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/netlink.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
 193         tcf_destroy_chain(q->filter_list);
 194         for (prio=0; prio<q->bands; prio++)
 195                 qdisc_destroy(q->queues[prio]);
 196 }
 197
 198 static int prio_tune(struct Qdisc *sch, struct rtattr *opt)
 199 {
 200         struct prio_sched_data *q = qdisc_priv(sch);
 201         struct tc_prio_qopt *qopt = RTA_DATA(opt);
 202         int i;
 203
 204         if (opt->rta_len < RTA_LENGTH(sizeof(*qopt)))
 205                 return -EINVAL;
 206         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 207                 return -EINVAL;
 208
 209         for (i=0; i<=TC_PRIO_MAX; i++) {
 210                 if (qopt->priomap[i] >= qopt->bands)
 211                         return -EINVAL;
 212         }
 213
 214         sch_tree_lock(sch);
 215         q->bands = qopt->bands;
 216         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 217
 218         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
 219                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 220                 if (child != &noop_qdisc) {
 221                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 222                         qdisc_destroy(child);
 223                 }
 224         }
 225         sch_tree_unlock(sch);
 226
 227         for (i=0; i<q->bands; i++) {
 228                 if (q->queues[i] == &noop_qdisc) {
 229                         struct Qdisc *child;
 230                         child = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
 231                                                   TC_H_MAKE(sch->handle, i + 1));
 232                         if (child) {
 233                                 sch_tree_lock(sch);
 234                                 child = xchg(&q->queues[i], child);
 235
 236                                 if (child != &noop_qdisc) {
 237                                         qdisc_tree_decrease_qlen(child,
 238                                                                  child->q.qlen);
 239                                         qdisc_destroy(child);
 240                                 }
 241                                 sch_tree_unlock(sch);
 242                         }
 243                 }
 244         }
 245         return 0;
 246 }
 247
 248 static int prio_init(struct Qdisc *sch, struct rtattr *opt)
 249 {
 250         struct prio_sched_data *q = qdisc_priv(sch);
 251         int i;
 252
 253         for (i=0; i<TCQ_PRIO_BANDS; i++)
 254                 q->queues[i] = &noop_qdisc;
 255
 256         if (opt == NULL) {
 257                 return -EINVAL;
 258         } else {
 259                 int err;
 260
 261                 if ((err= prio_tune(sch, opt)) != 0)
 262                         return err;
 263         }
 264         return 0;
 265 }
 266
 267 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 268 {
 269         struct prio_sched_data *q = qdisc_priv(sch);
 270         unsigned char *b = skb_tail_pointer(skb);
 271         struct tc_prio_qopt opt;
 272
 273         opt.bands = q->bands;
 274         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
 275         RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 276         return skb->len;
 277
 278 rtattr_failure:
 279         nlmsg_trim(skb, b);
 280         return -1;
 281 }
 282
 283 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 284                       struct Qdisc **old)
 285 {
 286         struct prio_sched_data *q = qdisc_priv(sch);
 287         unsigned long band = arg - 1;
 288
 289         if (band >= q->bands)
 290                 return -EINVAL;
 291
 292         if (new == NULL)
 293                 new = &noop_qdisc;
 294
 295         sch_tree_lock(sch);
 296         *old = q->queues[band];
 297         q->queues[band] = new;
 298         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 299         qdisc_reset(*old);
 300         sch_tree_unlock(sch);
 301
 302         return 0;
 303 }
 304
 305 static struct Qdisc *
 306 prio_leaf(struct Qdisc *sch, unsigned long arg)
 307 {
 308         struct prio_sched_data *q = qdisc_priv(sch);
 309         unsigned long band = arg - 1;
 310
 311         if (band >= q->bands)
 312                 return NULL;
 313
 314         return q->queues[band];
 315 }
 316
 317 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 318 {
 319         struct prio_sched_data *q = qdisc_priv(sch);
