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   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 <net/act_api.h>
  22 #include <net/netlink.h>
  23
  24 #define L2T(p,L)   qdisc_l2t((p)->tcfp_R_tab, L)
  25 #define L2T_P(p,L) qdisc_l2t((p)->tcfp_P_tab, L)
  26
  27 #define POL_TAB_MASK     15
  28 static struct tcf_common *tcf_police_ht[POL_TAB_MASK + 1];
  29 static u32 police_idx_gen;
  30 static DEFINE_RWLOCK(police_lock);
  31
  32 static struct tcf_hashinfo police_hash_info = {
  33         .htab   =       tcf_police_ht,
  34         .hmask  =       POL_TAB_MASK,
  35         .lock   =       &police_lock,
  36 };
  37
  38 /* old policer structure from before tc actions */
  39 struct tc_police_compat
  40 {
  41         u32                     index;
  42         int                     action;
  43         u32                     limit;
  44         u32                     burst;
  45         u32                     mtu;
  46         struct tc_ratespec      rate;
  47         struct tc_ratespec      peakrate;
  48 };
  49
  50 /* Each policer is serialized by its individual spinlock */
  51
  52 static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb,
  53                               int type, struct tc_action *a)
  54 {
  55         struct tcf_common *p;
  56         int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
  57         struct nlattr *nest;
  58
  59         read_lock_bh(&police_lock);
  60
  61         s_i = cb->args[0];
  62
  63         for (i = 0; i < (POL_TAB_MASK + 1); i++) {
  64                 p = tcf_police_ht[tcf_hash(i, POL_TAB_MASK)];
  65
  66                 for (; p; p = p->tcfc_next) {
  67                         index++;
  68                         if (index < s_i)
  69                                 continue;
  70                         a->priv = p;
  71                         a->order = index;
  72                         nest = nla_nest_start(skb, a->order);
  73                         if (nest == NULL)
  74                                 goto nla_put_failure;
  75                         if (type == RTM_DELACTION)
  76                                 err = tcf_action_dump_1(skb, a, 0, 1);
  77                         else
  78                                 err = tcf_action_dump_1(skb, a, 0, 0);
  79                         if (err < 0) {
  80                                 index--;
  81                                 nla_nest_cancel(skb, nest);
  82                                 goto done;
  83                         }
  84                         nla_nest_end(skb, nest);
  85                         n_i++;
  86                 }
  87         }
  88 done:
  89         read_unlock_bh(&police_lock);
  90         if (n_i)
  91                 cb->args[0] += n_i;
  92         return n_i;
  93
  94 nla_put_failure:
  95         nla_nest_cancel(skb, nest);
  96         goto done;
  97 }
  98
  99 static void tcf_police_destroy(struct tcf_police *p)
 100 {
 101         unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK);
 102         struct tcf_common **p1p;
 103
 104         for (p1p = &tcf_police_ht[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
 105                 if (*p1p == &p->common) {
 106                         write_lock_bh(&police_lock);
 107                         *p1p = p->tcf_next;
 108                         write_unlock_bh(&police_lock);
 109                         gen_kill_estimator(&p->tcf_bstats,
 110                                            &p->tcf_rate_est);
 111                         if (p->tcfp_R_tab)
 112                                 qdisc_put_rtab(p->tcfp_R_tab);
 113                         if (p->tcfp_P_tab)
 114                                 qdisc_put_rtab(p->tcfp_P_tab);
 115                         kfree(p);
 116                         return;
 117                 }
 118         }
 119         WARN_ON(1);
 120 }
 121
 122 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
 123         [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
 124         [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
 125         [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
 126         [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
 127 };
 128
 129 static int tcf_act_police_locate(struct nlattr *nla, struct nlattr *est,
 130                                  struct tc_action *a, int ovr, int bind)
 131 {
 132         unsigned h;
 133         int ret = 0, err;
 134         struct nlattr *tb[TCA_POLICE_MAX + 1];
 135         struct tc_police *parm;
 136         struct tcf_police *police;
 137         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
 138         int size;
 139
 140         if (nla == NULL)
 141                 return -EINVAL;
 142
 143         err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy);
 144         if (err < 0)
 145                 return err;
 146
 147         if (tb[TCA_POLICE_TBF] == NULL)
 148                 return -EINVAL;
