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 tcf_common       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 #define to_police(pc)   \
  41         container_of(pc, struct tcf_police, common)
  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 tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb,
  59                               int type, struct tc_action *a)
  60 {
  61         struct tcf_hashinfo *hinfo = a->ops->hinfo;
  62         struct hlist_head *head;
  63         struct tcf_common *p;
  64         int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
  65         struct nlattr *nest;
  66
  67         spin_lock_bh(&hinfo->lock);
  68
  69         s_i = cb->args[0];
  70
  71         for (i = 0; i < (POL_TAB_MASK + 1); i++) {
  72                 head = &hinfo->htab[tcf_hash(i, POL_TAB_MASK)];
  73
  74                 hlist_for_each_entry_rcu(p, head, tcfc_head) {
  75                         index++;
  76                         if (index < s_i)
  77                                 continue;
  78                         a->priv = p;
  79                         a->order = index;
  80                         nest = nla_nest_start(skb, a->order);
  81                         if (nest == NULL)
  82                                 goto nla_put_failure;
  83                         if (type == RTM_DELACTION)
  84                                 err = tcf_action_dump_1(skb, a, 0, 1);
  85                         else
  86                                 err = tcf_action_dump_1(skb, a, 0, 0);
  87                         if (err < 0) {
  88                                 index--;
  89                                 nla_nest_cancel(skb, nest);
  90                                 goto done;
  91                         }
  92                         nla_nest_end(skb, nest);
  93                         n_i++;
  94                 }
  95         }
  96 done:
  97         spin_unlock_bh(&hinfo->lock);
  98         if (n_i)
  99                 cb->args[0] += n_i;
 100         return n_i;
 101
 102 nla_put_failure:
 103         nla_nest_cancel(skb, nest);
 104         goto done;
 105 }
 106
 107 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
 108         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
 109         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
 110         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
 111         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
 112 };
 113
 114 static int tcf_act_police_locate(struct net *net, struct nlattr *nla,
 115                                  struct nlattr *est, struct tc_action *a,
 116                                  int ovr, int bind)
 117 {
 118         unsigned int h;
 119         int ret = 0, err;
 120         struct nlattr *tb[TCA_POLICE_MAX + 1];
 121         struct tc_police *parm;
 122         struct tcf_police *police;
 123         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
 124         struct tcf_hashinfo *hinfo = a->ops->hinfo;
 125         int size;
 126
 127         if (nla == NULL)
 128                 return -EINVAL;
 129
 130         err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy);
 131         if (err < 0)
 132                 return err;
 133
 134         if (tb[TCA_POLICE_TBF] == NULL)
 135                 return -EINVAL;
 136         size = nla_len(tb[TCA_POLICE_TBF]);
 137         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
 138                 return -EINVAL;
 139         parm = nla_data(tb[TCA_POLICE_TBF]);
 140
 141         if (parm->index) {
 142                 if (tcf_hash_search(a, parm->index)) {
 143                         police = to_police(a->priv);
 144                         if (bind) {
 145                                 police->tcf_bindcnt += 1;
 146                                 police->tcf_refcnt += 1;
 147                                 return 0;
 148                         }
 149                         if (ovr)
 150                                 goto override;
 151                         /* not replacing */
 152                         return -EEXIST;
 153                 }
 154         }
 155
 156         police = kzalloc(sizeof(*police), GFP_KERNEL);
 157         if (police == NULL)
 158                 return -ENOMEM;
