net/sched/sch_prio.c

   1 /*
   2  * net/sched/sch_prio.c Simple 3-band priority "scheduler".
   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  * Fixes:       19990609: J Hadi Salim <hadi@nortelnetworks.com>:
  11  *              Init --  EINVAL when opt undefined
  12  */
  13
  14 #include <linux/module.h>
  15 #include <asm/uaccess.h>
  16 #include <asm/system.h>
  17 #include <linux/bitops.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/string.h>
  21 #include <linux/mm.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/in.h>
  25 #include <linux/errno.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/if_ether.h>
  28 #include <linux/inet.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/etherdevice.h>
  31 #include <linux/notifier.h>
  32 #include <net/ip.h>
  33 #include <net/route.h>
  34 #include <linux/skbuff.h>
  35 #include <net/sock.h>
  36 #include <net/pkt_sched.h>
  37
  38
  39 struct prio_sched_data
  40 {
  41         int bands;
  42         struct tcf_proto *filter_list;
  43         u8  prio2band[TC_PRIO_MAX+1];
  44         struct Qdisc *queues[TCQ_PRIO_BANDS];
  45 };
  46
  47
  48 static struct Qdisc *
  49 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
  50 {
  51         struct prio_sched_data *q = qdisc_priv(sch);
  52         u32 band = skb->priority;
  53         struct tcf_result res;
  54
  55         *qerr = NET_XMIT_BYPASS;
  56         if (TC_H_MAJ(skb->priority) != sch->handle) {
  57 #ifdef CONFIG_NET_CLS_ACT
  58                 switch (tc_classify(skb, q->filter_list, &res)) {
  59                 case TC_ACT_STOLEN:
  60                 case TC_ACT_QUEUED:
  61                         *qerr = NET_XMIT_SUCCESS;
  62                 case TC_ACT_SHOT:
  63                         return NULL;
  64                 };
  65
  66                 if (!q->filter_list ) {
  67 #else
  68                 if (!q->filter_list || tc_classify(skb, q->filter_list, &res)) {
  69 #endif
  70                         if (TC_H_MAJ(band))
  71                                 band = 0;
  72                         return q->queues[q->prio2band[band&TC_PRIO_MAX]];
  73                 }
  74                 band = res.classid;
  75         }
  76         band = TC_H_MIN(band) - 1;
  77         if (band > q->bands)
  78                 return q->queues[q->prio2band[0]];
  79
  80         return q->queues[band];
  81 }
  82
  83 static int
  84 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  85 {
  86         struct Qdisc *qdisc;
  87         int ret;
  88
  89         qdisc = prio_classify(skb, sch, &ret);
  90 #ifdef CONFIG_NET_CLS_ACT
  91         if (qdisc == NULL) {
  92
  93                 if (ret == NET_XMIT_BYPASS)
  94                         sch->qstats.drops++;
  95                 kfree_skb(skb);
  96                 return ret;
  97         }
  98 #endif
  99
 100         if ((ret = qdisc->enqueue(skb, qdisc)) == NET_XMIT_SUCCESS) {
 101                 sch->bstats.bytes += skb->len;
 102                 sch->bstats.packets++;
 103                 sch->q.qlen++;
 104                 return NET_XMIT_SUCCESS;
 105         }
 106         sch->qstats.drops++;
 107         return ret;
 108 }
 109
 110
 111 static int
 112 prio_requeue(struct sk_buff *skb, struct Qdisc* sch)
 113 {
 114         struct Qdisc *qdisc;
 115         int ret;
 116
 117         qdisc = prio_classify(skb, sch, &ret);
 118 #ifdef CONFIG_NET_CLS_ACT
 119         if (qdisc == NULL) {
 120                 if (ret == NET_XMIT_BYPASS)
 121                         sch->qstats.drops++;
 122                 kfree_skb(skb);
 123                 return ret;
 124         }
 125 #endif
 126
 127         if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) {
 128                 sch->q.qlen++;
 129                 sch->qstats.requeues++;
 130                 return 0;
 131         }
 132         sch->qstats.drops++;
 133         return NET_XMIT_DROP;
 134 }
 135
 136
 137 static struct sk_buff *
 138 prio_dequeue(struct Qdisc* sch)
 139 {
 140         struct sk_buff *skb;
 141         struct prio_sched_data *q = qdisc_priv(sch);
 142         int prio;
 143         struct Qdisc *qdisc;
 144
 145         for (prio = 0; prio < q->bands; prio++) {
 146                 qdisc = q->queues[prio];
 147                 skb = qdisc->dequeue(qdisc);
 148                 if (skb) {
 149                         sch->q.qlen--;
 150                         return skb;
 151                 }
 152         }
 153         return NULL;
 154
 155 }
 156
 157 static unsigned int prio_drop(struct Qdisc* sch)
 158 {
 159         struct prio_sched_data *q = qdisc_priv(sch);
 160         int prio;
 161         unsigned int len;
 162         struct Qdisc *qdisc;
 163
 164         for (prio = q->bands-1; prio >= 0; prio--) {
 165                 qdisc = q->queues[prio];
