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 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_bstats,
 146                                           &police->tcf_rate_est))) {
 147                 err = -EINVAL;
 148                 goto failure_unlock;
 149         }
 150
 151         /* No failure allowed after this point */
 152         police->tcfp_mtu = parm->mtu;
 153         if (police->tcfp_mtu == 0) {
 154                 police->tcfp_mtu = ~0;
 155                 if (R_tab)
 156                         police->tcfp_mtu = 255 << R_tab->rate.cell_log;
 157         }
 158         if (R_tab) {
 159                 police->rate_present = true;
 160                 psched_ratecfg_precompute(&police->rate, &R_tab->rate, 0);
 161                 qdisc_put_rtab(R_tab);
 162         } else {
 163                 police->rate_present = false;
 164         }
 165         if (P_tab) {
 166                 police->peak_present = true;
 167                 psched_ratecfg_precompute(&police->peak, &P_tab->rate, 0);
 168                 qdisc_put_rtab(P_tab);
 169         } else {
 170                 police->peak_present = false;
 171         }
 172
 173         if (tb[TCA_POLICE_RESULT])
 174                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 175         police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
 176         police->tcfp_toks = police->tcfp_burst;
 177         if (police->peak_present) {
 178                 police->tcfp_mtu_ptoks = (s64) psched_l2t_ns(&police->peak,
 179                                                              police->tcfp_mtu);
 180                 police->tcfp_ptoks = police->tcfp_mtu_ptoks;
 181         }
 182         police->tcf_action = parm->action;
 183
 184         if (tb[TCA_POLICE_AVRATE])
 185                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 186
 187         spin_unlock_bh(&police->tcf_lock);
 188         if (ret != ACT_P_CREATED)
 189                 return ret;
 190
 191         police->tcfp_t_c = ktime_get_ns();
 192         tcf_hash_insert(tn, *a);
 193
 194         return ret;
 195
 196 failure_unlock:
 197         spin_unlock_bh(&police->tcf_lock);
 198 failure:
 199         qdisc_put_rtab(P_tab);
 200         qdisc_put_rtab(R_tab);
 201         if (ret == ACT_P_CREATED)
 202                 tcf_hash_cleanup(*a, est);
 203         return err;
 204 }
 205
 206 static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 207                           struct tcf_result *res)
 208 {
 209         struct tcf_police *police = to_police(a);
 210         s64 now;
 211         s64 toks;
 212         s64 ptoks = 0;
 213
 214         spin_lock(&police->tcf_lock);
 215
 216         bstats_update(&police->tcf_bstats, skb);
 217         tcf_lastuse_update(&police->tcf_tm);
 218
 219         if (police->tcfp_ewma_rate &&
 220             police->tcf_rate_est.bps >= police->tcfp_ewma_rate) {
 221                 police->tcf_qstats.overlimits++;
 222                 if (police->tcf_action == TC_ACT_SHOT)
 223                         police->tcf_qstats.drops++;
 224                 spin_unlock(&police->tcf_lock);
 225                 return police->tcf_action;
 226         }
 227
 228         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 229                 if (!police->rate_present) {
 230                         spin_unlock(&police->tcf_lock);
 231                         return police->tcfp_result;
 232                 }
 233
 234                 now = ktime_get_ns();
 235                 toks = min_t(s64, now - police->tcfp_t_c,
 236                              police->tcfp_burst);
 237                 if (police->peak_present) {
 238                         ptoks = toks + police->tcfp_ptoks;
 239                         if (ptoks > police->tcfp_mtu_ptoks)
 240                                 ptoks = police->tcfp_mtu_ptoks;
 241                         ptoks -= (s64) psched_l2t_ns(&police->peak,
 242                                                      qdisc_pkt_len(skb));
 243                 }
 244                 toks += police->tcfp_toks;
 245                 if (toks > police->tcfp_burst)
 246                         toks = police->tcfp_burst;
 247                 toks -= (s64) psched_l2t_ns(&police->rate, qdisc_pkt_len(skb));
 248                 if ((toks|ptoks) >= 0) {
