net/sched/act_police.c

   1 /*
   2  * net/sched/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 #define L2T(p,L)   qdisc_l2t((p)->tcfp_R_tab, L)
  26 #define L2T_P(p,L) qdisc_l2t((p)->tcfp_P_tab, L)
  27
  28 #define POL_TAB_MASK     15
  29 static struct tcf_common *tcf_police_ht[POL_TAB_MASK + 1];
  30 static u32 police_idx_gen;
  31 static DEFINE_RWLOCK(police_lock);
  32
  33 static struct tcf_hashinfo police_hash_info = {
  34         .htab   =       tcf_police_ht,
  35         .hmask  =       POL_TAB_MASK,
  36         .lock   =       &police_lock,
  37 };
  38
  39 /* old policer structure from before tc actions */
  40 struct tc_police_compat
  41 {
  42         u32                     index;
  43         int                     action;
  44         u32                     limit;
  45         u32                     burst;
  46         u32                     mtu;
  47         struct tc_ratespec      rate;
  48         struct tc_ratespec      peakrate;
  49 };
  50
  51 /* Each policer is serialized by its individual spinlock */
  52
  53 static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb,
  54                               int type, struct tc_action *a)
  55 {
  56         struct tcf_common *p;
  57         int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
  58         struct nlattr *nest;
  59
  60         read_lock_bh(&police_lock);
  61
  62         s_i = cb->args[0];
  63
  64         for (i = 0; i < (POL_TAB_MASK + 1); i++) {
  65                 p = tcf_police_ht[tcf_hash(i, POL_TAB_MASK)];
  66
  67                 for (; p; p = p->tcfc_next) {
  68                         index++;
  69                         if (index < s_i)
  70                                 continue;
  71                         a->priv = p;
  72                         a->order = index;
  73                         nest = nla_nest_start(skb, a->order);
  74                         if (nest == NULL)
  75                                 goto nla_put_failure;
  76                         if (type == RTM_DELACTION)
  77                                 err = tcf_action_dump_1(skb, a, 0, 1);
  78                         else
  79                                 err = tcf_action_dump_1(skb, a, 0, 0);
  80                         if (err < 0) {
  81                                 index--;
  82                                 nla_nest_cancel(skb, nest);
  83                                 goto done;
  84                         }
  85                         nla_nest_end(skb, nest);
  86                         n_i++;
  87                 }
  88         }
  89 done:
  90         read_unlock_bh(&police_lock);
  91         if (n_i)
  92                 cb->args[0] += n_i;
  93         return n_i;
  94
  95 nla_put_failure:
  96         nla_nest_cancel(skb, nest);
  97         goto done;
  98 }
  99
 100 static void tcf_police_free_rcu(struct rcu_head *head)
 101 {
 102         kfree(container_of(head, struct tcf_police, tcf_rcu));
 103 }
 104
 105 static void tcf_police_destroy(struct tcf_police *p)
 106 {
 107         unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK);
 108         struct tcf_common **p1p;
 109
 110         for (p1p = &tcf_police_ht[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
 111                 if (*p1p == &p->common) {
 112                         write_lock_bh(&police_lock);
 113                         *p1p = p->tcf_next;
 114                         write_unlock_bh(&police_lock);
 115                         gen_kill_estimator(&p->tcf_bstats,
 116                                            &p->tcf_rate_est);
 117                         if (p->tcfp_R_tab)
 118                                 qdisc_put_rtab(p->tcfp_R_tab);
 119                         if (p->tcfp_P_tab)
 120                                 qdisc_put_rtab(p->tcfp_P_tab);
 121                         /*
 122                          * gen_estimator est_timer() might access p->tcf_lock
 123                          * or bstats, wait a RCU grace period before freeing p
 124                          */
 125                         call_rcu(&p->tcf_rcu, tcf_police_free_rcu);
 126                         return;
 127                 }
 128         }
 129         WARN_ON(1);
 130 }
 131
 132 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
 133         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
 134         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
 135         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
 136         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
 137 };
 138
 139 static int tcf_act_police_locate(struct nlattr *nla, struct nlattr *est,
 140                                  struct tc_action *a, int ovr, int bind)
 141 {
 142         unsigned h;
 143         int ret = 0, err;
 144         struct nlattr *tb[TCA_POLICE_MAX + 1];
 145         struct tc_police *parm;
 146         struct tcf_police *police;
 147         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
 148         int size;
 149
 150         if (nla == NULL)
 151                 return -EINVAL;
