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_police_walker(struct net *net, struct sk_buff *skb,
  60                                  struct netlink_callback *cb, int type,
  61                                  const struct tc_action_ops *ops,
  62                                  struct netlink_ext_ack *extack)
  63 {
  64         struct tc_action_net *tn = net_generic(net, police_net_id);
  65
  66         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
  67 }
  68
  69 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
  70         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
  71         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
  72         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
  73         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
  74 };
  75
  76 static int tcf_police_init(struct net *net, struct nlattr *nla,
  77                                struct nlattr *est, struct tc_action **a,
  78                                int ovr, int bind, bool rtnl_held,
  79                                struct netlink_ext_ack *extack)
  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, NULL);
  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         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 105         if (err < 0)
 106                 return err;
 107         exists = err;
 108         if (exists && bind)
 109                 return 0;
 110
 111         if (!exists) {
 112                 ret = tcf_idr_create(tn, parm->index, NULL, a,
 113                                      &act_police_ops, bind, false);
 114                 if (ret) {
 115                         tcf_idr_cleanup(tn, parm->index);
 116                         return ret;
 117                 }
 118                 ret = ACT_P_CREATED;
 119         } else if (!ovr) {
 120                 tcf_idr_release(*a, bind);
 121                 return -EEXIST;
 122         }
 123
 124         police = to_police(*a);
 125         if (parm->rate.rate) {
 126                 err = -ENOMEM;
 127                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE], NULL);
 128                 if (R_tab == NULL)
 129                         goto failure;
 130
 131                 if (parm->peakrate.rate) {
 132                         P_tab = qdisc_get_rtab(&parm->peakrate,
 133                                                tb[TCA_POLICE_PEAKRATE], NULL);
 134                         if (P_tab == NULL)
 135                                 goto failure;
 136                 }
 137         }
 138
 139         if (est) {
 140                 err = gen_replace_estimator(&police->tcf_bstats, NULL,
 141                                             &police->tcf_rate_est,
 142                                             &police->tcf_lock,
 143                                             NULL, est);
 144                 if (err)
 145                         goto failure;
 146         } else if (tb[TCA_POLICE_AVRATE] &&
 147                    (ret == ACT_P_CREATED ||
 148                     !gen_estimator_active(&police->tcf_rate_est))) {
 149                 err = -EINVAL;
 150                 goto failure;
 151         }
 152
 153         spin_lock_bh(&police->tcf_lock);
 154         /* No failure allowed after this point */
 155         police->tcfp_mtu = parm->mtu;
 156         if (police->tcfp_mtu == 0) {
 157                 police->tcfp_mtu = ~0;
 158                 if (R_tab)
 159                         police->tcfp_mtu = 255 << R_tab->rate.cell_log;
 160         }
 161         if (R_tab) {
 162                 police->rate_present = true;
 163                 psched_ratecfg_precompute(&police->rate, &R_tab->rate, 0);
 164                 qdisc_put_rtab(R_tab);
 165         } else {
 166                 police->rate_present = false;
 167         }
 168         if (P_tab) {
 169                 police->peak_present = true;
 170                 psched_ratecfg_precompute(&police->peak, &P_tab->rate, 0);
 171                 qdisc_put_rtab(P_tab);
 172         } else {
 173                 police->peak_present = false;
 174         }
 175
 176         if (tb[TCA_POLICE_RESULT])
 177                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 178         police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
 179         police->tcfp_toks = police->tcfp_burst;
 180         if (police->peak_present) {
 181                 police->tcfp_mtu_ptoks = (s64) psched_l2t_ns(&police->peak,
 182                                                              police->tcfp_mtu);
 183                 police->tcfp_ptoks = police->tcfp_mtu_ptoks;
 184         }
 185         police->tcf_action = parm->action;
 186
 187         if (tb[TCA_POLICE_AVRATE])
 188                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 189
 190         spin_unlock_bh(&police->tcf_lock);
 191         if (ret != ACT_P_CREATED)
 192                 return ret;
 193
 194         police->tcfp_t_c = ktime_get_ns();
 195         tcf_idr_insert(tn, *a);
 196
 197         return ret;
 198
 199 failure:
 200         qdisc_put_rtab(P_tab);
 201         qdisc_put_rtab(R_tab);
 202         tcf_idr_release(*a, bind);
 203         return err;
 204 }
 205
 206 static int tcf_police_act(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                 struct gnet_stats_rate_est64 sample;
 221
 222                 if (!gen_estimator_read(&police->tcf_rate_est, &sample) ||
 223                     sample.bps >= police->tcfp_ewma_rate) {
 224                         police->tcf_qstats.overlimits++;
 225                         if (police->tcf_action == TC_ACT_SHOT)
 226                                 police->tcf_qstats.drops++;
 227                         spin_unlock(&police->tcf_lock);
 228                         return police->tcf_action;
