| 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, &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); |