 152
 153         err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy);
 154         if (err < 0)
 155                 return err;
 156
 157         if (tb[TCA_POLICE_TBF] == NULL)
 158                 return -EINVAL;
 159         size = nla_len(tb[TCA_POLICE_TBF]);
 160         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
 161                 return -EINVAL;
 162         parm = nla_data(tb[TCA_POLICE_TBF]);
 163
 164         if (parm->index) {
 165                 struct tcf_common *pc;
 166
 167                 pc = tcf_hash_lookup(parm->index, &police_hash_info);
 168                 if (pc != NULL) {
 169                         a->priv = pc;
 170                         police = to_police(pc);
 171                         if (bind) {
 172                                 police->tcf_bindcnt += 1;
 173                                 police->tcf_refcnt += 1;
 174                         }
 175                         if (ovr)
 176                                 goto override;
 177                         return ret;
 178                 }
 179         }
 180
 181         police = kzalloc(sizeof(*police), GFP_KERNEL);
 182         if (police == NULL)
 183                 return -ENOMEM;
 184         ret = ACT_P_CREATED;
 185         police->tcf_refcnt = 1;
 186         spin_lock_init(&police->tcf_lock);
 187         if (bind)
 188                 police->tcf_bindcnt = 1;
 189 override:
 190         if (parm->rate.rate) {
 191                 err = -ENOMEM;
 192                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
 193                 if (R_tab == NULL)
 194                         goto failure;
 195
 196                 if (parm->peakrate.rate) {
 197                         P_tab = qdisc_get_rtab(&parm->peakrate,
 198                                                tb[TCA_POLICE_PEAKRATE]);
 199                         if (P_tab == NULL)
 200                                 goto failure;
 201                 }
 202         }
 203
 204         spin_lock_bh(&police->tcf_lock);
 205         if (est) {
 206                 err = gen_replace_estimator(&police->tcf_bstats,
 207                                             &police->tcf_rate_est,
 208                                             &police->tcf_lock, est);
 209                 if (err)
 210                         goto failure_unlock;
 211         } else if (tb[TCA_POLICE_AVRATE] &&
 212                    (ret == ACT_P_CREATED ||
 213                     !gen_estimator_active(&police->tcf_bstats,
 214                                           &police->tcf_rate_est))) {
 215                 err = -EINVAL;
 216                 goto failure_unlock;
 217         }
 218
 219         /* No failure allowed after this point */
 220         if (R_tab != NULL) {
 221                 qdisc_put_rtab(police->tcfp_R_tab);
 222                 police->tcfp_R_tab = R_tab;
 223         }
 224         if (P_tab != NULL) {
 225                 qdisc_put_rtab(police->tcfp_P_tab);
 226                 police->tcfp_P_tab = P_tab;
 227         }
 228
 229         if (tb[TCA_POLICE_RESULT])
 230                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 231         police->tcfp_toks = police->tcfp_burst = parm->burst;
 232         police->tcfp_mtu = parm->mtu;
 233         if (police->tcfp_mtu == 0) {
 234                 police->tcfp_mtu = ~0;
 235                 if (police->tcfp_R_tab)
 236                         police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log;
 237         }
 238         if (police->tcfp_P_tab)
 239                 police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu);
 240         police->tcf_action = parm->action;
 241
 242         if (tb[TCA_POLICE_AVRATE])
 243                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 244
 245         spin_unlock_bh(&police->tcf_lock);
 246         if (ret != ACT_P_CREATED)
 247                 return ret;
 248
 249         police->tcfp_t_c = psched_get_time();
 250         police->tcf_index = parm->index ? parm->index :
 251                 tcf_hash_new_index(&police_idx_gen, &police_hash_info);
 252         h = tcf_hash(police->tcf_index, POL_TAB_MASK);
 253         write_lock_bh(&police_lock);
 254         police->tcf_next = tcf_police_ht[h];
 255         tcf_police_ht[h] = &police->common;
 256         write_unlock_bh(&police_lock);
 257
 258         a->priv = police;
 259         return ret;
 260
 261 failure_unlock:
 262         spin_unlock_bh(&police->tcf_lock);
 263 failure:
 264         if (P_tab)
 265                 qdisc_put_rtab(P_tab);
 266         if (R_tab)
 267                 qdisc_put_rtab(R_tab);
 268         if (ret == ACT_P_CREATED)
 269                 kfree(police);
 270         return err;
 271 }
 272
 273 static int tcf_act_police_cleanup(struct tc_action *a, int bind)
 274 {
 275         struct tcf_police *p = a->priv;
 276         int ret = 0;
 277
 278         if (p != NULL) {
 279                 if (bind)
 280                         p->tcf_bindcnt--;
 281
 282                 p->tcf_refcnt--;
