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11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/init.h>
14#include <linux/errno.h>
15#include <linux/netdevice.h>
16#include <linux/pkt_sched.h>
17#include <net/sch_generic.h>
18#include <net/pkt_sched.h>
19#include <net/pkt_cls.h>
20
21struct drr_class {
22 struct Qdisc_class_common common;
23 unsigned int refcnt;
24 unsigned int filter_cnt;
25
26 struct gnet_stats_basic_packed bstats;
27 struct gnet_stats_queue qstats;
28 struct gnet_stats_rate_est64 rate_est;
29 struct list_head alist;
30 struct Qdisc *qdisc;
31
32 u32 quantum;
33 u32 deficit;
34};
35
36struct drr_sched {
37 struct list_head active;
38 struct tcf_proto __rcu *filter_list;
39 struct Qdisc_class_hash clhash;
40};
41
42static struct drr_class *drr_find_class(struct Qdisc *sch, u32 classid)
43{
44 struct drr_sched *q = qdisc_priv(sch);
45 struct Qdisc_class_common *clc;
46
47 clc = qdisc_class_find(&q->clhash, classid);
48 if (clc == NULL)
49 return NULL;
50 return container_of(clc, struct drr_class, common);
51}
52
53static void drr_purge_queue(struct drr_class *cl)
54{
55 unsigned int len = cl->qdisc->q.qlen;
56 unsigned int backlog = cl->qdisc->qstats.backlog;
57
58 qdisc_reset(cl->qdisc);
59 qdisc_tree_reduce_backlog(cl->qdisc, len, backlog);
60}
61
62static const struct nla_policy drr_policy[TCA_DRR_MAX + 1] = {
63 [TCA_DRR_QUANTUM] = { .type = NLA_U32 },
64};
65
66static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
67 struct nlattr **tca, unsigned long *arg)
68{
69 struct drr_sched *q = qdisc_priv(sch);
70 struct drr_class *cl = (struct drr_class *)*arg;
71 struct nlattr *opt = tca[TCA_OPTIONS];
72 struct nlattr *tb[TCA_DRR_MAX + 1];
73 u32 quantum;
74 int err;
75
76 if (!opt)
77 return -EINVAL;
78
79 err = nla_parse_nested(tb, TCA_DRR_MAX, opt, drr_policy);
80 if (err < 0)
81 return err;
82
83 if (tb[TCA_DRR_QUANTUM]) {
84 quantum = nla_get_u32(tb[TCA_DRR_QUANTUM]);
85 if (quantum == 0)
86 return -EINVAL;
87 } else
88 quantum = psched_mtu(qdisc_dev(sch));
89
90 if (cl != NULL) {
91 if (tca[TCA_RATE]) {
92 err = gen_replace_estimator(&cl->bstats, NULL,
93 &cl->rate_est,
94 qdisc_root_sleeping_lock(sch),
95 tca[TCA_RATE]);
96 if (err)
97 return err;
98 }
99
100 sch_tree_lock(sch);
101 if (tb[TCA_DRR_QUANTUM])
102 cl->quantum = quantum;
103 sch_tree_unlock(sch);
104
105 return 0;
106 }
107
108 cl = kzalloc(sizeof(struct drr_class), GFP_KERNEL);
109 if (cl == NULL)
110 return -ENOBUFS;
111
112 cl->refcnt = 1;
113 cl->common.classid = classid;
114 cl->quantum = quantum;
115 cl->qdisc = qdisc_create_dflt(sch->dev_queue,
116 &pfifo_qdisc_ops, classid);
117 if (cl->qdisc == NULL)
118 cl->qdisc = &noop_qdisc;
119
120 if (tca[TCA_RATE]) {
121 err = gen_replace_estimator(&cl->bstats, NULL, &cl->rate_est,
122 qdisc_root_sleeping_lock(sch),
123 tca[TCA_RATE]);
124 if (err) {
125 qdisc_destroy(cl->qdisc);
126 kfree(cl);
127 return err;
128 }
129 }
130
131 sch_tree_lock(sch);
132 qdisc_class_hash_insert(&q->clhash, &cl->common);
133 sch_tree_unlock(sch);
134
135 qdisc_class_hash_grow(sch, &q->clhash);
136
