SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/sched/sch_gred.c

   1 /*
   2  * net/sched/sch_gred.c Generic Random Early Detection queue.
   3  *
   4  *
   5  *              This program is free software; you can redistribute it and/or
   6  *              modify it under the terms of the GNU General Public License
   7  *              as published by the Free Software Foundation; either version
   8  *              2 of the License, or (at your option) any later version.
   9  *
  10  * Authors:    J Hadi Salim (hadi@cyberus.ca) 1998-2002
  11  *
  12  *             991129: -  Bug fix with grio mode
  13  *                     - a better sing. AvgQ mode with Grio(WRED)
  14  *                     - A finer grained VQ dequeue based on sugestion
  15  *                       from Ren Liu
  16  *                     - More error checks
  17  *
  18  *  For all the glorious comments look at include/net/red.h
  19  */
  20
  21 #include <linux/config.h>
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/kernel.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/skbuff.h>
  27 #include <net/pkt_sched.h>
  28 #include <net/red.h>
  29
  30 #define GRED_DEF_PRIO (MAX_DPs / 2)
  31 #define GRED_VQ_MASK (MAX_DPs - 1)
  32
  33 struct gred_sched_data;
  34 struct gred_sched;
  35
  36 struct gred_sched_data
  37 {
  38         u32             limit;          /* HARD maximal queue length    */
  39         u32             DP;             /* the drop pramaters */
  40         u32             bytesin;        /* bytes seen on virtualQ so far*/
  41         u32             packetsin;      /* packets seen on virtualQ so far*/
  42         u32             backlog;        /* bytes on the virtualQ */
  43         u8              prio;           /* the prio of this vq */
  44
  45         struct red_parms parms;
  46         struct red_stats stats;
  47 };
  48
  49 enum {
  50         GRED_WRED_MODE = 1,
  51         GRED_RIO_MODE,
  52 };
  53
  54 struct gred_sched
  55 {
  56         struct gred_sched_data *tab[MAX_DPs];
  57         unsigned long   flags;
  58         u32             DPs;
  59         u32             def;
  60         struct red_parms wred_set;
  61 };
  62
  63 static inline int gred_wred_mode(struct gred_sched *table)
  64 {
  65         return test_bit(GRED_WRED_MODE, &table->flags);
  66 }
  67
  68 static inline void gred_enable_wred_mode(struct gred_sched *table)
  69 {
  70         __set_bit(GRED_WRED_MODE, &table->flags);
  71 }
  72
  73 static inline void gred_disable_wred_mode(struct gred_sched *table)
  74 {
  75         __clear_bit(GRED_WRED_MODE, &table->flags);
  76 }
  77
  78 static inline int gred_rio_mode(struct gred_sched *table)
  79 {
  80         return test_bit(GRED_RIO_MODE, &table->flags);
  81 }
  82
  83 static inline void gred_enable_rio_mode(struct gred_sched *table)
  84 {
  85         __set_bit(GRED_RIO_MODE, &table->flags);
  86 }
  87
  88 static inline void gred_disable_rio_mode(struct gred_sched *table)
  89 {
  90         __clear_bit(GRED_RIO_MODE, &table->flags);
  91 }
  92
  93 static inline int gred_wred_mode_check(struct Qdisc *sch)
  94 {
  95         struct gred_sched *table = qdisc_priv(sch);
  96         int i;
  97
  98         /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
  99         for (i = 0; i < table->DPs; i++) {
 100                 struct gred_sched_data *q = table->tab[i];
 101                 int n;
 102
 103                 if (q == NULL)
 104                         continue;
 105
 106                 for (n = 0; n < table->DPs; n++)
 107                         if (table->tab[n] && table->tab[n] != q &&
 108                             table->tab[n]->prio == q->prio)
 109                                 return 1;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static inline unsigned int gred_backlog(struct gred_sched *table,
 116                                         struct gred_sched_data *q,
 117                                         struct Qdisc *sch)
 118 {
 119         if (gred_wred_mode(table))
 120                 return sch->qstats.backlog;
 121         else