 166                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 167                         sch->q.qlen--;
 168                         return len;
 169                 }
 170         }
 171         return 0;
 172 }
 173
 174
 175 static void
 176 prio_reset(struct Qdisc* sch)
 177 {
 178         int prio;
 179         struct prio_sched_data *q = qdisc_priv(sch);
 180
 181         for (prio=0; prio<q->bands; prio++)
 182                 qdisc_reset(q->queues[prio]);
 183         sch->q.qlen = 0;
 184 }
 185
 186 static void
 187 prio_destroy(struct Qdisc* sch)
 188 {
 189         int prio;
 190         struct prio_sched_data *q = qdisc_priv(sch);
 191         struct tcf_proto *tp;
 192
 193         while ((tp = q->filter_list) != NULL) {
 194                 q->filter_list = tp->next;
 195                 tcf_destroy(tp);
 196         }
 197
 198         for (prio=0; prio<q->bands; prio++)
 199                 qdisc_destroy(q->queues[prio]);
 200 }
 201
 202 static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
 203 {
 204         struct prio_sched_data *q = qdisc_priv(sch);
 205         struct tc_prio_qopt *qopt = RTA_DATA(opt);
 206         int i;
 207
 208         if (opt->rta_len < RTA_LENGTH(sizeof(*qopt)))
 209                 return -EINVAL;
 210         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 211                 return -EINVAL;
 212
 213         for (i=0; i<=TC_PRIO_MAX; i++) {
 214                 if (qopt->priomap[i] >= qopt->bands)
 215                         return -EINVAL;
 216         }
 217
 218         sch_tree_lock(sch);
 219         q->bands = qopt->bands;
 220         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 221
 222         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
 223                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 224                 if (child != &noop_qdisc) {
 225                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 226                         qdisc_destroy(child);
 227                 }
 228         }
 229         sch_tree_unlock(sch);
 230
 231         for (i=0; i<q->bands; i++) {
 232                 if (q->queues[i] == &noop_qdisc) {
 233                         struct Qdisc *child;
 234                         child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
 235                                                   TC_H_MAKE(sch->handle, i + 1));
 236                         if (child) {
 237                                 sch_tree_lock(sch);
 238                                 child = xchg(&q->queues[i], child);
 239
 240                                 if (child != &noop_qdisc) {
 241                                         qdisc_tree_decrease_qlen(child,
 242                                                                  child->q.qlen);
 243                                         qdisc_destroy(child);
 244                                 }
 245                                 sch_tree_unlock(sch);
 246                         }
 247                 }
 248         }
 249         return 0;
 250 }
 251
 252 static int prio_init(struct Qdisc *sch, struct rtattr *opt)
 253 {
 254         struct prio_sched_data *q = qdisc_priv(sch);
 255         int i;
 256
 257         for (i=0; i<TCQ_PRIO_BANDS; i++)
 258                 q->queues[i] = &noop_qdisc;
 259
 260         if (opt == NULL) {
 261                 return -EINVAL;
 262         } else {
 263                 int err;
 264
 265                 if ((err= prio_tune(sch, opt)) != 0)
 266                         return err;
 267         }
 268         return 0;
 269 }
 270
 271 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 272 {
 273         struct prio_sched_data *q = qdisc_priv(sch);
 274         unsigned char    *b = skb->tail;
 275         struct tc_prio_qopt opt;
 276
 277         opt.bands = q->bands;
 278         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
 279         RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 280         return skb->len;
 281
 282 rtattr_failure:
 283         skb_trim(skb, b - skb->data);
 284         return -1;
 285 }
 286
 287 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 288                       struct Qdisc **old)
 289 {
 290         struct prio_sched_data *q = qdisc_priv(sch);
 291         unsigned long band = arg - 1;
 292
 293         if (band >= q->bands)
 294                 return -EINVAL;
 295
 296         if (new == NULL)
 297                 new = &noop_qdisc;
 298
 299         sch_tree_lock(sch);
 300         *old = q->queues[band];
 301         q->queues[band] = new;
 302         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 303         qdisc_reset(*old);
 304         sch_tree_unlock(sch);
 305
 306         return 0;
 307 }
 308
 309 static struct Qdisc *
 310 prio_leaf(struct Qdisc *sch, unsigned long arg)
