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 #include <net/netns/generic.h> 18 19 #include <linux/netfilter/x_tables.h> 20 #include <linux/netfilter/xt_RATEEST.h> 21 #include <net/netfilter/xt_rateest.h> 22 23 #define RATEEST_HSIZE 16 24 25 struct xt_rateest_net { 26 struct mutex hash_lock; 27 struct hlist_head hash[RATEEST_HSIZE]; 28 }; 29 30 static unsigned int xt_rateest_id; 31 32 static unsigned int jhash_rnd __read_mostly; 33 34 static unsigned int xt_rateest_hash(const char *name) 35 { 36 return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) & 37 (RATEEST_HSIZE - 1); 38 } 39 40 static void xt_rateest_hash_insert(struct xt_rateest_net *xn, 41 struct xt_rateest *est) 42 { 43 unsigned int h; 44 45 h = xt_rateest_hash(est->name); 46 hlist_add_head(&est->list, &xn->hash[h]); 47 } 48 49 static struct xt_rateest *__xt_rateest_lookup(struct xt_rateest_net *xn, 50 const char *name) 51 { 52 struct xt_rateest *est; 53 unsigned int h; 54 55 h = xt_rateest_hash(name); 56 hlist_for_each_entry(est, &xn->hash[h], list) { 57 if (strcmp(est->name, name) == 0) { 58 est->refcnt++; 59 return est; 60 } 61 } 62 63 return NULL; 64 } 65 66 struct xt_rateest *xt_rateest_lookup(struct net *net, const char *name) 67 { 68 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 69 struct xt_rateest *est; 70 71 mutex_lock(&xn->hash_lock); 72 est = __xt_rateest_lookup(xn, name); 73 mutex_unlock(&xn->hash_lock); 74 return est; 75 } 76 EXPORT_SYMBOL_GPL(xt_rateest_lookup); 77 78 void xt_rateest_put(struct net *net, struct xt_rateest *est) 79 { 80 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 81 82 mutex_lock(&xn->hash_lock); 83 if (--est->refcnt == 0) { 84 hlist_del(&est->list); 85 gen_kill_estimator(&est->rate_est); 86 /* 87 * gen_estimator est_timer() might access est->lock or bstats, 88 * wait a RCU grace period before freeing 'est' 89 */ 90 kfree_rcu(est, rcu); 91 } 92 mutex_unlock(&xn->hash_lock); 93 } 94 EXPORT_SYMBOL_GPL(xt_rateest_put); 95 96 static unsigned int 97 xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) 98 { 99 const struct xt_rateest_target_info *info = par->targinfo; 100 struct gnet_stats_basic_packed *stats = &info->est->bstats; 101 102 spin_lock_bh(&info->est->lock); 103 stats->bytes += skb->len; 104 stats->packets++; 105 spin_unlock_bh(&info->est->lock); 106 107 return XT_CONTINUE; 108 } 109 110 static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) 111 { 112 struct xt_rateest_net *xn = net_generic(par->net, xt_rateest_id); 113 struct xt_rateest_target_info *info = par->targinfo; 114 struct xt_rateest *est; 115 struct { 116 struct nlattr opt; 117 struct gnet_estimator est; 118 } cfg; 119 int ret; 120 121 net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); 122 123 mutex_lock(&xn->hash_lock); 124 est = __xt_rateest_lookup(xn, info->name); 125 if (est) { 126 mutex_unlock(&xn->hash_lock); 127 /* 128 * If estimator parameters are specified, they must match the 129 * existing estimator. 130 */ 131 if ((!info->interval && !info->ewma_log) || 132 (info->interval != est->params.interval || 133 info->ewma_log != est->params.ewma_log)) { 134 xt_rateest_put(par->net, est); 135 return -EINVAL; 136 } 137 info->est = est; 138 return 0; 139 } 140 141 ret = -ENOMEM; 142 est = kzalloc(sizeof(*est), GFP_KERNEL); 143 if (!est) 144 goto err1; 145 146 strlcpy(est->name, info->name, sizeof(est->name)); 147 spin_lock_init(&est->lock); 148 est->refcnt = 1; 149 est->params.interval = info->interval; 150 est->params.ewma_log = info->ewma_log; 151 152 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); 153 cfg.opt.nla_type = TCA_STATS_RATE_EST; 154 cfg.est.interval = info->interval; 155 cfg.est.ewma_log = info->ewma_log; 156 157 ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est, 158 &est->lock, NULL, &cfg.opt); 159 if (ret < 0) 160 goto err2; 161 162 info->est = est; 163 xt_rateest_hash_insert(xn, est); 164 mutex_unlock(&xn->hash_lock); 165 return 0; 166 167 err2: 168 kfree(est); 169 err1: 170 mutex_unlock(&xn->hash_lock); 171 return ret; 172 } 173 174 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) 175 { 176 struct xt_rateest_target_info *info = par->targinfo; 177 178 xt_rateest_put(par->net, info->est); 179 } 180 181 static struct xt_target xt_rateest_tg_reg __read_mostly = { 182 .name = "RATEEST", 183 .revision = 0, 184 .family = NFPROTO_UNSPEC, 185 .target = xt_rateest_tg, 186 .checkentry = xt_rateest_tg_checkentry, 187 .destroy = xt_rateest_tg_destroy, 188 .targetsize = sizeof(struct xt_rateest_target_info), 189 .usersize = offsetof(struct xt_rateest_target_info, est), 190 .me = THIS_MODULE, 191 }; 192 193 static __net_init int xt_rateest_net_init(struct net *net) 194 { 195 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 196 int i; 197 198 mutex_init(&xn->hash_lock); 199 for (i = 0; i < ARRAY_SIZE(xn->hash); i++) 200 INIT_HLIST_HEAD(&xn->hash[i]); 201 return 0; 202 } 203 204 static void __net_exit xt_rateest_net_exit(struct net *net) 205 { 206 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 207 int i; 208 209 for (i = 0; i < ARRAY_SIZE(xn->hash); i++) 210 WARN_ON_ONCE(!hlist_empty(&xn->hash[i])); 211 } 212 213 static struct pernet_operations xt_rateest_net_ops = { 214 .init = xt_rateest_net_init, 215 .exit = xt_rateest_net_exit, 216 .id = &xt_rateest_id, 217 .size = sizeof(struct xt_rateest_net), 218 }; 219 220 static int __init xt_rateest_tg_init(void) 221 { 222 int err = register_pernet_subsys(&xt_rateest_net_ops); 223 224 if (err) 225 return err; 226 return xt_register_target(&xt_rateest_tg_reg); 227 } 228 229 static void __exit xt_rateest_tg_fini(void) 230 { 231 xt_unregister_target(&xt_rateest_tg_reg); 232 unregister_pernet_subsys(&xt_rateest_net_ops); 233 } 234 235 236 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 237 MODULE_LICENSE("GPL"); 238 MODULE_DESCRIPTION("Xtables: packet rate estimator"); 239 MODULE_ALIAS("ipt_RATEEST"); 240 MODULE_ALIAS("ip6t_RATEEST"); 241 module_init(xt_rateest_tg_init); 242 module_exit(xt_rateest_tg_fini); 243