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 <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 rtattr *r;
  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                         r = (struct rtattr *)skb_tail_pointer(skb);
  73                         RTA_PUT(skb, a->order, 0, NULL);
  74                         if (type == RTM_DELACTION)
  75                                 err = tcf_action_dump_1(skb, a, 0, 1);
  76                         else
  77                                 err = tcf_action_dump_1(skb, a, 0, 0);
  78                         if (err < 0) {
  79                                 index--;
  80                                 nlmsg_trim(skb, r);
  81                                 goto done;
  82                         }
  83                         r->rta_len = skb_tail_pointer(skb) - (u8 *)r;
  84                         n_i++;
  85                 }
  86         }
  87 done:
  88         read_unlock_bh(&police_lock);
  89         if (n_i)
  90                 cb->args[0] += n_i;
  91         return n_i;
  92
  93 rtattr_failure:
  94         nlmsg_trim(skb, r);
  95         goto done;
  96 }
  97
  98 static void tcf_police_destroy(struct tcf_police *p)
  99 {
 100         unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK);
 101         struct tcf_common **p1p;
 102
 103         for (p1p = &tcf_police_ht[h]; *p1p; p1p = &(*p1p)->tcfc_next) {
 104                 if (*p1p == &p->common) {
 105                         write_lock_bh(&police_lock);
 106                         *p1p = p->tcf_next;
 107                         write_unlock_bh(&police_lock);
 108                         gen_kill_estimator(&p->tcf_bstats,
 109                                            &p->tcf_rate_est);
 110                         if (p->tcfp_R_tab)
 111                                 qdisc_put_rtab(p->tcfp_R_tab);
 112                         if (p->tcfp_P_tab)
 113                                 qdisc_put_rtab(p->tcfp_P_tab);
 114                         kfree(p);
 115                         return;
 116                 }
 117         }
 118         BUG_TRAP(0);
 119 }
 120
 121 static int tcf_act_police_locate(struct rtattr *rta, struct rtattr *est,
 122                                  struct tc_action *a, int ovr, int bind)
 123 {
 124         unsigned h;
 125         int ret = 0, err;
 126         struct rtattr *tb[TCA_POLICE_MAX];
 127         struct tc_police *parm;
 128         struct tcf_police *police;
 129         struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
 130         int size;
 131
 132         if (rta == NULL || rtattr_parse_nested(tb, TCA_POLICE_MAX, rta) < 0)
 133                 return -EINVAL;
 134
 135         if (tb[TCA_POLICE_TBF-1] == NULL)
 136                 return -EINVAL;
 137         size = RTA_PAYLOAD(tb[TCA_POLICE_TBF-1]);
 138         if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
 139                 return -EINVAL;
 140         parm = RTA_DATA(tb[TCA_POLICE_TBF-1]);
 141
 142         if (tb[TCA_POLICE_RESULT-1] != NULL &&
 143             RTA_PAYLOAD(tb[TCA_POLICE_RESULT-1]) != sizeof(u32))
 144                 return -EINVAL;
 145         if (tb[TCA_POLICE_RESULT-1] != NULL &&
 146             RTA_PAYLOAD(tb[TCA_POLICE_RESULT-1]) != sizeof(u32))
 147                 return -EINVAL;
 148
 149         if (parm->index) {
 150                 struct tcf_common *pc;
 151
 152                 pc = tcf_hash_lookup(parm->index, &police_hash_info);
 153                 if (pc != NULL) {
 154                         a->priv = pc;
 155                         police = to_police(pc);
 156                         if (bind) {
 157                                 police->tcf_bindcnt += 1;
 158                                 police->tcf_refcnt += 1;
 159                         }
 160                         if (ovr)
 161                                 goto override;
 162                         return ret;
 163                 }
 164         }
 165
 166         police = kzalloc(sizeof(*police), GFP_KERNEL);
 167         if (police == NULL)
 168                 return -ENOMEM;
