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  *
  19  *
  20  *  For all the glorious comments look at Alexey's sch_red.c
  21  */
  22
  23 #include <linux/config.h>
  24 #include <linux/module.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/system.h>
  27 #include <linux/bitops.h>
  28 #include <linux/types.h>
  29 #include <linux/kernel.h>
  30 #include <linux/sched.h>
  31 #include <linux/string.h>
  32 #include <linux/mm.h>
  33 #include <linux/socket.h>
  34 #include <linux/sockios.h>
  35 #include <linux/in.h>
  36 #include <linux/errno.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/if_ether.h>
  39 #include <linux/inet.h>
  40 #include <linux/netdevice.h>
  41 #include <linux/etherdevice.h>
  42 #include <linux/notifier.h>
  43 #include <net/ip.h>
  44 #include <net/route.h>
  45 #include <linux/skbuff.h>
  46 #include <net/sock.h>
  47 #include <net/pkt_sched.h>
  48 #include <net/red.h>
  49
  50 #if 1 /* control */
  51 #define DPRINTK(format,args...) printk(KERN_DEBUG format,##args)
  52 #else
  53 #define DPRINTK(format,args...)
  54 #endif
  55
  56 #if 0 /* data */
  57 #define D2PRINTK(format,args...) printk(KERN_DEBUG format,##args)
  58 #else
  59 #define D2PRINTK(format,args...)
  60 #endif
  61
  62 #define GRED_DEF_PRIO (MAX_DPs / 2)
  63 #define GRED_VQ_MASK (MAX_DPs - 1)
  64
  65 struct gred_sched_data;
  66 struct gred_sched;
  67
  68 struct gred_sched_data
  69 {
  70         u32             limit;          /* HARD maximal queue length    */
  71         u32             DP;             /* the drop pramaters */
  72         u32             bytesin;        /* bytes seen on virtualQ so far*/
  73         u32             packetsin;      /* packets seen on virtualQ so far*/
  74         u32             backlog;        /* bytes on the virtualQ */
  75         u8              prio;        /* the prio of this vq */
  76
  77         struct red_parms parms;
  78         struct red_stats stats;
  79 };
  80
  81 enum {
  82         GRED_WRED_MODE = 1,
  83         GRED_RIO_MODE,
  84 };
  85
  86 struct gred_sched
  87 {
  88         struct gred_sched_data *tab[MAX_DPs];
  89         unsigned long   flags;
  90         u32             DPs;
  91         u32             def;
  92         u8              initd;
  93 };
  94
  95 static inline int gred_wred_mode(struct gred_sched *table)
  96 {
  97         return test_bit(GRED_WRED_MODE, &table->flags);
  98 }
  99
 100 static inline void gred_enable_wred_mode(struct gred_sched *table)
 101 {
 102         __set_bit(GRED_WRED_MODE, &table->flags);
 103 }
 104
 105 static inline void gred_disable_wred_mode(struct gred_sched *table)
 106 {
 107         __clear_bit(GRED_WRED_MODE, &table->flags);
 108 }
 109
 110 static inline int gred_rio_mode(struct gred_sched *table)
 111 {
 112         return test_bit(GRED_RIO_MODE, &table->flags);
 113 }
 114
 115 static inline void gred_enable_rio_mode(struct gred_sched *table)
 116 {
 117         __set_bit(GRED_RIO_MODE, &table->flags);
 118 }
 119
 120 static inline void gred_disable_rio_mode(struct gred_sched *table)
 121 {
 122         __clear_bit(GRED_RIO_MODE, &table->flags);
 123 }
 124
 125 static inline int gred_wred_mode_check(struct Qdisc *sch)
 126 {
 127         struct gred_sched *table = qdisc_priv(sch);
 128         int i;
 129
 130         /* Really ugly O(n^2) but shouldn't be necessary too frequent. */
 131         for (i = 0; i < table->DPs; i++) {
 132                 struct gred_sched_data *q = table->tab[i];
 133                 int n;
 134
 135                 if (q == NULL)
 136                         continue;
 137
 138                 for (n = 0; n < table->DPs; n++)
 139                         if (table->tab[n] && table->tab[n] != q &&
 140                             table->tab[n]->prio == q->prio)
 141                                 return 1;
 142         }
 143
 144         return 0;
 145 }
 146
 147 static inline unsigned int gred_backlog(struct gred_sched *table,
 148                                         struct gred_sched_data *q,
 149                                         struct Qdisc *sch)
 150 {
 151         if (gred_wred_mode(table))
 152                 return sch->qstats.backlog;
 153         else
 154                 return q->backlog;
 155 }
 156
 157 static inline u16 tc_index_to_dp(struct sk_buff *skb)
 158 {
 159         return skb->tc_index & GRED_VQ_MASK;
 160 }
 161
 162 static int
 163 gred_enqueue(struct sk_buff *skb, struct Qdisc* sch)
 164 {
 165         struct gred_sched_data *q=NULL;
 166         struct gred_sched *t= qdisc_priv(sch);
 167         unsigned long qavg = 0;
 168         int i=0;
 169         u16 dp;
 170
 171         if (!t->initd && skb_queue_len(&sch->q) < (sch->dev->tx_queue_len ? : 1)) {
 172                 D2PRINTK("NO GRED Queues setup yet! Enqueued anyway\n");
 173                 goto do_enqueue;
 174         }
 175
 176         dp = tc_index_to_dp(skb);
 177
 178         if (dp >= t->DPs  || (q = t->tab[dp]) == NULL) {
 179                 dp = t->def;
 180
 181                 if ((q = t->tab[dp]) == NULL) {
 182                         /* Pass through packets not assigned to a DP
 183                          * if no default DP has been configured. This
 184                          * allows for DP flows to be left untouched.
