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_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 0;
 117         }
 118         if (net_xmit_drop_count(ret))
 119                 sch->qstats.drops++;
 120         return NET_XMIT_DROP;
 121 }
 122
 123
 124 static struct sk_buff *prio_dequeue(struct Qdisc* sch)
 125 {
 126         struct prio_sched_data *q = qdisc_priv(sch);
 127         int prio;
 128
 129         for (prio = 0; prio < q->bands; prio++) {
 130                 struct Qdisc *qdisc = q->queues[prio];
 131                 struct sk_buff *skb = qdisc->dequeue(qdisc);
 132                 if (skb) {
 133                         sch->q.qlen--;
 134                         return skb;
 135                 }
 136         }
 137         return NULL;
 138
 139 }
 140
 141 static unsigned int prio_drop(struct Qdisc* sch)
 142 {
 143         struct prio_sched_data *q = qdisc_priv(sch);
 144         int prio;
 145         unsigned int len;
 146         struct Qdisc *qdisc;
 147
 148         for (prio = q->bands-1; prio >= 0; prio--) {
 149                 qdisc = q->queues[prio];
 150                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 151                         sch->q.qlen--;
 152                         return len;
 153                 }
 154         }
 155         return 0;
 156 }
 157
 158
 159 static void
 160 prio_reset(struct Qdisc* sch)
 161 {
 162         int prio;
 163         struct prio_sched_data *q = qdisc_priv(sch);
 164
 165         for (prio=0; prio<q->bands; prio++)
 166                 qdisc_reset(q->queues[prio]);
 167         sch->q.qlen = 0;
 168 }
 169
 170 static void
 171 prio_destroy(struct Qdisc* sch)
 172 {
 173         int prio;
 174         struct prio_sched_data *q = qdisc_priv(sch);
 175
 176         tcf_destroy_chain(&q->filter_list);
 177         for (prio=0; prio<q->bands; prio++)
 178                 qdisc_destroy(q->queues[prio]);
 179 }
 180
 181 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 182 {
 183         struct prio_sched_data *q = qdisc_priv(sch);
 184         struct tc_prio_qopt *qopt;
 185         int i;
 186
 187         if (nla_len(opt) < sizeof(*qopt))
 188                 return -EINVAL;
 189         qopt = nla_data(opt);
 190
 191         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 192                 return -EINVAL;
 193
 194         for (i=0; i<=TC_PRIO_MAX; i++) {
 195                 if (qopt->priomap[i] >= qopt->bands)
 196                         return -EINVAL;
 197         }
 198
 199         sch_tree_lock(sch);
 200         q->bands = qopt->bands;
 201         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 202
 203         for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
 204                 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc);
 205                 if (child != &noop_qdisc) {
 206                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 207                         qdisc_destroy(child);
 208                 }
 209         }
 210         sch_tree_unlock(sch);
 211
 212         for (i=0; i<q->bands; i++) {
 213                 if (q->queues[i] == &noop_qdisc) {
 214                         struct Qdisc *child;
 215                         child = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
 216                                                   &pfifo_qdisc_ops,
 217                                                   TC_H_MAKE(sch->handle, i + 1));
 218                         if (child) {
 219                                 sch_tree_lock(sch);
 220                                 child = xchg(&q->queues[i], child);
 221
 222                                 if (child != &noop_qdisc) {
 223                                         qdisc_tree_decrease_qlen(child,
 224                                                                  child->q.qlen);
 225                                         qdisc_destroy(child);
 226                                 }
 227                                 sch_tree_unlock(sch);
 228                         }
 229                 }
 230         }
 231         return 0;
 232 }
 233
 234 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
 235 {
 236         struct prio_sched_data *q = qdisc_priv(sch);
 237         int i;
 238
 239         for (i=0; i<TCQ_PRIO_BANDS; i++)
 240                 q->queues[i] = &noop_qdisc;
 241
 242         if (opt == NULL) {
 243                 return -EINVAL;
 244         } else {
 245                 int err;
 246
 247                 if ((err= prio_tune(sch, opt)) != 0)
 248                         return err;
 249         }
 250         return 0;
 251 }
 252
 253 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 254 {
 255         struct prio_sched_data *q = qdisc_priv(sch);
 256         unsigned char *b = skb_tail_pointer(skb);
 257         struct nlattr *nest;
 258         struct tc_prio_qopt opt;
 259
 260         opt.bands = q->bands;
 261         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1);
 262
 263         nest = nla_nest_compat_start(skb, TCA_OPTIONS, sizeof(opt), &opt);
 264         if (nest == NULL)
 265                 goto nla_put_failure;
 266         nla_nest_compat_end(skb, nest);
 267
 268         return skb->len;
 269
 270 nla_put_failure:
 271         nlmsg_trim(skb, b);
 272         return -1;
 273 }
 274
 275 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 276                       struct Qdisc **old)
