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