whiterose

linux unikernel
Log | Files | Refs | README | LICENSE | git clone https://git.ne02ptzero.me/git/whiterose

xt_RATEEST.c (5695B)


      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 struct pernet_operations xt_rateest_net_ops = {
    205 	.init = xt_rateest_net_init,
    206 	.id   = &xt_rateest_id,
    207 	.size = sizeof(struct xt_rateest_net),
    208 };
    209 
    210 static int __init xt_rateest_tg_init(void)
    211 {
    212 	int err = register_pernet_subsys(&xt_rateest_net_ops);
    213 
    214 	if (err)
    215 		return err;
    216 	return xt_register_target(&xt_rateest_tg_reg);
    217 }
    218 
    219 static void __exit xt_rateest_tg_fini(void)
    220 {
    221 	xt_unregister_target(&xt_rateest_tg_reg);
    222 	unregister_pernet_subsys(&xt_rateest_net_ops);
    223 }
    224 
    225 
    226 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
    227 MODULE_LICENSE("GPL");
    228 MODULE_DESCRIPTION("Xtables: packet rate estimator");
    229 MODULE_ALIAS("ipt_RATEEST");
    230 MODULE_ALIAS("ip6t_RATEEST");
    231 module_init(xt_rateest_tg_init);
    232 module_exit(xt_rateest_tg_fini);