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);