137 *arg = (unsigned long)cl;
138 return 0;
139}
140
141static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
142{
143 gen_kill_estimator(&cl->bstats, &cl->rate_est);
144 qdisc_destroy(cl->qdisc);
145 kfree(cl);
146}
147
148static int drr_delete_class(struct Qdisc *sch, unsigned long arg)
149{
150 struct drr_sched *q = qdisc_priv(sch);
151 struct drr_class *cl = (struct drr_class *)arg;
152
153 if (cl->filter_cnt > 0)
154 return -EBUSY;
155
156 sch_tree_lock(sch);
157
158 drr_purge_queue(cl);
159 qdisc_class_hash_remove(&q->clhash, &cl->common);
160
161 BUG_ON(--cl->refcnt == 0);
162
163
164
165
166
167 sch_tree_unlock(sch);
168 return 0;
169}
170
171static unsigned long drr_get_class(struct Qdisc *sch, u32 classid)
172{
173 struct drr_class *cl = drr_find_class(sch, classid);
174
175 if (cl != NULL)
176 cl->refcnt++;
177
178 return (unsigned long)cl;
179}
180
181static void drr_put_class(struct Qdisc *sch, unsigned long arg)
182{
183 struct drr_class *cl = (struct drr_class *)arg;
184
185 if (--cl->refcnt == 0)
186 drr_destroy_class(sch, cl);
187}
188
189static struct tcf_proto __rcu **drr_tcf_chain(struct Qdisc *sch,
190 unsigned long cl)
191{
192 struct drr_sched *q = qdisc_priv(sch);
193
194 if (cl)
195 return NULL;
196
197 return &q->filter_list;
198}
199
200static unsigned long drr_bind_tcf(struct Qdisc *sch, unsigned long parent,
201 u32 classid)
202{
203 struct drr_class *cl = drr_find_class(sch, classid);
204
205 if (cl != NULL)
206 cl->filter_cnt++;
207
208 return (unsigned long)cl;
209}
210
211static void drr_unbind_tcf(struct Qdisc *sch, unsigned long arg)
212{
213 struct drr_class *cl = (struct drr_class *)arg;
214
215 cl->filter_cnt--;
216}
217
218static int drr_graft_class(struct Qdisc *sch, unsigned long arg,
219 struct Qdisc *new, struct Qdisc **old)
220{
221 struct drr_class *cl = (struct drr_class *)arg;
222
223 if (new == NULL) {
224 new = qdisc_create_dflt(sch->dev_queue,
225 &pfifo_qdisc_ops, cl->common.classid);
226 if (new == NULL)
227 new = &noop_qdisc;
228 }
229
230 *old = qdisc_replace(sch, new, &cl->qdisc);
231 return 0;
232}
233
234static struct Qdisc *drr_class_leaf(struct Qdisc *sch, unsigned long arg)
235{
236 struct drr_class *cl = (struct drr_class *)arg;
237
238 return cl->qdisc;
239}
240
241static void drr_qlen_notify(struct Qdisc *csh, unsigned long arg)
242{
243 struct drr_class *cl = (struct drr_class *)arg;
244
245 if (cl->qdisc->q.qlen == 0)
246 list_del(&cl->alist);
247}
248
249static int drr_dump_class(struct Qdisc *sch, unsigned long arg,
250 struct sk_buff *skb, struct tcmsg *tcm)
251{
252 struct drr_class *cl = (struct drr_class *)arg;
253 struct nlattr *nest;
254
255 tcm->tcm_parent = TC_H_ROOT;
256 tcm->tcm_handle = cl->common.classid;
257 tcm->tcm_info = cl->qdisc->handle;
258
259 nest = nla_nest_start(skb, TCA_OPTIONS);
260 if (nest == NULL)
261 goto nla_put_failure;
262 if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum))
263 goto nla_put_failure;
264 return nla_nest_end(skb, nest);
265
266nla_put_failure:
267 nla_nest_cancel(skb, nest);
268 return -EMSGSIZE;
269}
270