 185                          */
 186                         if (skb_queue_len(&sch->q) < sch->dev->tx_queue_len)
 187                                 return qdisc_enqueue_tail(skb, sch);
 188                         else
 189                                 goto drop;
 190                 }
 191
 192                 /* fix tc_index? --could be controvesial but needed for
 193                    requeueing */
 194                 skb->tc_index = (skb->tc_index & ~GRED_VQ_MASK) | dp;
 195         }
 196
 197         /* sum up all the qaves of prios <= to ours to get the new qave*/
 198         if (!gred_wred_mode(t) && gred_rio_mode(t)) {
 199                 for (i=0;i<t->DPs;i++) {
 200                         if ((!t->tab[i]) || (i==q->DP))
 201                                 continue;
 202
 203                         if (t->tab[i]->prio < q->prio &&
 204                             !red_is_idling(&t->tab[i]->parms))
 205                                 qavg +=t->tab[i]->parms.qavg;
 206                 }
 207
 208         }
 209
 210         q->packetsin++;
 211         q->bytesin+=skb->len;
 212
 213         if (gred_wred_mode(t)) {
 214                 qavg = 0;
 215                 q->parms.qavg = t->tab[t->def]->parms.qavg;
 216                 q->parms.qidlestart = t->tab[t->def]->parms.qidlestart;
 217         }
 218
 219         q->parms.qavg = red_calc_qavg(&q->parms, gred_backlog(t, q, sch));
 220
 221         if (red_is_idling(&q->parms))
 222                 red_end_of_idle_period(&q->parms);
 223
 224         if (gred_wred_mode(t))
 225                 t->tab[t->def]->parms.qavg = q->parms.qavg;
 226
 227         switch (red_action(&q->parms, q->parms.qavg + qavg)) {
 228                 case RED_DONT_MARK:
 229                         break;
 230
 231                 case RED_PROB_MARK:
 232                         sch->qstats.overlimits++;
 233                         q->stats.prob_drop++;
 234                         goto congestion_drop;
 235
 236                 case RED_HARD_MARK:
 237                         sch->qstats.overlimits++;
 238                         q->stats.forced_drop++;
 239                         goto congestion_drop;
 240         }
 241
 242         if (q->backlog + skb->len <= q->limit) {
 243                 q->backlog += skb->len;
 244 do_enqueue:
 245                 return qdisc_enqueue_tail(skb, sch);
 246         }
 247
 248         q->stats.pdrop++;
 249 drop:
 250         return qdisc_drop(skb, sch);
 251
 252 congestion_drop:
 253         qdisc_drop(skb, sch);
 254         return NET_XMIT_CN;
 255 }
 256
 257 static int
 258 gred_requeue(struct sk_buff *skb, struct Qdisc* sch)
 259 {
 260         struct gred_sched *t = qdisc_priv(sch);
 261         struct gred_sched_data *q;
 262         u16 dp = tc_index_to_dp(skb);
 263
 264         if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 265                 if (net_ratelimit())
 266                         printk(KERN_WARNING "GRED: Unable to relocate VQ 0x%x "
 267                                "for requeue, screwing up backlog.\n",
 268                                tc_index_to_dp(skb));
 269         } else {
 270                 if (red_is_idling(&q->parms))
 271                         red_end_of_idle_period(&q->parms);
 272                 q->backlog += skb->len;
 273         }
 274
 275         return qdisc_requeue(skb, sch);
 276 }
 277
 278 static struct sk_buff *
 279 gred_dequeue(struct Qdisc* sch)
 280 {
 281         struct sk_buff *skb;
 282         struct gred_sched_data *q;
 283         struct gred_sched *t= qdisc_priv(sch);
 284
 285         skb = qdisc_dequeue_head(sch);
 286
 287         if (skb) {
 288                 u16 dp = tc_index_to_dp(skb);
 289
 290                 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 291                         if (net_ratelimit())