 320         unsigned long band = TC_H_MIN(classid);
 321
 322         if (band - 1 >= q->bands)
 323                 return 0;
 324         return band;
 325 }
 326
 327 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 328 {
 329         return prio_get(sch, classid);
 330 }
 331
 332
 333 static void prio_put(struct Qdisc *q, unsigned long cl)
 334 {
 335         return;
 336 }
 337
 338 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct rtattr **tca, unsigned long *arg)
 339 {
 340         unsigned long cl = *arg;
 341         struct prio_sched_data *q = qdisc_priv(sch);
 342
 343         if (cl - 1 > q->bands)
 344                 return -ENOENT;
 345         return 0;
 346 }
 347
 348 static int prio_delete(struct Qdisc *sch, unsigned long cl)
 349 {
 350         struct prio_sched_data *q = qdisc_priv(sch);
 351         if (cl - 1 > q->bands)
 352                 return -ENOENT;
 353         return 0;
 354 }
 355
 356
 357 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 358                            struct tcmsg *tcm)
 359 {
 360         struct prio_sched_data *q = qdisc_priv(sch);
 361
 362         if (cl - 1 > q->bands)
 363                 return -ENOENT;
 364         tcm->tcm_handle |= TC_H_MIN(cl);
 365         if (q->queues[cl-1])
 366                 tcm->tcm_info = q->queues[cl-1]->handle;
 367         return 0;
 368 }
 369
 370 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 371                                  struct gnet_dump *d)
 372 {
 373         struct prio_sched_data *q = qdisc_priv(sch);
 374         struct Qdisc *cl_q;
 375
 376         cl_q = q->queues[cl - 1];
 377         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 378             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 379                 return -1;
 380
 381         return 0;
 382 }
 383
 384 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 385 {
 386         struct prio_sched_data *q = qdisc_priv(sch);
 387         int prio;
 388
 389         if (arg->stop)
 390                 return;
 391
 392         for (prio = 0; prio < q->bands; prio++) {
 393                 if (arg->count < arg->skip) {
 394                         arg->count++;
 395                         continue;
 396                 }
 397                 if (arg->fn(sch, prio+1, arg) < 0) {
 398                         arg->stop = 1;
 399                         break;
 400                 }
 401                 arg->count++;
 402         }
 403 }
 404
 405 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
 406 {
 407         struct prio_sched_data *q = qdisc_priv(sch);
 408
 409         if (cl)
 410                 return NULL;
 411         return &q->filter_list;
 412 }
 413
 414 static struct Qdisc_class_ops prio_class_ops = {
 415         .graft          =       prio_graft,
 416         .leaf           =       prio_leaf,
 417         .get            =       prio_get,
 418         .put            =       prio_put,
 419         .change         =       prio_change,
 420         .delete         =       prio_delete,
 421         .walk           =       prio_walk,
 422         .tcf_chain      =       prio_find_tcf,
 423         .bind_tcf       =       prio_bind,
 424         .unbind_tcf     =       prio_put,
 425         .dump           =       prio_dump_class,
 426         .dump_stats     =       prio_dump_class_stats,
 427 };
 428
 429 static struct Qdisc_ops prio_qdisc_ops = {
 430         .next           =       NULL,
 431         .cl_ops         =       &prio_class_ops,
 432         .id             =       "prio",
 433         .priv_size      =       sizeof(struct prio_sched_data),
 434         .enqueue        =       prio_enqueue,
 435         .dequeue        =       prio_dequeue,
 436         .requeue        =       prio_requeue,
 437         .drop           =       prio_drop,
 438         .init           =       prio_init,
 439         .reset          =       prio_reset,
 440         .destroy        =       prio_destroy,
 441         .change         =       prio_tune,
 442         .dump           =       prio_dump,
 443         .owner          =       THIS_MODULE,
 444 };
 445
 446 static int __init prio_module_init(void)
 447 {
 448         return register_qdisc(&prio_qdisc_ops);
 449 }
 450
 451 static void __exit prio_module_exit(void)
 452 {
 453         unregister_qdisc(&prio_qdisc_ops);
 454 }
 455
 456 module_init(prio_module_init)
 457 module_exit(prio_module_exit)
 458
 459 MODULE_LICENSE("GPL");