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