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