 122                 return q->backlog;
 123 }
 124
 125 static inline u16 tc_index_to_dp(struct sk_buff *skb)
 126 {
 127         return skb->tc_index & GRED_VQ_MASK;
 128 }
 129
 130 static inline void gred_load_wred_set(struct gred_sched *table,
 131                                       struct gred_sched_data *q)
 132 {
 133         q->parms.qavg = table->wred_set.qavg;
 134         q->parms.qidlestart = table->wred_set.qidlestart;
 135 }
 136
 137 static inline void gred_store_wred_set(struct gred_sched *table,
 138                                        struct gred_sched_data *q)
 139 {
 140         table->wred_set.qavg = q->parms.qavg;
 141 }
 142
 143 static int gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 144 {
 145         struct gred_sched_data *q=NULL;
 146         struct gred_sched *t= qdisc_priv(sch);
 147         unsigned long qavg = 0;
 148         u16 dp = tc_index_to_dp(skb);
 149
 150         if (dp >= t->DPs  || (q = t->tab[dp]) == NULL) {
 151                 dp = t->def;
 152
 153                 if ((q = t->tab[dp]) == NULL) {
 154                         /* Pass through packets not assigned to a DP
 155                          * if no default DP has been configured. This
 156                          * allows for DP flows to be left untouched.
 157                          */
 158                         if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
 159                                 return qdisc_enqueue_tail(skb, sch);
 160                         else
 161                                 goto drop;
 162                 }
 163
 164                 /* fix tc_index? --could be controvesial but needed for
 165                    requeueing */
 166                 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
 167         }
 168
 169         /* sum up all the qaves of prios <= to ours to get the new qave */
 170         if (!gred_wred_mode(t) && gred_rio_mode(t)) {
 171                 int i;
 172
 173                 for (i = 0; i < t->DPs; i++) {
 174                         if (t->tab[i] && t->tab[i]->prio < q->prio &&
 175                             !red_is_idling(&t->tab[i]->parms))
 176                                 qavg +=t->tab[i]->parms.qavg;
 177                 }
 178
 179         }
 180
 181         q->packetsin++;
 182         q->bytesin += skb->len;
 183
 184         if (gred_wred_mode(t))
 185                 gred_load_wred_set(t, q);
 186
 187         q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
 188
 189         if (red_is_idling(&q->parms))
 190                 red_end_of_idle_period(&q->parms);
 191
 192         if (gred_wred_mode(t))
 193                 gred_store_wred_set(t, q);
 194
 195         switch (red_action(&q->parms, q->parms.qavg + qavg)) {
 196                 case RED_DONT_MARK:
 197                         break;
 198
 199                 case RED_PROB_MARK:
 200                         sch->qstats.overlimits++;
 201                         q->stats.prob_drop++;
 202                         goto congestion_drop;
 203
 204                 case RED_HARD_MARK:
 205                         sch->qstats.overlimits++;
 206                         q->stats.forced_drop++;
 207                         goto congestion_drop;
 208         }
 209
 210         if (q->backlog + skb->len <= q->limit) {
 211                 q->backlog += skb->len;
 212                 return qdisc_enqueue_tail(skb, sch);
 213         }
 214
 215         q->stats.pdrop++;
 216 drop:
 217         return qdisc_drop(skb, sch);
 218
 219 congestion_drop:
 220         qdisc_drop(skb, sch);
 221         return NET_XMIT_CN;
 222 }
 223
 224 static int gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
 225 {
 226         struct gred_sched *t = qdisc_priv(sch);
 227         struct gred_sched_data *q;
 228         u16 dp = tc_index_to_dp(skb);
 229
 230         if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 231                 if (net_ratelimit())
 232                         printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
 233                                "for requeue, screwing up backlog.\n",
