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 #define POL_TAB_MASK     15
  44
  45 /* old policer structure from before tc actions */
  46 struct tc_police_compat {
  47         u32                     index;
  48         int                     action;
  49         u32                     limit;
  50         u32                     burst;
  51         u32                     mtu;
  52         struct tc_ratespec      rate;
  53         struct tc_ratespec      peakrate;
  54 };
  55
  56 /* Each policer is serialized by its individual spinlock */
  57
  58 static unsigned int police_net_id;
  59 static struct tc_action_ops act_police_ops;
  60
  61 static int tcf_act_police_walker(struct net *net, struct sk_buff *skb,
  62                                  struct netlink_callback *cb, int type,
  63                                  const struct tc_action_ops *ops)
  64 {
  65         struct tc_action_net *tn = net_generic(net, police_net_id);
  66
  67         return tcf_generic_walker(tn, skb, cb, type, ops);
  68 }
  69
  70 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
  71         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
  72         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
  73         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
  74         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
  75 };
  76
  77 static int tcf_act_police_init(struct net *net, struct nlattr *nla,
  78                                struct nlattr *est, struct tc_action **a,
  79                                int ovr, int bind)
  80 {
  81         int ret = 0, err;
  82         struct nlattr *tb[TCA_POLICE_MAX + 1];
  83         struct tc_police *parm;
  84         struct tcf_police *police;
  85         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
  86         struct tc_action_net *tn = net_generic(net, police_net_id);
  87         bool exists = false;
  88         int size;
  89
  90         if (nla == NULL)
  91                 return -EINVAL;
  92
  93         err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy);
  94         if (err < 0)
  95                 return err;
  96
  97         if (tb[TCA_POLICE_TBF] == NULL)
  98                 return -EINVAL;
  99         size = nla_len(tb[TCA_POLICE_TBF]);
 100         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
 101                 return -EINVAL;
 102
 103         parm = nla_data(tb[TCA_POLICE_TBF]);
 104         exists = tcf_hash_check(tn, parm->index, a, bind);
 105         if (exists && bind)
 106                 return 0;
 107
 108         if (!exists) {
 109                 ret = tcf_hash_create(tn, parm->index, NULL, a,
 110                                       &act_police_ops, bind, false);
 111                 if (ret)
 112                         return ret;
 113                 ret = ACT_P_CREATED;
 114         } else {
 115                 tcf_hash_release(*a, bind);
 116                 if (!ovr)
 117                         return -EEXIST;
 118         }
 119
 120         police = to_police(*a);
 121         if (parm->rate.rate) {
 122                 err = -ENOMEM;
 123                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
 124                 if (R_tab == NULL)
 125                         goto failure;
 126
 127                 if (parm->peakrate.rate) {
 128                         P_tab = qdisc_get_rtab(&parm->peakrate,
 129                                                tb[TCA_POLICE_PEAKRATE]);
 130                         if (P_tab == NULL)
 131                                 goto failure;
 132                 }
 133         }
 134
 135         spin_lock_bh(&police->tcf_lock);
 136         if (est) {
 137                 err = gen_replace_estimator(&police->tcf_bstats, NULL,
 138                                             &police->tcf_rate_est,
 139                                             &police->tcf_lock,
 140                                             NULL, est);
 141                 if (err)
 142                         goto failure_unlock;
 143         } else if (tb[TCA_POLICE_AVRATE] &&
 144                    (ret == ACT_P_CREATED ||
 145                     !gen_estimator_active(&police->tcf_rate_est))) {
 146                 err = -EINVAL;
 147                 goto failure_unlock;
 148         }
 149
 150         /* No failure allowed after this point */
