linux/net/sched/sch_prio.c
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   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
  24struct 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
  33static struct Qdisc *
  34prio_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
  67static int
  68prio_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
  96static struct sk_buff *prio_peek(struct Qdisc *sch)
  97{
  98        struct prio_sched_data *q = qdisc_priv(sch);
  99        int prio;
 100
 101        for (prio = 0; prio < q->bands; prio++) {
 102                struct Qdisc *qdisc = q->queues[prio];
 103                struct sk_buff *skb = qdisc->ops->peek(qdisc);
 104                if (skb)
 105                        return skb;
 106        }
 107        return NULL;
 108}
 109
 110static struct sk_buff *prio_dequeue(struct Qdisc* sch)
 111{
 112        struct prio_sched_data *q = qdisc_priv(sch);
 113        int prio;
 114
 115        for (prio = 0; prio < q->bands; prio++) {
 116                struct Qdisc *qdisc = q->queues[prio];
 117                struct sk_buff *skb = qdisc->dequeue(qdisc);
 118                if (skb) {
 119                        sch->q.qlen--;
 120                        return skb;
 121                }
 122        }
 123        return NULL;
 124
 125}
 126
 127static unsigned int prio_drop(struct Qdisc* sch)
 128{
 129        struct prio_sched_data *q = qdisc_priv(sch);
 130        int prio;
 131        unsigned int len;
 132        struct Qdisc *qdisc;
 133
 134        for (prio = q->bands-1; prio >= 0; prio--) {
 135                qdisc = q->queues[prio];
 136                if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) {
 137                        sch->q.qlen--;
 138                        return len;
 139                }
 140        }
 141        return 0;
 142}
 143
 144
 145static void
 146prio_reset(struct Qdisc* sch)
 147{
 148        int prio;
 149        struct prio_sched_data *q = qdisc_priv(sch);
 150
 151        for (prio=0; prio<q->bands; prio++)
 152                qdisc_reset(q->queues[prio]);
 153        sch->q.qlen = 0;
 154}
 155
 156static void
 157prio_destroy(struct Qdisc* sch)
 158{
 159        int prio;
 160        struct prio_sched_data *q = qdisc_priv(sch);
 161
 162        tcf_destroy_chain(&q->filter_list);
 163        for (prio=0; prio<q->bands; prio++)
 164                qdisc_destroy(q->queues[prio]);
 165}
 166
 167static int prio_tune(struct Qdisc *sch, struct nlattr *opt)
 168{
 169        struct prio_sched_data *q = qdisc_priv(sch);
 170        struct tc_prio_qopt *qopt;
 171        int i;
 172
 173        if (nla_len(opt) < sizeof(*qopt))
 174                return -EINVAL;
 175        qopt = nla_data(opt);
 176
 177        if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2)
 178                return -EINVAL;
 179
 180        for (i=0; i<=TC_PRIO_MAX; i++) {
 181                if (qopt->priomap[i] >= qopt->bands)
 182                        return -EINVAL;
 183        }
 184
 185        sch_tree_lock(sch);
 186        q->bands = qopt->bands;
 187        memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
 188
 189        for (i=q->bands; i<TCQ_PRIO_BANDS; i++) {
 190                struct Qdisc *child = q->queues[i];
 191                q->queues[i] = &noop_qdisc;
 192                if (child != &noop_qdisc) {
 193                        qdisc_tree_decrease_qlen(child, child->q.qlen);
 194                        qdisc_destroy(child);
 195                }
 196        }
 197        sch_tree_unlock(sch);
 198
 199        for (i=0; i<q->bands; i++) {
 200                if (q->queues[i] == &noop_qdisc) {
 201                        struct Qdisc *child, *old;
 202                        child = qdisc_create_dflt(qdisc_dev(sch), 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
 222static 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
 241static 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
 254nla_put_failure:
 255        nlmsg_trim(skb, b);
 256        return -1;
 257}
 258
 259static 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 (band >= q->bands)
 266                return -EINVAL;
 267
 268        if (new == NULL)
 269                new = &noop_qdisc;
 270
 271        sch_tree_lock(sch);
 272        *old = q->queues[band];
 273        q->queues[band] = new;
 274        qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
 275        qdisc_reset(*old);
 276        sch_tree_unlock(sch);
 277
 278        return 0;
 279}
 280
 281static struct Qdisc *
 282prio_leaf(struct Qdisc *sch, unsigned long arg)
 283{
 284        struct prio_sched_data *q = qdisc_priv(sch);
