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/slab.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/errno.h>
  20 #include <linux/skbuff.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23
  24
  25 struct prio_sched_data {
  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->q.qlen++;
  87                 return NET_XMIT_SUCCESS;
  88         }
  89         if (net_xmit_drop_count(ret))
  90                 sch->qstats.drops++;
  91         return ret;
  92 }
  93
  94 static struct sk_buff *prio_peek(struct Qdisc *sch)
  95 {
  96         struct prio_sched_data *q = qdisc_priv(sch);
  97         int prio;
  98
  99         for (prio = 0; prio < q->bands; prio++) {
 100                 struct Qdisc *qdisc = q->queues[prio];
 101                 struct sk_buff *skb = qdisc->ops->peek(qdisc);
 102                 if (skb)
 103                         return skb;
 104         }
 105         return NULL;
 106 }
 107
 108 static struct sk_buff *prio_dequeue(struct Qdisc *sch)
 109 {
 110         struct prio_sched_data *q = qdisc_priv(sch);
 111         int prio;
 112
 113         for (prio = 0; prio < q->bands; prio++) {
 114                 struct Qdisc *qdisc = q->queues[prio];
 115                 struct sk_buff *skb = qdisc_dequeue_peeked(qdisc);
 116                 if (skb) {
 117                         qdisc_bstats_update(sch, skb);
 118                         sch->q.qlen--;
 119                         return skb;
 120                 }
 121         }
 122         return NULL;
 123
 124 }
 125
 126 static unsigned int prio_drop(struct Qdisc *sch)
 127 {
 128         struct prio_sched_data *q = qdisc_priv(sch);
 129         int prio;
 130         unsigned int len;
 131         struct Qdisc *qdisc;
 132
 133         for (prio = q->bands-1; prio >= 0; prio--) {
 134                 qdisc = q->queues[prio];
 135                 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 136                         sch->q.qlen--;
 137                         return len;
 138                 }
 139         }
 140         return 0;
 141 }
 142
 143
 144 static void
 145 prio_reset(struct Qdisc *sch)
 146 {
 147         int prio;
 148         struct prio_sched_data *q = qdisc_priv(sch);
 149
 150         for (prio = 0; prio < q->bands; prio++)
 151                 qdisc_reset(q->queues[prio]);
 152         sch->q.qlen = 0;
 153 }
 154
 155 static void
 156 prio_destroy(struct Qdisc *sch)
 157 {
 158         int prio;
 159         struct prio_sched_data *q = qdisc_priv(sch);
 160
 161         tcf_destroy_chain(&q->filter_list);
 162         for (prio = 0; prio < q->bands; prio++)
 163                 qdisc_destroy(q->queues[prio]);
 164 }
 165
 166 static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 167 {
 168         struct prio_sched_data *q = qdisc_priv(sch);
 169         struct tc_prio_qopt *qopt;
 170         int i;
 171
 172         if (nla_len(opt) < sizeof(*qopt))
 173                 return -EINVAL;
 174         qopt = nla_data(opt);
 175
 176         if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 177                 return -EINVAL;
 178
 179         for (i = 0; i <= TC_PRIO_MAX; i++) {
 180                 if (qopt->priomap[i] >= qopt->bands)
 181                         return -EINVAL;
 182         }
 183
 184         sch_tree_lock(sch);
 185         q->bands = qopt->bands;
 186         memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 187
 188         for (i = q->bands; i < TCQ_PRIO_BANDS; i++) {
 189                 struct Qdisc *child = q->queues[i];
 190                 q->queues[i] = &noop_qdisc;
 191                 if (child != &noop_qdisc) {
 192                         qdisc_tree_decrease_qlen(child, child->q.qlen);
 193                         qdisc_destroy(child);
 194                 }
 195         }
 196         sch_tree_unlock(sch);
 197
 198         for (i = 0; i < q->bands; i++) {
 199                 if (q->queues[i] == &noop_qdisc) {
 200                         struct Qdisc *child, *old;
 201
 202                         child = qdisc_create_dflt(sch->dev_queue,
 203                                                   &pfifo_qdisc_ops,
 204                                                   TC_H_MAKE(sch->handle, i + 1));
 205                         if (child) {
 206                                 sch_tree_lock(sch);
 207                                 old = q->queues[i];
 208                                 q->queues[i] = child;
 209
 210                                 if (old != &noop_qdisc) {
 211                                         qdisc_tree_decrease_qlen(old,
 212                                                                  old->q.qlen);
 213                                         qdisc_destroy(old);
 214                                 }
 215                                 sch_tree_unlock(sch);
 216                         }
 217                 }
 218         }
 219         return 0;
 220 }
 221
 222 static int prio_init(struct Qdisc *sch, struct nlattr *opt)
 223 {
 224         struct prio_sched_data *q = qdisc_priv(sch);
 225         int i;
 226
 227         for (i = 0; i < TCQ_PRIO_BANDS; i++)
 228                 q->queues[i] = &noop_qdisc;
 229
 230         if (opt == NULL) {
 231                 return -EINVAL;
 232         } else {
 233                 int err;
 234
 235                 if ((err = prio_tune(sch, opt)) != 0)