271static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg,
272 struct gnet_dump *d)
273{
274 struct drr_class *cl = (struct drr_class *)arg;
275 __u32 qlen = cl->qdisc->q.qlen;
276 struct tc_drr_stats xstats;
277
278 memset(&xstats, 0, sizeof(xstats));
279 if (qlen)
280 xstats.deficit = cl->deficit;
281
282 if (gnet_stats_copy_basic(d, NULL, &cl->bstats) < 0 ||
283 gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 ||
284 gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, qlen) < 0)
285 return -1;
286
287 return gnet_stats_copy_app(d, &xstats, sizeof(xstats));
288}
289
290static void drr_walk(struct Qdisc *sch, struct qdisc_walker *arg)
291{
292 struct drr_sched *q = qdisc_priv(sch);
293 struct drr_class *cl;
294 unsigned int i;
295
296 if (arg->stop)
297 return;
298
299 for (i = 0; i < q->clhash.hashsize; i++) {
300 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
301 if (arg->count < arg->skip) {
302 arg->count++;
303 continue;
304 }
305 if (arg->fn(sch, (unsigned long)cl, arg) < 0) {
306 arg->stop = 1;
307 return;
308 }
309 arg->count++;
310 }
311 }
312}
313
314static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
315 int *qerr)
316{
317 struct drr_sched *q = qdisc_priv(sch);
318 struct drr_class *cl;
319 struct tcf_result res;
320 struct tcf_proto *fl;
321 int result;
322
323 if (TC_H_MAJ(skb->priority ^ sch->handle) == 0) {
324 cl = drr_find_class(sch, skb->priority);
325 if (cl != NULL)
326 return cl;
327 }
328
329 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
330 fl = rcu_dereference_bh(q->filter_list);
331 result = tc_classify(skb, fl, &res, false);
332 if (result >= 0) {
333#ifdef CONFIG_NET_CLS_ACT
334 switch (result) {
335 case TC_ACT_QUEUED:
336 case TC_ACT_STOLEN:
337 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
338 case TC_ACT_SHOT:
339 return NULL;
340 }
341#endif
342 cl = (struct drr_class *)res.class;
343 if (cl == NULL)
344 cl = drr_find_class(sch, res.classid);
345 return cl;
346 }
347 return NULL;
348}
349
350static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
351{
352 struct drr_sched *q = qdisc_priv(sch);
353 struct drr_class *cl;
354 int err = 0;
355
356 cl = drr_classify(skb, sch, &err);
357 if (cl == NULL) {
358 if (err & __NET_XMIT_BYPASS)
359 qdisc_qstats_drop(sch);
360 kfree_skb(skb);
361 return err;
362 }
363
364 err = qdisc_enqueue(skb, cl->qdisc);
365 if (unlikely(err != NET_XMIT_SUCCESS)) {
366 if (net_xmit_drop_count(err)) {
367 cl->qstats.drops++;
368 qdisc_qstats_drop(sch);
369 }
370 return err;
371 }
372
373 if (cl->qdisc->q.qlen == 1) {
374 list_add_tail(&cl->alist, &q->active);
375 cl->deficit = cl->quantum;
376 }
377
378 sch->q.qlen++;
379 return err;
380}
381
382static struct sk_buff *drr_dequeue(struct Qdisc *sch)
383{
384 struct drr_sched *q = qdisc_priv(sch);
385 struct drr_class *cl;
386 struct sk_buff *skb;
387 unsigned int len;
388
389 if (list_empty(&q->active))
390 goto out;
391 while (1) {
392 cl = list_first_entry(&q->active, struct drr_class, alist);
393 skb = cl->qdisc->ops->peek(cl->qdisc);
394 if (skb == NULL) {
395 qdisc_warn_nonwc(__func__, cl->qdisc);
396 goto out;
397 }
