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