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 {
  26         struct tc_action        common;
  27         int                     tcfp_result;
  28         u32                     tcfp_ewma_rate;
  29         s64                     tcfp_burst;
  30         u32                     tcfp_mtu;
  31         s64                     tcfp_toks;
  32         s64                     tcfp_ptoks;
  33         s64                     tcfp_mtu_ptoks;
  34         s64                     tcfp_t_c;
  35         struct psched_ratecfg   rate;
  36         bool                    rate_present;
  37         struct psched_ratecfg   peak;
  38         bool                    peak_present;
  39 };
  40
  41 #define to_police(pc) ((struct tcf_police *)pc)
  42
  43 /* old policer structure from before tc actions */
  44 struct tc_police_compat {
  45         u32                     index;
  46         int                     action;
  47         u32                     limit;
  48         u32                     burst;
  49         u32                     mtu;
  50         struct tc_ratespec      rate;
  51         struct tc_ratespec      peakrate;
  52 };
  53
  54 /* Each policer is serialized by its individual spinlock */
  55
  56 static unsigned int police_net_id;
  57 static struct tc_action_ops act_police_ops;
  58
  59 static int tcf_act_police_walker(struct net *net, struct sk_buff *skb,
  60                                  struct netlink_callback *cb, int type,
  61                                  const struct tc_action_ops *ops)
  62 {
  63         struct tc_action_net *tn = net_generic(net, police_net_id);
  64
  65         return tcf_generic_walker(tn, skb, cb, type, ops);
  66 }
  67
  68 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
  69         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
  70         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
  71         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
  72         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
  73 };
  74
  75 static int tcf_act_police_init(struct net *net, struct nlattr *nla,
  76                                struct nlattr *est, struct tc_action **a,
  77                                int ovr, int bind)
  78 {
  79         int ret = 0, err;
  80         struct nlattr *tb[TCA_POLICE_MAX + 1];
  81         struct tc_police *parm;
  82         struct tcf_police *police;
  83         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
  84         struct tc_action_net *tn = net_generic(net, police_net_id);
  85         bool exists = false;
  86         int size;
  87
  88         if (nla == NULL)
  89                 return -EINVAL;
  90
  91         err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy, NULL);
  92         if (err < 0)
  93                 return err;
  94
  95         if (tb[TCA_POLICE_TBF] == NULL)
  96                 return -EINVAL;
  97         size = nla_len(tb[TCA_POLICE_TBF]);
  98         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
  99                 return -EINVAL;
 100
 101         parm = nla_data(tb[TCA_POLICE_TBF]);
 102         exists = tcf_idr_check(tn, parm->index, a, bind);
 103         if (exists && bind)
 104                 return 0;
 105
 106         if (!exists) {
 107                 ret = tcf_idr_create(tn, parm->index, NULL, a,
 108                                      &act_police_ops, bind, false);
 109                 if (ret)
 110                         return ret;
 111                 ret = ACT_P_CREATED;
 112         } else {
 113                 tcf_idr_release(*a, bind);
 114                 if (!ovr)
 115                         return -EEXIST;
 116         }
 117
 118         police = to_police(*a);
 119         if (parm->rate.rate) {
 120                 err = -ENOMEM;
 121                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
 122                 if (R_tab == NULL)
 123                         goto failure;
 124
 125                 if (parm->peakrate.rate) {
 126                         P_tab = qdisc_get_rtab(&parm->peakrate,
 127                                                tb[TCA_POLICE_PEAKRATE]);
 128                         if (P_tab == NULL)
 129                                 goto failure;
 130                 }
 131         }
 132
 133         if (est) {
 134                 err = gen_replace_estimator(&police->tcf_bstats, NULL,
 135                                             &police->tcf_rate_est,
 136                                             &police->tcf_lock,