398
399 len = qdisc_pkt_len(skb);
400 if (len <= cl->deficit) {
401 cl->deficit -= len;
402 skb = qdisc_dequeue_peeked(cl->qdisc);
403 if (unlikely(skb == NULL))
404 goto out;
405 if (cl->qdisc->q.qlen == 0)
406 list_del(&cl->alist);
407
408 bstats_update(&cl->bstats, skb);
409 qdisc_bstats_update(sch, skb);
410 sch->q.qlen--;
411 return skb;
412 }
413
414 cl->deficit += cl->quantum;
415 list_move_tail(&cl->alist, &q->active);
416 }
417out:
418 return NULL;
419}
420
421static unsigned int drr_drop(struct Qdisc *sch)
422{
423 struct drr_sched *q = qdisc_priv(sch);
424 struct drr_class *cl;
425 unsigned int len;
426
427 list_for_each_entry(cl, &q->active, alist) {
428 if (cl->qdisc->ops->drop) {
429 len = cl->qdisc->ops->drop(cl->qdisc);
430 if (len > 0) {
431 sch->q.qlen--;
432 if (cl->qdisc->q.qlen == 0)
433 list_del(&cl->alist);
434 return len;
435 }
436 }
437 }
438 return 0;
439}
440
441static int drr_init_qdisc(struct Qdisc *sch, struct nlattr *opt)
442{
443 struct drr_sched *q = qdisc_priv(sch);
444 int err;
445
446 err = qdisc_class_hash_init(&q->clhash);
447 if (err < 0)
448 return err;
449 INIT_LIST_HEAD(&q->active);
450 return 0;
451}
452
453static void drr_reset_qdisc(struct Qdisc *sch)
454{
455 struct drr_sched *q = qdisc_priv(sch);
456 struct drr_class *cl;
457 unsigned int i;
458
459 for (i = 0; i < q->clhash.hashsize; i++) {
460 hlist_for_each_entry(cl, &q->clhash.hash[i], common.hnode) {
461 if (cl->qdisc->q.qlen)
462 list_del(&cl->alist);
463 qdisc_reset(cl->qdisc);
464 }
465 }
466 sch->q.qlen = 0;
467}
468
469static void drr_destroy_qdisc(struct Qdisc *sch)
470{
471 struct drr_sched *q = qdisc_priv(sch);
472 struct drr_class *cl;
473 struct hlist_node *next;
474 unsigned int i;
475
476 tcf_destroy_chain(&q->filter_list);
477
478 for (i = 0; i < q->clhash.hashsize; i++) {
479 hlist_for_each_entry_safe(cl, next, &q->clhash.hash[i],
480 common.hnode)
481 drr_destroy_class(sch, cl);
482 }
483 qdisc_class_hash_destroy(&q->clhash);
484}
485
486static const struct Qdisc_class_ops drr_class_ops = {
487 .change = drr_change_class,
488 .delete = drr_delete_class,
489 .get = drr_get_class,
490 .put = drr_put_class,
491 .tcf_chain = drr_tcf_chain,
492 .bind_tcf = drr_bind_tcf,
493 .unbind_tcf = drr_unbind_tcf,
494 .graft = drr_graft_class,
495 .leaf = drr_class_leaf,
496 .qlen_notify = drr_qlen_notify,
497 .dump = drr_dump_class,
498 .dump_stats = drr_dump_class_stats,
499 .walk = drr_walk,
500};
501
502static struct Qdisc_ops drr_qdisc_ops __read_mostly = {
503 .cl_ops = &drr_class_ops,
504 .id = "drr",
505 .priv_size = sizeof(struct drr_sched),
506 .enqueue = drr_enqueue,
507 .dequeue = drr_dequeue,
508 .peek = qdisc_peek_dequeued,
509 .drop = drr_drop,
510 .init = drr_init_qdisc,
511 .reset = drr_reset_qdisc,
512 .destroy = drr_destroy_qdisc,
513 .owner = THIS_MODULE,
514};
515
516static int __init drr_init(void)
517{
518 return register_qdisc(&drr_qdisc_ops);
519}
520
521static void __exit drr_exit(void)
522{
523 unregister_qdisc(&drr_qdisc_ops);
524}
525
526module_init(drr_init);
527module_exit(drr_exit);
528MODULE_LICENSE("GPL");
529