 285        unsigned long band = arg - 1;
 286
 287        if (band >= q->bands)
 288                return NULL;
 289
 290        return q->queues[band];
 291}
 292
 293static unsigned long prio_get(struct Qdisc *sch, u32 classid)
 294{
 295        struct prio_sched_data *q = qdisc_priv(sch);
 296        unsigned long band = TC_H_MIN(classid);
 297
 298        if (band - 1 >= q->bands)
 299                return 0;
 300        return band;
 301}
 302
 303static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
 304{
 305        return prio_get(sch, classid);
 306}
 307
 308
 309static void prio_put(struct Qdisc *q, unsigned long cl)
 310{
 311        return;
 312}
 313
 314static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg)
 315{
 316        unsigned long cl = *arg;
 317        struct prio_sched_data *q = qdisc_priv(sch);
 318
 319        if (cl - 1 > q->bands)
 320                return -ENOENT;
 321        return 0;
 322}
 323
 324static int prio_delete(struct Qdisc *sch, unsigned long cl)
 325{
 326        struct prio_sched_data *q = qdisc_priv(sch);
 327        if (cl - 1 > q->bands)
 328                return -ENOENT;
 329        return 0;
 330}
 331
 332
 333static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
 334                           struct tcmsg *tcm)
 335{
 336        struct prio_sched_data *q = qdisc_priv(sch);
 337
 338        if (cl - 1 > q->bands)
 339                return -ENOENT;
 340        tcm->tcm_handle |= TC_H_MIN(cl);
 341        if (q->queues[cl-1])
 342                tcm->tcm_info = q->queues[cl-1]->handle;
 343        return 0;
 344}
 345
 346static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
 347                                 struct gnet_dump *d)
 348{
 349        struct prio_sched_data *q = qdisc_priv(sch);
 350        struct Qdisc *cl_q;
 351
 352        cl_q = q->queues[cl - 1];
 353        if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 354            gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 355                return -1;
 356
 357        return 0;
 358}
 359
 360static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
 361{
 362        struct prio_sched_data *q = qdisc_priv(sch);
 363        int prio;
 364
 365        if (arg->stop)
 366                return;
 367
 368        for (prio = 0; prio < q->bands; prio++) {
 369                if (arg->count < arg->skip) {
 370                        arg->count++;
 371                        continue;
 372                }
 373                if (arg->fn(sch, prio+1, arg) < 0) {
 374                        arg->stop = 1;
 375                        break;
 376                }
 377                arg->count++;
 378        }
 379}
 380
 381static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl)
 382{
 383        struct prio_sched_data *q = qdisc_priv(sch);
 384
 385        if (cl)
 386                return NULL;
 387        return &q->filter_list;
 388}
 389
 390static const struct Qdisc_class_ops prio_class_ops = {
 391        .graft          =       prio_graft,
 392        .leaf           =       prio_leaf,
 393        .get            =       prio_get,
 394        .put            =       prio_put,
 395        .change         =       prio_change,
 396        .delete         =       prio_delete,
 397        .walk           =       prio_walk,
 398        .tcf_chain      =       prio_find_tcf,
 399        .bind_tcf       =       prio_bind,
 400        .unbind_tcf     =       prio_put,
 401        .dump           =       prio_dump_class,
 402        .dump_stats     =       prio_dump_class_stats,
 403};
 404
 405static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
 406        .next           =       NULL,
 407        .cl_ops         =       &prio_class_ops,
 408        .id             =       "prio",
 409        .priv_size      =       sizeof(struct prio_sched_data),
 410        .enqueue        =       prio_enqueue,
 411        .dequeue        =       prio_dequeue,
 412        .peek           =       prio_peek,
 413        .drop           =       prio_drop,
 414        .init           =       prio_init,
 415        .reset          =       prio_reset,
 416        .destroy        =       prio_destroy,
 417        .change         =       prio_tune,
 418        .dump           =       prio_dump,
 419        .owner          =       THIS_MODULE,
 420};
 421
 422static int __init prio_module_init(void)
 423{
 424        return register_qdisc(&prio_qdisc_ops);
 425}
 426
 427static void __exit prio_module_exit(void)
 428{
 429        unregister_qdisc(&prio_qdisc_ops);
 430}
 431
 432module_init(prio_module_init)
 433module_exit(prio_module_exit)
 434
 435MODULE_LICENSE("GPL");
 436