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