 149         size = nla_len(tb[TCA_POLICE_TBF]);
 150         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
 151                 return -EINVAL;
 152         parm = nla_data(tb[TCA_POLICE_TBF]);
 153
 154         if (parm->index) {
 155                 struct tcf_common *pc;
 156
 157                 pc = tcf_hash_lookup(parm->index, &police_hash_info);
 158                 if (pc != NULL) {
 159                         a->priv = pc;
 160                         police = to_police(pc);
 161                         if (bind) {
 162                                 police->tcf_bindcnt += 1;
 163                                 police->tcf_refcnt += 1;
 164                         }
 165                         if (ovr)
 166                                 goto override;
 167                         return ret;
 168                 }
 169         }
 170
 171         police = kzalloc(sizeof(*police), GFP_KERNEL);
 172         if (police == NULL)
 173                 return -ENOMEM;
 174         ret = ACT_P_CREATED;
 175         police->tcf_refcnt = 1;
 176         spin_lock_init(&police->tcf_lock);
 177         if (bind)
 178                 police->tcf_bindcnt = 1;
 179 override:
 180         if (parm->rate.rate) {
 181                 err = -ENOMEM;
 182                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]);
 183                 if (R_tab == NULL)
 184                         goto failure;
 185
 186                 if (parm->peakrate.rate) {
 187                         P_tab = qdisc_get_rtab(&parm->peakrate,
 188                                                tb[TCA_POLICE_PEAKRATE]);
 189                         if (P_tab == NULL)
 190                                 goto failure;
 191                 }
 192         }
 193
 194         spin_lock_bh(&police->tcf_lock);
 195         if (est) {
 196                 err = gen_replace_estimator(&police->tcf_bstats,
 197                                             &police->tcf_rate_est,
 198                                             &police->tcf_lock, est);
 199                 if (err)
 200                         goto failure_unlock;
 201         } else if (tb[TCA_POLICE_AVRATE] &&
 202                    (ret == ACT_P_CREATED ||
 203                     !gen_estimator_active(&police->tcf_bstats,
 204                                           &police->tcf_rate_est))) {
 205                 err = -EINVAL;
 206                 goto failure_unlock;
 207         }
 208
 209         /* No failure allowed after this point */
 210         if (R_tab != NULL) {
 211                 qdisc_put_rtab(police->tcfp_R_tab);
 212                 police->tcfp_R_tab = R_tab;
 213         }
 214         if (P_tab != NULL) {
 215                 qdisc_put_rtab(police->tcfp_P_tab);
 216                 police->tcfp_P_tab = P_tab;
 217         }
 218
 219         if (tb[TCA_POLICE_RESULT])
 220                 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
 221         police->tcfp_toks = police->tcfp_burst = parm->burst;
 222         police->tcfp_mtu = parm->mtu;
 223         if (police->tcfp_mtu == 0) {
 224                 police->tcfp_mtu = ~0;
 225                 if (police->tcfp_R_tab)
 226                         police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log;
 227         }
 228         if (police->tcfp_P_tab)
 229                 police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu);
 230         police->tcf_action = parm->action;
 231
 232         if (tb[TCA_POLICE_AVRATE])
 233                 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 234
 235         spin_unlock_bh(&police->tcf_lock);
 236         if (ret != ACT_P_CREATED)
 237                 return ret;
 238
 239         police->tcfp_t_c = psched_get_time();
 240         police->tcf_index = parm->index ? parm->index :
 241                 tcf_hash_new_index(&police_idx_gen, &police_hash_info);
 242         h = tcf_hash(police->tcf_index, POL_TAB_MASK);
 243         write_lock_bh(&police_lock);
 244         police->tcf_next = tcf_police_ht[h];
 245         tcf_police_ht[h] = &police->common;
 246         write_unlock_bh(&police_lock);
 247
 248         a->priv = police;
 249         return ret;
 250
 251 failure_unlock:
 252         spin_unlock_bh(&police->tcf_lock);
 253 failure:
 254         if (P_tab)
 255                 qdisc_put_rtab(P_tab);
 256         if (R_tab)
 257                 qdisc_put_rtab(R_tab);
 258         if (ret == ACT_P_CREATED)
 259                 kfree(police);
 260         return err;
 261 }
 262
 263 static int tcf_act_police_cleanup(struct tc_action *a, int bind)
 264 {
 265         struct tcf_police *p = a->priv;
 266         int ret = 0;
 267
 268         if (p != NULL) {
 269                 if (bind)
 270                         p->tcf_bindcnt--;
 271
 272                 p->tcf_refcnt--;
 273                 if (p->tcf_refcnt <= 0 && !p->tcf_bindcnt) {
 274                         tcf_police_destroy(p);
 275                         ret = 1;
