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(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"); 407