1 /* 2 * (C) 2007 Patrick McHardy <[email protected]> 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 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 mutex_lock(&xt_rateest_mutex); 49 hlist_for_each_entry(est, &rateest_hash[h], list) { 50 if (strcmp(est->name, name) == 0) { 51 est->refcnt++; 52 mutex_unlock(&xt_rateest_mutex); 53 return est; 54 } 55 } 56 mutex_unlock(&xt_rateest_mutex); 57 return NULL; 58 } 59 EXPORT_SYMBOL_GPL(xt_rateest_lookup); 60 61 void xt_rateest_put(struct xt_rateest *est) 62 { 63 mutex_lock(&xt_rateest_mutex); 64 if (--est->refcnt == 0) { 65 hlist_del(&est->list); 66 gen_kill_estimator(&est->rate_est); 67 /* 68 * gen_estimator est_timer() might access est->lock or bstats, 69 * wait a RCU grace period before freeing 'est' 70 */ 71 kfree_rcu(est, rcu); 72 } 73 mutex_unlock(&xt_rateest_mutex); 74 } 75 EXPORT_SYMBOL_GPL(xt_rateest_put); 76 77 static unsigned int 78 xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) 79 { 80 const struct xt_rateest_target_info *info = par->targinfo; 81 struct gnet_stats_basic_packed *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 int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) 92 { 93 struct xt_rateest_target_info *info = par->targinfo; 94 struct xt_rateest *est; 95 struct { 96 struct nlattr opt; 97 struct gnet_estimator est; 98 } cfg; 99 int ret; 100 101 net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); 102 103 est = xt_rateest_lookup(info->name); 104 if (est) { 105 /* 106 * If estimator parameters are specified, they must match the 107 * existing estimator. 108 */ 109 if ((!info->interval && !info->ewma_log) || 110 (info->interval != est->params.interval || 111 info->ewma_log != est->params.ewma_log)) { 112 xt_rateest_put(est); 113 return -EINVAL; 114 } 115 info->est = est; 116 return 0; 117 } 118 119 ret = -ENOMEM; 120 est = kzalloc(sizeof(*est), GFP_KERNEL); 121 if (!est) 122 goto err1; 123 124 strlcpy(est->name, info->name, sizeof(est->name)); 125 spin_lock_init(&est->lock); 126 est->refcnt = 1; 127 est->params.interval = info->interval; 128 est->params.ewma_log = info->ewma_log; 129 130 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); 131 cfg.opt.nla_type = TCA_STATS_RATE_EST; 132 cfg.est.interval = info->interval; 133 cfg.est.ewma_log = info->ewma_log; 134 135 ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est, 136 &est->lock, NULL, &cfg.opt); 137 if (ret < 0) 138 goto err2; 139 140 info->est = est; 141 xt_rateest_hash_insert(est); 142 return 0; 143 144 err2: 145 kfree(est); 146 err1: 147 return ret; 148 } 149 150 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) 151 { 152 struct xt_rateest_target_info *info = par->targinfo; 153 154 xt_rateest_put(info->est); 155 } 156 157 static struct xt_target xt_rateest_tg_reg __read_mostly = { 158 .name = "RATEEST", 159 .revision = 0, 160 .family = NFPROTO_UNSPEC, 161 .target = xt_rateest_tg, 162 .checkentry = xt_rateest_tg_checkentry, 163 .destroy = xt_rateest_tg_destroy, 164 .targetsize = sizeof(struct xt_rateest_target_info), 165 .usersize = offsetof(struct xt_rateest_target_info, est), 166 .me = THIS_MODULE, 167 }; 168 169 static int __init xt_rateest_tg_init(void) 170 { 171 unsigned int i; 172 173 for (i = 0; i < ARRAY_SIZE(rateest_hash); i++) 174 INIT_HLIST_HEAD(&rateest_hash[i]); 175 176 return xt_register_target(&xt_rateest_tg_reg); 177 } 178 179 static void __exit xt_rateest_tg_fini(void) 180 { 181 xt_unregister_target(&xt_rateest_tg_reg); 182 } 183 184 185 MODULE_AUTHOR("Patrick McHardy <[email protected]>"); 186 MODULE_LICENSE("GPL"); 187 MODULE_DESCRIPTION("Xtables: packet rate estimator"); 188 MODULE_ALIAS("ipt_RATEEST"); 189 MODULE_ALIAS("ip6t_RATEEST"); 190 module_init(xt_rateest_tg_init); 191 module_exit(xt_rateest_tg_fini); 192