 169         ret = ACT_P_CREATED;
 170         police->tcf_refcnt = 1;
 171         spin_lock_init(&police->tcf_lock);
 172         if (bind)
 173                 police->tcf_bindcnt = 1;
 174 override:
 175         if (parm->rate.rate) {
 176                 err = -ENOMEM;
 177                 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE-1]);
 178                 if (R_tab == NULL)
 179                         goto failure;
 180                 if (parm->peakrate.rate) {
 181                         P_tab = qdisc_get_rtab(&parm->peakrate,
 182                                                tb[TCA_POLICE_PEAKRATE-1]);
 183                         if (P_tab == NULL) {
 184                                 qdisc_put_rtab(R_tab);
 185                                 goto failure;
 186                         }
 187                 }
 188         }
 189         /* No failure allowed after this point */
 190         spin_lock_bh(&police->tcf_lock);
 191         if (R_tab != NULL) {
 192                 qdisc_put_rtab(police->tcfp_R_tab);
 193                 police->tcfp_R_tab = R_tab;
 194         }
 195         if (P_tab != NULL) {
 196                 qdisc_put_rtab(police->tcfp_P_tab);
 197                 police->tcfp_P_tab = P_tab;
 198         }
 199
 200         if (tb[TCA_POLICE_RESULT-1])
 201                 police->tcfp_result = *(u32*)RTA_DATA(tb[TCA_POLICE_RESULT-1]);
 202         police->tcfp_toks = police->tcfp_burst = parm->burst;
 203         police->tcfp_mtu = parm->mtu;
 204         if (police->tcfp_mtu == 0) {
 205                 police->tcfp_mtu = ~0;
 206                 if (police->tcfp_R_tab)
 207                         police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log;
 208         }
 209         if (police->tcfp_P_tab)
 210                 police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu);
 211         police->tcf_action = parm->action;
 212
 213         if (tb[TCA_POLICE_AVRATE-1])
 214                 police->tcfp_ewma_rate =
 215                         *(u32*)RTA_DATA(tb[TCA_POLICE_AVRATE-1]);
 216         if (est)
 217                 gen_replace_estimator(&police->tcf_bstats,
 218                                       &police->tcf_rate_est,
 219                                       &police->tcf_lock, est);
 220
 221         spin_unlock_bh(&police->tcf_lock);
 222         if (ret != ACT_P_CREATED)
 223                 return ret;
 224
 225         police->tcfp_t_c = psched_get_time();
 226         police->tcf_index = parm->index ? parm->index :
 227                 tcf_hash_new_index(&police_idx_gen, &police_hash_info);
 228         h = tcf_hash(police->tcf_index, POL_TAB_MASK);
 229         write_lock_bh(&police_lock);
 230         police->tcf_next = tcf_police_ht[h];
 231         tcf_police_ht[h] = &police->common;
 232         write_unlock_bh(&police_lock);
 233
 234         a->priv = police;
 235         return ret;
 236
 237 failure:
 238         if (ret == ACT_P_CREATED)
 239                 kfree(police);
 240         return err;
 241 }
 242
 243 static int tcf_act_police_cleanup(struct tc_action *a, int bind)
 244 {
 245         struct tcf_police *p = a->priv;
 246         int ret = 0;
 247
 248         if (p != NULL) {
 249                 if (bind)
 250                         p->tcf_bindcnt--;
 251
 252                 p->tcf_refcnt--;
 253                 if (p->tcf_refcnt <= 0 && !p->tcf_bindcnt) {
 254                         tcf_police_destroy(p);
 255                         ret = 1;
 256                 }
 257         }
 258         return ret;
 259 }
 260
 261 static int tcf_act_police(struct sk_buff *skb, struct tc_action *a,
 262                           struct tcf_result *res)
 263 {
 264         struct tcf_police *police = a->priv;
 265         psched_time_t now;
 266         long toks;
 267         long ptoks = 0;
 268
 269         spin_lock(&police->tcf_lock);
 270
 271         police->tcf_bstats.bytes += skb->len;
 272         police->tcf_bstats.packets++;
 273
 274         if (police->tcfp_ewma_rate &&
 275             police->tcf_rate_est.bps >= police->tcfp_ewma_rate) {
