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
xt_rateest_hash(const char * name)31 static unsigned int xt_rateest_hash(const char *name)
32 {
33 return jhash(name, sizeof_field(struct xt_rateest, name), jhash_rnd) &
34 (RATEEST_HSIZE - 1);
35 }
36
xt_rateest_hash_insert(struct xt_rateest_net * xn,struct xt_rateest * est)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
__xt_rateest_lookup(struct xt_rateest_net * xn,const char * name)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
xt_rateest_lookup(struct net * net,const char * name)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
xt_rateest_put(struct net * net,struct xt_rateest * est)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
xt_rateest_tg(struct sk_buff * skb,const struct xt_action_param * par)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_sync *stats = &info->est->bstats;
98
99 spin_lock_bh(&info->est->lock);
100 u64_stats_add(&stats->bytes, skb->len);
101 u64_stats_inc(&stats->packets);
102 spin_unlock_bh(&info->est->lock);
103
104 return XT_CONTINUE;
105 }
106
xt_rateest_tg_checkentry(const struct xt_tgchk_param * par)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 if (strnlen(info->name, sizeof(est->name)) >= sizeof(est->name))
119 return -ENAMETOOLONG;
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 gnet_stats_basic_sync_init(&est->bstats);
147 strscpy(est->name, info->name, sizeof(est->name));
148 spin_lock_init(&est->lock);
149 est->refcnt = 1;
150 est->params.interval = info->interval;
151 est->params.ewma_log = info->ewma_log;
152
153 cfg.opt.nla_len = nla_attr_size(sizeof(cfg.est));
154 cfg.opt.nla_type = TCA_STATS_RATE_EST;
155 cfg.est.interval = info->interval;
156 cfg.est.ewma_log = info->ewma_log;
157
158 ret = gen_new_estimator(&est->bstats, NULL, &est->rate_est,
159 &est->lock, NULL, &cfg.opt);
160 if (ret < 0)
161 goto err2;
162
163 info->est = est;
164 xt_rateest_hash_insert(xn, est);
165 mutex_unlock(&xn->hash_lock);
166 return 0;
167
168 err2:
169 kfree(est);
170 err1:
171 mutex_unlock(&xn->hash_lock);
172 return ret;
173 }
174
xt_rateest_tg_destroy(const struct xt_tgdtor_param * par)175 static void xt_rateest_tg_destroy(const struct xt_tgdtor_param *par)
176 {
177 struct xt_rateest_target_info *info = par->targinfo;
178
179 xt_rateest_put(par->net, info->est);
180 }
181
182 static struct xt_target xt_rateest_tg_reg[] __read_mostly = {
183 {
184 .name = "RATEEST",
185 .revision = 0,
186 .family = NFPROTO_IPV4,
187 .target = xt_rateest_tg,
188 .checkentry = xt_rateest_tg_checkentry,
189 .destroy = xt_rateest_tg_destroy,
190 .targetsize = sizeof(struct xt_rateest_target_info),
191 .usersize = offsetof(struct xt_rateest_target_info, est),
192 .me = THIS_MODULE,
193 },
194 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
195 {
196 .name = "RATEEST",
197 .revision = 0,
198 .family = NFPROTO_IPV6,
199 .target = xt_rateest_tg,
200 .checkentry = xt_rateest_tg_checkentry,
201 .destroy = xt_rateest_tg_destroy,
202 .targetsize = sizeof(struct xt_rateest_target_info),
203 .usersize = offsetof(struct xt_rateest_target_info, est),
204 .me = THIS_MODULE,
205 },
206 #endif
207 };
208
xt_rateest_net_init(struct net * net)209 static __net_init int xt_rateest_net_init(struct net *net)
210 {
211 struct xt_rateest_net *xn = net_generic(net, xt_rateest_id);
212 int i;
213
214 mutex_init(&xn->hash_lock);
215 for (i = 0; i < ARRAY_SIZE(xn->hash); i++)
216 INIT_HLIST_HEAD(&xn->hash[i]);
217 return 0;
218 }
219
220 static struct pernet_operations xt_rateest_net_ops = {
221 .init = xt_rateest_net_init,
222 .id = &xt_rateest_id,
223 .size = sizeof(struct xt_rateest_net),
224 };
225
xt_rateest_tg_init(void)226 static int __init xt_rateest_tg_init(void)
227 {
228 int err = register_pernet_subsys(&xt_rateest_net_ops);
229
230 if (err)
231 return err;
232 return xt_register_targets(xt_rateest_tg_reg, ARRAY_SIZE(xt_rateest_tg_reg));
233 }
234
xt_rateest_tg_fini(void)235 static void __exit xt_rateest_tg_fini(void)
236 {
237 xt_unregister_targets(xt_rateest_tg_reg, ARRAY_SIZE(xt_rateest_tg_reg));
238 unregister_pernet_subsys(&xt_rateest_net_ops);
239 }
240
241
242 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
243 MODULE_LICENSE("GPL");
244 MODULE_DESCRIPTION("Xtables: packet rate estimator");
245 MODULE_ALIAS("ipt_RATEEST");
246 MODULE_ALIAS("ip6t_RATEEST");
247 module_init(xt_rateest_tg_init);
248 module_exit(xt_rateest_tg_fini);
249