 249                         police->tcfp_t_c = now;
 250                         police->tcfp_toks = toks;
 251                         police->tcfp_ptoks = ptoks;
 252                         spin_unlock(&police->tcf_lock);
 253                         return police->tcfp_result;
 254                 }
 255         }
 256
 257         police->tcf_qstats.overlimits++;
 258         if (police->tcf_action == TC_ACT_SHOT)
 259                 police->tcf_qstats.drops++;
 260         spin_unlock(&police->tcf_lock);
 261         return police->tcf_action;
 262 }
 263
 264 static int
 265 tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 266 {
 267         unsigned char *b = skb_tail_pointer(skb);
 268         struct tcf_police *police = to_police(a);
 269         struct tc_police opt = {
 270                 .index = police->tcf_index,
 271                 .action = police->tcf_action,
 272                 .mtu = police->tcfp_mtu,
 273                 .burst = PSCHED_NS2TICKS(police->tcfp_burst),
 274                 .refcnt = police->tcf_refcnt - ref,
 275                 .bindcnt = police->tcf_bindcnt - bind,
 276         };
 277         struct tcf_t t;
 278
 279         if (police->rate_present)
 280                 psched_ratecfg_getrate(&opt.rate, &police->rate);
 281         if (police->peak_present)
 282                 psched_ratecfg_getrate(&opt.peakrate, &police->peak);
 283         if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
 284                 goto nla_put_failure;
 285         if (police->tcfp_result &&
 286             nla_put_u32(skb, TCA_POLICE_RESULT, police->tcfp_result))
 287                 goto nla_put_failure;
 288         if (police->tcfp_ewma_rate &&
 289             nla_put_u32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate))
 290                 goto nla_put_failure;
 291
 292         t.install = jiffies_to_clock_t(jiffies - police->tcf_tm.install);
 293         t.lastuse = jiffies_to_clock_t(jiffies - police->tcf_tm.lastuse);
 294         t.firstuse = jiffies_to_clock_t(jiffies - police->tcf_tm.firstuse);
 295         t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
 296         if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
 297                 goto nla_put_failure;
 298
 299         return skb->len;
 300
 301 nla_put_failure:
 302         nlmsg_trim(skb, b);
 303         return -1;
 304 }
 305
 306 static int tcf_police_search(struct net *net, struct tc_action **a, u32 index)
 307 {
 308         struct tc_action_net *tn = net_generic(net, police_net_id);
 309
 310         return tcf_hash_search(tn, a, index);
 311 }
 312
 313 MODULE_AUTHOR("Alexey Kuznetsov");
 314 MODULE_DESCRIPTION("Policing actions");
 315 MODULE_LICENSE("GPL");
 316
 317 static struct tc_action_ops act_police_ops = {
 318         .kind           =       "police",
 319         .type           =       TCA_ID_POLICE,
 320         .owner          =       THIS_MODULE,
 321         .act            =       tcf_act_police,
 322         .dump           =       tcf_act_police_dump,
 323         .init           =       tcf_act_police_init,
 324         .walk           =       tcf_act_police_walker,
 325         .lookup         =       tcf_police_search,
 326         .size           =       sizeof(struct tcf_police),
 327 };
 328
 329 static __net_init int police_init_net(struct net *net)
 330 {
 331         struct tc_action_net *tn = net_generic(net, police_net_id);
 332
 333         return tc_action_net_init(tn, &act_police_ops, POL_TAB_MASK);
 334 }
 335
 336 static void __net_exit police_exit_net(struct net *net)
 337 {
 338         struct tc_action_net *tn = net_generic(net, police_net_id);
 339
 340         tc_action_net_exit(tn);
 341 }
 342
 343 static struct pernet_operations police_net_ops = {
 344         .init = police_init_net,
 345         .exit = police_exit_net,
 346         .id   = &police_net_id,
 347         .size = sizeof(struct tc_action_net),
 348 };
 349
 350 static int __init
 351 police_init_module(void)
 352 {
 353         return tcf_register_action(&act_police_ops, &police_net_ops);
 354 }
 355
 356 static void __exit
 357 police_cleanup_module(void)
 358 {
 359         tcf_unregister_action(&act_police_ops, &police_net_ops);
 360 }
 361
 362 module_init(police_init_module);
 363 module_exit(police_cleanup_module);