 283                 if (p->tcf_refcnt <= 0 && !p->tcf_bindcnt) {
 284                         tcf_police_destroy(p);
 285                         ret = 1;
 286                 }
 287         }
 288         return ret;
 289 }
 290
 291 static int tcf_act_police(struct sk_buff *skb, struct tc_action *a,
 292                           struct tcf_result *res)
 293 {
 294         struct tcf_police *police = a->priv;
 295         psched_time_t now;
 296         long toks;
 297         long ptoks = 0;
 298
 299         spin_lock(&police->tcf_lock);
 300
 301         police->tcf_bstats.bytes += qdisc_pkt_len(skb);
 302         police->tcf_bstats.packets++;
 303
 304         if (police->tcfp_ewma_rate &&
 305             police->tcf_rate_est.bps >= police->tcfp_ewma_rate) {
 306                 police->tcf_qstats.overlimits++;
 307                 if (police->tcf_action == TC_ACT_SHOT)
 308                         police->tcf_qstats.drops++;
 309                 spin_unlock(&police->tcf_lock);
 310                 return police->tcf_action;
 311         }
 312
 313         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 314                 if (police->tcfp_R_tab == NULL) {
 315                         spin_unlock(&police->tcf_lock);
 316                         return police->tcfp_result;
 317                 }
 318
 319                 now = psched_get_time();
 320                 toks = psched_tdiff_bounded(now, police->tcfp_t_c,
 321                                             police->tcfp_burst);
 322                 if (police->tcfp_P_tab) {
 323                         ptoks = toks + police->tcfp_ptoks;
 324                         if (ptoks > (long)L2T_P(police, police->tcfp_mtu))
 325                                 ptoks = (long)L2T_P(police, police->tcfp_mtu);
 326                         ptoks -= L2T_P(police, qdisc_pkt_len(skb));
 327                 }
 328                 toks += police->tcfp_toks;
 329                 if (toks > (long)police->tcfp_burst)
 330                         toks = police->tcfp_burst;
 331                 toks -= L2T(police, qdisc_pkt_len(skb));
 332                 if ((toks|ptoks) >= 0) {
 333                         police->tcfp_t_c = now;
 334                         police->tcfp_toks = toks;
 335                         police->tcfp_ptoks = ptoks;
 336                         spin_unlock(&police->tcf_lock);
 337                         return police->tcfp_result;
 338                 }
 339         }
 340
 341         police->tcf_qstats.overlimits++;
 342         if (police->tcf_action == TC_ACT_SHOT)
 343                 police->tcf_qstats.drops++;
 344         spin_unlock(&police->tcf_lock);
 345         return police->tcf_action;
 346 }
 347
 348 static int
 349 tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 350 {
 351         unsigned char *b = skb_tail_pointer(skb);
 352         struct tcf_police *police = a->priv;
 353         struct tc_police opt = {
 354                 .index = police->tcf_index,
 355                 .action = police->tcf_action,
 356                 .mtu = police->tcfp_mtu,
 357                 .burst = police->tcfp_burst,
 358                 .refcnt = police->tcf_refcnt - ref,
 359                 .bindcnt = police->tcf_bindcnt - bind,
 360         };
 361
 362         if (police->tcfp_R_tab)
 363                 opt.rate = police->tcfp_R_tab->rate;
 364         if (police->tcfp_P_tab)
 365                 opt.peakrate = police->tcfp_P_tab->rate;
 366         NLA_PUT(skb, TCA_POLICE_TBF, sizeof(opt), &opt);
 367         if (police->tcfp_result)
 368                 NLA_PUT_U32(skb, TCA_POLICE_RESULT, police->tcfp_result);
 369         if (police->tcfp_ewma_rate)
 370                 NLA_PUT_U32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate);
 371         return skb->len;
 372
 373 nla_put_failure:
 374         nlmsg_trim(skb, b);
 375         return -1;
 376 }
 377
 378 MODULE_AUTHOR("Alexey Kuznetsov");
 379 MODULE_DESCRIPTION("Policing actions");
 380 MODULE_LICENSE("GPL");
 381
 382 static struct tc_action_ops act_police_ops = {
 383         .kind           =       "police",
 384         .hinfo          =       &police_hash_info,
 385         .type           =       TCA_ID_POLICE,
 386         .capab          =       TCA_CAP_NONE,
 387         .owner          =       THIS_MODULE,
 388         .act            =       tcf_act_police,
 389         .dump           =       tcf_act_police_dump,
 390         .cleanup        =       tcf_act_police_cleanup,
 391         .lookup         =       tcf_hash_search,
 392         .init           =       tcf_act_police_locate,
 393         .walk           =       tcf_act_police_walker
 394 };
 395
 396 static int __init
 397 police_init_module(void)
 398 {
 399         return tcf_register_action(&act_police_ops);
 400 }
 401
 402 static void __exit
 403 police_cleanup_module(void)
 404 {
 405         tcf_unregister_action(&act_police_ops);
 406         rcu_barrier(); /* Wait for completion of call_rcu()'s (tcf_police_free_rcu) */
 407 }
 408
 409 module_init(police_init_module);
 410 module_exit(police_cleanup_module);