 229                 }
 230         }
 231
 232         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 233                 if (!police->rate_present) {
 234                         spin_unlock(&police->tcf_lock);
 235                         return police->tcfp_result;
 236                 }
 237
 238                 now = ktime_get_ns();
 239                 toks = min_t(s64, now - police->tcfp_t_c,
 240                              police->tcfp_burst);
 241                 if (police->peak_present) {
 242                         ptoks = toks + police->tcfp_ptoks;
 243                         if (ptoks > police->tcfp_mtu_ptoks)
 244                                 ptoks = police->tcfp_mtu_ptoks;
 245                         ptoks -= (s64) psched_l2t_ns(&police->peak,
 246                                                      qdisc_pkt_len(skb));
 247                 }
 248                 toks += police->tcfp_toks;
 249                 if (toks > police->tcfp_burst)
 250                         toks = police->tcfp_burst;
 251                 toks -= (s64) psched_l2t_ns(&police->rate, qdisc_pkt_len(skb));
 252                 if ((toks|ptoks) >= 0) {
 253                         police->tcfp_t_c = now;
 254                         police->tcfp_toks = toks;
 255                         police->tcfp_ptoks = ptoks;
 256                         if (police->tcfp_result == TC_ACT_SHOT)
 257                                 police->tcf_qstats.drops++;
 258                         spin_unlock(&police->tcf_lock);
 259                         return police->tcfp_result;
 260                 }
 261         }
 262
 263         police->tcf_qstats.overlimits++;
 264         if (police->tcf_action == TC_ACT_SHOT)
 265                 police->tcf_qstats.drops++;
 266         spin_unlock(&police->tcf_lock);
 267         return police->tcf_action;
 268 }
 269
 270 static int tcf_police_dump(struct sk_buff *skb, struct tc_action *a,
 271                                int bind, int ref)
 272 {
 273         unsigned char *b = skb_tail_pointer(skb);
 274         struct tcf_police *police = to_police(a);
 275         struct tc_police opt = {
 276                 .index = police->tcf_index,
 277                 .refcnt = refcount_read(&police->tcf_refcnt) - ref,
 278                 .bindcnt = atomic_read(&police->tcf_bindcnt) - bind,
 279         };
 280         struct tcf_t t;
 281
 282         spin_lock_bh(&police->tcf_lock);
 283         opt.action = police->tcf_action;
 284         opt.mtu = police->tcfp_mtu;
 285         opt.burst = PSCHED_NS2TICKS(police->tcfp_burst);
 286         if (police->rate_present)
 287                 psched_ratecfg_getrate(&opt.rate, &police->rate);
 288         if (police->peak_present)
 289                 psched_ratecfg_getrate(&opt.peakrate, &police->peak);
 290         if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
 291                 goto nla_put_failure;
 292         if (police->tcfp_result &&
 293             nla_put_u32(skb, TCA_POLICE_RESULT, police->tcfp_result))
 294                 goto nla_put_failure;
 295         if (police->tcfp_ewma_rate &&
 296             nla_put_u32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate))
 297                 goto nla_put_failure;
 298
 299         t.install = jiffies_to_clock_t(jiffies - police->tcf_tm.install);
 300         t.lastuse = jiffies_to_clock_t(jiffies - police->tcf_tm.lastuse);
 301         t.firstuse = jiffies_to_clock_t(jiffies - police->tcf_tm.firstuse);
 302         t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
 303         if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
 304                 goto nla_put_failure;
 305         spin_unlock_bh(&police->tcf_lock);
 306
 307         return skb->len;
 308
 309 nla_put_failure:
 310         spin_unlock_bh(&police->tcf_lock);
 311         nlmsg_trim(skb, b);
 312         return -1;
 313 }
 314
 315 static int tcf_police_search(struct net *net, struct tc_action **a, u32 index,
 316                              struct netlink_ext_ack *extack)
 317 {
 318         struct tc_action_net *tn = net_generic(net, police_net_id);
 319
 320         return tcf_idr_search(tn, a, index);
 321 }
 322
 323 MODULE_AUTHOR("Alexey Kuznetsov");
 324 MODULE_DESCRIPTION("Policing actions");
 325 MODULE_LICENSE("GPL");
 326
 327 static struct tc_action_ops act_police_ops = {
 328         .kind           =       "police",
 329         .type           =       TCA_ID_POLICE,
 330         .owner          =       THIS_MODULE,
 331         .act            =       tcf_police_act,
 332         .dump           =       tcf_police_dump,
 333         .init           =       tcf_police_init,
 334         .walk           =       tcf_police_walker,
 335         .lookup         =       tcf_police_search,
 336         .size           =       sizeof(struct tcf_police),
 337 };
 338
 339 static __net_init int police_init_net(struct net *net)
 340 {
 341         struct tc_action_net *tn = net_generic(net, police_net_id);
 342
 343         return tc_action_net_init(tn, &act_police_ops);
 344 }
 345
 346 static void __net_exit police_exit_net(struct list_head *net_list)
 347 {
 348         tc_action_net_exit(net_list, police_net_id);
 349 }
 350
 351 static struct pernet_operations police_net_ops = {
 352         .init = police_init_net,
 353         .exit_batch = police_exit_net,
 354         .id   = &police_net_id,
 355         .size = sizeof(struct tc_action_net),
 356 };
 357
 358 static int __init police_init_module(void)
 359 {
 360         return tcf_register_action(&act_police_ops, &police_net_ops);
 361 }
 362
 363 static void __exit police_cleanup_module(void)
 364 {
 365         tcf_unregister_action(&act_police_ops, &police_net_ops);
 366 }
 367
 368 module_init(police_init_module);
 369 module_exit(police_cleanup_module);