 151         police->tcfp_mtu = parm->mtu;
 152         if (police->tcfp_mtu == 0) {
 153                 police->tcfp_mtu = ~0;
 154                 if (R_tab)
 155                         police->tcfp_mtu = 255 << R_tab->rate.cell_log;
 156         }
 157         if (R_tab) {
 158                 police->rate_present = true;
 159                 psched_ratecfg_precompute(&police->rate, &R_tab->rate, 0);
 160                 qdisc_put_rtab(R_tab);
 161         } else {
 162                 police->rate_present = false;
 163         }
 164         if (P_tab) {
 165                 police->peak_present = true;
 166                 psched_ratecfg_precompute(&police->peak, &P_tab->rate, 0);
 167                 qdisc_put_rtab(P_tab);
 168         } else {
 169                 police->peak_present = false;
 170         }
 171
 172         if (tb[TCA_POLICE_RESULT])
 173                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 174         police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
 175         police->tcfp_toks = police->tcfp_burst;
 176         if (police->peak_present) {
 177                 police->tcfp_mtu_ptoks = (s64) psched_l2t_ns(&police->peak,
 178                                                              police->tcfp_mtu);
 179                 police->tcfp_ptoks = police->tcfp_mtu_ptoks;
 180         }
 181         police->tcf_action = parm->action;
 182
 183         if (tb[TCA_POLICE_AVRATE])
 184                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 185
 186         spin_unlock_bh(&police->tcf_lock);
 187         if (ret != ACT_P_CREATED)
 188                 return ret;
 189
 190         police->tcfp_t_c = ktime_get_ns();
 191         tcf_hash_insert(tn, *a);
 192
 193         return ret;
 194
 195 failure_unlock:
 196         spin_unlock_bh(&police->tcf_lock);
 197 failure:
 198         qdisc_put_rtab(P_tab);
 199         qdisc_put_rtab(R_tab);
 200         if (ret == ACT_P_CREATED)
 201                 tcf_hash_cleanup(*a, est);
 202         return err;
 203 }
 204
 205 static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 206                           struct tcf_result *res)
 207 {
 208         struct tcf_police *police = to_police(a);
 209         s64 now;
 210         s64 toks;
 211         s64 ptoks = 0;
 212
 213         spin_lock(&police->tcf_lock);
 214
 215         bstats_update(&police->tcf_bstats, skb);
 216         tcf_lastuse_update(&police->tcf_tm);
 217
 218         if (police->tcfp_ewma_rate) {
 219                 struct gnet_stats_rate_est64 sample;
 220
 221                 if (!gen_estimator_read(&police->tcf_rate_est, &sample) ||
 222                     sample.bps >= police->tcfp_ewma_rate) {
 223                         police->tcf_qstats.overlimits++;
 224                         if (police->tcf_action == TC_ACT_SHOT)
 225                                 police->tcf_qstats.drops++;
 226                         spin_unlock(&police->tcf_lock);
 227                         return police->tcf_action;
 228                 }
 229         }
 230
 231         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 232                 if (!police->rate_present) {
 233                         spin_unlock(&police->tcf_lock);
 234                         return police->tcfp_result;
 235                 }
 236
 237                 now = ktime_get_ns();
 238                 toks = min_t(s64, now - police->tcfp_t_c,
 239                              police->tcfp_burst);
 240                 if (police->peak_present) {
 241                         ptoks = toks + police->tcfp_ptoks;
 242                         if (ptoks > police->tcfp_mtu_ptoks)
 243                                 ptoks = police->tcfp_mtu_ptoks;
 244                         ptoks -= (s64) psched_l2t_ns(&police->peak,
 245                                                      qdisc_pkt_len(skb));
 246                 }
 247                 toks += police->tcfp_toks;
 248                 if (toks > police->tcfp_burst)
 249                         toks = police->tcfp_burst;
 250                 toks -= (s64) psched_l2t_ns(&police->rate, qdisc_pkt_len(skb));
 251                 if ((toks|ptoks) >= 0) {
 252                         police->tcfp_t_c = now;
 253                         police->tcfp_toks = toks;
 254                         police->tcfp_ptoks = ptoks;