 236                         return err;
 237         }
 238         return 0;
 239 }
 240
 241 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
 242 {
 243         struct prio_sched_data *q = qdisc_priv(sch);
 244         unsigned char *b = skb_tail_pointer(skb);
 245         struct tc_prio_qopt opt;
 246
 247         opt.bands = q->bands;
 248         memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
 249
 250         NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
 251
 252         return skb->len;
 253
 254 nla_put_failure:
 255         nlmsg_trim(skb, b);
 256         return -1;
 257 }
 258
 259 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
 260                       struct Qdisc **old)
 261 {
 262         struct prio_sched_data *q = qdisc_priv(sch);
 263         unsigned long band = arg - 1;
 264
 265         if (new == NULL)
 266                 new = &noop_qdisc;
 267
 268         sch_tree_lock(sch);
 269         *old = q->queues[band];
 270         q->queues[band] = new;
 271         qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 272         qdisc_reset(*old);
 273         sch_tree_unlock(sch);
 274
 275         return 0;
 276 }
 277
 278 static struct Qdisc *
 279 prio_leaf(struct Qdisc *sch, unsigned long arg)
 280 {
 281         struct prio_sched_data *q = qdisc_priv(sch);
 282         unsigned long band = arg - 1;
 283
 284         return q->queues[band];
 285 }
 286
 287 static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 288 {
 289         struct prio_sched_data *q = qdisc_priv(sch);
 290         unsigned long band = TC_H_MIN(classid);
 291
 292         if (band - 1 >= q->bands)
 293                 return 0;
 294         return band;
 295 }
 296
 297 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 298 {
 299         return prio_get(sch, classid);
 300 }
 301
 302
 303 static void prio_put(struct Qdisc *q, unsigned long cl)
 304 {
 305 }
 306
 307 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 308                            struct tcmsg *tcm)
 309 {
 310         struct prio_sched_data *q = qdisc_priv(sch);
 311
 312         tcm->tcm_handle |= TC_H_MIN(cl);
 313         tcm->tcm_info = q->queues[cl-1]->handle;
 314         return 0;
 315 }
 316
 317 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 318                                  struct gnet_dump *d)
 319 {
 320         struct prio_sched_data *q = qdisc_priv(sch);
 321         struct Qdisc *cl_q;
 322
 323         cl_q = q->queues[cl - 1];
 324         cl_q->qstats.qlen = cl_q->q.qlen;
 325         if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 326             gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 327                 return -1;
 328
 329         return 0;
 330 }
 331
 332 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 333 {
 334         struct prio_sched_data *q = qdisc_priv(sch);
 335         int prio;
 336
 337         if (arg->stop)
 338                 return;
 339
 340         for (prio = 0; prio < q->bands; prio++) {
 341                 if (arg->count < arg->skip) {
 342                         arg->count++;
 343                         continue;
 344                 }
 345                 if (arg->fn(sch, prio + 1, arg) < 0) {
 346                         arg->stop = 1;
 347                         break;
 348                 }
 349                 arg->count++;
 350         }
 351 }
 352
 353 static struct tcf_proto **prio_find_tcf(struct Qdisc *sch, unsigned long cl)
 354 {
 355         struct prio_sched_data *q = qdisc_priv(sch);
 356
 357         if (cl)
 358                 return NULL;
 359         return &q->filter_list;
 360 }
 361
 362 static const struct Qdisc_class_ops prio_class_ops = {
 363         .graft          =       prio_graft,
 364         .leaf           =       prio_leaf,
 365         .get            =       prio_get,
 366         .put            =       prio_put,
 367         .walk           =       prio_walk,
 368         .tcf_chain      =       prio_find_tcf,
 369         .bind_tcf       =       prio_bind,
 370         .unbind_tcf     =       prio_put,
 371         .dump           =       prio_dump_class,
 372         .dump_stats     =       prio_dump_class_stats,
 373 };
 374
 375 static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 376         .next           =       NULL,
 377         .cl_ops         =       &prio_class_ops,
 378         .id             =       "prio",
 379         .priv_size      =       sizeof(struct prio_sched_data),
 380         .enqueue        =       prio_enqueue,
 381         .dequeue        =       prio_dequeue,
 382         .peek           =       prio_peek,
 383         .drop           =       prio_drop,
 384         .init           =       prio_init,
 385         .reset          =       prio_reset,
 386         .destroy        =       prio_destroy,
 387         .change         =       prio_tune,
 388         .dump           =       prio_dump,
 389         .owner          =       THIS_MODULE,
 390 };
 391
 392 static int __init prio_module_init(void)
 393 {
 394         return register_qdisc(&prio_qdisc_ops);
 395 }
 396
 397 static void __exit prio_module_exit(void)
 398 {
 399         unregister_qdisc(&prio_qdisc_ops);
 400 }
 401
 402 module_init(prio_module_init)
 403 module_exit(prio_module_exit)
 404
 405 MODULE_LICENSE("GPL");