 234                                tc_index_to_dp(skb));
 235         } else {
 236                 if (red_is_idling(&q->parms))
 237                         red_end_of_idle_period(&q->parms);
 238                 q->backlog += skb->len;
 239         }
 240
 241         return qdisc_requeue(skb, sch);
 242 }
 243
 244 static struct sk_buff *gred_dequeue(struct Qdisc* sch)
 245 {
 246         struct sk_buff *skb;
 247         struct gred_sched *t = qdisc_priv(sch);
 248
 249         skb = qdisc_dequeue_head(sch);
 250
 251         if (skb) {
 252                 struct gred_sched_data *q;
 253                 u16 dp = tc_index_to_dp(skb);
 254
 255                 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 256                         if (net_ratelimit())
 257                                 printk(KERN_WARNING "GRED: Unable to relocate "
 258                                        "VQ 0x%x after dequeue, screwing up "
 259                                        "backlog.\n", tc_index_to_dp(skb));
 260                 } else {
 261                         q->backlog -= skb->len;
 262
 263                         if (!q->backlog && !gred_wred_mode(t))
 264                                 red_start_of_idle_period(&q->parms);
 265                 }
 266
 267                 return skb;
 268         }
 269
 270         if (gred_wred_mode(t))
 271                 red_start_of_idle_period(&t->wred_set);
 272
 273         return NULL;
 274 }
 275
 276 static unsigned int gred_drop(struct Qdisc* sch)
 277 {
 278         struct sk_buff *skb;
 279         struct gred_sched *t = qdisc_priv(sch);
 280
 281         skb = qdisc_dequeue_tail(sch);
 282         if (skb) {
 283                 unsigned int len = skb->len;
 284                 struct gred_sched_data *q;
 285                 u16 dp = tc_index_to_dp(skb);
 286
 287                 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 288                         if (net_ratelimit())
 289                                 printk(KERN_WARNING "GRED: Unable to relocate "
 290                                        "VQ 0x%x while dropping, screwing up "
 291                                        "backlog.\n", tc_index_to_dp(skb));
 292                 } else {
 293                         q->backlog -= len;
 294                         q->stats.other++;
 295
 296                         if (!q->backlog && !gred_wred_mode(t))
 297                                 red_start_of_idle_period(&q->parms);
 298                 }
 299
 300                 qdisc_drop(skb, sch);
 301                 return len;
 302         }
 303
 304         if (gred_wred_mode(t))
 305                 red_start_of_idle_period(&t->wred_set);
 306
 307         return 0;
 308
 309 }
 310
 311 static void gred_reset(struct Qdisc* sch)
 312 {
 313         int i;
 314         struct gred_sched *t = qdisc_priv(sch);
 315
 316         qdisc_reset_queue(sch);
 317
 318         for (i = 0; i < t->DPs; i++) {
 319                 struct gred_sched_data *q = t->tab[i];
 320
 321                 if (!q)
 322                         continue;
 323
 324                 red_restart(&q->parms);
 325                 q->backlog = 0;
 326         }
 327 }
 328
 329 static inline void gred_destroy_vq(struct gred_sched_data *q)
 330 {
 331         kfree(q);
 332 }
 333
 334 static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
 335 {
 336         struct gred_sched *table = qdisc_priv(sch);
 337         struct tc_gred_sopt *sopt;
 338         int i;
 339
 340         if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
 341                 return -EINVAL;
 342
 343         sopt = RTA_DATA(dps);
 344
 345         if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
 346                 return -EINVAL;
 347
 348         sch_tree_lock(sch);
 349         table->DPs = sopt->DPs;
 350         table->def = sopt->def_DP;
 351
 352         /*
 353          * Every entry point to GRED is synchronized with the above code
 354          * and the DP is checked against DPs, i.e. shadowed VQs can no
 355          * longer be found so we can unlock right here.