 292                                 printk(KERN_WARNING "GRED: Unable to relocate "
 293                                        "VQ 0x%x after dequeue, screwing up "
 294                                        "backlog.\n", tc_index_to_dp(skb));
 295                 } else {
 296                         q->backlog -= skb->len;
 297
 298                         if (!q->backlog && !gred_wred_mode(t))
 299                                 red_start_of_idle_period(&q->parms);
 300                 }
 301
 302                 return skb;
 303         }
 304
 305         if (gred_wred_mode(t)) {
 306                         q= t->tab[t->def];
 307                         if (!q)
 308                                 D2PRINTK("no default VQ set: Results will be "
 309                                        "screwed up\n");
 310                         else
 311                                 red_start_of_idle_period(&q->parms);
 312         }
 313
 314         return NULL;
 315 }
 316
 317 static unsigned int gred_drop(struct Qdisc* sch)
 318 {
 319         struct sk_buff *skb;
 320
 321         struct gred_sched_data *q;
 322         struct gred_sched *t= qdisc_priv(sch);
 323
 324         skb = qdisc_dequeue_tail(sch);
 325         if (skb) {
 326                 unsigned int len = skb->len;
 327                 u16 dp = tc_index_to_dp(skb);
 328
 329                 if (dp >= t->DPs || (q = t->tab[dp]) == NULL) {
 330                         if (net_ratelimit())
 331                                 printk(KERN_WARNING "GRED: Unable to relocate "
 332                                        "VQ 0x%x while dropping, screwing up "
 333                                        "backlog.\n", tc_index_to_dp(skb));
 334                 } else {
 335                         q->backlog -= len;
 336                         q->stats.other++;
 337
 338                         if (!q->backlog && !gred_wred_mode(t))
 339                                 red_start_of_idle_period(&q->parms);
 340                 }
 341
 342                 qdisc_drop(skb, sch);
 343                 return len;
 344         }
 345
 346         q=t->tab[t->def];
 347         if (!q) {
 348                 D2PRINTK("no default VQ set: Results might be screwed up\n");
 349                 return 0;
 350         }
 351
 352         red_start_of_idle_period(&q->parms);
 353         return 0;
 354
 355 }
 356
 357 static void gred_reset(struct Qdisc* sch)
 358 {
 359         int i;
 360         struct gred_sched_data *q;
 361         struct gred_sched *t= qdisc_priv(sch);
 362
 363         qdisc_reset_queue(sch);
 364
 365         for (i=0;i<t->DPs;i++) {
 366                 q= t->tab[i];
 367                 if (!q)
 368                         continue;
 369                 red_restart(&q->parms);
 370                 q->backlog = 0;
 371         }
 372 }
 373
 374 static inline void gred_destroy_vq(struct gred_sched_data *q)
 375 {
 376         kfree(q);
 377 }
 378
 379 static inline int gred_change_table_def(struct Qdisc *sch, struct rtattr *dps)
 380 {
 381         struct gred_sched *table = qdisc_priv(sch);
 382         struct tc_gred_sopt *sopt;
 383         int i;
 384
 385         if (dps == NULL || RTA_PAYLOAD(dps) < sizeof(*sopt))
 386                 return -EINVAL;
 387
 388         sopt = RTA_DATA(dps);
 389
 390         if (sopt->DPs > MAX_DPs || sopt->DPs == 0 || sopt->def_DP >= sopt->DPs)
 391                 return -EINVAL;
 392
 393         sch_tree_lock(sch);
 394         table->DPs = sopt->DPs;
 395         table->def = sopt->def_DP;
 396
 397         /*
 398          * Every entry point to GRED is synchronized with the above code
 399          * and the DP is checked against DPs, i.e. shadowed VQs can no
 400          * longer be found so we can unlock right here.