 137                                             NULL, est);
 138                 if (err)
 139                         goto failure;
 140         } else if (tb[TCA_POLICE_AVRATE] &&
 141                    (ret == ACT_P_CREATED ||
 142                     !gen_estimator_active(&police->tcf_rate_est))) {
 143                 err = -EINVAL;
 144                 goto failure;
 145         }
 146
 147         spin_lock_bh(&police->tcf_lock);
 148         /* No failure allowed after this point */
 149         police->tcfp_mtu = parm->mtu;
 150         if (police->tcfp_mtu == 0) {
 151                 police->tcfp_mtu = ~0;
 152                 if (R_tab)
 153                         police->tcfp_mtu = 255 << R_tab->rate.cell_log;
 154         }
 155         if (R_tab) {
 156                 police->rate_present = true;
 157                 psched_ratecfg_precompute(&police->rate, &R_tab->rate, 0);
 158                 qdisc_put_rtab(R_tab);
 159         } else {
 160                 police->rate_present = false;
 161         }
 162         if (P_tab) {
 163                 police->peak_present = true;
 164                 psched_ratecfg_precompute(&police->peak, &P_tab->rate, 0);
 165                 qdisc_put_rtab(P_tab);
 166         } else {
 167                 police->peak_present = false;
 168         }
 169
 170         if (tb[TCA_POLICE_RESULT])
 171                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 172         police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
 173         police->tcfp_toks = police->tcfp_burst;
 174         if (police->peak_present) {
 175                 police->tcfp_mtu_ptoks = (s64) psched_l2t_ns(&police->peak,
 176                                                              police->tcfp_mtu);
 177                 police->tcfp_ptoks = police->tcfp_mtu_ptoks;
 178         }
 179         police->tcf_action = parm->action;
 180
 181         if (tb[TCA_POLICE_AVRATE])
 182                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 183
 184         spin_unlock_bh(&police->tcf_lock);
 185         if (ret != ACT_P_CREATED)
 186                 return ret;
 187
 188         police->tcfp_t_c = ktime_get_ns();
 189         tcf_idr_insert(tn, *a);
 190
 191         return ret;
 192
 193 failure:
 194         qdisc_put_rtab(P_tab);
 195         qdisc_put_rtab(R_tab);
 196         if (ret == ACT_P_CREATED)
 197                 tcf_idr_release(*a, bind);
 198         return err;
 199 }
 200
 201 static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 202                           struct tcf_result *res)
 203 {
 204         struct tcf_police *police = to_police(a);
 205         s64 now;
 206         s64 toks;
 207         s64 ptoks = 0;
 208
 209         spin_lock(&police->tcf_lock);
 210
 211         bstats_update(&police->tcf_bstats, skb);
 212         tcf_lastuse_update(&police->tcf_tm);
 213
 214         if (police->tcfp_ewma_rate) {
 215                 struct gnet_stats_rate_est64 sample;
 216
 217                 if (!gen_estimator_read(&police->tcf_rate_est, &sample) ||
 218                     sample.bps >= police->tcfp_ewma_rate) {
 219                         police->tcf_qstats.overlimits++;
 220                         if (police->tcf_action == TC_ACT_SHOT)
 221                                 police->tcf_qstats.drops++;
 222                         spin_unlock(&police->tcf_lock);
 223                         return police->tcf_action;
 224                 }
 225         }
 226
 227         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 228                 if (!police->rate_present) {
 229                         spin_unlock(&police->tcf_lock);
 230                         return police->tcfp_result;
 231                 }
 232
 233                 now = ktime_get_ns();
 234                 toks = min_t(s64, now - police->tcfp_t_c,
 235                              police->tcfp_burst);
 236                 if (police->peak_present) {
 237                         ptoks = toks + police->tcfp_ptoks;
 238                         if (ptoks > police->tcfp_mtu_ptoks)
 239                                 ptoks = police->tcfp_mtu_ptoks;
 240                         ptoks -= (s64) psched_l2t_ns(&police->peak,
 241                                                      qdisc_pkt_len(skb));
 242                 }
 243                 toks += police->tcfp_toks;
 244                 if (toks > police->tcfp_burst)
 245                         toks = police->tcfp_burst;
 246                 toks -= (s64) psched_l2t_ns(&police->rate, qdisc_pkt_len(skb));