 255                         if (police->tcfp_result == TC_ACT_SHOT)
 256                                 police->tcf_qstats.drops++;
 257                         spin_unlock(&police->tcf_lock);
 258                         return police->tcfp_result;
 259                 }
 260         }
 261
 262         police->tcf_qstats.overlimits++;
 263         if (police->tcf_action == TC_ACT_SHOT)
 264                 police->tcf_qstats.drops++;
 265         spin_unlock(&police->tcf_lock);
 266         return police->tcf_action;
 267 }
 268
 269 static int tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a,
 270                                int bind, int ref)
 271 {
 272         unsigned char *b = skb_tail_pointer(skb);
 273         struct tcf_police *police = to_police(a);
 274         struct tc_police opt = {
 275                 .index = police->tcf_index,
 276                 .action = police->tcf_action,
 277                 .mtu = police->tcfp_mtu,
 278                 .burst = PSCHED_NS2TICKS(police->tcfp_burst),
 279                 .refcnt = police->tcf_refcnt - ref,
 280                 .bindcnt = police->tcf_bindcnt - bind,
 281         };
 282         struct tcf_t t;
 283
 284         if (police->rate_present)
 285                 psched_ratecfg_getrate(&opt.rate, &police->rate);
 286         if (police->peak_present)
 287                 psched_ratecfg_getrate(&opt.peakrate, &police->peak);
 288         if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
 289                 goto nla_put_failure;
 290         if (police->tcfp_result &&
 291             nla_put_u32(skb, TCA_POLICE_RESULT, police->tcfp_result))
 292                 goto nla_put_failure;
 293         if (police->tcfp_ewma_rate &&
 294             nla_put_u32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate))
 295                 goto nla_put_failure;
 296
 297         t.install = jiffies_to_clock_t(jiffies - police->tcf_tm.install);
 298         t.lastuse = jiffies_to_clock_t(jiffies - police->tcf_tm.lastuse);
 299         t.firstuse = jiffies_to_clock_t(jiffies - police->tcf_tm.firstuse);
 300         t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
 301         if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
 302                 goto nla_put_failure;
 303
 304         return skb->len;
 305
 306 nla_put_failure:
 307         nlmsg_trim(skb, b);
 308         return -1;
 309 }
 310
 311 static int tcf_police_search(struct net *net, struct tc_action **a, u32 index)
 312 {
 313         struct tc_action_net *tn = net_generic(net, police_net_id);
 314
 315         return tcf_hash_search(tn, a, index);
 316 }
 317
 318 MODULE_AUTHOR("Alexey Kuznetsov");
 319 MODULE_DESCRIPTION("Policing actions");
 320 MODULE_LICENSE("GPL");
 321
 322 static struct tc_action_ops act_police_ops = {
 323         .kind           =       "police",
 324         .type           =       TCA_ID_POLICE,
 325         .owner          =       THIS_MODULE,
 326         .act            =       tcf_act_police,
 327         .dump           =       tcf_act_police_dump,
 328         .init           =       tcf_act_police_init,
 329         .walk           =       tcf_act_police_walker,
 330         .lookup         =       tcf_police_search,
 331         .size           =       sizeof(struct tcf_police),
 332 };
 333
 334 static __net_init int police_init_net(struct net *net)
 335 {
 336         struct tc_action_net *tn = net_generic(net, police_net_id);
 337
 338         return tc_action_net_init(tn, &act_police_ops, POL_TAB_MASK);
 339 }
 340
 341 static void __net_exit police_exit_net(struct net *net)
 342 {
 343         struct tc_action_net *tn = net_generic(net, police_net_id);
 344
 345         tc_action_net_exit(tn);
 346 }
 347
 348 static struct pernet_operations police_net_ops = {
 349         .init = police_init_net,
 350         .exit = police_exit_net,
 351         .id   = &police_net_id,
 352         .size = sizeof(struct tc_action_net),
 353 };
 354
 355 static int __init police_init_module(void)
 356 {
 357         return tcf_register_action(&act_police_ops, &police_net_ops);
 358 }
 359
 360 static void __exit police_cleanup_module(void)
 361 {
 362         tcf_unregister_action(&act_police_ops, &police_net_ops);
 363 }
 364
 365 module_init(police_init_module);
 366 module_exit(police_cleanup_module);