 276                 }
 277         }
 278         return ret;
 279 }
 280
 281 static int tcf_act_police(struct sk_buff *skb, struct tc_action *a,
 282                           struct tcf_result *res)
 283 {
 284         struct tcf_police *police = a->priv;
 285         psched_time_t now;
 286         long toks;
 287         long ptoks = 0;
 288
 289         spin_lock(&police->tcf_lock);
 290
 291         police->tcf_bstats.bytes += qdisc_pkt_len(skb);
 292         police->tcf_bstats.packets++;
 293
 294         if (police->tcfp_ewma_rate &&
 295             police->tcf_rate_est.bps >= police->tcfp_ewma_rate) {
 296                 police->tcf_qstats.overlimits++;
 297                 if (police->tcf_action == TC_ACT_SHOT)
 298                         police->tcf_qstats.drops++;
 299                 spin_unlock(&police->tcf_lock);
 300                 return police->tcf_action;
 301         }
 302
 303         if (qdisc_pkt_len(skb) <= police->tcfp_mtu) {
 304                 if (police->tcfp_R_tab == NULL) {
 305                         spin_unlock(&police->tcf_lock);
 306                         return police->tcfp_result;
 307                 }
 308
 309                 now = psched_get_time();
 310                 toks = psched_tdiff_bounded(now, police->tcfp_t_c,
 311                                             police->tcfp_burst);
 312                 if (police->tcfp_P_tab) {
 313                         ptoks = toks + police->tcfp_ptoks;
 314                         if (ptoks > (long)L2T_P(police, police->tcfp_mtu))
 315                                 ptoks = (long)L2T_P(police, police->tcfp_mtu);
 316                         ptoks -= L2T_P(police, qdisc_pkt_len(skb));
 317                 }
 318                 toks += police->tcfp_toks;
 319                 if (toks > (long)police->tcfp_burst)
 320                         toks = police->tcfp_burst;
 321                 toks -= L2T(police, qdisc_pkt_len(skb));
 322                 if ((toks|ptoks) >= 0) {
 323                         police->tcfp_t_c = now;
 324                         police->tcfp_toks = toks;
 325                         police->tcfp_ptoks = ptoks;
 326                         spin_unlock(&police->tcf_lock);
 327                         return police->tcfp_result;
 328                 }
 329         }
 330
 331         police->tcf_qstats.overlimits++;
 332         if (police->tcf_action == TC_ACT_SHOT)
 333                 police->tcf_qstats.drops++;
 334         spin_unlock(&police->tcf_lock);
 335         return police->tcf_action;
 336 }
 337
 338 static int
 339 tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 340 {
 341         unsigned char *b = skb_tail_pointer(skb);
 342         struct tcf_police *police = a->priv;
 343         struct tc_police opt;
 344
 345         opt.index = police->tcf_index;
 346         opt.action = police->tcf_action;
 347         opt.mtu = police->tcfp_mtu;
 348         opt.burst = police->tcfp_burst;
 349         opt.refcnt = police->tcf_refcnt - ref;
 350         opt.bindcnt = police->tcf_bindcnt - bind;
 351         if (police->tcfp_R_tab)
 352                 opt.rate = police->tcfp_R_tab->rate;
 353         else
 354                 memset(&opt.rate, 0, sizeof(opt.rate));
 355         if (police->tcfp_P_tab)
 356                 opt.peakrate = police->tcfp_P_tab->rate;
 357         else
 358                 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
 359         NLA_PUT(skb, TCA_POLICE_TBF, sizeof(opt), &opt);
 360         if (police->tcfp_result)
 361                 NLA_PUT_U32(skb, TCA_POLICE_RESULT, police->tcfp_result);
 362         if (police->tcfp_ewma_rate)
 363                 NLA_PUT_U32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate);
 364         return skb->len;
 365
 366 nla_put_failure:
 367         nlmsg_trim(skb, b);
 368         return -1;
 369 }
 370
 371 MODULE_AUTHOR("Alexey Kuznetsov");
 372 MODULE_DESCRIPTION("Policing actions");
 373 MODULE_LICENSE("GPL");
 374
 375 static struct tc_action_ops act_police_ops = {
 376         .kind           =       "police",
 377         .hinfo          =       &police_hash_info,
 378         .type           =       TCA_ID_POLICE,
 379         .capab          =       TCA_CAP_NONE,
 380         .owner          =       THIS_MODULE,
 381         .act            =       tcf_act_police,
 382         .dump           =       tcf_act_police_dump,
 383         .cleanup        =       tcf_act_police_cleanup,
 384         .lookup         =       tcf_hash_search,
 385         .init           =       tcf_act_police_locate,
 386         .walk           =       tcf_act_police_walker
 387 };
 388
 389 static int __init
 390 police_init_module(void)
 391 {
 392         return tcf_register_action(&act_police_ops);
 393 }
 394
 395 static void __exit
 396 police_cleanup_module(void)
 397 {
 398         tcf_unregister_action(&act_police_ops);
 399 }
 400
 401 module_init(police_init_module);
 402 module_exit(police_cleanup_module);