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