 159         ret = ACT_P_CREATED;
 160         police->tcf_refcnt = 1;
 161         spin_lock_init(&police->tcf_lock);
 162         if (bind)
 163                 police->tcf_bindcnt = 1;
 164 override:
 165         if (parm->rate.rate) {
 166                 err = -ENOMEM;
 167                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
 168                 if (R_tab == NULL)
 169                         goto failure;
 170
 171                 if (parm->peakrate.rate) {
 172                         P_tab = qdisc_get_rtab(&parm->peakrate,
 173                                                tb[TCA_POLICE_PEAKRATE]);
 174                         if (P_tab == NULL)
 175                                 goto failure;
 176                 }
 177         }
 178
 179         spin_lock_bh(&police->tcf_lock);
 180         if (est) {
 181                 err = gen_replace_estimator(&police->tcf_bstats, NULL,
 182                                             &police->tcf_rate_est,
 183                                             &police->tcf_lock, est);
 184                 if (err)
 185                         goto failure_unlock;
 186         } else if (tb[TCA_POLICE_AVRATE] &&
 187                    (ret == ACT_P_CREATED ||
 188                     !gen_estimator_active(&police->tcf_bstats,
 189                                           &police->tcf_rate_est))) {
 190                 err = -EINVAL;
 191                 goto failure_unlock;
 192         }
 193
 194         /* No failure allowed after this point */
 195         police->tcfp_mtu = parm->mtu;
 196         if (police->tcfp_mtu == 0) {
 197                 police->tcfp_mtu = ~0;
 198                 if (R_tab)
 199                         police->tcfp_mtu = 255 << R_tab->rate.cell_log;
 200         }
 201         if (R_tab) {
 202                 police->rate_present = true;
 203                 psched_ratecfg_precompute(&police->rate, &R_tab->rate, 0);
 204                 qdisc_put_rtab(R_tab);
 205         } else {
 206                 police->rate_present = false;
 207         }
 208         if (P_tab) {
 209                 police->peak_present = true;
 210                 psched_ratecfg_precompute(&police->peak, &P_tab->rate, 0);
 211                 qdisc_put_rtab(P_tab);
 212         } else {
 213                 police->peak_present = false;
 214         }
 215
 216         if (tb[TCA_POLICE_RESULT])
 217                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 218         police->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
 219         police->tcfp_toks = police->tcfp_burst;
 220         if (police->peak_present) {
 221                 police->tcfp_mtu_ptoks = (s64) psched_l2t_ns(&police->peak,
 222                                                              police->tcfp_mtu);
 223                 police->tcfp_ptoks = police->tcfp_mtu_ptoks;
 224         }
 225         police->tcf_action = parm->action;
 226
 227         if (tb[TCA_POLICE_AVRATE])
 228                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 229
 230         spin_unlock_bh(&police->tcf_lock);
 231         if (ret != ACT_P_CREATED)
 232                 return ret;
 233
 234         police->tcfp_t_c = ktime_get_ns();
 235         police->tcf_index = parm->index ? parm->index :
 236                 tcf_hash_new_index(hinfo);
 237         h = tcf_hash(police->tcf_index, POL_TAB_MASK);
 238         spin_lock_bh(&hinfo->lock);
 239         hlist_add_head(&police->tcf_head, &hinfo->htab[h]);
 240         spin_unlock_bh(&hinfo->lock);
 241
 242         a->priv = police;
 243         return ret;
 244
 245 failure_unlock:
 246         spin_unlock_bh(&police->tcf_lock);
 247 failure:
 248         qdisc_put_rtab(P_tab);
 249         qdisc_put_rtab(R_tab);
 250         if (ret == ACT_P_CREATED)
 251                 kfree(police);
 252         return err;
 253 }
 254
 255 static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a,
 256                           struct tcf_result *res)
 257 {
 258         struct tcf_police *police = a->priv;
 259         s64 now;
 260         s64 toks;
 261         s64 ptoks = 0;
 262
 263         spin_lock(&police->tcf_lock);
 264
 265         bstats_update(&police->tcf_bstats, skb);
 266
 267         if (police->tcfp_ewma_rate &&
