Merge branch 'forbid-goto_chain-fallback'
[muen/linux.git] / net / sched / act_police.c
1 /*
2  * net/sched/act_police.c       Input police filter
3  *
4  *              This program is free software; you can redistribute it and/or
5  *              modify it under the terms of the GNU General Public License
6  *              as published by the Free Software Foundation; either version
7  *              2 of the License, or (at your option) any later version.
8  *
9  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10  *              J Hadi Salim (action changes)
11  */
12
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
18 #include <linux/skbuff.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <net/act_api.h>
23 #include <net/netlink.h>
24
25 struct tcf_police_params {
26         int                     tcfp_result;
27         u32                     tcfp_ewma_rate;
28         s64                     tcfp_burst;
29         u32                     tcfp_mtu;
30         s64                     tcfp_toks;
31         s64                     tcfp_ptoks;
32         s64                     tcfp_mtu_ptoks;
33         s64                     tcfp_t_c;
34         struct psched_ratecfg   rate;
35         bool                    rate_present;
36         struct psched_ratecfg   peak;
37         bool                    peak_present;
38         struct rcu_head rcu;
39 };
40
41 struct tcf_police {
42         struct tc_action        common;
43         struct tcf_police_params __rcu *params;
44 };
45
46 #define to_police(pc) ((struct tcf_police *)pc)
47
48 /* old policer structure from before tc actions */
49 struct tc_police_compat {
50         u32                     index;
51         int                     action;
52         u32                     limit;
53         u32                     burst;
54         u32                     mtu;
55         struct tc_ratespec      rate;
56         struct tc_ratespec      peakrate;
57 };
58
59 /* Each policer is serialized by its individual spinlock */
60
61 static unsigned int police_net_id;
62 static struct tc_action_ops act_police_ops;
63
64 static int tcf_police_walker(struct net *net, struct sk_buff *skb,
65                                  struct netlink_callback *cb, int type,
66                                  const struct tc_action_ops *ops,
67                                  struct netlink_ext_ack *extack)
68 {
69         struct tc_action_net *tn = net_generic(net, police_net_id);
70
71         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
72 }
73
74 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
75         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
76         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
77         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
78         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
79 };
80
81 static int tcf_police_init(struct net *net, struct nlattr *nla,
82                                struct nlattr *est, struct tc_action **a,
83                                int ovr, int bind, bool rtnl_held,
84                                struct netlink_ext_ack *extack)
85 {
86         int ret = 0, err;
87         struct nlattr *tb[TCA_POLICE_MAX + 1];
88         struct tc_police *parm;
89         struct tcf_police *police;
90         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
91         struct tc_action_net *tn = net_generic(net, police_net_id);
92         struct tcf_police_params *new;
93         bool exists = false;
94         int size;
95
96         if (nla == NULL)
97                 return -EINVAL;
98
99         err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy, NULL);
100         if (err < 0)
101                 return err;
102
103         if (tb[TCA_POLICE_TBF] == NULL)
104                 return -EINVAL;
105         size = nla_len(tb[TCA_POLICE_TBF]);
106         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
107                 return -EINVAL;
108
109         parm = nla_data(tb[TCA_POLICE_TBF]);
110         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
111         if (err < 0)
112                 return err;
113         exists = err;
114         if (exists && bind)
115                 return 0;
116
117         if (!exists) {
118                 ret = tcf_idr_create(tn, parm->index, NULL, a,
119                                      &act_police_ops, bind, true);
120                 if (ret) {
121                         tcf_idr_cleanup(tn, parm->index);
122                         return ret;
123                 }
124                 ret = ACT_P_CREATED;
125         } else if (!ovr) {
126                 tcf_idr_release(*a, bind);
127                 return -EEXIST;
128         }
129
130         police = to_police(*a);
131         if (parm->rate.rate) {
132                 err = -ENOMEM;
133                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE], NULL);
134                 if (R_tab == NULL)
135                         goto failure;
136
137                 if (parm->peakrate.rate) {
138                         P_tab = qdisc_get_rtab(&parm->peakrate,