 356          */
 357         sch_tree_unlock(sch);
 358
 359         if (sopt->grio) {
 360                 gred_enable_rio_mode(table);
 361                 gred_disable_wred_mode(table);
 362                 if (gred_wred_mode_check(sch))
 363                         gred_enable_wred_mode(table);
 364         } else {
 365                 gred_disable_rio_mode(table);
 366                 gred_disable_wred_mode(table);
 367         }
 368
 369         for (i = table->DPs; i < MAX_DPs; i++) {
 370                 if (table->tab[i]) {
 371                         printk(KERN_WARNING "GRED: Warning: Destroying "
 372                                "shadowed VQ 0x%x\n", i);
 373                         gred_destroy_vq(table->tab[i]);
 374                         table->tab[i] = NULL;
 375                 }
 376         }
 377
 378         return 0;
 379 }
 380
 381 static inline int gred_change_vq(struct Qdisc *sch, int dp,
 382                                  struct tc_gred_qopt *ctl, int prio, u8 *stab)
 383 {
 384         struct gred_sched *table = qdisc_priv(sch);
 385         struct gred_sched_data *q;
 386
 387         if (table->tab[dp] == NULL) {
 388                 table->tab[dp] = kmalloc(sizeof(*q), GFP_KERNEL);
 389                 if (table->tab[dp] == NULL)
 390                         return -ENOMEM;
 391                 memset(table->tab[dp], 0, sizeof(*q));
 392         }
 393
 394         q = table->tab[dp];
 395         q->DP = dp;
 396         q->prio = prio;
 397         q->limit = ctl->limit;
 398
 399         if (q->backlog == 0)
 400                 red_end_of_idle_period(&q->parms);
 401
 402         red_set_parms(&q->parms,
 403                       ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
 404                       ctl->Scell_log, stab);
 405
 406         return 0;
 407 }
 408
 409 static int gred_change(struct Qdisc *sch, struct rtattr *opt)
 410 {
 411         struct gred_sched *table = qdisc_priv(sch);
 412         struct tc_gred_qopt *ctl;
 413         struct rtattr *tb[TCA_GRED_MAX];
 414         int err = -EINVAL, prio = GRED_DEF_PRIO;
 415         u8 *stab;
 416
 417         if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
 418                 return -EINVAL;
 419
 420         if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
 421                 return gred_change_table_def(sch, opt);
 422
 423         if (tb[TCA_GRED_PARMS-1] == NULL ||
 424             RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
 425             tb[TCA_GRED_STAB-1] == NULL ||
 426             RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
 427                 return -EINVAL;
 428
 429         ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
 430         stab = RTA_DATA(tb[TCA_GRED_STAB-1]);
 431
 432         if (ctl->DP >= table->DPs)
 433                 goto errout;
 434
 435         if (gred_rio_mode(table)) {
 436                 if (ctl->prio == 0) {
 437                         int def_prio = GRED_DEF_PRIO;
 438
 439                         if (table->tab[table->def])
 440                                 def_prio = table->tab[table->def]->prio;
 441
 442                         printk(KERN_DEBUG "GRED: DP %u does not have a prio "
 443                                "setting default to %d\n", ctl->DP, def_prio);
 444
 445                         prio = def_prio;
 446                 } else
 447                         prio = ctl->prio;
 448         }
 449
 450         sch_tree_lock(sch);
 451
 452         err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
 453         if (err < 0)
 454                 goto errout_locked;
 455
 456         if (gred_rio_mode(table)) {
 457                 gred_disable_wred_mode(table);
 458                 if (gred_wred_mode_check(sch))
 459                         gred_enable_wred_mode(table);
 460         }
 461
 462         err = 0;
 463
 464 errout_locked:
 465         sch_tree_unlock(sch);
 466 errout:
 467         return err;
 468 }
 469
 470 static int gred_init(struct Qdisc *sch, struct rtattr *opt)
 471 {
 472         struct rtattr *tb[TCA_GRED_MAX];
 473
 474         if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
