1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * (C) 2007 Patrick McHardy <kaber@trash.net> 4 */ 5 #include <linux/module.h> 6 #include <linux/skbuff.h> 7 #include <linux/gen_stats.h> 8 #include <linux/jhash.h> 9 #include <linux/rtnetlink.h> 10 #include <linux/random.h> 11 #include <linux/slab.h> 12 #include <net/gen_stats.h> 13 #include <net/netlink.h> 14 #include <net/netns/generic.h> 15 16 #include <linux/netfilter/x_tables.h> 17 #include <linux/netfilter/xt_RATEEST.h> 18 #include <net/netfilter/xt_rateest.h> 19 20 #define RATEEST_HSIZE 16 21 22 struct xt_rateest_net { 23 struct mutex hash_lock; 24 struct hlist_head hash[RATEEST_HSIZE]; 25 }; 26 27 static unsigned int xt_rateest_id; 28 29 static unsigned int jhash_rnd __read_mostly; 30 31 static unsigned int xt_rateest_hash(const char *name) 32 { 33 return jhash(name, FIELD_SIZEOF(struct xt_rateest, name), jhash_rnd) & 34 (RATEEST_HSIZE - 1); 35 } 36 37 static void xt_rateest_hash_insert(struct xt_rateest_net *xn, 38 struct xt_rateest *est) 39 { 40 unsigned int h; 41 42 h = xt_rateest_hash(est->name); 43 hlist_add_head(&est->list, &xn->hash[h]); 44 } 45 46 static struct xt_rateest *__xt_rateest_lookup(struct xt_rateest_net *xn, 47 const char *name) 48 { 49 struct xt_rateest *est; 50 unsigned int h; 51 52 h = xt_rateest_hash(name); 53 hlist_for_each_entry(est, &xn->hash[h], list) { 54 if (strcmp(est->name, name) == 0) { 55 est->refcnt++; 56 return est; 57 } 58 } 59 60 return NULL; 61 } 62 63 struct xt_rateest *xt_rateest_lookup(struct net *net, const char *name) 64 { 65 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 66 struct xt_rateest *est; 67 68 mutex_lock(&xn->hash_lock); 69 est = __xt_rateest_lookup(xn, name); 70 mutex_unlock(&xn->hash_lock); 71 return est; 72 } 73 EXPORT_SYMBOL_GPL(xt_rateest_lookup); 74 75 void xt_rateest_put(struct net *net, struct xt_rateest *est) 76 { 77 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 78 79 mutex_lock(&xn->hash_lock); 80 if (--est->refcnt == 0) { 81 hlist_del(&est->list); 82 gen_kill_estimator(&est->rate_est); 83 /* 84 * gen_estimator est_timer() might access est->lock or bstats, 85 * wait a RCU grace period before freeing 'est' 86 */ 87 kfree_rcu(est, rcu); 88 } 89 mutex_unlock(&xn->hash_lock); 90 } 91 EXPORT_SYMBOL_GPL(xt_rateest_put); 92 93 static unsigned int 94 xt_rateest_tg(struct sk_buff *skb, const struct xt_action_param *par) 95 { 96 const struct xt_rateest_target_info *info = par->targinfo; 97 struct gnet_stats_basic_packed *stats = &info->est->bstats; 98 99 spin_lock_bh(&info->est->lock); 100 stats->bytes += skb->len; 101 stats->packets++; 102 spin_unlock_bh(&info->est->lock); 103 104 return XT_CONTINUE; 105 } 106 107 static int xt_rateest_tg_checkentry(const struct xt_tgchk_param *par) 108 { 109 struct xt_rateest_net *xn = net_generic(par->net, xt_rateest_id); 110 struct xt_rateest_target_info *info = par->targinfo; 111 struct xt_rateest *est; 112 struct { 113 struct nlattr opt; 114 struct gnet_estimator est; 115 } cfg; 116 int ret; 117 118 net_get_random_once(&jhash_rnd, sizeof(jhash_rnd)); 119 120 mutex_lock(&xn->hash_lock); 121 est = __xt_rateest_lookup(xn, info->name); 122 if (est) { 123 mutex_unlock(&xn->hash_lock); 124 /* 125 * If estimator parameters are specified, they must match the 126 * existing estimator. 127 */ 128 if ((!info->interval && !info->ewma_log) || 129 (info->interval != est->params.interval || 130 info->ewma_log != est->params.ewma_log)) { 131 xt_rateest_put(par->net, est); 132 return -EINVAL; 133 } 134 info->est = est; 135 return 0; 136 } 137 138 ret = -ENOMEM; 139 est = kzalloc(sizeof(*est), GFP_KERNEL); 140 if (!est) 141 goto err1; 142 143 strlcpy(est->name, info->name, sizeof(est->name)); 144 spin_lock_init(&est->lock); 145 est->refcnt = 1; 146 est->params.interval = info->interval; 147 est->params.ewma_log = info->ewma_log; 148 149 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est)); 150 cfg.opt.nla_type = TCA_STATS_RATE_EST; 151 cfg.est.interval = info->interval; 152 cfg.est.ewma_log = info->ewma_log; 153 154 ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est, 155 &est->lock, NULL, &cfg.opt); 156 if (ret < 0) 157 goto err2; 158 159 info->est = est; 160 xt_rateest_hash_insert(xn, est); 161 mutex_unlock(&xn->hash_lock); 162 return 0; 163 164 err2: 165 kfree(est); 166 err1: 167 mutex_unlock(&xn->hash_lock); 168 return ret; 169 } 170 171 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par) 172 { 173 struct xt_rateest_target_info *info = par->targinfo; 174 175 xt_rateest_put(par->net, info->est); 176 } 177 178 static struct xt_target xt_rateest_tg_reg __read_mostly = { 179 .name = "RATEEST", 180 .revision = 0, 181 .family = NFPROTO_UNSPEC, 182 .target = xt_rateest_tg, 183 .checkentry = xt_rateest_tg_checkentry, 184 .destroy = xt_rateest_tg_destroy, 185 .targetsize = sizeof(struct xt_rateest_target_info), 186 .usersize = offsetof(struct xt_rateest_target_info, est), 187 .me = THIS_MODULE, 188 }; 189 190 static __net_init int xt_rateest_net_init(struct net *net) 191 { 192 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id); 193 int i; 194 195 mutex_init(&xn->hash_lock); 196 for (i = 0; i < ARRAY_SIZE(xn->hash); i++) 197 INIT_HLIST_HEAD(&xn->hash[i]); 198 return 0; 199 } 200 201 static struct pernet_operations xt_rateest_net_ops = { 202 .init = xt_rateest_net_init, 203 .id = &xt_rateest_id, 204 .size = sizeof(struct xt_rateest_net), 205 }; 206 207 static int __init xt_rateest_tg_init(void) 208 { 209 int err = register_pernet_subsys(&xt_rateest_net_ops); 210 211 if (err) 212 return err; 213 return xt_register_target(&xt_rateest_tg_reg); 214 } 215 216 static void __exit xt_rateest_tg_fini(void) 217 { 218 xt_unregister_target(&xt_rateest_tg_reg); 219 unregister_pernet_subsys(&xt_rateest_net_ops); 220 } 221 222 223 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 224 MODULE_LICENSE("GPL"); 225 MODULE_DESCRIPTION("Xtables: packet rate estimator"); 226 MODULE_ALIAS("ipt_RATEEST"); 227 MODULE_ALIAS("ip6t_RATEEST"); 228 module_init(xt_rateest_tg_init); 229 module_exit(xt_rateest_tg_fini); 230