139                                                tb[TCA_POLICE_PEAKRATE], NULL);
140                         if (P_tab == NULL)
141                                 goto failure;
142                 }
143         }
144
145         if (est) {
146                 err = gen_replace_estimator(&police->tcf_bstats,
147                                             police->common.cpu_bstats,
148                                             &police->tcf_rate_est,
149                                             &police->tcf_lock,
150                                             NULL, est);
151                 if (err)
152                         goto failure;
153         } else if (tb[TCA_POLICE_AVRATE] &&
154                    (ret == ACT_P_CREATED ||
155                     !gen_estimator_active(&police->tcf_rate_est))) {
156                 err = -EINVAL;
157                 goto failure;
158         }
159
160         new = kzalloc(sizeof(*new), GFP_KERNEL);
161         if (unlikely(!new)) {
162                 err = -ENOMEM;
163                 goto failure;
164         }
165
166         /* No failure allowed after this point */
167         new->tcfp_mtu = parm->mtu;
168         if (!new->tcfp_mtu) {
169                 new->tcfp_mtu = ~0;
170                 if (R_tab)
171                         new->tcfp_mtu = 255 << R_tab->rate.cell_log;
172         }
173         if (R_tab) {
174                 new->rate_present = true;
175                 psched_ratecfg_precompute(&new->rate, &R_tab->rate, 0);
176                 qdisc_put_rtab(R_tab);
177         } else {
178                 new->rate_present = false;
179         }
180         if (P_tab) {
181                 new->peak_present = true;
182                 psched_ratecfg_precompute(&new->peak, &P_tab->rate, 0);
183                 qdisc_put_rtab(P_tab);
184         } else {
185                 new->peak_present = false;
186         }
187
188         new->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
189         new->tcfp_toks = new->tcfp_burst;
190         if (new->peak_present) {
191                 new->tcfp_mtu_ptoks = (s64)psched_l2t_ns(&new->peak,
192                                                          new->tcfp_mtu);
193                 new->tcfp_ptoks = new->tcfp_mtu_ptoks;
194         }
195
196         if (tb[TCA_POLICE_AVRATE])
197                 new->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
198
199         if (tb[TCA_POLICE_RESULT]) {
200                 new->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
201                 if (TC_ACT_EXT_CMP(new->tcfp_result, TC_ACT_GOTO_CHAIN)) {
202                         NL_SET_ERR_MSG(extack,
203                                        "goto chain not allowed on fallback");
204                         err = -EINVAL;
205                         goto failure;
206                 }
207         }
208
209         spin_lock_bh(&police->tcf_lock);
210         new->tcfp_t_c = ktime_get_ns();
211         police->tcf_action = parm->action;
212         rcu_swap_protected(police->params,
213                            new,
214                            lockdep_is_held(&police->tcf_lock));
215         spin_unlock_bh(&police->tcf_lock);
216
217         if (new)
218                 kfree_rcu(new, rcu);
219
220         if (ret == ACT_P_CREATED)
221                 tcf_idr_insert(tn, *a);
222         return ret;
223
224 failure:
225         qdisc_put_rtab(P_tab);
226         qdisc_put_rtab(R_tab);
227         tcf_idr_release(*a, bind);
228         return err;
229 }
230
231 static int tcf_police_act(struct sk_buff *skb, const struct tc_action *a,
232                           struct tcf_result *res)
233 {
234         struct tcf_police *police = to_police(a);
235         struct tcf_police_params *p;
236         s64 now, toks, ptoks = 0;
237         int ret;
238
239         tcf_lastuse_update(&police->tcf_tm);
240         bstats_cpu_update(this_cpu_ptr(police->common.cpu_bstats), skb);
241
242         ret = READ_ONCE(police->tcf_action);
243         p = rcu_dereference_bh(police->params);
244
245         if (p->tcfp_ewma_rate) {
246                 struct gnet_stats_rate_est64 sample;
247
248                 if (!gen_estimator_read(&police->tcf_rate_est, &sample) ||
249                     sample.bps >= p->tcfp_ewma_rate)
250                         goto inc_overlimits;
251         }
252
253         if (qdisc_pkt_len(skb) <= p->tcfp_mtu) {
254                 if (!p->rate_present) {
255                         ret = p->tcfp_result;
256                         goto end;
257                 }
258
259                 now = ktime_get_ns();
260                 toks = min_t(s64, now - p->tcfp_t_c, p->tcfp_burst);
261                 if (p->peak_present) {
262                         ptoks = toks + p->tcfp_ptoks;
263                         if (ptoks > p->tcfp_mtu_ptoks)
264                                 ptoks = p->tcfp_mtu_ptoks;
265                         ptoks -= (s64)psched_l2t_ns(&p->peak,
266                                                     qdisc_pkt_len(skb));