 247                 if ((toks|ptoks) >= 0) {
 248                         police->tcfp_t_c = now;
 249                         police->tcfp_toks = toks;
 250                         police->tcfp_ptoks = ptoks;
 251                         if (police->tcfp_result == TC_ACT_SHOT)
 252                                 police->tcf_qstats.drops++;
 253                         spin_unlock(&police->tcf_lock);
 254                         return police->tcfp_result;
 255                 }
 256         }
 257
 258         police->tcf_qstats.overlimits++;
 259         if (police->tcf_action == TC_ACT_SHOT)
 260                 police->tcf_qstats.drops++;
 261         spin_unlock(&police->tcf_lock);
 262         return police->tcf_action;
 263 }
 264
 265 static int tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a,
 266                                int bind, int ref)
 267 {
 268         unsigned char *b = skb_tail_pointer(skb);
 269         struct tcf_police *police = to_police(a);
 270         struct tc_police opt = {
 271                 .index = police->tcf_index,
 272                 .action = police->tcf_action,
 273                 .mtu = police->tcfp_mtu,
 274                 .burst = PSCHED_NS2TICKS(police->tcfp_burst),
 275                 .refcnt = police->tcf_refcnt - ref,
 276                 .bindcnt = police->tcf_bindcnt - bind,
 277         };
 278         struct tcf_t t;
 279
 280         if (police->rate_present)
 281                 psched_ratecfg_getrate(&opt.rate, &police->rate);
 282         if (police->peak_present)
 283                 psched_ratecfg_getrate(&opt.peakrate, &police->peak);
 284         if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
 285                 goto nla_put_failure;
 286         if (police->tcfp_result &&
 287             nla_put_u32(skb, TCA_POLICE_RESULT, police->tcfp_result))
 288                 goto nla_put_failure;
 289         if (police->tcfp_ewma_rate &&
 290             nla_put_u32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate))
 291                 goto nla_put_failure;
 292
 293         t.install = jiffies_to_clock_t(jiffies - police->tcf_tm.install);
 294         t.lastuse = jiffies_to_clock_t(jiffies - police->tcf_tm.lastuse);
 295         t.firstuse = jiffies_to_clock_t(jiffies - police->tcf_tm.firstuse);
 296         t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
 297         if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
 298                 goto nla_put_failure;
 299
 300         return skb->len;
 301
 302 nla_put_failure:
 303         nlmsg_trim(skb, b);
 304         return -1;
 305 }
 306
 307 static int tcf_police_search(struct net *net, struct tc_action **a, u32 index)
 308 {
 309         struct tc_action_net *tn = net_generic(net, police_net_id);
 310
 311         return tcf_idr_search(tn, a, index);
 312 }
 313
 314 MODULE_AUTHOR("Alexey Kuznetsov");
 315 MODULE_DESCRIPTION("Policing actions");
 316 MODULE_LICENSE("GPL");
 317
 318 static struct tc_action_ops act_police_ops = {
 319         .kind           =       "police",
 320         .type           =       TCA_ID_POLICE,
 321         .owner          =       THIS_MODULE,
 322         .act            =       tcf_act_police,
 323         .dump           =       tcf_act_police_dump,
 324         .init           =       tcf_act_police_init,
 325         .walk           =       tcf_act_police_walker,
 326         .lookup         =       tcf_police_search,
 327         .size           =       sizeof(struct tcf_police),
 328 };
 329
 330 static __net_init int police_init_net(struct net *net)
 331 {
 332         struct tc_action_net *tn = net_generic(net, police_net_id);
 333
 334         return tc_action_net_init(tn, &act_police_ops);
 335 }
 336
 337 static void __net_exit police_exit_net(struct net *net)
 338 {
 339         struct tc_action_net *tn = net_generic(net, police_net_id);
 340
 341         tc_action_net_exit(tn);
 342 }
 343
 344 static struct pernet_operations police_net_ops = {
 345         .init = police_init_net,
 346         .exit = police_exit_net,
 347         .id   = &police_net_id,
 348         .size = sizeof(struct tc_action_net),
 349 };
 350
 351 static int __init police_init_module(void)
 352 {
 353         return tcf_register_action(&act_police_ops, &police_net_ops);
 354 }
 355
 356 static void __exit police_cleanup_module(void)
 357 {
 358         tcf_unregister_action(&act_police_ops, &police_net_ops);
 359 }
 360
 361 module_init(police_init_module);
 362 module_exit(police_cleanup_module);