 stats->bytes += skb->len; 93 stats->packets++; 94 spin_unlock_bh(&info->est->lock); 95 96 return XT_CONTINUE; 97 } 98 99 static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) 100 { 101 struct xt_rateest_target_info *info = par->targinfo; 102 struct xt_rateest *est; 103 struct { 104 struct nlattr opt; 105 struct gnet_estimator est; 106 } cfg; 107 int ret; 108 109 net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); 110 111 mutex_lock(&xt_rateest_mutex); 112 est = __xt_rateest_lookup(info->name); 113 if (est) { 114 mutex_unlock(&xt_rateest_mutex); 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); 123 return -EINVAL; 124 } 125 info->est = est; 126 return 0; 127 } 128 129 ret = -ENOMEM; 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; 139 140 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); 141 cfg.opt.nla_type = TCA_STATS_RATE_EST; 142 cfg.est.interval = info->interval; 143 cfg.est.ewma_log = info->ewma_log; 144 145 ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est, 146 &est->lock, NULL, &cfg.opt); 147 if (ret < 0) 148 goto err2; 149 150 info->est = est; 151 xt_rateest_hash_insert(est); 152 mutex_unlock(&xt_rateest_mutex); 153 return 0; 154 155 err2: 156 kfree(est); 157 err1: 158 mutex_unlock(&xt_rateest_mutex); 159 return ret; 160 } 161 162 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) 163 { 164 struct xt_rateest_target_info *info = par->targinfo; 165 166 xt_rateest_put(info->est); 167 } 168 169 static struct xt_target xt_rateest_tg_reg __read_mostly = { 170 .name = "RATEEST", 171 .revision = 0, 172 .family = NFPROTO_UNSPEC, 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 .usersize = offsetof(struct xt_rateest_target_info, est), 178 .me = THIS_MODULE, 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 return xt_register_target(&xt_rateest_tg_reg); 189 } 190 191 static void __exit xt_rateest_tg_fini(void) 192 { 193 xt_unregister_target(&xt_rateest_tg_reg); 194 } 195 196 197 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 198 MODULE_LICENSE("GPL"); 199 MODULE_DESCRIPTION("Xtables: packet rate estimator"); 200 MODULE_ALIAS("ipt_RATEEST"); 201 MODULE_ALIAS("ip6t_RATEEST"); 202 module_init(xt_rateest_tg_init); 203 module_exit(xt_rateest_tg_fini); 204