 401          */
 402         sch_tree_unlock(sch);
 403
 404         if (sopt->grio) {
 405                 gred_enable_rio_mode(table);
 406                 gred_disable_wred_mode(table);
 407                 if (gred_wred_mode_check(sch))
 408                         gred_enable_wred_mode(table);
 409         } else {
 410                 gred_disable_rio_mode(table);
 411                 gred_disable_wred_mode(table);
 412         }
 413
 414         for (i = table->DPs; i < MAX_DPs; i++) {
 415                 if (table->tab[i]) {
 416                         printk(KERN_WARNING "GRED: Warning: Destroying "
 417                                "shadowed VQ 0x%x\n", i);
 418                         gred_destroy_vq(table->tab[i]);
 419                         table->tab[i] = NULL;
 420                 }
 421         }
 422
 423         table->initd = 0;
 424
 425         return 0;
 426 }
 427
 428 static inline int gred_change_vq(struct Qdisc *sch, int dp,
 429                                  struct tc_gred_qopt *ctl, int prio, u8 *stab)
 430 {
 431         struct gred_sched *table = qdisc_priv(sch);
 432         struct gred_sched_data *q;
 433
 434         if (table->tab[dp] == NULL) {
 435                 table->tab[dp] = kmalloc(sizeof(*q), GFP_KERNEL);
 436                 if (table->tab[dp] == NULL)
 437                         return -ENOMEM;
 438                 memset(table->tab[dp], 0, sizeof(*q));
 439         }
 440
 441         q = table->tab[dp];
 442         q->DP = dp;
 443         q->prio = prio;
 444         q->limit = ctl->limit;
 445
 446         if (q->backlog == 0)
 447                 red_end_of_idle_period(&q->parms);
 448
 449         red_set_parms(&q->parms,
 450                       ctl->qth_min, ctl->qth_max, ctl->Wlog, ctl->Plog,
 451                       ctl->Scell_log, stab);
 452
 453         return 0;
 454 }
 455
 456 static int gred_change(struct Qdisc *sch, struct rtattr *opt)
 457 {
 458         struct gred_sched *table = qdisc_priv(sch);
 459         struct tc_gred_qopt *ctl;
 460         struct rtattr *tb[TCA_GRED_MAX];
 461         int err = -EINVAL, prio = GRED_DEF_PRIO;
 462         u8 *stab;
 463
 464         if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
 465                 return -EINVAL;
 466
 467         if (tb[TCA_GRED_PARMS-1] == NULL && tb[TCA_GRED_STAB-1] == NULL)
 468                 return gred_change_table_def(sch, opt);
 469
 470         if (tb[TCA_GRED_PARMS-1] == NULL ||
 471             RTA_PAYLOAD(tb[TCA_GRED_PARMS-1]) < sizeof(*ctl) ||
 472             tb[TCA_GRED_STAB-1] == NULL ||
 473             RTA_PAYLOAD(tb[TCA_GRED_STAB-1]) < 256)
 474                 return -EINVAL;
 475
 476         ctl = RTA_DATA(tb[TCA_GRED_PARMS-1]);
 477         stab = RTA_DATA(tb[TCA_GRED_STAB-1]);
 478
 479         if (ctl->DP >= table->DPs)
 480                 goto errout;
 481
 482         if (gred_rio_mode(table)) {
 483                 if (ctl->prio == 0) {
 484                         int def_prio = GRED_DEF_PRIO;
 485
 486                         if (table->tab[table->def])
 487                                 def_prio = table->tab[table->def]->prio;
 488
 489                         printk(KERN_DEBUG "GRED: DP %u does not have a prio "
 490                                "setting default to %d\n", ctl->DP, def_prio);
 491
 492                         prio = def_prio;
 493                 } else
 494                         prio = ctl->prio;
 495         }
 496
 497         sch_tree_lock(sch);
 498
 499         err = gred_change_vq(sch, ctl->DP, ctl, prio, stab);
 500         if (err < 0)
 501                 goto errout_locked;
 502
 503         if (table->tab[table->def] == NULL) {
 504                 if (gred_rio_mode(table))
 505                         prio = table->tab[ctl->DP]->prio;
 506
 507                 err = gred_change_vq(sch, table->def, ctl, prio, stab);
 508                 if (err < 0)
 509                         goto errout_locked;
 510         }
 511
 512         table->initd = 1;
 513
 514         if (gred_rio_mode(table)) {
 515                 gred_disable_wred_mode(table);
 516                 if (gred_wred_mode_check(sch))
 517                         gred_enable_wred_mode(table);
 518         }
 519
 520         err = 0;
 521
 522 errout_locked:
 523         sch_tree_unlock(sch);
 524 errout:
 525         return err;
 526 }
 527