 277 {
 278         struct prio_sched_data *q = qdisc_priv(sch);
 279         unsigned long band = arg - 1;
 280
 281         if (band >= q->bands)
 282                 return -EINVAL;
 283
 284         if (new == NULL)
 285                 new = &noop_qdisc;
 286
 287         sch_tree_lock(sch);
 288         *old = q->queues[band];
 289         q->queues[band] = new;
 290         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 291         qdisc_reset(*old);
 292         sch_tree_unlock(sch);
 293
 294         return 0;
 295 }
 296
 297 static struct Qdisc *
 298 prio_leaf(struct Qdisc *sch, unsigned long arg)
 299 {
 300         struct prio_sched_data *q = qdisc_priv(sch);
 301         unsigned long band = arg - 1;
 302
 303         if (band >= q->bands)
 304                 return NULL;
 305
 306         return q->queues[band];
 307 }
 308
 309 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 310 {
 311         struct prio_sched_data *q = qdisc_priv(sch);
 312         unsigned long band = TC_H_MIN(classid);
 313
 314         if (band - 1 >= q->bands)
 315                 return 0;
 316         return band;
 317 }
 318
 319 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 320 {
 321         return prio_get(sch, classid);
 322 }
 323
 324
 325 static void prio_put(struct Qdisc *q, unsigned long cl)
 326 {
 327         return;
 328 }
 329
 330 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg)
 331 {
 332         unsigned long cl = *arg;
 333         struct prio_sched_data *q = qdisc_priv(sch);
 334
 335         if (cl - 1 > q->bands)
 336                 return -ENOENT;
 337         return 0;
 338 }
 339
 340 static int prio_delete(struct Qdisc *sch, unsigned long cl)
 341 {
 342         struct prio_sched_data *q = qdisc_priv(sch);
 343         if (cl - 1 > q->bands)
 344                 return -ENOENT;
 345         return 0;
 346 }
 347
 348
 349 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 350                            struct tcmsg *tcm)
 351 {
 352         struct prio_sched_data *q = qdisc_priv(sch);
 353
 354         if (cl - 1 > q->bands)
 355                 return -ENOENT;
 356         tcm->tcm_handle |= TC_H_MIN(cl);
 357         if (q->queues[cl-1])
 358                 tcm->tcm_info = q->queues[cl-1]->handle;
 359         return 0;
 360 }
 361
 362 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 363                                  struct gnet_dump *d)
 364 {
 365         struct prio_sched_data *q = qdisc_priv(sch);
 366         struct Qdisc *cl_q;
 367
 368         cl_q = q->queues[cl - 1];
 369         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 370             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 371                 return -1;
 372
 373         return 0;
 374 }
 375
 376 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 377 {
 378         struct prio_sched_data *q = qdisc_priv(sch);
 379         int prio;
 380
 381         if (arg->stop)
 382                 return;
 383
 384         for (prio = 0; prio < q->bands; prio++) {
 385                 if (arg->count < arg->skip) {
 386                         arg->count++;
 387                         continue;
 388                 }
 389                 if (arg->fn(sch, prio+1, arg) < 0) {
 390                         arg->stop = 1;
 391                         break;
 392                 }
 393                 arg->count++;
 394         }
 395 }
 396
 397 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
 398 {
 399         struct prio_sched_data *q = qdisc_priv(sch);
 400
 401         if (cl)
 402                 return NULL;
 403         return &q->filter_list;
 404 }
 405
 406 static const struct Qdisc_class_ops prio_class_ops = {
 407         .graft          =       prio_graft,
 408         .leaf           =       prio_leaf,
 409         .get            =       prio_get,
 410         .put            =       prio_put,
 411         .change         =       prio_change,
 412         .delete         =       prio_delete,
 413         .walk           =       prio_walk,
 414         .tcf_chain      =       prio_find_tcf,
 415         .bind_tcf       =       prio_bind,
 416         .unbind_tcf     =       prio_put,
 417         .dump           =       prio_dump_class,
 418         .dump_stats     =       prio_dump_class_stats,
 419 };
 420
 421 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 422         .next           =       NULL,
 423         .cl_ops         =       &prio_class_ops,
 424         .id             =       "prio",
 425         .priv_size      =       sizeof(struct prio_sched_data),
 426         .enqueue        =       prio_enqueue,
 427         .dequeue        =       prio_dequeue,
 428         .requeue        =       prio_requeue,
 429         .drop           =       prio_drop,
 430         .init           =       prio_init,
 431         .reset          =       prio_reset,
 432         .destroy        =       prio_destroy,
 433         .change         =       prio_tune,
 434         .dump           =       prio_dump,
 435         .owner          =       THIS_MODULE,
 436 };
 437
 438 static int __init prio_module_init(void)
 439 {
 440         return register_qdisc(&prio_qdisc_ops);
 441 }
 442
 443 static void __exit prio_module_exit(void)
 444 {
 445         unregister_qdisc(&prio_qdisc_ops);
 446 }
 447
 448 module_init(prio_module_init)
 449 module_exit(prio_module_exit)
 450
 451 MODULE_LICENSE("GPL");