 475                 return -EINVAL;
 476
 477         if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
 478                 return -EINVAL;
 479
 480         return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
 481 }
 482
 483 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
 484 {
 485         struct gred_sched *table = qdisc_priv(sch);
 486         struct rtattr *parms, *opts = NULL;
 487         int i;
 488         struct tc_gred_sopt sopt = {
 489                 .DPs    = table->DPs,
 490                 .def_DP = table->def,
 491                 .grio   = gred_rio_mode(table),
 492         };
 493
 494         opts = RTA_NEST(skb, TCA_OPTIONS);
 495         RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
 496         parms = RTA_NEST(skb, TCA_GRED_PARMS);
 497
 498         for (i = 0; i < MAX_DPs; i++) {
 499                 struct gred_sched_data *q = table->tab[i];
 500                 struct tc_gred_qopt opt;
 501
 502                 memset(&opt, 0, sizeof(opt));
 503
 504                 if (!q) {
 505                         /* hack -- fix at some point with proper message
 506                            This is how we indicate to tc that there is no VQ
 507                            at this DP */
 508
 509                         opt.DP = MAX_DPs + i;
 510                         goto append_opt;
 511                 }
 512
 513                 opt.limit       = q->limit;
 514                 opt.DP          = q->DP;
 515                 opt.backlog     = q->backlog;
 516                 opt.prio        = q->prio;
 517                 opt.qth_min     = q->parms.qth_min >> q->parms.Wlog;
 518                 opt.qth_max     = q->parms.qth_max >> q->parms.Wlog;
 519                 opt.Wlog        = q->parms.Wlog;
 520                 opt.Plog        = q->parms.Plog;
 521                 opt.Scell_log   = q->parms.Scell_log;
 522                 opt.other       = q->stats.other;
 523                 opt.early       = q->stats.prob_drop;
 524                 opt.forced      = q->stats.forced_drop;
 525                 opt.pdrop       = q->stats.pdrop;
 526                 opt.packets     = q->packetsin;
 527                 opt.bytesin     = q->bytesin;
 528
 529                 if (gred_wred_mode(table)) {
 530                         q->parms.qidlestart =
 531                                 table->tab[table->def]->parms.qidlestart;
 532                         q->parms.qavg = table->tab[table->def]->parms.qavg;
 533                 }
 534
 535                 opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
 536
 537 append_opt:
 538                 RTA_APPEND(skb, sizeof(opt), &opt);
 539         }
 540
 541         RTA_NEST_END(skb, parms);
 542
 543         return RTA_NEST_END(skb, opts);
 544
 545 rtattr_failure:
 546         return RTA_NEST_CANCEL(skb, opts);
 547 }
 548
 549 static void gred_destroy(struct Qdisc *sch)
 550 {
 551         struct gred_sched *table = qdisc_priv(sch);
 552         int i;
 553
 554         for (i = 0; i < table->DPs; i++) {
 555                 if (table->tab[i])
 556                         gred_destroy_vq(table->tab[i]);
 557         }
 558 }
 559
 560 static struct Qdisc_ops gred_qdisc_ops = {
 561         .id             =       "gred",
 562         .priv_size      =       sizeof(struct gred_sched),
 563         .enqueue        =       gred_enqueue,
 564         .dequeue        =       gred_dequeue,
 565         .requeue        =       gred_requeue,
 566         .drop           =       gred_drop,
 567         .init           =       gred_init,
 568         .reset          =       gred_reset,
 569         .destroy        =       gred_destroy,
 570         .change         =       gred_change,
 571         .dump           =       gred_dump,
 572         .owner          =       THIS_MODULE,
 573 };
 574
 575 static int __init gred_module_init(void)
 576 {
 577         return register_qdisc(&gred_qdisc_ops);
 578 }
 579
 580 static void __exit gred_module_exit(void)
 581 {
 582         unregister_qdisc(&gred_qdisc_ops);
 583 }
 584
 585 module_init(gred_module_init)
 586 module_exit(gred_module_exit)
 587
 588 MODULE_LICENSE("GPL");