 311 {
 312         struct prio_sched_data *q = qdisc_priv(sch);
 313         unsigned long band = arg - 1;
 314
 315         if (band >= q->bands)
 316                 return NULL;
 317
 318         return q->queues[band];
 319 }
 320
 321 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 322 {
 323         struct prio_sched_data *q = qdisc_priv(sch);
 324         unsigned long band = TC_H_MIN(classid);
 325
 326         if (band - 1 >= q->bands)
 327                 return 0;
 328         return band;
 329 }
 330
 331 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 332 {
 333         return prio_get(sch, classid);
 334 }
 335
 336
 337 static void prio_put(struct Qdisc *q, unsigned long cl)
 338 {
 339         return;
 340 }
 341
 342 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct rtattr **tca, unsigned long *arg)
 343 {
 344         unsigned long cl = *arg;
 345         struct prio_sched_data *q = qdisc_priv(sch);
 346
 347         if (cl - 1 > q->bands)
 348                 return -ENOENT;
 349         return 0;
 350 }
 351
 352 static int prio_delete(struct Qdisc *sch, unsigned long cl)
 353 {
 354         struct prio_sched_data *q = qdisc_priv(sch);
 355         if (cl - 1 > q->bands)
 356                 return -ENOENT;
 357         return 0;
 358 }
 359
 360
 361 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 362                            struct tcmsg *tcm)
 363 {
 364         struct prio_sched_data *q = qdisc_priv(sch);
 365
 366         if (cl - 1 > q->bands)
 367                 return -ENOENT;
 368         tcm->tcm_handle |= TC_H_MIN(cl);
 369         if (q->queues[cl-1])
 370                 tcm->tcm_info = q->queues[cl-1]->handle;
 371         return 0;
 372 }
 373
 374 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 375                                  struct gnet_dump *d)
 376 {
 377         struct prio_sched_data *q = qdisc_priv(sch);
 378         struct Qdisc *cl_q;
 379
 380         cl_q = q->queues[cl - 1];
 381         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 382             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 383                 return -1;
 384
 385         return 0;
 386 }
 387
 388 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 389 {
 390         struct prio_sched_data *q = qdisc_priv(sch);
 391         int prio;
 392
 393         if (arg->stop)
 394                 return;
 395
 396         for (prio = 0; prio < q->bands; prio++) {
 397                 if (arg->count < arg->skip) {
 398                         arg->count++;
 399                         continue;
 400                 }
 401                 if (arg->fn(sch, prio+1, arg) < 0) {
 402                         arg->stop = 1;
 403                         break;
 404                 }
 405                 arg->count++;
 406         }
 407 }
 408
 409 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
 410 {
 411         struct prio_sched_data *q = qdisc_priv(sch);
 412
 413         if (cl)
 414                 return NULL;
 415         return &q->filter_list;
 416 }
 417
 418 static struct Qdisc_class_ops prio_class_ops = {
 419         .graft          =       prio_graft,
 420         .leaf           =       prio_leaf,
 421         .get            =       prio_get,
 422         .put            =       prio_put,
 423         .change         =       prio_change,
 424         .delete         =       prio_delete,
 425         .walk           =       prio_walk,
 426         .tcf_chain      =       prio_find_tcf,
 427         .bind_tcf       =       prio_bind,
 428         .unbind_tcf     =       prio_put,
 429         .dump           =       prio_dump_class,
 430         .dump_stats     =       prio_dump_class_stats,
 431 };
 432
 433 static struct Qdisc_ops prio_qdisc_ops = {
 434         .next           =       NULL,
 435         .cl_ops         =       &prio_class_ops,
 436         .id             =       "prio",
 437         .priv_size      =       sizeof(struct prio_sched_data),
 438         .enqueue        =       prio_enqueue,
 439         .dequeue        =       prio_dequeue,
 440         .requeue        =       prio_requeue,
 441         .drop           =       prio_drop,
 442         .init           =       prio_init,
 443         .reset          =       prio_reset,
 444         .destroy        =       prio_destroy,
 445         .change         =       prio_tune,
 446         .dump           =       prio_dump,
 447         .owner          =       THIS_MODULE,
 448 };
 449
 450 static int __init prio_module_init(void)
 451 {
 452         return register_qdisc(&prio_qdisc_ops);
 453 }
 454
 455 static void __exit prio_module_exit(void)
 456 {
 457         unregister_qdisc(&prio_qdisc_ops);
 458 }
 459
 460 module_init(prio_module_init)
 461 module_exit(prio_module_exit)
 462
 463 MODULE_LICENSE("GPL");