 528 static int gred_init(struct Qdisc *sch, struct rtattr *opt)
 529 {
 530         struct rtattr *tb[TCA_GRED_MAX];
 531
 532         if (opt == NULL || rtattr_parse_nested(tb, TCA_GRED_MAX, opt))
 533                 return -EINVAL;
 534
 535         if (tb[TCA_GRED_PARMS-1] || tb[TCA_GRED_STAB-1])
 536                 return -EINVAL;
 537
 538         return gred_change_table_def(sch, tb[TCA_GRED_DPS-1]);
 539 }
 540
 541 static int gred_dump(struct Qdisc *sch, struct sk_buff *skb)
 542 {
 543         struct gred_sched *table = qdisc_priv(sch);
 544         struct rtattr *parms, *opts = NULL;
 545         int i;
 546         struct tc_gred_sopt sopt = {
 547                 .DPs    = table->DPs,
 548                 .def_DP = table->def,
 549                 .grio   = gred_rio_mode(table),
 550         };
 551
 552         opts = RTA_NEST(skb, TCA_OPTIONS);
 553         RTA_PUT(skb, TCA_GRED_DPS, sizeof(sopt), &sopt);
 554         parms = RTA_NEST(skb, TCA_GRED_PARMS);
 555
 556         for (i = 0; i < MAX_DPs; i++) {
 557                 struct gred_sched_data *q = table->tab[i];
 558                 struct tc_gred_qopt opt;
 559
 560                 memset(&opt, 0, sizeof(opt));
 561
 562                 if (!q) {
 563                         /* hack -- fix at some point with proper message
 564                            This is how we indicate to tc that there is no VQ
 565                            at this DP */
 566
 567                         opt.DP = MAX_DPs + i;
 568                         goto append_opt;
 569                 }
 570
 571                 opt.limit       = q->limit;
 572                 opt.DP          = q->DP;
 573                 opt.backlog     = q->backlog;
 574                 opt.prio        = q->prio;
 575                 opt.qth_min     = q->parms.qth_min >> q->parms.Wlog;
 576                 opt.qth_max     = q->parms.qth_max >> q->parms.Wlog;
 577                 opt.Wlog        = q->parms.Wlog;
 578                 opt.Plog        = q->parms.Plog;
 579                 opt.Scell_log   = q->parms.Scell_log;
 580                 opt.other       = q->stats.other;
 581                 opt.early       = q->stats.prob_drop;
 582                 opt.forced      = q->stats.forced_drop;
 583                 opt.pdrop       = q->stats.pdrop;
 584                 opt.packets     = q->packetsin;
 585                 opt.bytesin     = q->bytesin;
 586
 587                 if (gred_wred_mode(table)) {
 588                         q->parms.qidlestart =
 589                                 table->tab[table->def]->parms.qidlestart;
 590                         q->parms.qavg = table->tab[table->def]->parms.qavg;
 591                 }
 592
 593                 opt.qave = red_calc_qavg(&q->parms, q->parms.qavg);
 594
 595 append_opt:
 596                 RTA_APPEND(skb, sizeof(opt), &opt);
 597         }
 598
 599         RTA_NEST_END(skb, parms);
 600
 601         return RTA_NEST_END(skb, opts);
 602
 603 rtattr_failure:
 604         return RTA_NEST_CANCEL(skb, opts);
 605 }
 606
 607 static void gred_destroy(struct Qdisc *sch)
 608 {
 609         struct gred_sched *table = qdisc_priv(sch);
 610         int i;
 611
 612         for (i = 0;i < table->DPs; i++) {
 613                 if (table->tab[i])
 614                         gred_destroy_vq(table->tab[i]);
 615         }
 616 }
 617
 618 static struct Qdisc_ops gred_qdisc_ops = {
 619         .next           =       NULL,
 620         .cl_ops         =       NULL,
 621         .id             =       "gred",
 622         .priv_size      =       sizeof(struct gred_sched),
 623         .enqueue        =       gred_enqueue,
 624         .dequeue        =       gred_dequeue,
 625         .requeue        =       gred_requeue,
 626         .drop           =       gred_drop,
 627         .init           =       gred_init,
 628         .reset          =       gred_reset,
 629         .destroy        =       gred_destroy,
 630         .change         =       gred_change,
 631         .dump           =       gred_dump,
 632         .owner          =       THIS_MODULE,
 633 };
 634
 635 static int __init gred_module_init(void)
 636 {
 637         return register_qdisc(&gred_qdisc_ops);
 638 }
 639 static void __exit gred_module_exit(void)
 640 {
 641         unregister_qdisc(&gred_qdisc_ops);
 642 }
 643 module_init(gred_module_init)
 644 module_exit(gred_module_exit)
 645 MODULE_LICENSE("GPL");