 268             police->tcf_rate_est.bps >= police->tcfp_ewma_rate) {
 269                 police->tcf_qstats.overlimits++;
 270                 if (police->tcf_action == TC_ACT_SHOT)
 271                         police->tcf_qstats.drops++;
 272                 spin_unlock(&police->tcf_lock);
 273                 return police->tcf_action;
 274         }
 275
 276         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 277                 if (!police->rate_present) {
 278                         spin_unlock(&police->tcf_lock);
 279                         return police->tcfp_result;
 280                 }
 281
 282                 now = ktime_get_ns();
 283                 toks = min_t(s64, now - police->tcfp_t_c,
 284                              police->tcfp_burst);
 285                 if (police->peak_present) {
 286                         ptoks = toks + police->tcfp_ptoks;
 287                         if (ptoks > police->tcfp_mtu_ptoks)
 288                                 ptoks = police->tcfp_mtu_ptoks;
 289                         ptoks -= (s64) psched_l2t_ns(&police->peak,
 290                                                      qdisc_pkt_len(skb));
 291                 }
 292                 toks += police->tcfp_toks;
 293                 if (toks > police->tcfp_burst)
 294                         toks = police->tcfp_burst;
 295                 toks -= (s64) psched_l2t_ns(&police->rate, qdisc_pkt_len(skb));
 296                 if ((toks|ptoks) >= 0) {
 297                         police->tcfp_t_c = now;
 298                         police->tcfp_toks = toks;
 299                         police->tcfp_ptoks = ptoks;
 300                         spin_unlock(&police->tcf_lock);
 301                         return police->tcfp_result;
 302                 }
 303         }
 304
 305         police->tcf_qstats.overlimits++;
 306         if (police->tcf_action == TC_ACT_SHOT)
 307                 police->tcf_qstats.drops++;
 308         spin_unlock(&police->tcf_lock);
 309         return police->tcf_action;
 310 }
 311
 312 static int
 313 tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 314 {
 315         unsigned char *b = skb_tail_pointer(skb);
 316         struct tcf_police *police = a->priv;
 317         struct tc_police opt = {
 318                 .index = police->tcf_index,
 319                 .action = police->tcf_action,
 320                 .mtu = police->tcfp_mtu,
 321                 .burst = PSCHED_NS2TICKS(police->tcfp_burst),
 322                 .refcnt = police->tcf_refcnt - ref,
 323                 .bindcnt = police->tcf_bindcnt - bind,
 324         };
 325
 326         if (police->rate_present)
 327                 psched_ratecfg_getrate(&opt.rate, &police->rate);
 328         if (police->peak_present)
 329                 psched_ratecfg_getrate(&opt.peakrate, &police->peak);
 330         if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
 331                 goto nla_put_failure;
 332         if (police->tcfp_result &&
 333             nla_put_u32(skb, TCA_POLICE_RESULT, police->tcfp_result))
 334                 goto nla_put_failure;
 335         if (police->tcfp_ewma_rate &&
 336             nla_put_u32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate))
 337                 goto nla_put_failure;
 338         return skb->len;
 339
 340 nla_put_failure:
 341         nlmsg_trim(skb, b);
 342         return -1;
 343 }
 344
 345 MODULE_AUTHOR("Alexey Kuznetsov");
 346 MODULE_DESCRIPTION("Policing actions");
 347 MODULE_LICENSE("GPL");
 348
 349 static struct tc_action_ops act_police_ops = {
 350         .kind           =       "police",
 351         .type           =       TCA_ID_POLICE,
 352         .owner          =       THIS_MODULE,
 353         .act            =       tcf_act_police,
 354         .dump           =       tcf_act_police_dump,
 355         .init           =       tcf_act_police_locate,
 356         .walk           =       tcf_act_police_walker
 357 };
 358
 359 static int __init
 360 police_init_module(void)
 361 {
 362         return tcf_register_action(&act_police_ops, POL_TAB_MASK);
 363 }
 364
 365 static void __exit
 366 police_cleanup_module(void)
 367 {
 368         tcf_unregister_action(&act_police_ops);
 369 }
 370
 371 module_init(police_init_module);
 372 module_exit(police_cleanup_module);