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 unsigned int h; 47 48 h = xt_rateest_hash(name); 49 mutex_lock(&xt_rateest_mutex); 50 hlist_for_each_entry(est, &rateest_hash[h], list) { 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); 68 /* 69 * gen_estimator est_timer() might access est->lock or bstats, 70 * wait a RCU grace period before freeing 'est' 71 */ 72 kfree_rcu(est, rcu); 73 } 74 mutex_unlock(&xt_rateest_mutex); 75 } 76 EXPORT_SYMBOL_GPL(xt_rateest_put); 77 78 static unsigned int 79 xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) 80 { 81 const struct xt_rateest_target_info *info = par->targinfo; 82 struct gnet_stats_basic_packed *stats = &info->est->bstats; 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 92 static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) 93 { 94 struct xt_rateest_target_info *info = par->targinfo; 95 struct xt_rateest *est; 96 struct { 97 struct nlattr opt; 98 struct gnet_estimator est; 99 } cfg; 100 int ret; 101 102 if (unlikely(!rnd_inited)) { 103 get_random_bytes(&jhash_rnd, sizeof(jhash_rnd)); 104 rnd_inited = true; 105 } 106 107 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); 117 return -EINVAL; 118 } 119 info->est = est; 120 return 0; 121 } 122 123 ret = -ENOMEM; 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; 133 134 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); 135 cfg.opt.nla_type = TCA_STATS_RATE_EST; 136 cfg.est.interval = info->interval; 137 cfg.est.ewma_log = info->ewma_log; 138 139 ret = gen_new_estimator(&est->bstats, NULL, &est->rstats, 140 &est->lock, NULL, &cfg.opt); 141 if (ret < 0) 142 goto err2; 143 144 info->est = est; 145 xt_rateest_hash_insert(est); 146 return 0; 147 148 err2: 149 kfree(est); 150 err1: 151 return ret; 152 } 153 154 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) 155 { 156 struct xt_rateest_target_info *info = par->targinfo; 157 158 xt_rateest_put(info->est); 159 } 160 161 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, 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]); 178 179 return xt_register_target(&xt_rateest_tg_reg); 180 } 181 182 static void __exit xt_rateest_tg_fini(void) 183 { 184 xt_unregister_target(&xt_rateest_tg_reg); 185 } 186 187 188 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 189 MODULE_LICENSE("GPL"); 190 MODULE_DESCRIPTION("Xtables: packet rate estimator"); 191 MODULE_ALIAS("ipt_RATEEST"); 192 MODULE_ALIAS("ip6t_RATEEST"); 193 module_init(xt_rateest_tg_init); 194 module_exit(xt_rateest_tg_fini); 195