 276                 police->tcf_qstats.overlimits++;
 277                 spin_unlock(&police->tcf_lock);
 278                 return police->tcf_action;
 279         }
 280
 281         if (skb->len <= police->tcfp_mtu) {
 282                 if (police->tcfp_R_tab == NULL) {
 283                         spin_unlock(&police->tcf_lock);
 284                         return police->tcfp_result;
 285                 }
 286
 287                 now = psched_get_time();
 288                 toks = psched_tdiff_bounded(now, police->tcfp_t_c,
 289                                             police->tcfp_burst);
 290                 if (police->tcfp_P_tab) {
 291                         ptoks = toks + police->tcfp_ptoks;
 292                         if (ptoks > (long)L2T_P(police, police->tcfp_mtu))
 293                                 ptoks = (long)L2T_P(police, police->tcfp_mtu);
 294                         ptoks -= L2T_P(police, skb->len);
 295                 }
 296                 toks += police->tcfp_toks;
 297                 if (toks > (long)police->tcfp_burst)
 298                         toks = police->tcfp_burst;
 299                 toks -= L2T(police, skb->len);
 300                 if ((toks|ptoks) >= 0) {
 301                         police->tcfp_t_c = now;
 302                         police->tcfp_toks = toks;
 303                         police->tcfp_ptoks = ptoks;
 304                         spin_unlock(&police->tcf_lock);
 305                         return police->tcfp_result;
 306                 }
 307         }
 308
 309         police->tcf_qstats.overlimits++;
 310         spin_unlock(&police->tcf_lock);
 311         return police->tcf_action;
 312 }
 313
 314 static int
 315 tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 316 {
 317         unsigned char *b = skb_tail_pointer(skb);
 318         struct tcf_police *police = a->priv;
 319         struct tc_police opt;
 320
 321         opt.index = police->tcf_index;
 322         opt.action = police->tcf_action;
 323         opt.mtu = police->tcfp_mtu;
 324         opt.burst = police->tcfp_burst;
 325         opt.refcnt = police->tcf_refcnt - ref;
 326         opt.bindcnt = police->tcf_bindcnt - bind;
 327         if (police->tcfp_R_tab)
 328                 opt.rate = police->tcfp_R_tab->rate;
 329         else
 330                 memset(&opt.rate, 0, sizeof(opt.rate));
 331         if (police->tcfp_P_tab)
 332                 opt.peakrate = police->tcfp_P_tab->rate;
 333         else
 334                 memset(&opt.peakrate, 0, sizeof(opt.peakrate));
 335         RTA_PUT(skb, TCA_POLICE_TBF, sizeof(opt), &opt);
 336         if (police->tcfp_result)
 337                 RTA_PUT(skb, TCA_POLICE_RESULT, sizeof(int),
 338                         &police->tcfp_result);
 339         if (police->tcfp_ewma_rate)
 340                 RTA_PUT(skb, TCA_POLICE_AVRATE, 4, &police->tcfp_ewma_rate);
 341         return skb->len;
 342
 343 rtattr_failure:
 344         nlmsg_trim(skb, b);
 345         return -1;
 346 }
 347
 348 MODULE_AUTHOR("Alexey Kuznetsov");
 349 MODULE_DESCRIPTION("Policing actions");
 350 MODULE_LICENSE("GPL");
 351
 352 static struct tc_action_ops act_police_ops = {
 353         .kind           =       "police",
 354         .hinfo          =       &police_hash_info,
 355         .type           =       TCA_ID_POLICE,
 356         .capab          =       TCA_CAP_NONE,
 357         .owner          =       THIS_MODULE,
 358         .act            =       tcf_act_police,
 359         .dump           =       tcf_act_police_dump,
 360         .cleanup        =       tcf_act_police_cleanup,
 361         .lookup         =       tcf_hash_search,
 362         .init           =       tcf_act_police_locate,
 363         .walk           =       tcf_act_police_walker
 364 };
 365
 366 static int __init
 367 police_init_module(void)
 368 {
 369         return tcf_register_action(&act_police_ops);
 370 }
 371
 372 static void __exit
 373 police_cleanup_module(void)
 374 {
 375         tcf_unregister_action(&act_police_ops);
 376 }
 377
 378 module_init(police_init_module);
 379 module_exit(police_cleanup_module);