267                 }
268                 toks += p->tcfp_toks;
269                 if (toks > p->tcfp_burst)
270                         toks = p->tcfp_burst;
271                 toks -= (s64)psched_l2t_ns(&p->rate, qdisc_pkt_len(skb));
272                 if ((toks|ptoks) >= 0) {
273                         p->tcfp_t_c = now;
274                         p->tcfp_toks = toks;
275                         p->tcfp_ptoks = ptoks;
276                         ret = p->tcfp_result;
277                         goto inc_drops;
278                 }
279         }
280
281 inc_overlimits:
282         qstats_overlimit_inc(this_cpu_ptr(police->common.cpu_qstats));
283 inc_drops:
284         if (ret == TC_ACT_SHOT)
285                 qstats_drop_inc(this_cpu_ptr(police->common.cpu_qstats));
286 end:
287         return ret;
288 }
289
290 static void tcf_police_cleanup(struct tc_action *a)
291 {
292         struct tcf_police *police = to_police(a);
293         struct tcf_police_params *p;
294
295         p = rcu_dereference_protected(police->params, 1);
296         if (p)
297                 kfree_rcu(p, rcu);
298 }
299
300 static int tcf_police_dump(struct sk_buff *skb, struct tc_action *a,
301                                int bind, int ref)
302 {
303         unsigned char *b = skb_tail_pointer(skb);
304         struct tcf_police *police = to_police(a);
305         struct tcf_police_params *p;
306         struct tc_police opt = {
307                 .index = police->tcf_index,
308                 .refcnt = refcount_read(&police->tcf_refcnt) - ref,
309                 .bindcnt = atomic_read(&police->tcf_bindcnt) - bind,
310         };
311         struct tcf_t t;
312
313         spin_lock_bh(&police->tcf_lock);
314         opt.action = police->tcf_action;
315         p = rcu_dereference_protected(police->params,
316                                       lockdep_is_held(&police->tcf_lock));
317         opt.mtu = p->tcfp_mtu;
318         opt.burst = PSCHED_NS2TICKS(p->tcfp_burst);
319         if (p->rate_present)
320                 psched_ratecfg_getrate(&opt.rate, &p->rate);
321         if (p->peak_present)
322                 psched_ratecfg_getrate(&opt.peakrate, &p->peak);
323         if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
324                 goto nla_put_failure;
325         if (p->tcfp_result &&
326             nla_put_u32(skb, TCA_POLICE_RESULT, p->tcfp_result))
327                 goto nla_put_failure;
328         if (p->tcfp_ewma_rate &&
329             nla_put_u32(skb, TCA_POLICE_AVRATE, p->tcfp_ewma_rate))
330                 goto nla_put_failure;
331
332         t.install = jiffies_to_clock_t(jiffies - police->tcf_tm.install);
333         t.lastuse = jiffies_to_clock_t(jiffies - police->tcf_tm.lastuse);
334         t.firstuse = jiffies_to_clock_t(jiffies - police->tcf_tm.firstuse);
335         t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
336         if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
337                 goto nla_put_failure;
338         spin_unlock_bh(&police->tcf_lock);
339
340         return skb->len;
341
342 nla_put_failure:
343         spin_unlock_bh(&police->tcf_lock);
344         nlmsg_trim(skb, b);
345         return -1;
346 }
347
348 static int tcf_police_search(struct net *net, struct tc_action **a, u32 index)
349 {
350         struct tc_action_net *tn = net_generic(net, police_net_id);
351
352         return tcf_idr_search(tn, a, index);
353 }
354
355 MODULE_AUTHOR("Alexey Kuznetsov");
356 MODULE_DESCRIPTION("Policing actions");
357 MODULE_LICENSE("GPL");
358
359 static struct tc_action_ops act_police_ops = {
360         .kind           =       "police",
361         .type           =       TCA_ID_POLICE,
362         .owner          =       THIS_MODULE,
363         .act            =       tcf_police_act,
364         .dump           =       tcf_police_dump,
365         .init           =       tcf_police_init,
366         .walk           =       tcf_police_walker,
367         .lookup         =       tcf_police_search,
368         .cleanup        =       tcf_police_cleanup,
369         .size           =       sizeof(struct tcf_police),
370 };
371
372 static __net_init int police_init_net(struct net *net)
373 {
374         struct tc_action_net *tn = net_generic(net, police_net_id);
375
376         return tc_action_net_init(tn, &act_police_ops);
377 }
378
379 static void __net_exit police_exit_net(struct list_head *net_list)
380 {
381         tc_action_net_exit(net_list, police_net_id);
382 }
383
384 static struct pernet_operations police_net_ops = {
385         .init = police_init_net,
386         .exit_batch = police_exit_net,
387         .id   = &police_net_id,
388         .size = sizeof(struct tc_action_net),
389 };
390
391 static int __init police_init_module(void)
392 {
393         return tcf_register_action(&act_police_ops, &police_net_ops);
394 }
395
396 static void __exit police_cleanup_module(void)
397 {
398         tcf_unregister_action(&act_police_ops, &police_net_ops);
399 }
400
401 module_init(police_init_module);
402 module_exit(police_cleanup_module);